WO2017010384A1

WO2017010384A1 - Wiring structure, solar cell module, and solar cell

Info

Publication number: WO2017010384A1
Application number: PCT/JP2016/070069
Authority: WO
Inventors: 達也北原; 有史上田; 哲也京極; 正孝上田; 久成尾之内
Original assignee: 日東電工株式会社
Priority date: 2015-07-10
Filing date: 2016-07-07
Publication date: 2017-01-19

Abstract

Provided is a wiring structure having high connection reliability and excellent wiring workability. According to the present invention, a wiring structure is provided which bridges over from the upper surface of one solar cell to the lower surface of the other solar cell of two solar cells arranged in a solar cell module. Said wiring structure has a first region which corresponds to the one solar cell and a second region which corresponds to the other solar cell. Further, the wiring structure is provided with a conductive section which is continuous from the first region to the second region, a first resin layer which is disposed above the conductive section in the first region, and a second resin layer which is disposed below the conductive section in the second region. Also, the conductive section is partially disposed in the first region.

Description

[Name of invention determined by ISA based on Rule 37.2] Wiring structure, solar cell module and solar cell

The present invention relates to a wiring structure and a solar cell module. Specifically, the present invention relates to a wiring structure and a solar cell module that are preferably used for a solar cell module.
This application includes Japanese Patent Application No. 2015-139211 filed on July 10, 2015, Japanese Patent Application No. 2015-218976 filed on November 6, 2015, and March 18, 2016. Claims priority based on the filed Japanese Patent Application No. 2016-054789, the entire contents of which are incorporated herein by reference.

Solar cell modules that convert light energy into electric power are widely used as clean power generators. The solar cell module includes a solar cell and a wiring connected to the cell, and the power generated in the cell through the wiring is configured to be supplied to the outside. Patent documents 1 to 8 are cited as documents disclosing this type of prior art. Patent Documents 1 to 6 relate to a solar cell module in which an n-type electrode is partially disposed on the front surface side of the solar battery cell and a p-type electrode is disposed on the back surface side. The present invention relates to a solar cell module that employs a back contact method in which both electrodes are arranged on the back side.

Japanese Patent Application Publication No. 2005-72115 Japanese Patent Application Publication No. 2013-232496 Japanese published patent publication 2005-536894 Japanese Patent No. 5185913 Japanese Patent Application Publication No. 2014-63978 Japanese Patent Application Publication No. 2014-3064 Japanese Patent Application Publication No. 2010-41009 Japanese Patent Application Publication No. 2011-238849

In solar cell modules of the type having electrodes on the front and back surfaces, for example, the structures disclosed in

Patent Documents

1 and 2 require that the wiring of solar cells must be individually joined using solder etc. And takes time. When heating is performed at the time of bonding, such as solder bonding, the characteristics of the cell may be reduced by heating, or the cell may be warped or cracked. Solder joints also have a problem of flux contamination.

Patent Documents 3 to 6 propose a technique in which a solar battery cell is sandwiched from above and below by a previously formed wiring pattern, and the upper and lower wiring patterns are conducted between the cells. For example, a solar cell module described in Patent Document 5 prepares a pair of sealing sheets having metal wiring on the surface, sandwiches a plurality of solar cells between the pair of sealing sheets, and the metal wiring and the solar cell. By pressing and heating the battery cells in contact with each other, a plurality of solar battery cells are electrically connected without requiring solder bonding. However, the conduction between the upper and lower metal wirings includes factors such as securing the contact area and accuracy of alignment, and the conduction state (contact state) of the metal wirings may be impaired by the flow of the sealing resin or the like. is there. These can cause a decrease in current collection efficiency and wiring defects. In

Patent Documents

3, 4 and 6, a low melting point alloy or a conductive film is used to connect the upper and lower wiring patterns, but the same as Patent Document 5 in that the wiring patterns separated vertically are brought into contact when the module is constructed. This method is used, and the reliability of the upper and lower wiring connections is not perfect.

The present invention was created in view of the above circumstances, and an object thereof is to provide a wiring structure having high connection reliability and excellent wiring workability. Another related object is to provide a solar cell module having high connection reliability and excellent power generation efficiency and durability.

According to the present invention, there is provided a wiring structure (solar cell module wiring structure) that extends from the upper surface of one of the two solar cells arranged in the solar cell module to the lower surface of the other solar cell. Provided. The wiring structure includes a first region corresponding to the one solar battery cell and a second region corresponding to the other solar battery cell. In addition, the wiring structure includes a conductive portion continuous from the first region to the second region, a first resin layer disposed above the conductive portion in the first region, and the second region in the second region. A second resin layer disposed below the conductive portion. The conductive portion is partially disposed in the first region.
According to the above configuration, the conductive portion is connected to the upper and lower sides of the two solar cells in a continuous structure such as an integral type, so that the wiring is compared with the method in which the two upper and lower separated wirings are overlapped and connected. Excellent connection reliability. There is no need to align the upper and lower wires. Further, since the conductive portion is supported by the first resin layer and the second resin layer, the wiring structure is easy to handle and has excellent wiring workability regardless of the shape of the conductive portion. Furthermore, the first resin layer and the second resin layer are positioned between the conductive portion and the sealing resin, respectively, when the solar cell module is constructed, thereby preventing the flow of the sealing resin toward the conductive portion, for example, sealing The phenomenon in which the resin flow adversely affects the contact state between the solar battery cell and the conductive portion is prevented. As a result, the contact state between the solar battery cell and the conductive portion is kept good, and a decrease in current collection efficiency is prevented.

In a preferred aspect of the technology disclosed herein (including a wiring structure, a solar cell module, and a method for manufacturing them, the same applies hereinafter), the conductive portion extends from the first region to the second region. It is comprised from this. Further, it is preferable that the plurality of conductive lines are arranged at intervals. By comprising in this way, high current collection efficiency is realizable, suppressing the increase in shadow loss.

In a preferred aspect of the technology disclosed herein, the conductive wire is a copper wire plated. The plating is more preferably silver plating. In a more preferred embodiment, the silver plating has a purity of 99.7% by weight or more. With this configuration, power generation efficiency is improved.

In a preferred aspect of the technology disclosed herein, the conductive wire exhibits a diffuse reflectance of 60% or more. With this configuration, power generation efficiency is improved.

In a preferred aspect of the technology disclosed herein, the first resin layer and the second resin layer are both adhesive layers. Thereby, the conductive part is satisfactorily fixed to the first resin layer and the second resin layer using the adhesive force of the pressure-sensitive adhesive layer. Moreover, a 1st resin layer and a 2nd resin layer can adhere | attach a photovoltaic cell and a conductive part, and can maintain the contact | adherence state favorably by adhere | attaching a photovoltaic cell over a conductive part. In a more preferred embodiment, the first resin layer and the second resin layer are both crosslinked adhesive layers. The crosslinked pressure-sensitive adhesive layer exhibits preferable physical properties (typically storage elastic modulus) as the first and second resin layers.

In a preferred aspect of the technology disclosed herein, the storage elastic modulus (frequency 1 Hz, strain 0.1%, 150 ° C.) of each of the first resin layer and the second resin layer is 5000 Pa or more, and The tan δ at 80 ° C. to 150 ° C. is less than 0.4. By comprising in this way, the electroconductive part can be made to contact | abut to the solar cell surface favorably at the time of solar cell module construction using the characteristic of the 1st resin layer and the 2nd resin layer.

Moreover, according to this invention, a wiring structure with a release liner is provided. The wiring structure with release liner includes: any of the wiring structures disclosed herein; a first release liner disposed on an upper surface of the first resin layer in the first region; A second release liner disposed on the lower surface of the conductive portion; a third release liner disposed on the upper surface of the conductive portion in the second region; and a lower surface of the second resin layer in the second region. A fourth release liner.
By using the wiring structure with a release liner having the above configuration, the solar cell module can be manufactured efficiently and accurately. Although not particularly limited, for example, the second release liner and the third release liner are peeled from the wiring structure, and the surface of one solar battery cell is overlaid on the exposed portion of the first region of the wiring structure. In addition, the back surface of the other solar cell is overlaid on the exposed portion of the second region. Thereafter, the first release liner and the fourth release liner are peeled off, and the solar battery module connected to the wiring structure is sandwiched between two sealing resins from above and below to form a solar battery module. it can. By such a method with excellent workability, wiring excellent in connection reliability is realized.

In addition, according to the present invention, a wiring structure (a wiring structure for a solar battery module) spans from the upper surface of one of the two solar cells arranged in the solar battery module to the lower surface of the other solar cell. ) Is provided. The wiring structure includes a first region corresponding to the one solar battery cell and a second region corresponding to the other solar battery cell. The wiring structure includes a conductive portion that continues from the first region to the second region, and a resin layer that is disposed above the conductive portion in the first region. The conductive portion is partially disposed in the first region. With such a configuration, a wiring structure having high connection reliability and excellent wiring workability can be obtained. The resin layer corresponds to the first resin layer described above.

Moreover, according to the present invention, a wiring structure with a release liner is provided. The wiring structure with release liner includes: any of the wiring structures disclosed herein; a first release liner disposed on an upper surface of the first resin layer in the first region; A second release liner disposed on the lower surface of the conductive portion. A solar cell module can be efficiently manufactured by using the wiring structure with a release liner having the above-described configuration.

Further, according to the present invention, a structure having a first region and a second region is provided. The structure includes a conductive portion that continues from the first region to the second region, and a resin layer that is disposed on one surface of the conductive portion in the first region. The conductive portion is partially disposed in the first region. The structure according to a preferred aspect includes, as the resin layer, a first resin layer disposed on a first surface (for example, an upper side or an upper surface) of the conductive portion in the first region, The second region includes a second resin layer disposed on a second surface (for example, a lower side or a lower surface) of the conductive portion in the second region.

Also, according to the present invention, a solar cell module including any one of the structures or wiring structures disclosed herein is provided. By using the structure, a solar cell module can be constructed efficiently and accurately. Moreover, since the wiring in the module is excellent in connection reliability, excellent current collection efficiency can be realized reliably and stably.

Moreover, according to this invention, a solar cell module is provided. The solar cell module includes a plurality of solar cells arranged at intervals and an upper surface of one solar cell of two adjacent solar cells out of the plurality of solar cells from the other solar cell. A conductive part that is spanned across the lower surface and electrically connects the two adjacent solar cells; a first resin layer disposed above one of the two adjacent solar cells; A second resin layer disposed below the other solar cell of the two adjacent solar cells. The conductive portion is disposed between the one solar cell and the first resin layer, and between the other solar cell and the second resin layer, and the one solar cell. It is partially arranged on the upper surface of the battery cell.
According to the above configuration, the conductive portion is connected to the top and bottom of the two solar cells in a continuous structure, so that the connection reliability of the wiring is improved as compared to the method of connecting the two wirings separated from each other vertically. Excellent. The first resin layer and the second resin layer are located between the conductive portion and the sealing resin, respectively, when the solar cell module is constructed, and prevent the sealing resin from flowing toward the conductive portion. Thereby, for example, an event in which the flow of the sealing resin adversely affects the contact state between the solar battery cell and the conductive portion is prevented. As a result, the contact state between the solar battery cell and the conductive portion is kept good, and a decrease in current collection efficiency is prevented. In other words, the solar cell module disclosed here is excellent in power generation efficiency and durability.

In a preferred aspect of the technology disclosed herein, the conductive portion is composed of a plurality of conductive lines extending from the upper surface of one of the two adjacent solar cells to the lower surface of the other solar cell. ing. Further, it is preferable that the plurality of conductive lines are arranged at intervals. By comprising in this way, high current collection efficiency is realizable, suppressing the increase in shadow loss.

In a preferred aspect of the technology disclosed herein, the first resin layer is not disposed above the other solar battery cell, and the second resin layer is disposed below the one solar battery cell. Not placed. In such a configuration, the effect of the technique disclosed herein is realized.

In a preferred aspect of the technology disclosed herein, the solar cell module includes a sealing resin that covers the plurality of solar cells from the outside of the first resin layer and the second resin layer. The solar cell module more preferably includes a surface covering member and a back surface covering member that sandwich the plurality of solar cells from the outside of the sealing resin. In other words, the solar cell module includes, from above, sealing resin / first resin layer / conductive portion (front side conductive portion) / solar battery cell / conductive portion (back side conductive portion) / second resin layer / sealing resin. May have a cross-sectional structure laminated in this order. Further, the solar cell module may be one in which the surface covering member is disposed on the sealing resin positioned above and the back surface covering member is disposed below the sealing resin positioned below. The front surface side conductive portion and the back surface side conductive portion are separate members.

In a preferred aspect of the technology disclosed herein, an electrode is provided on each surface of the plurality of solar cells. The electrode includes a plurality of first linear portions extending linearly along the plurality of conductive lines, and a plurality of second linear portions extending linearly so as to intersect the first linear portions. And having. A first linear portion arranged along the conductive wire is provided on the surface electrode of the solar battery cell, and by overlapping this with the conductive wire, the contact area between the conductive wire and the electrode is increased, and the current collection efficiency is increased. improves. Further, since the surface electrode of the solar battery cell is in continuous contact (line contact) with the conductive wire at the first linear portion, contact failure occurs even when the contact portion has a float or the like. It is difficult and excellent in conduction reliability. The technique disclosed here may be such that the surface electrode of the solar battery cell and the conductive wire are brought into conduction by contact without using an adhesive means (direct adhesive means). In such a configuration, the advantage of increasing the contact area and improving the conduction reliability is great.

In the present specification, the wiring formed by the contact between the surface electrode of the solar battery cell and the conductive wire is also referred to as an adhesive means such as solder joint or conductive adhesive (direct adhesive means. Also referred to as conductive adhesive means). The same)) may be referred to as “physical contact” in order to distinguish it from the joint used. Physical contact refers to a contact state or a contact method in which conduction is achieved by contact only by contact without using an adhesive means. Although the 1st resin layer and 2nd resin layer which are disclosed here may have adhesiveness, they play the role which assists and hold | maintains the said physical contact, and grasp it as a thing different from the said adhesion | attachment means. Is done. “Solderless wiring” that does not use low melting point metal such as solder is a typical example of physical contact type wiring. In this specification, a solar cell module constructed by physical contact type wiring may be referred to as a physical contact type solar cell module. Since the physical contact type solar cell module can be conducted without heating, cell characteristics can be prevented from being deteriorated due to heating. Moreover, according to the solar cell module that performs solderless wiring (solderless solar cell module), not only the above-mentioned flux contamination can be avoided, but also problems such as leaching and cratering caused by solder bonding can be solved.

In a preferred aspect of the technology disclosed herein, the width of the first linear portion is smaller than the width of the conductive line. In the technique disclosed here, if the first linear portion is provided on the surface electrode of the solar battery cell and the surface electrode and the conductive wire are in linear contact, the width of the first linear portion is determined. Even if it is smaller than the width of the conductive wire, the current collection efficiency can be sufficiently secured by the conductive wire. This is a point that is essentially different from the conventional bus bar electrode configured to be wider than the wiring material in order to ensure the bonding strength. Making the first linear portion narrower than the conductive line is also beneficial in terms of reducing shadow loss and saving electrode material.

In a preferred aspect of the technology disclosed herein, a ratio (W1 / W2) of the width W1 of the first linear portion and the width W2 of the second linear portion is in a range of 0.1 to 10. Is within. By setting the width of the first and second linear portions within a predetermined range, various electrode forming means such as screen printing can be simultaneously applied to the first and second linear portions, and production Improves. Further, since the width of each linear portion of the electrode falls within a predetermined range, accurate electrode formation can be realized.

In a preferred aspect of the technology disclosed herein, the electrode provided on the surface of the solar cell is in contact with the conductive wire at the first linear portion. More preferably, no adhesive means is used for the contact. According to the technology disclosed herein, as described above, wiring in the solar cell module is possible without using an adhesive means such as soldering or conductive adhesive, so that the current collection efficiency and the conduction reliability are improved. In addition, productivity can be improved.

Moreover, according to the present invention, a method for manufacturing a solar cell module is provided. This manufacturing method is carried out using any of the structures or wiring structures disclosed herein. According to the said manufacturing method, the solar cell module excellent in wiring workability | operativity and connection reliability is implement | achieved. Specifically, the manufacturing method includes a step of wiring a solar battery cell using any of the structures or wiring structures disclosed herein. In one preferred embodiment, a method for manufacturing a solar cell module includes: providing at least two solar cells; preparing any of the structures or wiring structures disclosed herein; and one solar cell Crossing the structure from the upper surface of the solar cell to the lower surface of the other solar battery cell. More specifically, the lower surface of the first region (specifically, the conductive portion of the first region) of the structure is brought into contact with the front surface of the one solar cell, and the other A step of bringing the upper surface of the second region (specifically, the conductive portion of the second region) of the structure into contact with the back surface of one solar battery cell.

In a preferred aspect of the manufacturing method disclosed herein, the structure is prepared as a structure with a release liner (wiring structure) including two or four release liners. When the structure with a release liner includes two release liners, the first release liner disposed on the upper surface of the first resin layer in the first region, and the lower surface of the conductive portion in the first region. And a second release liner. When the structure with a release liner includes four release liners, the first release liner is disposed on the upper surface of the first resin layer in the first region, and is disposed on the lower surface of the conductive portion in the first region. A second release liner, a third release liner disposed on the upper surface of the conductive portion in the second region, and a fourth release liner disposed on the lower surface of the second resin layer in the second region. It can be preferably prepared in the form of comprising.

Moreover, according to this specification, a solar cell module provided with the several photovoltaic cell arranged at intervals is provided. The solar cell module is configured such that two adjacent solar cells are extended from the upper surface of one of the two adjacent solar cells out of the plurality of solar cells to the lower surface of the other solar cell. A plurality of conductive wires are provided for electrical connection. In this solar cell module, an electrode is provided on each surface of the plurality of solar cells. The electrode includes a plurality of first linear portions extending linearly along the plurality of conductive lines and a plurality of second lines extending linearly so as to intersect the first linear portions. And a shaped portion. Furthermore, the width of the first linear portion is smaller than the width of the conductive line.
According to said structure, since the 1st linear part of an electrode overlaps along a conductive wire, the contact area of a conductive wire and an electrode becomes large and current collection efficiency improves. In addition, since the surface electrode of the solar battery cell is in line contact with the conductive wire at the first linear portion, even when there is a floating or the like in the contact portion, poor contact is unlikely to occur and the conduction reliability is excellent. Furthermore, by making the width of the first linear portion smaller than the width of the conductive line, it is possible to realize a reduction in shadow loss and a reduction in electrode material without impairing the current collection efficiency. The solar cell module having the above configuration is preferably applied to an embodiment in which wiring by physical contact is performed. In particular, it is meaningful to incorporate the wiring structure disclosed herein.

Moreover, according to this specification, a photovoltaic cell is provided. An electrode is provided on the surface of the solar battery cell. The electrode includes a plurality of first linear portions extending linearly and a plurality of second linear portions extending linearly so as to intersect the first linear portions. Moreover, the width | variety of a said 1st linear part is smaller than the width | variety of the electrically conductive line which electrically connects the said photovoltaic cell and another photovoltaic cell.
According to the solar battery cell having the above-described configuration, the first linear portion of the surface electrode and the conductive wire are arranged so as to coincide with each other, thereby improving the current collection efficiency and reducing the shadow loss. And electrode material savings. The solar cell having the above configuration is particularly preferable as a solar cell for the solar cell module disclosed herein. By using the solar cell in the physical contact solar cell module or other solar cell module disclosed herein, the current collection efficiency and the conduction reliability are improved.

It is a top view which shows typically the wiring structure which concerns on one Embodiment. FIG. 2 is a cross-sectional view taken along line II-II of the wiring structure of FIG. FIG. 3 is a view corresponding to FIG. 2, and is a cross-sectional view schematically showing a wiring structure with a release liner according to an embodiment. It is explanatory drawing of the wiring method of the solar cell module which concerns on 1st Embodiment. It is sectional drawing which shows typically the principal part of the solar cell module which concerns on 1st Embodiment. It is a typical top view which expands and shows a part of surface of the photovoltaic cell concerning 2nd Embodiment. It is an expansion disassembled perspective view for demonstrating the arrangement | positioning relationship between the surface electrode of the photovoltaic cell which concerns on 2nd Embodiment, and a conductive wire. It is a figure for demonstrating the arrangement | positioning relationship between the surface electrode of a photovoltaic cell and conductive wire which concerns on 2nd Embodiment, Comprising: It is typical sectional drawing which expands and shows the contact state of a conductive wire and a surface electrode. . It is EL test | inspection image of the photovoltaic cell in the solar cell module for a test. It is a graph which shows the measurement result of the diffuse reflectance (%) of the electrically-conductive part surface in Experiment 2, and short circuit current Jsc (mA / cm < ² >). It is a graph which shows the relationship between the plating thickness (micrometer) in Experiment 3, and a diffuse reflectance (%). It is a graph which shows the result of the dump heat (DH) test in Experiment 4. FIG. 10 is a top view schematically showing the arrangement state of conductive lines on the upper surface of a solar battery cell related to Sample 5-1 in Experiment 5 (effect verification test). FIG. 10 is a top view schematically showing a test solar cell module according to Sample 5-1 in Experiment 5 (effect verification test). FIG. 10 is a top view schematically showing the arrangement state of conductive lines on the upper surface of a solar battery cell related to sample 5-2 in Experiment 5 (effect verification test). It is a graph which shows the relationship between the amount of distortion deformation (mm) and resistance value change (times) in Experiment 5 (effect verification test). It is typical explanatory drawing of the distortion deformation amount (mm) in Experiment 5 (effect verification test). It is a schematic top view for demonstrating the arrangement | positioning state of the conductive wire of the photovoltaic cell upper surface which concerns on the sample 6-1 in Experiment 6 (effect verification test), (a) is a figure which shows the state before conductive wire arrangement | positioning (B) is a figure which shows the state after conductive line arrangement | positioning. It is a schematic top view for demonstrating the arrangement | positioning state of the electrically conductive line of the photovoltaic cell upper surface which concerns on the sample 6-2 in experiment 6 (effect verification test), Comprising: (a) is a figure which shows the state before conductor line arrangement | positioning (B) is a figure which shows the state after conductive line arrangement | positioning.

Hereinafter, preferred embodiments of the present invention will be described. Note that matters other than the matters specifically mentioned in the present specification and necessary for the implementation of the present invention are based on the teachings on the implementation of the invention described in the present specification and the common general technical knowledge at the time of filing. Can be understood by those skilled in the art. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field. Further, in the following drawings, members / parts having the same action are described with the same reference numerals, and overlapping descriptions may be omitted or simplified. In addition, the embodiments described in the drawings are schematically illustrated in order to clearly explain the present invention, and do not necessarily accurately represent the size and scale of a product actually provided.

<< Wiring structure >>
FIG. 1 is a top view schematically showing a wiring structure according to an embodiment, and FIG. 2 is a cross-sectional view taken along the line II-II of the wiring structure of FIG.

As shown in FIGS. 1 and 2, the wiring structure 1 includes a conductive portion 30, a first resin layer 50 disposed above the conductive portion 30, and a second resin layer 60 disposed below the conductive portion 30. And comprising. In addition, the wiring structure 1 has a first region 10 and a second region 12. The first region 10 and the second region 12 are regions corresponding to one and the other of two adjacent solar cells in the solar cell module, respectively. Specifically, when the solar cell module is constructed, the first region 10 is a region overlapping with one solar cell, and the second region 12 is a region overlapping with the other solar cell. In this embodiment, each of the first region 10 and the second region 12 is a region having a quadrangular shape when the wiring structure 1 is viewed from above, and is between the first region 10 and the second region 12. Is provided with a predetermined interval. The solar battery cell of this embodiment has a substantially square shape (approximately 15.5 cm × 15.5 cm), and the first region 10 and the second region 12 have the same shape and the same size.

The conductive part 30 has a continuous shape from the first region 10 to the second region 12. The conductive portion 30 is arranged so as to extend to almost both ends of the wiring structure 1 in the arrangement direction of the first region 10 and the second region 12 (which may also be the arrangement direction of solar cells). Further, the conductive portion 30 is partially disposed in the first region 10. The conductive portion 30 is also partially disposed in the second region 12. Specifically, the conductive portion 30 is composed of a plurality of conductive lines 40 extending from the first region 10 to the second region 12. The plurality of conductive lines 40 are arranged at intervals from each other along the arrangement direction of the first region 10 and the second region 12. The conductive lines 40 are arranged in a straight line so as to be parallel to each other, and extend to almost both ends of the wiring structure 1 in the arrangement direction of the first region 10 and the second region 12. In other words, each conductive wire 40 extends in a straight line from the outer end portion of the first resin layer 50 in the first region 10 to the outer end portion of the second resin layer 60. In this embodiment, a copper wire having a width of 0.8 mm and a thickness of 0.25 mm is used as the conductive wire 40.

The first resin layer 50 is disposed in the first region 10. The first resin layer 50 has substantially the same shape and size as the first region 10. Therefore, the first resin layer 50 of this embodiment has a substantially square shape having a size of about 15.5 cm × 15.5 cm. In such a first region 10, the first resin layer 50 is disposed above the conductive portion 30 (specifically, the conductive wire 40). The upper surface of the first resin layer 50 constitutes a part of the outer surface (upper surface) of the wiring structure 1 (the upper surface of the first region 10). On the other hand, the lower surface of the first region 10 of the wiring structure 1 is constituted by the first resin layer 50 and the conductive portion 30. In this embodiment, the first resin layer 50 is a transparent adhesive layer having a thickness of about 0.05 mm, and the conductive wire 40 is bonded to the surface of the first resin layer 50. In addition, the upper and lower sides of the wiring structure in the present specification correspond to the front and back of the solar battery cell described later, and thus correspond to the front and back (up and down) of the solar battery module. Depending on how the solar cell module is installed, the top and bottom may not necessarily be strictly up and down, so the top and bottom of the wiring structure is not limited to exact top and bottom, and is understood to indicate a relative positional relationship. The

The second resin layer 60 is disposed in the second region 12. The second resin layer 60 has substantially the same shape and size as the second region 12. Therefore, the second resin layer 60 of this embodiment has a substantially square shape having a size of approximately 15.5 cm × 15.5 cm. In such a second region 12, the second resin layer 60 is disposed below the conductive portion 30 (specifically, the conductive wire 40). The lower surface of the second resin layer 60 constitutes a part of the outer surface (lower surface) of the wiring structure 1 (the lower surface of the second region 12). In this embodiment, the second resin layer 60 is a transparent adhesive layer having a thickness of about 0.05 mm, and the conductive wire 40 is bonded to the surface of the second resin layer 60. In this embodiment, the upper surface of the second region 12 of the wiring structure 1 is constituted by the second resin layer 60 and the conductive portion 30. In addition, the 2nd resin layer 60 arrange | positioned at the back surface of a photovoltaic cell does not need to be transparent.

≪Wiring structure with release liner≫
FIG. 3 is a view corresponding to FIG. 2, and is a cross-sectional view schematically showing a wiring structure with a release liner according to an embodiment.

The wiring structure 1 can be provided for manufacturing a solar cell module in a form protected by a release liner. As shown in FIG. 3, the wiring structure 2 with a release liner includes the wiring structure 1 and four release liners covering the upper and lower surfaces of the first region 10 and the upper and lower surfaces of the second region 12, respectively. A first release liner 70, a second release liner 72, a third release liner 74, and a fourth release liner 76 are provided. The first release liner 70 is disposed on the upper surface of the first resin layer 50 in the first region 10 of the wiring structure 1. The second release liner 72 is disposed on the lower surface of the conductive portion 30 in the first region 10. The third release liner 74 is disposed on the upper surface of the conductive portion 30 in the second region 12. The fourth release liner 76 is disposed on the lower surface of the second resin layer 60 in the second region 12. As described above, the wiring in the solar cell module is efficiently arranged by arranging the release liner so that it can be separated into the first region 10 and the second region 12 on each of the upper and lower surfaces of the wiring structure 1. Can be done well. This point will be described later. In this embodiment, as the

release liners

70, 72, 74, and 76, a polyester resin film whose one side has been subjected to a release treatment is used.

The wiring structure 1 and the wiring structure 2 with a release liner as described above can be manufactured, for example, by the following method. First, the conductive part 30 (for example, a plurality of conductive lines 40) is prepared. Moreover, the 1st resin layer 50 and the 2nd resin layer 60 by which one side was protected by the release liner (For example, the 1st release liner 70 and the 4th release liner 76) are prepared, respectively. Then, the exposed surface (for example, the surface opposite to the surface protected by the first release liner 70) of the first resin layer 50 is fixed (for example, bonded) to a part of the conductive portion 30 (the portion that becomes the first region 10). ) Further, the exposed surface of the second resin layer 60 (for example, the surface opposite to the surface protected by the fourth release liner 76) is fixed to the other part of the conductive portion 30 (the portion that becomes the second region 12) ( For example, bonding). The second resin layer 60 is fixed to the surface of the conductive part 30 opposite to the side on which the first resin layer 50 is fixed. Thereafter, the second release liner 72 is bonded to the exposed surface of the first resin layer 50 in the portion that becomes the first region 10 and the conductive portion 30, and the exposed surface of the second resin layer 60 in the portion that becomes the second region. A third release liner 74 is bonded to the conductive portion 30. In this way, the wiring structure 1 and the wiring structure 2 with the release liner are manufactured. The timing of molding (processing into a predetermined shape) of the first resin layer 50 and the second resin layer 60 is not particularly limited, and the first resin layer 50 and the second resin layer 60 processed into a predetermined shape are prepared in advance. The first resin layer 50 and the second resin layer 60 may be fixed to the conductive portion 30, and then the first resin layer 50 and the second resin layer 60 may be formed in a predetermined shape. It is also possible to cut to size.

In a preferred embodiment, the long first resin layer 50 and the long second resin layer 60 are arranged in parallel (and horizontally, for example) at a predetermined interval, and the first resin layer 50 and the second resin layer 50 are arranged in parallel. From the direction intersecting (typically orthogonal) with the longitudinal direction of the resin layer 60, the conductive portion 30 (typically the conductive wire 40) passes above the second resin layer 60 and below the first resin layer 50. By inserting the first resin layer 50 and the second resin layer 60 in such a manner as to intersect (typically orthogonal) their longitudinal direction, the wiring structure 1 can be produced. In this case, the upper surface of the first resin layer 50 and the lower surface of the second resin layer 60 may typically be in a form protected by a release liner, respectively. Further, in the production of the wiring structure 1, the first resin layer 50 and the second resin layer 60 have a step (insertion space) when viewed from the side from the viewpoint of ease of insertion of the conductive portion 30. It is preferable to arrange in such a manner. For example, a roll of a long first resin layer 50 whose one surface is covered with a release liner and a roll of a long second resin layer 60 whose one surface is covered with a release liner are arranged side by side. The wiring structure 1 is continuously produced by arranging, drawing out the first resin layer 50 and the second resin layer 60 in parallel, sequentially inserting the conductive portions 30 therebetween, and cutting them at predetermined intervals. can do. When both the first resin layer 50 and the second resin layer 60 are pressure-sensitive adhesive layers, the conductive portion 30 is inserted into a predetermined position with respect to the first resin layer 50 and the second resin layer 60 and then appropriately By pressing at a proper timing, the conductive portion 30 can be satisfactorily fixed to the first resin layer 50 and the second resin layer 60.

≪Solar cell module≫
(First embodiment)
FIG. 4 is an explanatory diagram of a solar cell module wiring method according to the first embodiment, and FIG. 5 is a cross-sectional view schematically showing main parts of the solar cell module according to the first embodiment.

Next, wiring in the solar cell module 100 performed using the wiring structure 1 (which may be the wiring structure 2 with a release liner) and the solar cell module 100 obtained thereby will be described. As shown in FIG. 4, the solar cell 110 a is disposed below the first region 10 of the wiring structure 1, and the solar cell 110 b is disposed above the second region 12. When the lower surface of the first region 10 is covered with a release liner (for example, a second release liner), the release liner is peeled off from the lower surface of the first region 10 and the solar cell is formed on the conductive portion 30 of the first region 10. The front surface of the cell 110a is brought into contact. In addition, when the upper surface of the second region 12 is covered with a release liner (for example, a third release liner), the release liner is peeled off from the upper surface of the second region 12 to form the conductive portion 30 in the second region 12. The back surface of the solar battery cell 110b is brought into contact. Thereby, the upper surface of the solar battery cell 110 a and the lower surface of the solar battery cell 110 b are electrically connected by the conductive portion 30 of the wiring structure 1. And the upper surface of the 2nd area | region 12 of another wiring structure 1 is made to contact | abut to the lower surface of the photovoltaic cell 110a, and the lower surface of the 1st area | region 10 of another wiring structure 1 is made to contact the upper surface of the photovoltaic cell 110b. Abut. By repeating this operation by applying it to other solar cells (for example,

solar cells

110c and 110d), the vertical wiring of the plurality of

solar cells

110a, 110b, 110c and 110d as shown in FIG. 5 is completed. To do. The conduction by the contact does not require joining by an adhesive means such as solder. Moreover, since the upper and lower wirings of the two solar cells are realized only by arranging the wiring structure therebetween, the wiring workability is excellent. The contact state of the conductive portion to the solar battery cell having the above configuration has a high degree of freedom compared to a fixing method such as solder bonding, and thus has excellent impact resistance. Further, in this embodiment, since the first resin layer 50 and the second resin layer 60 are adhesive layers having adhesiveness, the conductive portion 30 partially disposed in the first region 10 and the second region 12. It adheres to the

solar cells

110a and 110b through (specifically, the conductive wire 40). Therefore, a separate bonding means such as a conductive adhesive is not necessary, and the wiring workability is excellent also in this respect.

The solar cell group (wiring solar cell group) 120 to which the wiring structure 1 is attached as described above is sandwiched between two sheet-like sealing resins 150, and the surface covering member 160 and By disposing the back surface covering member 170, the solar cell module 100 in which a plurality of

solar cells

110a, 110b, 110c, and 110d are built in a state where they are conducted is constructed. Note that the two sheet-like sealing resins 150 are sandwiched between the front surface covering member 160 and the back surface covering member 170, and after being attached with a frame (not shown), they are integrated by heat curing and shown in FIG. The sealing resin 150 is obtained. In the solar cell module 100 obtained in this way, the sealing resin 150 is provided between the front surface covering member 160 constituting the front (front) surface of the solar cell module 100 and the rear surface covering member 170 constituting the back surface. The solar cell group (wiring solar cell group) 120 to which the wiring structure 1 is attached is housed in a state covered with the solar cell. In this embodiment, crystalline Si cells (approximately 15.5 cm × 15.5 cm) are used as the

solar cells

110a, 110b, 110c, and 110d, and an ethylene-vinyl acetate copolymer (EVA) is used as the sealing resin 150. ), A glass plate having a thickness of 3.2 mm is used as the surface covering member 160, and a commercially available back sheet is used as the back surface covering member 170.

The structure of the solar cell module 100 will be further described. As described above, the solar cell module 100 includes a plurality of solar cells including the

solar cells

110a, 110b, 110c, and 110d, a sealing resin 150 that covers (surrounds) the solar cells, and a sealing resin. The front surface covering member 160 and the back surface covering member 170 are disposed so as to sandwich the surface 150. A plurality of solar cells including the

solar cells

110a, 110b, 110c, and 110d are arranged in a straight line at a predetermined interval to constitute a solar cell group. An n-type electrode (front electrode) is partially formed on the upper surface (front surface) of

solar cells

110a, 110b, 110c, and 110d, and a p-type electrode (rear surface) is formed on the lower surface (back surface). Electrode). In addition, the upper and lower sides of the solar battery cell in this specification correspond to the front and back of the solar battery cell, and thus correspond to the front and back (upper and lower) of the solar battery module. The surface of the solar cell module is a light incident surface. Depending on how the solar cell module is installed, the top and bottom may not necessarily be strictly up and down, so the top and bottom of the solar cells are not limited to exact top and bottom, and are understood to indicate relative positional relationships. The

In the solar cell group, two adjacent solar cells (for example, the solar cell 110a and the solar cell 110b) are electrically connected by one conductive portion 30. The conductive portion 30 is extended from the upper surface of the solar battery cell 110a to the lower surface of the solar battery cell 110b. More specifically, one conductive portion 30 is disposed on the upper surface of the solar battery cell 110a above the solar battery group, and passes through the space between the solar battery cell 110a and the solar battery cell 110b. It moves below the solar cell group and is disposed on the lower surface of the solar cell 110b. The conductive portion 30 extends from the end of the solar cell 110a (the end opposite to the solar cell 110b side) to the end of the solar cell 110b (the end opposite to the solar cell 110a side), It contacts (specifically, contacts) the upper surface of the solar battery cell 110a and the lower surface of the solar battery cell 110b. Thus, since the electroconductive part 30 is one member and continues from the upper surface of the solar cell 110a to the lower surface of the solar cell 110b, the connection reliability is high and the durability is also excellent.

In this embodiment, one conductive portion 30 is composed of a plurality of conductive wires 40 extending from the upper surface of the solar battery cell 110a to the lower surface of the solar battery cell 110b as described above. The plurality of conductive lines 40 extend along the arrangement direction of the

solar cells

110a and 110b, and are arranged at intervals. These conductive wires 40 are arranged in a straight line so as to be parallel to each other. In the arrangement direction of the

solar cells

110a and 110b, substantially both ends of the

solar cells

110a and 110b (ends of the solar cells 110a (solar cells) 110b (the end opposite to the 110b side)) to the end of the solar battery cell 110b (the end opposite to the solar battery 110a side).

In the solar cell module 100, the first resin layer 50 is disposed above the solar cell group. Specifically, one first resin layer 50 is disposed only above one solar battery cell 110a and is not disposed above another solar battery cell (for example, solar battery cell 110b). Different first resin layers 50 are disposed above other solar cells (for example, solar cells 110b). Moreover, the 1st resin layer 50 is arrange | positioned upwards rather than the electroconductive part 30 located above the photovoltaic cell 110a. In other words, the conductive part 30 is disposed between the solar battery cell 110 a and the first resin layer 50. The first resin layer 50 has substantially the same shape and size as the solar battery cell 110a, and does not protrude from the upper surface of the solar battery cell 110a. The first resin layer 50 of this embodiment has a substantially square shape (specifically, a substantially square shape having a size of approximately 15.5 cm × 15.5 cm).

The first resin layer 50 is a transparent resin layer, and at least the surface on the solar cell side has adhesiveness. The first resin layer 50 in this embodiment is a transparent pressure-sensitive adhesive layer. The first resin layer 50 is in contact with the upper surface of the solar battery cell 110 a from above the conductive part 30 in the non-existing region of the conductive part 30. Specifically, the first resin layer 50 is bonded to the upper surface of the solar battery cell 110 a through the conductive portion 30 from the space between the plurality of conductive wires 40 as the conductive portion 30. That is, the lower surface (surface on the solar cell side) of the first resin layer 50 is bonded to the conductive portion 30 (specifically, the plurality of conductive wires 40) and is not bonded to the conductive portion 30. It adheres to the upper surface of the solar battery cell 110a. As a result, the conductive portion 30 is reliably and stably brought into contact (specifically, contacted) with the upper surface of the solar battery cell 110a.

On the other hand, the second resin layer 60 is disposed below the solar cell group in the solar cell module 100. Specifically, one second resin layer 60 is disposed only below one solar battery cell 110b, and is disposed below other solar battery cells (for example,

solar battery cells

110a and 110c). Absent. Different second resin layers 60 are arranged below other solar cells (for example,

solar cells

110a and 110c). Moreover, the 2nd resin layer 60 is arrange | positioned below the electroconductive part 30 located under the photovoltaic cell 110b. In other words, the conductive part 30 is disposed between the solar battery cell 110 b and the second resin layer 60. The second resin layer 60 has substantially the same shape and size as the solar battery cell 110b, and does not protrude from the lower surface of the solar battery cell 110b. The second resin layer 60 of this embodiment has a substantially square shape (specifically, a substantially square shape having a size of approximately 15.5 cm × 15.5 cm).

The second resin layer 60 has at least a solar cell side surface having adhesiveness. The second resin layer 60 is a transparent adhesive layer in this embodiment. The second resin layer 60 is in contact with the lower surface of the solar battery cell 110 b from below the conductive part 30 in the non-existing region of the conductive part 30. Specifically, the second resin layer 60 is bonded to the lower surface of the solar battery cell 110 b through the conductive portion 30 from the space between the plurality of conductive wires 40 as the conductive portion 30. That is, the upper surface (surface on the solar cell side) of the second resin layer 60 is bonded to the conductive portion 30 (specifically, the plurality of conductive wires 40) and is not bonded to the conductive portion 30. It is bonded to the lower surface of the solar battery cell 110b. As a result, the conductive portion 30 is reliably and stably brought into contact with the lower surface of the solar battery cell 110b.

The above configuration will be described in terms of a cross-sectional structure as follows. That is, in the arrangement | positioning location of the photovoltaic cell 110a, the solar cell module 100 is the surface coating member 160 / sealing resin 150 / first resin layer 50 / conductive part (surface side conductive part) 30 / solar battery cell from upper direction. 110a / conductive portion (back side conductive portion) 30 / second resin layer 60 / sealing resin 150 / back surface covering member 170 has a cross-sectional structure laminated in this order. Moreover, in the arrangement | positioning location of the photovoltaic cell 110b, the solar cell module 100 is the surface coating member 160 / sealing resin 150 / first resin layer 50 / conductive part (surface side conductive part) 30 / solar battery cell from upper direction. 110b / conductive portion (back side conductive portion) 30 / second resin layer 60 / sealing resin 150 / back surface covering member 170 has a cross-sectional structure laminated in this order. The conductive part (front surface side conductive part) 30 disposed on the front surface side of the solar battery cell 110a and the conductive part (back surface side conductive part) 30 disposed on the back surface side of the solar battery cell 110a are separate members. is there. In addition, the conductive part (front surface side conductive part) 30 disposed on the front surface side of the solar battery cell 110b and the conductive part (back surface side conductive part) 30 disposed on the back surface side of the solar battery cell 110b are also separated separate members. It is. However, the front surface side conductive portion 30 in the solar battery cell 110a and the back surface side conductive portion 30 in the solar battery cell 110b are one continuous member. Further, between the

solar cells

110a and 110b, the solar cell module 100 has a surface covering member 160 / sealing resin 150 / conductive portion 30 / sealing resin 150 / back surface covering member 170 stacked in this order from above. Having a cross-sectional structure.

As described above, the

solar cells

110a and 110b and the configuration relating to the electrical connection thereof have been described. Since the above configuration is repeated, a duplicate description is omitted. In addition, the conductive part (more specifically, the conductive wire) disposed on the upper surface or the lower surface of the solar cells located at both ends of the solar cell group is not an electrical connection between the solar cells, but an extraction electrode (not shown) Connected to (terminal bar). Moreover, the solar cell module 100 having the above-described configuration can be preferably manufactured using the wiring structure 1, but is not limited thereto. They can also be produced by placing them at appropriate locations in the module.

According to the above configuration, the wiring connection reliability is high and excellent durability is realized as described above, but EVA is used as the sealing resin, and acrylic is used as the first and second resin layers. When a resin layer is employed, further advantages can be obtained. Specifically, when the sealing resin has a composition that releases an acid or an alkali, the acid or alkali can corrode the solar battery cell, and the power generation efficiency of the solar battery module can be lowered over time. For example, when EVA is used as the sealing resin, acetic acid is gradually released from the EVA to corrode the electrode on the surface of the solar battery cell, and the power generation efficiency may decrease with time. However, in the above configuration, since the first or second resin layer is disposed between the EVA as the sealing resin and the solar battery cell, the acetic acid derived from EVA is converted into the solar battery by the interposition of this resin layer. Contact with the cell is prevented. As a result, the power generation efficiency of the solar cell module is favorably maintained over a long period. The solar cell module having such a configuration can be more durable.

In addition, since the solar cell module configured as described above does not require soldering for wiring, problems due to soldering (typically cell warpage or cracking, characteristic deterioration, flux contamination) are avoided. Is possible. The solderless solar cell module not only can avoid the above-mentioned flux contamination, but can also solve problems such as leaching and cratering caused by solder joints. In addition, the fact that the solder joint is not required brings an advantage to the structure of the solar battery cell. Specifically, an aluminum-containing electrode (typically an electrode made of aluminum, typically an aluminum electrode) is provided on the entire back surface of the cell as a back electrode from the viewpoint of a BSF (Back Surface Field) effect or the like. It is preferable to provide. However, since aluminum is inferior in solder jointability, an electrode (silver-containing electrode) containing silver, which is excellent in solder jointability, as a main component is usually disposed at a joint location with a metal wiring. That is, as the back electrode of the solar battery cell, an aluminum-containing electrode and a silver-containing electrode are usually used in combination. According to the technology disclosed herein, the electrical connection on the back surface of the solar battery cell is realized simply by contacting the back surface electrode (aluminum-containing electrode) on the back surface with the conductive portion. Solder bonding is not necessary. Therefore, by adopting the technique disclosed herein, a solar battery module including a solar battery cell whose back electrode substantially does not contain silver can be realized. This configuration has significant advantages in cost reduction and productivity improvement.

(Second Embodiment)
FIG. 6 is an enlarged top view showing a part of the surface of the solar battery cell according to the second embodiment. FIG. 7 is an enlarged exploded perspective view for explaining the positional relationship between the surface electrode and the conductive wire of the solar battery cell according to the second embodiment. FIG. 8 is a diagram for explaining the arrangement relationship between the surface electrode and the conductive wire of the solar battery cell according to the second embodiment, and schematically showing the contact state between the conductive wire and the surface electrode. It is sectional drawing.

The solar cell module 200 according to the second embodiment has basically the same configuration as the first embodiment except that the pattern of the surface electrode 212 of the solar cell 210 is different. Therefore, about this embodiment, it demonstrates centering on the surface electrode 212 of the photovoltaic cell 210, and abbreviate | omits description about another point. Note that the conductive wire 240 in FIG. 6 is shown by a broken line and is transmitted for convenience of explanation.

As shown in FIGS. 6 to 8, the solar cell 210 constituting the solar cell module 200 is provided with an electrode (surface electrode) 212 on the surface thereof. The electrode 212 includes a plurality of first linear portions 214 extending linearly and a plurality of second linear portions 216 extending linearly so as to intersect the first linear portions 214. Specifically, the first linear portion 214 and the second linear portion 216 are both portions that extend linearly. Each of the plurality of first linear portions 214 is spaced from the adjacent first linear portion 214. More specifically, each of the plurality of first linear portions 214 includes They are arranged in parallel at intervals. Similarly, each of the plurality of second linear portions 216 is spaced from the adjacent second linear portion 216, and more specifically, the plurality of second linear portions 216. Are arranged in parallel at intervals. In this embodiment, the first linear portion 214 and the second linear portion 216 are substantially orthogonal. As a result, the electrode 212 has a lattice pattern in which the first linear portion 214 forms a horizontal line and the second linear portion 216 forms a vertical line when viewed from above in FIG.

A conductive wire 240 is disposed on each of the plurality of first linear portions 214. The conductive wire 240 is a conductive member extending in a line extending from the upper surface of the solar battery cell 210 to the lower surface of a solar battery cell (not shown) located adjacent to the solar battery cell 210. Between the upper and lower wiring (electrical connection) is made. This point is as described above. The conductive line 240 overlaps the first linear portion 214 so that the longitudinal direction thereof coincides with the longitudinal direction of the first linear portion 214, whereby the electrode 212 and the conductive line 240 are linearly formed. Abuts continuously. It can be said that the first linear portion 214 is a conductive wire contact portion. Further, the width of the first linear portion 214 is smaller than the width of the conductive line 240. Therefore, the conductive wire 240 covers the first linear portion 214 on the surface of the solar battery cell 210.

In this embodiment, the width of the first linear portion 214 is approximately 40 to 80 μm, and the width of the conductive wire 240 is approximately 0.8 mm, but is not limited thereto. The ratio (Wc / W1) of the width Wc of the conductive wire 240 to the width W1 of the first linear portion 214 is preferably larger than 1, more preferably 2 or more, from the viewpoint of reducing shadow loss and electrode material. More preferably 5 or more (for example, 8 or more, typically 10 or more). In addition, from the viewpoint of improving the conduction reliability between the electrode 212 and the conductive wire 240 and improving the current collection efficiency, the ratio (Wc / W1) is preferably 160 or less, more preferably 50 or less, and even more preferably 30 or less (for example, 15 Hereinafter, typically 12 or less). The specific value of the width W1 of the first linear portion 214 is preferably 1 mm or less, more preferably 800 μm or less, and even more preferably 500 μm or less (for example, 300 μm or less). By using the wiring by physical contact, sufficient conduction (high current collection efficiency, conduction reliability) can be obtained even if the first linear portion 214 is narrow. In addition, from the viewpoint of preventing disconnection and improving conduction reliability, the width W1 is preferably 5 μm or more, more preferably 10 μm or more (typically 30 μm or more, for example, 40 μm or more).

From the viewpoint of electrode formability, the ratio (W1 _max / W1 _min ) of the minimum value W1 _min and the maximum value W1 _max of the width W1 of the first linear portion 214 is preferably 200 or less, more preferably. Is set to 100 or less, more preferably 50 or less. In a preferred embodiment, the ratio (W1 _max / W1 _min ) is 20 or less, more preferably 10 or less, still more preferably 2 or less (for example, 1.5 or less, typically 1.2 or less). The first linear portion 214 formed in a straight line having a substantially constant width is easy to be formed by various methods (for example, a screen printing method), and disconnection at the minimum width portion is less likely to occur. Can be reliable. The lower limit of the ratio (W1 _max / W1 _min ) is 1 in principle. Regarding the width of the second linear portion 216, it is preferable that the relationship between the minimum value and the maximum value of the width in the first linear portion 214 is satisfied from the same viewpoint.

The film thickness (height) T1 of the first linear portion 214 is an aspect ratio (T1 / W1) represented by the ratio between the film thickness T1 of the first linear portion 214 and the width W1 from the viewpoint of direct resistance reduction. ) Is preferably 1/200 or more, more preferably 1/100 or more. In a preferred embodiment, the aspect ratio (T1 / W1) is 1/50 or more, more preferably 1/10 or more (typically 1/5 or more, for example, 1/3 or more). Further, from the viewpoint of electrode formability, the aspect ratio (T1 / W1) may be less than 2 (for example, less than 1, typically 1/2 or less). The film thickness T1 of the first linear portion 214 can be adjusted by selecting an electrode forming method, overcoating (typically, the number of printings), and the like.

In this embodiment, the distance between the first linear portions 214 and the distance between the conductive lines 240 are both about 2 cm, but are not limited thereto. The interval between the first linear portions 214 is basically the same as the interval between the conductive lines 240, and the number thereof is the same as the number of the conductive lines 240. The plurality of first linear portions 214 and the plurality of conductive lines 240 may be set so that the corresponding ones overlap each other. Thereby, conduction reliability and current collection efficiency are improved. The interval between the first linear portions 214 is preferably 0.1 cm or more, more preferably 0.8 cm or more, and further preferably 1.5 cm or more. The interval is suitably less than 6 cm, preferably less than 4.0 cm, more preferably less than 3.0 cm, and even more preferably 2.8 cm or less. In addition, the said space | interval is a pitch and points out the distance between the centerlines in the width direction of the 1st linear part 214. FIG. The same applies to the interval between second linear portions described later.

Further, in this embodiment, the width of the second linear portion 216 is about 40 to 80 μm as in the case of the first linear portion 214, but is not limited to this. The ratio (W1 / W2) between the width W1 of the first linear portion 214 and the width W2 of the second linear portion 216 is preferably about 0.1 or more, more preferably 0, from the viewpoint of electrode formability. .15 or more, more preferably 0.2 or more (for example, 0.25 or more, typically 0.5 or more), and from the same viewpoint, preferably about 10 or less, more preferably 6 or less, still more preferably Is 5 or less (for example, 4 or less, typically 2 or less). When the surface electrode 212 of the solar battery cell 210 is formed by a single printing by a method such as a screen printing method, the ratio (W1 / W2) is from the viewpoint of forming a highly accurate electrode with high productivity. A range of 0.8 to 1.2 is particularly preferable. The specific value of the width W2 of the second linear portion 216 is preferably 1 mm or less, more preferably 800 μm or less, and even more preferably 500 μm or less (for example, 300 μm or less) from the viewpoint of reducing shadow loss. From the viewpoint of preventing disconnection and reducing series resistance, the width W2 is preferably 5 μm or more, more preferably 10 μm or more (typically 30 μm or more, for example, 40 μm or more).

In this embodiment, the interval (pitch) between the second linear portions 216 is in the range of about 1.3 to 2.2 mm, but the interval is not limited to the current collection efficiency ( What is necessary is just to set suitably in consideration of a shadow loss and the short circuit current (Jsc), and it is not limited to said value. For example, the interval between the second linear portions 216 is approximately 0.1 mm or more (for example, 0.5 mm or more, typically 1 mm or more) from the viewpoint of reducing shadow loss. From the viewpoint of short circuit current (Jsc) reduction and reliability, it is about 10 mm or less (for example, 5 mm or less, typically 3 mm or less).

Similarly to the film thickness T1 of the first linear portion 214, the film thickness (height) T2 of the second linear portion 216 is also the film thickness T2 of the second linear portion 216 from the viewpoint of direct resistance reduction. The aspect ratio (T2 / W2) represented by the ratio of the width W2 is preferably 1/200 or more, more preferably 1/100 or more. In a preferred embodiment, the aspect ratio (T2 / W2) is 1/50 or more, more preferably 1/10 or more (typically 1/5 or more, for example, 1/3 or more). From the viewpoint of electrode formability, the aspect ratio (T2 / W2) may be less than 2 (for example, less than 1, typically ½ or less). The film thickness T2 of the second linear portion 216 can be adjusted by selecting an electrode formation method, overcoating (typically, the number of printings), and the like.

The film thickness T1 of the first linear portion 214 and the film thickness T2 of the second linear portion 216 are such that their ratio (T1 / T2) is from the viewpoint of electrode formation and contact with the conductive wire 240. It is appropriate to set it to 2 or less (for example, 1.5 or less, typically 1.2 or less). In a preferred embodiment, the above (T1 / T2) is approximately 1. In other words, it is preferable that the upper surface of the first linear portion 214 and the upper surface of the second linear portion 216 are formed substantially flush with each other. Such an electrode 212 tends to obtain a contact area with the conductive wire 240 and tends to have excellent conduction reliability. When the film thickness T1 of the first linear portion 214 and the film thickness T2 of the second linear portion 216 are different, the above (T1 / T2) from the viewpoint of conduction reliability with the conductive wire 240. Is preferably larger than 1 (for example, 1.1 or more, further 1.2 or more).

The electrode 212 as described above can be formed using a conventionally known method, and the formation method is not particularly limited. For example, using a screen printing method, a stencil printing method, a dispenser method (inkjet method), a plating method, etc., the electrode forming material is formed on the surface of the solar cell substrate (more specifically, on the surface of the solar cell substrate). It is possible to form the electrode 212 having the pattern as in the above embodiment by applying to the surface of the antireflection film. Of these, screen printing is preferable. As a screen printing plate, a mesh plate is preferably used. When screen printing is employed, any of multiple printing such as single printing, dual printing, and double printing may be employed. For example, in a pattern in which the width and film thickness of the first linear portion 214 and the second linear portion 216 are approximated, the electrode 212 can be formed with high accuracy by a single operation by single printing. This is advantageous in that the labor of alignment required for printing a plurality of times can be omitted and the material loss can be reduced. Alternatively, when it is desired to make the width, film thickness, material, and the like of the first linear portion 214 and the second linear portion 216 different, dual printing or double printing is preferable. For example, double printing is suitable for increasing the film thickness of the first linear portion 214 and the second linear portion 216 for the purpose of improving the current collection efficiency. In the case of adopting dual printing, it is preferable to print the second linear portion 216 first and then print the first linear portion 214 from the viewpoint of improving current collection efficiency and conduction reliability. The electrode 212 formed on the antireflection film is then electrically connected to the cell substrate by fire-through during firing.

A conventionally well-known thing can also be used also about an electrode formation material, It is not limited to a specific material. The electrode forming material includes a conductive component such as metal (for example, silver, copper, aluminum, etc.) as a main component (a component having the highest blending ratio. For example, a component that can be contained by 70% by weight or more based on solid content. Is included. Preferable examples include conductive paste containing a metal powder such as silver or aluminum as a main component, and metal plating such as copper. For example, for a solar cell represented by a Si cell (more specifically, an antireflection film made of silicon nitride or silicon oxide formed on the surface of a solar cell substrate), a conductive powder is used as a main component. A conductive paste containing an inorganic material such as glass frit or an organic vehicle is preferably used. Preferable examples of the conductive powder include metal powders such as silver and aluminum. Preferred examples of the glass frit include, but are not limited to, PbO. In consideration of environmental load, lead-free B ₂ O ₃ , SiO ₂ , Bi ₂ O ₃ , MgO, CaO, SrO, BaO , Li ₂ O, Na ₂ O, K ₂ O, TiO ₂ , ZrO ₂ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , CuO, ZnO, GeO ₂ , Al ₂ O ₃ , P ₂ O ₅ Among them, one having two or more appropriate softening points may be selected and used. As the organic vehicle, a binder and an organic solvent are used. Examples of the binder include cellulosic resins (methylcellulose, ethylcellulose, nitrocellulose, etc.), acrylic resins, and alkyd resins. As the organic solvent, various organic solvents such as texanol and xylene can be used without limitation. By adding and mixing these components so as to have desired conductivity and viscosity, a conductive paste is produced. In addition, the conductive paste may contain various additives known or commonly used in this field as necessary.

The configuration of the upper surface (front surface) of the solar battery cell 210 has been described above, but the technology disclosed herein can also be applied to the lower surface (back surface) of the solar battery cell 210. Such a configuration is preferably applied to, for example, a double-sided light receiving solar cell. The details in that case are basically the same as those of the upper surface of the solar battery cell 210, and therefore, redundant description is omitted here. In addition, the lower surface (back surface) of the solar battery cell 210 is not limited to the above configuration, and can be the same as a conventionally known configuration. For example, the structure which provided the electrode (for example, combined use of an aluminum containing electrode and a silver containing electrode) was provided in the whole back surface of the photovoltaic cell. Alternatively, as described above, a configuration including only an aluminum-containing electrode without using a silver-containing electrode as a back electrode (typically, a configuration in which the entire back surface of a solar battery cell is covered with an aluminum electrode) is used. Is also possible.

Note that the conductive portion is not limited to the shape, structure, and the like of the above embodiment. When a wiring structure is applied to a solar cell module, various shapes, structures, and the like that can realize electrical connection of solar cells using a conductive portion can be employed. The conductive portion of the above embodiment is a plurality of conductive lines that extend linearly and are arranged in parallel to each other, but the conductive lines may extend in a curved shape. In the case of having a plurality of conductive lines, the plurality of conductive lines may be separated from each other, connected, or non-parallel to each other (for example, may be crossed or non-parallel so as not to contact each other). ). When the conductive portion is composed of conductive lines, the number of conductive lines in the wiring structure is 2 or more (typically 2 to 20, more preferably 4 to 12, more preferably 6 to 10). It is preferable, or it may be one.

In addition, since the conductive portion in the second region is disposed on the back surface side of the solar battery cell, it may not have a thin line shape such as a conductive wire. You may have. In other words, the conductive portion of the first region located on the front (front) surface side of one solar cell is defined as a conductive wire (for example, copper wire), and the first region located on the back surface side of the other solar cell. The conductive portion in the two regions may be a conductive sheet having substantially the same shape as the second region (for example, a metal sheet such as a rectangular copper foil). In this case, the conductive portion has a shape in which a stripe-shaped portion made of a conductive line and a quadrangular portion are continuous.

Moreover, in the said embodiment, although the 1st resin layer and the 2nd resin layer had the square shape of substantially the same shape as a photovoltaic cell, it is not limited to this, The shape of a photovoltaic cell, etc. Various shapes can be taken. The first resin layer and the second resin layer may be made of the same material (same composition) or may be made of different materials (having different compositions). For example, when the solar battery cell is a single-sided light receiving type, only the first resin layer is a transparent resin layer (preferably has a total light transmittance greater than or equal to a predetermined value described later), and the second resin layer is transparent. The non-transparent resin layer which does not have may be sufficient. In that case, the second resin layer specifically has a total light transmittance described below of less than 70% (for example, less than 50%, typically less than 30%). Therefore, the first resin layer and the second resin layer may have different total light transmittance. Or when a photovoltaic cell is a double-sided light reception type, it is preferable that both the 1st resin layer and the 2nd resin layer are transparent resin layers, and it is more preferable to have the total light transmittance more than the predetermined mentioned later. In addition, when the electroconductive part in a 2nd area | region is an electroconductive sheet, the 2nd resin layer does not need to be. The technique disclosed here is not limited to the one including the first resin layer and the second resin layer.

Moreover, when the electrode provided on the surface of the solar battery cell has the first linear portion and the second linear portion as in the second embodiment, the first linear portion is By disposing the conductive line on the first linear part, the desired effect (improvement of current collection efficiency and conduction reliability) is realized Is done. Therefore, the configuration of the electrodes provided on the surface of the solar battery cell is not particularly limited as long as it is. For example, when the surface electrode of the solar battery cell has a first linear portion, the shape, the arrangement relationship, and the number of the first linear portion are the same shape, arrangement relationship, and number as the conductive wire. can do. Accordingly, the first linear portion may extend in a curved shape, and the plurality of first linear portions may be separated from each other, connected, or non-parallel to each other. (For example, non-parallel so as not to contact each other). For example, the first linear portion may have a shape extending in a curved shape while being bent regularly or irregularly on the surface of the solar battery cell. Moreover, the aspect in which a some 1st linear part exhibits a wavy stripe pattern may be sufficient. Examples of the shape extending in a curved shape include curved wave shapes such as a sine wave, pseudo sine wave, and arc wave, and non-curved shapes such as a zigzag shape and a triangular wave. The number of the first linear portions on the solar battery cell is 2 or more (typically 2 to 20, more preferably 4 to 12, more preferably 6 to 6) corresponding to the number of conductive wires. 10). In another aspect, the width of the first linear portion may be thicker than the width of the conductive line overlapping therewith.

In the case where the electrode provided on the surface of the solar battery cell has the first linear portion and the second linear portion, the intersection angle between the first linear portion and the second linear portion is: The angle is not limited to the right angle as in the second embodiment, and a desired angle can be adopted in consideration of current collection efficiency and the like. For example, it is preferable that the first linear portion and the second linear portion usually intersect so that the acute angle side is 45 ° or more (typically 70 ° or more and 90 ° or less). Moreover, when the surface electrode of a photovoltaic cell has a 1st linear part, the width | variety of a 1st linear part may not be constant but may change. For example, the portion that intersects the second linear portion may be configured to have a large width (for example, a dot shape larger than the other portions), and the width of the first linear portion is regular or irregular. It may change to. For example, the width may gradually or suddenly become thicker or thinner. Further, one of the first linear portions may be partially divided into two, for example, by providing an electrode non-forming portion in a part thereof. As described above, when the width of the first linear portion is not constant, the average value of the widths at a plurality of arbitrary positions is adopted as the width value of the first linear portion. Similarly to the first linear portion, the second linear portion can be configured as described above.

In addition, the solar cells arranged in one solar cell module are usually 5 or more (for example, 10 or more, typically 30 or more), and typically 50 or more (50 to 70). . The number of wiring structures per row composed of a plurality of solar cells is basically a number obtained by subtracting 1 from the number of solar cells. In the solar cells located at both ends of the solar cell group, conductive portions connected to extraction electrodes (terminal bars) (not shown) can be arranged on the front surface or the back surface. Moreover, in the said embodiment, although the several photovoltaic cell was comprised as a photovoltaic cell group arranged in a line, the arrangement | sequence (arrangement | positioning) of a several photovoltaic cell is not limited to this, A linear form, a curve It may be a pattern, a regular pattern, or an irregular pattern. Moreover, the space | interval of a photovoltaic cell does not need to be constant.

≪Components of wiring structure and solar cell module≫
The conductive portion, the first resin layer, and the second resin layer that constitute the wiring structure are not limited to those of the above-described embodiment, and various modifications can be made within a range in which the effects of the invention are exhibited. The same applies to the components of the solar cell module. Hereinafter, each element which comprises a wiring structure and a solar cell module is demonstrated.

<Conductive part>
The conductive portion (including a conductive line, the same applies hereinafter) typically includes a conductive material. As a material constituting the conductive portion, a metal material such as gold, silver, copper, aluminum, iron, nickel, tin, chromium, bismuth, indium, zinc, or an alloy thereof can be preferably used. Among these, silver, copper, aluminum, and iron are more preferable, and copper and aluminum are more preferable. Conductive paths composed essentially of metal have the advantage of lower resistance. As a typical example, there is a conductive portion made of a conductive wire made of a metal wire. As the metal wire, those having a tensile strength measured according to JIS Z 2241: 2011 of 200 N / mm ² or more are preferably used from the viewpoint of strength, handling property, and the like. As a specific example, a copper metal wire is preferably used. Especially, the metal wire by which plating, such as tin (Sn), silver (Ag), nickel (Ni), was given as a coating | coated part using a copper metal wire as a core material is more preferable. The film thickness (for example, plating thickness) of the covering portion may be about 10 μm or less (for example, 5 μm or less, and further, for example, 3 μm or less). The film thickness is suitably about 0.1 μm or more (for example, 0.5 μm or more). From the viewpoint of improving the diffuse reflectance, it is preferably 1.0 μm or more, more preferably 1.5 μm or more (for example, 2 μm). Further, for example, 3 μm or more). As a method for forming the covering portion, a conventionally known method such as a clad method can be adopted in addition to the above-described plating method. In another aspect, a conductive wire (typically a metal wire) subjected to rust prevention treatment is preferably used as the conductive portion.

The part located in the second region of the conductive part may be a conductive sheet. The conductive sheet is typically a metal sheet (for example, a metal foil). As said metal sheet, what gave at least 1 sort (s) of surface treatment of a roughening process, a rust prevention process, and an adhesive improvement process is used preferably. Suitable examples of the metal sheet include copper foil (in particular, electrolytic copper foil). When the conductive part in the first region is a conductive line and the conductive part in the second region is a conductive sheet, the conductive part is produced by fixing the conductive line and the conductive sheet. As a method for fixing the conductive wire and the conductive sheet, it is preferable to employ welding. As the welding method, conventionally known various types of welding can be employed. For example, arc welding, resistance welding, laser beam welding, electron beam welding, and ultrasonic welding are preferably employed. Or it is also possible to employ | adopt the fixing method by plating joining and a conductive adhesive.

When the conductive part has a combined shape of, for example, a conductive wire and a conductive sheet, the conductive part may be formed from a patterned metal sheet. Such a conductive part can be formed by etching a metal sheet. Specifically, a resist is attached to the surface of a metal sheet (typically a metal foil), and a predetermined resist pattern is formed by applying a photolithography technique. Next, the metal sheet is patterned using a known or conventional etching solution. In this way, the conductive portion is formed. A similar configuration can be obtained by various vapor deposition methods.

Alternatively, the conductive portion may be formed, for example, by applying a conductive paste as a conductive material. As the conductive paste, conductive components made of metal materials such as gold, silver, copper, aluminum, iron, nickel, tin, chromium, bismuth, indium, and alloys thereof, and conductive components made of non-metals such as carbon (hereinafter referred to as “conductive paste”) The same)) and a resin component such as polyester or epoxy resin can be used in a suitable solvent. Especially, it is preferable to use silver or copper as a conductive component from a viewpoint of temporal stability. Specific examples of the conductive paste include silver paste (trade name “Pertron K-3105”, manufactured by Pernox, conductive component: Ag, resin component: polyester resin, specific resistance: 6.5 × 10 ⁻⁵ Ω · cm) Is mentioned. The specific resistance of the conductive paste at 25 ° C. is about 5 × 10 ⁻⁴ Ω · cm or less (for example, 1 × 10 ⁻⁴ Ω · cm or less, typically 5.0 × 10 ⁻⁷ Ω · m or less). Preferably there is. The specific resistance of the conductive component constituting the conductive paste is preferably 5.0 × 10 ⁻⁷ Ω · m or less. The conductive portion can be formed by applying a conductive paste to the surface of a resin layer, a peelable support or the like using a known dispenser.

In a preferred embodiment, the surface of the conductive portion (at least the surface on the solar cell module incident surface side. Typically, the surface layer portion, for example, the portion having a depth of 1 μm or less from the surface of the conductive portion, the same applies hereinafter) is made of silver. As such a conductive part, a metal material (for example, copper wire) subjected to silver plating can be used. When the surface of the conductive part is made of silver, the purity of silver on the surface (for example, the purity of silver plating) is not particularly limited, and is suitably about 95% by weight (for example, 99% by weight or more). It is. The silver purity is preferably 99.7% by weight or more, more preferably 99.9% by weight or more. Thus, by disposing high-purity silver on the surface of the conductive portion, the diffuse reflectance is increased and the power generation efficiency is improved. The concentration of the additive component (component other than silver, such as selenium and antimony) on the surface of the conductive portion is preferably about 0.3% by weight or less (preferably 0.1% by weight or less). The purity of silver and the concentration of components other than silver can be measured using an inductively coupled plasma mass spectrometer (ICP-MS) and an inductively coupled plasma emission spectrometer (ICP-AES). The same method can be adopted in the embodiments described later.

In another preferred embodiment, the conductive portion is formed by hot-melt coating a metal material (typically an alloy) having a low melting point (for example, a melting point of 300 ° C. or lower, preferably 250 ° C. or lower). Specifically, a low melting point alloy (for example, “SnBi solder” manufactured by Arakawa Chemical Industry Co., Ltd.), 139 ° C.) can be applied to form the conductive portion. Note that the same configuration as described above can be obtained by employing various printing methods such as screen printing.

The arithmetic average roughness (Ra) of the surface of the conductive part is preferably 60 nm or more. This tends to increase the diffuse reflectance and improve the power generation efficiency. The Ra is more preferably 70 nm or more, further preferably 80 nm or more (for example, 110 nm or more, further for example, 140 nm or more), and particularly preferably 200 nm or more (for example, 220 nm or more, further, for example, 250 nm or more). In particular, the surface of the conductive portion is composed of silver (typically a silver plating layer), the purity thereof is 99.7% by weight or more (preferably 99.9% by weight or more), and the film thickness of silver By applying Ra in the above-mentioned range to a configuration in which is 1.0 μm or more (preferably 1.5 μm or more), the diffuse reflectance can be significantly improved. The Ra can be adjusted by selecting a metal material type on the surface of the conductive portion, roughening using an embossing roll, or surface treatment such as etching.

The above Ra is measured by the following method. First, a shape profile is measured for the surface of the conductive portion using an optical interference type shape measuring device. The measurement range is about 600 μm × 450 μm. As the optical interference type shape measuring device, an optical interference type shape measuring device manufactured by Veeco, model “Wyko NT9100” or its equivalent may be used. After removing the waviness included in the obtained measurement result by Gaussian processing, Ra of the surface of the conductive portion is calculated. When the conductive part is composed of a plurality of (for example, three or more) conductive wires, Ra is calculated by the above method for any three of the conductive parts, and the value obtained by arithmetically averaging them is defined as Ra on the surface of the conductive part. It is preferable to adopt. In the examples described later, the same method is used.

The surface of the conductive part preferably exhibits a diffuse reflectance of about 60% or more. Thereby, power generation efficiency can be improved. Here, the diffuse reflectance refers to the diffuse reflectance with respect to light having a wavelength of 550 nm (the ratio (%) of diffuse reflection with respect to incident light). The diffuse reflectance is more preferably 80% or more, further preferably 85% or more, particularly preferably 87% or more, and particularly preferably 90% or more.

The ratio of diffuse reflection to the total reflection on the surface of the conductive portion (diffuse reflection ratio) is preferably about 80% or more. Specifically, the diffuse reflection ratio refers to the ratio (%) of diffuse reflection in total reflection (the sum of regular reflection (also referred to as specular reflection) and diffuse reflection) with respect to light having a wavelength of 550 nm. The diffuse reflection ratio is more preferably 90% or more, further preferably 95% or more, and particularly preferably 99% or more.

The above diffuse reflectance and diffuse reflectance ratio can be measured using a commercially available spectrophotometer. For example, an integrating sphere unit manufactured by JASCO (for example, product name “ISV-722”), a spectrophotometer manufactured by the same (for example, product name “V-660”), and a standard white plate manufactured by Labsphere (for example, Spectralon ( (Registered trademark) 6916-H422A). The measurement is performed on the portion of the conductive portion that is the surface on the light incident surface side of the solar cell module. Moreover, when the irradiation area of the electroconductive part (for example, conductive wire) which is a measuring object is inadequate, it shall measure by arranging a several electroconductive part closely. In the examples described later, the same method is used.

The ratio of the height (H) to the width (W) (H / W) in the cross section orthogonal to the longitudinal direction of the conductive portion (typically conductive wire) is set to be ½ or less. preferable. Thereby, excellent performance can be exhibited. The ratio (H / W) is preferably about 1/3 or less from the viewpoint of wiring workability and connection reliability, and preferably 1/5 or more (for example, 1/4 or more) from the viewpoint of power generation efficiency. It is. Moreover, when a conductive part has a conductive wire, the conductive wire has a rectangular shape in a cross section orthogonal to the longitudinal direction. Thereby, almost the whole area of one surface of the conductive wire can be in surface contact with the surface of the solar battery cell. The rectangular shape may be chamfered at each corner. The cross-sectional shape of the conductive wire is not limited to this, and may be a circular shape, an elliptical shape, a semicircular shape, a trapezoidal shape, a triangular shape, or the like. From the viewpoint of the contact area with the solar battery cell, it is preferable that the conductive portion (typically conductive wire) has a flat portion (typically a surface) in contact with the solar battery cell.

When the conductive part has a conductive line, the width of the conductive line (in the case of having a plurality of conductive lines, each width) is preferably 0.03 mm or more from the viewpoint of reduction of current collection loss, strength, handling properties, and workability. More preferably, it is 0.1 mm or more, More preferably, it is 0.2 mm or more. The width is preferably 1.5 mm or less, more preferably 1.2 mm or less, and further preferably 1.0 mm or less from the viewpoint of reducing shadow loss. In addition, the said width | variety points out the length (width) orthogonal to the longitudinal direction of a conductive wire.

In addition, when arranging a plurality of conductive lines extending in a line at intervals, the distance between the conductive lines is preferably 0.1 cm or more, more preferably 0.8 cm or more, from the viewpoint of reducing shadow loss. More preferably 1.5 cm or more. The distance is preferably less than 4.0 cm, more preferably less than 3.0 cm, and even more preferably 2.8 cm or less (for example, 2.5 cm or less) from the viewpoint of reducing current collection loss. In addition, the said space | interval is a pitch and points out the distance between the centerlines in the width direction of a conductive wire.

The thickness (height) of the conductive portion is 0.01 to 1 mm (for example, 0.02 to 0.5 mm, typically 0.05 to 0.00 mm) from the viewpoints of conductivity, strength, handling properties, and workability. 3 mm) or so is preferable. The thickness of the conductive wire is also preferably selected from the same range.

<First resin layer and second resin layer>
(Resin layer characteristics)
The first resin layer and the second resin layer (hereinafter collectively referred to as “resin layer”) disclosed herein can function as layers that favorably maintain the contact state between the solar battery cell and the conductive portion. Typically, the resin layer is preferably a layer that exhibits the properties of an elastic body or a viscoelastic body in a temperature range near room temperature. The viscoelastic body referred to here is a material having both properties of viscosity and elasticity, that is, a material having a property that satisfies the phase of the complex elastic modulus exceeding 0 and less than π / 2 (typically at 25 ° C. A material having the above properties). The resin layer is preferably insulative.

The storage elastic modulus G ′ (frequency 1 Hz, strain 0.1%, 150 ° C.) of the resin layer disclosed herein is preferably 5,000 Pa or more. By using a resin layer exhibiting a storage elastic modulus G ′ of a predetermined value or higher at high temperature, the solar cell and the conductive part are in good contact under high temperature conditions, and under various conditions (for example, wide temperature conditions), The contact state can be stably maintained. The resin layer more preferably satisfies tan δ described later in addition to the storage elastic modulus G ′. For example, when the conductive part is pressed against the solar battery cell from the outside of the resin layer when constructing the solar battery module, the conductive part can be brought into good contact with the surface of the solar battery cell even under high temperature conditions. The 150 ° C. storage elastic modulus G ′ is more preferably 10,000 Pa or more, further preferably 20,000 Pa or more, particularly preferably 25,000 Pa or more (for example, 50,000 Pa or more, typically 80,000 Pa or more). is there. The 150 ° C. storage elastic modulus G ′ is usually 1,000,000 Pa or less, preferably 500,000 Pa or less, more preferably 200,000 Pa or less (for example, 150,000 Pa or less, typically 100,000 or less). 000 Pa or less).

The storage elastic modulus G ′ (frequency 1 Hz, strain 0.1%) of the resin layer is preferably in the range of 5,000 Pa to 1,000,000 Pa in the temperature range of 80 ° C. to 150 ° C. That the change in the storage elastic modulus G ′ in the high temperature range is within a predetermined range may mean that the physical properties of the resin layer are not easily affected by the temperature change. The storage elastic modulus G ′ of the resin layer in the temperature range of 80 ° C. to 150 ° C. is more preferably 5,000 Pa to 500,000 Pa, still more preferably 5,000 Pa to 200,000 Pa (for example, 10,000 Pa to 100,000 Pa). Is within the range.

Furthermore, the storage elastic modulus G ′ (frequency 1 Hz, strain 0.1%) of the resin layer is preferably in the range of 5,000 Pa to 10,000,000 Pa in the temperature range of 30 ° C. to 150 ° C. The change in the storage elastic modulus G ′ within the wide temperature range as described above being within a predetermined range may mean that the physical properties of the resin layer are not easily affected by the temperature change. The storage elastic modulus G ′ of the resin layer in the temperature range of 30 ° C. to 150 ° C. is more preferably 5,000 Pa to 1,000,000 Pa, still more preferably 5,000 Pa to 500,000 Pa (for example, 10,000 Pa to 200, 000 Pa).

Also, the maximum value of tan δ of the resin layer disclosed herein is preferably less than 0.4 in the temperature range of 80 ° C. to 150 ° C. By using a resin layer having a tan δ of a predetermined value or less in a high temperature region, the solar battery cell and the conductive part are in good contact in the high temperature region, and the contact state is various under various conditions (for example, a wide temperature condition). It can be stably maintained. For example, when the conductive part is pressed against the solar battery cell from the outside of the resin layer when constructing the solar battery module, the conductive part can be brought into good contact with the surface of the solar battery cell even under high temperature conditions. Here, tan δ is a value (G ″ / G ′) obtained from loss elastic modulus G ″ / storage elastic modulus G ′. The maximum value of tan δ of the resin layer in the temperature range of 80 ° C. to 150 ° C. is more preferably less than 0.3. In addition, the minimum value of tan δ in the above temperature range can be usually 0.01 or more (for example, 0.1 or more).

The storage elastic modulus G ′ (frequency 1 Hz, strain 0.1%, 150 ° C.) and tan δ (G ″ / G ′) and tan δ (G ″ / G ′) of the resin layer are commercially available rheometers (for example, device name “ARES 2KFRT”, TA Instruments). Measured by a specified temperature range (a temperature range including 80 ° C to 150 ° C, and a temperature range including 30 ° C to 150 ° C) under the conditions of a frequency of 1 Hz and a strain of 0.1%. Good. What is necessary is just to set a measurement temperature range and a temperature increase rate appropriately according to the model etc. of a measuring apparatus. For example, a temperature range of 30 ° C. to 160 ° C. and a temperature increase rate of about 0.5 ° C. to 20 ° C./min (for example, 10 ° C./min) can be achieved. As a measurement sample, it is desirable to use a resin layer having a thickness of about 2 mm punched out to a diameter of about 8 mm.

The resin layer may or may not have adhesiveness (typically adhesiveness). In other words, the resin layer may be an adhesive layer or a non-adhesive layer. Here, the “adhesive layer” refers to a SUS304 stainless steel plate as an adherend in accordance with JIS Z 0237: 2009, and a 2 kg roller is reciprocated once in a measurement environment at 23 ° C. to be bonded to the adherend. 30 minutes later, the peel strength when peeled in the direction of 180 ° at a pulling speed of 300 mm / min is 0.1 N / 20 mm or more. The “non-adhesive layer” refers to a layer that does not correspond to the adhesive layer, and typically refers to a layer having a peel strength of less than 0.1 N / 20 mm. The layer that does not stick to the stainless steel plate when the 2 kg roller is reciprocated once in a measurement environment of 23 ° C. and pressed against the SUS304 stainless steel plate is a non-adhesive layer here. This is a typical example included in the concept.

The technique disclosed here is preferably implemented in a form including a resin layer corresponding to an adhesive layer (also referred to as an adhesive layer) formed from an adhesive. In this case, the resin layer forming composition may be a pressure-sensitive adhesive composition. In the present specification, the “pressure-sensitive adhesive” refers to a material that exhibits a soft solid (viscoelastic body) state in a temperature range near room temperature and has a property of easily adhering to an adherend by pressure. The adhesive here is generally complex elastic modulus E ^* (1 Hz) as defined in “C. A. Dahlquist,“ Adhesion: Fundamental and Practice ”, McLaren & Sons, (1966) P. 143”. <10 < ⁷ > dyne / cm < ² > material (typically a material having the above properties at 25 [deg.] C.).

It is preferable that the surface of the resin layer has adhesiveness. As a result, the conductive portion is satisfactorily fixed to the resin layer. Moreover, the conductive part non-arrangement region on the surface of the resin layer adheres well to the solar battery cell when the solar battery module is constructed. By using a resin layer having adhesiveness on both surfaces, the sealing resin and the conductive portion can be fixed satisfactorily. In addition, when the surface of the resin layer is weakly adhesive or substantially non-adhesive, the conductive portion and the solar battery cell may be fixed to the resin layer using a known adhesive, pressure-sensitive adhesive, or the like. .

In a preferred embodiment, the surface of the resin layer exhibits a 180-degree peel strength (adhesive power to solar cell) of 3N / 10 mm or more with respect to the crystalline Si solar cell. From the viewpoint of fixing to the solar battery cell or the conductive part, the adhesive strength to the solar battery cell is more preferably 5 N / 10 mm or more, further preferably 8 N / 10 mm or more (for example, 10 N / 10 mm or more, typically 12 N). / 10 mm or more). In a particularly preferred embodiment, the surface of the resin layer exhibits a 180-degree peel strength of 15 N / 10 mm or more with respect to the crystalline Si solar battery cell. The upper limit of the adhesive strength to the solar cell on the surface of the resin layer is not particularly limited, and the above adhesive strength is usually 50 N / 10 mm or less (for example, 30 N / 10 mm or less, typically from the viewpoint of workability such as reattachment). 20N / 10 mm or less).

The adherend used for the measurement of the adhesion to solar cells is a crystalline Si solar cell. For example, a crystalline Si solar battery cell manufactured by Q CELLS, a single crystalline Si cell manufactured by GINTECH, or a polycrystalline Si cell is preferably used. For measurement, after the resin layer is firmly bonded to the adherend by laminating or the like, using a commercially available tensile tester (for example, “Autograph AGS-J”, manufactured by Shimadzu Corporation) at 23 ° C., 50 It can be carried out in an atmosphere of% RH under the conditions of a tensile speed of 30 mm / min and a peeling angle of 180 degrees.

The resin layer typically has translucency. The resin layer which concerns on a preferable one aspect | mode is a transparent resin layer (for example, transparent adhesive layer). In this specification, the transparent resin layer refers to a resin layer having a total light transmittance of 70% or more. From the viewpoint of power generation efficiency of the solar battery cell, the total light transmittance of the resin layer is more preferably 85% or more, and further preferably 90% or more. The total light transmittance of the resin layer can be measured using a commercially available haze meter (for example, trade name “HR-100”, manufactured by Murakami Color Research Laboratory Co., Ltd.).

The resin layer disclosed herein is preferably composed of a resin material having a melt mass flow rate (MFR) at 150 ° C. of 9 g / 10 min or less. The resin layer exhibiting the MFR can exhibit good shape stability. The MFR is more preferably 3 g / 10 min or less, further preferably 1 g / 10 min or less, and particularly preferably 0.5 g / 10 min or less (for example, 0.2 g / 10 min or less). The above MFR measurement is based on JIS K 7210: 1999 or ASTM D 1238, and the amount of resin flowing out at a constant time under conditions of a temperature of 190 ° C. and a load of 2.16 Kg is weighed with a balance and unit time (10 minutes) This may be done by calculating the amount of resin discharged.

The linear expansion coefficient of the resin layer is preferably less than 15% in the temperature range of −40 ° C. to 85 ° C. According to the resin layer exhibiting the above linear expansion coefficient, a wiring with further improved durability is realized. The linear expansion coefficient is more preferably 12% or less (for example, 10% or less). As the linear expansion coefficient of the resin layer, either one (preferably both) values of the tensile mode and the compression mode measured by the following method are adopted.
[Linear expansion coefficient]
(Tensile mode)
Each resin layer is cut into a size of 10 mm in length × about 0.5 mm ² in cross-sectional area to produce a test piece. Using this test piece, a line at −40 ° C. to 85 ° C. under the conditions of a tensile load of 20 mN and a temperature increase rate of 1.7 ° C./min using a thermal analyzer (trade name “EXSTAR6000”, manufactured by Seiko Instruments Inc.) The expansion rate (%) is measured. The linear expansion coefficient is obtained from the following equation.
Linear expansion coefficient (%) at −40 ° C. to 85 ° C. = (AB) / B × 100
A: Maximum length of test piece at −40 ° C. to 85 ° C. (mm)
B: Minimum value of length of test piece at −40 ° C. to 85 ° C. (mm)
(Compression mode)
Each resin layer is cut into a size of about 5 mm square to produce a test piece. Using this test piece, a linear expansion coefficient (%) at −40 ° C. to 85 ° C. under the following conditions using a TMA (Thermal Mechanical Analysis) device (device name “TMA / SS7100”, manufactured by SII Nano Technology) Measure. The linear expansion coefficient is obtained from the following equation.
Linear expansion coefficient (%) at −40 ° C. to 85 ° C. = (AB) / B × 100
A: Maximum thickness of test piece at −40 ° C. to 85 ° C. (μm)
B: Minimum thickness of specimen at -40 ° C to 85 ° C (μm)
Measurement condition:
Load during indentation test: 9.8 mN
Probe diameter: φ3.5mm
Temperature program; −60 ° C. → 160 ° C., 10 ° C./min Measurement atmosphere; N ₂ (flow rate 200 mL / min)

(Composition of resin layer)
The resin layer disclosed here is a resin layer formed from a resin material. A resin layer containing a crosslinked resin as a base polymer (for example, a resin layer subjected to crosslinking treatment) is preferable. The resin layer has physical properties different from those of the sealing resin, and can typically be formed from a resin material different from the resin material of the sealing resin. The resin that forms the resin layer is an acrylic resin, EVA resin, polyolefin resin, rubber, silicone resin, polyester resin, urethane resin, polyether resin, polyamide resin, fluorine resin, etc. 1 type or 2 types or more selected from these resin. The acrylic resin is an acrylic polymer as a base polymer (the main component of the polymer component, that is, the component having the largest blending ratio in the polymer component, typically a component that exceeds 50% by weight). The resin material. The same meaning applies to EVA and other resins.

(EVA resin)
The resin layer according to a preferred embodiment is an EVA resin layer formed from an EVA resin. The proportion of EVA in the resin layer (which may also be a resin layer forming composition) is not particularly limited and is typically 50% by weight or more, preferably 70% by weight or more, more preferably 80% by weight. That's it. The EVA resin layer is subjected to a thermosetting treatment at about 80 to 200 ° C. (eg, 100 to 180 ° C., typically 120 to 160 ° C.) from the viewpoint of obtaining desired physical properties. Is preferred. The heat curing treatment time is not particularly limited and is usually 5 minutes or longer, preferably 10 minutes or longer, more preferably 20 minutes or longer (for example, 30 minutes or longer, typically 40 minutes to 120 minutes). The EVA resin layer is preferably subjected to a press treatment before or during the thermosetting treatment.

(Acrylic polymer)
In a preferred embodiment, the resin layer may be a layer containing an acrylic polymer as a base polymer, that is, an acrylic resin layer. A resin layer having such a composition is preferable because it can be easily adjusted to desired physical properties such as shape stability and flexibility. The proportion of the acrylic polymer in the resin layer is not particularly limited, and is typically 50% by weight or more, preferably 70% by weight or more, and more preferably 80% by weight or more.
In the present specification, “(meth) acrylate” means acrylate and methacrylate comprehensively. Similarly, “(meth) acryloyl” means acryloyl and methacryloyl, and “(meth) acryl” generically means acrylic and methacryl.
Further, in this specification, the “monomer component constituting the acrylic polymer” refers to a monomer unit constituting the acrylic polymer in the resin material forming the resin layer. The monomer component may be contained in the resin layer forming composition used for forming the resin layer in an unpolymerized form (that is, in the form of a raw material monomer in which the polymerizable functional group is unreacted). , May be included in the form of a polymer, or may be included in both forms.

The resin layer forming composition disclosed herein preferably contains the component (A) as a monomer component constituting the acrylic polymer.

The component (A) is an alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms at the ester end. Hereinafter, an alkyl (meth) acrylate having an alkyl group having a carbon number of X or more and Y or less at the ester end may be referred to as “C _XY alkyl (meth) acrylate”. The structure of the C _1-20 alkyl group in the C _1-20 alkyl (meth) acrylate is not particularly limited, and either a linear or branched alkyl group can be used. As the component (A), one kind of such C _1-20 alkyl (meth) acrylate can be used alone or in combination of two or more kinds.

_{Examples of} C _1-20 alkyl (meth) acrylates having a linear alkyl group at the ester end include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, n- Pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, n-decyl (meth) acrylate, n-undecyl (Meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, n-pentadecyl (meth) acrylate, n-hexadecyl (meth) acrylate, n-heptadecyl (meta) ) Acrylate, n- Examples include octadecyl (meth) acrylate, n-nonadecyl (meth) acrylate, and n-eicosyl (meth) acrylate. Further, as C _3-20 alkyl (meth) acrylate having a branched alkyl group at the ester terminal, isopropyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, isopentyl (meth) acrylate, t- Pentyl (meth) acrylate, neopentyl (meth) acrylate, isohexyl (meth) acrylate, isoheptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, isodecyl (meth) Acrylate, 2-propylheptyl (meth) acrylate, isoundecyl (meth) acrylate, isododecyl (meth) acrylate, isotridecyl (meth) acrylate, isomistyryl (meth) Examples include acrylate, isopentadecyl (meth) acrylate, isohexadecyl (meth) acrylate, isoheptadecyl (meth) acrylate, isostearyl (meth) acrylate, isononadecyl (meth) acrylate, and isoeicosyl (meth) acrylate. These alkyl (meth) acrylates can be used alone or in combination of two or more.

The component (A) can be preferably implemented in an embodiment containing C _4-9 alkyl (meth) acrylate as the component (A1). When the acrylic polymer contains the component (A1) as a monomer unit, a resin layer having desired physical properties tends to be easily obtained, and tackiness tends to be easily obtained. The component (A1) may be one or more selected from C _4-9 alkyl (meth) acrylates. From the viewpoint of compatibility with other monomer components (for example, cyclic nitrogen-containing monomers), C _4-9 alkyl acrylate is preferably used as component (A1). Preferable examples of C _4-9 alkyl acrylate include n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate and isononyl acrylate.

When the component (A) includes the component (A1), the proportion of the component (A1) in the component (A) is usually 20% by weight or more (eg 20 to 80% by weight), preferably 30% by weight or more. (For example, 30 to 70% by weight), more preferably 40% by weight or more (for example, 40 to 60% by weight). The proportion of the component (A1) in the component (A) may be 50% by weight or more (for example, 80% by weight or more, typically 90 to 100% by weight).

Further, the embodiment in which the component (A) includes C _10-18 alkyl (meth) acrylate as the component (A2) can be preferably carried out. When the acrylic polymer contains the component (A2) as a monomer unit, a resin layer having desired physical properties tends to be more easily obtained. The component (A2) may be one or more selected from C _10-18 alkyl (meth) acrylates. The component (A2) preferably contains a C _10-18 alkyl (meth) acrylate in which the alkyl group is a branched chain, and more preferably from the viewpoint of compatibility with other monomer components (for example, a cyclic nitrogen-containing monomer). From _C10-18 alkyl acrylates in which the alkyl group is branched. Preferable examples of the C _10-18 alkyl (meth) acrylate include isodecyl acrylate, isodecyl methacrylate, dodecyl methacrylate, tridecyl methacrylate, isomistyryl acrylate, isostearyl acrylate and stearyl methacrylate.

When the component (A) includes the component (A2), the proportion of the component (A2) in the component (A) is usually 20% by weight or more (for example, 20 to 80% by weight), preferably 30% by weight or more. (For example, 30 to 70% by weight), more preferably 40% by weight or more (for example, 40 to 60% by weight). The proportion of the component (A2) in the component (A) may be 50% by weight or more (for example, 80% by weight or more, typically 90 to 100% by weight).

When the component (A1) and the component (A2) are used in combination as the component (A), the weight ratio (A1: A2) between the component (A1) and the component (A2) is not particularly limited, and is usually 1: The ratio is suitably 9 to 9: 1, and preferably 2: 8 to 8: 2 (eg, 3: 7 to 7: 3, typically 4: 6 to 6: 4).

The component (A) may contain one or more of C _1-3 alkyl (meth) acrylate and C _19-20 alkyl (meth) acrylate as the component (A3). When the component (A) includes the component (A3), from the viewpoint of the physical properties of the resin layer, the proportion of the component (A3) in the component (A) is usually 30% by weight or less (for example, 15% by weight or less, typically 1 to 5% by weight) is preferable. The technique disclosed here is an embodiment in which the component (A) does not substantially contain the component (A3) (the proportion of the component (A3) in the component (A) is less than 1% by weight, and further 0.1% by weight. In an embodiment that is less than).

The proportion of the component (A) in the monomer component is not particularly limited. From the viewpoint of physical properties of the resin layer and adhesive properties such as adhesive strength, the proportion of the component (A) is usually suitably 30% by weight or more, preferably 50% by weight or more, more preferably 60%. % By weight or more (eg, 75% by weight or more). In addition, the upper limit of the proportion of the component (A) is suitably about 98% by weight or less from the viewpoint of sufficiently obtaining the effects of the later-described components (B) and (C), and is 95% by weight. It is preferable that the amount be less than or equal to (for example, 90% by weight or less, typically 85% by weight or less).

In a preferred embodiment, the resin layer forming composition contains a component (B) as a monomer component constituting the acrylic polymer. The component (B) is a heterocycle-containing monomer such as a cyclic nitrogen-containing monomer or a cyclic ether group-containing monomer. The component (B) can advantageously contribute to improving the shape stability and transparency of the resin layer. The heterocyclic ring-containing monomer can be used alone or in combination of two or more.

As the cyclic nitrogen-containing monomer, those having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a cyclic nitrogen structure can be used without particular limitation. The cyclic nitrogen structure preferably has a nitrogen atom in the cyclic structure. Examples of cyclic nitrogen-containing monomers include lactam vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2- Oxazoline group-containing monomers such as oxazoline and 2-isopropenyl-2-oxazoline; vinyl-based compounds having nitrogen-containing heterocycles such as vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, and vinylmorpholine And monomers. Moreover, the (meth) acryl monomer containing nitrogen-containing heterocyclic rings, such as a morpholine ring, a piperidine ring, a pyrrolidine ring, a piperazine ring, an aziridine ring, is mentioned. Specific examples include N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine, N-acryloylaziridine and the like. Among the cyclic nitrogen-containing monomers, lactam vinyl monomers are preferable and N-vinylpyrrolidone is more preferable from the viewpoint of cohesiveness and the like.

As the monomer having a cyclic ether group, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and a cyclic ether group such as an epoxy group or an oxetane group. It can be used without particular limitation. Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, and the like. Examples of the oxetane group-containing monomer include 3-oxetanylmethyl (meth) acrylate, 3-methyl-oxetanylmethyl (meth) acrylate, 3-ethyl-oxetanylmethyl (meth) acrylate, and 3-butyl-oxetanylmethyl (meth) acrylate. , 3-hexyl-oxetanylmethyl (meth) acrylate, and the like.

From the viewpoint of the physical properties of the resin layer, the proportion of the component (B) in the monomer component is usually 0.5% by weight or more, preferably 1% by weight or more, more preferably 3% by weight. More preferably, it is 10% by weight or more (for example, 12% by weight or more). The proportion of the component (B) is suitably about 50% by weight or less, preferably 40% by weight or less (for example, 30% by weight or less), from the viewpoint of sufficiently obtaining the effect of containing the component (A). , Typically 25% by weight or less).

In a preferred embodiment, the resin layer forming composition includes a component (C) as a monomer component constituting the acrylic polymer. The component (C) is a monomer having at least one of a hydroxy group and a carboxy group.

As the hydroxy group-containing monomer, those having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a hydroxy group can be used without particular limitation. Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl ( Hydroxyalkyl (meth) acrylates such as (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate; -Hydroxyalkylcycloalkane (meth) acrylates such as -hydroxymethylcyclohexyl) methyl (meth) acrylate. Other examples include hydroxyethyl (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, and the like. These can be used alone or in combination of two or more. Of these, hydroxyalkyl (meth) acrylate is preferred. For example, a hydroxyalkyl (meth) acrylate having a hydroxyalkyl group having 2 to 6 carbon atoms can be preferably used. Of these, 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are more preferable.

As the carboxy group-containing monomer, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a carboxy group can be used without particular limitation. Examples of carboxy group-containing monomers include ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate; itaconic acid, maleic acid, fumaric acid, And ethylenically unsaturated dicarboxylic acids such as citraconic acid; metal salts thereof (for example, alkali metal salts); anhydrides of the above ethylenically unsaturated dicarboxylic acids such as maleic anhydride and itaconic anhydride. These can be used alone or in combination of two or more. Among these, acrylic acid and methacrylic acid are preferable.

The technique disclosed herein can be preferably implemented in a mode in which the component (C) includes a hydroxy group-containing monomer. That is, it is preferable that the component (C) includes only a hydroxy group-containing monomer or includes a hydroxy group-containing monomer and a carboxy group-containing monomer. By increasing the proportion of the hydroxy group-containing monomer in the component (C), metal corrosion caused by the carboxy group can be reduced. From this, the technique disclosed here can be preferably implemented in a mode in which the monomer component does not substantially contain a carboxy group-containing monomer. For example, the proportion of the carboxy group-containing monomer in the monomer component can be less than 1% by weight, preferably less than 0.5% by weight, more preferably less than 0.2% by weight.

The proportion of the component (C) in the monomer component is usually suitably 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 0, from the viewpoint of the physical properties of the resin layer. .8% by weight or more. The proportion of the component (C) may be 3% by weight or more, or 5% by weight or more (for example, 8% by weight or more, typically 10% by weight or more). The proportion of the component (C) is suitably about 35% by weight or less, preferably 30% by weight or less, more preferably 25% by weight or less (typically 5% by weight or less, eg 3 % By weight or less).

In a particularly preferred embodiment, the monomer component constituting the acrylic polymer includes all the components (A), (B), and (C). In that case, when the total amount of the above components (A), (B) and (C) is 100% by weight, the proportion of component (A) is 50 to 99% by weight (more preferably 60 to 95% by weight, still more preferably Is preferably 70 to 85% by weight, and the proportion of component (B) is 0.9 to 49.9% by weight (more preferably 4.5 to 39.5% by weight, still more preferably 14.2 to 29.2% by weight), and the proportion of component (C) is 0.1 to 35% by weight (more preferably 0.5 to 30% by weight, still more preferably 0.8 to 25% by weight). It is preferable to do.

The constituent monomer component in the technique disclosed herein may contain a monomer other than the components (A), (B) and (C) (hereinafter also referred to as “optional monomer”) as necessary.

Examples of the optional monomer include monomers containing a functional group other than a hydroxy group and a carboxy group. Such a functional group-containing monomer can be used for the purpose of introducing a crosslinking point into the acrylic polymer or increasing the cohesive strength of the acrylic polymer. Examples of the functional group-containing monomer include amide group-containing monomers such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide, and N-methylol (meth) acrylamide; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; For example, sulfonic acid group-containing monomers such as styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid; for example, phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; Keto group-containing monomers such as acrylamide, diacetone (meth) acrylate, vinyl methyl ketone, vinyl acetoacetate; for example, isocyanate group-containing monomers such as 2- (meth) acryloyloxyethyl isocyanate; For example, alkoxy group-containing monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; for example, alkoxysilyl groups such as 3- (meth) acryloxypropyltrimethoxysilane and 3- (meth) acryloxypropyltriethoxysilane Containing monomer; and the like. These can be used alone or in combination of two or more.

Other examples of the optional monomer include alicyclic monomers. As the alicyclic monomer, those having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having an alicyclic structure-containing group can be used without particular limitation. it can. Here, the “alicyclic structure-containing group” refers to a portion containing at least one alicyclic structure. The “alicyclic structure” refers to a saturated or unsaturated carbocyclic structure having no aromaticity. In the present specification, the alicyclic structure-containing group is sometimes simply referred to as “alicyclic group”. Preferable examples of the alicyclic group include a hydrocarbon group and a hydrocarbon oxy group containing an alicyclic structure.

Examples of preferred alicyclic monomers include alicyclic (meth) acrylates having an alicyclic group and a (meth) acryloyl group. Specific examples of the alicyclic (meth) acrylate include cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, and cyclooctyl (meth). Examples include acrylate, isobornyl (meth) acrylate, and dicyclopentanyl (meth) acrylate. These can be used alone or in combination of two or more.

The monomer component in the technology disclosed herein can be copolymerized with the above components (A), (B), and (C) as the above arbitrary monomer for the purpose of adjusting Tg of acrylic polymer and improving cohesion. In addition, a copolymerizable monomer other than those exemplified above may be included. Examples of such copolymerizable monomers include carboxylic acid vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene, substituted styrene (α-methylstyrene, etc.), vinyltoluene; ) Aromatic ring-containing acrylate (eg phenyl (meth) acrylate), aryloxyalkyl (meth) acrylate (eg phenoxyethyl (meth) acrylate), arylalkyl (meth) acrylate (eg benzyl (meth) acrylate) ( (Meth) acrylates; olefinic monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene; chlorine-containing monomers such as vinyl chloride and vinylidene chloride; for example, methyl vinyl ether, ethyl vinyl ether, and the like Vinyl ether monomers; other, macromonomers, and the like having a radical polymerizable vinyl group in the monomer ends obtained by polymerizing a vinyl group. These can be used alone or in combination of two or more.

The amount of these optional monomers used is not particularly limited and can be determined as appropriate. Usually, the total amount of the arbitrary monomers used is suitably less than 50% by weight of the monomer component, preferably 30% by weight or less, and more preferably 20% by weight or less. The technique disclosed here can be preferably implemented in an embodiment in which the total amount of any monomer used is 10% by weight or less (for example, 5% by weight or less) of the monomer component. The technique disclosed here is an embodiment in which an optional monomer is not substantially used (for example, an embodiment in which the amount of the optional monomer used is 0.3% by weight or less, typically 0.1% by weight or less) of the monomer component. However, it can be preferably implemented.

The above-described component (A), component (B), component (C) and optional monomer are typically monofunctional monomers. In addition to such a monofunctional monomer, the monomer component in the technique disclosed herein can contain a polyfunctional monomer as necessary for the purpose of adjusting the cohesive force of the resin layer. Here, the monofunctional monomer in this specification refers to a monomer having one polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group, and a polyfunctional monomer. As described later, refers to a monomer having at least two polymerizable functional groups.

The polyfunctional monomer is a monomer having at least two polymerizable functional groups having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group. Examples of polyfunctional monomers include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, penta Erythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2-ethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methanetri (meth) ) Of acrylate, esters of polyhydric alcohols and (meth) acrylic acid; allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate. A polyfunctional monomer can be used individually by 1 type or in combination of 2 or more types. Among these, trimethylolpropane tri (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and dipentaerythritol hexa (meth) acrylate can be preferably used. From the viewpoint of reactivity and the like, a polyfunctional monomer having two or more acryloyl groups is usually preferable.

The amount of the polyfunctional monomer used varies depending on the molecular weight, the number of functional groups, and the like, but is preferably 3% by weight or less of the above monomer component from the viewpoint of balancing cohesion and adhesion in a balanced manner. Is more preferable, and 1% by weight or less (for example, 0.5% by weight or less) is more preferable. Moreover, the lower limit of the usage-amount in the case of using a polyfunctional monomer should just be larger than 0 weight%, and is not specifically limited. Usually, the effect of improving the cohesive force can be appropriately exhibited by setting the amount of the polyfunctional monomer used to 0.001% by weight or more (for example, 0.01% by weight or more) of the monomer component.

Although not particularly limited, the proportion of the total amount of the component (A), the component (B) and the component (C) in the monomer component is typically more than 50% by weight, preferably 70% by weight. Above, more preferably 80% by weight or more, still more preferably 90% by weight or more. The technique disclosed here can be preferably implemented in an embodiment in which the ratio of the total amount is 95% by weight or more (for example, 99% by weight or more). The technology disclosed herein can be preferably implemented in an embodiment in which the ratio of the total amount in the monomer components is 99.999% by weight or less (for example, 99.99% by weight or less).

Although not particularly limited, the Tg of the polymer corresponding to the composition of the monomer component is preferably −20 ° C. or less, preferably −25 ° C. or less, from the viewpoints of physical properties and adhesiveness of the resin layer. More preferably -80 ° C or higher, preferably -60 ° C or higher, -50 ° C or higher (eg -40 ° C or higher, typically -35 ° C or higher). It is more preferable.

Here, the Tg of the polymer corresponding to the composition of the monomer component refers to the Fox based on the Tg of the homopolymer of each monomer contained in the monomer component and the weight fraction of the monomer. The value calculated from the formula. The formula of Fox is a relational expression between Tg of a copolymer and glass transition temperature Tgi of a homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer, as shown below.
1 / Tg = Σ (Wi / Tgi)
In the above Fox equation, Tg is the glass transition temperature (unit: K) of the copolymer, Wi is the weight fraction of monomer i in the copolymer (copolymerization ratio on a weight basis), and Tgi is the monomer i. Represents the glass transition temperature (unit: K) of the homopolymer. However, in this specification, the calculation of Tg is performed considering only the monofunctional monomer. Therefore, when the monomer component includes a polyfunctional monomer, the total amount of the monofunctional monomer contained in the monomer component is defined as 100% by weight, and the Tg of the homopolymer of each monofunctional monomer and the above total amount of the monofunctional monomer Tg is calculated based on the weight fraction relative to.

As the Tg of the homopolymer, the following values are adopted for the monomers shown below.
2-Ethylhexyl acrylate -70 ° C
n-Butyl acrylate -55 ° C
Isostearyl acrylate -18 ℃
Cyclohexyl acrylate 15 ° C
Isobornyl acrylate 94 ° C
N-Vinyl-2-pyrrolidone 54 ° C
2-Hydroxyethyl acrylate -15 ° C
4-hydroxybutyl acrylate -40 ° C
Acrylic acid 106 ℃
For monomers other than those exemplified above, the values described in “Polymer Handbook” (3rd edition, John Wiley & Sons, Inc., 1989) are used as the Tg of the homopolymer. The highest value is adopted for the monomer whose values are described in this document. When not described in the above Polymer Handbook, values obtained by the measurement method described in Japanese Patent Application Publication No. 2007-51271 are used.

(Composition for resin layer formation)
The composition for forming a resin layer disclosed herein includes a monomer component having the above-described composition in the form of a polymer, an unpolymerized product (that is, a form in which the polymerizable functional group is unreacted), or a mixture thereof. Can be included. The composition for forming a resin layer is a composition in which an organic solvent contains a resin layer forming component (for example, an adhesive component) (a composition for forming a solvent type resin layer), and a form in which the resin layer forming component is dispersed in an aqueous solvent. Composition (water-dispersed resin layer forming composition), a composition prepared to cure with active energy rays such as ultraviolet rays and radiation to form a resin layer forming component (active energy ray curable resin layer formation) And a hot melt type resin layer forming composition that forms a resin layer when coated in a heated and melted state and cooled to near room temperature.

The resin layer forming composition typically contains at least part of the monomer components of the composition (may be part of the type of monomer or part of the quantity). In the form of a polymer. The polymerization method for forming the polymer is not particularly limited, and various conventionally known polymerization methods can be appropriately employed. For example, thermal polymerization such as solution polymerization, emulsion polymerization and bulk polymerization (typically performed in the presence of a thermal polymerization initiator); photopolymerization performed by irradiation with light such as ultraviolet rays (typically It is carried out in the presence of a photopolymerization initiator.); Radiation polymerization carried out by irradiation with radiation such as β-rays and γ-rays; Of these, photopolymerization is preferred. In these polymerization methods, the mode of polymerization is not particularly limited, and conventionally known monomer supply methods, polymerization conditions (temperature, time, pressure, light irradiation amount, radiation irradiation amount, etc.), materials used other than monomers (polymerization initiator) , Surfactant, etc.) can be selected as appropriate.

In the polymerization, a known or commonly used photopolymerization initiator or thermal polymerization initiator can be used depending on the polymerization method, polymerization mode, and the like. Such a polymerization initiator can be used individually by 1 type or in combination of 2 or more types as appropriate.

The photopolymerization initiator is not particularly limited. For example, ketal photopolymerization initiator, acetophenone photopolymerization initiator, benzoin ether photopolymerization initiator, acylphosphine oxide photopolymerization initiator, α- Ketol photoinitiator, aromatic sulfonyl chloride photoinitiator, photoactive oxime photoinitiator, benzoin photoinitiator, benzyl photoinitiator, benzophenone photoinitiator, thioxanthone light A polymerization initiator or the like can be used.

Specific examples of the ketal photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one (for example, trade name “Irgacure 651” manufactured by BASF).
Specific examples of the acetophenone photopolymerization initiator include 1-hydroxycyclohexyl-phenyl-ketone (for example, trade name “Irgacure 184” manufactured by BASF), 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (for example, trade name “Irgacure 2959” manufactured by BASF), 2-hydroxy-2 -Methyl-1-phenyl-propan-1-one (for example, trade name “Darocur 1173” manufactured by BASF), methoxyacetophenone and the like are included.
Specific examples of the benzoin ether photopolymerization initiator include benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether and benzoin isobutyl ether, and substituted benzoin ethers such as anisole methyl ether.
Specific examples of the acylphosphine oxide photopolymerization initiator include bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (for example, trade name “Irgacure 819” manufactured by BASF), bis (2,4,6 -Trimethylbenzoyl) -2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (for example, trade name “Lucirin TPO” manufactured by BASF), bis (2,6- Dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and the like.
Specific examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1- [4- (2-hydroxyethyl) phenyl] -2-methylpropan-1-one, and the like. It is. Specific examples of the aromatic sulfonyl chloride photopolymerization initiator include 2-naphthalenesulfonyl chloride and the like. Specific examples of the photoactive oxime photopolymerization initiator include 1-phenyl-1,1-propanedione-2- (o-ethoxycarbonyl) -oxime and the like. Specific examples of the benzoin photopolymerization initiator include benzoin and the like. Specific examples of the benzyl photopolymerization initiator include benzyl and the like.
Specific examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexyl phenyl ketone, and the like.
Specific examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone. 2,4-diisopropylthioxanthone, dodecylthioxanthone and the like.

The thermal polymerization initiator is not particularly limited. For example, an azo polymerization initiator, a peroxide initiator, a redox initiator by a combination of a peroxide and a reducing agent, a substituted ethane initiator. Etc. can be used. More specifically, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (2-amidinopropane)

dihydrochloride

2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis (N, N′-dimethyleneisobutylamidine), 2,2 ′ -Azo initiators such as azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate; persulfates such as potassium persulfate and ammonium persulfate; benzoyl peroxide, t-butyl hydroperoxide Peroxide initiators such as hydrogen peroxide; substituted ethane initiators such as phenyl substituted ethane; persulfates and sulfites Combination of sodium hydrogen, redox initiators such as a combination of a peroxide and sodium ascorbate; but the like, without limitation. The thermal polymerization can be preferably carried out at a temperature of, for example, about 20 to 100 ° C. (typically 40 to 80 ° C.).

The amount of such a thermal polymerization initiator or photopolymerization initiator used can be a normal amount used according to the polymerization method, polymerization mode, etc., and is not particularly limited. For example, a polymerization initiator of 0.001 to 5 parts by weight (typically 0.01 to 2 parts by weight, for example, 0.01 to 1 part by weight) can be used with respect to 100 parts by weight of the monomer component to be polymerized. .

(Composition for forming a resin layer containing a polymerized monomer component and an unpolymerized product)
The resin layer forming composition according to a preferred embodiment includes a polymerization reaction product of a monomer mixture containing at least a part of the monomer component (raw material monomer) of the composition. Typically, a part of the monomer component is included in the form of a polymer, and the remainder is included in the form of an unpolymerized substance (unreacted monomer). The polymerization reaction product of the monomer mixture can be prepared by at least partially polymerizing the monomer mixture.
The polymerization reaction product is preferably a partial polymerization product of the monomer mixture. Such a partial polymer is a mixture of a polymer derived from the monomer mixture and an unreacted monomer, and typically exhibits a syrup shape (viscous liquid). Hereinafter, such a partially polymerized product may be referred to as “monomer syrup” or simply “syrup”.

The polymerization method for obtaining the polymerization reaction product is not particularly limited, and various polymerization methods as described above can be appropriately selected and used. From the viewpoints of efficiency and simplicity, a photopolymerization method can be preferably employed. According to photopolymerization, the polymerization conversion rate of the monomer mixture can be easily controlled by polymerization conditions such as the amount of light irradiation (light quantity).

The polymerization conversion rate (monomer conversion) of the monomer mixture in the partial polymer is not particularly limited. The polymerization conversion rate can be, for example, 70% by weight or less, and preferably 60% by weight or less. From the viewpoint of ease of preparation of the resin layer forming composition containing the partial polymer, coating properties, and the like, usually, the polymerization conversion rate is suitably 50% by weight or less, and 40% by weight or less (for example, 35% by weight). % Or less) is preferable. The lower limit of the polymerization conversion rate is not particularly limited and is typically 1% by weight or more, and usually 5% by weight or more is appropriate.

The resin layer forming composition containing a partial polymer of the monomer mixture can be easily obtained by, for example, partially polymerizing a monomer mixture containing all of the raw material monomers by an appropriate polymerization method (for example, photopolymerization method). . The resin layer forming composition containing the partial polymer may contain other components used as necessary (for example, a photopolymerization initiator, a polyfunctional monomer, a crosslinking agent, an acrylic oligomer described later, and the like). . The method of blending such other components is not particularly limited, and for example, it may be previously contained in the monomer mixture or added to the partial polymer.

Further, in the resin layer forming composition disclosed herein, a complete polymerization product of a monomer mixture containing some types of monomers among the monomer components (raw material monomers) is converted into the remaining types of monomers or partial polymerization products thereof. It may be in a dissolved form. Such a resin layer forming composition is also included in examples of the resin layer forming composition containing a polymerized monomer component and an unpolymerized product. In the present specification, the “completely polymerized product” means that the polymerization conversion rate is more than 95% by weight.

As described above, a photopolymerization method can be preferably employed as a curing method (polymerization method) when forming a resin layer from a resin layer forming composition containing a polymerized monomer component and an unpolymerized product. In the resin layer forming composition containing the polymerization reaction product prepared by the photopolymerization method, it is particularly preferable to employ the photopolymerization method as the curing method. Since the polymerization reaction product obtained by the photopolymerization method already contains a photopolymerization initiator, when the resin layer forming composition containing this polymerization reaction product is further cured to form a resin layer, a new photopolymerization start is started. It can be photocured without adding an agent. Or the composition for resin layer formation of the composition which added the photoinitiator as needed to the polymerization reaction material prepared by the photopolymerization method may be sufficient. The photopolymerization initiator to be added may be the same as or different from the photopolymerization initiator used for the preparation of the polymerization reaction product. The resin layer forming composition prepared by a method other than photopolymerization can be made photocurable by adding a photopolymerization initiator. The photocurable resin layer forming composition has an advantage that even a thick resin layer can be easily formed. In a preferred embodiment, the photopolymerization when forming the resin layer from the resin layer forming composition can be performed by ultraviolet irradiation. A known high-pressure mercury lamp, low-pressure mercury lamp, metal halide lamp, or the like can be used for ultraviolet irradiation.

(Composition for forming a resin layer containing a monomer component in the form of a completely polymerized product)
The resin layer forming composition according to another preferred embodiment includes the monomer component of the composition in the form of a completely polymerized product. Such a resin layer forming composition is, for example, a solvent-type resin layer forming composition containing an acrylic polymer, which is a complete polymer of monomer components, in an organic solvent, water in which the acrylic polymer is dispersed in an aqueous solvent. It may be in the form of a dispersion type resin layer forming composition.

((Meth) acrylic oligomer)
The composition for forming a resin layer disclosed herein may contain a (meth) acrylic oligomer from the viewpoint of improving adhesive strength. By including a (meth) acrylic oligomer, the adhesive force of the resin layer can be improved.

The (meth) acrylic oligomer preferably has a Tg of about 0 ° C. or higher and 300 ° C. or lower, preferably about 20 ° C. or higher and 300 ° C. or lower, more preferably about 40 ° C. or higher and 300 ° C. or lower. When Tg is within the above range, the adhesive force can be preferably improved. Note that the Tg of the (meth) acrylic oligomer is a value calculated based on the Fox equation, similar to the Tg of the acrylic polymer.

The weight average molecular weight (Mw) of the (meth) acrylic oligomer may typically be 1000 or more and less than 30000, preferably 1500 or more and less than 20000, and more preferably 2000 or more and less than 10,000. It is preferable for Mw to be within the above range because good adhesive force and holding characteristics can be obtained. Mw of the (meth) acrylic oligomer is measured by GPC and can be obtained as a standard polystyrene equivalent value. Specifically, it is measured on a “HPLC 8020” manufactured by Tosoh Corporation using two TSKgelGMH-H (20) columns as a column and a tetrahydrofuran solvent at a flow rate of about 0.5 mL / min.

As a monomer constituting the (meth) acrylic oligomer, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octyl ( (Meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl Alkyl (meth) acrylates such as meth) acrylate, dodecyl (meth) acrylate; (meth) acrylic acid and alicyclic such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate Examples include esters with alcohols; aryl (meth) acrylates such as phenyl (meth) acrylate and benzyl (meth) acrylate; (meth) acrylates obtained from terpene compound derivative alcohols; and the like. Such (meth) acrylate can be used individually by 1 type or in combination of 2 or more types.

Examples of (meth) acrylic oligomers include alkyl (meth) acrylates in which alkyl groups such as isobutyl (meth) acrylate and t-butyl (meth) acrylate have a branched structure; cyclohexyl (meth) acrylate and isobornyl (meth) acrylate, Esters of (meth) acrylic acid and alicyclic alcohols such as dicyclopentanyl (meth) acrylate; cyclic structures such as aryl (meth) acrylates such as phenyl (meth) acrylate and benzyl (meth) acrylate It is preferable that an acrylic monomer having a relatively bulky structure typified by (meth) acrylate is included as a monomer unit from the viewpoint of further improving adhesiveness. In addition, when ultraviolet rays are used in the synthesis of a (meth) acrylic oligomer or in the production of a resin layer, those having a saturated bond are preferred in that polymerization inhibition is unlikely to occur, and the alkyl group has a branched structure. An alkyl (meth) acrylate having an ester or an ester with an alicyclic alcohol can be preferably used as a monomer constituting the (meth) acrylic oligomer.

From this point, suitable (meth) acrylic oligomers include, for example, dicyclopentanyl methacrylate (DCPMA), cyclohexyl methacrylate (CHMA), isobornyl methacrylate (IBXMA), isobornyl acrylate (IBXA), In addition to dicyclopentanyl acrylate (DCPA), 1-adamantyl methacrylate (ADMA), and 1-adamantyl acrylate (ADA) homopolymers, a copolymer of CHMA and isobutyl methacrylate (IBMA), CHMA and IBXMA Copolymer, Copolymer of CHMA and acryloylmorpholine (ACMO), Copolymer of CHMA and diethylacrylamide (DEAA), Copolymer of ADA and methyl methacrylate (MMA), DCPMA and IB Copolymers of MA, copolymers of DCPMA and MMA, and the like.

When the (meth) acrylic oligomer is contained in the resin layer forming composition disclosed herein, the content thereof is not particularly limited, and is approximately about 100 parts by weight of the monomer component contained in the resin layer forming composition. It is appropriate that the amount is 1 part by weight or more. From the viewpoint of better exhibiting the effect of the (meth) acrylic oligomer, the content of the (meth) acrylic oligomer is 3 parts by weight or more (for example, 5 parts by weight or more, typically 8 parts by weight or more). It is preferable to do. In addition, the content of the (meth) acrylic oligomer from the viewpoint of the curability of the resin layer forming composition and the compatibility with the partial polymer or the complete polymer of the acrylic polymer (and thus the transparency of the resin layer). Is suitably 70 parts by weight or less (for example 40 parts by weight or less, typically 20 parts by weight or less) with respect to 100 parts by weight of the monomer component contained in the resin layer forming composition. The technique disclosed here can also be implemented in an embodiment that does not use a (meth) acrylic oligomer.

(Silane coupling agent)
Further, the resin layer forming composition disclosed herein may contain a silane coupling agent. Examples of silane coupling agents that can be preferably used include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2- (3,4-epoxy. (Cyclohexyl) ethyltrimethoxysilane and other epoxy group-containing silane coupling agents; 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- ( Amino group-containing silane coupling agents such as 1,3-dimethylbutylidene) propylamine, N-phenyl-γ-aminopropyltrimethoxysilane; 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. (Meth) acrylic group Isocyanate group-containing silane coupling agents such as 3-isocyanate propyl triethoxysilane; Yes silane coupling agent, and the like. These can be used alone or in combination of two or more. The amount of the silane coupling agent is preferably 1 part by weight or less (for example, 0.01 to 1 part by weight), more preferably 0.02 to 100 parts by weight with respect to 100 parts by weight of the monomer component constituting the acrylic polymer. 0.6 parts by weight.

(Crosslinking agent)
The composition for resin layer formation disclosed here can contain a crosslinking agent. Examples of the crosslinking agent include an epoxy crosslinking agent, an isocyanate crosslinking agent, a silicone crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, a silane crosslinking agent, an alkyl etherified melamine crosslinking agent, and a metal chelate crosslinking agent. Etc. These can be used alone or in combination of two or more. The addition amount of a crosslinking agent is appropriately set based on technical common sense. Or the composition for resin layer formation may not contain the above crosslinking agents.

(Other additives)
In addition, the resin layer forming composition disclosed herein may contain various additives known in the field of pressure-sensitive adhesives, for example. For example, powders such as colorants, pigments, dyes, surfactants, plasticizers, tackifying resins, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, UV absorbers, A polymerization inhibitor, an inorganic or organic filler, metal powder, particles, foils, etc. can be appropriately added depending on the application.

(Formation method, etc.)
The resin layer disclosed herein can be formed, for example, as a resin layer by applying any of the resin layer forming compositions disclosed herein to a support and drying or curing. As a coating method of the resin layer forming composition, various conventionally known methods can be used. Specifically, for example, by roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples thereof include an extrusion coating method.

The resin layer forming composition can be dried under heating. The drying temperature is preferably 40 ° C to 200 ° C, more preferably 50 ° C to 180 ° C, and further preferably 70 ° C to 170 ° C. By setting the heating temperature within the above range, a resin layer having excellent physical properties can be obtained. As the drying time, an appropriate time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and even more preferably 10 seconds to 5 minutes.

In forming the resin layer, in order to obtain desired physical properties, a crosslinking treatment, a thermosetting treatment, or the like can be further performed. For example, a thermosetting treatment can be performed at about 80 to 200 ° C. (eg, 100 to 180 ° C., typically 120 to 160 ° C.) for 5 minutes or more. The heat curing treatment time is preferably 10 minutes or longer, more preferably 20 minutes or longer (for example, 30 minutes or longer, typically 40 minutes to 120 minutes). The resin layer is preferably subjected to press treatment before or during the thermosetting treatment.

The resin layer disclosed herein can be obtained from the resin layer forming composition. The thickness of the resin layer is not particularly limited, and can be, for example, about 1 to 400 μm. Usually, the thickness of the resin layer is preferably 1 to 200 μm, more preferably 2 to 150 μm, further preferably 2 to 100 μm, and particularly preferably 5 to 75 μm.

In a mode in which the conductive portion is laminated on the resin layer in advance, the resin layer before the conductive portion is placed is spirally overlapped with a release liner (support) whose front surface and back surface are both release surfaces (peelable surfaces). It may be in a form wound in a shape. Alternatively, the first surface and the second surface may be respectively protected by two independent release liners (supports). As the release liner, those described below can be preferably used.

<Release liner>
As the release liner for protecting the first resin layer, the second resin layer, and the upper and lower surfaces of the wiring structure, a conventional release paper or the like can be used, and is not particularly limited. For example, a release liner having a release treatment layer on the surface of a substrate such as a plastic film or paper, or a release made of a low adhesive material such as a fluorine polymer (polytetrafluoroethylene, etc.) or a polyolefin resin (polyethylene, polypropylene, etc.) A liner or the like can be used. The release treatment layer may be formed by surface-treating the base material with a release treatment agent. Examples of the release treatment agent include a silicone release treatment agent, a long-chain alkyl release treatment agent, a fluorine release treatment agent, and molybdenum (IV) sulfide.

<Solar cell>
The type of the solar battery cell to be used is not particularly limited, and for example, a single crystal type or a polycrystalline type Si cell is suitable. The crystalline Si cell may be a p-type cell (a cell in which n-type is added to a p-type substrate) or an n-type cell (a cell in which p-type is added to an n-type substrate). Further, the solar battery cell may be an amorphous Si cell, a compound solar battery, an organic solar battery cell or the like. Further, the solar cell may be either a single-sided light receiving type or a double-sided light receiving type. The shape of the solar battery cell is not particularly limited, and it may be a wafer having a substantially rectangular plane, or may be a belt shape. As the electrode formed in the solar battery cell, the configuration of the second embodiment is preferably employed, but is not limited thereto, and a known or conventional electrode can be appropriately employed depending on the purpose or the like. The thickness of the solar battery cell is preferably about 0.5 mm or less, more preferably about 0.3 mm or less (for example, about 180 to 200 μm), and further preferably about 160 μm or less from the viewpoint of lightness and the like.

<Sealing resin>
The sealing resin disclosed herein may have insulating properties and translucency. For example, it may be a resin layer that can exhibit fluidity by heat or pressure. In this specification, “having insulation” means a specific resistance at 25 ° C. of 1 × 10 ⁶ Ω · cm or more (preferably 1 × 10 ⁸ Ω · cm or more, typically 1 × 10 ¹⁰ Ω). -Cm or more). In this specification, the electric resistance (for example, specific resistance) is a value at 25 ° C. unless otherwise specified. Further, in the present specification, “having translucency” means that the total light transmittance defined by JIS K 7375: 2008 is 50% or more (preferably 80% or more, typically 95% or more). That means.

The sealing resin may preferably be a thermosetting resin. The sealing resin made of a thermosetting resin can be well sealed in the solar battery module by, for example, laminating and heating the solar battery cell. As the resin, an ethylene-vinyl acetate copolymer (EVA) is preferably used from the viewpoints of translucency, workability, weather resistance, and the like. The above resins include ethylene-vinyl ester copolymers represented by EVA, ethylene-unsaturated carboxylic acid copolymers such as ethylene- (meth) acrylic acid copolymers, ethylene- (meth) acrylic acid esters, etc. An ethylene-unsaturated carboxylic acid ester copolymer, an unsaturated carboxylic acid ester-based polymer such as polymethyl methacrylate, and the like may be used. Alternatively, fluoropolymers such as vinylidene fluoride resin and polyethylene tetrafluoroethylene; manufactured using low density polyethylene (LDPE), linear low density polyethylene (LLDPE, typically Ziegler catalyst, vanadium catalyst, metallocene catalyst, etc. Can be produced using polyethylene (PE) such as LLDPE), polypropylene (PP. For example, PP that can be produced using Ziegler catalyst, Phillips catalyst, metallocene catalyst, etc.), Ziegler catalyst, vanadium catalyst, metallocene catalyst, etc. Polyolefins such as ethylene / α-olefin copolymers and their modified products (modified polyolefins); Polybutadienes; Polyvinyl acetals such as polyvinyl formal, polyvinyl butyral (PVB resin), and modified PVB; polyethylene Terephthalate (PET); polyimide; amorphous polycarbonate; siloxane sol - gel; polyurethane; polystyrene; polyether sulfone; polyarylate, epoxy resins, may be like; silicone resin; ionomers. These resins may be used alone or in combination of two or more. The resin may contain various additives known in the art such as an ultraviolet absorber and a light stabilizer.

In addition, an adhesion improver may be added to the sealing resin in order to improve the adhesion with the wiring structure. For example, after an adhesion improver is applied to the surface of the sheet-shaped sealing resin before heat curing, the wiring structure is disposed on the surface, and the sealing resin and the wiring structure are heat-treated. Adhesion with is improved. When an EVA sheet is used as the sealing resin, a silane coupling agent is preferably used as the adhesion improver. Various surface treatments such as corona treatment and atmospheric pressure plasma treatment can be applied to the surface of the sheet-shaped sealing resin alone or in combination for the purpose of improving adhesion and the like.

The thickness of the sheet-shaped sealing resin used for the construction of the solar cell module is about 100 to 2000 μm (for example, 200 to 1000 μm, typically 400 to 800 μm) from the viewpoint of the sealing performance of the solar battery cell. It is preferable.

<Surface covering member>
As the surface covering member, various materials having translucency can be used. Surface covering member is glass plate, fluororesin sheet such as tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride resin, chlorotrifluoroethylene resin, acrylic resin, polyethylene terephthalate It may be a resin sheet composed of a material such as polyester such as (PET) or polyethylene naphthalate (PEN). For example, a flat plate member or a sheet member having a total light transmittance of 70% or more (for example, 90% or more, typically 95% or more) can be preferably used. The total light transmittance may be measured according to JIS K 7375: 2008. The thickness of the surface covering member is preferably about 0.5 to 10 mm (for example, 1 to 8 mm, typically 2 to 5 mm) from the viewpoint of protection and light weight.

<Backside coating member>
As the back surface covering member, a flat plate member or a sheet member made of various materials exemplified as the material of the surface covering member is preferably used. Especially, it is more preferable to use polyester, such as PET and PEN, as a back surface covering member forming material. Or as a back surface covering member, you may use the metal sheet (for example, aluminum plate) which has corrosion resistance, resin sheets, such as an epoxy resin, and composite sheets, such as silica vapor deposition resin. The thickness of the back surface covering member is preferably about 0.1 to 10 mm (for example, 0.2 to 5 mm) from the viewpoints of handleability and lightness. In addition, the back surface covering member may not have translucency.

Hereinafter, examples relating to the present invention will be described, but the present invention is not intended to be limited to those shown in the specific examples. In the following description, “parts” and “%” are based on weight unless otherwise specified.

≪Experiment 1≫
<Materials used>
(First resin layer and second resin layer)
40.5 parts of 2-ethylhexyl acrylate, 40.5 parts of isostearyl acrylate, 18 parts of N-vinyl-2-pyrrolidone, 1 part of 4-hydroxybutyl acrylate, and 2,2-dimethoxy-1, as a photopolymerization initiator 0.05 part of 2-diphenylethane-1-one (trade name “Irgacure 651”, manufactured by BASF) and 0.05 part of 1-hydroxycyclohexyl-phenyl-ketone (trade name “Irgacure 184”, manufactured by BASF) Were mixed and irradiated with ultraviolet rays in a nitrogen atmosphere to prepare a partially polymerized product (monomer syrup). To the obtained monomer syrup, 0.3 part of a silane coupling agent (trade name “KBM403”, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.02 part of trimethylolpropane triacrylate (TMPTA) are added and mixed uniformly. A layer forming composition was prepared.
The composition for forming a resin layer prepared above is applied to the release treatment surface of a 38 μm thick polyester film (trade name “Diafoil MRF”, manufactured by Mitsubishi Plastics, Inc.) whose one surface is release-treated with a silicone release treatment agent. The coated layer was formed by coating so that the final thickness was 50 μm. Next, a 38 μm thick polyester film (trade name “Diafoil MRE”, manufactured by Mitsubishi Plastics Co., Ltd.) having one side peeled with silicone is applied to the surface of the coating layer. I put it on the side. Thereby, the coating layer was shielded from oxygen. By irradiating the sheet having the coating layer thus obtained with ultraviolet rays having an illuminance of 5 mW / cm ² for 360 seconds using a chemical light lamp (manufactured by Toshiba Corporation), the coating layer is cured and a resin layer (adhesive) Agent layer) was formed to obtain resin sheets (adhesive sheets) as the first resin layer and the second resin layer. In this resin sheet, the polyester film coated on both surfaces of the resin sheet functions as a release liner.
The illuminance value is a value measured by an industrial UV checker (trade name “UVR-T1”, light receiving unit type UD-T36, manufactured by Topcon Corporation) having a peak sensitivity wavelength of about 350 nm.

(Conductive part)
A copper wire (width 0.8 mm, thickness 0.25 mm) was prepared. A copper wire having a width tolerance of ± 10%, a thickness tolerance of ± 4%, a plating thickness of 1 μm (tolerance of ± 15%), and a tensile strength of 200 N / mm ² or more was used. Ag was used as the plating type.

(Sealing resin)
EVA sheet (trade name “EVASKY”, manufactured by Bridgestone, thickness 450 μm)
(Solar cell)
Si solar cell (polycrystalline Si cell, manufactured by GINTECH)
(Surface covering member)
Glass plate (white plate heat-treated glass, manufactured by Asahi Glass Co., Ltd., thickness 3.2 mm)
(Back cover member)
Back sheet (trade name “KOBATEC PV KB-Z1-3”, manufactured by Kobayashi Corporation, thickness 200 μm)

<Example>
Using the above materials, a test solar cell module having the same configuration as that of the first embodiment was constructed. In this solar cell module for test, two solar cells were used. Resin sheets as the first resin layer and the second resin layer were cut into appropriate sizes in accordance with the shape of the solar battery cells and arranged in the first region and the second region, respectively. Eight copper wires were used as the conductive part, and the copper wires were arranged at 2 cm intervals so that the longitudinal direction of the copper wires was parallel to the arrangement direction of the solar cells. The sealing resin was also cut into an appropriate size according to the shape of the module. The solar cell module for testing was placed on the above materials, then laminated using a commercially available laminator (manufactured by NPC) at 150 ° C. and 100 kPa for 5 minutes, cured for 15 minutes, and further commercially available. This was constructed by performing a drying treatment at 150 ° C. for 15 minutes using a blast constant temperature thermostat (manufactured by Yamato Kagaku Co., Ltd.).

<Comparative example>
A Si-based solar cell in which bus bar electrodes (trade name “SSA-SPS”, 1.5 mm × 0.2 mm solder-coated copper wire, manufactured by Hitachi Cable Ltd.) are fixed by solder bonding without using a wiring structure ( A solar cell module according to a comparative example was constructed in the same manner as in the above example except that a polycrystalline cell manufactured by GINTECH was used.

[Power generation efficiency]
About the obtained solar cell module, based on JIS C 8913: 2005, the light conversion efficiency (%) was measured on condition of the following using a solar simulator (device name "XES-450S1," manufactured by Mitsunaga Electric Mfg. Co., Ltd.). .
(Measurement condition)
Voltage sweep method Start voltage: -0.01V
Stop voltage: 1.6V
Step: 0.02V
Current limit: 10000A
Retention time: 26.68ms
Light amount: Reference PV CELL (trade name “AK-200”, manufactured by Konica Minolta, Inc.) was used to adjust the short-circuit current to about 129 mA (± 3%).

As a result of the evaluation, the conversion efficiency of the example was 17.30%, while the conversion efficiency of the comparative example was 16.53%. By applying the technology disclosed herein, an efficiency improvement of about 4.6% was realized compared to the conventional product using soldered bus bar electrodes. In addition, preparing three types of resin sheets (adhesive sheets) different from the examples such as changing the monomer type, using these as the first resin layer and the second resin layer, respectively, constructing solar cell modules for testing, When the power generation efficiency was evaluated, all of them achieved a conversion efficiency of 17.20% or more.
Moreover, when the presence or absence of the defect in the photovoltaic cell of the solar cell module for a test was confirmed by the EL (Electro-Luminescence) inspection image, as shown in FIG. 9, defects such as cracks and disconnection were not recognized.
From the above, it can be seen that by using the wiring structure disclosed herein, wiring workability at the time of construction of the solar cell module is improved, and the obtained solar cell module is excellent in reliability of wiring connection. Moreover, the power generation efficiency of a solar cell module can be improved by using the wiring structure disclosed here.

≪Experiment 2≫
<Materials used>
A plurality of plated copper wires (width 0.8 mm, thickness 0.25 mm, rectangular cross section) shown in Table 1 were prepared as conductive portions. The plated copper wire used had a width tolerance of ± 10%, a thickness tolerance of ± 4%, a plating thickness of 1.5 μm or more, and a tensile strength of 200 N / mm ² or more. As the plating type, silver having the purity shown in Table 1 was used. The roughness of the conductive part surface and the diffuse reflectance are adjusted by the etching process of the copper wire, the purity of the silver plating, and the plating thickness (film thickness).
As the 1st resin layer and the 2nd resin layer, the thing similar to the said experiment 1 was prepared except the thickness having been 46 micrometers.
As other materials, the same materials as in Experiment 1 were prepared.

<Samples 2-1 to 2-9>
Using the above materials, a test solar cell module having the same configuration as that of the first embodiment was constructed. In this solar cell module for test, two solar cells were used. The resin sheets as the first resin layer and the second resin layer were each cut into an appropriate size according to the shape of the solar battery cell, and placed in two solar battery cells. As the conductive part, eight plated copper wires shown in Table 1 were used, and the copper wires were arranged at 2 cm intervals so that the longitudinal direction of the copper wires was parallel to the arrangement direction of the solar cells. The sealing resin was also cut into an appropriate size according to the shape of the module. The solar cell module for testing was placed on the above materials, then laminated using a commercially available laminator (manufactured by NPC) at 150 ° C. and 100 kPa for 5 minutes, cured for 15 minutes, and further commercially available. This was constructed by performing a drying treatment at 150 ° C. for 15 minutes using a blast constant temperature thermostat (manufactured by Yamato Kagaku Co., Ltd.).

<Reference sample>
Without using the conductive part and the first and second resin layers, three bus bar electrodes (trade name “SSA-SPS”, 1.5 mm × 0.2 mm solder-coated copper wire, manufactured by Hitachi Cable Ltd.) are soldered together A solar cell module was constructed in the same manner as the above sample except that the Si-based solar cells (polycrystalline cell manufactured by GINTECH) were used.

With respect to the solar cell module obtained above, a short circuit current Jsc (mA / cm ² ) was measured using a solar simulator (device name “XES-450S1”, manufactured by Mitsunaga Electric Mfg. Co., Ltd.). The results are shown in Table 1 and FIG. The table also shows the diffuse reflectance (%), silver plating purity (%), and Ra (μm) on the surface of the conductive part. In the table, “-” represents unmeasured.

As shown in Table 1 and FIG. 10, the diffuse reflectance on the surface of the conductive part and the short-circuit current Jsc showed a positive proportional relationship. In particular, Samples 2-1 to 2-6 in which the diffuse reflectance on the surface of the conductive part was 60% or more showed a relatively high short-circuit current Jsc. From this result, it can be seen that the power generation efficiency is improved according to the solar cell module using the conductive portion having a diffuse reflectance of 60% or more on the solar cell module light incident surface side.

≪Experiment 3≫
A plurality of plated copper wires (width 0.8 mm, thickness 0.25 mm, rectangular cross section) having different plating thicknesses were prepared as the conductive portions. As the plated copper wire, one having a width tolerance of ± 10%, a thickness tolerance of ± 4%, a tensile strength of 200 N / mm ² or more, and a plating type of silver having a purity of 99.9 wt% or more was used. About the said electroconductive part, the diffuse reflectance (%) of the surface was measured. FIG. 11 shows the relationship between the plating thickness (μm) and the diffuse reflectance (%).

As shown in FIG. 11, the diffuse reflectance improved as the plating thickness of the conductive part increased. In particular, it was shown that when the plating thickness is 1.5 μm or more, a diffuse reflectance of 90% or more is realized. In Experiment 2, since the diffuse reflectance of the surface of the conductive part and the short circuit current Jsc show a positive proportional relationship, it can be seen that the power generation efficiency can be improved by increasing the plating thickness of the conductive part.

≪Experiment 4≫
<Sample 4-1>
Test solar cell modules were constructed using the materials used in Experiment 1 above. Specifically, a conductive portion is disposed on the upper surface of one solar cell, a first resin layer is disposed thereon, a conductive portion is disposed on the lower surface of the solar cell, and a second resin is disposed below the conductive portion. Layers were placed. Eight copper wires were used as the conductive portions, and were arranged at 2 cm intervals so as to be parallel to each other. Two copper terminal bars were installed on both sides of the solar battery cell as take-out electrodes, and fixed to conductive parts (copper wires) arranged vertically. Furthermore, what placed sealing resin on the upper and lower sides was sandwiched between the surface covering member and the back surface covering member. Next, using a commercially available laminator (manufactured by NPC), laminating is carried out under conditions of 150 ° C. and 100 kPa for 5 minutes, curing for 15 minutes, and further, a commercially available air blow thermostat (manufactured by Yamato Kagaku) A solar cell module for test was constructed by performing a drying treatment at 150 ° C. for 15 minutes.

<Sample 4-2>
Without using the conductive part and the first and second resin layers, three bus bar electrodes (trade name “SSA-SPS”, 1.5 mm × 0.2 mm solder-coated copper wire, manufactured by Hitachi Cable Ltd.) are soldered together A test solar cell module was constructed in the same manner as Sample 4-1, except that the Si-based solar cell (polycrystalline cell, manufactured by GINTECH) was used.

[Dump heat (DH) test]
About the solar cell module for a test obtained above, DH test was implemented on 85 degreeC85% RH conditions. The module was taken out before the test was started (initially) and at predetermined intervals (approximately every 500 hours) from the start of the test, the light conversion efficiency was measured, and the maintenance ratio (%) of the light conversion efficiency with respect to the initial light conversion efficiency was evaluated. . The results are shown in FIG. FIG. 12 also shows an EL inspection image of the solar battery cell after completion of the DH test. The light conversion efficiency was measured by the same method as in Experiment 1 above.

As shown in FIG. 12, in the DH test, samples 4-1 and 4-2 showed the same tendency until 3000 hours, but after 3,000 hours, sample 4-1 had a high conversion efficiency. While the retention rate was exhibited, the conversion efficiency of the conventional sample 4-2 tended to decrease significantly. From this result, it is understood that a solar cell module having excellent durability can be realized by applying the technology disclosed herein.

≪Experiment 5≫
(Cell surface electrode effect verification test 1)
<Materials used>
A copper wire (width 0.8 mm, thickness 0.25 mm) was prepared as the conductive wire. A copper wire having a width tolerance of ± 10%, a thickness tolerance of ± 4%, a plating thickness of 1 μm (tolerance of ± 15%), and a tensile strength of 350 N / mm ² or more was used. Ag was used as the plating type.
As a surface covering member, a polycarbonate plate (trade name “PC1600”, manufactured by Takiron Co., Ltd., thickness 2 mm) was prepared.
As the first resin layer, the sealing resin, the solar battery cell, and the back surface covering member, the same materials as those in Experiment 1 were prepared.

<Sample 5-1>
A test solar cell module was constructed using the above materials. Specifically, the solar battery cell was cut into a 5 cm square. As shown in FIG. 13, on the surface of the solar cell SC, one bus bar electrode BE is arranged at the center, and a plurality of finger electrodes FE orthogonal to the bus bar electrode BE are arranged. The width of the finger electrode FE is approximately in the range of 40 to 80 μm. Two conductive lines CW were arranged on the upper surface of the solar cell SC so as not to contact the finger electrode FE but to contact the bus bar electrode BE only at one point. Specifically, one conductive line CW is arranged on one end side of the bus bar electrode BE, and the other conductive line CW is arranged on the other end side of the bus bar electrode BE. The two conductive lines CW are each parallel to the longitudinal direction of the finger electrode FE, and thus the two conductive lines CW are parallel to each other. The distance between them was 3 cm. The upper surface (front surface) of the solar battery cell SC on which the conductive line CW is arranged is schematically shown in FIG. The 1st resin layer was arrange | positioned on the photovoltaic cell SC which has arrange | positioned the said conductive wire CW. Furthermore, what placed sealing resin on the upper and lower sides was sandwiched between the surface covering member (polycarbonate plate) and the back surface covering member. Next, using a commercially available laminator (manufactured by NPC), laminating is carried out under conditions of 150 ° C. and 100 kPa for 5 minutes, curing for 15 minutes, and further, a commercially available air blow thermostat (manufactured by Yamato Kagaku) A solar cell module for test was constructed by performing a drying treatment at 150 ° C. for 15 minutes. As schematically shown in FIG. 14, the test solar cell module TM has a rectangular shape (size of 7 cm × 15 cm), and a solar cell SC is arranged at the center thereof. The two conductive lines CW extend to one short side (7 cm side) and the other short side constituting the outer edge of the test solar cell module TM, and are exposed to the outside of the module TM.

<Sample 5-2>
As shown in FIG. 15, each of the two conductive lines CW is disposed so as to run on the finger electrode FE, and is in line contact with the bus bar electrode BE at one point while being in contact with the finger electrode FE. Otherwise, a test solar cell module was constructed in the same manner as in Sample 5-1.

[Evaluation of conduction reliability]
Using the test solar cell module (7 cm × 15 cm rectangular module) prepared above, the resistance value (initial resistance value) between two points from two conductive wires was measured. Next, the resistance value was measured in a state where the test solar cell module was deformed stepwise so that the long side of the test solar cell module was bent convexly toward the upper surface side of the solar cell. FIG. 16 shows the relationship between the resistance value change (times) and the strain deformation amount (mm) with respect to the initial resistance value. Note that the strain deformation amount is the strain height (arrow height) of the test solar cell module TM bent into a convex shape in an arc shape as schematically shown in FIG.

As shown in FIG. 16, in Sample 5-2 in which conductive wires and finger electrodes were linearly overlapped, the resistance did not increase even when the solar cell module was deformed. In contrast, in sample 5-1, in which the conductive wire was in contact only with the bus bar electrode, the resistance increased greatly as the amount of deformation of the solar cell module increased. From this result, it is understood that the conduction reliability can be improved by providing a linear portion extending along the conductive line on the surface electrode of the solar battery cell and overlapping the linear portion with the conductive line.
In Sample 5-2, since the resistance did not increase even though the width of the finger electrode was smaller than the width of the conductive line, the width of the linear portion provided on the surface of the solar battery cell was as follows. It can be seen that good conduction reliability can be obtained even with a narrower width.

≪Experiment 6≫
(Cell surface electrode effect verification test 2)
<Materials used>
A copper wire (width 0.8 mm, thickness 0.25 mm) was prepared as the conductive wire. A copper wire having a width tolerance of ± 10%, a thickness tolerance of ± 4%, a plating thickness of 1 μm (tolerance of ± 15%), and a tensile strength of 350 N / mm ² or more was used. Ag was used as the plating type.
As a surface covering member, a polycarbonate plate (trade name “PC1600”, manufactured by Takiron Co., Ltd., thickness 2 mm) was prepared.
As the first resin layer, the sealing resin, and the back surface covering member, the same materials as those in Experiment 5 were prepared.
As the solar cell, the basically same cell as in Experiment 1 was used. The solar cell used in this experiment has a surface electrode formed as described later.

<Sample 6-1>
Using the above materials, a test solar cell module was constructed by the following method. Specifically, as shown schematically in FIG. 18 (a), a solar cell SC of approximately 6 inches square having three finger electrodes FE printed in parallel on the surface at intervals was prepared. On this solar cell SC, as shown in FIG. 18B, two conductive lines CW were arranged so as to be orthogonal to the three finger electrodes FE of the solar cell SC. These two conductive lines CW are parallel to each other with an interval of 10 cm, and are arranged so as to contact each of the three finger electrodes FE only at one point. The 1st resin layer was arrange | positioned on the photovoltaic cell SC which has arrange | positioned the said conductive wire CW. Furthermore, what placed sealing resin on the upper and lower sides was sandwiched between a surface covering member (polycarbonate plate) of about 20 cm square and a back surface covering member of about 20 cm square. Next, using a commercially available laminator (manufactured by NPC), laminating is carried out under conditions of 150 ° C. and 100 kPa for 5 minutes, curing for 15 minutes, and further, a commercially available air blow thermostat (manufactured by Yamato Kagaku) A solar cell module for test was constructed by performing a drying treatment at 150 ° C. for 15 minutes.

<Sample 6-2>
About 6 inch square solar cells SC schematically shown in FIG. 19A were prepared. On the surface of the solar cell SC, as shown in the figure, there are three finger electrodes FE parallel to each other at intervals, and an orthogonal electrode PE (Perpendicular Electrode surface electrode first linear) perpendicular to the finger electrodes FE. Corresponding to the portion, also referred to as a conductive wire contact portion). The distance between the two orthogonal electrodes PE shown on the surface of the solar cell SC in FIG. 19A is 10 cm. On this solar cell SC, as shown in FIG. 19B, two conductive lines CW were disposed on the lines of the two orthogonal electrodes PE, respectively. The conductive line CW is in continuous contact with the orthogonal electrode PE and in contact with each of the three finger electrodes FE. A test resin module was constructed in the same manner as Sample 6-1 except that the first resin layer was disposed thereon.

[Evaluation of conduction reliability]
For the test solar cell module produced, a digital multimeter cable (model “VOAC7522”, manufactured by Iwasaki Keiki Co., Ltd.) is attached to the end of the two conductive wires on the diagonal line, and the resistance value (initial) Resistance value) was measured. Next, the test solar cell module is subjected to a heat treatment at 80 ° C. for 5 minutes with a commercially available air constant temperature thermostat (manufactured by Yamato Kagaku Co., Ltd.) so that the back surface side of the solar cell faces upward (so that it becomes the upper surface ), The test solar cell module was fixed on two sides (two sides facing each other) on the side from which the conductive wire was drawn. Then, a 4 kg weight was placed on the upper surface, and a load was applied for 5 minutes. The test solar cell module after applying the load is bent using a stretching machine so that the light-receiving surface side is convex, and the amount of distortion deformation (synonymous with the amount of distortion deformation shown in FIG. 17. The strain was applied until 2 cm was obtained. After that, heat treatment is further performed at 80 ° C. for 5 minutes in a ventilation constant temperature thermostat (manufactured by Yamato Kagaku Co., Ltd.), and this time, with the surface (light receiving surface) side of the solar cell facing upward (to be the upper surface) The test solar cell module was fixed at the two sides. Then, a 4 kg weight was placed on the upper surface, and a load was applied for 5 minutes. The test solar cell module after applying the load is bent using a stretching machine so that the back side is convex, and the amount of strain deformation (synonymous with the amount of strain deformation shown in FIG. 17; also referred to as strain height). .) Was strained to 2 cm. In that state (that is, in a state where the strain deformation amount is 2 cm), the resistance value (resistance value at deformation) is measured in the same manner as the initial resistance value, and the formula: resistance increase rate (%) = (resistance value at deformation−initial value) Resistance value) / initial resistance value; the rate of increase in resistance (%) was determined and used as an index of conduction reliability. The results are shown in Table 2.

As shown in Table 2, in Sample 6-2 in which conductive wires and electrodes (orthogonal electrodes) are linearly overlapped, the resistance increase rate is suppressed to about 40% even if the test solar cell module is deformed. I was able to. On the other hand, in the sample 6-1 in which the conductive wire was in contact only with the finger electrode, the resistance increase rate increased and exceeded 170%. From this result, it is understood that the conduction reliability can be improved by providing a linear portion extending along the conductive line on the surface electrode of the solar battery cell and overlapping the linear portion with the conductive line.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

DESCRIPTION OF SYMBOLS 1 Wiring structure 2 Wiring structure with release liner 10 1st area | region 12 2nd area | region 30 Conductive part 40,240 Conductive line 50 1st resin layer 60 2nd resin layer 70 1st release liner 72 2nd release liner 74 3rd Release liner 76

Fourth release liner

100, 200

Solar cell module

110a, 110b, 110c, 110d, 210 Solar cell 120 Wired solar cell group 150 Sealing resin 160 Surface covering member 170 Back surface covering member 212 Electrode (surface electrode)
214 First linear portion 216 Second linear portion

Claims

A wiring structure spanning from the upper surface of one of the two solar cells arranged in the solar cell module to the lower surface of the other solar cell,
A first region corresponding to the one solar cell, and a second region corresponding to the other solar cell,
A conductive portion continuous from the first region to the second region;
A first resin layer disposed above the conductive portion in the first region;
A second resin layer disposed below the conductive portion in the second region;
With
The conductive structure is a wiring structure that is partially disposed in the first region.
The conductive portion is composed of a plurality of conductive lines extending from the first region to the second region,
The wiring structure according to claim 1, wherein the plurality of conductive lines are arranged at intervals.
The wiring structure according to claim 2, wherein the conductive wire is a plated copper wire.
The wiring structure according to claim 3, wherein the plating is silver plating.
The wiring structure according to claim 4, wherein the silver plating has a purity of 99.7% by weight or more.
The wiring structure according to any one of claims 3 to 5, wherein the conductive wire exhibits a diffuse reflectance of 60% or more.
The wiring structure according to any one of claims 1 to 6, wherein each of the first resin layer and the second resin layer is an adhesive layer.
The wiring structure according to any one of claims 1 to 7, wherein each of the first resin layer and the second resin layer is a crosslinked adhesive layer.
The storage elastic modulus (frequency 1 Hz, strain 0.1%, 150 ° C.) of the first resin layer and the second resin layer are both 5000 Pa or more, and tan δ at 80 ° C. to 150 ° C. is less than 0.4. The wiring structure according to any one of claims 1 to 8, wherein
A wiring structure according to any one of claims 1 to 9,
A first release liner disposed on an upper surface of the first resin layer in the first region;
A second release liner disposed on the lower surface of the conductive portion in the first region;
A third release liner disposed on the upper surface of the conductive portion in the second region;
A fourth release liner disposed on the lower surface of the second resin layer in the second region;
A wiring structure with a release liner.
A solar cell module comprising the wiring structure according to any one of claims 1 to 9.
A plurality of solar cells arranged at intervals, and
Conductivity that is connected from the upper surface of one solar cell of two adjacent solar cells to the lower surface of the other solar cell among the plurality of solar cells and electrically connects the two adjacent solar cells. And
A first resin layer disposed above one of the two adjacent solar cells;
A second resin layer disposed below the other solar cell of the two adjacent solar cells;
With
The conductive portion is disposed between the one solar cell and the first resin layer, and between the other solar cell and the second resin layer, and the one solar cell. A solar cell module partially disposed on the upper surface of the solar cell module.
The conductive portion is composed of a plurality of conductive lines extending from the upper surface of one solar cell of the two adjacent solar cells to the lower surface of the other solar cell,
The solar cell module according to claim 12, wherein the plurality of conductive lines are arranged at intervals.
The solar cell module according to claim 13, wherein the conductive wire is a plated copper wire.
The solar cell module according to claim 14, wherein the plating is silver plating.
The solar cell module according to claim 15, wherein the silver plating has a purity of 99.7% by weight or more.
The solar cell module according to any one of claims 13 to 16, wherein the conductive wire exhibits a diffuse reflectance of 60% or more.
The first resin layer is not disposed above the other solar cell, and the second resin layer is not disposed below the one solar cell. A solar cell module according to claim 1.
The solar cell module according to any one of claims 12 to 18, wherein each of the first resin layer and the second resin layer is an adhesive layer.
The solar cell module according to any one of claims 12 to 19, wherein each of the first resin layer and the second resin layer is a crosslinked adhesive layer.
The storage elastic modulus (frequency 1 Hz, strain 0.1%, 150 ° C.) of the first resin layer and the second resin layer are both 5000 Pa or more, and tan δ at 80 ° C. to 150 ° C. is less than 0.4. The solar cell module according to any one of claims 12 to 20, wherein
An electrode is provided on each surface of the plurality of solar cells,
The electrode includes a plurality of first linear portions extending linearly along the plurality of conductive lines, and a plurality of second linear portions extending linearly so as to intersect the first linear portions. The solar cell module according to any one of claims 13 to 17, comprising:
The solar cell module according to claim 22, wherein a width of the first linear portion is smaller than a width of the conductive line.
The ratio (W1 / W2) between the width W1 of the first linear portion and the width W2 of the second linear portion is in the range of 0.1 to 10, according to claim 22 or 23. Solar cell module.
The electrode provided on the surface of the solar cell is in contact with the conductive wire at the first linear portion, and no adhesive means is used for the contact. A solar cell module according to claim 1.
A solar cell module comprising a plurality of solar cells arranged at intervals,
A plurality of the plurality of adjacent solar cells that are connected from the upper surface of one of the two adjacent solar cells to the lower surface of the other solar cell and electrically connect the two adjacent solar cells. With conductive wires
In the solar cell module, an electrode is provided on each surface of the plurality of solar cells,
The electrode includes a plurality of first linear portions extending linearly along the plurality of conductive lines, and a plurality of second linear portions extending linearly so as to intersect the first linear portions. And having
The solar cell module, wherein a width of the first linear portion is smaller than a width of the conductive line.
A solar battery cell with electrodes provided on the surface,
The electrode has a plurality of first linear portions extending linearly, and a plurality of second linear portions extending linearly so as to intersect the first linear portions,
The width of the first linear portion is a solar cell that is smaller than the width of a conductive line that electrically connects the solar cell and another solar cell.