WO2017119036A1 - Solar cell module - Google Patents

Abstract

A solar cell module (1) is provided with: two solar cell elements (11) adjacent to each other in the direction parallel to a light receiving surface; tab wiring (20), which is disposed on the front surface of one of the two solar cell elements (11), and the rear surface of the other solar cell element, and which electrically connects the two solar cell elements (11) to each other; a plurality of finger electrodes (111); a bus bar electrode (112) formed to extend in the direction intersecting the finger electrodes (111); and a bonding member (40) that bonds the bus bar electrode (112) and the tab wiring (20) to each other such that the bus bar electrode (112) and the tab wiring (20) overlap each other in plan view. Intersection parts (Px) where the bus bar electrode (112) intersects the finger electrodes (111) are thicker than non-intersection parts (Py), each of which is sandwiched between the intersection parts (Px) of the bus bar electrode (112), said intersection parts being adjacent to each other.

Description

Solar cell module

The present invention relates to a solar cell module.

Conventionally, solar cell modules are being developed as photoelectric conversion devices that convert light energy into electrical energy. The solar cell module is expected as a new energy source because it can convert inexhaustible sunlight directly into electricity, and it has a smaller environmental load and is cleaner than power generation using fossil fuels.

The solar cell module has, for example, a structure in which a plurality of solar cell elements are sealed with a filling member between a surface protection member and a back surface protection member. In the solar cell module, the plurality of solar cell elements are arranged in a matrix. A plurality of solar cell elements arranged in a straight line along one of the row direction and the column direction form a string by connecting two adjacent solar cell elements by tab wiring.

In Patent Document 1, a solar cell in which a connection layer made of a resin including a plurality of conductive particles is disposed between a tab wiring connecting two solar cell elements and a bus bar electrode formed on the surface of the solar cell element. Battery modules have been proposed.

JP 2008-135654 A

However, in the conventional solar cell module, there is a possibility that the tab wiring or the solar cell element is stressed between the solar cell elements due to the expansion and contraction of the solar cell element and the tab wiring due to the temperature cycle.

Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a solar cell module that can reduce the stress of the tab wiring and the solar cell element.

In order to solve the above problems, a solar cell module according to the present invention is arranged on two solar cell elements adjacent in a direction parallel to the light receiving surface, and on one surface and the other back surface of the two solar cell elements. A tab wiring for electrically connecting the two solar cell elements; a plurality of finger electrodes formed on the front surface and the back surface for collecting received light charges generated by the solar cell elements; and the front surface and the back surface The bus bar electrode is formed to extend in a direction intersecting with each of the plurality of finger electrodes, and electrically connects the plurality of finger electrodes, and the light receiving surface is planarized by the bus bar electrode and the tab wiring. An adhesive member for bonding the bus bar electrode and the tab wiring so as to overlap when viewed, and at least one of the front surface and the back surface , The thickness of the intersection crossing the finger electrodes of the bus bar electrode is thicker than the thickness of the portion sandwiched by the intersection adjacent the bus bar electrode.

According to the solar cell module according to the present invention, it is possible to reduce the stress of the tab wiring and the solar cell element.

1 is a schematic plan view of the solar cell module according to Embodiment 1. FIG. 2 is a plan view of the solar cell element according to Embodiment 1. FIG. FIG. 3 is a cross-sectional view illustrating a stacked structure of the solar cell element according to Embodiment 1. 4 is a structural cross-sectional view in the column direction of the solar cell module according to Embodiment 1. FIG. 5A is a structural cross-sectional view in the column direction of the solar cell element according to Embodiment 1. FIG. FIG. 5B is a structural cross-sectional view in the column direction of a conventional solar cell element. FIG. 5C is a diagram showing a modification of the structure cross section in the column direction of the solar cell element according to Embodiment 1. FIG. 6 is a plan view and a cross-sectional view showing the electrode configuration of the solar cell element according to Embodiment 1. FIG. 7 is a plan view and a cross-sectional view showing the electrode configuration of the solar cell element according to Modification 1 of Embodiment 1. FIG. 8 is a plan view and a cross-sectional view showing the electrode configuration of the solar cell element according to Modification 2 of Embodiment 1. 9A is a plan view and a cross-sectional view showing an electrode configuration of the solar cell element according to Embodiment 2. FIG. FIG. 9B is a plan view and a cross-sectional view showing an electrode configuration of a solar cell element according to Modification 1 of Embodiment 2. FIG. 9C is a plan view and a cross-sectional view showing an electrode configuration of a solar cell element according to Modification 2 of Embodiment 2. FIG. 10 is a plan view and a cross-sectional view showing an electrode configuration of a solar cell element according to Modification 3 of Embodiment 2. FIG. 11A is a plan view and a cross-sectional view showing an electrode configuration of the solar cell element according to Embodiment 3. FIG. 11B is a diagram showing an electrode formation process of a solar cell element according to a modification of Embodiment 3. FIG. 12 is a plan view and a cross-sectional view showing an electrode configuration of a solar cell element according to another embodiment. FIG. 13 is a plan view and a cross-sectional view showing an electrode configuration of a solar cell element according to another embodiment.

Hereinafter, the solar cell module according to the embodiment of the present invention will be described in detail with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement of components, connection forms, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept of the present invention are described as optional constituent elements.

Each figure is a schematic diagram and is not necessarily shown strictly. Moreover, in each figure, the same code | symbol is attached | subjected about the same structural member.

In this specification, the “front surface” of a solar cell element means a surface that allows more light to enter the interior than the “back surface” that is the opposite surface (over 50% to 100% light is the surface). And the case where no light enters the interior from the “back surface” side. The “surface” of the solar cell module means a surface on which light on the side facing the “surface” of the solar cell element can be incident, and the “back surface” means a surface on the opposite side. In addition, descriptions such as “providing the second member on the first member” do not intend only when the first and second members are provided in direct contact unless specifically limited. That is, this description includes the case where another member exists between the first and second members. In addition, the description of “substantially **” is intended to include not only exactly the same, but also those that are recognized as being substantially the same, with “substantially identical” as an example.

(Embodiment 1)
[1-1. Basic configuration of solar cell module]
An example of the basic configuration of the solar cell module according to this embodiment will be described with reference to FIG.

FIG. 1 is a schematic plan view of a solar cell module 1 according to Embodiment 1. FIG. The solar cell module 1 shown in the figure includes a plurality of solar cell elements 11, a tab wiring 20, a cross wiring 30, and a frame body 50.

The solar cell element 11 is a planar photovoltaic cell that is two-dimensionally arranged on the light receiving surface and generates electric power by light irradiation.

The tab wiring 20 is a wiring member that is disposed on the surface of the solar cell elements 11 and electrically connects the solar cell elements 11 adjacent in the column direction. The tab wiring 20 may have a light diffusion shape on the light incident side surface. The light diffusion shape is a shape having a light diffusion function. With this light diffusion shape, light incident on the tab wiring 20 can be diffused on the surface of the tab wiring 20, and the diffused light can be redistributed to the solar cell element 11.

The cross wiring 30 is a wiring member for connecting the solar cell strings. The solar cell string is an aggregate of a plurality of solar cell elements 11 arranged in the column direction and connected by the tab wiring 20. Note that a light diffusion shape may be formed on the surface of the cross wiring 30 on the light incident side. Thereby, the light incident between the solar cell element 11 and the frame body 50 is diffused on the surface of the wiring 30 and the diffused light can be redistributed to the solar cell element 11.

The frame body 50 is an outer frame member that covers the outer periphery of a panel in which a plurality of solar cell elements 11 are two-dimensionally arranged.

Although not shown, a light diffusing member may be disposed between adjacent solar cell elements 11. Thereby, since the light which entered into the clearance gap between the solar cell elements 11 can be redistributed to the solar cell element 11, the condensing efficiency of the solar cell element 11 improves. Therefore, it becomes possible to improve the photoelectric conversion efficiency of the whole solar cell module.

[1-2. Structure of solar cell element]
The structure of the solar cell element 11 which is the main component of the solar cell module 1 will be described.

FIG. 2 is a plan view of the solar cell element 11 according to the first embodiment. As shown in the figure, the solar cell element 11 has a substantially square shape in plan view. The solar cell element 11 is, for example, 125 mm long × 125 mm wide × 200 μm thick. Further, on the surface of the solar cell element 11, a plurality of striped bus bar electrodes 112 are formed in parallel to each other, and a plurality of striped finger electrodes 111 are formed in parallel to each other so as to be orthogonal to the bus bar electrodes 112. Yes. The bus bar electrode 112 and the finger electrode 111 constitute a collector electrode 110.

The collector electrode 110 can be formed by a printing method such as screen printing using a thermosetting resin-type conductive paste using a resin material as a binder and conductive particles such as silver particles as a filler, for example. .

The line width of the bus bar electrode 112 is, for example, 150 μm, the line width of the finger electrode 111 is, for example, 100 μmμ, and the pitch of the finger electrodes 111 is, for example, 2 mm. Further, the tab wiring 20 is bonded on the bus bar electrode 112.

FIG. 3 is a cross-sectional view showing the laminated structure of solar cell element 11 according to Embodiment 1. 2 is a cross-sectional view taken along the line III-III of the solar cell element 11 in FIG. As shown in FIG. 3, an i-type amorphous silicon film 121 and a p-type amorphous silicon film 122 are formed in this order on the main surface of an n-type single crystal silicon wafer 101. The n-type single crystal silicon wafer 101, the i-type amorphous silicon film 121, and the p-type amorphous silicon film 122 form a photoelectric conversion layer, and the n-type single crystal silicon wafer 101 serves as a main power generation layer. Further, the light receiving surface electrode 102 is formed on the p-type amorphous silicon film 122. As shown in FIG. 2, a collecting electrode 110 including a plurality of bus bar electrodes 112 and a plurality of finger electrodes 111 is formed on the light receiving surface electrode 102. In FIG. 3, only the finger electrode 111 of the collector electrode 110 is shown.

Also, an i-type amorphous silicon film 123 and an n-type amorphous silicon film 124 are formed in this order on the back surface of the n-type single crystal silicon wafer 101. Further, a light receiving surface electrode 103 is formed on the n-type amorphous silicon film 124, and a collecting electrode 110 including a plurality of bus bar electrodes 112 and a plurality of finger electrodes 111 is formed on the light receiving surface electrode 103.

Even if the p-type amorphous silicon film 122 is formed on the back surface side of the n-type single crystal silicon wafer 101 and the n-type amorphous silicon film 124 is formed on the light-receiving surface side of the n-type single crystal silicon wafer 101, respectively. Good.

In addition, as shown in FIG. 3, the pitch of the finger electrodes 111 on the back surface may be smaller than the pitch of the finger electrodes on the front surface. In other words, the number of finger electrodes 111 on the back surface may be larger than the number of finger electrodes on the front surface. That is, the area occupation ratio of the collector electrode formed on the back surface may be higher than the area occupation ratio of the collector electrode formed on the front surface. Here, the area occupation ratio of the collector electrode is the ratio of the total area of the bus bar electrode 112 and the finger electrode 111 in the plan view to the area of the solar cell element 11 in the plan view.

In the case of the electrode arrangement on the back surface, the current collection efficiency on the back surface increases, but the light shielding loss increases compared to the front surface. However, since the solar cell element 11 according to the present embodiment is a single-sided light receiving type in which the light receiving surface is the front surface, the effect of increasing the current collection efficiency on the back surface is more than the effect of increasing the light shielding loss on the back surface. large. Therefore, the current collection effect of the solar cell element 11 can be improved.

In order to improve the pn junction characteristics, the solar cell element 11 according to the present embodiment is provided between the n-type single crystal silicon wafer 101 and the p-type amorphous silicon film 122 or the n-type amorphous silicon film 124. The i-type amorphous silicon film 121 is provided.

The solar cell element 11 according to the present embodiment is a single-sided light receiving type, and the light receiving surface electrode 102 on the surface side of the n-type single crystal silicon wafer 101 serves as a light receiving surface. Carriers generated in the n-type single crystal silicon wafer 101 are diffused to the light-receiving surface electrodes 102 and 103 on the front surface side and the back surface side as a photocurrent and collected by the collector electrode 110.

The light-receiving surface electrodes 102 and 103 are transparent electrodes made of, for example, ITO (indium tin oxide), SnO ₂ (tin oxide), ZnO (zinc oxide), or the like. The light receiving surface electrode 103 on the back side may be a metal electrode that is not transparent. Further, as the collector electrode on the back surface side, an electrode formed on the entire surface of the light receiving surface electrode 103 may be used instead of the collector electrode 110.

Note that the solar cell element according to the present embodiment may be a double-sided light receiving type. In this case, the light receiving surface electrode 102 on the front surface side and the light receiving surface electrode 103 on the back surface side of the n-type single crystal silicon wafer 101 are light receiving surfaces. Carriers generated in the n-type single crystal silicon wafer 101 diffuse as photocurrents to the light-receiving surface electrodes 102 and 103 on the front surface side and the back surface side, and are collected by the collector electrode 110. The light receiving surface electrodes 102 and 103 are transparent electrodes.

[1-3. Structure of solar cell module]
Next, a specific structure of the solar cell module 1 according to the present embodiment will be described.

FIG. 4 is a structural cross-sectional view of the solar cell module 1 according to Embodiment 1 in the column direction. Specifically, FIG. 4 is a IV-IV cross-sectional view of the solar cell module 1 of FIG. The solar cell module 1 shown in the figure includes a solar cell element 11 having a collector electrode 110 formed on the front and back surfaces, a tab wiring 20, an adhesive member 40, a front surface filling member 70A and a back surface filling member 70B, The surface protection member 80 and the back surface protection member 90 are provided.

The tab wiring 20 is a long conductive wiring, for example, a ribbon-shaped metal foil. The tab wiring 20 can be produced by, for example, cutting a metal foil such as a copper foil or a silver foil, which is entirely covered with silver or solder, into a strip shape having a predetermined length. In the two solar cell elements 11 adjacent to each other in the column direction, the tab wiring 20 disposed on the surface of one solar cell element 11 is also disposed on the back surface of the other solar cell element 11. More specifically, the lower surface of one end portion of the tab wiring 20 is joined to the bus bar electrode 112 (see FIG. 2) on the surface side of one solar cell element 11 along the longitudinal direction of the bus bar electrode 112. Further, the upper surface of the other end portion of the tab wiring 20 is joined to the bus bar electrode on the back surface side of the other solar cell element 11 along the longitudinal direction of the bus bar electrode 112. Thereby, the solar cell string composed of a plurality of solar cell elements 11 arranged in the column direction has a configuration in which the plurality of solar cell elements 11 are connected in series in the column direction.

The tab wiring 20 and the bus bar electrode 112 (see FIG. 2) are joined by the adhesive member 40. That is, the adhesive member 40 bonds the bus bar electrode 112 and the tab wiring 20 so that the bus bar electrode 112 and the tab wiring 20 overlap when the light receiving surface is viewed in plan. Thereby, the tab wiring 20 is connected to the solar cell element 11 through the adhesive member.

As the adhesive member 40, for example, a conductive adhesive paste, a conductive adhesive film, an anisotropic conductive film, or a conductive adhesive tape can be used. The conductive adhesive paste is, for example, a paste adhesive in which conductive particles are dispersed in a thermosetting adhesive resin material such as an epoxy resin, an acrylic resin, or a urethane resin. The conductive adhesive film and the anisotropic conductive film are formed in a film shape by dispersing conductive particles in a thermosetting adhesive resin material. Further, as the adhesive member 40, it is possible to use a non-conductive adhesive. In this case, by appropriately designing the application thickness of the resin adhesive, the resin adhesive softens at the time of pressurization at the time of thermocompression bonding, and the surface of the bus bar electrode 112 and the tab wiring 20 are brought into direct contact with each other. Can be connected to.

With this configuration, the plurality of finger electrodes 111 collect light-receiving charges generated by the solar cell element 11, and the bus bar electrode 112 is formed to extend in a direction intersecting with each of the plurality of finger electrodes 111. The received light charge is transmitted to the tab wiring 20.

Moreover, as shown in FIG. 4, the surface protection member 80 is arrange | positioned at the surface side of the some solar cell element 11, and the back surface protection member 90 is arrange | positioned at the back surface side. A surface filling member 70 </ b> A is disposed between the surface including the plurality of solar cell elements 11 and the surface protection member 80, and the back surface filling is performed between the surface including the plurality of solar cell elements 11 and the back surface protection member 90. A member 70B is arranged. The front surface protection member 80 and the back surface protection member 90 are fixed by a front surface filling member 70A and a back surface filling member 70B, respectively.

The surface protection member 80 is a protection member disposed on the surface side of the solar cell element 11. The surface protection member 80 is a member that protects the inside of the solar cell module 1 from wind and rain, external impact, fire, and the like, and ensures long-term reliability of the solar cell module 1 when exposed outdoors. From this point of view, the surface protection member 80 may be, for example, a light-transmitting and water-blocking glass, a film-like or plate-shaped hard light-transmitting and water-blocking resin member, and the like.

The back surface protection member 90 is a protection member disposed on the back surface side of the solar cell element 11. The back surface protection member 90 is a member that protects the back surface of the solar cell module 1 from the external environment. For example, a resin film such as polyethylene terephthalate or a laminated film having a structure in which an Al foil is sandwiched between resin films is used. Can do.

The front surface filling member 70 </ b> A is a filler filled in the space between the plurality of solar cell elements 11 and the surface protection member 80, and the back surface filling member 70 </ b> B is formed between the plurality of solar cell elements 11 and the back surface protection member 90. It is a filler filled in the space between. The front surface filling member 70A and the back surface filling member 70B have a sealing function for shielding the solar cell element 11 from the external environment. With the arrangement of the front surface filling member 70A and the back surface filling member 70B, it is possible to ensure high heat resistance and high moisture resistance of the solar cell module 1 assumed to be installed outdoors.

The surface filling member 70A is made of a translucent polymer material having a sealing function. Examples of the polymer material of the surface filling member 70A include translucent resin materials such as ethylene vinyl acetate (EVA).

The back surface filling member 70B is made of a polymer material having a sealing function. Here, the back surface filling member 70B is processed, for example, in white. Examples of the polymer material of the back surface filling member 70B include a resin material obtained by processing EVA or the like in white.

In addition, from the viewpoint of simplification of the manufacturing process and adhesion at the interface between the surface filling member 70A and the back surface filling member 70B, the surface filling member 70A and the back surface filling member 70B are preferably the same material system. The front surface filling member 70A and the back surface filling member 70B are obtained by laminating (laminating) two resin sheets (translucent EVA sheet and white processed EVA sheet) sandwiching a plurality of solar cell elements 11 (cell strings). It is formed by doing.

[1-4. Adhesive structure between tab wiring and solar cell element]
5A is a structural cross-sectional view in the column direction of solar cell element 11 according to Embodiment 1. FIG. More specifically, FIG. 5A is an enlarged cross-sectional view of the vicinity of the surface of the solar cell element 11 in the structural cross-sectional view of FIG. As shown in the figure, the bus bar electrode 112 and the tab wiring 20 are bonded by an adhesive member 40.

FIG. 5B is a structural cross-sectional view in the column direction of a conventional solar cell element. As shown in FIG. 5B, in the conventional solar cell module, the solar cell element 11 and the tab wiring 20 are uniformly bonded over the entire area of the solar cell element 11 in the longitudinal direction of the tab wiring 20 by the adhesive member 540. ing. For this reason, when the solar cell element 11 and the tab wiring 20 are repeatedly expanded and contracted due to the temperature cycle, the tab wiring 20 or the solar cells may be stressed between the solar cells.

On the other hand, in the solar cell module 1 according to the present embodiment, the thickness of the bus bar electrode 112 at the intersection portion Px where the bus bar electrode 112 and the finger electrode 111 intersect is the bus bar sandwiched between the adjacent intersection portions Px. It is characterized by being thicker than the film thickness of the non-intersecting portion Py of the electrode 112. According to this configuration, the bus bar electrode 112 and the tab wiring 20 are closest to each other at the intersection Px and become electrically conductive, and at the non-intersection Py, the bus bar electrode 112 and the tab wiring 20 are connected via the adhesive member 40. Separate. That is, the bus bar electrode 112 and the tab wiring 20 are intermittently contacted or closest to each other in the longitudinal direction of the bus bar electrode 112. In other words, the amount (thickness) of the resin material (adhesive member 40) interposed between the bus bar electrode 112 and the tab wiring 20 in the non-intersection portion Py is between the bus bar electrode 112 and the tab wiring 20 in the intersection portion Px. The amount (thickness) is larger than the amount (thickness) of the adhesive member 40 interposed therebetween. For this reason, even if the solar cell element 11 and the tab wiring 20 repeat thermal expansion and thermal contraction, the stress generated in the longitudinal direction due to the difference in thermal expansion coefficient between the solar cell element 11 and the tab wiring 20 is not crossed. It can be relieved by the part Py. Therefore, the stress of the tab wiring 20 between the solar cell elements and the solar cell element can be reduced.

If the bus bar electrode 112 and the tab wiring 20 are electrically connected at the crossing portion Px, the received light charges generated in the solar cell element 11 and collected by the finger electrodes 111 are transmitted to the tab wiring 20. Is possible. Therefore, the bus bar electrode 112 and the tab wiring 20 may not be bonded via the bonding member 40 in the non-intersecting portion Py.

FIG. 5C is a diagram showing a modification of the structure cross section in the column direction of the solar cell element according to Embodiment 1. As shown in the figure, for example, when the adhesive member 40 is a non-conductive adhesive made of resin, the surface of the bus bar electrode 112 and the tab wiring 20 are brought into direct contact at the intersection Px. What is necessary is just to connect electrically. As a result, the bus bar electrode 112 and the tab wiring 20 are intermittently in contact with each other in the longitudinal direction of the tab wiring 20, and the solar cell element 11 and the tab wiring 20 are secured while ensuring electrical connection at the intersection Px. The stress generated in the longitudinal direction due to the difference in thermal expansion coefficient with respect to the non-intersecting portion Py can be relaxed.

In addition, the adhesive member 40 is not interposed between the bus bar electrode 112 and the tab wiring 20 in the non-intersecting portion Py, but the surface filling member 70A or the back surface filling member 70B may be interposed.

[1-5. Connection configuration between collector electrode and tab wiring according to Embodiment 1]
FIG. 6 is a plan view and a cross-sectional view showing an electrode configuration of solar cell element 11A according to Embodiment 1. More specifically, FIG. 6 is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged.

As shown in the perspective plan view of FIG. 6, a bus bar electrode 112A and a plurality of finger electrodes 111A orthogonal to the bus bar electrode 112A and parallel to each other are arranged on the surface of the solar cell element 11A. Further, an adhesive member 40 that bonds the bus bar electrode 112A and the tab wiring 20 is arranged so that the bus bar electrode 112A and the tab wiring 20 overlap when the light receiving surface is viewed in plan. In addition, although the adhesive member 40 is not illustrated in the perspective plan view of FIG. 6, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11 </ b> A, or the tab wiring 20. Is formed in a region facing the finger electrode 111A and the bus bar electrode 112A.

Here, the electrode width W1s of the finger electrode 111A at the intersecting portion Px between the bus bar electrode 112A and the finger electrode 111A is wider than the electrode width W1n of the non-intersecting portion Pz which is the other portion of the finger electrode 111A.

As described above, the finger electrode 111A and the bus bar electrode 112A are, for example, screen printed using a resin-type conductive paste that is a thermosetting type using a resin material as a binder and conductive particles such as silver particles as a filler. The printing method is used. In this case, the finger electrodes 111A and the bus bar electrodes 112A are simultaneously formed using a screen mask that allows the resin-type conductive paste to pass through the mesh pattern. For this reason, when the line width of the screen mask is relatively wide, the line width of the printed electrode is relatively wide and the film thickness can be relatively large. Here, as a method of controlling the film thickness of the electrode, for example, by adjusting the mesh of the screen plate used at the time of screen printing, and adjusting the emulsion specifications, the opening of the emulsion is narrowed or widened. For example, the paste discharge amount may be reduced or increased. As a result, it is possible to positively execute control of reducing or increasing the thickness of the electrode.

Due to the difference in electrode width (W1s> W1n) at the intersecting portion Px and the non-intersecting portion Pz of the finger electrode 111A, and the correlation between the electrode width and the film thickness by screen printing, the film thickness at the intersecting portion Px of the finger electrode 111A is The film thickness at the non-intersecting portion Pz of the finger electrode 111A is larger.

Therefore, as shown in the cross-sectional view of FIG. 6, the intersection Px of the bus bar electrode 112A is thicker than the non-intersection Py of the bus bar electrode 112A.

As described above, the tape-like or sheet-like resin material that is the adhesive member 40 is softened by being hot-pressed between the bus bar electrode 112A and the tab wiring 20, for example. Thereby, the tab wiring 20 and the bus bar electrode 112A are joined.

According to the film thickness distribution in the longitudinal direction of the bus bar electrode 112A and the bonding method using the resin material, the bus bar electrode 112A and the tab wiring 20 are in contact with or closest to each other at the intersecting portion Px, and at the non-intersecting portion Py, The bus bar electrode 112A and the tab wiring 20 are separated via the resin material.

According to the above connection configuration, even if the solar cell element 11A and the tab wiring 20 repeat thermal expansion and thermal contraction, the solar cell element 11A and the tab wiring are secured while ensuring electrical continuity between the bus bar electrode 112A and the tab wiring 20. The stress generated in the longitudinal direction can be relieved by the difference in thermal expansion coefficient with respect to 20. Therefore, compared with the case where the bus bar electrode 112A and the tab wiring 20 are joined by the adhesive member having a uniform thickness in the longitudinal direction, the stress of the tab wiring 20 and the solar cell element 11A between the solar cell elements 11A is reduced. Can be reduced.

In FIG. 6, an electrode group that extends in a direction parallel to the finger electrode 111A, intersects with the bus bar electrode 112A, and is shorter than the finger electrode 111A may be disposed between adjacent finger electrodes 111A. This electrode group is for reinforcing the adhesion between the tab wiring 20 and the solar cell element 11A, but the electrode group may be regarded as the finger electrode 111A. That is, the thickness of the bus bar electrode 112 at the intersection where the bus bar electrode 112 and the electrode group intersect may be larger than the thickness of the non-intersection of the bus bar electrode 112 sandwiched between adjacent intersections. Thereby, the stress which generate | occur | produces in the said elongate direction by the difference in the thermal expansion coefficient of the solar cell element 11 and the tab wiring 20 can be relieve | moderated by the said non-intersection part, ensuring electrical connection in the said intersection part. In the following embodiments and modifications thereof, similarly, an electrode group disposed between a plurality of finger electrodes can be regarded as finger electrodes, and the same effect can be achieved. .

Further, in FIG. 6, the length in the extending direction of the finger electrode 111 </ b> A at the intersecting portion Px may be larger or smaller than the width of the tab wiring 20. However, the length in the extending direction of the intersecting portion Px is smaller than the width of the tab wiring 20 so that the intersecting portion Px does not block the light incident on the solar cell element 11A (the intersecting portion Px covers the tab wiring 20). It is preferable that

[1-6. Configuration of connection between collector electrode and tab wiring according to modification 1 of embodiment 1]
FIG. 7 is a plan view and a cross-sectional view showing an electrode configuration of solar cell element 11B according to Modification 1 of Embodiment 1. More specifically, FIG. 7 is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged. The electrode configuration of the solar cell element 11B according to this modification is different from the electrode configuration of the solar cell element 11A shown in FIG. 6 only in the configuration of the bus bar electrode 112B. Hereinafter, the description of the same points as the electrode configuration of the solar cell element 11A shown in FIG. 6 will be omitted, and different points will be mainly described.

7, a bus bar electrode 112B and a plurality of finger electrodes 111B intersecting with the bus bar electrode 112B and parallel to each other are arranged on the surface of the solar cell element 11B. In addition, an adhesive member 40 for bonding the bus bar electrode 112B and the tab wiring 20 is arranged so that the bus bar electrode 112B and the tab wiring 20 overlap when the light receiving surface is viewed in plan. Although the adhesive member 40 is not shown in the perspective plan view of FIG. 7, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11 </ b> B, or the tab wiring 20. Is formed in a region facing the finger electrode 111B and the bus bar electrode 112B.

The bus bar electrode 112B does not have a linear shape parallel to the longitudinal direction in which the tab wiring 20 is disposed, but has a component extending in an oblique direction with respect to the longitudinal direction, and each time the bus bar electrode 112B intersects the finger electrode 111B, the oblique direction It has a zigzag shape.

Here, the electrode width W1s of the finger electrode 111B at the intersecting portion Px between the bus bar electrode 112B and the finger electrode 111B is wider than the electrode width W1n of the non-intersecting portion Pz which is the other portion of the finger electrode 111B.

The film thickness of the finger electrode 111B at the intersecting portion Px is determined by the difference in electrode width between the intersecting portion Px and the non-intersecting portion Pz of the finger electrode 111B and the correlation between the electrode width and the film thickness by screen printing. It becomes thicker than the film thickness in the non-intersecting part Pz.

Therefore, as shown in the cross-sectional view of FIG. 7, the intersection Px of the bus bar electrode 112B is thicker than the non-intersection Py of the bus bar electrode 112B.

According to the film thickness distribution in the longitudinal direction of the bus bar electrode 112B, the bus bar electrode 112B and the tab wiring 20 are in contact with or closest to each other at the intersection portion Px, and the bus bar electrode 112B and the tab wiring 20 are at the non-intersection portion Py. The resin material is interposed and separated.

According to the above connection configuration, even if the solar cell element 11B and the tab wiring 20 repeat thermal expansion and thermal contraction, the solar cell element 11B and the tab wiring are secured while ensuring electrical continuity between the bus bar electrode 112B and the tab wiring 20. The stress generated in the longitudinal direction can be relieved by the difference in thermal expansion coefficient with respect to 20. Therefore, the stress of the tab wiring 20 between the solar cell elements 11B and the solar cell element 11B can be reduced.

[1-7. Connection configuration of collector electrode and tab wiring according to modification 2 of embodiment 1]
FIG. 8 is a plan view and a cross-sectional view showing an electrode configuration of solar cell element 11C according to Modification 2 of Embodiment 1. More specifically, FIG. 8 is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged. The electrode configuration of the solar cell element 11C according to the present modification is such that the region in which the characteristic electrode configuration is formed is specified as the cell edge region as compared with the electrode configuration of the solar cell element 11A illustrated in FIG. Only the difference is. Hereinafter, the description of the same points as the electrode configuration of the solar cell element 11A shown in FIG. 6 will be omitted, and different points will be mainly described.

As shown in the perspective plan view of FIG. 8, a bus bar electrode 112C and a plurality of finger electrodes 111CC and 111CP orthogonal to the bus bar electrode 112C and parallel to each other are arranged on the surface of the solar cell element 11C. Further, an adhesive member 40 that bonds the bus bar electrode 112C and the tab wiring 20 is arranged so that the bus bar electrode 112C and the tab wiring 20 overlap when the light receiving surface is viewed in plan. Although the adhesive member 40 is not illustrated in the perspective plan view of FIG. 8, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11C, or the tab wiring 20 Is formed in a region facing the finger electrodes 111CC, 1111CP, and the bus bar electrode 112A.

The finger electrode 111CC is formed in the central region Ac of the solar cell element 11C, and the finger electrode 111CP is formed in the end region Ap of the solar cell element 11C.

Here, the electrode width W1ps of the finger electrode 111CP at the intersecting portion Px between the bus bar electrode 112C and the finger electrode 111CP is wider than the electrode width W1pn of the non-intersecting portion Pz which is the other portion of the finger electrode 111CP.

The film of the finger electrode 111CP in the intersecting portion Px of the finger electrode 111CP in the end region Ap due to the difference in the electrode width between the intersecting portion Px and the non-intersecting portion Pz and the correlation between the electrode width and the film thickness by screen printing. The thickness is greater than the film thickness at the non-intersecting portion Pz of the finger electrode 111CP.

Therefore, as shown in the cross-sectional view of FIG. 8, the intersecting portion Px of the bus bar electrode 112C in the end region Ap is thicker than the non-intersecting portion Py of the bus bar electrode 112C.

According to the film thickness distribution in the longitudinal direction of the bus bar electrode 112C, the bus bar electrode 112C and the tab wiring 20 are in contact with or closest to each other at the intersection portion Px in the end region Ap, and at the non-intersection portion Py in the end region Ap. The bus bar electrode 112C and the tab wiring 20 are separated via the resin material.

According to the above connection configuration, even if the solar cell element 11B and the tab wiring 20 repeat thermal expansion and thermal contraction, the solar cell element 11B and the tab wiring are secured while ensuring electrical continuity between the bus bar electrode 112B and the tab wiring 20. The stress generated in the longitudinal direction due to the difference in thermal expansion coefficient from 20 can be relaxed in the end region Ap of the solar cell element 11C. Therefore, particularly in the end region Ap where the tab wiring 20 is susceptible to stress, the stress on the tab wiring 20 and the solar cell element 11C between the solar cell elements 11C can be more effectively reduced.

(Embodiment 2)
In the solar cell module according to the present embodiment, as in the solar cell module 1 according to the first embodiment, the intersecting portion Px that intersects the finger electrode of the bus bar electrode is thicker than the non-intersecting portion Py of the bus bar electrode. And In order to realize this, in the first embodiment, the electrode width W1s of the finger electrode 111A at the intersecting portion Px is made wider than the electrode width W1n of the non-intersecting portion Pz of the finger electrode 111A. On the other hand, in the present embodiment, the electrode width of the bus bar electrode is made narrower than the electrode width of the finger electrode.

Since the basic configuration and the like of the solar cell module according to the present embodiment are the same as those according to the first embodiment, description thereof will be omitted, and hereinafter, the electrode configuration and the cross-sectional structure of the solar cell element 11D different from the first embodiment The explanation will be focused on.

[2-1. Connection configuration between collector electrode and tab wiring according to second embodiment]
FIG. 9A is a plan view and a cross-sectional view showing an electrode configuration of solar cell element 11D according to Embodiment 2. More specifically, FIG. 9A is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged.

As shown in the perspective plan view of FIG. 9A, a bus bar electrode 112D and a plurality of finger electrodes 111D orthogonal to the bus bar electrode 112D and parallel to each other are arranged on the surface of the solar cell element 11D. Further, an adhesive member 40 that bonds the bus bar electrode 112D and the tab wiring 20 is arranged so that the bus bar electrode 112D and the tab wiring 20 overlap when the light receiving surface is viewed in plan. Although the adhesive member 40 is not shown in the perspective plan view of FIG. 9A, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11D, or the tab wiring 20 Is formed in a region facing the finger electrode 111D and the bus bar electrode 112D.

Here, the electrode width W2n of the bus bar electrode 112D is narrower than the electrode width W1n of the finger electrode 111D.

The finger electrode 111D and the bus bar electrode 112D can be formed by a printing method such as screen printing, for example. In this case, the finger electrodes 111D and the bus bar electrodes 112D are simultaneously formed using a screen mask that allows the resin-type conductive paste to pass through the mesh pattern. For this reason, when the line width of the screen mask is relatively wide, the line width of the printed electrode is relatively wide and the film thickness is also relatively thick.

Due to the difference in electrode width between the bus bar electrode 112D and the finger electrode 111D and the correlation between the electrode width and the film thickness obtained by screen printing, the film thickness of the finger electrode 111D is larger than the film thickness of the bus bar electrode 112D.

Therefore, as shown in the cross-sectional view of FIG. 9A, the intersecting portion Px of the bus bar electrode 112D is thicker than the non-intersecting portion Py of the bus bar electrode 112D.

As described above, the tape-like or sheet-like resin material that is the adhesive member 40 is softened by being hot-pressed between the bus bar electrode 112D and the tab wiring 20, for example. Thereby, the tab wiring 20 and the bus bar electrode 112D are joined.

According to the film thickness distribution in the longitudinal direction of the bus bar electrode 112D and the bonding method using the resin material, the bus bar electrode 112D and the tab wiring 20 are in contact with or closest to each other at the intersecting portion Px, and at the non-intersecting portion Py, The bus bar electrode 112D and the tab wiring 20 are separated via the resin material.

According to the above connection configuration, even if the solar cell element 11D and the tab wiring 20 repeat thermal expansion and thermal contraction, the solar cell element 11D and the tab wiring are secured while ensuring electrical continuity between the bus bar electrode 112D and the tab wiring 20. The stress generated in the longitudinal direction can be relieved by the difference in thermal expansion coefficient with respect to 20. Therefore, compared to the case where the bus bar electrode 112D and the tab wiring 20 are joined by the adhesive member having a uniform thickness in the longitudinal direction, the stress of the tab wiring 20 and the solar cell element 11D between the solar cell elements 11D is reduced. Can be reduced.

[2-2. Configuration of connection between collector electrode and tab wiring according to Modification 1 of Embodiment 2]
FIG. 9B is a plan view and a cross-sectional view showing an electrode configuration of a solar cell element according to Modification 1 of Embodiment 2. More specifically, FIG. 9B is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged. The electrode configuration of the solar cell element 11H according to the present modification is different from the electrode configuration of the solar cell element 11D shown in FIG. 9A in that the characteristic electrode configuration is different between the cell end region and the cell center region. Is different. Hereinafter, the description of the same points as the electrode configuration of the solar cell element 11D shown in FIG. 9A will be omitted, and different points will be mainly described.

9B, a bus bar electrode 112H and a plurality of finger electrodes 111HC and 111HP orthogonal to the bus bar electrode 112H and parallel to each other are arranged on the surface of the solar cell element 11H. In addition, an adhesive member 40 for bonding the bus bar electrode 112H and the tab wiring 20 is disposed so that the bus bar electrode 112H and the tab wiring 20 overlap when the light receiving surface is viewed in plan. In addition, although the adhesive member 40 is not illustrated in the perspective plan view of FIG. 9B, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11H, or the tab wiring 20 Is formed in a region facing the finger electrodes 111HC, 1111HP, and the bus bar electrode 112H.

The finger electrode 111HC is formed in the central region Ac of the solar cell element 11H, and the finger electrode 111HP is formed in the end region Ap of the solar cell element 11H.

Here, the electrode width W1np of the finger electrode 111HP is wider than the electrode width W1nc of the finger electrode 111HC.

Due to the difference between the electrode widths of the finger electrodes 111HP and 111HC and the correlation between the electrode width by screen printing and the film thickness, the electrode film thickness at the intersection Pxp between the finger electrode 111HP and the bus bar electrode 112H in the end region Ap is It becomes thicker than the electrode film thickness at the intersection Pxc between the finger electrode 111HC and the bus bar electrode 112H in the central region Ac.

When the tab wiring 20 is bonded to the bus bar electrode 112H having the above electrode film thickness relationship, a cross-sectional structure as shown in the cross-sectional view of FIG. 9B is obtained. That is, the distance between the tab wiring 20 and the bus bar electrode 112H in the non-intersection portion Pyp between the finger electrode 111HP and the bus bar electrode 112H in the end region Ap is the non-intersection portion Pyc between the finger electrode 111HC and the bus bar electrode 112H in the central region Ac. The distance between the tab wiring 20 and the bus bar electrode 112H in FIG.

In the lower part of FIG. 9B, a cross-sectional view of the non-intersecting portions Pyp and Pyc cut along the extending direction of the finger electrodes is shown. Here, (1) the distance between the tab wiring 20 and the bus bar electrode 112H in the non-intersection portion Pyp is larger than the distance between the tab wiring 20 and the bus bar electrode 112H in the non-intersection portion Pyc, and (2) the non-intersection portion. Since the cross-sectional area Sp of the adhesive member 40 at Pyp and the cross-sectional area Sc of the adhesive member 40 at the non-intersecting portion Pyc are equal, the adhesive width in the extending direction between the tab wiring 20 and the adhesive member 40 at the non-intersecting portion Pyp. Wp40 is narrower than the bonding width Wc40 in the extending direction between the tab wiring 20 and the bonding member 40 in the non-intersecting portion Pyc.

Therefore, the adhesive strength between the tab wiring 20 and the bus bar electrode 112H in the non-intersecting portion Pyp in the end region Ap is lower than the adhesive strength between the tab wiring 20 and the bus bar electrode 112H in the non-intersecting portion Pyc in the end region Ac. .

According to the above-described bonding structure between the tab wiring 20 and the bus bar electrode 112H, the bus bar electrode 112H and the tab wiring 20 are in contact with or closest to each other at the intersecting portions Pxp and Pxc, and the bus bar electrode 112H and the tab at the non-intersecting portions Pyp and Pyc. It is separated from the wiring 20 via the resin material. Furthermore, the non-crossing portion Pyp has a lower adhesive strength than the non-crossing portion Pyc.

According to the above connection configuration, even if the solar cell element 11H and the tab wiring 20 repeat thermal expansion and thermal contraction, the solar cell element 11H and the tab wiring are secured while ensuring electrical continuity between the bus bar electrode 112H and the tab wiring 20. The stress generated in the longitudinal direction due to the difference in thermal expansion coefficient from 20 can be relaxed in the end region Ap of the solar cell element 11H. Therefore, particularly in the end region Ap where the tab wiring 20 is susceptible to stress, the stress on the tab wiring 20 and the solar cell element 11H between the solar cell elements 11H can be more effectively reduced.

[2-3. Connection configuration of collector electrode and tab wiring according to modification 2 of embodiment 2]
FIG. 9C is a plan view and a cross-sectional view showing an electrode configuration of a solar cell element according to Modification 2 of Embodiment 2. More specifically, FIG. 9C is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged. The electrode configuration of the solar cell element 11J according to this modification is different from that of the solar cell element 11D shown in FIG. 9A in that the characteristic electrode configuration is different between the cell edge region and the cell central region. Is different. Hereinafter, the description of the same points as the electrode configuration of the solar cell element 11D shown in FIG. 9A will be omitted, and different points will be mainly described.

As shown in the perspective plan view of FIG. 9C, on the surface of the solar cell element 11J, bus bar electrodes 112JC and 112JP and a plurality of finger electrodes 111J orthogonal to and parallel to the bus bar electrodes 112JC or 112JP are arranged. Further, an adhesive member 40 for bonding the bus bar electrodes 112JC and 112JP and the tab wiring 20 is arranged so that the bus bar electrodes 112JC and 112JP and the tab wiring 20 overlap when the light receiving surface is viewed in plan. Although the adhesive member 40 is not shown in the perspective plan view of FIG. 9C, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11J, or the tab wiring 20 Is formed in a region facing the finger electrode 111J and the bus bar electrodes 112JC and 112JP.

The bus bar electrode 112JC is formed in the central region Ac of the solar cell element 11J, and the bus bar electrode 112JP is formed in the end region Ap of the solar cell element 11J.

Here, the electrode width W2np of the bus bar electrode 112JP is narrower than the electrode width W2nc of the bus bar electrode 112JC.

Due to the difference between the electrode widths of the bus bar electrodes 112JC and 112JP and the correlation between the electrode width and the film thickness by screen printing, the electrode film thickness at the intersection Pxp between the finger electrode 111J and the bus bar electrode 112JP in the end region Ap is It becomes thinner than the electrode film thickness at the intersection Pxc between the finger electrode 111J and the bus bar electrode 112JC in the central region Ac. In addition, the electrode film thickness in the non-intersection portion Pyp between the finger electrode 111J and the bus bar electrode 112JP in the end region Ap is thinner than the electrode film thickness in the non-intersection portion Pyc between the finger electrode 111J and the bus bar electrode 112JC in the center region Ac. Become.

When the tab wiring 20 is bonded to the bus bar electrodes 112JC and 112JP having the above electrode film thickness relationship, a cross-sectional structure as shown in the cross-sectional view of FIG. 9C is obtained.

In the lower part of FIG. 9C, a cross-sectional view in which the non-intersecting portions Pyp and Pyc are cut in the extending direction of the finger electrodes is shown. Here, (1) the cross-sectional area of the bus bar electrode 112JP at the non-intersecting portion Pyp is smaller than the cross-sectional area of the bus bar electrode 112JC at the non-intersecting portion Pyp, and (2) the cross-sectional area of the adhesive member 40 at the non-intersecting portion Pyp. Since Sp and the cross-sectional area Sc of the adhesive member 40 in the non-intersecting portion Pyc are equal, the adhesive width Wp40 in the extending direction between the tab wiring 20 and the adhesive member 40 in the non-intersecting portion Pyp is equal to that in the non-intersecting portion Pyc. It becomes narrower than the bonding width Wc40 of the tab wiring 20 and the adhesive member 40 in the extending direction.

Therefore, the adhesive strength between the tab wiring 20 and the bus bar electrode 112JP in the non-intersecting portion Pyp of the end region Ap is lower than the adhesive strength between the tab wiring 20 and the bus bar electrode 112JC in the non-intersecting portion Pyc of the end region Ac. .

According to the above-described bonding structure between the tab wiring 20 and the bus bar electrodes 112JC and 112JP, the bus bar electrodes 112JP and 112JC and the tab wiring 20 are in contact with or closest to each other at the intersections Pxp and Pxc, and at the non-intersections Pyp and Pyc The electrodes 112JP and 112JC and the tab wiring 20 are separated via the resin material. Furthermore, the non-crossing portion Pyp has a lower adhesive strength than the non-crossing portion Pyc.

According to the connection configuration described above, even if the solar cell element 11J and the tab wiring 20 repeat thermal expansion and thermal contraction, the bus bar electrodes 112JC and 112JP and the tab wiring 20 are secured to the solar cell element 11J while ensuring electrical continuity. The stress generated in the longitudinal direction due to the difference in thermal expansion coefficient with the tab wiring 20 can be relaxed in the end region Ap of the solar cell element 11J. Therefore, particularly in the end region Ap where the tab wiring 20 is susceptible to stress, the stress of the tab wiring 20 and the solar cell element 11J between the solar cell elements 11J can be more effectively reduced.

[2-4. Connection configuration of collector electrode and tab wiring according to modification 3 of embodiment 2]
FIG. 10 is a plan view and a cross-sectional view showing an electrode configuration of solar cell element 11E according to Modification 3 of Embodiment 2. More specifically, FIG. 10 is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged. The electrode configuration of the solar cell element 11E according to the present modification is different from the electrode configuration of the solar cell element 11D shown in FIG. 9A only in the arrangement configuration of the bus bar electrodes 112E. Hereinafter, the description of the same points as the electrode configuration of the solar cell element 11D shown in FIG. 9A will be omitted, and different points will be mainly described.

As shown in the perspective plan view of FIG. 10, a bus bar electrode 112E and a plurality of finger electrodes 111E intersecting the bus bar electrode 112E and parallel to each other are arranged on the surface of the solar cell element 11E. Further, an adhesive member 40 that bonds the bus bar electrode 112E and the tab wiring 20 is arranged so that the bus bar electrode 112E and the tab wiring 20 overlap when the light receiving surface is viewed in plan. Note that the adhesive member 40 is not shown in the perspective plan view of FIG. 10, but the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11E, or the tab wiring 20 Is formed in a region facing the finger electrode 111E and the bus bar electrode 112E.

The bus bar electrode 112E is formed of two wirings extending in the longitudinal direction in which the tab wiring 20 is arranged and parallel to each other.

Here, the electrode width W2n of each of the two wires forming the bus bar electrode 112E is wider than the electrode width W1n of the finger electrode 111E.

Due to the difference in electrode width between the wiring that forms the bus bar electrode 112E and the finger electrode 111E, and the correlation between the electrode width and the film thickness by screen printing, the thickness of the finger electrode 111E is the same as that of the wiring that forms the bus bar electrode 112E. It becomes thicker than the film thickness.

Therefore, as shown in the cross-sectional view of FIG. 10, the intersecting portion Px of the bus bar electrode 112E is thicker than the non-intersecting portion Py of the bus bar electrode 112E.

According to the film thickness distribution in the longitudinal direction of the bus bar electrode 112E, the bus bar electrode 112E and the tab wiring 20 are in contact with or closest to each other at the intersection portion Px, and the bus bar electrode 112E and the tab wiring 20 are at the non-intersection portion Py. The resin material is interposed and separated.

Furthermore, the electrical conductivity of the bus bar electrode 112E can be improved by arranging a plurality of wirings for forming the bus bar electrode 112E by an amount corresponding to the electrode width of the bus bar electrode 112E being narrower than the electrode width of the finger electrode 111E.

According to the above connection configuration, even when the solar cell element 11E and the tab wiring 20 repeat thermal expansion and thermal contraction, the electrical connection between the bus bar electrode 112E and the tab wiring 20 is ensured, and the conductivity of the bus bar electrode 112E is improved. The stress generated in the longitudinal direction can be relieved by the difference in thermal expansion coefficient between the solar cell element 11E and the tab wiring 20. Therefore, the stress of the tab wiring 20 between the solar cell elements 11E and the solar cell element 11E can be reduced.

(Embodiment 3)
[3-1. Connection configuration of collector electrode and tab wiring according to Embodiment 3]
FIG. 11A is a plan view and a cross-sectional view showing an electrode configuration of solar cell element 11F according to Embodiment 3. More specifically, FIG. 11A is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged.

As shown in the perspective plan view of FIG. 11A, a bus bar electrode 112F and a plurality of finger electrodes 111F orthogonal to the bus bar electrode 112F and parallel to each other are arranged on the surface of the solar cell element 11F. In addition, an adhesive member 40 for bonding the bus bar electrode 112F and the tab wiring 20 is disposed so that the bus bar electrode 112F and the tab wiring 20 overlap when the light receiving surface is viewed in plan. In addition, although the adhesive member 40 is not illustrated in the perspective plan view of FIG. 11A, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11F, or the tab wiring 20 Is formed in a region facing the finger electrode 111F and the bus bar electrode 112F.

Here, the film thickness t1n of the plurality of finger electrodes 111F is thicker than the film thickness t2n of the bus bar electrode 112F.

The finger electrode 111F and the bus bar electrode 112F can be formed by a printing method such as screen printing, for example. In this case, the finger electrode 111F and the bus bar electrode 112F are simultaneously formed using a screen mask that allows the resin-type conductive paste to pass through the mesh pattern. In the present embodiment, screen printing is performed a plurality of times when the finger electrode 111F and the bus bar electrode 112F are formed. For example, the bus bar electrode 112F and the first finger electrode 111F1 are formed by the first screen printing. Thereafter, in the second screen printing, the electrode layer is not formed on the bus bar electrode 112F, and the second finger electrode 111F2 is formed only on the first finger electrode 111F1.

The film thickness of the finger electrode 111F is larger than the film thickness of the bus bar electrode 112F without increasing the electrode width of the finger electrode relative to the bus bar electrode by the above manufacturing method. Therefore, it is possible to reduce the light-shielding loss as compared with the case where the electrode width of the finger electrode is relatively wide with respect to the bus bar electrode.

Therefore, as shown in the cross-sectional view of FIG. 11A, the intersecting portion Px of the bus bar electrode 112F is thicker than the non-intersecting portion Py of the bus bar electrode 112F.

As described above, the tape-like or sheet-like resin material that is the adhesive member 40 is softened by being hot-pressed between the bus bar electrode 112F and the tab wiring 20, for example. Thereby, the tab wiring 20 and the bus bar electrode 112F are joined.

According to the film thickness distribution in the longitudinal direction of the bus bar electrode 112F and the bonding method using the resin material, the bus bar electrode 112F and the tab wiring 20 are in contact with or closest to each other at the intersection portion Px, and at the non-intersection portion Py, The bus bar electrode 112F and the tab wiring 20 are separated via the resin material.

According to the above connection configuration, even if the solar cell element 11F and the tab wiring 20 repeat thermal expansion and thermal contraction, while ensuring electrical continuity between the bus bar electrode 112F and the tab wiring 20, and reducing light shielding loss, The stress generated in the long direction can be relaxed. Therefore, compared with the case where the bus bar electrode 112F and the tab wiring 20 are joined by the adhesive member having a uniform thickness in the longitudinal direction, the stress of the tab wiring 20 and the solar cell element 11F between the solar cell elements 11F is reduced. Can be reduced.

[3-2. Collector Electrode Formation Process According to Modification of Embodiment 3]
In this modification, a screen printing method having steps different from those of the collector electrode screen printing method described in the third embodiment will be described.

FIG. 11B is a diagram showing an electrode forming process of solar cell element 11K according to a modification of Embodiment 3. The electrode configuration when the solar cell element 11K is viewed in plan is the same as the electrode configuration when the solar cell element 11F according to Embodiment 3 is viewed in plan.

As shown in FIG. 11B, a bus bar electrode 112K and a plurality of finger electrodes 111K1 and 111K2 orthogonal to the bus bar electrode 112K and parallel to each other are arranged on the surface of the solar cell element 11K. The plurality of finger electrodes 111K1 are, for example, finger electrodes arranged at odd numbers among all finger electrodes, and the plurality of finger electrodes 111K2, for example, are fingers arranged at even numbers among all finger electrodes. Electrode.

Here, as shown in the AA sectional view of FIG. 11B, the electrode film thickness at the intersection of the plurality of finger electrodes 111K2 and the bus bar electrode 112K is larger than the electrode film thickness of the plurality of finger electrodes 111K1 and the bus bar electrode 112K. thick.

The finger electrodes 111K1 and 111K2 and the bus bar electrode 112K can be formed by a printing method such as screen printing, for example. In this case, the finger electrodes 111K1 and 111K2 and the bus bar electrode 112K are simultaneously formed using a screen mask that allows the resin-type conductive paste to pass through the mesh pattern. In this modification, screen printing is performed a plurality of times when the finger electrodes 111K1 and 111K2 and the bus bar electrode 112K are formed. For example, the bus bar electrode 112K and the finger electrode 111K1 are formed by the first screen printing. Thereafter, finger electrodes 111K2 are formed by the second screen printing.

With the above manufacturing method, the film thickness of the intersections of the plurality of finger electrodes 111K2 and the bus bar electrodes 112K is the film of the bus bar electrodes 112K and the finger electrodes 111K without increasing the electrode width of the finger electrodes relative to the bus bar electrodes. It becomes thicker than the thickness.

Therefore, it is possible to reduce the light shielding loss as compared with the case where the electrode width of the finger electrode is relatively wide with respect to the bus bar electrode.

The thus-formed solar cell element 11K is thermocompression bonded with a tape-like or sheet-like resin material as the adhesive member 40 sandwiched between the bus bar electrode 112K and the tab wiring 20. Thereby, the tab wiring 20 and the bus bar electrode 112K are joined.

According to the film thickness distribution in the longitudinal direction of the bus bar electrode 112K and the bonding method using the resin material, the bus bar electrode 112K and the tab wiring 20 are in contact with each other or recently at the intersection of the finger electrode 111K2 and the bus bar electrode 112K. In other portions, the bus bar electrode 112K and the tab wiring 20 are separated via the resin material.

According to the above connection configuration, even if the solar cell element 11K and the tab wiring 20 repeat thermal expansion and thermal contraction, the electrical conduction between the bus bar electrode 112K and the tab wiring 20 is ensured, and the light shielding loss is reduced. The stress generated in the long direction can be relaxed. Therefore, compared with the case where the bus bar electrode 112K and the tab wiring 20 are joined by the adhesive member having a uniform thickness in the longitudinal direction, the stress of the tab wiring 20 and the solar cell element 11K between the solar cell elements 11K is reduced. Can be reduced.

In addition, in the electrode formation process of the solar cell element according to Embodiment 3 and the modification thereof, as a material of the conductive paste to be used, for example, a conductive paste containing at least one of Ag, Cu, and Ni, Ag coating Examples thereof include a conductive paste containing conductive particles such as Ni powder or Ag-coated Cu powder. Note that the material of the conductive paste used may not be the same for the first screen printing and the second screen printing. For example, in the first screen printing in which a bus bar electrode and a finger electrode (a part thereof) are formed, a conductive paste material (Ag paste) having a low resistivity is used in preference to the current collection efficiency, In the second screen printing in which only part is formed, a conductive paste material (conductive paste containing Ag-coated Ni powder or Ag-coated Cu powder, etc.) having a relatively high resistivity and low cost in consideration of cost is used. It may be used.

(Other embodiments)
As described above, the solar cell module according to the present invention has been described based on Embodiments 1 to 3 and their modifications. However, the present invention is not limited to the above-described embodiments and their modifications. .

For example, in the first to third embodiments and the modifications thereof, the solar cell elements 11 and 11A to 11K only have to have a function as a photovoltaic power, and are not limited to the structure of the solar cell element.

Further, in Embodiments 1 to 3 and the modifications thereof, the electrode configuration having the characteristics as described above is shown as being applied to the surface of the solar cell element. However, the electrode configuration having the characteristics described above is described below. Moreover, it may be applied only to the back surface of the solar cell element or to both the front surface and the back surface.

Further, the bus bar electrode and the finger electrode may not be a straight line but may be a curved line.

In the solar cell module according to the above embodiment, a configuration in which a plurality of solar cell elements are arranged in a matrix on the surface is shown, but the configuration is not limited to the matrix arrangement. For example, the structure arrange | positioned at annular | circular shape arrangement | positioning, the one-dimensional linear form, or the curve form may be sufficient.

In addition, embodiments obtained by applying various modifications conceived by those skilled in the art to the above-described first to third embodiments and modifications thereof, and the first to third embodiments and modifications thereof without departing from the spirit of the present invention Embodiments realized by arbitrarily combining the components and functions in the examples are also included in the present invention.

In addition, the following electrode structure is mentioned as a solar cell module which concerns on other embodiment. Since the basic configuration and the like of the solar cell module according to the present embodiment are the same as those according to the first to third embodiments, the description thereof will be omitted. Hereinafter, the electrode configuration of the solar cell element 11G different from that of the first embodiment and The cross-sectional structure will be mainly described.

FIG. 12 is a plan view and a cross-sectional view showing an electrode configuration of a solar cell element 11G according to another embodiment.

As shown in the perspective plan view of FIG. 12, on the surface of the solar cell element 11G, two parallel bus bar electrodes 112G and a plurality of finger electrodes 111G orthogonal to the bus bar electrodes 112G and parallel to each other are arranged. . However, the adhesive member 40 that bonds the finger electrode 111G and the tab wiring 20 is arranged so that the two bus bar electrodes 112G and the tab wiring 20 do not overlap when the light receiving surface is viewed in plan. In addition, although the adhesive member 40 is not illustrated in the perspective plan view of FIG. 12, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11G or the tab wiring 20. Is formed in a region facing the finger electrode 111G.

As described above, the tape-like or sheet-like resin material that is the adhesive member 40 is softened by being hot-pressed between the finger electrode 111G and the tab wiring 20, for example. Thereby, the tab wiring 20 and the finger electrode 111G are joined.

By joining the tab wiring 20 and the finger electrode 111G with the above resin material, the finger electrode 111G and the tab wiring 20 are in contact with or closest to each other in the overlapping portion between the tab wiring 20 and the finger electrode 111G, and in the non-overlapping portion, The tab wiring 20 and the surface of the solar cell element 11G are separated via the resin material. In addition, if the finger electrode 111G and the tab wiring 20 are electrically connected at the overlapping portion, the received light charges generated in the solar cell element 11G and collected by the finger electrode 111G are transmitted to the tab wiring 20. Is possible. For this reason, in the non-overlapping portion, the surface of the solar cell element 11 </ b> G and the tab wiring 20 may not be bonded via the bonding member 40.

According to the above connection configuration, even when the solar cell element 11G and the tab wiring 20 repeat thermal expansion and thermal contraction, the solar cell element 11G and the tab wiring are secured while ensuring electrical continuity between the finger electrode 111G and the tab wiring 20. The stress generated in the longitudinal direction of the tab wiring 20 can be relieved by the difference in thermal expansion coefficient from that of the tab wiring 20. Therefore, the stress of the tab wiring 20 between the solar cell elements 11G and the solar cell element 11G can be reduced as compared with the case where the bus bar electrode and the tab wiring are joined by the adhesive member having a uniform thickness in the longitudinal direction. .

In FIG. 12, the bus bar electrode 112G may not be formed.

FIG. 13 is a plan view and a cross-sectional view showing an electrode configuration of a solar cell element 11L according to another embodiment.

As shown in the perspective plan view of FIG. 13, there are no bus bar electrodes on the surface of the solar cell element 11L, and a plurality of finger electrodes 111G parallel to each other are arranged. As shown in the cross-sectional view of FIG. 13, an adhesive member 40 that bonds the plurality of finger electrodes 111 </ b> G and the tab wiring 20 is disposed. Although the adhesive member 40 is not shown in the perspective plan view of FIG. 13, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11L, or the tab wiring 20 Is formed in a region facing the finger electrode 111G.

By joining the tab wiring 20 and the finger electrode 111G with the above resin material, the finger electrode 111G and the tab wiring 20 are in contact with or closest to each other in the overlapping portion between the tab wiring 20 and the finger electrode 111G, and in the non-overlapping portion, The tab wiring 20 and the surface of the solar cell element 11L are separated via the resin material. According to the above connection configuration, even if the solar cell element 11L and the tab wiring 20 repeat thermal expansion and thermal contraction, the solar cell element 11L and the tab wiring are secured while ensuring electrical continuity between the finger electrode 111G and the tab wiring 20. The stress generated in the longitudinal direction of the tab wiring 20 can be relieved by the difference in thermal expansion coefficient from that of the tab wiring 20. Therefore, the stress of the tab wiring 20 between the solar cell elements 11L and the solar cell element 11L can be reduced as compared with the case where the bus bar electrode and the tab wiring are joined by the adhesive member having a uniform thickness in the longitudinal direction. .

Furthermore, in addition to the electrode configuration of the solar cell element 11L described in FIG. 13, the electrode width of the finger electrode 111G in the end region Ap is equal to the finger electrode 111G in the central region Ac as in the configuration of the finger electrode shown in FIG. 9B. The electrode width of the finger electrode 111G in the end region Ap may be greater than the thickness of the finger electrode 111G in the central region Ac.

When the tab wiring 20 is bonded to the finger electrode 111G having the relationship of the electrode film thickness, the distance between the tab wiring 20 and the surface of the solar cell element in the non-overlapping portion of the end region Ap is the center region Ac. It becomes larger than the distance between the tab wiring 20 and the solar cell element surface in the non-overlapping portion.

Therefore, the adhesive strength between the tab wiring 20 and the solar cell element in the non-overlapping portion of the end region Ap is lower than the adhesive strength between the tab wiring 20 and the solar cell element in the non-overlapping portion of the end region Ac. .

According to the above connection configuration, even if the solar cell element 11L and the tab wiring 20 repeat thermal expansion and thermal contraction, the solar cell element 11L and the tab wiring are secured while ensuring electrical continuity between the finger electrode 111G and the tab wiring 20. The stress generated in the longitudinal direction due to the difference in thermal expansion coefficient from 20 can be relaxed in the end region Ap of the solar cell element 11L. Therefore, particularly in the end region Ap where the tab wiring 20 is susceptible to stress, the stress of the tab wiring 20 and the solar cell element 11L between the solar cell elements 11L can be more effectively reduced.

DESCRIPTION OF SYMBOLS 1 Solar cell module 11, 11A, 11B, 11C, 11D, 11E, 11F, 11G, 11H, 11J, 11K, 11L Solar cell element 20 Tab wiring 40 Adhesive member 111, 111A, 111B, 111C, 111CC, 111CP, 111D, 111E, 111F, 111F1, 111F2, 111G, 111HC, 111HP, 111J, 111K1, 111K2 Finger electrode 112, 112A, 112B, 112C, 112D, 112E, 112F, 112G, 112H, 112JC, 112JP, 112K Busbar electrode

Claims (9)

1. Two solar cell elements adjacent in a direction parallel to the light receiving surface;
   Tab wiring arranged on one surface and the other back surface of the two solar cell elements to electrically connect the two solar cell elements;
   A plurality of finger electrodes that are formed on the front surface and the back surface and collect light-receiving charges generated by a solar cell element;
   A bus bar electrode that is formed to extend in a direction intersecting each of the plurality of finger electrodes on the front surface and the back surface, and electrically connecting the plurality of finger electrodes;
   An adhesive member for bonding the bus bar electrode and the tab wiring so that the bus bar electrode and the tab wiring overlap when the light receiving surface is viewed in plan,
   In at least one of the front surface and the back surface, the film thickness of the intersecting portion that intersects the finger electrode of the bus bar electrode is larger than the film thickness of the portion sandwiched between the intersecting portions adjacent to the bus bar electrode. .
2. The solar cell module according to claim 1, wherein an electrode width of the finger electrode at the intersecting portion is wider than an electrode width of another portion of the finger electrode.
3. The solar cell module according to claim 1, wherein an electrode width of the bus bar electrode is narrower than an electrode width of the finger electrode.
4. The solar cell module according to claim 1, wherein a film thickness of the plurality of finger electrodes is thicker than a film thickness of the bus bar electrode.
5. The film thickness of the intersecting portion of the bus bar electrode in at least one end region of the front surface and the back surface is greater than the film thickness of the portion sandwiched between the adjacent intersecting portions of the bus bar electrode. 5. The solar cell module according to any one of 4 above.
6. In only the end region of at least one of the center region and the end region of the front surface and the back surface, the thickness of the intersecting portion of the bus bar electrode is a portion sandwiched between the intersecting portions adjacent to the bus bar electrode The solar cell module according to claim 5, wherein the solar cell module is thicker than the thickness of the solar cell module.
7. The adhesive member is a resin,
   The solar cell module according to any one of claims 1 to 6, wherein the resin is interposed between the bus bar electrode and the tab wiring.
8. The solar cell module according to claim 7, wherein the bus bar electrode and the tab wiring are in intermittent contact with each other in the direction.
9. Two solar cell elements adjacent in a direction parallel to the light receiving surface;
   Tab wiring arranged on one surface and the other back surface of the two solar cell elements to electrically connect the two solar cell elements;
   A plurality of finger electrodes that are formed on the front surface and the back surface and collect light-receiving charges generated by a solar cell element;
   An adhesive member for bonding the plurality of finger electrodes and the tab wiring so that the plurality of finger electrodes and the tab wiring intersect when the light receiving surface is viewed in plan,
   The electrode width of the finger electrode in the end region is wider than the electrode width of the finger electrode in the center region in the central region and the end region of at least one of the front surface and the back surface, or the finger electrode in the end region Is thicker than the thickness of the finger electrode in the central region,
   Solar cell module.

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