JP2011210747A - Solar cell module and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique preventing the crack of a solar cell element by suppressing a stress concentration to the solar cell element.SOLUTION: In a solar cell module, at least one conductive land is formed on a plate-shaped substrate, and the solar cell element is arranged while directing the second electrode of the plate-shaped solar cell element mounting a first electrode on one surface and mounting the second electrode on the other surface towards the conductive land of the substrate. In the solar cell module, when a light non-receiving side electrode and the conductive land are connected while partially interposing connections between the second electrode of the solar cell element and the conductive land on the substrate, an opening between the second electrode of the solar cell element and the conductive land generated by the interposition of the connections is set in 100 μm or less.

Description

  The present invention relates to a solar cell module and a manufacturing method thereof.

  As solar cells, for example, those using single crystal silicon or polycrystalline silicon are widely known.

  In solar cells using these crystalline silicon, the silicon is transparently strengthened because it may cause deterioration of power generation characteristics due to chemical changes when silicon is exposed, and may be damaged by physical impact. Solar cell modules protected with glass or the like are used.

  In addition, since the electric power obtained from one cell (also referred to as a solar cell element) of the solar cell is small, a string in which the solar cell elements are connected in series or a matrix in which this string is further connected in parallel is used to obtain a desired electric power. It is general to be configured so that For this reason, when a solar cell element is modularized, it laminates in the state which used the solar cell element as the string or the matrix.

  FIG. 13 is a diagram showing a connection example of a conventional solar cell element, and FIG. 14 is a schematic diagram of a conventional solar cell module.

  As shown in FIG. 13, the solar cell element 1 has a pn junction formed by diffusing phosphorus on one surface of a p-type silicon wafer 1s, and an upper electrode (surface) on the surface (light-receiving surface) on which the pn junction is formed. An electrode) 1f is provided, and a lower electrode (back electrode) 1b is provided on the back surface (non-light-receiving surface) of the p-type silicon wafer 1s.

With the above configuration, the solar cell element 1 receives light on the light receiving surface to generate electric power between the upper electrode 1f and the lower electrode 1b, and the upper electrode 1f is a negative electrode and the lower electrode 1b is a positive electrode. The lower electrode 1b of the solar cell element 1 and the upper electrode 1f of the adjacent solar cell element 1 are connected by soldering the ribbon wire 2, and the lower electrode 1b of the adjacent solar cell 1 and the adjacent sun The string 71 is formed by repeatedly connecting the upper electrode 1f of the battery cell 1 by soldering the ribbon wire 2 to obtain a desired voltage.
Then, as shown in FIG. 14, the string 71 is sandwiched between a transparent protective layer 60 made of tempered glass or the like and a back sheet 61 via a filler 62 such as EVA (ethylene vinyl acetate) resin. Then, the filler 62 is melted by heating and then laminated by pressurizing and bonding. Thereafter, a frame made of aluminum or the like is provided on the four sides for protecting the back surface. In this way, a conventional solar cell module is produced.

JP-A-6-151932 JP-A-61-69179 JP-A-11-204811

When the plurality of solar cell elements 1 are connected to form the string 71 as described above, the solar cell elements are connected by the ribbon line 2, and the ribbon line 2 has a thickness Ha of about 200 μm (FIG. 13). ) And the connecting portion with the ribbon wire 2 becomes unevenly thick, so that stress is easily concentrated on the connecting portion with the ribbon wire 2 of the solar cell element. Since pressure is applied to bond the solar cell element 1 to the transparent protective layer 60 or the like even during laminating or the like, the solar cell element 1 may be bent and cracked.
Then, an object of this invention is to provide the technique which suppresses the stress concentration to a solar cell element and prevents the crack of a solar cell element.

In order to solve the above-described problems, the solar cell module and the manufacturing method thereof according to the present invention are configured as follows. That is, the solar cell module of the present invention is
A flat substrate;
At least one conductive land formed on the substrate;
A planar solar cell element in which a first electrode is provided on one surface and a second electrode is provided on the other surface;
A connection portion that is partially interposed between the second electrode and the conductive land portion of the solar cell element and connects the second electrode and the conductive land portion in a facing state;
A gap between the second electrode of the solar cell element and the conductive land portion generated by the interposition of the connection portion is 100 μm or less.

A plurality of solar cell elements connected to the conductive land portion by the connection portion are provided on the substrate, and the conductive land portion connected to the second electrode of one solar cell element is another solar cell element. The first electrode or the second electrode may be electrically connected.

  The conductive land portion connected to the second electrode of one solar cell element may be electrically connected to the first electrode of another solar cell element via a wiring material.

  A solar cell element having the second electrode as a positive electrode and a solar cell element having the second electrode as a negative electrode may be connected via the conductive land.

The solar cell module further comprises a protective layer,
The protective layer may be disposed on the light receiving surface side of the solar cell element, and may be adhered by pressurization.

Moreover, the manufacturing method of the solar cell module of the present invention includes:
Forming at least one conductive land on a flat substrate;
The solar cell element is disposed with the second electrode of the flat plate solar cell element provided with the first electrode on one surface and the second electrode provided on the other surface facing the conductive land portion of the substrate. ,
When connecting the non-light-receiving surface side electrode and the conductive land portion by partially interposing a connection portion between the second electrode of the solar cell element and the conductive land portion on the substrate, The gap between the second electrode of the solar cell element and the conductive land portion generated by the interposition is set to 100 μm or less.

In the method for manufacturing the solar cell module, a plurality of solar cell elements connected to the conductive land portion by the connection portion are provided on the substrate, and the conductive property is connected to the second electrode of one solar cell element. The land portion may be electrically connected to the first electrode or the second electrode of another solar cell element.

  In the manufacturing method of the solar cell module, the conductive land portion connected to the second electrode of one solar cell element may be electrically connected to the first electrode of another solar cell element via a wiring material. good.

  In the method for manufacturing the solar cell module, a solar cell element having the second electrode as a positive electrode and a solar cell element having the second electrode as a negative electrode may be connected via the conductive land.

  In the method for manufacturing the solar cell module, a protective layer may be disposed on the light receiving surface side of the solar cell element and may be adhered by pressurization.

ADVANTAGE OF THE INVENTION According to this invention, the technique which suppresses the stress concentration to a solar cell element and prevents the crack of a solar cell element can be provided.
Therefore, a tempered glass protective layer, a metal frame, or the like that has been conventionally provided for preventing cracking is not required, and the thickness and weight of the solar cell module can be reduced. As a result, the crystalline silicon solar cell module having high photoelectric conversion efficiency can be reduced in weight and thickness, and can be easily transported and handled. In addition, when installing on an upper part of a building structure or a car, etc., there are great effects such as easy installation of a large area and no need to reinforce the roof or the fuselage.

Schematic cross section of solar cell module Illustration of conductive land Explanatory drawing of connection part 4 Explanatory drawing of the separation distance between the solar cell element and the substrate Explanatory drawing of pressure applied to solar cell element Explanatory drawing of pressure applied to solar cell element Explanatory drawing of pressure applied to solar cell element Explanatory drawing of pressure applied to solar cell element Explanatory drawing of manufacturing method of solar cell module Plan view showing conductive land provided on substrate The figure which shows the example which connected the solar cell element in series Schematic diagram of laminating equipment with solar cell elements set Cross section of solar cell module Illustration of junction box Sectional drawing of the solar cell module of the modification 1 The figure which shows the example of a connection of the conventional solar cell element Schematic diagram of a conventional solar cell module

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view of the solar cell module 10, and FIG. 2 is a schematic perspective view specifically showing an electrode portion of the solar cell element 1 shown in FIG. The solar cell module 10 of the present embodiment includes a conductive land portion 5a formed on a flat glass epoxy substrate 5 (hereinafter referred to as substrate 5) and a lower electrode (second electrode and back electrode) of the solar cell element 1. 1b is connected by the connection part 4, and the solar cell element 1 is laminated by the sealing material 7 and the protective layer 9 as described later.

  The solar cell element 1 is provided on the semiconductor layer 1s that converts light energy into electric power by the photovoltaic effect, and on the light receiving surface (the surface opposite to the plane facing the substrate 5 in FIG. 1) of the semiconductor layer 1s. And an upper electrode (also referred to as a first electrode or a surface electrode) 1 f and a lower electrode 1 b provided on the non-light-receiving surface (a plane facing the substrate 5 in FIG. 1) of the semiconductor layer 1 s.

The semiconductor layer 1s is formed by, for example, diffusing phosphorus on a p-type silicon wafer (substrate) cut out from a single crystal silicon ingot to form a pn junction. The semiconductor layer 1s is not limited to this, but is made of polycrystalline silicon, a pn junction formed on an n-type silicon wafer, a non-doped amorphous silicon layer and a p-type amorphous silicon on an n-type silicon wafer. The thing using the crystalline silicon wafers, such as a hybrid type solar cell which laminated | stacked the layer in order, may be used.
As the semiconductor layer 1s, amorphous silicon, inorganic semiconductor materials such as CIGS and CIS, dyes, and organic semiconductor materials may be used. However, the present invention relates to a solar cell using a brittle material such as crystalline silicon. The application effect is high.

  A transparent electrode 1fc that is a current collector that extracts electric power generated in the semiconductor layer 1s but does not block incident light is provided on the entire light-receiving surface side of the semiconductor layer 1s (FIG. 2). Examples of the transparent electrode include ITO (indium tin oxide), IZO (indium zinc oxide), ATO (antimony-doped tin oxide), ZTO (zinc-doped tin oxide), AZO (aluminum-doped zinc oxide), and GZO (gallium-doped zinc oxide). ), An oxide film such as FTO (fluorine-doped tin oxide), or an oxide-metal composite film in which Ag or Cu is sandwiched between ITO and the like.

  Further, on the transparent electrode 1fc, an Ag electrode 1fa is provided as a highly conductive current collector in order to efficiently extract the electric power generated in the semiconductor layer 1s.

  The Ag electrode 1fa has a plurality of trunk portions aa that traverse the light receiving surface of the solar cell element 1 in the X direction in FIG. 2 and a plurality of branch portions ab extending from the trunk aa in a comb-teeth shape in the Z direction in FIG. And it is formed in a lattice shape. The ribbon wire 2 is connected to the trunk aa of the Ag electrode 1fa. The electric charges generated in the semiconductor layer 1s reach the Ag electrode 1fa via the transparent electrode 1fc, gather from the branch part ab of the Ag electrode 1fa to the trunk part aa, and flow to the ribbon line 2.

The Ag electrode 1fa is formed by applying an Ag paste and baking it. Further, in the region other than the Ag electrode 1fa on the transparent electrode 1fc, an antireflection layer 1fb made of a dielectric material such as silicon nitride or silicon oxide is formed in order to increase the power generation efficiency without reflecting incident light as much as possible. Yes. The antireflection layer 1fb is formed by a film forming method such as CVD. FIG. 3A is a plan view of the light-receiving surface side of the solar cell element 1 provided with the Ag electrode 1fa and the antireflection layer 1fb.
When the electrical resistance of the transparent electrode 1fc is sufficiently low, the Ag electrode 1fa is only the trunk aa and the branch ab is not necessarily provided. This is preferable because the light receiving area of the solar cell element 1 is increased.

  A lower electrode 1b is provided on the non-light-receiving surface side of the semiconductor layer 1s. The lower electrode 1b is not necessarily provided on the entire surface of the semiconductor layer 1s on the non-light-receiving surface side, but is preferably provided on the entire surface in order to obtain a light confinement effect for preventing light transmission. The lower electrode 1b is formed by applying Ag paste or Al paste and baking it.

  Since Ag has higher conductivity than Al, it is preferable to use the lower electrode 1b as the entire surface Ag in order to efficiently extract the electric power generated in the semiconductor layer 1s. Etc. are preferable. For example, on the substrate 5, it is preferable that the region facing the connection portion 4 is an Ag electrode 1ba and the other region is an Al electrode 1bb.

FIG. 3B is a plan view of the non-light-receiving surface side of the solar cell element 1 provided with the Ag electrode 1ba and the Al electrode 1bb. In the present embodiment, as shown in FIG. 3B, the Ag electrode 1ba is formed in three parallel lines extending in the Z direction, and each Ag electrode 1ba is connected to the connection portion 4 (FIG. 2).
).

  The protective layer 9 is formed for the purpose of mechanical strength, weather resistance, scratch resistance, chemical resistance, gas barrier properties, and the like. From the viewpoint of not impeding the light absorption of the solar cell element 1, one that transmits visible light is preferable. Further, since the solar cell module 10 is often heated by receiving light, the protective layer 9 preferably has heat resistance, and the melting point of the constituent material of the protective layer 9 is usually 100 ° C. to 350 ° C.

  The material of the protective layer 9 can be selected in consideration of these characteristics and is not particularly limited. For example, polyethylene resin, polypropylene resin, cyclic polyolefin resin, AS (acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene). ) Resin, polyvinyl chloride resin, fluorine resin, polyester resin such as polyethylene terephthalate, polyethylene naphthalate, phenol resin, polyacrylic resin, (hydrogenated) epoxy resin, polyamide resin such as various nylons, polyimide resin, polyamide -Imide resin, polyurethane resin, cellulosic resin, silicone resin, polycarbonate resin and the like can be mentioned.

  Among them, fluorine resin is preferable, and specific examples thereof include polytetrafluoroethylene (PTFE), 4-fluoroethylene-perchloroalkoxy copolymer (PFA), 4-fluoroethylene-6-fluoride. Propylene copolymer (FEP), 2-ethylene-4-fluoroethylene copolymer (ETFE), poly-3-fluoroethylene chloride (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), etc. Can be mentioned.

  Note that the protective layer 9 may be formed of two or more materials, and the protective layer 9 may be a single layer or a laminate composed of two or more layers.

  The thickness of the protective layer 9 is not particularly limited, but is usually 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and usually 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less. Increasing the thickness tends to increase the mechanical strength, and decreasing the thickness tends to improve the transmittance of visible light.

  The sealing material layer 7 is usually provided for the purpose of sealing the solar cell element 1 and bonding the protective layer 9, but also contributes to improvements in mechanical strength, weather resistance, gas barrier properties, and the like. Further, at least the sealing material layer 7 on the light receiving surface side of the solar cell element 1 preferably transmits visible light and has high heat resistance like the protective layer 9.

  The material of the encapsulant layer 7, that is, the encapsulant can be selected in consideration of these characteristics, and is not particularly limited. For example, ethylene-vinyl acetate copolymer (EVA) resin, polyolefin resin, AS ( Acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, polyvinyl chloride resin, fluorine resin, polyester resin such as polyethylene terephthalate, polyethylene naphthalate, phenol resin, polyacrylic resin, (hydrogenated) epoxy Examples thereof include polyamide resins such as resins and various nylons, polyimide resins, polyamide-imide resins, polyurethane resins, cellulose resins, silicone resins, and polycarbonate resins.

  Among them, an ethylene copolymer resin is preferable, and an ethylene-vinyl acetate copolymer (EVA) resin or a polyolefin resin made of a copolymer of ethylene and another olefin is more preferable. For example, a resin made of propylene / ethylene / α-olefin copolymer, ethylene / α-olefin copolymer, or the like.

  An ethylene-vinyl acetate copolymer (EVA) resin composition is usually made into an EVA resin by blending a crosslinking agent in order to improve weather resistance to form a crosslinked structure. As the crosslinking agent, an organic peroxide that generates radicals at 100 ° C. or higher is generally used. For example, 2,5-dimethylhexane; 2,5-dihydroperoxide; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane; 3-di-t-butylperoxide It is done. The compounding quantity of an organic peroxide is 1-5 weight part normally with respect to 100 weight part of EVA resin. Moreover, you may contain a crosslinking aid, a silane coupling agent for the purpose of an adhesive improvement, hydroquinone etc. for the purpose of improving stability.

  As the propylene / ethylene / α-olefin copolymer, a thermoplastic resin composition in which a propylene polymer and a soft propylene copolymer are blended in an appropriate composition is usually used.

  The sealing material layer 7 may be formed of two or more kinds of materials, and the sealing material layer may be a single layer or a laminate composed of two or more layers.

  The thickness of the sealing material layer 7 is not particularly limited, but is usually 100 μm or more, preferably 150 μm or more, more preferably 200 μm or more, and usually 3 mm or less, preferably 1.5 mm or less, more preferably 1 mm or less. . Increasing the thickness tends to increase the mechanical strength of the solar cell panel, and decreasing the thickness tends to improve the transmittance of visible light.

  In order to prevent deterioration of the solar cell element 1, a UV absorption layer may be provided on the light receiving surface side of the solar cell element 1. For example, a UV absorber may be applied on the sealing material layer 7, or a film containing a UV absorber may be laminated on the sealing material layer 7. Alternatively, a UV absorber may be included in the sealing material 7 or the protective layer 9 itself.

  The substrate 5 is a glass epoxy substrate formed by impregnating an epoxy resin with a glass fiber cloth (cloth) layered thereon and shaping it on a rectangular flat plate, and laminating a copper layer and a nickel layer on at least one surface. The conductive land portion 5a is formed. The substrate 5 may be a so-called printed substrate, and is not limited to a glass epoxy substrate, but may be a paper phenol substrate (baked substrate), a paper epoxy substrate, a glass composite substrate, a Teflon (registered trademark) substrate, an alumina substrate, or the like. Also good.

  The thickness of the board | substrate 5 should just be the thickness which can fully maintain rigidity, for example, is about 0.5-3 mm.

  The substrate 5 is preferably a rigid substrate having high rigidity for protection of the solar cell element 1. However, when the solar cell module 10 is installed, if a sufficient rigidity is obtained by the installation surface or the like, a flexible substrate is used. It may be used.

  A plurality of conductive land portions 5 a are provided on the substrate 5 at intervals in the connection direction of the solar cell elements 1. As shown in FIG. 2, each conductive land portion 5a is usually formed to be the same as or slightly larger than the bottom surface of the solar cell element 1, and at least a part thereof is used as the electrode lead portion 5b. For example, the electrode lead-out part 5b places the solar cell element 1 at a predetermined position on the conductive land part 5a in a portion that does not overlap the solar cell element 1 in the height direction (y direction), and is a plan view from above. Then, the portion of the conductive land portion 5a that protrudes from the solar cell element 1 is used as the electrode lead portion 5b. Alternatively, as shown in FIG. 4, an extension having a width that is the same as or wider than the width of the ribbon line 2 that extends from one side of a rectangle arranged in a direction orthogonal to the connection direction of the solar cell elements 1. It is also possible to form a conductive land portion 5a provided with a portion as an electrode lead portion 5b. However, the number of extending portions and the extending direction thereof are not limited to the example of FIG.

  The area of the conductive land portion 5a can be appropriately determined as long as there is no significant adverse effect on the implementation of the present invention, but at least corresponds to a size capable of extracting a desired current from the lower electrode 1b, for example, the Ag electrode 1ba of the lower electrode 1b. The size to be. Therefore, the area of the conductive land portion 5a is not less than the size corresponding to the Ag electrode 1ba and is the same as or slightly larger than the bottom surface of the solar cell element 1. The area of the conductive land 5a is preferably larger within this range. Note that the conductive land portion 5a may be formed by maximizing the area of the conductive land portion 5a by deleting only unnecessary portions for ensuring insulation from the adjacent conductive land portion 5a. When the conductive land portion 5a is made large, the rigidity can be increased, and when the conductive land portion 5a is provided by the subtractive method, the production time can be shortened and the cost can be reduced.

  Further, the conductive land portions 5 a may be provided on both surfaces of the substrate 5. By providing the conductive land portions 5a on both surfaces of the substrate 5 in this way, the rigidity can be further increased, the state of both surfaces of the substrate can be made the same, and warpage can be prevented. Further, when the solar cell elements 1 on the substrate 5 are electrically connected to each other, they may be connected by using the through holes and the conductive land portions 5a on the back surface.

  On this conductive land portion 5a, Ag paste as a connection portion 4 is screen-printed in a predetermined pattern, and the solar cell element 1 is placed on this pattern with the lower electrode 1b facing downward (substrate 5 side). Then, the conductive land portion 5a of the substrate 5 and the lower electrode 1b of the solar cell element 1 are connected by heating in a reflow furnace. The connection part 4 of this embodiment is formed in the same pattern as the Ag electrode 1ba shown in FIG.

  Here, the thickness of the connecting portion 4, that is, the separation distance H1 between the solar cell element 1 and the conductive land portion 5a due to the interposition of the connecting portion 4 is set to 100 μm or less. By setting the separation distance H1 to 100 μm or less, the possibility that the solar cell element 1 breaks when stress concentrates on the connection portion 4 is reduced. In addition, if the separation distance H1 is reduced, when the pressure from above is applied to the solar cell module 10 and the solar cell element 1 bends with the connection portion 4 as a fulcrum, it is limited by the conductive land portion 5a located below the solar cell element 1. Therefore, the upper limit value of the separation distance H1 is set to 70 μm or less so that cracking of the solar cell element 1 does not occur due to an expected pressure such as pressurization at the time of laminating. Further, it is desirable that the thickness is 50 μm or less.

  On the other hand, in order to perform screen printing or application of the connecting portion 4 with a uniform thickness, it is preferable that there is a certain thickness. For example, the separation distance H1 is preferably 5 μm or more. Since the optimal film thickness of the conductive adhesive such as Ag paste is determined depending on the type of conductive filler and binder, the Ag paste and Ni paste have good connectivity with the Ag electrode 1ba and the Ni conductive land portion 5a. When the material is selected, the lower limit value of the separation distance (thickness of the connecting portion 4) H1 is preferably 10 μm or more, more preferably 20 μm or more.

  The connection part 4 should just have the electroconductivity which can transmit the electric current from the solar cell element 1 to the electroconductive land part 5a without trouble, and material is not limited. For example, it can be formed by baking a conductive adhesive such as Ag paste or an elastic body such as a conductive tape. As an electroconductive tape, what formed the electroconductive adhesive layer on both surfaces of metal foil, such as copper and aluminum, for example can be used.

  In addition, when the connection part 4 consists of an elastic body which has elasticity or flexibility, the thickness at the time of pressurization is set to H1. The degree of pressurization is, for example, the pressure applied when laminating with a vacuum laminator or the pressure applied when transporting the solar cell module 10, the pressure assumed when the solar cell module 10 is installed, It determines based on the pressure assumed at the time of use of the solar cell module 10, such as surface cleaning. When the connection part 4 consists of an elastic body, since the stress by bending can be partially absorbed, it is preferable.

  Further, the interval D1 between the connecting portions 4 may be set arbitrarily, but the degree of bending when pressure is applied to the solar cell element 1 is also affected by the interval D1, so the interval D1 is set to a predetermined range. Also good. There are two desirable ranges of the distance D1, a case where the distance D1 is wide and a case where the distance D1 is narrow. First, the lower limit value when the distance D1 is wide is preferably 40 mm or more, more preferably 50 mm or more, and the upper limit value when the distance D1 is wide is preferably 100 mm or less, and more preferably 90 mm or less. If it is equal to or greater than the lower limit value, the bending method is gentle and difficult to break, and if it is equal to or less than the upper limit value, a current efficiently flows from the lower electrode 1b to the land portion 5a to improve power generation efficiency.

  Alternatively, the lower limit value when the distance D1 is narrowed is preferably 3 mm or more, more preferably 5 mm or more, and the upper limit value when the distance D1 is narrowed is desirably 20 mm or less, and more desirably 10 mm or less. If it is above the lower limit value, it can be used effectively while suppressing the amount of materials used such as Ag paste and conductive tape, and if it is below the upper limit value, it is difficult to bend and crack.

The influence of bending becomes large when the distance D1 is wide and the range when narrow (hereinafter referred to as the intermediate range), that is, when the distance D1 is larger than 20 mm and smaller than 40 mm.

  5A to 5D are diagrams showing the relationship between the distance D1 and the degree of deflection when pressure is applied to the solar cell element 1. FIG. In addition, although the solar cell element 1 using the crystalline silicon wafer of this embodiment is not a flexible member, FIG. 5B-FIG.

  FIG. 5A shows a state where no pressure is applied, and FIG. 5B shows a case where the pressure from the light receiving surface side to the substrate side is applied to the solar cell element 1 when the distance D1 is set to the intermediate range, and the solar cell element 1 faces the substrate 5. The state which has bent in the convex is shown. FIG. 5C shows a state in which pressure is applied in the same manner as FIG. 5B when the distance D1 is widened to be the desired range (40 mm to 100 mm), and FIG. In this case, the pressure is applied as in FIG. 5B.

  In the example shown in FIGS. 5B and 5C, when pressure is applied and the solar cell element 1 is bent, the radius of curvature of bending is greater in the wider space D1 (FIG. 5C) than in the narrower space D1 (FIG. 5B). Since it becomes large, the influence of bending is small.

  On the other hand, when the distance D1 is narrower than that shown in FIG. 5B (20 mm or less) as shown in FIG. 5D, the solar cell element 1 is held tightly at the connecting portion 4 and the amount of bending is reduced. Few.

  For this reason, when the connection part H1 is 100 μm or less as in the present embodiment, it is desirable that the distance D1 be 3 mm or more and 20 mm or less, or 40 mm or more and 100 mm or less.

Further, the contact area of the connecting portion 4 with the lower electrode 1b of the solar cell element 1 is not particularly limited, but is preferably 2% or more of the lower electrode 1b. More desirably, it is 4% or more. When the contact area of the connection portion 4 is increased, the solar cell element 1 can be closely supported by the connection portion 4 as in the case where the distance D1 is reduced, and the influence of bending can be reduced. Moreover, there exists an advantage which the electric current from the solar cell element 1 tends to flow into the electroconductive land part 5a. On the other hand, since it is redundant if the contact area is too large, the contact area is desirably 50% or less. More desirably, it is 20% or less.
The contact portion is preferably provided so as to correspond to at least a region formed of Ag in the lower electrode 1b.

  When the solar cell elements 1 are connected in series, the electrode lead portion 5b of the conductive land portion 5a and the upper electrode 1f of the solar cell element 1 are connected by the ribbon wire 2. FIG. 4 is a schematic perspective view showing a state in which the electrode lead portion 5b and the upper electrode 1f are connected by the ribbon wire 2. FIG.

  As described above, since the ribbon wire 2 and the electrode lead portion 5b are connected at a position that does not overlap the solar cell element 1, the solder 6 (FIG. 1) used to connect the ribbon wire 2 and the electrode lead portion 5b is thick. Even if it becomes, since it can avoid that the ribbon wire 2 and the solar cell element 1 contact or adjoin, the deformation | transformation of the solar cell module 10 can reduce the influence of the stress generation to the solar cell element 1 by the ribbon wire 2. The cracking of the solar cell element 1 caused by the ribbon wire 2 can be prevented.

Next, the manufacturing method of the solar cell module 10 is demonstrated. FIG. 6 shows a manufacturing procedure of the solar cell module 10 of the present embodiment.
First, conductive land portions 5a having a predetermined pattern are formed on the substrate 5 (step S1). For example, an unnecessary portion of the Cu conductive layer formed on the entire surface of the insulating substrate is removed by a subtractive method, and a conductive layer having a predetermined pattern as shown in FIG. 7 is left as the conductive land portion 5a. Alternatively, the conductive land portion 5a may be formed by depositing a conductive layer on the insulating substrate by the additive portion method. FIG. 7 shows an example in which a plurality of conductive land portions 5a having extending portions used as one electrode lead portion 5b in the direction in which current flows are formed on the substrate 5.

  Further, it is preferable to provide a layer of Ni, Au, Rh, etc. on the Cu layer formed in this way. It is particularly preferable to provide a Ni layer on the Cu layer. 1 and 2 show an example in which the conductive land portion 5a is formed of a Cu layer and a Ni layer. Since Ni has high rigidity, the rigidity of the solar cell module 10 can be increased and the cost is low. As a manufacturing method, it is preferable that a Cu layer is provided by a subtractive method, and then the Ni layer is deposited by plating using the Cu layer as an electrode.

  The thickness of the conductive land portion 5a is, for example, 30 μm or more in order to increase rigidity. Moreover, in order to suppress the usage-amount of material, it is good also considering the thickness of the electroconductive land part 5a as 200 micrometers or less normally.

  Next, the paste 4 is screen-printed to print the connection portion 4 on the conductive land portion 5a of the substrate 5 (step S2), and the solar cell element 1 is placed on the connection portion 4 (step S2). S3), heated in a reflow furnace (step S4), the connecting portion 4 is cured, and the lower electrode 1b and the upper electrode 1f of the solar cell element 1 are connected.

  Further, a solder paste is applied on the electrode lead portions 5b of each conductive land portion 5a and the upper electrode 1f of the solar cell element 1, and the ribbon wire 2 is disposed from the adjacent electrode lead portion 5b to the upper electrode 1f and heated. The adjacent solar cell elements 1 are electrically connected by soldering (step S5). FIG. 8 shows an example in which the solar cell elements 1 are connected in series in a meander shape from the electrode 31 to the electrode 32 (example in which a string is formed).

  Then, the substrate 5 on which the solar cell element 1 is mounted and the sealing material (EVA) 7 and the transparent protective layer (ETFE) 9 are stacked on the laminating apparatus 20 in this order (step S6). FIG. 9 is a schematic view of a laminating apparatus in which the solar cell element 1 and the like are set. The stacking order of the solar cell elements 1 and the like may be reversed upside down.

The laminating apparatus 20 includes a first chamber 41 and a second chamber 42, and the first chamber 41 and the second chamber 42 are separated by a diaphragm 43,
The valves V1 and V2 are connected to a vacuum pump (not shown). The solar cell element 1 or the like as the laminate 44 is placed in the second chamber 42.

  Then, the first chamber 41 and the second chamber 42 are evacuated to a vacuum state (step S7), and the sealing material 7 is in a molten state and does not cause a crosslinking reaction by the heater 45 of the second chamber 42. Heat to the temperature region (step S8).

  Next, the inside of the first chamber 41 is returned to atmospheric pressure while the second chamber 42 is kept in vacuum. Then, the diaphragm 43 is pushed to the inside of the second chamber due to the pressure difference between the first chamber 41 and the second chamber 42, and the object to be laminated is pressurized and pressed (step S9).

  Next, the object to be laminated 44 is heated to a temperature range where EVA causes a crosslinking reaction, and this temperature is maintained for a predetermined time until the crosslinking reaction is completed (step S10). After the predetermined time elapses, cooling is performed (step S11), and the laminated body, that is, the solar cell module 10 is taken out. (Step S12).

  FIG. 10 is a cross-sectional view taken along line AA after laminating the string of solar cell elements 1 shown in FIG. As shown in FIG. 10, in the solar cell module 10 of the present embodiment, the lower electrode 1b of the solar cell element 1 is connected to the conductive land portion 5a on the substrate 5, and the electrode lead-out portion 5b of the conductive land portion 5a It is the structure which connects the upper electrode 1f of the adjacent solar cell element 1 with the ribbon line 2, the ribbon line 2 is not arrange | positioned under the solar cell element 1, but the solar cell element 1 is flat on the board | substrate 5 with high rigidity. Held along.

  Thus, if it is the manufacturing method of this embodiment, the stress which the connection part 4 exerts on the solar cell element 1 can be reduced, and the crack of the solar cell element 1 can be prevented.

  Moreover, since the solar cell module 10 of this embodiment has the board | substrate 5 with high rigidity and is not easily influenced by bending, it is not necessary to use a glass protective layer or an aluminum frame. , Can be reduced in weight and thickness. For this reason, the solar cell module 10 of this embodiment can be suitably installed in the upper part of moving bodies, such as a roof of a building structure, a wall surface, a motor vehicle, and a ship.

  According to the present embodiment, since the solar cell element 1 is not easily broken even during pressurization, it is possible to perform lamination using a general pressure roller or the like in addition to the vacuum laminator described above. However, it is preferable to use a vacuum laminator because it can be laminated even if the surface of the solar cell module is uneven.

  An epoxy resin may be used as the sealing material 7 instead of EVA. In this case, a weir is provided around the substrate 5, a liquid epoxy resin is poured onto the cell, and after placing an ETFE sheet as the protective layer 9, the epoxy resin is cured by leaving or heating. If it is the method using the said epoxy resin, a pressurization lamination is unnecessary. Epoxy resins include a one-pack type with good workability and a two-pack type with excellent transportability and storage stability, and can be selected as necessary.

  In the present embodiment, power is drawn to the back side of the substrate 5. FIG. 11A is a cross-sectional view of a location where the junction box 50 is provided, and FIG. 11B is a plan view of the back surface side of the solar cell module 10 provided with the junction box 50.

As shown in FIG. 11A, the electrodes 31 and 32 on the front surface side and the electrodes 31B and 32B on the back surface side are electrically connected through the through holes 31A and 32A, and the electrodes 31B and 32B on the back surface side and the junction box 50 The terminals 51 and 52 are electrically connected with solder or the like. Thereafter, the periphery of the connection portion is sealed with a sealing material such as silicone resin. As a result, the power generated by the string of solar cell elements 1 is output to the outside through the cables 51A and 52A electrically connected to the terminals 51 and 52 of the junction box 50 as shown in FIG. .

  By providing the junction box 50 on the back surface side of the solar cell module 10 in this way, the junction box 50 and the cables 51A and 52A are not easily affected by the external environment, and high light resistance and weather resistance are obtained.

  The junction box 50 is not limited to the back side of the solar cell module 10 and may be provided on the front side.

  For example, the EVA sheet as the sealing material 7 and the ETFE sheet as the protective layer 9 are laminated on the entire surface, and then the EVA sheet and the ETFE sheet at the junction box connection portion are removed before lamination (for example, cut out into squares). After lamination, remove any EVA protrusions. Then, the exposed electrodes 31 and 32 and the terminals of the junction box (the illustration is omitted because it has the same configuration as FIG. 11A) are connected by solder or the like, and the periphery of the connection portion in the junction box is a silicone resin. Seal with a sealing material such as

  Thus, since the solar cell module 10 provided with the junction box on the front surface side does not need to be provided with a protrusion on the back surface, it is suitable when the solar cell module 10 is installed on a roof or the like. In this case, the junction box may be protected with a cover or the like in order to improve light resistance and weather resistance.

  In addition, although how many solar cell elements 1 may be formed on the board | substrate 5, it is about 1-4 normally.

<Modification 1>
FIG. 12 is a schematic diagram of the first modification. In the example of FIG. 10, the solar cell element 1 (which is also referred to as a p-type solar cell element 1p for convenience) in which a pn junction is formed on a p-type silicon wafer is used as the semiconductor layer 1s. However, in this example, the conductor layer 1s is used. As shown, solar cell elements 1 (which are also referred to as n-type solar cell elements 1n for convenience) and p-type solar cell elements 1p each having a pn junction formed on an n-type silicon wafer are alternately arranged.

  In the n-type solar cell element 1n, the lower electrode 1b is a negative electrode and the upper electrode 1f is a positive electrode, which is opposite to the p-type solar cell element 1, so when these are connected in series, as shown in FIG. Adjacent n-type solar cell element 1 and p-type solar cell element 1 are connected via the same conductive land portion 5a, and upper electrode 1f of p-type solar cell element 1 is placed on a different conductive land portion 5a. The upper electrode 1 f of the n-type solar cell element 1 thus connected is connected by a ribbon wire 2.

As described above, in the example shown in FIG. 12, a part connected by the ribbon wire 2 can be partially omitted as compared with the example shown in FIG. 10, and the manufacturing process can be simplified. Thereby, the solar cell module 10 can be manufactured at low cost. Moreover, it is not necessary to provide the electrode lead-out part 5b between the adjacent solar cell elements 1, and the mounting density of the solar cell elements 1 can be increased.
On the other hand, since only one type of solar cell element is used in the example of FIG.

DESCRIPTION OF SYMBOLS 10 Solar cell module 1 Solar cell element 2 Ribbon wire 4 Connection part 5 Substrate 5a Conductive land part 5a
7 Sealing material 9 Protective layer

Claims (7)

A flat substrate;
At least one conductive land formed on the substrate;
A planar solar cell element in which a first electrode is provided on one surface and a second electrode is provided on the other surface;
A connection portion that is partially interposed between the second electrode and the conductive land portion of the solar cell element and connects the second electrode and the conductive land portion in a facing state;
The solar cell module, wherein a gap between the second electrode of the solar cell element and the conductive land portion generated by the interposition of the connection portion is 100 μm or less. A plurality of solar cell elements connected to the conductive land portion by the connection portion are provided on the substrate, and the conductive land portion connected to the second electrode of one solar cell element is another solar cell element. The solar cell module according to claim 1, wherein the solar cell module is electrically connected to the first electrode or the second electrode.   The solar cell module according to claim 2, wherein the conductive land portion connected to the second electrode of one solar cell element is electrically connected to the first electrode of another solar cell element via a wiring member. .   The solar cell module according to claim 2, wherein a solar cell element having a second electrode as a positive electrode and a solar cell element having a second electrode as a negative electrode are connected via the conductive land. The solar cell module further comprises a protective layer,
The solar cell module according to any one of claims 1 to 4, wherein the protective layer is disposed on a light receiving surface side of the solar cell element and is adhered by pressurization. Forming at least one conductive land on a flat substrate;
The solar cell element is disposed with the second electrode of the flat plate solar cell element provided with the first electrode on one surface and the second electrode provided on the other surface facing the conductive land portion of the substrate. ,
When connecting the non-light-receiving surface side electrode and the conductive land portion by partially interposing a connection portion between the second electrode of the solar cell element and the conductive land portion on the substrate, A method for manufacturing a solar cell module, wherein a gap between the second electrode of the solar cell element and the conductive land portion generated by the interposition is set to 100 μm or less.   The manufacturing method of the solar cell module of Claim 6 which arrange | positions a protective layer to the light-receiving surface side of the said solar cell element, and makes it closely_contact | adhere by pressing.

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