WO2013140552A1 - Solar cell module - Google Patents

Abstract

Disclosed is a solar cell module that is provided with a plurality of solar cells, each of which comprises a photoelectric conversion unit, and a tab which electrically connects the plurality of solar cells. In the peripheral portion of each solar cell, a buffering material, which has a lower hardness than the photoelectric conversion unit, is arranged between the photoelectric conversion unit and the tab.

Description

Solar cell module

The present invention relates to a solar cell module.

Examples of solar cells include single crystal solar cells, polycrystalline solar cells, amorphous solar cells, and the like, or combinations thereof. Usually, a plurality of solar cells are connected in series or in parallel and used as a solar cell module.

12 shows a configuration of a conventional solar cell module 100. FIG. The solar cell module 100 has a structure in which a plurality of solar cells 10 are connected by tabs 12. The tab 12 connects the first electrode 14 of the solar battery cell 10 and the second electrode 16 of the adjacent solar battery cell 10. Here, the tab 12 has a bent portion 12 a provided with a step corresponding to the thickness of the solar battery cell 10.

By the way, when using the solar cell module 100, as shown in the enlarged sectional view of FIG. 13, the peripheral edge portion of the solar cell 10 and the tab 12 are brought into contact with each other and pressed (in the direction of the arrow in the figure), and the solar cell. The cell 10 may be broken. For example, when a thermal cycle is applied to the solar cell module 100, the space between the solar cells 10 is narrowed, the contact between the peripheral portion of the solar cell 10 and the tab 12 occurs, and the solar cell 10 may be damaged. is there.

One aspect of the present invention includes a plurality of solar cells including a photoelectric conversion unit, and a tab for electrically connecting the plurality of solar cells, and the photoelectric conversion unit and the tab are provided at the periphery of the solar cell. Is a solar cell module in which a buffer material having a lower hardness than the photoelectric conversion portion is provided.

According to the present invention, it is possible to suppress the occurrence of cracking of the solar battery cell and improve the reliability of the solar battery module.

It is a top view which shows the structure of the solar cell module in embodiment of this invention. It is sectional drawing which shows the structure of the solar cell module in embodiment of this invention. It is sectional drawing which shows the structure of another example of the solar cell module in embodiment of this invention. It is sectional drawing which shows the structure of another example of the solar cell module in embodiment of this invention. It is sectional drawing which shows the structure of another example of the solar cell module in embodiment of this invention. It is sectional drawing which shows the structure of another example of the solar cell module in embodiment of this invention. It is sectional drawing which shows the structure of another example of the solar cell module in embodiment of this invention. It is a figure which shows the manufacturing method of the solar cell module in embodiment of this invention. It is a figure which shows another example of the manufacturing method of the solar cell module in embodiment of this invention. It is a figure which shows another example of the manufacturing method of the solar cell module in embodiment of this invention. It is sectional drawing which shows the structure of another example of the solar cell module in embodiment of this invention. It is sectional drawing which shows the structure of the conventional solar cell module. It is a figure explaining the subject of the conventional solar cell.

<Configuration of solar cell module>
As shown in the plan view of FIG. 1 and the cross-sectional view of FIG. 2, the solar cell module 200 in the embodiment of the present invention includes a solar cell 20, a tab 22, a buffer material 24, a first protection member 26, and a second protection. The member 28 and the filler 30 are included. FIG. 1 is a plan view of the solar cell module 200 viewed from the light receiving surface side, and FIG. 2 is a schematic cross-sectional view taken along line AA in FIG.

In the following description, the “light receiving surface” is one of the main surfaces of the solar battery cell 20 and means a surface on which light from the outside is mainly incident. For example, 50% to 100% of the light incident on the solar battery cell 20 enters from the light receiving surface side. The “back surface” is one of the main surfaces of the solar battery cell 20 and means a surface opposite to the light receiving surface.

The solar battery cell 20 receives light such as sunlight to generate carriers (electrons and holes), a first electrode 20b provided on the light receiving surface of the photoelectric conversion unit 20a, And a second electrode 20c provided on the back surface of the photoelectric conversion unit 20a. As shown in FIG. 1, the first electrode 20 b and the second electrode 20 c include fingers provided in a comb shape so as to intersect the extending direction of the tab 22 and bus bars connecting the fingers. The bus bars are electrodes that connect the fingers, and are arranged in parallel to each other at a predetermined interval so as to cover the tabs 22. The fingers and bus bars are formed, for example, by screen-printing a conductive paste in which a conductive filler such as silver (Ag) is dispersed in a binder resin in a desired pattern on a transparent conductive layer. When no light is incident from the back surface side of the solar battery cell 20, a metal film such as a silver (Ag) thin film may be formed on substantially the entire back surface of the photoelectric conversion unit 20a to form the second electrode 20c. In the solar battery cell 20, carriers generated by the photoelectric conversion unit 20 a are collected by the first electrode 20 b and the second electrode 20 c.

The photoelectric conversion unit 20a includes a substrate made of a semiconductor material such as crystalline silicon, gallium arsenide (GaAs), or indium phosphorus (InP). The structure of the photoelectric conversion unit 20a is not particularly limited, but in the present embodiment, it will be described as a structure having a heterojunction of an n-type single crystal silicon substrate and amorphous silicon. The photoelectric conversion unit 20a includes, for example, an i-type amorphous silicon layer, a p-type amorphous silicon layer doped with boron (B) or the like on a light-receiving surface of an n-type single crystal silicon substrate, indium oxide or the like. The transparent conductive layers made of a photoconductive oxide are stacked in this order. On the back surface of the substrate, an i-type amorphous silicon layer, an n-type amorphous silicon layer doped with phosphorus (P) or the like, and a transparent conductive layer are laminated in this order.

In the solar battery module 200, the adjacent solar battery cells 20 are connected by a tab 22. As the tab 22, for example, a metal foil such as copper can be used. The tab 22 connects the first electrode 20b of the solar battery cell 20 and the second electrode 20c of the adjacent solar battery cell 20. The tab 22 is bonded to, for example, the bus bar of the first electrode 20b of one solar battery cell 20 and the bus bar of the second electrode 20c of the other solar battery cell 20 by an adhesive layer. As the adhesive layer, for example, a conductive adhesive film in which conductive particles are dispersed in a thermosetting adhesive layer containing an adhesive resin material such as an epoxy resin, an acrylic resin, or a urethane resin can be used. The conductive adhesive film may use an anisotropic conductive adhesive layer having high conductivity in the in-plane direction of the solar battery cell 20 and low conductivity in the film thickness direction. Alternatively, a paste containing no conductive particles may be used for a thermosetting adhesive layer made of an adhesive resin material such as an epoxy resin, an acrylic resin, or a urethane resin.

The tab 22 has a bent portion 22 a provided with a step corresponding to the thickness of the solar battery cell 20. The bent portion 22a has a structural escape corresponding to the thickness of the solar battery cell 20 in order to connect the first electrode 20b and the second electrode 20c so that the adjacent solar battery cells 20 are arranged in the same plane. It is provided to be formed.

The first protective member 26 is a member provided to protect the light receiving surface side of the solar battery cell 20. Since the 1st protection member 26 is provided in the light-receiving surface side of the photovoltaic cell 20, it is comprised from the transparent member which permeate | transmits the light of the wavelength band utilized for photoelectric conversion in the photovoltaic cell 20. FIG. As the 1st protection member 26, the member which has translucency, such as a glass plate, a resin plate, a resin film, can be used, for example. The second protection member 28 is a member provided to protect the back side of the solar battery cell 20. As the second protective member 28, a glass plate, a resin plate, a resin film, or the like can be used as in the first protective member 26. When no light is incident from the back side of the solar battery cell 20, the second protective member 28 may be an opaque plate or film. In this case, as the second protective member 28, for example, a laminated film such as a resin film having an aluminum foil or the like inside may be used. The first protective member 26 and the second protective member 28 are bonded to the first electrode 20 b and the second electrode 20 c of the solar battery cell 20 using the filler 30, respectively.

In the solar cell module 200 according to the present embodiment, as shown in FIG. 2, a buffer material 24 is provided between the tab 20 and the peripheral edge of the solar cell 20. It is preferable that the buffer material 24 is provided between the photoelectric conversion unit 20 a and the tab 22 in a region where the first electrode 20 b and the second electrode 20 c are not provided in the peripheral portion of the solar battery cell 20.

The buffer material 24 is provided in order to buffer the force applied to the solar battery cell 20 when the tab 22 contacts the solar battery cell 20 at the peripheral edge of the solar battery cell 20. Therefore, it is preferable that the buffer material 24 is made of a material having a hardness lower than that of the photoelectric conversion unit 20a of the solar battery cell 20, that is, softer than the photoelectric conversion unit 20a.

The buffer material 24 is preferably a resin material such as an epoxy resin, an acrylic resin, or a urethane resin. For example, an adhesive layer used for adhering the first electrode 20 b or the second electrode 20 c and the tab 22 may be used as the buffer material 24.

The thickness of the buffer material 24 is preferably 5 μm or more and 100 μm or less. By setting it as such a film thickness, the pressure which the photovoltaic cell 20 receives from the tab 22 can be relieve | moderated appropriately.

The buffer material 24 is preferably provided so as not to protrude from the region covered with the tab 22 of the main surface (light receiving surface and back surface) of the solar battery cell 20. By providing the buffer material 24 so as not to protrude from the tab 22, it is possible to prevent the light incident on the photoelectric conversion unit 20 a from being blocked by the buffer material 24, and to suppress a decrease in power generation efficiency in the solar battery cell 20. be able to. When the buffer material 24 is provided so as to protrude from the region covered with the tab 22, it is preferable to use a transparent material that transmits light in a wavelength band used for photoelectric conversion in the solar battery cell 20. Thereby, it can prevent that the light which injects into the photoelectric conversion part 20a by the buffer material 24 is shielded. In addition, when there is no light incident from the back surface, the buffer material 24 on the back surface side may protrude from the region covered with the tab 22.

The cushioning material 24 may be disposed over the entire width direction of the tab 22 (direction perpendicular to the extending direction), or the cushioning material 24 may be disposed only in a part of the tab 22 in the width direction. By providing the buffer material 24 over the entire width of the tab 22, the tab 22 can be prevented from coming into direct contact with the solar battery cell 20 at any location in the width direction of the tab 22. The force applied to 20 can be reliably relaxed. On the other hand, when the buffer material 24 is provided only in a part of the tab 22 in the width direction, the amount of the material used for the buffer material 24 can be reduced.

As shown in FIG. 3, the cushioning material 24 extends from the surface covered by the tab 22 at the peripheral edge of the solar cell 20 to the main surface on the opposite side of the solar cell 20 through the side surface of the solar cell 20. It may be provided so as to cover the part. However, as shown in FIG. 2, the cushioning material 24 is provided from the main surface side covered by the tab 22 at the peripheral edge portion of the solar battery cell 20 to the end side surface, and the sun facing the region where the cushioning material 24 is provided. It is preferable that it is not provided in the region of the main surface on the opposite side of the battery cell 20.

As shown in FIG. 2, by providing the buffer material 24, the amount of the material used for the buffer material 24 can be reduced. An area covered by the tab 22 is an area where the tab 22 and the solar battery cell 20 may be in contact with each other. Therefore, it is possible to substantially avoid the tab 22 from coming into direct contact with the solar battery cell 20 by providing the buffer material 24 at least in the region. As a result, the effect of buffering the force applied to the solar battery cell 20 from the tab 22 is maintained, and damage to the solar battery cell 20 can be prevented.

As shown in FIGS. 2 and 3, the buffer material 24 may be provided from a position away from the first electrode 20b (or the second electrode 20c), or as shown in FIGS. 4 and 5, the first electrode 20b. The buffer material 24 may be provided from a position in contact with (or the second electrode 20c).

By providing the cushioning material 24 from a position away from the first electrode 20b (or the second electrode 20c), the amount of material used for the cushioning material 24 can be reduced. On the other hand, by providing the buffer material 24 from the position in contact with the first electrode 20b (or the second electrode 20c), the sun is surely spread from the position in contact with the first electrode 20b (or the second electrode 20c) to the entire end portion. The battery cell 20 can be protected.

The buffer material 24 may have a shape along the shape of the end portion of the solar battery cell 20 as shown in FIGS. 2 to 5, or may have a fillet shape as shown in FIGS. . Here, the fillet shape indicates a rounded shape. In the present embodiment, the fillet shape has a curvature larger than the curvature of the corner formed by the main surface (light receiving surface or back surface) and the end surface of the solar battery cell 20. It means that it has a shape.

Thus, by making the cushioning material 24 into a fillet shape, the tab 22 comes into contact with the cushioning material 24 in a wider area, and the pressure transmitted from the tab 22 to the solar battery cell 20 via the cushioning material 24 is increased. It can be dispersed more widely. Therefore, the solar battery cell 20 can be more reliably protected.

<Method for forming solar cell module>
Hereinafter, a method for forming the solar cell module 200 will be described. In the solar battery module 200, the solar battery cell 20 can be formed by applying a conventional forming method, and therefore, the forming method of the tab 22 and the buffer material 24 which are characteristic parts will be described.

As shown in FIG. 8A, after the first electrode 20b and the second electrode 20c are formed on the solar battery cell 20, before the tab 22 is formed, the buffer material 24 is formed of a material that becomes the buffer material 24 such as a resin. Apply to the area to be applied. Thereafter, as shown in FIG. 8B, a conductive adhesive film serving as an adhesive layer is disposed on the bus bar of the first electrode 20b and the second electrode 20c, and the tab 22 is bonded to the bus bar. And as shown in FIG.8 (c), it seals with the 1st protection member 26, the 2nd protection member 28, and the filler 30. FIG.

As shown in FIG. 9A, a resin paste 32 as an adhesive layer for adhering the tab 22 is disposed on the first electrode 20b and the second electrode 20c, and as shown in FIG. When press-bonding to the first electrode 20b and the second electrode 20c, the resin paste 32 may protrude from the peripheral portion of the solar battery cell 20 and the portion may be used as the buffer material 24. The resin paste 32 may be an insulating adhesive layer that does not contain a conductive material. In this case, when the tab 22 is pressure-bonded to the first electrode 20b and the second electrode 20c, the resin paste 32 protrudes from the side surfaces of the first electrode 20b and the second electrode 20c. As a result, the tab 22 is in direct contact with and electrically connected to the first electrode 20b and the second electrode 20c. And as shown in FIG.9 (c), it seals with the 1st protection member 26, the 2nd protection member 28, and the filler 30. FIG.

When the conductive adhesive film is used, as shown in FIG. 10, the conductive adhesive film 34 is pasted from the first electrode 20b and the second electrode 20c to the periphery of the solar battery cell 20, and the tab 22 is attached to the first electrode 20b. It is good also as a process crimped | bonded on the 1st electrode 20b and the 2nd electrode 20c. In this case, as shown in FIG. 11, the conductive adhesive film 34 at the peripheral edge of the solar battery cell 20 functions as the buffer material 24. At this time, the conductive adhesive film to be the buffer material 24 in the final structure may be in a state of hanging from the end of the solar battery cell 20.

As described above, according to the solar cell module 200 of the present embodiment, by providing the buffer material 24, the occurrence of cracks and the like of the solar cells 20 is suppressed, and the reliability of the solar cell module 200 is improved. Can do.

10 solar cell, 12 tab, 12a bent portion, 14 first electrode, 16 second electrode, 20 solar cell, 20a photoelectric conversion portion, 20b first electrode, 20c second electrode, 22 tab, 22a bent portion, 24 Buffer material, 26 1st protective member, 28 2nd protective member, 30 filler, 32 resin paste, 34 conductive adhesive film, 100,200 solar cell module.

Claims (4)

A plurality of solar cells including a photoelectric conversion unit;
A tab for electrically connecting the plurality of solar cells;
With
The solar cell module in which the buffer material whose hardness is lower than the said photoelectric conversion part is provided between the said photoelectric conversion part and the said tab in the peripheral part of the said photovoltaic cell. The solar cell module according to claim 1,
The buffer material is provided on one main surface side of the solar battery cell, and the buffer material is provided in a region facing the region provided with the buffer material on the other main surface side of the solar battery cell. Not a solar cell module. The solar cell module according to claim 1 or 2,
The said buffer material is a solar cell module provided continuously from on the electrode formed in the said photovoltaic cell. The solar cell module according to any one of claims 1 to 3,
The buffer material is a solar cell module having a fillet shape.

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