JP7634398B2 - Solar Cell Module - Google Patents

Description

The present invention relates to a solar cell module.

Solar cell modules that have multiple solar cells and perform photoelectric conversion are used. In a solar cell module, only the areas of the solar cells that can receive light contribute to photoelectric conversion. In order to improve the area efficiency (output per area) of a solar cell module, a so-called shingling structure in which the ends of the solar cells are arranged in an overlapping manner may be adopted. When the ends of the solar cells are arranged in an overlapping manner, there is the inconvenience that external forces are concentrated on the overlapping parts of the solar cells, making the solar cells more susceptible to damage.

Patent Document 1 discloses a technology for preventing damage to solar cells caused by stress concentration in the overlapping areas of the solar cells in a solar cell module in which the ends of the solar cells are overlapped and connected to each other using a first current collecting member and a second current collecting member that extend across the space between adjacent solar cells, by disposing insulating material on the ends of the solar cells.

JP 2011-77103 A

The solar cell module described in Patent Document 1 can prevent damage caused by contact between solar cells, but the current collecting members connected to the solar cells at the overlapping portions of the solar cells may be pressed strongly against the solar cells, potentially damaging the solar cells or causing a short circuit. For this reason, the objective of the present invention is to provide a highly reliable solar cell module.

A solar cell module according to one aspect of the present invention comprises a plurality of solar cells, each having a plurality of electrode pads on the back side thereof and arranged so that their ends in a first direction overlap, a plurality of insulating sheets arranged to cover the back sides of the solar cells and having a plurality of connection openings that expose the electrode pads, and a plurality of connection members that connect the electrode pads of adjacent solar cells through the connection openings.

In a solar cell module according to one aspect of the present invention, the distance from an edge of at least one of the electrode pads to the other solar cell may be different from the other electrode pads.

In a solar cell module according to one aspect of the present invention, the solar cell includes a semiconductor substrate, a plurality of first semiconductor layers and a plurality of second semiconductor layers of different conductivity types, each formed in a strip shape extending in a first direction on the rear surface of the semiconductor substrate and arranged alternately in a second direction intersecting the first direction, a plurality of first finger electrodes stacked on the rear surface side of the first semiconductor layers so as to extend in the first direction, a plurality of second finger electrodes stacked on the rear surface side of the second semiconductor layers so as to extend in the first direction, a first bus bar connecting the plurality of first finger electrodes, and a second bus bar connecting the plurality of second finger electrodes, and the electrode pad may be provided on the first bus bar or the second bus bar.

In a solar cell module according to one aspect of the present invention, the insulating sheet may further have a sealing opening in which a sealing material is filled at a position spaced apart from the electrode pad.

The solar cell module according to one aspect of the present invention is highly reliable.

1 is a schematic cross-sectional view of a solar cell module according to one embodiment of the present invention. 2 is a cross-sectional view of a solar cell of the solar cell module of FIG. 1 taken along line XX in a direction perpendicular to FIG. 1. FIG. 2 is a rear view of a solar cell of the solar cell module of FIG. 1 .

Embodiments of the present invention will be described below with reference to the attached drawings. Note that the same or equivalent parts in each drawing will be given the same reference numerals. For simplification, illustrations and reference numerals of components may be omitted, in which case other drawings should be referred to.

Figure 1 is a schematic cross-sectional view of a solar cell module 1 according to one embodiment of the present invention. Figure 2 is an enlarged cross-sectional view of the solar cell module 1 in a direction perpendicular to Figure 1. Figure 3 is an enlarged rear view of the solar cell module 1 in Figure 1.

The solar cell module 1 includes a plurality of solar cells 10 arranged so that their ends in the first direction overlap, a plurality of insulating sheets 20 arranged so as to cover the back surfaces of the solar cells 10, and a plurality of connecting members 30 connecting adjacent solar cells 10 in the first direction. The solar cell module 1 can further include a surface protective member 40 covering the front side of the solar cells 10, the insulating sheets 20, and the connecting members 30, a back protective member 50 covering the back side of the solar cells 10, the insulating sheets 20, and the connecting members 30, and a sealant 60 filled in the space between the surface protective member 40 and the back protective member 50.

In the solar cell module 1, multiple strings are formed by connecting multiple solar cells 10 in a row in a first direction, and are arranged in a second direction intersecting the first direction. Each string is formed by arranging a laminate of solar cells 10 and insulating sheets 20 in a row so that the ends in the first direction overlap, and connecting adjacent solar cells 10 with connecting members 30.

The solar cell 10 has a semiconductor substrate 110, a plurality of first semiconductor layers 121 and a plurality of second semiconductor layers 122 of different conductivity types, each formed in a strip shape extending in a first direction on the back surface of the semiconductor substrate 110 and alternately arranged in a second direction, a plurality of first finger electrodes 131 stacked on the back surface side of the first semiconductor layer 121 so as to extend in the first direction, and a plurality of second finger electrodes 132 stacked on the back surface side of the second semiconductor layer 122 so as to extend in the first direction, a plurality of first bus bars 141 connecting the plurality of first finger electrodes 131, and a plurality of second bus bars 142 connecting the plurality of second finger electrodes 132, and a plurality of first electrode pads 151 provided on the first bus bar 141 and a plurality of second electrode pads 152 provided on the second bus bar 142. Note that in FIG. 3, each component is hatched to make it easier to distinguish the components.

The semiconductor substrate 110 is formed of a crystalline silicon material such as single crystal silicon or polycrystalline silicon. The semiconductor substrate 110 is, for example, an n-type semiconductor substrate in which a crystalline silicon material is doped with an n-type dopant. An example of an n-type dopant is phosphorus (P). The semiconductor substrate 110 functions as a photoelectric conversion substrate that absorbs incident light from the light-receiving surface side and generates photocarriers (electrons and holes). By using crystalline silicon as the material for the semiconductor substrate 110, the dark current is relatively small, and a relatively high output (stable output regardless of illuminance) can be obtained even when the intensity of the incident light is low.

The first semiconductor layer 121 and the second semiconductor layer 122 have different conductivity types. For example, the first semiconductor layer 121 is formed of a p-type semiconductor, and the second semiconductor layer 122 is formed of an n-type semiconductor. The first semiconductor layer 121 and the second semiconductor layer 122 can be formed of, for example, an amorphous silicon material containing a dopant that imparts the desired conductivity type. An example of a p-type dopant is boron (B), and an example of an n-type dopant is phosphorus (P) as described above.

The first semiconductor layer 121 and the second semiconductor layer 122 are each formed in a strip shape extending in a first direction. In the solar cell 1, a plurality of first semiconductor layers 121 and a plurality of second semiconductor layers 122 are alternately provided in a second direction intersecting the first direction. The first semiconductor layer 121 and the second semiconductor layer 122 are preferably arranged so as to cover substantially the entire surface of the semiconductor substrate 110. The first semiconductor layer 121 and the second semiconductor layer 122 attract carriers generated in the semiconductor substrate 110 to collect charges. The first semiconductor layer 121 and the second semiconductor layer 122 can be formed in sequence by forming a mask on the back surface of the semiconductor substrate 110 and stacking semiconductor materials by a film formation technique such as CVD.

The first finger electrode 131 is laminated so as to extend in the first direction on the back side of the center part in the second direction of each first semiconductor layer 121, and the second finger electrode 132 is laminated so as to extend in the first direction on the back side of the center part in the second direction of each second semiconductor layer 122. The first finger electrode 131 and the second finger electrode 132 extract electric charges from the first semiconductor layer 121 and the second semiconductor layer 122. The first finger electrode 131 and the second finger electrode 132 may be formed, for example, by printing and firing a conductive paste such as silver paste, or may be formed, for example, by laminating a metal layer such as copper, forming a resist pattern, and selectively etching it.

The first bus bar 141 and the second bus bar 142 are formed on the back side of the first finger electrode 131 and the second finger electrode 132 so as to extend in the second direction. The first bus bar 141 is connected to the intersecting first finger electrode 131 by adhesive A1 such as conductive adhesive or solder, and is insulated from the intersecting second finger electrode 132 by, for example, a gap, an insulating material, or the like. The second bus bar 142 is insulated from the intersecting first finger electrode 131 and connected to the intersecting second finger electrode 132. The first bus bars 141 and the second bus bars 142 are each arranged at intervals in the first direction.

One or more first electrode pads 151 are provided on each of the first bus bars 141, and one or more second electrode pads 152 are provided on each of the second bus bars 142. Therefore, at least one first electrode pad 151 of each solar cell 10 has a different distance from the edge where it is overlapped with the other solar cell 10 than the other first electrode pads 151. Similarly, at least one second electrode pad 152 has a different distance from the edge where it is overlapped with the other solar cell 10 than the other second electrode pads 152. In this way, by providing the electrode pads 151, 152 at various positions on the solar cell 10, the internal resistance of the solar cell 10 is reduced, and the efficiency of the solar cell module 1 can be improved.

The first electrode pad 151 and the second electrode pad 152 may be formed of separate members laminated on the back side of the first bus bar 141 and the second bus bar 142, or may be set as specific parts of the back side of the material constituting the first bus bar 141 and the second bus bar 142.

The insulating sheet 20 has a plurality of connection openings 21 that expose the electrode pads 151, 152, respectively, to enable connection of the connection member 30 to the electrode pads 151, 152. The insulating sheet 20 preferably further has a plurality of sealing openings 22 that are filled with a sealant 60 at positions spaced apart from the electrode pads 151, 152. The insulating sheet 20 prevents damage, short circuits, etc. of the solar cell 10 by mitigating stress concentration caused by pressure contact between the solar cell 10 and between the solar cell 10 and the connection member 30 other than the electrode pads 151, 152.

The insulating sheet 20 can be formed from a resin film that does not melt or deform during the manufacture of the solar cell module 1, such as polyimide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytetrafluoroethylene (PTFE), or polyamide. The connection opening 21 and the sealing opening 22 can be formed, for example, by punching using a Thomson blade. The thickness of the insulating sheet 20 is preferably, for example, 10 μm to 200 μm, and more preferably 20 μm to 100 μm. By making the thickness of the insulating sheet 20 equal to or greater than the lower limit, damage, short circuits, and the like of the solar cell 10 can be reliably prevented. In addition, by making the thickness of the insulating sheet 20 equal to or less than the upper limit, the connection of the connection member 30 to the electrode pads 151 and 152 can be facilitated.

The insulating sheet 20 may be temporarily fixed to the solar cell 10 with an adhesive tape (not shown) or the like to prevent misalignment during the manufacturing of the solar cell module 1. Specifically, after the insulating sheet 20 is placed on the solar cell 10, an insulating adhesive tape may be applied across the solar cell 10 and the insulating sheet 20, or a double-sided tape may be applied between the solar cell 10 and the insulating sheet 20. By positioning the insulating sheet 20 in this manner, it is possible to ensure proper positioning of the insulating sheet 20, and to check the position of the insulating sheet 20 during manufacturing, and if it is inappropriate, to correct the positioning of the insulating sheet 20 by re-applying the adhesive tape. This reduces the manufacturing cost of the solar cell module 1 and improves the yield.

The connection opening 21 can prevent unnecessary spreading of the adhesive A2, such as a conductive adhesive or solder, for the connection member 30, thereby preventing short circuits caused by unintended spreading of the adhesive A2 and allowing a reduction in the amount of adhesive applied. For this reason, it is preferable to apply the adhesive A2 for connecting the connection member 30 to the electrode pads 151, 152 into the connection opening 21 after laminating the insulating sheet 20 on the back surface of the solar cell 10. The opening width of the connection opening 21 is preferably smaller than the width of the electrode pads 151, 152 to prevent the adhesive A2 from spreading to areas other than the electrode pads 151, 152.

When the space between the front surface protection member 40 and the back surface protection member 50 is sealed with the sealing material 60, the sealing opening 22 allows the sealing material 60 to flow from the sealing opening 22 into the gap between the solar cell 10 and the insulating sheet 20 to fill the gap. For this reason, it is preferable that the sealing opening 22 is formed so as to open in an area where the finger electrodes 131, 132 and the bus bars 141, 142 are not present. It is preferable that the opening width of the sealing opening 22 is larger than the opening width of the connection opening 21 so that the sealing material 60 can flow in without any gaps.

The connection member 30 may be any material that is conductive, and may be formed, for example, from a rod- or strip-shaped metal that can be bent in a stepped manner to match the steps caused by the thickness of the solar cell 10 and the insulating sheet 20. Typically, as shown in the figure, the connection member 30 connects a first electrode pad 151 of one of two solar cell cells 10 aligned in the first direction to a second electrode pad 152 of the other solar cell 10 through the corresponding connection openings 21. In order to reduce the effect of resistance resulting from the connection member 30, it is preferable to connect multiple electrode pads 151, 152 together using multiple connection members 30.

The surface protection member 40 protects the solar cell 10 by covering the surface of the solar cell 10 via the sealing material 60. The surface protection member 40 can be formed from a plate-like or sheet-like material, and preferably has excellent light transmissivity and weather resistance. Specifically, examples of the material for the surface protection member 40 include transparent resins such as acrylic resins or polycarbonate resins, and glass. In addition, the surface of the surface protection member 40 may be processed to have an uneven shape or coated with an anti-reflective coating layer in order to suppress light reflection.

The back surface protection member 50 covers and protects the back surface of the solar cell 10 via the sealing material 60. The back surface protection member 50 can be formed from a plate-like or sheet-like material, similar to the front surface protection member 40, and preferably has excellent water impermeability. Specifically, examples of the back surface protection member 50 include resin films such as polyethylene terephthalate, polyethylene (PE), olefin resins, fluorine-containing resins, and silicone resins, laminates of the resin films and metal foils such as aluminum foils, transparent resins such as acrylic resins or polycarbonate resins, and glass.

The sealing material 60 adheres the solar cell 10, the insulating sheet 20, the front surface protection member 40, and the back surface protection member 50 together, and also protects the solar cell 10 by eliminating gaps around the solar cell 10. In particular, the sealing material 60 prevents moisture from coming into contact with the solar cell 10. For this reason, the sealing material 60 is preferably a thermoplastic resin having translucency, such as ethylene/vinyl acetate copolymer (EVA), ethylene/α-olefin copolymer, ethylene/vinyl acetate/triallyl isocyanurate (EVAT), polyvinyl butyrate (PVB), acrylic resin, urethane resin, or silicone resin.

The sealing material 60 can be formed by placing a sheet-like material between the string consisting of the solar cell 10, the insulating sheet 20, and the connection member 30 and the front surface protection member 40 and between the rear surface protection member 50, and by fluidizing these two sheets of material using a heat press to integrate them in the gaps between the strings.

As described above, the solar cell module 1 has an insulating sheet 20 that covers the back surface of each solar cell 10, and therefore can prevent, for example, excessive stress during the hot pressing during manufacturing, which could damage the solar cell 10, or the connection member 30 from contacting parts of the solar cell 10 other than the intended electrode pads 151, 152, which could cause a short circuit. This makes the solar cell module 1 highly reliable. Furthermore, because one insulating sheet 20 can prevent damage and short circuits in the entire solar cell 10, the solar cell module 1 has a simple configuration and can be manufactured inexpensively.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and variations are possible.

For example, in the solar cell module according to the present invention, the solar cell is not limited to the configuration of the above embodiment, and may have, for example, a comb-shaped semiconductor layer and electrode, and may have a configuration of, for example, an intrinsic semiconductor layer, an insulating layer, a further electrode layer, an anti-reflection film, etc.

In the solar cell module of the present invention, the sealing opening in the insulating sheet may be omitted, or an insulating sheet having a layer of the same material or adhesive as the sealing material on the solar cell side may be used instead of the sealing opening.

REFERENCE SIGNS LIST 1 Solar cell module 10 Solar cell 20 Insulating sheet 21 Connection opening 22 Sealing opening 30 Connection member 40 Front surface protection member 50 Back surface protection member 60 Sealing material 110 Semiconductor substrate 121 First semiconductor layer 122 Second semiconductor layer 131 First finger electrode 132 Second finger electrode 141 First bus bar 142 Second bus bar 151 First electrode pad 152 Second electrode pad A1, A2 Adhesive

Claims (3)

A plurality of solar cells each having a plurality of electrode pads on a rear surface side and arranged such that ends in a first direction overlap each other;
a plurality of insulating sheets formed from a sheet-like material arranged one-to-one with the plurality of solar cells so as to cover the back surfaces of the plurality of solar cells, the insulating sheets having a plurality of connection openings exposing the plurality of electrode pads, respectively;
a plurality of connection members that connect the electrode pads of the adjacent solar cells through the connection openings;
Equipped with
The insulating sheet further has a sealing opening, which is filled with a sealing material, at a position spaced from the electrode pad . The solar cell module according to claim 1, wherein the distance from the edge of at least one of the electrode pads that overlaps with the other solar cell is different from the other electrode pads in the solar cell. The solar cell comprises:
A semiconductor substrate;
a plurality of first semiconductor layers and a plurality of second semiconductor layers having different conductivity types, each of which is formed in a strip shape extending in a first direction on a rear surface of the semiconductor substrate and alternately arranged in a second direction intersecting the first direction;
a plurality of first finger electrodes stacked on a rear surface side of the first semiconductor layer so as to extend in the first direction, and a plurality of second finger electrodes stacked on a rear surface side of the second semiconductor layer so as to extend in the first direction;
a first bus bar connecting the first finger electrodes and a second bus bar connecting the second finger electrodes;
Equipped with
The solar cell module according to claim 1 , wherein the electrode pad is provided on the first bus bar or the second bus bar.

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