JP2011077103A - Solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell module in which power generation efficiency of the solar cell module per unit area is raised with improved reliability. <P>SOLUTION: The solar cell module includes: a first solar cell element 1 and a second solar cell element 2, containing a substrate having a first surface and a second surface corresponding to the rear side of the first surface as well as a rear surface electrode formed on the second surface; and a connection conductor 3 which electrically connects a rear surface electrode 7 of the first solar cell element 1 and a rear surface electrode 7' of the second solar cell element 2 together. The first solar cell element 1 is arranged such that a part of second surface 1b of the first solar cell element 1 overlaps with a part of first surface 2a of the second solar cell element 2 through an insulating part 8. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a solar cell module.

  As shown in FIG. 5, the conventional solar cell module transmits a solar cell element array (solar cell string 21) formed by connecting a plurality of solar cell elements 20 made of a single crystal silicon substrate or a polycrystalline silicon substrate in series. Sandwiched between the conductive substrate 22 and the back sheet 23, and the solar cell element array is sealed with the filler 24.

  Such solar cell modules are connected by connecting conductors or the like by providing a gap so that adjacent solar cell elements 20 do not directly contact each other. Since the solar cell element 20 is not disposed in the gap portion, the gap does not contribute to power generation (non-power generation region). Therefore, in such a solar cell module, by providing the said gap | interval part, the area (electric power generation area | region) which contributes to the electric power generation with respect to the light reception area of a solar cell module becomes small.

  Therefore, in order to reduce the non-power generation region, the solar cell elements adjacent to each other are arranged so that they overlap each other, and the surface electrode of one solar cell element and the back electrode of the other solar cell element are connected only by solder. (See Patent Document 1).

JP 59-003980 A

  However, when the solar cell module is used in an environment where the temperature change is large, the solar cell element or the filler expands / contracts according to the temperature change, and the shear stress is applied to the solder. In some cases, the solder concentrates and cracks occur in the solder, or the electrode portion to which the solder is bonded may peel off.

  The present invention has been made in view of such problems, and its purpose is to increase the power generation efficiency by increasing the power generation area with respect to the light receiving area of the solar cell module while improving the reliability. It is to provide.

  A solar cell module of the present invention includes a first solar cell element having a substrate having a first surface and a second surface corresponding to the back surface of the first surface, and a back electrode formed on the second surface; A solar cell module comprising: a second solar cell element; and a connection conductor that electrically connects the back electrode of the first solar cell element and the back electrode of the second solar cell element, The solar cell element is arranged such that a part of the second surface of the first solar cell element overlaps with a part of the first surface of the second solar cell element via an insulating part. .

  According to the solar cell module of the present invention, in the structure in which the back electrodes of the adjacent first and second solar cell elements are electrically connected to each other, the insulating portion as described above is provided. It is possible to suppress the occurrence of leakage current caused by the contact between the back electrode disposed on the second surface of the first surface and the first surface of the second solar cell element. Furthermore, in the present invention, a part of the solar cell elements are arranged so as to overlap each other, and the gap between adjacent solar cell elements is eliminated, thereby increasing the power generation area in the light receiving area of the solar cell module and increasing the power generation efficiency. be able to.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of a solar cell module of the present invention, where (a) is a schematic diagram schematically showing a cross section, and (b) is a portion for explaining a solar cell element connection structure of the present embodiment. It is a perspective view. It is the schematic diagram which represented typically the cross section of other embodiment of the solar cell module of this invention. It is the schematic diagram which represented typically the cross section of other embodiment of the solar cell module of this invention. It is the schematic diagram which represented typically the cross section of other embodiment of the solar cell module of this invention. It is explanatory drawing for demonstrating the conventional solar cell module.

  An embodiment of a solar cell module of the present invention will be described with reference to the drawings.

  The solar cell module according to an embodiment of the present invention includes a plurality of solar cell elements including the first solar cell element 1 and the second solar cell element 2 and adjacent solar cells, for example, the first solar cell element 1 and It has the connection conductor 3 which electrically connects the 2nd solar cell element 2, the translucent board | substrate 4, the back surface sheet 5, and the filler 6. FIG.

  The solar cell elements (the first solar cell element 1 and the second solar cell element 2) are mainly the first surface (the first surface 1a of the first solar cell element 1 and the first of the second solar cell elements 2) which are the light receiving surfaces. Surface 2a) and a second surface corresponding to the back surface of the first surface (second surface 1b of first solar cell element 1, second surface 2b of second solar cell element 2). The solar cell element has a function of converting light incident from the outside into electricity. Therefore, the solar cell element has a PN junction made of at least one semiconductor inside. Such a solar cell element may be any element having a photoelectric conversion function. For example, a polycrystalline or single crystal silicon substrate, an amorphous silicon thin film, or a compound thin film such as CIGS can be selected.

  Moreover, the back surface electrode is formed in the 2nd surface at the solar cell element. That is, in the first solar cell element 1, the back surface electrode 7 is formed on the second surface 1b, and in the second solar cell element 2, the back surface electrode 7 'is formed on the second surface 2b.

The back electrode has a function of collecting carriers generated in the solar cell element. In the present embodiment, both the positive electrode and the negative electrode are provided on the second surface (back surface) of each solar cell element. However, the surface electrode is provided on the first surface of the solar cell element. A structure may be adopted in which the carriers collected on one surface side are guided to the back electrode on the second surface. As the material for the back electrode 4, for example, a conductive material such as copper, silver, or aluminum is preferably used. And the back electrode 4 can be formed by apply | coating these to the desired position of a solar cell element by vapor deposition or screen printing, and baking.

  The connection conductor 3 has a function of electrically connecting back electrodes of adjacent solar cell elements. In the present embodiment, the back electrode 7 of the first solar cell element 1 and the back electrode 7 'of the second solar cell element 2 are connected. More specifically, the positive electrode of the back electrode 7 of the first solar cell element 1 and the negative electrode of the back electrode 7 ′ of the second solar cell element 2 are connected. In addition, the connection conductor 3 should just connect the back surface electrodes which have different polarities, the negative electrode of the back surface electrode 7 of the 1st solar cell element 1, and the positive electrode of back surface electrode 7 'of the 2nd solar cell element 2. May be connected. The connection conductor 3 is electrically connected to the back electrode via solder. For example, the connection conductor 3 is formed by covering a long copper foil having a width of about 1 to 3 mm and a thickness of about 0.1 to 0.8 mm with a dip or the like. Therefore, the connection conductor 3 can be bonded by applying heat after being disposed on the back electrode to be bonded.

  The translucent board | substrate 4 is arrange | positioned at the light-receiving surface side of a solar cell module, and has a role which protects a solar cell element. Examples of such a translucent substrate 2 include glass such as white plate glass, tempered glass, laminated glass, and heat ray reflective glass, or synthetic resins such as polycarbonate resin and acrylic resin, and the solar cell element can be photoelectrically converted. The member is not particularly limited as long as it is a member that can transmit light of various wavelengths. Moreover, as thickness of the translucent board | substrate 2, for example, it is preferable that thickness is about 3 mm-5 mm if it is glass, and thickness is about 5 mm-8 mm if it is a synthetic resin.

  The back sheet 5 has a role of protecting the filler 6 and the solar cell element. For the back sheet 7, for example, PVF (polyvinyl fluoride), PET (polyethylene terephthalate) PEN (polyethylene naphthalate), or a laminate of these can be used.

  The filler 6 has a role of sealing the solar cell element. As such a filler 6, for example, an ethylene vinyl acetate copolymer (EVA) or polyvinyl butyral (PVB) as a main component is formed into a sheet having a thickness of about 0.4 to 1 mm by an extruder. Is used. And what was shape | molded in the sheet form is cut | disconnected to a desired magnitude | size, and a solar cell element is inserted | pinched from the 1st surface side and the 2nd surface side, and is sealed.

  The filler 6 contains a crosslinking agent. This crosslinking agent has a role of bonding between molecules such as EVA, and is, for example, an organic peroxide that decomposes at a temperature of 70 to 180 ° C. to generate radicals. Examples of the organic peroxide include 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, tert-hexylperoxypivalate and the like, and about 1 part by mass with respect to 100 parts by mass of EVA. It is preferable to make it contain in a ratio.

  In addition to the EVA and PVB described above, the filler 6 can be suitably used as long as it is a thermosetting resin or a resin that contains a crosslinking agent in a thermoplastic resin and has a thermosetting property. For example, acrylic resin, silicon resin, epoxy resin, EEA (ethylene-ethyl acrylate copolymer), and the like can be used.

  And in this embodiment, as shown to Fig.1 (a), as for the 1st solar cell element 1, a part of 2nd surface 1b of this 1st solar cell element 1 is the 1st of the 2nd solar cell element 2. As shown in FIG. It arrange | positions so that it may overlap with a part of surface 2a via the insulation part 8. FIG. That is, in this embodiment, it arrange | positions so that a 1st and 2nd solar cell element may be tiled. In the present embodiment, when the solar cell modules are viewed in plan, the first solar cell elements 1 and the second solar cell elements 2 in the same row can be arranged without gaps, so that the power generation area per light receiving area of the solar cell modules is increased. And a large amount of generated power can be obtained. Moreover, as a magnitude | size of the area | region which overlaps when planarly viewing a 1st and 2nd solar cell element, about 0.5 mm-2 mm from an element edge part is the shadow of the 2nd solar cell element 2 by the 1st solar cell element 1. FIG. This is preferable from the viewpoint of reducing the loss.

  Moreover, the insulation part 8 in this embodiment suppresses the contact between the back surface electrode 7 of the first solar cell element 1 and the first surface 2a of the second solar cell element 2, and prevents the occurrence of leakage current caused by the contact. Have a role to play. That is, the insulation part 8 should just be arrange | positioned so that the said contact may be suppressed, and the 1st solar cell element 1 and a 2nd solar cell element overlap in planar view of a solar cell element (solar cell module). It may be arranged on the entire surface of the part, or as shown in FIG. If the insulation part 8 is a form which provides the 1st solar cell element 1 and the 2nd solar cell element in the whole surface of an overlapping part, generation | occurrence | production of a leakage current can be reduced more efficiently. Moreover, you may arrange | position the insulation part 8 so that the 1st solar cell element 1 and the 2nd solar cell element may become larger than the overlapping part. On the other hand, the form which provides the insulation part 8 in a part of overlap part with the 1st solar cell element 1 and the 2nd solar cell element is suitable from a viewpoint that a number of parts can be decreased.

  As such an insulating part 8, for example, a resin excellent in heat resistance and weather resistance is preferable. In addition, when EVA is used for the filler 6, it may be an insulating material that can withstand the lamination / crosslinking temperature (160 to 200 ° C.) of EVA, and resin molding such as ceramic and epoxy adhesives and acrylic and polycarbonate. It may be a product. Further, if polyethylene terephthalate, polyethylene naphthalate, polyvinyl fluoride, polyimide, and polytetrafluoroethylene are selected as the resin, water resistance can be increased, which is preferable from the viewpoint of reducing deterioration of dielectric strength performance. is there. Further, the shape of the insulating portion 8 is not particularly limited, but a tape shape is preferable from the viewpoint of easy manufacture. In the case of such a tape shape, the thickness of the insulating portion 8 is preferably about 100 μm to 500 μm from the viewpoint of simplifying the manufacturing process while realizing insulation between the solar cell elements.

  The insulating portion 8 may have an adhesive action that fixes the first and second solar cell elements to each other. Thus, if the insulating part 8 which has an adhesive effect | action which fixes a solar cell element is used, it is suitable from a viewpoint that the position shift of a solar cell element can be reduced. The insulating portion 8 having an adhesive action is an adhesive such as ceramic or epoxy as described above. Since such an adhesive is a softer material than solder, the concentration of shear stress caused by expansion or contraction of the solar cell element due to temperature change can be reduced.

  On the other hand, if the insulating part 8 having no adhesive action is used, even if the solar cell element is expanded or contracted by heat, the shear stress generated by the expansion or contraction can be reduced from acting on the insulating part 8. Moreover, generation | occurrence | production of the crack of the insulation part 8 can be suppressed. Examples of the insulating portion 8 having no adhesive action include polyethylene terephthalate, polyethylene naphthalate, polyvinyl fluoride, polyimide, polytetrafluoroethylene, acrylic, and polycarbonate as described above.

  Moreover, as shown in FIG. 3, the insulating part 8 can be substituted by using an insulating filler 6. That is, in such a form, the filler 6 which has insulation is arrange | positioned in the overlap part of the 1st solar cell element 1 and the 2nd solar cell element. As such a filler 6, for example, EVA or PVB as described above is suitable. Thus, if the filler 6 which has insulation is used, since the filler 6 functions not only as a sealing of a solar cell element but as an insulation part, the number of parts can be reduced. In addition, since the refractive index of the overlapping portion between the first solar cell element 1 and the second solar cell element and the refractive index of the portion where the other filler 6 is disposed can be made the same, the incident light Unnecessary scattering can be reduced.

  Further, in the embodiment shown in FIG. 3, the insulating portion 8 is substituted by the insulating filler 6, but the insulating portion 8 is constituted by the filler 6 and another insulating portion. Also good. As such a configuration, a plurality of spacers in which the insulating portions 8 are arranged with a space therebetween, and an insulating filler 6 between the adjacent spacers are arranged. According to such a form, since the contact between the solar cell elements can be prevented in advance by the spacer at the time of manufacturing the solar cell module, it is possible to reduce cracks and the like generated in the substrate and before the filler is filled. It can prevent that a solar cell element contacts. For example, the spacer may be made of the same material as the insulating portion 8 described above.

  In addition, the insulating portion 8 may be a gap portion 8 'as shown in FIG. If the insulating portion 8 is configured by such a gap portion 8 ′, the generation of leakage current can be reduced, and even if the solar cell element is expanded or contracted by heat, the shear stress generated by the expansion or contraction is reduced. Since it is not affected, long-term reliability can be improved.

  Next, an example of the manufacturing method of the solar cell module according to one embodiment of the present invention shown in FIG. 1 will be described.

  First, one end of the connection conductor 3 is connected to the back electrode 7 ′ of the second solar cell element 2 with solder or the like. Next, the first solar cell element 1 is placed so that the second surface 1b faces upward, and the insulating portion 8 is provided on the second surface 1b of the first solar cell element 1 which is a portion overlapping the second solar cell element 2. Place. Next, the overlapping portion of the second solar cell element 2 is placed on the insulating portion 8, and the connection conductor 3 extending from the second solar cell element 2 and the back electrode 7 of the first solar cell element 1 are soldered or the like. Connecting. By repeating this process, a plurality of solar cell elements are electrically connected by connecting conductors to form a solar cell string.

  Subsequently, the filler 6 is laminated | stacked on the translucent board | substrate 4, and the light-receiving surface of the solar cell string mentioned above is laminated | stacked toward the translucent board | substrate 4 side. On top of that, another sheet of filler 6 is further laminated, the solar cell string is sandwiched between the pair of fillers 6, and then the back sheet 5 is laminated. Finally, the laminate 6 is heated and pressed under reduced pressure to soften and fuse the filler 6 on the translucent substrate side and the filler 6 on the back sheet 5 side to seal the solar cell string. While stopping, all the members are integrated to produce a solar cell module.

1: first solar cell element 1a: first surface 1b of first solar cell element: second surface of first solar cell element 2: second solar cell element 2a: first surface 2b of second solar cell element: first 2 Second surface 3 of solar cell element 3: Connection conductor 4: Translucent substrate 5: Back sheet 6: Filler 7, 7 ′: Back electrode 8: Insulating part 8 ′: Air gap part

Claims (5)

A first solar cell element and a second solar cell element, each including a substrate having a first surface and a second surface corresponding to the back surface of the first surface; and a back electrode formed on the second surface;
A solar cell module comprising: a connection conductor that electrically connects a back electrode of the first solar cell element and a back electrode of the second solar cell element;
The first solar cell element is disposed so that a part of the second surface of the first solar cell element overlaps a part of the first surface of the second solar cell element via an insulating portion. A featured solar cell module.   The solar cell module according to claim 1, wherein the insulating portion includes at least one of polyethylene terephthalate, polyethylene naphthalate, polyvinyl fluoride, polyimide, and polytetrafluoroethylene. A filler for sealing the first solar cell element and the second solar cell element;
The filler has an insulating property,
The solar cell module according to claim 1, wherein the insulating part includes the filler.   The said insulating part includes a plurality of spacers and the filler that are arranged apart from each other, and the filler is arranged between the adjacent spacers. Solar cell module.   The solar cell module according to claim 1, wherein the insulating portion is a gap.

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