JP2010109099A - Solar battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar battery module capable of preventing cell strings from peeling more from each other. <P>SOLUTION: The solar battery module 1 includes cell strings 3A, 3B and 3C formed by connecting power generating elements 2, a sealing material 6 for sealing the power generating elements 2, and a surface protecting member 7 and a backside protecting member 8 bonded to a light receiving surface side and a backside of the sealing material 6. The sealing material 6, surface protecting member 7 and a bonding surface have a convex and a concave portions arranged alternately among the cell strings 3A, 3B and 3C to be formed in a corrugated shape. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solar cell module that converts solar energy into electrical energy.

Conventionally, as a technique in such a field, for example, one described in Japanese Patent Application Laid-Open No. 2005-72567 is known. The solar cell module described in this publication includes cell strings formed by connecting power generation elements, surface sealing material films and back surface sealing material films, and surface sealing material films disposed on the front and back surfaces of the cell strings. A surface protection member to be bonded is provided. Then, by providing a groove on at least one surface of the front surface sealing material film and the back surface sealing material film, bubbles inside the module are removed during thermocompression bonding of the power generating element and the sealing material film, and the solar cell module The appearance has been improved.
JP-A-2005-72567

  In order to reduce the weight of the solar cell module, a method using a transparent plastic material for the surface protection member is cited. However, since the plastic material has a much larger linear expansion coefficient than that of glass (see FIG. 14), the plastic material undergoes a large thermal contraction due to a temperature difference between seasons and day and night. As a result, as shown in FIG. 15, a large stress is generated at the interface (that is, the adhesive surface) between the surface protection material 31 and the sealing material 32, and the separation S occurs. When the separation S occurs at the interface, water vapor enters the portion and the sealing material 32 becomes cloudy, leading to a decrease in the amount of light incident on the power generation element 33, which causes a decrease in power generation performance. Furthermore, there is a problem that the peeling S gradually advances to the periphery, and the power generation performance of the surrounding power generation element 33 is deteriorated.

  In order to solve such a problem, when peeling occurs, it is necessary to take measures to prevent the progress of peeling. However, in the conventional solar cell module, measures for preventing the peeling progress have not been studied. For this reason, for example, as shown in FIG. 16A, when a separation S occurs in the middle cell string among the three cell strings arranged side by side, the separation S spreads to the adjacent left side cell strings. (See FIG. 16 (b)), there was a problem that the output performance of the left cell string was lowered, and as a result, the overall output of the solar cell module was lowered.

  Therefore, the present invention has been made to solve such a technical problem, and an object thereof is to provide a solar cell module capable of preventing the progress of peeling between cell strings.

  That is, the solar cell module according to the present invention includes a plurality of cell strings formed by connecting a plurality of power generating elements, a sealing material for sealing the plurality of cell strings, and a light receiving surface side of the sealing material. A surface protection member to be bonded and a back surface protection member bonded to the back surface side of the sealing material, and a bonding surface between the surface protection member and the sealing material is formed in an uneven shape between the cell strings. It is characterized by being.

  According to this invention, since the joint surface between the surface protection member and the sealing material is formed in an uneven shape between the cell strings, if the cell strings peel off, the uneven shape is adjacent to It is possible to prevent the progress of peeling to the cell strings. Accordingly, it is possible to suppress a decrease in the overall output of the solar cell module due to the progress of peeling.

  Moreover, in the solar cell module according to the present invention, the joint surface between the surface protection member and the sealing material is formed in a wave shape by alternately arranging the convex portions and the concave portions between the cell strings. Is preferred.

  According to this invention, compared with the case where it forms in a saw shape, for example, the wettability of a joint surface can be improved and adhesiveness can be improved. As a result, the bonding strength of the bonding surface can be increased and the occurrence of peeling can be prevented. Further, since the joining surface is formed in a wave shape, an optical confinement effect on the joining surface can be expected.

  In the solar cell module according to the present invention, 1/2 of the distance from the top of the adjacent convex portion to the bottom of the concave portion in the height direction of the convex portion is H, and adjacent in the juxtaposed direction of the convex portion and the concave portion. It is preferable that the relational expression H / L ≦ 1.0 is satisfied, where L is a half of the distance from the top of the convex portion to the bottom of the concave portion.

  According to the present invention, it is possible to reduce the stress generated on the bonding surface and increase the bonding strength.

  In the solar cell module according to the present invention, it is preferable that the plurality of cell strings are separated by a bypass diode.

  According to the present invention, heat generation can be prevented when a shadow is partially generated on the solar cell module.

  ADVANTAGE OF THE INVENTION According to this invention, the solar cell module which can prevent progress of peeling between cell strings can be provided.

  Hereinafter, preferred embodiments of a solar cell module according to the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  1 is a plan view of the solar cell module according to the embodiment, FIG. 2 (a) is a cross-sectional view taken along line II in FIG. 1, and FIG. 2 (b) is taken along line II-II in FIG. It is sectional drawing which follows. The solar cell module 1 according to the present embodiment includes three cell strings 3A, 3B, 3C formed by connecting a plurality of power generating elements 2. These cell strings 3A, 3B, 3C are connected in parallel and separated by bypass diodes 4a, 4b, 4c.

  The power generating elements 2 are arranged at equal intervals in the vertical direction and the horizontal direction. These power generating elements 2 receive sunlight and convert the received light energy into electric energy, and are also called photoelectric conversion elements or solar cells. The power generating element 2 is made of general-purpose single crystal silicon formed in a square shape having a side of about 100 to 150 mm, for example.

  The plurality of power generation elements 2 arranged in the vertical direction are connected in series via an interconnector 5. The interconnector 5 is a conductive member for electrically connecting the power generating element 2 and has a substantially rectangular cross section. As shown in FIG. 1, six power generating elements 2 arranged in a 3 × 2 grid are connected in series by an interconnector 5 to form cell strings 3A, 3B, and 3C.

  As shown in FIG. 2, the power generating element 2, the interconnector 5, and the bypass diodes 4 a, 4 b, 4 c are sealed in a thin plate-shaped sealing material 6. A flat surface protection member 7 is bonded to the light receiving surface side of the sealing material 6, that is, the light receiving surface side of the power generation element 2, and a back surface protection member 8 is bonded to the back surface side of the sealing material 6. The sealing material 6, the surface protection member 7, and the back surface protection member 8 are integrally formed.

  As a material for the sealing material 6, a synthetic resin having a light-transmitting property, high adhesive strength, and excellent heat resistance is preferable. For example, ethylene-vinyl acetate copolymer resin (EVA) or highly transparent polyvinyl butyrol (PVB) can be used.

  The surface protection member 7 is made of a rectangular plastic material having weather resistance, and protects the power generating element 2, the interconnector 5, and the like from destruction due to physical impact or erosion due to rain or gas. The surface protection member 7 has translucency similarly to the sealing material 6 described above, so that sunlight can be efficiently received by the light receiving surface of the power generation element 2. As the surface protection member 7, for example, a plastic material such as acrylic resin or polycarbonate is used, and the solar cell module 1 is reduced in weight.

  The surface protection member 7 may be any light material having translucency. For example, polyethylene terephthalate, polybutylene terephthalate, polyvinyl acetate, polyvinyl fluoride, polyethylene naphthalate, Polyacrylonitrile, unsaturated polyester resin, epoxy resin, polyarylate, polyetherimide, polyimide, polyurethane, butyral resin, ETFE, polyethersulfone, ABS resin, or the like may be used.

  Of the above plastic materials, polycarbonate, acrylic resin, polyethylene terephthalate, ETFE, and ABS resin are preferable from the viewpoint of high light transmittance, heat resistance, impact resistance, and the like. More preferred are polycarbonate and acrylic resin from the viewpoints of versatility and moldability.

  The back surface protection member 8 is made of a weather-resistant plastic material such as polyvinyl fluoride (PVF), and protects the power generating element 2 and the interconnector 5 from damage or erosion due to physical impact, like the surface protection member 7. To do.

  As shown in FIG. 1, a positive electrode 9 a and a negative electrode 9 b for taking out the electric power generated by the power generation element 2 to the outside are arranged at one end of the solar cell module 1.

  Between the cell strings 3A, 3B, 3C, the bonding surface between the sealing material 6 and the surface protection member 7 is processed into an uneven shape, and an uneven region 10 is formed. FIG. 3 is a partially enlarged view of the uneven area. As shown in FIG. 3, the concavo-convex region 10 is formed in a smooth wave shape by arranging a plurality of concave portions and convex portions alternately and continuously.

  Then, ½ of the distance from the top of the convex portion adjacent in the height direction of the convex portion to the bottom of the concave portion is H, and from the top of the convex portion adjacent in the juxtaposing direction of the convex portion and the concave portion to the bottom of the concave portion The relational expression of H / L ≦ 1.0 is satisfied when ½ of the distance up to is L.

  Hereinafter, the meaning of the above relational expression will be described with reference to FIGS. 4 and 5.

  FIG. 4 is a diagram showing a comparison between a solar cell module sealing material and a general adhesive. A sealing material (that is, an adhesive) used in a solar cell has a Young's modulus smaller than that of a general adhesive (for example, an epoxy type) and is softer than a general adhesive. The reason is that, in the case of a hard material, when the solar cell module is deformed, a large stress is generated in the power generating element and cracks. When the hardness of the adhesive is different, the interfacial stress distribution in the bonding between the two materials is greatly different. In the case of the sealing material, it is necessary to optimize the uneven shape of the interface (that is, the adhesive surface).

  It is considered that the interface shape is preferably a curved surface shape (ie, a wave shape) without a point from the viewpoint of stress concentration. The inventor of the present application divided H / L = 0, H / L = 0.2, H / L = 0.5, and H / L = 1.0, and investigated the relationship between each and the interface generated stress. The result is shown in FIG. As shown in FIG. 5, it was found that at H / L ≦ 1.0, the curved interface has a lower interface generation stress than the planar interface. Therefore, when H / L ≦ 1.0, the adhesive strength can be increased.

  In the solar cell module 1 configured as described above, the adhesive surface between the sealing material 6 and the surface protection member 7 is formed in a wave shape between adjacent cell strings 3A, 3B, 3C, and the uneven region 10 is formed. The uneven region 10 can prevent the peeling generated in the cell strings 3A, 3B, 3C from progressing to the adjacent cell strings 3A, 3B, 3C.

  For example, as shown in FIG. 6A, the separation S occurs in the middle cell string 3B among the cell strings 3A, 3B, 3C, and the separation S progresses to the adjacent cell strings 3A and 3C. Since the uneven area 10 is provided between the cell strings 3A and 3B and between the cell strings 3B and 3C, the progress of the separation S is prevented by the uneven area 10, and the separation S is adjacent to the adjacent cell strings 3A. And cannot spread to 3C (see FIG. 6B).

  By providing the concavo-convex region 10 in this manner, even if the separation S occurs in the cell strings 3A, 3B, 3C, the progress to the adjacent cell strings due to the separation S can be reliably prevented. As a result, it is possible to suppress a decrease in the overall output of the solar cell module 1 due to the progress of peeling.

  Moreover, since the uneven | corrugated area | region 10 is formed in the waveform by arranging a several convex part and a recessed part alternately in parallel, compared with the case where an adhesive surface is formed in saw shape, for example, the wettability of an adhesive surface is improved. In addition to improving, it is possible to improve adhesion. For example, as shown in FIG. 7, when the surface protection member 7 a is formed in a saw shape, the resin of the sealing material 6 a is not easily entered, and an unbonded portion (that is, a gap) T is generated. On the other hand, when the adhesive surface is formed in a wave shape, the resin of the sealing material 6 is easy to enter and the adhesiveness is high. As a result, the adhesive strength of the adhesion can be increased, and the occurrence of peeling can be prevented. In addition, since the adhesive surface is formed in a wave shape, a light confinement effect on the adhesive surface can also be expected.

  Further, ½ of the distance from the top of the convex portion adjacent in the height direction of the convex portion to the bottom of the concave portion is H, and the bottom of the concave portion from the top of the convex portion adjacent in the juxtaposition direction of the convex portion and the concave portion Since the relational expression H / L ≦ 1.0 is satisfied when 1/2 of the distance to L is L, the stress generated on the adhesive surface between the sealing material 6 and the surface protection member 7 should be reduced. It is possible to increase the adhesive strength.

  Further, since the cell strings 3A, 3B, and 3C are partitioned by the bypass diodes 4a, 4b, and 4c, heat generation can be prevented when the solar cell module 1 is partially shaded.

  FIG. 8 is a cross-sectional view showing a solar cell module formed in a concavo-convex shape on the entire bonding surface between the sealing material and the surface protection member. As shown in FIG. 8, the solar cell module 11 includes a plurality of power generation elements 12, an interconnector 13 that connects the plurality of power generation elements 12 in series, a sealing material 14 that seals the power generation elements 12 and the interconnector 13, A surface protection member 15 bonded to the light receiving surface side of the stopper 14 and a back surface protection member 16 bonded to the back surface of the sealing material 14 are provided. The six power generation elements 12 arranged in a row form a cell string 18 by being connected in series by a plurality of interconnectors 13.

  The adhesive surface between the sealing material 14 and the surface protection member 15 is formed in a smooth wave shape by arranging a plurality of concave portions and convex portions alternately and continuously over the entire surface. Then, ½ of the distance from the top of the convex portion adjacent in the height direction of the convex portion to the bottom of the concave portion is H, and from the top of the convex portion adjacent in the juxtaposing direction of the convex portion and the concave portion to the bottom of the concave portion The relational expression of H / L ≦ 1.0 is satisfied when ½ of the distance up to is L. The sealing material 14, the surface protection member 15, and the back surface protection member 16 are formed of the same material as the above-described sealing material 6, surface protection member 7, and back surface protection member 8.

  Hereinafter, the manufacturing method of the solar cell module 11 will be described with reference to FIGS.

  First, an uneven shape is formed on the surface protection member 15. For example, as shown in FIG. 9 (a), the surface protection member 15 having the irregular shape formed thereon is pressed by pressing the mold 17 manufactured by the nanoimprint technology against the surface protection member 15 in an environment at or above the heat deformation temperature. It is manufactured (see FIG. 9B).

  Next, a laminating process is performed using the surface protection member 15 having the uneven shape. For example, as shown in FIG. 10, after the surface protection member 15, the sealing material 14a, the cell strings 18, the sealing material 14b, and the back surface protection member 16 are set in this order on the laminate base 19, the sealing material 14 is heated. The cell strings 18 are formed into a sealed module by melting with. Thereby, the solar cell module 11 is manufactured. In FIG. 10, F indicates a light receiving direction.

  In addition, the manufacturing method of the solar cell module 11 is not restricted to what was mentioned above. For example, a method shown in FIG. 11 may be used as a method of forming the uneven shape on the surface protection member. That is, when a sheet-shaped or plate-shaped surface protection member is molded using the injection molding machine 20, a concave-convex shape is given in advance to the bottom surface of the mold cavity 21 and resin injection molding is performed to provide a concave-convex surface. The protection member 15 can be easily obtained.

  The manufacturing method of the solar cell module 11 has been described above, but the above-described manufacturing method is similarly applied to the manufacturing of the solar cell module 1.

  Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the following examples.

Example 1
FIG. 12 is a diagram illustrating an example of the solar cell module according to the embodiment. First, an uneven shape was formed on the surface protection member 7 using the above-described injection molding machine 20 and the mold cavity 21 (see FIG. 11). At this time, in consideration of the arrangement position of the cell strings 3A, 3B, 3C, an uneven shape was provided at a position corresponding to the surface protection member 7. In addition, as the surface protection member 7, a polycarbonate resin (Mitsubishi Engineering Co., Ltd., Iupilon S-2000, thickness 6 mm) was used.

  Next, the above-described laminating process (see FIG. 10) was performed using the surface protection member 7 on which the uneven shape was formed, and the solar cell module 1 was manufactured. At this time, the back surface protection member 8 was a rectangular sheet having a size of 1300 mm × 900 mm, and PVF (manufactured by DuPont, Tedlar (registered trademark) TTR10AH9, thickness 25 μm) was used as the material thereof.

  As the sealing material 6, an ethylene-vinyl acetate copolymer (manufactured by Mitsui Chemicals, Fabro, SC-50B, thickness 1.2 mm) was used. A 125 mm square single crystal Si cell (thickness: 200 μm) was used as the power generation element 2, and a solder-plated rectangular wire (A-TPS, manufactured by Hitachi Cable Finetech Co., Ltd.) was used as the interconnector 5.

  In the solar cell module 1, 48 power generating elements 2 are arranged in a grid of 8 rows and 6 columns to form cell strings 3A, 3B, and 3C. These power generating elements 2 are arranged in a region which is 143 mm inside from the end surface of the back surface protection member 8 in the vertical direction and 67 mm from the end surface of the back surface protection member 8 in the left and right direction. The cell strings 3A, 3B, 3C are connected in series and separated by a bypass diode.

  Adjacent cell strings 3A and 3B, 3B and 3C are arranged with an interval of 5 mm, respectively. As shown in FIG. 12, the distance between the power generation element 2 arranged at the right end of the cell strings 3A and the power generation element 2 arranged at the left end of the cell strings 3B is 5 mm. In each of the cell strings 3A, 3B, 3C, the power generating elements 2 are arranged with an interval of 2 mm between the vertical direction and the horizontal direction.

  In addition, between the cell strings 3A, 3B, 3C, the bonding surface between the sealing material 6 and the surface protection member 7 is processed into a concavo-convex shape, and a concavo-convex region 10 is formed. This uneven | corrugated area | region 10 is formed in the smooth wave shape by arranging in parallel several recessed part and a convex part alternately. And H = 50 μm and L = 250 μm. Therefore, H / L = 0.5, which satisfies the relational expression of H / L ≦ 1.0.

(Example 2)
FIG. 13 is a diagram showing an example of a solar cell module formed in a concavo-convex shape on the entire bonding surface between the sealing material and the surface protection member. First, an uneven shape was formed on the entire surface of the surface protection member 15 using the above-described injection molding machine 20 and the mold cavity 21 (see FIG. 11). As the surface protection member 15, polycarbonate resin (Mitsubishi Engineering Co., Ltd., Iupilon S-2000, thickness 6 mm) was used.

  Next, the above-described laminating process (see FIG. 10) was performed using the surface protection member 15 having the uneven shape, and the solar cell module 11 was manufactured. At this time, the back surface protection member 16 was a rectangular sheet having a size of 1300 mm × 900 mm, and PVF (manufactured by DuPont, Tedlar (registered trademark) TTR10AH9, thickness 25 μm) was used as the material thereof.

  As the sealing material 14, an ethylene-vinyl acetate copolymer (manufactured by Mitsui Chemicals Fabro, SC-50B, thickness 1.2 mm) was used. A 125 mm square single crystal Si cell (thickness: 200 μm) was used as the power generation element 12, and a solder-plated rectangular wire (A-TPS, manufactured by Hitachi Cable Finetech Co., Ltd.) was used as the interconnector 13.

  As shown in FIG. 13, in the solar cell module 11, 48 power generating elements 12 are arranged in a grid of 8 rows and 6 columns. In the up-down direction and the left-right direction, the adjacent power generation elements 12 are aligned with an interval of 2 mm. The power generating elements 12 are arranged 143 mm inside from the end surface of the back surface protection member 16 in the vertical direction and 70 mm inside from the end surface of the back surface protection member 16 in the left and right direction.

  The adhesive surface between the sealing material 14 and the surface protection member 15 is formed in a smooth wave shape by alternately arranging a plurality of concave portions and convex portions in parallel. And H = 50 μm and L = 250 μm. Therefore, H / L = 0.5, which satisfies the relational expression of H / L ≦ 1.0.

  In addition, embodiment mentioned above shows an example of the solar cell module which concerns on this invention. The solar cell module according to the present invention is not limited to the one described in this embodiment. The solar cell module according to the present invention may be obtained by modifying the solar cell module according to the embodiment or applying it to others so as not to change the gist described in each claim.

It is a top view of the solar cell module concerning an embodiment. (A) is sectional drawing which follows the II line | wire of FIG. 1, (b) is sectional drawing which follows the II-II line | wire of FIG. It is the elements on larger scale of an uneven | corrugated area | region. It is a figure which shows the comparison with the sealing material for solar cell modules, and a common adhesive agent. It is a figure which shows the relationship between H / L and interface generation | occurrence | production stress. It is explanatory drawing which shows the effect of an uneven | corrugated area | region. It is a figure which shows the penetration | invasion state of resin to a saw-shaped adhesion surface. It is sectional drawing which shows the solar cell module formed in unevenness on the whole adhesive surface of a sealing material and a surface protection member. It is a figure which shows the method of forming uneven | corrugated shape in a surface protection member. It is a figure which shows a lamination process. It is a figure which shows the method of forming uneven | corrugated shape in a surface protection member. It is a figure which shows the Example of the solar cell module which concerns on embodiment. It is a figure which shows the Example of the solar cell module formed in uneven | corrugated shape in the adhesive surface whole surface of a sealing material and a surface protection member. It is a figure which shows the linear expansion coefficient of glass, an acrylic resin, and a polycarbonate. It is a figure which shows generation | occurrence | production of peeling. It is a figure which shows progress of peeling.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 ... Solar cell module, 2,12 ... Power generation element, 3A, 3B, 3C ... Cell strings, 4a, 4b, 4c ... Bypass diode, 6,14 ... Sealing material, 7,15 ... Surface protection member, 8 , 16... Back surface protection member, 10.

Claims (4)

A plurality of cell strings formed by connecting a plurality of power generating elements;
A sealing material for sealing the plurality of cell strings;
A surface protection member bonded to the light-receiving surface side of the sealing material;
A back surface protection member bonded to the back surface side of the sealing material;
With
The solar cell module according to claim 1, wherein a joint surface between the surface protection member and the sealing material is formed in an uneven shape between the cell strings.   The joint surface between the surface protection member and the sealing material is formed in a wave shape by alternately arranging convex portions and concave portions between the cell strings. The solar cell module according to.   ½ of the distance from the top of the convex portion adjacent in the height direction of the convex portion to the bottom of the concave portion is H, and the top of the convex portion adjacent in the juxtaposing direction of the convex portion and the concave portion The solar cell module according to claim 2, wherein a relational expression of H / L ≦ 1.0 is satisfied, where L is a half of a distance from the bottom of the recess to the bottom of the recess.   The solar cell module according to claim 1, wherein the plurality of cell strings are partitioned by a bypass diode.

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