JP2005317714A - Solar cell module and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a solar cell module which prevents the damages to solar cells when sealing the solar cells between warping plates by a resin. <P>SOLUTION: The present invention is the method of manufacturing the solar cell module which is such that a plurality of solar cells 4 are sealed by resin between a light receiving surface-side transparent plate 2 and a rear plate 3. Both the light receiving-side transparent plate 2 and the rear plate 3 have warping with a curvature radius of 500-10,000 mm. The plurality of solar cells 4 are arranged in order at a distance and are connected to each other by conductors 8. A first sealing resin sheet 20 is located between the light receiving surface-side transparent plate 2 and the solar cells 4, while a second sealing resin sheet 30 is located between the rear plate 3 and the solar cells 4. After arranging sealing resin sheet pieces 40, 41, 42, and 43 which are thicker than the solar cells 4 in the spaces 9 between the solar cells 4 or in a margin 10 outside the solar cells 4, the air between the light receiving surface-side transparent plate 2 and the rear plate 3 is exhausted, and then the resin is melted by heat treatment and cooled to seal the solar cells 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a solar cell module and a manufacturing method thereof. In particular, the present invention relates to a solar cell module in which solar cells are sealed with a resin between curved plates and a method for manufacturing the solar cell module.

  In recent years, awareness of environmental protection has increased, and solar power generation has become even more important. The solar battery cell is sandwiched between protective materials, sealed with a transparent resin, and used outdoors as a solar battery module. As a transparent resin for sealing, an ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA) resin or the like is used, which is sandwiched between a protective material and a solar battery cell. It is sealed by solidifying after heating and melting. In order to arrange and wire solar cells efficiently, it is preferable to seal a plurality of solar cells in one solar cell module.

  In addition, the installation location of solar cells has been diversified recently, and it has been used not only on the roof of buildings but also on the wall. When using it for a wall, not only it attaches to an outer wall, but the wall itself is also comprised with a solar cell module. In this case, since it has a great influence on the appearance of the building, it is important to make the solar cell modules regularly arranged without defects. At the same time, there is a demand for a large-area solar cell module having sufficient strength as a building structure.

  In the utility model registration No. 2500794 (patent document 1), in a laminate formed by joining two plate-like bodies via an adhesive sheet so as to sandwich a solar cell between the two adhesive sheets, A laminated body is described in which a sheet piece having a thickness substantially equal to that of the solar cell is sandwiched between gaps formed between the adhesive sheets outside the solar cell. By adopting such a configuration, the thickness of the peripheral portion of the laminated body can be made uniform, and moisture can hardly enter the gap from the outside, so that peeling can be prevented. In the examples of this publication, an example is described in which EVA is used as an adhesive sheet, and a plate glass having a curved end is used as a plate-like body.

  Japanese Patent Laid-Open No. 2003-110127 (Patent Document 2) discloses a solar cell module in which a plurality of solar cells are arranged between a front cover and a back cover and sealed with a transparent filler such as EVA. A solar cell module in which translucent spacers (setting blocks) are arranged between cells is described. As this spacer, it is described that it is optimal to use the same material as the transparent filler and the same thickness as the solar battery cell. It is said that this spacer can secure an air flow path without being deformed only by its own weight. Thus, it is described that a solar cell module having no air remaining therein can be manufactured.

  Japanese Unexamined Patent Publication No. 59-022978 (Patent Document 3) describes a filled adhesive sheet for a solar cell module containing an ethylene copolymer and an organic peroxide and having an embossed pattern on both sides thereof. Has been. The adhesive sheet has an embossed pattern, so that blocking of the sheet can be prevented, it is excellent in deaeration in the process of modularization, and it is said that bubbles are not easily generated. The embodiment of the publication describes a bonding method in which the temperature is raised to 150 ° C. while reducing the pressure in a vacuum laminator, the pressure is continuously reduced at 150 ° C. for 1 hour, and then the pressure reduction is stopped.

  In Japanese Patent Application Laid-Open No. 09-036405 (Patent Document 4), a photovoltaic element is formed between a front surface member and a back surface member through a sealing material resin, and the stacked body is a vacuum of 5 Torr or less. A solar cell module is described that is held for 5 to 40 minutes at a predetermined temperature, and then thermocompression-bonded at a vacuum degree of 5 Torr or less, and is cooled and bonded after the thermocompression bonding. It is said that a module that is less likely to cause peeling of the surface member and less likely to remain bubbles is provided by thermocompression bonding under such conditions. It is also described that the problem of remaining bubbles can be improved by inserting a non-woven fabric between the solar battery cell and the encapsulant resin and letting the air in the laminate escape through the voids in the non-woven fabric.

  In Japanese Patent Application Laid-Open No. 61-069179 (Patent Document 5), a solar panel laminated body in which solar cells are laminated between a cover glass and a back material through a filler is degassed by a double vacuum method. In addition, in the method for manufacturing a solar cell panel having a bonding step by pressurization after heating, there is a method for manufacturing a solar cell panel that uses EVA as a filler and holds the double vacuum chamber in a specific temperature range for a specific time. Has been described. By pasting together under specific temperature conditions, EVA can be completely crosslinked without foaming and yellowing. Under the conditions described in the examples, heating was started after the pressure was reduced to 0.3 Torr (about 0.0004 MPa), and when the temperature of the substrate surface on the heater side reached 140 ° C., vacuum pressing was performed and crosslinking was performed at 148 ° C. After the reaction, the vacuum pressure bonding is released after cooling to 50 ° C. or lower.

  However, when many cells are connected and sandwiched between two plates and sealed by thermocompression bonding, it is difficult to avoid damage to the solar cells. In particular, when the number of cells is large and the area of the entire module is large, a large load is likely to be applied unevenly, and it is inevitable that some cells that receive an excessive load are damaged. In a module, a number of cells are connected in series with each other, so that if a single cell breaks, a series of connected cells will not function. If the cell breaks, it not only impairs the appearance but also greatly reduces the power generation performance, so it must be discarded as a defective product. Therefore, a sealing method is desired in which cell damage is less likely to occur.

  In recent years, the use of bent glass on the outer walls of buildings has been increasing in response to the variety of designs required for buildings. Therefore, it is desired to encapsulate solar cells between curved substrates. However, since the solar battery cell is easily damaged, it is difficult to encapsulate it between the curved substrates.

  For example, Japanese Patent Laying-Open No. 2001-7376 (Patent Document 6) describes a solar cell module in which solar cells are sealed with a resin between curved glass plates. Here, a transparent acrylic resin anaerobic adhesive is used as the sealing resin, a spacer is arranged at the peripheral edge between the two substrates, and then the liquid adhesive is injected and cured. Yes. Thus, it was possible to enclose between the curved glass plates by curing the solar cells so that no load was applied. However, the operation of enclosing the liquid adhesive is not always easy, and it is difficult to arrange the plurality of solar cells. Moreover, satisfactory performance is not always obtained with respect to the adhesiveness and durability of the resin obtained by curing.

  Japanese Patent Laid-Open No. 9-92867 (Patent Document 7) discloses that a pre-formed sheet is formed by placing a filling sheet made of EVA resin on both sides of a solar battery cell in advance and heating the vacuum by bonding the layers. Thus, a method for manufacturing a solar cell module is described in which the preformed sheet is placed on a curved glass and bonded by vacuum heating. In the embodiment of the publication, when vacuum heating is performed, the preformed sheet and the curved glass are inserted into a rubber bag, set in a heating chamber, and heated while evacuating the rubber bag with a vacuum pump. A method is described. By adopting such a method, it is said that bonding to curved glass is also possible. However, the joining operation twice is complicated and cannot be applied to a configuration in which both surfaces are covered with curved glass.

  Therefore, even when encapsulating solar cells between curved substrates, the cells are not easily damaged, the sealing operation is easy, the solar cells can be arranged regularly, and adhesion and durability In addition, a sealing method capable of obtaining an excellent solar cell module is strongly desired.

Utility Model Registration No. 2500974 Japanese Patent Laid-Open No. 2003-110127 JP 59-022978 JP 09-034055 A Japanese Patent Laid-Open No. 61-069179 JP 2001-7376 A JP-A-9-92867

  The present invention has been made to solve such problems, and a solar battery module capable of preventing damage to solar cells when sealing the solar cells with a resin between curved plates. An object of the present invention is to provide a manufacturing method. It is another object of the present invention to provide a solar cell module in which solar cells are sealed with resin between curved plates.

  In the method for manufacturing a solar cell module in which a plurality of solar cells are sealed with resin between the light-receiving surface side transparent plate and the back surface plate, both of the light-receiving surface side transparent plate and the back surface plate have a curvature. A radius is 500-10000 mm, a plurality of solar cells are arranged at intervals and connected to each other by a conductive wire, and the light receiving surface side transparent plate is disposed between the light receiving surface side transparent plate and the solar cells. A first sealing resin sheet that covers substantially the entire surface is disposed, a second sealing resin sheet that covers substantially the entire surface of the back plate is disposed between the back plate and the solar battery cell, and between the solar cells. After the sealing resin sheet piece thicker than the thickness of the solar battery cell is disposed in the gap or the outer margin of the solar battery cell, the air between the light-receiving surface side transparent plate and the back plate is discharged and heated. The resin is melted and then cooled and sealed. It is solved by providing a module manufacturing method.

  When laminating the light-receiving surface side transparent plate and the back plate by disposing a sealing resin sheet piece that is thicker than the thickness of the solar battery cell in the gap between the solar battery cells or in the blank space outside the solar battery cell. Furthermore, the load from the front and back surfaces is not directly applied to the solar battery cell, and the sheet piece receives the load. And as the temperature rises, the resin softens and the thickness of the loaded sheet piece decreases, so that the cell or the portion of the conductive wire connected to the cell comes into contact with the upper and lower sealing resin sheets However, since the entire resin sheet is softened at that time, no local load is applied, and the cell or the conductive wire connected to the cell can be closely attached to be embedded in the softened sealing resin sheet. . As a result, cell cracking in the stacking process or the decompression process can be prevented. Since the light-receiving surface side transparent plate and the back plate are curved, a non-uniform load is likely to be applied to the cells, and it is particularly necessary to employ such a method.

  It is preferable that the sealing resin sheet piece is sandwiched between the first sealing resin sheet and the second sealing resin sheet. It is also preferable that the thickness of the sealing resin sheet piece is thicker than the total value of the thickness of the solar battery cell and the thickness of the conductive wire. It is also preferable that the thickness of the sealing resin sheet piece is 0.3 mm or more thicker than the thickness of the solar battery cell. It is also preferable that the thickness of the sealing resin sheet piece is 0.5 to 2 mm.

  In a preferred embodiment, when sealing in the sealing treatment container, the step of heating the sealing resin while maintaining the pressure in the sealing treatment container at 0.05 MPa or more (step 1), less than the melting point of the sealing resin A step of reducing the pressure in the sealing treatment container to a pressure of 0.01 MPa or less (step 2), a step of raising the temperature to a temperature equal to or higher than the melting point of the sealing resin with the pressure reduced (step 3), and the sealing treatment The sealing operation which consists of each process of the process of raising the pressure in a container (process 4) and the process of cooling (process 6) is performed. In another preferred embodiment, the sealing resin sheet is made of a crosslinkable thermoplastic resin and is sealed in the sealing treatment container at a temperature lower than the melting point of the sealing resin when sealing in the sealing treatment container. A step of reducing the pressure to 0.01 MPa or less (step 2), a step of raising the temperature to a temperature equal to or higher than the melting point of the sealing resin while reducing the pressure (step 3), and a step of raising the pressure in the sealing treatment vessel ( The sealing operation which consists of each process of the process (process 5) which heats up to the temperature range where a crosslinking reaction advances, the process (process 5) progresses, and the process (process 6) to cool is performed.

  Further, the above problem is a solar cell module in which a plurality of solar cells are sealed with a resin between a light receiving surface side transparent plate and a back surface plate, and both the light receiving surface side transparent plate and the back surface plate have a curvature. Provided is a solar cell module having a curvature with a radius of 500 to 10,000 mm, in which a plurality of solar cells are arranged at intervals and connected to each other with a conductive wire, and no spacer is provided on the periphery of the sealing resin layer It is also solved by doing. At this time, it is preferable that the number of the solar battery cells is 6 or more. It is also preferable that the solar battery cell is curved in the same direction as the light receiving surface side transparent plate and the back plate in the sealing resin layer. It is also preferable that the sealing resin layer has a thickness of 2 to 6 mm. It is also preferred that both the light-receiving side transparent plate and the back plate are bent glass. It is also preferable that the sealing resin is made of a kind of resin selected from the group consisting of ethylene-vinyl acetate copolymer, polyvinyl butyral, and polyurethane.

  According to the method for manufacturing a solar cell module of the present invention, the solar cell can be prevented from being damaged when the solar cell is sealed with a resin between curved plates.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an example of a solar cell module after a sealing operation. FIG. 2 is a schematic cross-sectional view of an example of a laminate before a sealing operation. FIG. 3 is an enlarged schematic cross-sectional view of the laminate before the start of the sealing operation in the example of FIG. FIG. 4 is an enlarged schematic cross-sectional view of the laminate in the middle of heating and heating in the example of FIG. FIG. 5 is an enlarged schematic cross-sectional view of the laminate after the sealing operation in the example of FIG.

  The cross-sectional schematic diagram of an example of the solar cell module 1 obtained by the manufacturing method of the present invention is shown in FIG. The solar cell module 1 is formed by sealing a plurality of solar cells 4 with a resin 5 between a light-receiving surface side transparent plate 2 and a back plate 3. Usually, the light receiving surface 6 and the back surface 7 of the adjacent solar battery cell 4 are connected via the conducting wire 8. The light-receiving surface side transparent plate 2 and the back plate 3 are curved in the same direction with substantially the same curvature. The solar battery cell 4 is also curved in the same direction as the light-receiving surface side transparent plate 2 and the back plate 3.

  As the solar battery cell 4 used in the present invention, various solar battery cells such as a single crystal silicon solar battery, a polycrystalline silicon solar battery, an amorphous silicon solar battery, and a compound semiconductor solar battery can be used. These solar cells 4 are generally thin plates having a thickness of 1 mm or less, more generally 0.5 mm or less, and are often quadrangular with sides of 5 cm or more. The substrate can be made of a semiconductor substrate such as silicon or germanium, a glass substrate, a metal substrate, etc. In the case of a silicon substrate, a thin plate is desired due to cost requirements, but it is a hard and brittle material. Therefore, it is particularly easily broken at the time of sealing, and the significance of adopting the production method of the present invention is great.

  A plurality of solar cells 4 are enclosed in one solar cell module 1. At this time, as the number of the solar battery cells 4 enclosed in one solar battery module 1 increases, the defective product rate resulting from the damage of the solar battery cell 4 increases, so that the practical advantage of adopting the manufacturing method of the present invention. Is big. Therefore, it is preferable that 6 or more, more preferably 12 or more, and even more preferably 20 or more solar cells 4 are arranged in one solar cell module 1.

  The width of the gap 9 between the adjacent solar cells 4 is not particularly limited, but is usually 0.5 mm or more, and in the case of less than this, the cells when the adjacent solar cells 4 come into contact with each other to be sealed May be damaged. If priority is given to daylighting, the gap 9 is preferably widened, and if priority is given to light utilization efficiency, the gap 9 is preferably narrowed. It is adjusted appropriately according to the usage and design requirements.

  The plurality of solar cells 4 are arranged with a predetermined width and are connected to each other by a conductive wire 8. At this time, the adjacent solar battery cells 4 are connected to each other by the conductive wire 8 between the light receiving surface 6 and the back surface 7, and a large number of solar battery cells 4 are connected in series. Connection between the light receiving surface 6 or the back surface 7 and the conductive wire 8 is performed using a conductive adhesive such as solder. Further, in order to efficiently collect the generated current, it is also preferable to form a current collection pattern with a conductive paste or the like on the light receiving surface 6 so as to be electrically connected to the conductor 8. Furthermore, there may be a case where non-adjacent cells or conductors 8 at a distant position are connected, or a hole is formed in the back plate 3 to lead the conductor 8 to the outside.

  The conductive wire 8 is also called an interconnector, but the material is not particularly limited, and a copper wire or the like is used. Since the light-receiving surface side transparent plate 2 and the back plate 3 are sandwiched and disposed, it is preferable to use a thin ribbon-shaped conductor 8, and the thickness is usually 0.5 mm or less, preferably 0.3 mm. It is as follows. Moreover, it is 0.05 mm or more normally. It is preferable that a conductive adhesive such as solder is applied to the conductive wire 8 in advance because the connection work becomes easy. In the state where the conductive wire 8 is connected, the height from the surface of the solar battery cell 4 to the highest portion of the conductive wire 8 varies depending on the location, but depending on the connection operation, the height is 0.5 mm than the thickness of the conductive wire 8. There are places where it gets thicker.

  In this invention, when connecting the conducting wire 8 to the photovoltaic cell 4, the photovoltaic cell 4 may bend. The reason for the curvature is not necessarily clear, but is considered to be due to the heat shrinkage of the paint applied to the back surface of the solar battery cell 4 or the difference in heat shrinkage between the solar battery cell 4 and the conductor 8. As described above, when the solar battery cell 4 is curved, the curved direction is preferably aligned with the curved direction of the light receiving surface side transparent plate 2 and the back plate 3. For example, it is preferable to seal the solar battery cell 4 with the convex surface side facing downward with the light-receiving surface side transparent plate 2 and the back surface plate 3 with the convex surface side facing downward. As described above, it is preferable that the directions of bending in the vertical direction are aligned, but it is more preferable that the directions of bending in the horizontal direction are aligned at the same time.

  The light-receiving surface side transparent plate 2 used in the present invention has a curvature with a radius of curvature of 500 to 10,000 mm. When the radius of curvature is less than 500 mm, it is difficult to seal while preventing cell cracking, and is preferably 700 mm or more. On the other hand, when the radius of curvature exceeds 10,000 mm, the difficulty of sealing using the curved light-receiving surface side transparent plate 2 is reduced, so that the necessity of employing the present invention is reduced. The curvature radius is preferably 5000 mm or less, and more preferably 2000 mm or less. Here, the shape of the light-receiving surface side transparent plate 2 may be a part of a cylinder or a part of a sphere. Further, the curvature may vary depending on the location and orientation, and in that case, the curvature radius referred to in the present invention refers to the minimum curvature radius in the region where the solar cells are present.

  The material of the light-receiving surface side transparent plate 2 should just be transparent with respect to sunlight, and polycarbonate resin, an acrylic resin, etc. can also be used besides glass. However, considering durability, hardness, flame retardancy, etc., it is preferable to use glass. Since a structural material having a large area is often formed, a glass plate having a surface compressive stress of 20 MPa or more is preferable from the viewpoint of strength. In addition, when the area is large, thermal cracking due to temperature rise due to sunshine or the like is likely to occur. From this point, it is preferable to use a glass plate having a surface compressive stress of 20 MPa or more. Furthermore, it is preferable to use a glass plate having a surface compressive stress of 20 MPa or more in order to prevent cracking due to a load applied locally during sealing.

  Here, the surface compressive stress of the plate glass is a value measured according to JIS R3222. Specific examples of the glass plate having a surface compressive stress of 20 MPa or more include double strength glass, tempered glass, and super tempered glass. Double-strength glass usually has a surface compressive stress of 20 to 60 MPa, tempered glass usually has a surface compressive stress of 90 to 130 MPa, and super-tempered glass usually has a surface compressive stress of 180 to 250 MPa. The strength increases as the surface compressive stress increases, but the manufacturing cost tends to increase. Double strength glass is preferable in that it does not fall as a fine piece when it is broken. The glass plate is selected according to the use and purpose.

  The radius of curvature of the back plate 3 is the same as that of the light receiving surface side transparent plate 2 and preferably has substantially the same radius of curvature as that of the light receiving surface side transparent plate 2. The back plate 3 does not necessarily have to be transparent, but if the lighting is taken into consideration, the back plate 3 should also be transparent to sunlight. Moreover, it is preferable to use a glass plate for the same reason as the light-receiving surface side transparent plate 2, especially a glass plate whose surface compressive stress is 20 MPa or more.

The material of the glass is not particularly limited, and soda lime glass is preferably used. In particular, for the light-receiving surface side transparent plate 2, highly transmissive glass (so-called white plate glass) is preferably used. High transmission glass is soda lime glass with a low iron content, and has high light transmittance. Further, as the glass of the back plate 3, in addition to using the high transmission glass and soda lime glass (so-called blue plate glass) having a relatively high iron content, heat ray reflecting glass, heat ray absorbing glass, etc. should be used. Is also preferred depending on the application. Moreover, the template glass etc. which formed the embossed pattern on the surface can also be used. Although the thickness of a glass plate is not specifically limited, If it uses as a structural material, it is preferable that it is 3 mm or more, and it is more preferable that it is 5 mm or more. Thus, when using a thick glass plate, the influence of its own weight is large, and there is a possibility that the cell may be damaged when the glass plate is stacked on the cell before bonding, and there is an actual advantage of adopting the manufacturing method of the present invention. large. The thickness of the glass plate is usually 20 mm or less. Moreover, although the area of glass is adjusted with a use, when it is 0.5 m < ² > or more, the actual profit which employ | adopts the manufacturing method of this invention is large.

  The material of the resin 5 is not particularly limited as long as it is transparent and has adhesiveness and flexibility, and is selected from the group consisting of ethylene-vinyl acetate copolymer (EVA), polyvinyl butyral, and polyurethane. One kind of resin is preferably used. At this time, a crosslinked resin is preferable from the viewpoint of strength and durability. Therefore, the raw material of the resin 5 is preferably a crosslinkable thermoplastic resin, particularly a resin that undergoes a crosslinking reaction when heated. Such a resin is sandwiched between the light-receiving surface side transparent plate 2 and the back plate 3 in the form of a sheet, heated and melted, then subjected to a crosslinking reaction as necessary, and then cooled and solidified to form a solar battery cell 4. Is sealed. By using a material that is crosslinked by heating, it can be made excellent in durability and adhesion. The crosslinkable thermoplastic resin is not particularly limited as long as it undergoes a crosslinking reaction when heated, but is a kind selected from the group consisting of ethylene-vinyl acetate copolymer (EVA), polyvinyl butyral, and polyurethane. Resins are preferably used. For example, EVA can be crosslinked by blending and heating a crosslinking agent, and polyurethane can be crosslinked by reacting an isocyanate group and a hydroxyl group.

  In the case of polyurethane, since the crosslinking reaction proceeds at a relatively low temperature, it is suitable when a resin plate having low heat resistance is used for at least one of the light receiving surface side transparent plate and the back plate. In addition, since polyurethane is also excellent in flexibility, it is suitable for use when it is used for the light-receiving surface side transparent plate and the back plate in combination with materials with greatly different coefficients of thermal expansion such as glass and plastic. It is. Furthermore, polyurethane has excellent penetration strength.

  Among the crosslinkable thermoplastic resins, it is preferable to use a thermoplastic resin containing a crosslinking agent. The thermoplastic resin at this time is not particularly limited as long as the crosslinking reaction proceeds when heated together with the crosslinking agent, but an ethylene-vinyl acetate copolymer (EVA) excellent in transparency, flexibility, durability and the like. Is most preferably used.

  The sealing resin sheet is sandwiched between the light-receiving surface side transparent plate 2 and the back plate 3, melted by heating, and then cooled and solidified to seal the solar cells 4. It is preferable that the sealing resin sheet contains a crosslinking agent in EVA resin. In this case, the resin is heated and melted and then a crosslinking reaction is allowed to proceed, followed by cooling to seal with the crosslinked EVA. Can do. The EVA in the sealing resin sheet preferably has a melting point of 50 to 80 ° C. measured by the DSC method from the viewpoint of the balance between transparency and form retention.

  It is preferable that the sealing resin sheet has an appropriate embossed surface on one or both sides because blocking can be prevented and remaining bubbles are easily suppressed. A suitable embossing depth is 10 to 100 μm, and if it is too deep, there is a possibility that bubbles remain. The sheet thickness is preferably 0.2 to 2 mm, and more preferably 0.3 to 1 mm, and one or a plurality of the sheets can be stacked to adjust the thickness.

  Hereinafter, the sealing operation method according to the manufacturing method of the present invention will be described with reference to FIG. First, the 1st sealing resin sheet 20 is accumulated on the light-receiving surface side transparent plate 2 so that the whole surface may be covered substantially. In the example of FIG. 2, the operation of overlapping is performed after placing the light-receiving surface side transparent plate 2 on the lower side, but it may be performed in the reverse order after the back surface plate 3 is first placed on the lower side. At this time, from the viewpoint of workability, it is preferable to dispose the light-receiving surface side transparent plate 2 or the back plate 3 so that the concave surface side is on, and to overlap the sealing resin sheet thereon.

  The thickness of the first sealing resin sheet 20 is preferably 0.5 mm or more, and more preferably 1 mm or more. Also, it is usually 5 mm or less, preferably 3 mm or less. By setting the thickness to a certain value or more, the solar battery cell 4 can be effectively protected. The first sealing resin sheet 20 is preferably configured by laminating a plurality of sealing resin sheets. This is because it becomes easy to adjust the thickness of the first sealing resin sheet 20 according to the application and required performance. In the example of FIG. 2, the first sealing resin sheet 20 is configured by stacking three sealing resin sheets 21, 22, and 23. The first sealing resin sheet 20 only needs to cover substantially the entire surface of the light-receiving surface-side transparent plate 2, and a part of the first sealing resin sheet 20 may be missing due to the arrangement of the conductive wires. You may be comprised from the several sealing resin sheet arrange | positioned.

  On the 1st sealing resin sheet 20, the photovoltaic cell 4 is mounted. At this time, a plurality of solar cells 4 connected to each other in the manner described above are placed, and arranged vertically and horizontally as necessary. In this case, the solar cells 4 that are connected in advance may be placed, may be connected on the first sealing resin sheet 20, or after the part that has been partially connected is placed, You may connect. In the example of FIG. 2, the solar cells 4 that are connected to each other by the conductive wires 8 and are curved so that the light receiving surface 6 is on the convex surface side are arranged with the light receiving surface 6 facing down.

  Subsequently, in the blank portion 10 outside the solar battery cell 4, on the first sealing resin sheet 20, a sealing resin sheet piece 40 disposed substantially continuously over the entire circumference of the blank portion 10, and The sealing resin sheet piece 41 which is overlapped with it and arranged at intervals is arranged. Further, sealing resin sheet pieces 42 and 43 are arranged in the gap 9 between the solar battery cells 4.

  The sealing resin sheet pieces 40 and 41 or the sealing resin sheet pieces 42 whose total thickness is larger than the thickness of the solar battery cells 4 in the blank space 10 outside the solar battery cells 4 or in the gaps 9 between the solar battery cells 4. , 43, when the inside is decompressed, a load due to atmospheric pressure from both the front and back surfaces is not directly applied to the solar battery cell 4, and the sealing resin sheet pieces 40, 41 or the sealing resin sheet piece 42 are provided. 43 receive the load. Therefore, it is possible to prevent the load on the back plate 3 from being directly applied to the solar cells 4 arranged in the module, and it is possible to prevent cell cracking in the decompression step. In particular, as the number of solar cells 4 enclosed in one solar cell module 1 increases, the defective product rate resulting from the damage of the solar cells 4 increases. Therefore, the sealing resin sheet pieces 40, 41, The actual benefit of arranging 42 and 43 is great. Here, the total thickness means the total thickness of the overlapping portions when a plurality of sealing resin sheet pieces are used in an overlapping manner.

  The total thickness of the sealing resin sheet pieces is preferably thicker than the total value of the thickness of the solar battery cell 4 and the thickness of the conductive wire 8, and more preferably 0.2 mm or more thicker than the total value. Moreover, it is preferable that the total thickness of the sealing resin sheet piece is 0.3 mm or more thicker than the thickness of the solar battery cell 4, and more preferably 0.6 mm or more. Specifically, it is preferable that the total thickness of the sealing resin sheet pieces is 0.5 to 5 mm. The total thickness of the sealing resin sheet pieces is more preferably 0.8 mm or more, and even more preferably 1 mm or more. If the thickness is too thin, cell cracks may occur during the sealing operation. On the other hand, the total thickness of the sealing resin sheet pieces is more preferably 3 mm or less. If the thickness is too thick, bubbles are likely to remain when sealed between the curved light-receiving surface side transparent plate 2 and the back plate 3. In order to highly suppress the generation of bubbles, the thickness is more preferably 2 mm or less, and most preferably 1.5 mm or less. For example, even if the solar battery cell 4 made of a silicon substrate has a certain degree of flexibility, cell cracking often does not occur even if the total thickness of the sealing resin sheet pieces is relatively thin. . Therefore, it is preferable that the total thickness of the sealing resin sheet pieces is thinner or the same as the thickness of the first sealing resin sheet 20 or the second sealing resin sheet 30.

  It is preferable that the sealing resin sheet pieces 40, 41, 42 and 43 are arranged at intervals in the horizontal direction so that the internal air can be discharged therefrom. By securing a passage for positively discharging the internal air, it is possible to suppress the remaining of bubbles, and it is possible to manufacture the solar cell module 1 having a good appearance. At this time, in the case where the sealing resin sheet pieces are directly stacked, it is sufficient that at least one of the sealing resin sheet pieces has a horizontal space between the resin sheet pieces and the internal air can be discharged therefrom. .

  In the example of FIG. 2, the sealing resin sheet piece disposed substantially continuously over the entire periphery of the blank portion 10 on the first sealing resin sheet 20 in the blank portion 10 outside the solar battery cell 4. 40 and a sealing resin sheet piece 41 which is overlapped with each other and arranged with a space therebetween are disposed, and the second sealing resin sheet 30 is superimposed thereon. By disposing the sealing resin sheet pieces 40 continuously at the same height as the solar cells 4 over the entire circumference, it is possible to uniformly fill the molten resin and prevent the generation of bubbles. The sealing resin sheet piece 40 preferably has a width of 50% or more of the blank portion 10 and more preferably has a width of 70% or more. The sealing resin sheet piece 40 may be composed of a plurality of sheet pieces arranged in parallel. It is preferable that the sealing resin sheet piece 41 is disposed on the sealing resin sheet piece 40 so as to be spaced apart from each other, whereby the internal air can be discharged smoothly.

  In the example of FIG. 2, the sealing resin sheet pieces 42 and 43 are disposed on the first sealing resin sheet 20 in the gap 9 between the solar cells 4. Here, two sealing resin sheet pieces are stacked and arranged. By disposing the sealing resin sheet pieces 42 and 43 in the gap portion 9 between the solar battery cells 4, the load due to atmospheric pressure from both the front and back surfaces is not directly applied to the solar battery cell 4 when the inside is decompressed. The sealing resin sheet pieces 42 and 43 receive the load. And as the temperature rises, the resin softens and the thickness of the encapsulating resin sheet pieces 42 and 43 applied with a load decreases, so that the solar cells 4 or the conductive wires 8 are connected to the first encapsulating resin sheet 20 and It contacts the second sealing resin sheet 30. At that time, since the entire resin sheet is softened, no local load is applied, and the solar battery cells 4 or the conductive wires 8 are in close contact with each other so as to be embedded in the softened sealing resin sheet. Thereby, cell cracking in the decompression step can be prevented. The situation at this time is schematically shown in FIGS. In FIGS. 3 to 5, for simplicity, the curve is omitted and shown as a straight line. That is, FIG. 3 is an enlarged schematic cross-sectional view of the laminate before the start of the sealing operation, FIG. 4 is an enlarged schematic cross-sectional view of the laminate in the middle of heating and heating, and FIG. It is an expanded sectional schematic diagram. In this case, since it is possible to reliably receive loads from above and below in the vicinity of the individual solar battery cells 4, cell cracking can be effectively prevented.

  It is preferable that the width of the sealing resin sheet pieces 42 and 43 disposed in the gap portion 9 is narrower than the width of the gap portion 9. By doing so, it becomes easy for the sealing resin sheet pieces 42 and 43 thicker than the solar battery cell 4 to spread over the entire gap portion 9 with a constant thickness. When the molten resin moves over a wide range, the solar battery cell 4 may move accordingly. The width is adjusted in consideration of the thickness of the solar battery cell 4 and the sealing resin sheet pieces 42 and 43, the area of the gap 9 and the like, but preferably 0.1 to 0.95 of the width of the gap 9. Is double. More preferably, it is 0.3 times or more and 0.9 times or less. If it exceeds 0.95 times, it is difficult to arrange it, and the solar battery cell 4 or the conductive wire 8 may be damaged during decompression. On the other hand, when the ratio is 0.1 times or less, the molten resin may be difficult to spread uniformly. The lengths of the sealing resin sheet pieces 42 and 43 are not particularly limited, and may be shorter than one side of the solar battery cell 4, and may be a tape-like one extending from one end of the solar battery module to the other end. It does not matter.

  Moreover, it is also preferable that the internal air can be discharged from between the sealing resin sheet pieces arranged in the gap portion 9. By securing a passage for positively discharging the internal air, it is possible to suppress the remaining of bubbles, and it is possible to manufacture a solar cell module with a good appearance. At this time, when the sealing resin sheet piece has a structure in which a plurality of sealing resin sheets are laminated, at least one of the sealing resin sheet pieces is spaced from each other, and the internal air is discharged therefrom. I can do it. In the case where the sealing resin sheet pieces are arranged so as to intersect with each other, the internal air can be discharged from a place where the total thickness other than the intersecting portion is thin.

  Thus, in order to effectively prevent cell cracking, it is preferable to arrange the sealing resin sheet pieces 42 and 43 in the gap 9 between the solar battery cells 4. In general, such a configuration is suitable when the width of the gap 9 is preferably 5 mm or more, more preferably 10 mm or more, and even more preferably 20 mm or more. When the width of the gap portion 9 is narrow, it is difficult to dispose the sealing resin sheet pieces 42 and 43, so that the sealing resin sheet piece is disposed only in the blank portion 10 outside the solar battery cell 4. Is good. Such a configuration is suitable when the width of the gap 9 is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less.

  Thus, after mounting the sealing resin sheet pieces 40, 41, 42, 43, the second sealing resin sheet 30 is mounted thereon. A suitable configuration and a suitable thickness of the second sealing resin sheet 30 are the same as those of the first sealing resin sheet 20. In the example of FIG. 2, the second sealing resin sheet 30 is configured by overlapping three sealing resin sheets 31, 32, and 33. Finally, the back plate 3 is placed on the second sealing resin sheet 30. At this time, the back surface plate 3 preferably has a curvature with substantially the same radius of curvature as the light receiving surface side transparent plate 2, and the convex surface side is directed downward.

  In the above, the structure of the laminated body 60 before sealing operation was demonstrated. Subsequently, the air between the light-receiving surface side transparent plate 2 and the back plate 3 is discharged, heated to melt the resin, and then cooled and sealed. At this time, it is preferable to heat and melt the resin to advance the crosslinking reaction and then cool and seal.

  The apparatus used for sealing is not particularly limited as long as it can perform an air discharging operation and a heating operation. It is preferable to use a container having a sealing treatment container that accommodates the laminated body 60 and capable of discharging air and heating. At this time, it is preferable that a part or all of the sealing treatment container is made of a gas non-permeable flexible film. The material of the membrane may be a flexible membrane that is impermeable to gas, has a certain degree of flexibility and strength, and when the inside of the membrane is evacuated, the external pressure is uniformly applied to the entire laminate. If it becomes, it will not specifically limit, The sheet | seat and film of rubber | gum and resin can be used. It is preferable to use a bag 61 made of a flexible film that is entirely gas impermeable. In this case, since the sealing treatment container is simply the bag 61, it is possible to flexibly cope with the production of solar cell modules having various shapes and dimensions, and products having various dimensions such as building materials can be used. It is particularly suitable for applications that require manufacturing. In particular, in the manufacturing method of the present invention, since the solar cells 4 are enclosed between curved plates, the whole is preferably a flexible bag in order to prevent the plates from being damaged during the sealing process. When the laminated body 60 is introduced into the bag 61, the entire circumference of the end surface of the laminated body 60 is covered with a bleeder 62 made of a breathable material to prevent the molten resin inside the laminated body 60 from flowing out, It is preferable to secure a discharge route for air from inside the laminate 60. As a material used for the bleeder 62, fabrics such as a woven fabric, a knitted fabric, and a non-woven fabric can be used.

  Thus, when using the bag 61 which consists of a flexible film | membrane with a gas impermeable whole, multiple bags 61 in which the laminated body 60 was introduce | transduced can be arrange | positioned in a heating apparatus. Each bag 61 is connected to a pipe 63 that can be evacuated and connected to a vacuum pump 65 via a pressure regulating valve 64. By such a method, a plurality of pasting operations can be performed together with a simple apparatus.

  When arranged as described above, the air between the light receiving surface side transparent plate 2 and the back plate 3 is discharged, heated to melt the resin, and then cooled and sealed. The temperature condition at this time is not particularly limited, and may be increased to a temperature at which the resin can be melted. If the resin is a crystalline resin, it may be heated to the melting point of the resin or higher. Further, if the sealing resin is a crosslinkable thermoplastic resin, the sealing resin is raised to a crosslinkable temperature and maintained at a crosslinkable temperature for a predetermined time. The pressure is not particularly limited as long as the pressure in the stacked body 60 can be reduced to a pressure at which air remaining in the laminate 60 can be discharged and the remaining bubbles can be reduced.

  In particular, when sealing in the sealing treatment container, the step of heating the sealing resin while maintaining the pressure in the sealing treatment container at 0.05 MPa or more (step 1), at a temperature below the melting point of the sealing resin A step of reducing the pressure inside the sealing treatment container to a pressure of 0.01 MPa or less (step 2), a step of raising the temperature to a temperature equal to or higher than the melting point of the sealing resin while keeping the pressure reduced (step 3), It is preferable to perform a sealing operation including the steps of increasing the pressure (step 4) and cooling (step 6).

  The step 1 is a step of heating the sealing resin while maintaining the pressure in the sealing treatment container at 0.05 MPa or more. By maintaining the pressure in the sealing treatment container at 0.05 MPa or more, it is possible to prevent a large load from being applied to the cell from the vertical direction of the laminate 60. More preferably, the pressure is 0.06 MPa or more. A process for preventing cell cracking when the sealing resin sheet piece is disposed only in the blank portion 10 outside the solar battery cell 4 and the sealing resin sheet fragment is not disposed in the gap 9 between the solar battery cells 4. 1 is preferably employed. Moreover, when the light-receiving surface side transparent plate 2 or the back surface plate 3 is a non-strengthened bent glass, it is preferable to employ the step 1 in order to prevent breakage of the plate. When strengthening is performed and a sealing resin sheet piece is disposed in the gap 9 between the solar cells 4, it is preferable to omit the step 1 from the viewpoint of production efficiency.

  Although the pressure in the sealing process container in step 1 may be atmospheric pressure (0.1 MPa), leakage of the sealing process container can be checked by reducing the pressure to, for example, 0.09 MPa or less. In step 1, since the sealing resin is not yet melted, if there is a leak in the sealing processing container, it can be repaired at this stage. In particular, when a flexible bag is used as the sealing container, it is preferable to reduce the pressure slightly as described above because the bag is easily damaged. When the pressure is reduced from atmospheric pressure to a predetermined pressure of 0.05 MPa or more, it is preferable that the time required for the pressure reducing operation is 10 minutes or more. This is because although a large load is not applied, a rapid decompression operation may cause cell cracking.

  As described above, the sealing resin is softened in advance by heating the sealing resin in a state where the pressure in the sealing processing container is high. The temperature reached by heating at this time is a temperature at which the elastic modulus is lowered while the sealing resin is not melted. Here, the temperature at which the sealing resin does not melt is usually a temperature lower than the melting point (Tm), preferably (Tm-5) ° C. or less, and more preferably (Tm-10). It is below ℃. When the sealing resin does not have a melting point, the melting point referred to here may be replaced with a glass transition point or a softening point. In many sealing resins, a suitable temperature is 65 ° C. or lower, and a more preferable temperature is 60 ° C. or lower. If the temperature is too high, the flow of the resin starts before the pressure in the sealing treatment container drops to 0.01 MPa or less in Step 2, and the passage for discharging the air inside the laminate 60 is blocked. There is a risk that bubbles will be removed and bubbles will remain. The temperature reached by the heating is preferably (Tm-30) ° C. or higher, and more preferably (Tm-20) ° C. or higher. In many sealing resins, a suitable temperature is 40 ° C. or higher, and a more preferable temperature is 45 ° C. or higher. When the said temperature is too low, the fall of the elasticity modulus of sealing resin is inadequate, and when the pressure in a sealing process container is reduced in process 2, there exists a possibility that a cell crack may generate | occur | produce. It is preferable to start the pressure reduction operation in Step 2 after maintaining the temperature in such a temperature range for 5 minutes or more.

  Step 2 is a step of depressurizing the inside of the sealing treatment container to a pressure of 0.01 MPa or less at a temperature lower than the melting point of the sealing resin, and when Step 1 is employed, a step performed subsequent to Step 1 It is. By reducing the pressure at a temperature lower than the melting point of the sealing resin, a passage through which the air inside the laminate 60 is discharged is secured. At this time, the pressure in the sealing treatment container is preferably reduced to 0.005 MPa or less. By sufficiently reducing the pressure, the remaining bubbles after sealing can be effectively suppressed. It is preferable that the temperature during pressure reduction from 0.05 MPa to 0.01 MPa in Step 2 is maintained in the same temperature range as the temperature reached by the heating described in Step 1. Further, in order to prevent cell cracking due to an abrupt depressurization operation, it is preferable to slowly depressurize from 0.05 MPa to 0.01 MPa over 5 minutes or more.

  Step 3 is a step of raising the temperature to a temperature equal to or higher than the melting point of the sealing resin while reducing the pressure, and is a step performed subsequent to Step 2. When the temperature of the encapsulating resin is raised, the elastic modulus is greatly lowered near the melting point and changes to a highly viscous liquid. Step 3 is a step in which the pressure is kept reduced until such temperature is reached. If the pressure is increased by lowering the degree of decompression while the elastic modulus is high, air flows into the laminated body 60, and bubbles may remain in the sealing resin. Here, the lower limit value of the temperature reached by the temperature raising operation in Step 3 is preferably (Tm + 10) ° C. or more, and more preferably (Tm + 20) ° C. or more. In many sealing resins, a suitable lower limit is 80 ° C. or higher, and more preferably 85 ° C. or higher. Moreover, an upper limit is 200 degrees C or less normally.

  The rate of temperature increase in step 3 is preferably slow, the time taken to increase the temperature from room temperature to the above temperature is preferably 15 minutes or more, more preferably 30 minutes or more, and more preferably 1 hour or more More preferably. By slowly raising the temperature, a sudden load is not applied and cell cracking can be efficiently prevented. At this time, the temperature increase rate may be changed in the middle, or a balancing operation may be performed to stop the temperature increase and eliminate the temperature distribution inside the laminate 60. From the viewpoint of productivity, the temperature raising time is usually 20 hours or less.

  Step 4 is a step of increasing the pressure in the sealing treatment container, and step 6 is a step of cooling, both of which are performed subsequent to step 3. Either step 4 or step 6 may be performed first, or both steps may be performed simultaneously. In the cooling step of Step 6, the glass is usually cooled to around room temperature. However, if the cooling rate is too fast, the glass may break, and thus cooling is preferably performed for 10 minutes or more, and more preferably for 30 minutes or more.

  In step 4, the pressure is preferably increased slowly, and the time for the pressure increase is preferably 5 minutes or more, more preferably 10 minutes or more, and further preferably 20 minutes or more. From the viewpoint of productivity, the pressurization time is usually 5 hours or less, and preferably 2 hours or less. The pressure after the pressure increase is preferably 0.05 MPa or more, more preferably 0.07 MPa or more, and the pressure can be increased to the same pressure (0.1 MPa) as the atmospheric pressure. At this time, the voltage may be increased stepwise. In step 4, when the temperature at which the pressure is increased is too high, the molten resin may flow unnecessarily, and the cell may move. It is usually 120 ° C. or lower, preferably 100 ° C. or lower.

  In step 4, it is preferable to have a process of simultaneously raising the temperature while increasing the pressure in the sealing treatment container. In this way, in the process of gradually increasing the fluidity, the pressure applied to the laminate 60 can be gradually released, and the molten resin flows unnecessarily while suppressing the generation of residual bubbles. It is effective to suppress. In this case, the temperature at the start of boosting is (Tm-10) ° C. to (Tm + 20) ° C., more preferably (Tm−5) ° C. to (Tm + 15) ° C., and then 3 to 30 ° C., more preferably It is desirable to increase the pressure while raising the temperature from 5 to 20 ° C. The ratio of the pressure increase rate (MPa / min) to the temperature increase rate (° C / min) is preferably 0.001 to 0.1 (MPa / ° C), 0.002 to 0.05 (MPa / ° C). It is more preferable that

  When a crosslinkable thermoplastic resin is used as the sealing resin, after the step of raising the temperature to near the melting point of the sealing resin while reducing the pressure (step 3), the pressure in the sealing treatment container is increased. It is preferable to have a step of raising the temperature to a temperature range where the crosslinking reaction proceeds (step 5) through a step of raising (step 4) (step 5) and a step of cooling (step 6).

  In this case, it is also preferable to raise the pressure in the sealing treatment container in Step 4 and then cool it to a temperature below the melting point and then raise the temperature to a temperature range in which the crosslinking reaction proceeds in Step 5. After raising the pressure, it is possible to raise the temperature to the temperature range where the crosslinking reaction proceeds as it is, but by cooling it once, it is possible to secure a time for the residual stress to relax, and the melted resin can overflow and sink. (The portion where the resin is missing at the end), the movement of the cell can be more effectively suppressed. At this time, it is preferable to cool until the resin sufficiently loses fluidity, and it is preferable to cool to (Tm-10) ° C. or lower, more preferably to (Tm-20) ° C. or lower.

  As described above, after increasing the pressure in the sealing treatment container, the temperature is raised to a temperature range where the crosslinking reaction proceeds in Step 5 to advance the crosslinking reaction. Usually, the crosslinking reaction proceeds by heating to 100 ° C or higher, preferably 120 ° C or higher, more preferably 130 ° C or higher, and even more preferably 140 ° C or higher. In order to prevent deterioration of the resin, a crosslinking temperature of 200 ° C. or lower is usually employed. The time for maintaining the temperature range in which the crosslinking reaction proceeds varies depending on the desired degree of crosslinking and the like, but is usually 5 minutes to 2 hours, preferably 10 minutes to 1 hour.

  The pressure in the sealing treatment container when the crosslinking reaction is advanced in step 5 is preferably 0.05 MPa or more, and more preferably 0.06 MPa or more. By increasing the pressure in the sealing processing container, the pressure applied from above and below can be reduced. Since the crosslinking reaction proceeds at a high temperature, the melt viscosity of the sealing resin at that time is considerably lower than the vicinity of the melting point. Therefore, at this time, it is important not to apply unnecessary pressure from above and below, but to suppress the movement of the cell and the protrusion of the resin. However, when the pressure is increased to the same pressure as the atmospheric pressure, sinking may occur depending on the configuration of the laminated body. In such a case, it is preferable to set the pressure lower than the atmospheric pressure. In addition, if the pressure is increased to the same pressure as the atmospheric pressure, the bleeder may be difficult to press around the laminate and the resin may protrude, so in such a case, the pressure should be set lower than the atmospheric pressure. Is preferred. In that case, the pressure is preferably 0.001 MPa or more lower than atmospheric pressure, and preferably 0.01 MPa or more (in this case, 0.09 MPa or less). The atmospheric pressure as used in the present invention refers to a state in which no positive pressure or depressurization operation is performed. For example, hot air is forcibly blown into the hot air furnace by a fan, so that the atmospheric pressure is slightly higher than atmospheric pressure. Even in such a case, it is substantially the same as the atmospheric pressure.

  After the crosslinking reaction has proceeded in step 5, it is subjected to the cooling step in step 6. The cooling process 6 is as described above.

  The solar cell module obtained in this way is filled with sealing resin up to the peripheral edge of the module, and does not have a spacer on the peripheral edge of the sealing resin layer. Since it can seal to a peripheral part with sealing resin excellent in adhesiveness and durability, a highly reliable solar cell module can be provided. The total thickness of the sealing resin layer is preferably 2 to 6 mm. More preferably, it is 3 mm or more and 5 mm or less. In the sealing resin layer, there are usually solar cells that are curved in the same direction. It is not only whether the solar cell to be subjected to the sealing operation is curved in advance, but is often curved according to the curvature of the light-receiving surface side transparent plate and the back plate, so that the appearance is also beautiful. .

  The solar cell module of the present invention is a regularly aligned array without a plurality of solar cells being damaged between the curved substrates. Since a large number of solar battery cells can be sealed with resin without being damaged, a large-sized solar battery module can be provided. In addition, the remaining of bubbles is suppressed, the protrusion of the resin from the end portion is also suppressed, and the resin is properly aligned and has a beautiful appearance. Therefore, it is suitably used for the outer walls, roofs, windows, etc. of various buildings.

  Hereinafter, the present invention will be described in more detail using examples.

  As the solar battery cell 4, 24 square polycrystalline silicon solar battery cells of 125 mm × 125 mm × 0.35 mm were used. The four corners are chamfered about several mm. As the conducting wire 8, a solder dip copper ribbon wire manufactured by Hitachi Cable, Ltd. was used. The ribbon wire has a width of 1.5 mm and a thickness of 0.25 mm. Solder is printed in advance on a portion where the light receiving surface 6 of the solar battery cell 4 and the conductive wire 8 on the back surface 7 are bonded. One end of the conductor 8 was overlapped and soldered to the solder printing portion of the light receiving surface 6 of the solar battery cell 4, and the other end was overlapped and soldered to the solder printing portion of the back surface 7 of the adjacent solar battery cell 4. Adjacent cells were connected by two conducting wires 8 so that the distance between them was 50 mm. That is, the width of the gap 9 is 50 mm. In soldering, the solar battery cell 4 was placed on a hot plate with the light receiving surface 6 facing upward, the conductor 8 was soldered to the light receiving surface 6 while heating, and then allowed to cool on the glass plate. As a result, the light receiving surface 6 was bent in a direction toward the convex surface side. Thereafter, the conductor 8 was soldered to the back surface 7 with a soldering iron, but the curvature was maintained. The solar cells 4 to which the conductive wires 8 were connected in this way were bent about 2 to 3 mm perpendicular to the series direction so that the light receiving surface 6 was on the convex side.

  As the light-receiving surface side transparent plate 2, tempered bent glass (white plate glass) of 1200 mm × 800 mm × 5 mm was used. The shape of the tempered bent glass consists of a part of a cylinder, and its short side is curved. The curvature radius of the curve is 1000 mm, and the short side length of 800 mm is the length as a curve. The tempered bent glass has a surface compressive stress of 100 MPa. As the sealing resin sheet, unless otherwise specified, a 0.6 mm thick sheet of “Solar Eva SC36” manufactured by Hisheet Kogyo Co., Ltd. was used. The sealing resin sheet is obtained by blending an ethylene-vinyl acetate copolymer (EVA) with a crosslinking agent, a silane coupling agent, a stabilizer and the like, and the melting point measured by the DSC method of the resin before crosslinking is 71 ° C. It is. A shallow embossed pattern (pear texture) is formed on one side of the sealing resin sheet, and the depth is about 45 μm. Three sealing resin sheets 21, 22, and 23 having a size of 1200 mm × 800 mm were stacked thereon such that the concave surface of the light-receiving surface side transparent plate 2 was on top. The three sealing resin sheets 21, 22, and 23 constitute a first sealing resin sheet 20 having a thickness of 1.8 mm.

  As shown in FIG. 6, six sets of four solar cells 4 connected in series in the short side direction are arranged in parallel at intervals of 50 mm, and a total of 24 cells are arranged on the first sealing resin sheet 20. Arranged. The width of the gap 9 between the adjacent solar battery cells 4 is 50 mm both vertically and horizontally. In the edge part of the photovoltaic cell 4 arrange | positioned in series, the conducting wires 8 connected to the photovoltaic cell 4 were connected with the conducting wire 51 of the position 5 mm away. The distance from the end of the solar battery cell 4 to the end of the light-receiving surface side transparent plate 2, that is, the width of the margin 10, was 100 mm at the left and right ends in FIG. As the conducting wire 51, a solder dip copper ribbon wire having a width of 4.0 mm and a thickness of 0.25 mm was used.

  Subsequently, as illustrated in FIG. 7, the sealing resin sheet piece 44 is disposed in the blank portion 10. The sealing resin sheet piece 44 was disposed along the end of the light-receiving surface side transparent plate 2 over the entire circumference of the blank portion 10. In the left and right margins 10 (width is 100 mm), the width of the sealing resin sheet piece 44 is 80 mm, and in the upper and lower margins 10 (width is 75 mm), the width of the sealing resin sheet piece 40 is 60 mm. Next, as shown in FIG. 8, three sealing resin sheet pieces 45 having a width of 45 mm and a length of 1200 mm were placed in parallel in the gap 9 between the solar cells 4. The sealing resin sheet piece 45 overlaps the sealing resin sheet piece 44 at both ends, and a part thereof overlaps the conductive wire 8. Next, five sealing resin sheet pieces 46 having a width of 45 mm and a length of 800 mm were placed in parallel in the gap 9 between the solar cells 4. The sealing resin sheet piece 46 overlaps the sealing resin sheet piece 44 at both ends, and a part thereof overlaps the sealing resin sheet piece 45 and the conductive wire 51.

  Subsequently, as shown in FIG. 9, 38 sealing resin sheet pieces 47 of 40 mm × 100 mm were arranged on the sealing resin sheet pieces 45 and 46 in the gap 9 between the adjacent solar cells 4. Further, four 50 mm × 50 mm sealing resin sheet pieces 48 were arranged on the sealing resin sheet pieces 44 at the four corners of the module. In FIG. 10, the thickness of the sealing resin sheet piece is 1.2 mm in total in the portion indicated by hatching, and the thickness of the sealing resin sheet piece in the other portion is 0.6 mm. By setting it as such a structure, a clearance gap can be provided between the sealing resin sheet 31 and the sealing resin sheet piece 44 which are laminated | stacked continuously, and between the sealing resin sheet 23 and the sealing resin sheet 31 can be provided. The air in the formed space can be discharged smoothly. Subsequently, three sealing resin sheets 31, 32, and 33 having a size of 1200 mm × 800 mm were stacked thereon. The three sealing resin sheets 31, 32, 33 constitute a second sealing resin sheet 30 having a thickness of 1.8 mm.

  Finally, the back plate 3 was stacked with its concave side facing downward. As the back plate 3, tempered bent glass (blue plate glass) of 1200 mm × 800 mm × 5 mm was used. The shape of the tempered bent glass consists of a part of a cylinder, and its short side is curved. The curvature radius of the curve is 1000 mm, and the short side length of 800 mm is the length as a curve. The tempered bent glass has a surface compressive stress of 100 MPa.

  As described above, a laminate 60 for use in the sealing operation was obtained. Here, the 1st sealing resin sheet 20 consists of three sealing resin sheets, and the total thickness is 1.8 mm. Moreover, the 2nd sealing resin sheet 30 also consists of three sealing resin sheets, and the total thickness is 1.8 mm. Moreover, the total thickness of the overlapping part of the sealing resin sheet piece arrange | positioned at the gap | interval part 9 or the margin part 10 was 1.2 mm.

  The entire periphery of the end face of the laminate 60 obtained in this way was covered with a bleeder 62, and put into a rubber bag 61 as a sealing treatment container, and the bag 61 was sealed. The reason why the end surface of the laminated body 60 is covered with the bleeder 62 is to prevent the molten resin inside the laminated body 60 from flowing out and to secure a discharge route for air from the inside of the laminated body 60.

  A plurality of sets of the rubber bags 61 are arranged on a shelf 67 provided in a hot stove 66. Each rubber bag 61 is connected to an evacuable pipe 63, which is connected to a vacuum pump 65 via a pressure regulating valve 64. A schematic diagram of the sealing processing apparatus is shown in FIG.

  After setting as described above, the sealing treatment operations of the following steps 2 to 6 were performed. The temperature and pressure at this time were controlled as shown in Table 1 and FIG. At this time, the temperature is the temperature in the hot stove 66 and the pressure is the pressure set by the pressure regulating valve 64. Note that Step 1 which is “a step of heating the sealing resin while maintaining the pressure in the sealing treatment container at 0.05 MPa or higher” is not employed in this embodiment. Since the sealing resin sheet piece is disposed in the gap portion 9 between the solar cells 4 and the tempered bent glass is used for both the light-receiving surface side transparent plate 2 and the back surface plate 3, step 1 is not adopted. However, cell cracks and substrate cracks can be prevented.

Step 2: “Step of reducing the pressure in the sealing treatment container to a pressure of 0.01 MPa or less at a temperature lower than the melting point of the sealing resin”
While starting to raise the temperature from room temperature (27 ° C.), pressure reduction was started. After about 1 minute, the pressure dropped to less than 0.005 MPa.

Step 3: “Step of raising the temperature to a temperature equal to or higher than the melting point of the sealing resin with reduced pressure”
Continue heating to 40 ° C in 30 minutes from the start of temperature rise, maintain (balancing) at 40 ° C for 10 minutes, raise the temperature to 50 ° C over 75 minutes, maintain at 50 ° C for 10 minutes, 105 minutes The temperature was raised to 60 ° C. over 10 minutes, maintained at 60 ° C. for 10 minutes, raised to 71 ° C. (melting point of the sealing resin) over 120 minutes, and maintained for 10 minutes.

Step 4: “Step of increasing the pressure in the sealing treatment container”
The temperature was raised from 71 ° C. to 90 ° C. over 90 minutes, and at the same time, the pressure that was less than 0.005 MPa was increased to 0.07 MPa over 90 minutes. At this time, the ratio of the pressure increase rate (MPa / min) to the temperature increase rate (° C / min) was 0.0037 (MPa / ° C). Thereafter, the temperature was maintained at 90 ° C. for 30 minutes, cooled to 40 ° C. over 60 minutes, maintained at 40 ° C. for 30 minutes, and a pressure of 0.07 MPa was maintained during that time.

Step 5: “Step of raising the temperature to a temperature range where the crosslinking reaction proceeds to advance the crosslinking reaction”
Subsequently, the temperature was raised from 40 ° C. to 155 ° C. over 90 minutes and maintained at 155 ° C. for 36 minutes to proceed the crosslinking reaction. During this time, the pressure of 0.07 MPa was maintained.

Process 6: “Cooling process”
Then, it cooled from 155 degreeC to 40 degreeC over 60 minutes. When the temperature reached 40 ° C., the pressure was increased from 0.07 MPa to 0.1 MPa (atmospheric pressure) over about 1 minute, and the product was taken out from the hot stove 66.

  In the obtained solar cell module, there were no cell cracks or chipping, no wire breakage, no bubble residue was observed, and no protrusion or sink of the sealing resin at the periphery was observed. Moreover, the photovoltaic cells were regularly arranged and sealed. The thickness of the sealing resin layer is about 4 mm, and all the solar cells 4 arranged in the sealing resin layer are curved in substantially the same direction in the same direction as the light receiving surface side transparent plate 2 and the back plate 3. The appearance that the external light is reflected was beautiful.

It is a cross-sectional schematic diagram of an example of the solar cell module after sealing operation. It is a cross-sectional schematic diagram of an example of the laminated body before sealing operation. FIG. 3 is an enlarged schematic cross-sectional view of a laminate before the start of a sealing operation in the example of FIG. 2. FIG. 3 is an enlarged schematic cross-sectional view of a laminate in the middle of heating and heating in the example of FIG. 2. It is an expanded sectional schematic diagram of the laminated body after the sealing operation in the example of FIG. It is the figure (the 1) which showed the procedure of the lamination process in an Example. It is the figure (the 2) which showed the procedure of the lamination process in an Example. It is the figure (the 3) which showed the procedure of the lamination process in an Example. It is the figure (the 4) which showed the procedure of the lamination process in an Example. It is the figure which showed thickness distribution of the sealing resin sheet piece in an Example. It is the schematic of a sealing processing apparatus. It is the figure which showed the temperature and pressure at the time of the sealing process in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solar cell module 2 Light-receiving surface side transparent plate 3 Back surface plate 4 Solar cell 5 Resin 8 Conductor 9 Gap part 10 Blank part 20 1st sealing resin sheet 30 2nd sealing resin sheet 40-48 Sealing resin sheet piece 60 Laminate 61 Bag 66 Hot stove

Claims (13)

In the method for manufacturing a solar cell module in which a plurality of solar cells are sealed with resin between the light-receiving surface side transparent plate and the back surface plate, both the light-receiving surface side transparent plate and the back surface plate have a radius of curvature of 500 to 500. A curved surface of 10000 mm, a plurality of solar cells are arranged at intervals and connected to each other by a conductive wire, and substantially the entire surface of the light receiving surface side transparent plate is between the light receiving surface side transparent plate and the solar cells. A first sealing resin sheet that covers the solar cell, a second sealing resin sheet that covers substantially the entire surface of the back plate between the back plate and the solar battery cell, and a gap between the solar cells or the solar cell. After placing the sealing resin sheet piece thicker than the thickness of the solar battery cell in the blank area outside the battery cell, the air between the light receiving surface side transparent plate and the back plate is discharged and heated to heat the resin. Solar cell module characterized by melting and then cooling and sealing Manufacturing method. The method for manufacturing a solar cell module according to claim 1, wherein the sealing resin sheet piece is sandwiched between a first sealing resin sheet and a second sealing resin sheet. The manufacturing method of the solar cell module of Claim 1 or 2 with which the thickness of the said sealing resin sheet piece is thicker than the total value of the thickness of a photovoltaic cell, and the thickness of conducting wire. The manufacturing method of the solar cell module in any one of Claims 1-3 in which the thickness of the said sealing resin sheet piece is 0.3 mm or more thicker than the thickness of a photovoltaic cell. The manufacturing method of the solar cell module according to any one of claims 1 to 4, wherein the sealing resin sheet piece has a thickness of 0.5 to 2 mm. When sealing in the sealing process container, the process of heating the sealing resin while maintaining the pressure in the sealing process container at 0.05 MPa or more (step 1), the sealing process at a temperature below the melting point of the sealing resin A step of depressurizing the inside of the container to a pressure of 0.01 MPa or less (step 2), a step of raising the temperature to a temperature equal to or higher than the melting point of the sealing resin with the pressure reduced (step 3), and increasing the pressure in the sealing treatment vessel The manufacturing method of the solar cell module in any one of Claims 1-5 which perform sealing operation which consists of each process of the process to perform (process 4) and the process to cool (process 6). When the sealing resin sheet is made of a crosslinkable thermoplastic resin and is sealed in the sealing treatment container, the pressure in the sealing treatment container is reduced to a pressure of 0.01 MPa or less at a temperature lower than the melting point of the sealing resin. The step (step 2), the step of raising the temperature to a temperature equal to or higher than the melting point of the sealing resin while reducing the pressure (step 3), the step of raising the pressure in the sealing treatment container (step 4), and the crosslinking reaction proceed. The manufacturing of the solar cell module according to any one of claims 1 to 5, wherein a sealing operation including each step of a step of raising the temperature to a temperature range and advancing a crosslinking reaction (step 5) and a step of cooling (step 6) is performed. Method. A solar cell module in which a plurality of solar cells are sealed with resin between a light-receiving side transparent plate and a back plate, and both the light-receiving side transparent plate and the back plate have a radius of curvature of 500 to 10,000 mm. A solar cell module having a curved line, a plurality of solar cells arranged at intervals and connected to each other by a conductive wire, and having no spacer on the periphery of the sealing resin layer. The solar cell module according to claim 8, wherein the number of the solar cells is 6 or more. The solar cell module according to claim 8 or 9, wherein the solar cell is curved in the same direction as the light-receiving surface side transparent plate and the back plate in the sealing resin layer. The solar cell module according to claim 8, wherein the sealing resin layer has a thickness of 2 to 6 mm. The solar cell module according to any one of claims 8 to 11, wherein both the light-receiving side transparent plate and the back plate are bent glass. The solar cell module according to any one of claims 8 to 12, wherein the sealing resin is a kind of resin selected from the group consisting of an ethylene-vinyl acetate copolymer, polyvinyl butyral, and polyurethane.

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