JP2012069986A - Method for producing solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a solar cell module by which cracking of solar cells can be prevented and solar cell modules can be produced with high productivity by a simple procedure.SOLUTION: A laminated body 60 is fabricated by disposing: a first sealing resin sheet 20, which substantially covers the entire surface of a light receiving side transparent board 2, between the light receiving side transparent board and a solar cell 4; a second sealing resin sheet 30, which substantially covers the entire surface of a rear board 3, between the rear board and the solar cell; and pieces of sealing resin sheet 40 to 43, which have a thickness larger than that of the solar cell, in gaps between the solar cells or on margin areas on external sides of the solar cell. The laminated body is put in a sealing process container composed of a gas impermeable flexible sheet, and the sealing process containers are introduced into an oven and arranged in parallel at intervals each other. Inside the sealing process container is depressurized to exhaust the air between the light receiving side transparent board and the rear board. The laminated body is heated to melt the sealing resin by permitting a hot blast to flow parallel to the laminated body in the oven, and then the laminated body is cooled to solidify the sealing resin.

Description

  The present invention relates to a method for manufacturing a solar cell module and a solar cell module. In particular, the present invention relates to a method for manufacturing a solar cell module in which solar cells are sealed with resin between a light-receiving surface side transparent plate and a back plate.

  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.

  As a method for sealing a plurality of solar cells in a solar cell module, a method using a double vacuum chamber type laminator and a method using a single vacuum chamber type laminator are mainly known. The double vacuum chamber type laminator is capable of independently adjusting the degree of vacuum in the two chambers separated by a gas-impermeable flexible sheet. The structure is complicated. On the other hand, a single vacuum type laminator tends to cause residual bubbles and cell cracking, but the laminator structure is simple. These laminators are properly used according to the specifications of the solar cell module. In many cases, in any of the above laminators, a laminate is placed on a plate incorporating a heater, and the space in which the laminate is present is heated and sealed while being evacuated.

  In JP-A-61-69179 (Patent Document 1), a solar cell panel laminate 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. Are listed. 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. The double-vacuum laminator used in the examples of this publication places the laminate on a hot plate and heats it.

  Japanese Patent Application Laid-Open No. 59-22978 (Patent Document 2) describes a filling adhesive sheet for a solar cell module, which contains an ethylene copolymer and an organic peroxide and has 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 example of this 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. The laminator used in the examples of the publication is a vacuum laminator separated into two chambers by silicone rubber.

  In Japanese Patent Laid-Open No. 9-36405 (Patent Document 3), a photovoltaic element is formed as a laminated body through a sealing material resin between a front surface member and a back surface member, and the laminated 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. According to the method described in the publication, even if a single vacuum chamber type laminator having a simple structure is used, the generation of residual bubbles can be suppressed. The single-vacuum type laminator used in the embodiment of the publication has a laminated body that is a module placed on a plate in which a heater is embedded, and a silicone rubber sheet is placed on the laminated body, and an exhaust port of the plate. It can be evacuated with a vacuum pump. 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.

  By the way, the installation place of the solar cell has been diversified recently, and it is used not only on the roof of the building but also on the wall portion. 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. Moreover, solar cell modules having various shapes and sizes corresponding to the design of each building are required. 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. Furthermore, in recent years, a method of constructing a glass wall surface of a building by a DPG (Dot Point Glazing) method has been widely adopted. In this case, it is necessary to insert a metal fitting into a hole opened in the glass. Become. Thus, when manufacturing various solar cell modules, it is difficult to seal with a laminator having the above-described structure.

  Moreover, 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 in which the cell is hardly damaged as much as possible is also desired.

  In the utility model registration No. 2500974 (Patent Document 4), 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. It is described that EVA is used as an adhesive sheet and plate glass is used on both sides as a plate-like body.

  Japanese Patent Laid-Open No. 2003-110127 (Patent Document 5) 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 Patent Application Laid-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.

  In Japanese Patent Laid-Open No. 9-92867 (Patent Document 7), a filling sheet made of EVA resin is arranged on both sides of a solar battery cell in advance, and vacuum heating is performed to join layers to form a preformed sheet. A method for manufacturing a solar cell module is described in which the preformed sheet is placed on a curved glass surface 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, when sealing solar cells between curved substrates, or even solar cell modules having metal fittings, sealing can be performed, and solar cell modules having various shapes and sizes can be manufactured. A stopping method is desired. At the same time, it is difficult to cause cell breakage, can be sealed with a simple operation and at low cost, solar cells can be regularly arranged, and a solar cell module having excellent adhesion and durability can be obtained. A sealing method that can be used is also desired.

JP-A-61-69179 JP 59-22978 JP-A-9-36405 Utility Model Registration No. 2500974 Japanese Patent Laid-Open No. 2003-110127 JP 2001-7376 A JP-A-9-92867

  The present invention has been made to solve such problems, and in a method for manufacturing a solar cell module in which solar cells are sealed with a resin, solar cell modules having various shapes and sizes can be easily used. It is an object of the present invention to provide a method for manufacturing a solar cell module that can be sealed with a simple operation and at low cost. Moreover, it aims at providing the solar cell module provided with the metal fitting for module fixation.

In the method for manufacturing a solar cell module, the solar cell is sealed with a resin between the light-receiving surface side transparent plate and the back plate.
A first sealing resin sheet that covers substantially the entire surface of the light receiving surface side transparent plate is disposed between the light receiving surface side transparent plate and the solar battery cell, and substantially the entire surface of the back surface plate is disposed between the back surface plate and the solar cell. A second encapsulating resin sheet covering the substrate to produce a laminate,
Put the laminate in a sealing treatment container made of a gas impermeable flexible sheet,
A plurality of sealing treatment containers containing the laminate are introduced into an oven and arranged in parallel with a space between each other,
Depressurize the inside of the sealing treatment container to discharge air between the light receiving surface side transparent plate and the back plate,
In the oven, the laminate is heated by flowing hot air in a direction parallel to the laminate to melt the sealing resin,
The problem is solved by providing a method for manufacturing a solar cell module, wherein the sealing resin is solidified by subsequent cooling.

  By using a plurality of sealing treatment containers made of a gas impermeable flexible sheet, various shapes of laminates can be accommodated therein. In addition, by simultaneously heating a plurality of sealing processing containers in an oven, it is possible to perform a sealing operation with a simple operation and at a low cost. At this time, in the oven, it is possible to efficiently and evenly transfer the heat by arranging the sealing processing containers in parallel with a space therebetween and by flowing hot air in a direction parallel to the laminated body. is there.

  At this time, it is preferable that the sealing treatment container is a bag made of a gas-impermeable flexible sheet. It is also preferable that the outer edge of the laminate is covered with a fabric having air permeability before being put into a sealing treatment container. It is a preferred embodiment that the laminate is heated while maintaining the inside of the oven at substantially atmospheric pressure. It is preferable that a plurality of solar cells are arranged at intervals and connected to each other by a conductive wire. At this time, a plurality of sets in which a plurality of solar cells are connected to each other in a series direction by a conductive wire It is also a preferred embodiment to form the laminate by opening and arranging in parallel, and to heat the airflow in the oven in a direction parallel to the series direction. It is also preferable that the oven has a hot air inlet and a hot air outlet provided on the opposite side. The sealing processing container is connected to a vacuum pump via a pipe, each of the plurality of pipes is provided with a set of a pressure gauge and a valve, and connected to the sealing processing container in which leakage is detected by the pressure gauge. It is also preferred that the valve is closed. It is also preferable that each of the sealing processing containers is connected to a vacuum pump via a pipe, and a tank is provided between the sealing processing container and the vacuum pump. At this time, it is preferable to have a pressure gauge for measuring the pressure in the tank and a valve for introducing outside air into the tank, and finely adjust the pressure in the tank. It is also preferable to provide at least one temperature control chamber adjacent to the oven and perform a preheating operation or a cooling operation in the temperature control chamber.

  In the above method, in the laminate, it is preferable to dispose a sealing resin sheet piece thicker than the thickness of the solar battery cell in a gap between the solar battery cells or a blank part outside the solar battery cell. It is a preferred embodiment that both the light-receiving side transparent plate and the back plate are glass plates. It is also a preferred embodiment that at least one of the light receiving surface side transparent plate and the back plate is curved. It is also a preferred embodiment that the laminate has a member protruding outward from the light-receiving surface side transparent plate or the back plate. At this time, it is preferable that the member protruding outward is a bracket for fixing the module. 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.

  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 processing container at a temperature lower than the melting point of the sealing resin when sealing in the sealing processing container. Reducing the pressure to 0.01 MPa or less (step 2), 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 increasing the pressure in the sealing treatment container (Step 4), a sealing operation comprising each step of the step of raising the temperature to the temperature range where the crosslinking reaction proceeds (step 5) and the step of cooling (step 6) to advance the crosslinking reaction is performed.

  The above-described problem is a solar cell module having a sealing resin layer between a light-receiving surface-side transparent plate and a back plate, and solar cells sealed in the sealing resin layer, The metal fitting is inserted into a through hole formed in either the light-receiving surface side transparent plate or the back plate, and the head side end of the metal fitting is disposed on the sealing resin layer side. This is solved by providing a solar cell module characterized in that the opposite end of the projection protrudes outward. At this time, it is preferable that no spacer is provided on the periphery of the sealing resin layer. In addition, it is also preferable that the through hole is a countersink, and the head of the metal fitting is fitted in the countersink.

  According to the method for manufacturing a solar cell module of the present invention, in a method for manufacturing a solar cell module in which solar cells are sealed with a resin, solar cells with various shapes and dimensions can be easily operated and at low cost. Can be sealed.

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. It is a cross-sectional schematic diagram of another example of the laminated body before sealing operation. It is a cross-sectional schematic diagram of another example of the laminated body before sealing operation. It is an expanded sectional schematic diagram of the laminated body before the sealing operation start in the example of FIG. FIG. 3 is an enlarged schematic cross-sectional view of a laminate in the middle of 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 a schematic diagram of an example of a sealing processing apparatus. It is the schematic diagram which showed the case where it heats so that the airflow in an oven may become the direction parallel to the serial direction of a photovoltaic cell. It is the schematic diagram which showed the case where it heats so that the airflow in an oven may become the direction perpendicular | vertical to the serial direction of a photovoltaic cell. It is the figure (the 1) which showed the procedure of the lamination process in Example 1 and 2. FIG. FIG. 3 is a diagram (part 2) illustrating a procedure of a laminating process in Examples 1 and 2. FIG. 3 is a diagram (No. 3) illustrating a procedure of a stacking process in Examples 1 and 2. It is the figure which showed the temperature and the pressure at the time of the sealing process in Example 1 and 2. FIG.

  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. 2-4 is a cross-sectional schematic diagram of an example of the laminated body before sealing operation. FIG. 5 is an enlarged schematic cross-sectional view of the laminate before the start of the sealing operation in the example of FIG. 6 is an enlarged schematic cross-sectional view of the laminate in the middle of heating and heating in the example of FIG. FIG. 7 is an enlarged schematic cross-sectional view of the laminate after the sealing operation in the example of FIG. FIG. 8 is a schematic view of an example of a sealing processing apparatus. FIG. 9 is a schematic view showing a case where heating is performed so that the airflow in the oven is parallel to the series direction of the solar cells. FIG. 10 is a schematic diagram illustrating a case where heating is performed so that the airflow in the oven is in a direction perpendicular to the series direction of the solar battery cells.

  The solar cell module 1 obtained by the manufacturing method of the present invention is obtained by sealing solar cells 4 with a resin 5 between a light-receiving surface side transparent plate 2 and a back plate 3. The number of solar cells 4 sealed in the solar cell module 1 may be one, but usually a plurality of solar cells 4 are sealed. 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. A schematic cross-sectional view in that case is shown in FIG.

  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 are generally thin plates having a thickness of 1 mm or less, more generally 0.5 mm or less, and are often rectangular with one side being 5 cm or more. As the material of the substrate, a semiconductor substrate such as silicon or germanium, a glass substrate, a metal substrate, or the like can be used, but the silicon substrate is most important in practical use. In the case of a silicon substrate, thinning is desired from the viewpoint of cost. However, since it is a hard and brittle material, it is particularly easy to break at the time of sealing, and it is necessary to seal it carefully.

  The number of solar cells 4 enclosed in one solar cell module 1 is not particularly limited, and may be only one. In that case, only the wiring from the solar battery cell 4 to the outside is connected. The larger the number of solar cells 4 enclosed in one solar cell module 1, the larger the overall size of the solar cell module 1. Since the large-sized solar cell module 1 is often custom-made in various shapes or dimensions, there is a great practical advantage in adopting the manufacturing method of the present invention. Therefore, it is preferable that 10 or more, preferably 30 or more solar cells 4 are arranged in one solar cell module 1. Further, when a large number of solar cells 4 are enclosed, bubbles are likely to be generated, and when the solar cells 4 are moved during the sealing operation, it is likely to cause a problem in appearance. Moreover, since the defective product rate resulting from the failure | damage of the photovoltaic cell 4 increases, so that the number of the photovoltaic cells 4 enclosed with one solar cell module 1 increases, it is necessary to seal carefully. .

  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 located apart from each other are connected, or a hole is formed in the back plate 3 to pull out 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.

  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. However, since a glass plate having a large surface compressive stress is usually produced by heating and quenching a float plate glass, occurrence of a certain strain is inevitable. Therefore, due to the warpage of the glass, an excessive load is easily applied to some of the solar cells 4 at the time of sealing, and there is a great need to pay attention to cell cracking.

  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. As the surface compressive stress is increased, the strength is improved, but warpage tends to increase and the manufacturing cost tends to increase. The double-strength glass is preferable in that it is easy to produce a glass with relatively little warpage and does not fall into a small piece when dropped. The glass plate is selected according to the use and purpose.

  As the back plate 3, the same one as the light receiving surface side transparent plate 2 is preferably used. In addition, when importance is attached to the light weight of the module, a thin and flexible material such as a plastic film can be used. 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 glass, especially a glass plate whose surface compressive stress is 20 MPa or more for the same reason as the light-receiving surface side transparent plate 2.

The material of the glass is not particularly limited, and soda lime glass is preferably used. In particular, the light-receiving surface side transparent plate 2 is preferably a highly transmissive glass (so-called white plate glass). 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, use heat ray reflection glass, heat ray absorption glass, or the like. 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. When using such a thick glass plate, the influence of its own weight is great, and care should be taken because the cell may be damaged when the glass plate is stacked on the cell before bonding. 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 1 m < ² > or more, the actual profit which employ | adopts the manufacturing method of this invention is large.

  The light-receiving surface side transparent plate 2 and the back plate 3 used in the present invention may be flat or curved. When at least one of the light-receiving surface side transparent plate and the back plate is curved, it is difficult to seal using a widely used laminator, so the advantage of employing the manufacturing method of the present invention is great. . Although portions other than the solar battery cells 4 may be greatly curved, it is usually preferable that the solar cells 4 have a curvature with a curvature radius of 500 to 10,000 mm in the region where the solar battery cells 4 are present. When the radius of curvature is less than 500 mm, it may be 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 may be 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. In this case, the curvature radius referred to in the present invention refers to the minimum curvature radius in the region where the solar battery cell 4 is present.

  Moreover, the light-receiving surface side transparent plate 2 and the back plate 3 used in the present invention may have holes. For example, in recent years, a method of constructing a glass wall surface of a building by a DPG (Dot Point Glazing) method has been widely adopted, but in this case, it is necessary to insert a metal fitting into a hole provided in the glass. Then, the light-receiving surface side transparent plate 2 and the back plate 3 having holes are sealed. At this time, the hole may be sealed in a state in which a metal fitting is attached. In such a case, the advantage of employing the manufacturing method of the present invention using the sealing treatment container 61 made of a flexible sheet is particularly great. .

  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 is possible to achieve excellent durability and adhesiveness. 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 production method of the present invention will be described.

  First, the example of FIG. 2 will be described. In the example of FIG. 2, the flat light receiving surface side transparent plate 2 and the back plate 3 are used. It is an example which arrange | positions the sealing resin sheet piece thicker than thickness. FIG. 2 is a schematic cross-sectional view of an example of the laminated body 60 before the sealing operation, and shows a cross section cut in parallel to the direction in which the plurality of solar battery cells 4 are connected in series.

  First, the second sealing resin sheet 30 is overlaid on the back plate 3 so as to substantially cover the entire surface. In the example of FIG. 2, the operation of stacking the back plate 3 from below is performed, but the light receiving surface side transparent plate 2 may be stacked in reverse order from the bottom first.

  The thickness of the second sealing resin sheet 30 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 second sealing resin sheet 30 is preferably configured by laminating a plurality of sealing resin sheets. This is because it becomes easy to adjust the thickness of the second sealing resin sheet 30 according to the use and required performance. In the example of FIG. 2, the second sealing resin sheet 30 is configured by overlapping three sealing resin sheets 31, 32, and 33. The second sealing resin sheet 30 only needs to cover substantially the entire surface of the back plate 3, and a part of the second sealing resin sheet 30 may be missing due to the arrangement of the conductive wires or the like, and is disposed side by side. Moreover, you may be comprised from the several sealing resin sheet.

  The solar battery cell 4 is placed on the second sealing resin sheet 30. 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.

  Subsequently, in the blank portion 10 outside the solar battery cell 4, on the second sealing resin sheet 30, 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, the load of the light-receiving surface side transparent plate 2 can be prevented from being directly applied to the solar cells 4 arranged in the module, and cell cracking in the decompression process can be prevented. In particular, according to the manufacturing method of the present invention, a load derived from atmospheric pressure is received from above and below the laminated body 60 during the sealing operation, and thus such a configuration is preferable. 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, 42, The actual profit of arranging 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, and more preferably 2 mm or less. When the thickness is too thick, bubbles easily remain around the solar battery cell 4.

  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, a sealing resin sheet piece disposed substantially continuously over the entire periphery of the blank portion 10 on the second sealing resin sheet 30 in the blank portion 10 outside the solar battery cell 4. 40 and a sealing resin sheet piece 41 that is overlapped with each other and spaced from each other are disposed, and the first sealing resin sheet 20 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 width 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 second sealing resin sheet 30 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. FIG. 5 is an enlarged schematic cross-sectional view of the laminate before starting the sealing operation, FIG. 6 is an enlarged schematic cross-sectional view of the laminate in the middle of heating and heating, and FIG. 7 is an enlarged cross-sectional view of the laminate after the sealing operation. It is a 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 first sealing resin sheet 20 is mounted thereon. The suitable structure and suitable thickness of the 1st sealing resin sheet 20 are the same as that of the 2nd sealing resin sheet 30. FIG. In the example of FIG. 2, the first sealing resin sheet 20 is configured by stacking three sealing resin sheets 21, 22, and 23. Finally, the light-receiving surface side transparent plate 2 is placed on the first sealing resin sheet 20.

  Next, the example of FIG. 3 will be described. The example of FIG. 3 is an example in which both the light-receiving surface side transparent plate 2 and the back plate 3 are curved. FIG. 3 is a schematic cross-sectional view of an example of the laminated body 60 before the sealing operation, and shows a cross section cut in parallel to the direction in which the plurality of solar battery cells 4 are connected in series. In the example of FIG. 3, the operation of stacking the light-receiving surface side transparent plate 2 from below is performed, but the back plate 3 may be stacked in reverse order from the bottom first. 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.

  In the example of FIG. 3, the first sealing resin sheet 20, the solar battery cell 4, the sealing resin sheet pieces 40, 41, 42, 43 and the second sealing resin sheet 30 are placed on the light-receiving surface side transparent plate 2. Although this order is repeated, the specific method is the same as the example of FIG. 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.

  As in the example of FIG. 3, when at least one of the light-receiving surface side transparent plate 2 and the back plate 3 is curved, it is difficult to uniformly heat the laminate 60 by heat transfer from the heater. Therefore, it is particularly preferable to employ the manufacturing method of the present invention. Further, in order to prevent the light-receiving surface side transparent plate 2 or the back plate 3 from being broken by uneven loads from above and below, the sealing treatment container 61 is a bag made of a gas impermeable flexible sheet. preferable.

  Next, the example of FIG. 4 will be described. The example of FIG. 4 is an example in which a countersink 52 is provided in the back plate 3 and a module mounting bracket 53 is inserted therein. FIG. 4 is a schematic cross-sectional view of an example of the laminated body 60 before the sealing operation, and shows a cross section cut in parallel to the direction in which the plurality of solar cells 4 are connected in series. The stacking order is not particularly limited, but it is preferable from the viewpoint of workability to stack the module mounting bracket 53 so that the side from which the tip end portion 54 protrudes is on the upper side. Therefore, in the example of FIG. 4, it is preferable to perform an operation of overlapping the light-receiving surface side transparent plate 2 from below.

  In the example of FIG. 4, the first sealing resin sheet 20, the solar battery cell 4, the sealing resin sheet pieces 40, 41, 42, 43 and the second sealing resin sheet 30 are placed on the light receiving surface side transparent plate 2. Although this order is repeated, the specific method is the same as the example of FIG.

  Finally, the back plate 3 having the countersunk hole 52 is placed on the second sealing resin sheet 30. At this time, the head portion 55 of the module mounting bracket 53 is fitted into the countersunk hole 52. By disposing the head 55 of the module mounting bracket 53 inside the solar cell module 1 before sealing, the module mounting bracket 53 can be firmly fixed without making a hole in the light receiving surface side transparent plate 2. it can. The form of the module mounting bracket 53 is not particularly limited, but it is preferable to have a head portion 55 having a shape that can follow the countersunk hole 52. Moreover, threading etc. may be given suitably.

  In the above, the structure of the laminated body 60 before sealing operation was demonstrated using FIGS. 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.

  FIG. 8 is a schematic diagram of an example of a sealing processing apparatus. This sealing processing apparatus has a plurality of sealing processing containers 61 for accommodating the laminated body 60 therein, and can perform an air discharging operation and a heating operation. At this time, a part or all of the sealing processing container 61 is made of a gas non-permeable flexible film. The material of the film may be a gas non-permeable flexible film, which has a certain degree of flexibility and strength, and when the inside of the film is evacuated, the external pressure is uniformly applied to the entire laminate 60. If it becomes, it will not specifically limit, The sheet | seat and film of rubber | gum and resin can be used. At this time, it is preferable to use a bag made of a flexible film which is entirely impermeable to gas. In this case, since the sealing container 61 is a mere bag, it can be flexibly adapted when manufacturing solar cell modules of various shapes and sizes, and products of various sizes such as building materials can be used. Suitable for applications that require manufacturing.

  In particular, in the laminate 60, when at least one of the light receiving surface side transparent plate 2 and the back plate 3 is curved, it is preferable to use such a sealing processing container 61. It is possible to prevent the light receiving surface side transparent plate 2 or the back surface plate 3 from cracking when the inside of the sealing processing container 61 is depressurized and a load from above and below is applied to the laminated body 60. In this case, it is preferable to seal the bag, which is the sealing processing container 61, along the surfaces of the light-receiving surface side transparent plate 2 and the back plate 3.

  Moreover, it is preferable to use such a sealing processing container 61 also when the laminated body 60 has the member which protruded outside from the light-receiving surface side transparent plate 2 or the back surface board 3. FIG. Also in this case, it is preferable to seal the bag, which is the sealing processing container 61, along the shape of the protruding member. Depending on the shape of the protruding member, a bag having a pocket corresponding to the shape may be used. In order to prevent an excessive load from being applied to the protruding portion, it is also preferable that the protruding portion is covered with a cover that is not easily deformed during decompression and then introduced into the sealing processing container 61. By doing so, the sealing process vessel 61 can be prevented from being damaged.

  When the laminated body 60 is introduced into the sealing processing container 61, the outer edge 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.

  In this way, the plurality of sealing processing containers 61 in which the stacked body 60 is put are introduced into the oven 63 and arranged in parallel with a space between each other. Thereby, the laminated bodies 60 in the sealing processing container 61 are arranged in parallel to each other. The plurality of sealing processing containers 61 are preferably arranged so as to overlap each other in the vertical direction. The method of arranging with a predetermined interval is not particularly limited, and examples thereof include a method of providing a shelf having a predetermined interval in the oven 63.

  The laminated body 60 is heated by flowing hot air in a direction parallel to the laminated body 60 in the oven 63. By flowing hot air in a direction parallel to the stacked body 60, heat can be efficiently and uniformly transmitted to the stacked body 60. At this time, it is preferable that the hot air also contacts the lower surface of the sealing processing container 61. For this purpose, a method of arranging a spacer between the sealing processing container 61 and the shelf, or the shelf itself as a net shelf. The method to do is adopted suitably. The method for supplying the hot air is not particularly limited, and a heater may be provided in the oven 63 and the hot air may flow in a direction parallel to the stacked body 60 using a fan. However, a method in which a heater is provided outside the oven 63 and hot air is introduced into the oven 63 is preferable because it facilitates uniform heating. In this case, the oven 63 has a hot air inlet and a hot air outlet provided on the opposite side, and a plurality of sealing processing containers 61 are arranged between the passages flowing from the hot air inlet to the hot air outlet. It is preferred that In addition, it is preferable from the viewpoint of apparatus cost that the laminate is heated while maintaining the inside of the oven 63 at substantially atmospheric pressure.

  In many solar cell modules, a plurality of sets are prepared in which a plurality of solar cells 4 are connected to each other in the series direction by conducting wires 8, and the plurality of sets are arranged in parallel at intervals to form a stacked body 60. Produced. Such a relationship between the direction of the laminated body 60 and the direction of the airflow in the oven 63 is important for manufacturing a solar cell module in which the solar cells 4 are regularly arranged. FIG. 9 shows a case where heating is performed so that the airflow in the oven 63 is parallel to the series direction. FIG. 10 shows a case where heating is performed so that the airflow in the oven 63 is in a direction perpendicular to the series direction. The arrows in FIGS. 9 and 10 indicate the direction of airflow. As will be described later, when heating is performed so that the airflow in the oven 63 is in a direction perpendicular to the series direction, the rows of solar cells 4 connected in series are shown in FIG. It became clear that it curves like a one-dot chain line. This is considered to be because there is a distribution in the speed at which heat is transmitted in the laminate 60. Therefore, it has become clear that in order to manufacture regularly arranged solar cell modules, it is preferable to heat the oven 63 so that the airflow in the oven 63 is parallel to the series direction.

  In the sealing process, the inside of the sealing process container 61 is depressurized to discharge air between the light receiving surface side transparent plate 2 and the back plate 3. In the sealing processing apparatus of FIG. 8, a pipe 64 for exhausting air is connected to each sealing processing container 61. Three pipes 64 are collected and connected to the pipe 65. Further, six pipes 65 (partially omitted) collected in this way are connected to the tank 66. The tank 66 is connected to a vacuum pump 67, whereby the air inside the sealing processing container 61 can be discharged. The number of the sealing processing containers 61 is not particularly limited as long as it is plural, but in consideration of production efficiency, it is preferably 6 or more, and more preferably 12 or more.

  A pressure gauge 69 is connected to each of the six pipes 65 via a valve 68, and an electromagnetic valve 70 capable of blocking the flow in the pipe 65 is provided. As a result, when a leak occurs in any of the sealing processing containers 61 connected to the pipe 65, the pressure gauge 69 detects an increase in pressure, and the control circuit 71 sends a signal to the solenoid valve 70 to 70 is closed. Accordingly, even if a leak occurs in one sealing processing container 61 during the sealing operation, it is possible to prevent the other sealing processing containers 61 from being adversely affected. The sealing treatment container 61 used in the present invention is made of a flexible sheet and needs to be prepared in various shapes according to the form of the solar cell module, and thus there is a risk of leakage. Moreover, the solar cell module is quite expensive. Therefore, it is preferable to employ such a control method. In the example of FIG. 8, one control is performed for each of the three sealing processing vessels 61, but this is based on a balance between the equipment cost and the effect. The set of the pressure gauge 69 and the electromagnetic valve 70 may be two sets or more, preferably three sets or more, more preferably five sets or more. An alarm signal can be issued from the control circuit 71 to notify the operator.

  The six pipes 65 are connected to the tank 66, and all the sealing processing containers 61 communicate with the tank 66 in a state where the electromagnetic valve 70 is open. The air in the tank 66 is discharged by a vacuum pump 67. Further, outside air can be introduced into the tank 66 via the control valve 72.

  As will be described later, the pressure in the sealing processing container 61 needs to be strictly controlled. In the sealing processing apparatus of FIG. 8, by controlling the pressure in the tank 66, the pressures in all the sealing processing containers 61 can be controlled simultaneously. The pressure inside the tank 66 is measured by a pressure gauge 74 connected via a valve 73, and a control circuit 75 that receives this pressure data sends a signal to the control valve 72 to finely adjust it to a desired pressure while taking in outside air. To do. During this time, the vacuum pump 67 continues to operate. By controlling the tank 66 having a relatively large capacity while taking in outside air, the pressure in the sealing processing container 61 can be finely adjusted.

  In addition, before starting the decompression operation in the sealing processing container 61, the inside of the tank 66 may be decompressed in advance by operating the vacuum pump 67 with the electromagnetic valve 70 and the control valve 72 closed. it can. In this case, the air in the sealing processing container 61 can be quickly discharged by opening the electromagnetic valve 70. This helps to quickly depressurize the inside of the sealing processing container 61 even when the exhaust capability of the vacuum pump 67 is small.

  The capacity of the tank 66 is not particularly limited, but is preferably 10 liters or more, and more preferably 20 liters or more. Further, when the capacity is too large, the pressure control by the control valve 72 may not be performed quickly. The sealing processing apparatus used in the examples described later was provided with a 50-liter tank 66.

  As will be described later, it may be preferable to preheat the inside of the sealing processing container 61 before the pressure is reduced. In such a case, a preheating operation can be performed in the oven 63, but a temperature control chamber (not shown) adjacent to the oven 63 is provided, and the preheating operation is performed in the temperature control chamber before the oven 63 is operated. It is preferable from the aspect of utilization efficiency of the oven 63 to perform the sealing treatment inside. By doing so, it is possible to preheat other modules while sealing the modules in the oven 63.

  In addition, when the sealing resin is melted in the sealing processing container 61 and then cooled under atmospheric pressure, it can be cooled in the oven 63 or externally. . However, when cooling in the oven 63, the usage time of the oven 63 becomes longer, and thus the productivity is lowered. On the other hand, when cooling outside, it is difficult to adjust the cooling rate. Therefore, it may be preferable to provide a temperature control chamber adjacent to the oven 63 and perform the sealing process in the oven 63 before cooling in the temperature control chamber. By doing so, it is possible to cool other modules while sealing the modules in the oven 63. The effect is particularly great when the cooling rate is to be slowed down.

  The temperature control chamber is not particularly limited as long as it can adjust the internal temperature and is provided adjacent to the oven 63. It is preferable to have a door for introducing the sealing container 61 from the outside into the temperature control chamber, and to have a door between the oven 63 and the temperature control chamber. For example, it is possible to use an apparatus that can move a cart on which a large number of sealing processing containers 61 are placed and guide the cart from the outside to the oven 63 through the temperature control chamber. Only one temperature control chamber can be provided for one oven 63, or two or more temperature control chambers can be provided.

  When one temperature control chamber is provided, it can be used for either the preheating operation or the cooling operation. For example, the sealing treatment container 61 can be introduced into the temperature control chamber from the outside, preheated, introduced into the oven 63, sealed, and then led out. Alternatively, the sealing processing container 61 can be introduced from the outside into the oven 63 and sealed, and then introduced into the temperature control chamber, where it can be cooled, and then led out to the outside. In this case, the sealing process container 61 usually passes in one direction.

  When two temperature control chambers are provided, the sealing processing container 61 may be passed in one direction or reciprocated. When passing the sealing process container 61 in one direction, the sealing process container 61 is introduced into the temperature control chamber from the outside, preheated, introduced into the oven 63, sealed, It is introduced into the temperature control room, cooled, and then led out. In the case of reciprocating the sealing processing container 61, the sealing processing container 61 is introduced into the temperature control chamber from the outside, preheated, introduced into the oven 63, sealed, and then put into the same temperature control chamber. After returning and cooling operation, it is led out. In this case, the sealing process is performed in the oven 63 when the cooling operation and the preheating operation are performed in one temperature control chamber, and the oven 63 is performed when the cooling operation and the preheating operation are performed in another temperature control chamber. The sealing process will be performed. Thus, when reciprocating, it has the advantage that the space for circulating a trolley | bogie becomes unnecessary.

  Using the sealing processing apparatus as described above, 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.

  Especially, when sealing in the sealing process container 61, the process (step 1) of heating the sealing resin while maintaining the pressure in the sealing process container 61 at 0.05 MPa or more, less than the melting point of the sealing resin A step of reducing the pressure in the sealing treatment vessel 61 to a pressure of 0.01 MPa or less at a temperature (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 It is preferable to perform a sealing operation including the steps of increasing the pressure in the container 61 (step 4) and cooling (step 6).

  The step 1 is a step of heating the sealing resin while maintaining the pressure in the sealing processing container 61 at 0.05 MPa or more. By maintaining the pressure in the sealing processing container 61 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 stacked body 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.

  The pressure in the sealing processing container 61 in step 1 may be atmospheric pressure (0.1 MPa), but for example, the leakage of the sealing processing container 61 can be checked by reducing the pressure to 0.09 MPa or less. it can. In step 1, since the sealing resin is not yet melted, if there is a leak in the sealing processing container 61, it can be repaired at this stage. Since the sealing processing container 61 used in the manufacturing method of the present invention is made of a flexible sheet and easily breaks, it is preferable to reduce the pressure slightly as described above. 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 61 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 61 drops to 0.01 MPa or less in Step 2, and a passage for discharging the air inside the laminate 60 is provided. There is a risk of air bubbles remaining due to clogging. 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 the sealing process container 61 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 processing container 61 to a pressure of 0.01 MPa or less at a temperature lower than the melting point of the sealing resin. It is a process. 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 61 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 processing container 61, 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 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.

  Further, in step 4, it is preferable to have a process of simultaneously raising the temperature while increasing the pressure in the sealing processing vessel 61. 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

  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 particular, when the sealing resin (melting point: Tm (° C.)) is melted and then cooled, the time required for cooling from (Tm + 10) ° C. to (Tm−20) ° C. is 20 minutes or more. It is preferred to cool. The time is more preferably 30 minutes or more, and even more preferably 60 minutes or more. By slowly cooling in the vicinity of the melting point, it is possible to suppress residual stress and to suppress the occurrence of cell cracks.

  The main cause of cell cracking in the sealing operation is that when air is discharged between the light-receiving surface side transparent plate 2 and the back plate 3 to melt the resin, it receives a load from above and below. It is thought that there is. However, the present inventors have found that cell cracking does not occur at that timing, and cell breakage may occur during subsequent cooling while undamaged solar cells are present in the molten resin. . This is because, during the sealing operation, when a laminated body at a temperature higher than the melting point was observed, no cell cracking was found, and then cell cracking occurred during cooling at a relatively high rate in the atmosphere. This phenomenon has been clarified by the recognition of this phenomenon.

  The mechanism by which such a phenomenon occurs is not necessarily clear, but the following mechanism has been estimated. When the sealing resin in a molten state is cooled, the fluidity is lost at a temperature equal to or lower than the melting point, solidifies and shrinks. Such shrinkage is thought to occur mainly due to polymer crystallization. At this time, it is presumed that cell cracking has occurred due to stress assumed to occur inside the resin due to shrinkage. It is surprising that the shrinkage stress accompanying the solidification of the resin is a large force that can break the cell. On the other hand, it has become clear that the occurrence of cell cracking at this timing can be suppressed by reducing the cooling rate. The reason why cell cracking can be suppressed by lowering the cooling rate is not necessarily clear, but it is possible that the rate of crystallization can be reduced, or that stress relaxation can be facilitated. Here, when the sealing resin does not have a melting point, the melting point here may be replaced with a glass transition point or a softening point. Even when the sealing resin is an amorphous resin having no melting point, it is solidified with shrinkage near the glass transition point or softening point.

  In particular, when solar cells that are easily broken are used, it is preferable to perform sealing using such a method of cooling slowly. For example, it is suitable for sealing a solar cell having a large area, a solar cell having a small thickness, a solar cell having a light-transmitting small hole, a solar cell having an uneven surface, and the like.

  When a crosslinkable thermoplastic resin is used as the sealing resin, the pressure in the sealing process vessel 61 is increased after the step of raising the temperature to near the melting point of the sealing resin while reducing the pressure (step 3). It is preferable to have a step (step 5) for raising the temperature to a temperature range where the crosslinking reaction proceeds and a step (step 6) for cooling and a step (step 6) for cooling.

  In this case, it is also preferable to raise the pressure in the sealing treatment vessel 61 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 the pressure in the sealing treatment container 61 is increased, 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 61 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 61, 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, sink may occur depending on the configuration of the laminate 60. In such a case, it is preferable to set the pressure lower than the atmospheric pressure. Further, when the pressure is increased to the same pressure as the atmospheric pressure, it is difficult for the bleeder 62 to press around the laminated body 60 and the resin may protrude, so that the pressure lower than the atmospheric pressure is set even in such a case. It is preferable to do. 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, since the hot air is forcibly blown into the oven 63 by a fan, the atmospheric pressure is slightly higher than the 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.

  According to the manufacturing method of the present invention, the sealing operation can be performed even when at least one of the light-receiving surface side transparent plate 2 and the back plate 3 is curved. In this case, since a solar cell module sandwiched between bent glasses can be provided, it is possible to meet the demand for diversifying the design of buildings. Also, a bracket for fixing the module is provided, the bracket is inserted into a through-hole formed in either the light-receiving surface side transparent plate or the back plate, and the head side end of the bracket is on the sealing resin layer side The solar cell module which is arrange | positioned and the edge part on the opposite side of this metal fitting protrudes outside can also be provided. Thus, it is possible to provide a solar cell module applicable to the DPG method that has been widely used in recent years.

  In the solar cell module of the present invention, a plurality of solar cells 4 are regularly arranged between the light receiving surface side transparent plate 2 and the back plate 3 without being damaged. Since a large number of solar cells 4 can be sealed with resin without being damaged, a large-sized solar cell 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.

Example 1
As the solar cell 4, 40 square polycrystalline silicon solar 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 0.15 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.

  As the back plate 3, float plate tempered glass (blue plate glass) of 1000 mm × 1500 mm × 10 mm was used. The surface compressive stress of the tempered glass is 100 MPa. As the sealing resin sheet, “Solar Eva SC36” manufactured by Hi Sheet Industry Co., Ltd. having a thickness of 0.6 mm 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. Two sealing resin sheets 31 and 32 having a size of 1000 mm × 1500 mm were stacked on the back plate 3. The two sealing resin sheets 31 and 32 constitute a second sealing resin sheet 30 having a thickness of 1.2 mm.

  A plurality of solar cells 4 connected to each other in the manner described above were placed on the second sealing resin sheet 30 and aligned as shown in FIG. The width of the gap 9 between the adjacent solar cells 4 was set to 50 mm both vertically and horizontally. Moreover, the width of the marginal part 10 outside the solar battery cell 4 is 75 mm in the longitudinal direction (direction in which eight cells are arranged) and 87.5 mm in the width direction (direction in which five cells are arranged). did.

  Subsequently, as illustrated in FIG. 12, the sealing resin sheet piece 44 was disposed in the gap portion 9 between the solar cells 4, and the sealing resin sheet piece 45 was disposed in the blank portion 10. The width of the sealing resin sheet piece 44 was 40 mm, and the width of the sealing resin sheet piece 45 was 60 mm. The sealing resin sheet piece 44 was disposed at a position near the center between the adjacent solar battery cells 4 so as to hold the conductive wire 8. Thus, by arrange | positioning in the center vicinity position, the movement of resin at the time of fuse | melting can be decreased, and it can also prevent that the photovoltaic cell 4 or the conducting wire 8 is damaged. And it can also prevent that the photovoltaic cell 4 moves until it melts.

  Further, as shown in FIG. 13, the upper sealing resin sheet piece 46 was disposed so as to intersect the lower sealing resin sheet piece 44 in the gap 9 between the solar cells 4. The width of the upper sealing resin sheet piece 46 is 40 mm. In the blank portion 10, the upper sealing resin sheet piece 47 is disposed on the lower sealing resin sheet piece 45. The size of the upper sealing resin sheet piece 47 arranged at the side portion of the blank portion 10 is 60 mm × 125 mm, and the upper sealing resin sheet piece 48 is also arranged at the corner. The total thickness of the sealing resin sheet pieces at the intersecting portion is 1.2 mm, and a load from above and below can be supported at this portion. Since the sealing resin sheet pieces 47 and 48 on the upper side of the blank part 10 are intermittently arranged and there is a gap other than the intersection part, a passage for discharging the internal air can be secured, and air bubbles are prevented from remaining. can do.

  After the sealing resin sheet pieces 44 to 48 were arranged as described above, two sealing resin sheets 21 and 22 having a size of 1000 mm × 1500 mm were stacked thereon. The two sealing resin sheets 21 and 22 constitute a first sealing resin sheet 20 having a thickness of 1.2 mm. A float plate tempered glass (white plate glass) of 1000 mm × 1500 mm × 10 mm was placed thereon as the light receiving surface side transparent plate 2. The surface compressive stress of the tempered glass is 100 MPa.

  Sealing operation was performed using the laminated body 60 obtained in this way, and also using the sealing processing apparatus shown in FIG. First, the entire periphery of the outer edge of the laminate 60 was covered with a bleeder 62, put into a rubber bag as a sealing processing container 61, connected to a pipe 64, and put into an oven 63. At this time, as shown in FIG. 9, the airflow in the oven 63 was made parallel to the series direction of the solar cells 4 connected to each other.

  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 oven 63, and the pressure is a pressure measured by the pressure gauge 74. Note that Step 1 which is “the 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 flat tempered glass is used for both the light-receiving surface side transparent plate 2 and the back surface plate 3, step 1 is adopted. Even without this, 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 of less than 0.005 MPa was increased to 0.07 MPa over 90 minutes. The ratio of the pressure increase rate (MPa / min) to the temperature increase rate (° C./min) at this time 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 allow the crosslinking reaction to proceed. 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. In addition, the solar cells are regularly arranged, and the curvature of the solar cells 4 connected in series by the conductive wires 8 is within 2 mm.

Example 2
In Example 1, the sealing process was performed in the same manner as in Example 1 except that the direction of the laminate 60 was rotated by 90 degrees compared to that in Example 1. That is, as shown in FIG. 10, the air flow in the oven 63 is perpendicular to the series direction of the solar cells 4 connected to each other.

  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. However, the solar cells 4 connected in series with the conducting wire 8 were curved by about 10 to 20 mm as shown by the one-dot chain line in FIG.

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 53 Module mounting bracket 60 Laminate 61 Sealing container 63 Oven 66 Tank 67 Vacuum pump

The present invention relates to a method for manufacturing a solar cell module. In particular, the present invention relates to a method for manufacturing a solar cell module in which solar cells are sealed with resin between a light-receiving surface side transparent plate and a back plate.

The present invention has been made to solve such problems, and in a method for manufacturing a solar cell module in which solar cells are sealed with a resin, solar cell modules having various shapes and sizes can be easily used. It is an object of the present invention to provide a method for manufacturing a solar cell module that can be sealed with a simple operation and at low cost .

In the method for manufacturing a solar cell module, the solar cell is sealed with a resin between the light-receiving surface side transparent plate and the back plate.
A first sealing resin sheet that covers substantially the entire surface of the light receiving surface side transparent plate is disposed between the light receiving surface side transparent plate and the solar battery cell, and substantially the entire surface of the back surface plate is disposed between the back surface plate and the solar cell. A second sealing resin sheet is disposed so as to cover the gap between the solar cells or the outer margin of the solar cell, and the total thickness is less than the total value of the thickness of the solar cell and the thickness of the conductive wire. A plurality of sealing resin sheet pieces having a thickness of 2 mm or more are arranged, and at that time, the plurality of sealing resin sheet pieces are sandwiched between the first sealing resin sheet and the second sealing resin sheet. In addition, a laminate is produced so that a plurality of sealing resin sheet pieces are arranged at intervals in the horizontal direction ,
The laminated body is put in a sealing treatment container made of a gas-impermeable flexible sheet, and a plurality of sealing treatment containers containing the laminated body are introduced into an oven and arranged parallel to each other at intervals. ,
The inside of the sealing treatment container is depressurized so that the load from the front and back surfaces is not directly applied to the solar battery cell so that the sealing resin sheet piece receives the load between the light receiving surface side transparent plate and the back plate. By exhausting air from between the sealing resin sheet pieces and flowing the hot air in a direction parallel to the laminated body in the oven to melt the sealing resin by heating the laminated body, and subsequently cooling The problem is solved by providing a method for producing a solar cell module characterized by solidifying a sealing resin.

In the above method, it is a preferred embodiment that both the light-receiving surface side transparent plate and the back plate are glass plates. It is also a preferred embodiment that at least one of the light receiving surface side transparent plate and the back plate is curved. It is also a preferred embodiment that the laminate has a member protruding outward from the light-receiving surface side transparent plate or the back plate. At this time, it is preferable that the member protruding outward is a bracket for fixing the module. 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.

Claims (9)

In a method for manufacturing a solar cell module in which solar cells are sealed with resin between a light-receiving surface side transparent plate and a back plate;
A first sealing resin sheet that covers substantially the entire surface of the light receiving surface side transparent plate is disposed between the light receiving surface side transparent plate and the solar battery cell, and substantially the entire surface of the back surface plate is disposed between the back surface plate and the solar cell. A second encapsulating resin sheet covering the solar cell is arranged, and a sealing resin sheet piece thicker than the thickness of the solar cell is arranged in the gap between the solar cells or the outer margin of the solar cell to produce a laminate. And
The laminated body is put in a sealing treatment container made of a gas-impermeable flexible sheet, and a plurality of sealing treatment containers containing the laminated body are introduced into an oven and arranged parallel to each other at intervals. ,
The inside of the sealing treatment container is depressurized to discharge air between the light-receiving surface side transparent plate and the back plate, and the laminate is heated by flowing hot air in a direction parallel to the laminate in the oven. A method for producing a solar cell module, comprising melting the sealing resin and subsequently cooling the resin to solidify the sealing resin. The method for manufacturing a solar cell module according to claim 1, wherein the sealing treatment container is a bag made of a gas-impermeable flexible sheet. The manufacturing method of the solar cell module in any one of Claims 1-3 which heat a laminated body, maintaining the inside of the said oven at substantially atmospheric pressure. The manufacturing method of the solar cell module in any one of Claims 1-4 which arrange | position a some photovoltaic cell at intervals and are mutually connected by conducting wire. Each of the said sealing process container is connected to a vacuum pump via piping, and the manufacturing method of the solar cell module in any one of Claims 1-8 provided with a tank between a sealing process container and a vacuum pump. The method for manufacturing a solar cell module according to claim 9, further comprising a pressure gauge for measuring the pressure in the tank and a valve for introducing outside air into the tank, and finely adjusting the pressure in the tank. The method for producing a solar cell module according to any one of claims 1 to 12, wherein both the light-receiving surface side transparent plate and the back plate are glass plates. The method for manufacturing a solar cell module according to claim 1, wherein at least one of the light receiving surface side transparent plate and the back plate is curved. The method for producing a solar cell module according to any one of claims 1 to 16, wherein the sealing resin is made of a kind of resin selected from the group consisting of an ethylene-vinyl acetate copolymer, polyvinyl butyral, and polyurethane.

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