JP2014003170A - Sealing method of solar cell module and vacuum lamination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing method of a solar cell module capable of suppressing damage on the end of a glass substrate, even when a solar cell module is pressed directly by a diaphragm sheet in vacuum lamination.SOLUTION: In the sealing method of a solar cell module using a vacuum lamination device, a laminate laminating a glass substrate on which a thin film solar cell element is formed, a sealant film and a cover glass in this order is mounted on a mounting table of the device so that the cover glass becomes the upper surface, the laminate is pressed in the lamination direction by a diaphragm sheet, and an elastic sheet is provided on the surface of the mounting table for mounting the laminate. The vacuum lamination device includes a mounting table on which a laminate laminating a glass substrate having a thin film solar cell element formed therein, a sealant film and a cover glass is mounted, a diaphragm sheet for pressing the laminate in the lamination direction, and an elastic sheet provided on the surface of a mounting plate for mounting the laminate.

Description

  The present invention relates to a solar cell module sealing method, and more particularly to a technique for suppressing damage to a solar cell module when the module is pressure-bonded while being heated by a vacuum laminator.

  Solar cells are roughly classified into types such as single crystal solar cells such as silicon, polycrystalline solar cells, amorphous solar cells, and thin film solar cells. Among these, thin film type solar cells have the same output. Commercialization and development are being promoted because of the advantages that the amount of raw materials used is small compared to other solar cells, and the manufacturing process is simple and requires low energy.

Chalcopyrite type thin film solar cell is a kind of thin film solar cells, chalcopyrite compounds (for example _{Cu (In 1-x Ga x} ) Se 2, CIGS and abbreviated hereinafter) p-type light absorbing CIGS layer made of It consists of a substrate, a back electrode layer, a p-type light absorption layer, an n-type buffer layer, and a transparent electrode layer, and electricity is emitted from the back electrode layer and the transparent electrode layer by irradiating light. It can be taken out.

  3 and 4 show a plan view and a schematic cross-sectional view of a general chalcopyrite thin film solar cell provided with such a CIGS layer as a light absorption layer. In this battery, a back electrode layer 11 that functions as a positive electrode is formed on a substrate 10 by sputtering or the like. On the back electrode layer 11, a light absorption layer 12 containing Cu—In—Ga—Se (both the p-type light absorption layer and the n-type buffer layer are simply referred to as a light absorption layer) is formed. A transparent electrode layer 13 is formed on the substrate.

  In FIG. 3, the single cells 14 a to 14 g made of these layers are shown as the solar cell element 14. The solar cell element 14 includes a plurality of unit cells 14a to 14g separated by a rectangle, and each of the adjacent back electrode layers and transparent electrode layers (for example, the back electrode layer 11b and the transparent electrode layer 13a in FIG. 4). By being connected, they are connected in series.

  In the solar cell module, various sealing structures are known for protecting the solar cell element from moisture in the external environment. For example, the cover glass and the protective sheet obtained by laminating aluminum and a resin may be used. A solar cell sealing structure is known in which a solar cell element is sandwiched and the cover glass and the protective sheet are sealed with a sealing material made of ethylene-vinyl acetate copolymer (EVA) (for example, Patent Documents). 1).

  Such a solar cell module is manufactured by laminating a cover glass, a solar cell, and a protective sheet with a vacuum laminating apparatus.

  On the other hand, there is no backsheet as in Patent Document 1, the solar cell element is sealed with a cover glass and a glass substrate, and is housed in a frame, thereby improving the strength and durability against corrosion / deterioration from the outside. An improved type of solar cell module structure is also known (see, for example, Patent Document 2).

  The solar cell module using such a cover glass is superior in waterproofness as compared with the conventional one using a protective sheet, and the cost can be reduced because the protective sheet is not used.

  The solar cell module sealed with such a cover glass and a glass substrate is laminated by pressurizing with a vacuum laminating apparatus, as with a conventional solar cell module using a protective sheet, but protected with a conventional protective sheet and cover glass. There has been a problem that the glass substrate that has been subjected to pressure directly from the diaphragm sheet causes cracks at the peripheral edge of the glass substrate.

  This problem is shown in FIG. Conventionally, a solar cell module is disposed directly under the diaphragm sheet 40 via a protective sheet and is crimped. However, in a solar cell module having a structure in which a solar cell element is sandwiched between a cover glass and a glass substrate, FIG. As shown in FIG. 2, the cover glass 32 is disposed directly on the diaphragm sheet 40. When pressure is applied in this state, as shown in FIG. 2 (b), the pressure of the diaphragm sheet is directly applied to the cover glass 32. In particular, displacement at the end of the cover glass 32 is remarkable, In some cases, the pressure is transmitted to the glass substrate 10 having a low strength, and the end portion of the glass substrate 10 may be damaged without being able to withstand the load with the laminated hot plate 33.

  In particular, in a solar cell module of a type in which a through hole for wiring removal is provided at the end of the glass substrate, the strength of the end of the glass substrate is reduced due to the through hole, and the glass substrate is damaged during vacuum lamination. It was easy to get up and it was a problem.

JP 2001-53311 A JP 2009-188357 A

  The present invention has been made in view of the above situation, and sealing of a solar cell module capable of suppressing breakage of a glass substrate end even when the solar cell module is directly pressurized with a diaphragm in vacuum lamination. An object of the present invention is to provide a vacuum laminating apparatus used in the method and the sealing method.

  The present invention is a method for sealing a solar cell module using a vacuum laminating apparatus, wherein a laminated body in which a glass substrate on which a thin film solar cell element is formed, a sealing material film, and a cover glass are laminated in this order is used as a cover glass. It is placed on the mounting table of the apparatus so that the upper surface becomes the upper surface, the laminated body is pressed in the stacking direction with a diaphragm sheet, and an elastic sheet is provided on the surface of the mounting table on which the stacked body is mounted. It is a feature.

  Further, the vacuum laminating apparatus of the present invention includes a mounting table on which a laminated body in which a thin film solar cell element is formed, a sealing material film and a cover glass are laminated, and a diaphragm that pressurizes in the laminating direction of the laminated body. The sheet includes a sheet and an elastic sheet provided on a surface on which the stacked body of the mounting plate is mounted.

  In this invention, it is set as the preferable aspect that the said elastic sheet is a rubber sheet whose hardness is A50-70 in the sealing method and the vacuum laminating apparatus of the said solar cell module.

  According to the present invention, the elastic sheet is laid on the mounting table of the vacuum laminating apparatus, and the pressure is applied by the diaphragm sheet in a state where the glass substrate, the sealing material film, and the cover glass are laminated on the elastic sheet. Even when an excessive load is applied to the end portion of the glass substrate, the stress applied to the glass substrate is dispersed by the elastic sheet, and it is possible to prevent cracking of the glass substrate.

It is a schematic cross section which shows the sealing method of the solar cell module of this invention. It is a schematic cross section which shows the sealing method of the conventional solar cell module. An example of the thin film solar cell which can apply the sealing method of this invention is shown, (a) is a top view, (b) is sectional drawing. It is a partial expanded sectional view which shows typically the manufacturing method of a thin film solar cell. It is a schematic cross section which shows the vacuum laminating apparatus of this invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
The solar cell module structure to which the vacuum laminating apparatus of the present invention and the solar cell module sealing method using this apparatus can be applied is a chalcopyrite thin film solar cell or a single crystal / polycrystal / amorphous silicon solar cell. In general, the existing solar cells can be cited and are not limited.

  However, in a silicon solar cell, since the solar cell element (silicon cell) is manufactured separately from the substrate, the cell can be freely arranged on the substrate, and from the cell to the terminal box that penetrates the glass substrate. Since the wiring also has a high degree of freedom in handling, the location where the through hole is formed in the glass substrate can be determined freely.

  On the other hand, in the chalcopyrite thin film solar cell, since the solar cell element is directly formed on the glass substrate, the solar cell element cannot be separated from the substrate and rearranged, and wiring that penetrates the glass substrate is particularly difficult. . For this reason, the location where the through hole is formed is necessarily near the end of the glass substrate. Therefore, the vacuum laminating apparatus and the method for sealing a solar cell module of the present invention are suitably used for such a thin film solar cell in which the strength of the glass substrate end is lowered.

  FIG. 3A shows a plan view of a chalcopyrite thin film solar cell 1 to which such a drilling method of the present invention is preferably applied, and FIG. 3B shows a cross-sectional view thereof. FIG. 4 is a cross-sectional view of the chalcopyrite thin-film solar cell 1 and is a partial enlarged view (only the single cells 14a and 14b are shown) illustrating the manufacturing process of the thin-film solar cell 1. FIG.

  That is, as shown in FIGS. 4A to 4B, first, a back electrode layer 11 made of metal Mo or the like that functions as a positive electrode is formed on a substrate 10 made of soda lime glass (SLG) or the like, and a metal Mo target or the like. Is formed by sputtering or the like.

  As shown in FIG. 4 (c), the back electrode layer 11 has a scribe blade at the tip or is cut by a cutting means that performs cutting with a laser, and is divided into a plurality of separation grooves (to the back electrode layers 11a and 11b). Divided.

Next, as shown in FIG. 4D, a light absorption layer precursor made of Cu—In—Ga is formed on the back electrode layer 11 and in the separation groove, and then hydrogen selenide (H ₂ Se). ) A p-type light absorption layer made of CIGS is formed by performing a treatment for diffusing Se in the light absorption layer precursor by heat treatment in an atmosphere. Further, a buffer layer made of, for example, CdS, ZnS, or InS is formed on the light absorption layer by a chemical precipitation method (Chemical Bath Deposition method, CBD method). The p-type light absorption layer and the buffer layer serve as the light absorption layer 12.

  Next, as shown in FIG.4 (e), the light absorption layer 12 is divided | segmented into the several area | region (light absorption layer 12a and 12b) by the cutting means. As shown in FIG. 4F, a transparent electrode layer 13 made of ZnO, ZnAlO, or the like is formed on the light absorption layer 12 and in the separation groove.

  Finally, as shown in FIG. 4 (g), the transparent electrode layer 13 and the light absorbing layer 12 are cut together by a cutting means, and the transparent electrode layer 13 is divided into a plurality of regions (transparent electrode layers 13a and 13b). As shown in FIG. 3, the thin film solar cell 1 in which the solar cell elements 14 in which a plurality of vertically long rectangular unit cells 14 a to 14 g are connected in series in the horizontal direction of the drawing is formed on the glass substrate 10 is obtained.

  Although the thickness of the glass substrate 10 is in mm, the thickness of the solar cell element 14 is extremely thin, in μm units. However, in FIG. 4, the solar cell element 14 is enlarged in the thickness direction for explanation. And, it shows schematically.

  In FIG. 3, which is a plan view of the thin-film solar cell 1 obtained as described above, reference numeral 20a is a through hole through which the wiring 21a from the positive electrode current collector (not shown) passes outside the solar cell. In FIG. 3, the back electrode layer 11 a of the leftmost cell 14 a is connected to a positive electrode current collector, and the positive electrode current collector has a wiring 21 a made of glass via a through hole 20 a formed in the glass substrate 10. The wiring 21a is led out to the back side of the substrate 10 and taken out from a wiring box (not shown).

  Similarly, the transparent electrode layer (not shown in FIG. 4) of the rightmost unit cell 14g is connected to a negative electrode current collector (not shown), and the negative electrode current collector passes through the glass substrate 10. The wiring 21b is led out to the back side of the glass substrate 10 through the hole 20b, and the wiring 21b is taken out from a wiring box (not shown).

  Since the end portions of the glass substrate 10 are reduced in strength due to the formation of these through holes 20a and 20b, the vacuum laminating apparatus of the present invention described later and a sealing method using the same are used.

  First, the sheet of the sealing material 30 and the end sealing material 31 and the cover glass 32 are placed on the solar cell element 14 side of the thin film solar cell 1 obtained as described above, and in the vacuum laminating apparatus. Crimp while heating under vacuum.

  As the vacuum laminating apparatus used in the present invention, a known apparatus such as a double vacuum laminating apparatus can be used. Such a vacuum laminating apparatus of the present invention is shown in FIG. As shown in FIG. 5, the vacuum laminating apparatus 4 includes a lower chamber 42 and an upper chamber 41 that is opened and closed with respect to the lower chamber 42 by a driving unit (not shown).

  The upper chamber 41 is provided with a diaphragm sheet 40 whose peripheral portion is hermetically fixed to the inner wall of the upper chamber 41. Further, a mounting table 43 on which the solar cell module is mounted is provided in the lower chamber 42, and a heater for heating at the time of thermocompression bonding is built therein.

  One side wall of the upper chamber 41 is provided with an upper air supply / exhaust hole 44 that communicates with a space isolated by the diaphragm sheet 40, and an air supply / exhaust pump (not shown) is connected to the upper air supply / exhaust hole 44. Similarly, a lower air supply / exhaust hole 45 is provided in one side wall of the lower chamber 42, and another air supply / exhaust pump (not shown) is connected to the lower air supply / exhaust hole 45.

  In order to seal the thin film solar cell 1 as a module using the vacuum laminating apparatus 4, first, as shown in FIG. 5, if necessary, a laminating hot plate 33 is placed on the mounting table 43 of the lower chamber 42. Then, the elastic sheet 50 is laid. Subsequently, the glass substrate 10 is placed in contact with the elastic sheet 50. Subsequently, the thin-film solar cell 1 is configured so that the glass substrate 10, the solar cell element 14, the sealing material 30, and the cover glass 32 are arranged in this order from the bottom.

  Subsequently, the upper chamber 41 is closed with respect to the lower chamber 42, and the supply / exhaust pump is operated to decompress the upper chamber 41 and the lower chamber 42, and then the decompressed state of the upper chamber 41 is released. Then, as shown in FIG. 1, the diaphragm sheet 40 provided in the upper chamber 41 expands downward, and is pressed against the thin-film solar cell 1 placed on the placement table 43 heated by the heater. Thus, the thin-film solar cell 1 is heat-pressed by the mounting table 43 (elastic sheet 50) and the diaphragm sheet 40, and the sealing material 30 and the end sealing material 31 are softened and melted, and the cover glass 32 and the solar cell element 14 Adhesion with and form a laminate.

  At this time, in the conventional vacuum laminating apparatus, as shown in FIG. 2, since the cover glass 32 is arranged directly on the diaphragm sheet 40, the pressure of the diaphragm sheet is directly applied to the cover glass 32. The end portion of the glass substrate 10 may be damaged without being able to withstand the load between the laminated hot plate 33 and the glass substrate 10 having low strength at the end portion.

  On the other hand, in the present invention, as shown in FIG. 1, even if the end portion of the glass substrate 10 is pressed by the diaphragm sheet 40, the end portion of the glass substrate 10 is sunk into the elastic sheet 50. The stress concentrated on the end portion of 10 is dispersed, and breakage can be prevented.

  After the thermocompression bonding is completed in this manner, the thin film solar cell module 1 is taken out from the vacuum laminator 4. To perform this removal, the decompression state of the lower chamber 42 is released, the diaphragm sheet 40 expanded downward is contracted to the original state, the upper chamber 41 is raised, and the vacuum laminating apparatus 4 is opened. It can be carried out.

  In addition, although the conditions of the thermocompression bonding using the vacuum laminating apparatus 4 can be suitably set according to the curing characteristics of the resin of the sealing material to be used, in the case of EVA blended with a normal organic peroxide, 120 ° C. to 130 ° C. A temperature of 10 minutes is sufficient for 10 minutes.

  The elastic sheet used in the present invention can be a rubber sheet having a hardness of A50 to 70, and examples of such a sheet include silicon rubber, fluorine rubber, ethylene / propylene rubber, etc. It is preferable to use rubber.

  The sealing material and the end sealing material used in the present invention are resins that can be cured through heating and softening and melting, and seal the solar cell element 14 formed on the glass substrate 10 to be strong. It is a resin that can be bonded. Examples of such resins include thermoplastic resins such as ethylene / vinyl acetate copolymer (EVA), ethylene / vinyl acetate / triallyl isocyanurate (EVAT), polyvinyl butyral (PVB), and polyisobutylene (PIB). EVA is particularly preferable from the viewpoint of adhesion to the glass substrate 10 and cost.

  These thermoplastic resins are preferably blended with a curing agent in order to crosslink and cure them. Examples of such curing agents include organic peroxides such as 2,5-dimethylhexane-2,5-dihydroperoxide. Oxides are preferred.

  It is promising for the production of thin-film solar cells with low strength against pressure bonding, as well as silicon-based solar cells.

1. Thin film solar cell
10 ... substrate,
11 ... back electrode layer,
11a, 11b ... divided back electrode layers,
12 ... light absorption layer,
12a, 12b ... divided light absorption layers,
13 ... Transparent electrode layer,
13a, 13b ... divided transparent electrode layers,
14 ... solar cell element,
14a-14g ... single cell,
20a, 20b ... through holes,
21a, 21b ... wiring,
30: Sealing material,
31 ... End sealant,
32 ... cover glass,
33 ... Laminated hot plate,
4 ... Vacuum laminator,
40 ... Diaphragm sheet,
41 ... upper chamber,
42 ... lower chamber,
43 ... mounting table,
44 ... upper chamber air supply / exhaust hole,
45 ... Lower chamber air supply / exhaust hole,
50: Elastic sheet.

Claims (4)

A method for sealing a solar cell module using a vacuum laminator,
A laminated body in which a glass substrate on which a thin-film solar cell element is formed, a sealing material film, and a cover glass are laminated in this order is placed on a placing table of the apparatus so that the cover glass is on the upper surface,
Pressurizing the laminate in the direction of lamination with a diaphragm sheet,
A sealing method for a solar cell module, wherein an elastic sheet is provided on a surface of the mounting table on which the stacked body is placed.   The method for sealing a solar cell module according to claim 1, wherein the elastic sheet is a rubber sheet having a hardness of A50 to 70. A mounting table on which a laminated body in which a glass substrate on which a thin-film solar cell element is formed, a sealing material film, and a cover glass are stacked;
A diaphragm sheet that pressurizes in the stacking direction of the laminate,
The vacuum laminating apparatus provided with the elastic sheet provided in the surface which mounts the said laminated body of the said mounting plate. The vacuum laminating apparatus according to claim 3, wherein the elastic sheet is a rubber sheet having a hardness of A50 to 70.

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