JP2009099883A - Thin film solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin film solar cell module capable of advancing its reliability by improving an electrochemical corrosion. <P>SOLUTION: In this structure, the thin film solar cell module is formed on one side of a translucent glass substrate 1, a transparent surface plate 22 is adhered to another side of the translucent glass substrate 1 through a first adhesive agent 21, and a back plate 24 is adhered to the one side through a second adhesive agent 23. A third adhesive agent 25 covers a whole periphery of the side surface of the translucent glass substrate 1, thereby the adhesive agent covers all sides including side surfaces of the transparent substrate to form a structure in which the continuous adhesive agent covers the translucent glass substrate 1, and to prevent moisture from entering the structure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a structure with improved reliability of a thin-film solar cell module, and more particularly to a technique for suppressing electrochemical corrosion due to moisture erosion.

Photovoltaic power generation is used as an environment-friendly energy source with little generation of CO ₂ , and in particular, thin film solar cell modules are attracting attention because they consume less energy for production and raw material resources.

  The solar cell module is assumed to be used outdoors, and is used continuously for a long period of, for example, 20 years after installation. In addition, various environments such as extremely cold regions, tropical regions, and deserts are assumed as installation locations. For this reason, the solar cell module is required to have extremely strict weather resistance specifications.

  Crystalline solar cell modules have been used for more than 20 years and have been confirmed to be reliable enough for practical use, but thin-film solar cell modules have a track record of about 15 years. In the power generation test plant where the module is installed, there are practically no problems, but some reliability problems remain.

As a typical problem, Non-Patent Document 1 discloses that although there is no practical problem in a solar cell module, electrochemical corrosion is observed. A thin-film solar cell module has a device structure in which a transparent electrode layer such as tin oxide (SnO ₂ ) is formed on a glass substrate having the size of the solar cell module, and a transparent semiconductor layer and a back electrode layer are laminated. These films are accumulated by patterning with laser scribing etc. so that small solar cells are connected in series or in series-parallel connection, and these solar cells are placed on the back layer of a filler such as EVA. It has a structure in which a terminal box or a frame is attached to another glass plate or one sealed with a single-layer or multi-layer film. Further, a peripheral edge exposed portion is provided by removing all the films forming cells in a specific width region from the end face of the glass substrate with a polishing wheel or sandblast.

  According to this document, the corrosion usually occurs from the lower end of the frame on the lower side of the thin-film solar cell module installed at an inclination, and is related to the ingress of moisture into the module. This corrosion also depends on the voltage applied to the module and has been shown to result in the disappearance or delamination of the cell structure from the glass surface.

  In Patent Document 1, at least a part of a transparent electrode layer, an optical semiconductor layer, and a metal layer formed on a light-transmitting substrate is separated into a plurality of cells by processing with a light beam and electrically integrated with each other. A thin film solar cell module, wherein the optical semiconductor layer and the metal layer at the peripheral edge of the translucent substrate are removed mechanically or with a light beam. Is disclosed. Patent Document 1 discloses that a thin-film solar cell module having excellent withstand voltage characteristics can be obtained with a high yield by an extremely simple process. However, even Patent Document 1 recognizes that further problems remain.

Patent Documents 2 and 3 disclose techniques for superposing and bonding tempered glass on the light incident side of a glass substrate.

Japanese Patent Laid-Open No. 2000-261019 JP 2003-110128 A JP 2001-085726 A D. Carlson et al., Proc. NCPV and Solar Program Meeting 2003 pp 946-949, NREL / CD-520-33586

  In the thin film solar cell module as disclosed in Patent Document 1, the phenomenon observed by the inventors in a specific case where there is a usage condition is also somewhat similar to the phenomenon estimated in Non-Patent Document 1 in principle. It seems to be a phenomenon. That is, moisture remaining on the frame or the like is dampened either in the filler itself between the glass substrate on which the solar cells are formed and the glass or film on the back surface layer or in the gap between the glass substrate and the filler. Is estimated to have invaded. It is estimated that the moisture may reach the cell region via the peripheral edge exposed portion and an electrochemical reaction may have occurred in that portion.

  Further, as an improved structure of the solar cell module described here, Patent Document 1 discloses a technique in which the peripheral edge exposed portion is polished and laser scribing is used in combination, but the electrochemical corrosion described here may be delayed. Although it is possible, the effect is slight, and there are still problems regarding the suppression of the period of several times.

  On the other hand, in a thin film solar cell module, it is difficult to use tempered glass as a material for a glass substrate on which elements are formed. The reason is that when a transparent electrode is formed on glass, a high temperature of about 600 ° C. is required, and when tempered glass is exposed to this temperature, it is annealed to normal glass.

  As one proposal for this measure, as in Patent Documents 2 and 3, a technique for superposing and bonding tempered glass on the light incident side of a glass substrate has been developed.

  Here, when the crystalline solar cell module shown in FIG. 5 is compared with the conventional thin film solar cell module shown in FIG. 4, in the thin film solar cell module, only one surface of the substrate on which the solar cell elements are formed is covered with resin. On the other hand, in the case of a crystalline solar cell module, the filler (adhesive) is in close contact with all surfaces including the side surface of the substrate on which the solar cell element is formed, and is encapsulated in resin. I understand. The glass exhibits conductivity when it contains moisture, but the filler maintains insulation even when it contains moisture. If this principle can be utilized in a module that uses, the reliability is expected to be greatly improved.

  However, Patent Documents 2 and 3 do not seem to use this principle. Although Patent Document 2 succeeds in suppressing the strength and reflection of the glass on the surface side, the end portion of the glass substrate is exposed to the atmosphere. Patent Document 3 includes an example in which all surfaces of the glass of the substrate are covered with an adhesive (EVA), but there is no contrivance so that there is no gap in the EVA, and it is provided in the periphery. The surroundings are protected by a sealing agent such as silicone, and the solar cell element substrate cannot be sealed and continuously sealed unlike a crystalline solar cell.

  As described above, the conventional thin-film solar cell module may be inferior in electrochemical corrosion resistance as compared with the crystalline solar cell module. The present invention solves this problem.

The first of the present invention is
From the light incident side, a configuration in which the transparent front plate, the first adhesive, the translucent glass substrate, the transparent electrode layer, the optical semiconductor, the back electrode layer, the second adhesive, and the back plate are arranged. A thin film solar cell module comprising:
A solar cell is formed by sequentially laminating a transparent electrode layer, an optical semiconductor layer, and a back electrode layer from the light incident side on the surface far from the light incident side of the translucent glass substrate,
A transparent surface plate is bonded via a first adhesive on the light incident side of the translucent glass substrate,
A photovoltaic cell is formed on a surface far from the light incident side of the light transmissive glass substrate, and a back surface of the light transmissive glass substrate far from the light incident side is interposed through a second adhesive. A thin-film solar cell module including a structure in which plates are bonded,
The side surface of the translucent glass substrate is covered with a third adhesive all around,
All the surfaces including the side surface of the translucent glass substrate are covered with the adhesive layer,
The first adhesive, the second adhesive, and the third adhesive are the same adhesive, and the adhesive is continuous at least on the side surface of the translucent glass substrate. Battery module.

In the present invention, the size of the transparent front plate and the size of the back plate are
The size of the translucent glass substrate and the thickness of the third adhesive provided on the side surface,
A thin film solar cell module characterized by being the same or larger.

  This configuration protects the continuous adhesive layer. The present invention is also a thin-film solar cell module, wherein the transparent surface plate described above is tempered glass.

  A resin film can be used for the transparent surface plate, but the use of tempered glass can further impart strength to the thin-film solar cell module.

  According to the present invention, the reliability of a solar cell using a translucent glass substrate, in particular, the reliability related to the penetration of moisture from the edge of the substrate represented by the electrochemical corrosion phenomenon is greatly improved. It has become possible to provide modules in an inexpensive and industrially efficient way.

  In addition, when the configuration of the present invention is combined with a conventional technology, a configuration of a thin-film solar cell module in which tempered glass is provided on the light incident side, or a technology in which a film having a design property is attached to the surface, It is possible to drastically improve the weather resistance in actual use without adding any member or process while taking advantage of the strength improvement and anti-glare effect that are characteristic of the above.

  A specific configuration of the present invention will be described.

In the thin film solar cell module of the present invention, as the translucent glass substrate, those generally used for thin film solar cell modules such as blue plate glass, white plate glass and borosilicate glass are used. When using glass that contains impurities such as sodium and blue that contain semiconductors that affect semiconductors, an alkali barrier layer such as silicon oxide (SiO ₂ ) is used on one side to prevent diffusion of these impurities. In some cases, an underlayer such as silica beads may be provided to facilitate light scattering of the transparent electrode layer, and these can also be suitably used.

A transparent electrode layer is formed on one side of the translucent glass substrate. As the transparent electrode layer, tin oxide (SnO ₂ ), zinc oxide (ZnO), ITO, or the like can be used.

  As the optical semiconductor layer, a layer containing silicon as a main component, for example, a stacked structure of a p-type a-SiC: H layer, an i-type a-Si: H layer, and an n-type microcrystalline Si: H layer can be used. . In recent years, solar cells using an i-type microcrystalline Si layer as a power generation layer, tandem solar cells in which a-Si and microcrystalline Si solar cells are stacked, and compound semiconductors such as CIS, CdTe, CIGS, etc. Have been developed, and the present invention can also be used for thin-film solar cells using these.

  As the metal layer, Ag, Al, Cr, Ti, a laminate of these and a metal oxide, or the like can be used. As a metal oxide, zinc oxide (ZnO) or the like is effective, but not limited thereto.

  These layers are processed by a method such as laser scribing and integrated with a well-known structure. The transparent electrode layer, the optical semiconductor layer, the back electrode layer, and the integrated solar cell group have areas for forming wiring for taking out electrodes at both ends, and the solder-plated copper foil is connected by special solder. The

  The peripheral edge mechanical etching is performed by a surface polishing method or sand plast. The surface polishing method is performed using a polishing wheel in which an abrasive is fixed to a metal rotating disk or a hard metal surface processed. By moving the end of the grinding wheel along the peripheral edge, a belt-like peripheral exposed portion can be formed. Sand blasting is performed by spraying fine particles from a nozzle. The material of the fine particles is glass beads, alumina ceramic, and the like, and there are various particle sizes, and can be appropriately selected according to a predetermined processing degree. In this case, the processed surface is polished glass, and fine irregularities are formed on the surface.

  Further, the width of the exposed peripheral portion is appropriately designed, but in the case of conforming to IEC 61730, which is a safety standard for solar cells, a 600V-specific solar cell module needs to have a width of 6.4 mm or more. These widths may be appropriately selected in consideration of various standards such as the ratio of the area necessary for the output of the solar battery cell to the translucent glass substrate, the distance necessary for preventing electrochemical corrosion, in addition to the industrial standards. Is possible.

  Through the above steps, the solar cell element is formed on the light-transmitting glass substrate to become a solar cell element substrate.

  The light incident side surface (the other surface) of the translucent glass substrate and the transparent surface plate are bonded with a first adhesive.

  The transparent surface plate serves to protect the first adhesive and the third adhesive from mechanical impacts such as ultraviolet rays and scratches, or to improve the mechanical strength of the entire thin-film solar cell module as an additional function. .

  As a material in the case of paying attention to the former function, a cover film for solar cells that has been used for protecting the light incident side in the prior art or a combination of the film and a strength improving material such as a glass nonwoven fabric is used. Examples of specific materials include ETFE (tetrafluoroethylene / ethylene copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), PCTFE (polychlorofluoroethylene), PTFE (polytetrafluoroethylene). PET (polyethylene terephthalate) blended with an ultraviolet light agent is preferably used.

  As a material in the case of paying attention to the latter function, tempered glass, polycarbonate, or the like used in a conventional solar cell module of polycrystalline silicon or single crystal silicon is used.

  A back plate is bonded to one surface of the translucent glass substrate on which the solar cell element is formed by a second adhesive. Actually, in order to take out the electric power generated by the formed solar cell element, the copper foil ribbon (lead) is insulated from the opening provided in the back plate by insulating with another adhesive or insulating film. The back plate is bonded while being arranged to take out the foil lead. As a wiring arrangement method, a conventional sealing technique can be used, and a method described in, for example, Japanese Patent Application Laid-Open No. 2000-077383 is appropriately used as a subsequent sealing process.

  The back plate plays a role of protecting the second adhesive and the solar cell element from mechanical shocks and moisture. As the material for this portion, those used as the back cover film in the prior art are preferably used. Examples include a PET / Al foil / PVE (polyvinyl fluoride) three-layer film, a film laminated with a transparent surface plate, an Al foil, or a glass plate, which is appropriately selected and used. .

  As 1st, 2nd, and 3rd adhesive agents, it can select suitably from what is called the filler used by the conventional solar cell. Silicone as a liquid type filler, EVA (ethylene, vinyl acetate copolymer) as a filler that is supplied in the form of a sheet and heated and cured, or thermoplastic ionomer (commercial product example: DuPont Surlyn) These can be used as adhesives. Each can be composed of different materials, but when the first, second, and third adhesives are made of the same material and melted and solidified in a single process, the three parts are completely integrated. It becomes possible to encapsulate the translucent glass substrate and the solar cell element formed on one side thereof with a completely seamless adhesive layer. In this way, the laminate part is configured.

  In practice, the first, second and third adhesives, transparent surface plate, solar cell element substrate, back plate, interconnect material for wiring and insulating spacers to prevent contact with those elements are once May be difficult to incorporate into In that case, for example, a vacuum plate laminator set to a temperature at which the front plate, first adhesive, third adhesive, and translucent glass substrate (solar cell element substrate) are incorporated and the resin can only be melted. It is also possible to laminate the material and temporarily fix them, then add and assemble other members, melt the resin again with a vacuum laminator, and process at the temperature to crosslink the whole to configure the laminated part .

  A thin film solar cell module is completed by attaching a terminal box to the laminate part assembled in the above process, applying butyl rubber to the end part of the laminate, fitting a gasket such as EPDM, and attaching an aluminum frame.

  In the above description, a case where only one solar cell element substrate in which a solar cell element is formed on a translucent glass substrate is attached to a translucent front plate is described. It is also possible to place a plurality of solar cell element substrates. In this case, the transmissive glass is preferably tempered glass. There are various types of tempered glass, but low-iron plate tempered glass having unevenness on both sides is sold as a general-purpose solar cell cover glass for crystalline solar cells, so that it is appropriately used. In addition, in order to implement | achieve the thin film solar cell module containing the structure of invention of this application, it is desirable to manufacture on the following conditions at the time of manufacture. For example, when EVA is used as an adhesive, the entire structure is assembled and then the resin is melted and thermally crosslinked, or melted at a temperature at which the resin does not crosslink and partially assembled, and finally the whole is melted. It is desirable from the viewpoint of production to cause crosslinking. It is known that even if another resin of the same type is overlapped and melted once on a cured resin, an interface is formed at that portion. Since this interface also causes a continuous minute gap, such as a weld line that occurs in plastic injection molding, the first adhesive, the second adhesive, and the third adhesive are bonded in manufacturing. It is necessary to create a situation where both melt at the interface between the agent layers, which is a manufacturing point. If it does so, it will be in the state enclosed in the bag of the adhesive agent hardened | cured in the side surface of the solar cell element board | substrate which is especially easy to generate | occur | produce, and reliability can be ensured.

  In addition, the argument that the present application is difficult to conceive from the prior art will be described below.

  Certainly, in order to improve the reliability of the thin film solar cell module, when the solar cell element substrate is encapsulated with the resin layer of the filler as in the crystalline solar cell module, the electrochemical corrosion resistance equivalent to that of the crystalline solar cell module is achieved. Is expected to be obtained. However, a person skilled in the art, according to the background described below, seems to have required less for a thin film solar cell module.

  As a conventional technique, a crystalline solar battery has a structure in which crystalline silicon cells are buried in a filler (adhesive). The reason for this is, of course, that the crystalline silicon cell itself is a semiconductor and is extremely vulnerable to contamination around it. The same applies to solar cells formed on metal plates, which must be enclosed in resin.

  On the other hand, solar cells using glass are said to be protected against surrounding dirt if at least the surface on which the elements are formed is sealed. Many current solar cells are the idea, and reliability has been improved by sealing the edge of the substrate with butyl rubber. In the solar cells of Patent Documents 2 and 3, it is considered within that range.

  However, blue plate glass and low iron float glass, which are used as substrates for solar cells that use glass, contain ions inside, and are known to become conductors to some extent, especially at high temperatures. This can be inferred from seasonal variations in an insulation test in which the solar cell module is submerged in the shipping inspection to check the insulation. There is a possibility that this fact was not noticed by conventional technology, or it was difficult to detect.

  From the viewpoint of further improving the reliability, the inventors have realized that a structure of a solar cell module that takes into consideration “a certain degree of conductivity of glass” that could not be conceived by those skilled in the art is required. .

  EVA maintains high resistance in the range of operating temperature and humidity, and continues to be an insulator. Moreover, it has a track record as a sealing material for several decades. It is thought that covering the entire solar cell substrate with such a high resistance material will ensure the insulation of the element part and cut off the moisture ingress path. The present invention has been achieved as something that can be realized by slightly improving the structure.

  The present application provides a means for realizing the solution to this problem, and as a result, improves the reliability of the thin film solar cell module.

  In addition, in the conventional thin-film solar cell module, the reason why the three light-transmitting plates were not used was that the terminal extraction of the positive electrode and the negative electrode became complicated, and there were obstructive factors such as structural difficulties. Estimated. A “crystalline” solar cell, which is a prior art, has a structure in which a plurality of cells of crystalline silicon are buried in a filler (adhesive). Therefore, from the viewpoint that a plurality of cells exist in the horizontal direction, it seems that the terminal extraction of the positive electrode and the negative electrode also tends to be in the horizontal direction. Therefore, a shape using three glass plates was easy.

  On the other hand, in the conventional “thin film” solar cell module, the reason why the three light-transmitting plates were not used was that it was difficult to take out the terminals of the positive electrode and the negative electrode, and there were obstacles such as structural difficulties. Both are estimated.

That is, in the thin film solar cell module, the positive and negative terminals can be easily taken out in the vertical direction of the substrate and the like. Therefore, in the configuration of the present invention using the three-sheet glass, it is complicated to take out the terminals of the positive electrode and the negative electrode, and there are obstructive factors that are difficult in structure. Are not easily conceived by those skilled in the art.

  Hereinafter, various examples according to the embodiment of the present invention will be described.

Example 1
FIG. 1 is a cross-sectional view showing a thin film solar cell module according to an embodiment of the present invention.

  In each drawing of the present application, the dimensional relationship is appropriately changed for clarity and simplification of the drawings and does not reflect the actual dimensional relationship. On the other hand, the same reference numerals are used unless otherwise specified. It represents the same part.

The solar cell module shown in FIG. 1 is manufactured as follows. First, silicon oxide (SiO _{2) is formed} on a light-transmitting glass substrate 1 made of low iron soda-lime glass having an area of 91.5 cm × 45.5 cm and a thickness of 4 mm (the thickness of the light-transmitting glass substrate is 4 mm) by a thermal CVD method. ) Barrier layer (thickness 1000 mm) and a tin oxide layer (thickness 8000 mm). In order to integrate a plurality of cells, this tin oxide layer was patterned by laser scribing to form a transparent electrode 2. Reference numeral 3 indicates a transparent electrode scribe line.

  In addition, in order to electrically isolate the peripheral part (peripheral part) and the solar cell active part over the entire circumference at a position of 5 mm from the periphery of the substrate, as shown in FIG. Then, patterning was performed by laser scribing. Reference numeral 13 denotes a laser insulation separation line formed thereby.

  As a patterning method, the substrate 1 was set on an XY table, and separation processing was performed using a Q-switched YAG laser. The operating conditions of the laser were a second harmonic of 532 nm, a pulse width of 3 kHz, an average output of 500 mw, and a pulse width of 10 nsec. The separation width is 50 μm, and the width of the string (individual solar cell) is about 10 mm.

Moreover, the area | region 8 for forming the wiring for electrode extraction using solder plating copper foil was left with the width | variety of 3.5 mm on the outer side of the strings 11a and 11b in both ends.
On the tin oxide film 2 thus patterned, an a-Si layer 4 was formed by a plasma CVD method in a plasma CVD chamber of a separation type apparatus. That is, at 200 ° C., a p-type a-SiC: H semiconductor layer, an i-type a-Si: H semiconductor layer, and an n-type microcrystalline Si: H semiconductor layer are sequentially deposited to form a laminated a- Si layer 4 was formed. In order to form each layer, silane (SiH ₄ ) having a flow rate of 100 sccm, 500 sccm, and 100 sccm, respectively, is used. When forming a p-type semiconductor layer and an n-type semiconductor layer, B ₂ H ₆ diluted to 1000 ppm with hydrogen is used. And PH ₃ were mixed at 2000 sccm.

In addition, the p-type semiconductor layer was formed by carbon alloying by mixing 30 sccm of CH ₄ . The input power for forming each layer was 200 W, 500 W, and 3 kW, respectively, and the reaction pressure was 1 torr, 0.5 torr, and 1 torr, respectively. The film thicknesses of the formed layers are estimated to be 150 mm, 3200 mm, and 300 mm, respectively, from the film forming time.
After forming each layer of the optical semiconductor in this way, the substrate 1 is set on an XY table, and the a-Si layer 4 is moved from the patterning position of the SnO2 layer 2 using a Q-switched YAG laser. Patterning was performed by shifting to the left by 100 μm. The operating conditions of the laser are the second harmonic 532 nm, the pulse width 3 kHz, and the average output 500 m.
w, pulse width 10 nsec. The separation width was set to 100 μm by shifting the focal position. Reference numeral 5 indicates a semiconductor scribe line.

  Thereafter, a ZnO layer (not shown) having a thickness of 1000 mm was formed on the patterned a-Si layer 4 by a magnetron sputtering method using a zinc oxide (ZnO) target by RF discharge. The sputtering conditions were an argon gas pressure of 2 mtorr, a discharge power of 200 W, and a film forming temperature of 200 ° C.

  Next, a back electrode layer 6 having a thickness of 2000 mm was formed on the ZnO layer by direct current discharge and room temperature by using an Ag target of the same magnetron sputtering apparatus. The sputtering conditions were an argon gas pressure of 2 mtorr and a discharge power of 200 W.

  Finally, the substrate 1 is taken out from the magnetron sputtering apparatus, set on the XY table, the Ag layer and the a-Si layer 4 are patterned using the Q-switched YAG laser, and the semiconductor scribe line 5 is used. A back electrode scribe line 7 was formed at a position separated by 100 μm. The operating conditions of the laser were exactly the same as the processing conditions for the a-Si layer 4. The separation width is 70 μm and the string width is about 10 mm.

  Further, as in the case of the tin oxide film 2, in order to electrically separate the peripheral portion (peripheral portion) and the solar cell active portion over the entire circumference at a position of 5 mm from the periphery of the substrate, In addition, patterning by laser was performed. The division width was 150 μm, and the separation part 13 of the tin oxide film 2 was processed.

  Next, a further outer portion of 0.5 mm outside this patterning line was polished over the entire circumference with a polishing width of 7 mm and a depth of about 2 μm using a sand blasting apparatus. That is, the entire thickness of the metal electrode layer 6, the zinc oxide (ZnO) layer, the a-Si layer 4 and the tin oxide film 2 is removed, and the surface portion of the glass substrate 1 is removed to form the peripheral exposed portion 9. A solar cell element substrate was formed.

  Thereafter, the bus bar electrode 10 made of solder-plated copper foil was soldered to the position 8 for bus bar wiring with a special solder 14, and wiring for electrode extraction was performed. The electrode 10 is parallel to the string.

  PTFE (polytetrafluoroethylene) film (trade name: DuPont Teflon FEP Film) whose adhesiveness was improved as the transparent surface plate 22 on the surface of the light-transmitting glass substrate on which no element was formed (surface on the light incident side) ) Was attached using EVA as the first adhesive 21. In this case, the thickness of PTFE is 300 μm (the thickness of the transparent surface plate is 300 μm), and the size is 92 cm × 46 cm. The size of EVA is 92 cm × 46 cm, which is the same as the size of PTFE, and the thickness is 600 μm (the thickness of the first adhesive is 600 μm). At this time, a strip-shaped EVA sheet having a width of 10 mm is disposed on the inner side along the EVA side of the first adhesive so that the amount of EVA disposed around the edge of the transparent surface plate is increased. . They were arranged evenly around the translucent glass substrate so that a width of 2 mm or more was secured, and they were bonded together with a vacuum laminator at a setting of 120 ° C. for 10 minutes. By doing so, a part of the third adhesive 25 disposed on the side surface of the translucent glass substrate is filled. In order to maintain the thickness of the adhesive and the purpose of placing the substrate accurately, vacuum lamination is performed with a PTFE frame (trade name: DuPont Teflon) that has undergone releasability processing with the size of the PTFE film as the inner layer. Processing. The thickness of the frame was set to 4.9 mm (4 mm + 600 μm + 300 μm), which is the total thickness of the transparent surface plate, the first adhesive, and the translucent glass substrate.

  Next, on the element surface side of the translucent glass substrate 1, an EVA sheet 23 as a second adhesive and a PVF / Al / PET as a back plate 24 are covered and sealed with a vacuum laminator, and a terminal box is attached. It is a process. The PET surface is bonded to EVA. Similarly, a strip-shaped EVA sheet having a width of 10 mm was placed on the periphery of the translucent glass substrate. In terms of design, the second half of the third adhesive 25 provided on the side surface of the substrate 1 is formed. Since it is difficult to place the adhesive in a very narrow area, a strip-shaped EVA is attached around the glass substrate and melted in the laminating process to fill the area shown in FIG. 25 and achieve the same effect. Aiming to get.

  The EVA sheet 23 was placed thereon, and the back plate 24 was stacked in this order. The size of the back plate 24 is 92 cm × 46 cm, which is the same as that of the transparent front plate, and alignment is performed so that the sides overlap so as to be the same position. Again, the steps of melting, vacuum defoaming, pressing, and crosslinking were performed in a vacuum laminator under the conditions of 150 ° C. for 30 minutes to complete the sealing process. Here, the thickness of EVA is 600 μm (the thickness of the second adhesive is 600 μm). Here, a vacuum laminating process is performed in a state in which a PTFE frame (trade name: DuPont Teflon, DuPont Teflon) (back plate thickness: 300 μm) that has been subjected to releasability processing with the size of the PTFE film as an inner part is installed. The thickness of the frame is that of the transparent front plate (thickness 300 μm), the first adhesive (thickness 600 μm), the translucent glass substrate (thickness 4 mm), the second adhesive (thickness 600 μm), and the back plate (thickness 300 μm). It was set to 5.8 mm which is the total thickness in design.

  Thus, the structure shown in FIGS. 1 and 2 was completed through two vacuum laminating steps. Of course, it can be completed by a single laminating process. However, in order to facilitate alignment, this process is performed.

  Lead wires were raised from holes provided in the back plate 24, and cables were attached via a terminal box. An aluminum frame was attached via a gasket. Here, in order to obtain the reliability of the module, it is preferable to apply butyl rubber without any gap around the laminated body corresponding to the side surface of the glass and then incorporate it into the gasket, but here the difference from the comparative example is clear. It was not applied on purpose.

(Example 2)
The transparent surface plate 22 is the same as Example 1 except that a low iron content tempered glass plate having a thickness of 3.2 mm and a size of 92 cm × 46 cm is used. The processing time of the vacuum laminator was adjusted to be longer than that of Example 1 in consideration of an increase in heat capacity due to glass. Specifically, 45 minutes. The aluminum frame and gasket were slightly redesigned to take into account the increase in thickness.

(Example 3)
Translucent glass substrate made of low iron content soda-lime glass having an area of 91.5 cm × 45.5 cm and a thickness of 4 mm on a low iron content tempered glass plate having a thickness of 3.2 mm and a size of 92 cm × 92 cm as the transparent surface plate 22 Two solar cell element substrates having solar cell elements formed on 1 were arranged as shown in FIG. Other conditions are the same as in Example 2. In this case, two solar cell element substrates are electrically connected in parallel. In addition, there is a 5 mm gap between the two translucent glass substrates. In order to fill this gap, an EVA sheet having a width of 10 mm is formed along the gap with the first adhesive EVA and the second adhesive. A negative vacuum laminating step is performed on the adhesive EVA. The outline is shown in FIG. An insulating sheet 27 sandwiched between EVA is placed on the element, and a copper foil ribbon 26 connected to the bus bar electrode is placed thereon. Overlay EVA and back plate. The EVA has a notch for passing a line, and the back plate has a hole. The back plate (PVF / Al / PET) 24 is provided with holes. An insulating sheet is stacked in the hole to prevent contact between Al contained in the back plate and the copper foil ribbon.

  In addition, although wiring is similarly performed about Example 1, 2 and a comparative example, since those methods are described in Unexamined-Japanese-Patent No. 2000-077383, description is abbreviate | omitted in this application.

(Comparative Example 1)
The structure which provides the transparent surface board 22 in the surface which did not form the element of the translucent glass substrate 1 like FIG. 4 is abbreviate | omitted, and the 2nd adhesive agent 23 and the backplate 24 are made into the translucent glass substrate 1 of FIG. The same structure as in Example 1 was obtained except that the size was the same.

  About the solar cell module of Example 1, Example 2, and Comparative Example 1, the electrochemical corrosion measurement test was implemented. In addition, although Example 3 cannot carry out a test because the size of the solar cell module is large, the same result is expected since it is substantially the same as the structure of Example 2.

  The positive and negative electrodes of the connection terminal are electrically short-circuited, a DC voltage of 100 V is applied between the terminal and the frame so that the potential of the cell part becomes negative, and the solar cell module is immersed in hot water at 50 ° C. The course of mechanical corrosion was observed.

  In the case of the comparative example, the start of the peeling of the transparent electrode was observed at the end portion of the solar cell element in about 30 days, whereas the peeling did not occur even after 60 days had passed in both Example 1 and Example 2. I couldn't see it. In some cases, the semiconductor layer at the edge of the substrate is locally transparent and a metal color is observed. In the comparative example, the tendency was seen in 40 days, whereas in the example, 80 days. But there is no discoloration.

  In the case of the examples, in order to investigate changes due to electrochemical corrosion in a short period of time, the step of applying butyl rubber without any gaps around the laminated body corresponding to the side surface of the glass was omitted. Extends 3 to 6 times, so that solar cells are always protected for more than a year even when submerged. Since there is no situation where it is always submerged in actual use, it is possible to guarantee the reliability of about 25 years, which is said to be the life of the solar cell.

Sectional drawing of the thin film solar cell module of this invention Top view of thin film solar cell module of the present invention The thin-film solar cell module of the present invention in which the translucent surface plate according to Example 3 is tempered glass and two solar cell element substrates are placed thereon. Cross-sectional view of a conventional thin-film solar cell module Crystalline solar cell module (prior art)

Explanation of symbols

1 Translucent glass substrate 2 Transparent electrode layer (tin oxide layer)
3 Transparent electrode layer scribe line 4 Optical semiconductor layer (a-Si layer)
DESCRIPTION OF SYMBOLS 5 Opto-semiconductor layer scribe line 6 Back surface electrode layer 7 Back surface electrode layer scribe line 8 Bus bar wiring 9 Edge exposure part 10 Bus bar electrode 11a, 11b String 12 in both ends 12 Processing part for string separation 13 Laser insulation separation line 14 Special solder

21 First adhesive 22 Transparent surface plate 23 Second adhesive 24 Back plate 25 Third adhesive 26 Copper foil ribbon 27 Insulating sheet sandwiched between EVA

Claims (3)

From the light incident side, a configuration in which the transparent front plate, the first adhesive, the translucent glass substrate, the transparent electrode layer, the optical semiconductor, the back electrode layer, the second adhesive, and the back plate are arranged. A thin film solar cell module comprising:
A solar cell is formed by sequentially laminating a transparent electrode layer, an optical semiconductor layer, and a back electrode layer from the light incident side on the surface far from the light incident side of the translucent glass substrate,
A transparent surface plate is bonded via a first adhesive on the light incident side of the translucent glass substrate,
A photovoltaic cell is formed on a surface far from the light incident side of the light transmissive glass substrate, and a back surface of the light transmissive glass substrate far from the light incident side is interposed through a second adhesive. A thin-film solar cell module including a structure in which plates are bonded,
The side surface of the translucent glass substrate is covered with a third adhesive all around,
All the surfaces including the side surface of the translucent glass substrate are covered with the adhesive layer,
The first adhesive, the second adhesive, and the third adhesive are the same adhesive, and the adhesive is continuous at least on the side surface of the translucent glass substrate. Battery module. The size of the transparent front plate according to claim 1 and the size of the back plate are:
The size of the light-transmissive glass substrate and the thickness of the third adhesive provided on the side surface,
The thin film solar cell module according to claim 1, wherein the thin film solar cell module is the same or larger.   The thin film solar cell module according to claim 1 or 2, wherein the transparent surface plate according to claim 1 is tempered glass.

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