JP2008091419A - Solar cell module and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin-film solar cell module wherein films are hard to be peeled off even if water content enters. <P>SOLUTION: The solar cell module is provided with a photovoltaic layer wherein a plurality of photovoltaic elements that are formed by stacking a transparent conductive film 11, photoelectric conversion layers 12 and 13 and a back electrode 14 in sequence on a transparent substrate 10 are connected in series. It is also provided with a laminated body 20 that is arranged on the transparent substrate 10 at the end of the peripheral area existing around the vicinity of the power generating area of the solar cell module and is electrically isolated from the photovoltaic layer; and a filler 15 made of resin that is arranged on the photovoltaic layer and the laminated body 20. The bridging rate of a filler 17 on the laminated body 20 is higher than that of the filler 15 on the photovoltaic layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a photovoltaic layer in which a plurality of photovoltaic elements in which a first electrode, a photoelectric conversion layer, and a second electrode are sequentially laminated on a transparent substrate, and a filler made of a resin. The present invention relates to a solar cell module in which and are sequentially arranged, and a method for manufacturing the solar cell module.

  In recent years, in order to achieve both low cost and high efficiency of solar cells, thin-film solar cell modules that use less raw materials have been vigorously developed. An example of a cross-sectional view of such a thin-film solar cell module is shown in FIGS.

  In general, a photovoltaic element of a thin film solar cell module includes a first electrode 111 / photoelectric conversion layer 112, 113 / second electrode 113 on a transparent substrate 110 having a water-impervious property such as glass, and a laser from the substrate side. It is formed by laminating while patterning by irradiation. The thin film solar cell module is formed by adhering a protective material 116 such as PET (Poly Ethylene Terephthalate) on the photovoltaic element with a filler 115 such as EVA (Ethylene Vinyl Acetate) (for example, a patent). Reference 1).

The filler 115 has a function as an adhesive and a buffer between the protective material 116 and the photovoltaic element, and the protective material 116 has a function of preventing moisture from entering from the outside.
Japanese Unexamined Patent Publication No. 63-261883

 Since solar cell modules are used outdoors for a long period of time, there is a need for reliability that prevents moisture intrusion and film peeling.

 However, in the conventional technique, as shown in FIGS. 7 and 8, moisture has entered from the end of the solar cell module through the bonding surface between the filler 115 and the transparent substrate 110. Further, peeling of the film frequently occurred due to the penetration of moisture, such as peeling of the interface between the surface of the transparent substrate 110 and the photoelectric conversion layer 112.

 Then, in view of said problem, this invention aims at providing the manufacturing method of a solar cell module which prevents the penetration | invasion of a water | moisture content, and a film | membrane does not peel easily.

  The first feature of the present invention is that a photovoltaic layer in which a plurality of photovoltaic elements in which a first electrode, a photoelectric conversion layer, and a second electrode are sequentially stacked is connected in series is disposed on a transparent substrate. The solar cell module is disposed on the transparent substrate at the end of the peripheral region existing along the periphery of the power generation region of the solar cell module, and is electrically separated from the photovoltaic layer. A laminated body in which the first electrode and the photoelectric conversion layer are sequentially laminated, and a filler made of a resin disposed on the photovoltaic layer and the laminated body. The gist is that the crosslinking rate is a solar cell module higher than the crosslinking rate of the filler on the photovoltaic layer.

  According to the solar cell module according to the first feature, by disposing the laminated body at the end of the peripheral region, it is possible to prevent moisture from entering from the end via the adhesive surface between the filler and the transparent substrate. At the same time, by increasing the cross-linking rate of the filler in the peripheral region, the adhesion between the second electrode and the filler is improved and moisture is prevented from entering. Thus, in order to prevent moisture from entering, it is possible to make it difficult for the film to peel off.

  In the solar cell module according to the first feature, the crosslinking rate of the filler on the laminate is preferably 85% or more.

  The second feature of the present invention is that a photovoltaic layer in which a plurality of photovoltaic elements in which a first electrode, a photoelectric conversion layer, and a second electrode are sequentially stacked is connected in series is disposed on a transparent substrate. A method for producing a solar cell module, wherein a photovoltaic layer is formed on a transparent substrate, and on the transparent substrate at the end of the peripheral region existing along the periphery of the power generation region of the solar cell module, A step of forming a laminate in which the first electrode, the photoelectric conversion layer, and the second electrode are sequentially laminated, which are electrically separated from the photovoltaic layer, and the photovoltaic layer and the laminate, A sun including a step of disposing a filler made of resin and a step of irradiating a laser beam having a wavelength absorbed by the upper portion of the laminate along the periphery of the power generation region from the surface side on which the filler is disposed The gist of the present invention is a battery module manufacturing method.

  According to the manufacturing method of the solar cell module according to the second feature, moisture is intruded from the end portion through the bonding surface between the filler and the transparent substrate by arranging the laminate at the end portion of the peripheral region. In addition, the adhesiveness between the second electrode and the filler is improved by irradiating the peripheral region with laser light, and moisture is prevented from entering. Thus, in order to prevent moisture from entering, it is possible to make it difficult for the film to peel off.

  ADVANTAGE OF THE INVENTION According to this invention, the penetration | invasion of a water | moisture content is prevented and the manufacturing method of a solar cell module and a solar cell module which are hard to produce film | membrane peeling can be provided.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(Solar cell module)
A top view of the thin film solar cell module according to this embodiment is shown in FIG. The thin-film solar cell module has a power generation region in the center frame (outlined region). 2 is a cross-sectional view taken along the line AA of FIG. 1, and is an enlarged view of the upper end surface of FIG. 1 (the portion surrounded by a circle in FIG. 1).

  As shown in FIG. 2, the thin-film solar cell module according to this embodiment includes a photovoltaic layer, a filler 15, a protective material 16, and a plurality of photovoltaic elements connected in series on a transparent substrate 10. Are arranged in order. The photovoltaic element is formed by sequentially laminating a transparent conductive film (first electrode) 11, photoelectric conversion layers 12 and 13, and a back electrode (second electrode) 15. In FIG. 1, a plurality of photovoltaic elements, a filler 15, and a protective material 16 are sequentially arranged on the back side of the transparent substrate 10 opposite to the light incident side.

  The transparent substrate 10 is a single substrate of the solar cell module, and a plurality of photovoltaic elements are formed on the back surface side of the transparent substrate 10 opposite to the light incident side. The transparent substrate 10 is made of a light transmissive member such as glass.

The transparent conductive film 11 (first electrode) is formed in a strip shape when the transparent substrate 10 is viewed in plan. The transparent conductive film 11 is made of ZnO, In ₂ O ₃ , SnO ₂ , CdO, TiO ₂ , CdIn ₂ O ₄ , Cd ₂ SnO ₄ , Zn ₂ SnO ₄ and a metal oxide doped with Sn, Sb, F, and Al. It is composed of one or more types of laminates selected from a group. ZnO is suitable as a transparent conductive film material because it has high light transmittance, low resistance, and plasticity, and is inexpensive.

  The photoelectric conversion layers 12 and 13 are formed in a strip shape on the transparent conductive film 11. The photoelectric conversion layers 12 and 13 are made of an amorphous silicon semiconductor. The photoelectric conversion layers 12 and 13 according to the present embodiment are composed of an amorphous silicon semiconductor and a microcrystalline silicon semiconductor, respectively. Note that in this specification, the term “microcrystal” means a material containing a large number of fine crystal grains, and also means a state partially including an amorphous state.

  Here, the photoelectric conversion layer 12 according to this embodiment is formed by sequentially stacking pin-type amorphous silicon semiconductors, and the photoelectric conversion layer 13 is formed by sequentially stacking pin-type microcrystalline silicon semiconductors. The Such a tandem solar cell module using amorphous silicon and microcrystalline silicon has a structure in which two types of semiconductors having different light absorption wavelengths are stacked, and can effectively use the sunlight spectrum.

  The back electrode 14 (second electrode) is formed in a strip shape on the photoelectric conversion layers 12 and 13. The back electrode 14 is made of a conductive member such as Ag.

  The protective material 16 is disposed on the filler 15. The protective material 16 is comprised by resin films, such as PET, PEN, ETFE, PVDF, PCTFE, PVF, PC, acrylic, and glass.

  The protective material 16 is bonded onto the photovoltaic element by the filler 15. The filler 15 is made of a resin such as EVA, EEA, PVB, silicon, urethane, acrylic, or epoxy. The filler 15 has a function as an adhesive and a buffer between the protective material 16 and the photovoltaic element.

  Further, on the transparent substrate 10 at the end of the peripheral region existing along the periphery of the power generation region of the solar cell module, a transparent conductive film 11 and a photoelectric conversion layer that are electrically separated from the photovoltaic layer. A stacked body 20 in which 12, 13 and the back electrode 14 are sequentially stacked is disposed. Here, the laminated body 20 is an ineffective region that is not subjected to power generation, and it is sufficient that at least the transparent conductive film 11 and the photoelectric conversion layer are laminated.

  Moreover, the crosslinking rate of the filler 17 on the laminate 20 is higher than the crosslinking rate of the filler 15 on the photovoltaic layer. That is, there is a filler 17 that has been denatured so as to increase the cross-linking rate between the back electrode 14 and the filler 15 constituting the laminate 20. The crosslinking rate of the filler 17 is preferably 85% or more. Here, the crosslinking rate of the filler was determined by measuring the gel fraction in the crosslinking material. The filler 17 was peeled off from the solar cell module, and the weight was measured. Next, the filler 17 was immersed in a xylene solvent to elute a region that was not crosslinked and was in a sol state in the solvent. The xylene solution was then evaporated and the cross-linked gel region was extracted. And the weight of the extracted gel area | region was measured and the gel fraction was calculated | required by taking the ratio with respect to the weight before immersion in a solvent. The calculation formula is as follows.

Gel fraction (%) = (weight of undissolved portion / original weight of sample) × 100
The gel fraction thus determined is defined as the crosslinking rate in the present application.

  FIG. 3 shows a cross-sectional structure of the solar cell module according to this embodiment. The solar cell module 100 described above is attached with a metal frame 31 such as aluminum with a resin 30 such as butyl rubber interposed along its end. A portion not covered with the resin 30 and the metal frame 31 is a power generation region (effective region) of the solar cell module 100. In the present embodiment, the crosslinking rate of the filler in the peripheral part covered with the metal frame 31 of the solar cell module 100 is higher than the crosslinking rate of the filler having the crosslinking rate in the central part.

(Method for manufacturing solar cell module)
A method for manufacturing the thin-film solar cell module according to this embodiment will be described with reference to FIGS.

  As shown in FIG. 4A, a transparent conductive film 11 is formed on a transparent substrate 10 by sputtering. And as shown in FIG.4 (b), the transparent conductive film 11 is patterned in strip shape by irradiation of a YAG laser, and is electrically isolate | separated between each photovoltaic device.

  Next, as shown in FIG. 4C, the photoelectric conversion layers 12 and 13 are formed by plasma CVD. Specifically, a pin-type amorphous silicon semiconductor is sequentially stacked on the transparent conductive film 11 to form a photoelectric conversion layer 12, and a pin-type microcrystalline silicon semiconductor is sequentially stacked on the photoelectric conversion layer 12. Thus, the photoelectric conversion layer 13 is formed. As shown in FIG. 4D, the photoelectric conversion layers 12 and 13 are patterned into strips by irradiating a YAG laser at a predetermined distance from the patterning position of the transparent conductive film 11.

  Next, as shown in FIG. 4E, the back electrode 14 is formed on the photoelectric conversion layer 13 by sputtering or the like. Next, as shown in FIG. 4 (f), the back electrode 14 is patterned into a strip shape by irradiating YAG laser from the back side at a predetermined distance from the patterning position of the photoelectric conversion layers 12 and 13. , Dry etched to desired depth.

  In this way, a photovoltaic layer formed by connecting a plurality of photovoltaic elements in series is formed on the transparent substrate 10, and the edge of the peripheral region existing along the periphery of the power generation region of the solar cell module. On the transparent substrate 10, a laminate 20 is formed that is electrically separated from the photovoltaic layer.

  Next, in this embodiment, as shown in FIG. 5A, a filler 15 and a protective material 16 made of resin are sequentially arranged on the photovoltaic layer and the laminate 20, and a laminating apparatus is used. Then vacuum heat press.

  Next, as shown in FIG. 5B, laser light having a wavelength that is absorbed by the upper portion of the stacked body 20 along the periphery of the power generation region from the surface side on which the filler 15 and the protective material 16 are disposed. Irradiate. The area around the power generation area is an invalid area that does not contribute to power generation. Thus, by irradiating the laser beam, the filler 17 that has been altered so as to increase the crosslinking rate can be formed.

  In this way, the thin film solar cell module according to this embodiment as shown in FIG. 2 is formed. In addition, a terminal box and an extraction electrode can be connected to the solar cell module, and an aluminum frame can be attached with butyl rubber or the like.

(Function and effect)
According to the solar cell module according to the present embodiment, by arranging the stacked body 20 at the end of the peripheral region, moisture can enter from the end via the bonding surface between the filler 15 and the transparent substrate 10. Can be prevented. Further, by increasing the cross-linking rate of the filler 17 in the peripheral area, which is an ineffective area, the adhesion between the back electrode 14 and the filler 17 is improved, and moisture enters from the interface between the back electrode 14 and the filler 17. This can be prevented. Thus, in order to prevent moisture from entering, it is possible to make it difficult for the film to peel off.

  Moreover, it is preferable that the crosslinking rate of the filler 17 on the laminated body 20 is 85% or more. By setting it to 85% or more, the hardness of the filler 17 can be further improved.

  A high cross-linking rate means a decrease in the molecular motion that forms the resin, which improves the adhesion to the substrate and the hardness of the resin itself, but decreases the mechanical properties (elastic modulus, tensile strength). Therefore, when the cross-linking rate of the central portion exposed to the natural phenomenon of the solar cell module 100 shown in FIG. 3 is high, the natural phenomenon that works in the direction of lowering the molecular motion causes cracks and the like, and moisture easily enters. Become. Thus, an optimal crosslinking rate is required at the center of the solar cell module. In the present embodiment, by increasing the cross-linking rate of only the ineffective region at the end, it is possible to prevent moisture from entering from the end and keep the cross-linking rate at the center as optimum.

  Moreover, according to the manufacturing method of the solar cell module which concerns on this embodiment, the crosslinking rate of the filler 17 which exists in a peripheral area | region can be raised by irradiating the peripheral area | region which is an invalid area | region with a laser beam. For this reason, the adhesiveness of the back surface electrode 14 and the filler 17 can be improved, and it can prevent that a water | moisture content penetrate | invades. Thus, in order to prevent moisture from entering, it is possible to make it difficult for the film to peel off.

(Other embodiments)
Although the present invention has been described according to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the above embodiment, the photoelectric conversion layers 12 and 13 in which an amorphous silicon semiconductor and a microcrystalline silicon semiconductor are sequentially stacked are used. However, a single layer or three or more layers of a microcrystalline or amorphous silicon semiconductor are used. The same effect can be obtained even if the laminate is used.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  Hereinafter, the thin film solar cell module according to the present invention will be specifically described with reference to examples, but the present invention is not limited to those shown in the following examples, and the gist thereof is not changed. In the range, it can implement by changing suitably.

(Example)
As the thin film solar cell module according to the example of the present invention, the solar cell module shown in FIG. 2 was manufactured as follows.

As shown in FIG. 4A, a 600 nm thick ZnO electrode 11 was formed on a 4 mm thick glass substrate 10 by sputtering. Thereafter, as shown in FIG. 4B, the ZnO electrode 11 was patterned into a strip shape by irradiating a YAG laser from the light incident side of the glass substrate 10. For the laser separation processing, an Nd: YAG laser having a wavelength of about 1.064 μm, an energy density of 13 J / cm ³ and a pulse frequency of 3 kHz was used.

Next, an amorphous silicon semiconductor layer 12 and a microcrystalline silicon semiconductor layer 13 were formed by plasma CVD as shown in FIG. Specifically, the amorphous silicon semiconductor layer 12 is a p-type amorphous silicon semiconductor layer having a thickness of 10 nm from a mixed gas of SiH ₄ , CH ₄ , H _2, and B ₂ H ₆ by plasma CVD. SiH ₄ and i-type amorphous silicon semiconductor layer having a film thickness of 300nm with a gas mixture of H _2, the n-type amorphous silicon semiconductor layer having a film thickness of 20nm from a mixed gas of SiH _4, H _2, and PH ₃ Formed and sequentially laminated. Further, the microcrystalline silicon semiconductor layer 13 by a plasma CVD method, a gas mixture of SiH ₄ and H _2, and B ₂ H ₆ a p-type microcrystalline silicon semiconductor layer having a thickness of 10 nm, of SiH ₄ and H ₂ An i-type microcrystalline silicon semiconductor layer having a thickness of 2000 nm was formed from a mixed gas, and an n-type microcrystalline silicon semiconductor layer having a thickness of 20 nm was formed from a mixed gas of SiH ₄ , H _2, and PH ₃ and sequentially stacked. Table 1 shows the details of various conditions of the plasma CVD method.

Also, as shown in FIG. 4D, the amorphous silicon semiconductor layer 12 and the microcrystalline silicon semiconductor layer 13 are irradiated with a YAG laser from the light incident side at a position 50 μm lateral from the patterning position of the ZnO electrode 11. Were patterned into strips. For the laser separation processing, an Nd: YAG laser having a wavelength of 532 nm, an energy density of 0.7 J / cm ³ , and a pulse frequency of 3 kHz was used.

Next, as shown in FIG. 4E, an Ag electrode 14 having a thickness of 200 nm was formed on the microcrystalline silicon semiconductor layer 13 by sputtering. Further, as shown in FIG. 4 (f), the amorphous silicon semiconductor layer 12, the microcrystalline silicon semiconductor layer 13, and the Ag electrode 14 were patterned into strips by irradiating YAG laser from the back side. For the laser separation processing, an Nd: YAG laser having a wavelength of 532 nm, an energy density of 0.7 J / cm ³ , and a pulse frequency of 4 kHz was used. Further, dry etching with CF ₄ was performed for several tens of seconds.

  Next, as shown in FIG. 5A, the EVA 15 and the PET film 16 are sequentially arranged on the photovoltaic element, and the EVA 15 is heated at 150 ° C. for 30 minutes using a laminating apparatus. Cross-linked, stabilized and vacuum bonded.

  Next, as shown in FIG. 5B, laser light having a wavelength (915 nm) that is substantially transmitted through the EVA 15 and the PET film 16 along the periphery of the power generation region from the surface side on which the PET film 16 is disposed. Irradiated. At this time, the crosslinking rate of EVA17 in the peripheral region was 85%. Moreover, the crosslinking rate of EVA15 other than the peripheral region was 80%.

  Finally, a thin film solar cell module according to an embodiment of the present invention was completed by attaching a terminal box and connecting an extraction electrode.

(Conventional example)
As a conventional example, a solar cell module shown in FIG. 8 was produced. In the conventional example, the patterning of the YAG laser was changed as compared with the example, and the same process as the example was performed except that the alteration process of the EVA 15 in the peripheral region shown in FIG. 5B was not performed. That is, as shown in FIG. 8, there is no photoelectric conversion element at the end of the solar cell module. Therefore, an interface between the glass substrate 110 and the EVA 115 exists at the end.

(Reliability evaluation)
The weather resistance reliability evaluation for comparing the reliability of the thin film solar cell module according to the example and the thin film solar cell module according to the conventional example was performed. Specifically, according to IEC61646, each module in an environment of a temperature of 85 ° C. and a humidity of 85% was exposed for 1000 hours.

(result)
In the conventional example, peeling occurred at the interface between the glass substrate 110 and the amorphous silicon semiconductor layer 12 within 100 hours, as shown in FIG. FIG. 6 shows that the interface between the glass substrate 110 and the amorphous silicon semiconductor layer 112 is peeled in the region where the transparent conductive film 111 (first electrode) is removed.

  On the other hand, in the examples, no peeling occurred even after 1000 hours. For this reason, it has been found that by disposing the laminate 20 around the power generation region, moisture can be prevented from entering from the end portion through the adhesive surface between the EVA 15 and the glass substrate 10. It was also found that by increasing the cross-linking rate of the EVA 17 in the peripheral region, which is an ineffective region, the adhesion between the Ag electrode 14 and the EVA 17 having a high cross-linking rate can be improved, and moisture can be prevented from entering. Thus, it was found that the occurrence of film peeling can be suppressed in order to prevent moisture from entering.

It is a top view of the thin film type solar cell module according to the present embodiment. It is a figure which shows the edge part of the AA cross section of FIG. It is sectional drawing of the thin film type solar cell module which concerns on this embodiment. It is a schematic diagram which shows the manufacturing method of the thin film type solar cell module which concerns on this embodiment (the 1). It is a schematic diagram which shows the manufacturing method of the thin film type solar cell module which concerns on this embodiment (the 2). It is a figure which shows the peeling of the interface in the reliability test of the thin film type solar cell module which concerns on a prior art example. It is sectional drawing which shows the structure of the conventional thin film type solar cell module (the 1). It is sectional drawing which shows the structure of the conventional thin film type solar cell module (the 2).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,110 ... Transparent substrate 11, 111 ... Transparent electrically conductive film 12, 13, 112, 113 ... Photoelectric conversion layer 14, 114 ... Back electrode 15, 115 ... Filler 16, 116 ... Protective material 17 ... Altered filler 20 ... Laminate 30 ... Resin 31 ... Metal frame 100 ... Solar cell module

Claims (3)

A solar cell module in which a photovoltaic layer in which a plurality of photovoltaic elements in which a first electrode, a photoelectric conversion layer, and a second electrode are sequentially stacked is connected in series is disposed on a transparent substrate,
A first electrode disposed on the transparent substrate at an end of a peripheral region that exists along the periphery of the power generation region of the solar cell module, and electrically separated from the photovoltaic layer; A laminate in which a photoelectric conversion layer is sequentially laminated;
A filler made of resin, disposed on the photovoltaic layer and the laminate,
The solar cell module, wherein a crosslinking rate of the filler on the laminate is higher than a crosslinking rate of the filler on the photovoltaic layer.   The solar cell module according to claim 1, wherein a crosslinking rate of the filler on the laminate is 85% or more. In a method for manufacturing a solar cell module, a photovoltaic layer in which a plurality of photovoltaic elements in which a first electrode, a photoelectric conversion layer, and a second electrode are sequentially laminated is arranged on a transparent substrate is disposed. There,
The photovoltaic layer is formed on the transparent substrate, and the photovoltaic layer is electrically formed on the transparent substrate at the end of the peripheral region along the periphery of the power generation region of the solar cell module. Forming a stacked body in which the first electrode and the photoelectric conversion layer are sequentially stacked, and
A step of disposing a filler made of resin on the photovoltaic layer and the laminate;
Irradiating laser light having a wavelength that is absorbed by the upper part of the laminate along the periphery of the power generation region from the surface side on which the filler is disposed. Production method.

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