JP2012069566A - Thin film solar cell manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce damage to a glass substrate in a peripheral film removal process of a thin film solar battery, thereby reducing laminate film particles left on the substrate in a peripheral region and preventing shorting between adjacent cells.SOLUTION: A thin film solar battery disposes on a substrate 1 made of glass a plurality of unit cells of a thin film solar battery having a laminate film 7 composed of a first electrode layer 2, a photoelectric conversion layer 4, and a second electrode layer 6 which are laminated one on top of another. The manufacturing method for the thin film solar battery comprises: a process of forming a heat resistant resin layer 8 on the outer periphery of the substrate 1; a process of laminating the laminate film 7 on the substrate 1 which has the heat resistant resin layer 8 formed thereon; a separation groove formation process of forming a plurality of separation grooves (91, 93) which divide the laminate film 7 into plural unit cells continuously until they reach the top of the heat resistant resin layer 8 on the outer periphery of the substrate 1; and an outer peripheral film removal process which includes a process of leaving partially the laminate film 7 on the heat resistant resin layer 8 which has separation grooves formed therein and removing the rest of the laminate film 7 on the outside thereof together with the heat resistant resin layer 8.

Description

  The present invention relates to a method for manufacturing a thin film solar cell.

  Conventionally, in an integrated thin film solar cell having a large number of thin film solar cells on one glass substrate, a first electrode layer made of a transparent electrode layer, a photoelectric conversion layer made of a thin film semiconductor, a metal layer on a transparent insulating substrate The 2nd electrode layer which consists of is formed in order. As a method for insulating and separating adjacent thin film solar cells, processing by a laser beam is often used because of cost and stability.

  Such a thin-film solar cell module generally has a structure in which the conductive film around the substrate is removed in order to improve electrical insulation from the outside. For example, in Patent Document 1, the thin-film solar cell is provided at the center of the glass substrate so that the substrate is exposed in the surrounding area. The transparent electrode layer, the semiconductor layer, and the back electrode layer in the periphery of the transparent insulating substrate are removed by mechanical removal means such as polishing, and the transparent electrode layer, semiconductor layer, and back surface are removed by means such as laser processing inside the removed area. The electrode layer is removed. By performing such processing, even if the region removed by means such as polishing is not sufficiently polished, it can be reliably insulated. In order to protect the thin film solar cell, a back sheet or the like is attached using an EVA adhesive sheet or the like. In Patent Document 1, by removing the surface of the glass substrate by machining, the peripheral region of the substrate is used as a good adhesion / seal surface with the back sheet.

  Patent Document 2 discloses a method for forming an electrode pattern with a simple process and no damage to the substrate. A resist pattern extracted in the shape of an electrode is formed on a substrate, an electrode film is formed thereon, and the resist pattern is mechanically peeled to form an electrode. Thus, the electrode film on the entire outer periphery of the substrate is removed.

  Patent Document 3 discloses a method of providing a mask covering a predetermined region from the periphery of the substrate, sequentially depositing the first electrode layer, the photoelectric conversion layer, and the second electrode layer, and then removing the mask. Yes.

JP 2000-150944 A JP-A-10-275920 JP 2008-300732 A

  As in Patent Document 1, if the substrate is mechanically processed at the time of peeling of the peripheral film, there is a problem that the substrate is damaged starting from scratches around the substrate. In addition, in the methods of Patent Documents 2 and 3, damage to the substrate can be prevented, but when applied to a structure in which the first electrode layer, the photoelectric conversion layer, and the second electrode layer are stacked, the resist pattern and the mask are stacked at the edges. There is a problem that the structure is disturbed or damaged, and the contact between the front electrode layer and the back electrode layer or the short circuit between adjacent cells is likely to occur. In addition, there is a problem that when the laminated film formed directly on the substrate is removed by laser scribing, the particles of the laminated film are likely to remain on the substrate.

  Therefore, the present invention reduces the damage to the glass substrate in the step of removing the peripheral film of the thin film solar cell, reduces the number of laminated film particles remaining on the substrate in the peripheral region, and prevents a short circuit between adjacent cells. It aims at providing the manufacturing method of.

In the method for producing a thin film solar cell of the present invention, a plurality of unit cells of a thin film solar cell having a laminated film in which a first electrode layer, a photoelectric conversion layer, and a second electrode layer are laminated are arranged on a substrate made of a glass material. A method of manufacturing a thin film solar cell, the step of forming a heat-resistant resin layer on the outer periphery of the substrate,
The step of laminating the laminated film on the substrate on which the heat-resistant resin layer is formed, and a plurality of separation grooves for dividing the laminated film into a plurality of unit cells are continued up to the heat-resistant resin layer on the outer peripheral portion of the substrate. An outer periphery including a step of forming a separation groove and a step of partially leaving the laminated film on the heat-resistant resin layer on which the separation groove is formed and removing the laminated film on the outer side together with the heat-resistant resin layer And a film removal step.

  In the present invention, in the outer peripheral film removing step, the laminated film is partially left on the heat resistant resin layer in which the separation groove is formed, and the laminated film is removed together with the heat resistant resin layer, thereby reducing damage to the glass substrate. The particles of the laminated film remaining on the substrate in the peripheral region can be reduced. In addition, since a plurality of separation grooves that are divided into unit cells are formed so as to continue to the top of the heat resistant resin layer on the outer peripheral portion of the substrate, a short circuit between adjacent cells that is likely to occur at the end of the heat resistant resin layer is prevented. Can be prevented.

It is a top view which shows schematic structure of the thin film solar cell of Embodiment 1 of this invention. It is sectional drawing which shows schematic structure of the thin film solar cell of Embodiment 1 of this invention. It is sectional drawing and the top view explaining the manufacturing method of the thin film solar cell of this Embodiment 1. FIG. It is sectional drawing and the top view explaining the manufacturing method of the thin film solar cell of Embodiment 1 of this invention. It is sectional drawing and the top view explaining the manufacturing method of the thin film solar cell of Embodiment 1 of this invention. It is sectional drawing and the top view explaining the manufacturing method of the thin film solar cell of Embodiment 1 of this invention. It is sectional drawing and the top view explaining the manufacturing method of the thin film solar cell of Embodiment 1 of this invention. It is sectional drawing and the top view explaining the manufacturing method of the thin film solar cell of Embodiment 1 of this invention. It is sectional drawing explaining the structure of the solar cell module using the thin film solar cell of Embodiment 1 of this invention. It is a top view which shows schematic structure of the thin film solar cell of Embodiment 2 of this invention. It is sectional drawing explaining the manufacturing process of the thin film solar cell of Embodiment 2 of this invention. It is sectional drawing explaining the structure of the solar cell module using the thin film solar cell of Embodiment 2 of this invention. It is a top view explaining the middle of manufacture of the thin film solar cell of Embodiment 3 of this invention. It is sectional drawing explaining the manufacture middle of the thin film solar cell of Embodiment 3 of this invention.

  Embodiments of a method for manufacturing a thin film solar cell according to the present invention will be described below with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. In the drawings shown below, the scale of each member may be different from the actual scale for easy understanding. The same applies between the drawings. Further, in the embodiment, the same components are denoted by the same reference numerals, and the detailed description of the components described in one embodiment will be omitted in another embodiment.

<Embodiment 1>
FIG. 1 is a top view showing a schematic structure of a thin-film solar cell according to Embodiment 1 of the present invention. 2 is a cross-sectional view showing a schematic structure of the thin-film solar cell according to Embodiment 1 of the present invention. FIG. 2 (a) is a cross-sectional view taken along the line AA 'in FIG. 1, and FIG. 1 corresponds to a cross-sectional view taken along line BB ′. A thin film solar cell 100 according to the first embodiment has a plurality of unit cells 10 disposed on a substrate 1. The unit cell 10 is formed by dividing a laminated film 7 including the first electrode layer 2, the photoelectric conversion layer 4, and the second electrode layer 6 into a plurality of unit cells 10 by separation grooves 91 and 93. In the outer peripheral region 40 of the main surface of the substrate 1 on which the laminated film 7 is formed, the conductive laminated film 7 is removed, and the power generation region 30 in which the laminated film 7 remains is electrically insulated from the outer edge of the substrate 1. In order to improve electrical insulation, it is desirable to form the outer peripheral region 40 so that the distance between the power generation region 30 and the outer edge of the substrate 1 is 5 mm or more. On the other hand, since the amount of power generation decreases when the power generation region 30 becomes narrow, the distance between the power generation region 30 and the outer edge of the substrate 1 is preferably 20 mm or less.

  In the region near the outer peripheral region 40 in the power generation region 30 in FIG. 1, there is a heat resistant resin layer 8 between the laminated film 7 and the substrate 1. A portion indicated by a dotted line in FIG. 1 indicates the position of the end portion 29 of the heat resistant resin layer 8, and the heat resistant resin layer 8 exists on the outer peripheral side from the end portion 29. In the region where the heat-resistant resin layer 8 is present, the laminated film 7 is separated from the substrate 1 as compared with the region where the heat-resistant resin layer 8 which is the majority of the central portion of the power generation region 30 is not formed. The heat-resistant resin layer 8 has heat resistance that can withstand the process temperature for forming the first electrode layer 2, the photoelectric conversion layer 4, the second electrode layer 6, and the like. For example, an electrically insulating polyimide resin or polybenzimidazole resin Etc.

The thin film solar cell 100 is a super straight type thin film solar cell in which light is incident from the main surface of the substrate 1 opposite to the laminated film 7. The substrate 1 is made of a transparent insulating glass material having a small absorption from the visible region to the near infrared region. An underlayer such as a transparent silicon oxide (SiO ₂ ) film or silicon nitride (SiN) film may be formed on the substrate 1 made of glass. The first electrode layer 2 is made of a transparent conductive film mainly composed of zinc oxide (ZnO), indium tin oxide (ITO), tin oxide (SnO ₂ ), or the like. These transparent conductive films include at least selected from aluminum (Al), gallium (Ga), indium (In), boron (B), yttrium (Y), silicon (Si), zirconium (Zr), and titanium (Ti). One or more elements may be contained as a dopant. The first electrode layer 2 may be a layer formed by laminating transparent conductive films made of these plural materials. The first electrode layer 2 may have an uneven texture structure on the surface. This texture structure scatters incident sunlight and enhances the light use efficiency in the photoelectric conversion layer 4.

  The photoelectric conversion layer 4 is made of, for example, a semiconductor material containing silicon as a main component, such as amorphous silicon, amorphous silicon germanium, amorphous carbon-containing silicon, microcrystalline silicon, or microcrystalline silicon germanium. The photoelectric conversion layer 4 has a semiconductor junction structure (pin structure) in which p-type, i-type, and n-type having different semiconductor conductivity are stacked, and converts incident light into electricity. A pn structure in which p-type and n-type layers are stacked may be employed. The order of the junction may be a nip structure or an np structure that is upside down. The photoelectric conversion layer 4 may have a tandem structure in which a plurality of junction structures of different semiconductor materials are stacked. The second electrode layer 6 may be an electrode layer made of a metal having high reflectivity such as Ag. The second electrode layer 6 may have a structure in which a transparent electrode layer and a metal layer are sequentially laminated on the photoelectric conversion layer 4. Alternatively, the second electrode layer 6 may be only the transparent electrode layer, and a reflective material may be disposed on the back surface thereof.

  The typical shape of the substrate 1 is a rectangle, and the unit cell 10 is a rectangle elongated in a direction parallel to the side of the substrate 1. The unit cell 10 is formed by separating a laminated film including the first electrode layer 2, the photoelectric conversion layer 4, and the second electrode layer 6 with a groove. In FIG. 2A, the first groove 91 extends in the direction perpendicular to the paper surface and separates the first electrode layer 2 between the unit cells 10. The second groove 92 is a groove formed in the vicinity of the first groove 91 and extending in parallel with the first groove 91. The second groove 92 is formed by removing the photoelectric conversion layer 4 on the first electrode layer 2. The second electrode layer 6 is formed inside the second groove 92, and the second electrode layer 6 and the first electrode layer 2 are electrically connected at the bottom of the second groove 92. The second groove 92 is not necessarily a continuous groove. Further, the third groove 93 is formed at a position opposite to the first groove 91 in the vicinity of the second groove 92 by removing the photoelectric conversion layer 4 and the second electrode layer 6 on the first electrode layer 2. The photoelectric conversion layer 4 and the second electrode layer 6 between the unit cells 10 are separated. Thereby, the second electrode layer 6 of one adjacent unit cell 10 and the first electrode layer 2 of the other unit cell 10 are electrically connected in series. A plurality of unit cells 10 are connected in series, and electric power is taken out from both ends and used. The number of unit cells 10 on the substrate 1, the array shape, and the connection form can be changed as appropriate.

  As shown in FIG. 1, the first groove 91 and the third groove 93 separating the adjacent unit cells 10 are formed to reach the boundary between the outer peripheral region 40 and the power generation region 30 from which the conductive laminated film is removed. Yes. That is, the separation grooves of the first groove 91 and the third groove 93 are continuously formed from the end portion 29 to the outer peripheral side, up to a portion where the heat resistant resin layer 8 exists between the substrate 1 and the laminated film. The second groove 92 may be formed continuously up to the portion where the heat resistant resin layer 8 exists, but is not essential. The third groove 93 is formed on the inner peripheral side of the end portion 29 so that the first electrode layer 2 remains. On the outer peripheral side of the end portion 29, the first electrode layer 2, the photoelectric conversion layer 4, and the second electrode layer 6 are formed. All the laminated films may be removed. As described above, it is possible to prevent a short circuit between adjacent unit cells 10 on the outer peripheral side from the end portion 29. Further, the heat-resistant resin layer 8 has an inclined surface whose thickness decreases as it approaches the end portion 29 from the outer peripheral region 40. For this reason, it is easy to continuously form the separation grooves of the first groove 91 and the third groove 93 without interruption at the end portion 29.

  Next, the manufacturing method of the thin film solar cell of this Embodiment 1 is demonstrated. 3 to 8 are a cross-sectional view and a top view for explaining the method for manufacturing the thin-film solar cell of the first embodiment. In each figure, (b) is a top view, and (a) corresponds to a cross-sectional view taken along line A-A 'in (b).

  First, as shown in FIG. 3, the heat-resistant resin layer 8 is formed around the main surface of the substrate 1 made of a glass material. When polyimide is used as the heat resistant resin layer 8, a solution of polyamic acid (polyamic acid) is applied to the periphery of the substrate 1, and after drying, heat-treated at a temperature of 300 to 500 ° C. and imidized to form the heat resistant resin layer 8. Form. Solution coating methods include printing methods such as letterpress printing, offset printing, gravure printing, and inkjet printing, and coating methods such as die coating, dip coating, discharge coating, roll coating, and bar coating. it can. When photoelectric conversion is performed by the photoelectric conversion layer 4 on the heat-resistant resin layer 8 to be formed later, or when the laminated film is subjected to laser irradiation or the like through the substrate 1 in a subsequent process, a transparent material is used as the heat-resistant resin layer 8. It is desirable to use it. Before the heat resistant resin layer 8 is formed, the surface of the substrate 1 is subjected to surface treatment such as ultrasonic cleaning treatment, corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, ozone treatment, etc. in order to improve adhesion. More preferably, it is formed from

  The thickness of the heat-resistant resin layer 8 can be adjusted by the coating method, the component of the solution used as a raw material, and the viscosity. For example, when a solution containing 5 to 30% by mass as a solid component and having a viscosity of 0.1 to 10 Pascal seconds at 30 ° C. is applied, a heat resistant resin layer 8 of about 1 to 40 microns can be formed after the heat treatment. it can. When a solution having an appropriate viscosity is applied and formed in this manner, the solution flows slightly in the vicinity of the inner end portion 29, and a gentle slope reaching the substrate surface is formed in the vicinity of the end portion 29 of the heat resistant resin layer 8. The The angle formed between the main surface of the substrate 1 and the inclined surface near the end portion 29 is, for example, 20 to 70 degrees, and more preferably 45 degrees or less.

  The distance between the end portion 29 and the outer peripheral region 40, that is, the width of the heat-resistant resin layer 8 partially remaining on the outer periphery of the power generation region 30 is, for example, 0.5 to 3 mm. The width from the edge of the substrate 1 to which the heat-resistant resin layer 8 is applied is a width obtained by adding the width from the edge of the substrate 1 in the outer peripheral region 40 and the width of the heat-resistant resin layer 8 that remains partially. For example, 5 to 23 mm. The application region of the heat resistant resin layer 8 is preferably formed on the entire periphery of the substrate 1 as shown in FIG. For example, it is good also as only the area | region along two opposing sides of the board | substrate 1 in the tip which extended the 1st groove | channel 91 and the 3rd groove | channel 93 formed at a later process.

Next, a first electrode layer 2 such as ZnO or SnO ₂ is formed on the substrate 1 on which the heat-resistant resin layer 8 is formed in the periphery as shown in FIG. 4 by sputtering, vapor deposition, CVD, or the like. A first groove 91 for separating the first electrode layer 2 between the unit cells 10 is formed by a laser scribing method or the like. The thickness of the first electrode layer 2 is about 0.3 to 1 micron, and irregularities may be formed on the surface of the first electrode layer 2. In order to make the projections and depressions, there are a method of roughening by dipping in an etching aqueous solution such as hydrochloric acid (HCl), a method of roughening according to conditions at the time of film formation such as CVD. In the first electrode layer 2, a first groove 91 is continuously formed from the center of the substrate over the end portion 29 of the heat resistant resin layer 8 and onto the peripheral heat resistant resin layer 8. If the heat-resistant resin layer 8 is transparent, light may be incident from the substrate 1 opposite to the film surface when the first groove 91 is formed by laser scribing. Further, a laser scribing method in which laser is irradiated from the film surface, an etching process using a resist mask, or the like may be used. In order to process a transparent conductive material such as ZnO, it is preferable to use a fundamental wave (wavelength 1064 nm) of an Nd: YAG laser.

  Next, for example, a photoelectric conversion layer 4 mainly composed of Si is formed on the substrate 1 on which the first electrode layer 2 is formed as shown in FIG. 5 by a CVD method or the like, and the photoelectric conversion layer is further formed by a laser scribe method or the like. 4, the second groove 92 is formed. The photoelectric conversion layer 4 forms a semiconductor junction by depositing a p-layer, an i-layer, and an n-layer in order or in reverse order. The photoelectric conversion layer 4 is made of a material such as amorphous silicon, microcrystalline silicon, or amorphous silicon germanium, and has a total thickness of 0.3 to 5 microns. When laser scribing is performed so as to remove the photoelectric conversion layer 4 containing Si as a main component while leaving the first electrode layer 2 made of a transparent conductive material, a second harmonic (wavelength: 532 nm) of an Nd: YAG laser is used. good. The second groove 92 is preferably formed at a position slightly shifted from the first groove 91 and substantially parallel to the first groove 91. Similarly to the first groove 91, the second groove 92 may be formed continuously from the center of the substrate to the peripheral heat-resistant resin layer 8.

  Next, as shown in FIG. 6, a second electrode layer 6 mainly composed of Ag, for example, is formed on the substrate 1 on which the photoelectric conversion layer 4 is formed by sputtering or the like, and further the photoelectric conversion layer is formed by laser scribing or the like. 4 and the second electrode layer 6 are formed with a third groove 93. The first electrode layer 2, the photoelectric conversion layer 4, and the second electrode layer 6 are laminated to form a laminated film 7. The second electrode layer 6 may have a structure in which a transparent conductive film such as ZnO and a metal film such as Ag are sequentially stacked. The second electrode layer 6 is formed continuously from the top of the photoelectric conversion layer 4 to the inside of the second groove 92, and is electrically connected to the top of the photoelectric conversion layer 4 and the first electrode layer 2. In the formation of the third groove 93, laser scribing is performed so as to remove the photoelectric conversion layer 4 and the second electrode layer 6 while leaving the first electrode layer 2. For the processing, the second electrode (wavelength 532 nm) of an Nd: YAG laser having a high transmittance of the first electrode layer 2 is used for irradiation from the substrate 1 side. At the same time as the photoelectric conversion layer 4 is removed by laser scribing, the second electrode layer 6 thereon is also removed. Similarly to the first groove 91, the third groove 93 is also formed continuously from the center of the substrate to above the peripheral heat-resistant resin layer 8.

  Next, the outer peripheral film removing step will be described. First, as shown in FIG. 7, an outer peripheral groove 19 from which the laminated film 7 has been removed is formed on the outer peripheral side of the end portion 29 of the heat resistant resin layer 8. The outer peripheral groove 19 intersects the plurality of separation grooves of the unit cell 10 along the edge of the substrate 1. The outer peripheral groove 19 is formed by removing the heat-resistant resin layer 8 by a laser scribing method of irradiating a laser from the substrate 1 side and removing the laminated film 7 thereon. Laser scribing of the heat-resistant resin layer 8 is performed using a near ultraviolet to purple (wavelength 200 to 430 nm) laser suitable for resin processing, such as Nd: YAG laser triple wave (wavelength 355 nm) or XeF excimer laser (wavelength 353 nm). Use it. When the glass material of the substrate 1 is a material having a large absorption in the ultraviolet region of 350 nm or less, it is preferable to use a laser having a wavelength larger than 350 nm. Since the end portion of the laminated film 7 in the power generation region 30 is formed by laser scribing, mechanical deformation is hardly generated at the end portion, and the disorder of the structure of the laminated film 7 is small. Further, when the outer peripheral groove 19 is formed, the photoelectric conversion layer 4 and the second electrode layer 6 are removed using the second harmonic (wavelength 532 nm) of the Nd: YAG laser, and then the third harmonic of the Nd: YAG laser. The heat resistant resin layer 8 and the first electrode layer 2 may be removed in two steps using (wavelength 355 nm). By performing laser scribing using lasers having different wavelengths for each layer to be removed, the disorder of the structure of the laminated film 7 at the scribe end can be further prevented. Although the outer peripheral groove 19 is rectangular in FIG. 7B, the scribe line may be extended longer until the scribe line on each side of the rectangle extends outward from the corner of the rectangle.

  Note that when the heat-resistant resin layer 8 is subjected to laser scribing, a film composed mainly of carbon formed by decomposition of the resin may adhere to the end of the laminated film. In that case, the film containing carbon as a main component can be removed by performing laser scribing while supplying an oxidizing gas, or performing oxygen plasma treatment or oxidation after the processing.

  Further, as indicated by an arrow L in FIG. 7A, near ultraviolet to purple (wavelength 200 to 430 nm) light is emitted from the substrate 1 and the heat resistant resin layer 8 to the heat resistant resin layer 8 outside the outer peripheral groove 19. Irradiation is performed on the interface of the heat-resistant resin layer 8 to reduce the adhesive strength of the heat-resistant resin layer 8. When the glass material of the substrate 1 is a material having a large absorption in the ultraviolet region of 350 nm or less, light having a wavelength longer than 350 nm may be used. As such a light source, for example, a third harmonic (wavelength 355 nm) of an Nd: YAG laser can be used. When a laser is used as the light source, irradiation is performed on all the heat-resistant resin layers 8 outside the outer circumferential groove 19 as a condition of lower power density than when the outer circumferential groove 19 is formed by laser irradiation. Note that the heat-resistant resin layer 8 inside the outer circumferential groove 19 is not irradiated.

  Thereafter, as shown in FIG. 8, the laminated film 7 outside the outer peripheral groove 19 is peeled from the substrate 1 together with the heat-resistant resin layer 8 having a reduced adhesive force. As shown in the figure, the laminated film 7 in the outer peripheral region 40 is removed as a continuous peeling film 45 together with the heat-resistant resin layer 8. Thus, the thin film solar cell of the first embodiment shown in FIG. 2 is completed.

  FIG. 9 is a cross-sectional view illustrating the structure of a solar cell module using the thin film solar cell of the first embodiment. Wirings 15 are attached on the electrodes at both ends of the unit cells 10 connected in series, and a sealing material 21 is bonded with an adhesive layer 22 so as to cover all the unit cells 10. The sealing material 21 is a sheet such as polyethylene terephthalate (PET) or polyvinyl fluoride (PVF), and the adhesive layer 22 is an ethylene vinyl acetate copolymer resin (EVA) having a thickness of 0.1 to 0.6 mm, for example. It is. The wiring 15 is drawn out through a hole or the like of the sealing material 21 (not shown). In the thin film solar cell of the first embodiment, there is a region in which the height of the laminated film 7 from the substrate 1 is increased by the thickness of the heat-resistant resin layer 8 in the vicinity of the outer periphery of the power generation region 30. It is covered with the adhesive layer 22 that is sufficiently thicker than the heat-resistant resin layer 8 together with the outer peripheral region 40, and the back surface side of the sealing material 21 becomes almost smooth. Thus, even if the laminated film 7 is slightly higher in the vicinity of the outer periphery of the power generation region 30, there is almost no influence when the solar cell module is formed. Although not shown in the drawing, a terminal box is attached on the sealing material 21, and a frame or the like is attached to the outer periphery of the substrate 1.

  As described above, the unit cell 10 of the thin film solar cell having the laminated film 7 in which the first electrode layer 2, the photoelectric conversion layer 4, and the second electrode layer 6 are laminated is formed from a glass material. A plurality of thin film solar cells 100 disposed on a substrate 1. The manufacturing method includes a step of forming the heat-resistant resin layer 8 on the outer peripheral portion of the main surface of the substrate 1, a region in which the heat-resistant resin layer 8 in the outer peripheral portion is formed, and a region in which the heat-resistant resin layer 8 in the central portion is not formed. A step of laminating the laminated film 7 on the substrate 1 so as to cover the substrate 1 and a plurality of separation grooves (first groove 91, third groove 93) for dividing the laminated film 7 into a plurality of unit cells A separation groove forming step for continuously forming the heat-resistant resin layer 8 and the laminated film 7 on the heat-resistant resin layer 8 on which the separation grooves are formed are partially left and outside (outside as viewed from the center of the substrate 1). The outer peripheral film removing step including the step of removing the laminated film 7 on the side close to the edge of the substrate 1 together with the heat-resistant resin layer 8. Since the heat-resistant resin layer 8 is provided between the laminated film 7 and the substrate 1 in the vicinity of the outer peripheral portion close to the outer peripheral region 40 in the power generation region 30 to which the laminated film 7 adheres, There is a gap between the laminated film and the substrate 1 compared to the inner peripheral portion. In addition, since the laminated film 7 on the heat resistant resin layer 8 in which the separation groove is formed is partially left and the laminated film 7 on the outer side is removed together with the heat resistant resin layer 8, the laminated film 7 in the outer peripheral region 40 is removed. In this case, since the laminated film 7 to be removed is separated from the substrate 1 by the thickness of the heat-resistant resin layer 8, the influence of the removal processing hardly reaches the surface of the substrate 1. Therefore, it becomes easy to remove the laminated film 7 in the outer peripheral region 40 with almost no damage to the substrate 1. Since no damage or the like is generated on the substrate 1, the adhesion with the adhesive layer 22 is improved during modularization, and the sealing performance is improved. Further, since the laminated film 7 is removed together with the heat-resistant resin layer 8 by a laser scribing method, mechanical deformation is unlikely to occur at the end of the laminated film 7, and the laminated structure is maintained, so that short-circuiting is unlikely to occur at the end. When the laminated film 7 is removed by the laser scribing method with respect to the outer peripheral region 40 without the heat resistant resin layer 8, fine particles and the like of the laminated film 7 are likely to remain on the substrate 1, but in the method of the first embodiment, the heat resistant resin layer 8 is removed. At the same time, the fine particles of the laminated film 7 hardly remain on the substrate 1. For this reason, electrical insulation from the outside of the substrate 1 can be improved. Further, the first groove 91 and the third groove 93 that electrically separate the adjacent unit cells 10 are formed up to the laminated film in the region where the heat-resistant resin layer 8 is formed. Short circuit can be prevented.

  In the first embodiment, in the outer peripheral film removing step, the outer peripheral groove 19 intersecting with the separation groove is removed by removing the laminated film 7 on the outer peripheral side from the position of the end portion 29 on the inner peripheral side of the heat-resistant resin layer 8. Since the step of forming and the step of removing the laminated film 7 outside the outer peripheral groove 19 are performed separately, disorder of the structure of the end of the laminated film 7 can be prevented.

  Further, the outer peripheral groove 19 is made of an inorganic material because the heat-resistant resin layer 8 is irradiated with a laser beam having a wavelength absorbed by the heat-resistant resin layer 8 and the laminated film is removed together with the heat-resistant resin layer 8. Compared with the case where only the laminated film 7 is removed with laser light, processing can be performed with laser light having a low power density, and deterioration due to heat hardly occurs at the end of the laminated film 7.

  Further, in the step of forming the heat resistant resin layer 8, the end 29 of the heat resistant resin layer 8 has an inclined surface that becomes thinner as the central skin of the substrate 1 becomes thinner. In the step of forming the first groove 91 and the second groove 93), continuous separation grooves can be easily formed by a laser scribing method. In particular, if the inclined surface is an inclined surface that reaches the substrate surface, a steep step with the substrate 1 may be eliminated. When the heat-resistant resin layer 8 is formed with substantially the same thickness up to the end portion 29 and the end portion 29 is perpendicular to the main surface of the substrate 1, the first electrode layer 2 and the photoelectric conversion are also formed on the surface of the vertical end portion. Since the films of the layer 4 and the second electrode layer 6 are attached, the film thickness of each film viewed in the direction perpendicular to the substrate 1 is increased by the height of the end portion. Thus, it becomes difficult to process a continuous groove for each locally thick film. When the end portion is an inclined surface, the first electrode layer 2, the photoelectric conversion layer 4, and the second electrode layer 6 formed thereon have a small change in film thickness at the end portion 29 of the heat resistant resin layer 8. Therefore, it becomes easy to form the first groove 91, the second groove 92, and the third groove 93 continuously from the central region of the substrate where the heat-resistant resin layer 8 is not formed to the inclined surface of the heat-resistant resin layer 8. .

  Further, the step of removing the laminated film 7 outside the outer peripheral groove 19 together with the heat resistant resin layer 8 is performed in the near ultraviolet to purple (wavelength 200 to 430 nm) through the substrate 1 on the heat resistant resin layer 8 outside the outer peripheral groove 19. The process of reducing the adhesive strength between the heat-resistant resin layer 8 and the substrate 1 by irradiating light of a wavelength, and the heat-resistant resin layer 8 having reduced adhesive strength with the substrate 1 together with the laminated film 7 on the heat-resistant resin layer 8 Removing from the substrate 1. Therefore, the laminated film 7 can be removed as a continuous film all at once, and dust such as conductive fine particles is hardly generated. It is possible to prevent such conductive dust from adhering to the end of the laminated film 7 to cause a short circuit. Further, since generation of dust and reattachment thereof are almost eliminated, a cleaning process after processing can be omitted or simplified.

  In the first embodiment, the outer peripheral film removing step is a step of forming the outer peripheral groove 19 by laser scribing and a step of removing the laminated film 7 outside the outer peripheral groove 19 together with the peeling of the heat resistant resin layer 8. However, all the outer peripheral laminated films 7 may be removed together with the heat-resistant resin layer 8 by laser scribing. For example, the heat-resistant resin layer 8 is irradiated with a third harmonic wave (wavelength 355 nm) of an Nd: YAG laser to generate a decomposition evaporation phenomenon, and the laminated film 7 is removed together with the heat-resistant resin layer 8. In this case, the laser irradiation position is scanned in the outer peripheral region 40 to remove the laminated film 7 on the entire outer peripheral region 40. The order of laser scanning may be changed as appropriate, and formation of the separation groove 19 is not necessary. Even in this case, it is possible to manufacture a thin film solar cell that reduces damage to the glass substrate, reduces particles of the laminated film remaining on the substrate in the peripheral region, and prevents a short circuit at the end of the laminated film.

<Embodiment 2>
FIG. 10 is a top view of the thin-film solar cell 200 according to Embodiment 2 of the present invention. Thin-film solar cell 200 of the second embodiment is a thin-film solar cell having a heat-resistant resin 8 between the laminated film 7 near the outer periphery of the power generation region 30 and the substrate 1 as in the first embodiment. 40 is different in that the heat-resistant resin 48 having fine irregularities on the surface 40 remains.

  The manufacturing process of the thin-film solar cell according to the second embodiment includes the step of forming the heat-resistant resin layer 8 on the outer periphery of the substrate 1 as in the first embodiment, and the laminated film 7 on the substrate 1 on which the heat-resistant resin layer 8 is formed. A step of laminating and a plurality of separation grooves (first groove 91 and third groove 93) dividing the laminated film 7 into a plurality of unit cells are formed so as to continue up to the heat-resistant resin layer 8 on the outer peripheral portion of the substrate 1. An outer periphery including a separating groove forming step and a step of partially leaving the laminated film 7 on the heat-resistant resin layer 8 on which the separation groove is formed and removing the laminated film 7 on the outer side together with the heat-resistant resin layer 8 by a laser scribing method. And a film removal step. The outer peripheral film removing step is the same as that in the first embodiment until the outer peripheral groove 19 is formed by the laser scribing method, but the step of removing the laminated film 7 outside the outer peripheral groove 19 is different.

  FIG. 11 is a cross-sectional view illustrating a manufacturing process of the thin-film solar cell 200 according to Embodiment 2 of the present invention, and is a cross-sectional view illustrating a process of removing the laminated film 7 outside the outer peripheral groove 19. In the second embodiment, the step of removing the laminated film 7 outside the outer peripheral groove 19 together with the heat resistant resin layer 8 is performed by mechanically removing the laminated film 7 so that a part of the heat resistant resin layer 8 remains. Do. In the blast processing, for example, blast processing shown in FIG. In a state where the power generation region 30 and the middle of the outer peripheral groove 19 are covered with a mask 53 and protected, abrasive grains 52 are sprayed from the nozzle 51 to the outer peripheral region 40 to remove the laminated film 7. There is a heat resistant resin layer 8 between the laminated film 7 and the substrate 1, and blasting is performed until the heat resistant resin layer 8 is partially scraped. Thereby, the laminated film 7 in the outer peripheral region 40 can be completely removed. Then, as shown in FIG. 11B, the heat-resistant resin 48 having fine irregularities on the surface remains in the outer peripheral region 40.

  In the second embodiment, it is desirable to increase the thickness of the heat-resistant resin layer 8 to some extent so that the processing depth does not reach the substrate 1 during mechanical processing. When blasting is used as mechanical processing, the thickness of the heat-resistant resin layer 8 outside the outer peripheral groove 19 is desirably 20 microns or more, and more desirably 30 microns or more. In addition, it is desirable to use an insulating material as abrasive grains for blasting because there is no short circuit problem even if the abrasive grains stay on the surface of the heat-resistant resin 48 in the outer peripheral region 40 after processing. For example, alumina particles may be used as the insulating abrasive grains.

  FIG. 12 is a cross-sectional view of a solar cell module using a thin film solar cell in which the heat-resistant resin 48 in the outer peripheral region 40 of the second embodiment remains. Only the outer peripheral portion is different from the solar cell module shown in FIG. 9 of the first embodiment. Since there is a heat-resistant resin 48 having irregularities on the surface in the outer peripheral region 40, the surface area is increased, and the adhesive force with the adhesive layer 22 is increased as compared with the surface with the flat substrate 1.

  In the above, blast processing is used as mechanical processing, but brush processing for scraping the laminated film 7 with a brush, processing with a grindstone, or the like can also be used.

  According to the method of manufacturing the thin-film solar cell of the second embodiment, the outer peripheral groove 19 is formed by the laser scribing method, and the laminated structure at the end is maintained, so that a short circuit due to the end is less likely to occur. Since the laminated film 7 outside the outer peripheral groove 19 is removed by mechanical processing, the removal speed can be increased. Further, the laminated film 7 outside the outer peripheral groove 19 has a heat-resistant resin layer 8 between the substrate 1 and the substrate 1 is protected by the heat-resistant resin layer 8, so that the substrate 1 is less damaged.

<Embodiment 3>
Similarly to the first embodiment, the thin film solar cell of the third embodiment also has a gap between the laminated film 7 and the substrate 1 in the vicinity of the outer periphery of the power generation region 30, but between the laminated film 7 and the substrate 1. Part or all of the heat resistant resin 8 is removed.

  The manufacturing method of the thin film solar cell of the third embodiment is similar to the first embodiment in the step of forming the heat resistant resin layer 8 on the outer peripheral portion of the substrate 1 and the laminated film 7 on the substrate 1 on which the heat resistant resin layer 8 is formed. A step of laminating and a plurality of separation grooves (first groove 91 and third groove 93) dividing the laminated film 7 into a plurality of unit cells are formed so as to continue up to the heat-resistant resin layer 8 on the outer peripheral portion of the substrate 1. An outer periphery including a separating groove forming step and a step of partially leaving the laminated film 7 on the heat-resistant resin layer 8 on which the separation groove is formed and removing the laminated film 7 on the outer side together with the heat-resistant resin layer 8 by a laser scribing method. And a film removal step. The outer peripheral film removing step is the same as that in the first embodiment until the outer peripheral groove 19 is formed by the laser scribing method, but the step of removing the laminated film 7 outside the outer peripheral groove 19 is different.

  In the third embodiment, the heat-resistant resin layer 8 is etched to remove the laminated film 7 outside the outer peripheral groove 19. FIG. 13 is a top view for explaining the manufacturing process of the thin-film solar cell of Embodiment 3, and is a top view before the etching process in the step of removing the laminated film 7 outside the outer peripheral groove 19. As shown in FIG. 13, a plurality of intermittent grooves 61 are formed in the outer peripheral portion.

  FIG. 14 is a cross-sectional view for explaining the production process of the thin-film solar cell according to Embodiment 3, and FIG. 14 (a) shows the structure of the peripheral portion of the substrate in FIG. As shown in FIG. 14A, the intermittent groove 61 in the outer peripheral portion is formed by removing the heat resistant resin layer 8 and the laminated film 7 in the same manner as the outer peripheral groove 19. 14B, when the heat-resistant resin layer 8 is etched through the outer peripheral groove 19 or the plurality of grooves 61, the laminated film 7 thereon can be peeled off and removed. Unlike the first embodiment, in the third embodiment, the heat-resistant resin layer 8 is also formed on the side surface 11 of the substrate 1, so that the laminated film 7 on the side surface 11 can be easily removed. Thus, when the laminated film 7 is formed on the side surface 11 of the substrate 1, it is preferable to form the heat resistant resin layer 8 on the side surface 11 of the substrate 1 in the step of forming the heat resistant resin layer 8. When the laminated film 7 is not formed on the side surface 11 of the substrate 1, the heat resistant resin layer 8 on the side surface 11 of the substrate 1 is not necessary.

For example, oxygen plasma can be used for the etching. The heat-resistant resin layer 8 is oxidized and removed as a gas. Gases and chemicals used for etching may be appropriately selected depending on the material of the heat resistant resin layer 8. For example, the organic material in which the heat resistant resin layer 8 includes one or more of acrylic resin, polyimide resin, epoxy resin, olefin resin, and silicon resin. , Tetrafluoromethane (CF ₄ ), trifluoromethane (CHF ₃ ), hexafluoroethane (C ₂ F ₆ ), propane octafluoride (C ₃ F ₈ ), carbon tetrachloride (CCl ₄ ) A mixed gas of oxygen (O ₂ ) and any of sulfur hexafluoride (SF ₆ ), fluorine (F) -based gas, and chlorine (Cl) -based gas may be used as an etching gas. As these dry etching methods, a parallel plate RIE method or an atmospheric pressure plasma method can be used. When the heat-resistant resin layer 8 is an organic material such as polyimide resin, the etching rate can be easily adjusted by adjusting the supply gas ratio of oxygen gas, and the controllability is good. Further, wet cleaning such as high pressure water cleaning, megasonic cleaning, or brush cleaning may be performed after etching. A permeable film containing another material, for example, zinc oxide or indium tin oxide, is provided between the heat resistant resin layer 8 and the substrate 1, and the underlying permeable film is simultaneously etched when the heat resistant resin layer 8 is etched. You may be made to do. Also, if there are fine irregularities in the substrate, such as forming fine irregularities on the surface of the substrate or the permeable membrane, the adhesive strength of the heat resistant resin layer 8 will be good, and the heat resistant resin layer 8 will be peeled off before the outer peripheral film removing step. Can be prevented.

  The intermittent groove 61 is an opening that makes it easy for an etching agent or etching gas to reach the heat-resistant resin layer 8, and the shape may not be a groove. Since the outer peripheral groove 19 itself becomes an etching opening, the groove 61 is not essential. However, when a large number of the grooves 61 are formed as shown in FIG. 14A, the time for removing the heat-resistant resin layer 8 can be greatly reduced. Further, since the plurality of grooves 61 that are openings are formed intermittently as shown in FIG. 13, the laminated film 7 in the outer peripheral region 40 can be removed as a continuous peeling film 46, and the removal work of the peeled laminated film 7 is easy. It becomes. The plurality of grooves 61 may be formed by mechanical patterning such as a scribing method using a needle. Further, the grooves are not limited to intermittent grooves, and may be grooves connected to each other in a mesh shape.

  In the first to third embodiments described above, the end portion of the unit cell 10 in the power generation region 30 is the end portion 29 of the heat-resistant resin layer 8, but a separation groove in which the laminated film 7 is removed is provided slightly inside the end portion 29. Thus, the portion may be the end of the unit cell 10. In that case, the laminated film 7 on the heat-resistant resin layer 8 does not contribute to power generation. However, even in this case, damage to the glass substrate is reduced, and particles of the laminated film remaining on the substrate in the peripheral region are reduced. The effect of preventing the end short circuit is obtained. If there is a continuous conductive film in the immediate vicinity of the end portion between the unit cells 10 that are connected in series, a short circuit is likely to occur between the unit cells 10 through the conductive film. Since the separation film that is continuous with the separation groove of the unit cell 10 is formed in the laminated film 7 on the upper layer, a short circuit through the laminated film 7 on the heat resistant resin layer 8 is unlikely to occur.

  In the thin film solar cell formed in each of the above embodiments, the insulation resistance between the metal frame attached to the outer periphery of the substrate and the take-out wiring connected to the thin film solar cell is 1000 M ohm or more, and good insulation The characteristics were confirmed. Moreover, even if it was immersed in water after modularization, there was no change in the insulation characteristics, and good sealing performance was shown.

  According to the manufacturing method of the present invention, a highly reliable thin film solar cell can be easily manufactured.

DESCRIPTION OF SYMBOLS 1 Board | substrate, 2 1st electrode layer, 4 Photoelectric conversion layer, 6 2nd electrode layer, 7 Laminate film, 8 Heat-resistant resin layer, 10 Unit cell, 11 (Substrate) side surface, 15 Wiring, 19 Outer peripheral groove, 21 Sealing Material, 22 adhesive layer, 29 end of (heat-resistant resin layer), 30 power generation region, 40 outer peripheral region, 45, 46 release film, 48 heat-resistant resin layer, 51 nozzle, 52 abrasive grain, 53 mask, 61 groove, 91 first 1 groove, 92 2nd groove, 93 3rd groove, 100, 200 Thin film solar cell.

Claims (8)

A thin-film solar cell manufacturing method in which a plurality of unit cells of a thin-film solar cell having a laminated film obtained by laminating a first electrode layer, a photoelectric conversion layer, and a second electrode layer are disposed on a substrate made of a glass material,
Forming a heat-resistant resin layer on the outer periphery of the substrate;
Laminating the laminated film on the substrate on which the heat-resistant resin layer is formed;
A separation groove forming step of forming a plurality of separation grooves that divide the laminated film into a plurality of unit cells extending above the heat-resistant resin layer of the outer peripheral portion;
A peripheral film removing step of partially leaving the laminated film on the heat-resistant resin layer in which the separation groove is formed, and removing the laminated film on the outside together with the heat-resistant resin layer;
The manufacturing method of the thin film solar cell which has this. It is a manufacturing method of the thin film solar cell of Claim 1,
The outer peripheral film removing step includes a first step of forming the outer peripheral groove intersecting the separation groove by removing the laminated film on the heat resistant resin layer in which the separation groove is formed together with the heat resistant resin layer;
And a second step of removing the laminated film outside the outer peripheral groove together with the heat-resistant resin layer. It is a manufacturing method of the thin film solar cell of Claim 2,
In the first step, the outer peripheral groove is formed by a laser scribing method in which the laminated film is removed together with the heat-resistant resin layer. It is a manufacturing method of the thin film solar cell of any one of Claim 1 to 3,
In the step of forming the heat resistant resin layer, an inclined surface is formed at an end of the heat resistant resin layer,
In the separation groove forming step, the separation groove is continuously formed from a region where the heat resistant resin layer is not formed to the inclined surface of the heat resistant resin layer. It is a manufacturing method of the thin film solar cell of Claim 1 or 4,
In the method for manufacturing a thin-film solar cell, the outer peripheral film removing step irradiates a laser beam absorbed by the heat-resistant resin layer through the substrate to remove the laminated film together with the heat-resistant resin layer. It is a manufacturing method of the thin film solar cell of any one of Claim 2 to 4,
In the second step, the heat-resistant resin layer outside the outer peripheral groove is irradiated with light through the substrate to reduce the adhesive force between the heat-resistant resin layer and the substrate, and the adhesive force between the substrate and the substrate. Removing the heat-resistant resin layer having a reduced temperature from the substrate together with the laminated film thereon. It is a manufacturing method of the thin film solar cell of any one of Claim 2 to 4,
In the second step, the laminated film is mechanically processed and removed so that a part of the heat-resistant resin layer remains. It is a manufacturing method of the thin film solar cell according to any one of claims 2 to 4,
In the second step, the heat-resistant resin layer is etched to remove the laminated film on the heat-resistant resin layer.

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