JP2015170720A - Integrated thin film solar cell, and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an integrated thin film solar cell etc. which reduces a dead area generated by forming division grooves, thereby relatively expanding a power generation area and improving photoelectric conversion efficiency.SOLUTION: The method for manufacturing the integrated thin film solar cell comprises: a laminated film production step for producing a laminated film obtained by laminating a first electrode layer, a semiconductor layer, and a second electrode layer in this order on a substrate; a division groove formation step for forming plural division grooves parallel to each other by selectively removing the laminated film to expose the surface of the substrate; and an electrical conduction step for bringing the second electrode layer of the laminated film being one of adjacent cells divided by the division grooves and the first electrode layer of the laminated film being the other of the adjacent cells into conduction via the division grooves.

Description

  The present invention relates to an integrated thin film solar cell and a method for manufacturing the same.

  As a general structure of a thin film solar cell, a thin film including an electrode and a semiconductor layer is stacked on a substrate, and the stacked thin film is divided into a plurality of patterns (dividing grooves) to form a plurality of cells, and the cells are connected in series. Integrated structures connected to are known.

  For example, in the integrated thin film solar cell 100 shown in FIG. 1, the first electrode layer 120, the semiconductor layer 130, and the second electrode layer 140 are stacked on the substrate 110, and the stacked thin film is used as the first dividing groove 310. A plurality of cells are formed by being divided by the second dividing groove 320 and the third dividing groove 330. Each cell is connected in series to form an integrated structure.

  1A is a plan view of the integrated thin film solar cell, and FIG. 1B is a partially enlarged cross-sectional view taken along line AA (Y direction) of FIG. 1A. FIG. 1 shows an example in which the planar shape of the integrated thin film solar cell is rectangular, and the longitudinal direction when the integrated thin film solar cell is viewed in plan (when viewed from the light receiving surface side) is the X direction and the short direction. The hand direction is the Y direction and the thickness direction is the Z direction (the same applies to the following drawings).

  A general manufacturing method of the integrated thin film solar cell 100 will be described with reference to FIG. First, as shown in FIG. 2A, the first electrode layer 120 formed on the substrate 110 is divided by a first dividing groove 310 shown in the drawing. The first dividing groove 310 is formed linearly in the X direction, for example. Next, as illustrated in FIG. 2B, the semiconductor layer 130 is formed over the first electrode layer 120 and the first dividing groove 310.

  Thereafter, as shown in FIG. 2C, the semiconductor layer 130 is divided by a second dividing groove 320 that is substantially parallel to the first dividing groove 310. Next, as shown in FIG. 2D, the second electrode layer 140 is formed on the semiconductor layer 130 and the second dividing groove 320. Thereafter, as shown in FIG. 2 (e), each cell is connected in series by dividing the second electrode layer 140 by a third dividing groove 330 substantially parallel to the second dividing groove 320. An integrated thin film solar cell 100 (see FIG. 1) having an integrated structure is formed (see, for example, Patent Document 1).

JP 2011-165864 A

  However, in the conventional integrated structure forming method shown in FIG. 2, the first divided groove 310 is formed between the second divided groove 320 and the second divided groove 320 is formed. There is a step of forming the semiconductor layer 130 and the second electrode layer 140 between the three dividing groove 330 forming steps. That is, the first dividing groove 310, the second dividing groove 320, and the third dividing groove 330 need to be formed in separate steps. For this reason, there is a problem that three processes for forming the dividing grooves are required and the process becomes complicated.

  Further, in the conventional integrated structure forming method shown in FIG. 2, the distance between the first dividing groove 310 and the second dividing groove 320 and the distance between the second dividing groove 320 and the third dividing groove 330 are increased. As a result, a non-power generation area (dead area) that does not contribute to power generation becomes large.

  Specifically, when the semiconductor layer 130 is formed after forming the first dividing groove 310, the substrate 110 is deformed by the heat treatment in the film forming process of the semiconductor layer 130, and the first dividing groove 310 is undulated. (In the Y direction in FIG. 1) occurs.

Thereafter, when forming the second divided groove 320, the first divided groove 310 and the second divided groove 320 are not overlapped in consideration of the undulation of the first divided groove 310. It is necessary to form the second divided groove 320 at a certain distance from the first divided groove 310. Since the area between the first dividing groove 310 and the second dividing groove 320 is a dead area D ₁ (see FIG. 2E) that does not contribute to power generation, the dead area is constant by being separated by a certain distance. Generates an area.

Similarly, the second divided groove 320 and the third divided groove 330 are spaced apart from each other by a predetermined distance in consideration of the undulation of the second divided groove 320 when the third divided groove 330 is formed. It is necessary to form the divided grooves 330. Similarly, since the region between the second divided groove 320 and the third divided groove 330 is a dead area D ₂ (see FIG. 2E) that does not contribute to power generation, Here, a dead area is generated in a certain area.

  The present invention has been made in view of the above points, and manufacture of an integrated thin-film solar cell that improves the photoelectric conversion efficiency by reducing the dead area caused by the formation of the dividing grooves and relatively expanding the power generation area. It is an object to provide a method and the like.

  The manufacturing method of the integrated thin-film solar cell includes a stacked film forming step of forming a stacked film in which a first electrode layer, a semiconductor layer, and a second electrode layer are sequentially stacked on a substrate, and the stacked film Are selectively removed to expose the surface of the substrate to form a plurality of divided grooves parallel to each other, and a laminated film to be one of adjacent cells divided by the plurality of divided grooves It is a requirement to include a conduction step of conducting the second electrode layer and the first electrode layer of the laminated film that is the other of the adjacent cells through the plurality of dividing grooves.

  According to the disclosed technology, it is possible to provide a method for manufacturing an integrated thin film solar cell that reduces the dead area caused by the formation of the dividing groove and relatively increases the power generation area to improve the photoelectric conversion efficiency.

It is sectional drawing which illustrates a general integrated thin film solar cell. It is a figure which illustrates the manufacturing process of a general integrated type thin film solar cell. 1 is a cross-sectional view illustrating an integrated thin film solar cell according to a first embodiment. It is a figure which illustrates the manufacturing process of the integrated thin film solar cell which concerns on 1st Embodiment. It is sectional drawing which illustrates the integrated thin film solar cell which concerns on 2nd Embodiment. It is a figure which illustrates the manufacturing process of the integrated thin film solar cell which concerns on 2nd Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and the overlapping description may be abbreviate | omitted.

  In the following embodiments, a CIS-based integrated thin film solar cell will be described as an example, but the present invention is applicable to other than the CIS-based integrated thin film solar cell. Examples of integrated thin film solar cells to which the present invention can be applied include amorphous silicon thin film solar cells, microcrystalline silicon thin film solar cells, and compound thin film solar cells other than CIS.

  With a compound-based thin film solar cell other than CIS, for example, the light absorption layer contains copper (Cu), zinc (Zn), tin (Sn), and a chalcogen element (selenium (Se) or sulfur (S)). A CZTS thin film solar cell made of a compound, a CdTe thin film solar cell made of a compound whose light absorption layer contains cadmium (Cd) and tellurium (Te), and the like.

<First Embodiment>
[Structure of integrated thin-film solar cell according to first embodiment]
First, the structure of the integrated thin film solar cell according to the first embodiment will be described. FIG. 3 is a cross-sectional view illustrating the integrated thin film solar cell according to the first embodiment, and shows a cross section corresponding to FIG. The plan view of the integrated thin film solar cell according to the first embodiment is substantially the same as FIG.

  Referring to FIG. 3, the integrated thin film solar cell 10 is a CIS-based integrated thin film solar cell, and a first electrode layer 12, a semiconductor layer 13, and a second electrode layer 14 are formed on a substrate 11. A structure is formed in which stacked films are sequentially stacked. Hereinafter, each element constituting the integrated thin film solar cell 10 will be described.

  The substrate 11 is a portion serving as a base on which the first electrode layer 12, the semiconductor layer 13, and the second electrode layer 14 are formed. As the substrate 11, for example, a glass substrate such as blue plate glass or low alkali glass, a metal substrate such as stainless steel, a resin substrate such as epoxy resin, or the like can be used. The thickness of the substrate 11 can be, for example, about several tens of μm to several mm. However, when the substrate 11 is a conductor (for example, a metal substrate such as stainless steel), it is necessary to stack the first electrode layer 12 and the like via an insulating layer.

  The first electrode layer 12 is formed on the substrate 11. For example, molybdenum (Mo) can be used as the first electrode layer 12. As the first electrode layer 12, titanium (Ti), chromium (Cr), or the like having corrosion resistance against selenium (Se) or sulfur (S) may be used. The thickness of the first electrode layer 12 can be, for example, about several tens of nm to several μm. The first electrode layer 12 is a layer that becomes one electrode layer of the integrated thin film solar cell 10.

  The semiconductor layer 13 is a layer made of a p-type semiconductor, and is formed on the first electrode layer 12. The semiconductor layer 13 is a part that photoelectrically converts irradiated sunlight or the like. The electromotive force generated by the photoelectric conversion of the semiconductor layer 13 is, for example, as an electric current from the electrode ribbon (copper foil ribbon) attached to the first electrode layer 12 and the second electrode layer 14 with solder or the like. It can be taken out.

As the semiconductor layer 13, for example, a compound made of copper (Cu), indium (In), selenium (Se), copper (Cu), indium (In), gallium (Ga), selenium (Se), sulfur (S Or the like. In one example of the _compound, a _{CuInSe 2, Cu (InGa) Se} 2, Cu (InGa) (SSe) 2 or the like. The thickness of the semiconductor layer 13 can be, for example, about several μm to several tens of μm.

  A buffer layer (not shown) may be formed on the surface of the semiconductor layer 13. The buffer layer is a high-resistance layer having a function of preventing current leakage from the semiconductor layer 13. As a material of the buffer layer, for example, a zinc compound, zinc oxide (ZnO), zinc sulfide (ZnS), cadmium sulfide (CdS), indium sulfide (InS), or the like can be used. The thickness of the buffer layer can be, for example, about several nm to several hundred nm.

  The second electrode layer 14 is a transparent layer made of an n-type semiconductor and is formed on the semiconductor layer 13. As the second electrode layer 14, for example, a zinc oxide-based thin film (ZnO), an ITO thin film, or the like can be used. In the case of using a zinc oxide-based thin film (ZnO), the resistance can be reduced by adding boron (B), aluminum (Al), gallium (Ga), or the like as a dopant. The thickness of the second electrode layer 14 can be, for example, about several hundred nm to several tens of μm. The semiconductor layer 13 and the second electrode layer 14 form a pn junction. The second electrode layer 14 is a layer that becomes the other electrode layer of the integrated thin-film solar cell 10.

  A laminated film (a laminated film in which the first electrode layer 12, the semiconductor layer 13, and the second electrode layer 14 are laminated) formed on the substrate 11 includes a first divided groove 31 and a second divided groove 32. And the third dividing groove 33. The first dividing groove 31, the second dividing groove 32, and the third dividing groove 33 selectively remove the laminated film formed on the substrate 11 to remove the surface of the substrate 11 (the substrate 11 is a conductor). In this case, the patterns are three parallel patterns arranged in parallel at a predetermined interval along the X direction so that the surface of the insulating layer is exposed. The portions divided by the first dividing groove 31, the second dividing groove 32, and the third dividing groove 33 become cells. The width of each of the first dividing groove 31, the second dividing groove 32, and the third dividing groove 33 can be, for example, about several tens to several hundreds of micrometers.

  In addition, the parallel here is not parallel in a strict sense, but means approximately parallel within a range that does not impair the function of each dividing groove. That is, each dividing groove only needs to be able to divide the laminated film formed on the substrate 11, so that the function is not impaired even if another dividing groove is slightly inclined with respect to one dividing groove, and each dividing groove is completely The function is not impaired even if it is not a straight line. Including such a case, it shall be called parallel in this application.

  A laminated film of the first electrode layer 12, the semiconductor layer 13, and the second electrode layer 14 exists between the first dividing groove 31 and the second dividing groove 32 with an extremely thin width. Similarly, a laminated film of the first electrode layer 12, the semiconductor layer 13, and the second electrode layer 14 exists between the second dividing groove 32 and the third dividing groove 33 with an extremely thin width. ing. The two ultra-thin width portions are dead areas that do not contribute to power generation. The width of each dead area can be, for example, about several tens of μm.

  An insulating layer 15 is formed on the substrate 11 exposed in the first dividing groove 31. The insulating layer 15 is a layer for insulating the first electrode layer 12 of one laminated film adjacent to the first dividing groove 31 from the first electrode layer 12 of the other laminated film. Therefore, the insulating layer 15 has a thickness larger than that of the first electrode layer 12. As a material of the insulating layer 15, for example, an acrylic resin or glass can be used.

  The insulating layer 15 preferably has a higher resistance value than the semiconductor layer 13. Therefore, it is possible to more reliably insulate between the first electrode layers 12 of adjacent cells, and it is possible to reduce the leakage current generated between adjacent cells. For example, in the conventional integrated thin film solar cell 100 (see FIG. 1B), the first electrode layers 120 of adjacent cells are insulated by the semiconductor layer 130. In the integrated thin film solar cell 10, the leakage current generated between adjacent cells is higher than that of the conventional integrated thin film solar cell 100 by using the insulating layer 15 having a higher resistance than that of the semiconductor layer 130 (the semiconductor layer 13 is also equivalent). Can be reduced.

  On the insulating layer 15 in the first dividing groove 31, the second electrode layer 14 of one laminated film adjacent to the first dividing groove 31 and the second electrode layer 14 of the other laminated film are provided. A first conductor layer 16 is formed for electrical conduction. As a material of the first conductor layer 16, for example, a silver paste or other metal paste can be used.

  The surface of the first conductor layer 16 may be flush with the surface of the second electrode layer 14 as long as the second electrode layers 14 adjacent to the first dividing groove 31 can be made conductive. It may protrude from the surface of the second electrode layer 14 or may be recessed from the surface of the second electrode layer 14. Further, the first conductor layer 16 may protrude from the surface of the second electrode layer 14, and in this case, the first conductor layer 16 may be electrically connected to a second conductor layer 17 described later.

  A second conductor layer 17 is formed on the substrate 11 exposed in the second dividing groove 32. The second conductor layer 17 is a layer for electrically connecting the second electrode layer 14 of one laminated film adjacent to the second dividing groove 32 and the first electrode layer 12 of the other laminated film. . Therefore, the second conductor layer 17 has a thickness larger than the thickness obtained by adding the thickness of the first electrode layer 12 and the thickness of the semiconductor layer 13. As a material of the second conductor layer 17, for example, a silver paste or other metal paste can be used.

  The surface of the second conductor layer 17 may be flush with the surface of the second electrode layer 14, may protrude from the surface of the second electrode layer 14, or may be the surface of the second electrode layer 14. It may be deeper. Further, the second conductor layer 17 may protrude from the surface of the second electrode layer 14, and in this case, the second conductor layer 17 may be electrically connected to the first conductor layer 16.

  The second conductor layer 17 preferably has a lower resistance value than the second electrode layer 14. Therefore, the second electrode layer 14 and the first electrode layer 12 of the adjacent cell can be connected with low resistance, and the power generation efficiency of the integrated thin film solar cell 10 can be improved. For example, in the conventional integrated thin film solar cell 100 (see FIG. 1B), one second electrode layer 140 of an adjacent cell extends in the thickness direction so as to penetrate the semiconductor layer 130 and is adjacent. The other first electrode layer 120 of the cell to be connected is connected. In the integrated thin film solar cell 10, the second conductive layer 17 having a lower resistance than that of the second electrode layer 140 (the second electrode layer 14 is also equivalent) is used, so that the integrated thin film solar cell 100 has a higher resistance. Power generation efficiency can be improved.

  A third conductor layer 18 is formed on the substrate 11 exposed in the third dividing groove 33. The third conductor layer 18 is a layer for electrically connecting the first electrode layer 12 of one laminated film adjacent to the third dividing groove 33 and the first electrode layer 12 of the other laminated film. . However, the third conductor layer 18 should not conduct the second electrode layers 14 adjacent to the third dividing groove 33. Therefore, the third conductor layer 18 has a thickness less than the sum of the thickness of the first electrode layer 12 and the thickness of the semiconductor layer 13. As a material of the third conductor layer 18, for example, a silver paste or other metal paste can be used.

  As described above, the laminated film formed on the substrate 11 is divided into a plurality of cells by the first dividing groove 31, the second dividing groove 32, and the third dividing groove 33. The second electrode layer 14 of one adjacent cell and the first electrode layer 12 of the other cell include the first conductor layer 16, the second conductor layer 17, and the third conductor layer 18. Is conducting through. That is, adjacent cells are connected in series through the first conductor layer 16, the second conductor layer 17, and the third conductor layer 18 to form the integrated thin film solar cell 10. Yes.

[Method of Manufacturing Integrated Thin Film Solar Cell According to First Embodiment]
Next, a method for manufacturing the integrated thin film solar cell according to the first embodiment will be described. FIG. 4 is a diagram illustrating a manufacturing process of the integrated thin film solar cell according to the first embodiment. FIG. 4 shows a part of a cross section corresponding to FIG.

  First, as shown in FIG. 4A, a laminated film in which a first electrode layer 12, a semiconductor layer 13, and a second electrode layer 14 are sequentially laminated on a substrate 11 is formed.

  Specifically, as the substrate 11, for example, a glass substrate such as blue plate glass or low alkali glass, a metal substrate such as stainless steel, a resin substrate such as epoxy resin, or the like is prepared. Then, a first electrode layer 12 made of a transition metal such as molybdenum (Mo) is formed on the substrate 11 by, for example, sputtering, and the first electrode layer 12 is formed by, for example, sputtering, selenization, and sulfidation. A CIS-based semiconductor layer 13 is formed by a method or a vapor deposition method. However, when the substrate 11 is a conductor (for example, when it is a metal substrate such as stainless steel), it is necessary to form the first electrode layer 12 through an insulating layer.

  Further, a zinc oxide thin film (ZnO) doped with boron (B), gallium (Ga), aluminum (Al) or the like as a dopant on the semiconductor layer 13 by, for example, MOCVD or sputtering, or ITO (Indium Tin). Oxide) A transparent and low resistance film such as a thin film is formed as the second electrode layer 14. If necessary, a buffer layer may be formed on the surface of the semiconductor layer 13.

  Next, as shown in FIG. 4B, the laminated film formed on the substrate 11 is selectively removed to expose the surface of the substrate 11, and three parallel to each other arranged in parallel at a predetermined interval. The first dividing groove 31, the second dividing groove 32, and the third dividing groove 33, which are the above patterns, are formed. However, when the substrate 11 is a conductor, the laminated film is selectively removed to expose the insulating layer formed on the substrate 11, and the three patterns are arranged in parallel with each other at a predetermined interval. A first dividing groove 31, a second dividing groove 32, and a third dividing groove 33 are formed. Since the insulating layer is formed on the surface of the substrate 11, in the present application, it is expressed as “exposing the surface of the substrate” including the case where the insulating layer formed on the surface of the substrate 11 is exposed.

  Specifically, by irradiating the laminated film formed on the substrate 11 with laser light using, for example, a YAG laser, the portion of the laminated film irradiated with the laser light is removed, and the first film A dividing groove 31, a second dividing groove 32, and a third dividing groove 33 are formed. The width of each of the first dividing groove 31, the second dividing groove 32, and the third dividing groove 33 can be, for example, about several tens to several hundreds of micrometers. In place of laser light irradiation, a mechanical scribe using a needle or a sand blaster may be employed.

  The important point here is that the first divided groove 31, the second divided groove 32, and the third divided groove 33 are formed after all the laminated films on the substrate 11 are formed. More specifically, between the formation process of the first division groove 31 and the second division groove 32, and further, between the formation process of the second division groove 32 and the third division groove 33, the laminated film There is no process for forming a part of the film.

Therefore, unlike the prior art, there is no large undulation in the first dividing groove 31 when the second dividing groove 32 is formed. That is, since it is not necessary to consider the large undulation of the first dividing groove 31 in forming the second dividing groove 32, the distance between the first dividing groove 31 and the second dividing groove 32 is set to be the same as that of the prior art. It becomes possible to make it smaller than the method. As a result, to reduce the width of the dead area D ₁ of the first dividing grooves 31 generated between the second dividing groove 32, the area of the power generation area G ₁ and G ₂ can be increased. That is, power generation efficiency can be improved.

Similarly, with respect to the formation of the third dividing groove 33, it is not necessary to consider the large undulation of the second dividing groove 32 when forming the third dividing groove 33 as in the prior art. Therefore, the distance between the second dividing groove 32 and the third dividing groove 33 can be made smaller than that of the conventional method. As a result, to reduce the width of the dead area D ₂ generated across the second dividing groove 32 and the third dividing groove 33, the area of the power generation area G ₁ and G ₂ can be increased. That is, power generation efficiency can be improved. The width of each of the dead area _{D 1} and _{D 2,} for example, can be about several 10 [mu] m.

  In addition, although the 1st division groove 31, the 2nd division groove 32, and the 3rd division groove 33 may be formed separately, the 1st division groove 31, the 2nd division groove 32, and the 3rd A method of simultaneously forming the divided grooves 33 may be applied. For example, by preparing a pattern forming apparatus in which a tool for forming the first dividing groove 31, the second dividing groove 32, and the third dividing groove 33 (for example, a laser head) is integrated, the first division groove 31 is prepared. The dividing groove 31, the second dividing groove 32, and the third dividing groove 33 can be formed simultaneously.

  As described above, by forming the first dividing groove 31, the second dividing groove 32, and the third dividing groove 33 at the same time by using the pattern forming apparatus, even if waviness occurs during the formation, each dividing groove Since the intervals of are constant, each dividing groove has the same undulation. As a result, it is possible to further reduce the dead area by narrowing the interval between the divided grooves.

  More specifically, when the first dividing groove 31, the second dividing groove 32, and the third dividing groove 33 are individually formed, the undulation at the time of formation in the first dividing groove 31 (in the prior art) , Which is different from the undulation caused by heat treatment during film formation). In this case, in order to form the second dividing groove 32, it is necessary to increase a predetermined offset (a separation distance so as not to overlap the first dividing groove 31) in consideration of the undulation of the first dividing groove 31.

  On the other hand, when forming the 1st division groove 31, the 2nd division groove 32, and the 3rd division groove 33 simultaneously using a pattern formation device, it is the same wave in the same location in each division groove. Occurs. For this reason, it is possible to reduce a predetermined offset (interval between divided grooves) in consideration of individual undulations, and as a result, it is possible to further reduce the dead area.

Next, as shown in FIG. 4C, the insulating layer 15 is formed on the substrate 11 exposed in the first dividing groove 31. The insulating layer 15 can be formed by, for example, applying a solution containing an insulating acrylic resin, glass, or the like in the first dividing groove 31 and drying or annealing it. As another forming method, the insulating layer 15 may be formed by applying a photoresist solution containing an acrylic resin in the first dividing groove 31 and irradiating and developing light. As yet another forming method, the insulating layer 15 may be formed by applying a photocurable resin solution in the first dividing groove 31 and irradiating the solution with light. Insulating layer 15 includes a first electrode layer 12 of the power generation area G _1, is provided in order to insulate the first electrode layer 12 of the dead area D _1. Therefore, the film thickness of the insulating layer 15 only needs to be larger than the film thickness of the first electrode layer 12.

Next, as shown in FIG. 4D, the first conductor layer 16 is formed on the insulating layer 15. The first conductor layer 16 can be formed, for example, by applying a solution containing a conductor (for example, silver paste) on the insulating layer 15 and drying or annealing it. The first conductive layer 16 includes a second electrode layer 14 of the power generation area G _1, is provided in order to electrically connect the second electrode layer 14 of the dead area D _1. Therefore, the surface of the first conductor layer 16 may be flush with the surface of the second electrode layer 14 or may protrude from the surface of the second electrode layer 14 as long as it is conductive. The surface of the electrode layer 14 may be recessed.

Next, as shown in FIG. 4E, the second conductor layer 17 is formed on the substrate 11 exposed in the second dividing groove 32. The second conductor layer 17 can be formed by, for example, applying a solution containing a conductor (for example, silver paste) in the second divided groove 32 and drying or annealing it. The second conductive layer 17 is provided between the second electrode layer 14 of the dead area D _1, in order to conduct the first electrode layer 12 of the dead area D _2. Therefore, the film thickness of the second conductor layer 17 needs to be larger than the film thickness obtained by adding the film thickness of the first electrode layer 12 and the film thickness of the semiconductor layer 13. In other words, the second conductor layer 17 is formed so as to be in contact with the second electrode layer 14. The surface of the second conductor layer 17 may be flush with the surface of the second electrode layer 14, may protrude from the surface of the second electrode layer 14, or is recessed from the surface of the second electrode layer 14. But you can.

Next, as shown in FIG. 4 (f), the third conductor layer 18 is formed on the substrate 11 exposed in the third dividing groove 33. The third conductor layer 18 can be formed, for example, by applying a solution containing a conductor (for example, silver paste or the like) in the third dividing groove 33 and drying or annealing it. The third conductive layer 518 includes a first electrode layer 12 of the dead area D _2, causes conduction between the first electrode layer 12 of the power generation area G _2, and the second electrode layer 14 of the dead area D ₂ , it is provided to the second electrode layer 14 of the power generation area G ₂ becomes nonconductive.

Specifically, the third conductor layer 18 has a thickness less than the sum of the thickness of the first electrode layer 12 and the thickness of the semiconductor layer 13. Thereby, the third conductor layer 18 is not in contact with the second electrode layer 14 of the laminated film (dead area D ₂ and power generation region G ₂ ) adjacent to the third dividing groove 33, and the dead area D _2. it can be first conduction first electrode layer 12 and the first electrode layer 12 of the power generation area G ₂ in.

  The integrated thin film solar cell 10 shown in FIG. 3 is completed through the above steps. However, the first dividing groove 31, the second dividing groove 32, the third dividing groove 33, the insulating layer 15, the first conductor layer 16, the second conductor layer 17, and the third conductor layer 18 are not included. These sets are formed, and the necessary number of sets (one set less than the number of cells) is formed.

  In the above description of FIG. 4D to FIG. 4F, the method of individually forming the first conductor layer 16, the second conductor layer 17, and the third conductor layer 18 is shown. The first conductor layer 16, the second conductor layer 17, and the third conductor layer 18 may be formed simultaneously. Specifically, for example, a solution containing a conductor (for example, a silver paste) is applied to a portion where the first conductor layer 16, the second conductor layer 17, and the third conductor layer 18 are formed. . And the 1st conductor layer 16, the 2nd conductor layer 17, and the 3rd conductor layer 18 can be formed simultaneously by drying or annealing the apply | coated solution at once.

  As described above, in the first embodiment, all of the first divided groove, the second divided groove, and the third divided groove are stacked films (first electrode layer, semiconductor layer, first layer) on the substrate. After the second electrode layer is formed, the laminated film is removed. That is, between the step of forming the first divided groove and the step of forming the second divided groove, and further between the step of forming the second divided groove and the step of forming the third divided groove. However, there is no film-forming heat treatment step that exists in the prior art.

  Therefore, when forming the second dividing groove, the first dividing groove does not have a large undulation as in the prior art, so the second dividing groove is compared with the first dividing groove. It can be formed closer than in the prior art. As a result, the distance between the first dividing groove and the second dividing groove can be reduced as compared with the prior art, and the dead area can be reduced.

  Similarly, when the third divided groove is formed, the second divided groove does not have a large undulation as in the prior art, so the third divided groove is used as the second divided groove. On the other hand, it can be formed closer than in the prior art. As a result, the distance between the second divided groove and the third divided groove can be reduced as compared with the prior art, and the dead area can be reduced.

  Furthermore, the formation of the first divided groove, the second divided groove, and the third divided groove is a step of removing the laminated film, and the film to be removed is the same. That is, in forming each of the first divided groove, the second divided groove, and the third divided groove, it is not necessary to perform the process of removing each divided groove by a different method as in the prior art.

  That is, the first dividing groove, the second dividing groove, and the third dividing groove can be removed by the same method. Therefore, the tools for forming each divided groove are combined into one apparatus (for example, three laser heads for each divided groove (laser heads for removing the laminated film) are arranged), and each divided groove is formed at one time. It becomes possible. As a result, the distance between the divided grooves can be further reduced to further reduce the dead area, and the manufacturing process can be simplified.

  Further, when a plurality of power generation regions are formed, a plurality of devices in which tools for forming each divided groove are combined may be prepared, and a plurality of divided grooves may be formed at the same time. For example, in order to divide the power generation region into n, (n-1) devices combined with a tool are prepared, and a plurality of divided grooves are formed using the device, thereby generating the power generation region in one process. Can be divided into n.

<Second Embodiment>
In the first embodiment, an example in which three divided grooves are formed is shown, but in the second embodiment, an example in which two divided grooves are formed is shown. In the second embodiment, description of the same components as those of the already described embodiments may be omitted.

[Structure of integrated thin film solar cell according to second embodiment]
First, the structure of the integrated thin film solar cell according to the second embodiment will be described. FIG. 5 is a cross-sectional view illustrating an integrated thin film solar cell according to the second embodiment, and shows a cross section corresponding to FIG. The plan view of the integrated thin film solar cell according to the second embodiment is substantially the same as that shown in FIG.

  Referring to FIG. 5, the integrated thin film solar cell 10A has two dividing grooves (first dividing groove 31 and second dividing groove 34), and three dividing grooves (first dividing groove). It is different from the integrated thin film solar cell 10 which is the groove 31, the second dividing groove 32, and the third dividing groove 33).

  Specifically, in the integrated thin film solar cell 10 </ b> A, the laminated film formed on the substrate 11 is divided by the first dividing groove 31 and the second dividing groove 34. The first dividing groove 31 and the second dividing groove 34 are formed so as to selectively remove the laminated film formed on the substrate 11 so that the surface of the substrate 11 is exposed, along the X direction. These two patterns are arranged in parallel with each other and are parallel to each other. The width of each of the first dividing groove 31 and the second dividing groove 34 can be, for example, about several tens to several hundreds of μm. The first dividing groove 31 and the second dividing groove 34 may have the same width or different widths. For example, the width of the second dividing groove 34 may be wider than the width of the first dividing groove 31.

  A laminated film of the first electrode layer 12, the semiconductor layer 13, and the second electrode layer 14 exists between the first dividing groove 31 and the second dividing groove 34 with an extremely thin width. The ultra-thin width portion is a dead area that does not contribute to power generation. The width of the dead area can be, for example, about several tens of μm. As in the integrated thin film solar cell 10, the insulating layer 15 and the first conductor layer 16 are formed in the first dividing groove 31.

  A fourth conductor layer 19 is formed on the substrate 11 exposed in the second dividing groove 34. The fourth conductor layer 19 is a layer for electrically connecting the second electrode layer 14 of one laminated film adjacent to the second dividing groove 34 and the first electrode layer 12 of the other laminated film. . However, the fourth conductor layer 19 should not conduct the second electrode layers 14 adjacent to the second dividing groove 34.

  Therefore, the thickness of the fourth conductor layer 19 is the sum of the thickness of the first electrode layer 12 and the thickness of the semiconductor layer 13 on one end side of the second dividing groove 34 in contact with the inner wall on the first dividing groove 31 side. The film thickness is larger than that. The thickness of the second dividing groove 34 less than the sum of the thickness of the first electrode layer 12 and the thickness of the semiconductor layer 13 on the other end side in contact with the inner wall opposite to the first dividing groove 31. It is said that.

  The fourth conductor layer 19 has an inner wall opposite to the first dividing groove 31 of the second dividing groove 34 from one end side in contact with the inner wall of the second dividing groove 34 on the first dividing groove 31 side. The surface is inclined toward the other end side in contact with. As a material of the fourth conductor layer 19, for example, a silver paste or other metal paste can be used. Note that the fourth conductor layer 19 may protrude from the surface of the second electrode layer 14, and in this case, the fourth conductor layer 19 may be electrically connected to the first conductor layer 16.

  As described above, the laminated film formed on the substrate 11 is divided into a plurality of cells by the first dividing groove 31 and the second dividing groove 34. The second electrode layer 14 of one adjacent cell and the first electrode layer 12 of the other cell are electrically connected via the first conductor layer 16 and the fourth conductor layer 19. That is, adjacent cells are connected in series through the first conductor layer 16 and the fourth conductor layer 19 to constitute the integrated thin film solar cell 10A.

[Method for Manufacturing Integrated Thin-Film Solar Cell According to Second Embodiment]
Next, a manufacturing method of the integrated thin film solar cell according to the second embodiment will be described. FIG. 6 is a diagram illustrating a manufacturing process of the integrated thin film solar cell according to the second embodiment. FIG. 6 shows a part of a cross section corresponding to FIG.

  First, as illustrated in FIG. 6A, a stacked film in which a first electrode layer 12, a semiconductor layer 13, and a second electrode layer 14 are sequentially stacked on a substrate 11 is formed. The specific contents are the same as those described with reference to FIG.

  Next, as shown in FIG. 6 (b), the laminated film formed on the substrate 11 is selectively removed to expose the surface of the substrate 11, and two parallel pieces arranged in parallel at a predetermined interval are exposed. The first dividing groove 31 and the second dividing groove 34 which are the above patterns are formed. Specifically, by irradiating the laminated film formed on the substrate 11 with laser light using, for example, a YAG laser, the portion of the laminated film irradiated with the laser light is removed, and the first film A dividing groove 31 and a second dividing groove 34 are formed. The width of each of the first dividing groove 31 and the second dividing groove 34 can be, for example, about several tens to several hundreds of μm. The width of the second dividing groove 34 may be wider than the width of the first dividing groove 31. Note that mechanical scribing using a needle may be employed instead of laser light irradiation.

The first dividing groove 31 is the same as that shown in the first embodiment, but the second dividing groove 34 is the same as the second dividing groove 32 and the third dividing groove shown in the first embodiment. correspond to those obtained by integrating the dividing groove 33, the result is that eliminating the dead area D ₂ shown in the first embodiment.

  The first dividing groove 31 and the second dividing groove 34 are formed after the laminated film is formed on the substrate 11. Therefore, as in the first embodiment, a film forming process (heat treatment) for forming a laminated film is formed between the forming process of the first dividing groove 31 and the forming process of the second dividing groove 34. Process) does not exist.

Therefore, the second divided groove 34 can be formed at a position closer to the first divided groove 31 than in the prior art without considering the undulation due to the film forming process of the first divided groove 31. . As a result, as in the first embodiment, it is possible to the first dividing groove 31 of the dead area D ₁ of the between the second dividing grooves 34 be reduced as compared with the prior art, the power generation area G area ₁ and G ₂ can be increased. That is, power generation efficiency can be improved.

Further, in the second embodiment, it is possible to eliminate the dead area D ₂ which exist in the first embodiment, a decrease of a further dead area, the power generation efficiency can be further improved.

  Next, as shown in FIGS. 6C and 6D, the insulating layer 15 and the first conductor layer 16 are formed in the same manner as in FIGS. 4C and 4D. Then, as shown in FIG. 6E, the fourth conductor layer 19 is formed in the second dividing groove 34. The fourth conductor layer 19 can be formed, for example, by applying a solution containing a conductor (for example, silver paste or the like) in the second divided groove 34 and drying or annealing it.

The fourth conductor layer 19 is adjacent to the second conductor layer 17 in the second dividing groove 32 and the third conductor layer 18 in the third dividing groove 33 shown in the first embodiment. Corresponds to More specifically, the fourth conductor layer 19, causes conduction between the first electrode layer 12 of the second electrode layer 14 and the power generation region G ₂ of the dead area D _1, the dead area D ₁ It is provided to the two electrode layers 14 and the second electrode layer 14 of the power generation area G ₂ in the non-conductive.

Therefore, the fourth conductive layer 19, the dead area D ₁ side has a thickness in contact with the second electrode layer 14, the power generation region G ₂ side needs to be thick not in contact with the second electrode layer 14 is there. Fourth conductor layer 19, the dead area D ₁ side, may be a surface flush of the second electrode layer 14 may be projected from the surface of the second electrode layer 14, the second electrode layer It may be recessed from the surface of 14.

As a method for forming the fourth conductive layer 19, a solution having a predetermined viscosity with containing conductor, toward the upper side of the power generation area G ₂ on the lower side of the dead area D _1, in other words, on paper Apply (spray) diagonally from upper right to lower left. As a solution containing a conductor and having a certain viscosity, for example, a silver paste or other metal paste can be used.

Since the solution having a certain viscosity, will accumulate from the bottom of the dead area D ₁ gradually, the first electrode of the power generation area G ₂ solution surface from the second electrode layer 14 of the dead area D ₁ Inclined toward layer 12. By drying or annealing with the solution surface inclined, a fourth conductor layer 19 shown in FIG. 6E is formed. The first conductor layer 16 and the fourth conductor layer 19 may be formed at the same time as in the first embodiment.

Further, as another method for forming the fourth conductive layer 19, a solution having a predetermined viscosity with containing a conductor, a second electrode layer to the dead area D ₁ side of the fourth conductor layer 19 14 An amount that does not contact the second electrode layer 14 is applied to the power generation region G ₂ side in the second conductor layer 19. Thus, the solution surface is inclined toward the first electrode layer 12 of the power generation area G ₂ from the second electrode layer 14 of the dead area D _1. By drying or annealing with the solution surface inclined, a fourth conductor layer 19 shown in FIG. 6E is formed.

  The integrated thin film solar cell 10A shown in FIG. 5 is completed through the above steps. However, the first dividing groove 31, the second dividing groove 34, the insulating layer 15, the first conductor layer 16, and the fourth conductor layer 19 are set as one set, and these are set as necessary (based on the number of cells). (One less set).

Thus, in the second embodiment, by forming the second divided groove 34 in which the second divided groove 32 and the third divided groove 33 described in the first embodiment are integrated, In addition to the effects of the first embodiment, the following effects are further achieved. That is, since it is possible to eliminate the dead area D _2, a decrease of a further dead area, the power generation efficiency can be further improved.

  The preferred embodiment has been described in detail above. However, the present invention is not limited to the above-described embodiment, and various modifications and replacements are made to the above-described embodiment without departing from the scope described in the claims. Can be added.

10, 10A Integrated thin-film solar cell 11 Substrate 12 First electrode layer 13 Semiconductor layer 14 Second electrode layer 15 Insulating layer 16 First conductor layer 17 Second conductor layer 18 Third conductor layer 19 Fourth Conductor layer 31 First dividing groove 32, 34 Second dividing groove 33 Third dividing groove

Claims (15)

A laminated film forming step of forming a laminated film in which a first electrode layer, a semiconductor layer, and a second electrode layer are sequentially laminated on a substrate;
A split groove forming step of selectively removing the laminated film to expose the surface of the substrate and forming a plurality of split grooves parallel to each other;
The second electrode layer of the laminated film that is one of the adjacent cells divided by the plurality of divided grooves and the first electrode layer of the laminated film that is the other of the adjacent cells are divided into the plurality of divided grooves. A method of manufacturing an integrated thin-film solar cell. In the dividing groove forming step, a first dividing groove, a second dividing groove, and a third dividing groove that are parallel to each other are formed,
The conduction step includes
Forming an insulating layer having a thickness larger than the thickness of the first electrode layer on the substrate exposed in the first dividing groove;
In the first division groove, a first conductor layer for electrically connecting the second electrode layer of one laminated film adjacent to the first division groove and the second electrode layer of the other laminated film is provided. A first conductor layer forming step to be formed;
Forming a second conductor layer having a thickness larger than the sum of the thickness of the first electrode layer and the thickness of the semiconductor layer on the substrate exposed in the second dividing groove; A conductor layer forming step,
Forming a third conductor layer having a thickness less than the sum of the thickness of the first electrode layer and the thickness of the semiconductor layer on the substrate exposed in the third dividing groove; A method for producing an integrated thin film solar cell according to claim 1, comprising a conductor layer forming step.   The method for manufacturing an integrated thin-film solar cell according to claim 2, wherein a laminated film is present between the second divided groove and the third divided groove.   4. The integrated thin film solar cell according to claim 2, wherein the second conductor layer is formed by applying a solution containing a conductor in the second dividing groove and drying or annealing the solution. Production method.   5. The integration according to claim 2, wherein the third conductor layer is formed by applying a solution containing a conductor in the third dividing groove and drying or annealing the solution. Type thin film solar cell manufacturing method. In the dividing groove forming step, a first dividing groove and a second dividing groove that are parallel to each other are formed,
The conduction step includes
Forming an insulating layer having a thickness larger than the thickness of the first electrode layer on the substrate exposed in the first dividing groove;
In the first division groove, a first conductor layer for electrically connecting the second electrode layer of one laminated film adjacent to the first division groove and the second electrode layer of the other laminated film is provided. A first conductor layer forming step to be formed;
The thickness of the first electrode layer and the thickness of the semiconductor layer on the substrate exposed in the second dividing groove and on one end side of the second dividing groove in contact with the inner wall on the first dividing groove side And the thickness of the first electrode layer on the other end side of the second divided groove that is in contact with the inner wall opposite to the first divided groove and the thickness of the first divided electrode A method for producing an integrated thin-film solar cell according to claim 1, further comprising: a fourth conductor layer forming step of forming a fourth conductor layer having a thickness less than the sum of the thicknesses of the semiconductor layers.   The fourth conductor layer is coated with a predetermined viscous solution containing a conductor in the second dividing groove, and the solution is applied in a state where the surface is inclined from the one end side toward the other end side. The method for producing an integrated thin-film solar cell according to claim 6, wherein the method is formed by drying or annealing.   8. The integrated thin film solar according to claim 2, wherein the insulating layer is formed by applying a solution containing an insulator in the first dividing groove and drying or annealing the solution. Battery manufacturing method.   The integrated thin-film solar according to any one of claims 2 to 8, wherein the first conductor layer is formed by applying a solution containing a conductor on the insulating layer and drying or annealing the solution. Battery manufacturing method.   The method for manufacturing an integrated thin film solar cell according to claim 2, wherein the insulating layer has a resistance value higher than that of the semiconductor layer. A substrate,
A laminated film in which a first electrode layer, a semiconductor layer, and a second electrode layer are sequentially laminated on the substrate;
A first divided groove, a second divided groove, and a third divided groove that are formed so as to selectively remove the laminated film and expose the surface of the substrate;
An insulating layer having a thickness greater than the thickness of the first electrode layer formed on the substrate exposed in the first dividing groove;
A first conductor formed in the first dividing groove and electrically connecting the second electrode layer of one laminated film adjacent to the first dividing groove and the second electrode layer of the other laminated film Layers,
A second conductor layer formed on the substrate exposed in the second dividing groove and having a thickness greater than the sum of the thickness of the first electrode layer and the thickness of the semiconductor layer;
A third conductor layer formed on the substrate exposed in the third dividing groove and having a thickness less than the sum of the thickness of the first electrode layer and the thickness of the semiconductor layer; Integrated thin film solar cell.   The integrated thin film solar cell according to claim 11, wherein a laminated film is present between the second divided groove and the third divided groove. A substrate,
A laminated film in which a first electrode layer, a semiconductor layer, and a second electrode layer are sequentially laminated on the substrate;
A first dividing groove and a second dividing groove which are formed so as to selectively remove the laminated film and expose the surface of the substrate;
An insulating layer having a thickness larger than the thickness of the first electrode layer formed on the substrate exposed in the first dividing groove;
A first conductor formed in the first dividing groove and electrically connecting the second electrode layer of one laminated film adjacent to the first dividing groove and the second electrode layer of the other laminated film Layers,
The thickness of the first electrode layer and the semiconductor layer are formed on the substrate exposed in the second dividing groove and are in contact with the inner wall of the second dividing groove on the first dividing groove side. And the thickness of the first electrode layer on the other end side of the second divided groove in contact with the inner wall opposite to the first divided groove. And a fourth conductor layer having a thickness less than the sum of the thicknesses of the semiconductor layers.   The integrated thin film solar cell according to claim 13, wherein a surface of the fourth conductor layer is inclined from the one end side toward the other end side.   The integrated thin film solar cell according to claim 11, wherein the insulating layer has a higher resistance value than the semiconductor layer.

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