JP2006185979A - Thin-film solar battery module and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently manufacture a thin-film solar battery module while securing the insulation property by dividing a metal substrate for each thin-film solar battery cell. <P>SOLUTION: The thin-film solar battery cell 5 is made by forming a lower conductive layer 2, semiconductor layer 3, and upper transparent conductive layer 4 in order on the metal substrate 1. A plurality of such thin-film solar battery cells 5 are connected in series to fabricate the thin-film solar battery module. In the thin-film solar battery module, the metal substrate 1 is divided for each thin-film solar battery cell 5, and the upper transparent conductive layer 4 of one of the adjacent thin-film solar battery cells 5 is connected to the lower conductive layer 2 and/or metal substrate 1 of the other thin-film solar battery cell 5. Since the substrate is made of a metal, no damage such as deformation and melting occurs to the substrate even under a high temperature at the time of film formation. The lower conductive layer 2 has not always to be formed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

  There is a thin film solar cell module having a structure in which solar cell unit cells (hereinafter referred to as solar cells) are connected in series to a conventional thin film solar cell. For example, in the thin film solar cell module disclosed in Patent Document 1, as shown in FIG. 8, a semiconductor junction layer 3 a, a window layer 3 b, and an upper electrode layer having a pn junction with a lower electrode layer 2 on an insulating substrate 1. 4 are stacked in this order to form a thin film solar cell. Each layer 2, 3a, 3b, 4 is divided by groove portions L1, L2, L3, and a plurality of solar cells 5 divided by these groove portions L1, L2, L3 are formed. Adjacent solar cells 5 are connected in series when the upper electrode layer 4 formed in the groove L2 is in contact with the lower electrode layer 2. Since it is necessary to electrically isolate each thin-film solar battery cell 5 except for the serial connection portion, the above-described insulating substrate 1 is used.

This thin film solar cell module is manufactured by repeating thin film formation and thin film groove processing on a single substrate. This will be described with reference to FIG.
First, a metal film such as a Mo film is formed on an insulating substrate 1 such as a glass plate to form a lower electrode layer 2 (FIG. 9A), and the lower electrode layer 2 is formed in a strip shape by a groove L1 by a laser scribing method. (FIG. 9B). Next, a p-type semiconductor layer such as a CuInSe ₂ thin film and an n-type semiconductor layer such as a CdS thin film are formed so as to cover the lower electrode layer 2 to form a semiconductor bonding layer 3a, and ZnO is formed on the semiconductor bonding layer 3a. A layer or the like is formed to form the window layer 3b (FIG. 9C). The semiconductor film composed of the semiconductor bonding layer 3a and the window layer 3b is divided into strips at the groove L2 (FIG. 9D), and a transparent conductive film such as an ITO thin film is formed thereon to form the upper electrode layer 4. (FIG. 9E), the upper electrode layer 4 is patterned and divided into strips at the groove L3 (FIG. 9F).
Japanese Patent Laid-Open No. 11-224958 (page 4-5, FIGS. 1 and 2)

  Thin-film solar cells can generate power with a thickness of several micrometers, making them thinner and lighter. To reduce the thickness of substrates for these purposes, thin glass substrates, resin films, and insulating layers are used on the surface. A formed metal substrate or the like has been used.

However, CuInSe ₂ thin film used as a p-type semiconductor layer needs to be heated to about 600 ° C. at the time of film formation. Therefore, if a thin glass substrate is used, it is greatly deformed, and a resin film substrate is used. When a metal substrate that is melted and has an insulating layer formed on the surface is used, there is a problem that cracks are generated in the insulating layer due to a difference in thermal expansion coefficient from the metal substrate.

  In addition, thin film solar cell modules are manufactured by repeating thin film formation and groove processing on a single substrate as described above, but the current situation is that each substrate is processed one by one. There was a problem of low. It is possible to apply a so-called roll-to-roll method in which a conductive substrate such as a metal substrate is run and sequentially processed in the running path. However, as described above, an insulating layer is not formed on the substrate surface. In other words, there was a problem that productivity was lowered.

  This invention solves the said problem, and it aims at ensuring efficient insulation and ensuring a thin film solar cell module and a thin film photovoltaic cell.

  In order to solve the above problems, the thin film solar cell module of the present invention is a thin film solar cell module in which a plurality of thin film solar cells in which at least a semiconductor layer and an upper transparent conductive layer are sequentially formed on a metal substrate are connected in series. A metal substrate is separated for each thin film solar cell, and the upper transparent conductive layer of one thin film solar cell adjacent to each other is connected to the metal substrate of the other thin film solar cell.

  A lower conductive layer may be formed on a metal substrate, and the upper transparent conductive layer of one thin film solar cell adjacent to each other may be connected directly or via the lower conductive layer to the metal substrate of the other thin film solar cell. . This is a particularly advantageous structure when the semiconductor layer includes a chalcopyrite semiconductor layer.

  The method for manufacturing a thin film solar cell module of the present invention is a method for manufacturing a thin film solar cell module in which a plurality of thin film solar cells are connected in series, and a step of forming a semiconductor layer on a metal substrate in which through grooves are formed in parallel. Removing a semiconductor layer on one side of the through-groove to form a contact groove; forming an upper transparent conductive layer on the semiconductor layer and in the contact groove; and upper transparent conductive on one side of the through-groove A step of forming a separation groove for separating the layer from the through groove at a predetermined interval; and a series of the upper transparent conductive layer separated from each other by the separation groove and formed in the contact groove to the metal substrate in series. A step of coating a plurality of connected thin-film solar cells with a translucent resin including the metal substrate, and a method of arranging the through grooves in the resin sealing body coated with the translucent resin Cut so as to pass through the end portion of the through groove along, characterized in that it comprises a step of dividing the metallic substrate for each thin-film solar batteries.

  It is convenient to use a band-shaped metal substrate in which through grooves are formed at predetermined intervals along the longitudinal direction of the substrate. A lower conductive layer may be formed on the metal substrate prior to the semiconductor layer.

  The thin film solar cell module of the present invention ensures insulation by dividing a metal substrate for each thin film solar cell, and cracks in the insulating layer that have occurred in the conventional one in which an insulating layer is provided on the substrate surface The problem can be avoided.

  Since the method for manufacturing a thin film solar cell module of the present invention uses a metal substrate, the substrate is deformed or melted even at a high temperature when forming a semiconductor layer, for example, a high temperature when forming a semiconductor layer having a chalcopyrite structure. Since no damage such as this occurs and it is not necessary to provide an insulating layer, productivity and quality can be improved. When using a band-shaped metal substrate, the so-called roll-to-roll method can be applied for thin film formation, etc., and productivity should be improved compared to a sheet-like method in which substrates are processed one by one. Can do.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1A is a top view showing the structure of the first thin film solar cell module of the present invention, and FIG. 1B is a cross-sectional view of the thin film solar cell module.

  1A and 1B, on a metal substrate 1 such as a stainless steel substrate, a lower conductive layer 2 made of a metal film such as a Mo film, a semiconductor junction layer having a pn junction, and a window layer such as a ZnO film. A thin film solar cell is formed by stacking a semiconductor layer 3 and an upper transparent conductive layer 4 such as an ITO film. This thin-film solar cell is provided with a through groove P1 that divides the metal substrate 1 and the lower conductive layer 2 at predetermined intervals along the substrate longitudinal direction, and a separation groove P2 that divides the upper transparent conductive layer 4 and the semiconductor layer 3. A plurality of thin-film solar cells 5 divided by the through grooves P1 and the separation grooves P2 are formed. The upper electrode layer 4 formed in the separation groove P2 is in contact with the lower electrode layer 2, and a thin film solar cell module in which adjacent thin film solar cells 5 are connected in series is configured. In order to protect the entire thin-film solar cell module, a laminate layer 6 that covers the upper and lower surfaces (here, the side surfaces) is provided.

The method for manufacturing the thin-film solar cell module will be described with reference to the manufacturing process sectional view shown in FIG. 2 and the flowchart shown in FIG.
First, as shown in FIG. 2 (a), a technique such as press working, laser processing, etching, or the like is performed on a band-shaped metal substrate 1 with a through groove P1 for dividing the metal substrate 1 at predetermined intervals along the longitudinal direction of the substrate. Formed by. The predetermined interval is an interval corresponding to the desired width of the thin-film solar battery cell. For example, if the metal substrate 1 has a thickness of 0.1 mm and a width (dimension in the short side) of 100 mm, the through groove P1 has a dimension in the short side direction of the substrate of about 90 mm and a dimension in the longitudinal direction of the substrate of 100 μm or less. They are formed at intervals of about 3 to 6 mm (step S10 in FIG. 3).
Next, as shown in FIG. 2B, a metal thin film such as a Mo film is formed on the surface of the metal substrate 1 by a sputtering method to form the lower conductive layer 2. At this time, the lower conductive layer 2 is not formed in the through groove P1, but a through groove P1 ′ having the same dimensions as the through groove P1 is provided (step S11).
Next, as shown in FIG. 2C, a backup plate 7 is attached to the back surface of the metal substrate 1, and a semiconductor layer 3 is formed on the lower conductive layer 2 of the metal substrate 1 supported by the backup plate 7 (semiconductor). The layer 3 also covers the back-up plate 7 corresponding to the through groove P1 portion of the metal substrate 1 (step S12), and the semiconductor layer 3 adjacent to the through groove P1 is removed as shown in FIG. Processing is performed to form a contact groove P3 parallel to the through groove P1 on one side of the through groove P1 (step S13).

The semiconductor layer 3 includes a semiconductor junction layer having a pn junction composed of a p-type semiconductor layer and an n-type semiconductor layer, and a window layer such as ZnO. For the p-type semiconductor layer, a chalcopyrite structure I-III-VIb group semiconductor, for example, a thin film of CuInSe _{2 or} the like is used. The CuInSe ₂ thin film is formed by vapor deposition or sputtering. The substrate temperature needs to be as high as about 600 ° C. at the time of film formation, but since the metal substrate 1 is used, the deformation of the substrate can be suppressed as compared with the conventional method using a glass substrate. It is also possible to raise the temperature of the CuInSe ₂ film and improve the crystallinity of the CuInSe ₂ film. For the n-type semiconductor layer, II-VI group compounds such as CdS or ZnO or ZnS are used. A chemical precipitation method or the like is used for forming the n-type semiconductor layer.

  The contact groove P3 is formed by removing the semiconductor layer 3 by mechanical patterning until the lower conductive layer 2 is exposed. The mechanical patterning is a method of mechanically removing the film using a tool having a width substantially equal to the width of the contact groove P3. For example, the contact groove P3 is formed with a width of 100 μm or less at an interval of 100 μm or less with respect to the through groove P1.

  Next, as shown in FIG. 2E, the upper transparent conductive layer 4 is formed on the semiconductor layer 3 and in the contact groove P3 (step S14), and then a position adjacent to the contact groove P3 (in the through groove P1). The upper transparent conductive layer 4 and the semiconductor layer 3 on the opposite side are removed by a predetermined width to form a cell separation groove P2 parallel to the contact groove P3 (step S15).

  Since the upper transparent conductive layer 4 is required to have translucency and conductivity, an ITO film or the like is formed by a sputtering method. The formed upper transparent conductive layer 4 is electrically connected to the lower conductive layer 2 through the contact groove P3.

The cell separation groove P2 is formed by removing the semiconductor layer 3 and the upper transparent conductive layer 4 by mechanical patterning until the lower conductive layer 2 is exposed. In this case, the lower conductive layer 2 is a Mo film, the semiconductor layer 3 is a CuInSe ₂ / CdS / ZnO laminated film, and the upper transparent conductive layer 4 is an ITO film, and the Mo film, the CuInSe ₂ film, Therefore, the semiconductor layer 3 and the upper transparent conductive layer 4 can be selectively removed. However, the cell separation groove P2 can exhibit the same effect even if only the upper transparent conductive layer 4 is removed.

Next, as shown in FIG. 2F, the backup plate 7 is removed.
Up to this step, the thin film solar cell 5 having a laminated structure of the lower conductive layer 2, the semiconductor layer 3, and the upper transparent conductive layer 4 for each region where the metal substrate 1 is partitioned by the through groove P1 (see FIG. 1). Is formed. In each thin film solar cell 5, the upper transparent conductive layer 4 is separated by the cell separation groove P <b> 2, and the upper transparent conductive layer 4 of one adjacent thin film solar cell 5 is the lower conductive layer 2 of the other thin film solar cell 5. Are electrically connected at the position of the contact groove P3. An antireflection layer such as MgF may be further formed on the upper transparent conductive layer 4 before or after removing the backup plate 7.

Next, as shown in FIG. 2G, the whole of the metal substrate 1 and each layer thereon is covered with a laminate layer 6 of a translucent resin. This increases the mechanical strength and protects against environmental influences such as humidity. The laminate layer 6 is formed by placing a back film such as a tedla film on the back side of the metal substrate 1 and then applying a sealing resin such as EVA (Ethylene-Vinyl Acetate copolymer) covering the front side of the metal substrate 1. (Step S16).
Finally, the metal substrate 1 is divided for each thin film solar cell by cutting the end portion along the substrate longitudinal direction of the resin sealing body covered with the laminate layer 6 into the through groove P1 by the cutting line 8. A completed product of the thin-film solar cell module as shown in FIG. 2 (h) is obtained (step S17).

  Such a thin film solar cell module includes a thin film solar cell 5 having a structure in which electric energy generated by the semiconductor layer 3 is extracted from a lower electrode (consisting of the lower conductive layer 2 and the metal substrate 1) and an upper transparent conductive layer 4. They are connected in series.

Since the metal substrate 1 is finally divided by the through-groove P1, an insulating layer is unnecessary, and the substrate is damaged even when the film forming temperature is increased when forming a p-type semiconductor layer such as CuInSe ₂ There is no. Therefore, the step of forming the insulating layer can be omitted as compared with the conventional insulating metal substrate, and the metal substrate 1 itself functions as a conductive layer, so the thickness of the lower conductive layer 2 can be reduced, and the amount of material used The number of processes can be reduced, and the cost can be reduced.

In addition, for example, in step S11 for forming the lower conductive layer 2, the metal substrate 1 is applied with a so-called roll-to-roll method in which a thin film formation or the like is performed while being fed out from a rolled state and then wound again. It is also possible. According to this, since processing such as thin film formation can be performed continuously, productivity can be improved as compared with a sheet-like method in which substrates are processed one by one.
(Embodiment 2)
FIG. 4 is a partially enlarged sectional view showing the structure of the second thin film solar cell module of the present invention.

The thin film solar cell module of the second embodiment is different from the thin film solar cell module of the first embodiment described above in that the lower conductive layer is not formed and the upper transparent conductive layer 4 is directly connected to the metal substrate 1. It is a point. From the method described in the first embodiment, it is possible to manufacture in the same manner only by omitting the step of forming the lower conductive layer 2 (step S11).
(Embodiment 3)
FIG. 5 is a partially enlarged sectional view showing the structure of the third thin film solar cell module of the present invention.

  The thin film solar cell module of Embodiment 3 is different from the thin film solar cell module of Embodiment 1 described above in that the lower conductive layer 2 is not formed on one side of the through groove P1, and the upper transparent conductive layer 4 is directly The point is that it is connected to the metal substrate 1. After the step of forming the through groove P1 in the band-shaped metal substrate 1 in the first embodiment (FIG. 2A, step S10), as shown in FIG. 6A, on the metal substrate 1 on one side of the through groove P1 The resist 2a can be dissolved as shown in FIG. 6 (b) after the step of applying the resist 2a to the substrate and further the step of forming the lower conductive layer 2 ((FIG. 2 (b), step S11). It can be similarly manufactured by adding a step of removing the resist 2a and the lower conductive layer 2 thereon using a solution.

The structures of Embodiments 2 and 3 are applied when the metal substrate 1 has better adhesion or contact resistance with the upper transparent conductive layer 4 than the lower conductive layer.
(Embodiment 4)
A method of dividing the thin film solar cell module of the present invention into cells will be described with reference to FIG. Detailed description of portions using the same materials and forming methods as those in the first embodiment will be omitted.

First, as shown in FIG. 7A, a through-groove P1 for dividing the metal substrate 1 at predetermined intervals along the longitudinal direction of the substrate is formed in the band-shaped metal substrate 1.
Next, as shown in FIG. 7B, the lower conductive layer 2, the semiconductor layer 3, and the upper transparent conductive layer 4 are formed on the metal substrate 1. At this time, each layer is not formed in the through groove P1. An antireflection layer such as MgF may be further formed on the upper transparent conductive layer 4.

  Next, as shown in FIG.7 (c), the metal substrate 1 and the whole each layer on it are covered with the laminate layer 6 of translucent resin. This increases the mechanical strength and protects against environmental influences such as humidity.

  Finally, as shown in FIG. 7 (d), the end of the resin sealing body covered with the laminate layer 6 along the longitudinal direction of the substrate is cut to the inside of the through groove P1 by the cutting line 8, and inside the through groove P1. By cutting along the substrate width direction, the individual thin film solar cells 5 are divided as shown in FIG.

  The thin film solar cell 5 formed by such a method has a structure in which a flat lower conductive layer 2, a semiconductor layer 3, and an upper transparent conductive layer 4 are provided on a metal substrate 1, and the electric energy generated by the semiconductor layer 3 is generated. It can be taken out from the lower electrode (consisting of the lower conductive layer 2 and the metal substrate 1) and the upper transparent conductive layer 4.

  In this thin film solar cell manufacturing method, it is also possible to apply a roll-to-roll method, thereby improving productivity as compared with a sheet-like method in which substrates are processed one by one. . In the roll-to-roll method, when a strip-shaped substrate without the through groove P1 is used, the substrate is deformed or peeled off at the cut portion when the thin film solar cell 5 is divided, but the through groove P1 exists. The damage to the film and the substrate can be extremely reduced.

  The present invention is useful for manufacturing a thin film solar cell module using a metal substrate.

(A) Top view and (b) Cross section showing the structure of the first thin film solar cell module of the present invention 1 is a top view illustrating a method for manufacturing the thin film solar cell module of FIG. The flowchart explaining the manufacturing method of the thin film solar cell module of FIG. The partially expanded sectional view which shows the structure of the 2nd thin film solar cell module of this invention The partially expanded sectional view which shows the structure of the 3rd thin film solar cell module of this invention FIG. 5 is a top view illustrating a method for manufacturing the thin film solar cell module of FIG. Top view and cross-sectional view for explaining a method for manufacturing a thin-film solar battery cell Sectional view showing the structure of a conventional thin film solar cell Process sectional drawing which shows the manufacturing method of the conventional thin film solar cell

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal substrate 2 Lower conductive layer 3 Semiconductor layer 4 Upper transparent conductive layer 5 Thin film photovoltaic cell 6 Laminate layer P1 Through-groove P1 'through-groove P2 Cell separation groove P3 Contact groove

Claims (5)

  In a thin film solar cell module in which a plurality of thin film solar cells in which a semiconductor layer and an upper transparent conductive layer are sequentially formed on a metal substrate are connected in series, the metal substrate is separated for each of the thin film solar cells and The thin film solar cell module which connected the upper transparent conductive layer of the thin film photovoltaic cell to the metal substrate of the other thin film photovoltaic cell. 2. A lower conductive layer on a metal substrate, and the upper transparent conductive layer of one thin film solar cell adjacent to each other is connected to the metal substrate of the other thin film solar cell directly or via the lower conductive layer. The thin film solar cell module described.   The thin film solar cell module according to claim 1, wherein the semiconductor layer includes a chalcopyrite structure semiconductor layer. A method of manufacturing a thin film solar cell module in which a plurality of thin film solar cells are connected in series,
Forming a semiconductor layer on a metal substrate in which through grooves are formed in parallel;
Removing the semiconductor layer on one side of the through groove to form a contact groove;
Forming an upper transparent conductive layer on the semiconductor layer and in the contact trench;
Forming a separation groove for separating the upper transparent conductive layer on one side of the through groove from the through groove at a predetermined interval;
A plurality of thin film solar cells separated from each other by the separation groove and connected in series by conduction of the upper transparent conductive layer formed in the contact groove to the metal substrate, including the metal substrate, are translucent. Coating with resin;
The resin sealing body covered with the translucent resin is cut so as to pass through the end portions in the through grooves along the arrangement direction of the through grooves, and the metal substrate is divided into thin film solar cells. A method of manufacturing a thin-film solar cell module including a process.   The manufacturing method of the thin film solar cell module of Claim 4 using the strip | belt-shaped metal substrate which formed the penetration groove | channel at predetermined intervals along the board | substrate longitudinal direction.

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