JP2009076715A - Manufacturing method of thin film solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a thin film solar cell which can be stably mass-produced while a groove is prevented from being formed circumferentially outside a die-side substrate cutting hole during connection to a substrate or formation of a current collection hole, and trouble such as slug float, drooping of a film surface, burrs of a reverse surface side, etc., is prevented. <P>SOLUTION: The present invention relates to the manufacturing method of the thin film solar cell wherein the substrate 61 is disposed on a die D of a metal mold, a stripper plate Ps is disposed on a top surface of the substrate 61, and a hole is bored in the substrate 61 through the stripper plate Ps with a punch P, a die sheet Ds being sandwiched between the Die D and substrate 61 and bored after the substrate 61 is bored. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a thin-film solar cell that generates electric power using sunlight by being installed on a roof of a house, a roof of a building, etc., and a substrate is disposed on a die of a mold, and the substrate It is related with the manufacturing method of the thin film solar cell which arrange | positions a stripper plate on the upper surface of this and performs a punching process to the said board | substrate through the said stripper plate by punching.

Currently, clean energy research and development is underway from the standpoint of environmental protection. Among them, solar cells that generate electricity using sunlight by laying outdoors on the roof of a house, building rooftop, etc., have unlimited resources (sunlight), no pollution Therefore, it attracts attention.
A typical example of a solar cell (photoelectric conversion device) in which a plurality of photoelectric conversion elements formed on the same substrate are connected in series is a thin film solar cell. This thin-film solar cell is considered to become the mainstream of future solar cells because it is thin and lightweight, inexpensive to manufacture, and easy to increase in area. Demand is also expanding for business use and general residential use.

Conventional thin-film solar cells generally used a glass substrate, but the glass substrate is thick and heavy, and has the disadvantage of being easily broken, so in recent years, in terms of weight reduction, workability, mass productivity, etc. Research and development of flexible solar cells using plastic films are being promoted and put into practical use. And this flexible property was utilized, and mass production became possible by manufacturing methods, such as a roll-to-roll system and a stepping roll system.
When forming a thin film solar cell on a flexible insulating substrate such as the plastic film, by placing an electrode on the opposite surface side (back surface side) of the solar cell of the substrate, and connecting through the substrate, The ratio of the solar cell area to the substrate area can be increased.

  FIG. 4 is a schematic view of a roll-to-roll substrate hole forming apparatus. In FIG. 4, the substrate 61 sent out from the unwinding roll R1 is sequentially transferred to a predetermined position at a predetermined position by a position detection hole P1, a connection hole hole P2, and a current collecting hole hole P3. After a number of position detection holes, connection holes, and current collecting holes are opened, the film is wound around the winding roll R2. In this case, the conveying method and the conveying distance are arbitrarily controlled corresponding to the positions of these holes.

FIG. 5 is a schematic diagram showing an example of the prior art of the method for manufacturing the thin-film solar cell substrate shown in FIG. 4, (A) shows the state before drilling, and (B) shows the state after drilling. Is shown.
In FIG. 5, the opening has a punch P having the same cross section as the hole in the substrate 61, a stripper plate Ps having an opening having the same cross section as the punch P, and a die having an opening having the same cross section. D.
These dies D and punches P are arranged to form an arbitrary clearance C. Further, the substrate 61 that has been transported and stopped onto the die D and the stripper plate Ps is pressed by the stripper plate Ps, and then the punch P punches out (penetrates) the substrate 61, and a hole is made in the substrate 61. Note that the symbol S is a punched residue.

  On the other hand, Patent Document 1 (Japanese Patent Application Laid-Open No. 10-190024) discloses a punch whose cross section is the same shape as the hole of the substrate, and a stripper plate having an opening portion having the same cross sectional shape as the punch. Consists of dies having apertures with the same cross-sectional shape, and a plurality of substrates or a substrate and an auxiliary film are sandwiched between a die or a stripper plate having a hardness higher than that of the substrate, and the substrate and the auxiliary film are stripped. After being pressed by the plate, the punch punches out (penetrates) the substrate, and a hole is made in the substrate.

Japanese Patent Laid-Open No. 10-190024

The method for drilling a substrate for a thin film solar cell according to the prior art described in FIG. 5 and Patent Document 1 has the following problems. In addition, the code | symbol has shown the code | symbol of FIG.
(1) The inner wall surface and upper surface of the hole of the die D and the side surface and the bottom surface of the punch P are formed in a sharp blade shape so that the crests formed by the respective surfaces can be easily connected and disconnected. Therefore, the substrate (workpiece) 61 (1a) is cut simultaneously from both sides at the time of cutting, but since the cutting hole diameter is determined by the diameter of the punch P, the cutting of the die D does not lead to cutting, and the substrate cutting on the die D side is performed. A circumferential groove is formed outside the hole.
Due to this groove, the transparent electrode layer and the fourth electrode layer do not cover the groove, and a cut is generated, and the connection between the first electrode layer and the third electrode layer or the transparent electrode layer and the fourth electrode layer through the hole is made. The resistance is remarkably increased, and as a result, the fill factor of the solar cell is lowered and the conversion efficiency of the solar cell is sometimes lowered.

  (2) Since the substrate (workpiece) 61 (1a) is drawn to the die D side by the clearance C at the time of cutting, and the substrate 61 (1a) is a soft material, the substrate 61 (1a) extends when being drawn. As a result, the film surface on the processing surface side is “sagging” and large burrs are generated on the back surface side. In the case of forming current collecting holes, a cylindrical crack is generated in the first electrode layer formed on the substrate 61 (1a). Therefore, the first electrode layer and the transparent electrode layer are in contact without the photoelectric conversion layer covering the cracks generated in the first electrode layer, resulting in a decrease in the solar cell fill factor and the conversion efficiency of the solar cell. Will fall.

  (3) When the punch is pulled up when the connection hole or the current collecting hole is formed, the inside of the die D is in a vacuum state, the punched residue remains stuck to the tip of the punch P, and the residue rises onto the die D Will occur. As a result, the substrate 61 (1a) and the die D are often pressed between the substrate 61 (1a) and the die D when the next connection hole or current collecting hole is formed. When the current collecting holes are formed, the electrode film may be cracked or peeled off.

  In order to reduce the above-described dregs rise, sagging on the front side and burrs on the back side, the clearance P between the punch P and the die D can be reduced as much as possible. When the clearance C between the die D and the die D is reduced as much as possible, there is a problem that not only the manufacturing cost of the mold increases, but it is difficult to reduce the clearance C to the limit in terms of manufacturing technology.

  The present invention has been made in view of such circumstances, and its purpose is to form a circumferential groove on the outside of a die-side substrate cutting hole when forming a connection hole or a current collecting hole in the substrate. Another object of the present invention is to provide a method of manufacturing a thin-film solar cell that can be stably mass-produced by preventing occurrence of defects such as dregs, sagging of the film surface and burrs on the back surface side.

  In order to solve the above-described problems of the prior art, the present invention provides a substrate disposed on a die of a mold, a stripper plate is disposed on the upper surface of the substrate, and the substrate is punched through the stripper plate. A method of manufacturing a thin-film solar cell, in which a die sheet is sandwiched between the die and the substrate, and the die sheet is perforated after the substrate is perforated.

  The present invention specifically relates to a method for drilling current collecting holes and connection holes of an insulating substrate, and the first electrode layer is formed on the surface of the insulating substrate manufactured on a roll. A photoelectric conversion layer made of a thin film semiconductor layer, a photoelectric conversion element in which a transparent electrode layer (second electrode layer) is sequentially laminated, and a connection electrode layer made of a third electrode layer and a fourth electrode layer on the back surface of the substrate. The photoelectric conversion element and the connection electrode layer are each separated into a plurality of unit parts, and are formed by shifting the separation positions of the photoelectric conversion element and the connection electrode layer through current collecting holes formed in the formation region of the transparent electrode layer. The transparent electrode layer of the photoelectric conversion element that is adjacent to the connection electrode layer through the connection hole for series connection formed outside the transparent electrode layer area of the photoelectric conversion element in the area of the connection electrode layer. The first extending outside the region of A thin-film solar cell that reaches the extreme layer and directly sustains both photoelectric conversion elements, the die having a means for holding the current collector hole or the connection hole by a die and a punch and holding the substrate In a method of manufacturing a thin film solar cell in which a plurality of thin film solar cells are formed at predetermined positions by punching using a die, a die sheet is sandwiched between the die of the mold and the substrate, and the die sheet is punched after the substrate is punched. .

The present invention is preferably configured as follows.
(1) The die sheet is processed with a punch after punching the substrate, so that the opening of the die sheet has the same dimensions as the punch.
(2) The die sheet is made narrower than the die width of the mold, and a step is provided by shortening the winding side of the substrate as viewed from the opening position.
(3) The die sheet is formed to have a length on the winding side of the substrate of 1 mm or less when viewed from the opening position.
(4) A step is formed on the side of the substrate with the thickness of the die sheet being twice the thickness of the substrate to be processed.
(5) The die sheet is formed of a resin material having an elastic modulus of 6.5 GPa or more.

As described above, the method for manufacturing a thin-film solar cell according to the present invention includes forming a plurality of holes such as current collecting holes and connection holes at predetermined positions by punching a substrate using a die of a mold. Since the die sheet is sandwiched between the die of the mold and the substrate, and the die sheet is perforated after the substrate is perforated, the substrate and the die sheet laid on the die are punched at the same time. The inner diameter is in contact with the upper part of the die sheet, the deformation of the substrate is handled by the die sheet, the deformation of the lower part of the substrate can be prevented, and high-precision hole processing can be performed. Therefore, when punching out the substrate with a punch, it is possible to reliably prevent circumferential grooves from being formed on the die side surface of the hole in the substrate.
Therefore, by preventing the formation of the groove, it is possible to suppress an increase in connection resistance between the first electrode layer and the third electrode layer or the transparent electrode layer and the fourth electrode layer through the hole, and as a result, the curve of the solar cell It is possible to prevent a decrease in factor and a decrease in conversion efficiency of the solar cell.
Further, the radial clearance of the die sheet is not formed, and the elongation of the substrate can be suppressed by the die sheet, so that the sagging on the processed surface side of the substrate and the generation of burrs on the back surface side can be prevented.

  In addition, the die sheet is made narrower than the width of the die and the winding side of the substrate is shortened when viewed from the opening position to provide a step, and more specifically, the substrate winding is viewed when viewed from the opening position. The side length is set to 1 mm or less, and the die sheet thickness is twice the thickness of the substrate to be processed to form a step on the side of the substrate, thereby sticking to the tip of the punch. By dropping the punched waste as it is on the step between the die sheet and the die provided on the winding side, it is not necessary to press the punch with a punch between the die and the substrate. ) Over the stepped portion with the die sheet, it is possible to avoid the occurrence of damage to the electrode film due to the dent.

  Furthermore, a high-quality thin film solar cell can be manufactured by forming the die sheet from a resin material that is at least larger than the elastic modulus of the substrate, specifically, an elastic modulus of 6.5 GPa or more.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a perspective view showing a schematic configuration of a thin film solar cell to which the present invention is applied.
In the thin film solar cell, a first electrode layer 62, a photoelectric conversion layer 63 made of a thin film semiconductor layer, and a transparent electrode layer (also referred to as a second electrode layer) 64 are sequentially laminated on the surface of a flexible insulating substrate 61. A conversion element is formed. A connection electrode layer 65 including a third electrode layer and a fourth electrode layer is formed on the back surface of the substrate 61.
The photoelectric conversion element and the connection electrode layer 65 are completely separated into a plurality of unit units, and are formed by shifting the separation positions. For this reason, the current generated in the photoelectric conversion layer 63 of the unit photoelectric conversion element (also referred to as a unit cell) is first collected in the transparent electrode layer 64, and then the current collection hole 67 formed in the region of the transparent electrode layer 64. The connection electrode layer 65 on the back surface is communicated with each other.

Furthermore, it extends outside the transparent electrode layer region of the adjacent photoelectric conversion element through the connection hole 68 for series connection formed outside the transparent electrode layer region of the photoelectric conversion element in the region of the connection electrode layer 65. The first electrode layer 62 is reached, and both photoelectric conversion elements are connected in series.
In this way, by repeating the series connection of the separated unit photoelectric conversion elements in series, the first electrode layer 62 of the first photoelectric conversion element and the transparent electrode layer 64 of the last photoelectric conversion element are formed. It becomes possible to output a necessary voltage.
For example, in order to obtain an alternating current of 100 V as a commercial power source by making an alternating current with an inverter, 100 V or higher is desirable.

  The substrate 61 is a polyimide film having a thickness of about 50 μm. In addition, polyethylene naphthalate (PEN), polyethersulfone (PES), polyethylene terephthalate (PET), aramid film, etc. Can be used.

Next, a method for assembling and manufacturing the thin film solar cell having such a configuration will be described.
First, a plurality of connection holes 68 are formed in a predetermined position of the substrate 61 by punching with a die and a punch die. Next, a first electrode layer 62 is formed on the surface of the substrate 61 and a third electrode layer (not shown) is sequentially formed on the back surface (the first electrode layer 62 and the third electrode layer may be formed in reverse order). At this time, the first electrode layer 62 and the third electrode layer overlap with each other on the inner surface of the connection hole 68 and are electrically connected to each other.
As these electrode layers, a metal such as Ag, Al, Cu, or Ti may be formed by sputtering or electron beam evaporation, or a metal oxide film and a metal multilayer film may be used as the electrode layers.

  Next, similarly to the connection hole 68, a plurality of current collecting holes 67 are formed at predetermined positions on the substrate 61 by punching with a die and a punch die. Then, a primary patterning line for linearly removing the first electrode layer 62 formed on the surface of the substrate 61 is formed, and a primary patterning area in which a plurality of individual single regions (electrodes) are formed is formed. A photoelectric conversion layer 63 and a transparent electrode layer 64 made of a semiconductor layer are sequentially formed thereon.

  Next, a fourth electrode layer made of a low-resistance conductive film such as a metal film (not shown) is formed on the third electrode layer (not shown) on the back side to form a connection electrode layer 65. At this time, the transparent electrode layer 64 and the connection electrode layer 65 overlap with each other on the inner surface of the current collecting hole 67 and can be electrically connected to each other. The photoelectric conversion layer 63 is a thin film semiconductor layer, and a-Si (amorphous silicon) is a typical example. The transparent electrode layer 64 generally uses an oxide conductive layer such as ITO (indium tin oxide), SnO2, or ZnO. When the film is formed, the periphery of the connection hole 68 is covered with a mask or the like so that the film is not formed on the portion of the connection hole 68 formed first.

Next, a secondary patterning line in which the transparent electrode layer 64 and the photoelectric conversion layer 63 are removed in a straight line is processed so as to overlap the primary patterning line in the primary patterning area. Here, the photoelectric conversion element including the first electrode layer 62, the photoelectric conversion layer 63, and the transparent electrode layer 64 is separated into a plurality of unit units.
Finally, a patterning line is processed in a straight line in the connection electrode layer 65 composed of the third electrode layer and the fourth electrode layer at a position shifted from the unit photoelectric conversion element. Here, the connection electrode layer 65 is separated into a plurality of unit units, and the series connection of the thin film solar cells is completed. The patterning is often performed mainly by laser processing, but may be performed by a sandblasting method or a mechanical cutter.

  The present invention relates to a method for processing holes processed in the substrate 61, such as the connection holes 68 and the current collecting holes 67 of the thin-film solar cell configured as described above.

FIG. 1 shows a method of drilling a substrate for a thin film solar cell according to an embodiment of the present invention, (A) shows a state before drilling, and (B) shows a state after drilling.
In FIG. 1, the opening has a punch P having the same shape as the hole of the substrate 61, a stripper plate Ps having an opening having the same cross-sectional shape as the punch P, and a gold having an opening having the same cross-sectional shape. It consists of a die D of the mold.
Then, the die sheet Ds is sandwiched between the die D and the substrate 61, and the stripper plate Ps is placed on the upper side of the substrate 61. An arbitrary clearance C is formed between the outer diameter of the punch P and the inner diameter of the die D. Moreover, as shown to FIG. 1 (A), the die sheet | seat Ds is not opened at the time of laying.
Furthermore, the die sheet Ds has a shape in which the winding side (L1), which is the conveyance direction of the substrate 61 (the direction of the arrow Z in FIG. 1A), is shorter than the inlet side (L2) when viewed from the opening position. ing. The length of the winding side (L1) is preferably about 1 mm.

  In such a state of the opening portion, the opening of the substrate 61 or the substrate 61 on which the first electrode layer and the third electrode layer are formed is sent out using the hole forming apparatus shown in FIG. As shown in FIG. 1 (A), the substrate 61 is disposed by being transferred to the upper part of the die D on which the die sheet Ds is laid, that is, the upper part of the die sheet Ds, and then stops.

  In this stopped state, as shown in FIG. 1B, after the substrate 61 is pressed by the stripper plate Ps, the punch P is dropped downward, and the substrate 61 and the die sheet Ds are simultaneously punched by the punch P. Thus, in the first opening, the die sheet Ds is punched with a diameter of D1 together with the substrate 61. Next, in the second and subsequent openings, the die sheet Ds is pulled out and only the substrate 61 is punched out. This operation is repeated a predetermined number of times to open holes at predetermined positions on the substrate 61. Note that the symbol S is a punched residue.

Accordingly, by simultaneously punching the substrate 61 and the die sheet Ds laid on the die D with the punch P, the lower inner diameter of the substrate 61 is in contact with the upper portion of the die sheet Ds. Deformation in the lower part can be prevented. Therefore, when the substrate 61 is punched with the punch P, it is possible to prevent a circumferential groove from being formed on the surface of the hole of the substrate 61 on the die D side.
Moreover, by preventing the formation of such grooves, it is possible to suppress an increase in connection resistance between the first electrode layer and the third electrode layer or the transparent electrode layer and the fourth electrode layer through the hole, and as a result, the curve of the solar cell It is possible to prevent a decrease in factor and a decrease in conversion efficiency of the solar cell.

  Further, since the radial clearance C of the die sheet Ds is not formed and the extension of the substrate 61 can be suppressed by the die sheet Ds, occurrence of sagging on the processed surface side of the substrate 61 and generation of burrs on the back surface side can be prevented. .

FIG. 2 is a schematic diagram showing a state when the punch is pulled out from the die sheet, showing the effect of the die sheet in the method for punching the substrate for a thin film solar cell according to the embodiment of the present invention.
As shown in FIG. 2, the die sheet Ds is made narrower than the width of the die D so that the winding side (L1) of the substrate 61 is shortened when viewed from the opening position, and a step portion T is provided. Is formed so that the length (L1) on the winding side of the substrate 61 as viewed from the opening position is 1 mm or less, and the thickness of the die sheet Ds is twice the thickness of the substrate 61 to be processed. By forming the stepped portion T in the part, the scrap S left adhered to the tip of the punch P falls to the stepped portion T between the die sheet Ds and the die D provided on the winding side (L1). Let At this time, a recovery duct (not shown) may be provided in the vicinity of the mold in order to remove the punched residue S that has fallen on the stepped portion T, for example, by ion blow and guide it downstream.
Therefore, pressing does not occur with the punch S between the die D and the substrate 61, and the falling scrap (the scrap S) does not exceed the stepped portion T with the die sheet Ds. The occurrence of damage due to dents can be avoided.

  The die sheet Ds is preferably formed of a resin material that is at least larger than the elastic modulus of the substrate 61, specifically, an elastic modulus of 6.5 GPa or more.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various changes and modifications can be made based on the technical idea of the present invention.

It is a schematic diagram which shows the drilling method of the board | substrate for thin film solar cells which concerns on embodiment of this invention, (A) shows the state before drilling, (B) has shown the state after drilling. In the drilling method of the board | substrate for thin film solar cells which concerns on embodiment of this invention, it is a schematic diagram which shows the effect of a die sheet, and has shown the state when pulling out a punch from a die sheet. (A), (B), (C) is a perspective view which shows schematic structure of the thin film solar cell with which this invention is applied. It is a schematic diagram which shows the hole formation apparatus of the board | substrate of a roll-to-roll system. It is a schematic diagram which shows an example of the prior art of the manufacturing method of the board | substrate for thin film solar cells shown by FIG. 4, (A) shows the state before drilling, (B) has shown the state after drilling. .

Explanation of symbols

P Punch Ds Die sheet Ps Stripper plate D Die S Dregs 61 Substrate 62 First electrode layer 63 Photoelectric conversion layer 64 Transparent electrode layer (second electrode layer)
65 Connection electrode layer 67 Current collection hole 68 Connection hole

Claims (7)

  A method of manufacturing a thin film solar cell, in which a substrate is disposed on a die of a mold, a stripper plate is disposed on an upper surface of the substrate, and punching is performed through the stripper plate by punching, A method for manufacturing a thin-film solar cell, comprising: sandwiching a die sheet between the die and the substrate; and punching the die sheet after the substrate is punched.   A photoelectric conversion element in which a first electrode layer, a photoelectric conversion layer made of a thin film semiconductor layer, and a transparent electrode layer are sequentially laminated on the surface of an insulating substrate manufactured on a roll; and a third electrode on the back surface of the substrate. A connection electrode layer comprising an electrode layer and a fourth electrode layer, wherein the photoelectric conversion element and the connection electrode layer are each separated into a plurality of unit parts and formed by shifting the separation positions, and the transparent electrode A connection for series connection formed through the current collecting holes formed in the layer formation region and connected to the connection electrode layer, and further formed outside the transparent electrode layer region of the photoelectric conversion element in the connection electrode layer region. A thin-film solar cell that reaches the first electrode layer extending outside the transparent electrode layer region of the adjacent photoelectric conversion element through a hole and directly sustains both photoelectric conversion elements, the current collector The hole or the connecting hole In a method for manufacturing a thin-film solar cell, wherein a plurality of sheets are formed at predetermined positions by punching using a mold comprising a punch and having means for holding the substrate, a die sheet between the die of the mold and the substrate The die sheet is perforated after the substrate is perforated, and the method for producing a thin-film solar cell is provided.   3. The method for manufacturing a thin-film solar cell according to claim 1, wherein the die sheet is processed with a punch after the substrate is punched, so that the opening of the die sheet has the same size as the punch.   3. The thin film according to claim 1, wherein the die sheet is narrower than a die width of the mold, and a step is provided by shortening a winding side of the substrate as viewed from the opening position. A method for manufacturing a solar cell.   The method for producing a thin-film solar cell according to claim 4, wherein the die sheet is formed to have a length on the winding side of the substrate of 1 mm or less when viewed from the opening position.   5. The method of manufacturing a thin-film solar cell according to claim 4, wherein the thickness of the die sheet is twice the thickness of the substrate to be processed, and a step is formed on a side portion of the substrate.   The method for producing a thin-film solar cell according to claim 1 or 2, wherein the die sheet is formed of a resin material having an elastic modulus of 6.5 GPa or more.

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