JP4175724B2 - Method for manufacturing substrate for photovoltaic device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a substrate for a photovoltaic device for extracting output to the back side of the substrate.
[0002]
[Prior art]
Conventionally, a method for manufacturing a substrate for a photovoltaic device for taking out the output to the back side of the substrate is disclosed as a third embodiment of Japanese Patent Laid-Open No. 10-93119 in FIGS. . In this manufacturing method, an opening is provided in the metal substrate using a press working method in order to extract the output to the back side of the metal substrate. Then, an insulating film is disposed so as to fill the protruding burrs generated at the time of pressing, and a conductive film is disposed on the insulating member, and the output is led out from the substrate surface to the back surface. Thus, the insulating film prevents the protruding burrs of the metal substrate from coming into contact with the conductive film and short-circuiting.
[0003]
[Problems to be solved by the invention]
This conventional manufacturing method or structure has the following problems. FIG. 11 is a cross-sectional view of an essential part for explaining this problem. In the figure, reference numeral 21 denotes a metal substrate having an insulating film 22 formed on the entire surface thereof, and there are burrs 23b generated during press working around the opening 23. Reference numerals 24 and 25 denote insulating films arranged by screen printing from the front surface side and the back surface side of the substrate 21, and the insulating films can also be arranged on the side walls in the opening 23. A method for disposing an insulating film on the side wall in the opening 23 by screen printing is described in detail in paragraph 25 of the above publication.
[0004]
In this conventional manufacturing method or structure, the thickness of the insulating film that is actually formed is thin at the end of the opening 23, that is, at the portion of the burr 23b. The tip of the burr 23b comes out from the surface. When the conductive film 26 for extracting output is formed on the insulating film, the conductive film and the metal substrate are short-circuited, and the output cannot be normally extracted.
[0005]
The present invention has been made to solve such problems, and even a metal substrate with burrs can be output to the back side without being short-circuited with the substrate. And it aims at providing the manufacturing method.
[0006]
[Means for Solving the Problems]
The structure of the present invention includes a step of providing a hole or a notch-shaped punched portion in a metal substrate by a pressing method, a step of disposing an insulating member that fills the punched portion, and an insulating member that fills the punched portion. Providing an opening from the front surface side to the back surface side, and disposing a conductive film extending from the front surface side of the substrate through the side wall of the opening to the back surface side of the substrate on the insulating member. It is characterized by.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described in detail with reference to FIGS.
[0008]
In the process shown in FIG. 1, first, an insulating film 2 (film thickness of about 10 to 60 μm) such as silicon oxide or polyimide resin is formed on a metal substrate 1 (thickness 0.1 to 0.5 mm) made of stainless steel or the like in a substantially rectangular shape. ). Next, circular punched portions 3a and 3d (with a diameter of about 0.1 mm) are formed in the vicinity of the lower left and lower right corners of the metal substrate 1 using a pressing method in which the substrate 1 is punched from the front surface side (insulating film 2 side) to the back surface side. 7 to 1.0 mm). Here, as shown in FIGS. 1B and 1C, burrs 3 ab and 3 db protruding about 10 to 30 μm from the back surface of the substrate 1 are formed at the cut portion of the substrate 1. In addition, the circular punched portions 3 a and 3 d are provided here, but a cutout-shaped punched portion provided at the outer peripheral end of the substrate 1 may be used.
[0009]
Next, in the process shown in FIG. 2, substantially rectangular photovoltaic elements A to D each including a metal electrode layer, a semiconductor photoactive layer such as amorphous silicon, and a transparent electrode layer are sequentially formed from the substrate 1 side. . These photovoltaic elements A to D are arranged adjacent to each other along the longitudinal direction of the substrate 1 and are not shown. For example, each of the photovoltaic elements A to D has a structure disclosed in Japanese Patent Publication No. 58-21827. The electromotive force elements A to D are connected in series. In addition, output terminals Aa and Dd extending from the electrode layers of the photovoltaic elements A and D are formed.
[0010]
Next, in the process shown in FIG. 3, insulating members 4 a and 4 d (film thickness of about 30 to 60 μm) are disposed on the outer peripheral portions and inside of the extraction portions 3 a and 3 d from the surface of the substrate 1. This forming method uses the screen printing method from the surface side of the substrate 1 to print the insulating members 4a and 4d such as uncured UV curable resin on the outer peripheral portions of the punched portions 3a and 3d and inside thereof. Then, it hardens | cures by irradiating UV light. At this time, the diameter of the cutout portions 3a and 3d is about 0.7 to 1.0 mm as described above, and is relatively small. By printing and curing an uncured resin, the insulating members 4a and 4d are also arranged and filled in the inside of the extraction portions 3a and 3d.
[0011]
Next, in the process shown in FIG. 4, instead of the back side of the substrate 1, the insulating members 5a, 5d (on the outer peripheral portions of the punched portions 3a, 3d and on the insulating members 4a, 4d in the punched portions 3a, 3d ( A film thickness of about 30 to 60 μm is disposed. This forming method is to cure the insulating members 5a and 5d such as an uncured UV curable resin by irradiating with UV light after printing using a screen printing method. As illustrated, the insulating members 5a and 5d formed on the back surface side of the substrate 1 are substantially rectangular with a large area as compared with the punched portions 3a and 3d.
[0012]
Here, the insulating members 4a and 4d are filled in the extracted portions 3a and 3d, and the insulating members 5a and 5d are disposed on the insulating members 4a and 4d. Therefore, the insulating film is not thinned at the end portions of the extraction portions 3a and 3d, which has a problem in the past, and the tip of the burr does not penetrate the insulating film.
[0013]
Next, in the process shown in FIG. 5, by irradiating the insulating members 4a, 5a, 4d, and 5d positioned at the center of the extraction portions 3a and 3d with a laser beam such as a YAG laser, the openings 6a and 6d ( About 10 to 500 μm in diameter). When the diameter of the opening is about 100 μm or less, a laser beam is irradiated in a spot shape to provide the opening. When the diameter of the opening is about 100 μm or more, the laser light is scanned on the circumference. To provide an opening.
[0014]
Next, in the process shown in FIG. 6, conductive films 7 a and 7 d that fill the openings 6 a and 6 d and reach the output terminals Aa and Dd are formed on the surface of the substrate 1. This forming method uses a screen printing method, and contains powder (particle size: about 3 to 7 μm) such as silver, nickel, aluminum, copper, or carbon in a polyimide or phenol binder, and is patterned by screen printing. Then, it is heat-cured at 150 ° C. to form a thickness of about 10 to 50 μm.
[0015]
In the step shown in FIG. 7, instead, on the back side of the substrate 1, conductive films 8 a and 8 d are formed on the insulating members 5 a and 5 d and on the conductive films 7 a and 7 d in the openings 6 a and 6 d. As a result, the output terminals Aa and Dd and the conductive films 8a and 8d are brought into conduction, and the photovoltaic device is completed. The formation method and material of the conductive films 8a and 8d are the same as those of the conductive films 7a and 7d. And since the shape of these electrically conductive films 8a and 8d is a substantially rectangular shape with a large area, a separately prepared lead member (not shown) can be easily connected. Here, in the conductive films 8a and 8d, in the case where a metal material is used for the powder with priority on conductivity, the conductive film is used to prevent the metal powder from being exposed to the outside air and corroding its surface on the back surface of the substrate 1. A carbon paste containing carbon powder resistant to corrosion may be formed on 8a and 8d (not shown). Moreover, since the shape of the conductive films 8a and 8d is the back side of the substrate 1, any shape can be adopted.
[0016]
Here, the insulating members 4a and 4d are filled in the extracted portions 3a and 3d, and the insulating members 5a and 5d are disposed on the insulating members 4a and 4d. Therefore, the insulating film is not thinned at the end portions of the extraction portions 3a and 3d, which has a problem in the past, and the tip of the burr does not penetrate the insulating film. Therefore, even if openings 6a and 6d are provided in the insulating film and a conductive film is disposed from the front surface side of the substrate 1 through the side walls of the openings 6a and 6d to the back surface side, the conductive film is electrically connected to the substrate. The output can be taken out normally.
[0017]
Next, the short-circuit state between the output terminal and the substrate was investigated using the photovoltaic device of this example and the conventional photovoltaic device disclosed in FIG. As a result, in the present example, no short circuit occurred at all, whereas in the conventional product, a 78% short circuit occurred. Thereby, in the present Example, it has confirmed that the short circuit with an output terminal and a board | substrate could be prevented reliably.
[0018]
Next, a second embodiment of the present invention will be described in detail with reference to FIGS. In the process shown in FIG. 8, first, the lower left of the metal substrate 1 is formed using a pressing method in which the metal substrate 11 (thickness 0.1 to 0.5 mm), such as stainless steel, is punched from the front surface side to the back surface side. In the vicinity of the lower right corner, circular punched portions 13a and 13d (diameter of about 0.7 to 1.0 mm) are provided. Here, as shown in FIGS. 8B and 8C, burrs 13 ab and 13 db protruding about 10 to 30 μm from the back surface of the substrate 11 are formed at the cut portion of the substrate 11. In addition, although the circular punched portions 13 a and 13 d are provided here, a cutout-shaped punched portion provided at the outer peripheral end of the substrate 11 may be used.
[0019]
Next, in the process shown in FIG. 9, an insulating film 12S (film thickness of about 30 to 60 μm) as an insulating member on the surface of the substrate 11 and an insulating film 12R (film thickness of about 30 to 60 μm) as an insulating member on the back surface of the substrate 11 are used. ). These insulating films are formed by uniformly applying a varnish, which is a base material of a polyimide film, with a spin coater or a roll coater, etc., and processing while raising the temperature stepwise from 100 to 300 ° C. . Further, when coating the varnish, the varnish also enters inside the extracted portions 13a and 13b of the substrate 11, and after the heat treatment, as shown in FIG. 9, the inside of the extracted portions 13a and 13b is filled with an insulating film, Be placed. Therefore, the insulating film is not thinned at the end portions of the extraction portions 13a and 13d, which has a problem in the past, and the tip of the burr does not penetrate the insulating film.
[0020]
Next, the insulating members 4a, 4d, 5a, and 5d in the first embodiment are not disposed, and the same steps as those in FIGS. 2 and 5 to 7 in the first embodiment are used. As shown in FIG. The photovoltaic device in the embodiment is completed. Hereinafter, the same manufacturing method and structure as those of the first embodiment will be described using the same names and symbols.
[0021]
In the second embodiment, similarly to the first embodiment, the insulating portions 12A and 12R are filled in the extracted portions 13a and 13d. Therefore, the insulating film is not thinned at the end portions of the extraction portions 13a and 13d, which has a problem in the past, and the tip of the burr does not penetrate the insulating film. Therefore, even if the openings 6a and 6d are provided in the insulating film and a conductive film is provided from the front surface side of the substrate 11 to the back surface side through the side walls of the openings 6a and 6d, the conductive film is electrically connected to the substrate. The output can be taken out normally.
[0022]
【The invention's effect】
The present invention provides a step of providing a hole or a notch-shaped punched portion in a metal substrate by a pressing method, a step of disposing an insulating member that fills the punched portion, and an insulating member that fills the punched portion, from the front side to the back side of the substrate. The insulating member is not thinned at the end of the punched portion, and therefore, burrs generated during pressing at the end of the punched portion do not penetrate the insulating member. . Therefore, even if a conductive film extending from the front surface side of the substrate to the back surface side through the side wall of the opening is disposed in the subsequent process, the conductive film does not conduct to the substrate.
[Brief description of the drawings]
1A and 1B show a first step of a first embodiment of the present invention, in which FIG. 1A is a plan view, FIG. 1B is an AA enlarged sectional view in FIG. 1A, and FIG. It is.
FIGS. 2A and 2B show a second step of the first embodiment of the present invention, where FIG. 2A is a plan view, FIG. 2B is an AA enlarged sectional view in FIG. It is.
FIGS. 3A and 3B show a third step of the first embodiment of the present invention, where FIG. 3A is a plan view, FIG. 3B is an enlarged cross-sectional view along A-A in FIG. It is.
FIGS. 4A and 4B show a fourth step of the first embodiment of the present invention, where FIG. 4A is a plan view, FIG. 4B is an AA enlarged sectional view in FIG. (D) is a bottom view.
FIGS. 5A and 5B show a fifth step of the first embodiment of the present invention, where FIG. 5A is a plan view, FIG. 5B is an AA enlarged sectional view in FIG. (D) is a bottom view.
6A and 6B show a sixth step of the first embodiment of the present invention, in which FIG. 6A is a plan view, FIG. 6B is an enlarged cross-sectional view taken along line AA in FIG. It is.
FIGS. 7A and 7B show a seventh step of the first embodiment of the present invention, wherein FIG. 7A is a plan view, FIG. 7B is an AA enlarged sectional view in FIG. (D) is a bottom view.
FIGS. 8A and 8B show a first step of the second embodiment of the present invention, where FIG. 8A is a plan view, FIG. 8B is an AA enlarged sectional view in FIG. It is.
9A and 9B show a second step of the second embodiment of the present invention, in which FIG. 9A is a plan view, FIG. 9B is an AA enlarged sectional view in FIG. 9A, and FIG. It is.
FIG. 10 shows a completed view of the second embodiment of the present invention, (a) is a plan view, (b) is an AA enlarged sectional view in (a), (c) is an BB enlarged sectional view, (D) is a bottom view.
FIG. 11 is a cross-sectional view of a principal part showing a conventional photovoltaic device substrate.
[Explanation of symbols]
1, 11 Metal substrates 3a, 3d, 13a, 13d Cutouts 4a, 4d, 5a, 5d Insulating members 6a, 6d Openings 7a, 7d, 8a, 8d

Claims (1)

Providing a metal substrate with a punched portion having a burr on the back side of the metal substrate by a pressing method;
An insulating member that fills a punched portion having a burr on the back side of the metal substrate from the metal substrate front side, and then fills a punched portion having a burr on the back side of the metal substrate from the back side of the metal substrate. A step of arranging
A step of providing an opening from the front surface side of the substrate to the back surface side in an insulating member that fills a punched portion having burrs on the back surface side of the metal substrate;
Disposing a conductive film from the front surface side of the substrate through the side wall of the opening to the back surface side of the substrate on the insulating member;
A method for producing a substrate for a photovoltaic device, comprising:

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