JPH07321353A - Photovoltaic element and manufacture - Google Patents

Abstract

PURPOSE:To provide a low cost and reliable photovoltaic element by changing applying and hardening steps of conductive adhesive. CONSTITUTION:With a photovoltaic element 101, that comprises a semiconductor layer for photoelectric conversion and an electrode 103 that collects generated power from a semiconductor layer, an electrode is formed by fixing with compression bonding, thermocompresson bonding or thermal bonding of a fine metal wire that is applied and dried with at least one kind of a first conductive adhesive beforehand on the surface of a light receiving part of the photovoltaic element. A terminal member 104 to transmit power collected by the electrode 103 to the outside of the element is arranged on the surface of the photovoltaic element, the electrode is fixed with a surface of a light receiving part and a surface of the terminal member, and on a part of the terminal member with which an electrode is fixed, a second conductive adhesive is applied beforehand.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to photovoltaic devices.
In particular, the present invention relates to a method for connecting an electrode and a terminal member for extracting electric power in a photovoltaic element having a semiconductor layer for photoelectric conversion.

[0002]

2. Description of the Related Art Thermal power generation, which has been a main source of electric power in the past, is problematic from the viewpoint of preventing global warming, and in recent years, an energy source with a smaller amount of CO ₂ emission has been demanded. On the other hand, it has been pointed out that nuclear power generation that does not emit CO ₂ may cause serious environmental pollution due to radioactive substances. From this aspect, urgent development of a pollution-free and safe energy source is being demanded.

Among the clean energy sources that are expected in the future, solar cells composed of photovoltaic elements have attracted a great deal of attention because of their pollution-free property, safety, and ease of handling.

At present, photovoltaic devices are not popular because it is difficult to obtain user merits commensurate with investment in purchasing photovoltaic devices. Specifically, it is due to the following two reasons.

(A) The manufacturing cost of the photovoltaic element cannot be reduced easily and the purchase price is high. (B) Since the reliability of the photovoltaic element is not yet sufficient,
There may be cases where the purchase investment cannot be fully returned due to long-term use.

First, the situation will be described below from the viewpoint that the manufacturing cost of (a) above is high. Generally, even amorphous silicon photovoltaic devices, which are said to have relatively low manufacturing costs, have not yet reached the price of widespread use. At present, the following approaches are taken from the viewpoint of reducing the manufacturing cost of photovoltaic elements.

(1) Reduction of manufacturing cost of semiconductor layers. For example, the use of amorphous silicon reduces the amount of materials used and enables large-area film formation at high speed. (2) The price per unit amount of power generation is reduced by improving the power generation efficiency of the semiconductor layer. (3) Cost reduction of the commercialization process. For example, lowering the price of materials used, reducing the amount used, and simplifying the assembly process. (4) Reduction of the price per unit of power generation by reducing the loss associated with the commercialization process.

Further, from the viewpoint of ensuring the above-mentioned (b) long-term reliability, the following approach is taken.

(5) Use of a highly moisture-proof coating material (eg, glass) to suppress entry of harmful humidity into the photovoltaic element. (6) The connection portion of the electrode member and the terminal member is formed by a method having high reliability.

The object of the present invention is (3) out of the above 6 items.
And (6) are to be improved. In particular, in order to reduce the cost of the commercialization process, it is important to reduce the number of manufacturing devices by developing a technology that allows the process itself to be omitted.

Further, by simplifying the connecting portion of the electrode member and the terminal member, not only the cost can be reduced but also the reliability of the connecting portion can be improved, and a long life corresponding to the initial investment can be obtained. Things are also important.

FIG. 4 is a schematic view showing a conventional photovoltaic element, which is the photovoltaic element viewed from the front (light receiving surface) side. The photovoltaic element of FIG. 4 is composed of a conductive substrate that supports the entire photovoltaic element, an amorphous semiconductor layer, an electrode layer, a collecting electrode, and a lead terminal that are sequentially formed on the surface of the substrate. Has been done. The conductive substrate is made of a metal material such as stainless steel, and the semiconductor layer is composed of a back surface reflection layer, a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer in order from the bottom layer. Here, p-type semiconductor layer, i-type semiconductor layer, n
Type semiconductor layer is formed by CVD (Chemical Vaper Deposition)
The films are laminated by a film forming method such as a method so that light can be efficiently taken in and efficiently converted into electric power. Further, as the above-mentioned electrode layer, a transparent conductive film of indium oxide or the like is formed to serve as both antireflection means and current collecting means.

The transparent conductive film is made of FeCl ₃ , AlCl ₃
It is formed by applying an etching paste containing the above by a method such as screen printing and then heating. Further, the etching line 401 is a portion where the transparent conductive film is linearly removed. The purpose of partially removing the transparent conductive film is to prevent the influence of the short circuit between the substrate and the transparent conductive film from affecting the effective light receiving range of the photovoltaic element. For example, such a short circuit may occur when the outer circumference of the photovoltaic element is cut off.

A collector electrode 402 for efficiently collecting the generated electric power is formed on the surface of the photovoltaic element. The collector electrode 402 uses a thin metal wire having a low resistance such as copper as a core material, and a conductive adhesive for adhesion is applied to the outer periphery of the thin metal wire and dried, and then cut into a predetermined length, After being aligned, they are fixed to the surface of the effective light receiving area by thermocompression bonding.

The electric power collected by the above-mentioned current collecting electrode 402 is transferred to the takeout terminals 403 provided on both sides for taking out to the outside. The take-out terminal 403 is a foil body made of a low resistance metal such as copper, and the insulating member 404 is provided in the lowermost layer.
It is insulated from the surface of the photovoltaic element.

On the other hand, the connecting portion between the current collecting electrode 402 and the takeout terminal 403 is coated in a spot shape with a conductive adhesive 405 to ensure the reliability of bonding.

[0017]

The above-mentioned conventional method has the following problems.

(1) A process for applying the conductive adhesive in spots, a heat treatment process for curing the conductive adhesive, and the like are required, and the processing time is long because the number of operations is large. Further, the manufacturing apparatus for realizing these steps is complicated.

(2) The material cost of the conductive adhesive is high and the manufacturing cost is high.

(3) Since the conductive adhesive applied in spots has a convex shape, it is necessary to increase the thickness of the surface coating material. Therefore, the material cost is also increased.

(4) The surface of the terminal member made of a material such as copper is deteriorated by oxidation due to the thermal process in the manufacturing process which the photovoltaic element receives before the application of the conductive adhesive, It is difficult to obtain a sufficiently low connection resistance even by applying a conductive adhesive. Further, the reliability is low for the same reason.

[0022]

The photovoltaic element of the present invention is a photovoltaic element having a semiconductor layer for photoelectric conversion and an electrode for collecting the electric power generated in the semiconductor layer. The electrode is one in which at least one kind of first conductive adhesive is applied and dried in advance and fixed to the surface of the light receiving surface of the photovoltaic element by pressure bonding, thermocompression bonding or heating. A terminal member for transmitting the electric power collected by the electrode to the outside of the photovoltaic element is provided on the surface of the photovoltaic element, and the electrode is fixed on the surface of the light receiving surface of the photovoltaic element. And also fixed on the surface of the terminal member, and at least a portion of the terminal member to which the electrode is fixed has a second
It is characterized in that the conductive adhesive is applied in advance.

[0023]

In the present invention, the electrode is obtained by fixing at least one kind of the first conductive adhesive and drying the fine metal wire on the surface of the light receiving surface of the photovoltaic by pressure bonding, thermocompression bonding or heating. Since the second conductive adhesive is applied in advance to at least the portion of the terminal member where the electrodes are fixed, the following four items can be realized.

(1) The step of applying a conductive adhesive after forming the above-mentioned electrodes, which is conventionally required, can be omitted. As a result, it is possible to significantly reduce the cost of the manufacturing process.
Needless to say, the step of applying the conductive adhesive on the terminal member is necessary (off-line), but since the step can be collectively performed on a wide material, it is not necessary to perform it for each semiconductor element. Man-hours can be significantly reduced. Further, since the connection method is thermocompression bonding, the subsequent heat treatment step can be omitted.

(2) According to the above method, since the thin film of the conductive adhesive functions, the amount of the conductive adhesive used can be reduced as compared with the conventional method.

(3) Since the conductive adhesive applied on the terminal member is not higher than the electrode, it is not necessary to increase the thickness of the surface coating material more than necessary.

(4) According to the above method, since a conductive adhesive containing a metal such as Ag which is not easily corroded can be used for the connection surface as in the conventional example, long-term reliability can be secured. At the same time, since the terminal member formed of a metal such as copper that is easily oxidized can be protected over the entire surface, oxidation due to heat treatment during the manufacturing process and adverse effects due to oxidation after manufacturing can be prevented. You can secure more reliability than that obtained in.

Further, in the present invention, the step of applying at least one kind of first conductive adhesive to the metal thin wire in advance and drying the electrode, and the photovoltaic power generation by pressure bonding, thermocompression bonding or heating of the metal thin wire. Fixing on the surface of the light receiving surface of the element, and fixing on the surface of the light receiving surface of the photovoltaic element, and collecting the power collected by the electrode on the surface of the photovoltaic element It is manufactured in the step of fixing also on the surface of the terminal member for transmitting electric power to the outside, and the terminal member is manufactured in the step of applying the second conductive adhesive in advance to at least the portion fixing the electrode. As a result, the following two items became feasible.

(1) The step of applying a conductive adhesive on the terminal member can be provided off-line, separately from the step of forming the electrode. As a result, the work efficiency per unit time can be increased, and the cost of the commercialization process can be reduced.

(2) According to the above method, the individual electrodes are
At the same time, since they are fixed on the surface of the light receiving surface of the photovoltaic element by batch processing, the fixing degree of each contact portion is made uniform, and the reliability of the contact portions is also increased. Further, since the assembling process can be simplified by the above method, the cost can be reduced.

As described above, according to the present invention, the manufacturing process of the photovoltaic element can be simplified, the manufacturing apparatus can be simplified, and the materials used such as the conductive adhesive and the surface coating material can be reduced. The manufacturing cost can be reduced. In addition, high reliability that enables long-term use commensurate with initial investment can be realized.

[0032]

Embodiments Embodiments of the present invention will be described below.

(Semiconductor Layer) The semiconductor layer is an amorphous semiconductor,
The material is not particularly limited as long as it is a material capable of generating a photoelectromotive force such as a crystalline semiconductor or a compound semiconductor.

(Terminal Member) As the terminal member, a metal having a low volume resistivity is preferably used, and for example, copper, silver, aluminum, nickel or the like can be used. In particular, it is preferable to use a metal containing copper as a component. The reason is that the low-resistance terminal member can be formed inexpensively, and the loss accompanying power transmission can be minimized, so that a large output can be obtained with a small area and the manufacturing cost can be suppressed.

(First Conductive Adhesive) As the first conductive adhesive, a conductive adhesive containing carbon, low resistance metal, metal oxide or the like can be used. Particularly, it is preferable to use a polymer material to which carbon powder is added. The reason is that an ohmic connection can be formed with the photovoltaic element, and low resistance loss due to low contact resistance can be realized.

(Second Conductive Adhesive) As the second conductive adhesive, a conductive adhesive containing carbon, low resistance metal, metal oxide or the like can be used. Particularly, it is preferable to use a polymer resin to which a powder containing silver as a main component or a powder obtained by coating the surface of a metal or alloy with silver is added. The reason is that it is possible to form a connection that has low resistance and is resistant to deterioration such as oxidation. Further, as described above, when a metal containing copper as a component is used for the terminal member and a polymer resin containing carbon is used for the first conductive adhesive, the electrochemical reaction of the copper surface at the contact interface is performed. Oxidative deterioration (anodic oxidation) is likely to occur. However, by using as the second conductive adhesive a powder containing silver as a main component or a powder obtained by coating the surface of metal or alloy with silver is used as the second conductive adhesive, Oxidative deterioration can be prevented.

[0037]

Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1) In this example, a carbon powder is dispersed in a urethane resin as a first conductive adhesive, and a silver powder is dispersed in an epoxy resin as a second conductive adhesive. FIG. 1 shows the appearance of the photovoltaic element.

The photovoltaic element 101 in the figure comprises a substrate, an amorphous semiconductor which plays a role of photoelectric conversion, and a transparent conductive film as an electrode layer. The etching line 102 is a linear recess cut in the transparent conductive film,
Reference numeral 3 is an electrode for collecting electric power generated by the photovoltaic element. The terminal member 104 is used for making electrical connection with an adjacent photovoltaic element or for extracting electric power to the outside of the photovoltaic element, because the current collecting electrode finally delivers the electric power. In addition, the insulating member 105
Are provided to electrically insulate the terminal member 104 from the surface of the photovoltaic element. Further, the terminal member 106 forming the other pole of the photovoltaic element is mechanically and electrically connected to the conductive substrate of the photovoltaic element at the contact 106a.

As described in the section of the prior art, the etching line 102 is affected by the short circuit between the substrate and the transparent conductive film, which occurs when the outer circumference of the photovoltaic element is cut off. It is formed for the purpose of not reaching the effective light receiving range of. The etching line 102 is formed by applying an etching paste containing FeCl ₃ , AlCl ₃ or the like on the surface of a transparent conductive film by a method such as screen printing,
It was formed by removing the transparent conductive film by heating.

The collector electrode 103 has a first conductive adhesive, which will be described later, on the outer periphery of a copper wire having a diameter of 100 μm and a thickness of about 15 μm.
It was applied and dried at m, and after being aligned in the arrangement shown in FIG. 1, it was fixed to the surface of the photovoltaic element and the terminal member 104 by applying heat and pressure.

The first conductive adhesive used is one in which carbon powder having a particle diameter of several thousand liters is added to urethane resin at a weight ratio of 35% and dispersed by a shaker for a sufficient time. I was there.

FIG. 2 is a sectional view taken along the line XX 'in FIG. 1, and FIG. 3 is a sectional view taken along the line YY' in FIG.

In FIG. 2, the base 201 is a stainless steel plate having a thickness of 125 μm that supports the entire photovoltaic element. A back surface reflection layer is formed on the surface of the substrate 201, and a semiconductor layer 202 made of an amorphous silicon layer is formed on the surface of the back surface reflection layer. The back surface reflection layer is formed by sputtering method A
It is formed by sequentially depositing l and ZnO each with a thickness of several thousand Å. In addition, the semiconductor layer 2 made of an amorphous silicon layer
02 is an n-type, i
And p-type, n-type, i-type, and p-type layers were sequentially deposited. Thickness is 150Å, 4000Å, 100 respectively
It was Å, 100 Å, 800 Å, 100 Å. The transparent conductive film 203 is a film that functions as an electrode layer. By depositing In in an O ₂ atmosphere by a resistance heating method, an indium oxide thin film having a thickness of 700 Å was formed.

After that, the insulating member 105 is attached on the surface of the transparent conductive film 20. Further, the terminal member 104 is provided on the surface of the insulating member 105. As the insulating member 105, a polyester tape having a thickness of about several tens of μm, which is adhesively processed on the back surface, was used. Moreover, as the terminal member, a copper foil having a thickness of 125 μm and a width of 5.5 mm, the back surface of which was subjected to adhesive processing, was used. Here, the surface of the terminal member has a particle size of 1 to 3 μm in the epoxy resin.
The second conductive adhesive 20 in which about a silver powder is dispersed
4 is applied to a thickness of about 10 μm and dried at 80 ° C., which is sufficiently lower than the curing start temperature (about 150 ° C.) of the epoxy resin.

The above-mentioned coating step and drying step are carried out at the same time when the terminal member 104 is subjected to an adhesive treatment with a width of about 500 mm, and then slit and wound into a predetermined width (5.5 mm) and reeled. To make. In the manufacturing process of the photovoltaic element, a predetermined length was cut from the reel and attached to the position already described before use.

On the other hand, the transparent conductive film 203 is formed by continuously forming the collector electrode 103 on the surface of the transparent conductive film 203 and the surface of the conductive adhesive on the terminal member 105 by the thermocompression bonding process. And electrical connection with the conductive member 103 were established.

The collector electrode 103 has the same structure as in the prior art.
A first conductive adhesive 206 having a film thickness of about 15 μm is applied to the outer circumference of a copper wire 205 having a diameter of 100 μm, and the temperature is sufficiently lower than the curing start temperature 150 ° C. of the conductive adhesive 206 of 80 ° C.
The product was dried in, and wound on a bobbin for a predetermined length. The first conductive adhesive 206 used was a urethane resin in which carbon powder having a particle diameter of several thousand liters was dispersed at a weight ratio of 35%.

Then, the current collecting electrodes were cut out from the bobbin by a predetermined length, aligned at the positions shown in FIG. 1 at an appropriate pitch, and then heated and thermocompression bonded to the whole by a vacuum press. At this time, the heating temperature was set to be equal to or higher than the softening point of the first conductive adhesive 206 and the second conductive adhesive 204, and equal to or higher than the curing temperature of the two conductive adhesives. Specifically, heating at 150 ° C. for 2 minutes and pressurization (1 kgf / cm ² ) by a vacuum suction method were applied. As a result, the two conductive adhesives were able to form a low resistance and reliable mechanical and electrical bond after being melted and cured as shown in FIG.

Further, as shown in FIG. 2, the terminal member 106 of the other pole penetrates the transparent conductive film 203 and the semiconductor layer 202 in the region outside the etching line 102 to form the conductive substrate 201. , Contact points 106a are joined together. As a method of joining the contacts 106a, ultrasonic welding, resistance welding, arc welding, or the like can be used, but ultrasonic welding was used in this embodiment.

By configuring the photovoltaic element as described above, the collector electrode 103 collects the electric power generated in the semiconductor layer 202 from any place on the surface of the photovoltaic element through the transparent conductive film 203. Then, the terminal member 104
It has become possible to efficiently transport the material.

Table 1 shows the results of measuring the electrical initial characteristics required for a solar cell for the conventional photovoltaic element A and the photovoltaic element B of this example.

[0053]

[Table 1] In the conventional photovoltaic device A, the effective efficiency η is 7.7.
0%, series resistance is 28.3 Ωcm ² , while
In the photovoltaic device B of this example, the effective efficiency η is 7.
The resistance was 82% and the series resistance was 25.1 Ωcm ² . The higher the effective efficiency and the lower the series resistance, the more preferable,
It was found that the photovoltaic element B of this example was superior in initial element characteristics. From this, it is judged that the photovoltaic element having the two conductive adhesives in the combination shown in this example has no problem with the initial element characteristics.

For each of the above elements, the US SER
A temperature / humidity cycle test as presented in the I standard etc. was performed. In both devices, the deterioration rate was almost zero after 20 cycles, which was the standard, and no difference was observed. However, after 80 cycles, which greatly exceeds the standard, the deterioration rate of the conventional photovoltaic element A is 3.6%, whereas the deterioration rate of the photovoltaic element B of this example is 1.3%. And
The deterioration rate could be improved significantly. From this, it has been confirmed that the photovoltaic element having the two conductive adhesives in the combination shown in this example has sufficient long-term reliability.

In this example, copper was used as the core material of the current collecting electrode, but any metal having a volume resistivity within the range not impairing the intention of the present invention may be used. For example, a thin metal wire such as silver or nickel may be used. You can use it.

In this example, one kind of conductive adhesive is applied to the outer circumference of the copper wire, but two or more kinds of conductive adhesive may be applied in layers.

Example 2 In this example, the photovoltaic element C was formed by replacing the material of the first conductive adhesive and the material of the second conductive adhesive in Example 1. The other points were the same as in Example 1.

As the first conductive adhesive, 30% by weight of carbon black having a particle diameter of several hundred nm was added to an acrylic thermoplastic resin, and ME was added for viscosity adjustment.
A small amount of K was added and dispersed by a shaker for a sufficient time. The first conductive adhesive has a diameter of 100
A current collecting electrode was formed by applying it around a copper wire of μm and drying it at a temperature of 80 ° C.

The second conductive adhesive is the first
A silver paste in which a silver powder having a particle size of about 5 μm was dispersed in the same acrylic thermoplastic resin as that used in the conductive adhesive of was used. The second conductive adhesive is applied at a thickness of 100 μm on the surface of the copper foil, which is a terminal member, and then at 80 ° C.
Dried.

The current collecting electrode is connected to the electrode forming surface and the terminal member coated with the second conductive adhesive by a thermocompression bonding process. At that time, when it was heated at 150 ° C. for 2 minutes while applying a pressure of 1 kgf / cm ² , the acrylic resin in the terminal member portion was cured so as to melt each other,
It was possible to form low resistance and reliable mechanical and electrical junctions.

In the photovoltaic device C having the two conductive adhesives in the combination shown in this example, the initial efficiency η was 7.90% and the series resistance was 24.1 Ωcm ^2. (Table 1). That is, the first conductive adhesive was carbon black added to an acrylic thermoplastic resin, and the second conductive adhesive was a silver powder dispersed in the acrylic thermoplastic resin. It is judged that there is no problem with the initial device characteristics even if the silver paste is replaced. In addition, for the photovoltaic element C of this example, Example 1
As a result of performing the same temperature-humidity cycle test as described above, the deterioration rate after 80 cycles was suppressed to 0.8%. Therefore, in terms of long-term reliability, it was determined that a very good connection could be achieved.

Example 3 In this example, the photovoltaic element D was formed by replacing the material of the first conductive adhesive and the material of the second conductive adhesive in Example 1. The other points were the same as in Example 1.

As the first conductive adhesive, 30% by weight of carbon black having a particle diameter of several hundreds nm was added to an acrylic thermoplastic resin, and ME was added to adjust the viscosity.
A small amount of K was added and dispersed by a shaker for a sufficient time. Separately from the first conductive adhesive, a carbon paste was prepared in which fine particles of carbon having a particle diameter of several hundred nm were dispersed in an epoxy resin at a ratio of 35% by weight.

First, the above epoxy-based carbon paste was applied to the periphery of a copper wire having a diameter of 100 μm to a thickness of 5 μm and cured at 150 ° C., and then the first conductive adhesive was applied to the periphery of a copper wire having a diameter of 100 μm to 10 μm. A current collecting electrode was formed by applying a coating solution having a thickness of 80 ° C. and drying at a temperature of 80 ° C. Here, the reason why the epoxy-based carbon paste is provided between the copper wire and the first conductive adhesive is to prevent metal ion migration from the copper wire.

As the second conductive adhesive, the first
A silver paste in which a silver powder having a particle size of about 5 μm was dispersed in the same acrylic thermoplastic resin as that used in the conductive adhesive of was used. The second conductive adhesive is applied at a thickness of 100 μm on the surface of the copper foil, which is a terminal member, and then at 80 ° C.
Dried.

The current collecting electrode is connected to the electrode formation surface and the terminal member coated with the second conductive adhesive by a thermocompression bonding process. At that time, when it was heated at 150 ° C. for 2 minutes while applying a pressure of 1 kgf / cm ² , the acrylic resin in the terminal member portion was cured so as to melt each other
It was possible to form low resistance and reliable mechanical and electrical junctions.

In the photovoltaic device D having the two conductive adhesives in the combination shown in this example, the result that the effective efficiency η is 7.88% and the series resistance is 24.6 Ωcm ² is obtained at the initial stage. (Table 1). That is, the first conductive adhesive was carbon black added to an acrylic thermoplastic resin, and the second conductive adhesive was a silver powder dispersed in the acrylic thermoplastic resin. Even when an epoxy-based carbon paste is provided between the copper wire and the first conductive adhesive instead of the silver paste, it is determined that there is no problem with the initial element characteristics.

The photovoltaic device D of this example was subjected to the same temperature and humidity cycle test as in Example 1, and as a result, the deterioration rate after 80 cycles was suppressed to 0.7%. Therefore, in terms of long-term reliability, a very excellent connection could be achieved.

[0069]

【The invention's effect】

(Claim 1) As described above, according to the invention of claim 1, the following effects can be obtained.

(1) It is possible to omit the step of applying a conductive adhesive after forming the above-mentioned electrodes, which is conventionally required. As a result, it is possible to significantly reduce the cost of the manufacturing process.
Needless to say, the step of applying the conductive adhesive on the terminal member is necessary (off-line), but since the step can be collectively performed on a wide material, it is not necessary to perform it for each semiconductor element. Man-hours can be significantly reduced. Further, since the connection method is thermocompression bonding, the subsequent heat treatment step can be omitted.

(2) According to the above method, since the thin film of the conductive adhesive functions, the amount of the conductive adhesive used can be reduced as compared with the conventional method.

(3) Since the conductive adhesive applied on the terminal member does not become higher than the electrode, it is not necessary to increase the thickness of the surface coating material more than necessary.

(4) According to the above method, since a conductive adhesive containing a metal such as Ag which is not easily corroded can be used for the connection surface as in the conventional example, long-term reliability can be secured. At the same time, the entire surface of the terminal member formed of a metal such as copper that easily oxidizes can be protected, so that it is possible to prevent the adverse effects of oxidation due to heat treatment during the manufacturing process and oxidation after manufacturing. You can secure more reliability than you can expect.

(Claim 5) According to the invention of claim 5, the following effects can be obtained.

(1) The step of applying a conductive adhesive on the terminal member can be provided off-line, separately from the step of forming the electrode. As a result, the work efficiency per unit time can be increased, and the cost of the commercialization process can be reduced.

(2) According to the above method, the individual electrodes are
At the same time, since they are fixed on the surface of the light receiving surface of the photovoltaic element by batch processing, the fixing degree of each contact portion is made uniform, and the reliability of the contact portions is also increased. Further, since the assembling process can be simplified by the above method, the cost can be reduced.

As described above, according to the present invention, the manufacturing process of the photovoltaic element can be simplified, the manufacturing apparatus can be simplified, and the materials used such as the conductive adhesive and the surface coating material can be reduced. Cost can be reduced. In addition, high reliability that enables long-term use commensurate with initial investment can be realized.

[Brief description of drawings]

FIG. 1 is a schematic view showing the appearance of a photovoltaic element according to this example.

FIG. 2 is a schematic diagram showing a cross section of a portion XX ′ in FIG.

FIG. 3 is a schematic view showing a cross section of a portion YY ′ in FIG.

FIG. 4 is a schematic view showing an appearance of a photovoltaic element according to a conventional example.

[Explanation of symbols]

 101 photovoltaic element, 102, 401 etching line, 103, 402 current collecting electrode, 104, 403 terminal member, 105, 404 insulating member, 106 other pole terminal member, 106a junction point of other pole terminal member, 201 substrate, 202 semiconductor layer, 203 transparent conductive film, 204 second conductive adhesive, 205 copper wire, 206 first conductive adhesive, 405 conductive adhesive

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kenji Takada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (5)

[Claims] 1. A photovoltaic element having a semiconductor layer for photoelectric conversion and an electrode for collecting electric power generated in the semiconductor layer, wherein the electrode is at least one kind of first conductive material in advance. Adhesive applied and dried metal fine wire is crimped,
It is fixed on the surface of the light receiving surface of the photovoltaic element by thermocompression bonding or heating, and is for transmitting the electric power collected by the electrode to the outside of the element on the surface of the photovoltaic element. A terminal member, the electrode is fixed on the surface of the light-receiving surface of the photovoltaic element and also fixed on the surface of the terminal member, and at least a portion of the terminal member where the electrode is fixed. Is a second conductive adhesive applied in advance, and is a photovoltaic element. 2. The photovoltaic element according to claim 1, wherein the terminal member is made of a metal containing at least copper as a component. 3. The photovoltaic element according to claim 1, wherein the first conductive adhesive is formed by adding carbon powder to a polymer resin. 4. The second conductive adhesive is made of a polymer resin to which a powder containing silver as a main component or a powder obtained by coating the surface of a metal or alloy with silver is added. The photovoltaic element according to claim 1. 5. A method of manufacturing a photovoltaic element having a semiconductor layer for photoelectric conversion and an electrode for collecting power generated in the semiconductor layer, wherein at least one kind of the electrode is preliminarily formed on a thin metal wire. A step of applying and drying the first conductive adhesive, and a step of fixing the metal thin wire on the surface of the light receiving surface of the photovoltaic element by pressure bonding, thermocompression bonding or heating.
While fixed on the surface of the light receiving surface of the photovoltaic element,
At least fixing on the surface of the terminal member for transmitting the electric power collected by the electrode on the surface of the photovoltaic element to the outside of the element, the terminal member being at least the A method of manufacturing a photovoltaic element, comprising a step of previously applying a second conductive adhesive to a portion for fixing an electrode.