JPH06204523A - Removal of short-circuit part of photoelectric converter - Google Patents

Abstract

PURPOSE:To easily remove a current short-circuited part with a low cost even in the case of a large area. CONSTITUTION:An opposite electrode 105 and a photoelectric converter are first dipped in electrolyte 106, a voltage of about 2.5V is applied between the electrode 105 as a cathode and a conductive board 101 of the converter as an anode, and an electrolytic reaction is conducted. Thus, a voltage is applied between the electrode 105 as the cathode and the board 101 as the anode from a DC power source 107, electrons flow from the anode to the power source, then from the power source to the electrode 105, the reaction occurs, and transparent conductive oxide of a short-circuit part in contact with the electrolyte is oxidized with halogen ions. Thus, the part is removed and covered with electrically insulating substance. Since no current flows in a part which is not short-circuited, the oxide is not removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing a short circuit portion formed in a solar cell which is a photoelectric conversion device.

[0002]

2. Description of the Related Art Among various solar cells, amorphous silicon solar cells can be manufactured in a large area and have a low manufacturing cost, so they are widely put into practical use. Occurrence of many places,
It caused the deterioration of the function of the solar cell.

As means for removing a short-circuited portion of a solar cell,
For example, as disclosed in Japanese Examined Patent Publication No. 62-53958, a method of removing the short-circuited portion by irradiating it with a laser beam has been proposed. However, this method has the drawbacks that the short-circuited portion must be determined before the irradiation with the energy beam, and if there are many short-circuited portions, it takes a lot of processing time depending on the number. .

In US Pat. No. 4,451,970 and JP-A-59-94473, there is a short-circuit current area of a photovoltaic device formed by the presence of a semiconductor layer and a conductive light-transmitting material film on a substrate. A method has been proposed in which a film of an electrolytic solution is formed on the conductive light-transmitting material film, and a voltage is applied to the substrate so as to maintain the electrolyte positive, and the short-circuit current path is removed.

Further, the documents of the above-mentioned specification and publication also describe a technique of depositing an insulating material in the area where the short-circuit current path is removed. However, this technique cannot be carried out because the cathode and the anode are in contact with the electrolyte and a positive charge cannot be applied to the entire electrolyte.

The latest prior art in this field investigated by the applicant is, as disclosed in US Pat. No. 4,729,970, a transparent conductive oxide as an electrode.
There are techniques for filling defects in the short-circuit current path of thin-film electronic devices. According to this, an electric current is passed between a semiconductor and a counter electrode in a solution containing Lewis acid such as aluminum chloride, zinc chloride, second steel chloride, and titanium tetrachloride to oxidize or reduce the transparent conductive oxide. However, the resistance is increased by changing the stoichiometric ratio of the transparent conductive oxide.

[0007]

The above-mentioned US Pat. No. 4729
In order to confirm the effect of the technique disclosed in Japanese Patent No. 970, an aqueous solution of zinc chloride, stannic chloride or stannous chloride is used to make a solar cell substrate a negative electrode (cathode) and a counter electrode a positive electrode (anode). ), The short-circuited part of the device was not repaired, and a metal salt (Z
It has been reported that, as a result of the precipitation of (n, Sn), the number of short-circuited locations increased.

As described above, the conventional method for removing the current short-circuited portion of the solar cell has a problem in production efficiency and working conditions. Therefore, in order to solve this problem, it is desired to develop a method that can be applied to a large-area solar cell and can remove a current short circuit portion with sufficient production efficiency.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method capable of easily and inexpensively removing a current short circuit portion even in a large area.

[0010]

In order to achieve the above-mentioned object, the present invention provides that a semiconductor layer and a transparent conductive oxide film forming a photoelectric conversion element are sequentially formed on a conductive substrate,
In the method for removing a short-circuited portion of a photoelectric conversion device having a short-circuited portion between the conductive substrate and the transparent conductive oxide film, a standard electrode potential which is a redox potential of negative ions contained is 0.
Immersing the photoelectric conversion element in an electrolytic solution that is positive or positive,
A step of removing the short-circuited portion by electrolytic oxidation using the conductive substrate as an anode and a counter electrode as a cathode; a step of applying a lipophilic curable resin coating material on the transparent conductive oxide film; and the curable resin Includes a step of forming a collector electrode by applying a hydrophilic conductive coating material on the coating film of the coating material, a step of curing the lipophilic curable resin coating material, and a step of drying the hydrophilic conductive coating material It is characterized by

In this case, it is desirable that the negative ions contained in the electrolytic solution are halogen ions or halogen-containing ions.

The lipophilic curable resin is preferably a thermosetting resin.

Further, it is desirable that the hydrophilic conductive paint comprises a cross-linking resin, conductive particles and an emulsifier.

Further, in the electrolytic oxidation, the current density of the anode is 0.1 to 5.0 μA / cm ² , and the electrolysis time is 1 to 3
It is desirable that the temperature is 00 seconds and the temperature of the electrolytic solution is in the range of -5 to + 95 ° C.

[0015]

In order to remove the short-circuited portion by using the electrolytic oxidation device as shown in FIG. 1, first, the counter electrode 105 and the photoelectric conversion device are immersed in the electrolytic solution 106, and the counter electrode 105 is used as the cathode to perform the photoelectric conversion. Using the conductive substrate 101 of the device as an anode, a voltage of about 2.5 V is applied between the two to cause an electrolytic reaction. As a result, the counter electrode 105 serving as the cathode and the substrate 101 serving as the anode are driven by the DC power supply 107.
A voltage is applied between the anode and the electron, and the electrons flow from the anode to the DC power source, and then from the DC power source to the counter electrode 105, an electrolytic reaction occurs, and the transparent conductive oxide in the short-circuit portion that comes into contact with the electrolytic solution is changed by the halogen ion. Since it is oxidized, it is eluted into the electrolytic solution as metal ions. That is, the transparent conductive oxide 103 in the short-circuited portion is removed, and no current flows in the portion not short-circuited, so the transparent conductive oxide is not removed.

[0016]

(Example 1) FIG. 3 shows the structure of a solar cell 300 according to the present invention after removing a short circuit, where 301 is a conductive substrate, 302 is a semiconductor layer, and 303 is transparent conductive. The oxide layer, 304, is a current short circuit portion that has become a hole.

FIG. 2 shows the structure of the solar cell 200 before removal of the short circuit portion, and 201 is a conductive substrate.
202 is a semiconductor layer, 203 is a transparent conductive oxide layer, 20
4 is a current short circuit part.

FIG. 1 shows an electrolytic oxidation device for removing a current short circuit portion of a solar cell 100, 101 is a conductive substrate, 102 is a semiconductor layer, 103 is a transparent conductive oxide layer, and 104 is a transparent conductive oxide layer. Coating film such as acetyl cellulose, 1
Reference numeral 05 is a cathode electrode, 106 is an electrolytic solution, 107 is a DC power source, and 108 is an electrolytic cell. In this device, in order to efficiently cause the electrolytic reaction only in the short-circuited portion, when the conductive substrate 101 on the anode electrode side is in direct contact with the electrolytic solution, it is coated with an acetyl cellulose film or the like. It is desirable to avoid direct contact with the electrolyte.

In order to remove the short-circuited portion by using the electrolytic oxidation device, first, the counter electrode 105 and the photoelectric conversion device are immersed in the electrolytic solution 106, and the counter electrode 105 is used as a cathode, and the conductive substrate of the photoelectric conversion device is used. Using 101 as an anode, a voltage of about 2.5 V was applied between the two to cause an electrolytic reaction.

A voltage is applied between the counter electrode 105 and the substrate 101 by the DC power supply 107, and the electrons flow from the anode to the DC power supply, and then from the DC power supply 107 to the counter electrode 10.
5, the electrolytic reaction occurred, and the transparent conductive oxide in the short-circuit portion that was in contact with the electrolytic solution was oxidized by the halogen ions, so that it was eluted into the electrolytic solution as metal ions. That is, the transparent conductive oxide 103 in the short-circuited portion was removed, and no current flowed in the non-short-circuited portion, so the transparent conductive oxide was not removed.

When the electrolytic oxidation reaction was continued, the short circuit portion of the semiconductor layer 102 was also eluted in the electrolytic solution. After the electrolytic oxidation treatment, the solar cell was thoroughly washed with water and dried.

In the solar cell 400 shown in FIG. 4, the lipophilic curable resin coating is applied to the surface of the transparent conductive oxide layer 403, and the lipophilic curable resin coating is applied to the holes left after the current short-circuit is removed. The state where the coating film 404 is filled is shown. In FIG. 4, 401 is a conductive substrate and 402 is a semiconductor layer.

The solar cell 500 shown in FIG. 5 shows a state in which a hydrophilic conductive paint is applied to form a collector electrode 505 on a coating film 504 of a lipophilic curable resin paint. In the figure, 501 is a conductive substrate, 502 is a semiconductor layer,
503 is a transparent conductive oxide layer.

The coating film 504 of the lipophilic curable resin coating material is spread by the invasion of the hydrophilic conductive coating material 505, but the portion filled in the holes of the short circuit portion remains as it is.

In FIG. 5, the coating layer 505 of the hydrophilic conductive paint is drawn smaller than the pores.
In practice, the diameter of the holes is 1-2 μm and the coating width is 100 μm.
It is more than μm, and the lipophilic curable resin paint is trapped in the pores.

Next, when the lipophilic curable resin coating material is a thermosetting resin, the curable resin is cured by heating the solar cell coated with the above two kinds of coating materials, and the like. The conductive paint is dried.

(Embodiment 2) FIG. 7 shows an example of the structure of a solar cell 700 after removal of a short circuit portion. In the figure, 701 is a metal substrate (stainless steel substrate), 702 is a back electrode (silver), 703 is zinc oxide of a silver diffusion preventing layer, 70
4 is an n-type amorphous silicon layer doped with phosphorus, 7
Reference numeral 05 is a non-doped (i-type) amorphous silicon / germanium layer, 706 is a P-type amorphous silicon layer doped with boron, 707 is a non-dope amorphous silicon layer, and 708 is a stannic oxide transparent conductive oxide layer.

In this embodiment, the surface of the metal substrate of the solar cell is coated with an acetyl cellulose film, the electrolytic cell as shown in FIG. 1 is used, and the electrolytic solution has a concentration of 0.01 mo1 /
1 of sodium fluoride aqueous solution was used, and a platinum plate was used as a counter electrode. A conductive substrate is used as an anode, a platinum plate is used as a cathode, a DC voltage is applied between both electrodes, and the current density per anode electrode is set to 1.0 μA / cm ² for 30 seconds.
The electrolysis reaction was carried out in between. Then, the voltage application was stopped and the solar cell was washed with water.

Next, the solar cell 600 was coated with a lipophilic curable resin coating material using a coating tank as shown in FIG. A thermosetting acrylic resin paint was used as the paint. The viscosity of the coating material and the coating speed were adjusted so that the thickness of the coating film was about 1 μm. In FIG. 6, 601 is a paint container, 602
Is a paint, and 603 is a vertical drive mechanism.

Next, the solar cell coated with the thermosetting acrylic resin coating is fixed horizontally with the coated surface facing upward, and a polyvinyl acetate-based hydrophilic conductive silver paste is placed on the coated surface. Applied from. The viscosity of the silver paste is about 800 cps
Then, after coating, leave at room temperature for 30 minutes, and then at 150 ° C for 6
Heat for 0 minutes.

FIGS. 10 (a) and 10 (b) show the solar cell A before and after the removal processing of the current short-circuited portion, respectively.
Ml. 5 shows current-voltage (IV) characteristic measurement data when light irradiation of 5, 100 mw / cm ² was performed.

FIG. 9 shows a circuit for measuring the IV characteristic. In FIG. 9, 900 is light, 901 is a solar cell, 902 is a voltmeter, 903 is an ammeter, and 904 is a DC power supply.

From FIGS. 10 (a) and 10 (b), it is apparent that the dark current and the light (irradiation) current increase after the removal processing of the current short-circuited portion, and the effect of removing the current short-circuited portion is shown. I found out that

(Embodiment 3) FIG. 8 shows an example of the structure of the solar cell 800 after removing the short-circuited portion in this experimental example. In the figure, 801 is a stainless steel substrate, 802 is Ag,
803 is ZnO, 804 is phosphorus-doped n-type amorphous silicon-germanium, 805 is boron-doped p ⁺ -type amorphous silicon, 806 is non-doped amorphous silicon, and 807 is In ₂ O ₃ —Sn.
It is O ₂ .

The solar cell 800 having the above structure is
The stainless steel substrate 801 was used as an anode electrode, and the graphite electrode was inserted as a counter electrode cathode into the electrolytic cell. As the electrolytic solution, a 0.05 mol / l aqueous solution of sodium borofluoride was used. Current density per anode electrode is 0.5 μA
/ Cm ² and the electrolytic reaction was performed for 40 seconds. After that, the electrolytic reaction was stopped and the solar cell was washed with water.

Next, as in Example 2, the coating tank shown in FIG. 6 was used to apply a lipophilic curable resin coating material to the solar cell, which was an unsaturated polyester resin coating material. . The coating film was adjusted in viscosity and coating speed so that the thickness was about 1 μm.

Next, the solar cell coated with the unsaturated polyester resin coating is fixed horizontally with the coating surface facing upward,
A polyvinyl acetate-based hydrophilic conductive silver paste was applied from above the applied surface. The paste has a viscosity of about 800c
ps, leave at room temperature for 30 minutes after application, then 120 ° C
Heated for 60 minutes.

For the solar cell of this example, the IV characteristics during light irradiation were measured in the same manner as in Example 2 above. The IV characteristics before and after the short-circuit removal processing are as shown in FIGS. 11A and 11B, respectively, and it can be seen that the dark current and the light (irradiation) current increase after the processing.

[0039]

As described above, according to the present invention, it is possible to easily and surely remove a short-circuit portion including a large number of short-circuit portions, improve the production efficiency of a solar cell, and reduce the manufacturing cost. I can contribute. In addition, since the removal process and equipment can be simplified, the manufacturing cost can be reduced and the yield can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of an electrolytic cell for carrying out the method of the present invention.

FIG. 2 is a schematic cross-sectional view of a solar cell having a short circuit portion.

FIG. 3 is a schematic cross-sectional view after the transparent conductive oxide and the semiconductor layer in the short circuit portion are removed.

FIG. 4 is a schematic cross-sectional view after a lipophilic curable resin has been applied.

FIG. 5 is a schematic cross-sectional view after a hydrophilic conductive paint is applied.

FIG. 6 is a cross-sectional view showing a configuration example of a coating tank.

FIG. 7 is a schematic cross-sectional view of a solar cell according to a second embodiment.

FIG. 8 is a schematic sectional view of a solar cell according to a third embodiment.

FIG. 9 is a circuit diagram of a measurement system for measuring current-voltage characteristics of a solar cell.

FIG. 10 is a graph showing current-voltage characteristics before and after the treatment of the solar cell according to the second embodiment.

FIG. 11 is a graph showing current-voltage characteristics before and after the treatment of the solar cell according to the third embodiment.

[Explanation of symbols]

100, 200, 300, 400, 500, 700, 8
00 solar cell (photoelectric conversion device), 101, 201, 301 conductive substrate, 102, 202, 302, 402 semiconductor layer, 103, 203, 303, 403, 503 transparent conductive oxide layer, 204 current short-circuit portion, 703 803 shunt prevention layer 601 paint container, 404 lipophilic curable resin coating film, 505 hydrophilic conductive paint.

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[Procedure amendment]

[Submission date] August 13, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Method for removing short-circuited portion of photoelectric conversion device

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing a short circuit portion formed in a solar cell which is a photoelectric conversion device.

[0002]

2. Description of the Related Art Among various solar cells, amorphous silicon solar cells can be manufactured in a large area and have a low manufacturing cost, so they are widely put into practical use. Occurrence of many places,
It caused the deterioration of the function of the solar cell.

As means for removing a short-circuited portion of a solar cell,
For example, as disclosed in Japanese Examined Patent Publication No. 62-53958, a method of removing the short-circuited portion by irradiating it with a laser beam has been proposed. However, this method has the drawbacks that the short-circuited portion must be determined before the irradiation with the energy beam, and if there are many short-circuited portions, it takes a lot of processing time depending on the number. .

In US Pat. No. 4,451,970 and JP-A-59-94473, a photovoltaic cell device formed by the presence of a semiconductor layer and a conductive light transmitting material film on a substrate. A method of forming a film of an electrolytic solution on the conductive light-transmitting material film in the short-circuit current area, applying a voltage to the substrate to maintain the electrolyte positive, and removing the short-circuit current path is proposed. ing.

Further, the documents of the above-mentioned specification and publication also describe a technique of depositing an insulating material in the area where the short-circuit current path is removed. However, this technique cannot be carried out because the cathode and the anode are in contact with the electrolyte and a positive charge cannot be applied to the entire electrolyte.

The most recent prior art in this field investigated by the applicant is, as disclosed in US Pat. No. 4,729,970, using a transparent conductive oxide as an electrode for a short-circuit current path of a thin film electronic device. There is a method of filling defects. According to this, an electric current is passed between a semiconductor and a counter electrode in a solution containing a Lewis acid such as aluminum chloride, zinc chloride, stannic chloride, or titanium tetrachloride to oxidize or reduce the transparent conductive oxide. However, the resistance is increased by changing the stoichiometric ratio of the transparent conductive oxide.

[0007]

The above-mentioned US Pat. No. 472.
In order to confirm the effect of the technique disclosed in Japanese Patent No. 9970, an aqueous solution of zinc chloride, stannic chloride or stannous chloride is used to make a solar cell substrate a negative electrode (cathode) and a counter electrode a positive electrode (anode). It is reported that the short-circuited part of the device is not repaired and the metal salt metal (Zn, Sn) is deposited on the short-circuited part, resulting in an increase in the short-circuited part.

As described above, the conventional method for removing the current short-circuited portion of the solar cell has a problem in production efficiency and working conditions. Therefore, in order to solve this problem, it is desired to develop a method that can be applied to a large-area solar cell and can remove a current short circuit portion with sufficient production efficiency.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method capable of easily and inexpensively removing a current short circuit portion even in a large area.

[0010]

In order to achieve the above-mentioned object, the present invention provides that a semiconductor layer and a transparent conductive oxide film forming a photoelectric conversion element are sequentially formed on a conductive substrate,
In the method for removing a short-circuited portion of a photoelectric conversion device having a short-circuited portion between the conductive substrate and the transparent conductive oxide film, a standard electrode potential which is a redox potential of negative ions contained is 0.
Immersing the photoelectric conversion element in an electrolytic solution that is positive or positive,
A step of removing the short-circuited portion by electrolytic oxidation using the conductive substrate as an anode and a counter electrode as a cathode; a step of applying a lipophilic curable resin coating material on the transparent conductive oxide film; and the curable resin Includes a step of forming a collector electrode by applying a hydrophilic conductive coating material on the coating film of the coating material, a step of curing the lipophilic curable resin coating material, and a step of drying the hydrophilic conductive coating material It is characterized by

In this case, the negative ions contained in the electrolytic solution are preferably halogen ions or halogen-containing ions.

The lipophilic curable resin is preferably a thermosetting resin.

Further, it is desirable that the hydrophilic conductive paint comprises a cross-linking resin, conductive particles and an emulsifier.

Further, in the electrolytic oxidation, the current density of the anode is 0.1 to 5.0 μA / cm ² , and the electrolysis time is 1 to 3.
It is desirable that the electrolyte temperature is 00 sec and the electrolyte temperature is in the range of -5 to + 95 ° C.

[0015]

In order to remove the short-circuited portion by using the electrolytic oxidation device as shown in FIG. 1, first, the counter electrode 105 and the photoelectric conversion device are immersed in the electrolytic solution 106, and the counter electrode 105 is used as the cathode to perform the photoelectric conversion. Using the conductive substrate 101 of the device as an anode, a voltage of about 2.5 V is applied between them to cause an electrolytic reaction. As a result, a voltage is applied between the counter electrode 105, which is the cathode, and the substrate 101, which is the anode, by the DC power supply 107, and electrons flow from the anode to the DC power supply, and then from the DC power supply to the counter electrode 105, and an electrolytic reaction occurs. Since the transparent conductive oxide at the short-circuited portion that comes into contact with the electrolytic solution is oxidized by the halogen ions, it is eluted into the electrolytic solution as metal ions. That is, the transparent conductive oxide 103 in the short-circuited portion is removed, and no current flows in the portion not short-circuited, so the transparent conductive oxide is not removed.

[0016]

(Example 1) FIG. 3 shows the structure of a solar cell 300 according to the present invention after removing a short circuit, where 301 is a conductive substrate, 302 is a semiconductor layer, and 303 is transparent conductive. The oxide layer, 304, is a current short circuit portion that has become a hole.

FIG. 2 shows the structure of the solar cell 200 before removal of the short circuit portion, and 201 is a conductive substrate.
202 is a semiconductor layer, 203 is a transparent conductive oxide layer, 20
4 is a current short circuit part.

FIG. 1 shows an electrolytic oxidation device for removing a current short circuit portion of a solar cell 100, 101 is a conductive substrate, 102 is a semiconductor layer, 103 is a transparent conductive oxide layer, and 104 is a transparent conductive oxide layer. Coating film such as acetyl cellulose, 1
Reference numeral 05 is a cathode electrode, 106 is an electrolytic solution, 107 is a DC power source, and 108 is an electrolytic cell. In this device, in order to efficiently cause the electrolytic reaction only in the short-circuited portion, when the conductive substrate 101 on the anode electrode side is in direct contact with the electrolytic solution, it is coated with an acetyl cellulose film or the like. It is desirable to avoid direct contact with the electrolyte.

In order to remove the short-circuited portion by using the electrolytic oxidation device, first, the counter electrode 105 and the photoelectric conversion device are immersed in the electrolytic solution 106, and the counter electrode 105 is used as a cathode, and the conductive substrate of the photoelectric conversion device is used. Using 101 as an anode, a voltage of about 2.5 V was applied between the two to cause an electrolytic reaction.

A voltage is applied between the counter electrode 105 and the substrate 101 by the DC power supply 107, and the electrons flow from the anode to the DC power supply, and then from the DC power supply 107 to the counter electrode 10.
5, the electrolytic reaction occurred, and the transparent conductive oxide in the short-circuit portion that was in contact with the electrolytic solution was oxidized by the halogen ions, so that it was eluted into the electrolytic solution as metal ions. That is, the transparent conductive oxide 103 in the short-circuited portion was removed, and no current flowed in the non-short-circuited portion, so the transparent conductive oxide was not removed.

When the electrolytic oxidation reaction was continued, the short circuit portion of the semiconductor layer 102 was also eluted in the electrolytic solution. After the electrolytic oxidation treatment, the solar cell was thoroughly washed with water and dried.

In the solar cell 400 shown in FIG. 4, the lipophilic curable resin coating is applied to the surface of the transparent conductive oxide layer 403, and the lipophilic curable resin coating is applied to the holes left after the current short-circuit is removed. The state where the coating film 404 is filled is shown. In FIG. 4, 401 is a conductive substrate and 402 is a semiconductor layer.

The solar cell 500 shown in FIG. 5 shows a state in which a hydrophilic conductive paint is applied to form a collector electrode 505 on a coating film 504 of a lipophilic curable resin paint. In the figure, 501 is a conductive substrate, 502 is a semiconductor layer,
503 is a transparent conductive oxide layer.

The coating film 504 of the lipophilic curable resin coating material is spread by the invasion of the hydrophilic conductive coating material 505, but the portion filled in the holes of the short circuit portion remains as it is.

In FIG. 5, the coating layer 505 of the hydrophilic conductive paint is drawn smaller than the pores.
Actually, the diameter of the holes is 1-2 μm, and the coating width is 100 μm.
It is more than μm, and the lipophilic curable resin paint is trapped in the pores.

Next, when the lipophilic curable resin coating material is a thermosetting resin, the curable resin is cured by heating the solar cell coated with the above two kinds of coating materials, and the like. The conductive paint is dried.

(Embodiment 2) FIG. 7 shows an example of the structure of a solar cell 700 after removal of a short circuit portion. In the figure, 701 is a metal substrate (stainless steel substrate), 702 is a back electrode (silver), 703 is zinc oxide of a silver diffusion preventing layer, 70
4 is an n-type amorphous silicon layer doped with phosphorus, 7
Reference numeral 05 is a non-doped (i-type) amorphous silicon-germanium layer, 706 is a p-type amorphous silicon layer doped with boron, 707 is a non-doped amorphous silicon layer, and 708 is a transparent conductive oxide layer of stannic oxide.

In this example, the metal substrate surface of the solar cell was coated with an acetyl cellulose film, the electrolytic cell as shown in FIG. 1 was used, and the concentration of the electrolyte solution was 0.01 mol / min.
1 of sodium fluoride aqueous solution was used, and a platinum plate was used as a counter electrode. A conductive substrate is used as an anode, a platinum plate is used as a cathode, a DC voltage is applied between both electrodes, and the current density per anode electrode is set to 1.0 μA / cm ² for 30 seconds.
The electrolysis reaction was performed between. Then, the voltage application was stopped and the solar cell was washed with water.

Next, the solar cell 600 was coated with a lipophilic curable resin coating material using a coating tank as shown in FIG. A thermosetting acrylic resin paint was used as the paint. The viscosity of the coating material and the coating speed were adjusted so that the thickness of the coating film was about 1 μm. In FIG. 6, 601 is a paint container, 602
Is a paint, and 603 is a vertical drive mechanism.

Next, the solar cell coated with the thermosetting acrylic resin coating is fixed horizontally with the coating surface facing upward, and a polyvinyl acetate-based hydrophilic conductive silver paste is coated on the coating surface. did. The viscosity of the silver paste is about 800 cps,
After coating, the mixture was left at room temperature for 30 minutes and then heated at 150 ° C. for 60 minutes.

FIGS. 10 (a) and 10 (b) show the solar cell A before and after the removal processing of the current short-circuited portion, respectively.
It shows the current-voltage (IV) characteristic measurement data when M1.5, 100 mW / cm ² was irradiated with light.

FIG. 9 shows a circuit for measuring the IV characteristic. In FIG. 9, 900 is light, 901 is a solar cell, 902 is a voltmeter, 903 is an ammeter, and 904 is a DC power supply.

From FIGS. 10 (a) and 10 (b), it is apparent that the dark current and the light (irradiation) current increase after the removal processing of the current short-circuited portion, and the effect of removing the current short-circuited portion is shown. I found out that

(Embodiment 3) FIG. 8 shows an example of the structure of the solar cell 800 after removing the short-circuited portion in this experimental example. In the figure, 801 is a stainless steel substrate, 802 is Ag,
803 is ZnO, 804 is phosphorus-doped n-type amorphous silicon / germanium, 805 is boron-doped p ⁺ -type amorphous silicon, 806 is non-doped amorphous silicon, and 807 is In ₂ O ₃ —SnO.
_{Is 2} .

The solar cell 800 having the above structure is
The stainless steel substrate 801 was used as an anode electrode, and the graphite electrode was inserted as a counter electrode cathode into the electrolytic cell. A 0.05 mol / l aqueous solution of sodium fluoride was used as the electrolytic solution. Current density per anode electrode is 0.5 μA / c
The electrolysis reaction was carried out for 40 seconds under m ² . afterwards,
The electrolytic reaction was stopped and the solar cell was washed with water.

Next, as in Example 2, the coating tank shown in FIG. 6 was used to apply a lipophilic curable resin coating material to the solar cell, which was an unsaturated polyester resin coating material. . The coating film was adjusted in viscosity and coating speed so that the thickness was about 1 μm.

Next, the solar cell coated with the unsaturated polyester resin coating is fixed horizontally with the coating surface facing upward,
A polyvinyl acetate-based hydrophilic conductive silver paste was applied from above the application surface. The paste has a viscosity of about 800c
ps, leave at room temperature for 30 minutes after application, then 120 ° C
Heated for 60 minutes.

For the solar cell of this example, the IV characteristics during light irradiation were measured in the same manner as in Example 2 above. The IV characteristics before and after the short-circuit removal processing are as shown in FIGS. 11A and 11B, respectively, and it can be seen that the dark current and the light (irradiation) current increase after the processing.

[0039]

As described above, according to the present invention, it is possible to easily and surely remove a short-circuited part including a large number of short-circuited parts, which improves the production efficiency of solar cells and reduces the manufacturing cost. I can contribute. Further, since the removal process and equipment can be simplified, the manufacturing cost can be reduced and the yield can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of an electrolytic cell for carrying out the method of the present invention.

FIG. 2 is a schematic cross-sectional view of a solar cell having a short circuit portion.

FIG. 3 is a schematic cross-sectional view after the transparent conductive oxide and the semiconductor layer in the short circuit portion are removed.

FIG. 4 is a schematic cross-sectional view after a lipophilic curable resin has been applied.

FIG. 5 is a schematic cross-sectional view after a hydrophilic conductive paint is applied.

FIG. 6 is a cross-sectional view showing a configuration example of a coating tank.

FIG. 7 is a schematic cross-sectional view of a solar cell according to a second embodiment.

FIG. 8 is a schematic sectional view of a solar cell according to a third embodiment.

FIG. 9 is a circuit diagram of a measurement system for measuring current-voltage characteristics of a solar cell.

FIG. 10 is a graph showing current-voltage characteristics before and after the treatment of the solar cell according to the second embodiment.

FIG. 11 is a graph showing current-voltage characteristics before and after the treatment of the solar cell according to the third embodiment.

[Explanation of Codes] 100, 200, 300, 400, 500, 700, 8
00 solar cell (photoelectric conversion device), 101, 201, 301 conductive substrate, 102, 202, 302, 402 semiconductor layer, 103, 203, 303, 403, 503 transparent conductive oxide layer, 204 current short-circuit portion, 703 803 shunt prevention layer 601 paint container, 404 lipophilic curable resin coating film, 505 hydrophilic conductive paint.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Fig. 2]

[Figure 3]

[Figure 1]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

[Figure 9]

[Figure 10]

FIG. 11

Claims (5)

[Claims] 1. A semiconductor layer and a transparent conductive oxide film forming a photoelectric conversion element are sequentially formed on a conductive substrate, and a short circuit portion is provided between the conductive substrate and the transparent conductive oxide film. In the method for removing a short circuit portion of a photoelectric conversion device, the photoelectric conversion element is immersed in an electrolyte solution in which a standard electrode potential, which is a redox potential of negative ions contained, is 0 or positive, and the conductive substrate is used as an anode. A step of removing the short-circuited portion by electrolytic oxidation using the counter electrode as a cathode, a step of applying a lipophilic curable resin coating material on the transparent conductive oxide film, and a hydrophilic property on the coating film of the curable resin coating material. A photoelectric conversion device comprising: a step of applying a conductive coating material to form a collector electrode; a step of curing the lipophilic curable resin coating material; and a step of drying the hydrophilic conductive coating material. Equipment damage Removal method. 2. The method for repairing a short-circuited portion of a photoelectric conversion device according to claim 1, wherein the negative ion contained in the electrolytic solution is a halogen ion or an ion containing a halogen. 3. The method for removing a short-circuited portion of a photoelectric conversion device according to claim 1, wherein the lipophilic curable resin is a thermosetting resin. 4. The hydrophilic conductive paint is a crosslinkable resin,
A conductive particle and an emulsifying agent are included, and it is characterized by the above-mentioned.
4. The method for removing a short-circuited portion of a photoelectric conversion device according to any one of claims 1 to 3. 5. In the electrolytic oxidation, the current density of the anode is 0.1 to 5.0 μA / cm ² , and the electrolysis time is 1 to 300 s.
ec, the temperature of the electrolytic solution is in the range of -5 to + 95 ° C.