JP3209702B2 - Photovoltaic device manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous silicon such as a solar cell in which a surface electrode is formed of a transparent electrode film made of a metal oxide or the like, and a metal collecting electrode is formed on the film.
Relates to photovoltaic instrumentation 置製 granulation how having a semiconductor portion of the emissions, regarding details improving the adhesion between the collector electrode and the surface electrode.

[0002]

2. Description of the Related Art Conventionally, in a photovoltaic device such as a solar cell or an optical sensor in which a transparent conductive film (TCO) made of a metal oxide or the like is used for a surface electrode, the surface electrode is reduced in order to reduce its in-plane resistance. It is necessary to form a collecting electrode made of a metal on the film.

If the photovoltaic device is easily damaged by heat, a vacuum deposition method, a method using a silver paste that can be sintered at a low temperature, a low-temperature melting type solder is used to prevent the device from becoming hot. Dipping method or JP-A-6-13255
A collector electrode is formed on a surface electrode film by, for example, a method of bonding a metal wire with a conductive adhesive described in Japanese Patent Publication No. 1 (H01L 31/04).

[0004] In the extreme case, the above-mentioned damage due to heat causes the semiconductor portion between the front electrode and the rear electrode to be microcrystallized or the like due to heating, and thermally deteriorates. Is increased, a short circuit between the front electrode and the back electrode (short between electrodes) appears.

[0005]

In the case where the metal of the collecting electrode is formed on the surface electrode film by vapor deposition, low-temperature sintering, soldering, bonding or the like so as not to be damaged by heat. In addition, there is a problem that adhesion between the collector electrode and the surface electrode is poor and the reliability of the device is reduced.

For example, when a collector electrode is formed by using a silver paste sintered at a low temperature or by a low-temperature melting type solder dipping method, if the collector electrode is left at room temperature for several days, peeling of the collector electrode occurs. This leads to a significant decrease in the reliability of the device.

[0007] When a vacuum deposition method or a bonding method of a metal wire with a conductive adhesive is employed, disadvantages such as the necessity of a large-scale vacuum process and a remarkable increase in material costs also occur.

According to the present invention, a short circuit between electrodes due to heat is prevented.
And to provide a photovoltaic device manufacturing how you to improve the adhesion between the collector electrode and the surface electrode.

[0009]

In order to solve the above-mentioned problems, in the method of manufacturing a photovoltaic device according to the present invention, instead of heating the entire device, the collector electrode is heated, and the collector electrode and the portion immediately below the collector electrode are heated. The light-transmitting surface electrode is locally heated and mixed with each other, and the collector electrode and the surface electrode are brought into close contact with each other.

[0010] In this case, the semiconductor portion immediately below the collector electrode is less thermally degraded, the short circuit between the front electrode and the back electrode is prevented, and the adhesion between the collector electrode and the front electrode is improved.

Therefore, even in the case where the photovoltaic device is easily damaged by heat, a highly reliable photovoltaic device can be obtained by sufficiently adhering the current collector and the surface electrode without a large vacuum process or a rise in material costs. Can be manufactured at low cost.

It is practical and preferable to heat the collecting electrode by induction heating by irradiating an electromagnetic wave or by irradiating a laser beam.

Further, in order to reliably prevent a short circuit between the front electrode and the back electrode due to heating of the collector electrode, an insulator is interposed between the front electrode and the back electrode substantially immediately below the collector electrode to form the collector electrode. It is desirable to heat.

In this case, the thermal deterioration of the semiconductor portion due to the heating of the collector electrode is improved by the insulator, and the short circuit between the front electrode and the back electrode is reliably prevented.

Then, the portion of the back electrode substantially immediately below the collector electrode may be removed, and the collector electrode may be heated in the same state as when the insulator is provided.

Further, when the semiconductor portion has a high conductivity layer, it is preferable to remove the portion of the high conductivity layer and the back electrode substantially immediately below the collector and heat the collector.

[0017]

[0018]

[0019]

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. (First Embodiment) First, an amorphous silicon solar cell (hereinafter, amorphous syringe is referred to as a-Si), which is an example of a photovoltaic device, is manufactured by removing a portion of the back electrode substantially immediately below the collector electrode. The case will be described with reference to FIGS.

FIG. 1 is a cross-sectional view showing the structure of an a-Si solar cell 1 having a single-cell sub-module structure. The sub-module of this solar cell 1 has a back electrode 3 made of metal and a semiconductor section 4 on a substrate 2. And a transparent electrode film (TCO) made of a metal oxide or the like, a surface electrode 5 is formed, a metal collecting electrode 6 is formed on the film of the surface electrode 5 in a predetermined electrode pattern, and the collecting electrode 6 is heated to collect the collecting electrode. 6 and the surface electrode 5 are adhered to each other.

At this time, in order to reliably prevent a short circuit between the front electrode 6 and the back electrode 3 due to heating of the collector electrode 6,
As shown in the back electrode pattern of FIGS. 1 and 2, the back electrode 3 is formed by removing a portion substantially immediately below the collector electrode and providing, for example, a stripe-shaped groove 3 ′ along the pattern of the collector electrode 6.

The width of the groove 3 ′ is slightly wider than the width of the collector electrode 6 in order to prevent a decrease in power conversion efficiency as much as possible and to reliably prevent a short circuit between the front electrode 5 and the back electrode 3. Is preferred.

Further, after the back surface electrode 3 is formed , the semiconductor portion 4 of the amorphous silicon having the PIN structure becomes n, n by a plasma reaction.
The i-layer is formed by sequentially generating three layers, i and p.
It is made of Si.

Further, the surface electrode 5 is formed by forming a transparent conductive film of ITO, ZnO ₂ or the like on the surface of the semiconductor portion 4 by sputtering or the like, and the collector electrode 6 on the film is formed by screen printing a silver paste, for example. Sintered at low temperature to form the collector electrode pattern of FIG. Incidentally, reference numeral 7 in FIG. 3 denotes a bus bar formed to extract a current from the collector electrode 6.

Next, the heating for improving the adhesion of the formed collector electrode 6 is performed by, for example, irradiating a high-frequency electromagnetic wave beam from above to each part thereof and generating an eddy current by high-frequency induction heating.

At this time, since the electromagnetic wave is intensively applied to the collector electrode 6 and the eddy current is more easily generated in the metal collector electrode 6 than in the surface electrode 5, only the collector electrode 6 is efficiently heated. By this heating, the contact portions of the collector electrode 6 and the surface electrode 5 with the collector electrode 6 are instantaneously melted at a high temperature and mixed with each other, so that the collector electrode 6 and the surface electrode 5 are firmly adhered to each other.

Then, only the collector electrode 6 is efficiently heated without heating the entire solar cell 1. Further, in the present embodiment, a groove 3 ′ is provided almost immediately below the collecting electrode 6, from which the back surface electrode 3 is removed and the insulating surface of the substrate 2 is exposed. Groove 3 '
Are formed on the insulating surface of the substrate 2. Therefore, even if a-Si is microcrystallized due to heating in the semiconductor portion 4 immediately below the collecting electrode 6 and the conductivity increases, the back electrode 3 and the front electrode 5 are short-circuited through this portion. I will not do it.

Therefore, when manufacturing the solar cell 1,
A short circuit between the front electrode 5 and the back electrode 3 due to heat can be prevented, the adhesion between the front electrode 5 and the collector electrode 6 can be greatly improved, and high reliability without peeling of the collector electrode 6 can be achieved. a-
Si solar cells can be obtained at low cost.

Incidentally, the electromagnetic wave beam used for heating the collector electrode 6 may be a microwave band beam.

Alternatively, heating may be performed by irradiating a laser beam with a pulse instead of irradiating the electromagnetic wave beam.

(Second Embodiment) Next, a case where an a-Si solar cell is manufactured by preventing electrode short-circuiting even more reliably than in the first embodiment will be described with reference to FIGS. I do. FIG. 4 is a sectional view similar to FIG.
The point that the a-Si solar cell 1 of FIG.
Not only in the n-layer (high-conductivity layer) in which the conductivity of the semiconductor portion 4 is high but also almost immediately below the collector electrode is removed.

Incidentally, the n-layer is processed by a method such as etching using a mask or irradiation of a laser beam to remove an unnecessary portion immediately below the collector electrode.

When the solar cell 1 is manufactured by removing only a portion of the back electrode 3 almost immediately below the collector electrode as shown in FIG. 1, the semiconductor portion 4 is heated by heating the collector electrode 6 as shown in FIG. The n-layer having high conductivity contacts the deteriorated portion 4 'almost immediately below the collector electrode, and a leak current as indicated by an arrow may occur.

However, as shown in FIG. 4, not only the back layer 3 but also the n-layer having a large conductivity of the semiconductor portion 4 is removed almost completely immediately below the collector electrode to manufacture the solar cell 1 as shown in FIG. As shown in the figure, the n-layer does not contact the deteriorated portion 4 ',
Leakage current can be completely eliminated.

[0036] That is, the solar cell 1 of the structure of Figure 4, the collector electrode 6 by heating the collector electrode 6 in the same manner as in FIG. 1
When improving the adhesion to the front electrode 5 , the short circuit between the front electrode 5 and the back electrode 3 can be prevented more reliably than the structure of FIG. An a-Si solar cell having improved adhesion to the film 5 and improved reliability can be obtained.

(Third Embodiment) Next, instead of removing the back electrode and part of the n-layer, an insulator is provided between the front electrode and the back electrode, ie, between the back electrode and the semiconductor portion. A case of manufacturing an a-Si solar cell will be described with reference to FIGS.

FIG. 7 is a sectional view similar to FIGS. 1 and 4,
The difference between the solar cell 1 of FIG. 7 and FIGS. , S
It is formed by providing an insulator 8 such as iO ₂ or SiN.

Prior to the formation of the semiconductor portion 4, the insulator 8 is formed and provided almost immediately below the collector electrode on the surface of the back electrode 3, for example, as shown in an insulator application pattern in FIG.

After the formation of the semiconductor portion 4, the collector electrode 6 is formed by the collector electrode pattern of FIG. 9 similar to FIG.

Then, the collector electrode 6 is heated by the above-described high frequency electromagnetic induction or laser beam irradiation, and the solar cell 1 is manufactured.

In this case, the insulator 8 is located between the front surface electrode 5 and the back surface electrode 3, that is, in the semiconductor portion 4, at a deteriorated portion similar to the deteriorated portion 4 ′ in FIGS. Equivalently, the resistance of the deteriorated portion increases and the leak current passing through the portion decreases, and the same effects can be obtained without removing the back electrode 3 and the n-layer as shown in FIGS.

Therefore, also in the case of this embodiment, the adhesion between the collector electrode 6 and the surface electrode 5 is improved, and the reliability is improved.
An Si solar cell can be obtained.

In some cases, the removal of a part of the back electrode 3 or the removal of a part of the high conductivity layer of the back electrode 3 and the semiconductor portion 4 and the formation of the insulator 8 may be used together.

(Fourth Embodiment) Next, a hybrid solar cell in which a crystalline solar cell and an amorphous solar cell are combined by artificial construction bonding (so-called HIT (Heteroju
The case where the present invention is applied to the manufacture of an nction with intrinsic thin-layer (structured solar cell) will be described with reference to FIGS.

FIG. 10 shows this HIT structure solar cell 9 shown in FIG.
1 shows a structure in which the collector electrode 10 is omitted. In the figure, 11 is a surface electrode (TCO), 12 is a semiconductor portion, and p-type
Layer, i-layer and n-type crystalline silicon (n-Si) layer, a-S
An i-type highly doped (n ⁺ ) diffusion layer. 13 is a back surface electrode.

The solar cell 9 is manufactured by forming p, i, and n ⁺ layers of a-Si on a n-Si substrate by a plasma reaction, and then forming the front surface electrode 11 and the back surface electrode 13 by a vapor deposition method or the like. It is formed and performed.

Further, the collector electrode 10 having the same electrode pattern as that shown in FIGS.
The collector electrode 10 is formed by sintering, and is connected to the bus bar 14.

Then, the formed collector electrode 10 corresponds to the first
As in the third to third embodiments, heating is performed by high-frequency electromagnetic induction heating or laser light irradiation.

In this case, the back electrode 13 and the high-conductivity layer of the semiconductor portion 12 are not removed or an insulator is not formed, but the collector electrode 10 is heated intensively and the front electrode 11 and the collector electrode 10 are not heated.
DOO order to contact, damage of the solar cell 9 according to the heating,
That is, the electrode short-circuit between the front electrode 11 and the back electrode 13 is prevented, and the adhesion between the collector electrode 10 and the front electrode 11 is improved.

[0051] Then, the present invention can be applied to the manufacture of photovoltaic devices of various semiconductor structures A Amorphous system, in which the semiconductor portion may be a multilayer integrated structure of a tandem type, etc. Of course, the surface electrode may have a pyramid-shaped texture structure or the like.

The process for forming the electrodes and the semiconductor may be any process, omitting the process of heating the collector electrodes 6 and 10.

[0053]

Next, a method of manufacturing a photovoltaic device according to the present invention and a photovoltaic device obtained by the method will be specifically described. Example 1 First, an example of the first embodiment will be described with reference to FIG.
This will be described with reference to FIGS. The solar cell 1 of FIG.
, The substrate 2 of the sub-module is 12 cm square (120
mm × 120 mm).

The back electrode 3 was formed by depositing Ag in a range of 100 mm × 110 mm (about 76%) shown in FIG.

Further, the groove 3 ′ is formed by bringing a mask into close contact with the substrate 2 when depositing the back electrode 3.
The width is 1mm (10% of the pattern interval (10mm))
And

Next, a 10 cm square (100 mm × 100 mm) semiconductor portion 4 and a front surface electrode 5 were sequentially formed on the substrate 2 on which the back surface electrode 3 was formed.

At this time, the semiconductor portion 4 was formed by RF-CVD, and the surface electrode 5 was formed of ITO by RF-magnetron sputtering.

The forming conditions at that time are as shown in Tables 1 and 2 below, and the thickness of the semiconductor portion 4 is 5000 °
Hereinafter, the thickness of the surface electrode 5 is set to 1000 ° or less.

[0059]

[Table 1]

[0060]

[Table 2]

Next, a silver paste having a width of 0.5 mm (50% of the width of the groove 3 ') and a thickness of 0.5 mm is formed on the film of the surface electrode 5 as a collector electrode 6 by screen printing into the pattern shown in FIG. Applied.

The silver paste was fired in a thermostat at 150 ° C. for 1 hour to form a collector electrode 6.

After that, the collector electrode 6 is formed by a high-frequency induction heating method.
Only heated intensively. The conditions for this heating process are:
200 Wh / kg, 400 kHz, 30 seconds.

When the temperature during this heating was measured with a thermoviewer, the temperature of the collector electrode 6 reached about 550 ° C.
The temperature of the other surface electrodes 5 was about 100 ° C.

The electromagnetic wave used for the induction heating is
The irradiation of the electromagnetic wave beam was regulated by a stainless steel mask body having an opening of an appropriate size so that the irradiation was performed only on the substrate.

On the other hand, in order to examine the conversion efficiency of the manufactured solar cell 1, as a solar cell to be compared, the back electrode, the semiconductor portion, and the front electrode were formed under the same conditions as the solar cell 1 without providing a groove in the back electrode. Was formed, and a solar cell (comparative sub-module) having a sub-module configuration in which a collector electrode having the same shape as the collector electrode 6 was formed on the surface electrode by vapor deposition of silver was manufactured.

When the solar cell 1 is an example sub-module, the output characteristics of this sub-module and the comparison sub-module are as shown in Table 3 below.

[0068]

[Table 3]

From Table 3, it can be seen that the characteristics of the solar cell 1 manufactured in this embodiment are not deteriorated by the induction heating treatment of the collector electrode 6, that is, the insulation between the front electrode 5 and the back electrode 3 is maintained. It turned out to be dripping.

When the collector electrode 6 of the solar cell 1 was not subjected to high-frequency induction heating, the initial characteristics and the output characteristics after being left for one week in a room were measured, and the results are shown in Table 4 below. Was.

[0071]

[Table 4]

As is apparent from Table 4, when the collector electrode 6 was not heated, the initial characteristics were the same as those after the high-frequency induction heating process, but the characteristics after standing for one week were mainly due to the shape factor. F. F. Has dropped significantly.

This is considered to be the result of an increase in contact resistance between the surface electrode and the collector electrode.

On the other hand, according to the invention of the present application, it was confirmed that the surface electrode 5 and the collector electrode 6 were in close contact with each other by heating the collector electrode 6 in the solar cell 1.

The adhesion between the surface electrode 5 and the collector electrode 6 depends on the heating temperature of the collector electrode 6, and the induction heating temperature of the silver paste is improved from about 200 ° C. or more. The improvement is described in F. F. It was confirmed from the fact that the deterioration with time decreased and the reliability improved.

Specifically, after leaving the room for one week at the heating temperature of the collector electrode 6, F. Showed the characteristics shown in FIG.

The above-mentioned adhesion is determined by changing the conditions of the heating process of the collector electrode 6 from 50 Wh / kg to 1500 Wh / kg,
It was confirmed that the improvement was achieved even in the range of 0 kHz to 10 MHz and 1 to 60 seconds.

By the way, if the width of the groove 3 ′ of the back electrode 3 is 0.7 mm or more (1.4 times or more of 0.5 mm of the width of the collector electrode 6), the width of the surface electrode during induction heating is increased. It has been found that a short circuit between the electrode 5 and the back electrode 3 does not occur.

However, as the width increases,
Because the effective area as a solar cell module decreases,
It is considered that the width of the groove 3 'is desirably 1 mm or less.

Next, when the collector electrode 6 was heated by irradiating a laser beam, the characteristics shown in the following Table 5 were obtained as the output characteristics.

[0081]

[Table 5]

The output characteristics in Table 5 are obtained when the collector electrode 6 is heated by irradiating a laser beam instead of the above-described high-frequency induction heating. Other manufacturing conditions are the same as those in the above-described high-frequency induction heating. It is. The laser used was a CW-YAG laser, and the irradiation condition was 20 mW / cm ^2.
And

Then, the collector electrode 6 was heated by irradiating a laser beam under the above-mentioned irradiation conditions. As a result, the collector electrode 6 was heated to about 400 ° C.

Table 5 shows the initial efficiency of the output of the solar cell 1 and the result of measurement after being left in the room for one week. As is clear from the result, even when heating was performed by irradiating laser light, It has been found that the adhesion between the electrode 6 and the surface electrode 5 is improved, and the reliability is improved.

(Embodiment 2) Next, an embodiment of the second embodiment will be described with reference to FIGS. In this embodiment, a mask for depositing the back electrode 3 is used in the first embodiment.
The width of the groove 3 'in FIG. 4 was reduced to 0.5 mm (the same as the width of the collector electrode 6 of 0.5 mm).

For removing the n-layer, a pulse YAG laser (wavelength: 1.06 μm) having a wavelength of 1.06 μm is used.
The laser intensity was 1 × 10 ⁶ J / pulse. In addition,
Other conditions were the same as in Example 1.

Then, only the back electrode 3 of FIG.
And the back electrode 3 and n in FIG.
The output characteristics of the solar cell 1 from which the layer was removed were as shown in Table 6 below.

[0088]

[Table 6]

As is clear from Table 6, the characteristics of the solar cell 1 of FIG. 4 are superior to those of FIG.

This is because, in the solar cell 1 shown in FIG. 1, since the deteriorated portion 4 ′ shown in FIG.
This is because a leak current flows between the front surface electrode 5 and the back surface electrode 3, but no leak current flows in the case of the solar cell 1 of FIG. 4 as shown in FIG.

In the case of the solar cell 1 of FIG. 4 as well, if the width of the groove 3 ′ of the back electrode 3 is set to 0.7 mm or more (1.4 times or more the width of the collecting electrode 6), And heat-degraded a-
It is considered that the distance between Si is widened and the adverse effect on the solar cell characteristics is further reduced.

[0092] Also in the solar cell 1 of the present example, it was found that the adhesion between the collector electrode 6 and the surface electrode 5 was improved, and the reliability was improved.

(Embodiment 3) Next, an embodiment of the third embodiment will be described with reference to FIGS. In this embodiment, the substrate 2 of FIG. 7 is a glass substrate of 12 cm square, and a back electrode 3 and an insulator 8 are formed on the substrate 2 as shown in FIG. , Collector electrode 6
Was formed.

The insulator 8 was formed by applying a glass paste by screen printing and sintering to a thickness of about 3000 °. The sintering process was performed at 350 ° C. for about one hour in a nitrogen atmosphere.

Also, the semiconductor part 4, the surface electrode 5, the collecting electrode 6
The same high-frequency induction heating process as in Example 1 was applied to the heating of the collector electrode 6.

On the other hand, in order to measure the conversion efficiency of the solar cell 1 of FIG. 7, a back electrode, a semiconductor portion, and a front electrode are formed in the same manner as the solar cell 1 of FIG. A solar cell (comparative sub-module) in which collector electrodes having the same electrode pattern were formed by silver deposition was manufactured.

Then, assuming that the solar cell 1 of FIG. 7 is an example sub-module, the output characteristics of this sub-module and the comparison sub-module are as shown in Table 7 below.

[0098]

[Table 7]

As is clear from Table 7, even in the solar cell 1 of this embodiment, the characteristics are not deteriorated by the induction heating treatment of the collector electrode 6, and the characteristics between the front surface electrode 5 and the back surface electrode 3 are not deteriorated. It was found that the insulation was maintained, the adhesion between the collector electrode 6 and the surface electrode 5 was improved, and the reliability was improved.

The insulator 8 between the back electrode 3 and the semiconductor portion 4 is 0.6 mm (1 mm of the collector electrode 6 having a width of 5 mm).
It was found that if the width was twice or more, no short circuit between the front electrode 5 and the back electrode 3 occurred during the induction heating.

However, since the effective area of the solar cell module decreases as the width increases, it is considered preferable to set the width to 1 mm (twice the width of the collector electrode 6) or less.

Example 4 Next, an example of the fourth embodiment will be described with reference to FIG. In this example, the present invention was applied to the manufacture of the HIT solar cell 9 shown in FIG. Regarding the solar cell 9, first, each layer of a-Si of the semiconductor unit 12 is RF-CV
The surface electrode 11 was formed by an RF-magnetron sputtering method.

These forming conditions were set as shown in Tables 8 and 9 below.

[0104]

[Table 8]

[0105]

[Table 9]

Further, after forming an ITO film as the surface electrode 11, a silver paste is applied to the collector electrode pattern of FIG. 11 on the film and sintered to form a collector electrode 10. Was heated by a high frequency induction heating method.

The heating conditions were the same as in Example 1. Then, after heating the collector electrode 10, the back electrode 13 was formed by vapor deposition of silver.

On the other hand, in order to examine the characteristics of the solar cell 9,
A solar cell (comparative sub-module) having a HIT structure having the same surface electrode, rear electrode, and semiconductor portion as the solar cell 9 was formed.

On the surface electrode film of this comparative submodule, a collector electrode was formed by depositing silver using the collector electrode pattern shown in FIG. 11, and this collector electrode was not heated like the collector electrode 10. Was.

The initial output characteristics of the solar cell 9 (Example sub-module) and the comparison sub-module are as shown in Table 10 below.

[0111]

[Table 10]

As is clear from Table 10, the characteristics of the solar cell 9 were not deteriorated by the heating of the collector electrode 10, and the insulation between the front electrode 11 and the back electrode 13 was maintained.

When the collector was formed only by applying and sintering a silver paste and the high-frequency induction heating process was not performed on the collector, the initial characteristics and the characteristics after being left in a room for one week are as follows. The results are as shown in Table 11.

[0114]

[Table 11]

As is clear from Table 11, when the collector was not heated (high-frequency induction heating), the initial characteristics were the same as those when the collector was subjected to the high-frequency induction heating process. F. F. Has dropped significantly.

This is considered to be the result of poor adhesion between the collector electrode and the surface electrode, and an increase in contact resistance between the two electrodes.

That is, from Table 11, it was confirmed that the effect of improving the adhesion between the surface electrode 11 and the collector 10 by heating the collector 10 of the solar cell 9 was confirmed.

[0118]

The present invention has the following effects. First, in the photovoltaic device manufacturing method of the present invention,
Instead of heating the entire apparatus , the collector electrodes 6, 10 and the surface electrodes 5, 11 immediately below the collector electrodes are locally heated and mixed with each other, and the collector electrodes 6, 10 and the surface electrodes 5 , 11 are brought into close contact with each other. Therefore, thermal degradation of the semiconductor portion 4, 12 between the front surface electrode 5 and 11 and the back electrode 3 and 13 is extremely small, to prevent short circuit between electrodes of the surface electrode 5 and 11 and the back electrode 3, 13
Semiconductor portions 4 and 12 made of amorphous silicon.
The collector electrodes 6 and 10 and the surface
Adhesion with poles 5 and 11 can be improved.

Therefore, even when the collector electrodes 6 and 1 are easily damaged by heat without increasing the vacuum process or material cost.
Thus , a highly reliable photovoltaic device can be manufactured at low cost by bringing the 0 and the surface electrodes 5 and 11 into close contact with each other.

The heating of the collecting electrodes 6 and 10 is performed by induction heating by electromagnetic wave irradiation or laser light irradiation.
The poles 5 and 11 can be brought into close contact.

The surface electrodes 5, 11 almost immediately below the collector electrode
By heating the collector electrodes 6 and 10 with the insulator 8 interposed between the back electrodes 3 and 13, a short circuit between the front electrodes 5 and 11 and the back electrodes 3 and 13 is more reliably prevented. Reliability can be further improved.

Further, by removing the portion of the back electrodes 3 and 13 immediately below the collector electrode and heating the collector electrodes 6 and 10, the case where the insulator 8 is provided without the insulator 8 is provided. An equivalent effect can be obtained.

If the semiconductor portions 4 and 12 have a high conductivity layer, the portions of the high conductivity layer and the back electrodes 3 and 13 which are almost immediately below the collector electrodes are removed to heat the collector electrodes 6 and 10. By doing so, it is possible to prevent a short circuit between the front electrodes 5 and 11 and the back electrodes 3 and 13.

[0124]

[0125]

[Brief description of the drawings]

FIG. 1 is a sectional view of a solar cell according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a back electrode pattern of FIG. 1;

FIG. 3 is a plan view showing a collector electrode pattern of FIG. 1;

FIG. 4 is a sectional view of a solar cell according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view for explaining a leak current accompanying thermal degradation when the n-layer of the solar cell of FIG. 4 is not removed.

6 is a cross-sectional view for explaining a leak current caused by thermal deterioration of the solar cell of FIG.

FIG. 7 is a sectional view of a solar cell according to a third embodiment of the present invention.

FIG. 8 is a plan view showing an insulator application pattern of FIG. 7;

FIG. 9 is a plan view showing the collector electrode pattern of FIG. 7;

FIG. 10 is a sectional view of a solar cell according to a fourth embodiment of the present invention in a state where a collector electrode is removed.

FIG. 11 is a plan view showing a collector electrode pattern formed in the solar cell of FIG.

FIG. 12 is a characteristic diagram of a solar cell with respect to a collecting electrode heating temperature in Example 1 of the present invention.

[Explanation of symbols]

 1,9 solar cell 2 substrate 3,13 back electrode 4,12 semiconductor part 5,11 front electrode 6,10 collector electrode 8 insulator

Continuation of the front page (56) References JP-A-7-99331 (JP, A) JP-A-62-213282 (JP, A) JP-A-64-41277 (JP, A) JP-A-7-321353 (JP) JP-A-6-151915 (JP, A) JP-A-7-335921 (JP, A) JP-A-61-57544 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB (Name) H01L 31/04-31/078

Claims (6)

(57) [Claims] 1. Transparent surface electrode / from amorphous silicon
Becomes formed in the layer structure of the semiconductor unit / back electrode, wherein the photovoltaic device manufacturing method of manufacturing a photovoltaic device in which the metal of the collector electrode is formed on the film of the surface electrode, the collector electrode and immediately below the Local heating of the surface electrode
And causing the collector electrode and the surface electrode to adhere to each other by mixing with each other . 2. The method for manufacturing a photovoltaic device according to claim 1, wherein the heating of the collector electrode is performed by induction heating by irradiation of electromagnetic waves. 3. The method according to claim 1, wherein the collector electrode is heated by irradiating a laser beam. 4. The photovoltaic device according to claim 1, wherein an insulator is interposed between the front electrode and the back electrode substantially immediately below the collector electrode, and the collector electrode is heated. Power device manufacturing method. 5. The method for manufacturing a photovoltaic device according to claim 1, wherein a portion of the back electrode substantially immediately below the collector is removed, and the collector is heated. 6. The collector according to claim 1, wherein a portion of the high conductivity layer on the back electrode side constituting the semiconductor portion and a portion of the back electrode substantially immediately below the collector are removed, and the collector is heated. The method for manufacturing a photovoltaic device according to claim 3.