JPH0974212A - Photovoltaic element array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the conduction between the adjacent unit elements, and to lessen the loss of output power between the first electrode and the second electrode by a method wherein an insulating member is composed of two layers of the first insulating layer with high thermal conductivity and the second insulating layer with low thermal conductivity. SOLUTION: An insulating member, i.e., an insulating layer 602, consists of the two layers of the first high thermal conductivity insulating layer 102a and the second low thermal conductivity insulating layer 102b. As the first electrode 103 comes in contact with the low thermal conductivity insulating layer 102b, thermal loss is small when the first electrode 103 and the semiconductor photovoltaic layer 105 are processed, and a processing operation can be finished in a short period of time. As the heat transmitted to the insulative layer 102a can be dispersed to a metal substrate easily, the accumulation of heat is small and the insulating layer 102a is hardly damaged. As a result, the insulating layer 102b is damaged when a laser beam is excessively strong, and in an extreme case, the insulating film 102a can be left even when the insulating layer 102b is entirely removed, and no influence is given to the function as an insulating layer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photovoltaic device array. More specifically, the present invention relates to a photovoltaic element array that has high performance, high reliability, and functions as a solar cell that can be easily mass-produced.

[0002]

2. Description of the Related Art As a future energy source for humanity,
Due to carbon dioxide generated as a result of its use, oil and coal, which are said to bring global warming, and an unexpected accident,
Furthermore, there are many problems in relying entirely on nuclear power, which can be said to have no danger of radiation even during normal operation. Since solar cells use the sun as an energy source and have very few shadows for the global environment, they are expected to become even more widespread. However, in the present situation, the following problems can be cited as problems that prevent full-scale dissemination.

Conventionally, monocrystalline or polycrystalline silicon has been widely used for solar power generation. However, in these solar cells, a lot of energy and time are required for crystal growth, and a complicated process is required thereafter, so that the mass production effect is difficult to increase and it is difficult to provide at a low price. there were.

In order to solve this problem A, amorphous silicon (hereinafter referred to as a-Si) or CdS.Cu
So-called thin-film semiconductor solar cells using compound semiconductors such as InSe ₂ have been actively researched and developed. For these solar cells, inexpensive substrates such as glass, stainless steel, and aluminum can be used, and it suffices to form as many semiconductor layers as are functionally necessary on these substrates,
Since the manufacturing process is relatively simple and the amount of semiconductors used is small, it is advantageous in that it can be manufactured at a lower price.

However, since the above-mentioned solar cell generally has a low output voltage in a single element, there is a problem B that the output voltage needs to be increased by connecting the single elements in series for most applications. .

In order to solve the problem B, it is necessary to form an array of elements connected in series on the same substrate in the thin film semiconductor solar cell. As the solution, for example, the following three patents are listed. (A) US Pat. No. 4,254,386 (filing date: 19
(June 13, 1979), a plurality of divided first electrodes on an insulating substrate, a divided thin film semiconductor photovoltaic layer (pn junction), and a divided second electrode. The structure of a series connected photovoltaic device array is disclosed.

(B) US Pat. No. 4,292,092 (filing date: September 29, 1981) discloses a method of using a laser beam as a means for dividing a conductive layer or a semiconductor photovoltaic layer. It is disclosed. (C) US Pat. No. 4,697,041 (filing date: 19
(February 10, 1986), a method of using a laser beam as a means for electrically connecting the first electrode and the second electrode is disclosed.

[0008] According to these methods, it is pointed out that the series-connected photovoltaic element array can be produced at a low cost because the division / serial connection of each layer can be easily performed. However, in the above patents (A) to (C), the substrate to be used is limited to the insulating film, and there is a problem C that there is no degree of freedom in selecting the substrate.

When a thin film semiconductor is used, US Pat. No. 4,369,730 (filing date: March 16, 1981)
Using the flexible long substrate disclosed in
Since it can be used while being rolled up, it is suitable for continuous mass production of solar cells.

In principle, an insulating resin film can be used as the substrate in this case, but it is necessary to heat the substrate to at least 200 ° C. or higher in order to manufacture a thin film semiconductor having good characteristics. Therefore, there is a problem D that a normal resin film is difficult to use because it melts or deforms due to heat and releases gas. On the other hand, a film having excellent heat resistance, such as polyimide, has a problem E that the cost is high because it is difficult to process into a film.

In order to solve the problems D and E, a thin plate made of metal such as stainless steel or aluminum has been put to practical use as a flexible long substrate.

However, since the metal substrate itself is electrically conductive, it was necessary to lay an insulating layer on this surface before forming the series-connected photovoltaic element array. As a solution to this problem, for example, in U.S. Pat. No. 4,410,558 (filing date: March 16, 1981), an anodized layer is formed on a substrate made of aluminum, and then a series connection photovoltaic is formed. Techniques for making power element arrays are disclosed.

By the way, in the series-connected photovoltaic element array, a high output voltage of 12 V or 24 V can be obtained. Therefore, the insular layer laid on the metal substrate is
It is required to withstand a potential difference generated between the electrode layer and the metal substrate. If the withstand voltage of the insulating layer is insufficient, not only the generated electric power is lost but also there is a risk of leakage, so the material and thickness of the insulating layer must be designed optimally.

Further, when the laser scribing method is used for dividing the metal layer or for making electrical connection between the electrodes, there is a possibility of damaging the insulating layer directly below the processed portion. Therefore, conventionally, it has been considered difficult in reality, if not impossible, to manufacture a series-connected photovoltaic element array by laser processing using a metal substrate.

The problems that occur in the series-connected photovoltaic element array manufactured using the above-mentioned conventional laser beam will be described below. (1) Problems relating to "conduction between adjacent unit elements due to incomplete division of the first electrode". When metal is used as the substrate, heat easily diffuses to the substrate,
When the first electrode is melted and vaporized by irradiation with a laser beam to perform division, the temperature does not rise sufficiently, and the division of the first electrode is likely to be incomplete. If the division of the first electrode is incomplete, the electric power generated by the unit element will be lost.

(2) A problem concerning "output power loss due to series resistance between the first electrode and the second electrode". When the connection between the first electrode and the second electrode is made by changing the resistance of the photovoltaic layer by irradiating the laser beam to lower the resistance, a portion with high resistance remains if the intensity of the laser beam is insufficient. Series resistance loss occurs when current flows.

(3) Problems related to "damage of insulating layer due to laser beam irradiation". On the other hand, in the steps (1) and (2), even if the intensity of the laser beam is sufficient and the first electrode is completely divided or the electrodes are completely connected, the insulating layer is formed during this process. Due to the heat transmitted to the insulating layer, the insulating layer is also melted and vaporized to make the surface extremely rough, the surface of the metal substrate is exposed, and the insulating layer is likely to be cracked due to thermal expansion. In such a state, there is conduction between the first electrode and the metal substrate, or the deposition of the photovoltaic layer on this is disturbed, and there is conduction between the first electrode and the second electrode.

As described above, there are many difficulties in determining the optimum value of the laser beam intensity. Depending on the case, any one of the above problems, or 2
One or more things happened and I couldn't decide the proper value.

[0019]

SUMMARY OF THE INVENTION The present invention improves the insulating member and / or the first electrode to reduce the conduction between adjacent unit elements and reduce the output power loss between the first electrode and the second electrode. It is an object of the present invention to provide a photovoltaic element array that functions as a highly efficient, low-cost, highly reliable solar cell by reducing the size and reducing damage to the insulating layer due to the laser beam.

[0020]

A photovoltaic element array according to the present invention is provided on an insulating member, and is provided on a plurality of first electrodes electrically divided by grooves and on the first electrodes. A position which is provided on the photovoltaic layer made of a semiconductor and the photovoltaic layer, is displaced from the groove of the first electrode by a distance X in the plane direction, and is parallel to the groove of the first electrode. A plurality of second electrodes electrically divided by a groove, and an electric contact portion between the first electrode and the second electrode within the range of the distance X in the photovoltaic layer. In the photovoltaic element array, the insulating member includes a first insulating layer having a high thermal conductivity and a second insulating layer having a low thermal conductivity provided on the first insulating layer. It is characterized by

The thermal conductivity of the first insulating layer is 0.0.
5 cal / (cm · sec · deg) or more, and the thermal conductivity of the second insulating layer is 0.05 cal / (cm · se).
It is preferably less than c · deg).

Further, the first electrode has a wavelength of 0.7 μm.
Reflectance of 85% or more, and wavelength 0.53
It is preferably made of a metal having a reflectance of 70% or less for μm light.

In particular, as the metal forming the first electrode, copper or an alloy containing 70 atomic% or more of copper is preferable.

Furthermore, the insulating member may be provided on the conductive substrate.

[0025]

FIG. 1 is a sectional view showing an example of the photovoltaic element array of the present invention. In FIG. 1, 101 is a conductive substrate, 102 a is a first insulating layer having a high thermal conductivity, 102 b is a second insulating layer having a low thermal conductivity, 103 is a first electrode, and 104.
Is a groove separating the first electrode, 105 is a photovoltaic layer made of a semiconductor, 106 is an electrical connection portion, 107 is a second electrode, 1
Reference numeral 08 is a groove for separating the second electrode.

The operation according to claim 1 of the present invention will be described below with reference to FIG. In the first aspect, the insulating member, that is, the insulating layer 602 (FIG. 6), which has a single structure in the past, has two layers 102a and 102b as shown in FIG. In particular, the lower layer 102a was the first insulating layer having a high thermal conductivity, and the upper layer 102b was the second insulating layer having a low thermal conductivity.

As a result, the following three actions are obtained. Since the insulating layer 102b in contact with the first electrode 103 has a low thermal conductivity, there is little heat loss when the first electrode 103 and the semiconductor photovoltaic layer 105 are processed by a laser beam, and light that can complete the processing in a short time. An electromotive force element array is obtained.

The above means that heat is easily accumulated in the insulating layer 102b itself, and in particular, the surface thereof is easily damaged by heat to some extent. However, since the insulating layer 102a has high thermal conductivity and easily releases the transferred heat to the metal substrate, the insulating layer 102a hardly accumulates heat and is not easily damaged. As a result, if the laser beam intensity is excessive, the insulating layer 102b may be damaged or, in an extreme case, all may be removed, but the insulating film 102a can remain, so that the function as an insulating layer is not achieved. A photovoltaic element array having no influence can be obtained.

Furthermore, since the insulating layer is formed into two layers, heat loss is small, so that the first layer can be formed with a relatively low laser beam intensity.
The electrode 103 and the photovoltaic layer 105 made of a semiconductor can be processed. Therefore, it is possible to obtain the photovoltaic element array capable of expanding the latitude of the processing conditions by the laser beam.

In the second aspect, the thermal conductivity of the first insulating layer is 0.05 cal / (cm · sec · deg) or more, and the thermal conductivity of the second insulating layer is 0.05 cal / (cm · s).
Since it is less than ec · deg), the latitude of the processing conditions by the laser beam can be particularly widened. As a result, a photovoltaic element array with stable characteristics and high reliability can be obtained.

In the third aspect, the first electrode 103 is made of a metal having a reflectance of 85% or more for light having a wavelength of 0.7 μm and a reflectance of 70% or less for light having a wavelength of 0.53 μm. Therefore, it is possible to obtain a photovoltaic element array in which the transmitted light loss of the photovoltaic layer made of a semiconductor in the vicinity of the wavelength of 0.7 μm is improved.

For such processing, Nd-YA is usually used.
A G-laser (fundamental wave = 1.06 μm) is used, but a photovoltaic device array in which a second harmonic wave having a wavelength of 0.53 μm can also be used is obtained.

Further, most of the light having a wavelength of about 0.5 μm is almost absorbed by the photovoltaic layer 105 made of a semiconductor, so that the first electrode 103 has a high reflectance at wavelengths around this. No need. On the contrary, if the reflectance with respect to the light of such a wavelength is low (that is, the absorption is large), the absorption of the second harmonic of the Nd-YAG laser increases accordingly. As a result, the intensity of the laser beam required for processing the first electrode 103 most likely to adversely affect the insulating layer can be further reduced, so that a photovoltaic element array in which damage to the insulating layer is reduced can be obtained.

In claim 4, since the metal forming the first electrode is copper or an alloy containing 70 atomic% or more of copper,
It has become possible to satisfy the feature of claim 3 and improve the operational stability under high humidity. As a result, a highly reliable photovoltaic element array with high conversion efficiency can be obtained.

According to the present invention, since the insulating member is provided on the conductive substrate, it is possible to use a thin metal plate having high strength as a substrate. as a result,
A low cost photovoltaic device array suitable for continuous production is obtained.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each component suitable for carrying out the present invention, a manufacturing method and the like will be described.

(Photovoltaic Element Array) The photovoltaic element array (FIG. 1) according to the present invention will be described below in comparison with a conventional series-connected photovoltaic element array (FIG. 6) using a metal substrate. To do.

In FIG. 6, an insulating layer 602 is deposited on a conductive substrate 601 made of a thin metal plate so as to cover the entire substrate. On top of this, the first electrodes 603a, 603
b, 603c are deposited. First electrode is groove 604
It is completely separated by a and 604b. First electrode 603
May be transparent to light or opaque like metal. A semiconductor photovoltaic layer 605 is deposited on this. The semiconductor photovoltaic layer 605 has a pn junction,
A pin junction, a Schottky junction, etc. are included, and a photoelectromotive force is generated.

Further thereon, a transparent second electrode 607a,
607b and 607c are deposited. Second electrode is groove 6
It is completely separated by 07a and 607b. Groove 6
The grooves 07a and 607b are provided so as to be offset from the grooves 604a and 604b in the plane direction, and areas having a minute width X are provided between the grooves 607a and 604a and 607b and 604b.

A region 606 for electrically connecting the first electrode 603b and the second electrode 607a is provided in the region of the width X.
a, a region 606b for electrically connecting the first electrode 603c and the second electrode 607b is provided. Area 60
6a and 606b may be made of a semiconductor layer whose resistance has been lowered by means such as melting and re-solidifying by irradiation with a laser beam, or a conductive material filled in holes or grooves formed in the semiconductor layer. It may be. Since the width X does not contribute to the generation of photovoltaic power in the area X, the areas 606a and 606b are
It is better to be as narrow as possible within the necessary and sufficient range for the provision.

The semiconductor photovoltaic layer 605 directly below the grooves 607a and 607b may be removed. However, if the semiconductor photovoltaic layer 605 has a certain level of resistance in the plane direction, the structure shown in the figure is left as it is. It may be left.

Next, the function of the series-connected photovoltaic element array shown in FIG. 6 will be described. The semiconductor photovoltaic layer 605 is
Light entering from the second electrode 607 side is absorbed to generate electromotive force, and the first electrode 603a, the second electrode 607a, and the first electrode 2
03b and the second electrode 207b, and a potential difference V is generated between the first electrode 603c and the second electrode 607c. Here, by the regions 606a and 606b, the first electrode 603b and the second electrode 607a, and the first electrode 603c and the second electrode 607b.
Have the same potential, so that the adjacent first electrodes 603
a, 603b, 603c, and the adjacent second electrode 607.
a, 607b, 607c are sequentially boosted by V.

FIG. 6 shows only a part of the electromotive force element array for simplification, but in practice, such a structure is repeatedly provided as many times as necessary according to the output voltage required.

By the way, as described above, the grooves 604a, 60
4b and the regions 607a and 607b for electrical connection are provided with a laser beam, it is convenient because the manufacturing throughput is high.

However, when this type of processing is performed, the insulating layer 602 directly below the insulating layer 602 is melted and evaporated by the heat transferred during the processing to roughen the surface, the surface of the metal substrate is exposed, and heat is applied. Easy to crack due to expansion. In such a state, conduction is established between the first electrode and the metal substrate, or deposition is disturbed in the photovoltaic layer on the first electrode, leading to conduction between the first electrode and the second electrode. One or more first electrodes, eg 603
When conduction occurs in the insulating layer 602 under a and 603c, the potential difference of 2V originally generated between these electrodes becomes ineffective and the output of the solar cell is impaired. It is also dangerous because high voltage leaks to the board.

On the other hand, if the intensity of the laser beam is lowered to avoid such a fear, the separation of the first electrode or the electrical connection between the first electrode and the second electrode will be insufficient, and this The output of the solar cell will be impaired.
In order to avoid such a situation, the following characteristics are desired regarding the materials of the insulating layer and the first electrode.

(1) The thermal conductivity of the insulating layer is as high as possible so that the insulating layer itself is not damaged. When a metal is used as the substrate, the substrate has a high thermal conductivity, and thus the insulating layer itself is not damaged if the heat transmitted from above is quickly released to the substrate.

(2) The thermal conductivity of the insulating layer is low so that the processing of the first electrode and the semiconductor layer is completed in the shortest possible time.
That is, the heat loss is small, and the damage to the insulating layer is small if the processing is completed in a short time. However, obviously (1) and (2) are contradictory requirements.

(3) The first electrode should absorb the laser beam as much as possible. On the other hand, the first electrode has a function of returning the light that could not be absorbed by the semiconductor photovoltaic layer 605 back to the semiconductor and reusing it, and therefore, in principle, is a material having a high reflectance of light, in other words, a material having a low absorption. Things are desirable.

As a result of studying in view of such a situation, the inventor of the present invention has made it possible to satisfy the requirements (1) to (3) described above without contradiction. Came to remember. In FIG. 1, the components common to FIG. 6 have the last two digits of their numbers in common with FIG. 6, and therefore the difference between the configurations of FIGS. 1 and 6 will be described below.

First, the insulating layer 602, which has a single structure in FIG. 6, is composed of a stack of 102a and 102b in FIG. The insulating layer 102a is made of an insulating material having high thermal conductivity, and the insulating layer 102b is made of an insulating material having low thermal conductivity.

In this case, since the insulating layer 102b in contact with the first electrode 103 has a low thermal conductivity, there is little heat loss when the first electrode 103 and the semiconductor photovoltaic layer 105 are processed by the laser beam, and the processing is difficult. Finish in a short time. However, heat tends to accumulate on itself, and its surface may be damaged by heat to some extent. On the other hand, the insulating layer 10
2a has high thermal conductivity and easily releases the transferred heat to the metal substrate, so that heat is less accumulated and is less likely to be damaged.

That is, if the laser beam intensity is excessive, the insulating layer 102b may be damaged or completely removed in an extreme case, but since the insulating film 102a remains as it is, it functions as an insulating layer. Has no effect on.
Moreover, since the heat loss is small, the first electrode 103 and the semiconductor photovoltaic layer 105 can be processed with a relatively low laser beam intensity, and the optimum laser beam intensity range is wide.
The latitude of processing conditions becomes wider.

Although the first electrode 103 is similar in form to the first electrode 603 of FIG. 6, the present inventor has considered its material and used it in combination with the novel insulating layer described above to obtain its effect. We came up with the characteristic of the material that further enhances.

That is, as described above, the first electrode is required to have a function of returning the light, which has not been completely absorbed by the semiconductor photovoltaic layer 105, to the semiconductor again. Generally, the semiconductor material strongly absorbs light having a shorter wavelength. 0.5 μm, which is often used as a thin film semiconductor for solar cells.
In the case of hydrogenated amorphous silicon (a-Si: H), the light having a wavelength shorter than 0.7 μm is almost absorbed and does not actually reach the first electrode 103.

However, as the wavelength becomes longer than this, the proportion of the light that is transmitted gradually increases, and when the wavelength is about 0.7 μm, it becomes 50.
% Or more of the light is transmitted. In order to improve the loss of transmitted light, it is desirable that the material of the first electrode has a high reflectance for such a wavelength. The first to eliminate the loss of transmitted light as much as possible
As a material of the electrode, a metal having a high reflectance such as Ag or Al is often used.

As shown in FIG. 2, with these metals, the reflectance is certainly about 85% or more at the wavelength of 0.7 μm, which is excellent from the viewpoint of improving the transmitted light loss. However, these metals have a reflectance of 85% or more with respect to light of all wavelengths, which is inconvenient for laser processing.

At present, most Nd-YAG lasers are used in the manufacture of solar cells because of their large output power, stability, and relatively low device cost.
In the Nd-YAG laser, the fundamental wave has a wavelength of 1.06 μm.
Is often used at this wavelength, but the wavelength of 0.
It is also possible to use the second harmonic of 53 μm.

If the second harmonic of the Nd-YAG laser is used, the following characteristics will be obtained. As described above, in most cases, light having a wavelength of about 0.5 μm is mostly absorbed by the semiconductor photovoltaic layer 105, so that the material of the first electrode has a high reflectance for light having a shorter wavelength. You don't have to have one. On the contrary, if the reflectance with respect to such light is low (absorption is large), the absorption of the second harmonic of the Nd-YAG laser increases, and thus the first electrode 103 that is most likely to adversely affect the insulating layer is processed. The required laser beam intensity is low, and the damage to the insulating layer is small after all.

As described above, according to the structure of the present invention, a highly efficient and highly reliable series-connected photovoltaic element array can be obtained.

(Conductive Substrate) Various metals are used as the conductive substrate according to the present invention. Among them, stainless steel plates, zinc steel plates, aluminum plates, copper plates and the like are suitable because their prices are relatively low. These metal plates may be cut into a certain shape and used, or may be used in the form of a long sheet. In this case, since it can be wound in a coil shape, it is suitable for continuous production and can be easily stored and transported. Although the surface of the substrate may be polished, it may be used as it is if it has a good finish such as a bright annealed stainless steel plate.

(Insulating member) As an insulating member according to the present invention
Is at least 10 even under the condition of being irradiated with light. ^TenΩc
m or more, preferably 10¹²Has a specific resistance of Ωcm or more
There is a need. Also, the temperature applied during the deposition of electrodes and semiconductors
(Usually 200 ° C or higher) and for laser beam processing
The temperature to be applied at a moment
is expected. ) Must endure. None due to this constraint
There is no choice but to choose from among the features.

As described in detail above, the thermal conductivity of the insulating member has a great influence on the workability by the laser. Therefore, it is preferable that the insulating members are the insulating layers 102a and 102b having different thermal conductivities, and the functions are separated. As the insulating layer having a high thermal conductivity, for example, a diamond film (thermal conductivity 1.7
cal / cm · sec · deg)), silicon film, silicon carbide film (composition ratio of C is 0.2 or less) (heat conductivity is 0.3).
cal / (cm · sec · deg)), alumina film (thermal conductivity 0.1 cal / (cm · sec · deg)), silicon nitride film (thermal conductivity 0.05 cal / (cm · se)
c • deg)) etc. On the other hand, as an insulating layer having a low thermal conductivity, calcium fluoride (thermal conductivity of 0.02 ca
1 / (cm · sec · deg)), silicon oxide (thermal conductivity 0.01 cal / (cm · sec · deg)) and the like. According to the experiment, about 0.05 cal / at room temperature
If the thermal conductivity is larger than (cm · sec · deg)), the insulating layer 102a has a thermal conductivity of 0.05 cal / (c).
Insulating layer 102 is less than m · sec · deg))
It has been found suitable for b. These films can be deposited on the substrate by a method such as sputtering, plasma CVD, or ion plating.

(First Electrode) As the first electrode according to the present invention, a metal layer having a high reflectance such as Ag or Al is preferably used. However, as mentioned above, the wavelength is 0.5μ
It is not necessary to have a high reflectance for light shorter than m. Rather, a lower reflectance in this range absorbs the YAG laser beam (second harmonic) better, which is convenient for laser processing. From this point, Cu is a particularly preferable material.
Further, Cu may be alloyed and used for the purpose of increasing hardness and stability under high humidity.

As the alloying metal of the alloy, for example, Ag, A
1, Be, Ni, Sn, Zn and the like can be mentioned, and they can be preferably used within a composition range of about 0.1 atom% to 30 atom% without significantly impairing reflectance characteristics. These films can be deposited on the substrate by methods such as plating, sputtering, plasma CVD, and ion plating.

(Photovoltaic Layer Made of Semiconductor) As the semiconductor material forming the photovoltaic layer made of a semiconductor according to the present invention, hydrogenated amorphous silicon (a) described above is used.
-Si: H) and its alloys a-SiC: H, a-SiG
e: H and the like can be used, and it can be used as a pin junction or a Schottky junction. Microcrystalline silicon (μc-Si) can be preferably used for the p layer and the n layer of the pin junction. These semiconductors include silane (SiH ₄ ), which is a raw material gas, disilane (Si ₂ H ₆ ), tetrafluorosilane (SiF ₄ ), methane (CH ₄ ), ethane (C ₂ H ₄ ), germane (Ge).
H ₄ ), and phosphine (PH ₃ ), which is a gas for introducing a dopant, diborane (B ₂ H ₆ ), boron trifluoride (BF ₃ ), and the like can be deposited by glow discharge decomposition.
Alternatively, the semiconductor element may be used as a target and deposited by reactive sputtering in which hydrogen is introduced.

The content of the present invention is mainly based on these aS.
Although the present invention is described using an i: H-based semiconductor, the present invention can be similarly suitably implemented by using a CdS-CdTe junction, a CdS-CuInSe junction, or the like. These materials can also be obtained by sputtering or firing paste.

(Second Electrode) Second electrode 10 according to the present invention
7, that is, the material of the transparent conductive layer is, for example, indium oxide / tin (ITO), zinc oxide (ZnO), cadmium oxide (CdO), cadmium stannate (Cd _2).
A metal oxide such as SnO ₄ ) can be used. These materials can reduce the resistance to about 10 ⁻⁴ Ωcm. Further, if the thickness of the film is set to 1 / 4n (n is the refractive index of the transparent conductive layer) of the wavelength of light that has the highest sensitivity as a solar cell, an antireflection effect is obtained and the output current of the solar cell is improved. I can.

(Laser Processing) In the laser processing according to the present invention, for example, YAG laser (main oscillation wavelength = 1.0
6 μm), CO ₂ laser (main oscillation wavelength = 10.6 μm)
m), excimer laser (main oscillation wavelength = 0.9 μm)
Etc. are preferably used. The YAG lasers are the most used for processing solar cells. 1.06μ for YAG laser
In addition to m, the second harmonic (oscillation wavelength = 0.53 μm) can also be used by using a nonlinear optical element together. YA
The G laser can also perform continuous oscillation operation, but is often used in Q switch pulse oscillation operation in order to obtain high peak power. The frequency of the Q switch pulse oscillation is usually about several kHz to several tens of kHz, and the duration of one pulse is about 100 nsec. The oscillation mode is T
The EM00 mode has a clean intensity distribution in the beam and is easy to use. An outline of the optical form for laser processing is shown in FIG. 301
Is the laser body. If necessary, a Q switch and a non-linear optical element are incorporated therein. A power source 302 turns on a laser excitation light source. A cooling device 303 circulates cooling water. An output laser beam 304 is bent by 90 degrees by a dichroic mirror 305 and focused on a sample 307 by a lens 306. The sample 307 is mounted on the stage 308,
The stage 308 is moved horizontally by the controller 309 at a predetermined speed, and the beam scans the sample surface. For large samples, use a polygon mirror
The beam may be moved. The light from the illumination light source 310 is collimated by the lens 311, bent 90 degrees by the dichroic mirror 312, and illuminates the sample 307. The processing situation is photographed by the ITV camera 314 and can be observed on the spot on the monitor 315.

Hereinafter, a preliminary experiment conducted to show the effect of the present invention and the result thereof will be described.

(Preliminary Experiment 1) In FIG. 6, as the substrate 601, stainless steel having a size of 10 cm × 10 cm and a thickness of 0.2 mm was used. This substrate has sufficient flexibility. On top of this, as an insulating layer 602, silane (SiH
₄ ) and ethylene (C ₂ H ₄ ) were decomposed by glow discharge to deposit a 1 μm thick SiC film. According to the analysis, this film is C
Of about 20% and its specific resistance was about 10 ¹⁴ Ωcm. The thermal conductivity of this film is about 0.3 cal / (cm · se
c · deg). Subsequently, a sample A is prepared on this.

On the same stainless steel substrate, as another insulative layer 602, silica glass having a thickness of 1 μm was formed by a target of silica glass by an RF sputtering method.
An O ₂ film was deposited. The specific resistance of this film was 10 ¹⁵ Ωcm or more and could not be measured. The thermal conductivity of this film is about 0.005c
al / (cm · sec · deg). Subsequently, a sample B is prepared on this.

An insulating layer is formed on the same substrate as the samples A and B in FIG.
A SiC film having a thickness of 0.1 μm is deposited as 102a.
In addition, as a thickness insulating layer 102b, S of 0.3 μm
iO ₂The film was deposited. The SiC film and SiO used here₂film
Were manufactured in the same manner as in Sample 1 and Sample 2, respectively. pull
Subsequently, a sample C is prepared on this.

The first electrode 60 is formed on each substrate by the sputtering method.
As 3 or 103, Ag was deposited to a thickness of 0.1 μm. After that, with Nd-YAG laser beam (second harmonic),
The groove 604 or 104 having a width of 100 μm was cut, and the Ag layer was divided into 10 at intervals of about 1 cm (laser processing 1).

Then, by glow discharge decomposition, a-S
An i: H semiconductor photovoltaic layer 605 or 105 was deposited. Here, the semiconductor photovoltaic layer 605 or 105 is an n-layer having a thickness of about 10 nm doped with phosphorus (P), an i-layer having a thickness of 500 nm (= 0.5 μm) not doped with impurities, and boron (B). P-doped about 10 nm thick
It consists of layers. Further, as the second electrode 607 or 107, about 65 nm of ITO (indium oxide-tin) was deposited thereon by the RF sputtering method. This second electrode 6
The thickness of 07 or 107 is set so that it also serves as an antireflection film. Then, an Nd-YAG laser beam (fundamental wave) is used to cut the groove 607 or 108 having a width of 100 μm
The O layer was divided into 10 pieces every 1 cm in width (laser processing 2).

Groove 604 and groove 607 or groove 104 and groove 10
8 was shifted by about 300 μm (= X). Finally, between the groove 604 and the groove 607 or between the groove 104 and the groove 108, Nd-YAG
Irradiate with a laser beam (second harmonic), and the first electrode 60
3 and the second electrode 607 or the first electrode 103 and the second electrode 10
7 were connected (laser processing 3).

By the last irradiation of the laser beam, a
It is considered that the beam-irradiated portion of the —Si: H photovoltaic layer 605 or 105 was melted, re-solidified, and crystallized to lower the resistance. In this way, a photovoltaic element array connected in series in 10 stages, Sample A, Sample B, and Sample C were produced.

The photoelectric conversion characteristics of the sample thus produced were measured under a solar simulator of AM-1.5 to evaluate the conversion efficiency. In addition to this, IT
A single element with an area of 1 cm ² was prepared by depositing O using a mask, and the conversion efficiency was evaluated as a standard wipe.

In an array with series connection such as the sample of this experiment, the area of the grooves (104 and 108 in FIG. 1) provided in the first electrode and the second electrode and the region of width X between these grooves are Since a loss such as an area occurs, even if the groove and the electrical connection portion can be ideally formed, the conversion efficiency as a solar cell is slightly lower than that of the standard sample. If the insulating layer becomes conductive or the semiconductor is damaged due to the formation of grooves or electrical connections,
Furthermore, the conversion efficiency will decrease.

Next, in order to evaluate the influence of the laser beam, the intensity of the laser beam was changed stepwise by laser processing 1 and 3 to prepare a sample. The correlation between the laser beam intensity and the conversion efficiency is shown.

(Preliminary Experiment 2) The influence of the beam intensity in the laser processing 3 was examined. The continuous oscillation output of the laser was fixed at 1 W with the second harmonic, and the beam intensity was adjusted by adjusting the filter (the condition without a filter is intensity 1). The frequency of laser Q-switch pulse oscillation is 4
It is estimated that the pulse duration is about 100 nsec. The beam feed rate is 5 cm / se
c. Regarding the laser beam intensity in laser processing 2-3, standard conditions were set for each sample.

[0082]

[Table 1] ⊚ = equivalent to the standard sample (conversion efficiency is 95% or more of the standard sample), ◯ = almost equivalent to the standard sample (95 to 80%), Δ = inferior characteristic (85 to 50%), x = poor characteristic (50 to 50%) 0%)

In Sample A, the optimum value was obtained at a high beam intensity. According to the microscopic observation, the groove 604 for separating the first electrode 603 was not cut at the place where the beam intensity was weak. Further, at the beam intensity 1, the insulating layer was cracked.

In Sample B, the optimum value was obtained at a weak beam intensity. Microscopic observation revealed that the insulating layer also had a groove at a place where the beam intensity was high.

In the sample C, the beam intensity of 1/4 was the optimum value, but practically usable characteristics were obtained even in the range of the beam intensity of 1/2 to 1/8, and the condition range far wider than those of the samples A and B. I found that the groove would be cut.

(Preliminary Experiment 3) The influence of the beam intensity in the laser process 3 was examined. The continuous wave output of the laser was fixed at 1 W (second harmonic), and the beam intensity was adjusted by adjusting the filter (the condition without the filter was intensity 1).
And). The frequency of laser Q-switched pulse oscillation is 4 kHz, and the duration of the pulse is estimated to be about 100 ns. The beam feed rate is 2 cm / se.
c. Further, with regard to Steps 2 and 3, standard conditions were set for each sample.

[0087]

[Table 2] ⊚ = equivalent to the standard sample (conversion efficiency is 95% or more of the standard sample), ∘ = almost equal to the standard sample (95 to 80%), Δ = inferior property (85 to 80%), x = inferior property (50 to 50) 0%)

In Sample A, the optimum value was found in the place where the beam intensity was strong. Microscopic observation revealed that melting of the amorphous silicon did not occur at the connection portion 606 at a place where the beam intensity was weak, and the resistance did not decrease. At the beam intensity of 1, the insulating layer was cracked.

In sample B, the optimum value was obtained at a weak beam intensity. Microscopic observation revealed that the insulating layer also had a groove at a place where the beam intensity was high.

For sample C, the beam intensities of 1/4 and 1/8
Was the optimum value, but it was found that the characteristics that could be practically used were obtained even in the range of the beam intensity of 1/2 to 1/16, and that the connection was possible in a much wider condition range than the sample A and the sample B.

(Preliminary Experiment 4) Ag as the first electrode 103
Sample C except that 0.1 μm Cu was used instead of
Sample D was made in the same process as above. Experiment 1 on sample D
The effect of the beam intensity in the laser process 1 was examined in the same manner as in.

[0092]

[Table 3] ⊚ = equivalent to the standard sample (conversion efficiency is 95% or more of the standard sample), ∘ = almost equal to the standard sample (95 to 80%), Δ = inferior characteristic (85 to 50%), x = poor characteristic (50 to 50) 0%)

Here, it has been found that in the sample D, good characteristics can be obtained even with a beam intensity lower than that of the sample C, and the groove can be cut in a wider condition range.

By the above Experiments 1 to 3, it was found that by forming the insulating layer of the present invention, it is possible to manufacture a series-connected photovoltaic element array in a wider condition range than before. Also, under optimal conditions, its characteristics are superior to the conventional series-connected photovoltaic element array. Furthermore, by selecting the material of the first electrode according to the present invention, the effect is further enhanced.

[0095]

EXAMPLES Hereinafter, the photovoltaic element array according to the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 This example is different from the above preliminary experiment in that a transparent conductive layer was provided between the first electrode and the photovoltaic layer made of a semiconductor.

FIG. 4 is a schematic sectional view of the photovoltaic element array of this example. In FIG. 4, the transparent conductive layer 409 is provided on the first electrode 403, and the photovoltaic layer 405 made of a semiconductor is provided on the transparent conductive layer 409. In addition, the first electrode 403 and the transparent conductive layer 409 are formed on the three portions (403a above the 403a) by the grooves 404a and 404b that are electrically divided.
09a is laminated, a portion 409b is laminated on 403b, and a portion 409c is laminated on 403c).

The parts other than the transparent conductive layer are the same as the series-connected photovoltaic element array of FIG. 1, and the last two digits of the numbers of the respective constituent elements are common.

The transparent conductive layer 409 of this example can increase the reflection of light on the surface of the first electrode (Ag in this case), increase the output current of the solar cell, and have an appropriate resistance. Therefore, even if a defective portion occurs in the semiconductor, it has a function of limiting the excess current flowing through this portion and suppressing the deterioration of the characteristics of the solar cell as a whole.

The method for manufacturing the photovoltaic element array of this example will be described below in accordance with steps. (1) As the substrate 401, stainless steel with a size of 10 cm square and a thickness of 0.2 mm was used. This substrate was set in a DC magnetron sputtering device, and first a polycrystalline silicon target was used to set the argon (A
r), ethylene (C ₂ H ₄ ), and hydrogen (H ₂ ) as atmosphere gases, a SiC film having a thickness of 0.7 μm is deposited to form the insulating layer 40.
2a.

(2) The sample of the above (1) is set in another RF magnetron sputtering apparatus that can use three targets, and first a quartz glass target is used, Ar is used as an atmospheric gas, and the thickness is 0.3 μm. Of SiO ₂ film was deposited as an insulating layer 402b. Next, using a Ag target and using Ar as an atmospheric gas, a 0.1 μm-thick Ag film was deposited to form a first electrode 403. Furthermore, zinc oxide (Zn
O) A target was used and Ar was used as an atmosphere gas to deposit a ZnO film having a thickness of 1.0 μm to form a transparent conductive layer 409.

(3) Stage 3 of the laser beam machine shown in FIG.
The sample 307 of (2) above was set on the 08. Nd
While oscillating the YAG laser 301, the stage 30
8 is moved to scan a laser beam, a groove 404 having a width of 100 μm is cut, and two layers of ZnO and Ag have a width of about 1
It was divided into 10 for each cm. At this time, the laser output during continuous oscillation was 4 W, the oscillation frequency was 4 kHz, and the scanning speed was 5 cm.
/ Sec.

(4) A photovoltaic layer 405 made of a semiconductor of amorphous silicon was deposited on the sample of (3). The sample was set in a parallel plate capacitively coupled glow discharge device, and silane (SiH ₄ ) and phosphine (P
H ₃ ), hydrogen (H ₂ ) are flowed to adjust the pressure to 1 Torr, the sample is heated to 250 ° C., a high frequency voltage is applied between the electrodes to generate glow discharge plasma, and phosphorus (P) is doped. An n-layer (not shown) having a thickness of about 20 nm was deposited.

Next, silane (SiH ₄ ) and hydrogen (H ₂ ) were flowed to adjust the pressure to 1 Torr, the sample was heated to 200 ° C., a high frequency voltage was applied between the electrodes to generate glow discharge plasma. , An i-layer (not shown) having a thickness of 400 nm (= 0.4 μm) was deposited. Furthermore, silane (Si
H ₄ ), diborane (B ₂ H ₆ ), hydrogen (H ₂ ) are flowed to adjust the pressure to 1 Torr, the sample is heated to 150 ° C., a high frequency voltage is applied between the electrodes to generate glow discharge plasma. , A p-layer (not shown) having a thickness of about 10 nm doped with boron (B) was deposited. An electron diffraction experiment was conducted, and it was found that the p layer was microcrystallized.

(5) The second electrode 4 is placed on the sample of (4) above.
07 was formed. The sample was set in a DC magnetron sputtering device, and an ITO film was deposited to a thickness of about 65 nm as the second electrode 407 using an ITO (indium-tin oxide) target and Ar as an atmospheric gas. This second electrode 407
Has a thickness set so as to also serve as an antireflection film.

(6) The sample of (5) above was set again in the laser beam machine of FIG. 3 to form the groove 408 of the second electrode 407. While oscillating the Nd-YAG laser, the stage 308 is moved to scan the laser beam, and the width is 10
Cut the groove 408 of 0 μm and put the ITO layer on every 1 cm width.
It was divided into 0. At this time, the output during continuous oscillation of the laser is 1
W, oscillation frequency was 4 kHz, and scanning speed was 1 cm / sec. Further, the groove 408 is approximately 300 μm (= X) with the groove 404.
It was formed by shifting.

(7) In the sample of (6) above, the groove 40
4 and the groove 408 are irradiated with an Nd-YAG laser beam (second harmonic), and the transparent conductive layer 409 and the second electrode 40 are irradiated.
7 were electrically connected. At this time, the laser output during continuous oscillation is 1 W, the oscillation frequency is 4 kHz, and the scanning speed is 1
It was set to 0 cm / sec. (8) A photovoltaic element array in which the photovoltaic elements produced by the above steps (1) to (7) were connected in series in 10 stages was produced.

This photovoltaic element array was provided with AM-1.5.
It was set in a solar simulator with an illuminance of 100 mW / cm ² and its photoelectric conversion characteristics were evaluated.

As a result, the photovoltaic element array (area: 10 cm ² ) of this example showed almost the same conversion efficiency as the standard sample (single element connected in series with an area of 1 cm ² ).

On the other hand, for comparison, a photovoltaic element array in which the insulating layer was a single layer film made of SiC and a photovoltaic element array in which the insulating layer was a single layer film made of SiO ₂ were prepared. The photoelectric conversion characteristics were examined in the same manner as this example. As a result, it was found that the conversion efficiency of both photovoltaic element arrays was lower than that of the standard sample described above.

Therefore, it was judged that the photovoltaic element array of the present invention in which the transparent conductive layer was provided between the first electrode and the photovoltaic layer made of a semiconductor could realize excellent conversion efficiency.

Example 2 In this example, a diamond film is used as the insulating layer 402a and MgF is used as the insulating layer 402b.
_The difference from the preliminary experiment is that _two films and a ZnO film as a transparent conductive layer were provided.

In the following, the photovoltaic element array of this example is manufactured.
The manufacturing method will be described according to steps. (1) The substrate 401 has a size of 10 cm square and is thick.
A stainless steel having a size of 0.2 mm was used. this
Set the substrate on the ECR discharge device and
₂H_Four), Hydrogen (H₂), The frequency is 2.45G
Introducing a microwave of Hz to bring the substrate temperature to 500 ° C.
Then, a diamond film having a thickness of 0.7 μm is deposited to form an insulating layer 5
02a.

(2) The sample of the above (1) is set in an RF magnetron sputtering apparatus which can use three targets, and a magnesium fluoride (MgF ₂ ) target is used, Ar is used as an atmospheric gas, and a thickness of 0 is obtained. 0.3 μm Mg
An F ₂ film was deposited to form an insulating layer 402b. Next, copper (C
u) Using a target, using Ar as an atmospheric gas, a Cu film having a thickness of 0.1 μm was deposited and a first electrode 403 was deposited. Further, using a zinc oxide (ZnO) target,
A ZnO film having a thickness of 1.0 μm was deposited using Ar as an atmosphere gas to form a transparent conductive layer 409.

(3) Using the laser beam machine shown in FIG. 3, the sample of (2) above was cut into a groove 404 having a width of 100 μm, and Zn was formed.
The O and Ag layers were divided into 10 parts every 1 cm in width. At this time, the laser output during continuous oscillation was 1 W (second harmonic), the oscillation frequency was 4 kHz, and the scanning speed was 5 cm / sec.
Good results were obtained with a lower beam intensity required for laser processing than in the case of Example 1.

(4) A photovoltaic layer 405 made of a semiconductor of amorphous silicon was deposited on the sample of (3). However, only the following i layer formation conditions differ from Example 1
Others were the same as in Example 1. For the i layer, a gas obtained by adding germane (GeH ₄ ) to SiH ₄ —H ₂ as a source gas is used, and amorphous silicon germanium (a-Si) is used.
Ge: H) was formed.

(5) The steps following (4) above are the same as those in Example 1.
Same as. (6) A photovoltaic element array in which the photovoltaic elements produced by the above steps (1) to (5) were connected in series in 10 stages was produced.

This photovoltaic element array was provided with AM-1.5.
It was set in a solar simulator with an illuminance of 100 mW / cm ² and its photoelectric conversion characteristics were evaluated.

As a result, the photovoltaic element array (i
The layer: a-SiGe: H) provided a larger output current than the photovoltaic element array of Example 1 (i layer: a-Si: H). The reason is that in the wavelength range of incident sunlight, even longer wavelength portions can be used.

Further, the photovoltaic element array (area 1
0 cm ² ) showed almost the same conversion efficiency as the standard sample (single element connected in series with an area of 1 cm ² ).

(Embodiment 3) In this embodiment, as the conductive substrate, stainless steel having a width of 10 cm, a thickness of 0.1 mm and a length of 300 m is used, and the roll-to-roll shown in FIG.
This is different from the preliminary experiment in that a photovoltaic device array having the configuration shown in FIG. 4 was produced by a roll device.

The method of manufacturing the photovoltaic element array of this example will be described below in accordance with steps. (1) As the conductive substrate made of stainless steel, it is washed with an alkaline cleaning liquid (temperature: 60 ° C.), then rinsed with ion-exchanged water, dried with warm air, and then wound into a coil, which is used as the substrate. I was there.

(2) The insulating layer 402a to the transparent conductive layer 409 were deposited on the substrate by using the roll-to-roll sputtering device shown in FIG. When depositing each layer on a stainless steel substrate, the delivery chamber 50
The substrate is sent out from the roll 507 set to 1 at a constant speed, passes through each film forming chamber, and then is wound into the winding chamber 50.
It is wound on a roll 509 at No. 6.

In each film forming chamber, a thin film was formed under the following conditions. (2-1) In the deposition chamber 502, a DC voltage is applied to the polycrystalline silicon target 510 from a power source 512, and argon (Ar), ethylene (C ₂ H ₄ ) and hydrogen (H ₂ ) are used as an atmosphere gas to form a substrate 508. While heating the substrate from the back surface of the substrate to a temperature of 300 ° C. with a heater 511, a 0.7 μm thick S
An iC film was deposited to form an insulating layer 402a.

(2-2) On the insulating layer 402a, in a deposition chamber 503, a quartz glass target is used, Ar is used as an atmospheric gas, the substrate is set to 300 ° C., and the thickness is 0.3 μm.
Of SiO ₂ film was deposited as an insulating layer 402b. (2-3) The configuration inside the deposition chamber 503 is similar to that of the deposition chamber 502.

(2-4) Using a Cu target in the deposition chamber 504 and using Ar as an atmospheric gas, a thickness of 0.1 μm
Cu film was deposited and used as the first electrode 403. (2-5) In the deposition chamber 505, a zinc oxide (ZnO) target is used and Ar is used as an atmospheric gas to have a thickness of 1.0.
A μm ZnO film was deposited to form a transparent conductive layer 409.

(3) While the rolled-up roll 509 is being rewound and conveyed, the surface of the transparent conductive layer 409 is scanned with the laser beam of the Nd-YAG laser in the width direction of the substrate by the rotating polygon mirror. While synchronizing the pulse oscillation, the width extending in the longitudinal direction of the substrate is 100 μm.
The groove 404 was cut, and the ZnO and Ag layers were divided into 10 at intervals of about 1 cm. At this time, the output during continuous oscillation of the laser is 1
0 W (second harmonic), the oscillation frequency was 4 kHz, and the substrate transport speed was 5 cm / sec.

(4) A photovoltaic layer 405 made of a tandem type semiconductor was deposited by using a roll-to-roll glow discharge deposition apparatus as disclosed in US Pat. No. 4,369,730. . This photovoltaic layer 405 is formed by adding germane (GeH ₄ ) as an i-layer to SiH ₄ and H ₂ and then depositing the amorphous silicon germanium (a-S).
It is a structure in which a bottom cell using iGe: H) and a top cell using amorphous silicon (a-Si: H) as an i layer are stacked.

In the tandem type photovoltaic layer, the portion of the incident sunlight having a wavelength shorter than 500 nm is mainly absorbed by the top cell, and the portion of the incident sunlight which is not completely absorbed by the upper cell is longer than 500 nm is efficiently emitted by the bottom cell. Can be used. Moreover, since the two cells are serialized, it is possible to obtain a high output voltage.

(5) On the sample of (4) above, again using a roll-to-roll sputtering apparatus (only one deposition chamber), an ITO (indium oxide-tin) target was used, and Ar was used as an atmosphere gas. As the second electrode 407, an ITO film was deposited to a thickness of about 65 nm.

(6) The surface of the second electrode 407 is conveyed while the wound roll 509 is being conveyed while being rewound again.
While scanning in the width direction of the substrate with a laser beam of an Nd-YAG laser, pulse oscillation was synchronized to cut a groove 408 having a width of 100 μm extending in the longitudinal direction of the substrate, and the ITO layer was divided into 10 parts every 1 cm width. .

At this time, the output during continuous oscillation of the laser is 5
W, oscillation frequency was 4 kHz, and scanning speed was 5 cm / sec. The groove 408 was formed so as to be offset from the groove 404 by about 300 μm (= X). At the same time, the pulsed oscillation is synchronized with the transparent conductive layer 40 while scanning in the width direction of the substrate with the laser beam (second harmonic) of another Nd-YAG laser.
9 and the second electrode 407 were electrically connected. At this time, the laser output during continuous oscillation is 5 W, and the oscillation frequency is 4 kHz.
It was z.

(7) The roll after laser processing is
It was cut every 10 cm in length. (8) A photovoltaic element array in which the photovoltaic elements produced by the above steps (1) to (7) were connected in series in 10 stages was produced.

This photovoltaic element array was provided with AM-1.5.
It was set in a solar simulator with an illuminance of 100 mW / cm ² and its photoelectric conversion characteristics were evaluated.

As a result, 95% of the manufactured samples showed almost the same conversion efficiency as the single element connected in series with an area of 1 cm ² . Therefore, it has been found that the photovoltaic element array having the configuration of the present invention has high mass productivity.

[0136]

As described above, according to the invention of claim 1, the thermal damage to the insulating layer in the laser processing for providing the electrical contact portion between the first electrode and the second electrode is reduced. Therefore, a photovoltaic element array having a wide latitude of processing conditions can be obtained.

According to the second aspect of the invention, a photovoltaic element array capable of further suppressing the thermal damage of the insulating layer can be obtained.

According to the third aspect of the present invention, there can be obtained a photovoltaic element array which is easy to process with a laser and which has the first electrode as a reflective layer having a high effective sunlight reflectance.

According to the invention of claim 4, a photovoltaic element array satisfying the characteristics of claim 3 and excellent in stability under high humidity can be obtained.

According to the fifth aspect of the present invention, a photovoltaic element array that is suitable for continuous production and has a low cost can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a photovoltaic element array according to the present invention.

FIG. 2 is a graph showing spectral reflectances of various metals examined when forming the first electrode in the photovoltaic element array according to the present invention.

FIG. 3 is a schematic view showing a configuration of an Nd-YAG laser beam machine used when forming the photovoltaic element array according to the present invention.

FIG. 4 is a schematic cross-sectional view showing another example of the photovoltaic element array according to the present invention.

FIG. 5 is a schematic cross-sectional view showing an example of a roll-to-roll sputtering apparatus suitable for manufacturing the photovoltaic element array according to the present invention.

FIG. 6 is a schematic cross-sectional view showing a conventional photovoltaic element array.

[Explanation of symbols]

 101, 401, 601 Conductive substrate, 102, 402, 602 Insulating layer, 103, 403, 603 First electrode, 104, 404, 604 Groove separating first electrode, 105, 405, 605 Photovoltaic semiconductor Layer, 106, 406, 606 electrical contact part, 107, 407, 607 second electrode, 108, 408, 608 groove separating second electrode, 409 transparent conductive layer, 301 YAG laser, 307 sample, 310 illumination light source, 314 ITV camera, 501 delivery chamber, 502, 503, 504, 505 deposition chamber, 506 winding chamber, 507 substrate coil, 510 target.

Claims (5)

[Claims] 1. A plurality of first electrodes provided on an insulating member and electrically divided by a groove, a photovoltaic layer made of a semiconductor provided on the first electrodes, and the photovoltaic. A plurality of second electrodes provided on the layer and electrically separated by a groove at a position displaced from the groove of the first electrode in the plane direction by a distance X and parallel to the groove of the first electrode. A photovoltaic element array comprising an electrode and an electrical contact portion between the first electrode and the second electrode within a range of the distance X in the photovoltaic layer, wherein the insulating member is A photovoltaic element array comprising a first insulating layer having a high thermal conductivity and a second insulating layer having a low thermal conductivity provided on the first insulating layer. 2. The thermal conductivity of the first insulating layer is 0.05 c
Al / (cm · sec · deg) or more, and the second
The thermal conductivity of the insulating layer is 0.05 cal / (cm ・ sec ・
The photovoltaic element array according to claim 1, wherein the photovoltaic element array is less than deg). 3. The first electrode is made of a metal having a reflectance of 85% or more for light having a wavelength of 0.7 μm and a reflectance of 70% or less for light having a wavelength of 0.53 μm. The photovoltaic element array according to claim 1 or 2, wherein. 4. The photovoltaic element array according to claim 1, wherein the metal forming the first electrode is copper or an alloy containing 70 atomic% or more of copper. 5. The photovoltaic element array according to claim 1, wherein the insulating member is provided on a conductive substrate.