JPS61112384A - Solar battery and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve productivity, by bonding at least one of electrode layers to a photovoltaic layer by a conducting bonding layer, and separately preparing the photovoltaic layer and the electrode layer. CONSTITUTION:An electrode sheet, which is separately prepared, is bonded to a semiconductor layer of a photovoltaic layer by a conducting bonding agent. As the conducting bonding layer, a dispersing type conducting macromolecular- resin bonding agent prepared by the following method is used: conducting oxide fine particles of tin oxide, indium oxide, titanium oxide and the like are dispersed into a macromolecular resin for binder such as polyester resin, acrylic resin, polyvinyl resin, epoxy resin, polyurethane resin, silicon resin and the like. It is desirable to have resistivity of 10<6>cmOMEGA or less in order that a light current generated in the semiconductor photovoltaic layer is transmitted to electrode layers without loss by said conducting bonding layer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application] The present invention relates to a solar cell having a semiconductor as a photovoltaic layer and a method for manufacturing the same, and more particularly to a solar cell with high yield and productivity and a method for manufacturing the same.

[Prior art] As a solar cell using a semiconductor as a photovoltaic layer, single crystal S
i, polycrystalline S1. Silicon solar cell with amorphous S1 as an electromotive force layer, GLI AS, Ill P.

Various types of solar cells have been proposed in which an electromotive force layer is made of a compound semiconductor such as Cds/Cu 2 S or Cd Te /Cd 2 S. Among these, amorphous silicon solar cells can be deposited uniformly and continuously over a wide area at low substrate temperatures by using glow discharge decomposition of silane gas, disilane gas, etc., and can also be deposited on various substrates such as polymer films, glass, ceramics, and metal foils. can be selected, and it is widely researched because it is very advantageous in terms of cost. However, there are the following manufacturing problems. The basic structure of an amorphous silicon semiconductor solar cell is mainly a laminated structure of metal electrode layer/amorphous semiconductor layer/transparent electrode layer provided on the various substrates mentioned above. layer.

Transparent electrode layer or transparent electrode layer, amorphous semiconductor layer.

Metal electrode layers are sequentially deposited on each layer using a film forming method such as a physical method such as a vacuum evaporation method or a sputtering method, or a chemical method such as a glow discharge decomposition method or a photo-CVD method.

For example, in the case of sequentially depositing a metal nail electrode layer, an amorphous semiconductor layer, and a transparent electrode layer, if a module is created by patterning solar cells on the same substrate, a vapor deposition method using a mask, sputtering method, dry method using resist,
Alternatively, a method has been adopted in which the transparent electrode layer is patterned by a wet etching method.

By the way, in the case of buttering using a mask.

Since a metal mask or the like must be brought into direct contact with the surface of the amorphous semiconductor layer, the amorphous semiconductor layer itself is easily damaged.
There is a problem of lowering yield. Continuously wider,
In order to create a long, large-area solar cell, a wide and long mask with many openings is brought into close contact with the substrate and moved accurately.1. f h tf , i, and there are problems such as pattern deviation.

On the other hand, in the case of patterning using cysts, not only is it easy to damage the amorphous semiconductor layer itself, but there are also problems that require multiple IhT culms, such as resist attachment, etching, and resist removal. There is.

[Object of the Invention] An object of the present invention is to solve the above problems and provide a solar cell with high productivity and high yield, and a method for manufacturing the same.

[Structure of the invention] The above objects are achieved by the invention as follows.

In other words, the present invention provides a photovoltaic layer made of a semiconductor, and a first layer provided on both sides of the photovoltaic layer, at least one of which is transparent.
and a second electrode layer, wherein at least one of the electrode layers is bonded to the photovoltaic layer by a conductive adhesive layer.
When manufacturing the solar cell of the first invention, an electrode and a photovoltaic layer or a photovoltaic layer formed by laminating a photovoltaic layer on an electrode layer are prepared in advance. A second invention provides a method for manufacturing a solar cell, which is characterized in that the solar cells are then bonded together using a conductive adhesive layer.

The present invention described above is contrary to the conventional knowledge that it is essential to form an electrode layer directly on the semiconductor layer of the photovoltaic layer by a film forming means in order to obtain a good electrical connection. It was discovered that by adhering a separately prepared electrode sheet onto the layer using a conductive adhesive, it was surprisingly possible to obtain a solar cell with performance comparable to that of conventional directly laminated solar cells. It is.

From the above-described configuration, the present invention has the following various effects.

In other words, since the photovoltaic layer and the electrode layer can be fabricated completely independently and in parallel, productivity is greatly increased compared to conventional methods, and the quality of the photovoltaic layer and electrode layer can be controlled independently. At the same time, since there are no problems associated with patterning as described above, the yield can be greatly increased.

In addition, in the present invention, since the electrode layer is formed on a separate substrate independently of the semiconductor layer of the photovoltaic layer, various electrode formation methods including vacuum evaporation can be used. Continuation is easy when manufacturing solar cells. In addition, the electrode layer can be easily formed using various methods such as the laser scribing method, which was difficult to use in the past due to damage to the semiconductor layer, as well as the mask evaporation method, and is useful for patterning solar cells. can also be done easily.

Furthermore, since it is possible to individually select the substrates for the electrode layer and photovoltaic laminate to be bonded via the conductive adhesive layer, the surface protection ability suitable for each application required for applying the solar cell, Durable performance can be created.

From the above, the present invention is particularly advantageous for those in which the electrode layer and the photovoltaic layer are formed of thin films in terms of productivity and the like.

Note that the thin film herein includes ribbons, sheets, foils, films, and the like.

Further, when bonding using the conductive adhesive layer, from the viewpoint of productivity, it is advantageous to carry out the bonding continuously while transferring the electrode layer and the photovoltaic layer or photovoltaic laminate to be bonded using a transfer means. At this time, if the electrode layer and the photovoltaic layer or the photovoltaic laminate are formed on separate long substrates, in addition to the above point, it is possible to continuously form the electrode layer and the photovoltaic layer or the photovoltaic laminate from the formation of each layer to the final product. It can be manufactured and a very productive process can be obtained.

By the way, as the semiconductor layer of the photovoltaic layer of the present invention, crystalline silicon, polycrystalline silicon, amorphous silicon, gallium arsenide, indulumin, Cd S/CU 2 S, Cd
■group such as Te/CdS, I[-VT group, I-
A group V semiconductor layer is used.

In the case of a normal electrode layer mainly made of metal, A
n, A(1, Au, Pt, Cu, Ni.

Single-layer and/or multi-layer laminated films of single metals such as Cr, Fe, Mo, W, Ti, and Cs and/or their alloy metal layers are applied, and if necessary, transparent conductive layers are laminated as electrode layers. Applicable. Note that various manufacturing methods can be applied to form the electrode layer, such as a physical method such as a sputtering method and a vacuum evaporation method, a chemical method such as plating, and a method in which a metal film is laminated.
When the P1 electrode layer is a transparent electrode layer, the main components are conductive oxides such as indium oxide, tin oxide, cadmium stannate, and titanium oxide, thin metal films such as AU, Pt, and Pd, and A11L. A conductive laminate, etc., in which thin layers of conductive oxide layers are laminated in a sandwich-like manner, is used. These transparent electrode layers can be formed by known methods such as vacuum evaporation and sputtering, and have a surface resistance of 10,000 Ω/hole or less, preferably 1,000 Ω/hole or less, and a visible light transmittance of 50. % or more is desirable. When forming a large area solar cell, in order to avoid output loss due to resistance in the transparent electrode layer, a comb-shaped highly conductive metal layer is provided as a collection electrode at the substrate/transparent electrode layer interface or on the surface of the transparent electrode layer. You can also do it.

Further, as the substrate of the laminate on which the transparent electrode layer is deposited, a light-transmitting material such as a polymer film, a polymer resin plate, or glass is used.

The conductive adhesive layer of the present invention may be polyester resin, acrylic resin, polyvinyl resin, epoxy resin, polyester resin, acrylic resin, polyvinyl resin, epoxy resin, or
A dispersion-type conductive polymer resin adhesive is used in which conductive fine particles of an oxide such as 1M indium tin oxide or titanium oxide are dispersed in a polymer resin for a binder such as a Frethane resin or a silicone resin. Further, conductive polymer resins such as polyvinyl carbazole can also be used. Furthermore, it is also possible to use a thin layer of a low melting point metal such as solder as an adhesive layer. In terms of adhesion and durability, conductive polymer resin,
In particular, a dispersed conductive polymer resin is preferably a thin layer of a low melting point metal from the viewpoint of electrical resistance, and is selected depending on the application. These conductive polymer resins can be used using the spinner method, barcode method, and doctor blade method.

It is applied to the electrode layer and/or the surface of the semiconductor layer to be bonded using a method such as screen printing.In order to reduce damage to the semiconductor layer, it is preferable to apply it to the surface of the electrode layer. In order for the adhesive layer to perform the role of transmitting the photocurrent generated in the semiconductor photovoltaic layer to the electrode layer without loss, it is desirable that the adhesive layer has a resistivity of 106 cmΩ or less.
The thickness of the adhesive layer is not particularly limited, but the adhesive strength, durability,
electrical resistance.

Although it is related to many factors such as light transmittance and needs to be determined experimentally, it is usually selected in the range of 0.01 to 10μ.

Further, the electrically conductive adhesive layer can also be divided into electrically conductive regions by patterning using a laser scribing method, edge leg method, etc., or by patterning coating using screen printing. The solar cell of the present invention can be formed by laminating the electrode layer provided with the conductive adhesive layer and the semiconductor layer, or, if each layer is patterned, properly aligning each pattern and laminating them.

The present invention will be explained below with reference to Examples.

[Example 1] A polyester film with a thickness of 100 μm was used as a substrate of a photovoltaic laminate in which an amorphous semiconductor layer was laminated as a photovoltaic layer on a metal electrode layer. On this polyester film, an aluminum layer was continuously deposited as a metal electrode layer to a thickness of 0.4 μm, and a stainless steel layer was further deposited to a thickness of 100 μm using a continuous sputtering device.

An amorphous silicon layer is used as an amorphous semiconductor layer in JP-A-59-
3 of the internal electrode type similar to that disclosed in Publication No. 34668.
A high-frequency (13,56MH7) glow discharge device with a chamber separation method was used to set the metal electrode layer on the metal electrode layer as follows ().
Ta. That is, the electrode substrate in which a metal electrode layer was formed on the polyester film substrate was mounted in the unwinding chamber, and heated at 215°C in a press sputtering chamber provided between the unwinding T and the reaction chamber.
While heating the substrate, argon gas and/or hydrogen gas was introduced, and 5 to 3
Cleaning is performed by applying high frequency power of 0 W and pre-sputtering the substrate.

Next, a P-type amorphous silicon layer with a thickness of 250 nm was formed on the substrate by glow discharge decomposition in a P-type reaction chamber under a gas atmosphere of 1 torr in which silane gas and ciborane gas at a concentration of 1% of the silane gas were introduced. will be established.

Subsequently, an i-type amorphous silicon layer with a thickness of 5,000 layers is deposited in an i-type reaction chamber using silane gas alone. Next, in an n-type reaction chamber into which silane gas, 1% phosphine gas relative to the silane gas, and hydrogen gas were introduced, an n-type amorphous silicon 1-1 layer containing a microcrystalline layer was formed to a thickness of 200 mm.
A is provided to form a polyester film/An/ss/pin type amorphous silicon laminate. In this way, a predetermined photovoltaic laminate was obtained.

On the other hand, the transparent electrode layer was created as follows.

In other words, the same 100 μm thick polyester film was sputtered as a substrate, installed in the equipment, and heated at 10 torr.
Heat to 50°C while evacuating. Then, argon gas was introduced and a tin-doped indium oxide layer with a thickness of 700 mm was formed on the polyester film by sputtering from a mixed oxide target of indium oxide and tin oxide under an atmosphere of 3X 1O-3 torr. , a predetermined transparent electrode layer was obtained.

As a conductive adhesive layer, a conductive polymer resin in which fine particles of tin oxide were dispersed in a polyester resin binder was coated to a thickness of 1 μm on the indium oxide layer of the transparent electrode layer using a bar code method.

This electrode laminate of transparent electrode layer/conductive resin layer was patterned into 1 cm squares using a YAG laser scribing method to form electrically isolated regions of 10 (IAI).

Next, the photovoltaic laminate and the electrode laminate are stacked so that the amorphous silicon layer and the conductive resin layer are in close contact with each other.
The two laminates were laminated using a laminator device consisting of heated rollers heated to 80° C., and the two laminates were joined to produce a solar cell. The solar cell thus obtained was measured under a fluorescent light of 600 lux, and the conversion efficiency under fluorescent light was 11.5%. Other detailed data are shown in Table 1.

Table 1 Here, the survival rate represents the ratio to the 10 1 cm square solar cells having an open circuit voltage of 0.5 V or more.

The results in Table 1 show that the solar cell of the present invention has sufficient performance and is comparable to conventional examples.

Claims (1)

[Claims] 1. A solar cell comprising a photovoltaic layer made of a semiconductor, and first and second electrode layers, at least one of which is transparent, provided on both sides of the photovoltaic layer, wherein the electrode A solar cell characterized in that at least one of the layers is bonded to the photovoltaic layer by a conductive adhesive layer. 2. The solar cell according to claim 1, wherein the conductive adhesive layer is a conductive polymer resin layer. 3. The solar cell according to claim 2, wherein the conductive polymer resin layer is a polymer resin layer imparted with conductivity by dispersing fine particles of a conductive oxide, metal, or a mixture thereof. 4. A photovoltaic layer made of a semiconductor and first and second electrode layers, at least one of which is transparent, provided on both sides of the photovoltaic layer, and one of the electrode layers is electrically conductive to the photovoltaic layer. In a method for manufacturing a solar cell bonded by a conductive adhesive layer, an electrode to be bonded by a conductive adhesive layer and a photovoltaic layer or a photovoltaic laminate in which a photovoltaic layer is laminated on an electrode layer are prepared in advance. and then bonding the two using a conductive adhesive layer. 5. A claim in which the electrode is bonded to the photovoltaic layer or photovoltaic laminate by a conductive adhesive layer while the photovoltaic layer or photovoltaic laminate and the electrode are transferred by a transfer means. 4. The method for manufacturing a solar cell according to item 4. 6. The photovoltaic layer or the photovoltaic laminate is produced on a long substrate, and the electrode is produced on another long substrate, and the long substrate is transferred and bonded. 5
2. Method for manufacturing a solar cell as described in Section 1.