JPH0564871B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application] The present invention relates to a method for manufacturing an amorphous solar cell using an amorphous semiconductor as a photovoltaic layer, and more particularly to a method for manufacturing an amorphous solar cell with high yield and productivity. [Prior art] Amorphous solar cells, which use amorphous silicon as a photovoltaic layer among amorphous semiconductors, can be made uniformly and continuously over a wide area at a low substrate temperature using a glow discharge decomposition method using silane gas, disilane gas, etc. It can be deposited on polymer films, glass, ceramics, etc. as substrates.
Various substrates such as metal foil can be selected, and it is widely researched because it is extremely cost-effective. However, there are the following manufacturing problems. The basic structure of an amorphous silicon (Si) semiconductor solar cell is mainly a laminated structure of a metal electrode layer/amorphous Si semiconductor layer/transparent electrode layer provided on the various substrates mentioned above. Amorphous Si semiconductor layer, transparent electrode layer or transparent electrode layer, amorphous Si
Physical methods such as vacuum evaporation method, sputtering method, glow discharge decomposition method, and light
Each layer is sequentially deposited using a film forming method such as a chemical method such as CVD method. For example, when a metal electrode layer, an amorphous Si semiconductor layer, and a transparent electrode layer are sequentially deposited in this order, when a module is created by patterning solar cells on the same substrate, vapor deposition using a mask is used. , a method of patterning a transparent electrode layer by a sputtering method, a dry etching method using a resist, or a wet etching method has been used. By the way, in the case of patterning using a mask,
Since a metal mask or the like must be brought into direct contact with the surface of the amorphous Si semiconductor layer, there is a problem in that the amorphous Si semiconductor layer itself is easily damaged and the yield is reduced. Furthermore, in order to continuously create wide and long large-area solar cells, a wide and long mask with many openings must be brought into close contact with the substrate and moved accurately. There's a problem. On the other hand, patterning using resist not only easily damages the amorphous Si semiconductor layer itself, but also requires complicated processes such as resist attachment, etching, and resist removal. be. [Object of the Invention] An object of the present invention is to solve the above problems and provide a method for manufacturing an amorphous solar cell with high productivity and high yield. [Structure of the Invention] The above-mentioned object is achieved by the following present invention. That is, the present invention provides a method for manufacturing an amorphous solar cell using the aforementioned amorphous semiconductor as a photovoltaic layer, including the steps of: (a) forming an electrode layer on a first substrate; (b) applying a photovoltaic force to the electrode layer; laminating layers to form an intermediate laminate; c laminating an electrode layer on a second substrate to form an electrode laminate; d laminating a photovoltaic layer of the intermediate laminate and/or an electrode laminate a step of forming a conductive adhesive layer on the electrode layer, e a step of overlapping the intermediate laminate and the electrode laminate so that the photovoltaic layer and the electrode layer face each other, and adhering and fixing them with the conductive adhesive layer; In this case, the first and second substrates are flexible elongated substrates, and the substrates are transported in a roll between steps that are not executed continuously, and the roll is rewound between steps that are executed continuously. continuous processing,
This method of manufacturing an amorphous solar cell is characterized in that the solar cell is then wound into a roll, realizing a highly productive process. The present invention described above is based on the conventional knowledge that in order to obtain a good electrical connection, it is essential to form an electrode layer directly on the amorphous Si semiconductor layer of the photovoltaic layer by a film forming method or the like. However, by adhering a separately prepared electrode sheet onto the amorphous Si semiconductor layer using a conductive adhesive, it was surprisingly possible to create a solar cell with performance comparable to conventional directly laminated solar cells. This was done after discovering what could be achieved. From the above-described configuration, the present invention has the following various effects. In other words, since the photovoltaic layer and one 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 one 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, and wide and long electrode layers can be formed. Continuation is easy when manufacturing large area solar cells. In addition, when patterning the electrode layer, it can be easily formed using various methods such as laser scribing, which was difficult to use in the past because it would damage the amorphous Si semiconductor layer, and mask evaporation. Battery patterns can also be easily created. 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, By imparting durability to each substrate, solar cells in their final form can be formed continuously. The details of the present invention will be explained below. FIG. 1 is an overall block diagram of the present invention. As shown, an electrode layer 12 is formed on a substrate 11 in step a. Next, in step b, a photovoltaic layer 13, which will be described later, made of an amorphous semiconductor is laminated to form an intermediate laminate 10. On the other hand, an electrode layer 22 is laminated on the other substrate 21 in step c,
Electrode stack 20 is formed. As is clear from the figure, step c can be performed completely independently of step a and step b, both temporally and spatially. By the way, the above-mentioned substrate 1 located on the light irradiation side
1 and 21 and the electrode layers 12 and 22, transparent substrates and transparent electrodes, which will be described later, are applied. In step d, the photovoltaic layer 13 of the intermediate laminate 10 is
A conductive adhesive layer 31 is formed on and/or on the electrode layer 22 of the electrode stack 20 . Various types of adhesive layers described below can be applied to the adhesive layer 31. Next, in step e, the intermediate laminate 10 and the electrode laminate 20 are overlapped and fixed by adhesive layer 31 to form an amorphous solar cell 30. Incidentally, from the viewpoint of productivity, a continuous process method is preferably applied to each of the above-mentioned steps a to e. Then, the substrates 11 and 21 are rolled up into rolls as flexible long substrates, and transported between each step, and at each step, the rolls are unwound and processed, and then wound up again into the rolls, which improves productivity.
Very advantageous in terms of quality. Incidentally, each of the above-mentioned steps a to e may be performed as an independent device for each step, or a plurality of steps such as step a and step b, or step c and step d, etc. may be continuously processed within one device. It's okay. In the latter case, it is advantageous in terms of equipment, productivity, and quality. Furthermore, if time alignment of each process is achieved, all steps can be processed as a series of continuous processes. If patterning of the solar cell is required, for example, if a laser scribe method is used, a patterning step can be inserted after steps b, c, or d, and if a mask method is used, the necessary processing can be done by masking. It is sufficient to carry out processing according to the patterning method. Each configuration will be explained in detail below. The amorphous silicon semiconductor layer of the photovoltaic layer of the present invention can be deposited using known methods such as glow discharge method, sputtering method, ion plating method, and ion cluster beam method. For example, in the case of the glow discharge method, a three-chamber separated amorphous Si deposition apparatus similar to that disclosed in JP-A No. 59-34668 is used, and silane (SiH ₄ ) and higher-order silane gas are added in a vacuum chamber at 0.01 to Introduce the pressure to 10torr,
A high frequency power of 13.56 MHz is supplied, and an amorphous Si semiconductor layer which is a decomposition product of the gas is formed by glow discharge decomposition. In order to control the P-type or N-type electrical conductivity type of the amorphous Si layer, a gas such as ciborane (B ₂ H ₆ ), phosphine (PH ₃ ), or arsine (AsH ₃ ) is deposited specifically for each type. Introduce an appropriate amount into the room. In addition, in order to control the optical forbidden band width of the amorphous Si semiconductor layer, third component elements such as C, Ge, Sn, N, and F can be introduced, but in that case,
For example, hydrocarbon gas, GeH ₄ , SnH ₄ , NH ₃ ,
It can be used by mixing SiF ₄ gas etc. with silane gas. Alternatively, a portion of the microcrystalline layer may be mixed into the amorphous silicon layer by increasing the input high-frequency power.
In addition to Pin junction, the structure of the photovoltaic layer is Pin/
A tandem structure of Pin or Pin/Pin/Pin can also be used. For the electrode layer, in the case of a normal electrode layer mainly made of metal, Al, Ag, Au, Cu, Pt, Ni, Cr, Fe,
Single-layer and/or multi-layer laminated films of single metals such as Mo, W, Ti, and Co and/or alloy metal layers thereof are applied, and if necessary, electrode layers formed by laminating transparent conductive layers are also applied. In addition, 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. The metal electrode layer may of course be a metal plate itself, or the substrate on which the electrode layer is deposited may be a polymer film, ceramic, glass, or a metal plate or metal foil subjected to an insulating treatment. When the electrode layer is a transparent electrode layer, conductive oxides such as indium oxide, tin oxide, cadmium stannate, and titanium oxide, thin metal films such as Au, Pt, and Pd,
A conductive laminate or the like is used, in which a thin layer mainly composed of Ag is laminated with a conductive oxide layer in the shape of a sandwich. These transparent electrode layers can be formed by known methods such as vacuum evaporation and sputtering.
Surface resistance less than 10000Ω/□, preferably 1000
It is desirable to have a surface resistance of Ω/□ or less and a visible light transmittance of 50% or more. 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 transparent material such as a polymer film, a polymer resin plate, or glass is used. The conductive adhesive layer of the present invention contains tin oxide, indium oxide, titanium oxide, etc. in a polymer resin for a binder such as polyester resin, acrylic resin, polyvinyl resin, epoxy resin, polyurethane resin, silicone resin, etc. A dispersed conductive polymer resin adhesive in which oxide conductive fine particles are dispersed is used. 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. From the viewpoint of adhesive strength, durability, etc., a conductive polymer resin, especially a dispersed conductive polymer resin, is preferable, and from the viewpoint of electrical resistance, a thin layer of a low melting point metal is preferable, and the selection is made depending on the application. These conductive polymer resins are applied to the surface of the electrode layer or amorphous semiconductor layer to be bonded using a method such as a spinner method, a barcode method, a doctor blade method, or a screen printing method. In order to reduce damage to the amorphous semiconductor layer, it is preferable to apply it to the surface of the electrode layer. In order for this conductive adhesive layer to play the role of transmitting the photocurrent generated in the amorphous semiconductor photovoltaic layer to the electrode layer without loss, it is desirable that the conductive adhesive layer has a resistivity of 10 ⁶ cmΩ or less.
The thickness of the adhesive layer is not particularly limited, but it must be determined experimentally as it is related to many factors such as adhesive strength, durability, electrical resistance, and optical transparency, but is usually 0.01.
It is selected in the range of ~10μ. Further, the electrically conductive adhesive layer can also be divided into electrically conductive regions by patterning by laser scribing, etching, etc., or patterned coating by screen printing. Laminating the electrode layer provided with the conductive adhesive layer and the amorphous semiconductor layer,
Further, when each layer is patterned, the amorphous solar cell of the present invention can be formed by appropriately aligning each pattern and laminating. The present invention will be explained below with reference to Examples. [Example] A long 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.
While unwinding this roll of polyester film, an aluminum layer is placed on top of it as a metal electrode layer.
0.4μm thick with an additional 100Å stainless steel layer
The film was deposited continuously using a continuous sputtering device to a thickness of 100 mL, and then wound onto a roll again. An amorphous silicon layer as an amorphous semiconductor layer was formed on the metal electrode using an internal electrode type three-chamber separation type high frequency (13.56MHz) glow discharge device similar to that disclosed in JP-A-59-34668. It was provided on the layer as follows. That is, a roll of an electrode substrate in which a metal electrode layer was formed on the polyester film substrate was placed in an unwinding chamber, and the substrate was heated to 215° C. in a press spattering chamber provided between the unwinding chamber and the reaction chamber. Argon gas and/or hydrogen gas is introduced and high frequency power of 5 to 30 W is applied in each gas atmosphere of 1.0 torr, and the substrate is pre-sputtered and cleaned. Next, a P-type amorphous silicon layer with a thickness of 250 Å is 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% relative to the silane gas are introduced. . Subsequently, an i-type amorphous silicon layer with a thickness of 5000 Å is deposited in an i-type reaction chamber using silane gas alone. Next, an n-type amorphous silicon layer containing a microcrystalline layer was formed to a thickness of 200 Å in an n-type reaction chamber into which silane gas, 1% phosphine gas relative to the silane gas, and hydrogen gas were introduced.
An intermediate laminate made of Al/ss/pin type amorphous silicon is wound into a roll in a winding chamber. In this way, a predetermined photovoltaic laminate roll was obtained. On the other hand, the transparent electrode layer was created as follows.
That is, using the same 100 μm thick polyester film as a substrate, the roll is mounted in a sputtering device and heated to 50° C. while being evacuated to 10 ⁻⁵ torr.
Thereafter, a 700 Å thick tin-doped indium oxide layer was formed on the polyester film by sputtering from a mixed oxide target of indium oxide and tin oxide under an atmosphere of 3×10 ^-3 torr by introducing argon gas. A predetermined transparent electrode layer was laminated to form an electrode laminate, which was then wound to obtain a roll. While unwinding the roll of this electrode laminate, a conductive polymer resin in which tin oxide fine particles are dispersed in a polyester resin binder is applied as a conductive adhesive layer to a thickness of 1 μm using a bar coating method to form the indium oxide layer of the transparent electrode layer. It was continuously coated on top and wound up again to form a roll. While unwinding each roll of the electrode laminate of the transparent electrode layer/conductive resin layer and the photovoltaic laminate described above, each roll was
It was patterned into cm squares to form electrically isolated small areas, and then wound again to form a roll. Next, while unwinding both the rolls of the photovoltaic laminate and the electrode laminate divided into small areas, the amorphous silicon layer and conductive resin layer are overlapped so that they are in close contact with each other, and heated to 180°C. The two laminates were laminated using a laminator device including heated rollers, and the two laminates were joined to produce a solar cell.
The small-area solar cells obtained in this way are
The conversion efficiency under fluorescent light was 11.5% when measured under 600 lux fluorescent light. Other detailed data are shown in Table 1.

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

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the flow of the present invention. 10: Intermediate laminate, 20: Electrode laminate, 30:
Amorphous solar cells.

Claims (1)

[Claims] 1. A method for manufacturing an amorphous solar cell using an amorphous semiconductor as a photovoltaic layer, comprising: (a) forming an electrode layer on a first substrate; and (b) forming an electrode layer on a first substrate. (c) laminating an electrode layer on a second substrate to form an electrode stack; and (d) forming an intermediate stack. (e) forming a conductive adhesive layer on the photovoltaic layer of the intermediate laminate and/or the electrode layer of the electrode laminate; and (e) adhesively fixing the electrode laminate so that the electrode layer overlaps the photovoltaic layer of the intermediate laminate. The first and second substrates are flexible elongated substrates, and the substrates are rolled and transported between steps that are not executed continuously, and are transferred between steps that are not executed continuously. A method for producing an amorphous solar cell, comprising continuous processing while unwinding the roll in between, and then winding it into a roll. 2. The method of manufacturing an amorphous solar cell according to claim 1, wherein the first and second substrates are polymer films. 3. Claim 1 or 2, wherein the conductive adhesive layer is a conductive polymer resin layer coated with the conductive adhesive layer.
1. Method for manufacturing an amorphous solar cell as described in Section 1. 4 The conductive polymer resin layer comprises a conductive oxide,
4. The method for manufacturing an amorphous solar cell according to claim 3, wherein the polymer resin layer is made of a polymer resin layer in which conductivity is imparted by dispersing fine particles of a metal or a mixture thereof. 5 The amorphous semiconductor contains Si and H as main components,
If necessary, suitable amounts of C, Ge, Sn, N, and F are added to select the forbidden band width, and non-containing materials doped with trace amounts of B, P, and As to control the electrical conductivity type. Claim 1, which is a crystalline silicon layer
The method for manufacturing an amorphous solar cell according to item 2, item 3, or item 4.