JPH06151915A - Light generating element, and its manufacture, and manufacturing device used for it - Google Patents

Abstract

PURPOSE:To provide electrode structure which is low in resistance loss and high in conversion efficiency, and low in cost. CONSTITUTION:A mesh electrode body 3 is made in the shape of a lattice net consisting of, for example, longitudinal lines 3a and latitudinal lines 3b by plating process or the like, using a copper material, etc. Since the electrode body 3 is bonded and fixed onto an electrode formation face 4, a conductive adhesive 2 is interposed between, for example, the electrode body 3 and the electrode formation face 4. The adhesive 2 bonds and fix them by thermosetting or the like. The effective adhesive face to the electrode formation face substantially increases and connective by forming the electrode body 3 in net shape, and the adhesion improves, and the adhesive strength can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic element, and more particularly to improvement of an electrode structure, a manufacturing method thereof and a manufacturing apparatus thereof.

[0002]

2. Description of the Related Art Conventionally, when forming an electrode in a photovoltaic device, a low resistance metal is directly attached to an electrode formation surface by using a vacuum evaporation method or a sputtering method, or a conductive resin is applied by an electrode using a screen printing method. It adhered to the forming surface and was fired.

For example, FIG. 9 (a) shows an example of electrode formation using a vacuum deposition method, in which an electrode forming surface 912 of a photovoltaic element 911 is highly exposed through an opening of a metal mask 913. Electron beam 9 emitted from electron gun 915 in vacuum
It comprises the step of depositing and forming the low resistance metal 914 evaporated by the irradiation of 16.

Further, FIG. 9B shows an example of electrode formation by the screen printing method.
21 using the conductive resin 922 as a screen mask 12
3 through the open hole, the electrode forming surface 9 of the photovoltaic element 924
No. 25, and the step of firing the adhered one.

As a method of forming electrodes other than the above, there is a method shown in FIG. 4 (a) described in Japanese Patent Laid-Open No. 3-6867. According to this method, a linear electrode body 45 is attached onto an electrode forming surface 44 of a photovoltaic element 41 via a conductive adhesive 42 formed by dispersing silver spherical fine particles or the like in a resin material such as epoxy. Is pressed and then cured and fixed by heat or the like.

[0006]

However, in the method of forming the electrode of the photovoltaic element by performing vacuum deposition or sputtering of the above metal, it is difficult to form a thick film for making the electrode have a low resistance. There is a problem in that a large amount of energy is required for its formation, resulting in a high cost.

When the electrodes are formed by the screen printing method, a conductive material in which fine particles of silver or copper, which is a conductor, are dispersed in an epoxy resin or polyester resin, which is an insulator, or a polyimide resin is used as an electrode material. Since a resin is used, it is necessary to widen the electrodes or increase the number of electrodes in order to have a large electric resistance and reduce power loss. Therefore, there is a problem that the area occupied by the electrodes on the electrode formation surface increases, the effective area that is the light incident area of the element decreases, and the photocurrent that accompanies this decreases.

Further, in the method shown in FIG. 4A as a method for solving these problems, there is a problem in the following bonding process.

For example, the electrode forming surface 44 of the photovoltaic element 41
And in order to secure the conductivity of the linear metal body 45,
It is necessary to make close contact with the electrode forming surface with good accuracy, but all the pressing force required at the time of this contact will be transmitted to the linear metal body. The thinner the line width of the material, the better, and with the recent screen printing technology, printing of about 50 μm is possible. For example, if the line width of a linear metal body made of copper is 50 μm, its tensile strength is 0. .236 [N] (≈24
[G]), and there is a problem that if the pressing becomes strong, the cutting is performed and the manufacturing process is stopped.

Further, in order to reduce the power generation cost of the photovoltaic element, it is necessary to increase the area of the electrode formation surface. For example, in a photovoltaic element of 30 cm square, the disturbance such as vibration caused by the equipment causes There are problems such as difficulty in adapting to a predetermined position.

In addition, as in the method shown in FIG.
When the adhesive agent 42 is interposed between the electrode body 45 and the electrode forming surface 44, as shown in FIG. 4B, a part of the adhesive agent 42 is partially applied to the electrode due to the pressing force at the time of adhesion. Body 4
5, but since the electrode body 45 is a non-transparent body, the overflow portion 42a diminishes the incident light, and the amount of dimmed light of the photovoltaic element 41 increases. As a result, the conversion efficiency is reduced.

It is an object of the present invention to provide a photovoltaic element having an electrode structure with low resistance loss, high conversion efficiency and low cost, a method for producing the same, and an apparatus for producing the same.

[0013]

The structure of the invention, which is the core of the present invention, is such that an electrode body in which at least a part of the constituent parts formed in a mesh shape is a metal is placed on the electrode formation surface via a conductive adhesive. It is characterized by being adhesively fixed to.

[0014]

The reticulated electrode body is formed in a grid reticulated structure having vertical lines and horizontal lines, for example, and the metal wire portion is made of a copper material. In order to bond and fix the electrode body on the electrode formation surface,
For example, a conductive adhesive is interposed between the electrode body and the electrode forming surface, or a transparent adhesive is applied on the electrode forming surface so as to cover the electrode body. The adhesive is adhered and fixed by thermosetting or the like. By forming the electrode body in a net shape, the effective adhesive surface with respect to the electrode forming surface is substantially increased and cooperates, the adhesion is improved, and the adhesive strength can be increased.

[0015]

1 shows a photovoltaic device 1 according to a first embodiment of the present invention.

The mesh electrode body 3 is made of a copper material and has a thickness of 50.
The vertical lines 3a and the horizontal lines 3b each having a line width of 50 μm and a line width of 50 μm are formed in a grid pattern, and in the present embodiment, they are formed by a plating process. A conductive adhesive 2 is interposed between the electrode body 3 and the electrode forming surface 4, and the conductive adhesive 2 is formed by dispersing adjacent fine silver particles in an epoxy resin. It has a thickness of 10 μm. The conductive adhesive 2 is
The effective adhesive surface to the electrode body 3, that is, the adhesive 2 was applied only to the surface facing the electrode forming surface 4, and after being transferred to the electrode forming surface 4, it was adhesively fixed by thermosetting. By forming the electrode body 3 in a net shape, the effective adhesive surface with respect to the electrode forming surface 4 is substantially increased and cooperates, so that improvement in adhesion and increase in adhesive strength can be realized.

In the description of the above embodiments, the metal mesh formed by plating is used as the electrode body 3. However, other than that, it may be punched by a press or a plain weave metal gauze used for screen printing or the like. Things can also be applied.

The conductive adhesive 2 is not limited to the epoxy type. For example, in the case of a thermosetting resin, a polyester resin, a polyvinyl resin, a polyimide resin, a polyurethane resin, a phenol resin, an acrylic resin, or the like can be used. Further, as the conductive fine particles, copper other than the above-mentioned silver,
A metal oxide (eg, ITO, SnO ₂ ) or the like can also be used. Further, as a means for curing the adhesive 2, there are means such as ultraviolet rays and a two-liquid mixture in addition to the use of heat. In FIG. 1, the cross section of the mesh structure of the electrode body 3 is square, but the cross section is not limited to this and may be, for example, a hemisphere or a circle.

FIG. 3 shows an electrode body relating to the photovoltaic device of the second embodiment. In this embodiment, the thread body of the electrode body 33 has a concave groove 33a. With this configuration,
Since the adhesive can be enclosed in the concave groove 33a in the transfer and adhesion process, there is an advantage that the increase of the light-shielding portion due to the overflow of the adhesive is suppressed.

In the step of providing the reticulated electrode body on the electrode formation surface, a copper adhesive is previously printed on the electrode formation surface by screen printing, and then the reticulated electrode body is placed on the adhesive. Is also possible.

In this case, the conductive adhesive may be applied to the reticulated electrode body in advance, and after the electrode body is placed on the electrode forming surface, it is fixed by soldering with cream solder or the like. It is also possible to do so.

FIG. 2 shows a photovoltaic device 2 according to the third embodiment.
1 is shown.

In this embodiment, the electrode body 23 includes a copper wire 23a which is a vertical wire and a tetron-based transparent fiber 23 which is a horizontal wire.
It is a gauze in which b is knitted in a lattice shape, and the electrode body 23 is bonded and fixed to the electrode forming surface 24 of the photovoltaic element via the conductive adhesive 22. In the case of the present embodiment, a fiber having high transparency is used as the horizontal line 23b, and in the process of formation, while maintaining the same adhesion to the electrode formation surface as in the first embodiment, the incidence of the photovoltaic element A wider aperture ratio for light was realized.

For example, as in the first embodiment, the wire diameter is 5
When the gap is 0 μm and the stitch interval is 2 mm, the aperture ratio in that case is 95%, but in the third embodiment, the transparent fiber 23 is used.
When the light transmittance of b was 90%, the aperture ratio could be improved to 97.6%.

FIGS. 8 (a) and 8 (b) show the arrangement shape of the collecting electrodes when the photovoltaic device according to the above-mentioned embodiment is modularized, and FIG. 8 (a) shows four sides. In the case where the collector electrodes 81a to 81d are provided in FIG.
In the case of having the collector electrodes 81e and 81f on two sides,
The aperture ratio of the module could be improved by the amount of the two sides omitted as compared with FIG.

FIG. 5 shows a first manufacturing process of a photovoltaic element having a mesh electrode body, and FIG. 5 (a) shows a sheet 51 made of a mesh-shaped thin film metal which is press-formed from a roll 51. The process for punching a rectangular electrode body in a plan view by the machine 52 is shown. FIG. 2B shows a mesh electrode body 58 corresponding to the punched portion 51a of FIG. 1A, and the electrode body 58 has a frame 58 on four sides of the peripheral edge.
a is provided. FIG. 7C shows a step of applying a conductive adhesive to the mesh electrode body 58, 53 is a frame for fixing the mesh electrode body 58, 55 is a tray storing the conductive adhesive, Reference numeral 54 is a roller for roll-coating a conductive adhesive. FIG. 6D shows a step of heating the adhesive to bond and fix the adhesive. In order to press the photovoltaic element 59 against the mesh electrode body 58, the flat plate pedestal 56 to which the photovoltaic element 59 is fixed is attached. , Is designed to move up and down. Reference numeral 57 denotes a heater, which heats the entire mesh electrode body 58 fixed to the frame 53 to heat and cure the conductive adhesive interposed between the electrode forming surface and the mesh electrode body.

The conductive adhesive is applied to the mesh electrode body 58 by roll coating here, but it is also possible to apply it by spray coating, dipping, or the like.
It is not limited to this. Although a heater is used as the heating means here, for example, a current may be passed through the mesh electrode body to generate heat. The pedestal 5 for pressing
6 is not limited to the flat plate shape, and may be, for example, a spherical shape or a cylindrical shape.

FIG. 6 shows a second embodiment of the photovoltaic device according to this embodiment.
Shows the manufacturing process of.

In FIG. 1A, reference numeral 61 is a roll formed by mounting reticulated metal bodies constituting reticulated electrode bodies, 62 is a pressure roller, 63 is a roller for roll coating, and 64 is a conductive adhesive reservoir. It is a tray.

FIG. 3A shows a step of applying a conductive adhesive to the mesh metal body. In this step, the conductive adhesive is first attached to one surface side of the mesh metal body.

FIG. 6B shows a step of fixing a part of the reticulated metal body in which the roll 61 is expanded, and an aluminum frame 66 having a pillar 65 is crimped in a sandwich shape on a part of the reticulated metal body. Can be installed with.

FIG. 7C shows a step of pressing the reticulated metal body against the electrode forming surface of the photovoltaic element, and 67 is a pedestal on which the photovoltaic element is mounted. The pressing is performed by moving the pedestal 67 upward with respect to the aluminum frame 66 fixed by the pillars 65.

FIG. 3D shows the heating step of the adhesive, in which the conductive adhesive is hardened and fixed by the heater 68 above the reticulated metal body surrounded by the frame 66.

In this description, the aluminum frame fixing step is performed after the adhesive applying step, but the order of both steps may be reversed. Also, instead of the aluminum frame 66,
A frame made of a material such as iron or stainless steel may be used. Further, although the adhesive is applied by roll coating, spray coating or the like may be used. The shape of the frame is not limited to the rectangular shape.

FIG. 7 shows a series of all steps in the explanation of FIG. 6 described above.

In the figure, 71 is a feed roller, 72 is a roll coat roller, 73 is a tray storing conductive adhesive, 75 is an aluminum frame for fixing mesh metal bodies in a sandwich form, and 74 is the aluminum frame. 75
Is a column provided to fix the. Reference numeral 76 is a base on which a photovoltaic element is mounted, 77 is a heater, and 79 is a press machine. When the press machine 79 is moved downward, the net-like electrode body 78 is cut off along the inner frame shape of the aluminum frame 75 and integrated with the photoelectric element on the pedestal 76.

FIG. 10 shows a photovoltaic device according to the fourth embodiment.

The reticulated electrode body 101 is made of a copper material, and has vertical and horizontal lines with a thickness of 30 μm and a line width of 50 μm formed in a grid pattern with a line spacing of 2 mm, and was produced by a plating process in this embodiment. The mesh electrode body 101 is placed on the electrode forming surface 103 of the photovoltaic element, and the electrode forming surface 103
The surface portion of was covered with the highly transparent adhesive agent 102 together with the electrode body 101.

Here, the transparent adhesive 102 was spray-coated with a thermosetting butyral type paint. The material of the electrode body 101 may be aluminum, silver, gold or the like other than the above-mentioned copper, and the cross-sectional shape of the electrode body 101 may be square, columnar or semi-cylindrical.

Further, as the adhesive 102, a polymer material such as a polyester resin, a polyimide resin, an acrylic resin or the like, as well as a ceramic paint or a metal oxide metal organic paste can be used. Further, as a method of adhesion, in addition to the spray coating, coating, coating with a dispenser, an injection molding machine, or dipping may be used. As the fixing method, in addition to the heating and curing methods, a method using a photo-curing adhesive or an adhesive such as a two-liquid mixture can be adopted.

FIG. 12 shows an example of a manufacturing process of the photovoltaic device according to the fourth embodiment, in which a roll 121 provided with a mesh-shaped thin-film metal sheet body is used to press the machine 1.
A rectangular electrode body 123 is punched out by 22 in a plan view ((a) and (b) in the figure), and a nozzle 124 disposed above a frame 128 fixed via a column 125.
Then, a transparent adhesive is spray-applied toward the electrode formation surface.

FIG. 11 shows a photovoltaic device according to the fifth embodiment. In the present embodiment, the mesh electrode body is a gauze in which a copper wire 111 having a vertical line diameter of 50 μm and a highly transparent tetron-based transparent fiber 112 having a horizontal line diameter of 50 μm are knitted in a lattice shape. Also in the case of this embodiment, the fourth
In the same manner as in Example 1, the reticulated electrode body was placed on the electrode formation surface, and then a butyral-based paint or the like as a transparent adhesive was applied by spray coating. In this embodiment, the horizontal line 2
3b uses a highly transparent fiber, and in the process of formation, while maintaining the same adhesiveness to the electrode formation surface as in the first embodiment, a wider opening for incident light of the photovoltaic element. The rate was achieved.

For example, as in the third embodiment, the wire diameter is 50 μm, the stitch interval is 2 mm, and the transparent fiber 112 is used.
When the light transmittance of the above was 90%, the aperture ratio could be improved to 97.6%. Here, the transparent fiber may be a nylon or polyester type in addition to the Tetron type.

Note that, for example, as shown in FIG. 13, a suitable number of linear electrode bodies 133 are stretched substantially in parallel on the electrode forming surface 131, and the transparent adhesive 132 is provided so as to cover each electrode body 133, respectively.
A method of bonding and fixing using is also conceivable.

In such a method, as shown in FIG. 14, the electrode forming surface 142 is placed on a pedestal 141 which is convex upward with respect to each electrode body 133 ((a) in the same figure), and the pulley 143 is lowered to make a copper wire. 144 (the same figure (b). Next, using a dispenser 146, a transparent adhesive is applied in the wire length direction of the wire 144 (the same figure (c), and then the heater 14
Adhesive fixing of the adhesive is attempted by 6 ((d) of the same figure).

[0046]

According to the present invention, since a low-resistance mesh electrode body is adhered and fixed to the electrode formation surface of the photovoltaic element, it is possible to form an electrode which is lower in cost and less in resistance loss than the conventional one. it can. In this case, if a transparent adhesive is used as the adhesive to adhere to the mesh electrode body so as to cover the electrode body, the electrode body comes into direct contact with the electrode formation surface, so that the resistance can be further reduced. Further, since the electrode body has a mesh shape, the strength against pressure can be further increased in the electrode bonding step, and the adhesion between the electrode body and the electrode formation surface is improved. Therefore, the conditions such as flatness of the electrode formation surface are lenient, and the manufacturing process of the optical semiconductor element can be facilitated and the cost can be reduced by at least that much.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of essential parts showing a configuration of a photovoltaic device according to a first embodiment.

FIG. 2 is a schematic perspective view of an essential part showing a configuration of a photovoltaic device according to a second embodiment.

FIG. 3 is a schematic perspective view of an essential part showing a configuration of a photovoltaic device according to a second embodiment.

FIG. 4 shows an example of the configuration of a conventional photovoltaic device,
(A) is a perspective view of a main part, and (b) is an enlarged plan view of a B part of (a).

FIG. 5 is a schematic perspective view showing a first manufacturing process of the photovoltaic device according to the present invention.

FIG. 6 is a schematic perspective view showing a second manufacturing process of the photovoltaic device according to the present invention.

FIG. 7 is a schematic perspective view showing the overall configuration of a manufacturing apparatus according to the present invention.

FIG. 8 is a schematic perspective view showing the structure of a modular photovoltaic device, where (a) has a frame on four sides,
(B) is a case where a frame is provided on two opposite sides.

9A and 9B are perspective views illustrating a conventional method for forming an electrode body, in which FIG. 9A is a case by vapor deposition, and FIG. 9B is a case by screen printing.

FIG. 10 is a schematic perspective view showing a configuration of a photovoltaic device according to a fourth embodiment.

FIG. 11 is a schematic perspective view showing the structure of a photovoltaic device according to a fifth embodiment.

FIG. 12 is a schematic perspective view showing a step of forming an adhesive application by nozzle spray.

FIG. 13 is a schematic perspective view showing an example of a photovoltaic element formed by adhering linear electrode bodies.

FIG. 14 is a schematic side view showing a manufacturing process of the photovoltaic device shown in FIG.

[Explanation of symbols]

 1 photovoltaic element, 2 conductive adhesive, 3 reticulated electrode body, 3a vertical line, 3b horizontal line, 4 electrode forming surface.

Claims (7)

[Claims] 1. A photovoltaic device, comprising: an electrode body in which at least a part of a mesh-shaped component is made of metal, and the electrode body is adhered and fixed to the electrode formation surface via a conductive adhesive. 2. The photovoltaic element according to claim 1, wherein the electrode body is formed of a metal linear body, a fiber body transparent to sunlight, and a lattice network. 3. The photovoltaic power generation according to claim 1, wherein the conductive adhesive is applied only to at least an effective adhesion surface of the electrode body to the electrode formation surface. element. 4. The photovoltaic element according to any one of claims 1 to 3, wherein the conductive adhesive is made of a material that is transparent to at least excitation light for photovoltaic power generation. . 5. The photovoltaic element according to claim 4, wherein the conductive adhesive is applied so as to cover at least the metal of the electrode body. 6. A step of applying a conductive adhesive to an effective adhesion surface of an electrode body having at least a part of a net-like constituent part made of metal, the electrode body having a predetermined surface on the electrode formation surface. And a step of solidifying the conductive adhesive, and a method of manufacturing a photovoltaic element. 7. A means for holding an electrode body, at least a part of which is a mesh-like constituent part, is made of metal, and a conductive adhesive is applied to at least an effective adhesion surface of the surface of the metal facing the electrode formation surface. An apparatus for manufacturing a photovoltaic element, comprising: a means, a means for adhering the electrode body to a predetermined position on the electrode forming surface, and a means for solidifying the conductive adhesive.