JP2002353487A - Solar cell module and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell module that has a small amount of wiring loss, and a mechanically strong configuration in a configuration having a power conversion circuit. SOLUTION: In the solar cell module having a thin-film solar cell with a photoelectric conversion layer 102 formed on a conductive substrate 101, and a power conversion circuit for converting power outputted from the thin-film solar cell, an electronic component 301 in the power conversion circuit is packaged to electric wiring 203 provided on the conductive substrate 101, where the photoelectric conversion layer is formed via an insulation layer 201.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell module and a method for manufacturing the module, and more particularly, to a thin film solar cell having a photoelectric conversion layer formed on a conductive substrate, and power output from the solar cell. The present invention relates to a solar cell module provided with a power conversion circuit for converting a voltage and a method of manufacturing the module.

[0002]

2. Description of the Related Art In recent years, problems such as global warming due to the emission of carbon dioxide and the like accompanying the use of fossil fuels, accidents at nuclear power plants and radioactive contamination by radioactive waste have become serious.
Interest in the global environment and energy is growing. Under such circumstances, solar power generation using sunlight as light energy as an inexhaustible and clean energy source is expected around the world.

In order to reduce the cost of solar cell modules and to develop applications, so-called AC modules in which a small-sized power conversion circuit and a solar cell module are integrated have been developed. For example, Japanese Patent Application Laid-Open No. 9-271179 discloses such an AC module.

FIG. 6 is a diagram showing a typical configuration example of the AC module described in the publication. The power conversion circuit 4
It is mechanically fixed to the back surface of the solar cell module 1, and is electrically connected to the solar cell module 1 via the output terminal box 2 and the DC connection cable 3.
The output of the power conversion circuit 4 is connected to a commercial power system through an output cable 5 and a connector 6.

Further, as an advanced form of the AC module, an "AC cell" in which one power conversion circuit is attached to one cell has been studied, and is described in, for example, US Pat. No. 5,660,643. Have been.

[0006]

However, the above-described prior art has the following problems. The solar cell module used for the AC module is a general glass superstrate module with an aluminum frame, which is not optimized for the AC module and has a high cost.

Further, since the connection method between the power conversion circuit 4 and the solar cell module 1 is a normal wiring using the DC connection cable 3, the wiring cost is high. In addition, direct mounting to an output terminal box as described in JP-A-9-271179 may weaken mechanically.

[0008] In the case of the AC cell, when connecting the power conversion circuit and the solar cell, a connection method with less wiring loss and a robust fixing method to the cell are not disclosed.

The present invention has been made in view of the above circumstances, and in a configuration having a power conversion circuit, a solar cell module having a small wiring loss and a mechanically robust configuration, and a method of manufacturing the module. The purpose is to provide.

[0010]

In order to achieve the above object, a solar cell module according to one embodiment of the present invention comprises: a thin film solar cell having a photoelectric conversion layer formed on a conductive substrate; A power conversion circuit for converting power output from the thin-film solar cell, comprising: a power conversion circuit, wherein the power conversion circuit is connected to an electrical wiring provided on the conductive substrate via an insulating layer. It is characterized by being composed of mounted electronic components.

A solar cell module according to another embodiment of the present invention that achieves the above object has a thin-film solar cell having a photoelectric conversion layer formed on a conductive substrate, and an output from the thin-film solar cell. And a power conversion circuit for converting power, wherein the power conversion circuit comprises an electronic component mounted on one surface of a circuit board having a conductive layer and an insulating layer on each surface. The conductive substrate and the other surface of the circuit board are fixed with a conductive material.

That is, in the present invention, a thin-film solar cell having a photoelectric conversion layer formed on a conductive substrate, a power conversion circuit for converting power output from the thin-film solar cell,
In the solar cell module provided with, the electronic components of the power conversion circuit is mounted on an electric wiring provided via an insulating layer on a conductive substrate on which a photoelectric conversion layer is formed, or a conductive layer is provided on each surface. And a circuit board having an insulating layer, and the conductive substrate and the other surface of the circuit board are fixed with a conductive material.

[0013] In this case, since the thin-film solar cell and the power conversion circuit are directly connected without using a connecting means such as a cable, the conductive loss is reduced and the connecting means is not required, so that the cost can be reduced. .

Further, since the solar cell and the power conversion circuit are integrally formed, the structure is mechanically strong, the mechanical strength is increased, and the durability and maintainability are improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a solar cell module according to the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIG. 1 is a cross-sectional view showing a configuration example of a solar cell module having a power conversion function according to the present invention. Hereinafter, constituent materials and manufacturing methods will be described for each component.

[Photovoltaic Device] A photovoltaic device having three layers of photoelectric conversion layers containing amorphous silicon and having a collecting electrode and an extraction electrode is manufactured. A method for manufacturing such a photovoltaic element is disclosed in a publication of the same applicant as the present application.
Japanese Patent Application Laid-Open No. 6-139439 describes details of the application of a current collecting electrode such as 21494,
It is well known. In the present invention, the method of producing the photovoltaic element itself is not an essential part, and will be briefly described below.

(1) A stainless steel plate to be the conductive substrate 101 is prepared. Here, the one having a thickness of 0.125 mm was used. In addition, as the conductive substrate, a substrate in which an insulating substrate is provided with a conductive layer, such as a substrate in which a transparent conductive film is provided on a glass substrate or a substrate in which a metal is deposited on a polyimide film, can be used. When such a material is used, an insulating substrate portion of a substrate can be used as a part of an insulating layer 201 described later.

(2) A thin film of aluminum and zinc oxide is applied as a back reflection layer to a thin stainless steel plate by a method such as sputtering. (3) A semiconductor layer containing amorphous silicon and amorphous germanium is repeatedly generated three times in order of an n-layer, an i-layer, and a p-layer by a CVD method to form a photoelectric conversion layer 102 having three sets of pin junctions. create.

(4) A tin oxide-indium layer (not shown) is provided as a transparent conductive layer.

Next, a current collecting electrode portion is formed through the following steps.

(5) Cut the cell into a suitable size. In this embodiment, it was cut into 356 mm × 239 mm.

(6) In order to remove the effect of a partial short circuit at the end of the metal substrate, a part of the photoelectric conversion layer at the end of the cell is removed by chemical etching.

(7) Attach the insulating tape 104 to the end. A positive electrode tab 105 made of tin-plated copper foil is attached thereon.

(8) A current collecting electrode 103 made of a copper wire with a conductive adhesive is attached to the transparent conductive layer and the positive electrode tab 105.

Thus, the solar cell is completed. The optimum operating voltage and the optimum operating current of the solar cell in the standard measurement state (spectrum AM 1.5, irradiance 1.0 kW / m ² , cell temperature 25 °) are 1.4 V and 4.6, respectively.
A.

In carrying out the present invention, in particular, one cell
In the case where a plurality of power conversion circuits are provided, the solar cell element is preferably a stacked type as used in the present embodiment.
This is because the output voltage of unstacked solar cells is only 0.5 V at most, and it is generally difficult to operate an electronic circuit at this voltage. If three layers are stacked as in this embodiment, an operating voltage of 1.4 V or more can be obtained, which corresponds to the electromotive force of one dry battery. Electronic components that operate in such a voltage range are easily available and have features that circuit design is very easy.

Further, the solar cell used in the present embodiment is preferably a thin-film large-area type which is easy to increase the mass production effect. In this case, there is a possibility that the cost can be significantly reduced in the future.

[Insulating Layer] Next, the insulating layer 201 was formed using a polymer coating resin. There are many known coating resins such as an epoxy resin resin, a phenol resin resin, and a silicone resin resin. Here, a silicon resin-based resin used for electrical insulation was used. In the present embodiment, the resin is applied to a necessary portion with a brush, and cured with an infrared heater to obtain the resin shown in FIG.
Was formed as shown in FIG.

As another means for realizing this, a resin can be applied by using a dipping method or a coater method.
The thickness needs to be selected according to the output voltage of the power conversion circuit and the type of resin, but a thickness that allows sufficient insulation to be maintained with respect to the operating voltage is required. It has been found that if many resins have a thickness of about 1 mm, a withstand voltage of 200 V or more can be easily achieved. Here, the output voltage was very low at 5 V, so the thickness was set to 100 μm. A paint-based material having such a thickness can be used.

[Conductive layer] As the conductive layer, electroless plating,
A metal film formed by a method such as a high-conductivity paste for electric wiring or a vapor-deposited film can be used. In the present embodiment, a copper layer is provided at a necessary portion by electroless plating, and then the unnecessary portion is removed by chemical etching to selectively provide a conductive layer. As a result, the positive electrode side conductive layer 202 and the wiring conductive layer 20 are formed.
3. The negative electrode side conductive layer 204 was formed.

As can be seen from FIG. 1, since both the conductive layer and the insulating layer need to be turned around the back surface of the solar cell, a method of forming a relatively thin conductive layer such as evaporation is employed. Must be very careful not to cause a break in the wraparound area. Also, the negative electrode side conductive layer 2
It is important that the connection between the substrate 04 and the metal substrate 101 be sufficiently cured so as not to come off. In addition, the use of a high-conductivity paste for electric wiring allows a conductive layer for wiring to be directly formed without the above-described chemical etching, which is also a preferred method for implementing the present invention.

Since electronic components are to be mounted on the conductive layer by soldering or the like, the conductive layer and the insulating layer 20 are formed.
First, it is necessary to select a material that can withstand heat and other stresses during the mounting operation.

In the present embodiment, the component mounting surface is opposite to the light receiving surface. In this case, the component is not exposed to direct sunlight, which is advantageous in improving durability.
On the other hand, when the component surface and the light receiving surface are the same, a remarkable effect can be expected in terms of productivity and ease of installation.

[Configuration of Power Conversion Circuit] [Circuit System] FIG. 4 is a circuit diagram of the power conversion circuit used in the present embodiment. The present embodiment uses a so-called non-insulated boost chopper circuit, which is configured using a dedicated IC 401 (MAX1709, manufactured by Maxim Corporation) having a built-in control circuit. The use of such a dedicated IC is advantageous in assembling because the number of parts can be reduced. For example, in this embodiment, there are only nine external components other than the IC 401.

The circuit system is not limited to the boost chopper system. Naturally, a configuration using discrete components is also possible, and the invention is not limited to the step-up chopper, but may be a step-down chopper or an inverter circuit. What is necessary is just to select a circuit system suitably according to what is needed as an output. The input rating in this embodiment is DC1.2
V, 4 A (operable input voltage range 0.7 V to 5 V), and the output was DC 5 V, 0.7 A.

[Electronic Components] Each component of the circuit shown in FIG. 4 is preferably a surface mount type (so-called SMD type) as indicated by 301 in FIG. This is because, in practicing the present invention, it is difficult to solder a lead wire through a hole as in a normal printed circuit board. This does not preclude the use of components with leads, but in that case, it is necessary to bend the leads and solder them on the wiring conductor surface, which weakens the mounting strength.

In recent years, almost all types of electronic components are compatible with surface mounting, and it is desirable to select such components when implementing the present invention. Also,
In order to reduce the component size, recently, there is a "bare chip component" in which the semiconductor element is exposed without the outer mold resin coating, and using the bare chip component makes the power conversion circuit thinner. It becomes possible.

Incidentally, specific examples of the components shown in FIG. 4 are as follows: D1: Schottky barrier diode, 30V, 10A L1: 1 μH, maximum rated voltage 9V C1, C2: 330μF, 10WV, tantalum electrolytic capacitor C3, C4, C5: 0.22 μF, 16 WV, multilayer ceramic capacitor R1: 2Ω, ４ W R2: 330 kΩ, ８ W

[Component mounting] The mounting of the electronic component on the conductive layer is performed as follows.
What is necessary is just to carry out similarly to normal electrical product assembly. For example, a surface mount component is attached to the conductive layer with a solder paste, and soldering is performed by a reflow method. In this embodiment,
Soldering work was performed by such a reflow method. In addition, various other methods such as manual mounting soldering can be adopted.

Finally, the conductive layer and the power conversion circuit were sealed with a publicly known and used semiconductor sealing epoxy resin. This fact is not essential in the practice of the present invention, but is a necessary measure for improving the durability when used outdoors.

A solar cell module having a power conversion function was manufactured as described above. This system is installed outdoors to receive sunlight (insolation intensity 0.8 kW / m
^When the output voltage was checked, 5 V was output, and it was confirmed that the circuit operated normally.

As described in detail above, according to the present embodiment, the electrodes of the solar cell and the input electrodes of the power conversion circuit are directly connected, and the wiring can be made with the shortest distance. As a result, the loss can be reduced and the amount of power generation can be increased. Also, an intermediate connection cable conventionally used for connection is not required. Further, in the present embodiment, a printed circuit board for the power conversion circuit is not required, so that a large cost reduction can be expected as a whole when mass production is performed.

[Second Embodiment] Hereinafter, a second embodiment of the solar cell module according to the present invention will be described.
In the following description, the same parts as those in the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted, and the description will focus on characteristic parts of the present embodiment that are different from the first embodiment.

In this embodiment, the power conversion circuit is formed on a printed circuit board. FIG. 2 is a cross-sectional view showing the configuration of the present embodiment. Hereinafter, constituent materials and manufacturing methods will be described for each component.

[Photovoltaic Element] The structure of the solar cell element is almost the same as that of the first embodiment. The present embodiment is characterized in that the insulating tape 104 and the tin-plated copper tab 105 used in the first embodiment are made wide, and these are turned around to the back surface to form the insulating layer 201a and the conductive layer 201. is there.

[Power Conversion Circuit] Next, a circuit board 207 having copper foil on both sides is prepared, a circuit board is formed by a known process such as etching, and an electronic component 301 is mounted to configure a power conversion circuit. The circuit system is the same as that of the first embodiment. As the substrate, a flexible printed substrate based on a polyimide film was used. If the substrate is used, the entire thickness can be reduced, and the entire solar cell module can have flexibility.

Here, the surface on which the components are not mounted is used as the input electrode 205 as copper foil over the entire surface. Input electrode 204
And a part 204 of the copper foil on the circuit surface
Electrically connected by In the present embodiment, a so-called flexible film substrate is used. However, a glass epoxy substrate having a multilayer copper foil capable of forming a more complicated circuit may be used, and may be determined as needed.
For example, a multi-layer board would be suitable for a circuit having a large number of components and a complicated circuit such as an interconnection inverter. In many cases, the use of a substrate having such a multilayer structure is also desirable from the viewpoint of EMC (electromagnetic compatibility).

[Connection between Power Conversion Circuit and Solar Cell] The electrical connection and fixation between the metal substrate 101 and the input electrode 205 were performed using a commercially available epoxy-based conductive paste. If the adhesive strength is insufficient, the area to be coated with the conductive paste is slightly reduced, and an adhesive with strong adhesive strength to the metal (for example, an epoxy-based adhesive) can be used to firmly adhere to the area. it can. Alternatively, a method of temporarily bonding using a solder paste and then fusing and fixing in a reflow furnace may be used. Since the positive electrode-side conductive layer 202 is a tab electrode as described above, an electronic component is mounted so as to extend over the tab electrode and the wiring conductor layer 203 on the circuit board side, and is also connected to the positive electrode side.

Finally, the device was sealed with a silicone resin-based weather-resistant resin in the same manner as in the first embodiment. The silicone resin used here is softer than the epoxy resin,
Even in a sealed state, the entire device can have flexibility.

According to the solar cell module of the present embodiment configured as described above, the power conversion circuit portion can be manufactured by the existing electric product assembly process, so that newly required capital investment is small. I'm done. In addition, since the power conversion circuit and the solar cell are connected with the shortest wiring as in the first embodiment, the loss is small, and an intermediate connection cable as in the related art is not required. Further, since a flexible resin substrate is used as a substrate of the power conversion circuit, the entire device can have flexibility.

[Third Embodiment] Hereinafter, a third embodiment of the solar cell module according to the present invention will be described.
In the following description, the same parts as those in the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted, and the description will focus on characteristic parts of the present embodiment that are different from the first embodiment.

In this embodiment, an example in which a power conversion circuit is formed on the same surface as the light receiving surface will be described. FIG. 5 is a top view showing a configuration example according to the present embodiment, and FIG.
FIG. 4 shows a cross-sectional view along A ′. Hereinafter, constituent materials and manufacturing methods will be described for each component.

[Photovoltaic Element] The photovoltaic element is formed in substantially the same manner as in the first embodiment. The difference is that the removal area of the photovoltaic element is increased by chemical etching in order to mount the power conversion circuit, and the collecting electrode 10
3 is directly connected to the positive electrode side conductive layer 202 of the circuit board 207 by heat fusion. In order to directly connect the current collecting electrodes as described above, it is necessary to connect the circuit board 207 to the conductive substrate 101 via the negative electrode side conductive layer 205 before the step of attaching the current collecting electrodes 103. is there.

[Power Conversion Circuit] The circuit used in this embodiment is the same as that of the first embodiment, and a glass epoxy substrate is used as the substrate. Components were mounted on this board using existing assembly equipment to form a power conversion circuit. Similarly to the first embodiment, the copper foil on the side opposite to the component mounting surface is not etched, and can be used as an electrode 205 for connection to the metal substrate 101.

[Connection between Power Conversion Circuit and Solar Cell] The connection between the power conversion circuit and the solar cell
Must be performed prior to the mounting process. Metal substrate 1
For electrical connection and fixation of the input electrode 205 and the input electrode 205, a method of temporarily bonding using a solder paste and then melting and fixing in a reflow furnace was adopted. Finally, the device was sealed with a silicone resin-based weather-resistant resin as in the second embodiment.

According to the solar cell module of the present embodiment configured as described above, since the electronic component mounting surface and the light receiving surface of the solar cell are all the same, the light receiving area with respect to the surface area of the solar cell is reduced. However, it is very suitable for an assembling operation using a belt conveyor or the like, and the productivity becomes very good. Also, since the back side can be flat, it can be easily installed on a concrete wall or the like by using an adhesive for construction or the like. Further, as shown in FIG. 5, since the output cable is also taken out on the front side, even in the case where the output cable is installed on a concrete wall as described above, there is a practically very advantageous feature that the connection work is extremely simple.

When a solar cell array is formed using the solar cell module of this embodiment, there is an advantage that the conductive substrate portion can be effectively used as a parallel wiring member. In other words, by electrically connecting the conductive substrates to the same potential as the ground, it is possible to use the metal gantry as it is for the parallel wiring portion and to wire the output of the power conversion circuit in parallel with a single wire, Compared with the conventional parallel wiring using two electric wires, the amount of electric wires used and the labor required for installation can be greatly reduced.

In the above-described embodiment, the end of the metal substrate is used for the power conversion circuit. However, other arrangements can be adopted. For example, if the photoelectric conversion layer at the center of the cell is removed in a circular shape and a current collecting electrode is wired toward the circular portion, the current collecting loss can be reduced.

[Other Embodiments] The present invention may be applied to a system including a plurality of devices or to an apparatus including a single device.

For example, a plurality of solar cell modules according to the present invention can be connected to form a solar cell array or a solar power generation system.

[0062]

As described in detail above, according to the present invention, since the thin-film solar cell and the power conversion circuit are directly connected without using a connecting means such as a cable, the conductive loss is reduced and the connecting means is reduced. Becomes unnecessary, and the cost can be reduced.

Further, since the solar cell and the power conversion circuit are integrally formed, the structure is mechanically strong, the mechanical strength is increased, and the durability and maintainability are improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a first embodiment of a solar cell module of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a second embodiment of the solar cell module of the present invention.

FIG. 3 is a cross-sectional view taken along line AA ′ of FIG. 5 showing a configuration of a third embodiment of the solar cell module of the present invention.

FIG. 4 is a circuit diagram showing a configuration example of a power conversion circuit of the solar cell module of FIG.

FIG. 5 is a top view showing the configuration of a third embodiment of the solar cell module of the present invention.

FIG. 6 is a schematic diagram showing an example of a conventional power conversion circuit integrated solar cell module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solar cell module 2 Output terminal box 3 Connection cable with power conversion circuit 4 Small power conversion circuit 5 Output cable 6 Output connector 101 Conductive substrate 102 Photoelectric conversion layer 103 Current collecting electrode 104 Insulating tape 105 Metal tab (positive electrode) 201 Reference Signs List 201a Insulating layer 201b Insulating layer of printed circuit board 202 Positive side conductive layer 203 Wiring conductive layer 204 Negative side conductive layer 205 Planar input electrode 206 Connection through hole 207 Printed circuit board 301 Electronic component

Claims (17)

[Claims] 1. A solar cell module comprising: a thin-film solar cell having a photoelectric conversion layer formed on a conductive substrate; and a power conversion circuit for converting power output from the thin-film solar cell. A solar cell module, wherein the power conversion circuit comprises an electronic component mounted on electric wiring provided on the conductive substrate via an insulating layer. 2. A solar cell module, comprising: a thin-film solar cell having a photoelectric conversion layer formed on a conductive substrate; and a power conversion circuit for converting power output from the thin-film solar cell. Wherein the power conversion circuit comprises an electronic component mounted on one surface of a circuit board having a conductive layer and an insulating layer on each surface, wherein the conductive substrate and the other surface of the circuit board are made of a conductive material. A solar cell module, which is fixed by: 3. The solar cell module according to claim 1, wherein the electronic component is mounted on a side opposite to the photoelectric conversion layer. 4. The solar cell module according to claim 1, wherein the electronic component is mounted on the same side as the photoelectric conversion layer. 5. The solar cell module according to claim 1, wherein the electronic component is a surface mount component. 6. The solar cell module according to claim 5, wherein said surface mount component includes a bare chip type semiconductor component. 7. The solar cell module according to claim 1, wherein a plurality of the photoelectric conversion layers are stacked. 8. The solar cell module according to claim 1, wherein the power conversion circuit is provided for each element of the thin-film solar cell. 9. A solar cell array comprising a plurality of the solar cell modules according to claim 1. Description: 10. A thin-film solar cell having a photoelectric conversion layer,
A method for manufacturing a solar cell module, comprising: a power conversion circuit that converts power output from the thin-film solar cell, comprising: forming the photoelectric conversion layer on a conductive substrate by a semiconductor manufacturing process; A method for manufacturing a solar cell module, comprising: providing electric wiring on a substrate via an insulating layer; and mounting electronic components of the power conversion circuit on the electric wiring. 11. A thin-film solar cell having a photoelectric conversion layer,
A power conversion circuit for converting the power output from the thin-film solar cell, comprising: a photoelectric conversion layer formed on a conductive substrate by a semiconductor manufacturing process; Electronic components of the power conversion circuit are mounted on one surface of a circuit board having a conductive layer and an insulating layer, and the conductive substrate and the other surface of the circuit board are fixed with a conductive material. A method for manufacturing a solar cell module. 12. The method according to claim 10, wherein the electronic component is mounted on a side opposite to the photoelectric conversion layer. 13. The method for manufacturing a solar cell module according to claim 10, wherein the electronic component is mounted on the same side as the photoelectric conversion layer. 14. The method for manufacturing a solar cell module according to claim 10, wherein the electronic component is a surface mount component. 15. The method according to claim 14, wherein the surface mount component includes a bare chip type semiconductor component. 16. The method for manufacturing a solar cell module according to claim 10, wherein a plurality of the photoelectric conversion layers are stacked. 17. The power conversion circuit according to claim 10, wherein the power conversion circuit is provided for each element of the thin-film solar cell.
17. The method for manufacturing a solar cell module according to any one of the above items.