JPH0917823A - Solar cell and method of manufacturing this solar cell - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide and manufacture a solar cell in which a lead wire is firmly fixed to a power generating element and a plastic layer can sufficiently protect the power generating element in a simple process. [Construction] In the solar cell, the surface of a power generation element 1 is covered with a transparent plastic layer 2. The lead wire 4 is soldered and connected to the terminal portion of the power generation element 1. The solder 3 for connecting the lead wire 4 to the terminal portion penetrates the plastic layer 2 and is sandwiched between the inner surface of the plastic layer 2 and the surface of the terminal portion, and has an area larger than that of the through portion 5 on the inner surface. To be the anchor portion 3A.
The anchor portion 3A is sandwiched between the plastic layer 2 and the terminal portion, and the lead wire is firmly connected to the terminal portion. In the method of manufacturing the solar cell, the solder 3 is attached to the surface of the terminal portion of the power generation element 1, and the plastic layer 2 is adhered to the surface. When connecting the lead wire 4, a part of the plastic layer 2 covering the surface of the terminal portion is melted and removed, and the lead wire 4 is connected to the solder 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell in which a lead wire is connected to a power generating element by a unique method and a method for manufacturing the solar cell. In particular, the present invention relates to a solar cell having an optimal structure for connecting a lead wire to a film-shaped solar cell, and a method for manufacturing this solar cell.

[0002]

2. Description of the Related Art Some solar cells are provided with a plastic layer for protecting the surface. In this solar cell, it is necessary to connect a lead wire to the power generation element inside the plastic layer. This is because electric power is taken out from the power generation element inside the plastic layer. FIG. 8 shows a structure of a terminal portion of a conventional solar cell in which a plastic layer is provided on the surface and a lead wire is connected to the power generating element on the inner surface of the plastic layer. In the solar cell shown in this figure, in order to connect the lead wire 4 to the terminal portion of the power generation element 1, a part of the plastic layer 2 covering the surface of the power generation element 1 is opened. The opening 15 of the plastic layer 2 is located in a portion that connects the lead wire 4 to the terminal portion of the power generation element 1. The solar cell having this structure is manufactured by closely adhering a plastic film having an opening to the surface of the power generation element 1. When the plastic film is attached to the power generation element 1, the opening 15
Must be accurately aligned with the connecting portion of the lead wire 4.
This is because the opening 15 is displaced from the connecting portion of the lead wire 4 when the position where the plastic film is closely attached is displaced.

[0003]

The solar cell of this structure has a drawback that it is difficult to accurately align the plastic film and bring it into close contact with the surface of the power generating element. Also,
If the plastic film is misaligned, the lead wires cannot be connected, and this also has a drawback that the yield of products is reduced.

Further, the solar cell having this structure has a drawback that it is difficult to firmly connect the lead wires. When the opening area of the plastic film is increased in order to firmly connect the lead wire 4 to the terminal portion over a wide area, the action of the plastic film for protecting the power generation element 1 is reduced. When the surface protection effect of the plastic film is lowered, the adhesive portion between the power generation element 1 and the polyimide resin 10 is peeled off when the lead wire 4 is strongly pulled. This is because it is difficult to increase the adhesive strength of this portion. The plastic film that covers the surface of the power generation element 1 also has a function of being in close contact with the surface of the power generation element 1 and sandwiching the power generation element 1 with the polyimide resin 10. In order for the plastic film to sufficiently protect the power generating element 1, it is important to make the opening area for connecting the lead wire 4 as small as possible.
However, if the opening area of the plastic film is made small, it is necessary to adhere the plastic film to the power generating element 1 with extremely high accuracy, and the lead wire 4 cannot be firmly adhered to the terminal portion in a large area. Therefore, the plastic film cannot sufficiently protect the power generating element 1 when the opening area is increased, and when the opening area is decreased, the lead wire 4 is not formed.
Will reduce the connection strength. The protection of the power generation element 1 by the plastic film and the strengthening of the connection strength of the lead wire 4 are contradictory properties, and it is difficult to satisfy both of them.

Further, instead of the plastic film, a transparent plastic can be applied to the surface of the power generating element to manufacture a solar cell. FIG. 9 shows a cross-sectional view of a solar cell having this structure. In the solar cell shown in this figure, the transparent plastic 16 can be applied to form the plastic layer 2 on the surface of the power generating element 1. Therefore, the uncured transparent plastic 16 in the paste form can be applied by the printing method. it can. Therefore, the plastic layer 2 can be adhered to an accurate position. However, the solar cell with this structure also
In order to bond the lead wire 4, it is necessary to open a part of the plastic layer 2. Therefore, also in the solar cell having this structure, if the opening area is reduced so that the plastic layer 2 can sufficiently protect the power generating element 1, the lead wire 4 cannot be firmly connected. On the contrary, if the opening area of the plastic layer 2 is increased so that the lead wire 4 is firmly connected to the terminal portion over a wide area, the action of the plastic layer 2 for protecting the power generating element 1 is reduced, and the result shown in FIG. The same harmful effect as the solar cell shown occurs.

The present invention was developed for the purpose of preventing such an adverse effect, and an important object of the present invention is to connect a lead wire firmly to a terminal portion of a power generating element and to generate electricity by a plastic layer. It is an object of the present invention to provide a solar cell capable of sufficiently protecting an element, capable of mass-producing efficiently and inexpensively, and a method of manufacturing the same.

[0007]

[Means for Solving the Problems] The solar cell of the present invention has the following features in order to achieve the above-mentioned object. In the solar cell described in claim 1, the surface of the power generation element 1 is covered with a transparent plastic layer 2. The lead wire 4 is attached to the terminal portion of the power generation element 1 covered with the plastic layer 2.
Are soldered and connected. Furthermore, in the solar cell of the present invention, the solder 3 that connects the lead wire 4 to the terminal portion is
While penetrating the plastic layer 2, the plastic layer 2
It is sandwiched between the inner surface of and the surface of the terminal portion. The solder 3 penetrating the plastic layer 2 is enlarged to have an area larger than that of the penetrating portion 5 on the inner surface of the plastic layer 2 to form an anchor portion 3A. The anchor portion 3A of the solder 3 is sandwiched between the plastic layer 2 and the terminal portion, and is firmly connected to the terminal portion via the anchor portion 3A.

Further, in the method of manufacturing a solar cell according to claim 2 of the present invention, the surface of the plastic layer 2 is transparent.
This is an improved method of manufacturing by soldering the lead wire 4 to the terminal portion of the power generating element 1 covered with. In this manufacturing method, the solder 3 is attached to the surface of the terminal portion of the power generating element 1, and then the plastic layer 2 is adhered to the surface of the terminal portion covered with the solder 3 and the surface of the power generating element 1. When connecting the lead wire 4 to the terminal portion, it is necessary to melt and remove a part of the plastic layer 2 covering the surface of the terminal portion, and connect the lead wire 4 to the solder 3 from which the plastic layer 2 has been removed. Characterize.

[0009]

In the solar cell having the sectional structure of FIG. 3 showing the preferred embodiment of the present invention, the lead wires are connected in the following steps. The solder 3 is attached to the surface of the terminal portion of the power generating element 1. In the solar cell shown in the figure, Cu paste 7 is applied onto Ag paste 6 to form a terminal portion. A plastic film is brought into close contact with the entire surface of the power generation element 1 including the terminal portion, and the entire surface of the power generation element 1 is covered with the plastic layer 2 composed of the plastic film. The surface of the terminal portion is heated to connect the lead wire 4 to the solder 3 on the surface of the terminal portion. The plastic layer 2 covering the surface of the terminal portion is melted and removed by a soldering iron for soldering the lead wires 4. When the plastic layer 2 is removed, the solder 3 attached to the surface of the terminal portion is melted and the lead wire 4 is connected thereto.

Particularly, in the solar cell of the present invention and the manufacturing method thereof, the plastic layer 2 is formed after the solder 3 is attached to the terminal portion.
It is covered with. The terminal portion to which the solder 3 is attached on the surface can surely connect the lead wire 4 when the plastic layer 2 is melted and removed. Heat the plastic layer 2,
This is because the solder 3 attached to the surface of the terminal portion is melted when it is melted and removed, and the lead wire 4 is connected thereto. The melting plastic layer 2 does not enter between the terminal portion and the solder 3 to reduce the connection strength of the lead wire 4. This is because the solder 3 is attached to the surface of the terminal portion before the plastic layer 2 is adhered. Therefore, even if the plastic layer 2 is melted and removed, it does not reduce the strength for connecting the lead wire 4 to the terminal portion.

Further, in the solar cell having the structure shown in FIG. 3 in which the lead wire is connected to the terminal portion, the solder 3 penetrating the plastic layer 2 is expanded to an area larger than the penetrating portion 5 on the inner surface of the plastic layer 2. It is the anchor portion 3A. The anchor portion 3A is sandwiched between the plastic layer 2 and the terminal portion. In this structure, the lead wire 4 can be connected to the terminal portion in a wide area, and the lead wire 4 can be firmly connected to the terminal portion by the anchor portion 3A covered with the plastic layer 2.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. However, the examples described below exemplify a solar cell and its manufacturing method for embodying the technical idea of the present invention, and the present invention does not specify the solar cell and its manufacturing method as follows. .

Further, in this specification, in order to make it easy to understand the claims, the numbers corresponding to the members shown in the embodiments will be referred to as "claims", "actions", and "actions". In the column of "Means for solving the problem". However, the members shown in the claims are
It is by no means specific to the members of the embodiment.

The solar cell shown in FIGS. 1 to 3 has an amorphous silicon layer (a-Si layer) 1 on the metal layer 8.
A is laminated, and ITO 9 having electroconductivity and translucency is laminated on the a-Si layer 1A to form the power generating element 1. ITO
On the surface of 9, the Ag paste 6 is formed in a comb shape as shown in FIG.
Is applied. On the Ag paste, the Cu paste 7 is applied to the portion where the lead wire 4 is connected, and the Cu paste 7
The part coated with is the terminal part. Further, the plastic layer 2 is adhered to the entire surface of the power generation element 1 including the terminal portion in a close contact state, and the back surface of the metal layer 8 is adhered and covered with the polyimide resin 10 which is a plastic film having excellent heat stress resistance. There is. The solar cell of this structure has both surfaces covered with a plastic film.

The plastic layer 2 is preferably a thermoplastic plastic film, for example, a film of polyimide resin, polyethylene resin, polyvinyl chloride resin, polypropylene resin, nylon resin, EVA, or the like, which is a single layer or is laminated. Film used.
The plastic film is adhered in close contact. The plastic film is preferably a thermoplastic plastic film, but any film that can be removed by heating can be used. Further, instead of the plastic film, the plastic layer 2 may be one in which uncured plastic is applied and cured. The plastic layer 2 thus provided can also be made of plastic that can be removed by heating, such as urethane resin or acrylic resin.

The solar cell shown in FIG. 1 and FIG.
Is composed of three power generation modules 1a, and the power generation modules 1a are connected in series to increase the output voltage. a-S
The ITO 9 adhered to the upper surface of the i layer 1A in a close contact state has a small electric resistance due to the Ag paste 6 applied to the surface thereof, so that current is efficiently collected. It is possible to solder the lead wire 4 directly to the Ag paste 6, but in order to solder more firmly, C
The u paste 7 is applied to form the terminal portion.

Solder 3 is applied to the surface of the terminal portion composed of Cu paste 7. The solder 3 is attached to the terminal portion in a step prior to the adhesion of the plastic layer 2. The solder 3 attached to the terminal portion not covered with the plastic layer 2 is attached to the terminal portion in an ideal state. This is because the plastic layer 2 does not hinder the adhesion of the solder 3. The solder 3 is melted and brought into close contact with the terminal portion.

As shown in FIG. 3, the solder 3 on the surface of the terminal portion
The lead wire 4 is connected to. The solder 3 penetrates the plastic layer 2 and connects the lead wire 4 to the terminal portion.
Since the solder 3 for connecting the lead wire 4 is attached to the surface of the terminal portion, it is sandwiched between the plastic layer 2 and the terminal portion. In this state, the solder 3 that connects the lead wire 4 to the terminal portion is expanded to have an area larger than the through portion 5 on the inner surface of the plastic layer 2 and becomes the anchor portion 3A. The anchor portion 3A is sandwiched between the plastic layer 2 and the terminal portion, and connects the lead wire 4 to the terminal portion so as not to come off. Further, the plastic layer 2 covering the terminal portion covers the terminal portion with a large area on the inner surface of the plastic layer, and effectively prevents the lead wire 4 from peeling and the power generating element 1 from peeling.

The solar cell having this structure is manufactured by the process shown in FIG.
It is manufactured as follows. The Cu paste 7 is applied to the terminal portion on the surface of the Ag paste 6 provided on the ITO 9. Cu paste 7
Is applied to the portion to which the lead wire 4 is connected. In the solar cell shown in FIG. 1, Cu paste 7 is applied to the lower portions on both sides to provide terminal portions. Solder 3 on the terminal part composed of Cu paste 7
To adhere. The solder 3 is melted and attached to the surface of the terminal portion. The solder 3 is attached to almost the entire surface of the terminal portion. However, solder may be attached to a part of the terminal portion.
If the area where the solder adheres is small, the lead wire cannot be firmly connected. Therefore, the solder is attached to the terminal portion in the largest possible area. A plastic film is adhered to form a plastic layer 2 with the entire surface of the a-Si layer 1A covered with ITO 9 being covered. The terminals are also covered with the plastic layer 2. The lead wire 4 is soldered to the solder 3 attached to the terminal portion. At this time, the heat of soldering the lead wire 4 melts and removes part of the plastic layer 2 covering the surface of the terminal portion. The lead wire 4 is connected to the solder 3 exposed on the surface after the plastic layer 2 is removed.

In the above embodiment, C is formed on the Ag paste 6.
The u paste 7 is applied to provide terminals. The solar cell of the present invention and the method for manufacturing the same do not specify the structure of the terminal portion as described above. For example, as shown in FIG. 6, a metal foil 11 may be attached onto the Cu paste 7 to form a terminal portion. In the solar cell having this structure, the metal foil 11 is bonded to the conductive surface of the power generation element 1 via the adhesive layer 12. In order to electrically connect the metal foil 11 to the conductive surface, a communication hole 13 is opened through the metal foil 11 and the adhesive layer 12. Communication hole 1
3 is filled with a conductive adhesive material 14 such as solder. The conductive adhesive 14 of the communication hole 13 adheres the metal foil 11 to the conductive surface, and further electrically connects the metal foil 11 to the conductive surface.

Adhesive layer 12 for adhering the metal foil 11 to the conductive surface
Is an epoxy resin. Since the epoxy resin has a heat resistant temperature of up to 300 ° C., it has a feature that when the metal foil 11 is soldered, peeling of the metal foil 11 can be effectively prevented. However, for the adhesive layer 12, a polyurethane resin, an unsaturated polyester resin, a polyester dimethacrylate, an acrylic copolymer, a cyanoacrylate, a rubber-based adhesive, a pressure-sensitive adhesive or the like can be used instead of the epoxy resin.

FIG. 5 is a plan view of the solar cell shown in FIG. In the solar cell shown in this figure, the metal foil 11 of the terminal portion is
As a rectangular shape, communication holes 13 are opened at both ends, and the lead wire 4 is connected to the central portion. The communication hole 13 penetrates the metal foil 11. An adhesive is applied to the back surface of the metal foil 11 provided with the communication holes 13. The adhesive is not applied to the portion of the communication hole 13. The metal foil 11 is adhered to the conductive surface via the applied adhesive. Since no adhesive is applied to the portion of the communication hole 13, the communication hole 13 is provided so as to penetrate both the metal foil 11 and the adhesive layer 12.

A conductive adhesive material 14 such as solder is provided in the communication hole 13.
Is filled. The conductive adhesive 14 of the communication hole 13 securely fixes the metal foil 11 on the conductive surface, and
Is electrically connected to the conductive surface. Solder is most suitable for the conductive adhesive 14 that connects the metal foil 11 to the conductive surface. However, the conductive adhesive 14 is not limited to solder, but the communication hole 13 can be filled to connect the metal foil 11 to the conductive surface, and the metal foil 11 can be connected.
Anything that can make an electrical connection to a conductive surface, such as Cu
A conductive paste such as paste or Ag paste can also be used.

In a solar cell using solder as the conductive adhesive 14 for connecting the metal foil 11 to the conductive surface, the communication hole 13 is filled with solder, and the solder 3 is attached to almost the entire surface of the metal foil 11 which is the terminal portion. Let In a solar cell using a conductive paste for the conductive adhesive 14 that connects the metal foil 11 to the conductive surface, after filling the communication holes 13 with the conductive paste, the metal foil 1
Solder 3 is attached to the surface of 1. Solder on metal foil surface 3
Connects the lead wire 4 to the metal foil 11.

The lead wire 4 is connected to the surface of the metal foil, that is, the surface of the terminal portion. The lead wire 4 is soldered to the terminal portion by melting and removing the plastic layer 2. Before soldering the lead wires 4, the entire surface of the power generation element 1 covered with ITO 9 is covered with the plastic layer 2. The plastic layer 2 is in close contact with the surface of the power generation element 1 including the terminal portion and covered with the ITO 9. In the plastic layer 2,
What was used for the solar cell shown in FIGS. 1 to 3 can be used.

FIG. 7 shows a step of connecting lead wires to the solar cells shown in FIGS. 5 and 6. In the process shown in this figure, the lead wire is connected to the power generating element as follows. The Cu paste 7 is applied to the surface of the Ag paste 6 provided on the ITO 9. The Cu paste 7 is applied to the portion where the metal foil 11 is fixed. The metal foil 11 is connected to the Cu paste 7 via the adhesive layer 12 to form a terminal portion. Metal foil 11 and adhesive layer 12
Has a communication hole 13. The communication hole 13 between the metal foil 11 and the adhesive layer 12 is filled with solder which is the conductive adhesive material 14, and the solder 3 is attached to the upper surface of the metal foil 11. The plastic layer 2 is provided in close contact with the power generation element 1 and the entire conductive surface. The lead wire 4 is soldered to the solder 3 connected to the upper surface of the metal foil 11. At this time, the plastic layer 2 is heated and removed.

Although the above-described embodiments have detailed the structure in which the lead wire is connected to the film-shaped solar cell, the present invention does not specify the solar cell as a film-shaped one. This is because it can be used for all solar cells in which a metal foil is connected to the conductive surface of the power generation element and a lead wire is connected to this metal foil.

[0028]

The solar cell of the present invention is simple and easy to use.
Moreover, it has the feature that it can be connected so that the lead wire cannot be disconnected. This is because the solar cell of the present invention connects the lead wire to the terminal portion by the solder serving as the anchor portion. The surface of the terminal portion of the power generation element is coated with solder, and a plastic layer is coated thereon. The lead wire connected to the terminal portion is connected to the solder on the surface of the terminal portion by the solder penetrating the plastic layer on the surface of the power generating element. Since the lead wire and the terminal portion are connected by the solder, the lead wire is firmly connected to the power generating element and is also electrically connected. Further, the solder connecting the lead wire to the terminal portion penetrates the plastic layer and is connected to the surface of the terminal portion as an anchor portion having a large area on the inner surface of the plastic layer. Since the solder of the anchor portion has a larger area than the through hole and is sandwiched between the inner surface of the plastic layer and the surface of the terminal portion, the lead wire is more firmly fixed to the terminal portion. This, together with the connection between the solders, ensures that the lead wire is electrically connected to the power generating element, and does not come off from the connecting portion even if it is pulled a little strongly.

Further, in the solar cell manufacturing method according to the second aspect of the present invention, the solder is applied to the surface of the terminal portion before the surface of the terminal portion of the power generating element is covered with the plastic layer. A plastic layer is adhered on the terminal portion covered with the solder in a state of being in close contact with the terminal portion. When connecting the lead wire to the terminal portion in this state, a part of the plastic layer is melted by heat and the lead wire is soldered to the solder exposed on the surface of the terminal portion. With this method, the plastic layer can be removed when the lead wire is soldered, so that it is not necessary to previously provide a through hole in the plastic layer. For this reason, the work is simplified, and it is not necessary to accurately position and bond the terminals to the terminals using a plastic sheet with through holes as a separate member. it can. Furthermore, since only the plastic layer of the part where the lead wire is soldered is removed, only the connecting part of the lead wire appears on the surface,
Other terminals are not exposed. Therefore, the terminal portion can be protected without being exposed to the outside unnecessarily. Also, the solder becomes an anchor part, which has a large area inside the plastic layer and comes into contact with the terminal part, and the lead wire is securely electrically connected to the terminal part. Since it is sandwiched between the terminal portions, it is possible to prevent the lead wire from being pulled and coming off the terminal portions. Further, since the plastic layer and the polyimide resin sandwich the power generation element, the power generation element can be effectively prevented from peeling off from the polyimide resin.

[Brief description of the drawings]

FIG. 1 is a plan view showing a solar cell according to an embodiment of the present invention.

FIG. 2 is a sectional view of the solar cell shown in FIG. 1 taken along the line AA.

3 is a cross-sectional view of the solar cell shown in FIG. 1 taken along the line BB.

FIG. 4 is a sectional view of each step showing the method for manufacturing a solar cell according to the example of the present invention.

FIG. 5 is a plan view showing a solar cell according to another embodiment of the present invention.

6 is a sectional view of the solar cell shown in FIG. 5 taken along the line BB.

7 is a cross-sectional view showing a step of connecting lead wires to the solar cell shown in FIG.

FIG. 8 is a sectional view showing a structure of a terminal portion of a conventional solar cell.

FIG. 9 is a sectional view showing a structure of a terminal portion of another conventional solar cell.

[Explanation of symbols]

1 ... Power generation element 1A ... a-Si layer 1
a ... Power generation module 2 ... Plastic layer 3 ... Solder 3A ... Anchor part 4 ... Lead wire 5 ... Penetration part 6 ... Ag paste 7 ... Cu paste 8 ... Metal layer 9 ... ITO 10 ... Polyimide resin 11 ... Metal foil 12 ... Adhesive layer 13 ... Communication hole 14 ... Conductive adhesive 15 ... Opening 16 ... Transparent plastic

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Nobuo Hanawa 2-5-5 Keihan Hondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (2)

[Claims] 1. The power generating element (1) has a surface coated with a transparent plastic layer (2), and a lead wire (4) is attached to a terminal portion of the power generating element (1) covered with the plastic layer (2). ) Is connected by soldering, the solder (3) that connects the lead wire (4) to the terminal part penetrates the plastic layer (2) and the inner surface of the plastic layer (2) and the terminal. The solder (3) penetrating the plastic layer (2) is sandwiched between the surface of the part and the inner surface of the plastic layer (2) to a larger area than the penetrating part (5), and the anchor part is formed.
(3A), wherein the anchor part (3A) is sandwiched between the plastic layer (2) and the terminal part. 2. A method for producing a solar cell by soldering a lead wire (4) to a terminal portion of a power generating element (1) whose surface is covered with a translucent plastic layer (2). Attach the solder (3) to the surface of the terminal part of (1), then the surface of the terminal part covered with the solder (3) and the power generation element (1)
When the lead wire (4) is attached to the surface of the terminal and the lead wire (4) is connected to the terminal, the plastic layer (2) covering the surface of the terminal is partially melted and removed.
Lead wire on the solder (3) exposed on the surface after (2) is removed.
A method for manufacturing a solar cell, which comprises connecting (4).