JP2007081439A - Manufacturing method of solar battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a solar battery by which the problem of an electrical short-circuit during an assembly step can be radically solved and which has high quality and advantageous yield. <P>SOLUTION: This manufacturing method comprises: a step for adhering a plurality of first conductive-type spherical substrates 11 to a conductive module substrate 13; a step for coating the spherical substrates 11 with an insulating resin 14; and a step for disposing a second conductive-type silicon thin film 17 on the surfaces of the spherical substrates 11 and the surface of the insulating resin 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a solar cell, and more particularly to a method for manufacturing a solar cell using a spherical substrate.

  An internal electric field is generated at the pn junction portion of the semiconductor. When light is applied to the semiconductor to generate an electron-hole pair, the generated electron and hole are separated by the internal electric field, and the electron is positively connected to the n side. The holes are collected on the p side, and when a load is connected to the outside, a current flows from the p side to the n side. Utilizing this effect, solar cells are being put to practical use as elements that convert light energy into electrical energy.

  In recent years, a technique for manufacturing a semiconductor element by forming a circuit pattern on a spherical semiconductor (Ball Semiconductor) having a diameter of 1 mm or less such as single crystal or polycrystalline silicon has been developed.

As one of them, a method for manufacturing a solar array in which a large number of semiconductor particles are connected using aluminum foil has been proposed (Japanese Patent Laid-Open No. 6-13633). In this method, as shown in FIG. 4, the semiconductor particles 207 having the first conductivity type skin portion and the second conductivity type inside are arranged so as to protrude from both sides of the aluminum foil 201 into the opening of the aluminum foil, and the skin on one side is arranged. The portion 209 is removed and an insulating layer 221 is formed. Next, a part of the second conductivity type inside 211 and the insulating layer 221 thereon are removed, and the second aluminum foil 219 is bonded to the removed region 217. The flat region 217 provides good ohmic contact with the second aluminum foil 219 serving as a conductive portion.
JP-A-6-13633

  However, in the solar cell in which the semiconductor particles having the first conductivity type skin portion and the second conductivity type inside as described above, that is, the cells of spherical diodes having a pn junction are spread, the module substrate (described above) in the assembly process When mounting the cell on the second aluminum foil 219) of the conventional example, the exposed part of the p-type silicon layer and the n-type silicon layer part constituting the spherical diode are both in contact with the module substrate serving as an electrode, There was a problem that it was easy to be electrically short-circuited.

  The present invention has been made in view of the above problems, and can provide a method for manufacturing a high-quality and high-yield solar cell that can drastically eliminate the problem of electrical short-circuit in an assembly process. With the goal.

The first aspect of the present invention includes a step of bonding a plurality of first conductivity type spherical substrates to a conductive module substrate, a step of covering the spherical substrate with an insulating resin, a surface of the spherical substrate, and an insulating resin. Depositing a second conductivity type silicon thin film on the surface.
According to such a configuration, the exposed portion of the first conductive type spherical substrate constituting the spherical diode and the second conductive type silicon surface layer portion both come into contact with the module substrate serving as an electrode, so-called electrical. Can prevent a short circuit. Furthermore, the process of depositing a transparent electrode member can be omitted.

The second aspect of the present invention is characterized in that when the spherical substrate of the first conductivity type is bonded to the module substrate, the spherical substrate is bonded using a corresponding conductive paste individually.
According to such a configuration, since the conductive paste is applied to the spherical substrate or the module substrate, the electrical connection between the spherical substrate and the module substrate can be ensured.

A third aspect of the present invention is characterized in that after adhesion by the conductive paste, at least a position where the conductive paste is covered is covered with an insulating resin.
According to this configuration, it is possible to more reliably prevent a short circuit between the exposed portion of the first conductive type spherical substrate and the second conductive type silicon surface layer portion.

According to a fourth aspect of the present invention, a sheet-like one is used as the module substrate.
According to such a configuration, a manufacturing method (Real to Real format) in which each processing step is continuously performed in a flow operation while the roll-shaped module substrate is continuously pulled out, and is finally wound into a roll shape. Can be adopted.

As described in detail above, according to the method for manufacturing a solar cell according to the present invention, the problem of electrical short-circuit in the assembly step of the solar cell can be drastically solved, and the manufacturing method has high quality and good yield. Can be provided.
Further, according to the manufacturing method of the present invention, since it can be manufactured using a sheet-like module substrate, each processing step is continuously performed by a flow operation while continuously drawing out the roll-shaped module substrate. Finally, it is possible to employ a manufacturing method (Real to Real format) that winds up in a roll shape, and the productivity can be drastically improved.

Hereinafter, embodiments of a method for manufacturing a solar cell according to the present invention will be described in detail with reference to the drawings.
In the following embodiments, a description will be given assuming that the first conductivity type is p-type and the second conductivity type is n-type. However, the first conductivity type can be similarly manufactured if the n-type and the second conductivity type are p-type.

  The solar cell manufactured by the method for manufacturing a solar cell according to the present embodiment has solar cells 10 spread on a sheet-like module substrate 13 as shown in FIG. As shown in the schematic cross-sectional view, a plurality of first conductive type spherical substrates 11 are adhered to the surface of the spherical substrate 11 on the surface of the spherical substrate 11 in a state where the first conductive type spherical substrates 11 are bonded to each other by the conductive paste 12. The silicon thin film 17 is deposited, and the silicon thin film 17 and the module substrate 13 are electrically insulated by the insulating resin 14.

Next, an example of a specific manufacturing method will be described below.
FIG. 3 is a manufacturing process diagram illustrating an intermediate step of the method for manufacturing a solar cell according to the present invention.
As shown in FIG. 3 (a), a conductive paste (on a part) of a spherical substrate 11 made of p-type polycrystalline silicon grains or p-type amorphous silicon grains having a diameter of about 0.25 mm to 10 mm is used. For example, a silver paste) 12 is applied and mounted on a module substrate (for example, an aluminum sheet) 13. At this time, the conductive paste 12 may be applied to the module substrate 13 in advance.

  Next, as shown in FIG. 3B, for example, the transparent transparent flexible resin powder 14a which is an insulating resin having a melting point of 660 ° C. or less which is the melting point of aluminum is applied to the spherical substrate 11. Sprinkle from the top.

  Then, by reflowing at a temperature of 660 ° C. or less which is the melting point of aluminum, the surface of the module substrate 13 and the lower part of the spherical substrate 11 including the portion of the conductive paste 12 are filled with the above-mentioned thermoplastic transparent flexible resin powder 14a. By melting, it is covered with the insulating resin 14. At this time, at least the position where the conductive paste 12 is covered is covered with the insulating resin 14. As a result, the state shown in FIG.

  After the process up to the step (c) in FIG. 3, the oxide film on the surface of the p-type spherical substrate 11 is removed by etching, and the n-type silicon thin film 17 is removed from the surface of the p-type spherical substrate 11 by, for example, the CVD method. And it deposits so that the insulating resin 14 may be covered. Thereby, a solar cell as shown in FIG. 2 is obtained.

  In the present embodiment, a transparent electrode member (not shown) is not necessarily deposited on the outer surface of the silicon thin film 17.

It is a general view of the solar cell manufactured by the manufacturing method of the solar cell which concerns on embodiment of this invention. It is a cross-sectional schematic diagram which shows the solar cell manufactured by the manufacturing method of the solar cell which concerns on embodiment of this invention. It is a manufacturing process figure explaining the manufacturing method of the solar cell which concerns on embodiment of this invention. It is a figure which shows the solar cell of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Solar cell 11 Spherical substrate 12 Conductive paste 13 Module substrate 14a Thermoplastic transparent flexible resin powder 14 Insulating resin 17 Second conductive type silicon thin film

Claims (4)

Bonding a plurality of first conductivity type spherical substrates to a conductive module substrate;
Covering the spherical substrate with an insulating resin;
Depositing a second conductive type silicon thin film on the surface of the spherical substrate and the surface of the insulating resin. 2. The method of manufacturing a solar cell according to claim 1, wherein when the first conductive type spherical substrate is bonded to the module substrate, the spherical substrate is bonded using a corresponding conductive paste individually. A method for manufacturing a solar cell. 3. The method for manufacturing a solar cell according to claim 2, wherein after the bonding with the conductive paste, at least a position covering the conductive paste is covered with an insulating resin. Method. 4. The method for manufacturing a solar cell according to claim 1, wherein the module substrate is a sheet.

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