JP2006269890A - Flexible solar cell using sodium chloride for substrate and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive flexible solar cell by making a substrate exfoliate by a simple method, using the substrate material which does not limit the method for film formation of an efficient thin film solar cell. <P>SOLUTION: A manufacturing method of a solar cell is not limited by using NaCl as a substrate material, but an efficient flexible solar cell is easily obtained by dissolving and making an NaCl substrate exfoliate by washing with pure water after the film formation of a solar cell layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a method for manufacturing a solar cell module.

Currently, in the manufacture of solar cells, cost reduction and space saving are emphasized. Solar cells are the main power source for satellites and space stations in particular, but they will be produced, stored, launched, deployed and used in space. At this time, a flexible solar cell capable of increasing the storage capacity and realizing space saving by bending the solar cell is indispensable for future space development. In addition to the use in space, flexible solar cells can be bent thinly, so solar cells can be installed not only on flat surfaces but also on curved surfaces, and power sources for future small electronic devices. Is also expected.

Various methods for manufacturing flexible solar cells have been proposed in the prior art, but the most common method is to grow a solar cell layer on an insulating flexible substrate such as PET or polystyrene. This is a method for producing a flexible solar cell. However, since these flexible substrates are generally vulnerable to high temperatures, many of the high-temperature growth methods cannot be taken out of the crystal growth methods for each layer in the solar cell layer. In addition, flexible substrates such as polyimide with high heat resistance are expensive and difficult to manufacture at a low price. These flexible substrates also have the drawback of poor adhesion.

Moreover, although there exists patent document 1 in a prior art, when removing the board | substrate etc. which are located under a solar cell layer, in order to perform mechanical fracture | rupture, you have to consider so that a fracture surface may become flat after layer fracture. In order to make it flat, it is necessary to select a crystal in which the preferentially coordinated lattice plane is in the same direction as the fracture direction. In addition, since an extra layer that is not included in the configuration of the solar cell is added as an additional layer for breaking, extra cost problems such as lattice matching, materials, and an apparatus for breaking are required.
JP2003-17726

As described above, since conventional substrate materials for flexible solar cells are vulnerable to high temperatures, the method of forming each layer of the solar cell is limited, and it is difficult to manufacture highly efficient flexible solar cells.

Moreover, the substrate material of the conventional flexible solar cell is expensive and is not preferable for mass production.

In order to mechanically break the substrate material, it is necessary to consider the fact that the cross section after the break is flat and the effect of the layer to be broken on solar cell production. The method is not preferred.

The present invention has been made based on such circumstances, and the object thereof is to use a substrate material that does not limit the film formation method of a high-efficiency thin film solar cell, and to inexpensively peel the substrate by a simple method. A flexible solar cell is provided.

In order to solve the above problems, NaCl is used as the substrate material of the flexible solar cell in the present invention. The NaCl substrate is a substrate material often used for semiconductor crystal growth, and is resistant to high temperatures, so the film forming method is not limited. This makes it possible to form a solar cell layer having high conversion efficiency.

Since NaCl easily dissolves in water, it is peeled off by dissolving the NaCl substrate in water taking advantage of this feature after the solar cell layer is formed. A high-efficiency flexible solar cell is manufactured by forming a high-efficiency thin-film solar cell using this method and then peeling off the NaCl substrate.

  According to the present invention, a high-efficiency thin-film solar cell can be produced without any limitation on the film formation method, and can be made flexible by a simple process, which is effective for high efficiency and low cost of the flexible solar cell. In addition, by using this method, it is possible to manufacture a flexible solar cell even with a solar cell material that has been difficult to be flexible. As a result, solar cells are made more flexible with various materials, which contributes to the popularization of solar cells to ordinary households. And the multi-use of solar cells will greatly contribute to the development and development of electronic devices and charge devices.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings of the embodiment, the same or corresponding parts are denoted by the same reference numerals.

First, a first embodiment of the invention will be described below. 1-3 is sectional drawing which shows the manufacturing method of the solar cell by the 1st Embodiment of invention in order of a process.

As a first embodiment, first, for example, an Ag film 2 is 0.8 μm on the NaCl substrate 1 by sputtering, for example, as a back reflective layer and a back electrode, and an n-type Si layer 3 is formed thereon by, for example, plasma CVD (Chemical Vapor Deposition). 0.3 μm is deposited thereon, and 3 μm of amorphous Si 4 and 0.3 μm of p-type Si layer 5 are further deposited thereon as an i layer serving as an active layer. On top of that, for example, an ITO (Indium Tin Oxide) film 6 of 0.5 μm is deposited as a transparent conductive oxide film by a thermal CVD method, for example, an Al / Ni electrode 7 is installed as an electrode to form a solar cell layer portion. At this time, the light confinement effect is enhanced by applying a texture structure by etching the Ag back reflecting layer 2 using, for example, hydrofluoric acid (FIG. 1).

NaCl is easily soluble in water. After the solar cell layer is deposited, NaCl1 in the substrate portion is dissolved, for example, by performing a cleaning process with pure water. (FIG. 2) Thus, a flexible solar cell is obtained by peeling the NaCl substrate 1 from the solar cell layer (FIG. 3).

4-6 is sectional drawing which shows the manufacturing method of the solar cell by the 2nd Embodiment of invention in order of a process.

As a second embodiment, first, for example, a Mo electrode film 8 is 0.8 μm on the NaCl substrate 1 as a back electrode by, for example, sputtering, and a light absorption layer is, for example, p-CIGS (Cu (InGa), for example, by vacuum evaporation. The Se ₂ ) thin film 9 is 2 μm, on which, for example, a buffer layer is deposited by, for example, vapor deposition, for example, a CdS film 10 is 0.1 μm, for example, a semi-insulating film, for example, ZnO film 11 is, for example, 0.3 μm by sputtering. For example, an ITO film 6 of 0.3 μm is deposited as a transparent conductive film by CVD, and an MgF ₂ film 12 of 0.3 μm is deposited as an antireflection film by vacuum deposition, for example, and an Al / Ni electrode 7 is installed as an electrode. Then, a solar cell layer portion is formed (FIG. 4).

After the solar cell layer volume, the substrate portion NaCl1 is dissolved, for example, by washing with pure water (FIG. 5). Thereby, a flexible solar cell is obtained by peeling the NaCl substrate 1 from the solar cell layer (FIG. 6).

7-10 is sectional drawing which shows the manufacturing method of the solar cell by the 3rd Embodiment of invention in order of a process.

When the mechanical strength of the solar cell layer after peeling the NaCl substrate 1 is insufficient as a result of the first and second embodiments of the invention, the electrode parts 2 and 7 are processed before peeling the NaCl substrate 1 (FIG. 4). (FIG. 7).

After processing the electrode parts 2 and 7, for example, a PET flexible substrate 13 is added (FIG. 8).

After adding the flexible substrate 13, the NaCl substrate 1 is peeled off to obtain a flexible solar cell (FIGS. 9 and 10).

Schematic sectional drawing which shows an example of the manufacturing method of the solar cell apparatus of this invention Schematic sectional drawing which shows an example of the manufacturing method of the solar cell apparatus of this invention Schematic sectional drawing which shows an example of the manufacturing method of the solar cell apparatus of this invention Schematic sectional drawing which shows an example of the manufacturing method of the solar cell apparatus of this invention Schematic sectional drawing which shows an example of the manufacturing method of the solar cell apparatus of this invention Schematic sectional drawing which shows an example of the manufacturing method of the solar cell apparatus of this invention Schematic sectional drawing which shows an example of the manufacturing method of the solar cell apparatus of this invention Schematic sectional drawing which shows an example of the manufacturing method of the solar cell apparatus of this invention Schematic sectional drawing which shows an example of the manufacturing method of the solar cell apparatus of this invention Schematic sectional drawing which shows an example of the manufacturing method of the solar cell apparatus of this invention

Explanation of symbols

1 NaCl substrate 2 Ag back reflection layer 3 n-Si layer 4 i-Si active layer 5 p-Si layer 6 ITO transparent conductive film 7 Al / Ni electrode 8 Mo back electrode 9 CIGS light absorption layer 10 CdS buffer layer 11 ZnO half Insulating layer 12 MgF ₂ anti-reflective coating 13 PET flexible substrate

Claims (8)

Solar cell device using NaCl substrate as substrate of solar cell A solar cell device characterized in that a NaCl layer is formed on an insulator substrate and a solar cell layer is formed thereon. A method for producing a solar cell according to claim 1 or 2, wherein a flexible solar cell is obtained by peeling off the NaCl layer from the solar cell layer. The method for producing a solar cell according to claim 3, wherein the NaCl layer is removed by dissolving the NaCl layer. 5. A method for manufacturing a solar cell according to claim 4, wherein the solar cell layer is textured. In the above-described claims 4 and 5, at least one kind of crystal of polycrystalline Si, amorphous Si, III-V, II-VI, or I-III-VI compound semiconductor is used as the light absorption layer of the solar cell. Manufacturing method of solar cell The material constituting the light absorption layer of the solar cell according to claims 4 and 5 includes at least one crystal of polycrystalline Si, amorphous Si, III-V, II-VI, and I-III-VI compound semiconductor. For manufacturing a solar cell A method for producing a solar cell according to any one of claims 1 to 4, wherein a flexible substrate is newly added to the solar cell after peeling off the NaCl layer.

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