Solar cell

Abstract

The invention discloses a solar cell comprising an N-type monocrystalline silicon chip; an intrinsic amorphous silicon passivation layer which is arranged on the light receiving surface and the light shading surface of the N-type monocrystalline silicon chip; a P-type doped amorphous silicon layer which is arranged on the intrinsic amorphous silicon passivation layer of the light receiving surface of the N-type monocrystalline silicon chip; an N-type doped amorphous silicon layer which is arranged on the intrinsic amorphous silicon passivation layer of the light shading surface of the N-type monocrystalline silicon chip; a transparent conductive film layer which is arranged on the P-type doped amorphous silicon layer and the N-type doped amorphous silicon layer; a copper grid line electrode which is arranged on the transparent conductive film layer of the P-type doped amorphous silicon layer; and a copper grid line electrode which is arranged on the transparent conductive film layer of the N-type doped amorphous silicon layer, wherein the surface of the copper grid line electrodes is completely covered by a tin layer. The disadvantages of silver paste silk screen printing can be overcome, and the solar cell also has the advantages of enhancing the conversion efficiency and reducing the technology cost; and then tin is covered on the surface of the copper grid line electrodes so that oxidation of the copper grid line electrodes after long time of placing in the air can be prevented, and the tin can also be used as a weld-aid layer to connect a main grid and a welding strip to increase the adhesive force between the main grid and the welding strip.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a solar cell. Background technique [0002] With the rapid development of the photovoltaic industry, the market urgently needs a solar cell industrialization preparation technology with simple process flow and high photoelectric conversion efficiency to reduce the cost of photovoltaic power generation, so that the cost of photovoltaic power generation can be equal to or lower than the price of mains electricity. The goal. [0003] The crystalline silicon heterojunction solar cell is formed by growing a thin layer of amorphous silicon on a crystalline silicon substrate to form a PN junction, that is, a heterojunction cell of the emitter. It has a simple structure, low process temperature, high conversion efficiency, and good temperature characteristics. It is one of the high-efficiency solar cells suitable for large-scale popularization and application, and has a good develop...

AI Technical Summary

Problems solved by technology

For traditional crystalline silicon solar cells, the screen printing technology uses high-temperature silver paste, which is sintered at a high temperature (about 850°C) to form an alloy layer between the silver grid lines and the silicon surface, which ensures the adhesion between the silver lines and the surface of the cell. , but the process temperature of heterojunction solar cells does not exceed 250°C, so only low-temperature silver paste can be used to meet the process requirements, but after the grid lines printed with low-temperature silver paste are cured at ~200°C, they are not covered with non- The transparent conductive film on the crystalline silicon film layer undergoes a physical or chemical reaction, resulting in poor bonding between the two, which will lead to problems in subsequent cell string welding and component packaging

In addition, the silver grid wire electrode formed by screen printing technology generally has poor conductivity, and it is difficult to achieve a line width of <80 μm to increase the effective light absorption area, which brings difficulties to improve the photoelectric conversion efficiency of the cell.

In addition, one of the characteristics of heterojunction solar cells is that the back uses dense grid lines, and its grid line density is 2-3 times that of the light-receiving surface. Therefore, excessive silver usage will significantly increase the manufacturing cost of the solar cells.

Using screen printing technology, it is necessary to print the top and back of the cell separately. After the top is printed, it needs to be baked at a low temperature. After the grid line is cured, it is turned over and printed on the back, which increases the complexity of the process. And the copper grid wire electrode is polluted and oxidized image battery performance

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