Silver-aluminum paste used for positive electrode of high-performance N type solar cell

Abstract

The invention provides silver-aluminum paste used for a positive electrode of a high-performance N type solar cell. The silver-aluminum paste aims at solving the problems that when homojunction metal aluminum powder serves as additives in silk-screen printing silver-aluminum paste of n type crystalline silicon solar cells, due to the fact that aluminum powder is prone to oxidation, aluminum is prevented from conducting further diffusion and alloying on p+ transmitter layers. The silver-aluminum paste is composed of electric conduction silver powder, glass powder, organic carrier phases and additive aluminum and silicon doped alloy powder, and is characterized in that the aluminum-silicone alloy powder serves as additives and the content of silicone in the aluminum-silicon alloy powder ranges from 1 wt% to 20 wt%. The aluminum-silicone alloy powder is heavily doped in p+ transmitters through diffusion, and therefore highly electrically-conductive loops are formed by silver-silicon transmitters, and the contact resistance is reduced. Due to the silicone in the aluminum-silicone alloy, it is avoided that the silicone in the p+ transmitters is diffused to the electrode due to mutual aluminum and silicone diffusion in the position of interfaces of the silver-silicone transmitters at a high temperature, surface defects of the transmitters can be avoided, electric leakage is reduced, and the open pressure is improved.

Description

technical field [0001] The invention belongs to the field of solar cells, in particular to a silver-aluminum paste material for front electrodes. Background technique [0002] Improving conversion efficiency and reducing costs are the goals that solar photovoltaics have been pursuing. Because common metal impurities such as iron have a larger capture cross section for electrons than for holes, n-type silicon has a higher minority carrier lifetime than p-type silicon under low injection conditions. Among solar-grade silicon materials, the effective minority carrier lifetime of n-type Cz silicon is above 1 ms, and even the minority carrier lifetime of n-type polysilicon can reach 100 μs, which is much higher than that of p-type crystalline silicon. Therefore, compared with p-type silicon, n-type crystalline silicon is more qualified to improve the conversion efficiency of solar cells, especially high-efficiency solar cells, such as IBC, HIT, double-sided cells, etc., have hig...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem that the elemental metal aluminum powder is used as an additive in the screen printing silver-aluminum paste of n-type crystalline silicon solar cells, and the aluminum powder is easily oxidized to prevent further diffusion and alloying of aluminum to the p+ emitter layer, the present invention provides a front side of an N-type solar cell Silver-aluminum paste is used for electrodes, and pure metal aluminum powder is replaced by aluminum-silicon alloy powder, which is used for p+ contact of n-type crystalline silicon solar cells

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