A SE-based process for alkali-polished high-efficiency PERC batteries

Abstract

The invention discloses an efficient PERC battery process with alkali polishing based on SE. The process comprises the steps of: alkali polishing: employing an optimized alkali polishing formula to perform alkali polishing of a silicon wafer; and supplementation of an additive replenishing liquid and an alkali replenishing liquid used in alkali polishing in a stepped manner, wherein in the batches1-15, the additive replenishing liquid is 200-350ml, the alkali replenishing liquid is 300-1000ml, and the pure water replenishing liquid is 7-9L, in the batches 16-30, the additive replenishing liquid is 250-400ml, the alkali replenishing liquid is 850-1150ml, and the pure water replenishing liquid is 8-10L, and in the batches 31-60, the additive replenishing liquid is 300-500ml, the alkali replenishing liquid is 1000-1300ml, and the pure water replenishing liquid is 9-11L. The optimal alkali polishing formula is employed and the replenishing modes of the additive replenishing liquid and thealkali replenishing liquid employ the stepped replenishing mode to effectively prolong the service life of the liquid medicine in an alkali polishing tank and improve the productivity, and the consumption of the additive and the alkali is greatly reduced to break through the capacity bottleneck of alkali polishing SE.

Description

technical field [0001] The invention relates to the technical field of photovoltaic solar cells, in particular to an alkali polishing high-efficiency PERC cell process based on SE. Background technique [0002] PERC cell technology has significant performance and cost advantages, driving the application of p-type solar-grade monocrystalline silicon wafers. At the same time, high efficiency, low cost and environmental protection are the mainstream directions for the development of crystalline silicon solar cells. PERC cells mainly form a passivation film on the back side, which requires the back surface to have good flatness. The main research of alkali polishing equipment focuses on polishing the back side, which not only solves the flatness problem of the backside coating, but also can Remove the back N-type diffusion layer, promote the formation of the P+ layer, improve the minority carrier lifetime, and increase the reflectivity of the back surface. Therefore, the intro...

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Problems solved by technology

[0004] For the alkali throwing technology and SE technology, it can be concluded that there are still obvious defects in PERC battery technology in the existing technology: the existing formula and usage method of alkali throwing additive and alkali replenishment liquid, the original formula is to use 1-30 batches Both add the same amount of additives and alkali rehydration, add 300ml of additives in each batch, add 1050ml of alkali rehydration, and 9L of pure water rehydration. The life span makes it impossible to increase the production capacity, and the consumption of additives and alkali cannot save production capacity, so it is impossible to break through the production capacity bottleneck of alkali polishing SE

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