Advanced alkaline texturing and cleaning for PERC and SHJ solar cells

Abstract

The seventh edition of the ITRPV specifies a throughput for new wet benches of 7200 wph, with an increase up to 10000 wph until 2026. In this work, an advanced process sequence for high throughput alkaline texturing is described that allows tool manufacturers to reach the ITRPV scenario. This sequence furthermore enables increased batch sizes and integration into existing production lines. Using a new wetting agent, the texturing time was reduced from 12 to 6 minutes. Moreover the texturing bath’s lifetime was extended up to 1000 runs, while simulated chemical and waste concentrations within the process baths even suggest the possibility of a continuous process. Further improvements could be achieved with respect to water and chemical consumption, as well as the avoidance of organically loaded waste. The described process sequence is built from a modular system and can be easily adapted to different cell concepts. The main steps are described and can be optimized regarding quality and operational costs. For a state-of-the-art PERC system, the uniformity of the alkaline texturing process during a 35-day period on a full production line is reported. To increase the viability of SHJ cells for mass production, the decrease of complexity and costs per wafer is a key step for tool manufacturers. Hence, we present first results from a shortened lab scale production process.