Towards a manufacturable back-contact emitter-wrap-through silicon solar cell

Abstract

The emitter-wrap-through ( E W ) silicon solar cell is an all back-contact cell design that features a high efficiency while using solar-grade silicon materials. This paper reports on progress towards a low-cost manufacturable back-contact cell using the EWT design.We first show that the E W cell is particularly well suited for thin (-=ZOO pm) silicon solar cells. In particular, the EWT cell structure is inherently able to obtain high efficiencies (17% range) from lowquality materials by using thinner substrates and due to the double-sided canier colfection afforded by the n+pn* structure, Secondly, we show that the manufacturing process is largely similar to conventional solar cells. Detailed estimates of manufacturing costs find that the EWT module could potentially reduce costs by one-half compared to current technology using front-contacted cells with screen-printed metallizations. Finally, we report on progress on several key processing steps required for a low-cost EWT cell design and process.

The laboratory technology of crystalline silicon solar cells

“…• For improve the back side wafer contact these were high doping with boron by prediffusion from solid source B + at T=1050°C/N 2 [2]. The prediffused layer characteristics: the deep x j =0.6µm and V/I=4-5Ω.…”

Light-Induced Plating of Screen-Printed Multi-Crystalline Silicon Solar Cells

“…3,4 In addition, numerous approaches in cell designs, e.g. back contacts, emitter-wrap-through, metal-wrap-through, PERL/ PERT cells, and bifacial cells, just to mention a few, have been demonstrated successfully with high cell efficiency, [5][6][7][8][9][10][11][12] but are not broadly used in commercial-scale manufacturing due to high cost.…”