Conductive adhesives for low-stress interconnection of thin back-contact solar cells

Thin crystalline silicon solar cells cannot be interconnected with standard soldering techniques because of warping and breakage. Interconnection with conductive adhesives showed excellent behavior warping can be avoided and 80μm thin cells do not break during and after interconnection. Contact resistances measured on glued interconnections are similar to soldered contacts. Damp/heat tests show no degradation after 2500 hours at 85°C/85% humidity. Temperature cycling -40/+80°C has shown no effects after 200 cycles. I-V measurements of interconnected thin back-contact cells in mini modules show no loss in fill factor. Test mini modules made with soldered back contacts and glued front contacts show excellent performance even after over 900 cycles. Interconnection with conductive adhesives is a promising technique combining excellent mechanical properties, good conductivity, durability, and low process temperatures thus reducing stress.