Shinzo Sugai

Bus Electrode Having Same Thermal Expansion Coefficient as Crystalline Silicon Solar Cell

It is well known that bus electrode plays a main role in series resistance of solar cells. Bus electrodes composed of the bare leads, of which thermal expansion coefficients are less than cells, coated with highly conducting metals were investigated. These leads exhibited the lower expansion coefficient than expected by the empirical law, and the origins of these phenomena were explained. Work hardening effect on expansion coefficient was then measured. Solar cell fabrication with these leads and rigid solders rationalized assembly processing. Cell characteristics proved to be excellent compared with conventional ones. Finally, lead costs were compared for various materials.