Design guidelines for a metallization scheme with multiple-emitter contact lines in BC-BJ solar cells

This work presents a study on back contact-back junction solar cells when using a metallization scheme with multiple-emitter contact lines. For this purpose, TCAD-based simulations have been carried out by taking into account realistic parameters and state-of-the-art physical models for silicon solar cells. The analysis has been performed by varying different geometrical parameters related to rear metallization, such as the number of the emitter contacts and the emitter metal coverage. In general, an efficiency improvement has been observed by uniformly placing the multiple contacts along the emitter region and by increasing the number of the emitter metal lines. An optimal emitter metallization fraction has been found for different numbers of contacts as a result of the tradeoff between recombination losses at metal/silicon interfaces and series resistance losses. Moreover, the effect of the multiple-emitter contacts has been evaluated as a function of the finger length, the emitter width, and the rear pitch.