A comparison of different module configurations for multi-band-gap solar cells

The use of different module configurations with multijunction (MJ) solar cells was investigated. Module configuration refers to the electrical circuit in which the subcells of the MJ cell are connected. The simplest configuration has the subcells connected in series. The subcells may also be connected in parallel or operated independently. These circuits require MJ cells with more than two terminals. The performance of two-junction tandem cells with different module configurations was analyzed by means of computer modeling. Roughly the same performance was found for an optimized MJ cell with the different module configurations. However, several advantages for MJ cells with the subcells wired in parallel as opposed to series were identified, including wider selection of band gaps for optimal performance, less sensitivity to spectral variations, and possibly less sensitivity to radiation damage.