US Patent 7838762 Solar cell

A solar cell comprises a substrate configured to have a plurality of via holes and a first conductive type, an emitter layer placed in the substrate and configured to have a second conductive type opposite to the first conductive type, a plurality of first electrodes electrically coupled to the emitter layer, a plurality of current collectors electrically coupled to the first electrodes through the plurality of via holes, and a plurality of second electrodes electrically coupled to the substrate. The plurality of via holes comprises at least two via holes having different angles.