Study of the effect of different hole sizes on mechanical strength of wafers for back contact solar cells - Rubén Gutiérrez; Juan Carlos Jimeno Cuesta; Eneko Cereceda; HERMANNS, LUTZ KARL HEINZ; BARREDO EGUSQUIZA, JOSU; FRAILE DE LERMA, ALBERTO (Conference Record Of The Ieee Photovoltaic Specialists Conference, 2012)