A piezoelectric ceramic composition including three components, PbO3, PbTiO3, and PbZrO3, and having a basic composition formula of PbxZryTizO3, where 0. When charging from an external source is started, the control device causes the first voltage step-up converter to perform a rectifying operation for supplying electric current from the charging line to the bus in a case where a voltage of the bus is lower than a voltage of the charging line, and causes the first voltage step-up converter to connect the bus and the second battery. This applied pressure flexes the substrate to reduce in-plane stresses, wherein removal of the applied pressure after deposition of the barrier film modifies the in-film stress for the thin-film.