In order to enhance reliability of a battery against bending or twisting in particular, at least one cell group comprising 4 unit cells is formed on a flexible substrate. The cell group has a rectangular shape, and is divided into the 4 unit cells by strip-shaped portions arranged along 2 diagonal lines...http://www.google.es/patents/US7288340?utm_source=gb-gplus-sharePatente US7288340 - Integrated battery
