US Patent 7740978 Battery pack

The battery pack uses a restraining tool capable of secure restraint despite relatively low rigidity to achieve weight and cost reductions. The battery pack is formed of a plurality of parallel arranged battery modules (2), each consisting of a plurality of cells (5) electrically connected in series and coupled together in one piece with gaps (8) formed therebetween (5, 5), each cell being formed of elements for electromotive force encased in a prismatic case. The restraining tool includes connecting members (4) extending through the gaps (8) at both ends of the parallel arranged battery modules (2) and between two given cells (5, 5).