A battery configured as a plurality of battery cells for an electric vehicle with one board for supplying electric power to an electric motor. Each battery cell is provided with positive and negative electrodes on the side of the board. The board is provided with a plurality of cell connecting parts for transmitting cell information of each battery cell corresponding to each electrode. Sensor wiring connects each electrode and each cell connecting part. Wiring is formed are arranged over the board that radiates heat via an insulating adhesive. A heating element is mounted on a first heat-conduction member formed on a top face of the uppermost wiring board. A second heat-conduction member is formed on the downside of the lowermost wiring board. The first heat-conduction member and the second heat-conduction member are touched via a third heat-conduction member arranged in a through hole bored through each wiring board.