Patent ID: 9257728
Filing Date: 2016-02-09
CPC Classification: H01M,Y02E,Y02P

Claim Text:
1. A battery pack comprising a plurality of battery cells, a plurality of bus bars, a plurality of safety valves, and a discharge duct, each of the battery cells being covered with an exterior case having a rectangular parallelepiped shape, each of the battery cells having a positive electrode terminal and a negative electrode terminal, the positive electrode terminal and the negative electrode terminal extending from the exterior case, and the battery cells being connected in series through the bus bars to make a series connection structure, wherein the battery cells are divided into a plurality of stacked groups so that the battery cells are stacked in each of the battery stacked groups along a thickness direction of the exterior case of each of the battery cells and all the battery cells are electrically connected in series by the bus bars, one stacked group has a smaller number of the battery cells than the number of the battery cells in the other stacked group, and the stacked groups arranged in a battery case make a stair structure, the positive electrode terminal of the battery cell positioned at one end of the battery cells connected in series in the series connection structure is arranged adjacent to the stair structure, the stair structure has a lower step part and a higher step part formed in the thickness direction along which the battery cells are stacked, with a control board being arranged on the lower step part of the stair structure, and devices mounted on the control board detect a state of each of the battery cells, a power board and the control board are mounted on a single board, the power board being arranged outside of the stair structure, the power board having power elements mounted thereon, and the battery cells are connected in series through a voltage detection terminal of the battery pack, the voltage detection terminal being electrically connected to the single board on which the control board and the power board are mounted.