Patent ID: 7304453
Filing Date: 2007-12-04
Classification: A61B,G01T,H01M,Y02E

Abstract:
1. A method for assembling a battery pack of specified capacity from a plurality of cells assembled to planar circuit boards in order to comprise at least two substantially identical planar cell cards, comprising the steps of: dividing the specified capacity by a nominal battery module capacity, to determine a desired number of parallel modules to be provided, dividing the nominal battery module capacity by a nominal cell card capacity, to determine the number of cell cards required in each module, dividing the nominal cell card capacity by the cell capacity, to determine the number of cells to be provided in each cell card, providing a number of planar circuit boards of fire-resistant material equal to the required number of cell cards, assembling the cells to the planar circuit boards so as to provide the planar cell cards, said cells being generally elongated cylindrical members, having terminals at their opposed ends, and being arranged on said cell cards and connected end-to-end to form at least two series-connected linear arrays on each card, said arrays being disposed physically parallel to one another on each card so as to define at least two rows of side-by-side cells, with the axes of said cylindrical cells parallel to the plane of said planar circuit boards, assembling the at least two substantially identical cell cards to comprise the desired number of cells in a suitable series/parallel circuit, each cell card having positive and negative terminals, by arranging the planar cell cards parallel to one another, and connecting the at least two cell cards in parallel by connecting elongated bus bars to the positive and negative terminals of each card so as to comprise the battery module(s), whereby the bus bars extend orthogonally to the parallel planar cell cards and make electrical and mechanical connection between the cell cards, and whereby passages for ventilating air and/or hot gases resulting from damage to one or more cells are formed between the cylindrical cells and the planar cell cards, each said cell card comprising cell monitoring circuitry for monitoring the condition of the cells on the cell card, and for disconnecting the cell card from the elongated bus bars in response to detection of a fault, connecting the modules(s) in parallel to obtain the specified battery pack capacity and in series to obtain the specified battery pack voltage, and disposing the assembled modules in a closely-fitting enclosure so that the cell cards effectively subdivide the interior of the enclosure, limiting the spread of fire within the enclosure; and wherein the cell cards are notched at their ends to cooperate with said enclosure so as to define ducts extending transverse to said cell cards in communication with said passages between said cylindrical cells and said cell cards for ventilating air and/or hot gases.