Patent ID: 7060116

Claim:
A method of making a combined battery, the method comprising the steps of: providing a plurality of sealed cells, wherein each of the cells is provided with a battery container made of resin; stacking the plurality of sealed cells adjacent each other; providing two end plates for binding the stacked cells; determining a binding fore equal to or lower than a threshold value at which no more than a predetermined amount of irreversible deformation would be caused in the battery container, the threshold value based on a number and a compressibility of the plurality of cells and stiffness of the battery container; and binding the plurality of sealed cells by two end plates under the binding force, wherein the threshold value is based on a crossing point of the F-S curves of at least one or more expanded cell and remaining compressed cell, wherein the battery container is in a compressed state due to the binding force immediately after assembly of the combined battery, where F represents load applied to unit cell and S represents width of unit cell.