Patent attributes
An electric storage battery including a jelly roll type electrode assembly having a mandrel. The mandrel includes a positive portion, a negative portion and a removable portion. The mandrel can be planar, having two faces with grooves on the positive and negative portions. The grooves are dimensioned to accommodate positive and negative feedthrough pins. The mandrel is welded to the feedthrough pins by using a laser beam incident on the opposite face of the mandrel from the face on which the grooves and pins are located. The laser beam melts the mandrel such that molten mandrel material fills the grooves welding the feedthrough pins in place. Electrodes are wrapped around the mandrel using the removable portion to wind the mandrel. The removable portion can be detached. The mandrel allows tighter wrapping of the jelly roll assembly and increasing battery miniaturization.
