GB1442053A - Method of and apparatus for making intercell connections in electric storage batteries - Google Patents

Abstract

1442053 Welding by pressure GENERAL MOTORS CORP 24 Oct 1974 [23 Nov 1973 (2)] 46018/74 Heading B3R [Also in Division H1] Apparatus and method of making liquidtight connections between plate groups of adjacent battery cells via an aperture of a non- conductive intercell-partition, the plate groups having connector straps with upstanding lugs arranged to face each other across the aperture, comprises casting the lugs from a hypoeutectic Pb-Sb alloy containing at least 2% by weight of Sb, clamping the lugs on opposite sides of the partition to overlie the aperture and simultaneously applying pressure to the overlying parts of the lugs to extrude alloy into the aperture from each side to form a contact area between extrusions lying approx. mid-way through the aperture and comprising 15-75% of the aperture area, while maintaining the clamping and extrusion pressures on the lugs, passing current through the extrusions in gradually increasing amounts to firstly soften them, then melting the Sb-rich phase of the alloy and finally the Sb-lean phase of the alloy, a store of rapidly expandable potential energy being maintained behind the electrodes and allowing this to cause flow of the Sb-rich phase from near the centre of the contact area to the wall of the aperture prior to melting of the Sb-lean phase, and allowing the weld to cool while maintaining the clamping and extrusion forces on the lugs. During the welding operation an increasing clamping force on the lugs and a decreasing force on the extrusion is effected. In apparatus as shown the lugs and partition assembly may be seen at the bottom of the Figure and the extrusion is effected by 2 substantially cylindrical electrodes 6. The lug clamping means comprise pads 32 of high density polyurethane and are arranged around the electrodes. The compression of the polyurethane provides the variable forces referred to above. The electrodes and lug clamps are held in holders 8 which are in turn held in slides 10. The slides are moved via pivoted arms 16 which are held together at toggle 23. Force from an hydraulic system, not shown, may be applied at the toggle to move the electrodes 6 together through the linkages. Each arm 16 contains a spring 26 which is "locked up" by the force applied to the toggle 23 and which provides the rapidly expandable energy to the electrodes 6 as discussed above.