Patent ID: 8590768

Claim:
A method of forming a solid-state weld between a first metal workpiece and a second metal workpiece, the first metal workpiece being a battery cell tab and the second metal workpiece being aluminum, copper, aluminum alloy, or copper alloy, the second metal workpiece being thicker than the battery cell tab, the method comprising: preparing an assembly of at least two battery cell tabs and the second metal workpiece such that one of the battery cell tabs is placed between the other battery cell tab and the second metal workpiece; selecting a reactive material, in a form to be placed between and in contact with a first joining surface of the first metal workpiece and a first joining surface of the second metal workpiece, the reactive material being selected to react with at least the first joining surface of the first metal workpiece upon being heated to a temperature below the solidus temperature of the first metal workpiece to form a liquid-containing reaction product comprising the reactive material and the first metal, wherein the first metal workpiece and the second metal workpiece with their respective first joining surfaces are face-to-face separated by the reactive material, the amount of reactive material being predetermined to consume a specified amount of one or both workpieces in forming the reaction product in the assembly; pressing the assembly at a first pressure level so that the facing first joining surfaces engage the reactive material, and heating the reactive material for a predetermined time to form the reaction product and consume portions of the facing workpieces; forcing substantially all formed reaction product out from between the joining surfaces; and after forcing substantially all formed reaction product out from between the joining surfaces, holding the first joining surfaces against each other until a solid-state welded joint is formed between the first joining surfaces.