Patent ID: 8551638

Claim:
A battery pack for use in a vehicle comprising: a plurality of battery cells, with each of the battery cells including a main body and a foil cell tab extending from the main body, the plurality of battery cells arranged into a first set, having a plurality of the foil cell tabs in surface contact, and a second set, having a plurality of the foil cell tabs in surface contact; an interconnect having a first leg and a second leg spaced from the first leg, and a bridge connecting the first leg to the second leg; a plurality of first friction welds securing the foil cell tabs of the first set of battery cells together and securing only one of the foil cell tabs of the first set to the first leg; and a plurality of second friction welds securing the foil cell tabs of the second set of battery cells together and securing only one of the foil cell tabs of the second set to the second leg; wherein the foil cell tabs of the first set of battery cells include a plurality of foil relief slots, with each of the foil relief slots extending between a respective pair of the first friction welds, and the foil cell tabs of the second set of battery cells include a plurality of foil relief slots, with each of the foil relief slots of the second set of battery cells extending between a respective pair of the second friction welds; wherein a total thickness of all of the foil cell tabs in the first set of battery cell is equal to a thickness of the first leg of the interconnect.