Battery bus bar design and laser welding
A battery assembly includes a plurality of battery cells each including a cell tab and a bus bar connected to the cell tabs of adjacent battery cells. The bus bar including a pair of 180 degree bend regions that each define a channel for receiving a respective cell tab and a cut-out region defining an opening having opposing edge portions that allows direct access to the cell tab within the cut-out region. A weld line connects the cell tab to at least one of the opposing edge portions within the cut-out region.
1. A method of connecting a bus bar to a cell tab of a battery cell, comprising:
forming a metallic bus bar having a pair of 180 degree bend regions that each define a channel, the pair of 180 degree bend regions each having a cut-out region defining an opening having opposing edge portions;
inserting a pair of thin plate-like cell tabs of a pair of battery cells into respective channels of the metallic bus bar; and
welding each of the pair of thin plate-like cell tabs to at least one of the opposing edge portions of the respective cut-out regions.
2. The method according to claim 1 , further including clamping the metallic bus bar and pair of thin plate-like cell tabs with a clamping mechanism prior to welding the thin plate-like cell tab to at least one of the opposing edge portions.
3. The method according to claim 1 , wherein the at least one of the opposing edge portions has a coined edge with a step region of reduced thickness.
4. The method according to claim 1 , wherein the at least one of the opposing edge portions has a wedge shaped edge having a tapering thickness.
5. The method according to claim 1 , wherein the step of welding includes a fillet weld.
6. The method according to claim 1 , wherein the step of welding includes a butt weld.
7. The method according to claim 1 , wherein the opposing edge portions have differing heights and the one of the opposing edge portions has a height that is shorter than the other of the opposing edge portions.
8. The method according to claim 1 , wherein the pair of thin plate-like cell tabs extend above the one of the opposing edge portions.
9. The method according to claim 1 , wherein the step of welding includes the use of an oscillating laser welder.