| CPC H01M 50/531 (2021.01) [H01M 10/0404 (2013.01); H01M 10/42 (2013.01); H01M 50/10 (2021.01); H01R 43/0221 (2013.01); H05K 3/328 (2013.01)] | 2 Claims |
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1. A battery pack, comprising:
a battery cell from which an electrode tab extends; and
a protection circuit module which is electrically connected to the battery cell, and which has a circuit board and a tab plate formed on one surface of the circuit board and electrically connected to the electrode tab, wherein:
the circuit board has a welding hole that penetrates the circuit board and extends to a first edge of the circuit board such that the welding hole has a second edge that is continuous with the first edge while being laterally recessed from the first edge, the welding hole defining an exposed portion of the tab plate,
the exposed portion of the tab plate overlies the electrode tab and has a through hole for heating the electrode tab, the through hole exposing the electrode tab,
the exposed portion of the tab plate and the electrode tab are electrically connected to each other by laser welding, a plurality of welds being formed by the laser welding at locations that are spaced apart from the through hole,
the plurality of welds include a first welding bead, a second welding bead, a third welding bead, and a fourth welding bead, the first welding bead being at one side of the through hole, the second welding bead being spaced apart from the first welding bead in a first direction, the third welding bead being spaced apart from the first welding bead in a second direction perpendicular to the first direction, the fourth welding bead being spaced apart from the third welding bead in the first direction, and the first to fourth welding beads have the same size, and
the through hole has a perimeter, the entire perimeter of the through hole being free of welds, and none of the first through fourth welding beads touching the perimeter of the through hole.
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