CPC H01M 10/0587 (2013.01) [H01M 4/38 (2013.01); H01M 10/0431 (2013.01); H01M 10/0585 (2013.01); H01M 50/103 (2021.01); H01M 4/134 (2013.01); H01M 10/0525 (2013.01)] | 7 Claims |
1. A secondary battery comprising:
a square battery case; and
a wound electrode body accommodated in the battery case, wherein
the wound electrode body has a positive electrode sheet and a negative electrode sheet at least overlapping with each other to be wound about a winding axis to have a rectangular shape when seen from a winding axis direction,
the wound electrode body has corner parts positioned at four corners of the wound electrode body when seen from the winding axis direction,
the positive electrode sheet has a positive electrode collector and a positive electrode active material layer formed on the positive electrode collector,
the negative electrode sheet has a negative electrode collector and a negative electrode active material layer formed on the negative electrode collector, and
folding grooves are formed along the winding axis direction in at least one of the positive electrode active material layer and the negative electrode active material layer at positions corresponding to the corner parts about the winding axis in the positive electrode sheet and the negative electrode sheet.
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