摘要 |
A wound electrode group includes an electrode stack that is formed by laminating a strip of positive electrode plate, a strip of negative electrode plate, and a pair of separators interposed therebetween. When the electrode stack is wound, a difference L in length between an inner turn and an adjacent outer turn satisfies L=2tpi+(Wxk), where t is a thickness of the electrode stack, W is a maximum diameter of a cross section of the wound electrode group, and k is a coefficient that is preset in accordance with expansion coefficients of active materials of the positive and negative electrode plates and is within a range from 0.005 to 0.05.
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