| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery which enables the improvement of the long-term reliability without affecting the composition of a negative electrode active material or the normal control of a battery.SOLUTION: A lithium ion secondary battery comprises: an electrode group 4. The electrode group is arranged by putting together a positive electrode 41 having a positive electrode mixture layer 41b, and a negative electrode 42 having a negative electrode mixture layer 42b so that separators 43 and 44 are arranged between the positive and negative electrodes, and each edge 42e of the negative electrode mixture layer 42b in its widthwise direction protrudes from the corresponding edge 41e of the positive electrode mixture layer 41b in its widthwise direction, and winding them in a planular form. The lithium ion secondary battery further comprises a pair of annular members 7 elastically deformed to expand in a radial direction, and overlaid on the edges 41e on the outer periphery of the electrode group 4.</p> |
