| 摘要 |
PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery arranged to suppress the occurrence of short circuit between positive and negative electrodes owing to the precipitation of metal on a negative electrode mixture layer at a high temperature after initial charging.SOLUTION: A lithium ion secondary battery comprises: an electrode structure having a positive electrode plate, a separator and a negative electrode plate laminated together and wound; and an electrolytic solution including lithium ions. The positive electrode plate has a positive electrode outermost peripheral part which forms its own outermost periphery. The negative electrode plate has a first negative electrode part located outside the positive electrode outermost peripheral part in a radial direction thereof. The separator has an outside separator part which is opposed to the first negative electrode part, and adjacent to a first outside mixture layer part on its outside in a radial direction thereof. The negative electrode plate has a piece of negative electrode foil, and two negative electrode mixture layers. The lithium ion secondary battery further comprises a first migration-preventing part for preventing lithium ions from migrating from the outside separator part into the first outside mixture layer part, provided that in the first negative electrode part, a portion of the negative electrode mixture layer which is formed outside the piece of negative electrode foil in the radial direction thereof and is adjacent to the outside separator part is defined as the first outside mixture layer part. |
