| 摘要 |
PURPOSE:To prevent internal shortcircuiting generated, when active material having slipped off from the electrode breaks the separator, by interposing a porous film between the separator and the electrode. CONSTITUTION:In a battery can in cylindrical form, a band-shaped positive electrode 2 and negative electrode 1 are wound in laminate while a separator 3 is interposed, and thereby a spiral electrode is formed, wherein a separator protecting film 4 having through holes is interposed between the separator 3 and negative electrode 1. This film 4 prevents the separator 3 from being broken by the active material which slips off at manufacturing and is included between the separator 3 and negative electrode 1, and also generation of internal shortcircuiting can be suppressed. Because the ion transmissivity of the film 4 is secured by the through holes, provision of the film 4 does not enlarge the internal resistance of the battery. Therefore, the frequency of shortcircuit generation can be reduced while high energy density is maintained. |
