LITHIUM ION SECONDARY CELL AND MANUFACTURING METHOD THEREOF

摘要

In a lithium ion secondary cell, an active material layer or a separator of at least one of the positive electrode and the negative electrode holds a porous insulation layer. The surface of the active material layer or the separator holding the porous insulation layer has a first region where a porous insulation layer is formed and a second region where a plurality of discontinuous deficit portions where no porous insulation layer is formed. When an arbitrary reference deficit portion is selected from the deficit portions and an arbitrary circle having an area of the reference deficit portion multiplied by 10 is set on the surface of the active material layer or the separator, the area of the second region contained in the range surrounded by the circle is controlled to be not smaller than 10 µm² and not greater than 100 mm².