LITHIUM SECONDARY BATTERY

摘要

The present invention provides a lithium secondary battery with excellent stability under extremely-high temperatures. Between a positive electrode including a positive pole lead and a negative electrode including a negative pole lead, a separator is placed. The positive pole lead and the negative pole lead are overlapped to protrude in the same direction and are wound in a vortex shape to form a planar wound electrode. Nonaqueous electrolyte is sealed in a battery case which has a hollow pillar shape and a thickness equal to or greater than 40 mm. The separator includes a porous layer (I) mainly made of thermoplastic resin and a porous layer (II) mainly made of filler having a heat-resisting temperature equal to or higher than 150°C. The thickness of the porous layer (II) is equal to or smaller than 8 μm. In the planar wound electrode, a cross section from which the positive electrode and the negative electrode protrude and two lateral surfaces which face each other and are wider than other surfaces are fixed by a tape containing a resin which is not melted at the temperature which is equal to or smaller than a shutdown temperature.