| abstract |
A lithium ion secondary battery includes a positive electrode, a negative electrode, a porous heat-resistant layer, and a nonaqueous electrolyte. The positive and negative electrodes reversibly absorb and release lithium ions, respectively. The porous heat-resistant layer is provided between the positive electrode and the negative electrode and includes a metal oxide as filler. The nonaqueous electrolyte is impregnated into the porous heat-resistant layer and exists between the positive electrode and the negative electrode. The filler of the porous heat-resistant layer has a particle diameter of 0.1 μm or more and 5.0 μm or less, D10 in particle size distribution measurement of 0.2 μm or more and 0.6 μm or less, and a mode diameter of 0.80 μm or more and 1.25 μm or less. |