| 摘要 |
PROBLEM TO BE SOLVED: To propose a secondary battery in which a current breaking mechanism is able to operate appropriately.SOLUTION: A secondary battery 100 proposed here is, pertaining to a cathode active material layer 223, such that an average grain size D1 of a cathode active material particle 610b included in an internal region 225b from a cathode current collector 221 to 1/2A of a depth A of the cathode active material layer 223 is 6 μm or less, and an average gain size D2 of a cathode active material particle 610a included in a surface region 225a from the surface to 1/5A of the depth A of the cathode active material layer 223 is 1.2≤(D2/D1)≤4 relative to the average grain size D1 of the internal region 225b. Furthermore, a polar plate pore size of the surface region 225a is 0.5 μm or larger. Meanwhile, a particulate porosity of the cathode active material particle 610a included in the surface region 225a is smaller than a particulate porosity of the cathode active material particle 610b included in the internal region 225b. |
