Secondary battery

Abstract

Secondary batteries are described, the batteries comprising a positive electrode layer, a negative electrode layer and an insulating layer. The insulating layer is located between the positive electrode layer and the negative electrode layer; the thickness of the positive electrode layer is about 10-200 mm; the thickness of the negative electrode layer is 5-150 mm; and the secondary battery meets the following condition: 20%≤a−(b/20)×5%≤35%; where the porosity of the insulating layer is a; and the thickness of the positive electrode layer is b mm. According to the secondary battery, the impedance of the secondary battery can be obviously reduced, and the capacity retention rate of the battery is increased in the long-term cycle process.

Dependencies are inferred from the claim text.