Secondary battery, battery pack, electronic apparatus, electric tool, electric vehicle, and power storage system

Abstract

The invention provides a ssecondary battery, a battery pack, an electronic apparatus, an electric tool, an electric vehicle and a power storage system. The secondary battery including: spirally wound electrode body in which positive electrode and negative electrode are laminated via separator and spirally wound, wherein the positive electrode includes an inner circumference side positive electrode active material layer and an outer circumference side positive electrode active material layer while including a single side active material layer formation region, the ratio A / (A+B) of an area density A of the inner circumference side positive electrode active material layer and an area density B of the outer circumference side positive electrode active material layer, an inner diameter C of the coil opening portion, and the ratio D / E of a thickness D of the positive electrode and a thickness E of the positive electrode collector satisfy the relationship expressed in Formula 1, and a length F of the single side active material layer formation region satisfies the relationship expressed in Formula 2.

Description

technical field [0001] The present invention relates to a secondary battery including a spirally wound electrode body in which a positive electrode and a negative electrode are laminated and spirally wound via a separator, and to a battery pack, electronic equipment, electric tool, Electric vehicles and power storage systems. Background technique [0002] In recent years, electronic devices represented by mobile terminal devices and the like have been popularized, and such devices are required to be further miniaturized, lightweight, and have a longer service life. Therefore, efforts have been made to develop batteries, especially secondary batteries that are small, light, and capable of obtaining high energy density as power sources. In addition, by means of secondary batteries, applications for larger sizes such as for automobiles are also being considered, and wide applications for other purposes are also being considered. [0003] As a secondary battery, the use of var...

AI Technical Summary

Problems solved by technology

[0006] However, if the thickness of the positive electrode active material layer is increased, the flexibility of the positive electrode active material layer will be reduced

Therefore, if the positive electrode is helically wound together with the negative electrode or the like around a coil core rod when producing the spirally wound electrode body, the positive electrode becomes easily broken near the center where the radius of curvature is small

Images