LITHIUM-ION BATTERY

摘要

In a lithium ion battery provided with a cleavage valve which discharges gas in accordance with an internal pressure rise, and a discharge capacity X of the battery being 30 Ah or more and less than 100 Ah, a positive electrode composite contains a mixed active material of layered lithium nickel manganese cobalt composite oxide (NMC) and spinel lithium manganese oxide (sp-Mn). A density of the positive electrode composite is 2.4 to 2.7 g/cm 3 , an application quantity of the positive electrode composite is 175 to 250 g/cm 2 , and when a weight ratio (NMC/sp-Mn) is defined as Y, a relation of Y<-0.0062X+1.05 is satisfied. Also, a working pressure of the cleavage valve is 1.0 to 5.0 MPa when the discharge capacity X is 30 Ah or more and 40 Ah or less, is 1.0 to 4.0 MPa when the discharge capacity X is more than 40 Ah and 80 Ah or less, and is 1.0 to 3.0 MPa when the discharge capacity X is more than 80 Ah and less than 100 Ah.