Patent ID: 7927740
Filing Date: 2011-04-19
Classification: H01M,Y02E,Y02P,Y02T

Abstract:
1. A battery pack comprising nonaqueous electrolyte batteries, each comprising: a positive electrode containing a positive electrode current collector, and a positive electrode layer which is formed on both surfaces of the positive electrode current collector and contains a lithium-transition metal oxide having a layered crystal structure; a negative electrode containing a negative electrode current collector, and a negative electrode layer which is formed on both surfaces of the negative electrode current collector and contains a lithium-titanium composite oxide having a spinel structure; and a nonaqueous electrolyte, wherein the positive electrodes and the negative electrodes satisfy the formula (1) given below: where X is a ratio of an available electric capacity of each of the negative electrodes at 25° C. to an available electric capacity of each of the positive electrodes at 25° C., the available electric capacity of each of the positive electrodes is an electric capacity obtained by charging under a constant current of 0.2 C to reach 4.25 V, followed by discharging under a constant current of 0.2 C to reach 3.5 V, and the available electric capacity of each of the negative electrodes is an electric capacity obtained by charging under a constant current of 0.2 C to reach 1.0 V, followed by discharging under a constant current of 0.2 C to reach 2.0 V.