Patent ID: 6569557
Filing Date: 2003-05-27
Classification: H01M,Y02E,Y02P,Y02T

Abstract:
A lithium secondary battery comprising:an internal electrode body including a positive electrode, a negative electrode, and a separator, the positive electrode and the negative electrode being wound or laminated via the separator, a plurality of current collecting portions welded directly to said positive electrode, a plurality of current collecting portions welded directly to said negative electrode, and an organic electrolyte, the positive electrode comprising a conductive positive electrode collector and a positive electrode coating, the positive electrode coating consisting essentially of positive electrode active material, acetylene black and binder, the negative electrode comprising a conductive negative electrode collector and a negative electrode coating, the negative electrode coating comprising at least one material selected from the group consisting of soft carbon, hard carbon, artificial graphite and natural graphite, wherein the positive electrode active material satisfies the following relation between the average particle diameter R (&mgr;m) and the specific surface area S (m2/g): 6&lE;RÃ—S50, â€ƒwherein R is in the range of from 11 to 50 &mgr;m, and the acetylene black is present in the positive electrode coating in an amount which satisfies the following relation with the specific surface area of the positive electrode active material: S&lE;W&lE;S+5(W&lE;10) â€ƒwherein W is the amount of the acetylene black in the positive electrode coating, expressed in % by weight based on the amount of the positive electrode coating, and S has the same definition as given above and is expressed in m2/g, said battery having a capacity of at least 2 Ah and an internal resistance of less than or equal to 4 milli-ohms.