Patent ID: 6806003
Filing Date: 2004-10-19
Classification: H01M,Y02E

Abstract:
A nonaqueous electrolyte secondary battery comprising:a positive electrode comprising a positive-electrode active material; a negative electrode comprising a particulate negative-electrode active material, the positive-electrode active material and the negative-electrode active material capable of intercalating/deintercalating lithium; and a nonaqueous electrolyte solution; wherein the negative electrode further comprises carbon fibers and carbon flakes disposed in the interstices between the particulate negative electrode active material; wherein the ratio by weight of the carbon fibers to the carbon flakes in the negative electrode is in a range of 0.2 to 100; wherein the carbon fibers are produced by vapor phase deposition; wherein the carbon flakes have a (002) interplanar spacing of less than 0.3360 nm by X-ray diffractometry and a thickness of (002) c-axis crystallites of 100 nm or more and the bulk density of the carbon flakes, as measured by Japanese Industrial Standard K-1469, is 0.4 g/cm3 or less, and the maximum particle size of the carbon flakes, as measured by laser diffraction, is 50 &mgr;m or less; wherein the positive-electrode active material comprises a Li compound oxide and the negative-electrode active material comprises one of a Li compound oxide, an amorphous metal oxide, and a carbonaceous material; and wherein the Li compound oxide of the positive-electrode active material is LiMxOy wherein M is at least one selected from the group consisting of Co, Ni, Mn, Fe, Al, V, and Ti, and the negative-electrode active material comprises the carbonaceous material.