Patent ID: 9595745
Date: 2017-03-14
CPC Classifications: H01M,Y02E,Y02T

Claim:
1. A nonaqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a nonaqueous electrolyte solution, the nonaqueous electrolyte secondary battery further comprising a porous heat-resistant layer that is disposed between the separator and at least one electrode from among the positive electrode and the negative electrode, and that is formed on a surface of the separator, wherein the porous heat-resistant layer includes hollow particles consisting of an inorganic material and also includes a binder, and the hollow particles have an average particle diameter of at least 0.50 μm and not more than 0.98 μm; and wherein the hollow particles have a hollowness of from 3% to 30%, where the hollowness of a hollow particle is the ratio of the volume of the hollow portion of the hollow particle to the volume of the hollow particle and is determined by observing a particle cross-section with a scanning electron microscope (SEM), measuring from this cross-sectional SEM image the cross-sectional surface area of the overall particle and the cross-sectional surface area of the hollow portion alone, then carrying out a calculation according to the following formula (1) where R is the radius of an ideal circle having the same surface area as the cross-sectional surface area of the overall particle being measured, and r is the radius of an ideal circle having the same surface area as the cross-sectional surface area of the hollow portion alone.