Patent ID: 8637177

Claim:
An electrochemical device comprising a positive electrode, a negative electrode, a nonaqueous electrolyte, and a separator, wherein the separator comprises a porous layer (I) composed of a microporous film composed predominantly of a thermoplastic resin and a porous layer (II) containing a filler having a heat-resistant temperature of 150° C. or higher as the main component, the porous layer (II) has a thickness of 2 μm or more, the filler having a heat-resistant temperature of 150° C. or higher contained in the porous layer (II) makes up 70 vol % or more of a total volume of components of the porous layer (II), the negative electrode contains graphite having an R value of 0.1 to 0.5 and d 002 of 0.338 nm or less as a negative electrode active material, where the R value is a ratio of a peak intensity at 1360 cm −1 to a peak intensity at 1580 cm −1 in an argon ion laser Raman spectrum and the d 002 is a lattice spacing between 002 planes, a ratio of the graphite to the negative electrode active material is 30 mass % or more, a surface of a negative electrode mixture layer has an arithmetic mean roughness of 0.7 μm or more, and the nonaqueous electrolyte contains a dinitrile compound or acid anhydride.