To provide an electrochemical element which excels in safety, high-temperature storage characteristics and charge characteristics at a low temperature during overcharging.
The electrochemical element includes a separator which has (I) a porous layer constituted of a fine porous film having mainly a thermoplastic resin and (II) a porous layer including a filler with a heat resistant temperature of 150°C or more as the main coomponent; a negative electrode which contains graphite, having an R-value of 0.1-0.5 which is a ratio of peak intensity at 1,360 cm-1 with respect to a peak intensity at 1,580 cm-1 in argon ion laser Raman spectrum, and a surface interval d002 of 002 face of 0.338 nm or less, as a negative electrode active material in which the ratio of graphite is 70 mass% or more, and a nonaqueous electrolytic solution containing at least one kind of compound selected from among sulfonic acid anhydride and sulfonate ester derivative having a specific structure and a dinitrile compound.
YONEDA KEISUKE
YAMASHITA YO
Hideki Miwa