Patent ID: 8592081

Claim:
A nonaqueous secondary battery, comprising: a positive electrode; a negative electrode; and a nonaqueous electrolyte solution, the nonaqueous electrolyte solution containing as a flame retardant a compound of the general formula (I): wherein R 1 and R 2 , which are the same or different, each represents a group that is selected from a hydrogen atom, a lower alkyl, lower alkenyl, lower alkoxy, lower alkoxycarbonyl, lower alkylcarbonyl, lower cycloalkyl or aryl group, and that may have a substituent, or R 1 and R 2 taken together are a methylene group that may have a substituent, or R 1 and R 2 taken together form a ring structure containing a nitrogen atom to which R 1 and R 2 are attached, the ring structure being a five-membered or six-membered hydrocarbon ring that may have one or two oxo groups, or a five-membered or six-membered heterocycle that may further contain a nitrogen atom; n is 1; R 3 and R 4 are as defined for R 1 and R 2 ; wherein percentage of the compound of the general formula (I) to be blended in the nonaqueous electrolyte solution is in the range of 10% to 40% by volume fraction; and wherein the compound of the general formula (I) is a compound that produces inert gas containing CO2 or CO as a main component when heated at a temperature higher than its decomposition temperature.