| abstract |
A safe high-performance lithium secondary cell is provided whereby bulging of a lithium secondary cell during storage at a high temperature, which is particularly problematic when a casing accommodating a cell element is a variable shape casing, is suppressed. n The present invention provides a lithium secondary cell comprising a cell element which comprises a positive electrode, a negative electrode and an electrolyte comprising a non-aqueous solvent and a solute, and a variable shape casing which accommodates the cell element, wherein the cell element contains an additive α, and ΔEadd(AN) is smaller than ΔEsol(AN), where ΔEsol(AN) is the difference represented by Esol(A)−Esol(N), where Esol(N) is the enthalpy of a neutral molecule of the non-aqueous solvent, as obtained by a prescribed calculation method, and Esol(A) is the enthalpy of an anion radical formed by giving one electron to the neutral molecule, and ΔEadd(AN) is the difference represented by Eadd(A)−Eadd(N), where Eadd(N) is the enthalpy of a neutral molecule of the additive α, as obtained by a prescribed calculation method, and Eadd(A) is the enthalpy of an anion radical formed by giving one electron to the neutral molecule. |