ELECTROLYTE SOLUTION, ELECTROCHEMICAL DEVICE, LITHIUM ION SECONDARY BATTERY AND MODULE

An electrolyte solution containing a solvent. The solvent contains a compound (1) represented by the following formula (1), wherein R, R, R, and Rare the same as or different from each other, and are each —H, —F, —CH, or —CF; at least one of R, R, R, or Ris —F or —CF; and at least one of R, R, R, or Ris —CH, and a compound (2) represented by the following formula (2), wherein Ris a C1-C5 linear or branched alkyl or alkoxy group optionally containing an ether bond; Ris a C1-C5 linear or branched alkyl group optionally containing an ether bond; and at least one of Ror Rcontains a fluorine atom. Also disclosed is an electrochemical device including the electrolyte solution, a lithium-ion secondary battery including the electrolyte solution and a module including the electrochemical device.