NOVELTY - Solid polymer electrolyte-active substance comprises at least a polymer with a microporous structure and a metal salt, where: the solid polymer electrolyte comprises a solid-like polymer component and a solid-like lithium salt component distributed within the solid-like polymer component; and a liquid-like lithium salt component, which is arranged in at least one portion of the microporous structure.    USE - The solid polymer electrolyte-active substance is useful for producing the solid polymer electrolyte-foil, which is useful in electrochemical battery device (all claimed).    ADVANTAGE - The solid polymer electrolyte-active substance almost without a liquid component, exhibits: high ionic conductivity even at high operating pressures; and high mechanical strength.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) an electrochemical battery based on the solid polymer electrolyte, comprising either at least an arrangement of a first eliminator electrode, an anode, a first separator, an electrolyte, a second separator, a cathode and a second eliminator electrode, or at least an arrangement of a first eliminator electrode, an anode, an electrolyte, a cathode and a second eliminator electrode, where the solid polymer electrolyte foil is used as solid polymer electrolyte;    (2) process for producing the solid polymer electrolyte-foil for electrochemical battery device from the solid polymer electrolyte-active agent, comprising dissolving the solid-like polymer component in a solvent, dissolving a predetermined amount of the solid-like lithium salt component in the dissolved solid-like polymer component, processing the obtained solution to a thin-film, vaporizing the solvent to obtain dry thin-film, which produces a microporous structure in the thin-film and introducing a liquid-like lithium salt component that is formed from a lithium salt dissolved in a solvent, into the thin-film, where the liquid-like lithium salt component is filled at the microporous structure of the thin-film; and    (3) the solid polymer electrolyte-foil, obtained by the above process.