A process for fabrication of a battery that includes providing a colloidal suspension of particles conducting lithium ions and providing two conducting substrates as battery current collectors, at least one surface of the conducting substrates being at least partially coated with one of a cathode film and an anode film, and depositing an electrolyte film by electrophoresis, from a suspension of electrolyte material particles, on at least one of said anode film, said cathode film and said conducting substrates.