NOVELTY - A battery has electrolyte layer containing sulfide solid electrolyte material, between positive electrode active material layer and negative electrode active material layer, and control unit which controls the potential of the negative electrode active material layer. The sulfide solid electrolyte material is in contact with the negative electrode active material. The sulfide solid electrolyte material contains lithium, element chosen from lead, antimony, silicon, germanium, tin, boron, aluminum, gallium, indium, titanium, zirconium, vanadium, niobium and phosphorus and sulfur.    USE - Battery. Uses include but are not limited to personal computer, video camera, mobile telephone, communication apparatus, motor vehicle, electric vehicle and hybrid vehicle.    ADVANTAGE - The battery has high charge-discharge efficiency and capacity.    DETAILED DESCRIPTION - A battery has positive electrode active material layer containing positive electrode active material, negative electrode active material layer containing negative electrode active material, electrolyte layer containing sulfide solid electrolyte material, formed between the positive electrode active material layer and the negative electrode active material layer, and control unit which controls the potential of the negative electrode active material layer, such that potential remains at or less than the potential generated by the reductive decomposition of the sulfide solid electrolyte material. The sulfide solid electrolyte material is in contact with the negative electrode active material. The sulfide solid electrolyte material contains lithium, element chosen from lead, antimony, silicon, germanium, tin, boron, aluminum, gallium, indium, titanium, zirconium, vanadium, niobium and phosphorus, and sulfur, and has peak at 29.58 degrees plus minus 0.50 degrees in X-ray diffraction measurement using the CuK- alpha line. The ratio of diffraction intensity at peak 27.33 degrees plus minus 0.50 degrees and diffraction intensity at peak 29.58 degrees plus minus 0.50 degrees is less than 0.50. The operating potential of the negative electrode active material is more than the potential generated by reductive decomposition of the sulfide solid electrolyte material, and lower than 0.62 V.