NOVELTY - A lithium solid secondary battery system (20) has lithium solid secondary battery (10) having a solid electrolyte layer between negative electrode having negative electrode active material layer, and positive electrode having positive electrode active material layer, and positive electrode collector. The battery has an overdischarge processing portion (11) discharged until state-of-charge (SOC) of the lithium solid secondary battery is less than 0%. The negative electrode active material layer contains a negative electrode active material and a sulfide solid electrolyte material.    USE - Lithium solid secondary battery system. Uses include but are not limited to power supply for personal computer, video camera, mobile telephone, communication apparatus, electric vehicle, hybrid vehicle, etc.    ADVANTAGE - The lithium solid secondary battery system has high output characteristics.    DETAILED DESCRIPTION - A lithium solid secondary battery system has a lithium solid secondary battery having a solid electrolyte layer formed between a negative electrode having a negative electrode active material layer, and a positive electrode having a positive electrode active material layer, and a positive electrode collector. The battery has an overdischarge processing portion discharged until state-of-charge (SOC) of the lithium solid secondary battery is less than 0%. The negative electrode active material layer contains a negative electrode active material and a sulfide solid electrolyte material containing lithium, metal (A) chosen from phosphorus, sulfur, germanium, aluminum and boron, and sulfur, preferably phosphorus, and having an ortho composition. The negative electrode collector comprises a metal.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of lithium solid secondary battery system.    Lithium solid secondary battery (10)    Overdischarge processing portion (11)    Switch portion (12a,12b)    Lithium solid secondary battery system (20)