Secondary battery device and secondary battery system

According to an embodiment, a secondary battery device comprises an outer case (24) and a battery cell (23). The outer case has: a hermetic battery housing chamber (24a) formed thereinside; a refrigerant inlet (21) for supplying a liquid refrigerant (27) having insulation properties to the battery housing chamber; and a refrigerant outlet (22) for allowing the liquid refrigerant to flow out of the battery housing chamber. The battery cell has an electrode terminal, is provided inside the battery housing chamber of the outer case, and is immersed in the liquid refrigerant filled in the battery housing chamber.