NOVELTY - The power storage device (100) comprises: a positive electrode (101) and a negative electrode (102) facing each other in an exterior body; an electrolyte solution between the positive electrode and the negative electrode; and a protective component having conductivity between the exterior body and the positive electrode, where the electrolyte solution includes an ionic liquid as a solvent. The positive electrode includes a current collector. The protective component is present in contact with the current collector and the exterior body.    USE - The power storage device such as nonaqueous secondary batteries including lithium-ion batteries, lithium-ion capacitors and air cells is useful in the semiconductor industry for electric appliances such as portable information terminals (including mobile phones, smartphones and laptop computers), portable music players, digital cameras and medical equipment and in next-generation clean energy vehicles such as hybrid electric vehicles, electric vehicles and plug-in hybrid electric vehicles.    ADVANTAGE - The power storage device exhibits high degree of safety, increased output and energy density, and improved cycle life, and suppresses the elution of the positive electrode current collector due to contact between different metals and prevents a phenomenon in which the eluted metal of the positive electrode current collector is deposited on the negative electrode and the deposited metal comes in contact with a positive electrode thus preventing internal short-circuit caused by the contact.    DETAILED DESCRIPTION - The power storage device (100) comprises: a positive electrode (101) and a negative electrode (102) facing each other in an exterior body; an electrolyte solution between the positive electrode and the negative electrode; and a protective component having conductivity between the exterior body and the positive electrode, where the electrolyte solution includes an ionic liquid as a solvent. The positive electrode includes a current collector. The protective component is present in contact with the current collector and the exterior body. A part of the exterior body serves as a positive electrode terminal, and is electrically connected to the current collector through the protective component. The protective component having conductivity is arranged between the exterior body and the positive electrode terminal.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic external view of a coin-type power storage device.    Power storage device (100)    Positive electrode (101)    Negative electrode (102)    Gasket. (103)