BIPOLAR ALL-SOLID-STATE SODIUM ION SECONDARY BATTERY

Provided is a bipolar all-solid-state sodium ion secondary battery that can increase the voltage without impairing safety. A bipolar all-solid-state sodium ion secondary battery includes: a plurality of all-solid-state sodium ion secondary batteries in each of which a positive electrode layer capable of absorbing and releasing sodium, a solid electrolyte layer made of a sodium ion-conductive oxide, and a negative electrode layer capable of absorbing and releasing sodium are laid one upon another in this order; and a current collector layer provided between the positive electrode layer of each of the plurality of all-solid-state sodium ion secondary batteries and the negative electrode layer of the adjacent all-solid-state sodium ion secondary battery and shared by the positive electrode layer and the negative electrode layer