Bipolar all-solid-state sodium ion secondary battery

A bipolar all-solid-state sodium ion secondary battery comprising:

• 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;
• 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;
• and
• a first metal film provided between the positive electrode layer and the current collector layer and/or a second metal film provided between the negative electrode layer and the current collector layer.