A battery of the present disclosure includes a first solid-state battery cell and a buffer layer. The first solid-state battery cell includes a positive electrode, a negative electrode and a solid electrolyte layer located between the positive electrode and the negative electrode. The positive electrode or the negative electrode has a current collector. The buffer layer is in contact with a face of the current collector opposite to the solid electrolyte layer. The buffer layer includes a thermally expandable material and a conductive resin.