Flat-shaped all-solid battery and method for manufacturing same

A method for manufacturing a flat-shaped all-solid battery comprising a battery container constituted by an outer can and a sealing can and a stack which a positive electrode, a solid electrolyte layer, and a negative electrode are stacked to form,

• the method comprising:
• inserting the stack inside of the sealing can on which an annular gasket is installed;
• constituting an assembly by stacking a conductive porous member and the stack, wherein the assembly has the conductive porous member on at least one side of the stack;
• and
• sealing the outer can by covering the assembly with the outer can and crimping the outer can,
• wherein the conductive porous member is disposed between the stack and an inner bottom surface of the outer can and/or between the stack and an inner bottom surface of the sealing can,
• wherein the conductive porous member is a conductive porous sheet constituted by a molded body of expandable graphite and having flexibility,
• wherein the gasket comprises a bottom surface portion sandwiched between an opening edge of the sealing can and the inner bottom surface of the outer can, and
• wherein before the assembly is covered with the outer can, the assembly is constituted to satisfy −0.25≤a−t≤0.18, where t (mm) represents a height from the inner bottom surface of the sealing can to an end of the bottom surface portion of the gasket, the end being proximate to the outer can, and a (mm) represents a total of thicknesses of the stack and the conductive porous member.