A solid electrolyte battery having improved energy density and safety, the solid
electrolyte battery incorporating a positive electrode; a negative electrode disposed
opposite to the positive electrode; a separator disposed between the positive electrode
and the negative electrode; and solid electrolytes each of which is disposed between
the positive electrode and the separator and between the separator and the negative
electrode, wherein the separator is constituted by a polyolefin porous film, the
polyolefin porous film has a thickness satisfying a range not greater than 5 m
nor greater than 15 m and a volume porosity satisfying a range not less
than 25% nor greater than 60%, and the impedance in the solid electrolyte battery
is greater than the impedance realized at the room temperature when the temperature
of the solid electrolyte battery satisfies a range not less than 100 C. nor
greater than 160 C.