| abstract |
A case having an electrode group including a positive electrode and a negative electrode, an electrolyte impregnated into the electrode group, a container having an opening and a sealing plate covering the opening, and at least one insulating member, wherein the electrolyte includes a molten salt , The molten salt comprises a cation and an anion, the cation comprises a sodium ion and an organic cation, and the insulating member is made of a material not containing any fluorine atom. |