Patent ID: 8586266

Claim:
A producing method for a solid electrolyte multilayer membrane comprising the steps of: (A) forming a layered casting membrane by casting plural dopes from at least one casting die onto a moving support, each of said dopes containing a solid electrolyte and an organic solvent and having different composition; (B) peeling said layered casting membrane from said support as a layered membrane containing said organic solvent; (C) contacting at least one of: said casting membrane on said support and said layered membrane peeled from the support with a liquid which is a poor solvent of said solid electrolyte and having a lower boiling point than said organic solvent, to replace said organic solvent in said casting membrane or said layered membrane with said liquid; and (D) drying said layered membrane to form a solid electrolyte multilayer membrane, wherein said liquid includes a first liquid stored in a first liquid bath and a second liquid stored in a second liquid bath provided downstream from said first liquid bath, and said step (C) is conducted in each of said first and second liquid baths, and wherein said second liquid has a lower boiling point than said first liquid.