Case for lithium metal secondary battery, lithium metal secondary battery comprising same, method for manufacturing same

Abstract

Provided is a casing for a lithium metal secondary battery including: a battery casing material; at least one releasable capsule attached at least partially or totally to the inner surface of the casing material to cover the inner surface of the casing material; and a release solution supported in the releasable capsule, wherein the releasable capsule includes a capsule coating film and a capsule inner space surrounded with the capsule coating film, the release solution is supported in the capsule inner space, and the release solution includes a release agent and a solvent. A lithium metal secondary battery including the casing and a method for manufacturing the same are also provided. It is possible to increase releasability of the negative electrode in a lithium metal secondary battery and to improve nail safety by using the releasable capsule according to the present disclosure.

What is claimed is: 
     
         1 . A casing for a lithium metal secondary battery comprising:
 a battery casing material;   at least one releasable capsule attached to an inner surface of the casing material to cover the inner surface of the casing material; and   a release solution contained in the releasable capsule,   wherein the releasable capsule comprises a capsule coating film and a capsule inner space surrounded by the capsule coating film,   the release solution is contained in the capsule inner space, and   the release solution comprises a release agent and a solvent.   
     
     
         2 . The casing for a lithium metal secondary battery according to  claim 1 , wherein the release agent comprises one chose from a vinyl acetate resin, vinyl chloride resin, urethane resin, chlorinated rubber resin, phthalic acid resin, alkyd resin, epoxy resin, phenolic resin, melanin resin, acrylic resin, fluoro-resin, silicone resin, metal acrylate resin, a rosin resin, or a mixture of two or more of thereof. 
     
     
         3 . The casing for a lithium metal secondary battery according to  claim 2 , wherein the release agent comprises the fluoro-resin, where the fluoro-resin comprises one chosen from fluorosilane, perfluoropolyether, fluoroacrylate, perfluoromethacrylate, or a mixture of two or more of thereof. 
     
     
         4 . The casing for a lithium metal secondary battery according to  claim 1 , wherein the releasable capsule comprises a polymer resin as a capsule coating film ingredient, and the capsule coating film is ruptured by a penetration member inserted from an outside of the casing so that the release solution contained in the capsule inner space is discharged. 
     
     
         5 . The casing for a lithium metal secondary battery according to  claim 4 , wherein the polymer resin comprises one chosen from polyolefin, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyethylene naphthalene, or a mixture of two or more of thereof. 
     
     
         6 . The casing for a lithium metal secondary battery according to  claim 1 , wherein the release agent is present in an amount of 0.1-80 wt % based on a total weight of the release solution. 
     
     
         7 . The casing for a lithium metal secondary battery according to  claim 1 , wherein a size of the releasable capsule is 0.1 to 100 μm. 
     
     
         8 . A lithium metal secondary battery comprising:
 a battery casing according to  claim 1 ; and   an electrode assembly contained in the battery casing,   wherein the electrode assembly comprises a negative electrode, a positive electrode and a separator interposed between the negative electrode and the positive electrode, and   the negative electrode includes lithium metal as a negative electrode active material.   
     
     
         9 . A method of preventing a short circuit, comprising:
 penetrating a penetration member through the casing according to  claim 1 , to rupture the capsule coating film   discharging the release agent from the inner part of the capsule; and   attaching the release agent discharged from the inner part of the capsule to a surface of the penetration member to prevent a lithium metal in a lithium metal negative electrode from attaching to the penetration member.   
     
     
         10 . The method according to  claim 9 , wherein the capsule coating film is ruptured under a pressure of 25 psi or more. 
     
     
         11 . The casing for a lithium metal secondary battery according to  claim 1 , wherein the release agent is present in an amount of 20 to 30 wt % based on a total weight of the release solution. 
     
     
         12 . The casing for a lithium metal secondary battery according to  claim 1 , wherein the release agent comprises fluorosilane. 
     
     
         13 . The casing for a lithium metal secondary battery according to  claim 1 , wherein the release agent comprises perfluoropolyether. 
     
     
         14 . The casing for a lithium metal secondary battery according to  claim 1 , wherein the release agent comprises fluoroacrylate. 
     
     
         15 . The casing for a lithium metal secondary battery according to  claim 1 , wherein the release agent comprises perfluoromethacrylate.