Binder composition for lithium-ion secondary battery electrode

Abstract

The present invention relates to a binder composition for lithium-ion secondary battery electrodes. Recently, there is a need for a lithium-ion secondary battery which has the excellent property of accommodating an abnormal situation so that in cases when the battery has heated up abnormally or is in an abnormally high-temperature environment, the battery can lower the charge/discharge performance thereof. The present invention solves the above-mentioned problem by using, as a binder for electrodes, composite polymer particles obtained by polymerizing, in an aqueous medium, a monomer solution containing a polymer.

1 . A binder composition for a lithium-ion secondary battery electrode, comprising a composite polymer particle obtained by polymerizing a monomer solution containing a polymer in an aqueous medium. 
     
     
         2 . The binder composition for a lithium-ion secondary battery electrode according to  claim 1 , wherein
 the polymer is manufactured by a solution polymerization method,   the monomer solution is obtained by dissolving the polymer in a monomer, and   the composite polymer particle is obtained by subjecting the monomer solution to suspension polymerization or emulsion polymerization in an aqueous medium.   
     
     
         3 . The binder composition for a lithium-ion secondary battery electrode according to  claim 1 , wherein
 the polymer is manufactured by a solution polymerization method,   the monomer solution is obtained by dissolving the polymer in an amount of 5 to 100 parts by weight with respect to 100 parts by weight of a monomer, and   the composite polymer particle is obtained by subjecting the monomer solution to suspension polymerization or emulsion polymerization in an aqueous medium.   
     
     
         4 . The binder composition for a lithium-ion secondary battery electrode according to  claim 2 , wherein the polymer manufactured by the solution polymerization method is an olefin polymer. 
     
     
         5 . The binder composition for a lithium-ion secondary battery electrode according to  claim 2 , wherein the polymer manufactured by the solution polymerization method is a block copolymer. 
     
     
         6 . The binder composition for a lithium-ion secondary battery electrode according to  claim 2 , wherein the polymer manufactured by the solution polymerization method has a melting point in a range of 50° C. to 150° C. 
     
     
         7 . The binder composition for a lithium-ion secondary battery electrode according to  claim 1 , wherein the composite polymer particle has a core-shell structure in which a shell portion containing a polymer having a binding property is further formed on a surface of the composite polymer particle.