Polymer gel electrolyte, lithium ion battery and method for producing same

1. A method for producing a lithium ion battery, comprising:

a step (A) of housing an electrode group comprising a positive electrode, a negative electrode and a separator in an outer package;

a step (B) of injecting a pre-gel solution, which is a precursor of a polymer gel electrolyte, within the outer package, to impregnate the electrode group with the pre-gel solution to form a pre-battery;

a step (C) of charging the pre-battery while keeping the state of the pre-gel solution; and

a step (E) of gelatinizing the pre-gel solution by maintaining the pre-battery charged under warm temperature to form the polymer gel electrolyte,

wherein the pre-gel solution comprises at least a lithium salt, an aprotic solvent and a polymer,

an amorphous polymer layer derived from the polymer is formed on a surface of an electrode active material, and

the polymer gel electrolyte comprises a crosslinked body of the polymer that is formed on the amorphous polymer layer.

2. The method for producing a lithium ion battery according to claim 1 , further comprising, between the step (C) and the step (E), a step (D) of re-impregnating the electrode group with the pre-gel solution of the pre-battery.

3. The method according to claim 1 , wherein the polymer is a polymer having a polymerizable functional group.

4. The method according to claim 1 , wherein the polymer is a (meth)acrylate polymer.

5. The method according to claim 1 , wherein an SEI (Solid Electrolyte Interface) is formed between the surface of the electrode active material and the amorphous polymer layer.

6. The method according to claim 1 , wherein the pre-gel solution contains a cyclic carbonate.

7. The method according to claim 1 , wherein the pre-gel solution contains an electrode surface coating film-forming agent (SEI-forming agent).

8. The method according to claim 7 , wherein the electrode surface coating film-forming agent (SEI-forming agent) is at least one selected from a cyclic unsaturated sultone compound, a carbonate, a cyclic disulfonate and a linear disulfonate.

9. The method according to claim 1 ,

wherein the temperature during charging in the step (C) is in a range of 10° C. to 30° C., and

in the step (E), the charge state of the pre-battery is maintained under temperature conditions of 35° C. or more and 60° C. or less.