Method of producing electrode
A method of producing an electrode includes preparing a temperature responsive polymer, preparing wet granules by mixing the temperature responsive polymer, a solvent, and active material particles, molding an active material film by sandwiching the wet granules between a first molding tool and a second molding tool, compressing the active material film by sandwiching the active material film between a third molding tool and a fourth molding tool, and disposing the active material film on a surface of a current collector.
1. A method of producing an electrode comprising:
preparing a temperature responsive polymer swelling when the temperature responsive polymer absorbs a solvent at a temperature that is lower than a lower critical solution temperature of the temperature responsive polymer and contracting when the temperature responsive polymer releases the solvent at a temperature that is equal to or higher than the lower critical solution temperature;
preparing wet granules by mixing the temperature responsive polymer, the solvent, and active material particles;
molding an active material film by sandwiching the wet granules between a first molding tool and a second molding tool, the first molding tool being maintained at a temperature that is lower than the lower critical solution temperature, the second molding tool being maintained at a temperature that is equal to or higher than the lower critical solution temperature, the active material film including a first main surface and a second main surface, the first main surface being molded by the first molding tool, and the second main surface being molded by the second molding tool; and
compressing the active material film by sandwiching the active material film between a third molding tool and a fourth molding tool, the third molding tool and the fourth molding tool being maintained at a temperature that is equal to or higher than the lower critical solution temperature; and
disposing the active material film on a surface of a current collector such that the first main surface is positioned on a side of the active material film opposite to the current collector.
2. The method according to claim 1 , wherein all of the first molding tool, the second molding tool, the third molding tool, and the fourth molding tool are rotating rollers.
3. The method according to claim 1 , wherein the temperature responsive polymer includes poly-N-isopropylacrylamide, hydroxypropylcellulose, or polyvinyl methyl ether.
4. The method according to claim 1 , wherein the temperature responsive polymer is poly-N-isopropylacrylamide, and the solvent is water.
5. The method according to claim 1 , wherein the active material particles are graphite particles.
6. The method according to claim 1 , wherein a proportion of the solvent with respect to a solid content of the wet granules is 35 mass % or less.
7. The method according to claim 1 , wherein a proportion of the temperature responsive polymer with respect to a solid content of the wet granules is 0.5 mass % to 2.0 mass %.
8. The method according to claim 1 , wherein a proportion of the active material particles with respect to a solid content of the wet granules is 80 mass % to 99 mass %.
9. A method of producing an electrode comprising:
preparing a temperature responsive polymer swelling when the temperature responsive polymer absorbs a solvent at a temperature that is lower than a lower critical solution temperature of the temperature responsive polymer and contracting when the temperature responsive polymer releases the solvent at a temperature that is equal to or higher than the lower critical solution temperature;
preparing wet granules by mixing the temperature responsive polymer, the solvent, and active material particles;
molding an active material film by sandwiching the wet granules between a first molding tool and a second molding tool, the active material film including a first main surface and a second main surface;
heating the second main surface to a temperature that is equal to or higher than the lower critical solution temperature while maintaining the first main surface at a temperature that is lower than the lower critical solution temperature;
compressing the active material film by sandwiching the active material film between a third molding tool and a fourth molding tool; and
heating the first main surface and the second main surface to a temperature that is equal to or higher than the lower critical solution temperature; and
disposing the active material film on a surface of a current collector such that the first main surface is positioned on a side of the active material film opposite to the current collector.