| 摘要 |
PROBLEM TO BE SOLVED: To enhance uniformity, weighing property and moldability and to provide a positive pellet with high conductivity and electrolyte absorbency by granulating slurry comprising a positive active material, conductor, binder and solvent having a specified ratio of solid content of a specified average particle size in a spray drying process. SOLUTION: The average particle size of the solid of slurry is 10 μm or less, and the content of the solid is 20-50 wt.%. A conductor of graphite or carbon black having an average particle size of 10 μm or less is preferably contained by 3-7 wt.%, and a binder of a copolymer of tetrafluoroethylene and hexafluoropropylene having an average particle size of 0.1-0.5 μm is preferably contained by 1-3 wt.%. A solvent is preferably water or a mixture of water and ethanol, and mixed with other solid contents in a wet process, and pulverized to prepare slurry having an average particle size of 10 μm or less. The conductor and the binder uniformly dispersed in the slurry together with a positive active material develop their functions in a small quantity, granulation is made easy, and globular powder is obtained in a spray dry process. |
