METHOD OF MIXING ACTIVE MATERIAL FOR ELECTRODE

PROBLEM TO BE SOLVED: To improve coat density by mixing an active material and a conductive auxiliary material in a mixing time. SOLUTION: This method of mixing an active material for an electrode comprises a process for forming a hill by dropping particles 12 of the active material 11 to be applied onto a collector of an electrode from above onto a horizontal plate 14, a process for measuring an angle of repose θ as an angle between the foot 16 of the hill 15 and the horizontal plate 14, a process for determining a mixing time of the materials with respect to the obtained angle of repose, and a process for mixing the active material and the conductive auxiliary material by the determined mixing time. In the process for determining the mixing time, the mixing time is determined, for example, to be one hour when the angle of repose is less than 50 deg., and two and half hours when the angle of repose is 50 deg. or more, whereby preventing the shortage in mixing, and the impairing of the productivity caused by an excess mixing time.