Degree-of-dispersion inspecting apparatus for particles of electricity storage material in electricity storage device

A degree-of-dispersion inspecting apparatus (1) accurately quantifies the degree of dispersion of particles of an electricity storage material based on in-plane uniformity (±) and void size uniformity (²), which are obtained from an image of a coating film of the electricity storage material. The in-plane uniformity (±) is a macroscopic value based on the ratio of voids between the particles in the electricity storage material, and the void size uniformity (²) is a microscopic value based on values equivalent to the sizes of the voids between the particles in the electricity storage material. This allows the degree of dispersion of the particles of the electricity storage material to be accurately quantified even if the particles of the electricity storage material are in contact with each other or vary in size.