Energy storage device, method for manufacturing energy storage device, and energy storage apparatus

Abstract

An aspect of the present invention is an energy storage device including: an electrode assembly obtained by winding a band-shaped positive electrode including a positive active material layer, a band-shaped negative electrode including a negative active material layer, and a band-shaped separator in the longitudinal direction; an electrolyte solution; and a case that houses the electrode assembly and the electrolyte solution, where at least one of the positive active material layer and the negative active material layer contains a hollow active material particle, the winding axis of the electrode assembly is located parallel to the horizontal direction, at least a central part of the electrode assembly is pressed with the case pressed, an excess electrolyte solution that is a part of the electrolyte solution is present between the electrode assembly and the case, the lower end of the electrode assembly has contact with the excess electrolyte solution, and the relationship between the height H from the liquid level of the excess electrolyte solution to the upper end of the electrode assembly and the width Wc of the positive active material layer satisfies the following formula 1:0.8≤2.0  1