Abstract: A nonaqueous electrolyte energy storage device according to one aspect of the present invention is a nonaqueous electrolyte energy storage device including: a negative electrode including a negative electrode material layer; and a nonaqueous electrolyte containing an unsaturated cyclic carbonate, in which the negative electrode material layer contains a solid graphite particle with an aspect ratio of 1 or more and 5 or less, and the amount of substance of the unsaturated cyclic carbonate with respect to a surface area of the negative active material layer is 0.03 mmol/m2 or more and 0.08 mmol/m2 or less.

Abstract: An energy storage device according to an aspect of the present invention includes: a negative electrode including a negative substrate made of pure aluminum or an aluminum alloy, a conductive layer directly or indirectly layered on the negative substrate and containing a conductive agent, and a negative active material layer containing a negative active material capable of occluding lithium ions at a potential of 0.05 V vs. Li/Li+ or lower; and a positive electrode opposed to the negative electrode and including a positive substrate and a positive active material layer directly or indirectly layered on the positive substrate, and the negative active material layer is layered on the negative substrate and the conductive layer so as to include a region in contact with the negative substrate and a region in contact with the conductive layer.

Abstract: A method for manufacturing an energy storage device according to one aspect of the present invention includes: housing, in a case, an electrode assembly in which a negative electrode and a positive electrode are stacked; housing an electrolyte solution in the case; housing a gas, soluble in the electrolyte solution, in the case after the electrolyte solution is housed in the case; and sealing the case in a state where the gas soluble in the electrolyte solution is housed in the case.

Abstract: An aspect of the present invention is a nonaqueous electrolyte energy storage device including: a positive electrode having a positive composite layer including a positive active material; a negative electrode having a negative composite layer including a negative active material; and a nonaqueous electrolyte including a nonaqueous solvent, in which the positive active material includes a lithium-transition metal composite oxide that contains nickel as a transition metal and has a layered ?-NaFeO2-type crystal structure, a ratio (N/P) between mass (N) per unit area of the negative active material and mass (P) per unit area of the positive active material is 0.30 or more and 0.