ELECTRICITY STORAGE DEVICE

Provided is a technique for suppressing an inside short circuit of an energy storage device from being caused. An energy storage device disclosed herein includes an electrode assembly including a positive electrode, a negative electrode, and a separator, includes a case configured to accommodate the electrode assembly, and includes a spacer arranged between the case and the electrode assembly. The separator configures an outer surface of the electrode assembly. The separator configuring the outer surface of the electrode assembly is configured to cover a part of the spacer and is joined to the spacer.