ENERGY STORAGE DEVICE

An energy storage device includes an electrode assembly having a negative electrode plate and a separator wound around a tubular core material. The core material has a first line part and a second line part extending along a first imaginary line and a second imaginary line parallel to a long side surface of a case, respectively. At least one of the first line part and the second line part has a curved portion that protrudes toward the other beyond the first imaginary line or the second imaginary line. An inner peripheral edge of the negative electrode plate is located at a position other than the curved portion in at least one of the first line part and the second line part.