Shovel and method of controlling shovel

A shovel includes a lower-part movable body (1), an upper-part turnable body (3) turnably mounted on the lower-part movable body (1), a boom (4) including a first end rotatably attached onto the upper-part turnable body (3), an arm (5) including a first end rotatably attached to a second end of the boom (4), a work element (6) rotatably attached to a second end of the arm (5), an electrical energy storage device (19) including multiple electrical energy storage cells (19-n), and mounted on the upper-part turnable body (3), a controller (30) configured to control the charge and discharge of the electrical energy storage device (19), and multiple voltage measurement parts (149-n) configured to measure the respective cell voltages of the electrical energy storage cells (19-n). Information on the cell voltages is transmitted to the controller (30).