ENERGY STORGE UNIT, METHOD OF MANUFACTURING THE SAME AND METHOD OF USING DETECTION MEANS

PROBLEM TO BE SOLVED: To provide an energy storage unit in which even very small damage to a battery casing can be detected with certainty and with high reliability, and which is simple and advantageous in terms of cost.SOLUTION: There is provided the energy storage unit including a cell space . In the cell space, an anode, a cathode, and an electrolyte arranged between the anode and the cathode are arranged. In the energy storing unit, at least a part of the cell space is separated from an external environment by a casing. The casing includes detection means detecting at least one component or a reaction product of this component existing in the casing at an operation of the energy storage unit.