ELECTRIC ENERGY STORAGE DEVICE WITH CELL ENERGY CONTROL, AND METHOD OF CONTROLLING CELL ENERGY

A device which transfers energy charged in an arbitrary cell among cells C1 to C6 from said cell to the input/output terminals 33, 35 of a unit energy storage device, comprises a transformer T1 having a plurality of coils comprising primary and secondary coils L1 to L6, and L7, mutually coupled magnetically but electrically insulated; switching circuits SW1 to SW6 which open and close the circuits of the above primary coils of the above-transformer T1 connected to the arbitrary cell; a circuit connecting the second coil L7 of the above transformer T1 via a rectifying circuit D1 to the input/output terminals of the above unit energy storage device; and a control circuit 23 which, by operating the above switching circuits SW1 to SW6, adjusts the amount of energy stored in the above cells to a specific ratio with respect to the amount of energy stored by the unit energy storage device.