Patent ID: 9548615
Date: 2017-01-17
CPC Classifications: B60W,E02F,H01M,H02J,H02K,Y02E

Claim:
1. A shovel comprising: an engine generating a drive power; a generator performing a generating operation using the drive power transmitted from the engine; an electric accumulator having a plurality of electric storage cells in which an electric power generated by the generator is accumulated, the electric accumulator supplying an electric power to an electric load of the shovel; an electrostatic capacity computing unit configured to compute an electrostatic capacity of each of the electric storage cells; an equalizing circuit provided to each of the electric storage cells configured to equalize voltages of the electric storage cells by discharging electricity from the electric storage cells; and a determination unit configured to determine whether to activate the electrostatic capacity computing unit and the equalizing circuit based on a predetermined condition of the electric storage cell, wherein the electrostatic capacity computing unit is configured to separately discharge the electricity from each of the electric storage cells and to compute the electrostatic capacity of each of the electric storage cells based on a voltage of each of the electric storage cells while discharging the electricity, and wherein a temperature difference between a maximum temperature and a minimum temperature of the temperatures of the electric storage cells is computed when temperatures of all of the electric storage cells are higher than a predetermined temperature, and a transition is made to the process of computing electrostatic capacities of the electric storage cells based on the computed temperature difference.