Construction machine
A storage battery ( 21 ) is configured of a plurality of cells ( 22 A) to ( 22 N) series-connected to each other. A battery controller ( 27 ) receives power supplied from a lead battery ( 31 ). The battery controller ( 27 ) executes balancing control that reduces variation in cell voltages (VcA) to (VcN) of the plurality of cells ( 22 A) to ( 22 N). The battery controller ( 27 ) executes the balancing control in a time range during which a voltage of the lead battery ( 31 ) becomes equal to or more than a predetermined given voltage value (V 1 ) and a charging rate of the storage battery ( 21 ) becomes equal to or more than a predetermined given charging rate value (SOC 1 ) after a key switch ( 16 ) is switched from an on state to an off state.
1. A construction machine comprising:
a hydraulic pump driven by an electric motor;
a working mechanism driven by hydraulic oil delivered from
the hydraulic pump;
a first battery that is configured of a plurality of cells series-connected to each other and supplies power to the electric motor;
a cell voltage detector that detects a cell voltage of each of the plurality of cells;
a battery controller to which power is supplied from a second battery and that executes balancing control for reducing variation in the cell voltage of the plurality of cells; and
a key switch having a drive position for driving the electric motor and a stop position for stopping the electric motor, wherein the battery controller:
calculates a first time as a remaining time required until the balancing control is completed when the key switch is switched from the drive position to the stop position,
calculates a second time as a time during which the balancing control is possible based upon the voltage state of the second battery,
calculates a third time as a time during which the balancing control is possible based upon the charging rate of the first battery,
executes the balancing control by a minimum time out of the first time, the second time, and the third time, and
executes the balancing control in a time range during which a voltage of the second battery becomes equal to or more than a predetermined given voltage value and a charging rate of the first battery becomes equal to or more than a predetermined given charging rate value after the key switch is switched from the drive position to the stop position.
2. The construction machine according to claim 1 , wherein the battery controller:
subtracts an elapse time after the key switch is switched from the drive position to the stop position from the minimum time, and
causes a monitor to display a remaining time of the balancing control.
3. The construction machine according to claim 1 , wherein:
the second battery is connected via a first relay and a second relay parallelly connected to each other to the battery controller,
the first relay is turned to a connection state when the key switch is switched to the drive position, and is turned to a disconnection state when the key switch is switched to the stop position, and
the second relay is turned to a connection state when the battery controller executes the balancing control, and is turned to a disconnection state when the minimum time elapses from a point where the balancing control starts.