In a case of a normal operation, a battery controller (22) assumes a normal operation mode and permits charging and discharging of a battery module (21). Upon receiving a discharge command from a vehicle body controller (17) for completely discharging the battery module (21), the battery controller (22) assumes a discharge mode to discharge the battery module (21) to reach a safe voltage level and store discharge information. Upon reading out the discharge information, the battery controller (22) assumes a discharge prohibition mode to prohibit charging and discharging of the battery module (21).

A work machine includes: a controller; a first electrical circuit provided with a first power supply that supplies power to the controller; an electric drive source necessary for operating the work machine; and a second electrical circuit provided with a second power supply that supplies power to the electric drive source. The work machine further includes: a capacitor provided to the second electrical circuit; a first precharge device that performs precharge of the capacitor by using power of the first power supply; and a second precharge device that performs precharge of the capacitor by using power of the second power supply. The controller performs precharge by using one of the precharge devices when it is determined that precharge by using the other one of the precharge devices is impossible.

A motor grader in which a motive power source of an electric motor can appropriately be arranged is provided. The motor grader includes a front frame, a rear frame, and a coupling shaft. The rear frame is arranged in the rear of the front frame. The coupling shaft couples the front frame to the rear frame as being pivotable with respect to the rear frame. The motor grader includes a front wheel rotationally driven to run the motor grader, the electric motor that generates driving force for rotationally driving the front wheel, and a battery in which electric power supplied to the electric motor is stored. The battery is arranged in front of the coupling shaft.

A swiveling working machine includes a swivel base; a working device provided on a front side of the swivel base; a battery unit; an electric motor that is driven by electric power output by the battery unit; and a hydraulic pump that delivers a hydraulic fluid by driving of the electric motor. The battery unit is disposed at a rear portion of the swivel base. The electric motor and the hydraulic pump are disposed sideward of the battery unit side by side in a front-rear direction.

An intelligent work vehicle preheating system includes an electric drive subsystem containing a battery pack, a hydraulic subsystem containing a first hydraulic fluid (HF) heating device, and a first HF temperature sensor. A memory stores a first minimum target temperature at or above which a first hydraulic fluid body contained in the hydraulic subsystem is desirably maintained. A controller architecture selectively places the intelligent work vehicle preheating system in an off-duty preheat mode when the electric drive subsystem is connected to an external power supply utilized to charge the battery pack. The controller architecture further controls the HF heating device to heat the first hydraulic fluid body when (i) the intelligent work vehicle preheating system is placed in the off-duty preheat mode, and (ii) the current temperature of the first hydraulic fluid body is less than the first minimum target temperature.

An excavator comprising: an electric motor having a commercial power supply and a battery as the drive power sources therefor; and a hydraulic actuator having a hydraulic pump driven by the electric motor, as the hydraulic source therefor. The excavator has: a first power supply mode in which the electric motor is driven while the battery is being charged by the commercial power supply; and a second power supply mode in which the electric motor is driven only by the battery. A power supply cable for supplying power from the commercial power supply is connected to a power supply port and, if the electric motor has stopped operating, the excavator moves from the second power supply mode to the first power supply mode.

An embodiment of the present invention provides a regeneration system of energy released from a working implement, which includes an actuator configured to move up and down the working implement, an accumulator configured to communicate with the actuator, and a controller configured to receive a pressure value of the actuator and a pressure value of the accumulator to control a discharge operation of the accumulator based on a pressure difference value between the actuator and the accumulator.

A hydraulic excavator includes a starter motor for starting an engine with electric power supplied from a lead-acid battery, a second electric system connected in parallel with a first electric system to connect the lead-acid battery and a 24V electrical equipment, a 48V battery for supplying electric power to the second electric system, a relay for disconnecting connection between the first electric system and the second electric system, and a vehicle body controller connected to the second electric system to control the starter motor and the relay. The vehicle body controller estimates a remaining charge amount of the lead-acid battery and disables driving of the starter motor until an estimation result is higher than or equal to a threshold, and when the estimation result is higher than or equal to the threshold, disconnects the connection between the first electric system and the second electric system by using the relay.

A plus-side main connection line (27) connects electrical equipment (21), (22) to a plus terminal (26A) of a battery (26). A plus-side isolating switch (28) is provided in the plus-side main connection line (27) to connect or disconnect the electrical equipment (21), (22) and or from the plus terminal (26A) of the battery (26). A plus-side auxiliary connection line (30) connects a urea SCR controller (25) to the plus terminal (26A) of the battery (26) in a position upstream of the plus-side isolating switch (28). A minus-side main connection line (32) connects a minus terminal (26B) of the battery (26) to ground. A minus-side isolating switch (33) is provided in the minus-side main connection line (32) to connect or disconnect the minus terminal (26B) of the battery (26) and or from ground.

A hydraulic power distribution system and method for an electric mining machine is described. In one embodiment, the electric mining machine includes a first pump motor configured to drive a first hydraulic pump and a second pump motor configured to drive a second hydraulic pump. The electric mining machine further includes a first battery pack supplying electric power to the first pump motor and a second battery pack supplying electric power to the second pump motor. A hydraulic control system in communication with at least the first battery pack, the first pump motor, the first hydraulic pump, the second battery pack, the second pump motor, and the second hydraulic pump is configured to independently control each of the first hydraulic pump and the second hydraulic pump so that a combined hydraulic power output satisfies 100% of a hydraulic power output demand for the electric mining machine.