Electric construction machine

Abstract

Provided is an electric construction machine capable of avoiding a situation where charging is difficult to achieve due to the exhaustion of a battery device. An electrically-operated hydraulic excavator includes an electric motor, a hydraulic pump that is driven by the electric motor, hydraulic actuators that are driven by hydraulic fluid discharged from the hydraulic pump, and a battery device that serves as an electrical power source for the electric motor. The battery device includes battery systems that each have a plurality of batteries. A selector switch makes it possible to select either one of the battery systems. An arithmetic control section of an inverter device controls connection change switches through battery controllers to change the connections of the battery systems so that electrical power is supplied to the electric motor from either the battery system or the battery system, whichever is selected by the selector switch.

1 . An electric construction machine comprising:
 an electric motor;   a hydraulic pump that is driven by the electric motor;   a plurality of hydraulic actuators that are driven by hydraulic fluid discharged from the hydraulic pump; and   a battery device that serves as an electrical power source for the electric motor;   wherein the battery device includes a plurality of battery systems that each have a plurality of series-connected batteries and are mutually parallel-connected,   wherein the electric construction machine includes
 connection change control means that can change the connections of the battery systems to select one of the battery systems and let the selected battery system supply electrical power to the electric motor, and 
   display means for indicating a battery system that supplies electrical power to the electric motor.   
     
     
         2 . The electric construction machine according to  claim 1 , further comprising:
 manual selection means that is manually operated to select one of the battery systems;   wherein the connection change control means changes the connections of the battery systems so that the battery system selected by the manual selection means supplies electrical power to the electric motor.   
     
     
         3 . The electric construction machine according to  claim 1 , further comprising:
 a plurality of remaining battery power amount acquisition means that acquires information about the amount of electrical power remaining in each of the battery systems;   motor stop control means that stops the electric motor when a battery system supplying electrical power to the electric motor is exhausted; and   automatic selection means that automatically selects a battery system other than the exhausted battery system when a preselected period of time elapses after the electric motor is stopped by the motor stop control means;   wherein the connection change control means changes the connections of the battery systems so that the battery system selected by the automatic selection means supplies electrical power to the electric motor.   
     
     
         4 . (canceled)