BATTERY CONTROL APPARATUS AND HYBRID FORKLIFT HAVING THE SAME

摘要

A battery control device and a hybrid forklift truck provided with an engine and battery-driven motor generator and equipped with the device with which control is performed so that excessive exhaustion or charging of the battery does not occur in operation of the forklift truck. SOC of the battery is determined from an established relationship between battery voltage and SOC when battery current is zero for at least a predetermined time period and SOC is also determined from an established relationship between battery voltage, current and SOC when discharge current is constant for at least a predetermined time period. SOC of the battery is revised on every chance battery current is zero or constant for at least the predetermined time period, and SOC at any point of time in operation of the forklift truck is estimated by integrating battery current from the time point of SOC revision and subtracting the integrated current from said revised SOP. Allocation of drive power of the engine and motor generator is performed in accordance with an established relationship between permissible discharge and charge current and SOC of the battery so that excessive exhaustion or excessive charging of the battery does not occur.