1. Technical Field
This invention relates to a battery charging system for charging a vehicle battery pack with an external battery charger.
2. Related Art
A conventional power-supply apparatus for a vehicle, as disclosed in Japanese Patent Application Laid-Open Publication No. 2007-195336, includes an inverter for driving an air-conditioner compressor and charging a vehicle battery pack via a charging socket, and a connection unit for connecting the inverter to either one of the air-conditioner compressor and the charging socket. In the disclosed power-supply apparatus, only either one of the air-conditioner compressor and the charging socket is allowed to be electrically connected to the inverter, which allows the inverter to be shared to thereby reduce a weight of the power-supply apparatus.
However, even when the vehicle battery pack is being charged, an in-vehicle occupant may wish to drive the air-conditioner compressor. In addition, in the case of a refrigerated vehicle or an insulated vehicle, the air-conditioner compressor may have to be driven to keep a shipment at a cooler temperature even during charging the vehicle battery pack. Hence, the disclosed power-supply apparatus suffers from a disadvantage that an electrical load mounted in the vehicle, such as the air-conditioner compressor, cannot be driven during charging the vehicle battery pack.
Since electrical power accumulated in the vehicle battery pack is consumed by the electrical load when the electrical load is driven during charging the vehicle battery pack, the above disclosed power-supply apparatus suffers from another disadvantage that it takes more time to complete the charging. Further, when the electrical load is driven during charging the vehicle battery pack, a behavior of the electrical load may cause an abnormally large current to flow into the vehicle battery pack, which may reduce the battery life significantly.
In consideration of the foregoing, exemplary embodiments of the present invention are directed to providing a battery charging system for a vehicle that allows a vehicle mounted electrical load to be driven even during charging a vehicle battery pack and is capable of charging the vehicle battery pack properly in a short time.