1. Field of the Invention
In general, the present invention relates to charging port systems and methods that are used to charge batteries within various vehicles, such as electric cars and traditional gasoline powered vehicles. More particularly, the present invention relates to the structure of the electrical interconnection made between the vehicle and an external power source when the vehicle is in its charging bay.
2. Prior Art Description
Most all modern automobiles have batteries. In traditional gas-powered automobiles, batteries are used to start the engine and otherwise operate the electrical components of the automobile. In electric automobiles, electrical storage batteries are used to run electric motors that directly propel the automobile.
Due to the weight and relatively low storage capacity of traditional batteries, electrically powered vehicles tended to be limited to small vehicles, such as golf carts and children's toy carts. However, as batteries have improved in storage capacity and decreased in weight, several electrically powered passenger automobiles have become commercially available.
All traditional and electric vehicles that contain batteries need to have their batteries periodically recharged. Vehicles that have all electric drives typically have no way to charge their own batteries. Consequently, electric vehicle must also be connected to a charger when not in use. Traditional gas-powered automobiles recharge their batteries using an alternator that is powered by the gasoline engine. Likewise, hybrid automobiles recharge their batteries using a gasoline engine while the automobile is driving. Even if a traditional or hybrid vehicle is not running, there exists a small drain on the battery that is caused by the certain electrical components of the vehicle. If a traditional vehicle or hybrid vehicle has a weakened battery and is not driven within a period as short as a few days, then the battery may drain too low to start the vehicle. Consequently, if a traditional or hybrid vehicle is to be parked for a long period of time, it is often attached to a trickle charger that provides a small but constant charge to the vehicle's battery.
When an electric vehicle or a traditional gas-powered vehicle needs it batteries recharged, the batteries within the vehicle are connected to an external power source. This required the owner of the vehicle to find an external charger cable and manually connect the charger cable to the vehicle. This recharging process has many drawbacks. For instance, many people park their cars in small garages that do not have a lot of room. It is difficult to maneuver around a vehicle in such a setting and attach an electrical cable to the vehicle. Consequently, many vehicles do not have their batteries recharged as often as they should be. Furthermore, if an automobile is plugged into an external charger, a driver may forget about this interconnection when they enter the vehicle and begin to drive. This can cause damage to both the vehicle and the charging system as the retreating vehicle breaks the cable and/or cable connections.
To eliminate the stated problems of recharging a vehicle's battery, many recharging systems have been developed that rely upon induction charging. Induction charging systems place an induction coil in the vehicle and an induction coil at a charging port. As long as the electric vehicle is parked properly at the charging port, the induction coil in the charging port will create a charge in the induction coil in the electric vehicle. There is no mechanical interconnection between the vehicle and the charging port. In this manner, no charging cable has to be connected or disconnected. Induction coil charging systems for vehicles are exemplified by U.S. Pat. No. 5,498,948 to Bruni, entitled Self-Aligning Inductive Charger, and U.S. Pat. No. 5,703,461 to Minoshima, entitled Inductive Coupler For Electric Vehicle Charger.
Although recharging systems that use induction coils eliminate the need for a connector cable, such systems do have their own problems. The largest problem associated with the use of induction coils is the problem of charging efficiency. When using an induction coil, only a percentage of the current generated in the charging coil is induced in the receiving coil. The efficiency of the power transfer depends greatly upon the alignment of the induction coils and the distance between the induction coils. Consequently, far more energy is used to charge batteries using induction coils than is needed to charge those same batteries with a direct cable connection. Since the owners of electric vehicles tend to be conscious of power usage and power waste, charging using induction coils is not an attractive alternative to direct cable charging.
A need therefore exists for a system to charge a vehicle's battery that eliminates the need for a plug-in charging cable, yet does not use induction coils that waste energy. This need is met by the present invention as described and claimed below.