| | | Introduction Due to the increasing power demand in future vehicles for comfort improvement, as well as ongoing pressures for more environmentally friendly means of transportation, automotive manufacturers are developing alternatives to existing fossil fuel-driven vehicles. Perhaps the most promising near-term alternative to fuel-cell vehicles, which will not be ready for volume production for at least a decade, is hybrid electric vehicle (HEV) technology, while progress has been made in control, engine and motor design, they have not been successful with regard to the electric power storage systems. This is due primarily to the fact that batteries are used to provide the power peaks in most of the currently developed hybrid electric vehicles. But the deficiencies of battery storage systems are multiple and they create many design challenges for automotive engineers. Batteries have a bad low temperature performance, a very limited lifetime under extreme conditions which results in repeated replacement throughout the life of the vehicle, and they are not designed to satisfy the most Important requirements of hybrid electric vehicles power source; to provide bursts of power in the seconds range for events such as acceleration, braking and cold starting. Recently, a very promising technology has been introduced with the potential to improve energy storage in automotive applications: double-layer capacitors. These devices, also known as ultracapacitors or supercapacitors, represent a new generation of electrochemical components with very high capacitance for energy storage. Today, ultracapacitors are a viable component for production-Intent designs. Ultracapacitors are available from major production firms in the United States, Asia, and Europe. They are available In a variety of sizes, In a variety of configurations. Ultracapacitor prices are within the cost targets of many automotive systems, and are approaching $0.01 per farad in automotive production volumes by 2004 In when appropriately designed with a systems approach, they offer excellent performance, wide temperature range, long life, and flexible management. When used in combination with other energy storage solutions (e.g. lead-acid batteries, fuel engines, fuel cells), the complete system can meet performance and cost goals unachievable with a single energy storage device. Ultracapacitors from Maxwell Technologies are available under the trade name of BOOSTCAP®. | | |
