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Hybrid Electric Vehicle Energy Storage System

Novelty: This invention provides both a combined battery/ultracapacitor energy storage system and battery chargers associated with these systems. First it combines an ultracapacitor with a battery to optimally power both high current surges and more constant demands. The ultracapacitor provides the high current power thereby insulating the battery from such uses. Second the technology introduces a circuit with a switch and control device to monitor the current load on the system and regulate the battery charging cycle accordingly. This allows the ultracapacitor to protect the battery even during a charging cycle while keeping a nearly full charge on the battery at all times. As a result battery life is improved and inexpensive lead acid batteries may be used in this demanding application. Invention Description: Hybrid Electric Vehicles will benefit from this energy storage system consisting of an ultracapacitor combined with a battery. The ultracapacitor delivers energy during periods of high current surge such as engine start acceleration and regeneration. This allows the battery to be used only for long duration loads optimizing its energy storage and increasing its life. A battery charging control circuit assists such systems by allowing the ultracapacitor to work during periods of battery charging and continuously keeping the battery at near 100% charge. Applications: Hybrid Electric Vehicles which require the extended storage capacity of a battery but demand brief high current surges from their power system.


1. Battery life is increased because circuit allows a battery to be optimized for energy storage rather than having to respond to high current surges. 2. The energy storage optimization allows inexpensive lead acid batteries to be used in systems that experience these surges rather than costly nickel-metal-hydride or lithium-ion batteries. 3. Battery life is further increased because this circuit keeps the battery in a state of nearly full charge at all times. 4. The use of an ultracapacitor provides fast high current response to demands for engine start acceleration and regeneration power.

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