Exide Technologies has signed a multi-year development and supply agreement with Maxwell Technologies to develop and market stored energy systems for military, commercial and certain types of passenger vehicles.
The partnership will produce battery/ultracapacitor systems that incorporate Exide Technologies’ spiral-wound Exide Select Orbital batteries and Maxwell’s PowerCache Ultracapacitors.
Applications will include cold-starting and 42-volt systems for hybrid internal-combustion/electric vehicles, commercial medium- and heavy-duty trucks, and military ground, surface and sub-surface vehicles.
Earlier in May, Solectria Corporation announced that it too had signed a strategic development and supply agreement with Maxwell Technologies to collaboratively develop advanced hybrid electric drive systems incorporating Maxwell’s PowerCache ultracapacitors.
James Worden, Solectria’s Chief Executive Officer, said that Solectria planned to develop standard power packs, consisting of 100 to 300 PowerCache ultracapacitors. Worden said that a key initial target application for Solectria’s ultracapacitor-based hybrid electric drive systems is the 100,000 vehicle-per-year medium-sized bus and truck powertrain market.
Research conducted by the Northeast Advanced Vehicle Consortium (NAVC) and the Vermont Electric Vehicle Program (EVermont) demonstrated that a Solectria electric car equipped with PowerCache ultracapacitors had 32 percent greater range and improved performance as compared to a vehicle relying entirely on battery power.
Ultracapacitors enhance performance and extend the life of on-board battery systems by recapturing energy from braking and releasing the energy in high power bursts for acceleration over hundreds of thousands of discharge/recharge cycles.
Funding for Solectria’s ultracapacitor research program for electric vehicles was provided in part by the Defense Advanced Research Projects Agency (DARPA) through the NAVC and EVermont as well as by Solectria and Maxwell Technologies.
An ultracapacitor, or ‘super-capacitor’, stores energy electrostatically by polarising an electrolytic solution. Though it is an electrochemical device (also known as an electrochemical double-layer capacitor) there are no chemical reactions involved in its energy storage mechanism. This mechanism is highly reversible, allowing the ultracapacitor to be charged and discharged hundreds of thousands of times.
An ultracapacitor can be viewed as two non-reactive porous plates suspended within an electrolyte, with a voltage applied across the plates. The applied potential on the positive plate attracts the negative ions in the electrolyte, while the potential on the negative plate attracts the positive ions. This effectively creates two layers of capacitive storage, one where the charges are separated at the positive plate, and another at the negative plate.