Electric and hybrid vehicles have been under development for as long as anyone can
remember, but have so far failed to become widely adopted. There have been some
fundamental problems of energy storage and delivery that have yet to be successfully
and cost-effectively overcome. Many of these issues can be traced to the limitations of
batteries – heavy, large in size, with a limited charging rate and potentially high
maintenance.
System designs can take advantage of the power of ultra capacitors to conserve energy
by allowing the engine to stop while the vehicle is not moving and then to be restarted
nearly instantly on tip in of the throttle. The design also allows regenerative braking
energy to be captured thereby significantly increasing efficiency and reducing pollution.
The use of engine start/stop and regenerative braking has been estimated to produce
between 7 and 15% increased fuel efficiency while reducing pollution by an even greater
percentage.
Announced programs for integrating ultra capacitors into vehicle power trains include big
names such as BMW, VW, Honda, Nissan and Toyota, among st many others. These
vehicles run the gamut from concept to production-intent, and include systems for hybrid
trucks, buses, and passenger vehicles are underway.
remember, but have so far failed to become widely adopted. There have been some
fundamental problems of energy storage and delivery that have yet to be successfully
and cost-effectively overcome. Many of these issues can be traced to the limitations of
batteries – heavy, large in size, with a limited charging rate and potentially high
maintenance.
System designs can take advantage of the power of ultra capacitors to conserve energy
by allowing the engine to stop while the vehicle is not moving and then to be restarted
nearly instantly on tip in of the throttle. The design also allows regenerative braking
energy to be captured thereby significantly increasing efficiency and reducing pollution.
The use of engine start/stop and regenerative braking has been estimated to produce
between 7 and 15% increased fuel efficiency while reducing pollution by an even greater
percentage.
Announced programs for integrating ultra capacitors into vehicle power trains include big
names such as BMW, VW, Honda, Nissan and Toyota, among st many others. These
vehicles run the gamut from concept to production-intent, and include systems for hybrid
trucks, buses, and passenger vehicles are underway.
Problems with hybrid vehicles
Batteries have difficulty functioning in cold weather.
Batteries require a sophisticated charge equalization management.
Batteries have limited cycle life under extreme conditions, which results in high
cost replacement throughout the life of the vehicle. A new battery has to be
purchased and installed; the old battery has to be removed and disposed. Battery
disposal can be problematic unless the manufacturer has a recycling program.
Batteries are limited in their ability to capture and provide bursts of high power
during short duration events such as acceleration and regenerative braking. This
high power limitation reduces the efficiency of the hybrid electric drive system
design.
What is an ultra capacitor?
Ultra capacitors are based on an electric double layer technology that has been
understood for over a hundred years, but only available for commercial applications for
about ten years.
What are the advantages of ultra capacitors as compared to batteries?
They function well in cold weather, down to –40° Celsius, whereas without heating,
batteries do not operate well below 0° degrees Celsius.
They are extremely safe because a pack with equalization is discharged over night.
They have a long life cycle, basically built to last the time of the machine into
which they are incorporated. This means that they are maintenance-free which
ultimately results in costs-savings. This is particularly important for applications
where life-cycle cost is of high value, such as embedded power modules, hybrid
buses and trucks.
They are more efficient than batteries; 84-95% as compared to an average of
below 70% for batteries in this application.
They are very environmentally friendly as they are 70% recyclable and do not
include any heavy metals which are detrimental to the environment.
Ultra capacitors offer up to ten times the power of batteries, which plays an
important role in boosting the acceleration of a vehicle.
Detailed Case Study of Maxwell Technologies.
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