18 January 2008

Ultracapacitor -- Battery: Hybrid Electric Power

Combining the high energy density of batteries with the high power density of ultracapacitors, provides a better power profile than either alone. From Australia's CSIRO:
The UltraBattery combines a supercapacitor and a lead acid battery that, according to the CSIRO, creates a hybrid car battery that lasts longer, costs less and is more powerful than current technologies.

"Previous tests show the UltraBattery has a life cycle that is at least four times longer and produces 50 per cent more power than conventional battery systems," Mr Lamb said.

"It's also about 70 per cent cheaper than the batteries currently used in HEVs."
Australian Much more on CSIRO at Brian Wang's Blog

Or from the British Motor Show, a Mini-Coop conversion incorporated battery-ultracap hybrid power:
At the recent British Motor Show, PML Flightlink and its partner Synergy Innovations showed a MINI QED — an in-wheel, plug-in, series hybrid conversion of a MINI, which many would agree is a fun car to drive even before these developers achieved an ability to accelerate from 0-60 in 4.5 seconds.....PML Flightlink put 350V worth of 11 Farad ultra capacitors into its Mini QED prototype. The ultra capacitors accept power from regen braking and discharge when high current is required for acceleration.
Source

A Chinese hybrid car effort uses batteries with ultracaps:
For Maxwell Technologies and Tianjin Lishen Battery, hybrid describes a new sort of energy storage product that combines ultracapacitors with lithium-ion batteries. The two companies recently announced they would partner up to produce this hybrid power source, and samples should be available early next year, possibly in EVs....David Schramm, Maxwell's president and chief executive officer, said this hybrid tech "will give end-users the best of both worlds in terms of the long cycle life, rapid charge/discharge characteristics and low temperature performance of ultracapacitors and the large energy storage capacity of lithium-ion batteries."
Source

Secretive Texas startup EESTOR seems to be developing a combination battery/ultracapacitor that is attracting investment from Lockheed Martin, and intense investigation by GMC.
The combining of battery and capacitor attributes is quite exciting. Capacitors are very fast acting allowing very quick charge and discharge abilities that will dramatically improve the usefulness of devices that are self-storage powered. Whether a cell phone, laptop or automobile these attributes will have a strong positive impact in usefulness and consumer adoption.
New Energy

This is the basic idea behind the combination approach:
As a quick energy storage platform, a supercapacitor can charge or discharge in a time of mere microseconds to seconds, whereas batteries take minutes to hours. However, the energy density for batteries is much higher. Hence many believe that the ideal backup energy storage device would be a hybrid of battery and supercapacitor. To be useful in that role, however, supercapacitors must be easily made and integrated onto chips.
Source

Here is an interesting combination of fuel cell, supercapacitor, and battery (my favoured approach):
A fuel cell system that employs a super capacitor and battery electrically coupled in series with each other and in parallel with a fuel cell stack on a power bus line. As the voltage on the power bus line changes over the operating requirements of the system, the super capacitor is charged and discharged over a relatively large voltage swing, such as an 85% SOC swing. The super capacitor equalizes or voltage matches the voltage variation on the power bus line as set by the stack voltage to the voltage of the battery. Therefore, the battery, while providing the majority of the energy and power during charge and discharge, has a relatively small defined SOC swing, which acts to maintain the battery life.
Source

Here is a combo hybrid for delivery vans:
Azure Dynamics is perhaps the best example; they have built delivery vans with electric drives that included super capacitors. With the decreasing size of such energy storage, there even has been a “proof-of-concept” car. But, such an approach, sending “regen” from brakes and suspension into the “power-rich”,ultra capacitor module1, which then gets depleted before any additional charge is drawn from the battery module
Source

These are just a few examples of various attempts to achieve the electrodynamic "sweet spot" that will painlessly replace internal combustion engines with electric drive. We still need some breakthroughs in nano-materials, nano-assembly, and nano power electronics. But it is happening.

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2 Comments:

Blogger StaticNoise said...

This stuff is very exciting. It seems it's only a matter of time before a truly viable alternative to the internal combustion engine will be upon us. I can only see it as a win win situation. Even if it means we burn more coal initially to "charge" our cars. The resulting lower price for oil will make processing natural gas cheaper too.

Sunday, 20 January, 2008  
Blogger al fin said...

Yes, very exciting indeed, Craig. Using coal and natural gas to fuel a fleet of electric vehicles may be the necessary path for a decade or two.

Fortunately there seems to be an abundance of both. And since it's getting easier to turn tar sands and oil shale to methane, and since synthetic biology is getting better at turning grass and crop waste into diesel, butanol, and methane, it does not look like a catastrophic "peak oil" scenario any time soon.

Sunday, 20 January, 2008  

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