Ultracaps may be the future Battery!

[slickdude]

Okay, I read about this technology. It has over 1 million charge cycles and an immense amount of power in a very small package. I can easily see Ultracaps powering everything depending on charging times of course. Anyhow here is the link for the article on it. I hope they get them for bikes soon Would be nice to have a 35mph 200 mile range bike per charge.

http://www.greentechmedia.com/articles/read/the-future-of-batteries-might-not-be-batteries/

Additional bike uses and tests:

http://jcwinnie.biz/wordpress/?p=2371

Check out this ebike charging ultracaps
http://www.youtube.com/watch?v=1P5tmXbta6U

Check out this page with links on ultracaps.
http://visforvoltage.org/forum/8563-maxwell-boostcap-ultracapacitors

 

[loquin]

I'd heard about them before, but this got me interested in taking a closer look.

Ultra-capacitors aren't really suitable to replace batteries; while they have can store lots of energy and release it quickly, their energy density is less than lithium ion batteries (but greater than SLA batteries.)

They also have issues dealing with their discharge characteristics; the voltage drops steadily over time, unlike batteries, which stay fairly constant until they near their capacity, then start dropping rapidly. Since each ultracap has a low maximum voltage, they must be used in series, which cuts the storage capacity of the capacitor as a whole. For instance, if you want to store 12V in an ultra-capacitor 'pack', using the 3000 farad UTs mentioned in the article, you would need to place 5 in series, which reduces the capacitance of the pack as a whole to 600 farads. Then charge this pack to 12 volts. If you then pull 10 amp out of the pack, in 12 minutes, the voltage has dropped to 4.44V, and in another 12 minutes, it has dropped to 1.6 volts.

Since the output voltage steadily drops as the cap discharges, you need buck-boost regulators to convert the output voltage from the ultracaps into the steady voltage needed for most loads, which limits the efficiency to about 70%.

What is more likely, is that designers will start using ultracaps in conjunction with lithium ion batteries in a hybrid system, using the ultracapacitor packs (ultrapacks) for quick storage and quick release power needs (with lower losses, compared to the chemical reaction losses associated with batteries.)

Regenerative braking, for instance, would be a great use for them; power is stored in the ultrapack as you brake or go downhill, then released from the ultrapack during acceleration. This means that your li-ion batteries aren't being asked to supply the heavy currents during acceleration (most of the time,) but instead, can be sized more towards the 'average' loads.

 

[Cavi Mike]

loquin is spot on. Capacitors also don't like over-voltage. Batteries will dissipate over-voltage as heat and still maintain voltage and stability. A 12v car battery actually holds a pretty steady charge at closer to 13v but the cars electrical system charges even higher, closer to 14v. Batteries can handle this steady over-voltage just fine but a capacitor will just keep charging right past its peak voltage and destroy itself.

Like the article said, capacitors store energy in a much different way and because of this, they have much different uses and will never be a replacement for a battery.

 

[loquin]

Well, the 'pack' the article mentions has incorporated the overvoltage protection internally; as well as the charge circuitry, and possibly the output voltage boost circuitry as well, to make the pack more like a battery in its application. Still, I think its use is going to be limited to specific areas within electric vehicle applications, like handling the surge currents encountered in acceleration and deceleration.

Since they CAN sink and source huge currents with minimal losses, this would be an ideal application for them. And, their relatively high internal leakage wouldn't be an issue in a short-term storage application like this.

 

[slickdude]

Very cool if we could use it for ebikes especially with long range and the fast charge.

 

[wheelbender6]

The regen braking with capacitors reminds me of some of the things they were doing in Formula 1 racing.

 

[slickdude]

A Texas company says it is the first that can have ultracaps that hold a charge like batteries but recharge in a few minutes with a much greater energy capacity. Will be interesting to see if these really do replace gas and current battery technologies as they are making a claim.

 

[Fabian]

Thankfully Formula 1 has been the main driver in developing very compact capacitive charge/discharge batteries with stonkingly fast charge times and energy storage.

The next development curve to be introduced into Formula 1 is thermal energy recovery systems, being charge current created directly from exhaust heat. We should start to see this new technology implemented on base model vehicles within 10 - 12 years as global mass transportation of (enclosed) single occupant vehicles significantly downsizes due to ever escalating fuel costs. The hybrid turbo charged 1 litre engine with thermal energy recovery systems and braking energy recovery systems will become the norm.

 

[wheelbender6]

They are also doing some interesting things in auto endurance racing, like the LeMans series. I think the endurance racers are focusing more on alt fuels, rather than electricity.

 

[Ludwig II]

There will also be some crossover from heavy diesel technology, where a turbo places power back into the system as well as improving the engine's efficiency.