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Discussion Starter · #1 ·
You have to scroll down the page I link to a lot to find Nana Technologies

http://cleantechnica.com/2014/11/12...ovation-13-future-energy-system-gamechangers/

They are a French start up claiming to have a super capacitor with the energy density of Lithium batteries.

If they have overcome the other historic disadvantages of supercacitors - self discharge in storage, etc - it could be a game changer for bev. SCEV anyone?!

Elon Musk saw supercapacitors as the future for ev back in 2010. Who knows, maybe he will blindside us all again and quietly produce not batteries but supercapacitors at his giga factory....he studied them himself at uni ;)
 

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I am rather sceptical of these sorts of claims. What you tend to find is that they are claimed that they will (in a few years) be able to compare well to current battery technology. The problem is that there are also companies claiming that in a similar timescale they will have considerably better batteries. So in a few years time you will have long-lasting, very fast charging, cheap batteries, and possibly longer-lasting, even faster charging and similarly cheap but lower capacity supercapacitors. The question then is are the advantages of these supercapacitors enough to outweigh the lower capacity? Is it better to have an EV with a battery that lasts 10 or 15 years rather than with a supercapacitor that lasts 20 or 25 years? What if the battery is 100kWh but after 15 years is down to 65kWh, but the supercapacitor starts at 60kWh as it has a lower energy density? What if you can charge your supercapacitor EV in 3 minutes, but have to stop every 120 miles, but the battery EV takes 10 minutes and will do 200 miles? Also, how on earth are you going to charge a supercapacitor car so fast... charging a 60kW EV in 3 minutes would require a 1.2MW charger!
 

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I believe the LEAF has a small super capacitor for regeneration smoothing.
Can anyone confirm this?
Google gets buried under unrelated references, so I can't find anything definitive.

But I could see a use for small 1-2kWh super capacitor that could be used to reduce the C number for short bursts of acceleration and/or a "turbo" boost option for driving a bigger motor than the battery would otherwise support.
30 seconds of 150kW would make the Leaf pretty awesome.
Can anyone comment on the economics and practicalities of such a thing?
 

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Discussion Starter · #4 ·
Hi Matt Beard appreciate yout scepticism and to some extent share it. But still find it interesting to watch and felt others might...game changing scientific break throughs do happen and one of these may just be one.....! They do if this report is to be believed already have working units which makes it more hopeful than the Canadian supercapacitor company a few years ago which seems to have been vapor ware.

A quick google will find the Chinese bus from a few years ago that recharged in 30 second bursts at each bus stop from overhead cables....this seems a good fit for existing supercapacitor tech and indeed this new company has had the same idea mentioned for them.
 

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Discussion Starter · #5 ·
Metalhead....no supercapacitors in the Leaf. There are some in the blue car used in the Paris car rental scheme...it helps maximise regen efficency when driving round town as it can accept most or all of the rapid charge rate when breaking etc....extends the town driving range from a charge well beyond the Leaf.
 

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As lithium cells are achieving better c rates under charge and discharge, the need for super capacitors is diminished. Its not just a question of adding a super capacitor, but you need fast acting and large current power switching and control gear to handle the power and give it out as needed. If just put across a pack its usefulness is limited, to a verry small time sacle befpore the cells catch up and the capacitor discharges to the cells. Switching 100+kw as commented above would require a serious set of kit to control it.
 

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According to MyNissanLeaf forum in US Leaf has an Ultracapacitor, it is in the charger bay behind and under the back seats. I have seen a photo, will look for it again soon.
 

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Discussion Starter · #8 ·
Apologies then news to me. Is a supercapacitor different from an ultra capacitor? And don't mobile phones have them?

Am already way out of my depth, but my understanding had been that the Bollore / Pinnafirina ev the blue car was unique in it's use of supercapacitors.... explaining an unusually large difference between town and motorway driving range from a charge
 

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If you just connect them across the pack, then they can take a short burst of power in, which a cell may not accept, but would then get taken down by the pack very quickly afterwards. But since they are at pack voltage they wouldnt give you any advantage on acceleration. That needs power control to achieve such usage. In rapid stop start they could use regen current that otherwise couldnt be handled. But its very limited in its advantage. Great sales point though. High tech sells cars.
 

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Thanks for all the info.
So if I'm understanding correctly, the cost of the control electronics plus the cost of the super capacitor makes it's more economical to simply add more battery capacity instead.
I'm still curious what the numbers would be. An sprint version would make an great urban car.
Perhaps put another motor on the rear axle driven by the capacitor bank.
Economic sense, no. Sensible, nope. A lot of fun - quite possibly :)
 

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I think the supercapacitor on the leaf is for the braking system? In the event of total electric failure? I may be wrong though...
 
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