Ultra-capacitors to complement lithium batteries explained

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Ultra-capacitors to complement lithium batteries explained

Postby optical10 » 21 Jul 2018, 11:22

This YouTube video from my favourite EV show "FULLY CHARGED" does an excellent job of highlighting the growing need to complement battery tech to scale out the power draw at peak energy usage time by using ultra-capacitors via a tech start-up.

Can't see it being useful for wheelchair users but does anybody know whether this can be used in a solar, battery and user home environment as opposed to the larger power station mentioned in Scotland?

[YouTube]http://youtu.be/KQ2Eo6wl5r0[/YouTube]

https://www.youtube.com/watch?v=KQ2Eo6wl5r0
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Re: Ultra-capacitors to complement lithium batteries explain

Postby Burgerman » 21 Jul 2018, 15:12

But what he is saying makes no sense.

The only time a capacitor does make sense is if you are selling them or after grant money for more research. They are higher impedance than some lithium cells today. So cannot actually charge faster or discharge faster. But if we ignore that, using really low rate cells, and small sized batteries then they COULD help. But energy density and impedance is WORSE so better to add more lithium in the space wasted by capacitors. But you should not do that too small battery thing anyway, thats the reason people need a BMS to cut power to preotect the cells! Its due to bad design of the full SYSTEM.
Not in solar either because capacity should be large, compared to the charge rate, or your pack is already way too small to serve your property...

Same in a powerchair where we do take massive spikes of current. If we have enough Ah for decent range, a super or any capacitor is redundant and doesent help. Esp as C rate keeps increasing. Already I charge my hobby Lithium packs from 5% to 95% in 8 minutes! (At 8 C) and 12C chgarge is also available now. Thats about 4 mins! Not a capacitor in site!

And if you scale that up to a 90KWH EV pack for eg as used in the teslas, you will then need an impossible 675kw output charger!!!
Plus 10% loss, so 742kW!
And charge cables and wiring in the car the size of your leg...
So even if they allow faster peak charging, you will need your own power station. Peak demand from a house happens intermittently up to about 9kW? But averaged over A LONG PERIOD, and over many properties that around 1100 watts according to the interweb. So you will need the same amount of power than feeds around 700 homes!!!

So how will they help?

Again I can charge my lithium powerchair at 5C max. Its a 3.240kWh pack. So the first 90% of charge COULD be acomplished at CC of 600 Amps!!! As it stands. But we already run out of wall power at the 1 hour rate in the UK, and in the 2 hour in the US... And thats not a car, but a wheelchair. So how will we feed them even faster?
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