Another battery technology forecast

Artstu

Esteemed Pedelecer
Aug 2, 2009
2,225
142
#1
Oct 25, 2006
41,347
2,120
#4
It's at least four year since graphene use was first proposed, and we are still waiting. I think the claims are unrealistic, since it's only the anode using graphene instead of carbon, and graphene is carbon anyway. The theory is that graphene nanotubes in the anode make it more efficient, but I don't see that claimed order of gain.
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Woosh

Trade Member
May 19, 2012
9,764
1,795
Southend on Sea
wooshbikes.co.uk
#5
Replacing graphite lamellar compound in the anode with carbon nano tubes and graphene makes sense but if you increase the capacity of the anode, you also need to increase the capacity of the oxide cathode. Progress on the cathode is slow.
When Lithium ion moves from one electrode to the other. The receiving electrode swells, the depleting electrode shrinks. They physically break down over time and the more their volume changes per cycle, the quicker they die. there is a physical limit for practical cells. Claiming 2.5 times more energy is not really possible. For e-bikes, I reckon 50% increase in energy density may be possible with graphene.
 

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,512
784
The European Union
#6
I don't know if HobbyKing Graphene LiPo is real graphene or not but the batteries do hold more energy and do charge faster than Multistar.
 

danielrlee

Esteemed Pedelecer
May 27, 2012
1,107
91
Westbury, Wiltshire
torquetech.co.uk
#7
I don't know if HobbyKing Graphene LiPo is real graphene or not but the batteries do hold more energy and do charge faster than Multistar.
OOI, how fast do you charge your HK Graphene packs? I charge my Multistars at ~1.5C (42Ah @ 63A) without any significant warming, but am looking at replacing them after 3 years of service with a smaller, lighter pack due to lower range requirements nowadays. I'd like to maintain the 63A charge current and am wondering how high I can realistically go.
 

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,512
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The European Union
#8
I charge all packs at 1C - 10000 mAh packs so 10 Amps. The Multistars don't get warm of course at 1C but they take about 7-10 minutes more to charge than the Graphene (depending on state of discharge). The Multistars are good for about 8 Ah discharge whereas I have had 9.3 Ah from the Graphenes, taking both down to 3.65 LVC per cell.

Inconvenients? They are bigger and heavier. And much more expensive unless you buy only at cut price special offer.
 

danielrlee

Esteemed Pedelecer
May 27, 2012
1,107
91
Westbury, Wiltshire
torquetech.co.uk
#9
I charge all packs at 1C - 10000 mAh packs so 10 Amps. The Multistars don't get warm of course at 1C but they take about 7-10 minutes more to charge than the Graphene (depending on state of discharge). The Multistars are good for about 8 Ah discharge whereas I have had 9.3 Ah from the Graphenes, taking both down to 3.65 LVC per cell.

Inconvenients? They are bigger and heavier. And much more expensive unless you buy only at cut price special offer.
Ta for the info. For my usage there doesn't seem a compelling reason to opt for Graphene over Multistars. If they were available as higher capacity packs, it'd probably sway me enough, but I'm currently a bit "meh". I've gotta say that the Nano-Tech packs are looking more attractive every time I revisit the matter.
 

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