Lithium Sulphide

[Deleted member 4366]

I forgot about this: I got the latest on Lithium sulphide at the show. It seems that it's now iminent. It going to be initially 1C discharge, the same size as LiFePO4, but half the weight. I think he said that they're working on the charge cycles and will get it up to about 1000 at the start. No mention of cost, but logic says it'll be at least as expensive as LiFePO4, but maybe it'll start pushing prices down

 

[Kudoscycles]

I forgot about this: I got the latest on Lithium sulphide at the show. It seems that it's now iminent. It going to be initially 1C discharge, the same size as LiFePO4, but half the weight. I think he said that they're working on the charge cycles and will get it up to about 1000 at the start. No mention of cost, but logic says it'll be at least as expensive as LiFePO4, but maybe it'll start pushing prices down

Dave-that energy density is 6 times the LifePo4 and 4 times LiMno4,so its tempting. But no importer will have the nerve to sell batteries with such low cycle life,especially if the cost is high. Imagine the responsibility of building bikes with batteries that may have only 50 recharges.
When approached by the guy who is pushing this chemistry I asked for minimum 1000 cycles and cost less than £150,Usain Bolt would have been impressed by the speed he left my stand.
Dave
Kudoscycles

 

[Deleted member 4366]

Dave-that energy density is 6 times the LifePo4 and 4 times LiMno4,so its tempting.

Kudoscycles

Those are probably achievable in the lab. The figures I gave are what the guys said will actually be in the batteries when they go on sale shortly. So, they'll be the same size and performance as LiFePO4 batteries, but half the weight. Then you consider that the case weight won't change, so your average 10aH battery will only be about 1kg lighter. Therefore the change won't be significant initially.

 

[amigafan2003]

Are they as safe at Lifepo4 cells? The size of batteries doesn't bother me but the weight does. I'd be willing to get one and strip it out of the case and encase it in some cf sheeting and pop it in a pannier bag.

As soon as a battery beats my lipo packs for weith I'm on it!

 

[cwah]

Half the Lifepo4 weight... isn't what we already have with the NMC battery from BMSBattery at 192wh/kg? (without case and BMS)

They are also described as having 800 cycles, so similar to these lithium sulphide?


Amigafan2003, plenty of battery beat lipo in term of weight (NMC, Dow Kokam, Allcells..) but they usually either have a very low C rate, or very low cycle life or are very expensive. Sometime they even have all these issues together lol (Allcells)

 

[flecc]

I'm still concerned about the low number of recharges with these during the development stages and find the sudden leap to a claimed circa 1000 charges suspicious. Could be like the original NiMh when they really were metal hydride, 1000 charges promised but 100 achieved if one was lucky and never rising usefully above 400 after complete re-specification.

 

[eddieo]

aren't Visper working on this as well......Come on David we miss you!

 

[flecc]

David did say so, but I don't think it was finally committed to, though he was enthusiastic about the prospect. The change to German e-bike production is probably giving him more than enough to deal with, without a change in battery technology as well.

 

[shemozzle999]

Latest article I could find on this technology, still seems a long way off after reading this:

X-ray imaging lets Stanford-SLAC team observe running batteries

 

[Deleted member 4366]

On Trade Day, the guys from OXISenergy were actively touting their batteries to prospective customers (e-bike importers and manufacturers). I was helping Andrew on the Oxygen stand. That's why I was able to talk with them directly. They gave the impression that their release onto the market was imminent.

 

[Woosh]

According to my other-half, the battery used in the experiment at the SLAC is too primitive.
Lithium Sulfur designs need to overcome the relatively high surface tension of Lithium polysulfides which form a voltage barrier around the carbon sulfur electrode, stopping free Lithium ions in the electrolyte from approaching the carbon/sulfur surface, a phenomenon called passivation. There are two ways to reduce surface tensions: either using carbon nanotubes or machining sub micron carbon pits. He thinks we are many years from making working LiS batteries, mainly because you'd have to figure out how to slice open the millions of nanotubes required for each battery.

 

[NRG]

I wouldn't want to be an early adopter of this technology, it could be a very expensive mistake.

 

[Tim]

I thought I could smell brimstone at the show. Or bull****. Maybe both.

 

[Deleted member 4366]

I can't understand why you lot are so sceptical. It's not a couple of guys in a shed. They've invested millions and are presently recruiting production personnel. I copy this from one of their vacancies,

"Tooling Design Engineer

We are moving from R&D to pre-production and require a tooling design engineer who can take a project from conception to execution, who has the ability to solve problems and design solutions, produce BOMs, source materials and work to budget and time constraints . It is envisaged that the engineer will have extensive tool making experience both in the design and manufacture of jigs, fixtures and special purpose tooling. ......."

 

[Woosh]

There are good, light weight non-rechargeable LiS batteries on sale but not the kind of batteries suitable for automotive applications.

 

[Deleted member 4366]

Hatti, if by that you mean that they might be developing/producing batteries for other applications, why would they be wasting their time touting for e-bike battery business at the bike show?

 

[Scimitar]

He thinks we are many years from making working LiS batteries, mainly because you'd have to figure out how to slice open the millions of nanotubes required for each battery.

Come up and see my laser etchings.

 

[flecc]

I can't understand why you lot are so sceptical.

Where I'm concerned it's just caution from previous experiences Dave. Generation after generation of rechargeable battery technologies have failed to deliver what was claimed at the outset, sometimes by huge margins like the NiMh example I gave above.

So I adopt the somewhat cynical cautious approach until a new one is proven.

 

[Kudoscycles]

Nobody has put a cost on this product. So many of these research led products just don't consider the costings,I get beseiged at the NEC by formula one type suppliers who tell me their latest wonder product is going to take the marketplace but when I press them for a quote on 500 units they quote a price which is still 10 times what I am currently paying.
Does anyone have a volume cost price for this product?
Dave
Kudos Cycles

 

[Deleted member 4366]

Where I'm concerned it's just caution from previous experiences Dave. Generation after generation of rechargeable battery technologies have failed to deliver what was claimed at the outset, sometimes by huge margins like the NiMh example I gave above.

So I adopt the somewhat cynical cautious approach until a new one is proven.

I'm sceptical too, but it seems that soon they'll be producing something. I don't believe for a minute that it'll revolutionise ebikes, but hopefully it'll be another viable alternative in the long term. I wish them well and hope they succeed. At least they're British (based).