Lithium Sulfur - the next big thing?

[axolotl]

Not commercially available yet but they are a proven concept in electric flight:

http://en.wikipedia.org/wiki/Lithium–sulfur_battery

Benefits:

2-3 times the energy density of lithium ion and up to 1500 cycles.

 

[flecc]

There being no signs of availability after more then six years probably speaks volumes. If they were so good and reliable, they would surely have appeared in electric cars by now, since that is where the real money and volume potential is.
.

 

[trex]

there are just too many problems to solve before Lithium sulfur can take off. The biggest problem is relatively low discharge rate, between 0.1C to 0.5C making them unsuitable for e-bikes, we need 2C discharge rate. Taking into account the 10% density gain in processing for current e-bike batteries at least in the next 5 to 10 years, e-bike batteries are getting lighter and cheaper.
I can't see Li-S replacing current e-bike batteries.

 

[Deleted member 4366]

We went through all this with lithium sulfur about two years ago. It was imminent then, but I don't think we're any closer yet.

 

[Kudoscycles]

I don't believe that 1500 cycles,when Lithium Suphur was first shouted about,it was only 50 cycles....David Miall from Wisper had a big involvement with Lithium Sulphur but then went quiet. If you want long life then LifePo4 is the answer,maybe 10 years life but heavy,I was with a lady today who had one of our original Kudos King bikes,done over 3000 miles in 4 years and the battery still going strong,in fact I don't think we have ever supplied a replacement battery for any of those original Kudos LifePo4 (Lithium Iron Phosphate) batteries....I would like to manufacture the Kudos King again but everyone demands lighter bikes.
If you want lighter then LiMnO4 or Lithium Ion or Lithium Polymer is the norm,it should last 3-4 years.
I keep my eye on new battery technology but nothing new seems to replace those 2 alternatives.
KudosDave

 

[axolotl]

Interesting stuff. Sounds like it's not ready for the market yet - of course that doesn't mean it never will be. I guess there are one or two engineering problems to solve first.

 

[JohnCade]

Interesting stuff. Sounds like it's not ready for the market yet - of course that doesn't mean it never will be. I guess there are one or two engineering problems to solve first.

A bit like perpetual motion....

 

[axolotl]

Not really.

 

[flecc]

Interesting stuff. Sounds like it's not ready for the market yet - of course that doesn't mean it never will be. I guess there are one or two engineering problems to solve first.

Few new battery technologies announced ever make it to the market. In most cases the claimed advantage turns out to be trade-off against other desirable characteristics. Those that we use are an optimum balance between all the main factors of capacity, charge rate, discharge rate, weight, bulk and cost.

Improve any one and another one or more suffers. It's chemistry of course, not electronics, so doesn't enjoy the meteoric progress of the latter.
.

 

[axolotl]

Few new battery technologies announced ever make it to the market..

True. That has more to do with poor science journalism though: many newspapers and journals simply parrot the press releases of pre-IPO companies without bothering to fact-check.

But the fact is, there has been enormous progress in battery technology in the last few decades. When I was a kid, NiCd was the best rechargeable technology out there. Half of the portable gadgets we have now would be unthinkable with that kind of battery.

 

[flecc]

But the fact is, there has been enormous progress in battery technology in the last few decades. When I was a kid, NiCd was the best rechargeable technology out there. Half of the portable gadgets we have now would be unthinkable with that kind of battery.

Indeed, but for some while now we do seem to have hit a brick wall in many respects. The gains over the last decade have been mostly in service life which has been greatly improved as the chemistries have been refined. The best examples have two to three times the life of those of seven years or so ago.

But bulk in particular and to some extent weight are proving difficult to improve upon, and charge rates continue to dictate service life. With the large potential and wealth of car production I had hoped their arrival on the electric road vehicle scene would have achieved more, and the fact that it hasn't seems to indicate being increasingly up against physical laws. Chemistry has absolute limits, and we may be close to them now.

The answer may be in another technology like fuel cells, super-capacitors or a presently unknown approach.
.

 

[Wisper Bikes]

Lithium Sulphur is still on the back burner, we are still involved though and there are two Sulphur Wisper Alpinos currently running around the roads of Abingdon.

We are now using Samsung cells in all our new bikes, Li Po seems to have slipped back a bit. The new Wispers to be unveiled at the NEC later this month sport 400Wh and 560Wh rack batteries with balanced chargers, both can be interrogated using a BUS connection to a PC. The batteries are being built by the Apple battery manufacturers, amazing quality, real state if the art.

All said we still have Wispers running on 8 year old LiPo batteries!

One of the best improvements recently has been in BMSs, our new Wisper Torque and Kombi batteries will not start their two year warranty until the battery has been charged for the first time, as long as that is within 2 years of manufacture. There will also no longer any need to condition our batteries over the winter, they go into deep hibernation and will last for up to 12 months with out the Voltage dropping to critical.

All good stuff.

I cant see a move to Li Sulphur anytime soon.

All the best

David

 

[Deleted member 4366]

Chemistry has absolute limits, and we may be close to them now.

A sharp intake of breath was heard.

Theres 25,000,000 kw-hours of energy in 1 gram of battery, so I think there's a bit of a way to go before we reach that limit. We just need to find a way of converting it - slowly. The potential for energy storage and conversion using chemistry is beyond comprehension. Sooner or later somebody will make a discovery that will have a significant result. In the meantime, battery development is continuous. Capacity and discharge rates are still going up and weight going down.

 

[axolotl]

Chemistry has absolute limits, and we may be close to them now.

I'm assured by my next-door neighbour (who happens to be a research chemist) that we're a long way off the limits of chemistry. Apparently the main concern with using more lively chemistry in batteries is safety. In the lab they can make batteries based on far more reactive components (e.g. sodium-sulphur) but making them safe and reliable is a huge engineering challenge.

In fact, I'll ask my neighbour if he can drop by and post his thoughts on this topic. He's vastly more knowledgeable about this than I am, obviously.

 

[flecc]

A sharp intake of breath was heard.

Theres 25,000,000 kw-hours of energy in 1 gram of battery, so I think there's a bit of a way to go before we reach that limit. We just need to find a way of converting it - slowly. The potential for energy storage and conversion using chemistry is beyond comprehension. Sooner or later somebody will make a discovery that will have a significant result. In the meantime, battery development is continuous. Capacity and discharge rates are still going up and weight going down.

I won't hold my breath waiting for atomic scale energy realisation!

As I posted though, the rate of improvements are slowing and are snails pace in some respects. As you said, converting - slowly.
.

 

[Wisper Bikes]

Lithium Plutonium 239 should go like a bomb?

 

[trex]

I'm assured by my next-door neighbour (who happens to be a research chemist) that we're a long way off the limits of chemistry. Apparently the main concern with using more lively chemistry in batteries is safety. In the lab they can make batteries based on far more reactive components (e.g. sodium-sulphur) but making them safe and reliable is a huge engineering challenge.

In fact, I'll ask my neighbour if he can drop by and post his thoughts on this topic. He's vastly more knowledgeable about this than I am, obviously.

there was a lot of hope back in the 60s and 70s when I was at uni that bio-membrane chemistry would solve the battery problem. Progress stopped for a while then I saw a post last week about sucrose cells. I still think bio cells are the way to go.

 

[Kudoscycles]

Lithium Plutonium 239
I think the Russians may have increasing applications over the coming months.

 

[axolotl]

there was a lot of hope back in the 60s and 70s when I was at uni that bio-membrane chemistry would solve the battery problem. Progress stopped for a while then I saw a post last week about sucrose cells. I still think bio cells are the way to go.

Well, maybe. The energy density of food is awesome but the only efficient way to utilise it is to eat it an pedal away!

There's also the somewhat pernicious issue of fuel for transport competing with our food supply...