Lithum Sulphur battery announcement

[flecc]

Once again an announcement about a hoped for lithium-sulphur battery breakthough. This type holds huge promise for low weight with very high capacity, but with those characteristics have very short life to date. At one time Wisper were hoping to introduce them on their e-bikes.

This latest announcement concerns research into achieving long life with the desirable characteristics:

Link to Li-S story
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[KirstinS]

I used to get very excited by the new battery tech breakthrough annoucements but now I am very jaded and cynical - all seems to be vapourware. Even the Ryden cell by PowerPlus JApan. That one I thought would happen as it said it could use exiting factory setups - they were going to do a run of 18650 cells last year...........nothing ever happened. May I ask if you asribe better chances to this tech ? If so id be interested to know why it wont be another vapourware annoucement

 

[flecc]

No, I remain as cynical as you about battery announcements. The one thing that makes this a little more of a possibility than the theoretically based announcements is that these batteries have been successfully built with the low weight and very high capacity.

So only the life is a problem to be solved, to date insufficient charge cycles to justify marketing. And we should always remember the story of "The Boy Who Cried Wolf". One day there may finally be a breakthrough to catch us out.
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[KirstinS]

ok cheers flecc - I'll dial my BS detector meter back down to amber then

 

[Kudoscycles]

When the Lithium Sulphur batteries were first announced by this company Wisper got very excited about it,the technology was used in space stations and distress beacons but the big problem was number of recharges,about 50 if I remember.
There never seems any actual reviews on real bikes,it all seems in-house theory and presentation.
KudosDave

 

[trex]

our current mass produced 3300/3400mAH 18650 50g cells have a practical gravimetric energy density of 240WH/kg. Oxis claim that they will achieve 300Wh/kg in 2016. By then, Lithium ion would have made another 8%-10% increase in density. LiS may have arrived by then but hardly competitive.

 

[flecc]

But after the intense development effort to date, lithium ion is getting near to it's limit, while that company did say their aim for Li-S is 400Wh/kg, the 300 for 2016 being only an interim.

If they were to achieve that 400 with better longevity, lithium ion could become uncompetitive, since it's unlikely that their current 240Wh/kg would reach 400.

I remain cynical and doubt they will be successful with Li-S, but as said, one day we may just get an unexpected pleasant surprise in a battery development.
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[flecc]

When the Lithium Sulphur batteries were first announced by this company Wisper got very excited about it,the technology was used in space stations and distress beacons but the big problem was number of recharges,about 50 if I remember.
There never seems any actual reviews on real bikes,it all seems in-house theory and presentation.
KudosDave

Yes, it was 50 charges. I doubt it could get to a review stage due to that charge maximum then, there would be no point since it couldn't be marketed.
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[trex]

We get 2C continuous discharge with Lithium ion cells, about 7A at the moment with 3400mAH cells. Assuming that Oxis get to 400WH/kg in 2017, will their '18650' cell be able to deliver 12A?
http://en.wikipedia.org/wiki/Lithium–sulfur_battery
Without that 2C capability, one can only increase the capacity but not decrease the weight of e-bike battery. Oxis don't seem to disclose their discharge rate, the old pdf disclosed 0.2C which is 10 times less than what is needed for e-bikes. This paper shows the potential of Oxis lithiated graphene being the right approach for e-bikes: http://www.ncbi.nlm.nih.gov/pubmed/24219588

 

[flecc]

Yes, that certainly looks promising if achievable Trex.
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[trex]

I was reading up recently about LENR, it sounds promising.
Just hope they make some progress within a generation.
http://www.innovationtoronto.com/2014/10/for-those-wanting-an-update-on-cold-fusion/

 

[flecc]

Rossi's claims I still find impossible to accept, each new mention of them being couched in such vague terms. If he really has made a new discovery, why in so long a time aren't there sufficient patent protections enabling more explicit information on how it's done?

As it stands, it's more magic circle than science.
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[SteveRuss]

Wow you guys are clever..

 

[Hobbehod]

There is another stream of battery development that may be showing more promise:

http://m.bbc.co.uk/news/technology-30708945

Imagine a network of reasonably priced charging points, perhaps at petrol stations, where you can recharge in a couple of minutes. This would diminish the need for more energy-dense batteries and allow people to ride electric bikes without a limit to range. Realistic within the next few years or nonsense?

 

[trex]

It's a good idea, but needs to allow a bit more time, 5 minutes may be.
You need to push into the battery about 500WH at the charging station to be realistic. If you have to do so in 2 minutes, the battery has to accept 30KW input power in those 2 minutes. Quite dangerous.

 

[Hobbehod]

I think I could cope with 5 minutes.

I'm not a techie and not arguing for them but they are are talking of a car that charges in 3 minutes. Is it possible that their battery technology solves the 'quite dangerous' power input problem or is this all too good to be true?

 

[trex]

the only way to charge a hybrid car in 3 minutes is to put unleaded petrol in the tank. If you want to charge your 15AH battery in 2 minutes, you need an charging current of 450A. You'll need this kind of copper wire inside and outside the battery:

 

[flecc]

There's no future in this sort of high speed charging for cars, each outlet would need a substation fed from the national grid overhead lines to recharge up to 8 or more cars at a time. (Circa 4000 Amps)

That's impossible to create within an existing national structure.
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[jonathan75]

T..two g..gigawatts??!

 

[flecc]

If the charging is to be that fast.

The only viable way to have lightning fast recharge of cars is like the Israeli/Renault scheme of instant battery swaps, allowing the batteries to be charged over time following the swap.
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