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Australia first to test new lithium-sulphur batteries

newscientist.com

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Re: Australia first to test new lithium-sulphur batteries

#41

Post by NopeNotToday »

ajuc wrote: post #17
Retric wrote: post #16

Earlier quoted context omitted.

200 charge cycles at 4x the storage = 800 lithium ion charge cycles. That’s easily competitive. Put another way if your getting 300 miles of range a current EV that’s 300 x4 x200 = 240,000 miles.

Only if you change your habits to maximize the lifetime of the batteries. For example avoid charging the car every night and instead charge it for a few nights after it's completely empty.

Then divide the battery pack into two (or more) packs. The battery controller then uses one pack to exhaustion, then switches over to the other pack. Normal charging will only charge fully depleted packs. This would reduce maximum range. So add in a charging override for an occasional max distance drive.

Re: Australia first to test new lithium-sulphur batteries

#42

Post by emayljames »

hanniabu wrote: post #20
brink wrote: post #12

Am I correct in assuming that a four-fold capacity in electric vehicles is coming? That will likely decimate oil dependency.

> That will likely decimate oil dependency Until subsidies are increased... Pet peeve of mine is how big business like to champion capitalism, but when they start failing they no longer like those rules and want government help to stay relevant and afloat.

Socialism for the rich, "the (not so) free market" for the peasantry.

Re: Australia first to test new lithium-sulphur batteries

#43

Post by nickserv »

vocatus_gate wrote: post #22
brink wrote: post #12

Am I correct in assuming that a four-fold capacity in electric vehicles is coming? That will likely decimate oil dependency.

Reduce it by a tenth?

I know you're referring to the original meaning of the term, but a 10% decrease in global oil consumption in the transportation sector would be a great accomplishment. Not nearly enough of course, but so far we haven't even been able to flatline.

Re: Australia first to test new lithium-sulphur batteries

#44

Post by audunw »

ajuc wrote: post #17
Retric wrote: post #16

Earlier quoted context omitted.

200 charge cycles at 4x the storage = 800 lithium ion charge cycles. That’s easily competitive. Put another way if your getting 300 miles of range a current EV that’s 300 x4 x200 = 240,000 miles.

Only if you change your habits to maximize the lifetime of the batteries. For example avoid charging the car every night and instead charge it for a few nights after it's completely empty.

What? No.. if you go from 80% to 60% back to 80%, that's not considered a full cycle.

You seem to carry a misconception from an older battery chemistry (I don't remember which, but it was common in early cell phones), where it was supposedly better to discharge the battery completely before charging again.

Most chemistries are not like that, as far as I know. In fact, with li-ion it's better to charge every night, if your EV battery has a good buffer, or you can configure it to charge to 80% except for days where you'll actually need 100%.

Maintaining 99% for 200 cycles seem pretty good to me. Possibly better than Li-ion? It depends on how fast the battery degrades after that. But I'm pretty sure my EV lost its first 1% way before 200 cycles.

Re: Australia first to test new lithium-sulphur batteries

#45

Post by philipkglass »

However, lithium-sulphur batteries may face similar ethical problems to lithium-ion batteries. The metal oxides in lithium-ion batteries are typically nickel, cobalt or manganese, which are expensive and diminishing in natural stores. They also have associated ethical problems: a significant proportion of cobalt is sourced by child miners in the Democratic Republic of the Congo, for example.

“In order to have much cheaper energy and more ethical batteries, we need a radically new energy storage system,” says Shaibani. The researchers will further test battery prototypes with a view to manufacturing them commercially in Australia in coming years.

It appears that Shaibani is saying that their new battery chemistry is an example of a radically improved battery that removes ethical problems while it improves energy density. The way the New Scientist article is written, that preceding paragraph makes it sound like Shaibani's new chemistry still needs improvements to remove cobalt.

There is already no nickel, manganese, or cobalt in this new lithium-sulfur cathode (nor in most lithium-sulfur cathodes). See Table S1 in the supplementary table for elemental analysis:

https://advances.sciencemag.org/content/advances/suppl/2019/...

Re: Australia first to test new lithium-sulphur batteries

#46

Post by audunw »

fooqux wrote: post #34
Enginerrrd wrote: post #31

Earlier quoted context omitted.

As I understand it, this is a terrible thing to do to lithium ion batteries. NiCad batteries were like that, but li-ion shouldn't be allowed to go below 20% if you're interested in longevity.

I thought this was basically a non-issue as the battery circuitry would kill power before it got past that point. Or does that just stop it from emptying completely?

I think it depends on the application where the circuitry cuts off. Almost all applications will have circuitry that cuts power before the cell dies completely. You even have individual 18650 cells that have such a circuit built in (for flash-lights and so on)

But increased battery degradation starts way before you hit that limit. At least with cell phones, that tend to push battery cells pretty hard, you'll have pretty bad degradation when discharging to 0%. I think most EVs have a higher cut-off, and most people don't discharge EVs to near 0% anyway.

Re: Australia first to test new lithium-sulphur batteries

#47

Post by audunw »

JoeAltmaier wrote: post #26
AnthonyMouse wrote: post #15

Earlier quoted context omitted.

What makes electric cars viable isn't that batteries have anywhere near the energy density of gasoline, it's that if you use them, you get to replace half a ton of engine, transmission, alternator, fuel pump, emissions and exhaust with a This naturally makes battery improvements a huge win. If you double power density you can cut the weight of the battery by more than half for the same range, since not only do you ge…

Nowhere near. The Tesla battery pack is 1000 lbs. There are entire cars that don't weigh that. Race car engine is 200lbs. And battery packs have cooling systems too. So no savings there. Specific energy (watts-hours per kilogram) is the entire ballgame with batteries and transportation.

> And battery packs have cooling systems too. So no savings there.

That's not quite true. At the very least, EVs require a much smaller radiator, if it has one at all. Some EVs don't have cooling at all (Nissan Leaf), although that increases degradation in hotter climates.

I think his point stands.. An ICE engine weight at least 200lb. With transmission it could be up to 600lb. The Model S engine is 70lbs.

You "only" need to halve the weight of a Model S battery for the drivetrain+battery to be in the same ballpark as an ICE drivetrain as far as I can tell.

Re: Australia first to test new lithium-sulphur batteries

#48

Post by WhompingWindows »

brink wrote: post #12

Am I correct in assuming that a four-fold capacity in electric vehicles is coming? That will likely decimate oil dependency.

Best not to assume anything about battery breakthroughs - there's one reported every week.

Many companies are on the fore-front of batteries...if this chemistry is legit and available, you will know when Tesla or LG chem or one of the big players buys this groups' IP.

Re: Australia first to test new lithium-sulphur batteries

#49

Post by zackmorris »

JoeAltmaier wrote: post #10

Lithium-Sulphur has high energy per kilogram which makes it good for transportation. Also high energy per dollar to manufacture which makes it good for grid storage (where weight and size don't matter too much, but cost does). At the nominal rate of 750 amp hours per kilogram for lithium-Sulphur is well above normal lithium-ion batteries. But compared to gasoline, it raises the bar from 1% vs gas, to 2%. Do I have th…

Gasoline has about 33 kWh/kg (118.8 MJ/kg):

https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent

Unfortunately, internal combustion engines have a pathetic fuel economy since they run at low temperatures (around the boiling point of water). All heat engines are limited by the Carnot efficiency, which improves with higher temperature differential. In practice, other cycles like Otto, Diesel, Rankine and Brayton are lower than Carnot and improve with things like higher compression ratio:

  Carnot efficiency = (T.hot - T.cold)/T.hot
  where T is in Kelvin
https://en.wikipedia.org/wiki/Thermal_efficiency#Carnot_effi...

A low compression, naturally aspirated engine running at room temperature with nothing done to improve fuel economy runs at (373.15 - 298)/373.15 = 20% efficiency. I've heard figures as low as 8% for rubber meets the road efficiency in older passenger cars, which I believe, since we drove a ’68 Cadillac that got 5 mpg back in the 90s when gas was under $1 per gallon.

The best modern high compression engines typically achieve 25-30% efficiency at best. So I figure there are about 8-10 kWh/kg (28.8-36 MJ/kg) available in gasoline with modern vehicles. Cars built before ‘70s efficiency standards would be more like 2.5-3 kWh/kg (9-10.8 MJ/kg).

Unfortunately, it's not just that people don't care how ridiculously inefficient their vehicles are, it's that politicians corrupted by the fossil fuel industry and vehicle manufacturing lobbies never stop conspiring to lower efficiency standards:

https://www.vox.com/2019/4/6/18295544/epa-california-fuel-ec...

But I digress.

Electric motors typically run at about 95% efficiency, so we can probably assume 90% efficiency to the road. That’s over 10 times more efficient than classic cars!

Looks like Tesla lithium ion batteries are 0.254 kWh/kg (0.914 MJ/kg):

http://theconversation.com/teslas-batteries-have-reached-the...

Which is very close to the theoretical ideal for lithium ion of 0.294 kWh/kg (1.058 MJ/kg):

https://en.wikipedia.org/wiki/Energy_density#Tables_of_energ...

I'm having trouble finding energy densities for the new lithium sulfur batteries:

https://advances.sciencemag.org/content/6/1/eaay2757

https://advances.sciencemag.org/content/advances/6/1/eaay275...

I'm going to use their low number of 1200 mAh/kg, working between 1.7 and 2.5 V, so averaging 2.1 V (which is very inaccurate without integration), we can call it about 2.520 kWh/kg (9.072 MJ/kg). That would be about 10 times denser than Tesla batteries. Maybe they are estimating half the density in the real world due to packaging or something, in order to arrive at their "5 times longer battery life" headline.

So anyway, the real numbers are:

  Gasoline       33 kWh/kg    118.8 MJ/kg   (ideal)
  Gasoline       8-10 kWh/kg  28.8-36 MJ/kg (actual for modern vehicle)
  Gasoline       2.5-3 kWh/kg 9-10.8 MJ/kg  (actual for pre-70s vehicle
  Lithium sulfur 2.520 kWh/kg 9.072 MJ/kg   (ideal)
  Lithium sulfur 1.260 kWh/kg 4.536 MJ/kg   (actual)
  Lithium ion    0.294 kWh/kg 1.058 MJ/kg   (ideal)
  Lithium ion    0.254 kWh/kg 0.914 MJ/kg   (actual for Tesla)
My numbers might be off by a fair amount, but the important thing here is to think in orders of magnitude. Lithium sulfur is halfway to the energy density of classic cars and aircraft, with all the positives, like electric motors having 10 times the power as gas engines by weight, much higher torque, and substantially higher endurance/simplicity.

Re: Australia first to test new lithium-sulphur batteries

#50

Post by Gibbon1 »

brink wrote: post #12

Am I correct in assuming that a four-fold capacity in electric vehicles is coming? That will likely decimate oil dependency.

Two thoughts of mine.

A twofold improvement in capacity would kill gasoline cars dead. That's 300 miles of range out of a 600lb battery. Adding up the weights of various components the electric car would weight about the same as a gasoline one.

While the failure modes of metal lithium anode batteries are terrifying that's probably okay for grid applications. Difference between a cell phone stuffed under a pillow and a battery in a concrete vault at at substation.

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