I don't know what chemistry exactly these cells are using, but in sodium-ion batteries, prussian blue analogs as they are called are common anode materials. Overcharging these cells can lead to a release of hydrogen cyanide gas, notoriously known as Zyklon B.
It has damped my enthusiasm for perusing it as a potential future home energy storage solution.
Do you have any link for the claim that overcharging can produce cyanide?
I have never heard such a thing and all the articles that I have seen about overcharging concluded that such batteries are much safer during overcharging than other kinds of batteries, the worst case effect being battery swelling.
In normal conditions, even during overcharging there are no obvious chemical reactions that could produce hydrogen cyanide.
Its metallic sodium. Its about 30 times more volatile than Lithium. We don't use metallic sodium for almost anything industrial because of this volatility. I assumed there would be some mixed Li-Na-ion batteries. A pure Na-ion battery is an explosive waiting to go off. Putting these in a car...seems rather like a poor choice unless you are a personal injury lawyer.
Or you could just have the batteries in a separate enclosure away from your house. I think I would be inclined to do this anyway, certainly for Lithium batteries given the possibility of fire.
hydrogen sulfide is not anywhere in the same category. When you consider failure you have to consider what is the most catastrophic possibility and if that is “this battery silently kills people” then you dont make it.
We also have to adulterate that methane with bitter smelling agents too warn people of the danger when there's a leak. The line into the house is also limited by a regulator to ensure the pressure is very low. If gas builds up in a battery, it's either going to leak out slowly or build up and leak out all at once.
> hydrogen sulfide is not anywhere in the same category.
It has the same LD50 dose as HCN. It literally _is_ just as bad. It routinely kills people on oil rigs because in lethal concentrations it immediately shuts off your nose.
How often do you hear about people getting poisoned by it from lead-acid batteries?
The only people with any significant amount of lead acid batteries on their property are off grid types who typically store them away from their primary domicile as a fire safety precaution.
Fast charging a car/chemical weapon in your garage isn't terribly appealing.
BYD / Denza z9 gt claim 10-70% in 5 mins, 97% in 9 mins. With a range of ~1000km this seems to crush these results? I don't know enough about this space to know if I am missing something here, but would love to know because something about this feels more exciting than i think i am grasping. anyone know?
> With a range of ~1000km this seems to crush these results
The 1000km range likely has more to do with the efficiency of the drivetrain and the aerodynamics of the car more than the battery tech. kWh is an absolute value that is fungible and the Denza has a 122.5 kWh battery pack, which means its getting 5mi/kWh. For perspective my Rivian R1S gets ~350 miles on a 135 kWh pack which is about 2.5mi/kWh (so about half that)
The only part of the battery tech that could affect range is the weight. Sodium batteries are typically much heavier than Li-on. I believe the Denza uses LFP, which means it's likely somewhere else on the car that they're gaining improvement in the range - not from the battery tech. That being said, the battery tech definitely affects the charge/discharge rates.
I see no charge rate numbers so there is no way to compare. however, these sodium batteries are cheaper, do not require lithium, and are operable at lower temperatures of -20C/-4F. Sounds like a bit of a win and opens the door for battery options in cars.
And the fire safety risks are significantly reduced (thermal runaway is much harder). They can also be transported and stored completely discharged, something not done with lithium ion batteries because of it degrades them much more than regular usage.
The sodium-ion batteries are said to work satisfactorily down to -40 Celsius = -40 Fahrenheit.
-20 Celsius just happens to be a temperature for which a retention ratio was specified in the parent article, and not the limit of the operation range.
This article is about a sodium-ion battery which is a different chemistry to the one BYD claimed those results on (that was LFP).
Sodium-ion is exciting because it has the potential to have less degradation over time, much less sensitivity to cold and less reliance on rare earth metals. Could also end up significantly cheaper. However it has struggled to reach the same energy densities and so hasn’t been practical thus far.
This seems like a big step towards it being a practical technology choice for certain models, if it bears out.
Well it is exciting, but not for the reasons you think. More like a Michael Bay movie exciting...there is nothing practical about this design. Most of the cost will be safety systems designed to prevent the battery from being exciting and even then a crash will likely set them off. Pure Na-ion probably isn't viable and certainly isn't viable in a car. Maybe mixing in some Na into the Li-ion to stretch the small amount of Lithium but even then you are significantly increasing the volatility of the battery.
This isn't a practical step, its an act of desperation from people who don't want to admit that large scale electrification is a dumb idea. We electrified everything that made sense to electrify a half century ago.
The range claims depend on the size of the battery pack. The Denza has a larger pack than what is quoted in the article. Also, the Chinese CLTC range ratings are overly optimistic with 1000km CLTC being ~820km WLTP or ~700km EPA.
Just remember, the US Na-Ion battery startup died last year with _products_ _in_ _warehouses_ just because it couldn't get a UL certification. All it needed was a bridge loan.
Why didn't a private investment company, even venture capital, extend them a bridge loan? It seems like the type of technology that could have decent returns in licensing fees.
I ask this question because it seems odd to someone in the software world so flooded with startups that the government would be expected to intercede on behalf of a startup.
Decent returns aren't enough for a risky investment, they need to be spectacular returns.
The benefit to the country as a whole is potentially large, but most of it wouldn't show up as profit for the company itself. I'm sure it would do quite well if it was successful, but the benefits to car manufacturers and to having this sort of technology on-shore would not translate into monetary returns on private investment. That's the sort of thing government intervention is good for.
People posting claims about EV charging time should be required to also post the size of cable required. And the grid capacity needed to provide their fast charging at a typical 8-bay charging site.
I don't know what chemistry exactly these cells are using, but in sodium-ion batteries, prussian blue analogs as they are called are common anode materials. Overcharging these cells can lead to a release of hydrogen cyanide gas, notoriously known as Zyklon B.
It has damped my enthusiasm for perusing it as a potential future home energy storage solution.
Do you have any link for the claim that overcharging can produce cyanide?
I have never heard such a thing and all the articles that I have seen about overcharging concluded that such batteries are much safer during overcharging than other kinds of batteries, the worst case effect being battery swelling.
In normal conditions, even during overcharging there are no obvious chemical reactions that could produce hydrogen cyanide.
For instance, at
https://pubs.acs.org/doi/10.1021/acsenergylett.4c02915
it is said that cyanide release can happen only at temperatures above 300 Celsius degrees. Such temperatures cannot be reached in normal conditions.
> Such temperatures cannot be reached in normal conditions
Thank you for the reasonable chuckle I got from this understatement of the day.
Its metallic sodium. Its about 30 times more volatile than Lithium. We don't use metallic sodium for almost anything industrial because of this volatility. I assumed there would be some mixed Li-Na-ion batteries. A pure Na-ion battery is an explosive waiting to go off. Putting these in a car...seems rather like a poor choice unless you are a personal injury lawyer.
Just wait until you find out about hydrogen sulfide from overcharged car batteries.
Also, I think HCN can be scrubbed by adding a special absorptive cap onto the battery.
Or you could just have the batteries in a separate enclosure away from your house. I think I would be inclined to do this anyway, certainly for Lithium batteries given the possibility of fire.
hydrogen sulfide is not anywhere in the same category. When you consider failure you have to consider what is the most catastrophic possibility and if that is “this battery silently kills people” then you dont make it.
We pipe methane into millions of homes. I don't think "this can silently kill people in the worst case" is enough to block something.
We also have to adulterate that methane with bitter smelling agents too warn people of the danger when there's a leak. The line into the house is also limited by a regulator to ensure the pressure is very low. If gas builds up in a battery, it's either going to leak out slowly or build up and leak out all at once.
Very much not an equal comparison.
> hydrogen sulfide is not anywhere in the same category.
It has the same LD50 dose as HCN. It literally _is_ just as bad. It routinely kills people on oil rigs because in lethal concentrations it immediately shuts off your nose.
How often do you hear about people getting poisoned by it from lead-acid batteries?
Not precisely the same:
https://en.wikipedia.org/wiki/Hydrogen_cyanide - 107 ppm (human, 10 min)
https://en.wikipedia.org/wiki/Hydrogen_sulfide - 600 ppm (human, 30 min)
https://en.wikipedia.org/wiki/Carbon_monoxide - 4000 ppm (human, 30 min)
These are "LCLo" values from the databoxes on those pages. More easily comparable numbers may be around somewhere.
The only people with any significant amount of lead acid batteries on their property are off grid types who typically store them away from their primary domicile as a fire safety precaution.
Fast charging a car/chemical weapon in your garage isn't terribly appealing.
BYD / Denza z9 gt claim 10-70% in 5 mins, 97% in 9 mins. With a range of ~1000km this seems to crush these results? I don't know enough about this space to know if I am missing something here, but would love to know because something about this feels more exciting than i think i am grasping. anyone know?
> With a range of ~1000km this seems to crush these results
The 1000km range likely has more to do with the efficiency of the drivetrain and the aerodynamics of the car more than the battery tech. kWh is an absolute value that is fungible and the Denza has a 122.5 kWh battery pack, which means its getting 5mi/kWh. For perspective my Rivian R1S gets ~350 miles on a 135 kWh pack which is about 2.5mi/kWh (so about half that)
The only part of the battery tech that could affect range is the weight. Sodium batteries are typically much heavier than Li-on. I believe the Denza uses LFP, which means it's likely somewhere else on the car that they're gaining improvement in the range - not from the battery tech. That being said, the battery tech definitely affects the charge/discharge rates.
I see no charge rate numbers so there is no way to compare. however, these sodium batteries are cheaper, do not require lithium, and are operable at lower temperatures of -20C/-4F. Sounds like a bit of a win and opens the door for battery options in cars.
And the fire safety risks are significantly reduced (thermal runaway is much harder). They can also be transported and stored completely discharged, something not done with lithium ion batteries because of it degrades them much more than regular usage.
The sodium-ion batteries are said to work satisfactorily down to -40 Celsius = -40 Fahrenheit.
-20 Celsius just happens to be a temperature for which a retention ratio was specified in the parent article, and not the limit of the operation range.
This article is about a sodium-ion battery which is a different chemistry to the one BYD claimed those results on (that was LFP).
Sodium-ion is exciting because it has the potential to have less degradation over time, much less sensitivity to cold and less reliance on rare earth metals. Could also end up significantly cheaper. However it has struggled to reach the same energy densities and so hasn’t been practical thus far.
This seems like a big step towards it being a practical technology choice for certain models, if it bears out.
"Sodium-ion is exciting because..."
Well it is exciting, but not for the reasons you think. More like a Michael Bay movie exciting...there is nothing practical about this design. Most of the cost will be safety systems designed to prevent the battery from being exciting and even then a crash will likely set them off. Pure Na-ion probably isn't viable and certainly isn't viable in a car. Maybe mixing in some Na into the Li-ion to stretch the small amount of Lithium but even then you are significantly increasing the volatility of the battery.
This isn't a practical step, its an act of desperation from people who don't want to admit that large scale electrification is a dumb idea. We electrified everything that made sense to electrify a half century ago.
The range claims depend on the size of the battery pack. The Denza has a larger pack than what is quoted in the article. Also, the Chinese CLTC range ratings are overly optimistic with 1000km CLTC being ~820km WLTP or ~700km EPA.
note that the quoted 170Wh/kg is about the same as currently available LiFePO4 cells and half that of the best available NMC cells
Just remember, the US Na-Ion battery startup died last year with _products_ _in_ _warehouses_ just because it couldn't get a UL certification. All it needed was a bridge loan.
And the government did nothing.
>And the government did nothing.
Why didn't a private investment company, even venture capital, extend them a bridge loan? It seems like the type of technology that could have decent returns in licensing fees.
I ask this question because it seems odd to someone in the software world so flooded with startups that the government would be expected to intercede on behalf of a startup.
In this case, Natron was focused on energy-storage for data centers, a sector which is ordinarily a prime recipient of government intervention.
Decent returns aren't enough for a risky investment, they need to be spectacular returns.
The benefit to the country as a whole is potentially large, but most of it wouldn't show up as profit for the company itself. I'm sure it would do quite well if it was successful, but the benefits to car manufacturers and to having this sort of technology on-shore would not translate into monetary returns on private investment. That's the sort of thing government intervention is good for.
Apparently, there were shenanigans from investors/creditors. So the company got quietly carved up instead of going through a bankruptcy auction.
I'm looking forward to the eventual investigational report.
BTW, the company was Natron Energy.
Starting to think that the American century of humiliation meme was prophetic.
One could argue that in that case, doing nothing was very much a choice.
"Never interrupt your enemy when he is making a mistake"
Think not,'what can my country do for me?', but, 'How can I further enrich Trump'
People posting claims about EV charging time should be required to also post the size of cable required. And the grid capacity needed to provide their fast charging at a typical 8-bay charging site.
Another better battery bulletin