Posted by breve 3 hours ago
Useful, but not a "breakthrough" in energy density. More like another good low-end option.
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.
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.
People say the same thing about Li-ion batteries yet they have proven to be significantly less likely to catch fire compared to ICE vehicles [1].
> 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.
I'm very curious to hear why you think this. If nothing else, the 'situation' with the Strait of Hormuz would seem to have shown the importance of energy independence achieved through large scale electrification. Individually, I couldn't go back to an ICE car or even garden tools, they're worse in every way.
1. https://www.mynrma.com.au/open-road/advice-and-how-to/unders...
If you want to replace FF there is exactly one solution, that's nuclear. Nothing else even scales to the point of making any difference at all. And you need to not just make electricity from the NPPs, but ammonia and some sort of synthetic hydrocarbon too. Anything else is a pipe dream from people who have never looked at the numbers nor learned the physics.
Stop acting like you care about this issue. You have never cared enough to learn about it, so until you do, stop spreading misinformation about how physics works.
PS I have driven an electric car for a decade, they are wonderful. Too bad there isn't enough Li for everyone to have one. Replacing Na with the Li just doesn't work for transport if you at all care about the people riding in the cars.
-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.
It has damped my enthusiasm for perusing it as a potential future home energy storage solution.
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.
Thank you for the reasonable chuckle I got from this understatement of the day.
Also, I think HCN can be scrubbed by adding a special absorptive cap onto the battery.
Cyanide could be released only at high temperatures, e.g. if the battery is opened and burned, not during normal operation, even if overcharging is not prevented, as it should.
The sulfuric acid from the traditional lead-acid car batteries is more dangerous than this.
Very much not an equal comparison.
Cyanide could be released only at high temperatures over 300 Celsius degrees.
During a fire, there are many other things in a car that can release toxic fumes easier than a sealed battery.
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?
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.
Fast charging a car/chemical weapon in your garage isn't terribly appealing.
The substances similar with Prussian blue are very stable. During charge and discharge, the ionic charge of iron ions varies between +2 and +3 and the structure of the electrode has spaces that are empty when the charge of the iron ions is +3 and they are filled with sodium ions when the charge of the iron ions is +2.
Both states of the electrode are very stable, being neutral salts. The composition of the electrolyte does not vary depending on the state of charge of the battery and it is also stable.
The only part of the battery that can be unstable is the other electrode, which stores neutral atoms of sodium intercalated in some porous material. If you take a fully charged battery, you cut it and you extract the electrode with sodium atoms, that electrode would react with water, but at a lower speed than pure sodium, so it is not clear how dangerous such an electrode would be in comparison with the similar lithium electrodes.
During charge-recharge cycles, a metallic electrode is likely to be degraded quickly.
So it is more likely that the reduced sodium atoms are intercalated in some porous electrode, e.g. of carbon, while at the other electrode the sodium ions are intercalated in some substance similar to Prussian blue.
The volatility of sodium does not matter, because it is not in contact with air or another gas, but only with electrolyte.
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.
While for cars sodium-ion batteries will never reach the energy per kilogram of the best lithium-ion batteries, for stationary use it makes absolutely no sense to use lithium batteries, because sodium batteries will become much cheaper when their production will be more mature, so they should always be preferred to lithium batteries.
Even for cars, sodium-ion batteries have a second advantage besides price, they retain their capacity and their charging speed down to much lower temperatures than lithium-ion batteries, so they will be preferred in cold climates.
I'm looking forward to the eventual investigational report.
BTW, the company was Natron Energy.
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.