4 ms·

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

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?

MisterTea 7mo ago
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.
- _aavaa_ 7mo ago
  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.
- adrian_b 7mo ago
  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.
  - nulltrace 7mo ago
    Operating at -40 is one thing, charging at -40 is another.
    - 8note 7mo ago
      i would have imagined that charging at -40 is easier than operating at -40.
    - adrian_b 7mo ago
      I have no idea how true this is, but the press releases claimed that both most of the capacity is retained down to -40 and that the charging speed is proportionally retain down to -40, and that this is the meaning of the operational range.
      - nulltrace 7mo ago
        Right, good to know.
    - Dylan16807 7mo ago
      When you're at a charger you can easily spare the 3-4% of battery capacity it takes to heat the pack by 40C. Less if you use a heat pump.
    - pjc50 7mo ago
      How many people let their ICE engine block get that cold?
      - nottorp 7mo ago
        For -40, the anecdote for combustion engines used to be that in Siberia you turn on the car's engine in november and off in march. For -20 though, it can happen each year in 4 season temperate climates and north of that.
cbg0 7mo 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.
IneffablePigeon 7mo ago
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.
- hunterpayne 7mo ago
  [flagged]
  - November_Echo 7mo ago
    > 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. 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/understanding-electric-vehicle-fires https://www.mynrma.com.au/open-road/advice-and-how-to/unders...
    - hunterpayne 7mo ago
      [flagged]
      - lazide 7mo ago
        Sodium ion batteries seem roughly as fire prone as LFP - which is to say, no particularly? What are you going on about?
mbesto 7mo ago
> 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.
- formerly_proven 7mo ago
  Ok, but the Rivian R1S is a particularly inefficient EV (2-2.5 mi/kWh = 31-25 kWh/100 km). 12.5 kWh/100 km is efficient but not outlandishly so considering these are likely CLTC ranges, which are higher than WLTP which are higher than EPA, and the car in question is not in fact a dumptruck.
- adrian_b 7mo ago
  Sodium-ion batteries will always be heavier than the best lithium-ion batteries, but for now they have the same energy per kilogram with LFP batteries. So they have 2 essential advantages over LFP, retention of capacity to much lower temperatures and their cost will become significantly lower when their production technology will be more mature, because they not only do not use lithium, but they also do not use other expensive substances, e.g. nickel or cobalt.
- masklinn 7mo ago
  > The only part of the battery tech that could affect range is the weight. Weight is a pretty low factor for cars, sub-percent (aging wheels did a comparison using a pickup empty versus loaded with a pallet of shingles, though with a more efficient vehicle the influence of weight probably shows up more). Energy density (amount of energy per unit of volume) is a much bigger factor than energy specificity (amount of energy per unit of mass), it means you can either cram more energy in the same volume for more range, or have a lower vehicle with better aero.

MisterTea 7mo ago

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.

_aavaa_ 7mo ago
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.
adrian_b 7mo ago
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.
- nulltrace 7mo ago
  Operating at -40 is one thing, charging at -40 is another.
  - 8note 7mo ago
    i would have imagined that charging at -40 is easier than operating at -40.
  - adrian_b 7mo ago
    I have no idea how true this is, but the press releases claimed that both most of the capacity is retained down to -40 and that the charging speed is proportionally retain down to -40, and that this is the meaning of the operational range.
    - nulltrace 7mo ago
      Right, good to know.
  - Dylan16807 7mo ago
    When you're at a charger you can easily spare the 3-4% of battery capacity it takes to heat the pack by 40C. Less if you use a heat pump.
  - pjc50 7mo ago
    How many people let their ICE engine block get that cold?
    - nottorp 7mo ago
      For -40, the anecdote for combustion engines used to be that in Siberia you turn on the car's engine in november and off in march. For -20 though, it can happen each year in 4 season temperate climates and north of that.

cbg0 7mo 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.

IneffablePigeon 7mo ago

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.

hunterpayne 7mo ago
[flagged]
- November_Echo 7mo ago
  > 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. 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/understanding-electric-vehicle-fires https://www.mynrma.com.au/open-road/advice-and-how-to/unders...
  - hunterpayne 7mo ago
    [flagged]
    - lazide 7mo ago
      Sodium ion batteries seem roughly as fire prone as LFP - which is to say, no particularly? What are you going on about?

mbesto 7mo ago

> 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.

formerly_proven 7mo ago
Ok, but the Rivian R1S is a particularly inefficient EV (2-2.5 mi/kWh = 31-25 kWh/100 km). 12.5 kWh/100 km is efficient but not outlandishly so considering these are likely CLTC ranges, which are higher than WLTP which are higher than EPA, and the car in question is not in fact a dumptruck.
adrian_b 7mo ago
Sodium-ion batteries will always be heavier than the best lithium-ion batteries, but for now they have the same energy per kilogram with LFP batteries. So they have 2 essential advantages over LFP, retention of capacity to much lower temperatures and their cost will become significantly lower when their production technology will be more mature, because they not only do not use lithium, but they also do not use other expensive substances, e.g. nickel or cobalt.
masklinn 7mo ago
> The only part of the battery tech that could affect range is the weight. Weight is a pretty low factor for cars, sub-percent (aging wheels did a comparison using a pickup empty versus loaded with a pallet of shingles, though with a more efficient vehicle the influence of weight probably shows up more). Energy density (amount of energy per unit of volume) is a much bigger factor than energy specificity (amount of energy per unit of mass), it means you can either cram more energy in the same volume for more range, or have a lower vehicle with better aero.