A quick Google search claims that Tesla’s “4680” battery has an energy density of 244 to 296 Wh/kg. I don’t know enough about the industry to know if these numbers are right. If they are, seems like BYD is pretty far behind Tesla.
Anyone know if this is right? Or what I’m missing?
4680 is a cylindrical cell format, the number you quoted refers to the cell itself, when packaged into a battery with busbars, cooling, etc., the gravimetric density on pack level for model 3 is around 125Wh/kg. the number listed by BYD is 150Wh/kg pack level density. the cells themselves are probably around 200-250, but they require less packaging effort due to the fact that the cell housing for prismatic cells already incorporates various mechanical and safety features.
i haven’t checked any of the numbers nor have i seen 3rd party analyses, but it definitely follows the trend: prismatics keep getting better and they might ultimately win the race once we get to solid state and thermal management “solves itself”
Tesla uses some of the current gen BYD batteries in their low end models.
So they're good enough for some uses, but energy density was a stat they trailed current battery tech on. Any improvement in that stat just expands the area where the trade off makes sense.
This article claims a quarter of Model Y in Germany use the LFP battery from BYD, and covers the pros and cons:
You are talking a different (nickel-cobalt-manganese, or NCM) battery chemistry. This is also a type of a Li-ion battery but has a number of advantages and disadvantages compared to LFP battery chemistry (which is just another type of Li-ion batteries).
As you mentioned, NCM has much higher power density, and allows charge/discharge at higher rates than LFP. But LFP technology is much better in terms of safety, stability, low degradation over time and much longer overall lifetime with high number of charge-discharge cycles.
You are not wrong. LFP is mostly for small, compact low-range EVs, so its low energy cell density under ~160Wh/kg is sufficient.
Most mid/high end EVs with longer range or power needs use high-nicke/energy NCM/NCA. de facto standard such as NCM811 has over ~270Wh/kg while the cutting edge ones, NCM9, from SK On ~300Wh/kg and already deployed in Ford F-150, Hyundai Ioniq and Kia EV9.
Hyundai Ioniq 5 2024 Refresh just received the chemistry upgrade from NCM811 to NCM9 (or in this particular instance 88% Nickel) which in turn increased the capacity by 10%.
As for Tesla's 4860, it seems like they are still struggling with low production output. Tesla had promised much better efficiency figures years ago, but doesn't seem to live up. LG is however rumored to have finished developing their 4860 and will produce them later this year (alledgedly for Tesla).
It was NCM for a reason: LFP was patented in the USA. The patents applied to China too of course, but China ignored them. But now patent has expired Tesla can sell LFP into the USA legally it's happening.
Off topic rant. This is a fine example of the patent system hurting rather than helping a country. It's not the idea of rewarding the person taking a risk getting a reward for it that's the problem, it's more than a single term (20 years) works for all areas. It's probably fine for pharmacy. But that moves at a snails pace, and generally patents don't overlap. Batteries don't move much faster than pharmacy, but nonetheless the USA has almost no hope of overtaking China in LFP now and the USA in invented the technology. In fast moving industries like computers the current patent system the current patent is a disaster.
Interestingly, IP enforcement relies on globalization, which has been on the wane since Xi cemented his autocratic powers and the US began its trade war under the Trump administration
Anyone know if this is right? Or what I’m missing?