The article is short on information on the battery itself but thankfully there is a Wikipedia entry for it:
> The heart of any electric car is the battery.
one way to look at it, sure.
> It makes up around 40% of the value…
well, that seems a bit arbitrary, but as not an expert myself, seems… fine.
> …and we rely on it to keep us moving.
well, sure, it is a required part of the car. we also rely on the wheels to keep us moving.
> And yet we know very little about them.
what in the actual…
Of course he was talking about a much lower level than you need to understand when it comes to actually using them.
There are actually a lot of things we know how to deal with when it comes to engineering but have a poor grasp of the low level details. There was a great example in the Feynman Lectures where he says this about friction (Volume 1, section 12-2):
> It is quite difficult to do accurate quantitative experiments in friction, and the laws of friction are still not analyzed very well, in spite of the enormous engineering value of an accurate analysis. Although the law F=μN is fairly accurate once the surfaces are standardized, the reason for this form of the law is not really understood. To show that the coefficient μ is nearly independent of velocity requires some delicate experimentation, because the apparent friction is much reduced if the lower surface vibrates very fast. When the experiment is done at very high speed, care must be taken that the objects do not vibrate relative to one another, since apparent decreases of the friction at high speed are often due to vibrations. At any rate, this friction law is another of those semiempirical laws that are not thoroughly understood, and in view of all the work that has been done it is surprising that more understanding of this phenomenon has not come about. At the present time, in fact, it is impossible even to estimate the coefficient of friction between two substances.
That was written around 60 years ago. Anyone here happen to know if it still holds?
Not really the same question but I attended a talk by some top tribologists at my uni and I asked them if friction really was independent of contact area (as F=μN would suggest), their reply was that it roughly was, but not really if you were very precise or varying parameters. It would appear that the equation is a good approximation, like classical Newtonian physics.
the math produces results that are understood but not, because the math is calculating with some implicit inclusions, and things get weird when you start explicitly including.
the answers make sense, but not quite for the questions being asked. (but the answers are valid for a question, and more importantly, immediately useful for making dollars.)
unfortunately the vagueness of this will likely irritate a doctor. it certainly did years ago.
> "Reaction rates at spatially heterogeneous, unstable interfaces are notoriously difficult to quantify, yet are essential in engineering many chemical systems, such as batteries and electrocatalysts..."
https://www.nature.com/articles/s41586-023-06393-x
It's a much harder problem than working with pure crystals or gas-phase molecules or similar, which makes sense, as a half-discharged battery is a very messy system at the molecular-atomic level. See also news story on the above article:
> “We discovered at the nano scale that variation of the carbon coating thickness directly controls the rate, which is something you could never figure out if you didn't have all of this modeling and image analysis,” Bazant says.
https://news.mit.edu/2023/pixel-analysis-yields-insights-lit...
So, the field seems to be progressing steadily - and more funding for fundamental solid-state materials science research makes sense, too.
> But BYD is also a car maker in its own right
Yeah, it's actually the largest electric car manufacturer in the whole world.
Found it https://northvolt.com/articles/northvolt-sodium-ion/
> The space utilization of the battery pack is increased by over 50% compared to most conventional lithium iron phosphate block batteries.
> BYD claims that, in the nail penetration test, the Blade Battery emitted no smoke or fire after being penetrated, and its surface temperature reached only 30 to 60 °C (86 to 140 °F). It is currently the only power battery in the world that can safely pass the test.
Reducing volume by 33% and mostly eliminating fire risks are both huge wins, if true. Doing it in a standard form factor that can be reused across future vehicle platforms is an even bigger deal.
This is mostly a packaging and cooling innovation. Round cells are inefficient from a density standpoint, but the empty space between cylinders allows heat to escape.
BYD's approach to electric cars in China is modest range and lots of charging stations. Average distance driven per day in the US is 60 km. Current BYD vehicles all have a range over 200km. Same niche as Chevrolet, or what Chevy used to be - a seller of basic transportation.
It's a worry that, in the last few years, US manufacturers have gone way overboard on too much car per car, to the point that most American workers can't afford current vehicles.
Things like the Nissan Leaf have been widely available in the US for nearly a decade now, with battery sizes from 20-40kWh. There's a market for it, but it's niche. The reality is just that EVs will never truly become mainstream in the US until there's a >60kWh budget vehicle that sells out the door under $25k. The distances are simply too much for anything less to be viable for people outside of a major metro area.
> BYD claims that, in the nail penetration test, the Blade Battery emitted no smoke or fire after being penetrated, and its surface temperature reached only 30 to 60 °C (86 to 140 °F). It is currently the only power battery in the world that can safely pass the test.
> In addition, it successfully passed an extreme safety test that saw it being rolled over by a 46-tonne heavy-duty truck[citation needed].
> The Blade Battery also passed other extreme test conditions, such as being crushed, bent, being heated in a furnace to 300 °C (572 °F) and overcharged by 260%. None of these resulted in a fire or explosion.
None of that sounds like big leaps of progress to you?
More on-topic, I wonder if the battery is fully functional with that 260% overcharge. Could be interesting if you can tell the battery (controller) “yes I accept the 1% point extra wear, please enable overcharge mode” for a really long trip that won’t have charging stations.
Overcharge doesn't mean that the battery can store additional capacity beyond its design limits. It just means that the battery won't be damaged or catch on fire if you continue to put electricity in it after it is already full.
The last of the patents on LFP expired last year. Up until then, the patent holders made a deal where Chinese companies could produce the cells, but not export them.
So that appears to be the reason for so much investment in the space in recent times.
China did negotiate a deal with a patent consortium in Suisse to license LFP royalty-free for all domestic use. But then I wonder what the point was, since all foreign battery makers/patent holders such as LG (NCM), Panasonic (NCA) were required to give up their IP Rights in order to acces China's NEV market, or China would have ignored their IP Rights anyway.
>> So that appears to be the reason for so much investment in the space in recent times. <<
Sure, there has been some improvement, but LFP is still mostly limited to entry-level, low-range EVs. The recent rise of LFP is largely attributable to the various COVID related auto component shortages and price spike in battery raw materials past few years. The average price of lithium however plunged by some 80% since last November and once 400+GWh new production capacity come up in the US, I suspect that LFP won't be as competitive.
Cell chemistry is just one part of the equation. Better (lighter) pack designs are equally important to increasing overall energy density, safety, and reliability.
Tesla has been primarily working with Panasonic's NCA for over a decade now. LG's NCM was added only after 2020 for their Long Range models in China/EU.