7 ms·

Innovation of the Year: BYD Blade Battery

109 points by hunglee2 3y ago

_Microft 3y ago
The article is short on information on the battery itself but thankfully there is a Wikipedia entry for it: https://en.m.wikipedia.org/wiki/Blade_Battery https://en.m.wikipedia.org/wiki/Blade_Battery
- catchnear4321 3y ago
  thanks for the link, the “article” can’t even keep it on the rails for the intro. > 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…
  - tzs 3y ago
    I remember in a solid state chemistry MOOC I took, from a professor who was a lithium battery researcher, the professor did mention in passing that we actually don't have a really good understanding of lithium batteries. 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?
    - user_7832 3y ago
      > 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.
    - _a_a_a_ 3y ago
      Apparently even solubility of compounds in various solvents is empirically derived because there's no reliable theoretical model of this in chemistry/physics. (AIUI anyway)
      - catchnear4321 3y ago
        not to get too leaky, and this is a bit dated, but… 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.
    - photochemsyn 3y ago
      At some point, scale-wise, friction problems become electrochemical rate problems, I suppose. See this recently published research article on lithium iron phosphate batteries, opening: > "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 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-lithium-ion-batteries-0913 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.
  - joosters 3y ago
    And: > But BYD is also a car maker in its own right Yeah, it's actually the largest electric car manufacturer in the whole world.
    - eunos 3y ago
      BYD actually started as a battery maker.
    - DoesntMatter22 3y ago
      Only if you consider a hybrid to be an electric car. Tesla is still bigger on BEVs
      - xbmcuser 3y ago
        They are expected to get ahead of Tesla end of this year.
        DoesntMatter22 3y ago
        Most things I've seen say next year. Regardless, it's not a fact that they are the biggest yet.
- deleted 3y ago
  [deleted]
- throwawaymaths 3y ago
  Lfp chemistry is not that innovative -- it's in use in homes for sure and I think also tesla uses them. Given the breathlessness of the article I expected sodium batteries or something
  - Voultapher 3y ago
    Wasn't there news recently that a big supplier started selling commercial sodium batteries? Found it https://northvolt.com/articles/northvolt-sodium-ion/ https://northvolt.com/articles/northvolt-sodium-ion/
  - conradev 3y ago
    Better cell design and better chemistry both contribute to safety, and I think the Blade’s primary innovation here is their cell design
    - hedora 3y ago
      From the wikipedia article, it's all about the form factor: > 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.
      - Animats 3y ago
        This is a lithium iron phosphate battery. Safer chemistry than lithium-ion, but heavier. There's a lot be said for lithium iron phosphate. Once we have millions of old, badly maintained electric cars on the road, it's better if they're not using a battery technology prone to fire. 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.
ggm 3y ago
Panasonic canned battery production is highly efficient and semi flow based, long lengths of materials can be assembled like lasagne and then rolled up into cigars and well.. canned. It's a centuries old model since leclanche cells. If this one is amenable to a mass production model it's great.
- t_tsonev 3y ago
  This efficiency doesn't translate to EV battery packs. They require thousands of welds, the pack contains ends up with plenty of empty space and it's impractical to replace parts of it.
  - audunw 3y ago
    For LFP you can supposedly pack the cells very tight, as they require less thermal management if I understand correctly. And you’re HAVE to do this optimisation for LFP to have decent pack level energy density. For Li-ion cells, you need that empty space for cooling of the battery cells anyway. And Tesla has demonstrated that cylindrical cells can contribute to the structure in a structural battery pack. So for Li-ion I don’t think cylindrical cells are worse. There’s just different trade-offs. But yeah, one of downsides it can be hard or impossible to replace individual cells if they have problems.
    - esturk 3y ago
      It doesn't matter how much you "pack the cells very tight", there's a geometrical limit here.[1] And in practice, you'll have modules of sections of the battery for repairing which drops the efficiency to below 90%. [1] https://en.wikipedia.org/wiki/Circle_packing#Densest_packing https://en.wikipedia.org/wiki/Circle_packing#Densest_packing
- doubloon 3y ago
  Panasonic used to be called Matsushita and they pioneered the non-cylindrical "prismatic" nickel metal hydride battery when they were working with Toyota on the Prius. It did not go this far, it was more like 6 pouch-cells aligned in a blade shape, but still not alien to them I bet. Also they transferred a lot of that tech to China over time so it is quite possible BYD grew off the Panasonic tradition. I'm betting Panasonic could do a Blade in mass production if they wanted.
ksec 3y ago
The problem is BYD's LFP battery energy density is only 150 Wh/kg. Compared to 260 in something like a Tesla.
- reitzensteinm 3y ago
  Are you saying Tesla's LFP is 260 Wh/kg, or are you comparing across chemistries?
  - gridder 3y ago
    the latter
    - oittaa 3y ago
      Even LFPs are getting better all the time. Energy density in Cybertruck at the pack level is something like 170 Wh/kg with the latest 4680 cells.
      - p1mrx 3y ago
        Isn't the Cybertruck using regular lithium ion? That shows how immature the 4680 production process is, if they can barely compete with LFP, though some of the weight is contributing to the structure of the vehicle.
- fiftyfifty 3y ago
  Tesla is already using BYD’s blade batteries in the Model Y in Europe: https://insideevs.com/news/668659/tesla-model-y-batteries-byd-versus-catl/amp/ https://insideevs.com/news/668659/tesla-model-y-batteries-by...
  - tooltalk 3y ago
    With the pack level density of ~140Wh/kg. CATL is Tesla's primary LFP supplier -- BYD was added earlier this year. The key sellig point here is the cost.
baybal2 3y ago
Preemptively posting what is people's biggest confusion: Battery cell energy density is not the same as the whole battery pack energy density. Western battery cell manufacturers chased the specific energy density figure, and in the process they decided to save weight on the casing, and electrodes as much as possible, resulting in very fragile battery cells. To avoid 18650 cells being crushed, you will need a lot of structural reinforcements added to the battery pack, consuming weight. Even with all of that, tiny, individually 18650 cells waste a lot of weight on the cell casing, on things like welds, terminals, relief valves, thermal interface material etc. Bigger cells invariably have better casing to active material ratio, but the casing mass is still "useless. Blade battery reverses all of above, and intentionally uses very strong, and thermally conductive case, to make the casing weight to contribute to battery pack mechanical strength. LFP cathode feels very well at high temperatures, and has very high resistance to mechanical expansion during charge. This allows to make LFP cells much bigger than cells with other chemistries, and removes the need for liquid cooling system inside the battery pack, greatly saving weight.
doubloon 3y ago
alot more detail here https://www.sae.org/news/2021/10/byds-blade-runner https://www.sae.org/news/2021/10/byds-blade-runner would love to be corrected here but if i understand they basically did away with the idea of "modules of cells" and just have the entire pack made of hundreds of cells directly attached to the bus. which ironically is more like the Prius battery (28 'prisms') than the Tesla battery (cylndrical). also seems to me like, they maybe dont have to flood the entire thing with disgusting pink foam, maybe you could have a halfway chance of replacing a single cell if it went bad.
ryzvonusef 3y ago
https://twitter.com/jimfarley98/status/1732584621890482514 https://twitter.com/jimfarley98/status/1732584621890482514 > They weren't joking. We received the document today, dated Dec. 5th. Thanks, @ElonMusk. Great for the industry!
m463 3y ago
Offering awards for things is kind of self-serving for a publication. Bet it drives up click rates. I remember reading something once, where famous people should carefully vet who they accept awards from. An award might just be a sneak way of getting some relevant person to speak at an event for free or a nominal cost.

109 points by hunglee2 3y ago

The article is short on information on the battery itself but thankfully there is a Wikipedia entry for it: https://en.m.wikipedia.org/wiki/Blade_Battery https://en.m.wikipedia.org/wiki/Blade_Battery

catchnear4321 3y ago
thanks for the link, the “article” can’t even keep it on the rails for the intro. > 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…
- tzs 3y ago
  I remember in a solid state chemistry MOOC I took, from a professor who was a lithium battery researcher, the professor did mention in passing that we actually don't have a really good understanding of lithium batteries. 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?
  - user_7832 3y ago
    > 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.
  - _a_a_a_ 3y ago
    Apparently even solubility of compounds in various solvents is empirically derived because there's no reliable theoretical model of this in chemistry/physics. (AIUI anyway)
    - catchnear4321 3y ago
      not to get too leaky, and this is a bit dated, but… 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.
  - photochemsyn 3y ago
    At some point, scale-wise, friction problems become electrochemical rate problems, I suppose. See this recently published research article on lithium iron phosphate batteries, opening: > "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 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-lithium-ion-batteries-0913 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.
- joosters 3y ago
  And: > But BYD is also a car maker in its own right Yeah, it's actually the largest electric car manufacturer in the whole world.
  - eunos 3y ago
    BYD actually started as a battery maker.
  - DoesntMatter22 3y ago
    Only if you consider a hybrid to be an electric car. Tesla is still bigger on BEVs
    - xbmcuser 3y ago
      They are expected to get ahead of Tesla end of this year.
      - DoesntMatter22 3y ago
        Most things I've seen say next year. Regardless, it's not a fact that they are the biggest yet.
deleted 3y ago
[deleted]
throwawaymaths 3y ago
Lfp chemistry is not that innovative -- it's in use in homes for sure and I think also tesla uses them. Given the breathlessness of the article I expected sodium batteries or something
- Voultapher 3y ago
  Wasn't there news recently that a big supplier started selling commercial sodium batteries? Found it https://northvolt.com/articles/northvolt-sodium-ion/ https://northvolt.com/articles/northvolt-sodium-ion/
- conradev 3y ago
  Better cell design and better chemistry both contribute to safety, and I think the Blade’s primary innovation here is their cell design
  - hedora 3y ago
    From the wikipedia article, it's all about the form factor: > 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.
    - Animats 3y ago
      This is a lithium iron phosphate battery. Safer chemistry than lithium-ion, but heavier. There's a lot be said for lithium iron phosphate. Once we have millions of old, badly maintained electric cars on the road, it's better if they're not using a battery technology prone to fire. 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.

ggm 3y ago

Panasonic canned battery production is highly efficient and semi flow based, long lengths of materials can be assembled like lasagne and then rolled up into cigars and well.. canned. It's a centuries old model since leclanche cells. If this one is amenable to a mass production model it's great.

t_tsonev 3y ago
This efficiency doesn't translate to EV battery packs. They require thousands of welds, the pack contains ends up with plenty of empty space and it's impractical to replace parts of it.
- audunw 3y ago
  For LFP you can supposedly pack the cells very tight, as they require less thermal management if I understand correctly. And you’re HAVE to do this optimisation for LFP to have decent pack level energy density. For Li-ion cells, you need that empty space for cooling of the battery cells anyway. And Tesla has demonstrated that cylindrical cells can contribute to the structure in a structural battery pack. So for Li-ion I don’t think cylindrical cells are worse. There’s just different trade-offs. But yeah, one of downsides it can be hard or impossible to replace individual cells if they have problems.
  - esturk 3y ago
    It doesn't matter how much you "pack the cells very tight", there's a geometrical limit here.[1] And in practice, you'll have modules of sections of the battery for repairing which drops the efficiency to below 90%. [1] https://en.wikipedia.org/wiki/Circle_packing#Densest_packing https://en.wikipedia.org/wiki/Circle_packing#Densest_packing
doubloon 3y ago
Panasonic used to be called Matsushita and they pioneered the non-cylindrical "prismatic" nickel metal hydride battery when they were working with Toyota on the Prius. It did not go this far, it was more like 6 pouch-cells aligned in a blade shape, but still not alien to them I bet. Also they transferred a lot of that tech to China over time so it is quite possible BYD grew off the Panasonic tradition. I'm betting Panasonic could do a Blade in mass production if they wanted.

ksec 3y ago

The problem is BYD's LFP battery energy density is only 150 Wh/kg. Compared to 260 in something like a Tesla.

reitzensteinm 3y ago
Are you saying Tesla's LFP is 260 Wh/kg, or are you comparing across chemistries?
- gridder 3y ago
  the latter
  - oittaa 3y ago
    Even LFPs are getting better all the time. Energy density in Cybertruck at the pack level is something like 170 Wh/kg with the latest 4680 cells.
    - p1mrx 3y ago
      Isn't the Cybertruck using regular lithium ion? That shows how immature the 4680 production process is, if they can barely compete with LFP, though some of the weight is contributing to the structure of the vehicle.
fiftyfifty 3y ago
Tesla is already using BYD’s blade batteries in the Model Y in Europe: https://insideevs.com/news/668659/tesla-model-y-batteries-byd-versus-catl/amp/ https://insideevs.com/news/668659/tesla-model-y-batteries-by...
- tooltalk 3y ago
  With the pack level density of ~140Wh/kg. CATL is Tesla's primary LFP supplier -- BYD was added earlier this year. The key sellig point here is the cost.

baybal2 3y ago

Preemptively posting what is people's biggest confusion: Battery cell energy density is not the same as the whole battery pack energy density. Western battery cell manufacturers chased the specific energy density figure, and in the process they decided to save weight on the casing, and electrodes as much as possible, resulting in very fragile battery cells. To avoid 18650 cells being crushed, you will need a lot of structural reinforcements added to the battery pack, consuming weight. Even with all of that, tiny, individually 18650 cells waste a lot of weight on the cell casing, on things like welds, terminals, relief valves, thermal interface material etc. Bigger cells invariably have better casing to active material ratio, but the casing mass is still "useless. Blade battery reverses all of above, and intentionally uses very strong, and thermally conductive case, to make the casing weight to contribute to battery pack mechanical strength. LFP cathode feels very well at high temperatures, and has very high resistance to mechanical expansion during charge. This allows to make LFP cells much bigger than cells with other chemistries, and removes the need for liquid cooling system inside the battery pack, greatly saving weight.

doubloon 3y ago

alot more detail here https://www.sae.org/news/2021/10/byds-blade-runner https://www.sae.org/news/2021/10/byds-blade-runner would love to be corrected here but if i understand they basically did away with the idea of "modules of cells" and just have the entire pack made of hundreds of cells directly attached to the bus. which ironically is more like the Prius battery (28 'prisms') than the Tesla battery (cylndrical). also seems to me like, they maybe dont have to flood the entire thing with disgusting pink foam, maybe you could have a halfway chance of replacing a single cell if it went bad.

ryzvonusef 3y ago

https://twitter.com/jimfarley98/status/1732584621890482514 https://twitter.com/jimfarley98/status/1732584621890482514 > They weren't joking. We received the document today, dated Dec. 5th. Thanks, @ElonMusk. Great for the industry!

m463 3y ago

Offering awards for things is kind of self-serving for a publication. Bet it drives up click rates. I remember reading something once, where famous people should carefully vet who they accept awards from. An award might just be a sneak way of getting some relevant person to speak at an event for free or a nominal cost.