[HN Gopher] Innovation of the Year: BYD Blade Battery
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Innovation of the Year: BYD Blade Battery
Author : hunglee2
Score : 96 points
Date : 2023-12-10 08:17 UTC (14 hours ago)
(HTM) web link (www.electrifying.com)
(TXT) w3m dump (www.electrifying.com)
| _Microft wrote:
| 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
| catchnear4321 wrote:
| 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 wrote:
| 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=mN 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 m 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 wrote:
| > 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=mN 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_ wrote:
| 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 wrote:
| 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 wrote:
| 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
|
| 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.
| KolenCh wrote:
| It depends on what kind of friction you're talking about
| too. Eg it is well known that for some fluid (air for
| example), the friction can be proportional to the speed
| instead, to a certain extend of course, and can be proved
| in an idealized situation.
| joosters wrote:
| 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 wrote:
| BYD actually started as a battery maker.
| DoesntMatter22 wrote:
| Only if you consider a hybrid to be an electric car. Tesla
| is still bigger on BEVs
| xbmcuser wrote:
| They are expected to get ahead of Tesla end of this year.
| DoesntMatter22 wrote:
| Most things I've seen say next year. Regardless, it's not
| a fact that they are the biggest yet.
| throwawaymaths wrote:
| 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 wrote:
| Wasn't there news recently that a big supplier started
| selling commercial sodium batteries?
|
| Found it https://northvolt.com/articles/northvolt-sodium-ion/
| conradev wrote:
| Better cell design and better chemistry both contribute to
| safety, and I think the Blade's primary innovation here is
| their cell design
| hedora wrote:
| 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 degC (86
| to 140 degF). 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 wrote:
| 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.
| ramesh31 wrote:
| >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.
| lnsru wrote:
| I share your opinion. Everything <60 kWh has no real
| winter range. 60 kWh battery brings me 150 miles in
| winter (Autobahn in Germany, not saving energy) since the
| regular battery shouldn't be charged to 100% and
| discharged bellow 10%. That's 2 days of commuting without
| charging for me.
| Tagbert wrote:
| I believe that is one of the benefit of the LFP chemistry
| that it is not harmed by sustained charges to 100%. That
| should help offset the range downside sometimes listed
| for LFP batteries.
| uxp100 wrote:
| However, IIRC it has other problems in cold weather. With
| charging, I think? I know I've seen reports that
| regenerative braking is essentially completely disabled
| while the LFP batteries are cold.
| jorvi wrote:
| > 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 degC (86 to 140
| degF). 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 degC (572 degF) 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.
| consumer451 wrote:
| > Lfp chemistry is not that innovative
|
| 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.
| ramesh31 wrote:
| >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
|
| Cell chemistry is just one part of the equation. Better
| (lighter) pack designs are equally important to increasing
| overall energy density, safety, and reliability.
| ggm wrote:
| 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 wrote:
| 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 wrote:
| 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 wrote:
| 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_pa
| cking
| doubloon wrote:
| 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 wrote:
| The problem is BYD's LFP battery energy density is only 150
| Wh/kg. Compared to 260 in something like a Tesla.
| reitzensteinm wrote:
| Are you saying Tesla's LFP is 260 Wh/kg, or are you comparing
| across chemistries?
| gridder wrote:
| the latter
| oittaa wrote:
| 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 wrote:
| 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 wrote:
| Tesla is already using BYD's blade batteries in the Model Y in
| Europe:
|
| https://insideevs.com/news/668659/tesla-model-y-batteries-by...
| tzs wrote:
| Tesla switched to LFP for the standard range model 3 and Y a
| year or so ago.
| olex wrote:
| Longer. My M3 RWD delivered in December 2022 has a third-gen
| LFP pack with 60 kWh capacity, in the years before they used
| first a 50 and then a 55 kWh packs before going to the
| current 60 kWh variant.
| thebruce87m wrote:
| One upside is that you can charge them to 100% daily, whereas
| NMC they recommend 80%.
| jauntywundrkind wrote:
| The lower energy density is a real factor, yes!
|
| But personally it just seems so worth it. LFP has far greater
| cycle count than Li-ion. That the battery is going to last 4x
| longer or more is a huge factor for me. The net-energy (across
| the usable battery lifetime)/$ is so much vastly better that
| I'm happy in most applications dealing with the weight.
| doubloon wrote:
| alot more detail here 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 wrote:
| 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 wrote:
| 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.
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