[HN Gopher] Led by Tesla, EVs drive chip industry's shift beyond...
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Led by Tesla, EVs drive chip industry's shift beyond silicon
Author : Corrado
Score : 160 points
Date : 2021-09-06 10:01 UTC (12 hours ago)
(HTM) web link (asia.nikkei.com)
(TXT) w3m dump (asia.nikkei.com)
| dreamcompiler wrote:
| Why is SiC a good thing?
|
| 1. It has a higher bandgap energy than silicon, which means it
| can tolerate more heat without breaking down. It also means the
| junctions can be physically smaller.
|
| 2. Smaller junctions mean the transistors can switch faster,
| which means less time spent in the linear region, which means
| they generate less waste heat than silicon transistors.
|
| 3. SiC also has lower ON resistance, which means less waste heat
| still.
|
| 4. SiC _conducts_ heat better than silicon, so removing its
| [lesser] waste heat is easier and requires a smaller heat sink
| apparatus.
|
| All of this makes SiC a fantastic technology for power
| electronics. (It's less important for signal electronics, but
| even signal electronics waste small amounts of power so reducing
| that further is still relevant.)
|
| For EVs, SiC inverters mean less mass for an EV to carry around.
| Less mass _per se_ doesn 't matter as much as you might think for
| an EV because with regenerative braking you get back some of your
| acceleration energy when you decelerate. However, air resistance
| matters _enormously_ in an EV because you can 't get back the
| energy you lost pushing the car through the air. And "less mass"
| also means "smaller" and "smaller" means "more opportunities to
| make the car aerodynamically efficient."
| sonium wrote:
| Thank you for answering everything I ever wondered about SiC.
| Are there any other semiconductors that would be even better
| than SiC in all four points?
| dreamcompiler wrote:
| Diamond is even better in terms of bandgap and thermal
| conductivity (one way jewelers verify a diamond is real is by
| checking to see if the gem has ridiculously high thermal
| conductivity). But diamond semiconductors are much too
| expensive ATM.
|
| Gallium Nitride is the closest competitor to SiC now; it's
| better than SiC for high frequency applications but worse for
| high temperature applications and GaN is somewhat harder to
| manufacture. But that's changing rapidly.
|
| https://www.arrow.com/en/research-and-
| events/articles/silico...
| Corrado wrote:
| I didn't even think about non-silicon based chips being viable,
| let alone more efficient. The article mentions that SiC (Silicon
| Carbide) chips can be 50% more efficient. Diamond based chips can
| reduce energy loss by one-50,000th of that of Silicon chips.
|
| If we can get these chips manufactured at a reasonable cost it
| would really help EVs get longer range. And it might even give us
| multi-day use out of our smart devices (phones, watches, etc.)
| Cthulhu_ wrote:
| > And it might even give us multi-day use out of our smart
| devices (phones, watches, etc.)
|
| Not going to happen, they'll just find a way to use more power
| instead. You probably noticed that for years now, phones and
| the like have had a fixed battery lifetime of about a day of
| medium use, even though battery and chip technologies have
| improved. I'll admit that in terms of efficiency - performance
| per watt - things have increased, but the goal of the phone
| manufacturers is not to make things last longer, it's to
| min/max and find a balance between battery life and power.
|
| With current day technology you can easily make a phone that
| lasts for a month on a single charge, but it'd be bulky
| compared to what you can do with it.
| SuoDuanDao wrote:
| Once we all own nothing and are happy though, perhaps it will
| be in the phone company's interest to make their phones last
| longer so they can get more rental income off one asset.
| Corrado wrote:
| Yes, you're probably right. For proof we just need to look at
| RAM & CPU requirements for most software. As both of those
| components increased, the software grew to consume them.
| _sigh_ one can wish, can 't one?
| Traster wrote:
| As far as I understand it, these SiC chips are things like
| discrete MOSFETs designed to work at hundreds of volts and
| handle huge power running through them. I think the likelihood
| of this scaling down to millivolts is quite unlikely. The more
| likely applications for this are power stations and hooked up
| to solar power plants rather than in your iPhone I would
| expect.
| pwr-electronics wrote:
| You're correct that SiC is for medium to high voltage. But
| there's also GaN, which is for low to medium voltage, and
| already works in the millivolt range. Both GaN and SiC will
| have wider ranges in the future as the technology continues
| to improve.
| xondono wrote:
| SiC is not a good fit for anything under ~100-200V, it's just
| not what it is designed for.
|
| GaN makes more sense for consumer electronics, that's why it's
| popping up in a lot of devices, even if prices right now are
| too "high end" for most users.
|
| As for phones, watches, etc..:
|
| 1- These technologies won't be as dense as standard silicon for
| quite some time (if ever.
|
| 2- We've had big swings in both efficiency and battery capacity
| several times already, but it works in the same way internet
| speed works. Power-hungry features grow with increased
| efficiency in the same way websites grow in size with increased
| internet bandwidth.
| DoingIsLearning wrote:
| Silicon Carbide is extensively used in Power Electronics. It's
| just that there is a very small group of people that are having
| to deal with kilovolts on a daily basis, so I suppose it is not
| perhaps widely known.
| dtgriscom wrote:
| For some strange reason, my high school had a subscription to
| the EPRI journal [1]. For this budding nerd, reading about
| SCRs the size of hockey pucks, with optical fiber triggering,
| was quite entertaining.
|
| [1]: https://eprijournal.com/
| u320 wrote:
| All EVs are already highly efficient, any further increases is
| going to be extremely marginal.
| phkahler wrote:
| EVs tend to be efficient at high power. They can be 94-98
| percent efficient at 100kW but normal driving is something
| like 4kW at 45mph.
|
| If you reduce loads by 40 to 50 watts, you can gain a mile of
| range. With inverter losses in the 1-2 kilowatt range at high
| power there is room for improvement.
| sensitive-ears wrote:
| There is still plenty to be gained from squeezing that last
| 1% out. Tesla is probably cell limited right now, so if your
| car is 1pct more efficient you can pull less cells in it and
| mthen make 1pct more vehicles.
| li2uR3ce wrote:
| > And it might even give us multi-day use out of our smart
| devices
|
| I don't think you understand how software development works. Q:
| How much hardware do you need? A: How much you got?
|
| The latest generation only gets the battery longevity because
| software developers still have to support the previous
| generation. As soon as enough e-waste happens, the gains
| disappear.
|
| I might be a cynic but there sure seems to be a lot of
| empirical data to support my disorder.
| FartyMcFarter wrote:
| > If we can get these chips manufactured at a reasonable cost
| it would really help EVs get longer range.
|
| How much longer though?
|
| The motors that move the wheels consume way more energy than
| the microchips on board the car. Even when a car is standing
| still, the AC or the heating system are also quite energy-
| hungry compared to a few CPUs.
| pwagland wrote:
| That's certainly true, however the cooling required for the
| microchips also typically takes a lot of energy, as well as
| the microchips themselves. Reducing the energy usage, reduces
| the heat output, and thus also the cooling requirements.
| bad_alloc wrote:
| Yeah but in most EVs you need to transform the battery DC
| current to AC for the motor.
| ricardobeat wrote:
| I was under the impression the Model 3 uses permanent
| magnet DC motors, with the increased efficiency accounting
| for some of the range gains.
| elihu wrote:
| I think Tesla has been migrating from induction motors to
| permanent magnet motors (which usually have higher
| efficiency and produce less heat), but they all run off
| of 3-phase AC from the inverter.
|
| Sometimes the inverter/motor combination is referred to
| as a brushless DC motor because it takes DC as input
| before converting it to AC for the motor to use.
| vardump wrote:
| No electric motors are really DC driven. They do differ
| how the AC is derived, though, mechanically or
| electrically.
| tzs wrote:
| I've got an idea for a DC electric motor that has no
| apparent AC. Can anyone spot any hidden AC here?
|
| Take a disk on a shaft. Use a ratcheting mechanism on the
| shaft so that it can only rotate in one direction. Attach
| permanent magnets around the rim of the disk.
|
| Attach more permanent magnets to bimetallic strips
| positioned outside the rim of the disk. Near each
| bimetallic strip place a resistor.
|
| The angular spacing of the bimetallic strips and magnets
| around the outside of the rim should not be that same as
| that of the magnets on the rim.
|
| Turn the disk by moving one or more of the outer magnets
| closer to the rim to create asymmetrical torque on the
| disk. You move the outer magnets by using the resistors
| to heat the their bimetallic strips. You move an out
| magnet back to its original position by letting it cool
| back down.
| detaro wrote:
| The voltage driving the resistors? _Just_ terribly slow,
| matching the terribly slow speed of the motor.
| tzs wrote:
| That would be variable DC, not AC.
| MauranKilom wrote:
| Why would you use bimetallic strips instead of, say, a
| solenoid? The whole point of the discussion is to avoid
| thermal losses...
| tzs wrote:
| The comment I was replying to said DC motors actually use
| AC internally. My comment was an attempt to design a DC
| motor that definitely uses no AC.
|
| Solenoids have an inductor with a changing magnetic field
| that stores energy and eventually gives it back. I want
| to avoid the possibility that that changing magnetic
| field will induce a current somewhere that is in the
| opposite direction of the normal current in that place
| thereby producing AC.
|
| By just using the DC input to make heat, there is no
| chance of inadvertently getting AC.
| formerly_proven wrote:
| > You move the outer magnets by using the resistors to
| heat the their bimetallic strips. You move an out magnet
| back to its original position by letting it cool back
| down.
|
| You are switching the resistors on and off with a pulse
| pattern that will look a whole lot like you're driving a
| stepper motor. That's what we call AC.
|
| DC means that the voltage stays constant over time. AC
| means it changes. Switching DC on and off creates AC.
| p1mrx wrote:
| That sounds like a
| https://en.wikipedia.org/wiki/Stepper_motor with extra
| steps.
|
| You could argue that a stepper motor is also just pulsed
| DC, though it starts looking more like AC as you increase
| the drive efficiency.
| pitched wrote:
| When the resistors are heating, there must be more power
| going through them then when they're cooling, right?,
| fennecfoxen wrote:
| To say a word about the physics: The fundamental force at
| play is the electromagnetic force. If you run a current
| in a coil in the magnetic field, it will rotate so that
| the coil's field comes into alignment with the outer
| field.
|
| Once it's there it is happy to stay. You've got to change
| something to get the motor running continuously. AC is
| quite clever about it because it just changes the field
| electrically and this is much more reliable than changing
| it with moving parts.
| adrr wrote:
| Model 3 uses two types of motors in the dual motor model
| and performance model. AC in the front and DC in the
| rear.
| elihu wrote:
| I think you're confusing induction versus synchronous
| reluctance permanent magnet motors with AC versus DC.
|
| The motors Tesla uses are all AC, but you could also call
| them DC if you're referring to the whole motor/inverter
| assembly, which inputs DC from the battery.
|
| DC motors aren't used much in EVs because the brushes
| require periodic maintenance and doing regenerative
| braking or running in reverse are both rather difficult
| whereas with a motor that runs off of 3-phase power,
| those features can be implemented in the software of the
| motor controller. They tend to be rather low efficiency,
| too. That said, there are some really powerful and cheap
| series wound DC motors that have been used to great
| effect in vehicles like the White Zombie.
| _fizz_buzz_ wrote:
| The power electronics in an electric drive train also have
| transistors. That's where you can make real efficiency gains
| in an electric car. Not in some microcontrollers.
| eutectic wrote:
| Presumably you mean to rather than by?
| ricardobeat wrote:
| https://archive.is/pRgwN
| hristov wrote:
| Good article, but very Japanese centered. This of course is
| understandable, as it is coming from Nikkei.
|
| There has been a lot of news about how the US is giving up
| leadership in semiconductors to Asia, but the US has actually
| been holding our own in Silicon Carbide. A US company called
| Cree, through their division Wolfspeed is the leader in
| manufacturing silicon carbide wafers. AFAIK, they are still
| making the most wafers in the world.
|
| There is another little known US company, ON semiconductor, that
| is arguably the leader in auto grade silicon carbide chips. They
| were not the first to make the sic mosfet, but they were the
| first to make sic mosfets that are qualified for use in cars. On
| Semi had acquired the legendary Fairchild semiconductor which had
| a lot of expertise in high voltage high power applications for
| auto and industrial. This probably helped commercialize silicon
| carbide.
|
| This is arguable of course, but ON semiconductor insist that they
| make the highest performance automobile grade SiC chips on the
| market.
|
| To see how fast this technology is moving, you can watch this
| video [1] where sandy munro needs a helper to wrestle with the
| ford mach-e inverter on a table. And then you can see this video
| [2] where the CEO of ON semi, holds two inverters for a car and
| an suv in each hand effortlessly.
|
| [1] - https://www.youtube.com/watch?v=mHVV52lPyIs&t=1086s, see
| around minute 15.
|
| [2] https://www.youtube.com/watch?v=jfq0kDzyPZY - see about
| minute 46.
| cptskippy wrote:
| > To see how fast this technology is moving, you can watch this
| video [1] where sandy munro needs a helper to wrestle with the
| ford mach-e inverter on a table.
|
| My take away from watching that clip wasn't him being confused
| with the function of the inverter but rather being puzzled by
| how every step of the assembly eschews the principles of Henry
| Ford and even the rules he said he wrote while at Ford.
|
| Maybe you linked to the wrong time?
| CSSer wrote:
| I am far from a subject matter expert on this, but I have been
| doing my best to read up on this lately. It seems like we're
| globally diverging on fabrication expertise at a process level
| i.e. nanometer scale [0]. The bulk of leading edge chip
| manufacturing (currently around 7nm or below) seems to indeed
| be slipping away to Southeast Asia, but as you said the U.S. is
| holding their own at larger process levels (Cree is mentioned
| in the article as well) and still producing at a volume that
| may be surprising to many doomsayers. It's worth noting at this
| point that, according to the article I linked below, it is
| estimated that five larger process chips are required for every
| leading process chip produced. So this doesn't seem to entirely
| be an accident on the part of U.S. companies. Sure, some
| companies like Intel have simply failed to innovate in the past
| few years, but others seem to have made a calculated decision
| to avoid massive R&D expenditures that may or may not pay off
| as we begin to approach the limits of Moore's law. The reality
| is that leading edge chip fabs are extraordinarily expensive. I
| read a podcast transcript recently with a prominent professor
| who is an expert in this field [1]. He mentioned that he did
| some consulting for the U.S. Govt., and when they asked him for
| his estimate for how much it would cost in subsidies to catch
| up with or outpace the rest of the world in fabs his response
| made the guy who asked the question practically fall out of his
| chair. Have we reached a point where quantity (at an average
| level of quality) is now more important than having the fastest
| and the smallest IP?
|
| [0]: https://semiengineering.com/can-the-u-s-regain-its-edge-
| in-c... [1]: https://www.theverge.com/2021/8/31/22648372/willy-
| shih-chip-...
| cma wrote:
| EUV LLC was heavily funded by DARPA and US industry in the
| 90s and is why we are able to have export restrictions on
| (European) ASML machines used by TSMC for the latest EUV
| nodes.
| seanmcdirmid wrote:
| > seems to indeed be slipping away to Southeast Asia
|
| Do you mean east Asia? Southeast Asia still doesn't have much
| fab capacity, and most of what it has isn't very
| sophisticated, unless I'm missing something?
| RC_ITR wrote:
| I think this is just some people's reflexive notion that
| 'China + sometimes Japan' = East Asia & 'Rest of Asia' =
| southeast Asia.
|
| It was mostly started by China companies like Alibaba
| treating any international expansion as 'Southeast Asia,'
| since they did it via HK or SG offices.
| chrischen wrote:
| The leading fabs are in Taiwan and South Korea.
| CSSer wrote:
| Yes, sorry. East Asia is what I meant. To be completely
| honest, I'm not sure if I read SE Asia somewhere or if I've
| always just thought of Taiwan as SE Asia for some reason.
| Mercator projections, maybe? Anyway, today I learned Taiwan
| is in East Asia, north of Southeast Asia.
| ksec wrote:
| >There is another little known US company, ON semiconductor,
|
| I chuckled. Only on a Software developer focused forum would ON
| being called a little known US company. They are really well
| respected in semiconductor industry. If I remember correctly,
| ON along with Freescale came from Motorola.
| neltnerb wrote:
| Yup, to me they're known just a bit less than TI and Analog
| Devices (now that Atmel and ST Micro are gone) and more than
| Microchip or ST because they serve so, so many high power
| applications.
|
| I just think those high power applications are invisible,
| like tens of percent reductions in the power used in an
| application. You can see them if you measure closely but not
| if you're casually working with it.
| Koraza wrote:
| Wow. EVs future looks exciting!
| imglorp wrote:
| I think the comments might be missing the bigger picture. It
| might be a few percent improvement dissipation or range: minimal
| impact to you, say 2 watts per car.
|
| But if they are shipping 800k cars per year that's 1.6 MW off the
| global power consumption for those new cars.
| qayxc wrote:
| You're using the wrong units. 1.6MW global power consumption
| has no meaning on its own. 1.6MW is the power that two sports
| cars can generate.
|
| Power consumption (e.g. energy) requires time, so 2W per car at
| 2 hours of daily use would be 4Wh per car per day or about
| 1460Wh per year per car or 1168MWh for 800k cars.
|
| That's the electricity consumption of ~106 average US
| households [0].
|
| I think that gives a much better picture of the amount of
| energy you're talking here.
|
| [0] https://www.eia.gov/tools/faqs/faq.php?id=97&t=3
| wallacoloo wrote:
| To an outsider, "4Wh/day" could also be expressed as "167 mW
| (amortized)". Wh/day is an idiom. I think it's strange to
| claim that it's the only "right" way of expressing power
| consumption. For a good many people outside the field, the
| first thing we do when we see such a figure is convert it
| back to its SI units so that we can do our calculations
| within the system that we're more familiar with (and
| something like 90% of the world uses SI).
| qayxc wrote:
| First of all I was talking about power consumption, which
| is never expressed in MW or kW.
|
| Secondly, mW is also power, not electricity consumption.
| 4Wh is power consumption (or electricity use if you will).
| The "per day"-part was just referring to the _duration_ ,
| hence the use of a different unit. I could just as well
| have used Joules and skip the "day"-part entirely to
| confuse the reader as to how I arrived at the final figure.
|
| Edit: just to make this even clearer - do the dimensional
| analysis yourself and see why I used Wh/day. Or to put it
| differently: what do think is the answer to the question
| "say a car saves 4Wh of electricity every day. How much
| electricity does the car save in a year?"
|
| Correct me if I'm wrong, but I'd say it saves 4Wh/d*365d =
| 4*365 Wh/d*d = 4*365 _Wh_ (or 5.256 MJ if you insist).
|
| > the first thing we do when we see such a figure is
| convert it back to its SI units so that we can do our
| calculations within the system that we're more familiar
| with
|
| I bet my firstborn that the vast majority of the population
| will not do that and are not familiar at all with the
| actual meaning of the figure.
|
| Had I converted the whole shebang into Joules instead and
| expressed the total energy savings as 5.256 Terajoule I can
| guarantee that outside the odd physics major no one would
| be familiar with what kind of energy use we're talking
| about.
|
| Look at your electricity bill and tell me what it unit it
| uses.
| josephcsible wrote:
| > 1.6MW is the power that two sports cars can generate
|
| If by "sports cars" you mean Bugatti Veyrons, then sure. For
| more "normal" sports cars, you'd need a bit more than 2.
| qayxc wrote:
| Only if you completely ignore the tune-up and car modding
| scene.
|
| On the BMW side we have the G-Power G6M V10 Hurricane CS
| (based on the M6 Coupe), for Mercedes there's the Mansory
| Black Edition (based on the Mercedes S-class/S 63 AMG),
| Underground Racing uses the Audi R8 V10 TT for its 1500 HP
| machine, the Porsche 911 has a 9ff F 97 A-Max incarnation
| with about 1400HP and the 9ff GT9 V-Max.
|
| The 9ff GTurbo comes in at a mere 1200HP, based on the 911
| GT3 and there's more.
|
| So no, in the car enthusiast scene even 1MW is is not
| uncommon. And that's not using Lamborghinis or Bugattis.
| You'd be surprised how many street legal modded M3s,
| S-class and 911 have 800kW or more max power (at least in
| Europe).
|
| Edit: shame on me - I forgot the Tesla Model S Plaid. Those
| have straight up 750kW electric power trains, too.
| mrpopo wrote:
| No point gaining a few points in efficiency if the cars
| themselves keep getting bigger and bulkier.
| davedx wrote:
| There's a huge, big incentive to increase Wh/kg though which
| will reduce EV mass significantly. Tesla's 4680's will make a
| decent step forwards there.
| Cthulhu_ wrote:
| It's the irony of the push for more efficiency. In theory you
| could have the equivalent of a 90's PC now with a fraction of
| the power consumption, but in practice any gain is used to
| create more powerful chips and do more calculations. There's a
| saying that was more about financial budgets, but tl;dr
| expenses will fill up the budget.
|
| In my country there's irony as well. On the one side, power
| companies and the government invest a lot in green power
| production, offshore windmill farms and solar farms and the
| like. But at the same time, companies like Microsoft and Google
| come in and have datacenters built that use up all the energy
| that those 'green' alternatives produce. We would've been
| carbon neutral years ago if it wasn't for the increase in power
| consumption that follows production.
| gruez wrote:
| >We would've been carbon neutral years ago if it wasn't for
| the increase in power consumption that follows production.
|
| What country is this? US power consumption is flat or
| trending down:
| https://www.eia.gov/energyexplained/electricity/use-of-
| elect.... I'd imagine that's the same for most developed
| countries, so your thesis would be wrong.
| bildung wrote:
| That's only because production has been moved to developing
| countries. Calculating consumption-based energy use (which
| includes energy "embodied" in things produced elsewhere,
| but consumed in the US), things look less great. See
| https://eeb.org/library/decoupling-debunked/ p. 21 (in the
| context of decoupling of material use and GDP growth)
| marcosdumay wrote:
| It's another face of the same effect that causes the Jevon's
| paradox. At _some point_ it stops and further efficiency
| leads to less consumption, but there 's nothing that says
| that point is achievable.
| colechristensen wrote:
| With computers it did. Everybody had a PC that used
| hundreds of watts, now much of that is running on 4 watt
| phones or 80 watt laptops.
| mrpopo wrote:
| The main power consumption of electronics is the embodied
| energy (energy used to build the device), and the number
| of devices per person has kept increasing worldwide (24
| per household in the US! https://www.forbes.com/sites/tjm
| ccue/2013/01/02/24-electroni...)
| marcosdumay wrote:
| I bet the sum of those 24 devices still uses less energy
| than a Pentium IV and a CRT monitor.
|
| IoT will take off at some point, and we may see a period
| when the many dozens of devices it needs use more power
| than an early 00's PC, but those will be optimized too
| (if IoT isn't delayed enough that they are born
| optimized).
|
| I imagine there is enough demand for computing to
| eventually go over the 00's level, but I can't imagine
| its form.
| mrpopo wrote:
| Again, in a life cycle analysis, energy use from
| utilisation is dwarfed by energy used during production.
| With IoT the number of chips will keep increasing and
| that's what determines the total energy (carbon)
| footprint, which is not the same as your electricity
| bill.
| colechristensen wrote:
| You have a point to a degree but a big PC+CRT is going to
| have those same costs and has a lot more mass to require
| energy during production, even compared to several mobile
| devices.
| oh_sigh wrote:
| Can't exactly conflate energy with carbon though, because
| manufacturers will use green energy at various stages of
| the manufacturing process.
|
| Just to put numbers on this, according to this article
| from 2014[0], an iPhone has an embodied energy of 278
| kwh, which is about 10 days of energy usage for the
| average American household.
|
| [0] https://www.theatlantic.com/technology/archive/2014/1
| 0/the-e...
| mrpopo wrote:
| The carbon neutral claim is a huge stretch, but otherwise
| yes.
| NotSammyHagar wrote:
| My cell phone is a perfect example of what you are saying we
| should have had. I can connect up a keyboard and mouse and
| monitor. The lcd monitor also uses vastly less power.
| thatfrenchguy wrote:
| For electric cars though, you make more money as a carmaker if
| their batteries are smaller, which happens when your
| consumption is lower, so it encourages slicker designs, unlike
| ICE cars where somehow Americans still think 20mpg is
| acceptable in 2021, and the carmaker makes as much money or
| more selling you a 20 or a 50mpg car.
| tenpies wrote:
| Unfortunately, and also "Led by Tesla" - the EV metrics that
| people have been trained to look for are now: range, 0-60
| times, and such.
|
| Things like weight, battery capacity, or chemistry - all
| which have the largest impact on emissions - are ignored. In
| fact, judging by the chemistries that Tesla is now exporting
| from China, there will be a very serious effort to hide
| battery chemistry as much as possible.
| njarboe wrote:
| The biggest emission reduction is when a person switches
| from using an ICE car to a EV car. Getting the price of a
| new EV car to be below a similar ICE car will cause that to
| happen very quickly. These new battery chemistries using
| iron instead of nickel are a key to reducing price and will
| lead to much quicker overall emission reductions. Also
| price is a close proxy for total energy. A ton of iron
| (~$200 a ton) surely takes a lot less energy to produce
| than a ton of nickel (~$20,000 a ton). I have no idea how
| much less but I would guess somewhere between 10 and 50
| times less.
| WhompingWindows wrote:
| The cars getting bigger and bulkier are ICE SUVs and trucks
| largely, things like Cadillacs, Jeeps, fully loaded trucks
| being used as commuters, etc. Tesla actually started larger
| with S/X then moved downwards in size/cost towards 3/Y. Most of
| the other makers have moderate sized EVs, like Priuses, Volts,
| Bolts, Leafs (leaves?), they're all modestly sized.
| ac29 wrote:
| Passenger cars have also gotten significantly larger since
| the 1980s/90s. I think its mostly to do with enhanced safety
| features.
| fy20 wrote:
| EVs are still significantly heavier than the ICE equivalent
| though, compare models from European manufacturers that sell
| the same body in EV or ICE versions. The EV version is
| typically a few hundred kilogram heavier, or even more if you
| get a bigger battery.
| baybal2 wrote:
| There is not much they can show to really lead besides switching
| to superior switches.
|
| I admit Tesla's inverter design is very conservative, but it's
| very thorough engineering.
| londons_explore wrote:
| I'm really surprised you don't see the inverter and the motors
| closer coupled in Tesla's designs.
|
| For example, by having MOSFETs spliced into the wire wound onto
| the stator. That minimises wire length (and therefore
| resistance). The heavy motor windings are a great heatsink for
| brief acceleration, and both will need liquid cooling for
| prolonged 100 mph driving up a hill.
| baybal2 wrote:
| Almost all high power switches are made to be soldered
| directly to cables.
| baybal2 wrote:
| @madengr it seems you were secretly banned (shadowbanned)
|
| https://ibb.co/NK6Yhj5
| madengr wrote:
| The article mentions GaN not widely used because it is
| integrated with Si. Cree's process is GaN on SiC, so you'd get
| better heat dissipation than in Si, but it costs more. There
| are also done processes integrating a diamond heat spreader
| under the GaN channel.
| quanto wrote:
| The article doesn't pass the smell test for me.
|
| Claim 1. Smaller SiC inverters enabled Tesla to implement sports-
| car-like streamlined design.
|
| Traditional Si inverters are not that big. Certainly not big
| enough to single-handedly change the car design [1]
|
| Claim 2. Hyundai will use SiC chips to increase its typical EV
| range by 5%.
|
| The article claims that SiC will reduce wasted energy by half (or
| more). If we go by this figure, Hyundai's EVs need to waste 10%
| of its energy on Si chips. This seems quite high to me. No doubt
| there are losses in the motor, power electronics, and battery,
| but losing 10% of the EV's total energy on Si based _chips_ seems
| incredibly inefficient to start with.
|
| [1] https://www.youtube.com/watch?v=mHVV52lPyIs&t=909s
| tuatoru wrote:
| > If we go by this figure, Hyundai's EVs need to waste 10% of
| its energy on Si chips.
|
| Most of it is not lost in the silicon, but in the interconnects
| (wiring and connectors) and motor(s).
|
| SiC is better (more robust) than Si with high voltage, high
| current, and/or high temperature. Specifically, kilovolt-level,
| kiloamp-level, and temperatures above 150 celsius.
|
| If you double your battery voltage from 400V (current standard)
| to 800V, you halve your resistive losses in the "wires" for the
| same electrical power demanded. Silicon MOSFETS that can
| withstand a kilovolt and a kiloamp are very big and very
| expensive.
|
| You get more power delivered for the same power leaving the
| battery.
|
| Size: SiC's very high thermal conductivity means less of a
| margin of safety for secondary breakdown. SiC tolerates higher
| current density (amps/square mm) than Si, so smaller devices
| are possible, saving mass.
|
| Its temperature stability allows it to be sintered to the
| package heatsink--further improving heat removal. Tolerance for
| high temperatures means you need less mass and volume for heat
| dissipation structures.
|
| Other efficiencies: With very high currents (kiloamp) and
| medium frequency switching, SiC IGBTs provide more benefits,
| because rather than being directly proportional to current as
| with MOSFETs, losses are proportional to the log of current.
|
| Alternatively, doubling the battery voltage again to 1.5kV (and
| so halving the currents) might allow Hyundai to use more
| aluminium for the "wires", with a cost saving over copper.
| formerly_proven wrote:
| Resistive losses are proportional to current squared, not
| linear.
| MertsA wrote:
| >Alternatively, doubling the battery voltage again to 1.5kV
| (and so halving the currents) might allow Hyundai to use more
| aluminium for the "wires", with a cost saving over copper.
|
| This seems dubious, you're not going to be able to use
| aluminum for motor windings which is where the bulk of the
| copper in an EV is going to be. As for conductors between the
| battery, HV auxiliary devices, inverter, motor, charger, etc
| they could already use aluminum, it's not like they're space
| constrained on the gauge of cable between components.
| Aluminum is already more mass efficient than copper, you
| might need a thicker gauge to match the same resistance but
| that thicker aluminum is still lighter than copper and way
| cheaper. The problems with aluminum are oxidation and
| brittleness. Maybe eventually auto manufacturers will shift
| more towards aluminum bus bars between components with no
| relative movement but I don't see a big link here between
| ampacity and the choice between copper and aluminum.
| tardismechanic wrote:
| > but electric vehicles are helping chip away at its dominance in
| the pursuit of energy efficiency.
|
| I suspect the authors did not intend that pun ("chip away", get
| it ;-) )
|
| Is there a name for such unintentional puns?
| xyzzy21 wrote:
| So wrong!
|
| Non-silicon is 10x-100x more expensive and 10x-100x less fit for
| most applications.
|
| Non-silicon (aka compound semiconductors) are only 1% of all
| semiconductor revenue and volume. Switching from majority
| semiconductor to tiny minority semiconductor is NOT going to
| solve any supply problems!!
|
| SiC and GaN are STILL made on silicon and most of the circuitry
| is still silicon. Only the power transistors are using non-
| silicon.
|
| Mostly a nonsense article.
| tus89 wrote:
| Thanks God the beaches are running out of sand!
| Koiwai wrote:
| I'd like to point out this is not about increased range, for
| example, if the ECU already works at 95% efficiency, that's not a
| very high number for brushless ECU, just for example, so 5% of
| energy is wasted, if we can reduce that in half, the efficiency
| will only increase to 97.5%, that's a very small improvement on
| range. BUT, now the ECU only needs to dissipate half wasted heat,
| this could be a big net win.
|
| A more close to everyday life example would be chargers for
| notebooks, we now have smaller chargers thanks to GaN FETs, SiC
| is like GaN.
| engie wrote:
| This is the key observation - hitting breakpoints in efficiency
| that let us remove active cooling, silicon area or heatsinks
| reduce weight, cost & complexity.
| taneq wrote:
| Yep. High efficiency is also the key to the crazy high
| performance we see in high end EVs these days. Going from 96%
| to 98% drivetrain efficiency only gives you 2% more battery
| life but it doubles your power output.
| sudosysgen wrote:
| You mean ESC, not ECU.
|
| Generally cooling ESCs is not that big of an issue, just stick
| them in the same cooling system as the batteries.
| hwillis wrote:
| arguably the same thing. If you want to get pedantic, "ESC"
| refers to a specific subset of drive topologies that are all
| fairly lossy on the D axis, meaning the efficiency drops at
| low speeds or under heavy acceleration.
|
| "Drive controller" or "motor controller" are common terms,
| and while I have seen acronyms like DCU, nothing really
| sticks. MCU is already taken as an acronym, which doesn't
| help.
| sudosysgen wrote:
| ESC doesn't have any connection to efficiency as a function
| of load. All circuits will be less efficient as you output
| more amps, ie, at low speeds where the voltage is low but
| the power stays the same, or under heavy acceleration.
|
| Nowadays ESC simply refers to any circuit you attach to
| motor and provide with a target speed/torque/power. In
| common practice yeah ESC/drive controller/motor controller
| are used interchangeably.
|
| ECU is specifically something else. It's "Engine Control
| Unit". It refers to the controller for a combustion engine,
| not a motor.
| londons_explore wrote:
| This isn't quite right...
|
| In a car which can accelerate up to speed and brake again every
| 30 seconds while going through a city with a lot of stop lines,
| the efficiency of the power components really matters.
|
| If you loose 5% in the motors, 5% in the power electronics and
| 5% in the battery in each direction, then each accelerate-brake
| cycle is losing you ~30% of the energy you started with. At
| town speeds, friction and air resistance losses are tiny, so
| that 30% is probably actually most of the energy you are using!
|
| Add that to the fact that certain motor control techniques such
| as field weakening involve every Amp of real power that comes
| from the battery passing many times though the inverter, since
| there is a higher circulating current between inverter and
| motor coils.
| sudosysgen wrote:
| You're going to lose a lot more than 5% in the motor. You
| will also lose more to rolling resistance, various
| hystereses, etc...
|
| Even assuming 100% inverter efficiency you will lose at least
| 20% in the regen part of the cycle alone.
| londons_explore wrote:
| Motors can get well above 95% efficiency, even at a wide
| range of speeds and torques.
|
| Eg. See https://cdn.motor1.com/images/mgl/y83JG/s3/tesla-
| motor-effic...
| sudosysgen wrote:
| They can when they are being used to produce kinetic
| energy. Using a motor as a generator however has much
| lower efficiency.
| hwillis wrote:
| Absolute nonsense. Motors are do not care whether they
| are generating or consuming electrical power. It is a
| fundamental fact of induction that _rotation in the motor
| creates a reverse voltage_ - motors literally would not
| work if they did not have very similar efficiency as
| generators.
|
| The only differences between a motor and a generator in
| practice are cost optimizations and fixed-frequency
| optimizations. Industrial generators run at fixed speeds,
| unlike EV motors, so they can be built more cheaply. EV
| motors are not any less efficient when used to recapture
| power.
| oh_sigh wrote:
| You could say the same thing about how
| speakers/microphones are equivalent. But it should be
| clear that some of those devices are tuned for outputting
| sound vs inputting sound, or vice versa.
| sudosysgen wrote:
| That is true in theory. In practice, when using the motor
| as a generator, the operating conditions are different,
| and so are the efficiencies. The load side is also
| different, the motor controller will not act the same way
| as the inertia of the car.
|
| For example, even the simple inductance and resistance of
| the motor means that at the same speed and at the same
| load angle you will see a lower voltage at the poles of
| the motor when acting as a generator. When your motor has
| high efficiency, these differences can lead to a large
| absolute difference when running as a generator.
| Koiwai wrote:
| > If you loose 5% in the motors, 5% in the power electronics
| and 5% in the battery
|
| You realize SiC is not the savior for all your problems
| right?
|
| I'm not saying efficiency doesn't matter, I'm saying this is
| not gonna improve range significantly, there is a difference.
| marcosdumay wrote:
| The GP's point is that this is not about maximum range,
| it's about increasing range in city transit that is
| normally much smaller.
|
| Both gains seem relevant to me.
| sudosysgen wrote:
| EVs typically have more range in city transit than on the
| highway.
| ianai wrote:
| Totally! X^n with 0<X<1 quickly goes to zero as n increases.
| You get about 6 of those cycles if X=.9 before you lose 50%
| of what you started with initially.
| ndm000 wrote:
| Is there a market for SiC chips in cloud data centers? I'm
| unfamiliar with the space, but 50% efficiency gains (if costs can
| be kept comparable) could be a game changer.
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