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SuperCap discussion (out of main)
- Thread starter Hock1
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Swampgator
Active Member
Karen says capacitors do not make sense in cars. I trust her skills on this issue. Maxwell aq for dry electrode tech only.
I trust Elon's skills more than Karen's. He is, according to Gali, very optimistic about ultra caps in electric cars.
Not an expert but I heard that the strength of ultra-capacitors is that their capacity does not deteriorate with repeated charges. Their disadvantage is that per unit of weight, they don't store as much electricity. I reckon the idea is that an ultra capacitor in an EV can take the brunt of the regenerative braking/accelerations, and therefore save the main battery in the long term.
I think the point is that the tech could perhaps increase the number of miles you can get out of a lithium ion battery. Perhaps its part of the path to the million mile lifespan of a Tesla vehicle without a battery replacement.
This is obviously the idea. Karen didn't think it provided enough buffer to make sense given how much the ultracaps actually cost. And... she's probably right, but the Roadster is a "more money than sense" car anyway, so....
There's actually no contradiction. IIRC -
EM: ultra cap eventually when it has enough energu density it will be a better solution than chemical battery.
Karen: ultra cap at today's energy density do not make sense in any price to be used in a car, because you can add chemical battery of the same weight to have more discharging and charging capability than can be provided by the best ultra cap today.
OT
Neither is the long-term solution.
Eventually, we should use controlled magnetic potential storage, because magnetic potential storage has 100 times the possible energy density of electric potential storage. (There were articles on the lab tests for this several years ago; this is known). Unfortunately, the mathematical method for controlling magnetic potential storage (which was developed by people I know) has never made it to lab stage. And may never make it to lab stage, since the people who developed it got tired of running startups and fighting with vulture capitalists, said "to hell with humanity", and are essentially having fun rather than developing it.
Such is life.
Neither is the long-term solution.
Eventually, we should use controlled magnetic potential storage, because magnetic potential storage has 100 times the possible energy density of electric potential storage. (There were articles on the lab tests for this several years ago; this is known). Unfortunately, the mathematical method for controlling magnetic potential storage (which was developed by people I know) has never made it to lab stage. And may never make it to lab stage, since the people who developed it got tired of running startups and fighting with vulture capitalists, said "to hell with humanity", and are essentially having fun rather than developing it.
Such is life.
EVNow
Well-Known Member
Um, where are you getting this? Tesla does not report disengagement rates.
Also, disengagement rates are plenty easy to rig. One, you only have to report safety-related disengagements, so if the car is going to miss a turn because it can't change lanes, or whatnot... you just let it rather than disengaging. And two, if there's anywhere that you know the car struggles with, you just exclude that from your geofence until you've gotten good at it in your simulator of that location.
Artful Dodger
"Neko no me"
Gali's badly out of date. Elon was planning to study ultracaps for his PhD thesis BEFORE he quit to found Zip2. That's like what, 20 years ago?
Is it possible that capacitor...
Charging characteristics can improve charging time.
Differentiate Tesla products from competition and help margins by increasing the value of the Performance versions.
This would be a way to scale the technology from low volume to higher volume without disrupting 2170 production horizons.
Mod: I think there was already a thread for this but didn't have time to dig it up. --ggr.
omgwtfbyobbq
Active Member
My sense is that Tesla bought Maxwell for their dry electrode tech and for their capacitor line.
Improvements to the Tesla packs/Panasonic cell manufacturing via integrating Maxwell's electrolyte tech into existing manufacturing are clearly a winner for Tesla if they can pull them off.
At the same time, Maxwell's ultracaps may also be very beneficial for Tesla, especially if they are moving into markets where they can't use Panasonic as their supplier for some reason and have no choice but to buy commodity cells from someone else. In this case, integrating ultracaps into the power electronics of their cars could significantly improve regen across the board, battery pack lifespan, and cold weather power output.
As others have said, they can also use them to boost performance of their high end options. Integrating them isn't very easy because caps have voltage that's linear to the amount of energy they're holding. However, Tesla builds all their own power electronics, and can likely integrate them into existing functionality (boost/buck converters) in way that allows them to make much better use of them than they could if they had to add them as a discrete/external cap bank.
Improvements to the Tesla packs/Panasonic cell manufacturing via integrating Maxwell's electrolyte tech into existing manufacturing are clearly a winner for Tesla if they can pull them off.
At the same time, Maxwell's ultracaps may also be very beneficial for Tesla, especially if they are moving into markets where they can't use Panasonic as their supplier for some reason and have no choice but to buy commodity cells from someone else. In this case, integrating ultracaps into the power electronics of their cars could significantly improve regen across the board, battery pack lifespan, and cold weather power output.
As others have said, they can also use them to boost performance of their high end options. Integrating them isn't very easy because caps have voltage that's linear to the amount of energy they're holding. However, Tesla builds all their own power electronics, and can likely integrate them into existing functionality (boost/buck converters) in way that allows them to make much better use of them than they could if they had to add them as a discrete/external cap bank.
Any of you caps fans ever tried to think of nightmare of integration caps with battery?
Oh and anyone dared to look at pdfs to see specific energy? Less than 6Wh/kg...
Lets make example. Battery is near full and you need to regen 70kW for 4 sekonds that's over 70Wh. That's over 12kg of supercaps . But you need Dc-Dc electronics too. Why not sumply add 40kWh of batteries then...
Now ot about that optimistic 20% increase in battery specific capacity . Let's not forget that current cells have real world 250Wh/kg while on paper they are about 270. So talking like 20% are for granted looks funny...
Oh and anyone dared to look at pdfs to see specific energy? Less than 6Wh/kg...
Lets make example. Battery is near full and you need to regen 70kW for 4 sekonds that's over 70Wh. That's over 12kg of supercaps . But you need Dc-Dc electronics too. Why not sumply add 40kWh of batteries then...
Now ot about that optimistic 20% increase in battery specific capacity . Let's not forget that current cells have real world 250Wh/kg while on paper they are about 270. So talking like 20% are for granted looks funny...
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