Tesla Says Sub 10-Minute Supercharging is Possible

JUL 19 2013 BY ERIC LOVEDAY 34

Can a Tesla Model S be charged in 10 minutes?

Tesla's Proposed by 2015 Supercharger Sites

Tesla’s Proposed by 2015 Supercharger Sites

How about in 5 minutes?

Tesla’s chief technology officer, JB Straubel,seems to think so, but don’t count on it being a possibility anytime soon.

In an exclusive Supercharger-related interview with MIT Technology Review, Straubel stated:

“It’s not going to happen in a year from now. It’s going to be hard. But I think we can get down to five to 10 minutes.”

Why then would one need battery swapping?  You probably wouldn’t if a 5 to 10-minute charge was possible.

But it’s not.  Maybe it is possible, but feasible?

The current Supercharges out there deliver up to 120 kW.  If Tesla scaled that up to charge a Model S in 10 minutes, then we’d be looking at something like 720 kW.  The heat generated while charging would be a major issue at 720 kW.  To which Straubel says this:

“To do that kind of charging, everything has to be designed and working in perfect synchrony.”

But perhaps the biggest hurdle to overcome at that rate would be the sheer size and weight of the required charging cable.  We’re looking at something in the 1,500-volt and 480-amp range to carry those 720 kW.  That cable would be a monster and we see no way around this problem.

In Tesla’s defense, Straubel says that the current 120-kW Supercharger “seemed pretty crazy even 10 years ago” when conventional chargers delivered under 10kW.  So, maybe this theoretical 720 kW Supercharger is possible…in time.

But what’s the work-around solution for the size and heft of the cable?  We don’t see one.  Do you?

Source: MIT Technology Review

Categories: Charging, Tesla

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34 Comments on "Tesla Says Sub 10-Minute Supercharging is Possible"

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Or they could build a small, 2000 pound, aero, 2 seater, with 150 mile range, 24 kWh pack, and 10 minute fast charging. But who would buy that?

Well.. then maybe don’t use a gigantic cable. Perhaps some kind of “supercharge zone” you drive over and then two giant contacts come up from the ground and connect with the car somehow. Or, perhaps some kind of automated charging arm that attaches to the side of the car.

Frankly, I think the best solution for EV charging is miles-long inductive “charge lanes” on freeways everywhere so you can charge without stopping.

Exactly….by then inductive charging will be key. Stockton, CA electric buses get charged in 10 minutes through 500kWh inductive charging. Just like the battery swop, the big charger will be under ground and and under the car.

But at 300 EV miles, most would have charged up before leaving home, and won’t be driving 300 miles before returning home.

Which is why the battery swap may be the best fast charge option for those traveling across the country.

Did you mean 500kW (rate), or is the battery energy 500kWh?

The Proterra system is a conductive system. Currently the largest inductive system is from Bombarier, and weighs over 300kg on the vehicle. Conductive is the only way right now to get high power. Our Opbrid system can handle up to about 700kW, but 240kW is more typical for buses. Yes, the cables and connectors for this size power is not easily handled.

I still don’t understand this fixation on ultra-fast charging for cars. How often do you drive 600 miles in a day? Why not keep your old gas car for long road trips, and use the electric for daily driving?

I don’t intend to store, maintain, register, and insure a 2nd gas car for the few long trips I make a year. I will just rent something those times.

I think that HOV or HOT lanes or even tollways should have inductive charging on the roadway. It would justify the toll, for one. It should be easy to run high voltage lines down the median. I could easily see something like I-15 from Los Angeles to Las Vegas having this, with power from a few solar and wind farms.

I wonder why they can’t just up the voltage more, to decrease the size of the cables?

Use more than 1 cable.

That’s how I usually respond to this. Why can’t the battery be separated into say 4 banks, and use 4 cables, one for each bank?

Alaa says ‘Use more than 1 cable’ – my thought precisely! Since the Pickup trucks we used to use for work crews had two tanks – we used to find gas stations that had pump hoses long enough to fill both at the same time! In this case – the battery pack could be sub-divided in charging such that there were 4 sub-packs of about 22 kWh each, and just bump up the Chargers a bit more to 150 kW – and use 4 Connections: Voila – a 600 kW Charger system! The Charging would almost be done by the time you finished connecting the 4 ‘Hoses’ – so to speak, unless the car’s control said when to start the transfer of power – waiting until all 4 connections were confirmed! It would likely require a different set of charger entry points rather than the concealed clearance light spot of today! Maybe a Hood/Nose Variant Like the LEAF, or a rear version of this idea. Sorry kdawg – I didn’t scroll down enough to see your post before replying! – Agreed! I saw a variation of this done with charging batteries for an Electric Aircraft at EAA Air Venture Oshkosh… Read more »

1 step is 120kW
2 step is 240kW
3 step is 480kW
4 step is 720kW
there must be the development of this technology, step by step.
Using the super conductive wires.

I was not aware of the cable size problem. I was still stuck on the fact that no mass production lithium cell technology presently can do any better than to get from 20-80% in ~30 minutes. If they were looking at a 500 mile battery pack, say, 120kWh, that would allow 200 miles in less than 10 minutes at a few hundred kW. That would really be something, but you can’t ever get past the 20-80%/30minute rule with current cell chemistries, that I’m aware of.

13.5 kV would be about 60 A. Not sure how you shield it not to fry people, but it wouldn’t take much copper.

Increasing voltage while decreasing current allows for higher power to go through smaller wires. It might get to the point where they’re sending 10000V through the line, having it step down to the appropriate voltage in the car. Currently (no pun intended), DC chargers send the correct voltage for the battery pack to the car. If they bump up that voltage and have the car itself step it down, the “thick cable” problem will be solved.

I do think we’ll see it go up to 200kW charging to cut the time in half from 20-30 minutes to 10-15 minutes (to 80% or so), but I don’t think it’ll go up beyond that due to issues with cable diameter. The other thing to remember is that if they make longer range cars with larger batteries (125kWh), the “80%” point is much higher, and that means you can charge it faster for longer (see the “rate of charge” graph on the Tesla supercharger page). If you can get to 50% in 20 minutes, but then it takes another 20 minutes to get to 80%, on a 85kWh battery you’re adding about 6.6 miles a minute for the first 20 minutes, but then only 4 miles of range per minute for the next 20 minutes. With a 125kWh battery and a boosted supercharger unit and the same 20 minutes to 50%, 20 more to 80% rules (which makes sense because you’re charging the batteries in parallel so you just need more current), the first 20 minutes is 9.75 miles per minute, and the next 20 is 5.85 miles/min. This is a boost of nearly 50% in charging speed. To… Read more »

While someone at Tesla is exploring UberCharging ™, Tesla buys a test track. That new Roadster Prototype must be getting closer…

http://www.mercurynews.com/business/ci_23694920/tesla-buys-land-test-track-fremont

This charging capability is not a big problem. It just does not fit the current paradigm. This would not be hard for Tesla to accomplish. Present Tesla tech would allow a 10 minuet full charge from the battery point of view, they do not have the cooling capacity in the car presently to accept such a charge, but that is not difficult to engineer for the next gen design. In fact they know it will be necessary to provide such a charging rate because battery capacity is increasing rapidly. It is likely in 10 years that inexpensive batteries with 1000kWh/Kg will be common, that is currently 4 times the capacity of Tesla’s Panasonics and the likely cost of the most promising is $50 a kWh costing $5000 for the 350kWh pack. If such a battery were put in a model S it would have a range of 1000 miles and weigh the same amount as now. You would need to be able to charge such a battery rapidly and as others have mentioned ultimately that should be done inductively at a station. But a cable could be used as well. A 4800v line would be the same thickness as the… Read more »
Well here’s my comment from a few days ago regarding J.B. Straubel on Plugincars.com: · Bill Howland · 3 days ago Ok, sorry, but this article is the biggest pack of nonsense I’ve heard yet on plug in cars. 1). The numbers don’t make sense. 720 kw * 5 minutes is 60 kwh. 80% of 85 is 68 kwh, usually. Where is the magic 8 kwh going to come from? Ok, lets assume it had a 9.4 % charge when parked and wasn’t totally dead to start with.. “…The faster you charge a battery pack, the hotter it gets……” Where does all this heat come from, if we are not taking losses into account. 2). Since we have to take into account losses, lets say 720 kw for 10 minutes. Maybe Tesla will float another stock offering and then have enough cash to build these 10 minute “Hyperchargers”. Meanwhile, the charging cable is going to be 1500 volts at 480 amps. Seeing as Tesla’s own EVSE futuristic looking 80 amp thing supposedly overheats and the owners have been told to not use more than 60 amps, I’m not sure I’d let Tesla design this one. Plus they better have a… Read more »

I went and looked, and they realy did seem to get it from you. It is because of what they… I mean you said, that I wrote the piece above yours. Did you read it? The problems you mentioned are just not that insurmountable from an engineering point of view. Most of what I said solves the problems you mention with some engineering. This is something that Elon and his team are good at. Straubel especially. The current model S does not have the thermal management sufficient to protect the battery from a 720kw charge rate to full charge, not to mention the connector could not handle the current nor could their internal wiring and a host of other easily fixed reasons. I am not privey to their technical data, but taking that rate for 4 minutes from 20% SOC gets them 48 kWh or 130 miles of range without the battery getting into the high resistance range of the charge and I am fairly sure that the cooling system on the current car could handle that much charge for 4 min.

Well as far as writing stuff in the distant past, here’s more as to why I’d think 4800 volts won’t be used… “….· Bill Howland · 2 days ago @Priusmaniac Why stick to a “low” 1500 volts? Because it is the highest voltage that reasonable cost (under $1000) connectors exist.. Once you get over 2000 volts you have alot of problems with corona and keeping water away from the connections, etc… 1500 is hard enough.. The only reason ‘commodity’ lowcost solutions exist is because of use by the oil-pumping and mining industries. So unless Tesla wants to reinvent the world, I would imagine they would have 1500 volts as an upper limit. They have problems with those red and silver 80 amp EVSE things. A red roadster owner friend of mine recently got his model S and was told to not use the thing at 80 amps. but derate it to 60 because the thing has a problem of overheating at 80. Also, he says he has burned out 2 – 40 amp uninversal mobile connectors on the Roadster (I don’t have this problem, I unlike 99.9% of other Roadster owners, use a j1772 adapter only). So Tesla apparently needs… Read more »
Bill I am not sure why you keep bringing up the Tesla HPWC over heating problem, and some how thinking it represents all of Tesla’s Engineering. It was solved a while ago and it was a minor issue with the built in fast blow fuses unable to handle the cars current ramp up speed, it was just a software mod. There is existing tech out there for DC high voltage up through 10KV using low durometer coaxial positive core, negative shield conductor that would have no corona problems. The power coming from the current super charger is DC and corona would not be a problem for ten times the voltage with this coax cable tech. It has been around in similar form since 1919. Of course today’s insulation materials can be much more flexible than the rubber in those days and would be about as stiff as the current 120KW SC Cable. You are correct that water tightness during charging is critical in such a high voltage design but far from impossible. The mine cables you mentioned use fairly inexpensive connectors and they also need to achieve non arching water tightness which they do in rugged industrial environments. Arching issues… Read more »

Sorry Brad… P = I * I * R. A 6 fold increase in current will cause a 36 fold increase in heating. And that’s assuming R doesn’t increase a bit as well, but even you say it will go up a bit.

If all these problems are so simple as you say, then I don’t see why Tesla didn’t anticipate them. The UMC’s melting were particularly jaw-dropping when my friend told me about that.. And there was no software change for the UMC’s. They had to be replaced. The other problem to my friend’s knowledge is still pending. Perhaps you were describing an unrelated problem.

Bill Actually you are to be commended. The tenacity with which you stick with your understanding of a problem is laudable and it is a fine thing that you have expressed yourself in the end with your understanding of the math involved. Most posters I have conversations with dealing with math, physics and engineering end up flaming me or name calling because they do not want their point of view changed. Some people like to learn, but at the same time they won’t be buffaloed by someone they don’t know making unusual claims, but they change their point of view when sufficient proof is provided. Here is the proof and the point of my increased voltage suggestion. You are totally correct that “P = I * I * R” and then you state “A 6 fold increase in current will cause a 36 fold increase in heating” and this is completely correct, if the voltage stays the same. But if we use your example and increase the voltage 6 times then the resistance heating falls by 36 times, completely canceling the increased heating from the greater power, because P = V*V/R which is the point of my suggestion of raising… Read more »
Two comments: 1). I’m talking about any given battery cell. To charge the car’s battery as a whole 6 fold faster means each individual cell needs to have a 6 fold current increase. Unless you change the type of cells used, I don’t see anyway around not increasing the current IN THIS CELL 6 fold. I’m not talking about voltage drop through the contactor or cable which is trivial at either 1500 or 4800 volts.. P.S. Thanks for the vote of confidence. 2). The Roadster UMC was designed for 40 amps continuous use on a 50 amp circuit. Other values, sorry, aren’t germane. 3). I let the point about the 80 amp highpowerconnector slide, but I don’t know what kind of fuse would blow by “ramping up to 80 amps too quickly”.. The heating of the fuse is larger than the square of the current at all times (since the fuse eventually gets up to ‘operating temperature’), so unless the car temporarily overshot and drew 400 amps for a 1/2 second or something, I don’t know what would blow it. There must have been an overshoot to blow this fuse, otherwise its physically impossible (if this indeed was the whole… Read more »
Bill 1 We have covered several things in our conversation that address the various problems associated with very rapid charging. In regards to the single (or any number) battery you mentioned, it is true, given any specific battery charging 6 time faster will cause 36 times the waste heat. It is also true as you mentioned “Unless you change the type of cells used, I don’t see any way around not increasing the current IN THIS CELL 6 fold”. In fact a different cell is exactly what I was talking about, and is why I mentioned the lower resistance of the best lithium ion currently produced in my last post, because I am not privy to how much lower the New Envia battery’s internal resistance is than the current best Lithium Ion. It is supposed to be dramatically better (lower) because of the greater surface area of the nano-particle anode making very rapid charging very practical from the battery heating point of view, compared to, say the current Leaf prismatic or even the current custom Panasonic 18650 in the Model S. In the first part of my last post I am talking about the balance of system for a much… Read more »

I think a ten minute charge time is the wrong goal. With Superchargers giving 20 minutes, I can grab a quick bite to eat and use a bathroom. With battery swapping I don’t have to get out of the car. But what am I going to do for ten minutes? Smoke a cigarette? I stopped ages ago.

I agree. Tesla’s new 120 kW SuperChargers allow 200 miles in a 20 minute stop. I don’t need shorter 5-10 minute stops. Tesla may need them to get CARB “fast refueling” ZEV credits, if CARB completes their process to invalidate battery swap as a means to get these credits. This process has been started by CARB.

I would rather have the existing Superchargers in more places. However, if Tesla can still do that and also speed supercharging up enough to get the fast refueling credits, that would be great!

GSP

Part of the value to Tesla in increasing the charging rate is to reduce the number of spots needed at each station. Each slot is incrementally more cost to Tesla. The less time each car spends in a spot, the less spots needed.

The is also probably some marketing advantages to saying your car charges faster than any on earth as well.

I agree that a 20 minutes stop every three hours is really the sweet spot for almost any driver. I see that as 225 miles of range (@75 mph) in 20 minutes. Two stops gives you a 600+ mile day. Almost enough to get across Texas…

Can you charge 1 cell in 10 min to 80% if so its possible the rest is just engineering if not you can t you need new cells bigger or shoter cables are quite simple really

What is the area available under a Tesla? If 4 m², isn’t enough as connector section, then what?

This is for Brad B. Well, I think you’re playing word games here… As far as batteries go, yes I was assuming the battery in a model S since that is what was being discussed. Nowhere has it been suggested the the existing several thousands of model s’s are going to have their batteries replaced free of charge. Future batteries with lower “R’s” of course can be charged faster, but that’s just a sleight of hand. I don’t know what car you are talking about but I’m talking about the current model S. Sorry, one thing you just have to be wrong about is this ‘ramp up’ deal. The AC Through the fuse presents no problem. Almost all mainstream fuses can withstand normal RMS heating, and most, in fact are allowed only on AC circuits (their DC rating, if they have one, is much lower). Ramping up too fast cannot blow a fuse, period. The greatest heating is when the ramp up is ‘finished’ and they are taking the standard 80 amps RMS, with the fuse at ‘operating temperature’ i.e., its highest R. If a 100 amp fuse is blowing under a constant 80 amp loading, then Tesla Engineers have… Read more »
Bill There you are. I did not see you down at the bottom of the posts, The last thread was getting a little narrow ;^) First, I never “play word games”. I am usually a lurker and on those rare occasions I do comment, that is usually to an article, not to a commenter, in fact, I rarely read the comments. Even more rarely do I respond to a poster. I rarely read Plug in Cars, and even more rarely read commentary there, I have never posted there. When I do post here, I have no ulterior motives. Just the facts or a forecast based on the facts and some times a little humor, very little. You have only my other posts on this site including our interaction as proof. In my last post I tried to show in good faith where there were reasons why we seemed to be talking at crossed ideas. What I explained was somewhat complex and lengthy but those words were what were necessary to convey the reasons why I responded to the problems with the HPWC and the UMC for the Model S, not the Roadster charging options to which you apparently were referencing… Read more »

Thanks for the kind words. My last word? A crappy design is a crappy design. Don’t get me started on the 1840 watt continuous loss of the NY Times driver Test Drive of the Model S outside his motel overnight. (My Roadster loses much less battery capacity in this weather). Tesla either lost some great enginneering talent in the 3 young engineers who died while coverting a Lotus Elise to a Roadster, or else, it was just a lucky accident that the Roadster battery is much superior to an “S” in cold weather. They are selling plenty of them in Norway, so Musk’s days of deflecting the issue to keep his stock price up are numbered, unless of course he can get the model “s” ‘s “Sleep Mode” perfected by this winter.