REPORT: Tesla Model S was designed with battery swaps in mind
Tesla Model S - Click above for high-res image gallery
Recently-resigned Tesla Motors engineering chief Michael Donoughe revealed an interesting tidbit of information on his way out the door. Speaking to Green Car Advisor, Donoughe said that the Model S has been designed to accommodate fast (sub-five minutes) battery swaps. While a quick battery exchange has implications for how the car would be received and used in the real world, Donoughe said that it also helps at the factory when the car is assembled. "As long as you're designing for manufacturing and assembly you can also design for manufacturing, assembly and swap. That's basically what we're looking to do," he told GCA.
Tesla's design "is not at all wedded to Better Place," Donoughe said, referring to the biggest proponent of battery swap technology. The two companies' technologies could work together, he said, but don't have to. Considering that Tesla is planning on selling the Model S, due in late 2011, with different battery options (a base model with 160-mile range pack; and then more expensive packs with 230-mile and 300-mile ranges), figuring out how to swap these different batteries in random locations seems like a logistics problem of tremendous proportions.
Gallery: Tesla Model S
[Source: Green Car Advisor]
Reader Comments (Page 1 of 2)
mike 7:35PM (9/27/2009)
Well.. the nice thing there is you could upgrade in a couple years to a newer tech maybe or a bigger pack.
That kind of easy upgrade path is a fetching selling point if they chose to make it one.
One thing I am hoping to see as we go forward with electrics and different types of hybrids is some modularization.
Reply
Mark Kiernan 8:00PM (9/27/2009)
Strange I would have thought that Tesla would be going for the recharge option more, but giving consumers both options is the right way to go about it.
Reply
PopSmith 8:27PM (9/27/2009)
Tesla may have designed the Model S with swapping in mind, I believe Elon mentioned swapping in one of the three videos on "OnCars.com".
One reason they may have done swapping was because it allows their customers to swap the battery pack for a larger one at a later date if they wish without too much complication.
@Mark Kiernan, I'm not sure what you mean by "recharge option". The Tesla Model S batteries will, obviously, be rechargeable. Tesla may just "setup" the option to swap the packs in a much quicker time frame vs recharging it for when someone is on a road trip etc.
jake 8:34PM (9/27/2009)
From the initial talk when the Model S was introduced, I didn't think the Tesla is necessarily going for a battery swap option like Better Place has. What I got from it was that it allows a user who buys a smaller 160 mile battery for their car to be able to go to their local dealer to rent a 300 mile battery for longer trips.
Tesla still supports the rapid recharge path as they are still developing a 480V, 45minute charger for the 300 mile battery. In general, I agree that it is good they give customers the choice in case one option develops faster than the other.
BTW to Sebastian, you seem to have the wrong links to the article, it should be this one if I am not mistaken:
http://blogs.edmunds.com/greencaradvisor/2009/09/teslas-model-s-electric-sedan-is-designed-for-quick-battery-swaps-executive-says.html
Sebastian 6:12AM (9/28/2009)
jake - thanks for the catch. has been updated.
cheleball 8:52PM (9/27/2009)
I seem to recall this being mentioned even from the initial unveiling. Far too lazy to confirm that at the moment, though. :)
Reply
Nick 9:44PM (9/27/2009)
That's SMART:
1) It allows for both options, charging or swap.
2) It allows for future upgrades, in 5 years from now you could get much cheaper pack.
3) These wheels are beautiful
4) The huge screen in the dash has got to go; after a day of work in front of a computer, I don't want a drive home staring at another one making my eyes bleed!
Reply
Doug 9:42PM (9/27/2009)
It was mentioned at the initial unveiling back in March. I was there. Not sure what's new information here.
Reply
jpm 9:48PM (9/27/2009)
Ha, I wonder how much of that "300 mile" range you'd really get? My guess 1/3 of it: 100 miles.
If they are padding the specs big time, then EV mfgs are in for some consumer backlash when people start getting stranded because they ran out of miles.
Reply
polo 3:13AM (9/28/2009)
When they tested the roadster it went the full range and then some.
shut up.
jpm 3:31AM (9/28/2009)
No, see the the top gear episode were it petered out at half it's range. Sorry, but you're wrong.
Geoff de Ruiter 3:54AM (9/28/2009)
@jpm
If you actually followed the story of that topgear episode the car was not out of juice at that point and they were only simulating what you would have to do in that situation. The facts are there.
I do agree that aggressive driving drops the driving distance, but if you were going on a small road trip in any car you would not be doing burns outs off every line. You would take it easy and drive smooth. I.e. just like in these electric cars their performance usually is accurate when looking at driving range, and not driving 100 mph.
You can still hypermile in an electric vehicle too!
skierpage 4:02AM (9/28/2009)
@jpm,
Please don't confuse Top Gear entertainment with actual testing. They admit they faked the Roadster running out of juice and they have NEVER explained how they came up with a range of 53/55 miles.
http://wheels.blogs.nytimes.com/2008/12/30/was-top-gears-test-of-tesla-roadster-misleading/
kert 1:31PM (9/28/2009)
Time for highway and city ranges of EVs.
Obviously driving on highway has higher energy requirements, so range will be shorter.
Driving in city has smaller energy requirements, and regen braking helps with stop and go.
A honest EV manufacturer would publish both city and highway ranges, as is done with ICE cars city and highway economy.
Jeremy 2:38PM (9/28/2009)
@ jpm
Tesla certainly does not pad their mileage estimates. In fact, the 244 mile stated range for the Roadster comes from the EPA, not Tesla, and it's based on their combined city/highway driving test, which also includes using things like air conditioning for some amount of time. Not only that, but the car will and DOES do that range. It wasn't long ago that a Roadster completed a road rally in Monaco where it went 241 miles and still had ~38 miles left according to the computer (which is estimating that range based on your energy use over the last 40 miles of driving).
Additionally, if testing actually did confim 55 miles of range while driving on a race track, that wouldn't be anything to look down upon and is no different than what you would find in a gas-powered car. Road course racing consumes gasoline like crazy, and Top Gear has even shown this before in multiple episodes -- cars like the M3, which usually get great gas mileage, can average like 6 mpg in road course use. Like many cars sold for street use -- even quick, sporty street use -- the Roadster is not a track car out of the box. If you expect to race it on a road course, things like higher performance brake pads and fluid, maybe coolant upgrades, better tires, etc, are often required just like they are on any gas-powered sports car. Track pads do not belong on the street, and even massive brakes can easily overheat in a track environment with street pads installed.
Anyway, Tesla wouldn't sell a "160 mile" battery unless it really did that. And these ranges are combined city/hwy, btw.
And +1 on not knowing why this is supposedly an update or any sort of breaking news. Tesla has stated since the very beginning, when this sedan was just a concept, that it would have quick-swap battery ability.
Dave 10:37PM (9/27/2009)
Some discussion of Roadster range here:
http://www.teslamotorsclub.com/tesla-roadster/2919-real-miles-drive.html?highlight=highway+range
If you want to get the full 244 mile range, you have to damage your battery. And the range is also very sensitive to driving style and other factors.
Reply
Jeremy 2:53PM (9/28/2009)
"If you want to get the full 244 mile range, you have to damage your battery."
Maximum lifespan of a lithium ion battery is certainly achieved by keeping it above 10% charge and under 90% charge, and that is what the Tesla does in its normal driving mode. Therefore, you're using 80% of the battery's capacity on a normal basis. However, using that top 10% and dipping into that bottom 10% every now and then will not negatively affect battery life in a way that will be noticeable to you. It certainly does not *damage* the battery. If you do this every single day you can expect your battery to lose total charge capacity quicker than a battery kept in that ideal range all of the time, but it's something that takes years to notice and the difference should not be too large. If you're doing it once in a while (once a week or whatever) because you have a long trip to make, it's really not something that should worry about.
Tesla estimates 75% charge capacity left at the end of 7 years. It looks like this is a fairly conservative estimate, as Tesla has a few battery packs that have been undergoing, well, torture testing for quite a while -- extreme hot and cold temps, extreme humidities, horrible vibration testing, rapid and repeated charging and discharging, etc -- and they have approximately 93.5% capacity left after ~5 years of this.
Really, the heart of Tesla's technology is the battery management software and hardware. The system does everything possible to maximize the life of the battery, and that includes never allowing it to overcharge or discharge completely. You should not be afraid of using range mode if you need to in order to get where you're going.
jake 3:04PM (9/28/2009)
You don't "damage" the battery. It just lessens the life cycle of the battery. Damaging would imply you are permanently breaking cells, but you are not. You are just degrading the cell faster when in range mode (it is going to degrade even in standard charging mode). That means if you charge occasionally in range mode and most of the time in standard mode, the total rate of degradation isn't going to be dramatically different. To really "damage" the cells you have to overcharge them and even in range mode, it doesn't allow you to do that for safety reasons (for one there is a danger of the cell overheating, catching on fire/exploding if you overcharge it). If you damage the cells, you will see the effects, even if you do it only one time.
Also if you pay attention to the numbers, the owners can still get ~170-180 miles in the Roadster in standard mode. Range mode is supposed to be reserved for longer road trips and since I visit that site frequently, I know the owners there have gotten 200+miles on range mode, none have gotten 100 miles or less like jpm is suggesting. So it is still within 80% of the EPA combined range. So in 300 EPA mile pack you can expect to get around 250 miles.
BlackbirdHighway 3:50AM (9/28/2009)
The nice thing about the Model S swapping is that you could get the car with the 160 mile battery for day to day driving around town, then rent the 300 mile battery for when you go on a trip.
That avoids some of the concerns people have with PBP, such as trading in a fresh battery for one that's stale or having to buy a subscription to battery swapping when it is only needed occasionally.
Reply
Laurens 4:00AM (9/28/2009)
I'm always a bit amused by the green communities focus on performance. Apparently there is a misunderstanding about what 99% of current users find important.
One of the mayor car companies is doing a field study with some 200 electric rental cars. They found that initially users tend to accelerate very fast, but after a short while start to focus again on range. That's also what I have when I drive a fast car, a few sprints at first, then you start to get annoyed by the seats (or something similar).
OT: wise to keep both options open. It may very well be that in Europe at least, we'll go for the battery replacement system. The cost of installing 3 load points (and the associated transformers and power lines) per car is such, that the investment will never be paid back by electricity sold.
Our current fuel stations are conveniently located next to the motorways, so no need to make a detour. We just need to built battery storages to replace underground fuel tanks. It will only work if battery dimensions are standardised asap. A bigger car will just have to get multiple batteries replaced in one go.
Reply