Since you're usually very good at predicting do you believe Tesla will use the latest Model S batteries or a new improved battery chemistry?
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New Roadster Goodies for 2014
- Thread starter hjr
- Start date
Since you're usually very good at predicting do you believe Tesla will use the latest Model S batteries or a new improved battery chemistry?
dhrivnak
Active Member
I predict the new chemistry that is likely planned for the Model 3. It was widely known the Roadster was the test platform for the Model S. I do not think the Model S cells will give us the impressive 400 miles desired.
JRP3
Hyperactive Member
Assuming they intend to produce the upgraded packs in 2015 I'll assume they'll use the same Model S cells going into cars now. If the packs aren't going to be built until after 2015 then there could be a chemistry upgrade, but I'd think it would show up in the S and X first. I'll further confuse the issue by speculating that some of the delay for the X may be testing of a slightly improved cell to keep the range up for the larger vehicle. 3.4ah cells should be available with enough testing for stability and cycle life, but I don't know if they are mature enough for Tesla to put them in a vehicle.
But the Roadster did not use the cells that went into the Model S.
But the Roadster did not use the cells that went into the Model S.
The next 18650 cells on Panasonic's roadmap after the 3400 mAh cells used in the S were 4000 mAh cells, if I remember correctly. If they will be ready for the new Roadster pack the increased capacity would boost the range from 240 to 400 miles, using the same (old) 2-cycle EPA test. The existing Roadster packs use 2400 mAh cells. 240*(4000/2400) = 400 miles.
One problem would be the 4000 mAh cells were quite a bit heavier than the 2400 or 3400 mAh cells. The extra mass might (or might not) be too much to use them in the Roadster.
GSP
One problem would be the 4000 mAh cells were quite a bit heavier than the 2400 or 3400 mAh cells. The extra mass might (or might not) be too much to use them in the Roadster.
GSP
The Roadster cells are ~2.2Ah units. The Model S cells are ~3.2Ah. That's about 45% more energy
Assuming you just swapped the Model S cells in to the pack, you'd take it from a 56kW to a ~81kW pack. With a 245 mile on the existing pack, one upgraded as such would seem to be good for only about ~355 miles...
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dhrivnak
Active Member
I agree the Model S used newer cells as it should. But the basic design was tested in the Roadster. The Model S cells are now 3 years old. And like you I suspect the Model X will use an upgraded cell. So why come out with a "new" pack based on 3 year old technology? So if new cells are coming, and we all know they are, it is MUCH better to field test those cells in a smaller number of Roadsters than risk problems with the Model X.
JRP3
Hyperactive Member
After much discussion and research I think the consensus is Tesla is using 3.2 ah cells in the S.
The question is timing, i.e. how soon will Roadster packs be available and will the X actually be using a more energy dense cell. I don't subscribe to the idea of using the Roadster or any customer vehicle as a test bed. They need to be 100% confident in cell performance before putting them in the hands of the public. As for using "old" technology in the new Roadster pack, if they are indeed using newer cells for the X they may very well need all of them for that vehicle, assuming the newest cells will be the most production constrained at first.
Curt
Roadster Signature #55
I (mostly) disagree with NigelM's disagreement with Juanmax. :wink:
While I don't think we will get supercharging, I would welcome it, and would gladly pay for it.
I also don't think I'm "typical", but I do take my Roadster on longish trips, and could easily see myself supercharging 1-2 times per month, if I were able to. In the past year alone, I've been on half a dozen cruises with Model S owners where I have Range charged in the morning, knowing that I would be sitting with them at a supercharger at some point during the day, and would have to make it through the day on the single charge.
bonnie
I play a nice person on twitter.
From a technical standpoint, I think we've already concluded the expense is far more than $5k. So while a nice number, it's not realistic. And nothing Elon has said publicly about this would lead anyone to believe that supercharging would be considered. He has ONLY talked about an increased-range battery. That's it. We could vote on it or have another poll. 
But y'know .. Tesla. Their call.
But y'know .. Tesla. Their call.
JRP3
Hyperactive Member
In theory all you'd need is the charge port and a direct cable path to the pack through high powered contactors and some signalling circuitry. It could be as simple as adding a second charge port with that hardware. I think it could be done for much less than $5K. However I don't think there is much chance of it happening.
bonnie
I play a nice person on twitter.
JRP3
Hyperactive Member
Probably right. My engineering is more along the lines of "Let's cut a hole here, run the cables there, hook them up, and it should be good". :smile:
You would also need some kind of contactor to switch the power (otherwise you will electrocute someone). And a means to detect ground fault conditions etc. Plus you would have to make all the cabling into and within the battery pack more robust. It's one thing to deliver > 100 kW for a matter of seconds; another thing altogether to sustain it for an hour.
That said, I do think the engineering would be very expensive, and is the biggest roadblock.
That said, I do think the engineering would be very expensive, and is the biggest roadblock.
JRP3
Hyperactive Member
I"m assuming there is a small controller that sends the handshake signal to the SC, which energizes it's contactors, after the car battery pack contactors are engaged. My thinking is you'd want the car battery pack contactors to close with no load, to save wear, and let the SC contactors do the live switching.
I doubt the Model X will use a different cell from the Model S. The X battery packs themselves will be no different from the Model S pack in shape and design. So why would Tesla create the possibility of mixing up the two? The Roadster, on the other hand, is the perfect test bed for real world experience with the Gen III/Model III battery. I'm certain Tesla is 100% confident in the battery since they are betting $5 billion on a factory to produce billions of them. However, having physical experience with the battery and how it performs in an actual car would be priceless information. If they put them out in 2015, Tesla would have two years of hard data before they get them into the Model III. It sure makes a lot of sense to me. That's if it can be done.
wiztecy
Active Member
Tesla won't use an "experimental" cell technology in the Roadster, too much of a liability. Also for the most part the Roadster owners who'd pick up this new technology will be the one's on a need by basis (low CAC/Range or need a pack due to other reasons), others who have to by now since its cool factor, or the ones who bought the battery replacement plan when they purchased their Roadster new. There's not enough test data on a new technology with some random non-technical Roadster owners. Yes there are some that are technical, but the majority are just owners/drivers/enthusiasts.
I'm sure Tesla would have their own mules, mostly Model S's out in the field working for Tesla, testing other new things along with the battery. Again it in no way will be the end consumers. Consumers can sue and consumers can make bad news if they're unhappy or feel they've been burned or hurt by a technology or company. Tesla test employee's can't, its their job and obligation.
From all the educated people who understand batteries here, it does appear to be the Model S cell platform and the range / fit appears to correlate well.
I easily can see the Model X using a totally different cell technology than the S. Its evolving, so much has been learned and tried since the release of the S. And with that Tesla would have done their due diligence in properly testing the newer technology in order to release it in a confident manner.
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JRP3
Hyperactive Member
I'm guessing they have better quality control than that, I don't think they track packs just by looking at them. I'm not sure they will use a different cell, but if they want to preserve range in the larger vehicle that's pretty much the only way to do it.
Which they will have in their own controlled test fleet, not in the hands of customers. They didn't test the S packs in customer cars.
Since the new cells are going to be built in the GF, which doesn't exist yet, and the cells will be a different form factor, and still have another two years of possible development and improvement, it doesn't make much sense to me.
There is already one generation of cells past the model S cells out there. The really new, unknown ones are two generations further on with different anode. I can see the former being used.
dhrivnak
Active Member
While I agree Tesla would not use an "experimental" cell for a new Roadster pack I do see them using a newer technology. They will need to perform broad scale testing at some point and I believe the Roadster owners could be a perfect test bed.
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