The 500-mile Tesla?

[Benz]

If you keep the same charging rate ("C"), then a big battery charges at the same speed as a smaller battery. It gets more kWh/minute, but just in proportion to the size of the battery. Increasing C and shortening the charging time requires technology changes and/or greater stress on the battery.

Remember that there are constraints on the land-side, too. There are important but mundane issues like, how stiff and heavy is the SpC cable? What is the expense of making 270kW of power available at each SpC, thereby doubling the transformer and interconnection costs, the monthly demand charge from the utility, etc.?

Level 2 charging would still remain at 30A-40A in most places because of the cost of wiring and panel capacity. So, if you wander off the SpC Highway, you still might be limited in your daily driving, not by the battery size but by the amount of charge you were able to replace while you ate and slept. At, say, 10 hours stopped overnight, at 40A you've recovered about 300 miles of range -- a familiar number.

- - - Updated - - -


Personally, I can't see anyone being interested in paying for that much capacity. Batteries will never be free: not only do you pay for their capital cost, but you pay in performance for schlepping all that extra weight and volume around. There is a zone that balances these costs against the inconvenience of frequent/lengthy charging. I think most of us will agree that the Leaf's 70 mile range falls below that zone. For me, the 60kWh pack also falls below that zone, but it clearly is inside the zone of others. My guess is that 500 miles is at the top end of the zone, with 750 miles as an upper limit.

Note, though, that the zone shifts with the cost. If batteries were incredibly cheap, light, and small, then the zone shifts up. Battery tech has a long-run improvement rate of about 8%/year, so barring any dramatic technology breakthroughs, I think the zone of 200-750 miles will hold for at least a decade, with the core of the zone at 250-500 miles.

(What I want are the batteries from a light saber. Did you ever see Obi Wan looking for a place to plug in?)

That's very interesting.

Question:"Do you think that there will be a Level-4 Charging"?

 

[dennis]

99% of the time, it takes from when I get home at night until the morning to charge; therefore the same time even with a bigger battery.

A HPWC at 64 or 80 amps and dual chargers could fix that.

 

[Red Sage]

Energy density is the key metric of battery tech to watch. Density is expected to double every 10 years. So when Musk says that the MS has twice the energy density of the Nissan Leaf, he is basically saying that Tesla is 10 years ahead of Nissan.

Here, you've stated this point better than I've seen anyone else! Thanks! I had not managed to say this in such a concise manner myself. ;-)

This leads to a simple metric for measuring years lead in battery energy density. Suppose one technology has energy density ED1 and another has ED2. Then, I define the Years Technology Lead in Energy Density as

YTLED = 10×log (ED1/ED2)/log (2)

Once again, this is a great formula! It puts everything into a nice neat package. I typically use tables and charts and a bunch of prose to say what you put into a simple equation. Bravo!

So note that when JB Straubel points ... out that the Model S had a density gain of 40% over the Roadster, this implies a YTLED of about 5 years. Also if the upgrade for the Roadster achieves 400 range with a pack of the same mass, then this implies a 64% density gain, or 7.13 years gain (YTLED). This would be right on schedule. So I think this could be a useful way to measure progress.

I think that Tesla Motors has simply used the same battery cells as were being used in the Tesla Model S in 2012. That is, I expect this will be a ~85 kWh battery pack on offer for the Tesla Roadster. ;-) But I agree, it is likely that Tesla Motors will stay well ahead of the rest of the industry. I'm hoping to see a 120, 135, or 150 kWh battery pack in 2016.

 

[dsm363]

You are very optimistic indeed, and actually I do like to be optimistic too. But I still prefer to have conservative expectations. Just to avoid the risk of getting disappointed too much. Therefore I predict:

2016: 100 kWh
2020: 120 kWh
2024: 140 kWh
2028: 160 kWh

But still, I hope that in due time I will have say that I was too conservative.

This is much more realistic. Also, as packs get lighter you won't need the same kWh to go a certain distance (more efficient). Knock off 600lbs on the Model S pack and the 85kWh would take you a lot farther. I doubt 220kWh packs are needed.

 

[mountaineer]

Hi Guys,
Elon said that TM will be able to do 500 miles soon. This indicates the technology is already available. Potentially, there are two possible options for doing this, let's exam them:
1. Use a big battery, from 300 to 500miles, this will roughly double the number of cells in Model S and the weight will increase substantially. Can a car with this weight performs as good as Model S?
2. Use a new battery, such as a metal-air battery to extend the range? Not sure if this technology is mature enough.

 

[BlueTan85]

Why double the cells? If the capacity per cell gets a boost, you could keep same number of cells.

Tesla has been saying for years that batteries, unlike w/ Moore's law and semiconductors, improve only 7-8% per year. Fine, that is still a nontrivial gain. So when will we see gains? Model S has been out 2 years already.

 

[RobStark]

So when will we see gains? Model S has been out 2 years already.

Improvements don't necessarily mean getting EPA re-certifications every year or two.

Getting EPA certification is not cheap.

Maybe there have been gains without EPA certification.

You can't advertise fuel efficiency claims in the USA without it. My guess is there are similar laws in other countries.

 

[Tasdevil]

There will be a bigger pack in the modelX to make sure it can do 300miles with 8 adults, luggage, trailer etc.
So maybe the X will have something close to this size battery.

 

[richkae]

I have posted this in other threads, but a 500 mile car could be very easily made today.

You could take a Tesla Model S 85kWh pack and put it into a 1999 EV1 body and you would have a 500 mile car.
The 85kWh Tesla pack is approximately the same volume and weight of the 1999 EV1 NiMh ( 26kWh ) pack.
( You would have to repackage it, as they are not the same shape )

If they hadn't all been crushed, some home hobbyist could have already done it.

 

[DITB]

I think there will eventually be a range extender available.

No, not the one you are thinking of, no burnin' stuff here.

Imagine a place under the rear seats (or a similar place), where a bay of one more more extension packs could be placed. Just like you buy more memory for your computer as needed.

I already suggested this to Tesla Motors a while ago (didn't hear back, of course).

There could be some kind of vending machine at TM shops, service centres and superchargers, where you could rent or even buy road trip extension packs. Expand the range permanently or temporarily, so those 95% of your trips, you can use your normal battery, while for the occasional road trip, you juice up your car with a longer range.

How much would it cost, in a future Tesla car, to include those bays? That extra cost would be offset by lower weight, lower investment in batteries, while you still have the option and flexibility to change your range.


I cannot say it's a "no-brainer", I'm neither engineer nor financial expert, but so far I find it hard to see many downsides to this.

It's all the best of a range extender, less batteries used and invested in (and carried around daily), nothing burned or emitted.

Bought a 60kWh and cannot sell it because buyers want 85 or 120kWh? Not a worry if the car has this kind of extension packs, they can change it any time they want.

I would be happy to have 200 mile range, as long as I can change it later without an expensive modification.

 

[aronth5]

There will be a bigger pack in the modelX to make sure it can do 300miles with 8 adults, luggage, trailer etc.
So maybe the X will have something close to this size battery.

Why is it necessary to make sure it can do 300 miles especially pulling a trailer? Certainly would be nice but not required.
What I am more interested in will Tesla risk the chance that the Model X with the smaller 60 kWh battery will have a range less than 200 miles which seem to be Elon's magic number?
The S is EPA rated at 208 miles so the heavier Model X with the higher profile is very likely to be less than 200 miles. That may be one why they offer a larger battery.

 

[woof]

(What I want are the batteries from a light saber. Did you ever see Obi Wan looking for a place to plug in?)

I think you'd be disappointed. What the Jedi hide from you (using mind tricks of course) are the padawan running around finding places to recharge all the light sabers. Remember that power socket R2D2 accidentally plugged his data port into? Things like that.

 

[flashflood]

I think there will eventually be a range extender available. [...] Imagine a place under the rear seats (or a similar place), where a bay of one more more extension packs could be placed. Just like you buy more memory for your computer as needed. I already suggested this to Tesla Motors a while ago (didn't hear back, of course).

Cool idea, but it's definitely harder than it sounds:

(1) There has to be wiring to connect the spare battery. That's challenging because this is not wiring to a charging port, it's wiring to the powertrain, which must be able to carry over 300,000 watts during acceleration. Designing a 300kW connector that's safe to handle isn't trivial. But, worst case, this could be a service center install.

(2) While the connection points (in the frunk, say) are not in use, they must be safe for a toddler to touch, and must remain safe even if a gallon of milk spills on them. The meta-issue here is that because the range extender is optional, you're necessarily mixing the human environment and the powertrain environment. Cars in general, not just EVs, are careful not to do that because it tends to create safety problems for both the human and the machine.

(3) There has to be a way to cool the battery, because it will heat up under load. Not clear how to do that with a plug-in part. There could also be cooling tubes that are part of the install, but now things are getting complicated, and failure-prone (liquids are a pain -- most of them want to corrode things; all of them want to leak; you get air in the line, etc).

(4) It would require regulatory approval. Unlike a bag of groceries, the range extender becomes an integral part of the car. There would have to be approved strapping, connectors, crash tests, and all the rest.

Sorry to be a Debbie Downer. I'm an engineer. I'm paid to think of all the ways something can fail. Preferably beforehand.

 

[vinnie97]

This forum, with threads like these, regularly causes me to salivate! Pass the honey(comb) please!

 

[FANGO]

Why? Who cares. What a waste that would be.

Which is why they haven't made it yet. Because there's pretty much no reason to.

 

[Tasdevil]

Why is it necessary to make sure it can do 300 miles especially pulling a trailer? Certainly would be nice but not required.
What I am more interested in will Tesla risk the chance that the Model X with the smaller 60 kWh battery will have a range less than 200 miles which seem to be Elon's magic number?

You sort of answered your first question with your second.
Why would tesla announce an x60 with 200mile range, then say, you can seat 8 adults, carry luggage, tow a trailer and carry skis on top. But only travel 100miles if it's snowing or 140miles if scorching. (Wild guesstimates at range, but you get my point)

It's just not a good way to sell a car.

I watched a presentation from a tesla rep. (Can't remember his name) but he said they have been challenged to make the modelX have an uncompromising range.

 

[Matias]

Here's one plug in range-extender

Nomadic Power | 300 miles non-stop with EVERY e-car

 

[Red Sage]

The Tesla 500...

The Tesla Model S will never need 'a bigger battery'... The battery pack will never change size. The amount of energy stored within its individual battery cells will increase -- NOT the number of cells. The form factor of the battery pack, along with the size, shape, & weight of the battery cells within in it, will retain the same dimensions. That is because the casing of the battery pack was engineered as a fundamental structural element of the car.

In 2012, the type of batteries used in the Tesla Model S battery pack would have needed an array of approximately 11,300 cells to achieve a capacity of 135 kWh. There is absolutely no way that number of battery cells can be placed within the battery pack. They just won't fit.

However, if you presume an improvement in energy density over time, then an array composed of improved battery cells would produce a higher combined total with ~7100 batteries than what was achieved with the 85 kWh battery pack from 2012. I believe that an acceptable mark will be reached by 2016, and certainly by 2017.

PROJECTED kWh CAPACITIES
FOR FUTURE BATTERY PACKS
(GRADUAL GROWTH per ANNUM)
​

7%	8%	8%	8%
53	53
57	57
61	62	60
65	67	65
69	72	70
74	78	76
80	84	82	85
85	91	88	92
91	98	95	99
97	106	103	107
		111	116
		120	125
			135
			146
			157
			170

PROJECTED MAXIMUM CAPACITY
(MASSIVE GROWTH)

Year	2008	2012	2016	2020	2024	2028	2032
kWh	53	91	156	267	457	784	1343

(AGGRESSIVE GROWTH)
​

Year	2008	2012	2016	2020	2024	2028	2032
kWh	53	85	135	220	340	540	900

(REGRESSIVE GROWTH)
​

Year	2008	2012	2016	2020	2024	2028	2032
kWh	53	91	144	211	288	367	423

(PENSIVE GROWTH)
​

Year	2008	2012	2016	2020	2024	2028	2032
kWh	53	85	111	146	191	248	323

ESTIMATED RANGE
​

VEHICLE	EPA	DLYS*	DLHT*
Model ☰ 60	250	175	375
Model S 60	208	146	312
Model ☰ 85	318	223	477
Model S 85	265	186	398
Model ☰ 135	505	354	758
Model S 135	421	295	631
Model ☰ 170	636	445	954
Model S 170	530	371	795
Model ☰ 220	823	576	1235
Model S 220	686	480	1028

* DLYS = Drive It Like You Stole It
** DLHT = Drive It Like a Hippie Tree-Hugger
​

 

[jhm]

Elon Musk: Tesla boss on EVs with 500-mile range and colonies on Mars | Auto Express

Energy density is the key metric of battery tech to watch. Density is expected to double every 10 years. So when Musk says that the MS has twice the energy density of the Nissan Leaf, he is basically saying that Tesla is 10 years ahead of Nissan.

This leads to a simple metric for measuring years lead in battery energy density. Suppose one technology has energy density ED1 and another has ED2. Then, I define the Years Technology Lead in Energy Density as

YTLED = 10×log (ED1/ED2)/log (2)

So note that when JB Straubel points to out that the Model S had a density gain of 40% over the Roadster, this implies a YTLED of about 5 years. Also if the upgrade for the Roadster achieves 400 range with a pack of the same mass, then this implies a 64% density gain, or 7.13 years gain (YTLED). This would be right on schedule. So I think this could be a useful way to measure progress.

I must confess I am disappointed with announcement of a density gain of only 10 to 15%. In YTLED this is only a gain of 1.4 to 2.0 years. If this is going into production immediately, then that would be par. I hope they have bigger gains they're just not telling us about.

 

[Benz]

You are very optimistic indeed, and actually I do like to be optimistic too. But I still prefer to have conservative expectations. Just to avoid the risk of getting disappointed too much. Therefore I predict:

2016: 100 kWh
2020: 120 kWh
2024: 140 kWh
2028: 160 kWh

But still, I hope that in due time I will have say that I was too conservative.

After having listened to Elon Musk and JB Straubel and Deepak Ahuja on the Conference Call, I would like to change my predictions on the future battery packs for the Tesla Model S and Tesla Model X:

2018: 120 kWh
2022: 150 kWh
2026: 180 kWh
2030: 210 kWh