The 500-mile Tesla?

[Red Sage]

The Magic 8 Ball...

I think people may be misreading the 15% improvement that JB Straubel spoke of thus far... It really does fall directly in line with an improvement of roughly 7% to 8% per year in energy density for lithium ion batteries...

ENERGY DENSITY of BATTERY CELLS
(7% Improvement per Annum)
​

Year	85 kWh	60 kWh
2012	~7,100	~5,012
2014	~6,141	~4,335
2016	~5,311	~3,749
2018	~4,594	~3,243
2020	~3,973	~2,804

This is my least optimistic, or most pessimistic, projection. As usual, I could be wrong. But I think this is rather realistic. Tesla Motors will either use fewer batteries per car to achieve the same storage, or will continue to use the same quantities per car with better storage capacities overall.

PROJECTED BATTERY PACK CAPACITY
​

Year	Model S	Model ☰
2012	85 / 60	-
2014	98 / 69	-
2016	114 / 80	85 / 60
2018	131 / 93	98 / 69
2020	152 / 107	114 / 80

Unfortunately, it may take until 2021-2022 to get a 500 mile range version of either car, using this progression.

 

[Matias]

Why aren't we now seeing 98 kWh Tesla? Of course it is cheaper to build 85 kWh, but Tesla could sell 60, 85 and 98 versions.

 

[ecarfan]

Because they wanted to limit the physical size of the pack and with current cells a 98kWh pack would be larger than what they wanted.

My opinion.

 

[William13]

Tesla has access to more dense cells,but they weigh more and cost more and may not be tested. Due to the larger Model X they will likely introduce a larger battery soon. They are a for profit company. They will introduce the larger battery when they believe the time is ripe/right. There is no real competition and they are supply constrained currently. When this changes we will see a larger battery.

 

[TI Sailor]

I'm not an engineer, automotive specialist, or anything close. However, since no one has burned anyone yet in this thread for offering an idea, I thought I'd throw this one out and see what real engineers think:

I'm old enough to remember 2- and 3-speed transmissions. Now there are 7-, 8- and 9-speed ones, not to mention CVT's. Presumably the major reason for the shift (pun intended) to more and higher gear ratios in ICE cars has been to improve MPG and by logical extension Range. Might TM be reconsidering its use of a single-speed differential and possibly exploring something like a continuously variable diff (CVD) or multi-speed one (again I think), with the aim of reducing energy use at higher speeds while still providing high torque at lower speeds?

 

[Johan]

The cell dimensions could change from 18 mm radius/650 mm length. Elon and JB said on the Q2 call that their own modeling had shown the optimal size to be about 10% larger on both measures, yielding about 30% more volume per cell. I'm sure they'll find a way to stack these in a battery pack of today's Model S size.

If they go with larger format cells for Gen 3 they'll of course build the pack around that cell's dimensions.

 

[Model 3]

I'm sure they'll find a way to stack these in a battery pack of today's Model S size.

I don't think that can be done, the cells will be to tall. If they make a battery pack for Model S of this cells, it have to be higher.

Remember that when the GF is on-line, they will still be getting cells from other Panasonic fabrics. My guess is that is still 18650 cells for the GII series (TMS/X) and that the cells produced at the GF will be the new cells for the GIII series (TM3/Y). That's why the TM3 is totally depended on the GF.

 

[Johan]

I don't think that can be done, the cells will be to tall. If they make a battery pack for Model S of this cells, it have to be higher.

Remember that when the GF is on-line, they will still be getting cells from other Panasonic fabrics. My guess is that is still 18650 cells for the GII series (TMS/X) and that the cells produced at the GF will be the new cells for the GIII series (TM3/Y). That's why the TM3 is totally depended on the GF.

Can't you lay them flat???

 

[brianman]

Well of course a bigger battery will take longer to charge also.

This is not necessarily true, IMO. Also, it's definitely not linear if true.

 

[Benz]

I'm not an engineer, automotive specialist, or anything close. However, since no one has burned anyone yet in this thread for offering an idea, I thought I'd throw this one out and see what real engineers think:

I'm old enough to remember 2- and 3-speed transmissions. Now there are 7-, 8- and 9-speed ones, not to mention CVT's. Presumably the major reason for the shift (pun intended) to more and higher gear ratios in ICE cars has been to improve MPG and by logical extension Range. Might TM be reconsidering its use of a single-speed differential and possibly exploring something like a continuously variable diff (CVD) or multi-speed one (again I think), with the aim of reducing energy use at higher speeds while still providing high torque at lower speeds?

That is a good question.

I remember having read a while ago an article about an English or Italian company that would supply (automatic?) gearboxes only for EV's.

In the coming years there will be some breakthroughs in this area, I think. And that shall improve the range of EV's. Innovation doesn't stop.

 

[Model 3]

Can't you lay them flat???

Not sure... I'm thinking of the fire-safety of the pack. It's constructed to send the gas/flames down in case of fire, not sure it's possible when the cells lay flat?

 

[Tasdevil]

Can't you lay them flat???

Not if you want the length and width of the pack to be smaller

 

[TonyWilliams]

The cell dimensions could change from 18 mm radius/650 mm length. Elon and JB said on the Q2 call that their own modeling had shown the optimal size to be about 10% larger on both measures, yielding about 30% more volume per cell. I'm sure they'll find a way to stack these in a battery pack of today's Model S size.

If they go with larger format cells for Gen 3 they'll of course build the pack around that cell's dimensions.

But, they also said that this slight size increase would only yield a 15% improvement. Assuming it can be packaged in exactly the same footprint as the 85kWh one, I guess that gives us nearly 100kWh.

 

[richkae]

That is a good question.

I remember having read a while ago an article about an English or Italian company that would supply (automatic?) gearboxes only for EV's.

In the coming years there will be some breakthroughs in this area, I think. And that shall improve the range of EV's. Innovation doesn't stop.

A transmission will do nothing to help the range of an EV.
The motor in the Model S probably varies between 90 and 95% efficiency in the normal operating speeds.
Automatic transmissions introduce loss, from the few searches I have done, this loss is in the 5-6% range.
Adding a transmission will most likely only reduce overall efficiency.
The power electronics that control an AC motor are also in the 90-95% efficiency ballpark. There is only tiny room for improvement in the motor or controller.

The way to increase the range of an EV with the same amount of stored energy is by reducing drag.
You reduce tire drag by making the car lighter and the tires smaller. You reduce aero drag by making the car more aerodynamic or smaller so that it has smaller frontal area.

 

[brianman]

But, they also said that this slight size increase would only yield a 15% improvement. Assuming it can be packaged in exactly the same footprint as the 85kWh one, I guess that gives us nearly 100kWh.

Math check:
85kWh * (100% + 15%) = 97.75 kWh

You did say "nearly" but that's a bit too much rounding up for my taste.

- - - Updated - - -

The way to increase the range of an EV with the same amount of stored energy is by reducing drag.
You reduce tire drag by making the car lighter and the tires smaller. You reduce aero drag by making the car more aerodynamic or smaller so that it has smaller frontal area.

It's a little "out there" but...
Has there been any exploration in the automotive realm to -- via some mechanism -- effectively extend the vehicle's front area to a point more forward than the actual length of the vehicle. I'm sure I described it poorly but perhaps someone can translate.

 

[J1mbo]

JB also mentioned chemistry changes which gave around 10% more ED. With the repackaging of the cells, that makes a 100kwh pack possible in a slightly bigger format than the current Model S pack.

 

[MacroP]

I'm thinking (out loud) once the GF is up and running they may switch to the 26650 format - which is still a standard size. The 40% increase in diameter doubles the cell volume hence doubles the capacity of each cell - even if the ED/chemistry remains the same for some time (which I doubt). This should help reduce the assembly cost at least though the overall assembled battery capacity would remain the same. A 7000+ cell battery must take a huge amount to resources to assemble - the automatic spot welding machine would be doing overtime on the interconnecting plates. I guess the GF will give them this flexibility to adapt more easily - even taller cells perhaps for future cars with greater ground clearance which may allow a slightly thicker battery.

 

[ElSupreme]

I'm not an engineer, automotive specialist, or anything close. However, since no one has burned anyone yet in this thread for offering an idea, I thought I'd throw this one out and see what real engineers think:

I'm old enough to remember 2- and 3-speed transmissions. Now there are 7-, 8- and 9-speed ones, not to mention CVT's. Presumably the major reason for the shift (pun intended) to more and higher gear ratios in ICE cars has been to improve MPG and by logical extension Range. Might TM be reconsidering its use of a single-speed differential and possibly exploring something like a continuously variable diff (CVD) or multi-speed one (again I think), with the aim of reducing energy use at higher speeds while still providing high torque at lower speeds?

Electric motors are very efficient. And their efficiency is very consistent throughout its whole RPM range. Combustion engines are not uniformly efficient, in general they are much more efficient at low rps. So having a multi speed transmission (despite adding losses) keeps the ICE in it's efficient band, and there is enough change in the ICE efficency to pay the transmission penalty.

EVs the motor efficiency doesn't vary enough to pay a small penalty going through a transmission.


Now a gearbox could add some top speed to the vehicle, but that has nothing to do with efficiency. And driving 130 in a street car is more than adequate.

 

[brianman]

Now a gearbox could add some top speed to the vehicle, but that has nothing to do with efficiency. And driving 130 in a street car is more than adequate.

... as long as speed limits cap out at something significantly lower than that like 85mph, for sure.

 

[Ampster]

........... Might TM be reconsidering its use of a single-speed differential and possibly exploring something like a continuously variable diff (CVD) or multi-speed one (again I think), with the aim of reducing energy use at higher speeds while still providing high torque at lower speeds?

Anything is possible but remember they started out with a two speed Roadster and concluded that a single speed was better. Others have pointed out numerous reasons. The analogy to an ICE is flawed based on fairly flat torque curve and RPM range of AC induction motor. AFAIK the diesel electric train and many urban electric public transportation are single speed.