Are Larger Format Cells In The Works For Tesla’s Trucks & Power Packs?

NOV 19 2018 BY GEORGE BOWER 35

A larger format, low C rate battery would significantly cut costs, and weight.

Maybe Tesla’s new “Megapack” fits into the puzzle as well?

We just published an article on the Tesla Pickup Truck and in that article estimated the pickup’s battery size at 200 kWh’s and its motors at 600 HP (447 kw), for a paltry C rate of only 2.2; much lower than Tesla’s sedans.

The Tesla SEMI truck also has a low C rate. Our analysis of the semi truck had four Model 3 motors for a total of 1080 HP (805 kw) and 900-kWh battery, putting the C rate for the SEMI truck at only around 1. Both the pickup truck AND the semi truck have low C rate (power) batteries.

Here’s a figure that shows the effect of format size and electrode thickness on cost (ref):

Effect of cathode thickness and battery size on cell costs

The graph shows the effect of electrode thickness (C rate) and battery size on cost and it shows a huge effect on costs in the neighborhood of 20%. Thicker electrode coating gives us lower C rates just like in the semi and pickup.

We have the semi and the pickup that could live with a lower C rate, larger format battery. We also have Tesla’s new, secretive “Megapack” for huge power pack projects (ref) and it turns out that power pack installations also have a low C rate (ref).  In our opinion, it justifies a new line of batteries for the Gigafactory=larger format, low C rate batteries.

Big win in the cost, weight and energy density departments.

I know it’s a bit far-flung to predict another increase in format size. We’re pretty close to production on the semi. A bit late to be starting on a new battery design but Tesla’s future battery designs are a closely held secret just like the “Megapack.” Could be that they have a large format low C rate design already in development?

A long shot for sure but interesting food for thought nonetheless.

Categories: Battery Tech, Tesla

Tags: , , ,

Leave a Reply

35 Comments on "Are Larger Format Cells In The Works For Tesla’s Trucks & Power Packs?"

newest oldest most voted

We don’t know what it’s going to be until it is unveiled. Interesting speculation, but too soon to matter.

Interesting, but wouldn’t that negatively affect charging rates?
A pickup towing a camper trailer will likely have less range than a sedan with a much smaller battery, and the worst time to wait while charging is when it’s delaying a campfire and beer!

Thanks for this, but OMG, this is very bad news 🙁

A Model X 100D is rated at 295 miles but towing an ultralite travel trailer drops that to about 110? That’s only 37% of the range!!!

The best case was the lobster trailer (usually quite small and areodynamic), and it still lost more than 1/3 of it’s range?

And this is at 50mph. Ouch. Please say it ain’t so.

Hence why 300kWh battery packs are going to be a requirement for most cowing towing consumer vehicles (5th wheelers and large trailer towers). 600 miles of range could end up as 200 miles. Then take in to account cold weather… (although admittedly most consumers would only be towing during the summer).

The Tesla pickup may have a monster battery pack (200 kWh is too low in my estimation). Musk said 400-500 miles and “maybe more.” 300 kWh would get you 300 miles towing something heavy with poor aerodynamics, like a travel trailer. They will also need a monster pack to ensure they can maintain the large continuous power demamd of towing 10,000 lbs up a six degree incline at highway speed. If they can get pack cost to $80/kWh by the time the truck launches a 300 kWh pack would cost them $24,000, so it seems feasible.

Just in – more specs on Rivian’s pickup (180kWh = 400+ miles of range, unlaiden I assume )

Quoted, not my words:
“Rivian’s largest battery pack holds a staggering 180kWh of energy and delivers 400+ miles of range. Additionally, Rivian will offer 105kWh and 135kWh configurations, with a starting price just over $60K. The top of the line battery pack will start just under $90K and will deliver close to 800hp.”

400+ miles on 180 kWh requires a Ridgeline-like body. Hope they do well with it.

The problem is less to do with the weight you are towing and more to do with what you are towing. Notice on the chart a 700kg horse trailer reduces range to 116 miles, while a car which is 2,250kg aka, over 3X heavier puts range at 137 miles.

Aka, the aerodynamics is what matters the most, not if it is light or heavy.

I will also note the data comes from Bjorn who is located in Norway, so more than likely cold weather.

Weight matters more than aerodynamics when climbing the long 6% highway grade Joe described.

Norway is warm in summer, like anywhere else. It’s only when you get to <0c that temperature starts to matter. Not California warm, but it's climate is not dissimilar to the East coast of the US (including winter).

The Norway point is relevant though. Those towing ratings were for European trailers/horse boxes/caravans, which are a lot smaller and more aerodynamic than most trailers towed in North America… What's the difference in aerodynamics between a large European caravan:

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTCDSSRz4EOU91oOWxExSPqQ4NshqmdPpBcOVBBgh7nuzoK9T-v

and a mid size North American "Caravan"

http://images.dsscars.com/dealerpicsnew/1/1/4/3/1143_V201306151616302.jpg?preset=

?

And what about the trailer with it’s own motor and battery?

I get down voted for preaching about towing in every pickup article, but the physics are daunting.

George’s 200 kWh pack might get 380 miles unladen, but only ~140 towing a camper at 65 mph. That’s about 80 miles between 20-80% fast charges. Who will pay $80+ thousand for that?

Tesla pickup is a very high end F-350ish truck with huge pack IMHO.

Towing (large trailers – with brakes) will have a heavy impact on power usage until trailers also get regenerative braking.

When the car brakes, the weight of the trailer will apply the brakes in the trailer automatically, hence there will be much less recouperationt of energy when going downhill or braking with a trailer attached.

Maybe we should get Ryan McCaffrey to bring tis topic to Musk during his upcoming intrview?
I hope someone could reach Ryan on Instagram or something..
(It might be a good idea to talk about the hitch option for model 3 as well?

For larger trucks with trailers, some manufacturers have made axels that can be fitted onto the trailer to give traction and be able to regen energy too.
I would guess something similar will come for smaller trailers suited for smaller vehicles like cars and pickup trucks. Unless the cost is prohibitive.

I’m even waiting for regen to be standard on most e-bikes. When you drive down a long hill and have to break a heavy e-bike with an adult person, there could be a good regen potential. Insted the bike eat break pads.

A 100 kWh charging at 100 kW is 1C. A 300 kWh pack charging at 300 kW is 1C.

I thought that the NCA chemistry was inherently limited- for thermal reasons- to smaller individual cells. The power pack is NMC chemistry because NMC has more tolerance of poor cooling and the power pack has no refrigerant mechanical cooling system, unlike the cars. No idea about the semi, but it would seem to be a weird switch to move the semi to NMC from NCA when they’ve managed to get cobalt in the NCA chemistry below 5% from the original 15%.

You’re right about NCA size limits, though I suppose chemistry tweaks might change that.

They dramatically reduced cobalt usage since the Roadster because that was LCO instead of NCA.

I think cycle life is the main reason they use NMC vs. NCA in Powerpacks. Semi also needs high cycle life.

Yes, I agree that lower C rate means longer charge time, so it’s a no go. I think Tesla and Panasonic are very committed to the 2170 format, and don’t expect to see a change any time in the next several years. However it is clear that there is on going changes in the chemistry, and that could include such things as thickness of various layers. Also don’t forget that solid state applies equally to cylindrical cells as rectangular, so it is entirely possible to make a 2170 solid state cell.

There is no telling as everyone also thought Tesla was 100 percent committed to the Tesla charging connector till a week ago when CCS was announced for the Model 3 in the EU…
It seems impossible to me for several 1,000 of the 2170 cells to be cheaper to build and assemble than several 100 of the large format auto batteries mass produced at the same scale…

The larger prismatic cells are more expensive. Cylindrical cells are the cheapest to produce per megajoule.

Yes, the pack takes more work with more small cells but if you have a good design and good robots you make it up there, as in high volumes fundamental cell cost is the #1 driver.

If you want to produce in low volumes with more hand wiring and assembly then larger prismatics are easier.

By definition your larger cells would NOT be produced at the same scale but an order of magnitude below the 2170.

You maybe, but it was pretty obvious they were going to have to change considering it was a legal requirement. It’s been mooted for months that they were going to change.

Lower C rate does not necessarily mean slower charging. A 100 kWh pack charging at 100 kW is 1C. A 300 kWh pack charging at 300 kW is 1C. A 500 kWh pack charging at 1000 kW is 2C. A 500 kWh pack charging at 50 kW is .1C

This article has an assumption that the maximum power output of the motors is the maximum power output and input of the battery.

What if the batteries could output and charge more but that would mean more expensive motor controller electronics, wiring, mechanical stresses, motor cooling loads that aren’t part of the market (or are reserved for the P up-spec option)?

But the general point is true that optimizing the particular cell design for the application is desirable—e.g. maximize energy for trucks, but for Roadster 2, maximize max power.

As long as it doesn’t look like that

I’ve Always Wondered Why they Didn’t Reduce The Number of Batteries By Utilizing the Larger C sized Batteries to Begin With . The C’s Pack More Punch With a Lesser Number Of Batteries, Could It Be Because the Little Laptop Batteries Were The Norm & Worked well In Computers as Well as Cars ? And Now , They’re Starting to Think Out Of The Box..

As I understand it, the decision on size was driven by thermal concerns. Smaller batteries are much easier to keep cool, the larger the diameter, the higher the temperature differential between the center and the outside where the cooling takes place. That’s why the 2170s are only 3mm more diameter (or more importantly only 1.5mm more radius) than the previous 1865s but 5mm longer which doesn’t aggravate the heat issue.

Oh, and don’t forget. This proposal for larger format batteries are the author’s and not from Tesla. There is no evidence Tesla is even considering this idea.

They should get rid of the whole packaging and use dielectric coolants like the german team did.They just have to find one that s cheap enough

or use edible seed oils

Thx. For that information . I also considered the Cooling Scenario, .However I did not realize that this was Only the authors suggestion & not a Tesla consideration ..That Changes Everything . I wonder What Tesla Really Has Up Their Battery Sleeve…. 🙂 …

C rate is not everything, every one knows that at max power the pack in sedan will quickly get overheated, but at normal driving or even highway driving you don’t need all that power. But imagine the pick-up at the same speed on a highway, it will probably need constant two times greater power output than sedan, to maintain the same speed, not to mention how much power you need for towing a trailor.

C-Rate is a result of how much heat a cell generates when being charged and discharged (low internal resistance). Larger packs are going to have more trouble getting the heat out, so they will still need a high C-Rate. The these big packs will also be charged in around the same amount of time, which wouldn’t be possible with lower C-Rate cells.

It is not necessary to change the format, the electrode thickness can be adjusted independently. Many suppliers offer the same format but optimized two ways, one for power (typically used for hybrids) and the other for energy (typically used for pure EVs in a larger pack). Not to disagree with your point however.