What Makes The Tesla Model 3 Battery Pack So Light?


It’s not just the new 2170 cells.

Major changes to the battery pack structure have been made as well.

The Tesla Model 3 pack weight (lb/kWh) is 15% lighter than the original Model S 85 kWh battery and

6% lighter than Tesla’s most advanced battery in the P100D.*

Of course, the new 2170 cells are a big part of the weight savings. Musk divulged that Tesla has quietly increased the nickel content of their cells which should decrease the weight of the pack.

See: Tesla Panasonic Quietly Outmaneuver All Lithium Battery Manufacturers

Also, the new 2170’s result in a smaller pack footprint because the cells are taller and this lowers the pack footprint and therefore the weight of the pack case. According to Jason Hughes, the Model S battery case is a whopping 275 lbs, which is over 20% of the pack weight so reducing the protective case weight is a big deal.

Major changes have been made to the Model 3 pack structure. These changes were revealed in an EVTV video we shared here on Inside Evs.

See: Watch As Tesla Model 3 Battery Is Removed And Disassembled

In this video, Jack Rickard spent over an hour disassembling the Model 3 pack. Lots of interesting things about the pack were discussed: some fairly common knowledge and some not.

Tesla has now consolidated all the power electronics into the pack itself. The AC charger and the DC-DC converter are now integral with the pack. In model S, these units were scattered about the car. Total wiring length has been drastically reduced, and here’s another interesting tidbit: Tesla has combined both the AC charger AND the DC-DC converter into one smaller and lighter unit (39:25 into the video).

All well and good but the structural changes were a bit more subtle and were not revealed until Jack removed the battery pack lid.

Photo courtesy EVTV

You can see in the screenshot that the lid is flexible and would offer little crash protection for the pack. Now the surprise. There are no sides on the battery pack. Other than the flimsy pack cover, the battery modules are completely exposed. That is totally opposite the Model S and Model X pack. In Model S, the battery case is thick and heavy to protect the cells and to provide rigidity to the car. The case in model S is solid metal ¼” thick.

The lack of sides is shown again in the screenshot below.

Also, notice the multiple attachment points of the modules to the case bottom. The modules themselves are adding rigidity to the pack as well.

What do we conclude from the fact that there are no sides to the pack? Has Tesla moved crash protection from the battery case to the body structure?

Consider the following figures from Tesla’s emergency response guide.

In the Model S, the heavy battery case provides the crash protection for the battery with minimal high strength steel.

Photo courtesy Tesla emergency response guide

Now check out Model 3. Lots of high strength steel around the pack.

Has Tesla transferred case structure weight and battery protection from the battery case (Model S) to the body? This makes total sense because Tesla has to transport completed battery packs from the Gigafactory in Nevada to the assembly plant in Fremont. There’s less weight to haul.

Makes sense to us.

What do you think? Maybe the flammability issues with Tesla’s battery have been dealt with in another way?  Perhaps the intumescent goo been resurrected? Let us know in the comment section.

*P100D and Model S85 pack weights adjusted upwards to include AC charger and DC-DC converter since M3 pack weight includes those items.

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37 Comments on "What Makes The Tesla Model 3 Battery Pack So Light?"

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Can you please quote metric measurements as well, most of the world do not understand lb’s or inches.

Google is not your friend anymore???? 😱😳

that is not the point.
It is bad enough that reagan stopped America’s move to metric, but to go back/forth with measurements gets old.
I have to say that I wish that global read, American-based media would adopt metric and then have Americans google for it or at least get used to metric.
Other than a few measurements, metric is superior.

Yea, inches are really stupid unit. After all, everyone has different size of theirs inch (or foot). Not to mention it scales really bad.

There is a definite tendency to over estimate a 6″ measurement to 8″, that’s for sure.

Sorry @robert – 150mm to 200mm….. 🙂

152.4 to 203.2

Agreed. The standard in the USA is to provide both where foreign consumption of the data is indicated.

See how silly the imperial system is, this is why only 3 / 193 countries still use it. (Third world Liberia, Myanmar and … U.S.)

Which is funny, since Tesla strictly uses the metric system except when absolutely forced to SAE for legacy items.

And while we’re at this subject….

Let’s drop hp’s for motor power and go strictly with kW. Ok?

esp since this is electric.

OK, but 1 person, the author alone could prevent 50-100 people from doing the same numerous calculations independently.

Is it a big request for your non-Anglo Saxon readership?

I live in an Si unit country and I have no problems converting lb to kg and inches to meters. Calculator is not needed. 1 lb is approximately 0.5 kg and 1 inch is 2.5 cm. Not hard calculations! This precision is often enough.

1 lb. = 0.5 kg is a pretty low precision. I prefer 1 kg = 2.2 lbs, or 22 lbs = 10 kg.

Great article as always George! Wonder how the dimensions will change for the smaller pack?

On first look I would say the $35k Model 3 will use both the smaller (23 cell) outside packs an just one (25 cell) center pack. That would give it about 55 KwH and save around 207 pounds (94 kg).

Not that I am interested in doing so, but is the pack designed to be swapped like the Model S? The only way I would ever give into the battery swap is if I had a way to secure my own battery without it being used and abused by someone else.

It’s not designed for battery swapping.

No loss. At all.

Right. Tesla’s experiment with Model S battery swapping showed that very few Tesla car owners are interested in swapping. Most of those who tried it once, never did so again.

No, it’s pretty integrated into the car; not good for a quick swap. They spoke of this earlier in the video, how much they had to disassemble just to get the pack out.

Hot air.

I think passenger cabin must be protected, and I think that’s done with Aluminum with S. 3 uses more steel for passenger cabin. If 3 has as much Al as S, I think 3 would be lighter.

Love the articles by George Bower. IEV should kick his ass to write more.

Yes, great stuff!

Primary reason for going to steel is lower cost.

George, i’m wondering if the Model S/X packs were also originally setup with swapping in mind, which didn’t pan out. So the Model 3 design had more freedom for weight reduction, etc.

A bigger question to ask here is how will the new chemistry affect the battery longevity and degradation? The S looks to have a stelar longevity and really low degradation but we can’t assume that will happen for TM3, can we?

Musk has said that the longevity is better in the Model 3.

Fiddling with the battery chemistry is something battery makers are always doing. I hope we can trust Panasonic to do accelerated age testing, to make sure that newer chemistry mixes won’t lead to shorter battery life.

Of course, we can’t always depend on EV makers to do the right thing. Look at Nissan; apparently the newer batteries in the Leaf age even faster than the older ones?!?!

But Tesla isn’t Nissan… thank goodness!

Well, when you no longer design the pack for swap, then some of the pack structures won’t be needed.

The going away from battery swap will be sure to optimize the design for lighter weight. one less trade off to make.

Ol’ whatshisnuts said the model 3 body was the heaviest and most expensive that he’d ever seen. He also said there were areas of higher strength steel that he could not explain … so I wonder if that’s all related? … but you’d think he (Monroe), if anybody, would recognize if they (Tesla) are shifting battery protection from the battery case to the body.

On the battery goo, … does that mean nobody is ever going to try and open up a module to repair, or replace cells? (Has Tesla opened up battery modules on previous (non-gooey) modules for repair, cell replacement/ refurb a pack?)

Also I wonder what the goo will do to recycle costs at end of life?

“…you’d think he (Monroe), if anybody, would recognize if they (Tesla) are shifting battery protection from the battery case to the body.” It’s “Munro”, but yes, you’d think so. Certainly Munro presents himself as an expert in the field. But from many, many comments about Munro’s analysis, it looks like that while he may know gasmobiles, he certainly doesn’t know BEVs! I’m no expert by any means, but from what others have said, it looks like Munro doesn’t have a clue about EV powertrains, nor the electronics found in modern electric cars, and did not understand that the Model 3 needs a stronger frame than a normal car has, to hold its heavy battery pack. “…does that mean nobody is ever going to try and open up a module to repair, or replace cells?” It’s probably an exercise in futility. Cells in a li-ion battery pack have to be very carefully matched, so the cells will all age (and lose capacity) at the same rate. Trying to replace individual cells will likely unbalance the pack and cause the entire thing to prematurely age or lose significant capacity. To avoid that, you’d have to replace them with very carefully matched cells,… Read more »

Monro has done the BMW i3 and Chevy Bolt EV among others. Even if he doesn’t specifically know all the terms, he has people that do.

Significant improvement in battery packing, nickel content increase, frame strengthening and so on.
Great job Tesla.

“In Model S, the battery case is thick and heavy to protect the cells and to provide rigidity to the car.”

Yeah, in Tesla’s previous cars, the battery pack case was heavy and thick, designed to add structural rigidity to the car. I was wondering if Tesla would throw that concept out with the Model 3, because it seems like it would be more weight-efficient to add structural strength to the car’s frame or unibody, rather than the battery pack casing. In that case, Tesla would want to make the battery pack case as light as possible.

Looks like I was right about that! 🙂

Go Tesla!

Great job, George. As usual, a thought-provoking and intellectually stimulating read. It’s the pack. The pack. The pack! Study of the evolution of the modern electric car is fascinating and everything starts with the batteries and how they are packaged. Your assumptions seem sound. Surely considerations of transport, materials and manufacturing costs all played a part during the planning if the 3 and the Y. Just like the evolution of the ICE-powered vehicle, many varied solutions will appear, the most practical and effective ones will survive and morph into more affordable, strong and reliable electric storage and drive systems. Tesla is paving the way. From the start, mistakes made in every stage in S and X were considered. Going from a small batch, high priced consumer good to a moderately priced, mass produced good in the 3 requires so many adjustments in mentality. It’s exciting to see changes accelerated through software updates. Something heretofore unproven in the auto business on the massive scale. Tesla is achieving. No longer is a car static after purchase, immediately declining in value and versatility as days and years pass by. To me, this is one of the most exciting aspects of Tesla…. Forging a… Read more »