Powering the Tesla Model 3: Why the 2170 EV Battery Cell Will Give Tesla a Prolonged Edge

2170 battery tesla model 3

We recently covered the story of how a Vancouver Model 3 owner did more than 322 miles in his long-range Tesla Model 3 and still had power to spare even though he was only charged to 83% before that leg of his trip. The question we’re going to explore here is this: how is it possible that a battery with a maximum range of 310 miles was able to do 322 miles without breaking a sweat – Literally, at least for the passengers, because they had the air conditioning on the whole time. How did that happen? Was it an anomaly?

Tesla Model 3 Does 322 Miles with the Air Conditioning On, and Power to Spare

To answer that, we have to look at the rated range versus actual range of a Model 3 – and why its 2170 cells play a huge part in that.

EPA and Other Ratings vs. Real-World Model 3 Range

First of all, the 310 miles advertised by Tesla for the Model 3 is an EPA rating, not the maximum range. The real-world range for the long-range version Model 3 varies wildly. While some reported getting less than 310 miles under actual driving conditions, “hypermilers” have literally gone the distance at beyond, with the current record for Model 3 hypermiling being 622 miles, albeit unmanned and on Autopilot on a closed circuit. Watch the video of the hypermiling run below:

An earlier record of 606 miles was accomplished in live road conditions.

Of course, hypermiling involves cutting down power usage by turning off the air conditioning, using standard tires, removing any extra fittings and so on. So those aren’t real-world ranges. However, it does show that a real-world range beyond 310 miles is not an impossibility.

As a matter of fact, here’s a very painstakingly developed table of ranges for various Tesla Models including the Model 3 LR (the type that achieved the 322-mile run.) This was posted on the Model 3 Owners Club forum, and Troy, who put this together, deserves a hat tip. We’ve also pasted Troy’s explanation for using the EPA highway dyno score for this table:

As you can see, the Model 3 LR with 19″ wheels only got 424 miles in this test, while the the variant with the 18″ wheels got 474 miles and 454 miles with and without the aero covers, respectively.

Again, these aren’t real-world numbers but they show the possibility of higher range than 310 miles under certain conditions. The EPA range as arrived at by Troy from the EPA highway dyno scores is as follows:

“EPA rated range = 0.7 *

In the formula, the 0.7 multiplier is needed because the EPA dyno tests are performed at low speed. The city test is performed at 21 mph and the highway test at 48 mph average speed. This results in unrealistically high range numbers. Therefore they apply the multiplier to convert the numbers to more realistic numbers. So far, all EV manufacturers have used the 0.7 multiplier except Tesla. Tesla actually uses 0.7 too but only for the Model 3.

Converting EPA highway dyno scores to range numbers
I have used more realistic multipliers to adjust EPA highway dyno scores until they matched the following numbers:

Model S 75D: 265 miles at 65 mph
Model X 90D: 260 miles at 65 mph
Model 3 LR: 350 miles at 65 mph.Tested by Consumer Reports. Source: article

350 miles is the range that Consumer Reports got when testing the Model 3 LR. In that particular case, the standard level of regenerative braking was applied, which is actually higher than what Consumer Reports typically uses.

We have to keep in mind that there are several factors impacting real-world range as opposed to EPA-rated range or ranges based on other test conditions, and these are as follows:

  1. Tire type and presence/absence of aero covers on the 18″ wheels vs. upgraded non-standard 19″ wheels

  2. Any extras that may add to the weight of the car – the drop in range because of this factor is clearly seen in the Dual Motor and Performance variants of the Model 3, which have lower ranges that are closer to the 310-mile EPA-rated range

  3. Actual ratio of city vs. highway driving – includes start/stop driving, highway speed variations, frequency of rapid accelerations, braking frequency, etc.

  4. Regen braking level – Model 3 owners typically have this set to standard, which is considered ‘high’ by Consumer Reports

  5. Other factors such as gradient changes, road type, on-board electronics usage, the weather (can affect the batteries), etc.

All of these things either give or take away from the real-world range of the Tesla Model 3. But now let’s discuss the “thing” that gives the Model 3 this much range in the first place – range that is second to no other EV sedan in the world.

The 2170 Cell Used in Model 3

The 2170 cell format (also called 21700) is different from the older 18650 cells that Tesla and Panasonic are using in Model S and Model X. The names come from the dimensions of each cell – 21mm X 70mm vs. 18mm X 65mm.

Image result for 2170 and 18650 cells tesla panasonic

As you can see, the 2170 cells are larger, but that’s not all. They also have a higher energy density, not only over the 18650 cell format but, per Tesla, they are “the highest energy density cells used in any electric vehicle.” According to Tesla’s letter to shareholders after Q1 results:

“The Model 3 battery has sophisticated power electronics, cooling systems and structure that enables high level of safety, sports-car like acceleration, Supercharging, a 120,000 mile warranty and low cost. Cells used in Model 3 are the highest energy density cells used in any electric vehicle. We have achieved this by significantly reducing cobalt content per battery pack while increasing nickel content and still maintaining superior thermal stability. The cobalt content of our Nickel-Cobalt-Aluminum cathode chemistry is already lower than next-generation cathodes that will be made by other cell producers with a Nickel-Manganese-Cobalt ratio of 8:1:1. As a result, even with its battery, the gross weight of Model 3 is on par with its gasoline-powered counterparts.”

Tesla is already using less than 10% cobalt. We know this because the NMC 811 cell chemistry uses 10% (80% nickel, 10% manganese, 10% cobalt, hence NMC 811), and Tesla says their battery has lower cobalt content. For its part, Panasonic is figuring out a way to eliminate cobalt altogether. According to Kenji Tamura, head of Panasonic’s automotive battery division:

“We have already cut down cobalt usage substantially.

“We are aiming to achieve zero usage in the near future, and development is underway.”

And this is where the 5-year edge will come from. If Panasonic does achieve its goal, Tesla may already have dibs on a long-term contract. And Panasonic isn’t going to pass it up because the Model 3 has already paved the way for mass-market EVs that can rival any ICE (internal combustion engine) car on the market. The Roadster (2020) will be, as Musk said, the final smackdown to all gasoline cars, but the Model 3 is the real hero. And powering that hero is the humble 2170 cell that does its job exceedingly well behind the scenes.

In the years to come, new cathode chemistries, new fuels and new powertrains could help other companies usurp Tesla’s EV battery crown. But development cycles being so long for such projects, it’s not very likely that a rival technology will upend the Tesla-Panasonic dominance for another half-decade, at the very least.