Why Are Batteries So Confusing In An EV? Making Sense of Tesla EV Batteries
EV Batteries and Tesla
It can be confusing trying to understand the batteries in an EV and, in particular, Tesla EV's. To start answering this question, we will look at Tesla's first mass-produced vehicles, the Model S and Model X.
Each of these vehicles have a battery that is around 100 kWh of Energy and gets around 3 to 4 miles per kW. Right away, this measurement is different from what you would see for a gas car. For a gas car, you would have, say, a 20 gallon tank and a measurement of, say, 20 miles per gallon.
Since 2012, Tesla has stuck with 1865 battery cells. This means the dimensions of each battery cell in the battery pack that powers the vehicle. It's 18 millimeters across and 65 millimeters down. You can fit thousands of these cells in a batter pack on the bottom of the car. Tesla continues to use these cells because they are very performant cells - they are Energy dense and that is needed when you need a car to go fast. Many smaller cells giving Energy at once gives you more power for the power train of an EV, causing faster acceleration.
Tesla also uses 2170 cells. This is 21 millimeters across and 70 millimeters tall. This battery cell is a little bit bigger. These cells got put in the Model 3 and Model Y originally. These cells are more optimized for mass production because the 3 and Y are much more mass-produced than the Model S and Model X. These cells seem to be the most plentiful on the market as well, in an era where EVs are still in the beginning of the adoption curve.
There is a Model 3 RWD - the standard range, and it uses LFP batteries. These cells aren't cylindrical, they are prismatic - rectangle batteries that slide in the battery pack. This uses a different battery chemistry than the 1865 and 2170 cells. Those cells use an NMC chemistry, which stands for Nickel-Manganese-Cobalt. The LFP batteries instead use Lithium-Iron-Phosphate. Iron is more prevalent and the battery is less energy dense. LFP batteries are also less expensive and can charge to 100% with less degradation.
LFP batteries have a longer cycle life, which is good for the Model 3 RWD - standard range. You hit a cycle faster in a lower range vehicle. Tesla vehicles can get well over 250,000 miles and have degradation that isn't too bad - usually not more than 10% to 15%.
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Breaking Down Tesla EV Batteries
LFP batteries are nice in that they can be charged to 100% on a daily basis. The NMC batteries degrade faster when charged to 100%. Tesla makes this easy for you when you charge. An LFP battery vehicle will default to 100%. An NMC vehicle will default to 80%. You can still charge an NMC vehicle like a Model S or Model X to 100% for a road trip.
LFP batteries are less likely to catch fire, and an NMC battery is about 10 times less likely to catch fire than a gas car. LFP batteries also give the car the same amount of power at 5% to 10% state of charge, whereas an NMC battery loses some power at that percentage. This is because an LFP battery maintains a similar voltage regardless of the percentage remaining in the battery.
The recently announced Model 3 long range is in an unknown area. It only qualifies for $3,750 of the U.S. tax credit, which means the battery probably comes from overseas somewhere. Many speculate that the 325 Model 3 long range from 2023 will be a new LFP battery chemistry from CATL - that has a little bit of Manganese. This would give you a high cycle life with a higher range. But, we won't know for sure until the first versions of these are purchased.
The Model Y is Tesla's best-selling vehicle. It's got space, performance, affordability, dual-motors, and is built all across the world.
In the U.S., there is the performance and long range Model Y vehicles - these use the 2170 battery cells with an NMC battery pack.
The Model Y AWD has 279 miles of range and uses 4680 batteries. This is a new type of cell and is 46 millimeters across and 80 millimeters tall. Tesla makes these batteries and doesn't buy them from other companies. Tesla wants to make as many of these as they can in Fremont and Giga Texas. These cells can hold more energy, but they take more space. There is less construction time and connectivity needed for them. These cells and hold the vehicle together because they are big enough to act like a structure. Tesla saves money, complexity, and eliminates parts by doing this. These cells are NMC.
The Model Y from Giga Berlin is using the BYD blade battery, and these batteries are more thin and sharp - think rectangle batteries. Tesla hasn't made many of these types of batteries, and it will be interesting to see how much Tesla is saving using this battery. These are also LFP batteries and only sold in the Model Y AWD from Giga Berlin and seems more like an experiment right now.
Tesla hasn't told us what the Cybertruck will use, but I expect it to use 4680 NMC batteries that are part of the structure of the vehicle.
It can be confusing trying to understand battery chemistries, but hopefully this run down makes it easier to understand. Essentially, you have the battery chemistry and the size of the battery.
For more information, see this video from Tailosive EV:
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Jeremy Johnson is a Tesla investor and supporter. He first invested in Tesla in 2017 after years of following Elon Musk and admiring his work ethic and intelligence. Since then, he's become a Tesla bull, covering anything about Tesla he can find, while also dabbling in other electric vehicle companies. Jeremy covers Tesla developments at Torque News. You can follow him on Twitter or LinkedIn to stay in touch and follow his Tesla news coverage on Torque News.