Tesla May Soon Have a Battery That Can Last a Million Miles.
Wired.com Sept. 23rd, 2019
Last April, Elon Musk promised that Tesla would soon be able to power its electric cars for more than 1 million miles over the course of their lifespan… That’s more than double the mileage Tesla owners can expect to get out of their car’s current battery packs…
Earlier this month, a group of battery researchers at Dalhousie University, which has an exclusive agreement with Tesla, published a paper in The Journal of the Electrochemical Society describing a lithium-ion battery that “should be able to power an electric vehicle for over 1 million miles” while losing less than 10 percent of its energy capacity during its lifetime.
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The energy density of a lithium-ion battery is one of the most important qualities in consumer electric cars like Tesla’s Model 3. Customers want to be able to drive long distances on a single charge. Tesla’s newer cars can get up to 370 miles per charge, which is well beyond the range of electric vehicles from other companies.
Getting a million miles lifespan
There are 3 ways to achieve it:
- double the battery capacity
- double the battery density
- double the cycle life
1/ Double the Battery Capacity
Battery cost may be less of a problem, but there may not be enough space to fit all the batteries.
2/ Double the Battery Density
Increasing the battery density will reduce the maximum discharge and charging current rating and will affect the performance of Telsa as a sports car.
Generally speaking, there’s a trade-off between energy density and battery lifetime—if you want more of one, you get less of the other. Wired.com
3/ Double the Cycle Life
The battery pack needs a minimum of 2,700 life cycles to achieve 1 million miles as each charge can get up to 370 miles. This is double the current performance, therefore, the cycle life is about 1,350 currently.
It really takes a technology breakthrough to double the life cycles which may not be possible, limited by the law of Physics.
However, there is a workaround!
In general, according to the data from one of a leading manufacturer of Lithium-ion batteries. Depth of discharge (D.O.D) affects the cycle life. Detail calculator
| D.O.D | Cycle Life | Cycle Life |
| Improvement | ||
| 90% | 3000 | 0% |
| 80% | 5000 | 67% |
| 70% | 7000 | 133% |
If Telsa’s 370 miles per charge is based on 90% D.O.D, simply reducing it to 70% D.O.D, the cycle life will be improved by 133%.
In order to achieve 370 miles per charge at 70% D.O.D, the battery capacity required to increase by about 28.5% only.
Conclusion
A million miles goal can be achieved simply by increasing the battery capacity or size by no more than 28.5%
Whether you want to do fast charging, long-lasting, or high energy density, they are just marketing gimmick. The law of Physics for Lithium-ion battery can never be changed!
The author has 30 years of experience in the Lithium-ion battery industry from the laptop application, electric vehicle, to large energy storage.
To learn more about Lithium-ion batteries, please visit everspring.net