by kublikhan » Fri 27 Sep 2024, 21:48:56
I've been seeing some posts from Lucky suggesting EV batteries die at 8 years. The report below suggests the battery on your average new EV will still have over 80% SOH at 12 years. It also reports this is an improvement from their last report 5 years ago as the rate of battery degradation has slowed down with the newer EVs/batteries. This implies new EVs are getting better at slowing down battery degradation vs older EVs. Good to know the tech is getting better over time.
$this->bbcode_second_pass_quote('', 'S')eptember 3, 2024 - A lot has changed in the world of electric vehicles over the past five years. When we analyzed EV battery health (and published the original results in this blog post) in 2019, we found EV batteries degraded, on average, at 2.3% per year. Of course, some EVs performed better and others less well, but the average was surprisingly good. In 2024, we performed a new analysis and the results indicate that EV batteries have improved significantly, degrading at 1.8% per year on average.
How often do EV batteries need to be replaced?
According to our data, the simple answer is that the vast majority of batteries will outlast the usable life of the vehicle and will never need to be replaced. If an average EV battery degrades at 1.8% per year, it will still have over 80% state of health after 12 years, generally beyond the usual life of a fleet vehicle.
That’s the simple answer, but the question of how long does an electric car battery last is complicated and numerous factors determine EV battery longevity.
Common factors impacting electric car battery life
In general, today’s battery electric vehicles (BEV) and plug-in hybrid electric vehicles (PHEV) use lithium-ion batteries. Several key factors determine how long lithium vehicle batteries last and the rate at which their range declines. These include:
* Age
* Temperature
* Operating state of charge
* AC vs DC charging
* Usage (energy cycles)
* Battery chemistry
* Battery system and thermal management components
How does temperature affect EV battery life?
As illustrated below in figure 3, vehicles driven in hot climates showed a notably faster rate of decline than those driven in moderate climates. This is not great news if you and your fleet toil under the hot sun but keep reading for best practices to reduce the impact of heat on your fleet.
How do vehicle make, model and year affect battery performance?
Our data shows that vehicle batteries respond differently to the test of time, depending on their make and model year. Why do some vehicle models, on average, degrade faster than others? Two potential contributors are battery chemistry and the thermal management of the battery pack.
Liquid cooling vs air cooling: which is better for EV battery longevity?
Let’s compare a vehicle with a liquid cooling system to one with a passive air cooling system: the 2015 Tesla Model S and the 2015 Nissan Leaf, respectively. The Leaf has an average degradation rate of 4.2%, while the Model S is 2.3%. Based on this comparison, good thermal management offers better protection against battery degradation.
How do charging methods affect battery health?
The use of DCFC equipment[Fast Charge] does appear to significantly impact the rate at which batteries degrade. Rapidly charging a battery means high currents, resulting in high temperatures, both of which strain batteries. In fact, many automakers suggest drivers and fleet managers limit the use of DC fast charging to prolong their electric vehicles’ battery life.
State of charge, charging buffers and their impact on EV battery lifespan
The Chevrolet Volt (now discontinued) had comparatively large top and bottom protection buffers (regions A and D above) that dynamically changed as the battery aged. While the larger buffers meant less energy for driving, it resulted in a longer-lasting battery pack. Given the larger SOC buffers, liquid thermal management and dynamic (decreasing) buffer size, Volt users could expect slower-than-average degradation rates, and our data bear this out (as shown in figure 9 below).
Conclusion: Operators can be confident that EV batteries will last as long as they need them
While EV batteries degrade at different rates depending on model and external conditions, our data indicate that most electric vehicles today have not experienced a significant decline in battery life. In 2019, we assessed the average EV battery degradation rate at 2.3% per year and the rate under ideal climate and charging conditions at an impressive 1.6%. In our most recent research, including many newer models, we found an average rate of 1.8% and the best performers declined only 1% per year or less.
So, how long do electric car batteries last? Numerous factors determine an electric vehicle battery’s lifespan, but on average, EV batteries will outlast the useful life of their vehicle, especially if drivers follow charging and driving best practices.
How long do electric car batteries last?If that part about the battery buffers is confusing, let me try to explain it better. No EV maker allows their battery to be charged/discharged to 100%. They limit the maximum amount you can charge and discharge in order to prolong battery life. And it works. But no matter how clever they get with their battery protection methods, the battery will degrade overtime. So The Volt did something clever to counteract that. It started with larger than normal buffers, so the battery would degrade more slowly. Then as the battery aged, the size of the buffers would slowly shrink. Thus the useable portion of the battery was degrading more slowly than the total battery capacity. This is similar to what hard drives do. All hard drives have a "spare sector pool". In the normal use of a hard drive, it will occasionally develop bad sectors. When the hard drive detects a bad sector, the sector gets marked bad, removing it from the useable sectors, and a replacement is brought in from the spare sector pool. All of that is invisible to the user and happens in the background.
The oil barrel is half-full.