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A Groundbreaking Study Debunking Battery Aging Myths: EV Batteries Are Actually Built to Last
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The adoption of EVs is growing globally, with nearly one in five cars sold in 2023 being electric. While electric vehicles continue to hit new records, there are concerns among people regarding the life of their batteries.
Battery technology is central to the EV revolution as it powers these vehicles and determines their charging speed, range, and overall performance. EVs typically use rechargeable lithium-ion batteries, which have high energy density and, as such, produce more power for their size.
The longevity of the battery, however, continues to be a key concern of consumers, besides range anxiety and charging time and infrastructure, regarding this technology that influences their perceptions. With consumer perceptions about the technology playing a key role in driving EV adoption, it's important to understand their concerns and expectations.
The thing is, social media and news articles contribute to shaping the perception of a high residual value loss of EVs due to battery aging.
With used EVs being described by the media as ”lying on the shelves like lead,” claiming that the rapid aging of the battery significantly reduces its range, this has led many consumers to view used EVs as unusable.
So, a new study took up the task of examining if the concerns regarding premature aging are actually justified. Also, to help alleviate the concerns, over 7,000 vehicles were analyzed to offer deep insights into battery life and vehicle residual value.
Conducted by AVILOO, a global leader in battery diagnostics for electric cars and plug-in hybrid vehicles, the study shows that EV batteries maintain a long service life even when used intensively.
While the lifespan of batteries varies by manufacturer and age, they can be expected to rival and even exceed the longevity of drivetrain components on internal combustion engine (ICE) vehicles.
The study found most batteries to be retaining more than 80% of their original capacity and, hence, usable far beyond the usual warranty period. Technological advancements are actually helping increase the performance and durability of the batteries, which can further be optimized by the user.
What Actually Determines a Battery's Longevity?
When looking into just what determines how long a battery's health lasts, the study found that it's their residual capacity that makes the decision.
Much like how, over time, things wear and tear and lose their potential, so do batteries. The capacity and efficiency of a battery are naturally reduced with time. This process is referred to as calendar aging, which is time-related, and cyclical aging, which is usage-related.
Calendar aging is the result of chemical structures within the battery cells changing over time, even if it is not actively used. Meanwhile, cyclical aging occurs due to the stress of repeated charging and discharging cycles.
Together, these two processes degrade the battery's state of health (SoH), negatively affecting both its energy storage capacity and overall performance.
SoH here is a key figure that reflects the degree of battery aging, but there's no standardized definition for it, with manufacturers using different calculation methods and following different goals. The study, meanwhile, used it to simply refer exclusively to battery capacity.
Now, just how severe is the battery aging in real-world conditions? To find the answer to this question, the study first used 50 vehicles from the P3 electric vehicle fleet to investigate battery aging by considering owners ‘ driving and charging behaviors to capture the variations between usage and manufacturers.
Then, Aviloo used data from more than 7,000 vehicles with up to 300,000 kilometers of mileage for a detailed quantitative analysis of battery aging in relation to mileage.
Unlike other studies, which utilized academic and laboratory data, this study made use of real vehicle data that allowed it to account for external influences. Aviloo, which performs battery diagnostics, has conducted over 60,000 capacity tests.
In these tests, the user connects the AVILOO Box to the vehicle's OBD interface and drives it until the battery goes down from 100% to 10%. Throughout this time, the Box continues to collect data and transmit it to the company servers in real-time, which then validate and analyze the data. This enables them to provide the SoH of the battery, which is calculated by comparing the current extractable energy to the energy available when the battery is new.
Battery Aging Happening at a Far Slower Pace Than Imagined
When it comes to electronics, consumers are always concerned about their batteries. How long do the devices last with a charge? Should they be charged all day long? There are many questions, and that's the same with EVs, which are expensive, more so than their ICE counterparts.
So, it makes sense that there are serious concerns among people about battery degradation in electric vehicles as well.
These concerns, however, are largely unfounded as the study revealed that the battery's capacity degradation is much slower than what has been assumed.
This degradation primarily happens in the initial stages. So, in the first 30,000 kilometers, the capacity degradation accelerates only for it to stabilize and then progress almost linearly. The observation of the field data confirms that the battery degradation in the later usage phases is substantially lower than in the initial phase.
As to what causes the initial capacity loss, it's the SEI layer (solid electrolyte interphase), which forms on the anode during the first charging and discharging cycles. When this layer starts forming, lithium gets converted into degradation products, which reduces the amount available for energy storage. Once this layer has stabilized, the loss of capacity slows down significantly, too.
According to the data, the majority of batteries had a SoH above 80% even after more than 200,000 km.
The data from the P3 fleet, which is based on heavily used 3-5-year-old vehicles, showed that nearly all of them had above 90% SOH. This “excellent performance” is maintained despite the fact that these vehicles are undergoing intense use in varying ways and have different manufacturers.
Overall, “field data indicate that, under real-world conditions, vehicles (especially those with high mileage) retain their actual capacity for a longer period,” stated the study.
Here's How Users Can Increase their Battery Life
While it's good to know that our EV batteries are really long-lasting, is there a way they can be improved? After all, we all want to know if there is something that we can do to improve the lifespan of the batteries of our electronic devices. And in the case of electric cars, we can certainly do so.
This study from Aviloo gives several pointers as to how EV owners can extend their battery life. One of the ways to achieve that is by addressing factors that cause calendar aging, aka time degradation. This involves parking the vehicle in moderate to low-temperature environments because excessive temperatures drive chemical reactions that accelerate capacity degradation.
When you have to leave your EV idle for prolonged periods, again, it's recommended to park it in a low to moderate state of charge, which is between 10% and 50%. This is because the state-of-charge (SoC) also affects the chemical processes in the battery. High voltages tend to quicken the aging of your vehicle's battery, especially during extended periods of inactivity.
Now, we will address the factors that affect cyclic aging, aka vehicle usage. For this, the study gives an ideal scenario for charging and discharging, which is to maintain a temperature within a moderate range of 20–50°C. Don't keep the temperature too high or too low when the vehicle is in use because both conditions expedite aging mechanisms such as increased lithium plating, SEI formation, and chemical structure breakdown.
Another way to improve battery life is not to engage in frequent fast charging. Occasionally, it is fine, and that has no serious effect on aging, but fast charging repeatedly affects it negatively.
Changing your charging behavior is another recommendation. So, instead of driving your EV completely empty and then recharging it to 100%, which increases the load within your batteries and ages it, what you should do is keep the depth of discharge low between 20% and 80%.
You may want to make some changes to your driving behavior as well; here, you refrain from taking long journeys at high speeds and strong acceleration as that causes high currents to flow, which then increases the temperature and puts more strain on the battery. So, adopt moderate driving behavior to slow down the battery aging of your electric car.
What About EV Manufacturers' Warranty?
The study from Aviloo, which covers 95% of all available EV brands, also looked into just how well the warranty from electric car manufacturers is working. The findings say they are actually doing a good job.
Continuous technological advancements and the growing experience of producers have actually allowed manufacturers to offer increasingly robust warranties, which assure a residual capacity of at least 70% up to a certain age or mileage, whichever is reached first. Below this threshold, the warranty covers repair measures to restore the capacity at the guaranteed level.
For EV battery systems, the current standard warranty is 8 years or 160,000 km, which is double the warranty consumers receive for the entire vehicle and other components. Some manufacturers, like Lexus, have even started offering extended warranties.
Aviloo's data revealed that manufacturers are offering increasingly extensive warranty conditions because SoH rarely ever falls below 70% during the warranty period.
The study further looked into the different phases of the battery battery's life cycle in terms of the warranty. The first one is End-of-Warranty (EoW), which is when the warranty ends due to the time elapsed or mileage threshold reached. Analysis shows that batteries can continue to be used beyond this.
The second one is End-of-First-Life (EoFL), which occurs well before the battery reaches 70% SoH and can be used in a second-life application. The third phase is End-of-Second-Life (EoSL), which is reached when the battery is no longer suitable for further use and must be recycled.
At Last, How Much Is Your Battery Worth After All the Use?
Now, what about the residual value of batteries? Is there any? The residual value, which is the estimated worth of the vehicle after it has been used for a certain period, is actually found to be high.
The residual value of the battery mostly depends on two factors — the current market price of EVs and the price of new batteries- and the condition of the used battery also plays a key role.
The loss of value in the warranty period primarily depends on battery aging and the remaining capacity, but once it expires, a greater loss in value is expected, states the study. So, the loss of residual value, as the study noted, is to be expected in each life cycle phase of the battery.
However, at the end of the first life, the battery may still have a significant value through a second use, depending on the cost of new batteries. However, once the EoFL is reached, the battery is tested for its suitability for a second-life application.
Even if a battery is severely aged, that doesn't mean a total economic loss after the first or second life, noted Aviloo. This is due to the fact that raw materials like lithium, nickel, and copper are still preserved. These valuable metals, as well as other materials, can actually be recovered during recycling. They can also be used in new batteries and continue to have an economic benefit.
So, the value of the used battery can be enhanced by reprocessing it until the battery reaches a minimum value that a recycling company will pay for, the state of its health notwithstanding.
Companies Leading the EV Sector
As EVs gain traction, car manufacturers around the world have been shifting their focus to electric vehicles. This includes General Motors (GM -0.95%), Lucid Group (LCID -0.46%), BMW, Ford (F -0.63%), Volkswagen, Volvo, and Rivian Automobile (RIVN -2.66%), which are all helping bring about this environmentally friendly change. Meanwhile, CATL, LG Energy Solution, Panasonic, QuantumScape (QS +0.84%), and Samsung SDI are heavily involved in manufacturing EV batteries. Now, we'll take a look at the most prominent names in these sectors:
#1. Tesla (TSLA +3.18%)
A leading EV manufacturer, Elon Musk's Tesla is also known for its battery technology and management systems. With a market cap of $1.069 trillion, TSLA shares are currently trading at $334.40, up 33.97% this year. It has an EPS (TTM) of 3.65 and a P/E (TTM) of 91.27.
Tesla, Inc. (TSLA +3.18%)
The incoming US administration actually paints a bullish picture for Tesla stocks as Musk has been a central figure in pushing for President-elect Donald Trump's return to the White House. The tech billionaire was recently picked by Trump, along with former Republican presidential candidate Vivek Ramaswamy, to lead the newly-created Department of Government Efficiency (DOGE).
As for its financials, the American carmaker reported a net profit of $2.18 billion in Q3 of 2024, an increase of 16.2% from a year ago, exceeding its Chinese counterpart BYD's profit, which increased by 11.5% during the same period to 11.6 billion yuan ($1.6 bln). Tesla's profit margins, however, were bolstered by automotive regulatory credit revenue, coming in at $739 million during the quarter. Tesla's year-to-date sales, meanwhile, were $71.98 billion. For the quarter, Tesla reported 462,890 vehicle deliveries, and for next year, the company's goal is to launch more affordable models.
2. BYD (BYDDY: OTCPK)
BYD is a major Chinese company that produces EVs and lithium-ion batteries for its own vehicles and other vehicles. With a market cap of $111.79 billion, BYD shares are currently trading at $66.68, up 20.64% this year. The dividend yield paid by the company is 1.31%.
For Q3 of 2024, it reported a revenue of $28.24 billion, an increase of 24% from a year ago, which surpassed Tesla's $25.18 bln revenue reported for the same period. Byd'sByd's YTD sales meanwhile are $70.53 billion. The company'scompany's strong numbers came despite the EV downtrend in China. In fact, the EV giant sold a record number of cars (370,854) in August. Interestingly, half of BYD'sBYD's sales are hybrid cars, which are growing faster than battery-only cars.
The company, however, is facing headwinds in terms of potential tariff increases from the EU, Canada, and even the US. Meanwhile, the latest reports suggest that BYD is preparing for an intense price war and has asked suppliers to apply 10% price cuts next year. This comes as the company expects to surpass 4.2 million new-energy vehicles (NEVs) in sales this year, driven by a low-cost supply chain, technological innovations, and scale advantages.
Conclusion
Electromobility plays a vital role in combating climate change by significantly reducing greenhouse gas emissions. However, this transition also presents several challenges, such as high production costs and consumer perception. What can help accelerate their adoption is educating consumers about electromobility and battery life, as misinformation can amplify unfounded fears, reducing social acceptance and, in turn, hindering EV market growth. Providing accurate and transparent data, as this study did, can help create a realistic understanding, empower consumers to make informed purchasing decisions, and build consumer trust in EVs.