The Destructive Power of High Temperatures on the Longevity of EV Batteries
In a peculiar twist of fate, electric vehicles, hailed for their positive impact on climate change, face a challenge in extreme heat.
An irony that becomes increasingly evident as several states in the U.S. endure scorching heat waves of escalating frequency and intensity.
While high temperatures do not render battery-powered vehicles powerless, EVs in hot climates need to work harder to maintain optimal battery and passenger temperatures. However, on a molecular level, excessive heat can be likened to heart disease for EV batteries or a slow and insidious form of cancer.
This is due to the fact that as temperatures rise, the ions within a car battery accelerate. Consequently, they often struggle to effectively bind to the anode or cathode. Moreover, the pressure and speed generated can result in microscopic cracks, impeding chemical reactions and diminishing the overall usable life of the battery.
To some extent, this phenomenon occurs during any fast-charging cycle. The ions move more rapidly when utilizing a Tesla Supercharger compared to charging from a wall outlet, and the heat generated from rapid charging is one of the reasons why smartphone batteries do not charge faster. However, during extremely hot days, the ions in an EV battery exhibit heightened activity even when the car is stationary or not connected to a charging station, significantly limiting the vehicle’s range in an irreversible manner.
Scott Case, co-founder and CEO of Recurrent, a startup that provides battery health reports to EV customers and dealers, explains, “The worst case scenario is a car left unplugged in an unconditioned garage in Phoenix throughout the summer. The battery will deteriorate rapidly.” Conversely, if the vehicle is plugged in, it can utilize the charging power to maintain an optimal battery temperature.
The Impact of Temperature Extremes on EV Batteries: Cold Weather vs. Heat Challenges
Cold weather also affects EV batteries. The colder it gets, the slower the chemical reactions occur, resulting in reduced battery capacity. However, these losses are temporary; once spring arrives, a battery in snowy Michigan or chilly Maine will recover its full functionality. On the other hand, heat can permanently reduce the maximum range of an EV.
Case emphasizes the challenge faced by individuals residing in hot climates, stating, “You can educate people, but it is unfair to say, ‘Don’t live in Phoenix.'”
As the adoption of EVs progresses in tandem with rising temperatures, drivers worldwide will need to familiarize themselves with best practices for maintaining battery health. Notably, some of the highest rates of EV adoption are concentrated in hot regions within the United States, including California, Florida, Texas, Arizona, and Georgia, accounting for 56% of the nation’s battery-powered vehicles, according to the Department of Energy. Fortunately, proactive measures can alleviate the impact of extreme heat.
Exemplary EV Battery Practices and the Growing Significance of Battery Health in the Market
Skyler Williams, an entrepreneur based in Austin, Texas, who acquired a Rivian R1S last August, seeks shade during scorching Texas summers as a precautionary measure. He charges his vehicle at fast stations only when necessary, keeps his truck plugged in while parked in the garage, avoids charging the battery beyond 80%, and employs Rivian’s app to open the windows remotely on hot days. Nearly a year later, his EV has not experienced any loss in range, which bodes well for its resale value.
Battery health is increasingly becoming a crucial metric in the EV market, driving the pursuit of granular methods to assess it. Stephanie Valdez Streaty, Director of Strategic Planning at Cox Automotive Inc., reveals that four out of five EV shoppers now consider battery longevity when making a purchase, motivating her team to develop a proprietary score for measuring battery health.
While still engaged in extensive research and development, Streaty envisions a future where buyers will have the option to purchase used EVs with transparent information on battery health, emphasizing its significance.
Harnessing Data for Accurate Battery Scoring
Recurrent has taken a step forward. The company gathers battery metrics from over 17,000 EVs registered for its service three times a day. Utilizing this data, Recurrent can rapidly assign a score to any EV by assessing its estimated range, state of charge, and odometer. Capturing data while a vehicle is charging further enhances the accuracy of the assessment.
For example, an EV that has endured several scorching Texas summers may receive a lower score compared to an identical model with similar mileage located in a temperate climate. Conversely, a Texas driver who has taken all the necessary precautions for their EV could attain a higher Recurrent score than an equivalent vehicle in a cooler climate that undergoes routine depletion and full recharge cycles, practices that contribute to wear and tear on lithium-ion batteries.
Scott Case observes, “Manufacturers compete on three aspects: overall range, charging speed, and cost. But they will also be held accountable for a fourth aspect: ‘How long will these vehicles last?'”
Regulators in California are currently considering a proposal that would mandate the inclusion of a measure of battery health for every EV sold. Presently, dealerships in hot climates constitute some of Recurrent’s most valued customers, as there is often a significant discrepancy between the actual range and the officially “certified” range determined by the U.S. Environmental Protection Agency.
Scott emphasizes, “EPA range certifications are inaccurate from day one as they fail to account for temperature variations. This is a crucial transition that everyone must recognize.”
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