Vast majority of EV batteries will outlast their vehicles-report
Geotab has created the EV Battery Degradation Tool using data based on 6,300 vehicles. Image: Geotab

A study of 21 electric vehicle models — and the introduction of an accompanying interactive tool — brings promising insights for real-world battery longevity

New research released by Geotab measuring the battery life of 6,300 fleet and consumer electric vehicles has provided new insights regarding the lifespan of EV batteries.

“While there has been plenty of research done on battery health, there has been very little data following the real-world performance of EVs over time, let alone comparisons across different makes and models,” writes Charlotte Argue, senior manager of fleet electrification at Geotab. “Until now.”

The key takeaways are quite positive: batteries are exhibiting “high levels of sustained health” over long periods of use.

“If the observed degradation rates are maintained, the vast majority of batteries will outlast the usable life of the vehicle,” writes Argue.  

Modest range loss

Across the 21 vehicle models observed, the average loss to a battery’s state of health was modest — only 2.3% per year. For an EV with a 240-kilometre range, that amounts to only about 27 kilometres of lost range after five years of use.

In conjunction with the report, Geotab also unveiled an interactive tool that users can use to compare rates of battery degradation between cars of different makes, models and years.

Geotab's EV Battery Degradation Comparison Tool
Click the image above for Geotab’s EV Battery Degradation Comparison Tool

The 2015 Nissan Leaf, for example, has an average degradation rate of 4.2%, while that of the 2015 Tesla Model S is only 2.3%. Geotab cites battery pack temperature control as the key difference between these models; the Tesla’s liquid cooling system protects the battery against degradation more effectively than the Nissan’s passive air-cooling system.

Buffers aid longevity

Another key factor in battery longevity is the use of a state-of-charge buffer. Continuous operation of a battery at either its maximum or minimum end can damage its long-term health. As such, cars which utilize large buffers which prevent a battery from becoming entirely depleted or fully charged ensure lower than average degradation rates.

Higher vehicle usage did not statistically show to increase rates of battery degradation. However, frequent usage of direct-current fast chargers, as opposed to 120V or 240V chargers, appears to accelerate degradation. Vehicles driven in hot climates (more than five days per year over 27°C) were also shown to have higher rates of battery degradation than those which remained in more temperate conditions.

1 comment
  1. A good short article! As a person who has put on over 105K KMS on his 2017 Leaf, I can speak to some of the issues. Your last paragraph is excellent because it discusses ‘real world’ findings. However, a 2015 Leaf and Model S are not a good representation of the EVs (and their batteries) on the highways now. Leaf Spy Pro is an excellent tool for Nissan users to find out about their battery degradation. My degradation is above the average, it could be due to the high usage of Level 3 chargers. Although, what about the number of times the battery has gone under 10% capacity – does that affect it? What about the amount of time it spends in a Level 2 charger after it has been fully filled? There are lots of variables surrounding EVs.

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