New study finds “vast majority” of EV batteries will outlast the vehicle

In stark contrast to the fears and propaganda aiming to undermine the electromobility transition, a new study of actual electric vehicle (EV) usage reveals less battery degradation than previously observed, with the “vast majority of batteries” likely able to outlast the usable life of the vehicle.

Canadian telematics company Geotab recently published an update to a 2019 analysis of EV battery degradation with updated data and analysis from fleet usage.

In the original blog post published five years ago, Geotab found EV batteries degraded at an average of 2.3 per cent per year which, at the time, was nevertheless “surprisingly good”.

The latest analysis – which boasts a sample of 10,000 EVs – indicated that EV batteries have improved in the intervening years, degrading at only 1.8 per cent per year on average.

Geotab concluded that EV batteries could last 20 years or more at this degradation rate. If an EV battery degrades at 1.8 per cent per year, it would still have over an 80 per cent state of health after 12 years – “generally beyond the usual life of a fleet vehicle.”

Degradation in batteries is a normal result of use: as anyone with a mobile phone can attest, the amount of charge you have left at the end of the day can decline dramatically from when you first bought it through two or three years of use.

As Geotab explains, a 60kWh battery that starts its life with a 100 per cent state of health (SoH) that deteriorates to 90 per cent SoH would “effectively act like a 54kWh battery”.

However, while a degradation rate of 1.8 per cent is relatively impressive, overall battery degradation is expected to decline non-linearly – meaning that, after an initial drop and a period of plateauing, towards the end of its life the battery will experience a more dramatic, precipitous drop (as seen below).

Data to demonstrate this non-linear drop-off is limited at this stage, however, given the relative immaturity of the EV market.

In time, more data will provide more concrete conclusions about a battery’s end-of-life behaviour, but Geotab’s current conclusion is that “EV batteries will outlast the useful life of their vehicle, especially if drivers follow charging and driving best practices.”

In this vein, Geotab also discovered that high-use electric vehicles did not show significantly higher battery degradation than others” and that fleet managers should not be concerned to put their EVs through “high-use duty cycles”.

“However, analyzing the same vehicle model in a high-use situation exposed to different climates and charging power, we saw a strong correlation between high temperature climates, frequency of high power charge usage and battery decline.”

Similarly, Geotab found “an observable difference in battery health between cars that routinely charge on Level 2 compared to those that used Level 1, but the difference is not statistically significant.

“On the other hand, the use of [direct current fast charging (DCFC)] equipment 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.”

Several best-use practices were subsequently determined, including minimising DC fast charging and avoiding keeping vehicles sitting around with a full or empty charge, with the ideal keeping a vehicle’s state of charge between 20 per cent and 80 per cent.

Geotab’s complete analysis of its EV data can be found here.