Most EV Batteries will Outlast Their Vehicles According to Geotab Analysis

December 17, 2019 by Paul Shepard

How long does an electric car battery last? - asks Charlotte Argue, Senior Manager, Fleet Electrification at Geotab in a recent blog posting. The posting continues: Use the free EV battery degradation tool to compare the average battery degradation over time for different vehicle makes and model years. Geotab developed the tool based on an analysis of 6,300 fleet and consumer electric vehicles.

We analyzed the battery health of 6,300 fleet and consumer EVs, representing 1.8 million days of data. From the telematics data processed, we have gained insight into how real-world conditions influence the battery health of electric vehicles, providing aggregated average degradation data for 21 distinct vehicle models, representing 64 makes, models, and years.

From a life-cycle perspective, battery performance and health really are the key to it all. As the battery is the most expensive component in an EV, not only does battery health affect the vehicle's residual value (helping to answer the cost question), but it also has a direct impact on maximum usable range over time.

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How long will an EV battery last?

You might have noticed that it is tough to get a straight answer to the battery-life question. What you might find instead are statements that batteries are covered by warranty should something go wrong. Typically, battery coverage is 8 years/100,000 miles, but this will vary by manufacturer and country.

What is reassuring is that battery costs are decreasing significantly year over year. This is true. Since 2010, the price of an average lithium-ion battery pack has dropped by over 80%.

An automaker's guarantee of their battery technology and the promise of decreasing costs should inspire some confidence. However, wouldn't it be much better to know how quickly your battery is expected to degrade, and how to minimize this loss?

What is EV battery degradation?

Battery degradation is a natural process that permanently reduces the amount of energy a battery can store, or the amount of power it can deliver. The batteries in EVs can generally deliver more power than the powertrain components can handle. As a result, power degradation is rarely observable in EVs and only the loss of the battery's ability to store energy matters.

A battery's condition is called its state of health (SOH). Batteries start their life with 100% SOH and over time they deteriorate. SOH is a measure of how much energy the battery can deliver (kWh).

Keep in mind, this is not the same as vehicle range (distance the vehicle can travel on those kWhs) — which will fluctuate on a daily or trip-by-trip basis, depending on a number of factors including charge level, topography, temperature, auxiliary use, driving habits, and passenger or cargo load.

Common factors impacting lithium-ion battery health:

  • Time
  • High temperatures
  • Operating at high and low state of charge
  • High electric current
  • Usage (energy cycles)

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. Until now.

Introducing the EV Battery Degradation Tool

Geotab created the EV Battery Degradation Tool to assess how batteries have been holding up and to consider the relative importance of the above factors on EV battery life under real-world conditions.