EV battery failures dropped drastically after the 2015 Tesla Model S

Makers of modern electric cars can easily give 8-year battery guarantee and even push for 15-year warranties at 85% capacity.

The advancements in battery chemistry, pack cooling, and production process refinements have all led to a breathtaking drop in EV battery failure rates in recent years.

Just back in 2011, the failure rate of new electric car batteries hence warranty replacements stood at the whopping 7.5%. For the whole 2011-2023 period, however, it stands at 1.5%, mainly because something happened after 2015.

In 2016 and every year thereafter, the warranty EV battery replacements due to unexpected failure has stood at half a percentage point or less.

One look at the electric cars that have historically logged the highest battery failure rates puts the abrupt reversal into perspective.

In the early Model S years, the cooling of some battery packs that Tesla used was underengineered, and they suffered from insufficient thermal management. This led to a number of premature Model S battery pack failures, setting the record at 8.5% for the first 2013 model year, then 7.3% in 2014.

In 2015, however, Tesla took notice and started introducing batches with upgraded battery chemistry and thermal management system. This basically eradicated the exorbitant battery failure rates of the Model S, and it fell in line with the very low industry average afterward.

The only other major offender outside recalls was the Nissan Leaf. Its 2011 and 2012 model years kept the EV battery failure rates high before the Tesla Model S took the torch and its first editions carried it until 2016.

That's not to say that there haven't been worse years for failing batteries in new electric vehicles, as 2017 set a record with more than 11%. These rates, however, were due to major recalls of vehicles like the Chevy Bolt EV and EUV models or, more recently, of the Hyundai Kona.

Last year marked the lowest number of warranty EV battery replacements due to sudden failure. There were also no major recalls, and the argument point about EV battery safety and longevity seems to be largely moot now.

Modern electric car batteries are projected to last at least 15 years of operation, according to Tesla founder JB Straubel who now owns a major recycling operation called Redwood Materials. Some researchers put the battery lifetime number at more than 20 years even.

This explains why the world's biggest battery maker CATL and NIO are pushing for a mandatory 15-year EV warranty, which they say will be instrumental in creating a vibrant market for used electric vehicles other than Tesla.

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