• Nissan's data shows that EV batteries aren't degrading much
  • Companies are working to increase battery durability
  • Range should increase in the next several years

The Nissan Leaf electric car has been available for more than a year now and most of the early electric car adopters who have purchased them seem satisfied with their choice. Initial concerns about battery longevity had some consumers and many pundits worried that their ranges would decline over time.

How these batteries perform over the life of the car is still unknown, but a year into real-world EV driving Nissan says the Leaf's batteries are performing well.

"Battery durability is about what we expected because our pre-launch testing indicated we wouldn't see much degradation over time," Mark Perry, Director of Product Planning for Nissan, told AutoTrader.com on the sidelines of the 26th Electric Vehicle Symposium in Los Angeles. "In high temperature climates we are seeing slightly more degradation than in moderate and cold temperatures, but it's still within normal ranges."

According to Perry, Nissan expected to see a decline of about 2-3% battery capacity per year so that after about 10 years consumers may have a battery pack that has 70-80% of its original range. For the most part, he said, Nissan's own data collected on millions of miles of EV driving during the last year shows that the more than 11,000 Leafs sold in the U.S. haven't lost more than about 1-2% of their range - meaning real-world experience is slightly better than that predicted during research and development.

That doesn't mean it's all good news for the owners of electric cars though. A limited driving range on a full charge is still viewed by many would-be EV owners as a significant barrier to adoption. Although most people don't drive more than 40 miles in a given day, even experienced Leaf drivers are saying they occasionally have days where the so-called "Range Anxiety" creeps in and they find themselves wondering if they pushed their cars too much and if they'll make it back home.

While many Leaf owners are seeing average driving ranges of 90-100 miles on a full charge, the EPA officially rates the car with a range of 73 miles. Nissan says they are working to introduce new battery technology that will increase this range in the near future but declined to provide specifics.

To get an idea of what kinds of range improving technologies are finding their way into commercially-produced batteries in the next year or two we sat down with Alan Nelson, the Research and Development Director for the Dow Energy Materials division.

Nelson says that the technology Dow is introducing to the commercial market right now is really focused on improving battery durability, namely special coatings applied to the internal battery cathodes and anodes that will help mitigate the degradation in range over time that companies like Nissan are worried about.

"In the next several years we will start to see big improvements in battery capacity and electric car range, but in the near term we are looking at improving durability," said Nelson, adding that a doubling of range was totally within reach within three to five years.

What it means to you: Real world experience shows that electric car batteries are proving to be durable. However, given that many car buyers are still worried, increasing battery range can't come soon enough if EV manufacturers hope to increase sales in a big way.

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Nick Chambers is a "next generation" car enthusiast, recognized for his green automotive coverage in Gas 2.0, The New York Times, Popular Mechanics, HybridCars.com and PluginCars.com. In addition, he's been syndicated in Matter Network, AP and Reuters.

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