To quick charge or not to quick charge?

To quick charge or not to quick charge?

Idaho National Laboratory (INL) is doing an excellent job these days in evaluating electric vehicles.

One of the labs projects is "Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study," which was presented at the SAE Hybrid and Electric Vehicle Technologies Symposium last month.

INL is testing Nissan LEAFs (2012 model year) and battery packs in the lab.

The vehicles are being tested in tough environment for the LEAF - in Phoenix, AZ where temperatures diminish the LEAF's pack capacity more quickly than in milder areas.

Two LEAFs are charged slowly - 3.3 kW, the others are quick charged with power up to 50 kW. All the other criteria is basically the same:

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – On Road Cycling Design

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – On Road Cycling Design

Here is some data and performance after initial tests:

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – Vehicle Performance Testing

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – Vehicle Performance Testing

Now, every LEAF exceeds 40,000 miles and are on the way to the 50,000-mile, when test will come to an end.

Gathered data indicates major effect from mileage on capacity in such conditions.  The impact of quick charging is negligible.

Two LEAFs, which were quick charged at 15-times higher power every day have no more than ~3% lower capacity after 40,000 miles. This is basically 0%, especially when you consider that typical drivers will use QC maybe once a week, so what will be the difference - like 1% maybe?

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – Results to Date

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – Results to Date

However, capacity drop itself is high in LEAFs in Phoenix and this is not good. 20-25% after just 40,000 miles in tests.

We are interested to see how such results would look in Washington state or a similar mild climate environment - AC vs. DC charging.  Hopefully, the DOE will throw some additional grant money to Idaho National Laboratory for this sort of testing, too.

Interesting is the range graph with identification of the seasons in the table:

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – Results to Date

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – Results to Date

Soon, INL plans to finish the tests and present a full report. Battery tests in the lab have one more year of testing to go.

Source: DC FAST, WIRELESS, AND CONDUCTIVE CHARGING EVALUATION PROJECTS - Matt Shirk, Idaho National Laboratory