Lithium ion batteries pose transport challenges

The fragility -- and dangers -- of lithium ion batteries for electric cars came up again at the Automotive News Europe Congress in Paris when DHL's head of automotive logistics pointed out the difficulties of transporting them.

Not only are they heavy, they also are classified as "dangerous goods" when flown, Fathi Tlatli told us last week.

Used battery packs can't be flown by air at all. They must be transported by road.

DHL has had to develop special packaging to carry batteries to protect against temperature fluctuations, shocks and explosions, Tlatli said.

This fragility was at root of Mitsubishi's recent recall of 4,313 plug-in hybrid versions of the Outlander SUV. In one instance the lithium ion battery pack caught; in another it melted.

The problem was traced back to the way the batteries were handled in the factory, where some packs had been dropped while others were damaged in an excessively forceful screening process. The supplier, Lithium Energy Japan, said it had come up with a solution to the problem in May.

The fire risk of lithium ion cells was highlighted back in 2010 when the United States Federal Aviation Administration (FAA) issued a safety alert for operators about the batteries following investigations that determined that a cargo plane that caught fire and crashed soon after taking off from Dubai in 2010 was carrying undeclared lithium ion cells (not made specifically for electric cars). "Our test results … demonstrated that lithium ion cells are flammable and capable of self-ignition," the alert said.

Testing firm EuroNCAP has developed specific crash tests for electric cars but hasn't flagged up any safety issues surrounding the battery packs. The Nissan Leaf scored the maximum of five stars in the tests last year.