The Mysterious 400-Mile Electric-Car Battery: Does It Really Exist?

Last Updated Apr 11, 2011 7:29 PM EDT

With electric cars struggling to achieve 100 miles of range, it's an understatement to say that everybody wants to see a battery breakthrough. The consensus is that there's nothing around the corner in the short term that much improves on conventional lithium-ion, though solid-state batteries and other technology could be important longer-term plays. But what's this about a low-cost, lightweight, 400-mile-per-charge battery from Germany?

DBM Energy's Kolibri lithium-metal-polymer battery has made some headlines, but it turns out to be wrapped in as much intrigue as a Tom Clancy novel. There may be something there, despite the drama, but the "breakthrough" could turn out to simply be a very big 98-kilowatt-hour battery pack, and anyone could get a lot of range out of that.

Let me get this straight...
And there are still a lot of unanswered questions. What would a commercial DBM pack cost? Would it fit into a car, and what does it weigh? How many watt-hours per kilogram? What is the recharge time? That last point is critical, because big packs are often really, really slow to recharge.

Whenever there's a lot of hype about something, you have to remember the Segway introduction, which was supposed to change the world as we know it but created nary a ripple. The DBM battery could turn out to be another Segway.

A lightweight Audi A2 carrying the company's battery pack reportedly traveled 372 miles on a single charge from Munich to Berlin last October, with 20 percent of its life remaining. That's certainly good -- even Tesla Motors hasn't done any 400-mile-equivalent runs (though it did get 313 miles last year). But the DBM pack is, in fact, about the same size as that scheduled next year for the Tesla Model S, which is supposed to yield at least 300 miles of range. That Tesla battery is rumored to have impressive energy density of 240 watt-hours per kilo. If some reports are right, the DBM pack is over 300 -- but the reports might not be right.

Chelsea Sexton, a prominent electric car consultant, isn't quite ready to turn her thumbs down, but she has many questions, too:
I'd wonder about any batteries that can't get three miles per kilowatt-hour in an Audi A2, and I find it sketchy that it made news on that basis alone. As for light and cheap, look forward to seeing that verified by a credible third party, and at automotive production levels.
Slippery when asked for proof
DBM probably did make that record run, but the details (how many people aboard, for instance) are important. It takes a really rigorous process to ensure that all the useful data is recorded. It's also unclear if the DBM team was under observation at all times, though witnesses are claimed.

But the company has been a slippery eel on validation. DBM Energy's battery work is supported by the German economics ministry (with $370,000 in funding), but before any official testing on the miracle pack could be done... disaster struck! In December the car that had reportedly made that history-making run burned up mysteriously in a warehouse fire. A dog ate the homework, in other words.

DBM said it would stage a second record-setting run in February, but then it got really cold at the test track, the test was postponed, and so was a planned showing of a DBM car at a German electronics show in March. At this point, anyone could see parallels to the exaggerated claims made by Texas-based EEStor, which said in 2008 that its ultra-capacitors had three times the energy density of lithium-ion batteries at much reduced cost, and would power an EV with 250 miles of range. But it delivered-- nothing at all.

And then April 1 (April Fool's Day, of course), DBM claimed it had passed rigorous tests at the German Federal Institute for Materials Research and Testing "with flying colors." But those tests were mostly about safety issues -- the batteries didn't catch fire, leak, or "decompose." Still pretty inconclusive, and performance tests (not on the road, but on a dynometer) at the DEKRA certification agency didn't entirely clear things up, either. They were done on a smaller 62.9 kilowatt-hour pack for some unexplained reason, and they yielded 284.5 mile range. Extrapolated, that means 443 miles for the larger pack tested earlier.

Vindication? Not yet. DBM claims a "worldwide record" in its Munich to Berlin run, but it better be ready to replicate it -- over and over again.

(Thanks to Peter Hoffman of the Hydrogen & Fuel Cell Letter for the tip.)

Related: Photo: DBM Energy
  • jim motavalli

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