Bob Stempel (ex-GM, ex-ECD Ovonics) talks about lithium batteries, and what will make EVs great

Robert "Bob" Stempel, semi-retired at an energetic 78, is one of the good guys. Armed with a mechanical engineering degree from Worcester Polytechnic Institute in Massachusetts, he joined General Motor's Oldsmobile Division in 1958 as a chassis detailer and 29 years later was GM president and chief operating officer under then-CEO Roger Smith.
In 1973, Stempel led development of the catalytic converter used around the world to control exhaust emissions. A couple years later, as Chevrolet's engineering director, he was wowing journalists with encyclopedic knowledge of every Chevy product delivered at press events in his booming voice without written notes. After that, he ran Pontiac Division, Adam Opel AG (in Germany) and Chevrolet Division, then the newly-formed Buick-Oldsmobile-Cadillac group as part of Smith's massive 1980s reorganization of GM's North American automotive operations.

When finance guy Smith – probably one of the worst CEOs in history – retired on August 1, 1990, product guy Stempel took the corporation's tattered helm. For two years, he labored to fix the mess that Smith had left. At the same time, he nurtured and championed GM's fledgling electric vehicle program and was instrumental in recruiting Ken Baker (head of Advanced Vehicle Engineering for Chevrolet-Pontiac-Canada group) to lead the effort. (This post continues after the jump.)

Baker, who had been chief engineer of GM's short-lived 1980s Electrovette (converted Chevy Chevette) EV program, was reluctant at first. "We told him, 'Ken, we've done this before,'" Stempel later recalled, "'but we've got better tools now, a much better controller from Hughes and a much better feel for the batteries. We've got an opportunity here.' So he stepped in and took it on with a real vigor. He was a bit of a visionary, a futurist. He had a personal like for that kind of transportation and was enthused about it. He was definitely a good choice." (Read more about this story in GM's EV1, the True Story.)

When GM's Board decided that the turnaround wasn't going quickly enough – partly because Stempel was too nice a guy to throw entire programs and thousands of employees overboard as fast as necessary – they replaced him in October, 1992. A lesser man might have slunk off into oblivion. Not Bob. He re-emerged three years later as chairman and CEO of NiMH battery, energy efficient solar panel and hydrogen hydride storage pioneer Energy Conversion Devices (ECD) Ovonics and ran that challenging enterprise until he retired in 2007.

When I visited in 2006 to test-drive an experimental hydrogen-powered Prius, Stempel said he believed that such a parallel hybrid was an ideal application for hydrogen – stored in ECD Ovonics-developed solid hydride containers instead of in high-pressure gaseous form – as an ICE fuel. "You can get virtually the same performance," he said.

"We had to add a turbocharger, but the electric motor at the low end provides the torque we need to get off the line. We're at about 200 miles of range now and changing our metal hydrides to get it up to maybe 300 miles. It's a heavy development program for us, and we think there are things we can do with those materials to get the mass down and capacity up. We also have plans to bring the cost down, but it's pretty tough to get it to gas-tank cost."

That was then. What's Stempel up to now? I caught up with him recently by phone and found that he's still not quite retired. "I'm officially retired from ECD and working with some guys as a consultant. A lot of folks used to say, 'Go away, we don't want to hear about electrics.' These last couple years have been a little different: 'Hey, Bob, you got a few minutes? I'd like to talk to you about electric cars.'" He declined to identify his clients, but I'm sure at least one electric vehicle (EV) battery supplier – maybe the same one he led for 12 years – is on his list. Naturally, EV batteries were what we talked about.

"I did move from NiMH to lithium-ion," he said, "and our big drive now is on materials to reduce the cost and at the same time improve the energy and power. As you know, we're going to need a life requirement of eight to ten years, and most of the work I'm familiar with now is focused around the materials.

"Most lithium batteries are structures of materials put together for best energy and power, with the fewest materials possible for cost. The basic cost is in the materials, so using less and less of them – less lithium, cobalt, expensive metals – will make the big difference. Cost is a major effort within the battery industry, and it's starting to bring results."

But isn't labor also a major cost factor in battery pack production? He said a lot of what is now hands-on will become automated, and battery makers are paying more attention to cell-to-cell variation: "Once you get those cells where each one is virtually identical to the next one, the pack process becomes a lot less complicated. And people are working on the controls. When we started with li-ion, you literally had to measure the temperature and the voltage drop in every cell, so the complexity of the controls was horrendous. Now it's getting much simpler."

With li-ion, it's necessary to avoid high and low states of charge, right? "Absolutely. You have to stay away from the top and the bottom because lithium is unstable at full charge, and at full discharge. If you stay in the 20 to 80 percent range, you're pretty comfortable."

Nissan tells me it's using much more than that in the Leaf. "There are some running in the 10 to 90 percent range. Depending on your confidence in your control algorithm, you can stretch that. But if you get below 10, you do have to pay attention. I think GM is being conservative. The last thing they want is a lithium fire in a Volt, so they're going to be very, very cautious about that. Expect that to change with time, though."

Nissan says it's been working on its own li-ion technology for 18 years. "It was only a few years ago when Carlos Ghosn was saying, 'Electric cars, never. Not in my lifetime.' If anyone has changed course, it's him. Part of that is what they've done with the battery, and I give them credit. They have been able to sustain fast charging at the 440-volt level, and they're apparently getting very good life with it."

What about Tesla's pack, which uses 6,000-plus laptop computer batteries wired together in series and in parallel? How can they make – and service – something like that cost effectively? "Their people came from the computer business, and they certainly had the capability to put together an algorithm to control that. But that's too many cells. I think over time, we'll see them shift to a more conventional kind of pack."

Yet Mercedes is using Tesla batteries in its test fleet, and Toyota has partnered with Tesla. "The Toyota/Tesla partnership arose out of a series of other issues. It was really a convenient marriage for Toyota, because they needed to do something with the Fremont plant. When you unravel that story, there's a lot more to it than just batteries. And Mercedes has sold off part of their investment and is backing away from that. That multi-cell concept is very, very difficult, so I think you'll see Mercedes moving toward bigger cells and fewer of them. They wanted to get their feet wet on an experimental basis so were trying a little of everything.

"But Silicon Valley has very knowledgeable people in computer logic and programming, and what will make electric vehicles great over time will be the programs that run it. If you get something that's bullet-proof from a safety standpoint and gives you the performance you want, people will be pounding on your door to get it."

Now that Nissan and others are ramping up availability of EVs that will do exactly that, we'll all be watching very closely.
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Award-winning automotive writer Gary Witzenburg has been writing about automobiles, auto people and the auto industry for 21 years. A former auto engineer, race driver and advanced technology vehicle development manager, his work has appeared in a wide variety of national magazines including The Robb Report, Playboy, Popular Mechanics, Car and Driver, Road & Track, Motor Trend, Autoweek and Automobile Quarterly and has authored eight automotive books. He is currently contributing regularly to Kelley Blue Book (,, Ward's Auto World and Motor Trend's Truck Trend and is a North American Car and Truck of the Year juror.

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