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Safety first

A lot is riding on the batteries that will power tomorrow's hybrid vehicles

Mary Ann Wright, CEO of Johnson Controls-Saft Advanced Power Solutions, says the photo taken next to her Ford Escape Hybrid of her with her dog, Dexter, and her company's engineers and their families serves as a reminder of the importance of safety as her company develops lithium ion batteries for use in cars and light trucks.
MILWAUKEE — Mary Ann Wright recently invited her engineers to bring their children to work. While there, they paused for a picture next to her Ford Escape Hybrid. The general manager of Johnson Controls Inc.'s hybrid systems group who also heads Johnson Controls-Saft Advanced Power Solutions had helped develop the vehicle in her previous post at Ford Motor Co.

That photo served to remind the engineers that they have to get the lithium ion batteries they're developing right. Someday lives might depend on their work.

Safety is the 800-pound gorilla in the world of lithium ion batteries.

Wright constantly reminds her engineers that the end users of their work will not be automakers; they will be the people who buy the cars.

For Wright, 45, the consequences of getting it wrong are simply unacceptable. Set aside the worst-case scenario, in which someone is injured or killed. Even a less-severe accident would be intolerable. If the lithium ion battery packs in hybrids overheat or catch fire, the legal costs could be enormous and the damage to her company's reputation huge. It could be years before car buyers regain trust in the batteries.

Already wary?

Consumers already may be wary of lithium ion batteries. Overheating by those batteries led to fires in laptop computers and massive recalls. But lithium ion batteries are widely viewed as the next leap in hybrid technology.

With roughly half the weight and twice the power or energy of the nickel-metal hydride batteries powering today's hybrids, lithium ion batteries will enable a hybrid to travel farther on electricity. They'll boost fuel economy and lower emissions. And the new batteries will make plug-in hybrids possible.

Toyota Motor Corp. was widely expected to debut its lithium ion batteries in the next-generation Prius in 2009. But the automaker reversed course this summer. Now it says the next-generation Prius will stick with nickel-metal hydride batteries.

At General Motors' battery lab in suburban Detroit, test machines run 24 hours a day, charging and discharging lithium ion battery packs from Johnson Controls-Saft, A123 Systems, Compact Power and other would-be suppliers. Those machines push the batteries to their limits and monitor every facet of the batteries' performance.

Ford Motor Co. also is taking its time evaluating the new batteries. "Putting something out there that isn't right could destroy the image of the technology," says Nancy Gioia, Ford's director of sustainable mobility technologies and hybrid vehicle programs. "I'd love to be first, but my goal is to get it right."

GM has placed a big bet on lithium ion batteries, which will power its Chevrolet Volt. GM believes the batteries will be ready for production by 2010 or 2011 and is advertising the Volt electric vehicle concept on TV and on billboards around the country.

GM, Ford, Toyota, Chrysler LLC and others are running test fleets of hybrids with lithium ion batteries in a number of countries under extreme temperatures and various driving conditions.

With Toyota tapping the brakes on its lithium ion batteries, Johnson Controls-Saft now could be first on the market with the product.

The company plans to ship the batteries next summer to Daimler AG for use in a Mercedes mild hybrid sedan and then to BMW AG for a similar use. Johnson Controls-Saft also has battery contracts with GM for a plug-in version of the Saturn Vue, and with several other automakers for lithium ion batteries.

Johnson Controls-Saft is a Franco-American joint venture. Johnson Controls Inc., a supplier best known for its interior components, also dominates the replacement lead-acid battery market with numerous brands sold at auto parts stores and dealerships. Saft, a giant French battery company, makes lithium ion batteries for military and industrial uses.

Safety first

There are two keys to safety with lithium ion batteries:

1. Manufacturing. The batteries must be assembled in temperature-controlled, dust- and dirt-free plants that are as clean as hospital operating rooms. Even the slightest metal contamination inside the batteries could lead to an internal short circuit.

2. The control system. The batteries need some sort of electronic nanny to watch over each cell and remove those with flaws.

Johnson Controls-Saft makes the batteries and binds them into ready-to-plug-in packs. Those packs have a management system that can be tailored to a specific vehicle. That's the company's advantage over suppliers who make only batteries, Wright says.

Wright is the engineer who took over the Ford Escape Hybrid program. Although the vehicle was launched a year late, the debut had no technical glitches.

Since joining Johnson Controls-Saft last summer, she has added hybrid veterans, including several from Ford, to her team. Hers is one of the few engineering teams in the business that has put a full hybrid on the road, she says.

Craig Rigby, Johnson Controls-Saft vice president of systems engineering for hybrid battery systems — a Ford veteran who worked on the Escape Hybrid — says battery safety systems are more complex for lithium ion battery packs than they are for nickel-metal hydride batteries.

In a Toyota Prius, Rigby says, the battery pack is monitored as a whole. That strategy may not be the safest with lithium ion batteries.

Different challenge

"The challenge with lithium ion is a little different from what you do with nickel-metal hydride. It really demands that you monitor certain characteristics of the cell at the cell level," he says.

If one cell overheats, perhaps because of a cooling issue, voltage spike or manufacturing flaw, it can start a fire that spreads to other cells. But the sixth-generation Johnson Controls-Saft system isolates a cell to prevent it from overheating.

Says Rigby: "The software will say, 'OK, if I see a cell that is getting too high a voltage or with a temperature peaking from the rest, I will take action.' If eventually it reaches a point were we need to shut down the system, we will."

But that shouldn't happen. "If everything is working normally from the point of view of how the cells are functioning, you wouldn't see those hot spots," Rigby says.

At Johnson Controls' battery laboratory in suburban Milwaukee, the company is preparing its prototype battery technology, battery management systems and mass-production procedures.

Tapping Saft know-how

A pilot production line lets engineers, working with their Saft counterparts in France, fine-tune a mass-production system for automobile-sized lithium ion cells.

Saft has experience in making very large lithium ion batteries for military uses. The challenge for Johnson Controls, and other companies, is to develop a way to crank out the batteries quickly and at low cost, in a package appropriate for cars and light trucks.

This will be a big job. Automated machines assemble the batteries' internal parts in the laboratory setting. But the process is neither flawless nor fast.

In one lab, white-coated technicians oversee the machines as they slowly turn out the batteries' innards in a temperature-controlled, clean room.

Sheets of copper and aluminum that make up the anode and cathode are coated with compressed carbon and other substances. The sheets are separated by a sheet of porous plastic and then rolled into compact cylinders. Then the center pin is installed and buttoned up by a laser welder. Next, the battery is filled with electrolyte.

Lithium ion battery production is evolving. One recent recall of Sony Corp.'s computer batteries was traced to a manufacturing flaw. Tiny, almost microscopic shards of metal inside the batteries caused them to overheat and catch fire.

That's why Wright will tell you that an anode, a cathode, a center pin, an insulator and various chemicals are just the start when making a lithium ion battery.

She adds three things: families, children and pets. She won't be satisfied until her engineers give her the go-ahead to swap the nickel-metal hydride batteries in her Escape Hybrid for a Johnson Controls-Saft lithium ion battery pack. Then she'll drive off with Dexter, her beefy Rottweiler, in the back.

In other words, the job's not done until the batteries are safe enough for canine, and human, customers.  

You can reach Richard Truett at rtruett@crain.com

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