WHEN IT COMES TO BATTERY TECHNOLOGY, the automotive industry beats aerospace hands down, a topresearcher says.
Bob Taenaka,battery technical lead, spent more than a decade designing batteries for spacecraft while working for Hughes Aerospace. After moving to Ford 10 years ago, he found it much harder to design batteries for automobiles than for rocket ships.
“There's a better-controlled set of circumstances for spacecraft batteries,” Taenaka says during a technology backgrounder in Dearborn, MI. “In automotive, you have some customers that may park their vehicle for a month, while others drive every day and aggressively. So there's a wider range of duty cycles.”
Adding to the difficulty is price sensitivity. In aerospace, keeping costs down is far less important, he says.
Leveraging his knowledge of advanced batteries, some gleaned while working on the Galileo spacecraft that traveled 450 million miles (724 million km) to Jupiter in 1995, Taenaka, along with Ford's battery team and supplier-partner Sanyo, helped develop the nickel-metal-hydride battery pack that powered the first-generation Ford Escape Hybrid.
That was followed by the Fusion Hybrid, which featured the auto maker's second-generation powertrain allowing electric-only speeds of up to 47 mph (76 km/h) and featuring a battery pack with 20% more energy density.
Ford recently bought back some Escape HEVs that, combined, had racked up millions of real-world miles for teardown and evaluation. Included were vehicles that served in Yellow Cab's San Francisco fleet and had accumulated more than 250,000 miles (402,336 km) during their tour of duty.
“I was very impressed,” says Chuck Gray, chief engineer-global core engineering for hybrid and electric vehicles. “Normally, with a taxi at the end of its service life, there's more degradation in the powertrain system.
“While we had very good simulations and tests, with the battery in particular, we're seeing results that are even better than our testing,” he tells Ward's.
Even after a quarter-million miles, the battery cells still had 85% of their original energy capacity, engineers say.
Of the 42.6 million individual cells that went into the nearly 190,000 HEVs Ford has sold, only five have failed, with the last failure occurring in 2007, the auto maker says.
“The odds of experiencing an issue with one of our hybrid battery cells is 8.5 million to 1 — about the same odds as a person being struck by lightning,” Gray notes.
While Ford's hybrid system and NiMH batteries have proven durable, the auto maker faces additional challenges with new HEVs, plug-in hybrids and electric vehicles launching soon.
Among unknowns is whether lithium-ion batteries will hold up as well as less-advanced NiMH units.
With the launch of the Focus EV slated for later this year and the C-Max PHEV and HEV cross/utility vehicles to follow, testing on the Li-ion packs is well under way, Gray says.
“We're finding our test results match what we have planned. We're very confident.”
Ford Electric Vehicle Strategy Evolving
Ford to Bring Electric Vehicle to Market in 2011