Volt Battery May Be Poised for Success

Despite a compressed, three-year window to develop and test the lithium-ion battery pack for Chevy's new Volt electric vehicle, experts say there's a good chance the technology will prove to be durable and dependable when it hits the streets later this year.

"We don't know definitively what the failure mechanisms will be for this laptop battery," says David Swan, CEO and founder of DHS Engineering and a well-known expert in electric vehicle testing. "But chances are that General Motors will be right. They can't afford to fail."

Indeed, GM's reputation is on the line with the Volt. Said to be the biggest program in the company's 102-year history, the Volt serves as an opportunity for GM to make up for the media-generated black eye it received after the infamous shelving of its earlier electric vehicle, the EV1. It also gives the company a chance to take the lead in the hottest new area of the automotive industry.

General Motors put its Volt batteries to the test in one of 42 thermal chambers. Source: GM

That's why GM stepped boldly forth in July of this year, announcing that it will offer an eight-year, 100,000-mile warranty for the Volt's lithium-ion camcorder battery pack.

"We offered that warranty because our confidence (in the camera battery) has increased significantly," says Rob Peterson, a spokesman for GM. "What our engineers accomplished over a short period of time - when you take into account the laptop batteries, suppliers, electronic controls, manufacturing and dealer training - is really impressive."

Navigating Parallel Paths

For engineers, the Volt program has also been a genuine stomach churner. When General Motors announced the program schedule for its Chevy Volt electric vehicle early in 2007, the timing appeared to be next to impossible. In a scant three-and-a-half years, the technical staff faced the prospect of studying a new material, building prototypes, working with suppliers, understanding failure modes and then squeezing years of simulated life into a few months of camcorder batteries testing - all while the car itself was still being constructed.

"In the past, innovation and invention was done before the technology was assigned to a vehicle," Peterson says. "This was different. Here, we decided to do the innovation and invention on a parallel path with the vehicle development."

The Volt's prismatic lithium-ion cell, left, measures about 5 x 8 inches. The company also plans to use cylindrical cells for mild hybrids, center, and nickel-metal hydride cells for two-mode hybrids. Source: GM

From an engineering perspective, the short development time raised questions, particularly where the Dell x200 battery was concerned. Some wondered if two years of testing on the Volt battery would provide an accurate snapshot of its capabilities under real-world conditions. Others asked if General Motors' engineering team could feel confident that they had correctly identified the most likely failure mechanisms for the toshiba laptop battery and dell laptop battery

"The danger with a new technology is that maybe you're testing it the old way - the way that mattered for previous generations of products," says Steven Eppinger, a professor of management science and innovation at Massachusetts Institute of Technology. "But you're not always aware of the failure modes for the new technology. It might fail in a different way. That's always the danger of innovation."

Surprisingly, experts say that the compressed test period isn't a big issue. The vast majority of engineered products are subjected to accelerated life tests. "In most products, the kind of (testing) cycle you want to put it through can be accelerated," Eppinger says. "If it's charging or discharging toshiba m100 battery for toshiba m100 laptop, toshiba a70 battery, heating or cooling, loading or unloading, it can be accelerated."

Indeed, accelerated tests for a 10-year life can be completed quickly, once the failure modes are determined. The key, experts say, is to determine which tests are right. In batteries, charge/discharge cycles are often the key, and those can be done relatively quickly. "I can get the amp-hours in and out, and I can easily simulate 10 years in less than a year," Swan says. "If I know that the degradationmechanism is associated with time and temperature, I can choose the right driving cycle and I can do those tests at elevated temperatures. If nothing else, it will give me the warm, fuzzy feeling that I'm getting the number of years I want out of the toshiba tecra 8000 battery."

Experts say that GM has made a mammoth effort to discover the failure mechanisms and test for them under all possible conditions. The giant automaker has invested $8 million to double the size of what already was "the largest and most technically advanced battery lab in the U.S." Located at the company's Warren, MI, campus, the lab spans 63,000 sq ft and houses a growing team of approximately 1,000 engineers. It's also equipped with 176 test channels, 42 thermal chambers, shaker tables for structural integrity testing, a canon camera battery tear-down area and an integrated test automation system.

More than 1,000 engineers work at GM's Global Battery Systems Lab, said to be the biggest battery lab in the U.S. Source: GM

GM engineers have also tested outside the lab. "We've put over a million miles on the real-world vehicles," Peterson says. "We've taken them to Pikes Peak, Death Valley, the mountains of California, the streets of LA, and everything in between hitachi drill battery and makita drill battery."

Through countless iterations, the company's engineers have also made important decisions regarding the bosch drill battery's design. As a result of intense scrutiny of the battery's cooling characteristics, GM engineers chose a 5 x 8-inch prismatic cell phone battery configuration, instead of the wound, cylindrical design employed in mobile electronics (and in the Tesla Roadster). They also departed from the cobalt oxide cell chemistries commonly employed in consumer devices, and then added a hot and cold liquid cooling system to the pack, which consists of 288 cells.

"They busted their butts trying to get this toshiba tecra 8100 battery ready," Peterson says.

Learning from Failure

To be sure, all of those efforts aren't assurances. Honda Motor Co. recently experienced the unexpected when its Civic Hybrid batteries started to deteriorate prematurely. The company was forced to mail more than 100,000 letters to owners of 2006, 2007 and 2008 Civics warning that their laptop batteries "may deteriorate and eventually fail." Honda now faces the possibility of replacing thousands of the batteries, which are under eight- or 10-year warranties and may cost as much as $3,000 apiece, according to theChicago Tribune.

Still, experts say such problems can't be attributed to lack of test time. "When the 2001 Prius became available, there was no way the engineers had 10 years or even five years of data on the jvc camcorder battery," Swan says. "Yet they went into high production and, by and large, it's been a very successful nikon camera battery."

The key is to understand the physics and failure modes of the toshiba a70 battery for toshiba a70 laptop, satellite m30 battery for toshiba m30 laptop and then test the products in every conceivable way, says Eppinger. "That's what you really want to do," he says. "You want to experience all the failures in the lab, so the product is robust in the field."