- SPECIAL REPORTS
Early generations of green vehicles, such as the trendsetting Prius hybrid sedan, relied on nickel-metal hydride batteries. But, lithium-ion batteries are today’s hot technology in the auto industry. In fact, Toyota Motor Corp. (Nagoya, Japan) plans to start using lithium-ion batteries in its popular Prius later this year. .Toyota also recently created a dedicated R&D department that aims to develop a next-generation battery that can outperform current lithium-ion technology
Because lithium is lighter than nickel-based alternatives, lithium-ion cells reduce battery weight and volume by more than 30 percent.
“The replacement of nickel-metal hydride batteries with lithium-ion enhances energy density two to three times, which [is] ideal to drive electric vehicles,” notes Anjan Kumar, a senior research analyst at Frost & Sullivan Inc. (San Antonio). But, lithium-ion batteries are an expensive stumbling block to full-scale green car production. “The challenge [facing the auto industry is] to reduce both manufacturing and packaging costs,” says Kumar.
One reason for the high price tag is the fact that most of the lithium-ion battery manufacturing infrastructure is currently concentrated in Japan.
That unfair advantage may be about to change, however, thanks to a recently unveiled initiative that intends to help manufacturers in the United States become more competitive. A consortium of battery manufacturers has joined forces with Argonne National Laboratory (Argonne, IL) to form the National Alliance for Advanced Transportation Battery Cell Manufacture. It plans to build a manufacturing and prototype development center in the United States.
“The Alliance hopes to level the playing field,” says Ralph Brodd, a battery consultant based in Henderson, NV. In the not-too-distant future, he believes that batteries will be to green cars what semiconductors were to personal computers three decades ago.
“Other countries are investing heavily in the manufacture of lithium-ion cells,” Brodd points out. “Those countries understand that whoever makes the batteries will one day make the cars.”
Traditionally, lithium-ion batteries have been expensive to produce. They need to be managed electronically to ensure safe, reliable, long-term operation. Lithium-ion battery packs are more complex and require extra assembly steps than other types of batteries, which results in a higher price tag.
For instance, they depend on an elaborate battery monitoring system that measure cells to ensure their optimum interaction. The current inside the batteries is not conducted via cables but along copper bus bars that must be welded.
According to Brodd, the manufacturing process is significantly different for lithium-ion than other types of batteries. “Among other things, it requires more prismatic elements, different cell structures, and flat plates to ensure uniform current distribution and dissipation,” he points out.
Assembling lithium-ion batteries also presents new manufacturing challenges. For instance, they require dissimilar tab materials. "Assembling these batteries requires joining thin aluminum, copper or nickel tabs, often in multiple layers and to thicker (and often dissimilar) interconnects," says Matt Bloss, project engineer at the Edison Welding Institute (Columbus, OH).
Automation is also important to assembling lithium-ion batteries. Brodd has visited several battery manufacturing plants overseas and he says they are all highly automated. “If you don’t use robotics and other automation technology, you can’t compete,” he warns.
Brodd believes the Alliance’s new plant will be built somewhere in the Midwest so that it’s strategically located near Argonne and Detroit. While a site somewhere in southwestern Michigan or northern Indiana would make sense, Brodd says there’s also a strong possibility that the facility could be built in Kentucky, which has become the epicenter of the domestic auto industry in the 21st century.
No matter where the facility is built, the state of Michigan is already making a major push to become ground zero for battery R&D and manufacturing in North America. “We are at a critical junction in the commercialization of advanced battery technology to power the next generation of green vehicles,” says Senator Carl Levin (D-MI). “We must be in the position to produce the essential components in the U.S. and not rely on advanced technology and critical building blocks produce elsewhere and brought to the U.S. for assembly.”
Jennifer Granholm, Michigan’s governor, recently signed legislation that encourages companies to develop and manufacture advanced batteries in her state. In fact, House Bill 6611 earmarks $325 million in tax credits.
A123 Systems Inc. (Watertown, MA) has already announced that it plans to build several world-class lithium-ion battery manufacturing facilities in the United States. Its first assembly plant will be located near Detroit to serve customers such as Chrysler LLC (Auburn Hills, MI).
To supply the new Chevy Volt, GM claims it will become the first automakers to assemble lithium-ion battery packs in the United States. “That will allow them to get more control over the manufacturing process,” says Brodd. “For instance, GM can insert proprietary electronic controls in the batteries.” The plant, which will also be located in Michigan, will ramp up production in 2010 using cells supplied by LG Chem Ltd. (Seoul, South Korea) and its local subsidiary, Compact Power Inc. (Troy, MI).
In addition, Ford Motor Co. (Dearborn, MI) just announced that Johnson Controls-Saft Advanced Power Solutions (Milwaukee) will be the exclusive battery supplier for the plug-in hybrid electric vehicle that it plans to introduce in 2012. The lithium-ion battery packs, including cells, mechanical, electrical, electronic and thermal components, will be assembled in the United States, but no specific site has been announced.
In addition to the new battery manufacturing plants in the Wolverine state, the University of Michigan (Ann Arbor) and GM have teamed up to create a new R&D laboratory. Engineers at the Advanced Battery Coalition for Drivetrains (ABCD) facility will be conducting cutting-edge experiment and simulations to better understand and resolve issues related to battery life and performance.
“Batteries are the most important part of the electric drivetrain, but they haven’t been exhaustively studied in the automotive world because of their limited role in gas-powered vehicles,” says Ann Marie Sastry, codirector of the ABCD facility and a professor of mechanical, biomedical and material science and engineering at the University of Michigan. “Our shared ambition is to see electrified drivetrains in a large number of vehicle types and applications. That means we need to reduce the design cycle in both time and cost."