Shaping the Future of Green Cars
Nissan engineer Taehee Han is leading the company’s effort to build a better EV battery.Like all automakers, Nissan Motor Co. wants to build a better electric car battery, so that the world will beat a path to its door.
And Nissan engineer Taehee Han is the point man in the company’s effort. Han heads a staff that includes 10 PhDs – chemists, materials scientists, and chemical engineers – who have put the company at the front of EV business by keeping their battery effort in house.
“We are not only assembling EVs, we’re manufacturing batteries and motors and all the parts necessary to make EVs,” Han told Design News. “We basically make everything here from scratch.”
Indeed, Nissan is unusual in its use of so-called “vertical integration.” Unlike General Motors, which uses battery cells designed by LG Chem, and Tesla, which employs a Panasonic design, Nissan has stuck with an in-house approach that even skeptics would have to concede has yielded great results. To date, the company has sold more than 250,000 all-electric cars, making it the industry leader. Moreover, none of those vehicles have suffered a major battery-overheating problem.
|Nissan engineer Taehee Han is leading the company’s effort to build a better EV battery. (Source: Nissan Motor Co.)|
“We have zero fire incidents,” Han told us. “Our battery is so safe, even the Chinese government uses it as a reference for their stringent abuse tests.”
Han says the company’s safety record is partially a result of its vertically integrated approach, and partially the product of a concerted safety effort. Material scientists are directed to use the safest possible materials, he said, while pack and vehicle designers are careful to enclose the battery in a way that protects it. “If there’s a catastrophic collision, our battery pack will be safe,” Han said.
At the same time, Nissan continues to drive down costs, while searching for ways to reduce recharge times. Like most automakers, it is following the long-time lead of the United States Advanced Battery Consortium (USABC), which continues to aim for a cost target of $100/kWh. But Nissan also keeps its own numbers in mind. “Our internal target is lower than that,” Han said. “Always lower.”
Han added that the EV’s all-electric driving range is reaching the point where it’s less of a concern than recharge time. “Even though we can drive 300 miles with a huge pack, we still have to wait an hour-and-a-half to charge up,” he said. “Some customers are not going to like that, so we need to develop quick charging.”
Such concerns are not what Han originally imagined for himself while growing up in South Korea. After earning a B.S. in mechanical engineering there, however, he became fascinated with green energy and moved to the U.S. to study wind turbines, ultimately earning an M.S. in engineering at Texas A&M University. A PhD in energy engineering followed at the University of North Dakota, where he took a special interest in hydrogen fuel storage. At that point, Han saw himself working for an electric utility or an energy company. But fate interceded again when his background in fuel cells landed him a position in the auto industry at Nissan.
Han’s circuitous route to automotive battery engineering is really just a classic case of cross-pollination, he said. “Even though my disciplines were mechanical engineering and energy engineering, I never lost my interest in green energy,” he told us. “As a high skill engineer, you always need to know other disciplines in order to develop something new and better.”
Ultimately, batteries offer the same kind of green potential as wind turbines, and that satisfies Han. “A great energy future is one of my dreams,” he said. “And I think it’s possible.”
Cutting the Cost of Hydrogen Fuel Cells
GM fuel cell engineer Sara Stabenow wants to bring hydrogen-powered cars to production in the near future.
GM engineering group manager Sara Stabenow: “Every person who has visited our lab has been surprised. They always say, ‘We didn’t know you were this close to manufacturing.’” (Source: General Motors)
Sara Stabenow’s dream is to capture the unused energy from spinning wind turbines, run it through electrolyzers, and produce millions of gallons of cheap hydrogen fuel.
And when that era of cheap, plentiful, hydrogen fuel arrives, Stabenow will be ready. As an engineering group manager for General Motors’ fuel cell program, she’s already working on lower-cost fuel cells for automobiles. Next-generation fuel cells will be a fraction of the size and cost of what’s available today, she says, and will be capable of going head to head with battery-based powertrains in electric cars, as long as the hydrogen is available.
“Both have their advantages, but the fuel cell has an advantage of a very quick refill,” Stabenow told Design News. “To fill a hydrogen tank takes minutes. It’s very comparable to a conventional internal combustion car, whereas the battery has a very long recharge time.”
Indeed, the practical business case for fuel cells is emerging with greater clarity than ever before. In January, GM and Honda announced the auto industry’s first manufacturing joint venture to produce hydrogen fuel cells. The two automakers have already made equal investments totaling $85 million in the joint venture, and plan to start mass production of the fuel cell packs by 2020. In the process, they’ve already accumulated more than 2,200 patents between them.
Stabenow says that the oft-repeated claims of costly fuel cell stack are old news. One of the big cost factors – the presence of ultra-expensive platinum in the catalysts – is changing. Over the past 10 years, platinum content has dropped from 90 g to 40 g to 15 g in three generations of fuel cell products, she said.
“Going from 90 to 15 g of platinum in 10 years is a dramatic reduction,” she told us. “That translates very quickly to actual dollars.”
The cost reductions are raising hopes inside GM, which built its first fuel-cell-powered vehicle, the 7,100-lb Electrovan, back in 1966. Stabenow said that GM material scientists have also cut the cost of the plates used in the stack by employing a lower-cost grade of stainless steel. The goal is to combine those lower material costs with the economies of scale of a high-volume manufacturing plant, and drive the expenses down even further.
“We’re vetting that technology very early,” Stabenow told us. “So we are able to ‘trial’ it on actual manufacturing-intent equipment to show that this stuff can be made.”
Moreover, GM has moved its fuel cell program team from New York to Pontiac, MI to be closer to the company’s engine and transmission programs, the better to capitalize on knowledge in those quarters. Ultimately, the company plans to bring its technology out in a production car, but it’s not yet saying when.
None of this is unfamiliar territory for Stabenow, who holds an M.S. in materials science from Ohio State University, served as a metallurgical engineer at GM’s Flint transmission plant and, later, as an engine materials engineer at GM’s Livonia engine plant. She has also held senior roles in manufacturing, giving her a practical view of production realities.
That’s partly why she’s convinced that there’s an important role waiting for fuel cells in the near future. “This isn’t a science project,” she told us. “Every person who has visited our lab has been surprised. They always say, ‘We didn’t know you were this close to manufacturing.’”
Senior technical editor Chuck Murray has been writing about technology for 33 years. He joined Design News in 1987, and has covered electronics, automation, fluid power, and autos.