As automakers race to develop electrified vehicles, consumers are balking at the cost of battery-powered powertrains. Continuing advances in battery technologies and electronic controls are going to play a major role in reducing the pricing premium associated with lithium-ion batteries.
The shift to Li-ion will be a key component in this transition, according to panelists in Tuesday’s session on New Battery Technology: The Path to the Best Combination Range, Durability and Cost. The panel was conducted as part of the April 20-23 SAE 2009 World Congress in Detroit.
As in other sessions, the speakers noted that President Obama has championed a drive for 1 million plug-ins by 2015. But they weren’t very bullish about that happening. MY2012 and ’13 vehicles are already in development, with few plug-ins in the pipeline, so availability may not be large enough to reach Obama's target.
The biggest drawback is that there appears to be minor interest from consumers. “It’s possible to achieve [the target], but if the customer pull isn’t there, it will be very difficult,” said Steven Clark, Senior Manager of Electrical/Electronic Energy Management for Chrysler. “You can debate why there would be much pull.”
Hybrids are also losing their luster, as consumer interest in the U.S. fell in conjunction with low fuel prices. “Hybrids now are 2.2 % of the fleet, down from 3.3% last August,” said moderator Nancy L. Gioia, a Group Director at Ford Motor Co.
A key reason for this change is that it’s becoming harder to justify the added expense of batteries. “The current cost of battery technology in low volumes makes it difficult to achieve a two- to five-year payback with $2 gas,” Clark said.
The industry is addressing costs in part by moving from NiMH to Li-ion batteries, which hold the promise of smaller size and ultimately lower costs. Li-ion has more than double the energy density of NiMH, according to Prabhakar Patil, CEO of Compact Power Inc.
“The main things that kept lithium-ion out of hybrids in the early stages were safety concerns and cost. Both have been addressed,” Patil said.
Though Li-ion is widely accepted as the wave of the future, that future is still in the distance. The technology will account for less than half the hybrid batteries in 2014, taking until 2020 to reach 70% penetration, said Michael Crane, North American HEV Managing Director for Continental Corp.
Battery makers and automakers are spending a lot of time making sure that high-voltage battery packs will not cause problems when there are short circuits or during vehicle crashes. “Around 80% of our research goes towards safety,” said Minoru Shinohara, Senior Vice President at Nissan Motor Co. Nissan will unveil electric and hybrid vehicles that use Li-ion batteries next year.
While battery suppliers move to increase their volumes, design engineers are also altering control electronics. More powerful electronics are making it possible to reduce component count.
“The industry is moving to multimodule systems, using one cell supervisory circuit for several batteries,” Crane of Continental said.
Another important factor for electrified vehicles is to convince consumers that they won’t have to replace expensive battery packs. “Customers are going to expect battery warranties that last the life of the car. They won’t want to worry about batteries,” Chrysler's Clark said.
Crane noted that battery lifetimes for hybrids now range from 12 to 16 years. An aging analysis determined that a handful of factors determine that lifetime. Storage temperature when the vehicle is in garage or elsewhere accounts for 40% of aging. Another 20% is related to driving temperature, and driving mode accounts for another 20%.
Having a solid base of battery suppliers in the U.S. is another big factor in the governmental push to promote green vehicles. Panelists noted that battery manufacturing facilities are expensive to build, so government support is warranted. However, they noted that this support could create problems.
“We need to make sure that we don’t get overcapacity that’s caused by government support,” Patil said.