Battery Future - Growing Markets and Battery Tech DevelopmentAdd bookmark
In 2016, the low oil price continues to hamper the growth of battery-electric vehicle (BEV) and hybrid electric vehicle (HEV) sales, but that’s not stopping auto makers or battery suppliers investing in the future of electrification technologies.
With tougher emissions targets such as the USA’s 2025 CAFE requirements and ultra-low emissions zones in urban areas on the horizon, and the impact of tailpipe emissions on human health back on the radar in the wake of the Volkswagen diesel scandal, vehicle makers have increasing numbers of EVs and HEVs in their product plans.
"As you can see in the market today, sales of vehicles are somewhat depressed, but we haven’t seen any retrenching or changing of commitment to electrification among vehicles that are currently in development," confirms Jeff Kessen, VP of corporate strategy at battery maker, A123 Systems. "Particularly given our strategy of focusing on low-voltage micro-hybrids, where there’s an incremental gain, we haven’t seen any slowing of interest."
Battery makers like A123 Systems are at the heart of vehicle electrification and lithium-ion has established itself as the key chemistry in the automotive market, with different variants for the power cells used in hybrids and the energy cells seen in BEVs. Its inferior energy density has seen Nickel-metal hydride (NiMH) ousted, with the notable exception of Toyota’s 2016 Prius hybrid, which retains a NiMH battery option. In the BEV market especially, Li-ion is now the technology that is delivering the antidote to range anxiety and enabling OEMs like Tesla to offer a 425km range. For the next decade or more, it’s expected that incremental improvements to Li-ion technology to provide greater power density, higher reliability and better temperature stability will shore up its leadership position.
"Most of the lithium-ion batteries that are in vehicles today have metal-oxide cathodes and graphite anodes," explains Mike Duhaime, global director for electrified powertrain propulsion systems at Chrysler. "But as we work through the different chemistry pieces to get more energy-dense batteries and to try to manage the cost, we are seeing a lot of focus on using silicon or silicon alloys to replace or mix into the traditional graphite anodes."
Duhaime adds that the potential for energy density improvements has been documented by the research, but the expansion of the anode during charging causes a lot of stress on the materials and leads to reduced cycle life. Clearly there’s more development to do in this area before production applications can be considered.
"Looking further ahead, especially for the energy batteries [used in BEVs], there’s work being done on solid-state electrolytes that’ll make the batteries smaller, more efficient and lower cost," he continues. "We’re able to get the dendrite growth down [with solid-state] so it keeps the longevity and we can use the battery more to its full potential. Solid-state certainly has some promise if the developments continue."
It took Li-ion more than a decade to migrate from small, consumer-electronics applications to mainstream automotive use. Now startup companies such as Oxis Energy (lithium-sulfur, Li-S) or Faradion (sodium-ion, Na-ion) are working to commercialize alternative battery chemistries. However promising, these developments will most likely also have to prove themselves in other fields, such as stationary energy storage, before traditionally conservative auto makers consider them ready for vehicle applications.
As BEV and HEV volumes grow, it might not just be the cells themselves that are manufactured by the battery suppliers, as is typically the case at the moment.
"I think the OEMs that were already making packs will continue to use that investment, but as you get to higher volumes I think the cell manufacturers, at least the leading ones, will start to manufacture packs themselves," says Duhaime. "That will give us some advantages in not having to transport the cells – we’ll just get a pack in the shape that we want. But as we look at industry trends, I still think the controls and battery management will remain with the OEMs because that’s really the character of the vehicle, the heart of the system."
Pack assembly is just one of the ways in which the relationship between OEMs and battery suppliers could change. EV batteries are still too important to the vehicle to become a commodity item, but there are signs that but the battery product category is evolving to be more like the customer-supplier relationship typical of other important vehicle components, according to A123’s Kessen.
"We’re in a phase where the battery industry is maturing as a supply base and volumes are starting to come up," he says. "I see auto makers starting to develop multiple competitive sources, whereas previously you would see each OEM allied with one specific battery manufacturer. Today you’re beginning to see programs getting dual-sourced. You’re starting to see OEMs developing a portfolio of suppliers in their supply base rather than focusing on co-development with a single company."
Tesla’s deal with LG Chem to provide service batteries for the Roadster is one example – the Californian auto maker had previously been wedded entirely to Panasonic’s quite different cell design, chemistry and packaging. Meanwhile Audi has announced that both LG Chem and Samsung SDI will supply battery cells to its forthcoming pure-electric SUV. It’s not known whether cells from the two suppliers will be combined, interchanged or used separately, however.
Obtaining equivalent performance from rival battery makers’ technologies is a countervailing force that’s moderating the dual-sourcing trend, according to Kessen. "It depends on the level of interchangeability you want to have," he expands. "In Germany, there have been efforts under the VDA consortium to standardize cell dimensions so that an OEM can buy a comparable cell and put it into their own battery pack. But if the chemistry isn’t close, standardizing on the physical dimensions necessarily yields a different sort of performance."
Duhaime, too, exercises a note of caution: "Some of the suppliers specialize in pouch cells, others the prismatic cells, which have a different makeup. If an OEM had two suppliers of one type, maybe that would be OK, but you’d be hard pressed to be sure that those two suppliers had exactly the same recipes to make them interchangeable. You could do it across different model years, but not for the same vehicle in the same year. However, we have looked at two suppliers where it’s for a hybrid and a plug-in hybrid – two different [types of] cells in the same vehicle."
A growing market
LG Chem has been revealed as the battery supplier to Chrysler’s new Pacifica plug-in hybrid (PHEV) and will also supply perhaps this year’s highest profile new BEV, the Chevrolet Bolt. Panasonic remains deeply embedded in Tesla’s growth, both with the Model X SUV and the Gigafactory project, which the auto maker hopes will make a major dent in battery costs as production ramps up. Samsung SDI revealed the prototype of a new, high-energy-density battery cell for EVs at the Detroit auto show in January. And the development and validation of A123 Systems’ improved nickel/manganese/cobalt (NMC)-based Li-ion cells continues to make good progress, according to Kessen.
In short: there’s a lot happening in the automotive battery market, with further growth in volume and technology a certainty for the next decade. With major new players such as Porsche’s Mission E set to expand the sector in the coming decade, it’s a great time to be a Li-ion cell manufacturer…