RESEARCH ANALYSIS: Advanced automotive batteries
Higher volumes for batteries are key to lower cost
For some time, manufacturers have been pushing back the technical boundaries of batteries used for hybrid electric vehicles. Matthew Beecham asks executives of three leading advanced battery makers - Western Lithium, GS Yuasa and Axeon - for their opinions on how this blossoming market is shaping-up.
It appears that lithium-ion batteries are well suited to electric vehicles in respect of high energy content. What further advances could we expect with this technology for automotive applications?
“The Nissan Leaf that I am currently driving,” said Jay Chmelauskas, President, Western Lithium USA Corporation, “has a lithium-ion battery with a range that is more than adequate for the bulk of my commute and general activities as a family of four living in Vancouver. We expect two technological advances with batteries in the next generation of vehicles. First, improved manufacturing technology to reduce the cost of production and thereby support larger batteries in vehicles to extend range. Secondly, improved chemistry and design of both the cathode and anode to increase energy density, thereby extend range and possibly reduce charging time.”
“There are several other key areas that li-ion materials and cell engineering are trying to address,” added Dr Allan Paterson of Axeon. “These include increased power density, more efficient systems, cells that are easier to thermally manage, better lower temperature performance, more stable cell chemistry that leads to long cycle life and improved cell level safety.”
While the cost of lithium-ion batteries for electric cars is falling, there is some way to go. As we understand it, the cost of such batteries is approximately US$600 per kilowatt hour compared to US$250 per kilowatt hour for laptop batteries. Can batteries for electric vehicles get that low?
“It is possible by 2020 that EV battery prices can reach this level but it is dependent on large volumes, i.e. 150,000 units per annum of a single design to be realized,” said George Peterson of Axeon. “If EVs still remain a niche then prices could struggle to get below $400/kWh.”
Chmelauskas expects the automotive sector to follow a similar price decline for larger scale automotive lithium-ion batteries due to economies of scale, innovation and competition.
Yet whichever way you look at it, EVs remain expensive despite government grants being offered (here in the UK) yet still give motorists range anxiety with just 100 miles between charges. What needs to happen to EV batteries to improve this situation?
Dr Paterson believes that cost competitiveness versus an ICE equivalent is always going to be a challenge. “The largest proportion of battery pack cost is the cells. Mass production and the development of lower cost materials will help drive down cost, as will cell format standardization. The second largest constituent is the electronics, battery management system and high voltage electronics, but again volume production, standardization etc will bring costs down. However, even give these developments there will remain a limit to the $/kWh price that batteries will be sold at for some time into the future until a materials chemistry development enables a step change in performance and cost. EVs are ideal for city cars, small commutes etc, the use of Plug in HEV and Range Extended Li-ion based battery packs for next generation of mainstream automotive vehicle will be a significant development building upon the Gen I vehicles such as the GM Volt etc.”
Masato Furumi, General Manager, Business Promotion Department, Automotive Battery Business Promotion Division, International Business Unit, GS Yuasa International Ltd, points out that energy density of large Li-ion battery is around 100Wh/kg now, while that of small Li-ion battery for home appliances is 200Wh/kg. “Many large Li-ion batteries are packed for automotive application, so their heat must be well regulated during charge and discharge. Their energy density is deliberately lower to keep heat emission under control through physical and chemical means. As technology progresses further, more suitable heat control for higher energy-density batteries will be developed and range between charges of EV will consequently increase. “
“As a Nissan Leaf owner,” concludes Chmelauskas, “range anxiety is quickly forgotten and the positive attributes of a clean, cheap, smooth, fast, quiet driving experience generates tremendous satisfaction for the driver. That makes any preconceived ideas a moot point. With the energy savings on gasoline, improved driving experience and other characteristics such as never needing to go to a gas station, the value of an electric car can be justified for many drivers.”