Published on January 21st, 2016 | by Tina Casey24
All-Climate EV Battery Range Extender Goes From -22 to 32F In 30 Seconds
January 21st, 2016 by Tina Casey
Did you know that conventional lithium-ion electric vehicle batteries can lose 40 percent of their capacity in cold weather? That’s an extreme example, but capacity loss during cold outdoor temperatures is a big issue for electric vehicles. Not to worry — it looks like researchers at Penn State University are on to a cure that could enable EV owners to warm up their cars to optimal battery conditions in a matter of seconds and keep them there, with only a minor loss of capacity.
Cold Weather And EV Battery Range
The basic challenge is one that is common among older gasmobiles, which require a longish period of idling after starting up in cold weather, in order for the engine to operate efficiently. That problem has long been solved by gasmobile manufacturers, but EV battery design is still playing catch-up. EV batteries have an optimal operating range, so if your EV has been sitting for a while in cold weather, you need to expend some amount of capacity to warm it up, to keep it warm while driving, and to keep yourself comfortable as well.
With a ripple effect of reducing the input from regenerative breaking, the result can be a loss of 40 percent in EV battery range or even more, according to Penn State researchers.
Last year our sister site Gas2.org passed along some cold weather driving tips for EV owners, courtesy of BMW i3 blogspot, which emphasize that cold weather driving involves some degree of careful planning and foresight because of the drain on battery capacity.
A New York Times reporter notoriously found that out the hard way right around this time in 2013, when he attempted a long distance drive in a Tesla from New York City to Boston in the dead of winter.
The episode evoked a thunderstorm of disapprobation from Tesla Motors owner Elon Musk, as it appeared that the reporter deliberately failed to observe common sense, but it gave CleanTechnica a chance to point out that the real issue is the cost of EV batteries.
Coincidentally, 2013 was also the year that President Obama’s EV Everywhere initiative took on the issue of EV affordability with a whopping $45 million round of funding for EV tech, including improved EV batteries.
In October 2013, Penn State announced that it received a piece of the EV Everywhere pie, in the form of a $3 million grant that teamed it up with the lithium-ion battery company EC Power and these other folks:
The two-year grant from the DOE’s Vehicle Technology Office supports the project “High Energy, Long Cycle Life Lithium-ion Batteries for PHEV (plug-in hybrid electric vehicles) Applications.”
Penn State serves as the main principal investigator (PI) on the grant, with the University of Texas at Austin and Lawrence Berkeley National Laboratory as co-PIs. Also partnering on the grant is the Argonne National Laboratory and industrial power products firm EC Power.
That’s some pretty fancy firepower, right?
EV Batteries Warm Up From -22 To 32 In Seconds
That brings us right around to the new EV battery warmup solution from Penn State and EC Power.
The team started with existing patents from EC Power and developed an “all-climate” lithium-ion battery that incorporates a thin (50 micrometers) foil of nickel. One end is attached to the negative terminal and the other goes outside the cell, effectively creating a third terminal.
With an assist from a temperature sensor, electrons automatically flow through the nickel foil when the battery temperature drops below 32 degrees Fahrenheit. That translates into heat for the foil, which flows into the innards of the battery. The heating system automatically shuts itself down once the battery temperature achieves 32 degrees.
While the new battery would weigh (and cost) slightly more than one without the nickel foil system, the numbers work out much better in terms of range extension, and the system practically eliminates the need for an extended warmup time:
The researchers, relying on previous patents by EC Power, developed the all-climate battery to weigh only 1.5 percent more and cost only 0.04 percent of the base battery. They also designed it to go from -4 to 32 degrees Fahrenheit within 20 seconds and from -22 to 32 degrees Fahrenheit in 30 seconds and consume only 3.8 percent and 5.5 percent of the cell’s capacity.
You can get all the details on the new all-climate EV battery from the journal Nature, under the somewhat modest title “Lithium-ion battery structure that self-heats at low temperatures.” The authors note that in addition to EV batteries, the new system could prove useful for robotics and space exploration.
EV Everywhere: Thanks, Obama
The research team also notes that a number of other materials could work as well as nickel, but the idea was to focus on the least costly material that could do an effective job, a goal supported by EV Everywhere. It’s quite possible that some auto manufacturers would go for the most efficient material regardless of cost, depending on whether or not affordability is a critical issue for their customers.
With that in mind, let’s catch up on EV Everywhere. The initiative is designed to make EV ownership just as affordable and convenient as owning a gasmobile, and it looks like things are heading in the right direction.
In addition to EV battery research, EV everywhere includes lightweighting initiatives to extend battery range…
…and one of our favorites, the Workplace Charging Challenge: