New EV battery could cut costs, end ‘range anxiety’ — study

Source: By Miranda Willson, E&E News reporter • Posted: Thursday, January 21, 2021

A battery that regulates its own temperature could hold the key to the development of fast-charging electric vehicles that cost less than most new gas-guzzling cars.

Researchers at Pennsylvania State University say they have developed an EV battery that achieves that cost milestone, potentially opening up the door for more widespread EV use across the country. The battery also solves another issue reported in some EVs: Even in subfreezing temperatures, the researchers’ “thermally modulated” lithium-ion battery can charge within 10 minutes without compromising the battery life, according to the study published this week in Nature Energy.

Rapid charging of electric cars has caused some lithium-ion batteries to degrade over time, making the batteries increasingly unstable (Climatewire, Aug. 5, 2020). The phenomenon, known as lithium plating, is more common when the weather is below freezing, some research suggests.

The cold-immune battery system developed by the Penn State team is low-cost, having the potential to bring down the retail price of EVs to $25,000, the study said. New electric cars on the market today typically cost over $30,000.

Lithium-ion batteries often have built-in management systems that slow the charging process when it’s cold outside to reduce plating and degradation, according to 2018 research from the Idaho National Laboratory. As a result, charging in northern regions of the U.S. is noticeably less efficient, the lab study said. That could hold back EV adoption in those areas, especially for taxi or rideshare drivers who may need to charge quickly at public stations while on the job.

To achieve fast charging regardless of the climate, the Penn State researchers placed a self-heating structure on a lithium-iron phosphate battery that keeps the system’s temperature at 140 degrees Fahrenheit when the car is moving, said Chao-Yang Wang, corresponding author on the paper and co-director of the Battery and Energy Storage Technology Center at Penn State. Made of an ultra-thin nickel foil, the self-heating structure also cools the battery to the temperature outside when the car is turned off, Wang said.

“[Regardless] of ambient temperature, even as low as minus 30 Fahrenheit, we rapidly heat up the battery around 60 deg. C for operation so we can still charge fast,” Wang said in an email.

In addition to its reliably rapid charging, the thermally modulated battery is more stable and safer than most lithium-ion models, as well as sustainable, Wang said. While the use of cobalt in EVs improves batteries’ energy density, mining for the metal, which mostly takes place in the Democratic Republic of Congo, is associated with questionable labor and environmental practices.

“In a nutshell, we have developed the [thermally modulated] battery for $25,000 electric cars that race like luxury sport cars, have no range anxiety thanks to 10-min convenient rechargeability, are safer than any currently on the market, and use zero cobalt,” Wang said.

The battery could also last for an estimated 2 million miles of driving, according to the study, which would be a major improvement compared with most electric cars today that can typically be driven for up to 200,000 miles. Most likely, a car powered by the thermally modulated battery would retire before the battery had died — meaning it could potentially enjoy a second life for energy storage or another use, Wang said.

The research team hopes to partner with automakers to facilitate the demonstration and commercialization of their battery for next-generation EVs, he added.

Like any new technology, the thermally modulated model could run into technical kinks when scaled up. One battery scientist who did not work on the study questioned whether the high temperature of the battery could shorten its lifetime in practice.

But taken together with other recent innovations in batteries, it could help make EVs cost-competitive with internal combustion vehicles within a decade, said Haresh Kamath, senior program manager of energy storage at the nonprofit Electric Power Research Institute, which was not involved with the research.

“This is an example of some of the innovative thinking that’s happening all the way across the industry that’s helping us reduce costs and some of the challenges that EVs have right now,” Kamath said.

While other scientists have tried to design or discussed the potential benefits of elevated temperatures in batteries, the concept hasn’t been implemented on a wide scale, he added.

“It’ll be interesting to see if this system can be implemented,” Kamath said.