Cold weather can be the bane of battery-powered electric vehicles. The issue made headlines two winters ago in a dispute between Tesla’s Elon Musk and a New York Times reviewer. Whatever the merits of the Tesla vs. Times arguments, lithium ion batteries do lose capacity at low temperatures.
Now, however, researchers at Penn State and EC Power (based in State College, PA) are attempting to alleviate range anxiety through the development of a Li-ion battery that self-heats at temperatures below freezing.
“It is a long-standing problem that batteries do not perform well at subzero temperatures,” said Chao-Yang Wang, director of Penn State’s Electrochemical Engine Center, as quoted in Newswise. “This may not be an issue for phones and laptops, but is a huge barrier for electric vehicles, drones, outdoor robots and space applications.”
Wang, who is also the William E. Diefenderfer Chair of mechanical engineering, a professor of chemical engineering, and a professor of materials science and engineering, also said, “We don’t want electric cars to lose 40 to 50% of their cruise range in frigid weather as reported by the American Automobile Association, and we don’t want the cold weather to exacerbate range anxiety. In cold winters, range anxiety is the last thing we need.” Cold weather can also restrict regenerative-braking performance.
Wang and fellow researchers said they are relying on previous patents by EC Power to develop the all-climate battery, designed to transition from -4 to 32°F within 20 seconds and from -22 to 32°F in 30 seconds and consume only 3.8% and 5.5% of the cell’s capacity.
The all-climate battery uses a nickel foil of 50-μm thickness with one end attached to the negative terminal and the other extending outside the cell to create a third terminal. A temperature sensor attached to a switch causes electrons to flow through the nickel foil to complete the circuit, rapidly heating the nickel foil through resistance heating to warm the inside of the battery. Once the battery is at 32°F, the switch turns off, and the electric current flows in the normal manner.
“Next we would like to broaden the work to a new paradigm called SmartBattery,” added Wang. “We think we can use similar structures or principles to actively regulate the battery’s safety, performance, and life.”
In related news, Ford is testing its autonomous vehicles in snow.