If you're concerned that electric vehicles don't have the reliability to get you where you need to go, Penn State engineers are working on a battery for you.
The researchers' lithium iron phosphate batteries have a range of 250 miles, with the ability to charge in 10 minutes.
According to the report in Nature Energy , the battery's long life and rapid recharging are due to its ability to thermally modulate. The battery quickly heats up to 140 degrees Fahrenheit, for charge and discharge, and then cool downs when the battery is not working.
"The very fast charge allows us to downsize the battery without incurring range anxiety," said Chao-Yang Wang , William E. Diefenderfer Chair of mechanical engineering, professor of chemical engineering and professor of materials science and engineering, and director of the Electrochemical Engine Center at Penn State.
Range anxiety, or the fear that a vehicle will lack the charge required to reach a destination, could be eased with a battery that self-heats.
The results of the thermally modulated, or "TM" technology, were reported in a January 2021 journal of Nature Energy .
The self-heating battery, developed in Wang's center, uses a thin nickel foil with one end attached to the negative terminal and the other extending outside the cell to create a third terminal.
As electrons flow, the battery rapidly heats up the nickel foil through resistance heating and the internal warmth of the battery. Once the battery's internal temperature is 140°F, the switch opens and the battery is ready.
With a self-heating method, low-cost materials can be used for the battery's cathode and anode, says Wang.
The cathode is a thermally stable, lithium iron phosphate, which does not contain any of the expensive and critical materials like cobalt. The anode is made of very-large-particle graphite — a safe, light and inexpensive material.
The self-heating approach also reduces uneven deposition of lithium on the anode, which can cause lithium spikes that are dangerous.
According to Wang, the smaller batteries produce a large amount of power upon heating — 40 kilowatt hours and 300 kilowatts of power. An electric vehicle with this battery could go from zero to 60 miles per hour in 3 seconds and would drive like a Porsche, the professor.
"This is how we are going to change the environment and not contribute to just the luxury cars," said Wang. "Let everyone afford electric vehicles."
In an interview with Tech Briefs below, Dr. Wang explains how he'll work with battery manufacturers and automakers to put more electric vehicles on the road.
Tech Briefs: What has prevented lithium iron phosphate batteries from being used in a mainstream way?
Dr. Chao-Yang Wang: Lithium iron phosphate (LFP) batteries have slightly lower energy density than nickel-cobalt-manganese (NCM) or nickel-cobalt-aluminum (NCA) batteries; as such, LFP batteries have not been widely used in electric cars that have been designed to carry big batteries in order to overcome consumer’s range anxiety. LFP batteries were too heavy if vehicle batteries are big.
Tech Briefs: In a news release from Penn State , you said you developed a “clever” battery. What makes the design clever, and how is it a different design from conventional battery designs?
Dr. Chao-Yang Wang: We took an opposite approach to invent 10-minute fast, convenient recharge. In turn we can use a small vehicle battery, such as a 40 kWh one, without worrying about range anxiety. The smaller the battery, the lower cost.
On top of that, because of a small battery on board, one can now use a lithium-iron phosphate material that is further cheaper than NMC or NCA. So we achieved double-saving in cost, a smaller battery for lower cost overall and a cheaper LFP material for lower unit cost.
The 10-min, fast-recharge LFP battery is enabled by a thermal modulation strategy. We always pre-heat the TM battery to ~60 deg C before driving or charging and do so rapidly (in 30-60 seconds). The TM battery will naturally cool down when it is not in use or the vehicle is shut down.
The elevated temperature operation significantly improves efficiency and permits 10-min fast [recharge], which would be otherwise not possible at room temperature. Simultaneously the elevated temperature operation offers huge discharge power, i.e. 300 kW for a 40kWh pack, which is enough to accelerate a car from 0-60 miles per hour in 3 seconds.
You can see that rapid heating — raising battery temperature by 100 °C per minute — is the key; otherwise it is impractical.
Tech Briefs: What needs to happen next for this kind of battery to be used throughout the electric vehicle market?
Dr. Chao-Yang Wang: We would encourage giga-factory battery manufacturers and automakers to partner with us to implement and demonstrate this TM battery technology in cars and then enter the marketplace.
Tech Briefs: What is it about the design that enables such a long lifetime?
Dr. Chao-Yang Wang: Our TM battery design uses thermally extremely stable LFP cathode and big-particle graphite anode, the latter of which is also more stable and less degrading than conventional graphite used in regular lithium-ion batteries.
Tech Briefs: How does the design address range anxiety? Can’t the battery still run out of power?
Dr. Chao-Yang Wang: The 40kWh TM battery will have a 200-mile range, but it can be readily extended by a 10-minute convenient recharge. (A 10-minute stop would offer opportunities for a restroom visit or coffee break).
So there should be no range anxiety. It is like driving a gasoline car; even when there is only 20 miles left, we don’t feel nervous as long as there is ubiquitous, fast refill available. In that case, we rarely need a 50-gallon gas tank. So the same thing will happen to electric cars.
By the way, our 40kWh TM battery needs only 240 kW charging power for a 10-min energy refill. So, all existing Tesla superchargers, V3 rated at 250 kW, would do the job. In fact, we could increase revenue for Tesla superchargers, because they currently can only do 1 Tesla car per hour. [If you have] 6 TM Battery cars per hour, [you can] increase the revenue of each charger by 6x without incurring additional installation or capital cost.
Other Penn State researchers working on this project were Xiao-Guang Yang, assistant research professor of mechanical engineering, and Teng Liu, doctoral student in mechanical engineering.
The U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy and the William E Diefenderfer Endowment supported this research.
What do you think? Can this battery eliminate "range anxiety?" Share your questions and comments below.