Ally Winning, European Editor, PSD
There is no doubt that battery technology holds the key to many advances in the industry. Better batteries or other large scale storage systems would allow renewable energy to completely replace fossil fuels. They are also key to longer use times for consumer devices and fighting the stress of battery anxiety. Most importantly batteries are fundamental to the take up of electric vehicles (EVs).
EV owners have a similar anxiety to consumer device users about when batteries will run out. This anxiety is not a great selling point for automotive manufacturers who wish to migrate users to EVs. Batteries employed in today’s EVs also take a relatively long time to charge. The combination of battery anxiety and the thought of long journey delays while recharging puts off a lot of potential EV customers. Users want at least the same experience as they have with internal combustion engine (ICE) vehicles. ICE vehicle drivers wouldn’t want to wait hours to fill up before they can drive to their destination, and EV drivers understandably have the same reluctance.
Researchers from Penn State have been developing lithium iron phosphate batteries to try alleviate these concerns. The new batteries have a potential range of up to 250 miles, can charge in 10 minutes and have a potential lifespan of 2 million miles. In a paper in that was published recently in Nature Energy, the Penn State researchers claim that the long-life of the battery and fast recharging are due to the battery being able to quickly heat up to 60oC when charging and discharging and to cool down quickly when the battery isn’t working.
The new battery has been developed by a team under Chao-Yang Wang. It was designed to take advantage of a self-heating technique that has been developed by Penn State’s Electrochemical Engine Center. The battery’s design has a thin nickel foil that has one end attached to the negative terminal and the other being extended outside the cell to create a third terminal. The flow of electrons quickly heats the nickel foil using resistance heating, heating the internals of the battery in the process. When the internal temperature of the battery gets to 60oC, a switch is opened and the battery can quickly charge or discharge.
The self-heating method allows the use of cheap materials for the battery's cathode and anode, as well as the low-voltage electrolyte. The cathode is manufactured from thermally stable, lithium iron phosphate and anode is made from very large particle graphite. The self-heating negates any concerns about uneven deposition of lithium on the anode, which can cause lithium spikes.
The research was supported the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy and the William E Diefenderfer Endowment.
For more information, check out this Nature.com article.