Cambridge experts have discovered a remarkably straightforward solution for prolonging the lifespan of EV batteries: just apply some pressure.
Researchers have discovered a method to extend the lifespan of electric vehicle (EV) batteries without the need for completely new technology. A study from the University of Cambridge shows that applying the right amount of pressure to batteries can effectively enhance their longevity.
The research explored the effects of physical pressure on lithium-ion battery lifespan, revealing that maintaining a consistent pressure could potentially double the lifespan of battery cells. This study was published in Nature Energy, and the authors note that these improvements were achieved without altering the active materials, electrolyte, or fundamental battery chemistry.
How does pressure enhance performance?
Lithium-ion batteries expand and contract physically during charging and discharging, a process that Cambridge likens to breathing. Over time, this repetitive mechanical stress can lead to degradation within the battery cell. To investigate this, the researchers designed a specific apparatus that applied consistent pressure to lithium-ion pouch cells using pneumatic bellows, which function like self-regulating air cushions. This setup also monitored minor changes in the thickness of the battery throughout its cycle.
A crucial discovery was the identification of an optimal pressure range. At approximately 12.5 bar, or around 181 psi, the cells demonstrated a lifespan about twice as long as those tested under lower or higher pressure conditions. While it can be summarized as preventing the battery from "breathing," it doesn't imply that every EV battery needs to be crushed for optimal results. The pressure must be carefully controlled.
Why too much or too little pressure is detrimental
The study revealed various failure modes based on the applied pressure. Low pressure led to accelerated cracking of the cathode, while excessive pressure caused lithium plating on the anode, which negatively affects battery life and safety. Therefore, there is a challenge of finding the right balance. EV batteries can indeed benefit from being maintained under optimal mechanical conditions; however, the system must consistently manage the pressure as the battery expands, contracts, ages, and changes shape.
This research presents an intriguing approach. Instead of focusing on chemistry and other aspects, it examines the problem from a mechanical design angle. The research is still in its early stages and has only been conducted in a laboratory setting, so this technology won't be integrated into next year's EVs immediately. Cambridge has applied for a patent through Cambridge Enterprise, and the next step is to determine how to implement this pressure-control concept into commercial battery packs.
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Cambridge experts have discovered a remarkably straightforward solution for prolonging the lifespan of EV batteries: just apply some pressure.
Researchers from Cambridge discovered that by applying the appropriate constant pressure to lithium-ion battery cells, their lifespan could be doubled without altering the chemistry.
