AUTONEWS
Physical pressure could make EV batteries last twice as long and reduce environmental impact
Electric vehicle batteries could last more than twice as long if they are assembled in away to control the pressure inside them more accurately, according to new research published (Monday 29 June).
The team discovered that keeping batteries under the right amount of pressure as they charge and discharge significantly slows the damage that causes them to lose capacity over time.
The findings could one day mean fewer phones are thrown away only because their batteries no longer hold enough charge, while also helping electric cars and renewable energy storage systems last longer.
Heng Wang, first author of the study published in Nature Energy, and a postgraduate student at St John's College and the University of Cambridge's Department of Engineering, said: " Much of today’s battery research focuses on improving materials and chemistry.
“We've shown that simply controlling how the battery is compressed can have a huge impact on how long it lasts. That could help manufacturers build batteries that last much longer without fundamentally changing what's inside them."
Researchers led by the University of Cambridge studied the role of physical pressure on the lifetime of lithium-ion batteries and found that keeping batteries under constant pressure could double their lifespan.
Such gains are unheard of in battery development, where tweaks to battery composition usually result in gains of five to 10 percent. Extending the lifetime of electric vehicle (EV) batteries would not only reduce the rate at which they end up in landfill or recycling, but would also reduce the environmental pressures associated with nickel or cobalt mining.
Applying the right amount of physical pressure to lithium-ion batteries could double their lifespan, reducing battery waste and easing demand for critical minerals used in electric vehicles, according to a study led by researchers at the University of Cambridge.
The study released on Tuesday suggests that extending battery life may not require new materials or complex chemical innovations, but rather a carefully controlled mechanical design that maintains consistent pressure on batteries throughout charging and discharging cycles.
"Batteries don't tend to like this cycle of stress and release," said Professor Michael De Volder from Cambridge's Department of Engineering, who co-led the research.
"Much of the work on improving lithium-ion batteries is done by chemists and physicists, but as a mechanical engineer, I also wanted to look into the role that mechanics play," he said.
Lithium-ion batteries naturally expand and contract as lithium ions move between the anode and cathode during charging and discharging. According to the researchers, these repeated volume changes generate mechanical stress that gradually damages battery components and shortens battery life.
To investigate the effect of pressure, the research team developed a laboratory device that uses pneumatic bellows-small air-filled cushions-to apply a constant pressure to commercially available pouch-cell batteries. Sensors continuously monitored tiny changes in battery volume during operation.
The researchers found that the pressure must remain within the "Goldilocks" zone of about 12.5 bar. Higher pressure can cause lithium plating to form on the anode, while lower pressure can cause the cathode to crack, both of which shorten battery life.
"We found that when you keep the pressure on them relatively constant throughout each charge and discharge cycle, it's much better for the overall lifetime of the battery," De Volder said.
The technology has been tested at a laboratory scale and will require further development before it can be applied in commercial battery applications.
However, the pressure needs to be just right – too much or too little will cause the batteries to fail. The researchers built a custom device to keep the pressure on the battery in this ‘Goldilocks’ zone, without the need for any specialised chemistry. Their results are reported in the journal Nature Energy.
At their most basic level, lithium-ion batteries are composed of an anode, a cathode and an electrolyte. As the battery goes through each charge and discharge cycle, lithium ions shuttle from the anode to cathode and back again. This causes the battery to physically expand and contract, almost like breathing.
“Batteries don’t tend to like this cycle of stress and release,” said Professor Michael De Volder from Cambridge’s Department of Engineering, who co-led the research. “Much of the work on improving lithium-ion batteries is done by chemists and physicists, but as a mechanical engineer, I also wanted to look into the role that mechanics play.”
To study this, De Volder and his colleagues built a device that squeezes a type of battery known as a pouch cell using pneumatic ‘bellows’: small air-filled cushions that act like a self-adjusting clamp. The bellows maintain a continuous pressure, while a sensor monitors tiny volume changes as the battery charges and discharges.
“We just bought commercial batteries and tested them for lifetime under different pressures,” said De Volder. “We didn't have to change anything about their electrolyte or electrode composition.”
They found that the pressure from the bellows needs to be in the ‘Goldilocks’ zone: about 12.5 bar, or roughly four times what’s standard in conventional coin cell batteries. Outside this zone, the batteries fail faster. If the pressure is too high, it can cause lithium plating to form on the anode, and too little can cause the cathode to crack.
“We found that when you keep the pressure on them relatively constant throughout each charge and discharge cycle, it’s much better for the overall lifetime of the battery,” said De Volder. “If you press too hard, the anode is unhappy. If you don't press hard enough, the cathode starts degrading. Our experiments identified where the ‘happy place’ is for batteries when it comes to pressure.”
The results, while early stage, could have important implications for the fast-growing EV market, especially in the second-hand market. “The longer your product will last, the fewer the number of times you’ll have to recycle the materials,” said De Volder. “And we are very bad at recycling batteries at the moment.”
In addition, longer-lasting EV batteries could reduce the volume of raw materials that need to be mined, often in extremely poor conditions, to produce new batteries. “We’ve produced a solution for cleaner electric cars, but we have to make sure that on the back of it, we are not creating new ecologic disasters in other parts of the world,” said De Volder. “If we can reduce the pressure on these mining operations a bit, that would be another important benefit.”
The technology has been tested at a laboratory scale, but will need to be scaled up for commercial battery applications. A patent has been filed by Cambridge Enterprise, the University’s innovation arm.
The research was supported in part by the European Research Council, the Faraday Institution, and the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation (UKRI).
Michael De Volder(St John’s College, Cambridge)



