For all the good they bring to our planet, electric vehicles (EVs) are still prone to some issues that hinder their wider adoption and make people steer more towards their gasoline counterparts, including (but not limited to) their batteries catching fire.
Indeed, many potential buyers worry about the safety of EV batteries, and their fears aren’t unwarranted, as just one overheated cell can start a domino effect in which neighboring cells overheat as well and ignite, ending up with a self-sustaining fire that takes ages to put out and is extremely dangerous.
To address this very important problem, researchers at South Korea’s Daegu Gyeongbuk Institute of Science and Technology (DGIST), led by Jae Hyun Kim, Principal Researcher and Professor of Energy Science and Engineering, are starting at the chemistry level, Automotive World reported on May 14.
Addressing EV fires at their origin
As it happens, Kim’s science team has created a breakthrough lithium-metal battery prototype that features a triple-layer solid polymer electrolyte (SPE), which reduces the risk of thermal runaway and suppresses combustion processes.
In particular, the main problem seems to be the formation of dendrites – small, branching structures that sometimes happen during charging and discharging. According to Kim:
“Conventional SPEs suffer from low ion conductivity and poor interfacial contact with electrodes, which promotes lithium dendrite growth and therefore increases the risk of short circuits and fire hazards.”
Hence, the scientists have introduced a triple-layer SPE instead, boasting a robust middle layer mechanically strengthening the battery and a soft outer surface on both sides to secure efficient electrode contact and facilitate the easy movement of lithium ions.
Thanks to this design, energy transfer rates also increase, inhibiting the formation of dendrites. As Kim further explained, this triple-layer structure has reached “mechanical strength, ion conductivity, and fire safety simultaneously – a significant innovation in material design and engineering.”
At the same time, DGIST’s solution can suppress EV battery fires through the use of decabromodiphenyl ethane (DBDPE), a self-extinguishing and flame-retardant additive incorporated into the electrolyte, which releases bromine radicals under high temperatures, and they interrupt the chain reaction of fire propagation, minimizing the risk of thermal runaway accidents.
Elsewhere, others are also trying to overcome this difficult problem. Notably, Hyundai Mobis last month unveiled its new EV battery that not only prevents heat from transferring to nearby cells but also puts out a fire early by spraying an agent within five minutes of the initial ignition.
Meanwhile, others – including researchers at Princeton University in New Jersey – have suggested phasing out traditional lithium-ion batteries altogether and replacing them with a high-energy sodium-ion cathode, which may outperform them and offer a safer, more sustainable, and cost-effective alternative.
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