Stanford develops fire-resistant membrane for Li-ion batteries

The American Stanford University has developed a membrane that sits between the positively and negatively charged sides of a battery and has a fire-resistant function. A battery could not catch fire with this and the addition does not limit the capacity of the battery.

The membrane, which is made of triphenyl phosphate, is coated with polyvinylidene fluoride. When the membrane becomes part of a possible ignition, it can counteract this in 0.4 seconds. The shell prevents the release of the triphenyl phosphate unless ignition occurs and the temperature of the substances rises to 160 degrees Celsius, the melting point of polyvinylidene fluoride. If the triphenyl phosphate could mix with the battery’s electrolyte, performance would be negatively affected. Stanford has published an investigation report.

The Stanford researchers see opportunities to actually put the technology into practice. They do state that the tests until now consisted of manually heating an electrolyte with a membrane. Tests where a battery is bent, broken or punctured have yet to be performed. The tests also have to be carried out on larger batteries.

The fire safety of lithium cells is likely to receive extra attention thanks to the Samsung Galaxy Note 7, which was launched in 2016 and was found to contain an unsafe battery. This tended to spontaneously catch fire and in some cases explode. This happened, for example, in an American airliner. Samsung has recalled all copies of the smartphone. On Monday, January 23, the company will announce the results of the investigation into the case. That date was announced on Monday. Anonymous Samsung sources from Reuters claim that the company will argue that it was not the design or the software of the phone, but the battery.