Part of a battery getting better means getting safer.
Scientists at Penn State’s Battery and Energy Storage Technology (BEST) Center have been working on improvements in li-ion battery safety. They have inserted sensors that would warn users to potential internal problems.
Li-ion batteries are common, as they are light, small, and provide more energy, relative to their size, than other batteries. They are popular for use in portable electronics, like mobile phones, as well as airplanes and vehicles. These batteries are usually safe to use, but when incidents like battery fires on a Boeing Dreamliner and hoverboards make the news, it puts the focus on issues with these batteries.
Inside a li-ion battery is a flammable electrolyte solution that is typically not dangerous. However, thermal runaway, which is when a battery overheats and may subsequently catch on fire, is a possible outcome when the battery is damaged, or overcharged.
These types of units are becoming more energy dense – they are the same size, but expected to have longer lifespans. When more energy capacity is compressed into a smaller space, extra care must be taken for li-ion battery safety.
At the BEST Center, the sensors researchers are using monitor the internal temperature of a battery, as well as detect issues and provide a warning that could allow for early intervention. Called internal reaction temperature sensing (RTS), this has implications for the usage and safety of batteries moving forward.
Battery cells generate heat inside, and it can take a while for the external temperature to rise due to the encasement of the battery. External sensors may recognize an issue too late for anything to be done if the temperature approaches a dangerous level. RTS monitors the temperature and the source of reaction, and can detect changes quickly and accurately.
RTS is one component of a larger objective at Penn State of creating smart batteries. These units would have built-in sensors and actuators to enhance life, performance and safety. As new technology emerges, like drones or robots, li-ion battery safety will have to keep up to avoid hampering progress.
