Built in sensors make lithium-ion batteries safer
Researchers in Penn State’s Battery and Energy Storage Technology (BEST) Center are working to make the lithium-ion (Li-ion) batteries we use every day safer by inserting sensors to warn users of potential problems inside the battery.
Li-ion batteries are extremely common because they are small, lightweight, and provide more energy based on their size than traditional batteries. Li-ion batteries are ideal power sources for mobile electronics, such as laptops, cellphones, and iPods, as well as airplanes and electric and hybrid vehicles.
“Li-ion batteries essentially provide portable power for everything,” said Chao-Yang Wang, William E. Diefenderfer Chair of Mechanical Engineering and professor of mechanical engineering, chemical engineering, and materials engineering.
While in general these batteries are very safe, recent events including battery fires aboard the Boeing Dreamliner and in the currently popular hoverboards underscore significant issues.
Li-ion batteries contain a flammable electrolyte solution that under normal usage is not dangerous. However, if the battery is punctured, as may happen in a car accident, or overcharged due to a malfunction, a problem called thermal runaway can occur. When this happens, the battery may overheat and the battery pack catch on fire.
As devices get smaller and the demand for energy increases, safety becomes a greater concern.
“Your cell phone charge can now last for a week instead of a day, but it’s still the same size. The battery has a lot more energy density, you are compressing more and more energy into a smaller space, and you have to be careful when you do that,” said Wang. “Our job is to come up with solutions to provide safety while at the same time increasing performance.”
Penn State researchers are delivering greater safety by placing temperature sensors inside Li-ion batteries to monitor internal temperatures, detect problems, and provide early warning for intervention. This technology is called internal reaction temperature sensing (RTS).