Carbon Nanotube-Based Strain Sensor for Excessive Swelling Detection of Lithium-Ion Battery

Along with superior performance of lithium-ion battery, securing its safety has also become increasingly important. The swelling of battery, which can be caused by electrochemical reaction and thermal runaway, could result in significant performance degradation. Thus, it is important to measure the amount of battery swelling in real-time. In this work, a carbon nanotube (CNT)-based strain sensor is used for sensitive measurement of irregular swelling of lithium-ion battery. The CNTs form a percolation network on top of polydimethylsiloxane substrate, and the fabricated sensor is attached on the surface of battery. When the temperature exposure to battery increases, the battery starts to swell, and the sensor is subject to tensile strain. As a result, amount of swelling can be characterized by measuring resistance change of CNTs network. Under our experimental condition, the swelling of battery is ~6 mm at 90°C, and corresponding resistance change of the sensor is ~80%.