Investigation of gas sensing in large lithium-ion battery systems for early fault detection and safety improvement

Large lithium-ion battery systems rely on battery monitoring and management systems to ensure safe and efficient operation. Typically the battery current, the cell voltages, and the cell temperatures are monitored. This paper describes the use of gas sensors in large lithium-ion battery systems in addition to conventionally used means of battery monitoring. An undetected electrolyte leak in a cell can pose a serious threat to users and maintenance personnel. Experiments described in this paper show that a gas sensor can easily detect volatile organic compounds (VOC) from the leaking electrolyte, whereas standard cell monitoring methods can only detect a leak indirectly over premature cell performance degradation. Therefore, gas sensors offer a fast, simple, and cost efficient way to increase the safety of battery systems. This paper gives a description of a suitable gas sensor and its application in a battery system, followed by the identification of relevant use cases. In the experimental section the performance of the gas sensor in these use cases is investigated and evaluated. The paper ends with a summary of the results and a short outlook.