An overview on in situ/operando battery sensing methodology through thermal and stress measurements

The regular operation of lithium-ion batteries (LIBs) undergoes diverse electrochemical reactions. How to monitor the state of batteries timely and precisely, such as tracing the charge-discharge process and battery lifespan and conducting fault diagnosis, has aroused countless interests. Complying with the fast, massive, and economic requirements of industries, in situ/operando measurements are promising candidates for real-time monitoring and great support for precise battery state estimation. Numerous micro-/macro-scale techniques have been brought about to reveal the battery behavior in real-time, among which battery sensors have stood out by virtue of their portability, economic friendliness, and precision. Herein, the heat and stress behavior during battery electrochemical reactions are analyzed at first, followed by the elaborate introduction of recent advances in battery sensors, which contains the method, experimental outcomes, and the interpretation of obtained data. Moreover, the Fiber Bragg Grating sensor (FBG) is especially emphasized and carefully reviewed, which has high potential in industrial detection and practical application.