| 초록 |
Current Li-ion battery technology entirely relies on monitoring external physical measurements, voltage, current, and temperature, in order to estimate battery state of health (SOH) and control long-term battery cycles. Due to the poor detection sensitivity and intermixed signals generated from anode and cathode electrodes in external measurements, advanced in-situ monitoring tools are urgently needed to safely and fully utilize Li-ion batteries. Here we achieve in-situ monitoring of battery state by an internally installed optical fiber brag grating (FBG) sensor. Given the sensitivity of FBG sensors on strains, we discover reproducible peak shifting and splitting in the reflected optical spectra according to different states of charge and discharge. The peak shifting and splitting in single-mode FBG sensor are attributed to longitudinal and transverse strains along the entire length of the grating. These discoveries demonstrate the feasibility of an FBG sensor to internally monitor battery behavior, thereby enabling better design of high performance safe batteries.
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