INTERNAL STATE DETECTING SYSTEM AND METHOD FOR ENERGY STORAGE DEVICES

An in-situ and in-operando internal state detecting system for an energy storage device comprises a first acoustic signal-emitting acoustic signal emission module, an interior-residing optical sensing module, and a first input optical signal-providing signal demodulation module. The optical sensing module receives a second acoustic signal when the first acoustic signal transmits inside the energy storage device, and outputs a first optical signal, which is demodulated and analyzed by the signal demodulation module to obtain acoustic feature information. Optionally, the signal demodulation module also provides a second input optical signal, and the optical sensing module outputs a second optical signal, which is analyzed by the signal demodulation modulation module to obtain optical feature information. Based on the acoustic and optical feature information, one or more internal states of the energy storage device, such as dendrite growth, internal gas generation, electrode expansion, electrolyte aging, or refractive index, etc., can be determined.