In a significant advancement for autonomous driving and new energy vehicles, scientists have proposed a multifunctional frequency modulated continuous wave (FMCW) LiDAR system that can perform high-precision 3D imaging and multi-parameter sensing simultaneously. This innovative technology, detailed in a paper published in Light: Science & Applications (DOI: 10.37188/lam.2026.102), addresses the critical need for integrated systems that can monitor both the external environment and the internal state of a vehicle's battery, potentially preventing thermal runaway incidents.
The research, led by Professor Yongkang Dong from the National Key Laboratory of Laser Spatial Information at Harbin Institute of Technology, China, and co-workers, introduces a system that detects echo signals from both free space and optical fiber. This dual detection allows the LiDAR to provide 3D imaging of objects in the surroundings while simultaneously measuring environmental parameters such as temperature, gas concentrations, and liquid density. In proof-of-concept experiments, the team achieved 3D imaging of a target at 30 meters with adjustable resolution between 0.3 cm and 1.2 cm. Concurrently, they measured the electrolyte density and temperature of a battery with accuracies of 3×10⁻⁵ g/mL and 0.5 °C, respectively. Additionally, the system detected concentrations of gases critical for monitoring thermal runaway—C2H2, CO2, and CH4—with detection limits of 0.07 ppm, 48 ppm, and 0.56 ppm, respectively.
Traditional FMCW LiDAR systems are limited to 3D imaging and cannot detect internal battery states or environmental parameters. In electric vehicles, thermal runaway poses a significant safety risk, and early warning requires coordinated monitoring of multiple parameters such as temperature, electrolyte density, and characteristic gases. Currently, these functions are performed by separate imaging and sensing systems, leading to high complexity, elevated costs, and integration challenges. The proposed multifunctional LiDAR overcomes these limitations by merging both capabilities into a single demodulator, offering a more compact and cost-effective solution.
The operational principle extends FMCW LiDAR technology into optical fibers, realizing an optical frequency domain reflectometry (OFDR) system. OFDR uses a linearly modulated continuous light source for fiber measurement, sharing the same positioning principle as FMCW. It offers high spatial resolution and large dynamic range, making it suitable for sensing strain, temperature, pressure, and gas concentration. By combining free-space imaging with OFDR-based sensing, the system can simultaneously monitor the external environment and the battery's condition.
The scientists explained that in the LiDAR module, the distance to a target is calculated from the optical path difference between the collimator reflection peak and the target reflection peak. Reflection spectra from fiber Bragg gratings, Fabry-Perot cavities, and multi-pass cells are demodulated from their respective reflection peaks in the spatial domain using inverse Fourier transform. This enables the measurement of temperature, gas concentrations, and liquid density with high precision.
The team envisions widespread application potential in new energy vehicles, where this technology could provide an integrated solution to enhance safety. By simultaneously performing key functions of autonomous driving and battery management, the multifunctional LiDAR could become a cornerstone in next-generation vehicle perception systems. The research was supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, and other funding bodies, underscoring its significance in advancing optical sensing technologies.
