The safety of power batteries in the automotive industry is of paramount importance and cannot be emphasized enough. As lithium-ion battery technology continues to evolve, the energy density of these batteries increases, thereby amplifying the potential risks linked to battery failures. This study explores pivotal safety challenges within the electric vehicle sector, with a particular focus on thermal runaway and gas emissions originating from lithium-ion batteries. We offer a non-dispersive infrared (NDIR) gas sensor designed to efficiently monitor battery emissions. Notably, carbon dioxide (CO₂) gas sensors are emphasized for their ability to enhance early-warning systems, facilitating the timely detection of potential issues and, in turn, improving the overall safety standards of electric vehicles. In this study, we introduce a novel CO₂ gas sensor based on the advanced pyroelectric single-crystal lead niobium magnesium titanate (PMNT), which exhibits exceptionally high pyroelectric properties compared to commercially available materials, such as lithium tantalate single crystals and lead zirconate titanate ceramics. The specific detection rate of PMNT single-crystal pyroelectric infrared detectors is more than four times higher than lithium tantalate single-crystal infrared detectors. The PMNT single-crystal NDIR gas detector is used to monitor thermal runaway in lithium-ion batteries, enabling the rapid and highly accurate detection of gases released by the battery. This research offers an in-depth exploration of real-time monitoring for power battery safety, utilizing the cutting-edge pyroelectric single-crystal gas sensor. Beyond providing valuable insights, the study also presents practical recommendations for mitigating the risks of thermal runaway in lithium-ion batteries, with a particular emphasis on the development of effective warning systems.

An integrated self-powered wireless sensing system combining power management, sensing, modulation, and wireless transmission based on triboelectric-discharge effect is proposed. The system incorporates a triboelectric nanogenerator (TENG), a sensitive module, and a movable breakdown discharger (MBD). The high voltage of the TENG triggers the breakdown discharge at the MBD to emit wireless electromagnetic (EM) wave signals. Theoretical models of the wireless sensing system based on triboelectric-discharge effect are established to analyze the wireless sensing mechanism. Frequency modulation of wireless signals is investigated by connecting different inductances and capacitances via simulations and experiments. The experimental results match well with the theoretical results with a Max. Error of 7.6%. The fabricated wireless humidity sensor as an example realizes the humidity sensing by capacitance variation of humidity-sensitive module affecting the base frequency of the wireless signal, exhibiting a long effective transmission distance (up to 100 cm) and excellent stability. This work provides an innovative design reference for self-powered wireless sensor.

Tire pressure monitoring systems (TPMSs) are essential for maintaining driving safety by continuously monitoring critical tire parameters, such as pressure and temperature, in real time during vehicle operation. Among these parameters, tire pressure is the most significant, necessitating the use of highly precise, cost-effective, and energy-efficient sensing technologies. With the rapid advancements in micro-electro-mechanical system (MEMS) technology, modern automotive sensing and monitoring systems increasingly rely on MEMS sensors due to their compact size, low cost, and low power consumption. This study presents a novel high-precision capacitive pressure sensor based on a capacitive micromachined ultrasonic transducer (CMUT) structure and a silicon–silicon direct bonding process. The proposed design offers exceptional performance with high accuracy, ultra-low power consumption, and reduced production costs, making it an optimal solution for enhancing the precision and efficiency of TPMS. Leveraging its low power requirements, capacitive sensing technology emerges as a superior choice for energy-efficient systems in the automotive industry.

To meet the requirements of parameter testing under special environments, we conduct research on multiparameter integrated sensors. This article proposes a flexible multisensor system based on MEMS beam structures, which utilizes MEMS double-clamped beam and MEMS V-shaped beam to test two parameters of curvature and threshold temperature. Due to the interference between loading temperature and loading curvature during the testing of the multisensor system, a multiphysics coupling model of the system is established to analyze the mutual effect between the two sensors under the loading of temperature and curvature. Multiple sensors have been designed and fabricated on flexible liquid crystal polymers (LCPs) substrate, and the effects of substrate bending and temperature variation on sensor performance testing are characterized. The experimental results of the curvature sensor are consistent with the theoretical predictions within a maximum error of 6.81%. When the ambient temperature is below the threshold temperature, the curvature sensitivity is 5.2 MHz/m $^{-\text{1}}$ and the influence of ambient temperature on curvature testing is negligible. When the ambient temperature reaches the threshold temperature, the curvature sensitivity is 5.4 MHz/m $^{-\text{1}}$ The experimental results of the threshold temperature sensor agree with the theoretical predictions within a maximum error of 9.68% when substrate curvature varies. The resonant frequency offset of the substrate in a flat state is 350 MHz at the threshold temperature.