Technical difficulties of battery thermal runaway monitoring system

        First，Sensor accuracy and reliability

        1. Gas sensor accuracy challenge

        The environment inside the battery pack is more complex, and the gas composition is diverse and the concentration varies widely. For example, hydrogen gas, which is normally extremely low in concentration, may rise rapidly in the initial phase of thermal runaway. To accurately detect small changes in the concentration of these gases, the accuracy of the sensor is extremely high. The current thermal runaway monitoring sensors are susceptible to the interference of environmental factors such as temperature and humidity, resulting in measurement errors.

        Taking electrochemical gas sensors as an example, the detection principle is based on chemical reactions, and other chemicals in the environment may react with the electrodes in the sensor, affecting the detection accuracy of target gases such as hydrogen and carbon monoxide. In practical applications, conditions such as electrolyte leakage inside the battery pack may interfere with the normal operation of the sensor, making it impossible to accurately sense the true change in gas concentration.

        2. The sensor has long-term reliability problems

        The operating environment of commercial vehicles is complex and changeable, including different road conditions, climate conditions and so on. The sensor needs to maintain reliable performance under harsh conditions such as long-term vibration and alternating high and low temperatures. Long-term vibration may cause the components inside the sensor to loosen or damage, affecting its measurement accuracy and stability.

        For example, in the cold winter, the sensor may be slow to respond; In the hot summer, high temperatures may accelerate the aging of sensor materials. Moreover, with the passage of time, the phenomenon of zero drift of the sensor will gradually appear, that is, the output signal of the sensor will also change when there is no target gas, which requires frequent calibration to ensure its reliability, but in the actual operation scenario of commercial vehicles, frequent calibration is difficult to achieve.

        Second，Complexity of data processing and analysis

        1. Complex data interference factors

        During the normal operation of the battery pack, the gas parameters are affected by many factors. For example, the process of charging and discharging causes the chemical reactions inside the battery to produce normal gas releases, and the changes in the concentration of these gases and the changes in the initial phase of thermal runaway can confuse each other. Moreover, changes in operating conditions such as turbulence, acceleration and deceleration during vehicle driving will also have an impact on gas distribution and pressure, making data analysis complicated.

        In addition, different battery types (such as lithium iron phosphate, ternary lithium batteries, etc.) have different gas generation mechanisms and parameter changes during normal operation and thermal runaway. For monitoring systems, it is necessary to be able to distinguish between these normal changes and abnormal changes to accurately determine whether thermal runaway occurs.

        2. Balance of real-time and accuracy

        In order to be able to warn of thermal runaway in time, the data processing system needs to analyze a large number of sensor data in a short time. However, too much pursuit of real-time may lead to a decline in the accuracy of data analysis. For example, using a simple threshold judgment method may generate false alarms due to momentary fluctuations in data.

        At the same time, to improve the accuracy, you need more complex data analysis algorithms, such as machine learning algorithms, but these algorithms have a large amount of computation, which may affect the real-time response speed of the system. In scenarios such as high-speed driving of commercial vehicles, the system must make accurate judgments in a few seconds or even less, which is a huge challenge to the performance of the data processing system.

        Third, system compatibility and integration

        1. Compatibility with different battery packs is difficult

        There are many types and specifications of battery packs for commercial vehicles on the market, and different battery packs have different designs such as structure, size, and gas emission channels. Thermal runaway monitoring systems need to be able to adapt to various types of battery packs, ensuring that the sensor can be accurately installed in the right position to obtain the most efficient gas parameters.

        For example, the gas outlet of some battery packs is in a special position, and the sensor installation of the monitoring system needs to consider how to effectively collect gas samples without affecting the normal function of the battery pack. Moreover, the internal gas flow characteristics of different battery packs are also different, which affects the sensor's perception of changes in gas concentration, and requires special system design and optimization for different battery packs.

        2. Integration challenges with other vehicle systems

        The battery thermal runaway monitoring system needs to be integrated with other systems of commercial vehicles, such as vehicle control systems, instrument display systems, alarm systems, etc. In the integration process, there may be signal interference, communication protocol incompatibility and other problems.

        For example, the vehicle control system may generate electromagnetic interference that affects the data transmission of the monitoring system. Moreover, the communication protocols of different vehicle manufacturers are different, and the monitoring system needs to be compatible with a variety of protocols in order to accurately transmit the early warning information to the vehicle's instrument display system and alarm system, so that the driver can receive the alarm and take measures in time.