common lithium-ion battery with a nickel manganese and cobalt cathode has a known chemical composition (Figure 3). The hydrogen concentration is critical; if it approaches 4%, hydrogen’s lower explosive limit, there is a possibility of an explosion or fire. Actions should be taken to prevent the cell from going into thermal runaway. The pressure sensor can detect small increases in pressure inside a battery pack caused by venting. False positives can be avoided by cross-checking any increase in pressure with the other sensor measurements.
This multi-parameter sensor also monitors for too cool of an operating condition. Large battery packs in EVs and BESS often include active cooling to keep the packs from overheating when they are charged or discharged. If they are cooled too much, the internal temperature can drop below the dew point, resulting in condensation inside the pack, potentially shorting the cells and causing thermal runaway. The dew point sensor alerts the BMS before condensation can collect on the battery terminals. Laser AQ sensor Designers of heating, ventilation, and air conditioning (HVAC) systems, air purifiers, and similar applications can use Sensirion’s SPS30 PM sensor to monitor air quality indoors or outdoors. SPS sensors measure mass concentrations of PM1.0, PM2.5, PM4, and PM10, as well as PM0.5, PM1.0, PM2.5, PM4, and PM10 particle counts. It has a mass concentration precision of ±10%, a mass concentration range of 0 to 1000 μg/m3, and an operational life of over ten years. The SPS30 includes an I2C interface for short connections and a UART7 for cables longer than 20 centimeters (cm).
Multi-parameter sensor for battery packs Monitoring air quality is just the start for sensors designed to protect battery packs in EVs and BESS installations. These sensors monitor pressure, air temperature, humidity, dew point, and absolute water content, in addition to volatile organic compounds (VOCs) such as methane (CH4), ethylene (C2H4), hydrogen (H2), carbon monoxide (CO) and carbon dioxide (CO2). During the first phase of battery venting, the gaseous product of a
Figure 3: A specific mixture of gases is characteristic of the first phase of battery venting (Image source: Metis Engineering)
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