Product Application
Liquid cooling system plays an important role in optimizing the performance of batteries and powertrains in electric vehicles. Because liquid cooling is of high heat capacity and thermal conductivity, it is currently the preferred thermal management solution for many electric vehicles. Accurate temperature monitoring of the fluid in the coolant loop helps the thermal management system maintain the optimal operation of batteries and other components. To address the need for accurate temperature control in electric vehicles, THINKING offers two distinct temperature sensing solutions that enable integration into liquid cooling lines: The Inline Flow-Through Fluid Temperature Sensor for direct hose connection and Plug-In Type Temperature Sensor for assembling with a quick connector. Both temperature sensors are lightweight and compact and provide accurate readings for conditioning the coolant loops' temperature.
Sensor for Direct Hose Connection
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The Inline Flow-Through Fluid Temperature Sensor comprises a hydrolysis-resistant plastic tube and a specialized NTC thermistor engineered for application in harsh environments. The NTC temperature sensor is designed to directly connect with inlet or outlet hoses, measuring the temperature of the fluid flowing through its sensing top. It features excellent measurement accuracy and an integrated connector base that enhances flexibility in replacing a compatible connector.
The temperature sensor offers two configurations for connecting with a rigid polymer or elastomeric hose. The hose barb fitting type grips the inside of a rigid polymer hose and provides a secured connection, as demonstrated in the installation example above. On the other hand, the one for the elastomeric hose is without a barb fitting and requires an additional clamp to increase the holding power for securing the connection.
Quick Connector
The Plug-In Type NTC Temperature Sensor enables fast installation with a compatible quick connector, offering a space-efficient temperature sensing solution for monitoring coolant temperature. Distinguished by its exceptional measurement accuracy, thermal stability, and ability to assemble with a compatible quick connector, the sensor design minimizes spatial impact, streamlines installation, and ensures reliable connections. Two sensor structures accommodate different quick connector types, providing design and installation flexibility.
Accuracy and Thermal Stability
To ensure the sensors meet the customer requirements and work as expected, THINKING conducts a series of comprehensive and application-specific validation tests. One such specification requires the difference in temperature measured by the temperature sensor and the fluid being detected to remain within ±1°C. Our engineering team conducted several measurement accuracy tests and optimized the NTC temperature sensor design to meet the stringent requirement.
The measurement accuracy test aimed to determine if the temperature sensors could precisely measure the coolant temperature in a simulated low-temperature environment and achieve the required accuracy level (±1°C). In this test, the NTC temperature sensors were connected to hoses and exposed to a steady ambient temperature of -30℃. Meanwhile, thermocouples were securely positioned near the temperature sensor's sensing top to contact the fluid directly. Next, a 20℃ fluid was introduced into the hoses. The resulting temperature differences between the readings obtained from the NTC temperature sensors and those from the thermocouples (considered the fluid temperature) were recorded for comparison. The test results below show temperature differences ranging from -0.1° to -0.3°C, indicating that the temperature sensors significantly outperformed the specified requirement, ensuring accurate coolant temperature monitoring within the thermal management system.
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Another challenging requirement for the temperature sensor was maintaining long-term stability under a testing procedure combining thermal shock and immersion testing with applied voltage. The NTC temperature sensors first went through 1000 cycles of thermal shock. After that, the same testaments were loaded with 5V DC and immersed in water at 80°C for 500 hours. The test results show minimal R25 change rates, indicating the sensors maintain excellent long-term thermal stability.
Watch the video to learn more about the temperature sensors:
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Sensor dimensions, terminals, connectors can be customized according to customer-specific requirements. Alternative resistance ratings, resistances tolerances, and R/T characteristics, are available on request.
THINKING has designed NTC temperature sensors with different geometry for specific application requirements. Include temperature sensor design in your product concept phase will allow our sensor design engineers to provide our thermal design experience and optimize the temperature sensor integration.
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