Application of NTC temperature sensor in new energy vehicle battery pack
October 10, 2021
NTC temperature sensors are more and more widely used in new energy vehicle battery packs. Generally, thermistors with a resistance value of R25=10K and a B value of 3435 or R25=100K and a B value of 3950 are used because the NTC has a fast response speed and small time lag. , The measurement range is -50 degrees -150 degrees, and the measurement accuracy is 1 degree. Only A/D acquisition is required. Generally speaking, multiple temperature probes are required to detect the true temperature of the battery pack force. The sensors used in the battery pack of new energy vehicles mainly include sensors for detecting battery temperature, temperature sensors for monitoring motors, and thermistor temperature sensors for battery cooling systems.
A basic component of the new electric vehicle/hybrid// is an electric motor (commonly known as a motor). In order to ensure the long life of the motor and its best performance, the temperature of the electric motor also needs to be continuously monitored, and work as accurately as possible within the temperature range above 150℃. Therefore, it is also important to determine the temperature of the stator winding. Yes, this is the only way that the motor can take full advantage of its advantages without the risk of overheating. In order to measure the temperature of the stator, it is also required that the sensor should be easy to install, and to ensure that the sensor is protected from mechanical pressure during installation and operation and has a high dielectric strength. The latter can prevent generation from the driver current circuit to the measurement current circuit. Flashover phenomenon.
The NTC thermistor chip is used as the core component, and it is packaged with a wire nose aluminum ring that is easy to fix (as shown in the figure). NTC thermistor is used in electric motors, which can convert temperature variables into required electronics in the circuit. The central role of signals.
The NTC temperature sensor continues to be in a high temperature environment in an electric motor, and requires fast response characteristics, which puts forward new requirements for NTC thermistors: high reliability (superior thermal shock performance), small thermal time constant (fast response speed) .
The metal shell made of aluminum wire nose can protect the NTC chip well on the one hand. On the other hand, aluminum material has a fast temperature sensing speed. Does not affect the thermal reaction speed of NTC.
The design of the front end of the aluminum shell with a diameter of 4mm can ensure that the NTC has a fast thermal response and is easy to install
Using radial glass seal as the core temperature sensing element, on the one hand, it can ensure that it can work in a high temperature environment. (Working above 150 degrees for a long time), on the other hand, the radial glass-sealed NTC thermistor sinters the glass into a spherical structure, which tightly wraps the NTC thermistor chip. Its reliability is much higher than that of the axial glass seal package structure. In the third aspect, the spherical radial glass-sealed NTC thermistor is more resistant to mechanical stress than the axial glass-sealed NTC thermistor. In the fourth aspect, the radial glass-sealed NTC thermistor has a smaller size (the radial glass-sealed NTC thermistor temperature sensing head size is only 1.3mm. The axial glass-sealed NTC thermistor temperature sensing head size is 6mm. So even though this structure is covered with an external copper shell, its response speed is not affected too much.
There is a heat-shrinkable sleeve all-inclusive design between the hardware head of the NTC temperature sensor wire nose and the wire, which can withstand greater cold and heat shocks and prevent the shell from falling off.
The NTC temperature sensor wire of the new energy battery pack adopts a 150-degree temperature-resistant double-pin fluorine wire, and a black heat-shrinkable tube is added to better protect the wire and enhance the strength of the wire.
Professional NTC thermistor manufacturer AMPFORT can provide free samples of temperature sensors in battery packs of new energy vehicles, please call us for details!