1. Heating rate test method
Testing the heating rate of the ptc heater requires accurate measuring instruments and a reasonable test environment. First, place the ptc heater in a well-insulated test box, and arrange high-precision temperature sensors, such as thermocouples or thermistor sensors, on the surface of the heater and key positions around it to accurately monitor temperature changes. Connect the data acquisition system to record the temperature change data over time. After turning on the heater, collect temperature data at a certain time interval (for example, 10 seconds). The heating rate is determined by drawing a temperature-time curve and calculating the slope of the curve. For example, in the initial stage, if the temperature rises from 20℃ to 80℃ within 10 minutes, the heating rate is (80-20)℃÷10 minutes=6℃/minute. At the same time, the test should be repeated many times to ensure the accuracy and reliability of the data and eliminate the influence of accidental errors.
2. Factors affecting the heating rate
The heating rate of the ptc heater is restricted by many factors. The characteristics of the PTC material itself are the key. Its resistance-temperature coefficient determines the power output at different temperatures, and the thermal conductivity of the material also affects the heat transfer rate. For example, PTC materials with high thermal conductivity can conduct the generated heat faster, thereby accelerating the temperature rise. The contact quality between the electrode and the PTC element is also very important. A large contact resistance will consume some electrical energy, reduce heating efficiency, and affect the temperature rise rate. In addition, the ambient temperature and heat dissipation conditions have a significant impact on the temperature rise rate. In a low temperature environment with good heat dissipation, the temperature difference between the PTC heater and the environment is large, the heat is lost quickly, and the temperature rise rate will slow down; while in a relatively closed environment with slow heat dissipation, the temperature rise rate will accelerate.
3. Ways to achieve rapid temperature rise-material and structure optimization
From the perspective of materials, the selection of PTC materials with high thermal conductivity, such as composite materials with specific thermal conductive fillers, can enhance heat conduction. Optimize the microstructure of the PTC element to make its internal grain distribution more uniform and reduce thermal resistance. In terms of structure, design a reasonable electrode structure, increase the contact area between the electrode and the PTC element, and reduce the contact resistance, such as using a multilayer electrode structure or a special electrode bonding process. At the same time, optimize the overall structure of the heater, reduce the heat accumulation and dissipation path inside, such as using a compact packaging structure, closely combining the heating core and the heat dissipation components, and improving the heat transfer efficiency, so as to achieve rapid heating.
4. Ways to achieve rapid heating-external assistance and control strategy
The heating speed can also be improved with the help of external assistance. For example, at the beginning of the heater startup, a preheating device is used to quickly preheat the PTC element so that it quickly reaches the operating temperature range, and then the PTC heater itself maintains the temperature. In terms of control strategy, an intelligent temperature control system is used to dynamically adjust the input power according to the difference between the set target temperature and the actual temperature. At startup, a higher initial power is given to make the heater heat up quickly. When approaching the target temperature, the power is gradually reduced, which can not only achieve rapid heating, but also ensure accurate temperature control, avoid temperature overshoot, and improve the overall performance and use effect of the PTC heater.
