The Research On The Failure Mechanism Of Automotive Relays Under The High Temperature Stress

Besides sensors,automotive relays are the most common electronic components on the car . As the car usually works in poor environment, the adverse effects of many factors will probably cause early failure of automotive relays. Therefore the relays are required with high temperature-resistant, cold-resistant, anti-vibration and shock characteristics. In recent years, as people require more and more vehicle comfort ,the traditional 14V electrical system can not meet the high power requirements,and 42V automotive electrical systems gradually emerge. However the automotive electrical system begin to be exposed to a more severe test and the impact of temperature can not be ingored. Therefore, the study about failure mechanism of automotive relays under high temperature is of practical significance.Based on the low-voltage electrical appliances reliability theory, we study the reliability test methods for automotive relays under high temperature ,design the circuitry of the reliability life test device of automotive relay, including data processing circuit and coil drive circuit and control software. Finally, we complete life test of automotive relays in the thermostat humidity box under high temperature stress and analyse the test results and failure mechanism of samples.In this thesis, signal is collected through data singal acquisition card and the program control is achieved by the IPC.Software is completed in VISUAL C++ compile environment, which can be accurate timing, real-time obtaining, processing, displaying the data, and the user interface is simple and clear, user-friendly for observing and operating.