后期维护的便利性
      生产线的稳定、可靠、高效，是直接影响企业效益的，近宁德时代董事长曾毓群在世界动力电池大会上也提到3点要求：“是对研发能力提出更高的要求;第二是大规模交付对制造能力提出更高的要求;第三是产业纵深发展对服务能力提出更高要求。”这其中第二点就是针对制造能力的，现代的工业生产已经不再是单机设备加工了，是需要整个生产过程实现完全的自动化，任何的自动化生产线无论技术先进与否，都要围绕着稳定、可靠、高效的目标去实行。


与防水透气组件对接的螺纹接口处使用密封圈密封，从而保证传感器与外界环境的连通，通过组件可以隔绝水分进入传感器内部，达到透气防水的目的。为了保证防水和防振动的效果，在螺纹处涂抹少量螺纹保护胶。1.4.2 防水透气组件设计

防水透气组件选择金属材料，通过螺纹连接方式安装到传感器的合适位置，同时应考虑工作温度、环境湿度、防水要求和冲击、振动等环境适应性要求。

防水透气组件内部为通孔设计，使得组件与外界环境相通，将聚四氟乙烯膨化材料填充在组件内部，四周压紧，防止水分从聚四氟乙烯膨化材料与组件安装面进入，组件采用螺纹机械接口，可以设计成M3/M4 等直径较小螺纹，为后续组件安装预留足够安装空间，组件如下图所示。2 实验验证

2.1 透气实验

表压传感器是通过感受测试介质和大气压力差值输出差分的信号。若传感器透气性不好，使传感器内外存在明显压差，将导致传感器在不同的海拔高度下测试输出有明显差异。

通过低气压试验箱进行透气性试验，在海平面和海拔7 620m 高度下分别进行传感器性能测试，测试结果及对比结果见表1。结果表明从海平面到海拔7 620m传感器输出信号变化较小。说明在从海平面到高海拔过程中，传感器内部气体的大气压力也随着海拔高度的升高而发生改变，只有当传感器内部气体压力与外界环境气体压力相等时，才能使得传感器的表压输出信号不发生改变。实验证明海拔高度升高过程，传感器内部气体可自由出入传感器，因此可证明材料透气性良好。2.2 防水实验

能否隔绝雨水冲击是该类型传感器的重要指标，因此采用IP67 淋雨试验验证其防水性能。

将表压传感器放入喷淋试验箱The structural design of the sensor is aimed at the requirements of the sealing protection and waterproof of the gauge pressure sensor. Considering all aspects, a vent for installing waterproof and breathable components is designed at the upper end of the sensor shell to realize the ventilation and waterproof functions of the entire sensor. Figure 3 shows the ventilation structure of the sensor.



The threaded interface connected with the waterproof and breathable component is sealed with a sealing ring to ensure the connection between the sensor and the external environment. The component can prevent moisture from entering the sensor, so as to achieve the purpose of breathable and waterproof. In order to ensure the effect of waterproof and anti-vibration, apply a small amount of thread protection glue at the thread. 1.4.2 Waterproof and breathable component design



The waterproof and breathable components shall be made of metal materials and installed at the appropriate position of the sensor through threaded connection. At the same time, the working temperature, ambient humidity, waterproof requirements, impact, vibration and other environmental adaptability requirements shall be considered.



The interior of the waterproof and breathable module is designed with a through-hole to make the module communicate with the external environment. The polytetrafluoroethylene expanded material is filled in the module and pressed around to prevent water from entering from the polytetrafluoroethylene expanded material and the mounting surface of the module. The module uses a threaded mechanical interface, which can be designed into M3/M4 threads with smaller diameter, so as to reserve enough installation space for the subsequent installation of the module, as shown in the following figure. 2 Experimental verification



2.1 Air permeability test



The gauge pressure sensor outputs a differential signal by sensing the difference between the test medium and atmospheric pressure. If the air permeability of the sensor is not good, there is a significant pressure difference between the inside and outside of the sensor, which will lead to a significant difference in the test output of the sensor at different altitudes.



The permeability test is carried out through the low pressure test chamber, and the sensor performance test is carried out at sea level and altitude of 7620 m. The test results and comparison results are shown in Table 1. The results show that the output signal of the sensor changes little from sea level to 7620m above sea level. It shows that during the process from sea level to high altitude, the atmospheric pressure of the gas inside the sensor also changes with the elevation. Only when the pressure of the gas inside the sensor is equal to the pressure of the external environment gas, can the gauge pressure output signal of the sensor not change. The experiment proves that the gas inside the sensor can enter and exit the sensor freely when the altitude rises, so it can prove that the material has good permeability. 2.2 Waterproof test



It is an important indicator of this type of sensor whether it can insulate rain impact, so IP67 rain test is used to verify its waterproof performance.



Put the gauge pressure sensor into the spray test chamber