In the process of manufacturing film capacitors, there are many factors affecting the performance of the product. Often, the control of the manufacturing process and the choice of process methods will play a decisive role in the change of the electrical properties of the capacitor. Therefore, when designing the capacitor, we are correctly selecting The dielectric field strength, internal and external structure of the product, main structural materials, capacitor heating and other factors must also consider the reliability design of the manufacturing process, to minimize the occurrence of a large number of self-healing points and the occurrence of a large number of low-resistance short circuits. Therefore, the following points must be noted:
1. Correct selection of dielectric material and dielectric field strength. For polyester film, it is commonly used for DC capacitors. For polypropylene film, it is generally used for AC and low loss DC capacitors.
2. In order to prevent the entry of dust, impurities, etc., which occur in a large amount of self-healing, the evaporation environment and evaporation process of the metallized film should be strictly controlled, and the metallized film and the cut strip film should be properly preserved.
3. In order to avoid a large amount of release when self-healing, the metallized film is simultaneously energized during cutting to reduce the occurrence of electrical breakdown, continuous self-healing and self-healing caused by thermal breakdown during film capacitor manufacturing. Probability.
4. Proper selection of sophisticated voltage and sophisticated methods, that is, the purpose of removing defects and holes without large-scale self-healing points, and at the same time can achieve the purpose of improving reliability.
5. Correctly select the shape of the wound product and the heat treatment temperature and time, in order to achieve the purpose of complete setting, and for the flat wound type product, adopt a thin and wide structure, so that the interlayer pressure of the inner core is large and uniform. , to reduce the probability of occurrence of low resistance short circuit.
6. For film capacitors, the production cycle should be strictly controlled, especially the production cycle before and after heat treatment to prevent zinc oxidation and affect the electrical properties of the film capacitor.
7. Adopt the following reliability process in the manufacturing process: 1 The product is energized to eliminate the self-healing point in the product, avoid the continuity of the product, and improve the insulation resistance and reliability of the product. 2 The product is subjected to temperature shock to remove the product with excessive contact loss, which causes early failure, improves product reliability, screens the voltage and temperature of the finished product, eliminates early failure products, and improves the reliability of the film capacitor product.
Self-healing is an important factor affecting the control and performance of film capacitor production process. Correctly mastering and applying self-healing can control the production process and improve the reliability of capacitors. On the contrary, it will result in the decline of product performance, increased waste and reduced reliability. Therefore, correctly grasping the factors that produce self-healing and affecting self-healing, and reasonable control of applied pressure, applied voltage, and correct selection of metallized film square resistance, etc., will help improve the reliability of film capacitors, reduce scrap rate, reduce costs, and improve Product competitiveness.
