A four-layer stacked winding type self-healing capacitor element

Abstract

The invention provides a four-layer stacking and winding type self-healing capacitor element which comprises a shell. A cylinder formed by winding four layers of metallized films around a hollow tube is sealed in the shell. The two ends of the cylinder are connected with a first lead plate and a second lead plate respectively to be used as capacitor element electrodes. Two layers of metallized films are low-sheet-resistance metallized films with thicker metal layers, and the other two layers of metallized films are high-sheet-resistance metallized films with thinner metal layers. The low-sheet-resistance metallized films and the high-sheet-resistance metallized films are arranged in a spaced mode and stacked and wound to form the cylinder, wherein the low-sheet-resistance metallized films mainly enable capacitance current to flow, so that the loss tangent value is small. The high-sheet-resistance films are used for ensuring the self-healing characteristic, so that the whole capacitor element has the small loss tangent value, meanwhile, the good self-healing characteristic is achieved, self-healing failures are greatly reduced or eliminated, the service life of the capacitor is prolonged, running safety of the capacitor is improved, and reliability of a device where the four-layer stacking and winding type self-healing capacitor element is located is improved.

Description

Technical field [0001] The invention relates to the field of manufacturing self-healing power capacitors, in particular to a four-layered winding type self-healing capacitor element. Background technique [0002] Generally, the manufacture of self-healing capacitors is a cylinder formed by winding two layers of metalized films, with metal particles attached to both ends to form polar plates, and electrodes are drawn through metal leads. If a capacitor fails, it is desired to isolate the capacitor from the power grid or the operating system. The internal failure of the self-healing capacitor is generally a self-healing failure. Self-healing means that when the insulating film breaks down, a short-circuit current is generated between the metal layers. The heat generated by this large current will evaporate the metal coating around the breakdown point, thereby isolating the original short-circuit fault point and recovering the insulation performance. Self-healing failure means that...

AI Technical Summary

Problems solved by technology

Self-healing failure means that if a local single self-healing occurs, the material in this area is damaged and leads to continuous self-healing, breakdown and recovery alternately occur and the fault expands, and finally the capacitor can no longer restore insulation

The thickness of the metal layer during self-healing (generally represented by square resistance) is related to whether the self-healing property is good or not, and the tangent value of the capacitance loss angle: ①The thickness of the metal layer (small square resistance value), the self-healing property is not good Good, but the loss tangent value is small; ②The metal layer is thin (large square resistance), and the self-healing characteristics are good, but the loss tangent value is large, and the thickness of the metal layer, the self-healing characteristics and the capacitor loss tangent value are formed between the three Therefore, there is an urgent need for a capacitor element with a small loss tangent and good self-healing characteristics.

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