Aluminum electrolytic capacitor failure mechanism, failure mode Capacitance knowledge

by:Thermistor-Mov     2020-06-23
Aluminum electrolytic capacitor failure mechanism, failure mode, aluminum electrolytic capacitor failure mechanism is mainly introduced in this paper, the application environment, this article about 970 words, read the full article 10 minutes. An overview, aluminum electrolytic capacitor failure mode and the factors of aluminum electrolytic capacitor anode, cathode lead electrode and the shell is high purity aluminum, aluminum electrolytic capacitor of the medium is the 3 oxidation 2 aluminium film formed on the surface of the anode, the real is the cathode electrolyte, work is quite an electrolytic cell, anodic oxidation layer is formed on the surface of the anode, just no longer produce electrochemical reaction, the theoretical current is zero, because of the existence of the electrode and the electrolyte impurities can cause small leakage current. Look from the phenomenon, the aluminum electrolytic capacitor common failure modes and failure phenomenon are as follows: the electrolyte dry, pressure release device, short circuit, open circuit ( Without electricity capacity) The high, leakage, etc. Aluminum electrolytic capacitor applications if there is no problem on the quality of aluminum electrolytic capacitors, the occurrence of failure problem is appeared in the application environment. Aluminum electrolytic capacitor design applications mainly include: the environment temperature, cooling pattern, such as voltage, current parameters. For capacitor, users, short circuit, open circuit to make it lose the function of the capacitor. Several other kinds of failure modes, That is caused by the second factor of failure) , generally classified as & other; The deteriorating & throughout; , or & other; Run out of the failure & throughout; 。 Second, the failure mechanism of the aluminum electrolytic capacitor, exhausted failure usually judge the end of the service life of electrolytic capacitor was based on down to the rated capacitance ( The initial value) Less than 80%. Due to the early aluminum electrolytic capacitor electrolyte filling, electric capacity of aluminum electrolytic capacitor slow decline in the early work. With the repair working electrolyte during load times of impurity damage caused by anodic oxidation film electrolyte gradually reduced. To use later, due to the electrolyte, less volatile increase viscosity of the electrolyte is difficult to fully contact with the corrosion process of crude oxide film on aluminum foil surface layer, thus make the aluminum electrolytic capacitor plate effective area decreases, and the anode, cathode foil capacity decreases, causing a sharp drop in capacitance. Therefore, can be thought of aluminum electrolytic capacitor has a capacity of decrease is caused by the electrolyte volatilization. Due to the volatilization of the electrolyte of the main reason is the high temperature environment or fever. 2, run out of failure due to the application conditions make aluminum electrolytic capacitor fever aluminum electrolytic capacitor in the work is the cause of the rectifier filter ( Including the output of high frequency switch power supply rectifier filter) And power when the power of the electric furnace bypass ripple ( Or pulse) Current flows through the aluminum electrolytic capacitor, the loss is converted into heat generated in the aluminum electrolytic capacitor ESR make it hot. When aluminum electrolytic capacitor has thickened more electrolyte evaporation and solution, resistivity due to viscosity increasing rise, make the equivalent series resistance of working electrolyte increases, lead to loss of capacitor rise obviously, loss Angle increases. Such as the electrolytic capacitor for the working temperature of 105 degrees, the core temperature higher than 125 degrees, the electrolyte increased viscosity, the electrolyte of the ESR increased nearly 10 times. 。 The equivalent series resistance of the increase will produce a larger quantity of heat, cause greater volatility of the electrolyte. Cycling, aluminum electrolytic capacitor capacity fell sharply, fail, at risk. 3, run out of failure often leads to aluminum electrolytic capacitor leakage current is added. Application of high voltage and high temperature can cause the increase of leakage current. Link address: this paper label: aluminum electrolytic capacitor a: the next test method of aluminum electrolytic capacitor, electrolytic capacitor selection of main parameters
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