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Home > BLOG > Measures to improve the service life of aluminum electrolytic capacitors

Measures to improve the service life of aluminum electrolytic capacitors

January 03,2023

1、 Lower the ambient temperature lower the ambient temperature

So that the capacitor does not work under the upper-limit class temperature, in addition to taking into account the capacitor itself heating effect, this is particularly important for liquid electrolyte type products. If the high temperature, leakage current will increase sharply, gas increase, so that the shell in a state of rapid increase in internal pressure;. Therefore, for the products with long life requirement, the working temperature should be controlled below 50 ° C, so the corresponding life can be increased by 1 ~ 2 orders of magnitude. For example, a computer capacitor that can work for 20 years at 45 ° C can only work for 1-2 years at 85 ° C. The core temperature of the capacitor shall not exceed 95 ° C if it is required to be applied to the upper limit class temperature (85 ° C) , depending on the nature of the working electrolyte chosen. This high temperature effect on solid tantalum capacitors is not as serious as  aluminum electrolytic capacitors , but it is certainly harmful.

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2、 Lower the upper limit of the rated voltage lower the upper limit of the rated voltage

That is, lower the working field strength of the dielectric oxide film, will be applicable to aluminum capacitors. After reducing the load by half, the life of the capacitor can be increased by 2 orders of magnitude. In fact, if the aluminum oxide film is damaged or corroded, the repair of the oxide film can only be carried out under the highest working voltage, and it is difficult to recover the thickness of the oxide film under the original forming voltage locally, therefore, it is not the most suitable measure to reduce the working voltage of  aluminum electrolytic capacitor.

3、 Control the ripple current in operation

When electrolytic capacitors are used in pulsating circuits, the main factor causing power consumption and heating up is the ripple current (or ripple voltage for capacitors of smaller capacity) , in general, the failure rate and temperature curves are measured under the DC voltage without ripple, only considering the leakage current, and the core temperature is almost the same as the ambient temperature. However, in practical applications, due to the ripple current caused by the heating can make the core center temperature rise, the highest can reach tens of degrees Celsius. The temperature rise of the core depends on the ambient temperature of the capacitor and the control of the ripple current. Therefore, the high ripple current easy to cause the core electrolyte dry, capacitor early failure. At the same time, the ripple current for a long time exceeds the specified value, which is also one of the factors leading to the opening of the explosion-proof valve of the capacitor.

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4、 Avoid frequent surge voltage applied to the capacitor

When a circuit is switched on or off, it produces a transient voltage, which is generally greater than the working voltage, and generates a corresponding impulse current if the resistance of both the power supply and the load is small, in this way, the instantaneous current value is quite large, and it is easy to cause damage to the oxide film of the electrolytic capacitor, because the capacitor is easy to heat up in the weak area of the film under the high impact current, which leads to the early crystallization and reduces the voltage resistance, so in order to improve the service life, should avoid the occurrence of frequent surge voltage applied to the capacitor, when the working voltage close to the rated voltage, even more so.

5、 Select capacitors with a low leakage current source

As a long-life use of electrolytic capacitors, in addition to the above 4 additional factors to consider, in the selection also choose the same type of leakage current is particularly small capacitors. This shows that it has high quality oxide film and suitable working electrolyte. Once the ambient temperature is high, the corresponding leakage current increases more slowly. Otherwise, when the leakage current increases sharply, the internal temperature will rise, which in turn will cause the leakage current to increase again until the loss of heat balance and destruction.


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