Aluminum electrolytic capacitor manufacturing process

Aluminum Electrolytic Capacitor Manufacturing Process

During the aluminum electrolytic capacitor manufacturing process, it is important that the capacitor is conditioned to maximize its performance and service life. This is accomplished by mounting the aluminum capacitor in an aluminum case, applying impregnation, and reimpregnating with a second conductive electrolyte.

Impregnation

During the aluminum electrolytic capacitor manufacturing process with Low ESR Solid Aluminum Electrolytic Capacitor, the anode and cathode foils should be protected from direct contact with each other. If the anode and cathode are not separated, the component can develop an internal short circuit. This can be a problem if the capacitor is used at low voltage.

The anode and cathode foils are then placed in an electrolytic bath, where the aluminum is oxidized. An electrically insulating layer of Al2O3 is formed on the surface of the aluminum. The thickness of the oxide layer is directly proportional to the applied voltage.

The anode and cathode are then rolled into cylindrical sections. Special chemical treatments are then applied to the anode and cathode to form a film that will be smoother and provide more protection. The aluminum is then anodic oxidized.

The anode and cathode can then be separated by means of a separator, which is made of high purity paper. This physically separates the metal foils, extending the lifetime of the capacitor.

Source:https://i.pinimg.com

Mounting in an aluminum case

Typically, aluminum electrolytic capacitors are used in switched-mode power supplies, DC-DC converters, and frequency converters. They have relatively high capacitance values and good decoupling properties at lower frequencies. However, they can be damaged by frequent charge and discharge cycles. In addition, they have a short lifetime when used in DC applications.

These types of electrolytics are not recommended for use in AC applications. In order to improve their life, they should be force-cooled. This is achieved by placing a insulating shrink sleeve around them. They also need to be mounted carefully. If the sleeve is not soldered properly, it can cause the capacitor element to be damaged.

The standard aluminum electrolytic capacitor is not designed for circuits and SMD Standard Aluminum Electrolytic Capacitor with frequent charge and discharge cycles. This can result in the capacitor’s capacitance value dropping. To prevent this, it is recommended that the sleeve be soldered only to the capacitor’s terminals. If it is soldered to the traces of the circuit board, it may melt and damage the sleeve.

Source:https://i.pinimg.com

Reimpregnating with a second conductive electrolyte

During the past, electrolytic capacitors were considered to be unreliable components. They are typically based on chemically reactive materials that can affect the mechanical integrity of the capacitor and its long-term performance. The public image of aluminum electrolytic capacitors with non-solid electrolytes has been negative.

The problem with the previous systems is that they were often contaminated during manual manufacturing. This caused high leakage currents. Modern electrolytic capacitors have a safety vent built into the case. The vent is designed to vent hot gas if the capacitor fails. The vent can be scored so that the outside circuit is not exposed.

One of the main shortcomings of aluminum electrolytic capacitors with non-solid electrodes is the volatility of the liquid electrolyte solutions. This instability of the oxide in the liquid electrolyte solution can result in the degradation of charging efficiency. In addition, the loss of the electrolyte solution can occur through leaks in safety vent structures. The solution can also be lost through diffusion through a rubber sealing plug.

Service life

During the manufacturing process, aluminum electrolytic capacitors undergo several changes. These changes are caused by chemical reactions between the aluminum oxide film and the electrolyte with Snap-in Type Standard Aluminum Capacitor 85℃.

Aluminum electrolytic capacitors are used in various applications, including industrial power supplies, DC-DC converters, and frequency converters. The service life of these devices depends on a number of factors.

The major factors influencing the service life of aluminum electrolytic capacitors include ripple current, internal temperature, and ESR. The rated ripple current is a reflection of the maximum value that the capacitor can endure for a specified lifetime. The rated value is usually calculated by the manufacturers. Using these values, the sensitivity of the capacitor can be determined.

The ripple current varies based on the frequency and amplitude of the incoming AC voltage. This ripple current flows through the capacitor as a charge and discharge current. It also causes heat to be generated inside the capacitor core. Typically, the manufacturers take into account this factor in the safety margin calculation.