Why do Farah capacitors activate when they're in series?

Farad capacitors are super-capacitors. The voltage resistance of a single capacitor is very low, generally 2.7V. Used in series to increase the voltage. Generally used in series for uniform charging of each capacitor, each capacitor is provided with an equalization plate. Each capacitor is discharged before recharging, and should be pre-charged (activated) at a low voltage before being used officially to ensure that each capacitor is uniformly charged during subsequent charging.

In addition, due to the manufacturing process of super capacitors(internal carbon fiber and distilled water), the leakage and internal resistance are relatively large before they are activated, and the capacity is not nominal, and they are activated as long as they are charged several times. This is equivalent to using electrolytic capacitors.

The Farad capacitor is a Super capacitor, and the pressure of a single capacitor is very low, usually 2.7 V. The use of series is to increase the voltage. Generally used in series for the uniform charging of each capacitor, each capacitor is equipped with an equilibrium plate. Before recharging, each capacitor is discharged. Before formal use, a low voltage pre-charge(activation) should be used to ensure that each capacitor is evenly charged during subsequent charging.

In addition, due to the manufacturing process of super-capacitors(internal carbon fiber and distilled water), the leakage and internal resistance are relatively large before they are activated, and the capacity is not nominal, and they are activated as long as they are charged several times. This is equivalent to using electrolytic capacitors.

Super-capacitors, also known as electrochemical capacitors, double-layer capacitors, gold capacitors, and Farah capacitors, were developed from the 1970s and 1980s to store energy through polarized electrolytes.

Unlike traditional chemical power sources, it is a power source with special properties between traditional capacitors and batteries. It mainly relies on double layers and Redox enthalpy charge to store electrical energy. However, there is no chemical reaction in its energy storage process. This energy storage process is reversible, and it is also because this super-capacitor can repeatedly charge and discharge hundreds of thousands of times.

The specific details of the structure of the super-capacitor depend on the application and use of the super-capacitor. These materials may vary slightly due to the manufacturer or specific application requirements. The common feature of all super-capacitors is that they contain a positive electrode, a negative electrode, and a diaphragm between these two electrodes. The electrolytic fluid fills the pores of the two electrodes separated by the two electrodes and the diaphragm.

The structure of the super-capacitor is composed of porous electrode materials, collecting fluids, porous battery diaphragm and electrolytes with a high specific surface area. The electrode material and the collector fluid should be closely connected to reduce the contact resistance; The diaphragm shall meet the conditions of as high as possible Ionic conductivity and as low as possible electron conductivity, and is generally an electronic insulating material with a fiber structure, such as a Such as polypropylene film. The type of electrolyte is selected according to the properties of the electrode material.

The components of super-capacitors can vary from product to product. This is determined by the geometry of the Super capacitor packaging. For the placement of Prismatic or square encapsulated product components, the internal structure is based on the setting of the internal components, that is, the internal collector is extruded from the stack of each electrode. These collector solders will be welded to the terminal, thereby extending the current path outside the capacitor.

For round or cylindrical encapsulated products, the electrode is cut into scrolls. Finally, the electrode foil is welded to the terminal to extend the capacitance current path outside.

Its basic principle, like other types of double layer capacitors, is to use a double layer structure composed of activated carbon porous electrodes and electrolytes to obtain an oversized capacity.

The outstanding advantages are high power density, short charging and discharging time, long cycle life, and wide operating temperature range. It is the largest type of double layer capacitor that has been put into mass production in the world.

According to the different mechanisms of energy storage, it can be divided into the following two categories:

1, double layer capacitance: is generated at the electrode / solution interface through the orientation of electrons or ions to cause charge confrontation. For an electrode / solution system, a double layer is formed at the interface of an electronically conductive electrode and an ionically conductive electrolyte solution. When the electric field is applied to the two electrodes, the cathode and cation in the solution migrate to the positive and negative electrodes respectively, forming a double layer on the electrode surface; After the electric field is withdrawn, the positive and negative charges on the electrode are attracted to the opposite charge ions in the solution to stabilize the double layer and produce a relatively stable potential difference between the positive and negative poles. At this time, for an electrode, an isotropic ion charge equivalent to the charge on the electrode will be generated within a certain distance(dispersion layer), so that it will remain electrically neutral; When the two poles are connected to the external circuit, the charge on the electrode migrates and a current is generated in the external circuit. The ions in the solution migrate into the solution and are electrically neutral. This is the charging and discharging principle of the double layer capacitor.

2, Faraday quasi-capacitance: Its theoretical model was first proposed by Conway. It is a two-dimensional or quasi-two-dimensional space on the surface of the electrode and near the surface or body phase. the electrode active material undergo under-potential deposition, resulting in highly reversible chemical desorption. Accompanying with Redox reaction, Generates capacitance associated with electrode charging potential. For Faraday quasi-capacitors, the process of storing charges includes not only storage on the double layer, but also Redox reactions between electrolytic liquid ions and electrode active substances. When ions in the electrolyte(such as H +, OH-, K +, or Li +) diffuse from the solution to the electrode / solution interface under the action of an applied electric field, It enters the body phase of the active oxide on the surface of the electrode through the Redox reaction on the interface, allowing a large amount of charge to be stored in the electrode. When discharging, these ions entering the oxide will be returned to the electrolyte through the reverse reaction of the above Redox reaction, and the stored charge is released through the external circuit. This is the charging and discharge mechanism of Faraday's quasi-capacitance.

(1) The charging speed is fast, and the charging capacity can reach 95 % or more of its rated capacity in 10 to 10 minutes;

(2) Long recycling life, deep charging and discharging cycle use up to 1 to 500,000 times, no "memory effect";

(3) Super current discharge ability, high energy conversion efficiency, small process loss, high current energy cycle efficiency ≥ 90 %;

(4) High power density, up to 300W/KG ~ 5000W/KG, equivalent to 5 to 10 times the battery;

(5) There is no pollution in the composition, production, use, storage and dismantling of raw materials of products, and it is an ideal green and environmentally friendly power source;

(6) The charging and discharging line is simple, and the charging circuit like a rechargeable battery is not required. The safety factor is high and the long-term use is maintainable;

(7) The ultra-low temperature characteristics are good, and the temperature range is -40 °C ~ +70 °C;

(8) Convenient detection, the remaining power can be read directly;

(9) The capacity range is usually 0.1 F-1000F.

advantage

The capacity to reach the Farah level at a very small volume;

No special charge circuit or control discharge circuit is required;

Compared with batteries, overcharge and over-discharge do not have a negative impact on their life span;

From an environmental perspective, it is a green energy source;

Super-capacitors can be welded, so there are no problems such as weak battery contact;

disadvantage

If used improperly, it will cause electrolyte leakage and other phenomena;

Compared with aluminum electrolytic capacitors, it has a large internal resistance and can not be used for AC circuits;

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