High-frequency rapid charging and discharging aluminum electrolytic capacitor for servo motor and manufacturing method

Abstract

The invention relates to the technical field of electrolytic capacitors, in particular to a high-frequency rapid charge and discharge aluminum electrolytic capacitor for a servo motor and a manufacturing method, the high-frequency rapid charge and discharge aluminum electrolytic capacitor comprises an anode foil, a cathode foil, a capacitor shell and electrolyte, porous electrolytic paper is arranged between the anode foil and the cathode foil, and oxide film layers are arranged on two sides of the anode foil. A stable and compact oxidation film is generated on the surface of the anode foil through the phosphoric acid formation liquid, so that the anode foil can withstand high-current impact, and the charging and discharging speed is greatly improved. According to the high-frequency rapid charging and discharging aluminum electrolytic capacitor for the servo motor and the manufacturing method, the high-frequency rapid charging and discharging aluminum electrolytic capacitor for the servo motor has excellent rapid charging and discharging performance, high voltage resistance, good temperature stability, long service life, high reliability and good heat dissipation performance.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic capacitors, and in particular to a high-frequency fast-charging and discharging aluminum electrolytic capacitor for a servo motor and a manufacturing method thereof. Background Art

[0002] In the rapid development of modern electronic technology, electronic devices are constantly evolving towards higher performance, smaller size and more multifunctionality. Among them, capacitors are indispensable key components in electronic circuits, and their performance has a vital impact on the operating efficiency and stability of the entire electronic device; in many application scenarios, such as high-frequency communication circuits, fast charging power modules, and power management systems in high-performance computing devices, extremely stringent requirements are placed on the charging and discharging speed of capacitors. Traditional electrolytic capacitors gradually expose many limitations in these scenarios.

[0003] The interface performance between the electrode material and the electrolyte of traditional electrolytic capacitors is poor, and the electrode surface lacks effective ion adsorption and desorption sites, resulting in slow ion migration during the charging and discharging process. For example, during high-frequency charging and discharging, traditional electrolytic capacitors cannot respond to charge changes in the circuit in a timely manner, which limits the operating frequency of the circuit. Moreover, the conductivity of the electrode material of traditional electrolytic capacitors is not ideal. Electrons encounter large resistance when transmitting inside the electrode, resulting in excessive heat loss, which not only reduces the charging and discharging efficiency, but also may affect the service life of the capacitor. In addition, the ion concentration and ion type of the electrolyte are not reasonably selected, and sufficient ion supply cannot be provided for rapid charging and discharging. At the same time, the structural design of traditional electrolytic capacitors does not fully consider the optimization of ion migration channels, resulting in ions being easily obstructed during the migration process. These problems combined make the charging and discharging time of traditional electrolytic capacitors long and inefficient, and cannot meet the requirements of modern electronic devices for rapid charging and discharging performance.

[0004] In summary, in view of the key role of existing electrolytic capacitors in electronic equipment, in order to solve the problems of long charging and discharging time and low efficiency, it is urgent to develop a high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motors and a manufacturing method. Summary of the invention

[0005] 1. Technical problems solved In view of the deficiencies in the prior art, the present invention provides a high-frequency fast-charging and discharging aluminum electrolytic capacitor for a servo motor and a manufacturing method thereof, which has the advantages of realizing fast charging and discharging, comprehensively improves the performance of the electrolytic capacitor, meets the demand of modern electronic equipment for high-performance electrolytic capacitors, and effectively overcomes the deficiencies in the prior art.

[0006] (II) Technical solution The above technical objectives of the present invention are achieved through the following technical solutions: a high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motors, comprising an anode foil, a cathode foil, a capacitor shell, and an electrolyte, wherein a porous electrolytic paper is arranged between the anode foil and the cathode foil, and an oxide film layer is arranged on both sides of the anode foil, and the capacitor shell is made of aluminum material; the oxide film layer is formed by an advanced electrochemical anodizing process combined with a micro-nano structure control technology, and is an oxide film layer with a high specific surface area. The oxide film layer has a unique microstructure, including holes and protrusions, so that the effective contact area with the electrolyte per unit area is increased by at least 50% compared with the traditional oxide film layer, providing more active sites for the adsorption and desorption of ions; the material of the cathode foil is aluminum with a purity of 99.99%, and the cathode foil ensures the electronic conduction efficiency during the fast charging and discharging process, and the core is first soaked in the working electrolyte and then sealed in the aluminum shell; the thickness of the passivation film is 0.1μm-0.3μm, and the passivation film can effectively prevent the corrosion of the cathode in a complex environment and improve the stability and service life of the capacitor.

[0007] The present invention is further configured as follows: the electrolyte contains a high concentration of ion conductive salt, and the concentration of the ion conductive salt in the electrolyte is not less than 0.5 mol / L to ensure sufficient ion supply and fast ion migration speed during rapid charge and discharge.

[0008] The present invention is further configured as follows: the capacitor housing is made of aluminum material with good insulation performance and mechanical strength, its dielectric constant is not higher than 3, and its compressive strength is not lower than 50MPa; a heat dissipation structure is provided on the surface of the capacitor housing, and the heat dissipation structure includes but is not limited to heat dissipation fins or heat dissipation grooves to ensure the heat dissipation efficiency of the capacitor during rapid charging and discharging.

[0009] In addition, the capacitor of the present invention also includes a sealing device, which is made of high-temperature resistant and corrosion-resistant materials to ensure that the electrolyte will not leak due to temperature changes or external environmental influences. The design of the sealing device also includes a safety valve. When the internal pressure exceeds the set value, the safety valve will automatically open to release the pressure, thereby protecting the capacitor from damage. In the manufacturing process of the capacitor, the present invention also adopts a special winding technology, which can ensure the uniformity of the electrode material and reduce the internal resistance, thereby improving the charging and discharging efficiency of the capacitor. The wound electrode sheets are precisely aligned and fixed to ensure that there is no relative displacement between the electrode sheets during the operation of the capacitor, thereby ensuring the long-term stability of the capacitor. In order to further improve the performance of the capacitor, the present invention also introduces an advanced aging test procedure. After the capacitor is manufactured, an aging test is performed by applying a voltage higher than the normal operating voltage to screen out potential early failure products, thereby ensuring that the capacitors delivered to users have higher reliability and consistency.

[0010] The present invention is further configured as follows: the lead-out ends of the anode foil and the cathode foil are made of tin-plated copper, and the thickness of the tin layer is between 5μm and 20μm, so as to improve the oxidation resistance and weldability of the lead-out ends. The connection between the lead-out ends and the electrodes is made by ultrasonic welding or laser welding, and the welding strength is not less than 20N.

[0011] In addition, the capacitor of the present invention is coated with a layer of special conductive polymer on the surface of the anode foil and the cathode foil. This polymer has excellent conductivity and chemical stability, and can effectively reduce the equivalent series resistance (ESR) of the capacitor, thereby further improving the charging and discharging efficiency. The coating process of the conductive polymer is carefully designed to ensure that the coating is uniform and tightly combined with the foil material, avoiding local hot spots that may occur during the operation of the capacitor and enhancing the thermal stability of the capacitor. In terms of capacitor packaging, the present invention adopts an innovative packaging structure design, which can not only effectively protect internal components, but also adapt to a wider temperature range and mechanical stress conditions. The packaging material is a composite material with high mechanical strength and good insulation performance, ensuring the reliable operation of the capacitor in harsh environments. During the packaging process, a moisture-proof layer is specially added to effectively prevent moisture penetration and extend the service life of the capacitor. In order to meet the specific requirements of capacitor performance in different application fields, the present invention also provides a variety of customized options. For example, the size, capacity and rated voltage of the capacitor can be adjusted according to customer needs to adapt to a specific electrical system design. In addition, the terminal design of the capacitor also supports a variety of connection methods, including but not limited to welding, screw fixing and clamping connection, providing users with great convenience and flexibility.

[0012] The present invention is further configured as follows: the electrolytic capacitor can normally perform rapid charge and discharge operations within a temperature range of -40°C to 85°C, and after 1000w charge and discharge cycles, its capacitance value retention rate is not less than 90%, ensuring reliable use under different environmental conditions. In addition, the electrolytic capacitor of the present invention adopts an advanced electrolyte formula, which can significantly reduce the internal resistance of the electrolyte, thereby improving the charging and discharging efficiency of the capacitor. In high-frequency applications, this low internal resistance characteristic is particularly important because it can reduce energy loss and improve the power density of the capacitor. At the same time, a special stabilizer is added to the electrolyte formula to inhibit the decomposition of the electrolyte under high temperature conditions, further enhancing the durability and stability of the capacitor. In the manufacturing process of the capacitor, the present invention also pays special attention to quality control. Each capacitor must undergo strict testing before leaving the factory, including detection of key parameters such as capacitance, equivalent series resistance (ESR), leakage current and insulation resistance. These tests ensure that each capacitor meets strict quality standards, thereby providing customers with consistent high-performance products.

[0013] In order to further improve the performance of the capacitor, the packaging material is selected from materials with excellent thermal stability and chemical stability to ensure that the capacitor can still maintain good performance under extreme temperatures and harsh environments. In the manufacturing process of the capacitor, the present invention also uses advanced automated production equipment, which can accurately control every link in the production process, from the ratio of materials to the assembly of capacitors. Each step strictly follows the quality standards. In this way, not only the production efficiency is improved, but also the quality consistency of the product is further guaranteed. In order to meet the needs of different application fields, the electrolytic capacitor of the present invention also provides a variety of specifications and capacity options. Users can choose the most suitable capacitor model according to the needs of actual applications, whether it is used for servo motors, inverters or other high-frequency fast In charge and discharge applications, the electrolytic capacitor of the present invention can provide stable and reliable performance support. In summary, the electrolytic capacitor of the present invention has many technical innovations. From material selection, packaging design to production process, each link reflects the pursuit of high performance and high reliability. The comprehensive application of these technologies makes the electrolytic capacitor of the present invention perform well in high-frequency and fast charge and discharge applications such as servo motors, and provides new solutions for related industries. The high-frequency and fast charge and discharge aluminum electrolytic capacitor for servo motors provided by the present invention has not only been innovated in technical solutions, but also optimized in material selection, manufacturing process and quality control. These comprehensive measures work together to ensure the stability and reliability of the capacitor in extreme environments and meet the needs of high-performance application fields such as servo motors.

[0014] The present invention is further configured as follows: the equivalent series resistance (ESR) of the electrolytic capacitor is not higher than 0.1Ω, and within the frequency range of 10kHz-1MHz, the capacitance value change rate does not exceed ±10% to ensure performance stability in high-frequency charging and discharging applications. In addition, the electrolytic capacitor of the present invention adopts advanced packaging technology to ensure the long-term reliability of the capacitor in high temperature and high humidity environments. The packaging material is made of special plastics that are resistant to high temperature and corrosion, which can effectively prevent the leakage of the electrolyte and maintain the stability of the structure under extreme temperature changes. During the production process, the present invention also pays special attention to the internal structure design of the capacitor. By optimizing the ratio of electrode materials and electrolytes, the equivalent series resistance (ESR) of the capacitor is further reduced, thereby improving the charging and discharging efficiency of the capacitor. At the same time, by accurately controlling the thickness and surface treatment of the electrodes, the capacitor has lower heat loss and higher energy density when working at high frequencies.

[0015] In order to further improve the reliability of the capacitor, the present invention also designs a redundant protection mechanism. In the capacitor group, each capacitor is equipped with an independent protection circuit. Once a capacitor is detected to be faulty, the protection circuit will immediately cut off the power supply of the faulty capacitor and transfer the load to other normally working capacitors to ensure the stable operation of the entire system. In the production process of the capacitor, the present invention also adopts advanced quality control processes. From the selection of raw materials to the testing of the final product, each step strictly follows the quality standards to ensure that each capacitor meets the design requirements. By using automated equipment and precision testing instruments, production efficiency and product consistency are significantly improved.

[0016] In summary, the innovations in design, materials and production process of the high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motors of the present invention ensure its excellent performance and long-term reliability in high-frequency fast charging and discharging applications such as servo motors. The comprehensive application of these technologies not only improves the performance indicators of the capacitor, but also provides a safer, more efficient and economical solution for related industries.

[0017] The present invention is further configured as follows: the anode foil is placed in a specific electrolyte, and anodized at a voltage of 10V-50V for 10 minutes-60 minutes, and the electrolyte temperature is maintained at 20°C-40°C to form a high specific surface area oxide film layer, the electrolyte comprises a mixed acid solution of sulfuric acid, oxalic acid and phosphoric acid, wherein the sulfuric acid concentration is 1mol / L-3mol / L, the oxalic acid concentration is 0.1mol / L-0.5mol / L, the phosphoric acid concentration is 0.2mol / L-0.8mol / L, and contains 0.01mol / L-0.05mol / L of additives, The additives are organic alcohols or organic amine compounds, which are used to improve the quality of the oxide film. After the anode foil is treated, the cathode foil is also very important. The cathode foil is cathodized in a specific electrolyte. The voltage range is set at 5V-20V, the treatment time is between 5 minutes and 30 minutes, and the electrolyte temperature is controlled at 15℃-35℃ to ensure the formation of a uniform and dense oxide film. The electrolyte is mainly composed of a solution containing chloride, and the chloride concentration is 0.5mol / L-1.5mol / L. At the same time, a small amount of fluoride is added, and the concentration is 0.05mol / L-0.2 mol / L, in order to enhance the corrosion resistance of the oxide film layer. After the surface treatment of the electrode foil is completed, the next step is the assembly process of the capacitor. First, the treated anode foil and cathode foil are wound into capacitor elements according to a specific spacing. During the winding process, ensure that there is an appropriate insulating isolation layer between the two foils to prevent short circuit. After the winding is completed, the capacitor element is immersed in the electrolyte and then sealed and packaged. The packaging material is usually selected from high-temperature resistant and corrosion-resistant plastic or metal materials to ensure that the capacitor can maintain stable performance in harsh environments. In order to further improve the performance of the capacitor, the present invention also introduces advanced packaging technology. By adopting a multi-layer packaging structure, the heat generated by the capacitor during high-frequency charging and discharging can be effectively dispersed, thereby reducing the internal temperature and extending the service life of the capacitor. In addition, a special heat dissipation design, such as a heat sink or a heat dissipation coating, is introduced in the packaging process to further improve the heat dissipation efficiency of the capacitor. Finally, the performance of the capacitor is verified through a series of tests, including but not limited to high-temperature aging tests, low-temperature impact tests, high-frequency charging and discharging tests, and voltage resistance tests. These tests ensure that the capacitor can still maintain stable performance under extreme conditions and meet the needs of high-frequency applications such as servo motors.

[0018] The present invention is further configured as follows: the electrolytic paper is a porous material composited with high-performance cellulose fibers, with a porosity of 65% to 75% and an average pore size of 0.8 μm to 1.5 μm. The pore structure enables the electrolyte to penetrate and remain perfectly therein, thereby enhancing the mechanical properties of the electrolytic paper, making its tensile strength not less than 12 N / cm, ensuring structural integrity, continuously providing a stable and low-resistance channel for ion migration, and improving the charge and discharge speed. The electrolytic paper also has good lyophilicity, and its contact angle with the electrolyte is less than 30°, ensuring that the electrolyte can be quickly and evenly distributed in the electrolytic paper.

[0019] In the process of manufacturing capacitors, the selection of electrolyte is also very important. The present invention adopts a special electrolyte formula, which is composed of an organic solvent and a conductive salt. The organic solvent has high boiling point and low vapor pressure characteristics, ensuring that the electrolyte will not evaporate easily in a high temperature environment, and the conductive salt provides high conductivity, thereby ensuring the high efficiency of the capacitor in the high-frequency charging and discharging process. In addition, specific stabilizers are added to the electrolyte. These stabilizers can effectively inhibit the decomposition of the electrolyte and extend the service life of the capacitor. In order to ensure the long-term stability and reliability of the capacitor, the present invention also emphasizes the design of the internal structure of the capacitor. The electrode material is made of high-purity aluminum foil, and the surface is specially treated to increase its surface area, thereby increasing the capacitance of the capacitor. The electrodes are separated by a diaphragm material. The diaphragm material not only needs to have good insulation properties, It should also have sufficient mechanical strength to withstand the pressure changes generated during the charging and discharging process. During the assembly process of the capacitor, automated equipment is used for precise control to ensure the uniform distribution of electrodes, diaphragms and electrolytes, thereby reducing internal defects and improving the overall performance of the capacitor. Finally, the present invention also involves capacitor testing and quality control processes. After the capacitor is packaged, a series of electrical performance tests will be carried out, including measurements of parameters such as capacitance, equivalent series resistance (ESR), and leakage current. These tests are not only carried out at room temperature, but also at high and low temperature environments to ensure the performance consistency of the capacitor under different temperature conditions. In addition, the capacitor will also undergo a long life test to verify its reliability in practical applications. Through these rigorous testing and quality control processes, the present invention ensures the high quality and high performance of the capacitor product.

[0020] The present invention is further configured as follows: a high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motor and a manufacturing method thereof are stacked in sequence by anode foil, electrolytic paper and cathode foil, wound into a core and then loaded into a capacitor housing, an electrolyte is injected and vacuum treated until the vacuum degree is lower than 100Pa and maintained for 10 minutes to 30 minutes before being sealed, a winding tension of 5N to 20N is applied during the winding process to ensure the compactness of the core, in order to further improve the performance of the capacitor, the present invention also pays special attention to the winding density of the core during the winding process, and ensures close contact between the electrodes by accurately controlling the winding tension and the diameter of the core, thereby reducing the internal resistance and improving the charging and discharging efficiency of the capacitor, in addition, the capacitor housing is made of high-voltage resistant material to withstand the high voltage stress that may occur during the high-frequency charging and discharging process, ensuring the safety and reliability of the capacitor, and in the selection of the electrolyte, the present invention adopts a A special electrolyte formula, which not only has good electrical conductivity but also has excellent chemical stability under high-frequency charging and discharging conditions. This electrolyte formula can effectively extend the service life of the capacitor and maintain good performance under high-temperature environments, thereby meeting the needs of servo motors under harsh working conditions. The present invention also relates to a packaging technology for capacitors. During the packaging process, advanced sealing technology is used to ensure that the capacitor does not leak electrolyte during long-term use. At the same time, the selection of packaging materials also takes into account compatibility with the electrolyte to prevent the performance of the capacitor from deteriorating due to material reaction. The high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motors provided by the present invention and the manufacturing method thereof significantly improve the performance and reliability of the capacitor by optimizing electrode materials, diaphragm materials, electrolyte formula and packaging technology, and meet the strict requirements of servo motors in high-frequency fast charging and discharging applications.

[0021] A method for manufacturing a high-frequency fast charging and discharging aluminum electrolytic capacitor for a servo motor, comprising: S1. Anode foil pretreatment: select aluminum foil with an aluminum purity of ≥99.7%, cut it into a specified size, place the anode foil in a mixed acid electrolyte containing sulfuric acid (concentration of 1mol / L-3mol / L), oxalic acid (concentration of 0.1mol / L-0.5mol / L) and phosphoric acid (concentration of 0.2mol / L-0.8mol / L) and containing 0.01mol / L-0.05mol / L organic alcohol or organic amine compound additives, and perform anodization treatment at a voltage of 10V-50V for 10 minutes-60 minutes, while maintaining the electrolyte temperature at 20℃-40℃, to form a high specific surface area oxide film layer with a thickness of 3μm-8μm and a roughness Ra value of 0.2μm-0.8μm; S2. Preparation of cathode foil: Select aluminum-copper alloy foil with a purity of 99.99%, cut it into a size matching that of the anode foil, and chemically treat its surface to form a passivation film with a thickness of 0.1μm-0.3μm; S3. Cutting and preparation of electrolytic paper: Cut the electrolytic paper made of high-performance cellulose fiber composite with a porosity of 65% to 75% and an average pore size of 0.8μm-1.5μm into appropriate sizes to ensure that it has good lyophilicity and a tensile strength of not less than 12N / cm; S4. Preparation of electrolyte: Preparation of main solvent: Mix organic solvents (one or more of ethylene carbonate (EC), propylene carbonate (PC), and γ-butyrolactone (GBL)) and low-viscosity organic solvents (one or more of dimethyl carbonate (DMC) and diethyl carbonate (DEC)) in a volume ratio of 1:1-3:1 to obtain a main solvent system. Solute dissolution: Dissolve high dissociation salt tetrafluoroborate (BF4 - ), tantalum pentoxide (Ta2O5), boric acid (H3BO3) or one or more thereof are mixed in a specific mass ratio to make the concentration of the solute in the electrolyte reach 0.8-2.5 mol / L, and under the protection of an inert gas (argon or nitrogen, flow rate 20-80 ml / min), the solute is slowly added to the main solvent, and stirred at 20°C-40°C, 400-1000 rpm for 40-120 minutes to fully dissolve it, and the temperature fluctuation is controlled within ±2°C during stirring. The stirring paddle is made of polytetrafluoroethylene or stainless steel, and the shape is anchor type, paddle type or turbine type, and repeated 2-3 times; S5. Assembly of capacitors: Rivet the lead strip at the center of one side of the oxide film treated surface of the anode foil. The lead strip is made of tin-plated copper with a tin layer thickness of 5μm-20μm. Ultrasonic welding or laser welding is used to ensure that the welding strength is not less than 20N. The electrolytic paper is placed between the anode foil and the cathode foil. A special winding process is used to expose 0.5-1mm of the cathode foil. A winding tension of 5N-20N is applied during the winding process. The wound core is placed in a capacitor housing made of aluminum material (with a dielectric constant of not more than 3 and a compressive strength of not less than 50MPa) and with a heat dissipation structure (heat dissipation fins or heat dissipation grooves). Ensure that the exposed part of the cathode foil is in good contact with the aluminum shell, and pad the negative foil at the riveted position of the cathode foil. S6. Packaging and testing: Inject the prepared electrolyte into the capacitor casing, then perform vacuum treatment to make the vacuum degree lower than 100Pa and maintain it for 10-30 minutes, then seal it, and perform aging test on the finished capacitor to test its fast charging and discharging performance in the temperature range of -40℃-85℃. It is required that the capacitance retention rate after 1000w charge and discharge cycles is not less than 90%; the test equivalent series resistance (ESR) is not higher than 0.1Ω, and the capacitance value change rate does not exceed ±10% in the frequency range of 10kHz-1MHz, and qualified products are screened out.

[0022] (III) Beneficial effects Compared with the prior art, the present invention provides a high-frequency fast charging and discharging aluminum electrolytic capacitor for a servo motor and a manufacturing method thereof, which has the following beneficial effects: The high-frequency fast-charging and discharging aluminum electrolytic capacitor for the servo motor has excellent fast charging and discharging performance: the high specific surface area oxide film layer of the anode foil and the electrolytic paper with a special structure work together to greatly improve the adsorption and desorption efficiency and migration speed of ions, so that the capacitor can respond quickly during the charging and discharging process, significantly shortening the charging and discharging time; the high-concentration and specific composition of the electrolyte provides sufficient supply and fast migration conditions for ions, further improving the charging and discharging speed; High voltage resistance: The precise thickness control and unique microstructure of the anode foil oxide film effectively enhance the voltage resistance of the capacitor, enabling it to work stably at higher voltages and broaden its application range; Good temperature stability: electrolytic capacitors can perform fast charge and discharge operations normally in a wide temperature range of -40℃-85℃, thanks to the reasonable selection and optimized design of materials for each component, such as the high conductivity material of the cathode foil, the stable composition of the electrolyte and the good performance of the electrolytic paper, which ensures reliable use in different temperature environments; Long life and high reliability: The passivation film of the cathode foil effectively prevents cathode corrosion, the quality of the anode foil oxide film is stable, and the conductive glue is resistant to electrolyte corrosion. These factors work together to ensure that the capacitor has a capacitance retention rate of no less than 90% after 1000w charge and discharge cycles, and has the characteristics of long life and high reliability; low equivalent series resistance characteristics (no higher than 0.1Ω), within the frequency range of 10kHz-1MHz, the capacitance value change rate does not exceed ±10%, reducing energy loss and heat generation during charging and discharging, and improving the stability and reliability of the capacitor, especially suitable for high-frequency charging and discharging applications; Good heat dissipation performance: The heat dissipation structure design of the capacitor shell can promptly dissipate the heat generated during the charging and discharging process, avoiding performance degradation or damage due to overheating, and further improving the stability and service life of the capacitor BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The invention discloses a method for manufacturing a high-frequency fast charging and discharging aluminum electrolytic capacitor. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1 like Figure 1As shown, a high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motors includes an anode foil, a cathode foil, a capacitor housing, and an electrolyte. A porous electrolytic paper is arranged between the anode foil and the cathode foil. An oxide film layer is arranged on both sides of the anode foil. The surface of the cathode foil is chemically treated and provided with a passivation film, which greatly improves the charging and discharging speed and significantly enhances the withstand voltage performance of the capacitor. The oxide film layer is formed by an advanced electrochemical anodizing process combined with a micro-nano structure control technology. It is an oxide film layer with a high specific surface area. The oxide film layer has a unique microstructure, including holes and protrusions, so that the effective contact area with the electrolyte per unit area is increased by at least 50% compared with the traditional oxide film layer, providing more active sites for the adsorption and desorption of ions. point; the material of cathode foil is 99.99% pure aluminum, of which magnesium content is 1%-3%. Cathode foil ensures the efficiency of electron conduction during rapid charge and discharge. The core is first soaked in working electrolyte and then sealed in aluminum shell; the thickness of passivation film is 0.1μm-0.3μm. Passivation film can effectively prevent corrosion of cathode in complex environment and improve the stability and service life of capacitor. Electrode and electrolytic paper: There are oxide film layers on both sides of anode foil, which are formed by advanced electrochemical anodizing process combined with micro-nano structure control technology; its thickness is precisely controlled between 3μm-8μm, and roughness Ra value is in the range of 0.2μm-0.8μm; this high specific surface area oxide film layer has unique microstructure The structure includes holes and protrusions, which increases the effective contact area with the electrolyte per unit area by at least 50% compared with the traditional oxide film layer, providing more active sites for the adsorption and desorption of ions, which not only greatly improves the charging and discharging speed, but also significantly enhances the voltage resistance of the capacitor; the material of the cathode foil is 99.99% pure aluminum (with a magnesium content of 1%-3%), ensuring the efficiency of electronic conduction during rapid charging and discharging; the surface of the cathode foil is chemically treated with a passivation film with a thickness of 0.1μm-0.3μm, which can effectively prevent the corrosion of the cathode in complex environments and improve the stability and service life of the capacitor; a porous electrolytic paper is provided between the anode foil and the cathode foil, and the electrolytic paper is made of high-performance fiber The porous material made of cellulose fiber has a porosity of 65%-75% and an average pore size of 0.8μm-1.5μm. The pore structure allows the electrolyte to penetrate and remain perfectly in it, enhancing the mechanical properties of the electrolytic paper, making its tensile strength not less than 12N / cm, ensuring the integrity of the structure, and continuously providing a stable and low-resistance channel for ion migration, thereby increasing the charging and discharging speed. The electrolytic paper also has good lyophilicity, and its contact angle with the electrolyte is less than 30°, ensuring that the electrolyte can be quickly and evenly distributed in the electrolytic paper; the electrolyte: contains a high concentration of ion conductive salt, the concentration of the ion conductive salt in the electrolyte is not less than 0.5mol / L, and the cations in the ion conductive salt have a radius of 0.1nm-0.3nm alkali metal ions or their composite ions, anions are complex anions with high dissociation degree and stable chemical properties, such as hexafluorophosphate, bis(trifluoromethanesulfonyl imide), etc., to ensure sufficient ion supply and fast ion migration speed during rapid charge and discharge; capacitor shell and lead-out terminal: the capacitor shell is made of aluminum material with good insulation performance and mechanical strength, with a dielectric constant not higher than 3 and a compressive strength not lower than 50MPa. The surface is provided with a heat dissipation structure, such as heat dissipation fins or heat dissipation grooves, to ensure the heat dissipation efficiency of the capacitor during rapid charge and discharge; the lead-out terminals of the anode foil and cathode foil are made of tin-plated copper, with a tin layer thickness of 5μm-20μm, to improve the oxidation resistance and weldability of the lead-out terminals. The connection between the lead-out terminals and the electrodes is made of ultrasonic welding or laser welding, with a welding strength of not less than 20N. .

[0026] This data comparison table clearly demonstrates the advantages of the present invention over traditional electrolytic capacitors in multiple key performance indicators, highlighting the characteristics of fast charging and discharging, high stability, and good environmental adaptability. In practical applications, the table content can be improved based on more detailed and accurate experimental data.

[0027] A method for manufacturing a high-frequency fast charging and discharging aluminum electrolytic capacitor for a servo motor, comprising: S1. Anode foil pretreatment: select aluminum foil with an aluminum purity of ≥99.7%, cut it into a specified size, place the anode foil in a mixed acid electrolyte containing sulfuric acid (concentration of 1mol / L-3mol / L), oxalic acid (concentration of 0.1mol / L-0.5mol / L) and phosphoric acid (concentration of 0.2mol / L-0.8mol / L) and containing 0.01mol / L-0.05mol / L organic alcohol or organic amine compound additives, and perform anodization treatment at a voltage of 10V-50V for 10 minutes-60 minutes, while maintaining the electrolyte temperature at 20℃-40℃, to form a high specific surface area oxide film layer with a thickness of 3μm-8μm and a roughness Ra value of 0.2μm-0.8μm; S2. Preparation of cathode foil: Select aluminum-copper alloy foil with a purity of 99.99%, cut it into a size matching that of the anode foil, and chemically treat its surface to form a passivation film with a thickness of 0.1μm-0.3μm; S3. Cutting and preparation of electrolytic paper: Cut the electrolytic paper, which is a composite of high-performance cellulose fibers, with a porosity of 65%-75% and an average pore size of 0.8μm-1.5μm, into a suitable size to ensure that it has good lyophilicity and a tensile strength of not less than 12N / cm; S4. Preparation of electrolyte: Preparation of main solvent: Mix organic solvent (one or more of ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (GBL)) and low viscosity organic solvent (one or more of dimethyl carbonate (DMC), diethyl carbonate (DEC)) in a volume ratio of 1:1-3:1 to obtain a main solvent system. Dissolve the solute: Dissolve high dissociation degree salt (tetrafluoroborate (BF4 - ), tantalum pentoxide (Ta2O5), boric acid (H3BO3) or one or more thereof are mixed in a specific mass ratio to make the concentration of the solute in the electrolyte reach 0.8-2.5 mol / L, and under the protection of an inert gas (argon or nitrogen, flow rate 20-80 ml / min), the solute is slowly added to the main solvent, and stirred at 20°C-40°C, 400-1000 rpm for 40-120 minutes to fully dissolve it, and the temperature fluctuation is controlled within ±2°C during stirring. The stirring paddle is made of polytetrafluoroethylene or stainless steel, and the shape is anchor type, paddle type or turbine type, and repeated 2-3 times; S5. Assembly of capacitors: Rivet the lead strip at the center of one side of the oxide film treated surface of the anode foil. The lead strip is made of tin-plated copper with a tin layer thickness of 5μm-20μm. Ultrasonic welding or laser welding is used to ensure that the welding strength is not less than 20N. The electrolytic paper is placed between the anode foil and the cathode foil. A special winding process is used to expose 0.5-1mm of the cathode foil. A winding tension of 5N-20N is applied during the winding process. The wound core is placed in a capacitor housing made of aluminum material (with a dielectric constant of not more than 3 and a compressive strength of not less than 50MPa) and with a heat dissipation structure (heat dissipation fins or heat dissipation grooves). Ensure that the exposed part of the cathode foil is in good contact with the aluminum shell, and pad the negative foil at the riveted position of the cathode foil. S6. Packaging and testing: Inject the prepared electrolyte into the capacitor casing, then perform vacuum treatment to make the vacuum degree lower than 100Pa and maintain it for 10-30 minutes, then seal it, and perform aging test on the finished capacitor to test its fast charging and discharging performance in the temperature range of -40℃-85℃. It is required that the capacitance retention rate after 1000w charge and discharge cycles is not less than 90%; the test equivalent series resistance (ESR) is not higher than 0.1Ω, and the capacitance value change rate does not exceed ±10% in the frequency range of 10kHz-1MHz, and qualified products are screened out.

[0028] Compared with the prior art, the fast charging and discharging electrolytic capacitor of the present invention has the following significant advantages: fast charging and discharging speed, which can meet the requirements of high-frequency circuits and fast charging and discharging power supplies for fast charging and discharging performance of capacitors, and improve the overall working efficiency of electronic equipment. The reasonable structural design and electrolyte composition improve the voltage resistance and stability of the capacitor, extend its service life, and reduce the probability of failure during use. Another implementation plan is to further optimize the external protection measures of the capacitor on the basis of the basic plan.

[0029] Example 2 The invention relates to a high-frequency fast charging and discharging aluminum electrolytic capacitor for a servo motor. The core lies in developing a highly stable branched carboxylate system electrolyte, with multi-branched carboxylate ammonium salt as the main solute, and adding silicon dioxide, diethylene glycol and polyethylene glycol to increase the flash voltage, and using a new composite dehydrogenating agent to achieve the high reliability and low gas production requirements of the capacitor. In addition, a high-purity negative foil with an aluminum purity of ≥99.7% is selected, and the formation voltage is ≥5V. The WD series low-density high-voltage electrolytic paper (thickness 60-80μm) is used, which not only reduces the capacitor impedance but also meets its high withstand voltage requirements. The lead strip is riveted at the middle position of the folded positive aluminum foil to reduce the capacitor impedance and reduce the heat generated by the capacitor during current impact. A special winding process of "exposing" the negative electrode is adopted, and the negative foil at the bottom of the core is exposed by 0.5-1mm. After being loaded into an aluminum shell, the negative foil is in direct contact with the aluminum shell to improve the heat dissipation of the capacitor. The negative foil is padded at the riveted position of the negative electrode. The "capacity increase" at the position is carried out to improve its ability to withstand the impact of feedback current. These technical innovations include: developing a highly stable multi-branched carboxylic acid ammonium salt high-voltage welding sheet working electrolyte to improve the charging and discharging characteristics of the capacitor at high frequency; using high-purity pressurized negative foil to suppress the parameter degradation of the capacitor negative electrode due to the impact of feedback current; using a special winding process with the "exposed" negative electrode to improve the heat dissipation of the capacitor; padding the negative foil at the riveted position of the negative electrode to improve its ability to withstand the impact of feedback current. By developing a highly stable branched carboxylate system electrolyte, the charging and discharging efficiency of the capacitor at high frequency is significantly improved, the heating phenomenon of the capacitor is reduced, and the service life of the capacitor is extended. The selection of high-purity aluminum foil and a specially designed winding process not only reduces the internal resistance of the capacitor and improves its voltage resistance, but also effectively improves the heat dissipation performance of the capacitor, allowing the capacitor to work stably over a wider temperature range.

[0030] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. After reading this specification, those skilled in the art can make non-creative modifications to the present embodiment as needed. Although the embodiments of the present invention have been shown and described, it is understandable to those of ordinary skill in the art that various changes, modifications, substitutions and deformations may be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-frequency fast charging and discharging aluminum electrolytic capacitor for a servo motor, comprising an anode foil, a cathode foil, a capacitor housing, and an electrolyte, characterized in that: A porous electrolytic paper is arranged between the anode foil and the cathode foil, an oxide film layer is arranged on both sides of the anode foil, and the capacitor shell is made of aluminum material; The oxide film layer is formed by an advanced electrochemical anodization process combined with micro-nanostructure control technology. It is a high specific surface area oxide film layer with a unique microstructure, including holes and protrusions, which increases the effective contact area with the electrolyte per unit area by at least 50% compared with the traditional oxide film layer, providing more active sites for the adsorption and desorption of ions. The cathode foil is made of aluminum with a purity of 99.99%. The cathode foil ensures the electron conduction efficiency during rapid charge and discharge. The core is first soaked in the working electrolyte and then sealed in the aluminum shell.

2. The high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motor according to claim 1, characterized in that: The electrolyte contains a high concentration of ion-conducting salt, and the concentration of the ion-conducting salt in the electrolyte is not less than 0.5 mol / L to ensure sufficient ion supply and fast ion migration speed during rapid charge and discharge.

3. The high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motor according to claim 1, characterized in that: The capacitor housing is made of aluminum material with good insulation performance and mechanical strength, with a dielectric constant of no more than 3 and a compressive strength of no less than 50 MPa. A heat dissipation structure is provided on the surface of the capacitor housing, and the heat dissipation structure includes but is not limited to heat dissipation fins or heat dissipation grooves to ensure the heat dissipation efficiency of the capacitor during rapid charging and discharging.

4. The high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motor according to claim 1, characterized in that: The lead-out ends of the anode foil and cathode foil are made of tin-plated copper, and the thickness of the tin layer is between 5μm and 20μm to improve the oxidation resistance and weldability of the lead-out ends. The connection between the lead-out ends and the electrodes is made by ultrasonic welding or laser welding, and the welding strength is not less than 20N.

5. The high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motor according to claim 1, characterized in that: The electrolytic capacitor can perform rapid charge and discharge operations normally within the temperature range of -40℃-85℃, and after 1000w charge and discharge cycles, its capacitance value retention rate is not less than 90%, ensuring reliable use under different environmental conditions.

6. The high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motor according to claim 1, characterized in that: The equivalent series resistance (ESR) of the electrolytic capacitor is not higher than 0.1Ω, and the capacitance value change rate does not exceed ±10% in the frequency range of 10kHz-1MHz to ensure performance stability in high-frequency charging and discharging applications.

7. The high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motor according to claim 1, characterized in that: The anode foil is placed in a specific electrolyte and anodized at a voltage of 10V-50V for 10 minutes-60 minutes. The electrolyte temperature is maintained at 20°C-40°C to form a high specific surface area oxide film layer. The electrolyte contains a mixed acid solution of sulfuric acid, oxalic acid and phosphoric acid, wherein the concentration of sulfuric acid is 1mol / L-3mol / L, the concentration of oxalic acid is 0.1mol / L-0.5mol / L, the concentration of phosphoric acid is 0.2mol / L-0.8mol / L, and contains 0.01mol / L-0.05mol / L of additives, which are organic alcohols or organic amine compounds for improving the quality of the oxide film layer.

8. The high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motor according to claim 1, characterized in that: The electrolytic paper is a porous material composited with high-performance cellulose fibers, with a porosity of 65%-75% and an average pore size of 0.8μm-1.5μm. The pore structure enables the electrolyte to penetrate and remain perfectly therein, thereby enhancing the mechanical properties of the electrolytic paper and making its tensile strength not less than 12N / cm, ensuring structural integrity, continuously providing a stable and low-resistance channel for ion migration, and improving the charge and discharge speed. The electrolytic paper also has good lyophilicity, and its contact angle with the electrolyte is less than 30°, ensuring that the electrolyte can be quickly and evenly distributed in the electrolytic paper.

9. The high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motor according to claim 1, characterized in that: The high-frequency fast charging and discharging aluminum electrolytic capacitor for servo motors is composed of anode foil, electrolytic paper and cathode foil stacked in sequence, wound into a core and then loaded into the capacitor shell. During the winding process, a winding tension of 5N-20N is applied to ensure the compactness of the core.

10. A method for manufacturing a high-frequency fast-charging and discharging aluminum electrolytic capacitor for a servo motor as claimed in claims 1 to 9, characterized in that: include: S1. Anode foil pretreatment: select aluminum foil of specified size, place the anode foil in a mixed acid electrolyte containing sulfuric acid, oxalic acid and phosphoric acid and containing organic alcohol or organic amine compound additives, perform anodization treatment at a voltage of 10V-50V for 10 minutes-60 minutes, and keep the electrolyte temperature at 20℃-40℃ to form an oxide film with high specific surface area; S2. Preparation of cathode foil: Select aluminum-copper alloy foil with a purity of 99.99%, cut it into a size matching that of the anode foil, and chemically treat its surface to form a passivation film with a thickness of 0.1μm-0.3μm; S3. Cutting and preparation of electrolytic paper: Cut the electrolytic paper, which is made of high-performance cellulose fiber composite, has a porosity of 65% to 75% and an average pore size of 0.8μm-1.5μm, into a suitable size to ensure that it has good lyophilicity and a tensile strength of not less than 12N / cm; S4, electrolyte preparation: organic solvent and low viscosity organic solvent are mixed in a volume ratio of 1:1-3:1 to obtain a main solvent system, solute dissolution: high dissociation degree salts are mixed in a specific mass ratio to make the concentration of the solute in the electrolyte reach 0.8-2.5 mol / L, under the protection of inert gas, the solute is slowly added to the main solvent, stirred at 20℃-40℃, 400-1000rpm for 40-120 minutes to fully dissolve it, the temperature fluctuation during stirring is controlled within ±2℃, the stirring paddle is made of polytetrafluoroethylene or stainless steel, and the shape is anchor type, paddle type or turbine type, and repeated 2-3 times; S5. Capacitor assembly: Rivet the lead bar at the center of one side of the oxide film treated surface of the anode foil. The lead bar is made of tin-plated copper with a tin layer thickness of 5μm-20μm. Ultrasonic welding or laser welding is used to ensure that the welding strength is not less than 20N. The electrolytic paper is placed between the anode foil and the cathode foil. A special winding process is used to expose 0.5-1mm of the cathode foil. A winding tension of 5N-20N is applied during the winding process. The wound core is placed in a capacitor housing made of aluminum material with a heat dissipation structure to ensure that the exposed part of the cathode foil is in good contact with the aluminum shell, and the negative foil is padded at the riveted position of the cathode foil. S6. Packaging and testing: Inject the prepared electrolyte into the capacitor shell, then perform vacuum treatment to make the vacuum degree lower than 100Pa and maintain it for 10 to 30 minutes, then seal it, and perform aging test on the finished capacitor to test its fast charging and discharging performance in the temperature range of -40℃-85℃. It is required that the capacitance retention rate after 1000w charge and discharge cycles is not less than 90%; the test equivalent series resistance is not higher than 0.1Ω, and the capacitance value change rate in the frequency range of 10kHz-1MHz does not exceed ±10%, and qualified products are screened out.

Images