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During the operation of equipment such as storage batteries and electrolytic capacitors, the aging of plates is a key issue affecting their performance and service life, and the sulfation of plates is one of the important factors leading to aging. Plate vulcanization not only reduces the charging and discharging efficiency of the equipment, but also shortens its overall service life, causing many inconveniences and economic losses to industrial production and daily life. Therefore, in-depth research on the repair and prevention measures of plate sulfation has important practical significance. This article will elaborate in detail from multiple aspects such as the principle of plate vulcanization, repair methods, and preventive measures, providing solutions of reference value for related fields.

1. Analysis of the Principle of Plate Vulcanization

Plate sulfation refers to the phenomenon where the active substance lead sulfate on the plates crystallizes under certain conditions, forming coarse and insoluble lead sulfate crystals, thereby hindering the normal progress of electrochemical reactions. During the normal charging and discharging process, the active substances on the plates constantly switch between lead sulfate and lead oxide. However, when the battery or electrolytic capacitor is in an adverse state such as over-discharge, long-term idleness, excessively high electrolyte concentration or abnormal temperature, this conversion process will become unbalanced.

Under over-discharge conditions, the active substances on the plates will be largely converted into lead sulfate. Due to the overly rapid reaction rate, lead sulfate cannot be evenly distributed in time and will form larger crystal particles on the surface of the plates. When idle for a long time, lead sulfate on the plates will gradually accumulate and grow due to the lack of effective electrochemical reactions. Excessive concentration of the electrolyte will change the equilibrium of the electrochemical reaction and promote the formation and growth of lead sulfate crystals. Abnormal temperatures, whether too high or too low, will affect the rate and direction of electrochemical reactions and increase the risk of plate sulfation. These large lead sulfate crystals not only occupy the active material space on the plates, but also increase the resistance of the plates and reduce their conductivity, thereby leading to a decline in equipment performance and problems such as inability to charge and reduced discharge capacity.

2. Repair Methods for sulfide Plates

(1) Chemical repair method

Chemical remediation is a method that utilizes chemical agents to react with sulfated lead sulfate crystals, converting them into soluble substances or reactivating active substances. Common chemical repair agents include electrolytes containing specific additives, organic compound solutions, etc. For instance, certain additives can reduce the solubility product of lead sulfate, promoting the dissolution of coarse lead sulfate crystals and their re-participation in electrochemical reactions. When using the chemical repair method, the old electrolyte in the equipment needs to be drained first, and then an electrolyte containing the repair agent is injected. The repair agent will undergo a chemical reaction with the lead sulfate crystals on the plates, gradually dissolving them or converting them into active substances. This method is relatively simple to operate, but the repair effect is greatly affected by factors such as the type and concentration of the repair agent and the reaction time. Moreover, some chemical repair agents may cause certain corrosion to the plates and equipment, so they need to be selected and used with caution.

(2) Physical restoration method

Pulse repair: Pulse repair is an effective repair method based on electrochemical and physical principles. It breaks the structure of lead sulfate crystals by applying high-frequency pulse currents to the sulfated plates and taking advantage of the instantaneous high voltage and high frequency characteristics of the pulse currents. Under the action of pulsed current, the lead sulfate crystals on the surface of the plates are affected by the rapidly changing electric field, and the chemical bonds inside the crystals are broken, thus gradually dissolving them and reconverting them into active substances. Pulse repair has the advantages of high repair efficiency and minimal damage to the plates. It can be carried out without disassembling the equipment and does not affect the normal use of the equipment. Meanwhile, pulse repair can also improve the electrochemical performance of the plates, enhance the charging and discharging efficiency and service life of the equipment.

Heating repair: Heating repair is a process that utilizes the influence of temperature on the properties of substances to restore sulfide plates. Appropriately increasing the temperature can enhance the solubility of lead sulfate in the electrolyte and accelerate its dissolution process. During the heating process, the lead sulfate crystals on the plates absorb heat, the molecular movement intensifies, the crystal structure becomes unstable, and thus gradually dissolves. However, heating repair requires strict control of temperature and heating time. Excessively high temperatures may cause deformation of the plates, shedding of active substances, and even damage other components of the equipment. If the temperature is too low, the ideal repair effect cannot be achieved. Generally speaking, the heating temperature should be controlled within an appropriate range, and at the same time, it should be accompanied by proper stirring or circulation of the electrolyte to ensure uniform repair effects.

(3) Comprehensive Restoration method

The comprehensive restoration method is a way that combines the chemical restoration method and the physical restoration method. First, use chemical repair agents to soften and dissolve part of the lead sulfate crystals, reducing the strength and stability of the crystals. Then, utilize physical methods such as pulse repair to further destroy the crystal structure, making it completely dissolve and transform into active substances. This method gives full play to the advantages of both repair methods and can repair severely vulcanized plates more effectively. For instance, when repairing some battery plates that have been idle for a long time and have a high degree of sulfation, an electrolyte containing a specific chemical repair agent is first injected to react with lead sulfate crystals for a period of time. After the crystals partially dissolve, pulse repair is carried out. Through this comprehensive repair method, the success rate of repair can be significantly improved and the performance of the plates can be restored.

3. Preventive Measures for Plate Sulfation

(1) Reasonable use and maintenance

Avoid over-discharge: During the operation of the equipment, the depth of discharge must be strictly controlled to prevent excessive discharge. Over-discharge will cause a large amount of active substances on the plates to be converted into lead sulfate, increasing the risk of sulfidation. Therefore, it is necessary to set an appropriate discharge termination voltage according to the specifications and user manual of the equipment. When the battery level of the equipment approaches the discharge termination voltage, it should be charged in time to prevent over-discharge.

Regular charging: For equipment that has been idle for a long time, regular charging should be carried out to prevent sulfation of the plates. Even when the equipment is not in use, the electrochemical reactions inside will proceed slowly, causing the active substances on the plates to gradually vulcanize. Regular charging can promptly convert lead sulfate on the plates into active substances, maintaining the normal performance of the plates. Generally speaking, idle equipment should undergo a full charge and discharge cycle at regular intervals, which can effectively prevent sulfation of the plates.

Correct charging: Choosing the appropriate charging method and charging equipment is crucial for preventing sulfation of the plates. The charging current and voltage that meet the requirements of the equipment should be adopted to avoid overcharging and undercharging. Overcharging will cause the plates to heat up, accelerate the aging and shedding of active substances, and also promote the formation of lead sulfate crystals. Undercharging will cause the active substances on the plates to not be fully transformed, and also increase the possibility of sulfidation. In addition, during the charging process, pay attention to observing the temperature and charging status of the device. If any abnormality is found, stop charging immediately and check the cause.

(2) Electrolyte Management

Control the concentration of the electrolyte: The concentration of the electrolyte has a significant impact on the sulfation of the plates. Excessively high electrolyte concentration will alter the equilibrium of electrochemical reactions, promoting the formation and growth of lead sulfate crystals. Therefore, it is necessary to strictly control the concentration of the electrolyte within an appropriate range based on the type of equipment and the usage environment. When preparing the electrolyte, it is necessary to accurately mix it in accordance with the prescribed proportion, and regularly detect and adjust the concentration of the electrolyte.

Maintain the electrolyte level: If the electrolyte level is too low, part of the plates will be exposed to the air, leading to oxidation and sulfidation of the plates. Therefore, it is necessary to regularly check the electrolyte level, replenish distilled water or dedicated electrolyte in time, and ensure that the plates are completely immersed in the electrolyte. At the same time, when replenishing the electrolyte, it is necessary to be careful to avoid impurities entering to prevent damage to the equipment.

(3) Environmental Control

Temperature control: Abnormal temperature is one of the important factors leading to sulfation of the plates. Excessively high temperatures will accelerate the progress of electrochemical reactions and promote the rapid growth of lead sulfate crystals. Too low a temperature will reduce the rate of electrochemical reactions, making it difficult for lead sulfate to be converted into active substances. Therefore, the equipment should be placed in an environment with suitable temperature for operation and storage. In high-temperature environments, measures such as ventilation and heat dissipation can be taken to lower the temperature of the equipment. In low-temperature environments, insulation materials or heating devices can be used to keep the equipment temperature within an appropriate range.

Humidity control: A humid environment can cause rust and corrosion on the equipment casing and plates, affecting the performance and service life of the equipment. Therefore, it is necessary to keep the storage and usage environment of the equipment dry and prevent moist air from entering the interior of the equipment. Desiccants, dehumidification equipment, etc. can be used to control the environmental humidity and ensure that the equipment is in a dry environment.

4. Conclusion

Plate vulcanization is one of the main causes of plate aging, which seriously affects the performance and service life of the equipment. By thoroughly understanding the principle of plate sulfation, mastering effective repair methods such as chemical repair, physical repair and comprehensive repair, and taking reasonable preventive measures, including rational use and maintenance, electrolyte management and environmental control, etc., the problem of plate sulfation can be effectively solved, the service life of equipment can be prolonged and maintenance costs can be reduced. In practical applications, appropriate repair and preventive measures should be selected based on the specific conditions of the equipment and the degree of vulcanization to ensure the normal operation and efficient performance of the equipment. With the continuous development of technology, more advanced and efficient plate vulcanization repair and prevention technologies may emerge in the future, providing stronger support for the development of related fields.