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 Abstract

This article conducts an in-depth discussion on the issue of plate sulfation in forklift lead-acid batteries, elaborating in detail on the principle and hazards of plate sulfation, comprehensively analyzing various factors leading to sulfation, and proposing effective maintenance methods to prevent plate sulfation from multiple dimensions. The aim is to provide scientific and practical references for the maintenance of forklift lead-acid batteries, extend the service life of the batteries, and reduce the usage cost. Ensure the efficient and stable operation of forklift operations.

1. Introduction

In the modern logistics and warehousing industry, forklifts, as indispensable handling equipment, mainly rely on lead-acid batteries for their power source. Lead-acid batteries have advantages such as low cost, mature technology, and stable charging and discharging performance. However, during use, sulfation of the plates is a common problem that seriously affects their performance and lifespan. Sulfation of the plates can lead to a decrease in the capacity of the battery, an increase in internal resistance, a reduction in charging and discharging efficiency, and even premature scrapping of the battery, thereby increasing the operating costs of enterprises. Therefore, a thorough understanding of the mechanism of plate sulfation and the mastery of effective maintenance methods are of great significance for ensuring the normal operation of forklift lead-acid batteries and extending their service life.

2. The Principle and Hazards of Sulfation of Lead-Acid Battery Plates

(1) Vulcanization Principle

During the normal charging and discharging process of lead-acid batteries, the active substances on the plates (mainly lead dioxide and spongy lead) undergo chemical reactions with sulfuric acid in the electrolyte, achieving the mutual conversion of electrical energy and chemical energy. When a battery is in an improper usage or storage state, a layer of hard and dense lead sulfate crystals will gradually form on the surface of the plates. These crystal particles are large and difficult to be reconverted into active substances during normal charging. This phenomenon is known as plate sulfation. Its essence is the abnormal crystallization process of lead sulfate on the plates, which is usually caused by the battery being in a state of undercharging, overdischarging for a long time, having an electrolyte density that is too high or too low, or an unsuitable temperature.

(2) Hazards

1. ** Capacity decline ** : The lead sulfate crystals formed by sulfidation occupy the space of the active substances on the plates that were originally used for chemical reactions, reducing the effective area for participating in electrochemical reactions, thereby significantly lowering the capacity of the battery. During operation, forklifts may experience a significant reduction in their endurance, failing to meet the requirements of normal working hours.

2. ** Increased internal resistance ** : The coarse lead sulfate crystals have poor electrical conductivity, increasing the resistance of current passing through the plates and resulting in an increase in the internal resistance of the battery. This will cause insufficient current output when the forklift starts, making it difficult to start. At the same time, more heat will be generated during the discharge process, accelerating the aging and damage of the internal components of the battery.

3. ** Reduced charging and discharging efficiency ** : Due to the difficulty of the sulfated plates to fully revert to active substances, during charging, the battery's ability to accept electrical energy weakens, and a longer charging time is required to reach a fully charged state. However, during discharge, the stored electrical energy cannot be fully released, resulting in a decrease in energy utilization rate and an increase in the consumption and usage cost of electrical energy.

4. ** Shortened service life ** : Sulfation of the plates can cause irreversible damage to the active material structure of the plates. As the degree of sulfation intensifies, the performance of the battery will continuously deteriorate, eventually leading to premature scrapping and frequent battery replacement, which brings a considerable economic burden to the enterprise.

3. Factors Causing Sulfation of Lead-acid Battery Plates in Forklifts

(1) Improper charging management

1. ** Undercharging ** : In the actual use of forklifts, due to busy work tasks, operators may neglect the charging status of the battery and put it back into use without fully charging it. When in a state of undercharging for a long time, the lead sulfate on the plates cannot be completely converted into active substances and gradually accumulates to form sulfide crystals. For instance, some enterprises, in order to enhance the operational efficiency of forklifts, stop charging when there is still a considerable amount of battery power left. Frequent such operations significantly increase the risk of sulfation of the plates.

2. ** Overcharging ** : Although overcharging is not as common as undercharging, it can also occur if the control accuracy of the charging device is insufficient or the Settings are unreasonable. Overcharging will cause excessive decomposition of water in the electrolyte, generating a large amount of gas, accelerating the shedding of active substances on the plates, and also promoting the formation of lead sulfate crystals, intensifying the sulfation of the plates.

(2) Environmental factors of use

1. ** Temperature influence ** : Lead-acid batteries are relatively sensitive to temperature. In low-temperature environments, the fluidity of the electrolyte deteriorates, the electrochemical reaction rate slows down, the charging and discharging performance of the battery declines, and it is prone to insufficient charging, which in turn leads to sulfation of the plates. In high-temperature environments, the evaporation rate of the electrolyte increases, its concentration rises, and the corrosive effect of sulfuric acid on the plates intensifies, which also speeds up the sulfidation process of the plates. For instance, in the cold winter, when forklifts are operating outdoors, the performance of the battery significantly declines. If appropriate insulation measures are not taken, the possibility of sulfation of the plates will increase greatly.

2. ** Humidity and Corrosive Gases ** : If the humidity in the forklift operation environment is high, the battery casing may get damp, leading to a decline in the insulation performance of the casing, causing leakage, affecting the normal charging and discharging of the battery, and increasing the risk of sulfation of the plates. In addition, if there are corrosive gases in the working environment, such as sulfur dioxide and hydrogen sulfide, these gases will undergo chemical reactions with the battery casing and plates, corrode the plates, damage their structure, and promote the formation of lead sulfate crystals.

(3) Electrolyte Issues

1. Improper electrolyte density: Electrolyte density is one of the important factors affecting the performance of lead-acid batteries. If the density of the electrolyte is too high, it will increase the corrosive effect of sulfuric acid on the plates, accelerate the deterioration of the active substances on the plates, and also promote the formation of lead sulfate crystals. On the contrary, if the density of the electrolyte is too low, it will lead to a decrease in the discharge capacity of the battery, making it prone to over-discharge and subsequently causing sulfation of the plates. Lead-acid batteries of different models and specifications have specific requirements for the density of the electrolyte. If the electrolyte is not prepared in accordance with the standard, it will cause damage to the battery.

2. ** Low electrolyte level ** : During the use of the battery, the water in the electrolyte will gradually evaporate, causing the liquid level to drop. If distilled water is not replenished in time, the upper part of the plate will be exposed to the air and undergo an oxidation reaction with oxygen to form lead sulfate. Moreover, the exposed plate will accelerate sulfation during charging and discharging. In addition, if the electrolyte level is too low, it will cause local overheating of the plates, further aggravating the damage to the plates.

(4) Factors related to the battery itself

1. ** Plate Quality ** : The quality of the plates directly affects the performance and lifespan of the battery. Some low-quality plates have insufficient purity and structural stability of their active substances, and are more prone to sulfation during normal charging and discharging processes. For instance, if the impurity content in the plates is too high, it will affect the progress of electrochemical reactions, leading to abnormal growth of lead sulfate crystals.

2. ** Manufacturing process ** : The manufacturing process of the battery also has a certain impact on the sulfation of the plates. If there are defects in the coating process, curing process and other links of the plate during the manufacturing process, it will lead to the active material of the plate not bonding firmly with the substrate, and it is easy to fall off during charging and discharging, thereby affecting the normal performance of the plate and increasing the possibility of vulcanization.

4. Effective Measures to Prevent sulfation in the Maintenance of Forklift Lead-acid Battery Plates

(1) Optimize charging management

1. Establish a scientific charging system: Enterprises should formulate a reasonable charging plan based on the usage frequency, operation intensity of forklifts, and the specifications and models of batteries. Make sure the battery can be charged in time after each use and is fully charged to avoid undercharging. Generally speaking, when the remaining power of the battery is insufficient, it should be charged. The charging time should be reasonably arranged according to the capacity of the battery and the charging current, and it usually takes 8 to 10 hours. At the same time, overcharging should be avoided. Smart charging devices can be used, which can automatically detect the charging status of the battery and stop charging automatically when the battery is fully charged.

2. ** Adopt reasonable charging methods ** : In addition to the conventional constant current charging and constant voltage charging methods, advanced charging technologies such as pulse charging and desulfurization charging can also be adopted. Pulse charging can effectively eliminate sulfation of the plates, improve charging efficiency and extend the service life of the battery. Desulfation charging is aimed at batteries that have already shown slight sulfation. Through a specific charging procedure, lead sulfate crystals are reconverted into active substances. For newly purchased batteries, deep charging and discharging should be carried out before their first use to activate the active substances on the plates and improve the performance of the battery.

(2) Improve the usage environment

1. ** Temperature Control ** : In the cold winter, heating devices such as heating pads and insulation cotton can be installed in the forklift battery room to keep the battery's working temperature between 5℃ and 35℃, ensuring the fluidity of the electrolyte and the normal progress of electrochemical reactions. In the hot summer, it is necessary to pay attention to dissipating the heat of the battery and avoid direct sunlight. The forklift can be parked in a cool and well-ventilated place or a cooling fan can be installed to lower the temperature of the battery.

2. ** Moisture-proofing and Anti-corrosion ** : Keep the forklift's working environment dry. Regularly check if the battery casing is damp. If there is any dampness, dry it promptly. For forklifts operating in corrosive gas environments, ventilation equipment can be installed in the battery room to promptly expel harmful gases. At the same time, anti-corrosion paint can be applied to the surface of the battery casing to enhance its corrosion resistance. In addition, it is necessary to avoid direct contact of the battery with corrosive substances, such as acids, alkalis and other chemicals.

(3) Strengthen the management of electrolyte

1. ** Correct configuration of electrolyte ** : Prepare the electrolyte strictly in accordance with the requirements of the battery's user manual to ensure that the density of the electrolyte meets the standard. Under different seasons and usage environments, the density of the electrolyte can be appropriately adjusted. Generally, the density of the electrolyte can be slightly higher in winter and slightly lower in summer. When preparing the electrolyte, distilled water should first be poured into the container, then concentrated sulfuric acid should be slowly added while constantly stirring. Be careful not to our water into concentrated sulfuric acid to avoid danger.

2. ** Regular inspection and replenishment of electrolyte ** : Regularly check the height of the electrolyte level, usually once a week. If the level is found to be too low, distilled water should be replenished in time. When replenishing distilled water, use distilled water of higher purity and avoid using water containing impurities to prevent impurities from entering the battery and affecting its performance. At the same time, be careful not to spill the electrolyte on the battery case or the ground. If it does spill, clean it up in time.

(4) Daily Maintenance and Inspection

1. ** Visual Inspection ** : Conduct a daily visual inspection of the battery to check if the casing is damaged, deformed, or leaking, and to inspect if the terminals are loose or oxidized. If the casing is found to be damaged or leaking, the battery should be replaced in time. If the terminal post is loose, the fixing bolts should be tightened. For oxidized terminal posts, they can be sanded clean with sandpaper and coated with Vaseline or a special terminal post protector to prevent further oxidation.

2. ** Performance Testing ** : Regularly test the performance of the battery. A dedicated battery tester can be used to measure parameters such as voltage, internal resistance, and capacity of the battery. The health condition of the battery can be judged by the detection data, and potential problems can be discovered in a timely manner. Generally, a performance test should be conducted once a month. For batteries that have been in use for a long time or have experienced significant performance decline, the testing frequency should be increased. If sulfation is found in the battery, corresponding repair measures can be taken according to the degree of sulfation, such as using de-sulfation charging and adding repair agents.

(5) Use the battery reasonably

1. ** Avoid over-discharge ** : During forklift operation, pay close attention to the battery power display to prevent over-discharge. When the battery indicator light shows low battery level, the operation should be stopped in time and the forklift should be driven back to the charging area for charging. Excessive discharge will cause a large amount of lead sulfate to be generated on the plates, accelerating the sulfation of the plates. In addition, when starting the forklift, do not start it frequently. The interval between each start should be more than 10 seconds to avoid damage to the battery caused by large current discharge.

2. ** Balanced Use of batteries ** : For forklifts with multiple sets of batteries used alternately, it is necessary to pay attention to balanced use to avoid overusing one set of batteries while leaving the others idle for a long time. A reasonable usage plan can be formulated, and the batteries can be rotated regularly to ensure that the charge and discharge cycles of each group of batteries are approximately the same, thereby extending the overall service life of the batteries.

5. Conclusion

Sulfation of the plates of forklift lead-acid batteries is a complex issue influenced by multiple factors, seriously threatening the performance and service life of the batteries. By thoroughly understanding the principle and hazards of plate sulfation, comprehensively analyzing the factors leading to sulfation, and adopting a series of effective maintenance measures such as optimizing charging management, improving the usage environment, strengthening electrolyte management, daily maintenance and inspection, and rational use of batteries, the risk of plate sulfation can be significantly reduced, the service life of batteries can be prolonged, and the operational efficiency of forklifts can be improved. Reduce the operating costs of enterprises. In practical applications, enterprises should attach great importance to the maintenance of lead-acid batteries in forklifts. They should formulate scientific and reasonable maintenance plans based on their own actual conditions and strictly implement them to ensure that the lead-acid batteries of forklifts are always in good working condition, providing reliable power support for the production and operation activities of the enterprises. Meanwhile, with the continuous development of technology, new battery maintenance technologies and products are constantly emerging. Enterprises should keep abreast of industry trends in a timely manner, actively adopt advanced technologies and methods, and further enhance the maintenance level of batteries.