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1. Introduction

In the modern logistics warehousing and industrial production fields, forklifts have become indispensable equipment due to their efficient cargo handling capabilities. As the core power source of forklifts, the performance stability of lead-acid batteries in forklifts is directly related to the operational efficiency and safety of forklifts. However, in actual use, lead-acid batteries often experience leakage problems. This not only leads to a decrease in battery capacity and shortens the battery's service life, but also may corrode forklift components and even cause safety accidents. Therefore, having a thorough understanding of the leakage problem of lead-acid batteries in forklifts and mastering scientific and effective detection and solution methods is crucial for ensuring

The normal operation of forklifts is of great significance.

2. Basic Working Principle of Lead-Acid Batteries

Lead-acid batteries are a type of chemical power source that uses lead and its oxides as electrode materials and sulfuric acid solution as the electrolyte. Its charging and discharging process is based on REDOX reactions. During charging, electrical energy is converted into chemical energy and stored in the battery. The spongy lead at the negative electrode is oxidized to lead sulfate, and the lead dioxide at the positive electrode is reduced to lead sulfate. During discharge, chemical energy is converted into electrical energy. The lead sulfate at the negative electrode is reduced to spongy lead, and the lead sulfate at the positive electrode is oxidized to lead dioxide. This chemical reaction process requires the electrolyte to conduct ions between the electrodes to maintain the progress of the electrochemical reaction. However, once leakage occurs, it will disrupt this balance and affect the performance of the battery.

3. Analysis of Common Causes of Leakage

(1) The shell is damaged

Mechanical damage: During daily operations, forklifts often encounter complex working environments, such as narrow passageways and bumpy ground. When a battery is subjected to collision or compression, its casing may develop cracks or damage, leading to electrolyte leakage. For instance, during the process of goods handling, the forklift collides with the shelves, and the battery casing is hit by the corners of the shelves, forming tiny cracks. At first, these cracks may not be easily detectable, but as the usage time increases, the cracks gradually expand, eventually leading to leakage.

Aging and cracking: The casing of lead-acid batteries is usually made of plastic. When used for a long time in high-temperature and humid environments, the casing material will gradually age and its toughness will decline, thus leading to cracking. Especially during the high-temperature period of summer, the internal temperature of the battery rises, the pressure on the casing increases, and the risk of aging and cracking also rises accordingly.

(2) Poor sealing

Terminal post seal failure: The terminal post is an important component that connects the internal and external circuits of the battery, and its sealing performance is of vital importance. During the production process, if the sealant between the terminal post and the housing is not applied evenly, the quality of the sealant is poor, or the sealant ages and falls off due to high temperature, vibration and other reasons during use, it will lead to the failure of the seal at the terminal post, and the electrolyte will seep out from the gap between the terminal post and the housing. The cover is not tightly sealed: The battery cover and the casing are sealed with sealant or gasket. If the sealant is not applied sufficiently, the gasket is not installed properly, or the gasket ages or deforms, the sealing effect between the cover and the shell will deteriorate, and the electrolyte is prone to leak out from the gap.

(3) Overcharging and overdischarging

Overcharging: When a lead-acid battery is overcharged, intense chemical reactions occur inside the battery, generating a large amount of gas. These gases accumulate inside the battery, which will cause the internal pressure of the battery to rise sharply. When the pressure exceeds the load-bearing capacity of the battery casing and sealing components, it will cause the battery casing to swell and deform, damage the sealing components, and subsequently lead to leakage.

Over-discharge: Over-discharge will cause a large amount of active substances on the battery plates to be consumed, leading to sulfation of the plates. After vulcanization, the volume of the plates increases, which will squeeze the internal space of the battery, damage the sealing structure of the battery, and cause leakage of the electrolyte. At the same time, over-discharge will also cause changes in the concentration of the electrolyte inside the battery, accelerate the corrosion of the internal components of the battery, and further increase the risk of leakage.

(4) Improper addition of electrolyte

Excessive addition of electrolyte: When maintaining lead-acid batteries, if the amount of electrolyte added exceeds the specified upper limit, when the battery is charging or the temperature rises during operation, the electrolyte expands and will overflow from the battery's exhaust holes or poorly sealed areas, causing leakage.

Electrolyte quality issues: Using electrolyte of substandard quality, which may contain impurities or have component ratios that do not meet the requirements. These impurities can undergo chemical reactions inside the battery, generating gas or corroding the internal components of the battery, causing changes in the internal pressure of the battery and damage to the sealing parts, thereby triggering leakage.

4. Methods for Troubleshooting Leakage Issues

(1) Visual inspection

Check the casing: Carefully observe the surface of the battery casing to see if there are any cracks, damages, bulges or other phenomena. For minor cracks, you can use a flashlight or other light sources to observe from different angles to ensure that no possible damage is missed. At the same time, check if there are any traces of electrolyte residue on the surface of the casing. If white crystals or damp marks are found at the bottom or side of the casing, it is very likely to be caused by leakage.

Check the terminal post and cover: Observe whether there are signs of electrolyte leakage around the terminal post and whether there are white or green corrosion substances on the surface of the terminal post. Check the connection between the cover and the shell, and observe whether the sealant or gasket is intact, and whether there are any gaps or traces of electrolyte leakage.

(2) Stress test

Use professional battery pressure testing equipment to conduct pressure tests on the storage batteries. Connect the test equipment to the exhaust hole of the battery, slowly apply a certain pressure inside the battery (the pressure value should be within the allowable range of the battery), and then observe the change in pressure. If the pressure drops rapidly, it indicates that the battery has a poor seal problem and there may be a leakage point. By this method, the sealing performance of the battery can be judged relatively accurately. However, it should be noted that the pressure test operation should be carried out with caution to avoid damage to the battery due to excessive pressure.

(3) Charge and discharge tests

Conduct charge and discharge tests on the battery and closely observe its working condition during the charging and discharging process. During the charging process, pay attention to whether there is any abnormal gas inside the battery that makes a sound, and whether the battery casing gets hot or swollen. During the discharge process, monitor the voltage changes of the battery. If the voltage drops abnormally fast, it may be due to leakage causing a reduction in battery capacity. At the same time, after the charging and discharging are completed, conduct another visual inspection of the battery to see if there are any new signs of leakage.

(4) Electrolyte testing

Draw a small amount of the electrolyte inside the battery and test its density and composition. Under normal circumstances, the density of the electrolyte in lead-acid batteries should fall within the prescribed standard range. If the detection reveals that the density of the electrolyte is abnormally low or it contains impurities, it indicates that there may be a problem with the electrolyte, and further inspection is needed to determine whether the leakage is caused by the electrolyte issue. In addition, the pH level of the electrolyte can be detected to determine whether the chemical reactions inside the battery are normal and whether there is any leakage caused by abnormal chemical reactions.

5. Solutions to Leakage Problems

(1) Shell repair and replacement

Minor crack repair: For minor cracks on the shell, plastic welding can be used for repair. First, clean the plastic surface around the crack thoroughly to remove dust, oil stains and other impurities. Then, using plastic welding rods of the same material as the shell, the cracks are welded and repaired through plastic welding equipment. After the welding is completed, the repaired area should be ground to make its surface smooth and flat, and the repair effect should be checked to ensure that the cracks are completely sealed.

Severe damage replacement: When the battery casing shows severe damage, swelling or deformation, etc., a new battery casing should be replaced in a timely manner. When replacing the casing, choose a casing that matches the model and specification of the primary battery to ensure proper installation. During the replacement process, operate carefully to avoid damaging the internal plates and other components of the battery. At the same time, after replacing the casing, the battery should be resealed to ensure good sealing performance.

(2) Sealing treatment

Terminal post seal repair: If the terminal post seal fails, it needs to be resealed. First, clean the old sealant around the terminal post thoroughly. Then, use sandpaper to polish the surface of the terminal post to make it rough, which will enhance the adhesion of the sealant. Then, apply an appropriate amount of high-quality sealant and evenly spread it at the connection between the terminal post and the casing, ensuring that the sealant fully fills the gaps. After the application is completed, wait for the sealant to cure. During the curing process, avoid the battery being affected by vibration or external force.

Lid sealing improvement: For cases where the lid is not sealed tightly, it is necessary to check the condition of the sealant or gasket. If the sealant ages or becomes ineffective, the old sealant should be cleaned up thoroughly and new sealant should be reapplied. If the gasket is damaged or deformed, a new gasket should be replaced in time. When installing the cover, make sure that the cover is aligned with the shell, the screws are tightened evenly, and a good sealing effect is guaranteed.

(3) Standardize charging and discharging operations

Reasonable control of charging time and current: When charging lead-acid batteries, strictly follow the requirements of the battery's user manual, select the appropriate charger, and set the charging time and current reasonably. Avoid overcharging. Generally, when the battery is fully charged, charging should be stopped in time. At the same time, during the charging process, closely monitor the temperature and voltage changes of the battery. When it is found that the battery temperature is too high or the voltage is abnormal, stop charging immediately and check if there is any problem with the battery.

Prevent excessive discharge: During the operation of forklifts, it is necessary to pay attention to monitoring the remaining battery power to avoid excessive discharge of the battery. A battery power display device can be installed on the forklift to show the battery power in real time. When the battery power is lower than the specified lower limit value, the battery should be charged in time. In addition, during the battery discharge process, it is necessary to avoid long-term high-current discharge to prevent sulfation of the battery plates, which may affect the battery's performance and service life.

(4) Add the electrolyte correctly

Control the amount of electrolyte added: When adding electrolyte, strictly follow the requirements of the battery's user manual and add the electrolyte to the specified liquid level scale range. A dedicated electrolyte filling tool can be used to accurately control the amount of electrolyte added. After adding the electrolyte, the residual electrolyte on the battery surface should be cleaned up in time to prevent the electrolyte from corroding the battery casing and other components.

Select high-quality electrolyte: When purchasing electrolyte, choose products of qualified quality produced by regular manufacturers to ensure that the composition of the electrolyte meets the standard requirements. Avoid using electrolytes containing impurities or of substandard quality to prevent battery leakage and other malfunctions caused by electrolyte issues. At the same time, when adding the electrolyte, it is necessary to keep the electrolyte clean to avoid bringing impurities into the battery interior.

6. Preventive Measures

(1) Strengthen daily maintenance and upkeep

Regularly conduct appearance inspections, electrolyte tests and charge and discharge tests on the lead-acid batteries of forklifts to promptly identify and address potential issues. Keep the battery surface clean and dry. Regularly clean the dust, oil stains and corrosive substances on the battery casing and terminals to prevent damage to the sealing components due to corrosion. At the same time, it is necessary to regularly check the connection lines of the battery to ensure a firm connection and avoid battery failure caused by loose lines.

(2) Standardize operation and use

Operators must strictly follow the operating procedures of the forklift to avoid damaging the battery due to improper operation. When handling goods, be careful to avoid the forklift colliding with other objects to prevent mechanical damage to the battery. At the same time, the working hours of the forklift should be reasonably arranged to prevent the battery from working continuously for a long time. Appropriate rest time should be given to the battery to extend its service life.

(3) Improve the working environment

Try to provide a good working environment for the lead-acid batteries of forklifts and avoid the batteries being in harsh environments such as high temperatures, humidity and corrosive gases for a long time. Ventilation equipment can be installed in the battery storage area to reduce the environmental humidity and temperature, and to decrease the risk of battery casing aging and sealing component damage. At the same time, it is necessary to prevent the battery from coming into contact with corrosive substances to avoid electrolyte leakage and corrosion of the internal components of the battery.

7. Conclusion

Leakage of lead-acid batteries in forklifts is a common fault that affects the normal operation of forklifts and the service life of the batteries. By thoroughly understanding the working principle of lead-acid batteries, comprehensively analyzing the causes of leakage problems, mastering scientific and effective inspection methods and solutions, and taking active preventive measures, the leakage problem of lead-acid batteries can be effectively solved, ensuring the safe and efficient operation of forklifts. In practical work, enterprises and operators should attach great importance to the maintenance and correct use of lead-acid batteries, constantly improve the management level of batteries, extend the service life of batteries, reduce equipment maintenance costs, and create greater value for the production and operation of enterprises.