Use and maintenance of VR batteries Abstract: This paper introduces the principle of valve-controlled battery , analyzes the main factors affecting the service life of the battery, and puts forward the methods and precautions for the correct use and maintenance of the battery. Keywords: battery; use; maintenance Use and Maintenance of Valve Regulated Lead? acid Battery(VRLAB) ZHANG Xi- feng, LIU Jun- shan, LI Jian- ling, DONG Qing- yun Abstract:The principle of VRLAB is introduced. The main causes to influence the lifetime of VRLAB are analyzed. The correct methods to use and maintain VRLAB and matters concerned are described. Keywords:Battery; Use; Maintenance 1 Introduction As an independent operating power source, the battery has the advantages of high reliability, so it is widely used in substations and power plants. The earliest used ordinary lead-acid battery has low overload capacity and is prone to acid corrosion. After the 1980s, it was gradually replaced by cadmium-nickel battery, although it has high reliability, small volume, small pressure drop, strong overcharge resistance, and discharge. The voltage is stable, the discharge rate is high, and the life is long. However, there are also disadvantages such as low battery voltage, large number of uses, relatively large maintenance workload, and cumbersome operation. The valve-controlled battery has explosion-proof safety, low usage, and battery bill. High body voltage and easy maintenance. At present, due to the replacement of charging equipment, especially the application of high-frequency switching power supply, the valve-controlled battery with strict requirements (regulation, steady current, ripple coefficient, etc.) has been widely used. The valve-regulated battery mainly has two types: lean liquid type and glue type. Because the valve-controlled battery is fully sealed and does not require water maintenance, it is often referred to as “maintenance-freeâ€. The term “maintenance-free†brings a misunderstanding to the user, causing the user to relax the routine maintenance and management of the valve-controlled battery. Therefore, the correct use and maintenance of valve-regulated batteries is of great significance. 2 valve-controlled battery principle The valve-controlled battery will be electrolyzed during charging and at the end of charging. Under normal circumstances, oxygen is present in the positive electrode and hydrogen is present in the negative electrode. Since the battery adopts a maintenance-free plate, the potential of the hydrogen is increased, and the reaction zone and the reaction speed are different, so that the oxygen of the positive electrode appears before the negative electrode, and the reaction of the positive electrode is as follows: 2H2O→O2+4H++4e- Oxygen reacts chemically through the separator channel or the top to the negative electrode. Pb+O2+2H2SO4→PbSO4+H2O The negative electrode is oxidized to lead sulfate, which is converted into sponge-like lead after charging. PbSO4+2e-+H+→Pb+HSO4- Due to the structure of the valve-controlled battery, a certain pressure and gas are reserved inside the battery to ensure the above reaction cycle, and at the same time, the precipitation of the negative hydrogen gas is suppressed, and the water consumption in the battery is controlled, so that the battery can be sealed and operated. 3 Main factors affecting the service life of valve-controlled batteries The normal service life of valve-controlled battery full float is more than 10 years, theoretically up to 20 years, but in actual use, there are many factors affecting the service life of valve-controlled batteries, mainly 1) Ambient temperature Excessive ambient temperatures have a significant impact on battery life. When the temperature rises, the plate corrosion of the battery will increase, and more water will be consumed, thereby shortening the battery life. The battery can be used for a long life at 25 ° C. If the long-term operating temperature is increased by 10 ° C, the service life is reduced by about half. 2) Overcharge In the long-term over-charge state, the positive electrode is depleted due to oxygen evolution, water is consumed, and H+ is increased, resulting in an increase in acidity near the positive electrode, accelerated corrosion of the grid, thinning of the grid, accelerated corrosion of the battery, and reduced battery capacity; Intensification will cause the battery to dry up, which will affect the battery life. 3) Over discharge Over-discharge of the battery mainly occurs after the AC power supply is cut off, and the battery supplies power to the load for a long time. When the battery is over-discharged to a voltage that is too low or even zero, a large amount of lead sulfate inside the battery is adsorbed to the cathode surface of the battery, causing "sulfation" at the cathode of the battery. Lead sulfate is an insulator, and its formation will have a great negative impact on the charge and discharge performance of the battery. Therefore, the more sulfate formed on the cathode, the greater the internal resistance of the battery, the charge and discharge performance of the battery. The worse, the shorter the battery life. 4) Long-term floating charge In the long-term floating state of the battery, the battery is only charged and not discharged, which will inevitably cause the anode plate of the battery to be passivated, so that the internal resistance of the battery increases, and the capacity is greatly reduced, thereby shortening the service life of the battery. 4 Proper use and maintenance of VR batteries The following are the issues that should be noted during the use and maintenance of VR batteries. ——The battery should be placed in a place that is ventilated, dry, away from heat sources and not prone to sparks. The safety distance is 0.5m or more. In the ambient temperature of 25 ° C ~ 0 ° C, the discharge capacity drops by about 1% for every 1 ° C drop, so the battery should work in the environment of 15 ° C ~ 20 ° C. ——To make the battery have a long service life, please use a good performance automatic voltage limiting current charging device. When the load changes within the normal range, the charging device should achieve ±2% voltage regulation accuracy to meet the requirements specified in the battery specification. Do not stop the float when the battery used for float charging is not in operation. ——The charging law of constant current limiting voltage charging → constant voltage charging → floating charging after recharging must be strictly observed. It is best to use high frequency switching power supply type charging device to allow intelligent management of the battery at any time. . ——A newly installed or overhauled VRLA battery pack shall be subjected to a full-respective discharge test. After that, a check-up discharge test shall be carried out every 2 to 3 years, and a valve-controlled battery that has been operated for 6 years shall be checked once a year. Sex discharge experiment. If the battery pack capacity fails to reach more than 80% of the rated capacity after 3 times of recharge charging, it can be considered that the life of this group of valve-controlled batteries is terminated and should be replaced. ——When maintaining the measuring battery, the operator's face shall not face the top of the battery and should maintain a certain angle or distance. —— During the operation of the battery, the connecting wires should be inspected once every six months. The bolts are loose or corroded. The loose bolts must be tightened in time (the torque of the bolts and nuts is about 11N·m), and the corroded and contaminated joints should be cleaned in time. During the charging and discharging process of the battery pack, if the connecting strip generates heat or the pressure drop is greater than 10 mV, the contact part of the connecting strip should be sanded in time with sandpaper or the like. ——Do not use different manufacturers, different models, different types, different capacities, different performances, and different old and new battery strings. ——Configure online monitoring and management technology for the battery, conduct on-line monitoring of the battery at any time, understand and grasp the voltage and pressure difference of the battery (see Table 1), etc., in order to find the defects of the battery in time and carry out maintenance in time. —— During normal operation of the battery, the battery voltage and ambient temperature should be measured once a week; the battery voltage and ambient temperature should be measured once a month, and the recording should be made; the open circuit voltage (cell voltage) should be checked every quarter; A capacity check (discharge current is 0.1C10A, the termination voltage meets the requirements in Table 1), and record; the complete battery history (including the date of manufacture, installation date, operation, etc.) should be maintained. Table 1 Specification of voltage deviation value and discharge termination voltage value of valve-regulated battery during operation Valve controlled battery standard voltage 2612 The maximum deviation of voltage during operation is ±0.05±0.15±0.3 Open circuit voltage maximum and minimum voltage difference 0.030.040.06 The discharge termination voltage value is 1.805.40 (1.80×3) 10.80 (1.80×6) Machining Plastic has a small density, light weight, can be insulated. machining Plastic is the use of CNC machining out, including drilling. Cutting, turning, machining Plastic commonly used products are: PA PC, Tetlon POM, PMMA. , we have a special inspection room to test the products, to ensure that and each size in line with the requirements of the drawings, but also a special machine for the production of material to withstand voltage insulation test. Applied in a variety of industries, including: drone, ship, communications, medical equipment, industrial automation equipment. 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