The battery pack is an important part of the base station to achieve DC uninterrupted power supply, and its investment amount is basically the same as that of the rack power supply. At present, the mobile base station adopts a valve-regulated sealed lead-acid battery (referred to as VRLA battery) developed at the end of the 20th century. Due to the valve-regulated sealing structure, it is not necessary to add acid and water to maintain, no acid liquid and acid mist are discharged, and it can be placed in the same room as the equipment. Because of its small size, light weight, small self-discharge, low maintenance, long life, easy to use, safe and reliable, it is well received by users. But we must see that on the one hand, the basic electrochemical principle of this battery has not changed, so its inherent electrical characteristics are not only unchanged, but more demanding; on the other hand, the battery is in the early stage of promotion, the manufacturer's instructions Sometimes such batteries are referred to as "maintenance-free" batteries, and some maintenance personnel believe that such batteries do not require maintenance. This misunderstanding still affects. Therefore, it is still very important to scientifically strengthen the maintenance and maintenance of such battery packs to improve their availability.
One is to prevent overcharging. The life and performance of the battery are closely related to the heat accumulation inside the battery. The heat source inside the battery is mainly due to the power loss of the internal electrochemical reaction. It can simply look at the product of the charging voltage and the charging current. In the oxygen recombination reaction, the float charge flow is increased to generate more heat, and during constant voltage charging, the float charge flow increases with temperature, thereby further increasing the temperature. The thermal runaway phenomenon is a peculiar phenomenon caused by the structure of the valve-controlled sealed battery. Thermal runaway often causes serious damage such as battery water loss, shell 'bulk belly', etc., and serious battery waste. To prevent overcharging, it is necessary to provide the charging voltage value strictly according to the manufacturer's instructions. Now the combined power supply can be set and intelligent management. It is necessary to pay attention to the first step, and the unauthorized personnel can not change it.
The second is to prevent insufficient charging. Contrary to overcharging, the lack of charging is mainly caused by the charging voltage setting being too low or too low. Or there is a problem with the rack system.
The third is to prevent over-discharge. The depth of discharge is closely related to the number of charge and discharge cycles (lifetime) of the battery design. For example, when the depth of discharge is 5%, the number of cycles is 10 000, and when the depth of discharge is 50%, the number of cycles is only 800. Excessive discharge will cause the battery to no longer be activated to the best state, or even scrapped. The discharge time and the termination voltage are different at different discharge rates, and the effective capacity released is also different and is affected by the ambient temperature. The relevant curves are no longer listed and drawn here, as given in the battery specifications of different manufacturers. Maintenance personnel should pay attention to it and set it in the monitoring unit strictly according to the relevant data, and should not be changed at will. Now the rack power supply manufacturer is designed with a battery power-off function, that is, when the battery is discharged to the set termination voltage, the battery discharge circuit is automatically cut off by the monitoring command. Some manufacturers have considered that the monitoring unit can not detect the battery termination voltage due to its operation (depending on its working power supply) or the device can forcibly cut off the circuit when the command cannot be issued. Therefore, maintenance personnel should pay attention to the reliability of these hardware circuits during inspection and inspection.
The fourth is to control the ambient temperature. When the battery temperature rises, the electrolyte activity is intensified, the internal resistance of the battery is reduced, and the floating charge flow is increased, which causes the corrosion of the conductive element to be intensified and the life is reduced. Conversely, the electrolyte activity is weakened, the internal resistance of the battery is increased, and the discharge of the battery to the load is performed. The ability is weakened. Therefore, it is necessary to monitor the battery temperature and control and maintain the ambient temperature. At the same time, the charging voltage must be temperature compensated to avoid overcharging at high temperatures and undercharging at low temperatures. In most places where VRLA battery packs are used, the ambient temperature is controlled at about 25 degrees. Accelerated life tests show that the ambient temperature rises by 10 degrees, and the charging voltage is not adjusted, and the battery life will be shortened by half.
The fifth is to replace the faulty battery in time. Due to the process variation of each monomer, the long-term floating charge may gradually become 'backward', so there will be a management function of regularly charging the battery pack in the monitoring unit, in order to activate this backward monomer, so that it does not Behind. But often behind, it may eventually become a faulty battery. We can use a variety of methods to determine whether it has become ill, such as its capacity test alone, or online testing its internal resistance. The key is to replace the faulty battery in time, which is very important for the availability of the battery pack and even the entire life of the battery pack.
