The main reason for shortening the service life of base station batteries
First, the role of the battery pack in the communication system
At present, most of the batteries used in communication power are advanced valve-regulated sealed lead-acid batteries. The voltage of each cell of this battery is generally 2V, which forms a 48V or 24V system in series. It protects communication equipment and facilities Two functions to ensure the smooth operation of the network. In ensuring communication power equipment facilities, the battery, together with the UPS and switching power supply system, plays a role in preventing voltage surges, waves, spikes (drops), transients, and undervoltages (overvoltages) in the utility grid, which effectively protects communication equipment, Prevent downtime accidents. In ensuring the smooth operation of the network, the battery, UPS, and switching power supply system work together to maintain the normal operation of the system when the mains power is interrupted, while also filtering out noise voltages and maintaining communication quality.
Once these batteries are installed and put into operation in a communication base station, they will not be replaced within a few years. Therefore, it is of great significance to strengthen the maintenance of the battery and improve its use, thereby effectively extending the service life of the battery. The battery online detection is currently unattended and plays an indispensable role in the maintenance of communication power.
Second, the technical status of the communication system battery
The base station to achieve battery current is not an important part of the uninterruptible power supply, and its investment switching power supply device is roughly equal. At present, most mobile base stations use valve-regulated sealed lead-acid batteries ( VRLA batteries) developed at the end of the twentieth century. Due to the use of a valve-controlled sealing structure, no acid or water maintenance is required, no acid liquid or acid mist leaks out, and it can be installed in the same equipment room as the equipment. Because of its small size, lightweight, small self-discharge, less maintenance, long life, easy to use, safe and reliable, it is welcomed by users. However, we must see that on the one hand, the basic electrochemical principle of this battery has not changed, so its inherent electrical characteristics requirements have not only remained unchanged but have become more stringent; on the other hand, in the early stage of this battery's promotion, manufacturers' instructions Sometimes this battery is more or less called a "maintenance-free" battery, causing some maintenance personnel to think that this battery does not require maintenance, which makes battery maintenance and testing not given due attention. This misleading has so far Have a profound impact.
From the current use situation of base station batteries, it is common for battery capacity to drop too quickly, with short service life, and frequent drop-out accidents. In terms of the quality of the batteries produced by several large valve-regulated sealed battery manufacturers in China, they should be able to meet the requirements of various operators, although the quality and performance of the batteries produced by each manufacturer are different. The quality factor of the battery should not be the main reason that affects the battery capacity of base stations of various operators and the service life has been reduced too quickly. From the comprehensive factors of valve-regulated sealed battery product structure, product performance, and site survey of the use of base station batteries, combined with the use of exchange stations, the capacity of valve-regulated sealed batteries after 1 to 4 years of normal use, its capacity decline should not be so fast, causing the base station battery capacity drops too fast, shorten the life of the main reason for its base station should use the environment as well as related maintenance.
The main reasons that cause the battery capacity of base stations to fall too quickly and shorten the service life are:
First, the base station has frequent power outages, long power outages, and irregular power outage times, which frequently causes the battery to charge and discharge. According to the current battery manufacturer's anatomy of the battery at the base station, the end of battery life is caused by the sulfate of the battery negative plate This is a typical phenomenon of early battery capacity failure ( PCL).
The reason for causing the sulfate of the negative plate of the battery is as follows: the frequency of power outages in the base station is too high, and there are several times of power outages in a day, or even several days of continuous power outages so that the battery of the base station is discharged without being fully charged after discharge, and the battery is undercharged. If multiple undercharges occur consecutively, which will cause a cumulative loss of battery capacity, the battery capacity of the base station will decrease in a short period, and its service life will be terminated quickly. Generally speaking, the speed at which the battery capacity decreases is proportional to the number of consecutive undercharges of the base station battery. The internal cause of the decrease in battery capacity is that when the battery is discharged after it is not fully charged, the lead sulfate produced by the positive and negative electrodes after discharge can not be fully restored to lead dioxide and metal lead, respectively. The negative plate is discharged again, causing the battery to be undercharged. The battery is undercharged several times in a row, which gradually sulfates the negative plate and produces irreversible crystalline lead sulfate, especially when the battery is under over-discharge. The change will be more serious, and the speed of sulfation will be faster, which will cause the surface of the negative plate to be shielded, and its function will gradually decrease until it fails, which will lead to the decline of the battery life until the termination.
Second, the setting parameters of the switching power supply are unreasonable. The base station battery undervoltage protection setting voltage is too low and the reset voltage is set too low, which causes the battery to over-discharge or even deep over-discharge, which exacerbates the sulfation of the battery negative plate.
At present, the base station combination switching power supply is provided with a low-voltage isolation protection function or a secondary power-off function. When the battery is discharged to a set voltage value, the switching power supply system automatically cuts off the power supply to the load or part of a heavy load of all, to protect the battery is not over-discharged, to ensure that the battery life.
If the battery's minimum undervoltage protection value is set too low, the battery will be over-discharged. Multiple over-discharges and failure to recharge in time or under-charge after over-discharge will seriously affect the battery life; besides, if the reset voltage of the switching power supply is set too Low, it will make the battery repeatedly discharge many times during the discharge process; the specific battery minimum undervoltage protection value should be set according to the load current, and the current base station battery minimum undervoltage protection value is generally set at 1.8 per cell voltage Around V, some even set to 1.75V each. According to the discharge performance of the valve-regulated sealed battery combined with the actual load current of the base station (most of the actual load current of the base station is currently less than 0.1C10A), the minimum undervoltage protection value of the base station battery should be set above 1.8V per cell voltage.
Therefore, the current base station battery undervoltage protection reference voltage is set too low, such as group owners time power failure, the battery will discharge occurred, even a small current depth of discharge, and over-discharge of the battery to be fully charged, the charge capacity required to recover For a long time and deep over-discharged batteries, it is generally difficult to fully recover their rated capacity under the condition of the base station's only constant voltage charging. Therefore, the setting of the parameters of the switching power supply is unreasonable, and on the other hand, the sulfation of the battery negative plate is exacerbated, which causes the battery capacity to decrease and the service life to be shortened.
Third, the use environment of base stations is poor. After the base station is powered off, the ambient temperature of the base station gradually rises because there is no air conditioning. Or due to air conditioning failure, the indoor temperature of the base station is high, thereby reducing battery life.
The indoor base stations are all equipped with air conditioners. The air conditioners configured are general cabinets or split air conditioners. Long-term uninterrupted use will cause some base stations to fail and shut down the air conditioners. Sometimes the air conditioners are not repaired in time when they are damaged. After the shutdown, the indoor temperature of the base station rises sharply, and the indoor temperature of the color steel equipment room can even reach above 70 ° C.
On the one hand, even if the air conditioner is normal, and the base station cannot be cooled due to the absence of AC power after the power failure, especially in the summer, the indoor temperature of the base station will rise significantly, which will affect the normal operation of the battery. This makes the internal water loss of the valve-regulated sealed battery worse, and the electrolyte saturation decreases (the electrolyte in the glass fiber wool membrane decreases), which reduces the battery capacity and shortens the battery life.
On the other hand, because the indoor temperature is too high, the thermal runaway effect of the battery will be exacerbated, which will cause the battery positive plate corrosion rate to increase, the electrode plate to deform and expand, the battery case to swell and even crack, etc., which will eventually lead to a rapid decline in battery capacity and shorten battery life. According to the accelerated life test, if the ambient temperature is increased by 10 degrees and the charging voltage is not adjusted, the battery life will be reduced by half.
Fourth, after the base station is powered off, the battery is discharged to the termination voltage and failure to replenish power promptly will also lead to a decrease in battery capacity and a shortened service life.
Because some base stations are located in the suburbs or remote mountain villages, etc., the power supply situation is poor, the number of power outages is long and the power outage is long. Often, once the power outage occurs, the battery discharges to the termination voltage, and the city power has not recovered. On the one hand, this may cause the battery to over-discharge, and on the other hand, the battery cannot be recharged in time. According to relevant data, if the battery cannot be recharged in time after discharge, the battery capacity will gradually decrease. After several cycles, Battery life will be significantly reduced.
In other base stations, the switching power supply output floating charge voltage value is more than 1V smaller than the set value and display value, which causes the battery to be undercharged for a long time.
Despite these problems with the batteries used in communication stations, the maintenance systems and equipment of our main telecommunications operators cannot guarantee timely detection of battery problems, timely maintenance of them, and timely replacement of backward batteries. , To avoid the occurrence of drop-off accidents. The battery on-line monitoring system came into being under such circumstances.
Third, the battery monitor must be of
From the above analysis, communication power is the foundation of the communication network, and the backup battery is the last barrier of the entire communication power. Once the accident caused by the battery, especially the battery in the communication room, will cause huge losses! Therefore, to ensure the smooth operation of the communication network, various communication operators have intensified the maintenance and testing of the battery in the communication room, while introducing strict maintenance regulations of IEEE1189-2005. The current maintenance regulations mainly rely on regular, mandatory check discharges to monitor the health and charging status of batteries. However, due to the limitation of the establishment of maintenance technicians, the remote and scattered maintenance sites, and the long time required for inspection operations, the completion rate of battery maintenance in the entire communications industry is very low. At present, the only feasible maintenance technique without testing dead zones is the use of battery monitoring systems. Battery monitoring has the following advantages over traditional regular monitoring;
Reduce the manual time required to manually measure and check the battery on site.
The data provided by the monitoring system can be used to understand the health status of the battery in a planned way without the need to check on-site according to the calendar, thereby saving costs.
Continuous online battery system monitoring improves the reliability of power supply and reduces system downtime.
Replace the impending battery before it affects other batteries in the same group to avoid mutual influence, thereby extending the overall battery system life.
Know which batteries have reached the replacement time, so that you have more initiative in battery procurement while reducing the occurrence of batch replacement batteries.
Increase customer satisfaction and uptime by reducing the chance of power outages.
Avoid loss of annual income due to power outages.
The ability of the monitoring system to identify batteries with signs of damage increases system reliability, which in turn increases production capacity.
With our patented impedance measurement technology, reliable trend data will accurately show battery problems when the battery begins to fail.
Do not rely on measuring the voltage to determine the battery status, the voltage measurement cannot accurately show the quality and availability of the battery.
The battery monitoring management system has the functions of remote monitoring, data collection, and trend analysis. It can remotely monitor multiple battery systems, which improves management efficiency.
It can be foreseen when and where the power company will lose power because the battery system cannot provide a DC power supply.
Accurately track and record battery real-time performance during power outages.
Accurately monitor all items that have a direct impact on battery performance:
Although the installation of the battery and a one-time online system will increase the operation and maintenance costs expenses, but the charge to improve the battery life has 30%, reduce maintenance workload 75%, 80% reduction in maintenance costs, reduce out station accident occurred, improve customer communication Looking at the return of satisfaction, it is worth it.