First, the role of battery packs in the communication system Most of the batteries used in current communication power supply are advanced valve-regulated sealed lead-acid batteries. The voltage of each cell of this battery is generally 2V, and the 48V or 24V system is composed in series. It plays two major functions of protecting communication facilities and ensuring the smooth operation of the network. In the protection of communication power equipment and facilities, the battery and the UPS and the switching power supply system work together to prevent voltage surges, waves, spikes (drops), transients, and undervoltages (overvoltages) in utility power networks, effectively protecting communications equipment, Prevent accidents at the station. In ensuring the smooth operation of the network, the battery and the UPS and the switching power supply system function together to maintain the normal operation of the system when the mains power supply is interrupted, and at the same time, it also functions to filter out the noise voltage and maintain the communication quality.
Once these batteries are put into operation after the communication base station is put into operation, they will not be involved in replacement within a few years. Therefore, it is of great significance to strengthen the maintenance of the storage battery and improve its use conditions so as to effectively prolong the service life of the battery. The on-line detection of batteries is currently unattended and plays an indispensable role in the maintenance of communication power.
Second, the technical status of the communication system battery The battery group is an important part of the base station to achieve DC uninterrupted power supply, and its investment and switching power supply equipment is basically the same. At present, most mobile base stations use valve-regulated sealed lead-acid batteries (VRLA batteries) that were developed at the end of the 20th century. Due to adopting the valve-controlled sealing structure, it is not necessary to add acid, add water for maintenance, and no acid liquid or acid mist is emitted. It can be installed in the same room as the equipment. Due to its small size, light weight, low self-discharge, low maintenance, long life, easy to use, safe and reliable, it is well received by users. However, we must see that on the one hand, the basic electrochemical principle of this type of battery remains unchanged, so its inherent electrical characteristics require not only no change, but more stringent requirements; on the other hand, this type of battery in the initial stage of promotion, the manufacturer's instructions Sometimes this type of battery is more or less called a "maintenance-free" battery, causing some maintenance personnel to think that such a battery does not require maintenance, so that battery maintenance and testing cannot receive due attention. This misdirection has so far been misleading. Have a profound effect.
From the perspective of the current usage of base station batteries, there is a general tendency that the battery capacity drops too quickly and the service life is short, and accidents involving dropping stations occur frequently. From the current quality of batteries produced by several large valve-controlled sealed battery manufacturers in China, they should be able to meet the requirements of various operators. Although manufacturers have different battery quality and performance. The quality factor of the battery should not be the main reason that affects the battery capacity of the base station of each operator at present. From the perspective of comprehensive factors such as product structure of valve-regulated sealed batteries, product performance, and on-site investigation of base station battery usage, combined with the use of exchange stations, the capacity of valve-regulated sealed batteries is normally used for 1 to 4 years. The decline should not be so rapid, resulting in the base station battery capacity decline is too fast, shortened service life should be mainly due to its base station use environment and maintenance related.
The main reasons that cause the base station battery capacity to drop too quickly and shorten its service life are:
First, the base station frequently loses power, has a long power outage, and has no regular power outages, so that the battery is frequently charged and discharged.
According to the anatomy of the existing battery manufacturers to dispose of the battery in the base station, the cause of the end of the battery life is the sulfation of the battery negative plate, which is a typical phenomenon of early battery capacity failure (PCL).
The causes of sulfation in the battery negative plate are as follows: The frequency of base station power outage is too high, the power is cut off several times a day, and even a continuous power outage for several days causes the base station battery to discharge again after the discharge has been fully charged, and the battery is undercharged. . If the undercharge occurs several times in a row, it will cause a cumulative loss of battery capacity. The battery capacity of the base station will drop in a relatively short period of time, and its service life will be terminated sooner. In general, the battery capacity decline rate is proportional to the number of times the base station battery is continuously undercharged. The intrinsic cause of the decrease in the battery capacity is that the battery discharges after being discharged without being fully charged, and the lead sulfate generated after the discharge of the positive and negative electrodes fails to completely recover lead dioxide and lead metal, respectively. The negative plate is discharged again, causing the battery to be undercharged, and the battery is undercharged several times. The negative plate is gradually sulphated, resulting in irreversible crystallisation of lead sulphate, especially when the battery is in a condition of deep over-discharge. The process will be more severe, and the rate of sulfation will be faster, resulting in the surface of the negative plate being shielded, and its function will be gradually reduced until failure, leading to a decrease in the service life of the battery until termination.
Second, the switching power supply setting parameters are irrational, the base station battery undervoltage protection setting voltage is too low, the reset voltage is set too low, so that the battery over discharge or even deep discharge phenomenon, from the other hand, accelerating battery negative plate sulfation.
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 discharges to a certain set voltage value, the switching power supply system will automatically cut off the power supply to some heavy load or all loads to protect the battery from overdischarge and ensure the service life of the battery.
If the battery's minimum under-voltage protection value is set too low, the battery will be over-discharged. Over-discharging and over-discharging over time after several times of over-discharging and over-discharging will not significantly affect battery life. In addition, if the switching power supply reset voltage is set Low, will make the battery discharge repeatedly in the discharge process occurs repeatedly; the specific battery minimum undervoltage protection value setting should be set according to the load current size, and the current base station battery minimum undervoltage protection value is generally set at a single battery voltage 1.8 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 less than 0.1C10A), the minimum undervoltage protection value of the base station battery should be set at a battery cell voltage of 1.8V or more.
Therefore, the base station battery undervoltage protection setting reference voltage is too low, such as long-term power failure of the base station, the battery will appear over-discharge, or even a small current over-discharge depth, and fully discharge the battery fully charged, restore capacity required to charge For a long period of time, a battery that is deeply over-discharged is generally difficult to fully recover its rated capacity under the condition that the base station has the only constant voltage charging. Therefore, the unreasonable setting of the switching power supply parameters exacerbates the sulfation of the negative plate of the battery from the other side, resulting in a decrease in battery capacity and a shortened service life.
Third, the use environment of the base station is worse. After the base station was powered off, the ambient temperature of the base station gradually increased due to no air conditioning. Or because of the air conditioning fault, the indoor temperature of the base station is high, thereby reducing the service life of the battery.
The indoor base stations are all equipped with air conditioners. The configured air conditioners are general cabinets or split type air conditioners. The long-term uninterrupted use of the air conditioners causes some of the base station air conditioners to malfunction and shut down. Sometimes the air conditioners are damaged and cannot be repaired in time. The indoor base stations are closed rooms. After the stoppage, the indoor temperature of the base station is greatly increased, and the room temperature of the color steel plate room can even reach more than 70Â°C.
On the one hand, even if the air conditioning is normal, and the base station has no AC power after the power outage, the air conditioner cannot be cooled. In particular, in the summer, the indoor temperature of the base station will rise significantly, thereby affecting the normal operation of the battery. This increases the amount of water lost inside the valve-regulated sealed battery and decreases the electrolyte saturation (decrease in electrolyte in the glass fiber cotton diaphragm), which results in a decrease in battery capacity and a shortened battery life.
On the other hand, due to the high indoor temperature, the thermal runaway effect of the battery will be exacerbated. As a result, the corrosion rate of the positive plate of the battery will increase, the plate will distort and expand, and the battery case may bulge or even crack. Finally, the battery capacity will rapidly decline and the battery life will be shortened. According to the accelerated life test, the ambient temperature rises by 10 degrees and the charging voltage is not adjusted, and the battery life will be shortened by half.
Fourth, after the base station is powered off, the battery discharges to the termination voltage. If the battery is not replenished in time, the battery capacity will decrease and the service life will be shortened.
Because some base stations are located in suburban areas or in remote villages and other places, the mains supply situation is poor, the number of mains power outages is long and the power outage time is long. Once the mains power is cut off, the battery is discharged to the termination voltage, and the mains electricity has not been restored. On the one hand, this may cause the battery to be over-discharged. On the other hand, after the battery is discharged, it cannot be supplemented with electricity in time. According to relevant data, if the battery cannot be replenished in time after discharge, the battery capacity will gradually decrease, after several cycles, Battery life will be significantly shortened.
In addition, the switching power supply output float voltage of some base stations is smaller than the set value and the display value by more than 1V, causing the battery to be undercharged for a long period of time.
In spite of these problems in the use of storage batteries for communication stations, the maintenance systems and maintenance personnel of our current communications operators cannot guarantee timely detection of battery problems, maintain them in a timely manner, and promptly replace backward batteries. To avoid dropping accidents. The battery on-line monitoring system came into being under this kind of environment.
Third, the need for battery monitoring Warburg Electric and Huahao Power Through the above analysis, the communication power supply is the basis of the communication network, the backup battery is the last barrier of the entire communication power supply, the battery, especially the battery in the communication room caused accidents Once it happens, it will cause huge losses! Therefore, in order to ensure the smooth operation of the communication network, each communication operator has strengthened the maintenance and testing of the battery in the communication room and introduced strict maintenance procedures of IEEE1189-2005. The current maintenance procedures mainly rely on periodic and mandatory verification discharges to monitor the health and charge status of the battery. However, due to the limitations of the maintenance technicians' preparation, the maintenance sites are remote, scattered, and the time for the inspection operation is too long, the completion rate of battery maintenance work in the entire communications industry is very low. The only feasible maintenance technique that does not have a blind spot is to use a battery monitoring system. Battery monitoring has advantages over conventional regular monitoring.
â€¢ Reduce the manual time required to manually measure and check the battery in the field.
Â· A systematic understanding of battery health through data provided by the monitoring system, without the need for calendar-to-site inspections, saving money.
â€¢ Continuous on-line battery system monitoring improves the reliability of power supply and reduces system downtime.
â€¢ Replace the battery before it affects other batteries in the same group, avoiding mutual influences and extending the overall battery system life.
â€¢ Know which batteries have reached replacement time and thus have greater initiative in battery procurement while reducing the occurrence of batch replacement batteries.
Â· Increase customer satisfaction and uptime by reducing power interruptions.
â€¢ Avoid loss of annual income due to power outages.
â€¢ The ability of the monitoring system to identify batteries with signs of damage enhances system reliability and thus increases production capacity.
Â· With our patented impedance measurement technology, reliable trend data will correctly show battery problems at the beginning of a battery failure.
Do not rely on measuring voltage to determine the battery status, voltage measurement can not accurately show the battery is good and bad availability.
The battery monitoring management system has remote monitoring, data acquisition and trend analysis functions, which can remotely monitor multiple battery systems and improve management efficiency.
â€¢ Predicting when and where the power company will lose power, the battery system cannot provide DC power.
â€¢ Accurately track and record the battery's real-time performance during a power outage.
Accurately monitor all items that have a direct impact on battery performance:
Although the installation of the battery online system will increase the cost of operation and maintenance once and for all, it will increase the battery life by 30%, reduce the maintenance workload by 75%, reduce the maintenance cost by 80%, reduce the occurrence of dropouts, and increase communications customers. The return of satisfaction is totally worth it.
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