1.5V rechargeable battery

　　Analysis and research on 1.5V rechargeable batteryselection, acceptance, use and maintenance

　　1 Introduction The 1.5V rechargeable batteryis the last link that the system reliability depends on, and it is also the weakest link in the system reliability. Many major accidents originate from the failure of the battery. Only important systems are equipped with 1.5V rechargeable batterybackup power systems. Although some batteries seem to have no problem from installation to designated withdrawal, the actual situation may be...

　　1 Introduction

　　The 1.5V rechargeable batteryis the last link on which system reliability depends, and it is also the weakest link in system reliability. Many major accidents originate from 1.5V rechargeable batteryfailure. Only important systems are equipped with 1.5V rechargeable batterybackup power systems. Although some batteries seem to have no problem from installation to designated withdrawal, the actual situation may be that the 1.5V rechargeable batterypack has never been used to discharge. Once the 1.5V rechargeable batteryis needed for power supply, and it is not confirmed whether the 1.5V rechargeable batterycan supply power, it will cause heavy losses, or even is catastrophic. Therefore, the purchase, acceptance, testing, maintenance and upkeep of batteries must not be taken lightly.

　　2 1.5V rechargeable batteryselection and specifications

　　To make the 1.5V rechargeable batterysystem have high reliability, we must first select the 1.5V rechargeable batterycorrectly. There are differences in the design of UpS and communication batteries: some batteries have better cycle characteristics; some batteries are suitable for starting; some batteries are suitable for low-temperature environments; Some batteries are suitable for small current discharge, etc. When selecting batteries, it is very necessary to understand the differences in technology and use of various batteries, and to fully understand the electrical performance of the 1.5V rechargeable batteryand the user's own needs for product performance.

　　User demand for products. For example, backup power system capacity requirements, frequency of use, environment of use, main purpose, service life, reliability requirements, instantaneous discharge rate, rectifier specifications and other battery-related performance requirements.

　　Supplier’s product commitments. Product design parameters (1.5V rechargeable batterymodel, appearance size, rated capacity, rated voltage, weight, weight specific energy, volume specific energy, design life, number of positive and negative plates, thickness ratio of positive and negative plates, electrolyte density, plate type, grid material, etc.), product electrical performance parameters, actual service life of the product, installation and use environment, performance and price of different models, warranty period of different types of products, etc.

　　Calculate the discharge capacity during a total power outage to select the appropriate 1.5V rechargeable batterymodel:

　　Cc=Kk·Cs/Kc

　　Kk—capacity reserve coefficient, taken as 1.25.

　　Kc—capacity conversion coefficient, corresponding to a discharge termination voltage of 1.8V. Check the design manual for the relationship curve between 1.5V rechargeable batterydischarge capacity and discharge time.

　　Cc—long-term discharge capacity under full stop state due to accident.

　　The 1.5V rechargeable batteryspecifications are correspondingly explained in IEEEStd.485. After the user determines the cycle life of the system, the 1.5V rechargeable batteryspecifications can be selected relatively easily. In the process of selecting a suitable 1.5V rechargeable batteryfor use, you should also consider the following factors:

　　Kt – temperature correction factor, allowing the 1.5V rechargeable batteryto operate normally in the expected lowest temperature environment.

　　Kd – the design margin factor that allows the 1.5V rechargeable batteryto compensate for the additional load.

　　Ka – the aging factor that enables the 1.5V rechargeable batteryto meet its service life.

　　31.5V rechargeable batteryroom design

　　The layout and environment of the 1.5V rechargeable batteryroom will greatly affect system reliability and service life. The following points should be taken into consideration during design:

　　Temperature control: High temperatures will shorten the life of the battery. In a 92F° environment, the 1.5V rechargeable batterylife can only reach half of its rated life. Low temperature will reduce the capacity of the battery. In a 62F° environment, the 1.5V rechargeable batterywill lose about 10% of its capacity. Therefore, the temperature of the 1.5V rechargeable batteryroom must be controlled centrally. The difference between the highest and lowest temperatures should be less than 5F°. Otherwise, the float voltage of the 1.5V rechargeable batterycell will be unstable.

　　Maintenance passage: There must be a passage in the 1.5V rechargeable batteryroom for maintenance personnel to use when replacing batteries and cleaning. Without this passage, all maintenance work cannot be carried out. If the cabinet is filled to the brim, maintenance personnel may not be able to access the 1.5V rechargeable batteryterminals. When a battery's performance degrades in three months or less, maintenance personnel simply don't realize the seriousness of the problem.

　　Safety: Issues to consider in terms of safety include: acid mist discharge outlets, cabinet ventilation and heat dissipation, cleaning tools, lighting effects, and convenient exits. Generally do not use 1.5V rechargeable batteryracks higher than two levels.

　　4. Acceptance and storage of batteries

　　Users must follow correct procedures to accept and store batteries to ensure quality during installation and use. Here are the three most important steps:

　　(1) Damage inspection: After the 1.5V rechargeable batteryis delivered, it must be inspected immediately so that the user can quickly understand the damage or missing parts. Because if the problem is reported too late, it will not only increase the loss, but also make it difficult to claim compensation from the manufacturer or supply company.

　　(2) Installation can only be carried out after completing the above inspections. After completing the installation, charge it. After it is fully charged, float charge it for 72 hours, and then conduct a full capacity test. The 1.5V rechargeable batteryacceptance is only completed if it passes the capacity test.

　　(3) After the acceptance is completed, the 1.5V rechargeable batterymust be fully charged again. After float charging for 72 hours, its internal resistance is measured as the base value for judging its performance in the future. If the internal resistance values are all within ±5% of the average value, the resistance values are considered to match. Batteries exceeding 5% of the average value are best asked to be replaced by the supplier, because the life of 1.5V rechargeable batterypacks with internal resistance values that differ too much will be affected.

　　The storage place should be cool and dry. High temperature and rapid self-discharge rate will increase the internal consumption of the battery.

　　If recharging is necessary, most manufacturers' guarantees will not be fulfilled if the batteries have been stored for more than six months and the user has not boosted them. If the 1.5V rechargeable batteryis stored in a high temperature environment of 92F°, this time will become three months.

　　5. Installation of 1.5V rechargeable batterypack

　　Installation is also an important step. Because the quality of this work will affect the reliability of the 1.5V rechargeable batterysystem operation. Most users do not realize the importance of 1.5V rechargeable batteryinstallation. 1.5V rechargeable batteryinstallation work should be completed by trained personnel or the manufacturer. Many 1.5V rechargeable batterydamages are caused by the inexperience of the installer.

　　Here are some common corruption scenarios that occur during installation:

　　The pole seal is leaking: The reason may be that the pole is lifted when transporting the battery, or the cells connected between the batteries are not arranged neatly. As the 1.5V rechargeable batteryis pulled into the installation position, the connector between the batteries is in a tight state, causing extrusion between the pole and the seal in front of the connector. Leakage of the pole seal will inevitably lead to corrosion of the connector between the batteries.

　　Housing damage: This is caused by the use of unapproved chemical materials. Some people use oil-based grease to facilitate 1.5V rechargeable batteryinstallation. After installation, use unknown compounds to clean the battery. Since many compounds will corrode the casing material, the 1.5V rechargeable batterycasing may rupture and the electrolyte may leak.

　　6. Use of batteries

　　6.1 Effect of operating temperature:

　　(1) The relationship between capacity and temperature: As the ambient temperature increases, the capacity of the 1.5V rechargeable batterywill increase within a certain range. Too low a temperature will cause sulfation of the negative electrode, and too high a temperature will accelerate the corrosion of the 1.5V rechargeable batterygrid and the loss of 1.5V rechargeable batterymoisture.

　　(2) The relationship between float charge voltage and temperature: The calculation formula of float charge voltage at different temperatures is VT=(2.2~2.27)-(T-25)×0.03. If the float charge voltage is too high, the float charge current will increase, accelerating the corrosion rate of the grid, and reducing the 1.5V rechargeable batterylife; if the float charge voltage is too low, the 1.5V rechargeable batterycannot maintain the charging state, causing sulfation, reducing the capacity, and reducing the 1.5V rechargeable batterylife. .

　　(3) The relationship between the equalizing voltage and temperature: The calculation formula of the equalizing voltage at different temperatures is VT=(2.30~2.35)-(T-25)×0.05. The equalizing charging voltage needs to be adjusted with the ambient temperature. The specific charging voltage is subject to the manufacturer.

　　(4) The relationship between life and temperature: T25=T design × 2 (T actual -25)/10. Increased temperature will damage the 1.5V rechargeable batteryand reduce its service life.

　　6.2 Charging and discharging system of valve-regulated battery

　　(1)Constant current and voltage limiting charging

　　I10 current is used for constant current charging. When the 1.5V rechargeable batterypack terminal voltage rises to (2.30~2.35V) × N voltage limit value, it will automatically or manually switch to constant voltage charging.

　　(2)Constant voltage charging

　　Under the constant voltage charging of (2.30~2.35V) The device will automatically or manually switch to normal float charging operation, and the voltage value should be controlled to (2.23~2.28V) × N.

　　(3) Supplementary charging

　　In order to make up for the undercharge caused by improper adjustment of the float current during operation, it cannot compensate for the loss of 1.5V rechargeable batterycapacity caused by self-discharge and creepage leakage of the valve-controlled battery. Set the time as needed (usually 3 months) and the charging device will automatically or manually perform a constant current limited voltage charging, constant voltage charging and float charging process. Keep the 1.5V rechargeable batterypack at full capacity at all times to ensure safe and reliable operation.

　　6.3 Verification discharge of valve-regulated battery

　　After long-term use of the float charging operation mode with limited voltage and current or the operation mode with only limited pressure and no current limit, it is impossible to determine the current capacity of the valve-controlled 1.5V rechargeable batteryand whether it is dehydrated or cracked inside. Only through verification discharge can the existence of the 1.5V rechargeable batterybe found out. The problem.

　　(1) A set of valve-regulated batteries

　　When the system has only one set of batteries, it cannot exit operation, nor can it perform full verification discharge. It can only discharge 50% of the rated capacity. During the discharge process, the 1.5V rechargeable batterypack terminal voltage must not be lower than 2V×N. Immediately after discharge, I10~2I10 current should be used for constant current limited voltage charging and constant voltage charging and float charging. Repeatedly discharge and charge 2 to 3 times, the 1.5V rechargeable batterypack capacity can be restored. 1.5V rechargeable batterydefects can be found and dealt with. If there is a spare valve-regulated 1.5V rechargeable batterypack for temporary use, the valve-regulated 1.5V rechargeable batterypack can be fully verified for discharge.

　　(2) Two sets of valve-controlled batteries

　　When the system has two sets of valve-regulated batteries, one of the valve-controlled 1.5V rechargeable batterybanks can be fully discharged first. Use I10 constant current to discharge. When the 1.5V rechargeable batterypack terminal voltage drops to 1.8V×N, stop discharging. After 1 to 2 hours, use I10 to 2I10 current for constant current and voltage limiting charging and constant voltage charging and float charging. By repeatedly discharging and charging 2 to 3 times, problems with the 1.5V rechargeable batterycan be detected and the capacity can be restored. If after three full verification discharges and charges, the capacity of the 1.5V rechargeable batterypack does not reach more than 80% of the rated capacity, it can be considered that the service life of this set of valve-controlled batteries has expired and should be replaced.

　　(3) Valve controlled 1.5V rechargeable batterycheck discharge cycle

　　Newly installed or overhauled valve-controlled 1.5V rechargeable batterypacks should undergo a full verification discharge test. In the future, a verification test will be conducted every 2 to 3 years. Valve-regulated batteries that have been in operation for 6 years should undergo a verification discharge test every year.

　　[page]61.5V rechargeable batterymaintenance

　　The 1.5V rechargeable batterymaintenance requirements are clearly stated in IEEE document 1188 (VRLA battery), and must be performed by skilled personnel in accordance with the requirements of the standard. Any user who strictly implements the IEEE standards will have a reliable backup 1.5V rechargeable batterysystem.

　　The biggest issue involved in maintenance work is personnel safety, especially the high-voltage 1.5V rechargeable batteryin the UpS. Unskilled personnel who do not fully understand Ohm's law cannot work on high-voltage batteries. Many newly installed UpS systems use non-isolating transformers, which creates a high AC voltage to ground at each pole terminal in the 1.5V rechargeable batterystring, plus there is no known additional space to access the pole terminals. . Therefore, installation work inside the UpS cabinet is extremely dangerous.

　　Maintenance procedures must use consistent data measurement and recording methods to enable further analysis of the battery. at the same time,

　　The 1.5V rechargeable batterythat should be replaced can be inferred, and the data can be used to identify existing problems, making system problems obvious. Ensure the safety of backup power systems while providing the necessary evidence for claims.

　　6.1 Routine maintenance content: The 1.5V rechargeable batteryshould check the following items every week:

　　(1) To remove surface dust, use a lint-free soft cloth or other similar materials. (2) Check whether the connections are loose, heated or corroded. Clean it in time and take anti-rust measures. (3) Whether the 1.5V rechargeable batterycase is leaking or deformed. (4) Check whether there is acid mist escaping around the pole and safety valve, and seal the valve-controlled battery. (5) 1.5V rechargeable batterypack float voltage. (6) When the float charge voltage of each cell is lower than 2.18V, the 1.5V rechargeable batteryshould be balancedly charged. (7) Check the ambient temperature every day and adjust the float voltage in time. It is best to use a power supply with automatic temperature compensation. For accurate data, please refer to the data provided by the 1.5V rechargeable batterymanufacturer.

　　6.2 Quarterly and annual maintenance

　　6.2.1 Internal resistance and resistance test

　　The internal resistance of the 1.5V rechargeable batteryand the connection resistance between the single modules should be measured once a quarter. For valve-controlled batteries that have been used for more than 4 years, the test cycle should be shortened by half. The measured resistance value is significantly higher than the last time or close to the failure judgment value, close to 1.25 times the base value. The test cycle should be shortened to half or 1/4 of the original value. When the base value is reached or exceeded, the entire set of complete capacity test or power-down test should be performed. When the average internal resistance of the entire 1.5V rechargeable batterypack is close to reaching or exceeding the base value, the charge and discharge test of the single cell should be performed. During the activation test, when the internal resistance of the cell exceeds the base value by more than 50%, the 1.5V rechargeable batteryshould be replaced without hesitation. When performing an unconditional capacity test or activation test, use the system to conduct a short-term charge and discharge experiment of about half an hour, subject to the safety conditions of the system. Measure its internal resistance again. If it exceeds the failure limit, the 1.5V rechargeable batteryshould be replaced. If the above test is unconditional, the monomer whose internal resistance reaches or exceeds the failure value should be replaced immediately. When replacing the battery, the principle of internal resistance matching should be considered. When a large number of batteries are replaced and the total number reaches more than 10%, and a 1.5V rechargeable batterywith a better internal resistance cannot be found, the entire 1.5V rechargeable batteryset should be replaced.

　　6.2.2 Capacity test

　　Sealed VRLA batteries undergo a full capacity test or deep discharge test at least once a year. When the average internal resistance of the entire set is equal to or exceeds the failure limit, a complete capacity test must be performed. When the internal resistance of the monomer is equal to or greater than the failure limit, the monomer capacity and activation must be performed.

　　6.3 Special maintenance

　　If the 1.5V rechargeable batterypack has experienced abnormal conditions (such as service discharge, overcharging or extremely high ambient temperatures, etc.), then a test should be performed. to confirm that the 1.5V rechargeable batterypack is not damaged. The inspection contents are the same as those required for annual inspection.

　　7 tests

　　Whether a 1.5V rechargeable batterysystem can function can be tested in the following ways:

　　(1) Capacity test: Because this is a test based on formal theory, and it can determine the position of the 1.5V rechargeable batteryin the life cycle. Newly installed systems must undergo capacity testing as part of acceptance testing.

　　(2) Power-down test: This method uses actual load to test the 1.5V rechargeable batterysystem. Through the test results, an objective and accurate 1.5V rechargeable batterycapacity can be calculated. It is recommended that when testing, try to get as close to or meet the time requirement as possible. If a system using VRLA batteries fails to maintain its original voltage after loading, consider fully testing it. After the VRLA 1.5V rechargeable batteryis added to the load, it will partially dry up, which is normal. However, if the voltage on the terminals drops rapidly, it means that the energy has been exhausted and the 1.5V rechargeable batterycan no longer support the normal operation of the system.

　　(3) MeasurementInternal Ohmic Resistance: Internal resistance is the best indicator of 1.5V rechargeable batterycondition. Although this test method is not as 100% absolute as the load test, measuring the internal resistance can detect at least 95% of problematic batteries. Load testing is the best way to determine 1.5V rechargeable batteryperformance, but testing is expensive. If necessary, testing internal resistance is a relatively reasonable compromise. According to this plan, VRLA should measure the internal resistance every quarter.

　　(4) Voltage deviation value of valve-controlled 1.5V rechargeable batteryduring operation:

　　Therefore, it is not scientific enough to judge the quality of the 1.5V rechargeable batterysimply by measuring the voltage. To achieve high reliability in a 1.5V rechargeable batterysystem, you should start by purchasing suitable batteries, ensuring that they are stored and installed correctly, and that the batteries are maintained and tested according to the guidelines in IEEE standards. Configuring a permanently installed monitor or online monitoring system will provide the greatest guarantee for system reliability.

　　81.5V rechargeable batteryreplacement standards

　　When the actual capacity of the 1.5V rechargeable batteryis less than 80% of the manufacturer's rated capacity, the 1.5V rechargeable batteryshould be replaced. The timing of replacement is a function of the capacity sizing standard application, which also enables comparison of possible capacity boundary values under various load conditions. A capacity of 80% indicates that even if the 1.5V rechargeable batteryhas the ampere (current) capability to meet the load capacity of the DC system, its rate of degradation is increasing. Failure to meet the results of service tests or the addition of new loads may require 1.5V rechargeable batteryreplacement. Physical properties such as unusually high cell/element temperatures. It is usually also a condition for deciding to replace the entire 1.5V rechargeable batterypack or a single battery. The reverse polarity of the cell is a good indicator of the cell/unit that needs to be replaced for further verification. If the unit/unit needs to be replaced, its electrical characteristics must be compatible with the replacement unit/unit and must be tested before installation. It is not recommended to replace cells/cells when the 1.5V rechargeable batterypack is close to failure.

　　If the voltage of a cell is still low after correction operation (equalization), it is also a good indicator that the cell/cell needs to be replaced for further verification. Cells/elements that fail during continuity testing must be replaced as soon as an uncorrectable condition exists.

　　9 Conclusion

　　This article provides a detailed introduction to the purchase, acceptance, use and maintenance of batteries. Correct understanding of batteries, scientific use of batteries, mastering the methods of testing and selecting batteries, and reasonable and reliable management and maintenance of batteries can ensure a long life of batteries and safeguard the interests of investors.

　　References [1] DL/T724-2000, Technical regulations for operation and maintenance of 1.5V rechargeable batteryDC power supply devices for power systems. [2] IEEEStd1188-1996, IEEE recommended maintenance, testing and replacement methods for valve-regulated lead-acid VRLA batteries used in stations. [3] YD/T799-2002, Valve-regulated sealed lead-acid batteries for communications.

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