VRLA battery pack reliability detection method


  Author :Iflowpower – Portable Power Station Supplier

1 Introduction to the telecommunications center station, the analysis is the cause of the analysis. The battery is a VRLA (AGM) battery for use for 6 years. After examination, in the four sets of parallel battery packs, there are 2 ~ 3 batteries in each group, and when the battery pack is discharged, the unit voltage drop is faster, and the total voltage has been in front of the maintenance personnel.

Down to the off voltage, it leads to a communication interruption accident. The telecommunications center station in a certain province has also happened a serious accident in communication, indicating that there is a serious rigorous risotibility of VRLA spare batteries used in my country's communication industry. Important performance is: useful reliability detection of lack of rows in the middle and later Method and standard.

Combined with related experiences accumulated in VRLA batteries, it is proposed to detect the reliability of VRLA batteries in order to learn from the peers, and help the user's maintenance of VRLA spare battery packs. 2 Configuring VRLA spare battery pack configuration communication VRLA standby battery pack voltage is generally 48V; the central site generally puts a large number of 24 2VGFM series of large capacity 48V battery packs; non-center stations and marginal networks generally adopted a few Group 4 12VGFM Series 48V battery pack in parallel, or use a few sets of 24 2VGFM series small capacity 48V battery pack in parallel. The capacity size of the 48VVRLA standby battery pack is configured according to the load size.

The load current is generally designed as C10 / 15 (a). Under normal circumstances, the battery pack can adhere to the power supply 12 ~ 16h. For example, when the center station load is about 48V ¡Á 270A, the battery pack of 48V4000AH is generally configured, and 4 groups of 48V1000AH battery packs are commonly used, or 2 groups of 48V2000AH battery packs are used in parallel.

3UPS standby VRLA battery pack configuration UPS standby VRLA battery packs are commonly used with 220V, 380V battery pack. The capacity size of the battery pack is determined according to the load size, and the maximum load current size is generally from 1 to 2 hours of discharge. When the city electricity is interrupted, at least the power supply is about 1 to 2 hours under normal conditions.

4 The processing program at the time of electricity and electricity, the center communication station is generally prepared to have a diesel generator system. After the market is interrupted, the VRLA battery pack can start the diesel generator system to power the diesel generator system. For general communication machine stations, because it is unattended, the maintenance personnel generally have to arrive at the seat station, start the diesel power generation system, so the VRLA battery pack requires power supply 4 after the market is interrupted.

~ 5h or so. With regard to the UPS station, after the market is interrupted, the VRLA battery pack is only 15 to 30 minutes of power supply, and the relevant personnel will start the power supply of diesel power generation system. 5 Status after electricity and power of electricity in the city, although the VRLA spare battery pack capacity configuration margin is large, especially for communication spare power, battery pack capacity is about 40% of the rated capacity, at least 6 h and right, Enable the maintenance personnel to start the diesel power generation system, thereby ensuring the normal operation of communication.

However, there is often a major accident in reality, and there are many major accidents that interrupt more than 2 hours. This is because the VRLA battery pack usually is in a floating standby state, as long as there is very few partial battery capacity in each cell, when the battery is interrupted, the battery pack is powered by the battery pack. The decline is very fast, soon drums to the off voltage, so that the battery pack is shorter than the battery battery, people have not started to start the diesel power generation system, resulting in communication interruption accidents.

This is actually just the problem of VRLA battery capacity, and it is a problem with the reliability of VRLA battery, because we can't make capacity detection on the battery pack frequently. Therefore, it is important to have a method of judging the reliability of the capacity of the VRLA battery (or the judgment criteria). 6VRLA battery capacity reliability-related factors The central station is now floating, and the operation and maintenance personnel will detect the size of the battery floating voltage every other time.

However, the floating voltage size of the battery does not reflect the reliability of the internal state of the battery, often with a battery that is very functional, its capacity is small. Over the years, through the analysis and dissection of large amounts of capacity, the analysis and dissection of the failure, there is two types of facts: the first type: bus row, velvet erosion break. The following features: a) Negative electrode bus and negative electrode plate corrosion are severe, the negative electrode and the negative electrode bus bar are substantially corrosive and detached; b) The positive exclusion line is complete, no obvious corrosion signs; c) The positive plate is complete, No obvious deformation expansion, no obvious paste; D) the positive plate gate is complete; e) The negative electrode plate is complete, no hard, no obvious sulfate signs.

That is, regarding the first type of failure, the battery is etched and the balance is normal. Second type: PCL phenomenon. The following features: a) Positive extreme bus bar is complete, no significant corrosion; b) The negative electrode bus bar is complete, no obvious penetration corrosion; c) The positive plate is complete, no significant deformation expansion The phenomenon, the active material has no obvious paste; D) the positive plate gate is complete; e) The negative electrode plate is complete, no hard, no obvious sulfate signs; f) Early capacity loss in the positive electrode plate, so that the battery capacity is very little.

Therefore, there are two factors affecting VRLA battery capacity reliability: the first is a corrosion condition of bus rosks and panels, and is important to corrosion conditions of negative generals and negative plates. The second is the so-called PCL phenomenon, that is, early capacity loss. About VRLA batteries, important is the positive capacity loss of the positive electrode plate.

7VRLA battery reliability detection method for VRLA battery packs within 3 years, one capacity detection is per year, replacing C10 capacity than 10% lower than the highest capacity in the same cell. For battery packs for more than 3 years, check the corrosion of a junction, and then make capacity detection, and the specific operation method is as follows: (1) Packet detection, the fuse should be disconnected during detection; (2) open Valve; (3) Oblugging into the battery gas chamber with endoscope (ie, gastroscope), observes the corrosion of the bus bar and the slate, should pay attention to not damage the separator; (4) If the bus bar is more severely corrosion : The conversion is broken, and some panels and bus rows have corrosion fractures, and the battery should be replaced, and such a battery can no longer be recovered, it should be scrapped directly (Figure 1); Figure 1 Corrosive plate The ear and bus rosewart (5) are complete, and the tanker and bus welded solder can continue to be detected (Figure 2); Figure 2 Normal slate and bus bar (6) cover valve; (7) Capacity detection, classification, and recovery: battery capacity detection on the bus complete, no obvious corrosion; pick up the battery with a significant low capacity, centralized processing; capacity recovery. In a few years ago, there has been a more mature method to recover the battery capacity of the PCL phenomenon.

It can make more than 90% of the battery fully recovered capacity, and the remaining less than 10% of the battery can also increase its capacity. So far, tens of thousands of batteries have been successfully processed and recovered. During VRLA standby power floating, there is often a backward battery, which has a big relationship with the current VRLA standby power charging method, and the specific discussion is as follows.

8 Review and improvement of the current VRLA standby battery pack 8.1 The current VRLA standby battery pack charging method battery pack is in a floating state, all over 3 months, all over 3 months, all charge for about 12h. 8.

2 Effects of current VRLA spare battery packs The current VRLA standby battery pack floating plus regular charging method is not well to ensure that each battery in the battery pack is in a state of sufficient electricity. VRLA spare battery groups are unlikely to be completely consistent, there are always some capacity relatively backward battery cells, which have been discussed in detail in literature [1]. The battery pack is not fully charged in the floating battery cell, because in the case of floating charge (constant voltage limit charging), the battery end voltage is rapidly increased in the battery pack, so that The floating capacity flow value of the whole set of batteries is faster, so that the relative backward battery monomer is insufficient.

Some battery monomers are insufficiently charged, which can cause sulfate coarse granulation of partial active substances in the battery, making it more difficult to transfection into active substances in the battery when charging [1]. Over time, the sulfate crude crystal granulation of active substances in the backward battery is getting more serious, so that the capacity of the backward battery is faster. Even if periodic allocal charges do not cause all the sulfate of the thiral grain of the backward battery to the active substance, this is because the long-term floating charge, and then transferred, the charging voltage of the battery pack is rapid, so that all of them The current charging time is short, and the custody flow is faster, so that the lead of "crude grain" is not effectively "flush", which causes it to be completely dissolved to convert into active substances.

Therefore, the existing long-term floating plus regular basis is not better to ensure that the backward battery is fully sufficient, and the battery monomer having a small capacity in the VRLA spare battery pack is not well. 8.3 Improvement Improvement Only the high current is charged for a long time, so that the temperature of the battery is increased, in order to increase the sulfate solubility of the crude grains; under the large current "flush", it is easy to refine the sulfate of crude grains, so that It is more likely to dissolve; the high-current charging can play the use of "stirring" electrolyte, reduce the layering, improve the solubility of sulfate, and improve charging efficiency.

The effect of electrolyte stratification on battery charge / discharge, it has discussed in literature [1]. Dissolved leads in the prevention of sulfate can be easily converted into active substances. When charging, only the battery pack is first discharged, and then charge it, it can guarantee that there is a long time when it is charged, so that the backfall battery is fully sufficient.

Therefore, existing VRLA spare power charging method: long-term floating charge + regular charging method should be changed to: long-term floating charge + periodic discharge + regular basis method; or change to: + + regular discharge + regular basis. This requires VRLA alternate power supply maintenance personnel and related personnel to gradually improve understanding in long-term practice, and to switch the improvement and cooperation of the power supply manufacturers to promote the backward battery in the VRLA spare power supply in a suitable charge / discharge program. Anequent electricity, thereby increasing the reliability of VRLA spare battery pack capacity.

9 Recommendation VRLA spare battery pack system should have at least two or more battery packs to increase the reliability of the battery pack. Remove the long-term floating charge of the battery pack to recharge the charging system, which is changed to each set of batteries in the parallel battery group to: periodically discharge, equalize charging, stop charging for a period of time, and cycle, the specific: (1) The automatic (or manual) switching system is used, first separating one of the batteries in the parallel battery group with the remaining battery pack, and then discharges the battery load, the discharge capacity is about 40% of the rated capacity of the battery pack, and is detached The load is switched to the mains power supply before the voltage; (2) After the battery pack is discharged, the battery pack is balanced, and the equalization charging time is generally around 24h. (3) After the balance is completed, the battery pack is stopped, and the charging time can generally be 2 months.

(4) Then follow the above 3 steps. (5) After a set of battery balance is completed, the system is switched through the automatic (or manual) switching system, and then the other battery packs are identical discharge, equalized charging, stop charging, cycle. Or change the battery pack for a long-term floating charge + rechargeable charging system to long-term floating charge + periodic discharge + regular basis.

Regular load discharge power can be usually: 30% ~ 40% C10. VRLA standby battery pack is improved, to switch the power supply factory, so that the switching power supply automatically completes the charging method of the above functions, thereby greatly reducing the work intensity of operation and maintenance. For the VRLA battery pack for more than 3 years, the corrosion state detection of the slab and the ripple of the panel is made according to the contents described in Section 7 in Section 7.

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