The failure study of lead-acid batteries is of great significance for the safety operation of the power system, and we have a summary discussion on this issue so that the reader has a summary understanding of this issue.1.1 battery loss
Lead-acid battery loss can cause an electrolyte specific gravity, resulting in corrosion of the battery positive electrode grid, so that the active material of the battery is reduced, thereby decreasing the capacity of the battery.
The difficulty of lead-acid battery sealing is the electrolysis of water when charging. When the charge reaches a certain amount of voltage (typically above 2.30V / monomer), oxygen is released on the positive electrode of the battery, and hydrogen is discharged. On the one hand, the gas is released from the acid mist pollution environment. On the other hand, the electrolyte is reduced in the electrolyte, and it must be added to the water over a period of time. The valve-controlled lead-acid battery is the product developed to overcome these shortcomings, and its product features are:
(1) Use a multi-quality plate gate alloy to increase the over-potential of gas release. That is, the normal battery board gate alloy releases the gas at 2.30 V / monomer (25 ¡ã C). After high quality plurality of alloy, the gas is released at 2.35V / monomer (25 ¡ã C), thereby reducing gas release.
(2) The negative electrode has excess capacity, which is 10% more than the positive pole. The oxygen released by the positive electrode release in the post-filled contact, the reaction, re-generating water, that is, O2 + 2PB→2PBO, PBO + H2SO4→The H2O + PBSO4 causes the negative electrode to be in an undersmunicate due to oxygen, and thus does not produce hydrogen. The oxygen of this positive electrode is absorbed by negative electrode lead, and then further chemically synthesized water, that is, the so-called cathode absorption.
(3) In order to let the oxygen released by the positive electrode flow to the negative electrode as soon as possible, a new ultra-fine fiberglass separator different from the microporous rubber separator used in the ordinary lead-acid battery must be employed. The holes are raised from 50% of the rubber separator to 90%, thereby easy to circulate the oxygen to the negative electrode, and then the synthesis of water. Further, the ultrafine fiberglass plate has a function of adsorbing the electrolytic solution of the sulfuric acid, so the valve-controlled sealing lead-acid battery uses a leancoal design, even if the battery is poured, no electrolyte overflow.
(4) The sealing valve is used to control the acid structure, so that the fog can't escape, to achieve safety, protect the environment.
During the above-described cathode absorption, since the resulting water cannot overflow in the sealing, the valve-controlled sealing lead-acid battery can be exempted from hydraulic maintenance, which is also the origin of the valve-controlled sealing lead-acid battery called the freevable battery.
The valve-controlled sealing lead-acid battery has a compact cushion, which can effectively prevent the acid from escaping. However, the sealed battery is not essential, that is, the battery should be alive during storage during storage; the charging voltage should not be alive with gas in 2.35V / monomer (25 ¡ã C); no gas is essential during discharge period . However, when the charging voltage exceeds 2.35V / monomer, it is possible to escape the gas. Since the battery body generated a large amount of gas in a short time in the battery body, it is not allowed to be absorbed by the negative electrode. When the pressure exceeds a value, the exhaust gas is exhausted by the unidirectional exhaust valve, although filtered out of the cryptoacid, but must Losing the battery, the valve-controlled sealing lead-acid battery is very strict, and cannot be caused by overcharge.
1.2 negative plate sulfate
The main active substance of the battery negative grid is a seaweed lead. The negative electrode grid occurs when the battery is charged, and the pBSO4 + 2E = Pb + SO4-, the oxidation reaction occurs on the positive electrode: PBSO4 + 2H2O = PBO2 + 4H ++ SO4- + 2E, the chemical reaction in the discharge process is the reverse reaction of this reaction. When the valve controlled sealing lead-acid battery is insufficient, there is a PB in the positive and negative pole grid of the battery, and the PBSO4 will lose activity. It cannot be involved in the chemical reaction, which is called the sulfated sulfate of the active substance, and sulfate reduces the active substance of the battery, reducing the effective capacity of the battery, and affects the gas absorption capacity of the battery, which will make the battery will fail.
To prevent sulfurization, the battery must be kept in a state of sufficient electricity.
1.3 Positive Polar Corrosion
Since the battery is lost, the electrolytic liquid has increased, and the excessive electrolyte acid is exacerbated to the positive electrode plate, so that the porosity of the positive electrode plate is increased, the electrolyte is relatively small, and the electrolyte active material is less, the battery capacity is low. Preventing Polar Corrosion Must pay attention to preventing battery fluid from occurring.
1.4 thermal out of control
Thermal out of control refers to a cumulative enhancement effect of the battery when the battery is charged, the charging current and the battery temperature are gradually damaged the battery. The root cause of heat loss is:
The ordinary rich-rich lead-acid battery is filled with a liquid in the positive and negative plates, so that the oxygen generated during the charging process cannot reach the negative electrode, so that the negative electrode is not polarized, which is easily hydrogen, which is easy to produce hydrogen. Battery.
Because it is not possible to dissipate heat through water, the heat generated during the VRLAB battery overcharge is more than the rich liquid-type lead-acid battery. It is more prone to heat out of control.
The floating charge should be reasonably selected. The floating voltage is a long-term charging voltage used for a long term, which is a factor affecting battery life. Under normal circumstances, the floating charge is set to 2.23V / monomer (25 ¡ã C) is relatively suitable. If it does not work according to this floating range, it uses 2.35V / monomer (25 ¡ã C), it will appear thermostable for 4 months; or 2.30V / monomer (25 ¡ã C), continuous charging 6 ~ It will appear in 8 months. If it is 2.28V / monomer (25 ¡ã C), there will be severe capacity decline in 12 to 18 months, which in turn leads to heat loss. The direct consequences of thermal out-of control are the shell drum bag, leakage, battery capacity, and final f Recommend: LiFePO4 Battery Manufacturer Energy storage battery Manufacturer Integrated machine energy storage battery series Manufacturer Lead lithium battery Manufacturer Outdoor Backup Battery Manufacturer Portable outdoor power supply Manufacturer Power battery Manufacturer Powerwall LiFePO4 Battery Manufacturer Battery rack Manufacturers Telecom LiFePO4 Battery Manufacturer Wall mounted battery storage Manufacturer China Lifepo4 Battery
