Factors affecting valve-operated maintenance-free battery life

Date:Jul 16, 2019

There are many factors affecting the actual service life of VRLA batteries, and the main functions are as follows:

1. Overcharge: In the initial stage of charging, the battery terminal voltage is low. At this time, no hydrogen-oxygen gas is precipitated, and then the lead-acid battery terminal voltage gradually rises. When the battery terminal voltage rises to a certain value, the battery will be precipitated. A lot of gas. When the battery terminal voltage rises to 2.30 - 2.35 V / only (this voltage is called the gas generation point voltage), the gas in the battery increases remarkably. As the charging progresses, more and more PbO2 on the surface of the electrode, and PbSO4 has gradually decreased, and the rate of oxygen evolution of the positive electrode will become larger and larger, and at the same time, the negative electrode of the battery also begins to evolve hydrogen. Therefore, overcharging will cause the battery to generate a large amount of gas, which will cause the battery to lose water and lead to premature effectiveness, and the capacity will decrease early.

2. Over-discharge: A discharge that is performed to periodically detect the charge capacity of the battery during operation is called a check-discharge. The VRLA battery has a constant current discharge of 1.80V at a constant current of 0.1C. The continuous discharge at the end of discharge is called overdischarge. Once it enters the overdischarge state, the battery terminal voltage will accelerate and fall, which will easily cause power interruption and also cause active material transition. The consumption causes the pores of the active material and the reaction area reserved for the next charging to decrease, which causes difficulty in subsequent charging and maintenance of the battery, and finally the battery cannot be filled, and the capacity is greatly reduced.

3. Temperature: The operating conditions of the battery also have an important effect on the life of the battery. If used for a long time at high temperatures, the battery life is reduced by half for every 10 degrees increase in temperature.

4. Negative plate sulphation: VRLA battery that can perform normal work, lead plate discharge product lead sulfate is smaller particles, it is easy to recover to fleece lead when charging, but some battery discharge products are poorly soluble large particles of lead sulfate, and It cannot be reduced to fluffy lead during charging, and this negative plate is called sulfation. The reasons for the sulphation of the negative plate are: insufficient long-term charging of the battery, long-term discharge at high temperature, long-term discharge, high-level electrolyte concentration and battery water loss. Sulfation of the negative plate will directly cause the capacity of the battery to shrink. An effective way to prevent sulphation of the negative plate is to always keep the battery content full.

5. Long-term floating state does not discharge: long-term non-discharge will lead to the precipitation of active substances inside the battery. If the active substance is in the precipitation state for a long time, it will be difficult to participate in the chemical reaction inside the battery, resulting in loss of battery capacity.

6. The new battery should be tested for discharge after it has been installed. It should be used to check the capacity of the battery. After three years, it should be done once every year. The effect is two: one is 30%--50%. It is used to prevent the precipitation of active substances inside the battery for a long time without discharging. The second is to discharge 80%--100%, which is used to check the charging capacity of the discharge test battery. The third is to check the discharge to find the bad battery so that it can be replaced in time because the battery The hazard of having a bad battery in the group is very large.

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