The reason and preventive measures of lead acid battery sulfuration

In the use of lead batteries, sulfuration problems was often mentioned, battery sulfuration refers to

the phenomenon that the active material on the battery plates are gradually turned into lead sulfate with coarse and hard crystals full of plate surface due to deep discharge (too much) or long-term insufficient charge, which will block the plates micropore and hinder the electrolyte penetration and conduction current, thus the battery charging and discharging performance is extremely deteriorated, and the actual capacity is seriously insufficient; and it could not be reduced to lead dioxide and spongy lead by conventional charging methods.

The coarse lead sulfate crystals are with poor conduct electricity and large volume, which will block the fine pores of active materials, hinder the penetration and diffusion of electrolyte, increase the internal resistance of the battery. At the same time, the lead sulfate is not readily converted to lead dioxide and spongy lead during charging. This kind of lead sulfate will lose the reversible effect, so that the effective substance of the plate is reduced, the discharge power is reduced, the service life is shortened, and there are colored spots appearing on the plate. Obviously, battery sulfuration has great influence on the performance of the battery, and even makes the battery scrap seriously.

1. The reasons for plate sulfuration 

1.1 Plate exposed electrolyte level

The electrolyte level in the battery is too low, so that the upper part of the plate contacts with the air directly, and the negative plate will be violently oxidized. When the car is driving, due to the fluctuation of the electrolyte level and the contact with the oxidized part of the upper part of the plate, the hard layer of lead sulfate with large crytals will be formed, so that the upper part of the plate is sulfurized, then the rest of the plate will bear large discharge energy, resulting in the sulfuration of the whole plate.

1.2 Initial charge or regular charge is insufficient, and there is no charge in regular.

1.3 The density of battery electrolyte is too high, so it is difficult to dissolve lead sulfate.

1.4 Lead battery is often discharged excessively or deep discharged with small current, so that a large number of lead sulfate is generated, and penetrated into the plate. The increase in the content of lead sulfate in the active substance is easy to coagulate and harden, blocking the pores of the active materials, the normal charging reaction is difficult to carry out in this case, only water decomposition.

1.5 The battery is in half discharge or discharge state for a long time. For example: battery leakage, internal short circuit and not eliminated in time, the charging current of the generator is small, which can cause plate sulfuration.

1.6 The electrolyte is not pure, which contains more organic matter and impurities, these organic matter and impurities not only promote the battery self-discharge, it is also the main reason to cause plate sulfuration. They attach to the negative plate during battery discharge, making it insoluble.

For the lead battery with serious sulfuration, "electric treatment", small current charging method is commonly used to eliminate. In the use and maintenance, it is important to take corresponding measures to reduce the sulfuration of the plate, in order to prolong the service life of the battery.

2. Measures to prevent plate sulfuration

2.1 The battery should be firmly installed, should keep the surface clean and dry.

2.2 To use high purity battery special sulfuric acid and distilled water to prepare the electrolyte, cannot use ordinary industrial sulfuric acid, also cannot use clean well water and rain. The prepared electrolyte should be stored in ceramic or engineering plastic containers, but not in metal containers. Plastic tool should also be used when filling, and ensure cleanliness.

2.3 As far as possible to make the battery in a sufficient state of electricity. After high current discharge, recharge in time. Car batteries are charged every three months by preventive desulfurization.

2.4 Select correct electrolyte concentration according to the seasonal changes, especially in winter with high concentration of electrolyte, after winter the concentration should be adjusted in time, high concentration of electrolyte should not be used all the year round. In addition, as long as the electrolyte level is not decreased due to leakage, only distilled water is allowed to adjust the height of the liquid level, but not electrolyte.