Understand the hazards and characteristics of lead-acid battery plate vulcanization
2022 Jul 11 By admin 0 comment
  1. Plate vulcanization phenomenon and its hazards

Sulfation of lead-acid battery plates is a common phenomenon and a common fault. It is a layer of white sulfate with coarse grains produced on the plate for various reasons, which is often called plate sulfation, or plate sulfation or plate vulcanization for short. After the battery plate is vulcanized, the sulfate will block the fine pores of the active material of the plate, increase the resistance of the electrolyte infiltration, increase the internal resistance of the battery and reduce the capacity. When the plate is severely vulcanized, the sulfate crystal grains are difficult to dissolve in water under normal conditions, which will directly lead to the failure of the battery to be used normally and be scrapped in advance. Among the commonly discarded batteries, more than 65% are caused by the vulcanization of the plates. This shows that the vulcanization of the pole plate has great harm to the normal use and service life of the battery.

  1. Characteristics of plate vulcanization
    The vulcanization of battery plates often has the following characteristics.

(1) After the battery plate is vulcanized, it can be clearly seen that a layer of white sand-like substance is attached to the surface of the plate, which is a layer of coarse and hard sulfate on the surface of the plate. Sulfate grows tree-like during its formation, turning microscopic substances into macroscopic visible sand grains. At the same time, the color of the positive plate changes from dark brown to light brown or white, and the color of the negative plate changes from cyan to gray. This is an obvious manifestation of plate vulcanization.

(2) After the battery plate is vulcanized, the concentration (density) of the sulfuric acid solution decreases because the sulfuric acid is converted into the sulfate of the plate.

(3) After the plate is vulcanized, the internal resistance of the battery increases significantly.

(4) The charging time of the battery with plate vulcanization is much shorter than the rated charging time. That is to say, it does not take long to charge the battery, and the battery shows that it is fully charged. Even if the charging time is prolonged, it can no longer be charged.

(5) If the battery with vulcanized pole plate is charged with constant current with a current above C/10, the temperature of the battery will rise very quickly, and the temperature of the electrolyte will rise over 45°C.

(6) If the battery plate is severely vulcanized, air bubbles will be formed prematurely during charging or at the beginning of charging.

(7) If the battery with vulcanized plates is charged, it is often shown that it will be fully charged as soon as it is charged, and the voltage will soon reach the termination voltage of full charge, and then it will no longer be charged. And from the start of charging to the completion of charging, the voltage is reflected too high, usually 2.7V-2.9V.

(8) A fully charged battery will quickly emit light as soon as it is discharged, which is a reflection of the obvious reduction in capacity caused by the vulcanization of the pole plate. That is to say, a fully charged battery will be discharged in a short time, and the voltage will drop rapidly.

(9) The sulfate generated by the vulcanization of the pole plate has coarse grains, which is not easy to dissolve under normal circumstances, and is difficult to reduce to lead.