Principle of Corstal Lead-acid Battery

Principle of Corstal Lead-acid Battery

The working principle of VRLA batteries basically follows the traditional lead-acid batteries. The positive active material is lead dioxide (PbO 2), the negative active material is spongy lead (Pb), and the electrolyte is dilute sulfuric acid (H2SO4). The electrode reaction equation of VRLA batteries is as follows:

PbO_2_H_2SO_4 Pb_2PbSO_42H_2O

The Ratio of Two Valve-regulated Sealed Lead-acid Batteries

There are two main types of VRLA batteries, namely, glass fiber separator, cathodic absorption sealed lead-acid batteries (such as GNB, Hawke battery) and silicon gel sealed lead-acid batteries (such as Germany's sunshine battery).

The two kinds of battery plates are the same: the positive grid is made of lead-calcium-tin-aluminum quaternary alloy or low antimony multicomponent alloy, and the negative grid is made of lead-calcium-tin-aluminum quaternary alloy. A one-way safety valve is installed in the top cover of the battery with tight assembly and lean liquid design. The antimony-free lead-calcium-tin-aluminium quaternary alloy is used to increase the overpotential of hydrogen evolution in the negative electrode, thus inhibiting the hydrogen evolution. Meanwhile, a special safety valve is used to maintain a certain internal pressure of the battery.

The two kinds of battery partitions are different: they use the two ways of ultrafine glass fiber cotton (AGM) separator and silicon gel to "fix" the sulfuric acid electrolyte. They all make use of the cathode absorption principle to seal the battery, but the channels for oxygen from the positive pole to reach the negative pole are different. For AGM sealed lead-acid batteries, although most of the electrolyte in AGM diaphragm is maintained, 10% of the diaphragm pore must not enter the electrolyte. The oxygen generated by the positive pole is absorbed by the negative pole through this part of the pore to reach the negative pole. For gel sealed lead-acid batteries, the silicon gel inside the battery is a three-dimensional porous network structure made up of SiO2 particles as skeleton, which stores the electrolyte in it. After the silicon sol is changed into gel, the skeleton will shrink further, so that the cracks will run through the positive and negative plates. It will provide a channel for reaching the negative pole for the oxygen discharged from the positive electrode.

It can be seen that the difference between the two batteries is that the "fixed" way of electrolyte and the way of providing oxygen to reach the negative channel are different, so the performance of the two batteries is also different.