Types and introduction

In the e-bike market, the most commonly used maintenance-free lead-acid batteries are the AGM type, which uses glass fibre spacer adsorption technology, and the GEL type, which uses colloidal electrolyte technology.

The principle of operation of lead batteries is that the anode (PbO2) and cathode (Pb) within the lead battery are dipped into the electrolyte (dilute sulphuric acid) and 2V of electricity is generated between the two poles. The chemical change in the discharge is that the dilute sulphuric acid reacts with the active material on the cathode and anode plates to produce the new compound "lead sulphate". The sulphuric acid component is released from the electrolyte by the discharge, and the longer the discharge, the thinner the concentration of sulphuric acid. The amount of sulphuric acid consumed is proportional to the amount discharged. The amount discharged or the amount of residual electricity can be determined by measuring the concentration of sulphuric acid in the electrolyte, i.e. by measuring its specific gravity. The chemical change in charging is that the lead sulphate produced on the anode and cathode plates during discharge is reduced to sulphuric acid, lead and lead peroxide during charging, so that the concentration of the electrolyte in the battery gradually increases, i.e. the specific gravity of the electrolyte rises and gradually returns to the concentration before discharge. When the lead sulphate in both poles is reduced to the original active material, it is the end of charging, and the cathode plate produces hydrogen and the anode plate produces oxygen.