The working principle of lead-acid batteries
1. Lead-acid battery discharge: H2SO4↓, H2O↑, the specific gravity of the electrolyte p↓; Charging: p↑. The degree of discharge of the new battery can be judged by p measurement.
2. Actually for lead-acid battery discharge:
PbO2 + 2H2SO4 → Pb4++2 SO42-+2H20
Positive plate active material (positive plate ) (Liquid)
positive potential +2V P,
Pb → electrolysis, Pb+ + 2e (negative plate) → negative potential -0.1V
(negative Dissolved in electrolyte
External circuit newly opened: Eu003d2.1V (single cell voltage) 2-(-0.1)u003d2.1V
External circuit connected: negative 2e→Positive plate, combine with Pb4+ to generate Pb2+.
Theoretically, PbO2 and Pb on the plate of a lead-acid battery will become PbSO4 until the discharge is over. In fact, the electrolyte cannot penetrate into the innermost layer of the active material of the plate. Only part of the active material on the board becomes lead sulfate.
The pole plate should be as thin as possible and have a large area.
3. Increasing the discharge current: In a single cell, multiple sets of positive and negative plates are connected in parallel to increase the degree of plate holes and reduce the thickness of the plates.
4. The charging process is opposite to the discharging process:
5. Lead-acid battery charging characteristics
Three criteria for judging battery adequacy:
1. The charging voltage U reaches max and does not increase after 2h;
2. Electrolyte density>sc reaches max and does not increase after 2h;
3. The battery violently releases a lot of bubbles and the electrolyte boils;
6. Lead-acid battery discharge characteristics
1. Single cell battery voltage drops to discharge termination voltage (as shown in the table);
2.p ↓The minimum allowable value is 1.1g/cm3.