What is an Accumulator? How Does Accumulator work?
The means that convert chemical energy into electrical energy and store electrical energy into chemical energy are called accumulators. When electrical energy is taken from an accumulator, some chemical changes occur in the electrolyte and electrodes, and after a while, electromotive force (emf) decreases. When a current is passed through this accumulator in the opposite direction, chemical changes occur in the electrolyte and electrodes and the Emf of the battery increases.
How Accumulators are made
The active substance of the negative plate of a full battery is spongy (porous) lead (Pb), the dark brown color of the positive plate (Pb O2), and the electrolyte is aqueous sulfuric acid with a density of 1.27. The amount of electrical energy drawn from an accumulator depends on the amount of substance undergoing chemical change. It is desirable that the amount of active substance in the plaques in contact with the electrolyte be as high as possible. For this, there are many positive and negative plates in a battery. The positive plates were connected by a bridge and the two ends were removed.
The positive terminal is called the positive pole of the battery and the negative terminal is called the negative pole of the battery. The negative structure of a battery and the placement of the plates can be seen in the section of the battery. The negative structure of an accumulator and the placement of the plates can be seen in the battery section. The number of negative plates in an accumulator is one more than the number of positive plates. The placement of the plates is shown together with their separators. The active substance in the plates is filled into grid-shaped cages made of lead-antimony alloy.
Chemical Events in the Discharge of a Leaded Battery
Let’s start to discharge the full battery by closing its switches. Aqueous sulfuric acid consists of positively charged hydrogen (H2 +) and negatively charged sulfate (So4-) ions. The sulfate ion combines with lead by giving its negative charge to the lead plate and lead sulfate (PbSo4) is formed. The sulfate ion combines with the lead by giving its negative charge to the lead plate and goes to the lead sulfate plate, after giving its charge to this plate, the lead peroxide combines with the oxygen of the plate to form water (H2O).
The hydrogen ion of sulfuric acid, which is in contact with the lead peroxide plate, combines with the oxygen of the lead peroxide to form lead sulfate (PbSo4). Thus, both plates turn into lead sulfate. The battery continues to give current to the external circuit until both plates turn into lead sulfate. Because when two plates in electronics are of the same type, the potential difference between the plates becomes zero.
Three changes occur at the moment of battery discharge:
1- The acid density in the electrolyte weakens. This drops Emf.
2- The active ingredients of the plates, lead peroxide, and lead, turn into lead sulfate.
3- The internal resistance of the battery increases, the Emf decreases.