We know the battery is a component to store electrical energy. The question is, how can a battery store electrical energy? what's inside the battery?
We will discuss it.
The main thing, the battery works using chemical reactions. This chemical reaction result the electrons movements. So that electricity is created.
There are three main parts to the battery, it is sulfuric acid as the solution for the reaction. And the two plates are made of PB and PBO2.
When a load is connected to the plate, the PB and PBO2 plates are connected. This triggers the sulfuric acid molecules to break down into hydrogen and sulfate. The sulfate ion will stick to the PB plate. So that the PB plate becomes PBSO4.
Meanwhile, the hydrogen ion will take oxygen from the PBO2 plate. thus, it be an H2O molecule. in this process, there is an entry and release of ions on two plates. That activity, triggers a potential difference on the two plates. So that electrons flow and generate electrical energy.
This process will continue as long as the two plates are connected until all the sulfate ions stick to the PB plate. When all the sulfate ions have stuck, the sulfuric acid solution has become H20 and the electricity will stop flowing.
If this is the case, do we have to replace the solution? certainly not.
Because we can recharge the battery. When we give the current to the plates, it will reverses the reaction. So that the SO4 ions on the PB plate are released, the hydrogen and oxygen ions in the solution are also break. That makes the hydrogen ions stick to the sulfate ions, and the oxygen stick back with the PB plate.
When all the sulfate ions are released from the PB plate, the battery is fully charged and ready to use again.
So simply put, the battery works because there is a release and inflow of ions. It triggers the electrons to move so that electricity is formed.
Now take a look at the construction on the vehicle battery.
Vehicle battery generally has 12 volts of voltage. If we look inside, there are 6 cells connected in series. That means one cell has a voltage of 2 volts. In one cell there are 3 PB plates and three PBo2 plates. each plate placed crosswise.
At the top of the battery, there is a battery cover. In the cover, there are 6 caps, which are used to fill the sulfuric acid solution into each cell.
This caps, is also has ventilation holes. This is useful to stabilize the pressure inside the cell battery.
As we discussed earlier, during the charging process, the hydrogen ions will be released. And the hydrogen ions on the surface have the potential to evaporate. Thus increasing the pressure inside the cell battery. This ventilation hole becomes a way to remove hydrogen ions to keep the pressure stable.
But the risk is, when hydrogen ions are wasted, the solution volume will decrease. And there are sulfate ions that are still attached to the PB plate so that there is a scale on the PB plate. It makes the battery usage time decrease.
That's why, the battery has a usage limit. When the volume of the solution decreases, we just add the solution to each cell through the battery cap. But when the PB plate is filled with sulfate scale, the battery cannot be used for a long time.
And that's a sign, that the battery has reached the usage limit and must be replaced.
But there are types of batteries that don't have a cap. This is a VRLA battery. Actually this type is same with the flooded lead acid type we discussed. The difference, only at the top of the battery. VRLA battery has a relieve valve that will regulate the cell battery pressure without losing hydrogen ions.
So that we don't need to add sulfuric acid to the battery or what it is called maintenance free. That's the reason why the VRLA battery doesn't have a cap.
But still, the VRLA battey has usage limits. Because the VRLA battery still has a hydrogen leak but at a small amount. So that the lifetime of the VRLA battery can be longer than the flooded lead acid battery.
That is information about the vehicle battery.