VIDEO – How a flooded lead acid battery is made

In this video we show the process that goes into making a flooded lead acid battery.


Over 200 years ago Alessandro Volta invented the first battery. He discovered that by placing copper and zinc discs on top of each other, and separating each with a brine soaked cloth, he could create an electrical power source.

His invention was called the Voltaic Pile in honour of the inventor and because it was, well, a pile of materials.

The basic principle of battery construction has not changed to this day.

Batteries are made up of cells. Each cell has a positive cathode and a negative anode.

The anode and cathode are kept physically apart with a separator but, for the cell to work, both are placed in contact with each other via electrolyte.

In this state the cell is almost inactive, it only has the potential to create electricity.

When connected to an appliance a chemical reaction takes place within the materials which causes electrons to flow through the circuit.

The materials which make up the cathode, the anode, the separator and the electrolyte vary depending on the type of battery or, as its known, the battery chemistry. There are numerous chemistries. And numerous types within each chemistry.

In this film we’ll look at how a flooded lead acid battery is made.

The process starts with a lead alloy cathode and a lead alloy anode. They are usually manufactured as meshes to maximise the surface area of the plates. A greater surface area means more power per plate.

A paste of lead oxides, sulfuric acid and water is applied to the plates which increases their effectiveness. Without this the power they can supply is limited.

The plates cannot physically touch each other or they will short out the battery so a separator is placed in between each.

Large numbers of plates are needed to provide any kind of meaningful power.

The plates and separators are slotted into a plastic casing in clusters. Each cluster is a cell. In this example the battery has 6 cells.

The positive cathodes of one cell are connected to the negative anodes of the next cell and terminal posts are added to create positive and negative connection points outside the case.

Each cell is filled with an electrolyte solution of sulfuric acid and a lid is put in place.

If a cell develops a fault or the battery is abused, charged or discharged too quickly the internal components will overheat causing gases to build up inside the case. In extreme situations these can cause a fire or an explosion.

To avoid this the lid contains vents, one for each cell, that allow these gases to escape.

The escaping gases can take vapourised electrolyte with them. Without the correct amount of electrolyte the battery’s power and lifespan are reduced. To counter this the vents are designed to be removed so electrolyte levels can be inspected and topped up.

The flooded lead acid battery is only one member of the lead acid family. There are also Valve Regulated Lead Acid, Sealed Lead Acid Gel and Absorbent Glass Mat Lead Acid variants.

And remember to check out our other videos about Lithium, Zinc Carbon, Nickel and Alkaline battery types.

For more information on all battery related topics simply search BatteryGuy Knowledge Base or visit us at forward slash kb

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