What are Gel Electrolyte Batteries?

Sealed gel technology (commonly referred to as "gel cells") was developed a number of years ago by the Sonnenschein Company in West Germany.  Simply stated, a gel cell is a lead acid battery that uses a thick chemotropic gelled electrolyte that is the consistency of candle wax once it "sets up" and is pressurized and sealed using special valves.  It uses the "recombination" technique to replace the oxygen and hydrogen normally lost in a wet cell battery and maintenance free and non-spill able. 

How Does A Gel Cell Work?

As noted above, a gel cell is a "recombinant" battery.  This means that the oxygen that is normally produced on the positive plates in all batteries, recombines with the hydrogen given off by the negative plates.  The combination of hydrogen and oxygen produces water which replaces the moisture lost in "wet cell" batteries.  Therefore, the battery is maintenance free, as it never needs water to be added.

The oxygen is trapped in the cell by special pressurized sealing vents.  It travels to the negative plates through tiny fissures or cracks in the gelled electrolyte.  The sealing vent is critical to the performance of the gel cell.  The cell must maintain a pressure of approximately 1 an 1/2 lbs. per sq. inch, otherwise the recombination of the gases will not take place and the cell will not perform.  Likewise, the valve must safely release excess pressure that may be produced during charging.  Otherwise, the cell could be irreparably damaged.  It is important to note that a gel cell must never be opened once it leaves the factory.  If opened, the cell loses its pressure and the outside air will "poison" the plates and cause an imbalance that destroys the recombinant chemistry. 

What Is The Difference Between Gel Cell & SLA Batteries?

While both are recombinant batteries and are sealed valve regulated, the major difference is that the "starved" or "absorbed" electrolyte battery has only enough electrolyte added at the factory, prior to sealing on the cap, to soak the separator.  Therefore, it is also non-spill able by virtue of the fact that all of the electrolyte is trapped in the sponge-like separator material (AGM).  There is no "free" electrolyte to spill if tipped or punctured.  This allows either battery to operate in any position, however installation upside-down is not recommended. 

Union Battery Corporation