A Lead Carbon Battery has better partial state-of-charge performance, more cycles, and higher efficiency
Replacing the active material of the negative plate by a lead carbon composite potentially reduces sulfation and improves charge acceptance of the negative plate.
Unlike regular lead acid, lead carbon can operate between 30 and 70 percent state-of-charge without fear of becoming sulfated. The ALC is said to outlive the regular lead acid battery, but the negative is a rapid voltage drop on discharge, resembling that of a supercapacitor.
The advantages of lead carbon therefore are:
– Less sulfation in case of partial state-of-charge operation.
– Lower charge voltage and therefore higher efficiency and less corrosion of the positive plate.
– And the overall result is improved cycle life.
Discover advancements made in lead acid batteries and how they benefit industry.
Most battery systems allow reasonably fast charging of one hour or so. The energy can also be withdrawn in about the same time, meaning that the charge and discharge times can be made similar. Lead acid is unique in that the battery can be discharged at a very high rate but requires more than 14 hours to fully charge. Lead acid also needs periodic equalization to de-sulfate the plates and correct other ills.
The answer to the inherent low charge acceptance relates to the formation and dissolution of lead sulfate on the negative electrode, which is pure lead. On discharge, lead sulfate adheres to the surface and dissolves again on charge. The process is sluggish and when trying to hasten the charge, excess electrons have nowhere to go; this leads to hydrogen generation and water loss. With age, the lead sulfate crystals engrain, which reduces the charge acceptance even further.
The positive electrode also contains lead sulfate, but it supports a high charge rate. It is clear that the negative electrode is the problem with lead acid batteries. New lead acid systems try to solve this problem by adding carbon to this electrode with promising results.