Sulfation (accumulator)
In the sulfation of a lead-acid battery electrode thereof close to the surface of the lead sulfate - Crystals to ever coarser deposits together ( crystal growth ), which on the one hand reduces the active surface of the electrode and thus leads to a poorer responsiveness and thus power loss, on the other hand, the formed Lead sulfate crystals fall off the electrodes due to vibrations and form a layer of sludge on the bottom of the cell , which, if it gets so high that it touches both electrodes, causes a short circuit and the destruction of the battery cell .
Historic batteries in glass or hard rubber containers can be dismantled to remove the sludge, but when the lead batteries are closed, this is i. d. Usually no longer possible.
In VRLA accumulators (gel accumulators and AGM accumulators in which the electrolyte is bound by glass fiber mats), the fixed electrolyte prevents the crystals from falling down, and the vibration resistance increases.
Sulphation occurs to a greater extent when lead-acid batteries are stored uncharged for a long time, for example in boat or motorcycle "batteries" in winter.
The manufacturers of some electronically controlled chargers or additional circuits claim to desulphate lead-acid batteries by repeatedly generating short, stronger currents that break down or destroy the sulphate crystals and thus restore the capacity of the battery. The function is questionable, however, since the "desulfation" by (sometimes strong) current impulses of various frequencies and signal forms for the regeneration of sulfated lead-acid batteries has not yet been independently verified.
literature
- Angelika Vinke, Gerolf Marbach, Johannes Vinke: Chemistry for engineers. Oldenbourg Verlag, Munich 2008, page 181.
Web links
Detailed information on sulfation at Elektronikinfo.de