The expansion agent of the cathode plate of the humic acid lead storage battery has the advantages of improving the capacity.
The humic acid application in the battery is very valuable. Improving the low temperature and room temperature starting performance of the battery. Preventing the caking of the cathode active material in the cycle process. Improving the working ability of the cathode heat preservation and thawing. Saving lead powder and prolonging the service life of the battery etc. Which are indispensable additives in the production of the lead battery at present. According to preliminary calculation, the annual demand of humic acid cathode plate expander is about 1000T in China.
Application of Humic Acid in Lead-sulfuric acid battery.
Lead-sulfuric acid battery is a kind of reversible battery which is widely used. This kind of battery is recharged and discharged to realize the conversion of chemical energy and electric energy to each other. The electrode is composed of two groups of lead dielectric latticed plates: PbO2 and spongy metal lead particles are filled in the holes of anode and cathode plate respectively. And dilute sulfuric acid is used as electrolyte.
When the battery is discharged, spongy lead is oxidized to lead ion (Pb2). The electrode plate is negatively charged. Pb2 and SO42- form PbSO4. To cover the electrode plate. And charging is just the inverse process of discharge. In the process of repeated charge and discharge, due to the continuous coverage and accumulation of PbSO4. The bonding, shrinkage and passivation of Pb particles will lead to the reduction of battery capacity. This is even more serious at low temperatures. In order to inhibit this passivation, BaSO4, carbon black, charcoal, cotton and other carbon-containing substances were often added to the cathode plate paste in the past. And lignosulfonate, tannin extract, synthetic tanning agent and humic acid were added as the plate “expansion agent” in the past 20 years.
300 cycle life tests at-18 ℃. The results show that using the weathered coal, the hard lignite and the weathered lignite humic acid as the expanding agent is the best. The service life of the battery is 30-50% higher than that of the peat humic acid. The storage of the battery with the humic acid as an expanding agent does not change the capacity index for 3 years. The practice has proved that, compared with other expanding agents, the humic acid can improve the capacity of the storage battery and the starting performance. Improve the working capacity of the cathode heat-insulating and unfreezing work. And prevent the active substances from passivating. Contracting and caking in the cyclic use. Saving the lead powder. Prolonging the service life and the like.