Research On Negative Bus-bar Corrosion Of Valve Regulated Lead Acid Batter

Valve-regulated lead-acid batteries are widely used in various fields of production and life due to their mature technology,stable performance,low price and easy maintenance.Since the characteristics of the negative bus-bar corrosion failure are not obvious and difficult to predict,once negative bus-bar corrosion occurs,it may cause very serious consequences.Through the research on the corrosion mechanism of the negative bus-bar,the corrosion-resistant alloy and the negative bus-bar production process,the corrosion resistance of the negative bus-bar is improved,and the significant failure mode of the negative bus-bar corrosion is transformed into a non-significant failure mode,ensure the safe use of valve-regulated lead-acid batteries.Using VRLA batteries that are replaced in the floating state until they are replaced by the warranty period.,the corrosion of the negative bus-bar is analyzed,and the corrosion law of the negative bus-bar in the battery is studied and verified: the thickness of the corrosion layer from the plate ear to the bus-bar is changed to the upper part of the bus-bar>the lower part of the bus-bar >plate ear.The linear sweep voltammetry tests of two lead alloy electrodes at 25 °C and 60 °C were carried out to study the effect of hydrogen evolution rate on the surface of t he alloy on the H+ concentration in the alloy liquid film,further affecting the position of the maximum thickness corrosion region of the negative electrode alloy and the thickness of corrosion layer.Through the accelerated corrosion test of lead-bismuth alloy,lead-tin alloy,modified lead-tin-selenium alloy spline and negative bus-bar,it is found that the corrosion resistance of the negative bus-bar alloy is closely related to its grain structure.The improved lead-tin alloy has a small grain size and superior corrosion resistance.60 °C 2.25 V constant voltage floating charge for 2 months,55 °C,2.25 V constant voltage floating charge for 6 months,the average corrosion layer thickness of lead-bismuth alloy,lead-tin alloy and modified lead-tin selenium alloy are: 280 ?m,213 ?m and 93 ?m.Through the negative bus-bar welding test,the reason for the corrosion cracking of the negative bus-bar alloy with good corrosion resistance is the crevice corrosion.The gap mainly occurs between the bus-bar and the plate ear,the bus-bar and the pole welding;the gap in the negative bus-bar is mainly caused by the artificial welding method,the bus-bar welding mold design,the welding torch size,the welding torch flame size and other factors.Influence,through th e study of the factors affecting the gap found a way to avoid the occurrence of welding gaps.In order to further improve the corrosion resistance of the nagative busbar,the entire bus-bar is wrapped with sealant to achieve isolation of the bus-bar from oxygen,which can reduce the bus-bar corrosion rate by 50% compared with the normal case.