Research On Deterioration Mechanism And Activation Technology Of Lead-acid Battery Under Substation Operating Conditions

With the development of society and technological progress,the problem of energy shortage is becoming more and more serious,and the development of largescale energy storage technology has gradually attracted people’s attention.As an electrical energy storage device,the battery is also a hot topic among them.Lead-acid batteries are active in various scenarios because of their large storage capacity,high cost performance,and good stability.The most common ones include: communications,railways,electricity,medical care,and automobiles.Due to the above-mentioned wide range of applications,lead-acid batteries currently have a broad market in my country.In the power industry,lead-acid batteries are widely used in substations.As the main component of the DC system,lead-acid batteries are very important in the safe operation of substations.However,due to the unique operating conditions and maintenance plans of substations,lead-acid batteries often fail to reach the designed service life and are retired in advance.Scrap lead-acid batteries are considered hazardous waste,posing a great threat to environmental safety and personal health.In this paper,according to the structure and unique working conditions of lead-acid batteries in substations,the influencing factors of the working life of lead-acid batteries in substations are summarized,and the causes and mechanisms of deterioration and failure of substation returned lead-acid batteries are explored.Through the electrical parameter test,anatomical test and microstructure analysis of the batteries returned from the substation,the typical failure modes of the lead-acid battery under the operating conditions of the substation are summarized: corrosion of the positive grid,sulfation of the negative electrode and drying of the electrolyte.Based on the typical failure mode under the operating conditions of the substation,the activation repair technology of the retired battery is studied.Remove the irreparable physical damage of positive grid corrosion,aming at the two failure modes of sulfation of the negative electrode and drying of the electrolyte,carried out activation repair exploration.A comprehensive activation technology based on chemical reagent method and physical charging method is selected.Firstly,the electrochemical experiments of lead electrodes in sulfuric acid electrolyte were carried out,and cyclic voltammetry was used to explore the electrochemical characteristics and charge-discharge laws of the negative electrode of the battery.Based on the chemical repair method,the activating reagent was added to the electrolyte,and the chemical reagents that improved the charge and discharge capacity of the negative electrode of the battery were screened out,and by orthogonal test,two kinds of compound activation reagents with the best effect were selected.Finally,the activation value of the substation decommissioned batteries was evaluated,the batteries with lower repair value were excluded,and two activators with similar effects were added to the substation decommissioned batteries,at the same time,a segmented charge current was applied for activation.The results show that the activator has different repairing effects on batteries with different degrees of deterioration.The battery with a remaining capacity of more than 60% has the best effect,and the capacity after repair can reach about 80%,which can be put into secondary use.Exploring the failure mechanism and activation repair technology of lead-acid batteries in substations can not only improve the operation and maintenance plan of substations,ensure the safe operation of substations,but also prolong the remaining life of deteriorated lead-acid batteries,which will help to build a "resourcesaving and environment-friendly" society.It is of great significance to the economic benefits of the power grid and even the safety of the social environment.