Cause analysis of lead-acid battery failure

The failure status and cause analysis of lead-acid batteries Lead-acid batteries have been invented for more than 100 years. At present, the applications of lead-acid batteries in the market are: ordinary, sealed, and maintenance-free. Because of their economical and practical advantages, lead-acid batteries are still widely used, accounting for more than 70% of the market, and are used in all walks of life. However, due to the nature, structure, materials, processing and maintenance of lead-acid batteries and other factors, according to statistics, the phenomenon of premature failure of lead-acid batteries and waste materials, more than 75% are due to lead-acid battery electrodes formed by irreversible lead sulfate salts. Plate lead, self-discharge, failure reasons and lost active materials, these three problems have been plagued by the difficult problems of the lead-acid battery industry, but they are definitely not a good way to solve these three problems. For example, the design life of ordinary lead-acid batteries is 2-3 years. In fact, they are usually only used for one year or less. The maintenance-free lead-acid batteries have a design life of 7 to 15 years. Shorter than the expected service life, resulting in energy waste and economic benefits. The basic structure and characteristics of lead-acid batteries The important outer shell of lead-acid batteries, the active and negative plates, separators, and electrolytes convert electrical energy into chemical electrical energy storage under the use of electric fields, and chemical electrical energy into DC power, and can be repeatedly charged and discharged. Several devices, the electrochemical reaction formula is: The above formula shows that the lead-acid battery system is a complex electrochemical reaction. The performance of the lead-acid battery depends on the combination of the active and negative plate manufacturing materials, the process environment, and the purity of the active material. The composition and use of the environment and maintenance have a very important impact. Second, the positive and negative plates (electrodes) of lead-acid batteries are important in the relationship between active materials and capacity 1. Therefore, the positive and negative plates of lead-acid battery capacity are important for the area of u200bu200bactive materials that can participate in electrochemical reactions. The relationship of mass here refers to the fact that surface active materials can participate in the actual reversible electrochemical reaction, rather than the geometric size of the area. When the electrolyte is added to the lead-acid battery, the positive and negative plates are immersed in the electrolyte (sulfuric acid), and part of the sulfuric acid in the electrolyte is absorbed by the positive and negative plates, and the surfaces of the positive and negative plates are filled with lead sulfate. Under the use of an electric field, dense lead dioxide is formed on the surface of the positive plate, and dense pure lead is formed on the surface of the negative plate. Therefore, in the traditional charging and discharging process, after the positive and negative electrode plates are controlled by lead dioxide and pure lead, and the positive and negative electrode plates form lead sulfate and discharged, the active material should be a fake, interchangeable ion structure pair Effective reaction of electrochemically active substances. The rated capacity of any type of lead-acid battery is manufactured in accordance with the standardized standards. Only when the capacity of the lead-acid battery is frequently charged should be less than 95% of the rated capacity, which explains the unqualified lead-acid battery, the reason is the manufacturing material, processing technology, The environment, product storage time is too long, and other reasons for the failure of active material aging 1. Slab vulcanization: The so-called vulcanization refers to the formation of irreversible lead sulfate alkalization on the positive and negative plates to form a layer of white coarse-crystalline lead sulfate. This kind of crystal is difficult to eliminate during normal charging. The degree of vulcanization has a lot to do with lead-acid battery capacity, vulcanization, the less the capacitance, until it is cancelled, many factors of the board, it is important that the lead-acid battery storage time is too long, because the board is with sulfuric acid The surface of the active material causes the lead sulfate on the surface of the active material to lose its ionization effect after aging. Lead-acid batteries are discharged when they are put into use. The battery was not charged in time after being discharged. The electrolyte density is too high or impure. Therefore, vulcanization is an important reason for the failure and waste of active materials. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: How to extend the service life of lithium batteries?