Analysis of factors affecting the life of lead-acid batteries

The depth of discharge is the extent to which the discharge starts and stops during use. 100% depth means to release the full capacity. The life of lead-acid batteries is greatly affected by the depth of discharge. The focus of design consideration is deep cycle use, shallow cycle use or floating charge use. If a shallow-cycle battery is used for deep-cycle use, the lead-acid battery will quickly fail. Because the positive active material lead dioxide itself is not well-bonded with each other, lead sulfate is generated during discharge, and returns to lead dioxide during charging. The molar volume of lead sulfate is larger than that of lead oxide, and the volume of the active material expands during discharge. If one mole of lead oxide is converted to one mole of lead sulfate, the volume increases by 95%. Such repeated contraction and expansion will gradually loosen the mutual bond between the lead dioxide particles and easily fall off. If only 20% of the active material of one mole of lead dioxide is discharged, the degree of contraction and expansion will be greatly reduced, and the destruction of binding force will become slower. Therefore, the deeper the discharge depth, the shorter the cycle life. 2. Overcharge level A large amount of gas is released during overcharge. At this time, the active material of the positive plate is impacted by the gas, and this impact will cause the active material to fall off; in addition, the positive grid alloy is also subject to severe anodic oxidation and corrosion, so the battery Overcharging will shorten the service life. 3. The influence of temperature The lifespan of lead-acid batteries increases with the increase of temperature. Between 10°C and 35°C, for every 1°C increase, about 5-6 cycles are added. Between 35°C and 45°C, each 1°C increase can extend the life by more than 25 cycles; above 50°C, The life span is reduced due to the loss of vulcanization capacity of the negative electrode. The battery life increases with increasing temperature within a certain temperature range because the capacity increases with increasing temperature. If the discharge capacity remains unchanged, the depth of discharge decreases when the temperature rises, and the solid life is prolonged. 4. The influence of sulfuric acid concentration. Although the increase in acid density is beneficial to the capacity of the positive plate, the self-discharge of the battery increases and the corrosion of the grid accelerates, which also promotes the loosening of lead dioxide. As the acid density is used in the battery The new addition, the cycle life decreases. 5. The influence of the discharge current density As the discharge current density increases, the life of the battery decreases, because under the conditions of high current density and high acid concentration, the positive lead dioxide is promoted to loosen and fall off. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: 18650 lithium battery is better than polymer battery