Influencing Factors Of Lead-acid Battery Life

1. Depth of discharge
The depth of discharge is the extent to which the discharge starts to stop during use. 100% depth refers to the discharge of the full capacity. The life of lead-acid batteries is greatly affected by the depth of discharge. The focus of design considerations is deep cycle use, shallow cycle use or floating charge use. If the battery used in shallow cycle is used for deep cycle use, The lead-acid battery will fail quickly.
Because lead dioxide, the positive active material, is not firmly combined with each other, lead sulfate is generated during discharge, and it returns to lead dioxide during charge. 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%. Repeated shrinkage and expansion in this way will gradually loosen the bond between the lead dioxide particles and make them easy to fall off. If only 20% of the active material of one mole of lead dioxide is discharged, the degree of shrinkage and expansion will be greatly reduced, and the destruction of the binding force will be slow. Therefore, the deeper the discharge depth, the shorter its cycle life.
2. Degree of overcharge
When overcharging, a large amount of gas is precipitated. At this time, the active material of the positive plate is impacted by the gas, which will promote the shedding of the active material; in addition, the positive grid alloy is also subject to severe anodic oxidation and corrosion, so the battery will The application period is shortened.
3. The influence of temperature
Lead-acid battery life increases with temperature. Between 10°C and 35°C, every increase of 1°C will increase about 5-6 cycles; between 35°C and 45°C, every increase of 1°C can prolong the life of more than 25 cycles; The life of the negative electrode is reduced due to the loss of vulcanization capacity.
Battery life increases with temperature within a certain temperature range because capacity increases with temperature. If the discharge capacity remains the same, the discharge depth decreases when the temperature rises, and the solid life is prolonged.
4. The influence of sulfuric acid concentration
The increase of acid density is beneficial to the capacity of the positive plate, but the self-discharge of the battery increases, and the corrosion of the grid also accelerates, which also promotes the loosening of lead dioxide. With the increase of the acid density used in the battery, the cycle life decreases.
5. Influence of 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 lead dioxide of the positive electrode is promoted to loosen and fall off.