What affect the lifespan of the Lead acid battery?
1, depth of discharge
The depth of discharge is the extent to which discharge occurs during use. 100% depth refers to the release of full capacity. The life of lead-acid batteries is greatly affected by the depth of discharge. The design considerations are deep cycle use, shallow cycle use or float charge. If the battery used in shallow cycle is used for deep cycle, the lead-acid battery will quickly fail.
Because the positive electrode active material lead dioxide itself is not firmly bonded to each other, lead sulfate is formed during discharge, and it returns to lead dioxide upon charging. The molar volume of lead sulfate is larger than that of lead oxide, and the active material expands in volume during discharge. If one mole of lead oxide is converted to one mole of lead sulfate, the volume is increased by 95%. By repeatedly shrinking and expanding, the mutual bonding between the lead dioxide particles is gradually relaxed and easily peeled off. If only one mole of active material of lead dioxide is discharged, the degree of shrinkage and expansion is greatly reduced, and the breaking force is slowed down. Therefore, the deeper the depth of discharge, the shorter the cycle life will be.
2, the degree of overcharge
When overcharging, a large amount of gas is precipitated. At this time, the active material of the positive electrode plate is subjected to the impact of the gas, and the impact promotes the falling of the active material; in addition, the positive electrode grid alloy is also severely anodized and corroded, so the battery may be overcharged. The application period is shortened.
3, the impact of temperature
Lead acid battery life extends with increasing temperature. Between 10 °C and 35 °C, for every 1 °C increase, the increase is about 5~6 cycles. Between 35 °C and 45 °C, the life can be extended for more than 25 cycles for every 1 °C increase. The negative electrode has a loss in vulcanization capacity and a reduced life.
Battery life increases with increasing temperature over a range of temperatures because capacity increases with increasing temperature. If the discharge capacity does not change, the depth of discharge decreases as the temperature increases, and the solid life is prolonged.
4, the impact of sulfuric acid concentration
The increase in acid density is advantageous for the capacity of the positive electrode plate, but the self-discharge of the battery increases, the corrosion of the grid also accelerates, and the loosening of the lead dioxide is also promoted. As the acid density in the battery increases, the cycle life decreases.
5, the impact of discharge current density
As the discharge current density increases, the life of the battery decreases because the positive electrode dioxide is loosely detached under conditions of high current density and high acid concentration.