1. Irreversible sulfation
Irreversible sulfation, referred to as sulfation. When a lead-acid battery is discharged, both the positive and negative plates produce a compound, namely lead sulfate. Lead sulfate is a substance that is insoluble in water and non-conductive. Under normal circumstances , The lead sulfate crystals formed by the battery after discharge are relatively small. When charging, under the action of electricity, it is relatively easy to dissolve and reduce to lead. Coarse and hard crystals are formed, and it is difficult to reduce them to lead by ordinary methods, so it is called irreversible sulfation. Due to sulfation, on the one hand, it can prevent sulfuric acid from contacting with other active substances. Reaction: On the other hand, reducing the number of active substances, it can cause the battery to easily decline, and in severe cases, the battery life will be terminated.
2. Exfoliation of active substances
When we repair used batteries, some reddish-brown liquids flow out from the water injection holes after adding water to repair the batteries. It is the fallen active material. The reasons for the falling off of the active material have the following explanations: 1. The battery is affected by external forces, such as vibration , beat, etc. 2. α-PbO2.βPbO2 variant model. αPbO2 is the active material skeleton. When the battery is charging and discharging, a part of α-PbO2 is converted into β-PbO2, which leads to softening and shedding. 3. As the cycle progresses, the active The material is gradually crystallized from an amorphous state, that is, the crystallinity increases, the number of hydrated polymer chains decreases, the gel piezoresistance increases, the electrical contact between grains deteriorates, and the active material falls off. 4. It is also believed that with charging As the discharge continues, the active material forms several dense clumps. When there is insufficient connection between the clumps, the active material will fall off and the battery will fail.
3. The voltage of the battery
The potential difference between the positive and negative poles of the battery is called the voltage of the battery, which is generally measured with a multimeter. In the process of battery repair, its voltage has three manifestations: the first is called no-load voltage, also known as open circuit voltage, that is, the battery is not charged and then The battery voltage measured under no load: the second is called the load voltage, which is the battery voltage measured at a certain period of time during the battery discharge process. The third is called the online voltage, which is the battery measured at a certain moment during the charging process. It is of great significance to understand the three voltage measurement methods to determine whether the battery is open or short-circuited; the calculation of the internal resistance of the battery is of great significance.
4. Battery capacity
The capacity of the battery is an important indicator to measure the performance of the battery. It is generally expressed in ampere hours. The general term for discharge time (hours) and discharge current (amperes), that is, capacity = discharge time × discharge current. The actual capacity of the battery depends on The amount of active material in the battery and the utilization rate of active material. The amount of active material is more.
