Recycling Of Electric Vehicle Batteries
1. Irreversible sulfation
Irreversible sulfation, abbreviated as sulfation When the lead-acid battery is discharged, both the positive and negative plates will produce a combination, i.e. lead sulfate. Lead sulfate is a non-conductive material that is difficult to dissolve in water. Under normal circumstances, the lead sulfate crystal formed by the battery after discharge is relatively small. When charging, it is easier to dissolve and reduce to lead under the action of electricity. If it is used improperly, it will often be under charged, water lost, overdischarge, etc Lead sulfate will form a thick and hard crystal, and it is difficult to reduce it to lead by general methods, so it is called irreversible sulfation. Due to sulfation, on the one hand, it can prevent sulfuric acid from contacting and reacting with other active substances; on the other hand, it can reduce the amount of active substances, which can cause the battery to drop easily, and in serious cases, it will cause the battery to end its life
2. Shedding of active substance
When we repair used batteries, some batteries are repaired with water, and some reddish brown liquid flows out from the water injection hole That is, the falling off active substance. The reasons for the falling off of the active substance can be explained as follows: 1. The battery is affected by external forces, such as vibration and wrestling α— PbO2. β PbO2 variant model α PbO2 is the active material skeleton. When the battery is charged and discharged, a part of α— Conversion of PbO2 to β— PbO2 causes softening and shedding 3. With the circulation, the active material gradually crystallizes from the amorphous state, that is, the crystallinity increases, the number of hydrated polymer chains decreases, the piezoresistance of gel increases, the electrical contact between grains deteriorates, and the active material falls off 4. It is also believed that with the continuous charging and discharging, the active material forms a number of dense clusters. When there is insufficient connection between the clusters, the active material will fall off and the battery will fail
3. Battery voltage
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, the voltage has three forms: the first is no-load voltage, also known as open circuit voltage, which is the battery voltage measured when the battery is neither charged nor loaded; the second is load voltage, which is the battery voltage measured at a certain time during the battery discharge process The third is called on-line voltage, which is the voltage measured at a certain time during the charging process of the battery. Understanding the three voltage measurement methods is helpful to judge whether the battery is open or short circuited; The calculation of battery internal resistance is of great significance
4. Capacity of storage battery
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 of 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 more active material is.
