Use and Maintenance of Batteries for Electric Vehicles

1. Avoiding Overdischarge
After the battery discharges to the termination voltage, the continued discharge is called overdischarge.
Overdischarge can seriously damage the battery, which is very harmful to the electrical performance and cycle life of the battery.
When the battery is discharged to the termination voltage, the internal resistance is larger, the concentration of electrolyte is very thin, especially the inner and outer surface of the plate is almost neutral. When the overdischarge occurs, the internal resistance tends to heat, the volume shrinks, and when the discharge current is larger, the obvious heating (or even heating deformation) occurs. At this time, the concentration is particularly high, and the possibility of short circuit of dendrite crystal increases, and at this time, the dendrite crystal will crystallize into larger particles. Granules, which constitute irreversible salinization, will further increase the internal resistance, so that charging recovery is poor and can not be repaired.
Overdischarge should be avoided in battery operation, and undervoltage maintenance is an effective measure. In addition, because the "under-voltage maintenance" of electric vehicles is controlled by the controller, but some other devices such as voltmeters, indicator lights and other power-consuming appliances outside the controller are directly powered by batteries. The supply of power is generally not controlled by the controller. Once the locks (switches) of electric vehicles are closed, they start to use electricity. Although the current is small, if the discharge lasts for a long time (1-2 weeks), it will show overdischarge. Therefore, the lock should not be unlocked for a long time and should be switched off immediately when not in use.
2. Avoid Overcharging
Previously, the overcharge will increase the water loss of the battery, accelerate grid corrosion, soften the active material, and increase the probability of battery deformation. Overcharging should be prevented as far as possible; the selection of charger parameters should be well matched with batteries, and the operation of batteries at high temperature should be fully understood, as well as the change of the whole service life. Do not put the battery in the overheated environment when using, especially when charging, keep away from the heat source. After the battery is heated, cooling measures should be taken to stop charging until the temperature of the battery returns to normal. The location of the battery device should ensure good heat dissipation as far as possible. When overheating is found, charging should be stopped and the charger and battery should be checked. The charging time should be shortened when the discharge depth of the battery is shallow or the ambient temperature is high.
3. Avoiding Short Circuit
When the battery is in short-circuit state, its short-circuit current can reach hundreds of amperes. The stronger the short-circuit contact is, the larger the short-circuit current is. Therefore, a large amount of heat will be generated in all joints, and the more heat will be generated in the thin links, which will fuse the joints and produce short-circuit phenomenon. Explosive gases (or explosive gases accumulated during charging) may be produced in the battery part, which will cause the battery explosion when fusing at the junction; if the short circuit time of the battery is short or the current is not particularly large, it may not cause the fusing phenomenon at the junction, but the short circuit will still cause overheating, which will damage the adhesive around the junction bar, leaving hidden dangers such as leakage. Therefore, the battery must not be short-circuited. Special care should be taken when installing or using the battery. Insulation measures should be taken. When connecting, electrical appliances other than the battery should be connected well. After checking, there is no short-circuiting. Finally, the battery should be connected. The wiring standard should be well insulated so as to avoid the collapse of stack under pressure.
4. Avoid loosening and insecurity of cohesion
If the contact is not firm and the level is relatively light, the conductivity will be poor, which will make the contact part of the line heated, the line loss is large, the output voltage is low, which will affect the motor power, reduce the driving mileage or can not ride normally; if the contact of the terminal components is not firm (most of the faults are at the junction and the junction), the terminal will generate a lot of heat, affecting the terminal and sealant. Separation, a long time will occur leakage phenomenon. If contact is not strong during driving or charging, circuit breaking may occur, and fierce sparks may occur when circuit breaking, which may ignite the explosive gases inside the battery (especially the battery which is just charged, because there are more explosive gases in the battery, and the battery has enough electricity, the sparks are fierce when circuit breaking, and the possibility of explosion is quite large).
Electric vehicles should accept more intense vibration in operation. Therefore, the reliability of all joints should be checked. Connectors should have "self-locking" function to avoid vibration and pulling scatter. Connections with batteries should be connected by connectors and soldered firmly by soldering tin. Connectors and connections should be pressed together (or soldered once again with solder to increase the reliability). )
5. Avoid sun exposure
Increased activity of active substances affects the service life of batteries