Introduction:
In today's era of environmental protection and technology, electric vehicles are becoming more and more popular and will completely replace traditional fuel vehicles in the future. The lithium battery is the heart of the electric vehicle, providing the required power for the electric vehicle to move forward. The service life and safety of electric vehicle batteries are the most concerned issues for car owners. However, these two issues are closely related to the correct charging method. The batteries used in electric vehicles now include ternary lithium batteries and lithium iron phosphate batteries. What effects will the two methods have on these two batteries? Let's discuss it together.
Impact of using up and then charging on ternary lithium batteries
1. Capacity decay: Each time the power of a ternary lithium battery is used up and then charged again, it is a deep discharge, which can cause the capacity of the ternary lithium battery to gradually decay, the charging time to shorten, and the driving range to decrease. For example, someone has done an experiment. After the ternary lithium battery is deeply discharged 100 times, the capacity decreases by 20%~30% compared with the initial value. This is because deep discharge causes damage to the electrode material, electrolyte decomposition, and metal lithium precipitation destroy the battery's charge and discharge performance, resulting in a decrease in capacity, and this damage is irreversible.
2. Shortened life: Deep discharge will accelerate the aging rate of the internal materials of the ternary lithium battery, reduce the battery's charge and discharge performance, reduce the number of cycle charge and discharge, and shorten the service life.
3. Reduced charge and discharge efficiency: Using up the power and then charging again will cause the positive and negative electrodes of the ternary lithium battery to polarize, increase the battery's internal resistance, reduce the charging efficiency, extend the charging time, reduce the battery capacity, and significantly reduce the amount of power that can be output.
4. Increased safety risks: Long-term deep discharge can cause the internal plates of the ternary lithium battery to deform or even break, resulting in a short circuit inside the battery and the risk of fire and explosion. In addition, deep discharge of the battery increases its internal resistance, reduces charging efficiency, and increases heat generation during charging, which can easily cause the ternary lithium battery to bulge and deform, and even cause thermal runaway, ultimately leading to explosion and fire.
Ternary lithium battery is the lightest and most energy-dense electric vehicle battery, and is generally used in high-end electric vehicles. In order to prevent the adverse effects of deep discharge on the battery, the battery is equipped with a protection board. The voltage of a fully charged single ternary lithium battery is about 4.2 volts. When the single voltage is discharged to 2.8 volts, the protection board will automatically cut off the power supply to prevent the battery from over-discharging.
The impact of charging as you go on ternary lithium batteries
The advantage of charging as you go is that the battery power belongs to shallow charging and shallow discharge, and always maintains a high power level to avoid the adverse effects of low power on the battery. In addition, shallow charging and shallow discharge can also maintain the activity of lithium ions inside the ternary lithium battery, effectively reduce the aging speed of the battery, and ensure that the battery can output power stably during subsequent use, and can also extend the battery life. Finally, charging as you go can ensure that the battery is always in a state of sufficient power and increase the driving range.
Impact of recharging after use on lithium iron phosphate batteries
Recharging after use is a deep discharge, which will also have adverse effects on the internal structure of lithium iron phosphate batteries, causing damage to the internal structural materials of the battery, accelerating battery aging, increasing internal resistance, reducing charging and discharging efficiency, and extending charging time. In addition, after deep discharge, the chemical reaction of the battery intensifies and the heat increases sharply. The heat generated is not dissipated in time, which can easily cause the lithium iron phosphate battery to bulge and deform. The bulging battery cannot continue to be used.
Impact of charging as you go on lithium iron phosphate
According to normal charging and discharging, lithium iron phosphate batteries can be charged and discharged more than 2,000 times. If charging as you go as needed is shallow charging and shallow discharging, the service life of lithium iron phosphate batteries can be extended to the maximum extent. For example, the lithium iron phosphate battery can be charged and discharged from 65% to 85% of the power, and the cycle charge and discharge life can reach more than 30,000 times. Because shallow discharge can maintain the vitality of the active substances inside the lithium iron phosphate battery, reduce the aging rate of the battery, and extend the battery life to the maximum extent.
The disadvantage is that the lithium iron phosphate battery has poor consistency. Frequent shallow charging and discharging may cause a large error in the voltage of the lithium iron phosphate battery cells. Long-term accumulation will cause the battery to deteriorate at one time. To put it simply, there is an error in the battery voltage between each cell. The error value exceeds the normal range, which will affect the performance, mileage and service life of the entire battery pack.
Conclusion
Through the above comparative analysis, the damage caused to the two batteries by charging after the battery power is used up is irreversible, and this method is not advisable. Charging as you use is relatively friendly to the battery, and the negative impact caused by the lithium battery is relatively small, but it is not the correct charging method. The following shares the correct charging method to increase the safety of battery use and extend the service life.
1. Avoid excessive discharge: When the electric car's power meter shows that the battery power is 20~30% remaining, after using the car in summer, go to the charging place to let the battery cool for 30 minutes to an hour before charging, which can avoid the battery charging temperature from being too high, and at the same time avoid the adverse effects of deep discharge on the battery.
2. Avoid overcharging: The battery power is 20~30% remaining. , It takes about 8~10 hours to fully charge. It is recommended that the power supply can be cut off when the power is charged to 90% according to the power meter display, because charging to 100% will increase the heat generation and the safety risk hazards will increase exponentially, so the power supply can be cut off when it is charged to 90% to avoid the adverse effects of the process on the battery. Lithium iron phosphate batteries can be charged to 100%, but it should be noted that the power supply should be cut off in time after being fully charged to avoid overcharging.
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Post time: Feb-07-2025