Why E-bike 48V/20AH LiFePO4 Battery Pack Life Shortern?

- Feb 02, 2019 -

Why E-bike 48V/20AH LiFePO4 Battery Pack Life Shortern?


Phenomenon:


People who have used 48V/20AH lithium iron phosphate battery pack for electric bicycle will find that although the service life of lithium iron phosphate battery pack is as long as 2000 times, its attenuation is also serious. After one month of use, the riding distance decreases rapidly from 45 km to less than 10 km. Why is that?


Reason analysis:

Although the battery has a balancing protection board, the effect of this balancing is very limited. The principle of the current balanced protection board for lithium batteries is that after discharging the batteries with over-set voltage and reaching the set voltage, the charging circuit is turned on to charge the whole batteries, so that the "backward" batteries have the opportunity to reach the same voltage as other batteries. However, the discharge current can not be very large, otherwise the calorific value and device life become a problem.


Explain in detail:

When charging, when the voltage of any group of batteries in the battery pack reaches 3.7V, the protective board cuts off the charging circuit to prevent the battery from overcharging; when discharging, when the voltage of any group of batteries in the battery is less than 2.5V, the protective board cuts off the external power supply to prevent the battery from overcharging. When the battery voltage of the corresponding group is higher than 3.5V, the protective plate begins to balance. This is mainly because the inconsistency of lithium-iron batteries is serious. In the long-term use, the voltage of the batteries is gradually lower than that of other batteries, and the battery is not well balanced during normal charging (the original lead-acid batteries were discarded due to overcharging, and later the charging time was set for each charging), which results in the voltage of the batteries being lower and lower than that of other batteries (the capacity is much lower than that of other batteries). He group. In this way, in use, the protection panel will cut off the power supply of the whole battery group to protect the battery because the group of batteries first reaches the undervoltage protection threshold of 2.5V. According to the barrel principle, the capacity of the whole battery pack depends on the lowest battery pack. When charging, because the capacity and voltage of other batteries are much higher than those of low-voltage batteries, when the capacity of low-voltage batteries is far from full, the voltage of other batteries has reached the turn-off voltage of the protective board, so the charging of the whole batteries is cut off. Such a vicious cycle, resulting in low-voltage packs not charged, resulting in the capacity of the whole battery pack is getting lower and lower, which is reflected in the use of shorter and shorter riding distance.


What does SINOLI battery do?

therfore, SINOLI battery is endeavor in not only supply good quality battery cell, but also making great efforts to provide customer with new type of balance protective battery management board.