what is lifepo4 battery?
The lifepo4 battery or LFP battery, is a type of lifepo4 battery using lithium iron phosphate as the cathode material, and a graphitic carbon electrode with a metallic backing as the anode. lifepo4 battery offer lots of benefits compared to lead-acid batteries and other lithium batteries. For example, Longer life span, no maintenance, extremely safe, lightweight, improved discharge and charge efficiency.
how to build a lifepo4 battery pack?
The core problem solved by the assembly of 12V lifepo4 battery pack is the consistency of lithium cell, that is, the smaller the value of the difference in pressure, capacity and internal resistance of each cell, the better, so that the assembled 12V lifepo4 battery pack can play the best effect in terms of use efficiency and service life.
Lithium iron phosphate battery pack material customized lithium ion battery pack nominal voltage is generally known as 12.8V, some battery technicians called 12.8V lithium ion battery pack, of course, lithium iron phosphate 12V lithium ion battery customization technology requirements are more stringent, it uses 4 string battery structure, can 26650 lithium ion battery, Or 18650 lithium ion battery PACK customization through 4 series technology PACK processing assembly, and then made into lithium iron phosphate 12V lifepo4 battery customized products.
how to charge lifepo4 battery pack?
CCCV charging method is recommended for lithium iron phosphate battery pack, that is, constant current and constant voltage. Constant current is recommended at 0.3c. When the battery voltage reaches 3.65V, use 3.65V constant voltage to charge. When the charging current is lower than 0.1c (or 0.05c), stop charging, that is, the battery is fully charged. It is recommended not to charge at too high a voltage. After adjusting the voltage, ensure that the charging current is below 0.5C, which is good for the battery.
Generally, the upper charging voltage of lithium iron phosphate battery is 3.7-4V, and the lower discharging voltage is 2-2.5V. Considering the discharge capacity, discharge median voltage, charging time, percentage of constant current capacity and safety, the charging scheme of constant current and constant voltage is adopted. For lithium iron phosphate battery pack, the charging limit voltage is set at 3.55-3.70V. The recommended value ranges from 3.60 V to 3.65V. The lower discharge voltage ranges from 2.2V to 2.5V.
The charger of Lithium iron phosphate battery pack is different from ordinary lithium battery. The maximum termination voltage of a lithium battery is 4.2 VOLTS; The lithium iron phosphate battery pack is 3.65 volts. When the lithium iron phosphate battery pack is charged, it is the line connected by the balance charging plate. It is generally charged in series directly from both ends. The voltage of the charger is greater than the voltage of the battery pack. The voltage of each single cell is detected by row, which is equivalent to parallel regulator tubes. The charging voltage of the single cell will not exceed the regulator value, while other single cells continue to be charged through the regulator tube by bypass.
how to test lifepo4 battery?
Battery charging
Under the condition of 20℃ and 5℃, the battery is discharged with 1I3(A) current until the battery voltage reaches V, and left for 1h, and then charged with 1I3(A) constant current under the condition of 20℃±5℃. When the battery voltage reaches constant voltage, the battery is charged until the charging current drops to stop charging. After charging, let LH stand.
20℃ discharge capacity
A) The battery is charged according to the method.
B) The battery discharges at A current of 1I3 (A) at 20 ° C and 5 ° C until discharge terminates the voltage.
C) The current value and discharge time data of 1I3(A) are used to calculate the capacity (in meters).
D) If the calculated value is lower than the stated value, steps A) one C) may be repeated until greater than or equal to the stated value, allowing 5 times.
-20℃ discharge capacity
A) The battery is charged according to the method.
B) The battery is stored at -20℃ and 2℃ for 20h.
C) The battery discharges at A current of 1I3 (A) at -20℃ and 2℃ until the discharge terminates the voltage.
D) Use c) current value and discharge time data to calculate the capacity (measured) and express it as a percentage of discharge capacity at 20℃.
-40℃ discharge capacity
A) The battery is charged according to the method.
B) The battery is stored at -40℃ and 2℃ for 20h.
C) The battery discharges at A current of 1I3 (A) at -40℃ and 2℃ until the discharge terminates the voltage.
D) Use c) current value and discharge time data to calculate the capacity (measured) and express it as a percentage of discharge capacity at 20℃.
Cycle life
A) Then charge at 9I3 (a) constant current at 20℃±5℃ until the battery voltage reaches constant voltage and stops charging when the charging current drops to. After charging,let LH stand.
B) The battery is discharged at A current of 913(A) at A temperature of 20℃ and 2℃, and then let stand for l5min.
C) The battery is charged according to method A).
D) Battery repeat steps b) a c) a number of times.
E) Check capacity according to method. If the battery capacity is less than 92% of the rated capacity, terminate the test.
F) b) e) The number of times a step is repeated under specified conditions is the number of cycle lives.