26650 battery LiFePO4 3.2V 3200mAh for solar street light
Specification of 26650 battery
0.5C,( current value of 3200mA at 1C）
Alternating Internal Resistance
constant-current charge to 3.65V at 0.5C,constant voltage charge to stop until 0.01C mA
Max. Charging Current
Discharge Cut-off Voltage
Standard Discharge Current
Fast Discharge Current
Max. Continuous Discharge Current
Pulse Discharge Current
the residual capacity is no less than 80% of rated capacity at 1C rate.
-20°C ~ 45°C
Short-term storage (< 3 months)
Structure and working principle
LiFePO4 is used as the positive electrode of the battery. It is connected to the positive electrode of the battery by aluminum foil. The middle is a polymer separator. It separates the positive electrode from the negative electrode, but the lithium ion Li can pass and the electron e- cannot pass. The right side is composed of carbon (graphite). The negative electrode of the battery is connected by a copper foil to the negative electrode of the battery. Between the upper and lower ends of the battery is the electrolyte of the battery, and the battery is hermetically sealed by a metal casing.
When the LiFePO4 battery is charged, the lithium ion Li in the positive electrode migrates toward the negative electrode through the polymer separator; during the discharge, the lithium ion Li in the negative electrode migrates toward the positive electrode through the separator. Lithium-ion batteries are named after the lithium ions migrate back and forth during charging and discharging.
The nominal voltage of the LiFePO4 battery is 3.2V, the termination charging voltage is 3.6V, and the termination discharge voltage is 2.0V. Due to the quality and process of the positive and negative materials and electrolyte materials used by various manufacturers, there will be some differences in their performance. For example, the same model (standard battery of the same package) has a large difference in battery capacity (10% to 20%).
It should be noted here that lithium iron phosphate power batteries produced by different factories may have some differences in various performance parameters; in addition, some battery performances are not included, such as battery internal resistance, self-discharge rate, charge and discharge temperature, and the like.
Lithium iron phosphate power batteries have large differences in capacity and can be divided into three categories: small fractions to a few milliamperes, medium tens of milliampere hours, and large hundreds of milliampere hours. There are some differences in the same parameters for different types of batteries.
Overdischarge to zero voltage test:
The STL18650 (1100mAh) lithium iron phosphate power battery was used for over-discharge to zero voltage test. Test conditions: A 1100 mAh STL 18650 battery was charged at a charging rate of 0.5 C, and then discharged at a discharge rate of 1.0 C until the battery voltage was 0 C. The batteries placed in 0V are divided into two groups: one group is stored for 7 days, and the other group is stored for 30 days; after the storage expires, it is filled with a charging rate of 0.5 C, and then discharged with 1.0 C. Finally, compare the differences between the two zero voltage storage periods.
The result of the test is that the battery has no leakage after 7 days of zero voltage storage, and the performance is good, the capacity is 100%; after 30 days of storage, there is no leakage, the performance is good, the capacity is 98%; after 30 days of storage, the battery is further charged and discharged for 3 times. The capacity is restored to 100%.
This test shows that even if the lithium iron phosphate battery is over-discharged (even to 0V) and stored for a certain period of time, the battery will not leak or be damaged. This is a characteristic that other types of lithium-ion batteries do not have.