Lithium iron phosphate batteries are subject to temperature.18650 battery 4800mah

　　At temperatures ranging from 0 to -20 ℃, the discharge capacity of lithium iron phosphate batteries is equivalent to 88.05%, 65.52%, and 38.88% of the capacitance at 25 ℃, respectively; The average discharge voltage is 3.134, 2.963V, and 2.788V, respectively. The average discharge voltage at 20 ℃ is 0.431V lower than at 25 ℃. From the above analysis, it can be seen that as the temperature decreases, the average discharge voltage and discharge capacity of lithium-ion batteries both decrease, especially when the temperature is -20 ℃, the discharge capacity and average discharge voltage of the battery decrease rapidly.

　　Low temperature has an impact on the positive and negative electrodes, electrolyte, and adhesive of lithium iron phosphate batteries. For example, the positive electrode of lithium iron phosphate batteries has poor electronic conductivity and is prone to polarization in low temperature environments, thereby reducing battery capacity; Due to the influence of low temperature, the speed of lithium intercalation in graphite decreases, making it easy for metallic lithium to precipitate on the surface of the negative electrode. If it is put into use due to insufficient storage time after charging, metallic lithium cannot be fully embedded inside the graphite again. Some metallic lithium continues to exist on the surface of the negative electrode, which is highly likely to form lithium dendrites, affecting battery safety.

　　At low temperatures, the viscosity of the electrolyte will increase, and the migration impedance of lithium ions will also increase accordingly; In addition, the adhesive is also a crucial factor in the production process of lithium iron phosphate batteries, and low temperatures can have a significant impact on the performance of the adhesive.

　　Moreover, during low-temperature charging of lithium iron phosphate batteries, lithium ions may not have enough time to embed into the graphite negative electrode, resulting in the precipitation of metal lithium dendrites on the surface of the negative electrode. This reaction will consume the lithium ions in the battery that can be repeatedly charged and discharged, and significantly reduce the battery capacity. The precipitated metal lithium dendrites may also puncture the separator, thereby affecting safety performance.

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