Discharge characteristics are different from those of electric vehicles
Currently, the lithium iron phosphate cells used in many household energy storage batteries actually adopt automotive cell production standards, but in practice there are significant differences from electric vehicles. Discharge in electric vehicles is actually a small-rate, basically constant-power discharge. For example, if a car is fully charged and runs 400KM, it will take 4 hours to completely discharge the electricity at an average speed of 100KM/H, which is equivalent to a 0.25C discharge rate; while in home storage Depending on the load power, usage environment, etc., the battery may be discharged as short as 1 hour or as long as 10 hours, which is equivalent to a discharge rate ranging from 0.1C to 1C. Rapid discharge at high rates has a great impact on battery heating. If the design is unreasonable and the temperature difference in the battery pack is too large, it will greatly aggravate the dynamic consistency of lithium iron phosphate and shorten its service life.
In actual use, household energy storage batteries vary depending on the electricity usage scenario.
Many times it is in a shallow charge and discharge state, that is, it is in a state where the discharge voltage of lithium iron phosphate is stable. In the current management of lithium iron phosphate batteries, its key parameter SOC (State of Charge) needs to be calibrated to high potential and low potential before it can be accurately judged. However, if the high potential or low potential is not reached during shallow charging and discharging, Calibrating the voltage will cause the cumulative error of the SOC to become larger and larger, causing misjudgments in the system and affecting the actual use of home energy storage batteries. In addition to improving the accuracy of the algorithm, the solution can be through mandatory calibration. Of course, the positioning and maintenance of energy storage batteries is also particularly important.
Post time: May-24-2024
