Method for calibrating static SOC by SOC-OCV curve of lithium iron phosphate battery

Abstract

The invention discloses a method for calibrating static SOC by SOC-OCV curve of a lithium iron phosphate battery. The method comprises the following steps: 1, setting different temperatures, respectively sampling at least two batteries in parallel at different temperatures, and calibrating a reference capacity; 2, OCV testing; 3, repeating the steps 1 to 2, and testing to obtain SOC-OCV curves at all temperatures; 4, calibrating the SOC according to an algorithm; and 5, carrying out SOC calibration according to conditions and logic: 1) calibration is carried out immediately in a non-voltage platform area; (2) in a voltage platform area, if the difference between the target SOC value and the current SOC value is within 10%, calibration is not carried out; and 3) in the voltage platform area, when the difference between the target SOC value and the current SOC value is more than 10%, calibration is carried out immediately. According to the method, under the steady-state voltage after standing, the SOC is calibrated according to the measured SOC-OCV curve, the error range is reduced, and the estimation precision of the SOC is effectively improved.

Description

technical field [0001] The invention belongs to the technical field of lithium iron phosphate batteries, and in particular relates to a method for calibrating the static SOC by the SOC-OCV curve of the lithium iron phosphate battery. Background technique [0002] Lithium-ion batteries have the advantages of long cycle life, high specific energy, no memory effect, and good environmental compatibility. As a new energy industry, lithium-ion batteries are showing a trend of rapid development. Compared with transition metal oxide cathode materials, LiFePO4 with olivine structure has the advantages of long cycle life, good safety and low cost, and has a wide range of applications in electric vehicles, communication energy storage and other fields. During the use of the battery, the estimation of the SOC (state of charge) of the battery is an extremely important indicator. Whether the SOC estimation is accurate or not will directly affect the decision-making of the battery manageme...

AI Technical Summary

Problems solved by technology

However, since the lithium iron phosphate battery has a long charge-discharge platform range, when the battery is fully static, if the voltage of the single cell is within the range of the platform range, accurate SOC correction cannot be performed, and the estimation error of the battery SOC is relatively large.

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