SOC estimation method and SOC estimation device based on cell characteristic curve

Abstract

The invention discloses an SOC estimation method and an SOC estimation device based on a cell characteristic curve, wherein the SOC estimation method and the SOC estimation device belong to the field of cell management and testing technology. The SOC estimation method comprises the steps of acquiring an initial cell state-of-charge, a cell capacity, a cell monomer voltage value, a cell monomer temperature value, a cell working current value and a cell sampling period; performing calculation for obtaining a first cell state-of-charge; when duration time in which the cell working current value is smaller than a current threshold is shorter than a time threshold, obtaining a second cell state-of-charge according to preset state-of-charge-open-circuit-voltage curves at different temperatures; calculating a difference between the first cell state-of-charge and the second cell state-of-charge, and calculating the absolute value of the difference, thereby obtaining the cell state-of-charge difference; and determining a relationship between the cell state-of-charge difference and a state-of-charge threshold for determining a final cell state-of-charge. The SOC estimation method and the SOC estimation device have advantages of satisfying a requirement for high SOC testing precision at different temperatures by means of a simple calculation process, realizing SOC estimation and correction, and ensuring convenient and feasible calculation method and wide application range.

Description

technical field [0001] The invention belongs to the technical field of battery management and testing, in particular to an SOC estimation method and device based on battery characteristic curves. Background technique [0002] In today's energy crisis and increasingly serious environmental pollution, electric vehicles have been used more and more widely due to their zero-pollution and high energy efficiency. For electric vehicles, the battery is the core component of its power source, and the battery management system plays an important role in observing the state of the battery and ensuring the safety of the battery. Among the state parameters of the battery, the battery state of charge (SOC) is usually used to measure the remaining capacity of the battery, the cruising range and the available energy of the battery. [0003] At present, SOC estimation methods mainly include ampere-hour integral method, open circuit voltage method, Kalman filter algorithm or its derivative a...

AI Technical Summary

Problems solved by technology

[0005] Most of the existing SOC estimation methods are based on battery cells and the calculation complexity is too high. The calculation speed of the microprocessor is high, and the algorithm convergence speed is slow, resulting in a large error in SOC calculation, which is difficult to meet the actual needs.

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