Battery SOC Calculation Under Rapid Temperature Change
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Solution Overview
Problem
Existing methods for calculating the state of charge (SOC) of a battery are inaccurate when the battery temperature changes rapidly, leading to a discrepancy between calculated and actually available SOC.
Innovation Solution
A method that calculates the SOC of a battery by obtaining its temperature and determining a specific SOC associated with a discharge endpoint based on a plurality of temperatures calculated for gradually downgraded SOCs, thereby adjusting the SOC change trend to reflect actual battery conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the SOC is calculated based on voltage change and lookup table, then the calculation method is simple, but the accuracy deteriorates when temperature changes rapidly
Solution Approach 1:
The patent changes the parameter basis for SOC calculation from simple voltage lookup to a comprehensive model incorporating temperature, current, and time parameters. The SOC is calculated using the formula: SOC(t) = SOC(t-Δt) + (I × Δt) / Q - η(I, T) × Δt, where temperature T and efficiency η are dynamically adjusted parameters that improve accuracy under varying thermal conditions.
Solution Approach 2:
The patent performs preliminary temperature prediction and efficiency correction before final SOC calculation. By predicting future temperature trends and pre-calculating efficiency factors based on current temperature and current rate, the system compensates for thermal effects before they significantly impact the SOC measurement, thereby maintaining accuracy during rapid temperature changes.
2Measurement precision
If temperature compensation is added to improve SOC accuracy, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent segments the SOC calculation into distinct functional modules: voltage measurement module, temperature measurement module, current measurement module, efficiency calculation module, and SOC integration module. Each module handles a specific aspect of the calculation, making the complex system more manageable and allowing for independent optimization of each component without overwhelming system-level complexity.
Data Source
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AI summary
A method of calculating a state of charge of a battery, includes: calculating, by at least one processor, a state of charge (SOC) of a battery; obtaining, by the at least one processor, a temperature of the battery; calculating, by the at least one processor, based on the obtained temperature, a plurality of temperatures associated with a plurality of SOCs of the battery that are gradually downgraded from the calculated SOC of the battery by a grade; determining, by the at least one processor, based on the calculated plurality of temperatures, a specific SOC associated with a discharge end point of the battery; and determining, by the at least one processor, based on the determined specific SOC, a change trend of the SOC of the battery.