Battery Energy Estimation Using Mid Voltage and SOHR Correction
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Solution Overview
Problem
Existing methods for calculating battery available energy in battery energy storage systems are prone to errors due to inaccuracies in voltage and current sensors, leading to incorrect estimation of available energy, especially after long distances of travel.
Innovation Solution
A battery management apparatus and method that includes a battery state calculator, mid voltage calculator, remaining capacity calculator, and available energy calculator, which corrects resistance deterioration and calculates mid voltage and remaining capacity to accurately determine available energy using a correction coefficient and interpolation methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional calculation method using voltage and current sensors is used, then the calculation process is simple, but the measurement precision deteriorates due to sensor errors accumulating over time
Solution Approach 1:
The patent introduces mid voltage as an intermediary parameter to bridge the relationship between battery state of charge and available energy. Instead of directly integrating sensor measurements, the system calculates mid voltage based on battery characteristics and uses it to compute available energy, thereby eliminating the accumulation of sensor errors while maintaining calculation simplicity
Solution Approach 2:
The patent changes the calculation parameters from direct sensor-based integration to a method using mid voltage and battery capacity. By transforming the calculation approach to use parameters that can be more accurately determined from battery characteristics rather than accumulated sensor data, the system improves measurement precision without significantly increasing device complexity
2Ease of operation
If battery available energy is calculated using accumulative consumption energy method, then the calculation is straightforward, but the reliability deteriorates after long distance travel due to error accumulation
Solution Approach 1:
The patent performs preliminary calculation of mid voltage and remaining capacity before computing available energy. By pre-determining these key parameters based on battery state of charge and capacity deterioration degree, the system establishes a reliable foundation for available energy calculation that does not depend on accumulative sensor measurements, thereby maintaining ease of operation while improving reliability
Solution Approach 2:
The patent incorporates feedback mechanisms by continuously monitoring battery state of charge and capacity deterioration degree, and using this information to adjust mid voltage and remaining capacity calculations. This feedback loop ensures that available energy estimates remain reliable even after long distance travel, as the system constantly updates based on actual battery condition rather than relying solely on accumulative consumption data
Data Source
AI summary
A battery management apparatus 102 calculates a state of charge SOC representing the state of charge of a chargeable and dischargeable battery, a charge deterioration degree SOHQ and a resistance deterioration degree SOHR, corrects the calculated SOHR, corrects an mid resistance MidDCR corresponding to a mid voltage MidVoltage according to a correction coefficient in accordance with SOHR for MidDCR (corrected SOHR), calculates MidVoltage (a mid voltage present between a discharge voltage in the current state of charge of the battery, and a voltage value representing a discharge voltage in the minimum state of charge of the battery), calculates the remaining capacity of the battery based on SOC and SOHQ, and calculates the available energy of the battery based on the mid voltage and the remaining capacity.