Power Battery Energy Estimation Using Cell Segmentation
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Solution Overview
Problem
Current methods for estimating the remaining available energy of a power battery in electric vehicles are inaccurate due to factors like sampling errors, neglect of battery temperature and discharge conditions, and inconsistencies in cell capabilities, leading to unreliable travel range predictions.
Innovation Solution
A method and device that estimate the remaining available energy by calculating the maximum available energy of cells with minimum State of Charge (SOC) and maximum capability, considering the number of cells and their SOC imbalance, using equations that integrate charging voltage and current, and accounting for battery temperature and aging, to provide a more accurate estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to estimate remaining available energy, then the estimation process is simple, but the accuracy of travel range prediction is poor
Solution Approach 1:
The patent segments the battery system into individual cells and further into key characteristics (minimum SOC cells, minimum capability cells). By analyzing these segmented subsets rather than treating all cells uniformly, the method achieves more accurate estimation of remaining available energy while managing computational complexity through focused analysis of critical cell groups.
Solution Approach 2:
The patent applies local quality by identifying and separately analyzing cells with specific local characteristics (minimum SOC, minimum capability) rather than applying a uniform estimation approach to all cells. This localized analysis of critical cell subsets improves overall estimation accuracy by focusing computational resources on the cells that most constrain the battery pack's remaining energy.
2Reliability
If cell inconsistencies are not considered, then the estimation method is straightforward, but the reliability of energy prediction is poor
Solution Approach 1:
The patent segments the battery cells into distinct groups based on their characteristics (minimum SOC cells, minimum capability cells). This segmentation allows the system to account for cell inconsistencies by analyzing each segment's specific properties, thereby improving prediction reliability while managing complexity through structured categorization rather than exhaustive individual cell analysis.
Solution Approach 2:
The patent recognizes that different cells have different local qualities (SOC levels, capability characteristics) and analyzes these local variations by identifying cells with minimum values in each category. This approach improves reliability by accounting for the most constraining cells while avoiding the complexity of analyzing every cell's full profile in detail.
3Measurement precision
If temperature and discharge conditions are ignored, then the estimation process is faster, but the accuracy of remaining energy calculation is poor
Solution Approach 1:
The patent segments the analysis to focus on critical parameters (minimum SOC, minimum capability) rather than computing full profiles for all cells under all conditions. This segmented approach incorporates temperature and discharge condition effects through the identified key characteristics, achieving accurate estimation while reducing computation time by avoiding exhaustive analysis of all cells and all parameters.
Data Source
AI summary
A method and device for estimating remaining available energy of a power battery is provided. The method includes: estimating, under current state, maximum available energy of a first cell with minimum State of Charge (SOC), and maximum available energy of a second cell with minimum of maximum available capability in the power battery; estimating remaining available energy of the first cell based on its maximum available energy and SOC, and estimating remaining available energy of the second cell based on its maximum available energy and SOC; and estimating the remaining available energy of the power battery based on the number of cells included in the power battery and the smaller one of the remaining available energy between the first and the second cell.