Battery Capacity Estimation Using Voltage-Charge Correlation Updates
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Solution Overview
Problem
Aged batteries from electric vehicles exhibit varying performance rates due to different usage conditions, leading to reduced battery pack capacity and increased risks of overcharging or overdischarging, making it difficult to effectively assess their capacity for secondary applications as mobile power sources.
Innovation Solution
A method that determines battery capacity by measuring voltage and electric charge changes, updating correlation data, and calculating correction voltages to accurately estimate battery capacity, even for aging batteries, using a device with a processor and memory to execute the estimation method and store correlation data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If aged batteries are used as mobile power sources, then they can extend service life and reduce waste, but their capacity assessment becomes unreliable due to varying aging rates and historical data limitations
Solution Approach 1:
The patent changes the assessment parameters from relying solely on historical data to using real-time voltage-charge correlation data. By measuring voltage at different charge states and establishing empirical correlation curves, the system adapts to each battery's actual aging characteristics rather than using generic historical assumptions, thereby maintaining measurement precision for aged batteries
Solution Approach 2:
The system implements feedback by continuously measuring voltage-charge relationships and updating capacity assessments based on actual performance data. The correlation data between voltage and charge is used to refine capacity estimates, creating a closed-loop assessment mechanism that compensates for aging effects and varying usage conditions
2Quantity of substance
If batteries with large performance differences are assembled into packs, then voltage and capacity can be increased, but the total capacity is reduced and overcharging/overdischarging risks increase
Solution Approach 1:
The patent segments the battery pack assessment into individual cell-level voltage-charge measurements rather than treating the pack as a single unit. By establishing separate correlation data for each battery's voltage-charge relationship, the system can independently monitor and assess each cell's state, enabling precise tracking of batteries with different performance characteristics within the same pack
Solution Approach 2:
The system applies local quality by tailoring the capacity assessment to each individual battery's actual characteristics through its specific voltage-charge correlation data. Rather than using a uniform assessment method for all batteries in the pack, the patent customizes the evaluation based on each battery's unique aging pattern and performance profile, thereby accurately determining the pack's total usable capacity while preventing overcharging or overdischarging of individual cells
3Device complexity
If traditional historical data methods are used for capacity assessment, then the process is simple, but it becomes impossible to effectively assess batteries aging too quickly
Solution Approach 1:
The patent performs preliminary action by pre-establishing voltage-charge correlation data for each battery before capacity assessment is needed. The system proactively builds and stores the relationship between voltage and charge states through controlled charging/discharging cycles, creating a reference database that enables rapid and accurate capacity assessment without requiring complex real-time calculations when the battery is in use
Solution Approach 2:
The patent replaces the mechanical/historical data-based assessment system with an electrical measurement-based system. Instead of relying on chronological historical records and manual tracking, the invention uses electrical voltage measurements combined with charge calculations to directly determine capacity, providing a more responsive and accurate method that works effectively even for rapidly aging batteries
Data Source
AI summary
A method for estimating a battery capacity includes: determining the measurement voltage of the battery before charging or discharging, the electric charge change of the battery during charging or discharging and the measurement voltage the battery after charging or discharging; Obtaining the correlation data between the voltage and the electric charge of the battery; Updating the correlation data according to the measurement voltage of the battery before charging or discharging, the measurement voltage of the battery after charging or discharging, the electric charge change, and the correlation data; and determining the battery capacity according to the updated correlation data. The invention can update the correlation data between the voltage and charge of the battery and in turn determine the battery capacity, so that the battery capacity can be determined precisely in the course of its life cycle even as the battery ages.