Battery Availability Assessment Using Open-Circuit Voltage Curves
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Solution Overview
Problem
Secondary batteries are often discarded prematurely due to simplistic determination methods based on State of Health (SOH), leading to potential usable batteries being discarded, which negatively impacts energy efficiency.
Innovation Solution
An availability determination apparatus and method that acquires open circuit potential curves, calculates shrinkage rates for each electrode, and determines upper and lower limit voltages to assess the use availability of deteriorated secondary batteries at both low and high load times, reducing the likelihood of discarding usable batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a simple SOH-based determination method is used, then the determination process is simple and fast, but usable deteriorated batteries are discarded
Solution Approach 1:
The determination process is segmented into multiple evaluation dimensions: low-load time availability assessment and high-load time availability assessment. Each dimension uses different calculation methods (open circuit potential curve deformation for low-load, corrected curve with voltage drop for high-load), allowing comprehensive evaluation without excessive complexity in any single step.
Solution Approach 2:
The invention changes the assessment parameters from a single SOH value to multiple parameters including open circuit potential curves, shrinkage rates, upper/lower limit voltages, and capacity values. These parameter changes enable more accurate differentiation between truly deteriorated batteries and those with remaining usability.
2Reliability
If a comprehensive availability determination is performed, then battery usability is accurately assessed, but the determination process becomes complex
Solution Approach 1:
The invention applies different determination dynamics based on load conditions. For low-load times, it uses open circuit potential curve deformation with shrinkage rates. For high-load times, it corrects the curve using voltage drop calculations. This dynamic adaptation reduces unnecessary computational complexity while maintaining accuracy for each specific use case.
Solution Approach 2:
The invention performs partial determination actions based on needs: it calculates only the necessary parameters for the specific assessment context (low-load or high-load), avoiding full computation of all possible parameters. This reduces complexity while maintaining sufficient accuracy for the intended application.
Data Source
AI summary
An availability determination apparatus includes: a characteristic calculation portion that calculates a curve representing characteristics of a charging state and an open circuit voltage of a deteriorated secondary battery; a low-load determination portion that determines a use availability of the deteriorated secondary battery at a low load time based on a result of comparison between a first threshold value and a first capacity determined by an upper limit voltage and a lower limit voltage of the deteriorated secondary battery based on the curve representing the characteristics of the charging state and the open circuit voltage of the deteriorated secondary battery; and a high-load determination portion that calculates an upper limit voltage and a lower limit voltage of the deteriorated secondary battery after correction based on the curve representing the characteristics of the charging state and the open circuit voltage of the deteriorated secondary battery after correction, and determines a use availability of the deteriorated secondary battery at a high load time based on a result of comparison between a second threshold value and a second capacity determined by the upper limit voltage and the lower limit voltage of the deteriorated secondary battery after correction.