Battery Degradation Estimation From Charging Curve Slopes
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Solution Overview
Problem
Existing methods for secondary battery degradation determination, such as those described in JP 2022-020404, require significant time and resources as they need to fully charge and discharge batteries to acquire charging and discharging characteristics, making them inefficient for recycling companies to assess battery reuse.
Innovation Solution
A secondary battery degradation determination apparatus and method using a processor to calculate an estimated electric capacity based on charging and discharging curves, employing multiple regression models, multilayer neural networks, or gradient boosting of decision trees, allowing for quick and efficient degradation determination by analyzing voltage slopes, temperatures, and derivatives of voltage values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full charge and discharge cycles are performed to acquire charging and discharging characteristics, then degradation determination accuracy is improved, but determination time increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-acquiring charging and discharging characteristics data during battery manufacturing or initial use, and storing this data in advance. When degradation determination is needed, the system directly compares current battery performance against this pre-stored baseline data, eliminating the need to perform time-consuming full charge-discharge cycles at the time of assessment. This allows rapid degradation evaluation while maintaining accuracy through comparison with historically accurate battery characteristics.
2Measurement precision
If multiple charge-discharge cycles are performed to acquire charging characteristics, then measurement accuracy is improved, but productivity decreases
Solution Approach 1:
The patent employs copying by creating a digital replica or model of the battery's original charging and discharging characteristics. Instead of physically performing multiple charge-discharge cycles to measure battery performance, the system uses stored characteristic curves and models to represent battery behavior. This digital copy allows rapid assessment of degradation by comparing current performance against the stored characteristic model, dramatically increasing throughput while maintaining measurement accuracy.
3Reliability
If comprehensive charging and discharging characteristics are measured, then degradation determination reliability is improved, but device complexity and resource requirements increase
Solution Approach 1:
The patent applies the extraction principle by isolating and utilizing only the most critical charging and discharging characteristic parameters needed for degradation assessment. Rather than measuring and analyzing all possible battery characteristics, the system extracts key parameters such as charge acceptance rate, discharge voltage curves, and capacity retention metrics. This selective extraction maintains degradation determination reliability by focusing on the most indicative parameters while reducing system complexity and resource requirements.
Data Source
AI summary
A secondary battery degradation determination apparatus configured to perform degradation determination for a secondary battery as a determination target includes a processor. The processor is configured to calculate an estimated electric capacity of the secondary battery, based on at least a slope between any two points on a charging curve indicating a charging characteristic of the secondary battery; and perform the degradation determination for the secondary battery, based on the estimated electric capacity that is calculated.