Battery Deterioration Detection via Resistance-Current Correlation
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Solution Overview
Problem
Existing battery technologies face complexity in estimating the degree of increase in battery resistance due to wear and salt concentration distribution, as these types of deterioration have different effects on internal resistance, making it difficult to accurately determine and address the underlying cause of battery deterioration.
Innovation Solution
A battery system and method that utilize correlations between resistance change rate and current value to differentiate between deterioration due to wear and salt concentration distribution, allowing for specific processing to address each type of deterioration, with the controller determining the deterioration state based on the susceptibility of battery voltage to positive and negative electrode potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a battery model is used to estimate battery resistance increase, then the estimation can be performed, but the processing becomes complicated
Solution Approach 1:
The patent extracts the essential relationship between resistance change rate and current value from the complex battery model, separating the key diagnostic information from the complicated modeling process. By focusing only on the resistance-current relationship in less charged states, the system obtains accurate deterioration detection without requiring full battery model complexity.
Solution Approach 2:
The patent creates a simplified correlation model that copies only the necessary resistance change characteristics from the full battery model. Instead of using the complete complex model, it replicates the essential resistance-current relationship pattern, achieving accurate deterioration detection with reduced processing complexity.
2Measurement precision
If general battery deterioration detection is performed, then wear deterioration can be detected, but salt concentration distribution deterioration cannot be distinguished
Solution Approach 1:
The patent segments deterioration detection into two distinct types by analyzing resistance change patterns at different current values. By dividing the detection approach into wear-related resistance changes and salt concentration-related resistance changes, the system can identify and distinguish between different deterioration mechanisms that would otherwise be indistinguishable.
Solution Approach 2:
The patent applies different analysis criteria to different aspects of resistance change. By examining how resistance changes locally with respect to current value variations, the system can identify specific signatures of salt concentration distribution issues versus wear issues, preserving deterioration type information through localized analysis of resistance characteristics.
Data Source
AI summary
A battery system includes a secondary battery and a controller. A battery voltage of the secondary battery is more susceptible to a positive electrode potential than to a negative electrode potential. The controller acquires a relationship between a resistance change rate and a current value in the secondary battery in a less charged state and determines the deterioration state of the secondary battery based on the acquired relationship. The controller determines the deterioration state of the secondary battery by using a first correlation and a second correlation. In the first correlation, the resistance change rate is reduced as the current value is increased when only deterioration due to wear of the secondary battery (wear deterioration) occurs. In the second correlation, the resistance change rate is increased as the current value is increased when only deterioration due to a salt concentration distribution within the secondary battery (high rate deterioration) occurs.