Battery Deterioration Estimation via Salt Concentration Correction
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Solution Overview
Problem
Existing methods for estimating the deterioration state of secondary batteries, particularly those affected by salt concentration imbalances, lack accuracy in distinguishing and quantifying the high-rate deterioration component, which is exacerbated by continuous charge and discharge prohibition.
Innovation Solution
An estimation apparatus and method that utilize a current sensor, a battery model, and a deterioration estimating section to correct the estimated current by using the ratio between resistance change rates and capacitance retention rates, allowing for the accurate estimation of the high-rate deterioration component associated with salt concentration imbalances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If charge and discharge of the secondary battery are continuously prohibited to eliminate salt concentration imbalance, then the high-rate deterioration component is eliminated, but the time required for deterioration estimation increases
Solution Approach 1:
The system performs preliminary action by prohibiting charge and discharge before deterioration estimation to eliminate salt concentration imbalance. This preliminary rest period allows the battery to reach a stable state where salt concentration is balanced, ensuring accurate estimation of the high-rate deterioration component before normal operation resumes.
Solution Approach 2:
The system dynamically adjusts the estimation process by detecting whether salt concentration imbalance exists and selectively applying the prohibition of charge and discharge only when necessary. The deterioration estimation is performed adaptively based on real-time battery conditions, optimizing the balance between accuracy and time efficiency.
2Reliability
If the high-rate deterioration component is detected based on the difference between measured current and estimated current, then the deterioration can be identified, but the precision of distinguishing the high-rate deterioration component from wear deterioration is insufficient
Solution Approach 1:
The deterioration is segmented into two distinct components: the first deterioration component (wear deterioration) and the second deterioration component (high-rate deterioration). By separating these components and estimating them independently through different methods, the system achieves precise distinction between the two types of deterioration that cannot be achieved by simple current difference measurement.
Solution Approach 2:
The battery model serves as an intermediary tool to estimate the first deterioration component based on charge and discharge cycles, while the current sensor provides the second deterioration component based on actual measurements. This intermediary approach allows accurate separation and quantification of different deterioration mechanisms.
Data Source
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AI summary
[PROBLEM] To estimate a second deterioration component included in a deterioration state of a secondary battery. [SOLVING MEANS] An estimation apparatus of estimating a deterioration state of a secondary battery has a current sensor measuring an electric current of the secondary battery, a current estimating section estimating the electric current of the secondary battery by using a battery model, and a deterioration estimating section estimating a second deterioration component produced in association with a salt concentration imbalance in the secondary battery. The deterioration estimating section estimates the second deterioration component by using the measured current obtained from the current sensor, the estimated current obtained from the current estimating section, and a first deterioration component produced in association with wear of the secondary battery. The deterioration estimating section corrects the estimated current by using a ratio between a resistance change rate of the secondary battery when the second deterioration component is eliminated and a resistance change rate during charge and discharge of the secondary battery.