Lead-Acid Battery Short-Circuit Estimation Using SOC Error Analysis
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Solution Overview
Problem
Conventional techniques fail to predict the generation of internal short-circuits in lead-acid batteries, which can lead to sudden power failure due to factors like separator degradation or foreign material contact, as they cannot estimate this condition beforehand.
Innovation Solution
An estimation device and method that acquires voltage, current, and temperature data to derive state of charge (SOC) and overcharge amounts, calculating actual and estimation errors to specify an abnormality degree, thereby estimating the generation of internal short-circuits based on these parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional temperature-based degradation determination is used, then degradation can be detected, but internal short-circuit generation cannot be predicted
Solution Approach 1:
The invention performs preliminary actions by continuously monitoring charge-discharge ratios and voltage values before internal short-circuits occur. It calculates deviation amounts from normal ranges and accumulates abnormality scores in advance, enabling prediction and early warning before the actual short-circuit event happens, thus resolving the inability to predict internal short-circuits with conventional methods.
2Reliability
If simple temperature monitoring is implemented, then the system remains simple, but it cannot detect internal short-circuit conditions
Solution Approach 1:
The invention makes the existing battery management system multi-functional by enabling it to perform both conventional temperature-based degradation monitoring and new internal short-circuit prediction functions. The same monitoring infrastructure is used to calculate charge-discharge ratios and voltage deviations, allowing one system to serve multiple purposes without proportionally increasing complexity.
Solution Approach 2:
The invention introduces new detection parameters (charge-discharge ratio, voltage deviation from normal range, abnormality score) that transform the monitoring approach. By changing from simple temperature monitoring to multi-parameter analysis, the system gains the ability to detect internal short-circuit conditions while maintaining manageable complexity through systematic parameter management.
3Reliability
If continuous monitoring of charge-discharge ratios and voltage is performed, then internal short-circuit prediction is enabled, but data processing complexity increases
Solution Approach 1:
The system performs self-service by automatically calculating charge-discharge ratios, comparing voltage values against stored normal ranges, computing deviation amounts, and accumulating abnormality scores without external intervention. The battery management system serves itself by processing its own operational data to generate predictions, reducing the need for external complex processing infrastructure.
Solution Approach 2:
The invention implements feedback mechanisms where voltage measurements and charge-discharge ratios are continuously compared against normal ranges, and deviation amounts feed into abnormality score calculations. This feedback loop enables automatic adjustment and continuous refinement of predictions based on real-time data, managing processing complexity through structured feedback rather than uncontrolled data accumulation.
Data Source
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AI summary
An estimation device includes: an acquisition unit that acquires a voltage, a current, and a temperature of a lead-acid battery; a first deriving unit that derives a first SOC and a second SOC that are SOCs of a start point and an end point of an estimation period; a second deriving unit that derives a total amount of an overcharge amount in the estimation period; a third deriving unit that derives an actual measurement error based on a difference between the first SOC and the second SOC and the total amount of the overcharge amount; a first specification unit that specifies an estimation error based on the first SOC, the second SOC, and the temperature, and a relationship between the first SOC, the second SOC, and the temperature of the lead-acid battery, and the estimation error; a second specification unit that specifies an abnormality degree of the actual measurement error based on the derived actual measurement error and the specified estimation error; and an estimation unit that estimates generation of an internal short-circuit of the lead-acid battery based on the abnormality degree.