Battery Health Estimation from Constant-Voltage Current Decay
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Solution Overview
Problem
Existing battery health monitoring methods are ineffective during constant voltage operation and fail to detect certain faults, particularly electrolyte faults, due to low observability during constant current phases.
Innovation Solution
Battery state health estimation using current characteristics at a constant voltage, employing derived equations for the expected current profile and monitoring health indicators such as the slope of the natural log of current and coefficient of determination, to detect faults like electrolyte issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If battery health monitoring is performed during constant current operation, then monitoring can be performed, but certain faults (particularly electrolyte faults) cannot be detected due to low observability
Solution Approach 1:
The patent changes the operational parameter from constant current to constant voltage phase for monitoring. During constant voltage charging, the current naturally decays over time following a predictable pattern. By analyzing the current characteristics (slope of current decay, coefficient of determination) during this phase, the system can detect faults that are invisible during constant current operation, thereby improving fault detection capability while overcoming the observability limitation.
2Productivity
If existing monitoring methods are used, then simple monitoring is possible, but battery faults remain undetected leading to reduced maintenance efficiency
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors current characteristics during constant voltage charging and compares them against expected patterns. By calculating the slope of current decay and the coefficient of determination, the system provides feedback about battery health status. This enables timely detection of faults and triggers appropriate maintenance actions, thereby improving both maintenance efficiency and fault detection accuracy simultaneously.
Data Source
AI summary
Examples described herein provide a method that includes detecting a start of a constant voltage operation phase of a battery of a vehicle. The method further includes collecting current information and voltage information about the battery. The method further includes monitoring a health indicator for the battery based at least in part on the current information. The method further includes determining whether the battery is in a healthy state or a fault state by determining whether the health indicator is within an acceptable range. The method further includes, responsive to determining that the battery is in the fault state, implementing a corrective action for the battery.