Secondary Battery Leakage Current Calculation for Low Voltage Defect Classification
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Solution Overview
Problem
Conventional methods for detecting low voltage defects in secondary batteries cannot quantitatively analyze the degree of failure, making it difficult to efficiently classify defective cells and improve the manufacturing process.
Innovation Solution
A method and system that calculate the leakage current using the time required and capacity change value during the aging process, allowing for a direct and quantitative indication of the low voltage expression level by measuring open circuit voltages and discharge voltage profiles, and distinguishing between self-discharge and internal short-circuit leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage drop difference is used to detect low voltage defects, then defect detection is possible, but quantitative analysis of the degree of failure cannot be performed
Solution Approach 1:
The patent transforms the detection parameter from voltage drop (qualitative) to leakage current (quantitative). By measuring the leakage current during the aging process and comparing it against reference values, the system can both detect defects and quantify their severity, thus resolving the contradiction between detection capability and quantitative information loss.
2Ease of operation
If conventional voltage drop method is used, then defect detection is simple, but efficient classification and process improvement cannot be achieved
Solution Approach 1:
The patent implements a feedback mechanism where leakage current measurements during aging provide quantitative data that feeds back into the manufacturing process. This enables efficient classification of defective cells by severity level and provides actionable feedback for process improvement, maintaining operational simplicity while dramatically improving productivity through data-driven decision making.
3Reliability
If aging process monitoring is performed, then low voltage expression level can be detected, but measurement and quantitative classification becomes complex
Solution Approach 1:
The patent uses leakage current as an intermediary parameter that bridges the gap between the aging process and defect quantification. Instead of directly measuring complex voltage expressions, the system measures the simpler leakage current during aging, which serves as a reliable proxy for low voltage expression level, thereby maintaining high reliability while reducing measurement system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient classification of defective cells based on quantitative leakage current values, improving the battery cell manufacturing process by providing accurate feedback on defect levels.
Implementation Method 1
calculating a self-discharge current by using time required for the defect inspection section and a capacity change value between the two capacities
Implementation Method 2
Soft-shorts generate precipitates, thereby causing low-voltage defects. Even when they are slightly short-circuited, ions move and current flows.
Data Source
AI summary
A method for calculating a leakage current of a precipitate by using a voltage drop amount result measured in an aging process according to a discharge voltage of a normal cell and a profile according to a discharge voltage of a normal cell and directly presenting a low voltage expression level based thereon.