Lithium-Ion Battery Self-Discharge Screening via Multi-Stage Standing
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Solution Overview
Problem
Existing self-discharge screening methods for lithium-ion batteries, such as the K value method, suffer from limited accuracy due to reliance on standing duration, leading to poor screening results and safety concerns, especially with non-obvious type physical self-discharge abnormalities.
Innovation Solution
A multi-stage screening method involving high-temperature and room-temperature standing, combined with voltage drop analysis, to accurately identify and screen out batteries with chemical, obvious, general, and non-obvious type physical self-discharge abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the K value method is used for self-discharge screening, then the screening process is simple, but the accuracy of battery screening is poor due to limited standing duration
Solution Approach 1:
The patent divides the screening process into multiple stages: high-temperature standing stage, first room-temperature standing stage, second room-temperature standing stage, and physical self-discharge determination stage. Each stage performs specific screening functions, transforming a single long-duration screening into multiple short-duration stages that collectively achieve high accuracy without requiring excessively long total standing time.
Solution Approach 2:
The patent changes the standing temperature parameter between stages - using high temperature (e.g., 45℃) in the first stage to accelerate self-discharge reactions and reveal abnormalities quickly, then switching to room temperature in subsequent stages for stable measurement. This parameter change enables accurate screening within limited time by leveraging temperature-dependent reaction kinetics.
2Measurement precision
If multiple standing stages are performed to improve screening accuracy, then the measurement precision increases, but the time consumption increases
Solution Approach 1:
The patent implements periodic action by alternating between high-temperature standing periods and room-temperature standing periods. The high-temperature periods accelerate the detection of self-discharge abnormalities, while room-temperature periods allow for stable measurements and transitions. This periodic cycling achieves comprehensive screening accuracy without requiring continuous long-duration standing.
Solution Approach 2:
The high-temperature standing stage performs preliminary action by accelerating self-discharge reactions and revealing abnormal batteries early in the process. This preliminary acceleration allows subsequent room-temperature stages to focus on precise measurement of remaining candidates, reducing the total time required for accurate screening compared to uniform long-duration standing.
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
The method significantly improves the accuracy of self-discharge screening to ppb level, ensuring safety and quality by effectively identifying and removing batteries with all types of self-discharge failures, enhancing user trust and safety in lithium-ion batteries.
Implementation Method 1
performing high-temperature standing on the batteries to be tested that are at the preset state of charge
Implementation Method 2
determining physical self-discharge rates of the remaining batteries to be tested according to state parameters of the remaining batteries to be tested in the high-temperature standing, the first room-temperature standing and the second room-temperature standing
Data Source
AI summary
A self-discharge screening method and a self-discharge screening apparatus for lithium-ion batteries (500) are provided. The method includes: sequentially performing high-temperature standing, first room-temperature standing, and second room-temperature standing on batteries to be tested; screening the batteries to be tested according to state parameters of the first standing and the previous two periods of standing; determining physical self discharge rates of the remaining batteries to be tested according to the state parameters of the three periods of standing, and performing physical self-discharge screening on the remaining batteries to be tested. The physical self-discharge rates of the batteries to be tested are determined by using the state parameters, and batteries with non-obvious type physical self-discharge abnormalities are screened out.