Battery Separator Breakdown Testing Under Standardized Foreign Matter
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Solution Overview
Problem
Existing secondary battery safety evaluations do not adequately address the risk of internal short circuits caused by foreign matter, which can lead to insulation breakdown and potential ignition due to the unpredictable shape and size of foreign particles.
Innovation Solution
A device and method for evaluating separator safety by using standardized foreign matter with controlled shapes and sizes, applying pressure to simulate real-world conditions, and measuring breakdown voltage to determine the separator's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If foreign matter with unpredictable shape and size is used in safety evaluation, then the evaluation covers real-world variability, but the measurement results become inconsistent and unreliable
Solution Approach 1:
The patent changes the parameters of foreign matter from unpredictable natural variations to controlled standardized dimensions. Specifically, it defines foreign matter with predetermined sizes (e.g., 100 μm, 200 μm, 300 μm diameter spheres) and standardized shapes, transforming the evaluation from dealing with random variables to testing with controlled parameters. This allows consistent reproduction of test conditions while maintaining evaluation relevance.
Solution Approach 2:
The patent creates simplified copies of real foreign matter by using standardized spherical objects with controlled dimensions. Instead of using actual irregular foreign particles found in battery manufacturing, it employs idealized spherical copies that represent the critical dimension (size) without the complexity of real particle shapes. This copying approach enables consistent measurement while capturing the essential safety concern.
2Reliability
If pressure is applied to simulate real-world conditions, then the evaluation becomes more realistic, but the test sample structure may deform
Solution Approach 1:
The patent applies partial pressure - enough to simulate real-world compression conditions and induce meaningful stress on the separator, but controlled to avoid complete structural collapse. The pressure is applied incrementally or held at specific levels that are sufficient to reveal safety issues without destroying the entire test sample structure, allowing measurement to proceed.
Solution Approach 2:
The patent performs preliminary setup by carefully assembling the test sample with standardized foreign matter positioned between electrodes and separator before applying pressure. This preliminary configuration ensures that when pressure is applied, the stress is distributed in a controlled manner that simulates real conditions while maintaining structural integrity for measurement.
3Measurement precision
If breakdown voltage measurement is used to assess separator safety, then the evaluation is quantifiable, but the test requires complex measurement equipment and procedures
Solution Approach 1:
The patent makes the breakdown voltage measurement system multi-functional by using it to assess both electrical insulation properties and mechanical strength under pressure. The same measurement apparatus evaluates separator performance across different foreign matter sizes and pressure conditions, reducing the need for separate specialized equipment for each type of safety evaluation.
Solution Approach 2:
The patent introduces standardized foreign matter as an intermediary element that mediates between the applied pressure and the separator's electrical insulation. This intermediary allows the measurement system to indirectly assess separator safety by measuring breakdown voltage in the presence of controlled foreign objects, simplifying the overall measurement approach compared to direct structural analysis.
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
Enhances the reliability of safety evaluations by standardizing foreign matter shape and size, providing consistent and reliable results for assessing separator integrity under various pressure conditions.
Implementation Method 1
a pressing unit configured to apply a pressure to a test sample
Implementation Method 2
an insulation breakdown measurement unit configured to apply a voltage to the first electrode and the second electrode to measure a breakdown voltage
Implementation Method 3
If a short circuit current flows through the short circuit path, Joule heat may be generated
Data Source
AI summary
A device for evaluating the safety of a separator, including: a pressing unit to apply a pressure to a test sample including a first electrode, a standardized foreign matter, a separator, and a second electrode; an insulation breakdown measurement unit to apply a voltage to the first electrode and the second electrode to measure a breakdown voltage; and a controller to control the pressing unit and the insulation breakdown measurement unit, and determine the safety of the separator based on the measured breakdown voltage. In the test sample, the first electrode, the standardized foreign matter, the separator, and the second electrode are sequentially stacked, and the standardized foreign matter is located between the first electrode and the separator.