Battery Separator With Magnetic Weak Line for Internal Short Testing
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Solution Overview
Problem
Existing methods for evaluating the safety of lithium secondary batteries during internal short circuits often require physical modifications to the battery structure, which do not accurately simulate real-world conditions.
Innovation Solution
A battery cell design featuring a separator with a perforated line and a magnetic body, where the magnetic body is positioned adjacent to the perforated line and arranged continuously or discontinuously, allowing an internal short circuit to be induced by rotating a magnet outside the battery cell without altering its structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical modifications are made to the battery structure to induce internal short circuit, then the internal short circuit can be effectively induced, but the separator is deformed and the test conditions differ from actual use environment
Solution Approach 1:
A weak line is pre-formed in the separator during manufacturing, creating a predetermined failure path. This allows the separator to fail in a controlled manner during safety testing without requiring aggressive physical modifications, thus maintaining test effectiveness while preserving separator integrity until the intended test moment.
Solution Approach 2:
The weak line acts as an intermediary element between the separator and the internal short circuit induction process. It provides a controlled failure mechanism that mediates between the need to induce short circuits and the need to maintain realistic test conditions, allowing safe and accurate testing without deforming the overall separator structure.
2Reliability
If aggressive methods are used to induce internal short circuit, then the short circuit can be reliably induced, but the test environment becomes different from actual use conditions
Solution Approach 1:
The weak line is prepared in advance during separator manufacturing, creating a built-in failure mechanism that enables reliable short circuit induction under controlled conditions. This preliminary preparation allows the same separator to perform accurately in both test and actual use environments, as the weak line only activates under specific test conditions.
Solution Approach 2:
The weak line introduces a localized area of reduced strength within the separator, while the rest of the separator maintains its normal structural properties. This localized modification allows reliable short circuit induction at specific locations without affecting the overall separator performance and realism in actual battery operation.
3Ease of manufacture
If the separator structure is physically altered to create failure points, then internal short circuit testing becomes possible, but the battery cell structure is permanently changed
Solution Approach 1:
The weak line is incorporated during separator manufacturing as a preliminary preparation, enabling future testing without requiring structural alterations at that stage. This approach maintains battery cell structural stability during storage and operation, while enabling easy testability when needed through controlled activation of the pre-formed weak line.
Solution Approach 2:
The weak line creates a controlled failure path that copies the essential characteristics of separator failure without requiring permanent structural changes to the battery cell. This allows repeated testing of multiple cells with identical designs, maintaining structural stability across the product line while enabling comprehensive safety evaluation.
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
This method effectively simulates an internal short circuit within the battery cell, enabling safe and accurate evaluation of its safety without physically changing the battery's structure, thus providing a more realistic assessment of its resistance to such conditions.
Implementation Method 1
a magnetic body which is formed in a region adjacent to the perforated line and does not overlap, and is arranged continuously or discontinuously at a position spaced apart from each other along the perforated line
Data Source
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AI summary
The present invention relates to a battery cell comprising a separator in which a perforated line and magnetic bodies adjacent to the perforated line are formed, and a method for evaluating battery cell safety by using same, wherein the battery cell can induce an internal short circuit without physical deformation of the cell structure, and can be effectively applied to evaluation of battery cell safety against an internal short circuit.