Battery Internal Short-Circuit Evaluation Using Controlled Pressure
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Solution Overview
Problem
Conventional methods for evaluating the safety of lithium secondary batteries under internal short-circuit conditions are inaccurate, as they are influenced by the battery's constitution and structure, leading to improper evaluation of safety levels.
Innovation Solution
A method and device for causing a controlled internal short-circuit at a desired location within the battery, using pressure to remove a part of the insulating layer and detecting the short-circuit through changes in battery information such as voltage, temperature, sound, or light, allowing for comprehensive safety evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional evaluation methods (nail penetration test, crush test) are used to evaluate battery safety under internal short-circuit conditions, then the evaluation process is simple and easy to perform, but the evaluation accuracy is insufficient and cannot accurately reflect the actual safety level
Solution Approach 1:
The insulating layer is removed in advance from the target area before conducting the short-circuit test. This preliminary action ensures that when pressure is applied during the test, a controlled short-circuit occurs at the predetermined location, enabling accurate measurement of safety characteristics without the complexity of conventional methods.
Solution Approach 2:
A pressure-applying device is used as an intermediary to induce the internal short-circuit in a controlled manner. By applying pressure to the battery with the pre-prepared insulating layer removal, the device enables precise control over where and how the short-circuit occurs, improving measurement accuracy while maintaining operational simplicity.
2Quantity of substance
If the insulating layer is made thinner to increase battery capacity, then the energy density and capacity are improved, but the risk of internal short-circuit increases due to physical contact between electrodes
Solution Approach 1:
By removing the insulating layer in advance from specific areas, the invention creates controlled short-circuit points that allow for accurate safety evaluation. This enables manufacturers to assess and improve the reliability of thin insulating layer designs before mass production, ensuring that high-capacity batteries with thinner insulating layers maintain adequate safety standards.
Solution Approach 2:
The invention replaces random mechanical damage (such as nail penetration or crushing) with a controlled pressure-application system. This allows for precise control over the short-circuit location and conditions, enabling accurate evaluation of batteries with thin insulating layers and providing data to improve their reliability without sacrificing capacity.
3Reliability
If pressure is applied to cause internal short-circuit for safety evaluation, then the evaluation comprehensiveness is improved, but the risk of causing actual battery damage or thermal runaway increases
Solution Approach 1:
The insulating layer is removed in advance from the target area, which confines the short-circuit to a specific, controlled location. This preliminary preparation ensures that when pressure is applied during testing, the short-circuit occurs only where intended, preventing uncontrolled thermal runaway and reducing the risk of actual battery damage while maintaining comprehensive safety evaluation.
Solution Approach 2:
The invention inherently provides a form of cushioning by controlling the short-circuit location through pre-removal of the insulating layer. This control acts as a safety mechanism that prevents the short-circuit from spreading uncontrollably, thereby reducing the harmful effects during testing while still enabling comprehensive safety assessment.
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 approach enables accurate evaluation of battery safety under internal short-circuit conditions, independent of the battery's local constitution, providing reliable safety rankings and optimal usage designs.
Implementation Method 1
applying a pressure to a battery to cause an internal short-circuit
Implementation Method 2
the short-circuit further expands due to Joule's heat generated by the short-circuit current
Implementation Method 3
detecting the occurence of the internal short circuit by detecting battery information obtained from the battery
Implementation Method 4
detecting changes in battery temperature, battery voltage
Implementation Method 5
detecting battery information obtained from the battery or by visual inspection
Data Source
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AI summary
Methods for evaluating battery safety under internal short-circuit conditions are improved to eliminate variations in evaluation results and accurately evaluate battery safety under internal short-circuit conditions. An internal short-circuit is caused in a battery by using an internal short-circuit causing method in which battery information obtained upon the occurrence of an internal short-circuit hardly changes with the structure of the battery. At this time, the battery information is detected to accurately evaluate the safety of the battery upon the internal short-circuit and identify the safety level.