Secondary Battery Electrode Assembly Thermal Shrinkage Prevention
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Solution Overview
Problem
Secondary batteries are prone to short circuits when exposed to high temperature environments due to thermal shrinkage of the separator, leading to potential explosions.
Innovation Solution
The secondary battery design includes an electrode assembly with an outermost electrode and inner electrode, where the separator extends beyond the inner electrode by 3 cm or more in the lengthwise direction, preventing direct contact between the electrodes during thermal shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outermost electrode and separator are extended beyond the inner electrode by 3 cm or more, then short circuits are prevented during thermal shrinkage, but the electrode assembly complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the length parameter of the outermost electrode and separator, extending them by 3 cm or more beyond the inner electrode. This quantitative change in dimension provides a simple yet effective solution to prevent short circuits during thermal shrinkage without requiring complex structural modifications or additional components.
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 design effectively prevents short circuits and explosions by allowing the separator to shrink without causing contact between the electrodes, as demonstrated by extended operating times and safe discharge of gases during combustion tests at high temperatures.
Implementation Method 1
the separator insulating the positive electrode and the negative electrode thermally may shrink
Data Source
AI summary
A secondary battery including an electrode assembly comprises: an outermost electrode an electrode assembly comprising an outermost electrode, an inner electrode, and a separator disposed between the outermost and inner electrodes, wherein the outermost electrode, the inner electrode and the separator are wound together; a case that accommodates the electrode assembly; and a cap assembly coupled to the case, wherein the outermost electrode and the separator disposed under the outermost electrode extend beyond the inner electrode disposed under the separator in a lengthwise direction of the winding by 3 cm or greater.