Battery Module Spring End Plates for Uniform Cell Swelling Pressure
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Solution Overview
Problem
Lithium secondary battery cells experience sudden death and performance deterioration due to non-uniform pressure distribution during swelling, leading to interrupted electrical connections.
Innovation Solution
A battery module with a casing and elastic members, such as springs, is designed to apply uniform pressure to battery cells by coupling springs to the edge portions of end plates, allowing adjustable pressure control through spring constant adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the battery cell is pressed at the edge portion with higher rigidity end plate, then the structural support is improved, but the pressure distribution becomes non-uniform causing sudden death phenomenon
Solution Approach 1:
The end plate is designed with locally distributed elastic members (springs) at specific positions to provide localized pressure compensation. This creates non-uniform local properties on the otherwise rigid end plate, allowing different regions to exert different pressures on the battery cell to achieve uniform overall pressure distribution.
Solution Approach 2:
Elastic members (springs) are introduced as intermediary elements between the rigid end plate and the battery cell. These springs act as mediators that transform the rigid contact into a compliant interface, enabling uniform pressure distribution while maintaining structural support.
2Strength
If the end plate has high rigidity for structural support, then the mechanical strength is improved, but the pressure applied to battery cells becomes non-uniform during swelling
Solution Approach 1:
The end plate incorporates elastic members at strategically positioned locations to create local compliance zones. This allows the majority of the end plate to maintain high rigidity for structural support while specific local regions provide pressure equalization through the elastic members.
Solution Approach 2:
The system changes the mechanical parameter (rigidity) locally by introducing elastic members with different stiffness characteristics. This creates a hybrid structure where rigid and compliant regions coexist, enabling both structural strength and uniform pressure distribution.
3Reliability
If elastic members are added to achieve uniform pressure distribution, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The elastic member system is segmented into multiple discrete springs positioned at specific locations rather than using a continuous complex mechanism. This segmentation simplifies the overall structure while achieving the desired pressure distribution through distributed point contacts.
Solution Approach 2:
The elastic members (springs) are self-adjusting components that automatically regulate pressure distribution based on battery cell swelling without requiring external control systems. This self-service mechanism simplifies the control architecture while maintaining reliability.
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
Prevents sudden death phenomena by ensuring uniform pressure distribution across battery cells during swelling, maintaining performance and electrical connectivity.
Implementation Method 1
an elastic member coupled to an inner side of the casing while avoiding an interference with the battery cells so that a uniform pressure is formed at the battery cells when swelling occurs at the battery cells
Data Source
Figure 1(a)~1(b)
Figure 2~3
Figure 4
AI summary
Disclosed is a battery module. The battery module includes: a battery cell stack having a plurality of battery cells stacked on one another; a casing configured to surround the battery cell stack; and an elastic member coupled to an inner side of the casing while avoiding an interference with the battery cells so that a uniform pressure is formed at the battery cells when swelling occurs at the battery cells.