Battery Module Fastening Band Layout for Uniform Cell Pressure
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Solution Overview
Problem
Existing battery modules experience uneven pressure distribution during expansion due to lack of precise pressure control, leading to degraded electrical cycle performance, short-circuiting, and failure from displacement of fastening assemblies.
Innovation Solution
A battery module design featuring fastening bands that enclose the cell assembly with specific distance projections relative to the cell body ends, a housing with grooves to stabilize the bands, and an end plate to enhance pressure resistance, ensuring balanced pressure application and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional pressurization is applied to limit cell assembly expansion, then cycle performance is improved, but pressure distribution becomes uneven causing harmful effects
Solution Approach 1:
The pressurization system is segmented into multiple fastening bands positioned at specific locations (within L/4 from each end of the cell body) rather than a single uniform pressurization method. This segmentation allows different regions to be pressurized independently, achieving balanced overall pressure distribution while preventing uneven stress concentration that would harm cycle performance
Solution Approach 2:
The patent applies local quality by positioning fastening bands at specific locations (within L/4 from each end) rather than uniform distribution. This localized pressurization approach ensures that critical end regions receive appropriate pressure to prevent expansion while avoiding excessive pressure on the middle region, thereby achieving uniform pressure distribution across the entire cell assembly
2Stability of the object's composition
If fastening bands are positioned too close to cell ends, then expansion is limited, but short-circuiting or displacement failure occurs
Solution Approach 1:
The fastening bands are pre-positioned within L/4 from each end of the cell body before charge-discharge cycling begins. This preliminary positioning ensures that the cell assembly is properly constrained from the start, preventing excessive expansion that could lead to short-circuiting or fastening assembly displacement while maintaining reliable operation throughout the battery's lifecycle
3Stability of the object's composition
If middle region is pressurized excessively, then expansion is controlled, but structural damage occurs
Solution Approach 1:
The patent implements local quality by strategically positioning fastening bands within L/4 from each end of the cell body, creating a non-uniform pressurization distribution. This ensures that the middle region is not subjected to excessive pressure while still achieving effective expansion control, thereby preserving the structural integrity and strength of the cell assembly
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
The design improves cycle performance by maintaining equilibrium pressure distribution, reducing the risk of short-circuiting, and preventing structural damage, thereby enhancing the battery module's operational efficiency.
Implementation Method 1
The fastening band is provided to apply a pressure to the cell assembly, so that expansion of the cell assembly during a charge and discharge cycle is limited
Data Source
AI summary
A battery module includes a cell assembly, where a cell in the cell assembly includes a cell body and a tab; and the battery module further includes: a first fastening band, configured to enclose the cell assembly in a thickness direction of the cell; and a second fastening band, configured to enclose the cell assembly in the thickness direction of the cell, where in a length direction of the cell, a distance between a projection location of the first fastening band and a first end of the cell body is less than or equal to L/4, a distance between a projection location of the second fastening band and a second end of the cell body is less than or equal to L/4, and L is length of the cell body.