Serpentine Separator Electrode Stack for Uniform Adhesion and Porosity
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Solution Overview
Problem
Existing electrode assemblies in secondary batteries face issues with deviations in adhesive force and air permeability across layers, which can lead to side-effects like lithium precipitation and non-charging.
Innovation Solution
The electrode assembly is designed with a stack of electrodes separated by a serpentine-folded elongated separator, ensuring consistent adhesive force and air permeability across layers, and incorporating a manufacturing process involving primary and secondary heat press operations to achieve structural stability and high safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If electrode thickness is increased to maintain adequate adhesive force, then adhesive force is improved, but air permeability deteriorates and deviations across layers increase
Solution Approach 1:
The patent controls the thickness parameter of electrodes within a specific range (maximum thickness less than 8.3 mm, with bottom electrode thickness being 80-120% of top electrode thickness) to optimize both adhesive force and air permeability. This parameter control resolves the contradiction by finding the optimal thickness range that satisfies both requirements simultaneously.
2Stability of the object's composition
If electrode thickness is increased to maintain structural stability, then structural stability is improved, but deviations in adhesive force and air permeability across layers increase
Solution Approach 1:
The patent specifies that the bottom electrode thickness should be 80-120% of the top electrode thickness, and maximum electrode thickness should be less than 8.3 mm. This controlled parameter variation maintains structural stability while minimizing deviations across layers.
Solution Approach 2:
The patent allows asymmetric thickness between top and bottom electrodes (bottom electrode can be 80-120% of top electrode thickness) rather than requiring exact symmetry. This controlled asymmetry enables optimization of both structural stability and uniformity across layers.
3Reliability
If separator air permeability is increased to improve safety, then safety is improved, but adhesive force between separator and electrodes deteriorates
Solution Approach 1:
The patent optimizes the air permeability parameter of the separator to a specific range that simultaneously ensures adequate safety and maintains sufficient adhesive force with electrodes. This parameter optimization resolves the contradiction between safety and adhesion.
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 configuration prevents lithium precipitation and non-charging, while maintaining adequate adhesive force and air permeability, resulting in a structurally stable and safe electrode assembly with improved performance.
Implementation Method 1
the elongated separator sheet may be folded between each separator portion such that the elongated separator sheet follows a serpentine path traversing back and forth along an orthogonal dimension orthogonal to the stacking axis
Implementation Method 2
incorporating a manufacturing process involving primary and secondary heat press operations to achieve structural stability
Data Source
AI summary
An electrode assembly includes a plurality of electrodes arranged in a stack along a stacking axis with a respective separator portion of an elongated separator sheet positioned between and winding around each of the electrodes in the stack along a serpentine path. The plurality of electrodes include a top electrode positioned at a top of the stack along the stacking axis, and the plurality of electrodes include a bottom electrode positioned at a bottom of the stack. The separator portions in the stack include a top separator portion abutting the top electrode and a bottom separator portion abutting the bottom electrode. The bottom electrode may have a thickness along the stacking axis that is from 80% to 120% of a thickness of the top electrode along the stacking axis. Moreover, a maximum thickness of each of the electrodes in the stack may be less than 8.3 mm.