Wound Electrode Assembly Slits for Uniform Electrolyte Impregnation
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Solution Overview
Problem
Conventional electrode assemblies face limitations in improving electrolyte impregnation properties, especially in larger battery sizes, leading to reduced performance and energy density, and require enhanced electrolyte distribution and contact area with current collectors to minimize internal resistance and enhance coupling strength.
Innovation Solution
The electrode assembly incorporates a non-coated portion with strategically arranged impregnation slits and fragments to create a wide contact area with the current collector, ensuring uniform electrolyte impregnation and improved structural integrity, including staggered slit positions and bent fragments to enhance electrolyte flow and reduce internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the battery size is increased to improve energy density, then the energy density increases, but the electrolyte impregnation property deteriorates in the central part of the electrode
Solution Approach 1:
The electrode assembly is divided into multiple segments with non-coated portions created at regular intervals along the winding axis. These segmented non-coated portions serve as electrolyte impregnation paths, allowing electrolyte to penetrate uniformly throughout the large battery structure, thereby resolving the contradiction between increased battery size for higher energy density and maintained electrolyte impregnation properties
2Quantity of substance
If the battery size is increased to improve energy density, then the energy density increases, but the internal resistance increases due to reduced contact area with current collector
Solution Approach 1:
The electrode assembly is segmented into multiple non-coated portions that serve as contact points with the current collector. This segmentation increases the total contact area between the electrode and current collector, thereby reducing internal resistance while maintaining the larger battery size needed for high energy density
3Quantity of substance
If the battery size is increased to improve energy density, then the energy density increases, but the coupling strength between electrode assembly and current collector decreases
Solution Approach 1:
The electrode assembly is divided into multiple non-coated portions that are bent to wrap around and contact the current collector at multiple locations. This segmented approach distributes the coupling force across multiple contact points, thereby maintaining strong coupling strength even in larger batteries with higher energy density
Solution Approach 2:
The non-coated portions are bent into curved shapes that conform to the cylindrical current collector surface. This curvature enables better surface contact and mechanical interlocking, enhancing the coupling strength between the electrode assembly and current collector in large-form-factor batteries
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 improves electrolyte impregnation properties, reduces internal resistance, and strengthens the coupling between the electrode assembly and current collector, leading to increased energy density and safety against thermal runaway.
Implementation Method 1
forming an impregnation slit through which electrolyte can pass on a non-coated portion of the battery so that the electrolyte is uniformly impregnated in an entire electrode assembly type electrode assembly accommodated inside the battery
Data Source
AI summary
An electrode assembly includes a first electrode, a second electrode, and a separator interposed therebetween. The first electrode, the second electrode and separator are wound in a winding direction about a winding axis to define a core and an outer circumference of the electrode assembly. The first electrode includes an active material portion coated with an active material layer and a first non-coated portion not coated with the active material layer along the winding direction. The first non-coated portion includes a plurality of impregnation slits extending along a circumferential direction of the electrode assembly. Longitudinal extension lines of impregnation slits adjacent to each other along the circumferential direction do not overlap each other.