Radial Electrode Assembly for Lower Resistance Battery Cells
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Solution Overview
Problem
Existing electrode assemblies in secondary batteries face issues with increased electron transfer resistance and structural instability, particularly in high-current operations, due to the distance electrons must travel through the positive and negative electrode current collectors, and variations in electrolyte solution concentration affecting ion conductivity.
Innovation Solution
The electrode assembly is designed with a radial structure where the thickness of the unit cells decreases towards the center, featuring electrode tabs on the edges of current collectors, and through-holes in the collectors to reduce electron travel distance and maintain consistent electrolyte concentration, enhancing ion transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the electrode assembly uses a conventional jelly-roll structure with rectangular sheets, then the manufacturing is easy and energy density per unit weight is high, but the electron transfer resistance increases due to long electron travel distance through current collectors
Solution Approach 1:
The patent transforms the conventional two-dimensional rectangular electrode sheets into a three-dimensional radial cylindrical structure. The electrode sheets are wound in a radial direction around a central axis, creating a cylindrical electrode assembly. This dimensional transformation allows electron tabs to be positioned at multiple locations (including the central axis and outer circumference), significantly reducing the maximum electron travel distance through the current collector while maintaining the jelly-roll manufacturing advantages
Solution Approach 2:
The patent segments the electrode assembly into multiple electrode sheets stacked in a radial configuration. Each electrode sheet includes current collectors with active material layers, and the radial stacking creates multiple electron conduction paths from the outer circumference to the central axis. This segmentation provides multiple parallel electron transport routes, reducing overall electron transfer resistance while maintaining structural integrity
2Reliability
If the electrode assembly uses a cylindrical radial structure, then the electron transfer distance is reduced and ion conductivity is improved, but the weight increases
Solution Approach 1:
The patent applies local quality by positioning electrode tabs and current collector thickness strategically within the radial structure. The current collectors are designed with optimized thickness distribution, and tabs are placed at specific radial locations (central axis and outer circumference) to maximize ion conductivity in the electrolyte-saturated regions while minimizing unnecessary material usage. This localized optimization improves ion transport without proportionally increasing overall weight
3Productivity
If the current collector has large surface area for electrode tabs, then the electron collection efficiency is improved, but the amount of active material decreases
Solution Approach 1:
The radial cylindrical configuration transforms the electron collection geometry from a planar surface to a three-dimensional radial structure. Electron tabs can be positioned at the central axis and outer circumference, creating multiple collection points that efficiently gather electrons from throughout the electrode assembly volume. This dimensional arrangement improves electron collection efficiency without requiring excessive current collector surface area, preserving more space for active material
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 reduces electron transfer resistance and maintains stable ion conductivity, improving the performance and structural stability of the secondary battery while minimizing weight increase.
Implementation Method 1
lithium ions in an electrolyte solution express high ion conductivity within a specific concentration range
Implementation Method 2
a distance for electrons to move from the positive electrode tab or the negative electrode tab through the positive electrode current collector or the negative electrode current collector increases
Data Source
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AI summary
An electrode assembly according to an embodiment of the present invention includes a plurality of unit cells for forming a radial structure with reference to a center, wherein a thickness of the unit cell is reduced while going to the center from an external side of the radial structure with respect to a horizontal cross-section, and an electrode tab is formed on at least one of an upper edge, a lower edge, an external edge, and a center edge of a current collector included in the unit cell.