Electrode Assembly Welding Layout for Uniform Electrolyte Permeation
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Solution Overview
Problem
In power storage cells, the permeation of electrolyte solution within the electrode assembly becomes uneven due to the repeated expansion and contraction during charging and discharging, leading to potential electrolyte depletion in the central portion.
Innovation Solution
The electrode assembly is designed with specific welding portions at the ends and bottom to block the entry and exit of electrolyte solution, ensuring uniform permeation by forming micropores in the separator that are closed during expansion and contraction, maintaining electrolyte distribution in the corner portions of the bottom portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode assembly is formed with a laterally long shape allowing electrolyte solution to enter and exit via the periphery, then the initial electrolyte permeation is maintained, but with passage of time the electrolyte solution is exhausted in the central portion leading to uneven permeation
Solution Approach 1:
The electrode assembly is divided into multiple independent pouches arranged in parallel, with each pouch containing its own electrode assembly and electrolyte solution. This segmentation prevents the electrolyte in one region from being depleted by blocking its path to the periphery, thereby maintaining uniform permeation across the entire assembly over extended service time.
Solution Approach 2:
Absorbent members are introduced as intermediary elements between the electrode assemblies and the electrolyte solution reservoir. These members actively transport electrolyte solution from the reservoir to the electrode assemblies through capillary action, ensuring continuous and uniform supply to all regions including the central portion, thereby preventing electrolyte exhaustion over time.
2Reliability
If welding portions are formed to block electrolyte solution entry and exit, then electrolyte distribution uniformity is maintained, but the structure becomes more complex
Solution Approach 1:
Multiple electrode assemblies are merged into a single packaged unit with shared electrolyte solution reservoir and external terminals. This merging reduces overall structural complexity while maintaining uniform electrolyte distribution through the segmented internal architecture and absorbent member network.
Solution Approach 2:
The absorbent members serve multiple functions: they act as electrolyte transport channels, provide structural spacing between components, and function as separators. This multi-functionality reduces the need for additional dedicated components, thereby simplifying the overall structure while ensuring uniform electrolyte distribution.
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 uneven electrolyte solution permeation inside the electrode assembly, maintaining uniformity and extending the lifespan of the power storage cell by ensuring consistent electrolyte distribution.
Implementation Method 1
In each of the welding portions, micropores of the separator are closed and therefore the electrolyte solution cannot pass therethrough
Data Source
AI summary
A power storage cell includes: an electrode assembly. The electrode assembly includes a plurality of positive electrodes and a plurality of negative electrodes disposed side by side in a thickness direction, and a separator. The electrode assembly has a shape longer in a width direction. The electrode assembly includes an upper portion, a bottom portion, a first end portion, and a second end portion. A first welding portion is formed in the first end portion. A second welding portion is formed in the second end portion. A third welding portion in contact with the first welding portion and a fourth welding portion in contact with the second welding portion are formed in the bottom portion. The third welding portion and the fourth welding portion are disposed at an interval with a central portion of the bottom portion being interposed between the third welding portion and the fourth welding portion.