Layered Battery Electrode Binder Profile for Electrolyte Permeability
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Solution Overview
Problem
Existing non-aqueous electrolyte secondary batteries face issues with non-uniform electrode reactions and reduced capacity due to electrolyte solution blockage at the electrode ends, caused by high binder concentrations at the cutting sites during manufacturing, leading to missing parts and potential short-circuiting.
Innovation Solution
A layered electrode structure with a first layer, a second layer, and a third layer, where the third layer has a higher binder content than the first layer, specifically over the end portions, and the second layer has a lower binder content than the first layer, allowing for improved electrolyte permeability and reduced missing parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the binder concentration is increased at the end portion of the electrode to suppress missing parts during manufacturing, then the missing part of the mixture layer is suppressed, but the electrolyte solution return is blocked, resulting in non-uniform electrode reaction and reduced capacity
Solution Approach 1:
The electrode is divided into multiple regions with different binder concentrations: a first region (end portion) with higher binder concentration to prevent missing parts, and a second region (central portion) with lower binder concentration to maintain electrolyte permeability. This spatial segmentation allows each region to fulfill its specific function without compromising the other.
Solution Approach 2:
Different parts of the electrode are assigned different binder concentrations according to their functional requirements. The end portion has higher binder content for structural integrity during manufacturing, while the central portion has lower binder content for electrolyte flow, creating local quality variations that optimize both manufacturing precision and cycle characteristics.
2Manufacturing precision
If the binder concentration is uniformly increased across the entire electrode, then the missing part of the mixture layer is suppressed, but the electrolyte solution permeability is reduced throughout, causing non-uniform electrode reaction
Solution Approach 1:
The electrode structure is segmented into regions with different binder concentrations, allowing the end portions to have high binder content for missing part suppression while the central region maintains low binder content for electrolyte permeability, thus resolving the contradiction between manufacturing precision and electrolyte flow.
Solution Approach 2:
The binder concentration is made non-uniform across the electrode, with localized high concentration at the ends for structural stability and localized low concentration in the center for electrolyte permeability, optimizing both manufacturing and operational performance.
Data Source
AI summary
A non-aqueous electrolyte secondary battery according to one embodiment, wherein a mixture layer of an electrode has a first layer formed on a core body, and second and third layers formed on the first layer. The first, second, and third layers contain a binding agent, and the third layer is formed on at least a part of an end of the electrode. The content of the binding agent in the third layer is higher than the content of the binding agent in the first layer, and is greater than 0.8 mass % and less than 2.0 mass %.