Lithium Battery Negative Electrode Self-Assembly for Multi-Layer Adhesion
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Solution Overview
Problem
The existing methods for manufacturing multi-layer electrodes for lithium secondary batteries are complex and prone to degradation of interfacial adhesion, requiring multiple steps and individual slurry preparations, which increases costs and reduces efficiency.
Innovation Solution
A negative electrode with a multi-layer structure is created using a single application and drying step by incorporating two or more types of negative electrode active materials with different water contact angles, allowing for self-assemblage and improved adhesion without additional processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a multi-layer electrode is manufactured using conventional methods with multiple slurry applications, then the electrode structure can be formed, but the manufacturing process becomes complicated and interfacial adhesion degrades
Solution Approach 1:
The patent combines multiple active materials into a single slurry formulation, eliminating the need for multiple separate coating steps. The slurry contains a mixture of graphite and silicon-based active materials along with binder and conductive agents, which are all applied in one coating operation to form the multi-layer electrode structure.
Solution Approach 2:
The patent employs self-assembly mechanisms where the different active materials automatically segregate into distinct layers within the single applied slurry coat. The binder and conductive materials also self-distribute to ensure proper adhesion and conductivity at interfaces, eliminating the need for manual intervention in creating the multi-layer structure.
2Shape
If multiple slurry applications are used to create multi-layer electrodes, then layer structure is achieved, but manufacturing cost increases and productivity decreases
Solution Approach 1:
The patent merges multiple coating operations into a single slurry application step. By formulating a comprehensive slurry containing all necessary active materials, binders, and conductive agents, the manufacturing process is streamlined from multiple sequential steps to one efficient coating operation, significantly improving productivity.
Solution Approach 2:
The patent performs preliminary mixing and formulation of the slurry to pre-establish the correct composition and distribution of all components. This preliminary preparation ensures that when the slurry is applied in a single step, the multi-layer structure forms automatically without requiring subsequent processing steps, thereby enhancing manufacturing efficiency.
3Shape
If conventional multi-layer electrode methods are used, then electrode structure is formed, but interfacial adhesion deteriorates
Solution Approach 1:
The patent applies local quality by providing different material compositions at different locations within the electrode structure. The slurry formulation ensures that binder and conductive materials are present at the interfaces between different active material layers, creating locally optimized zones for adhesion and conductivity where needed most.
Solution Approach 2:
The patent uses binder materials as intermediaries between different active material layers. These binders are specifically selected to provide strong adhesion at the interfaces between graphite and silicon-based materials, preventing degradation and maintaining structural integrity during battery cycling.
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 approach simplifies the manufacturing process, enhances battery performance by improving output and life characteristics, and reduces costs by eliminating the need for multiple slurry applications, while maintaining or exceeding the performance of conventional multi-layered electrodes.
Implementation Method 1
When two or more types of negative electrode active materials having different surface properties are incorporated in negative electrode slurry, interlayer separation occurs from the upper side to the lower side of the slurry in order of smallest water contact angle to largest water contact angle, and thus a multi-layered negative electrode can be formed according to self-assemblage
Implementation Method 2
applying the interlayer separated slurry for a negative electrode mixture layer to at least one surface of a negative electrode current collector, followed by drying, to form a first negative electrode mixture layer
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
Disclosed is a negative electrode for a lithium secondary battery which includes: a negative electrode current collector; a first negative electrode mixture layer positioned on at least one surface of the negative electrode current collector and including a first negative electrode active material, a polymer binder and a conductive material; and a second negative electrode mixture layer positioned on the top surface of the first negative electrode mixture layer and including a second negative electrode active material, a polymer binder and a conductive material, wherein the second negative electrode active material has a smaller water contact angle as compared to the first negative electrode active material, and at least one of the first negative electrode active material and the second negative electrode active material is surface-modified.