Secondary Battery Electrode Binder Zoning for Adhesion and Conductivity
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Solution Overview
Problem
Existing secondary battery electrodes face challenges in securing high inter-particle adhesion force and adhesion force between the active material layer and the current collector, leading to stability and performance issues due to insufficient binder distribution, which can result in particle detachment and decreased conductivity.
Innovation Solution
The electrode design incorporates a current collector with a controlled distribution of binder, forming network and blank regions to enhance adhesion force, allowing for a higher active material content while maintaining a small binder amount, by adjusting the ratio and distribution of these regions on the current collector surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a larger amount of binder is introduced into the active material layer, then adhesion force is improved, but battery performance deteriorates due to increased electrode resistance and decreased conductivity
Solution Approach 1:
The patent applies local quality by creating a binder-rich interface layer at the boundary between the active material layer and current collector, while maintaining lower binder content in the bulk active material layer. This localized concentration of binder at the interface provides strong adhesion force without compromising the overall conductivity and performance of the electrode, as the bulk material retains its optimal composition for electrical performance.
2Stability of the object's composition
If binder content is increased to secure adhesion force, then adhesion between particles and current collector improves, but active material ratio decreases leading to higher electrode resistance
Solution Approach 1:
The patent segments the binder distribution into two distinct zones: an interface layer with high binder content for adhesion, and a bulk layer with lower binder content for optimal electrical performance. This segmentation allows the binder to perform its adhesion function locally at the interface without unnecessarily reducing the active material ratio in the bulk, thereby maintaining both stability and quantity of active material.
3Reliability
If more binder is used to prevent particle detachment, then adhesion force increases, but conductivity decreases due to higher electrode resistance
Solution Approach 1:
The patent implements local quality by concentrating binder specifically at the interface layer where particle stability is needed, rather than uniformly distributing it throughout the bulk material. This localized approach ensures particle stability at the critical interface region while minimizing the binder's negative impact on conductivity in the bulk active material layer, thus reducing overall electrode resistance.
Data Source
AI summary
An electrode has a current collector and an active material layer, which can provide an electrode capable of ensuring high levels of adhesion force between particles, and adhesion force between the active material layer and the current collector compared with a binder content in the active material layer. An electrochemical element and a secondary battery having the electrode are also provided.