Battery Electrode Binder Zoning for Adhesion and Low Resistance

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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, often resulting in particle detachment, reduced performance, and increased electrode resistance due to insufficient binder distribution.

Innovation Solution

The electrode design involves controlling the distribution of the binder in the active material layer adjacent to the current collector, optimizing the binder's occupied area ratio and particle diameter ratio to enhance adhesion forces, even with a small binder content, through careful composition of the slurry and surface characteristics of the current collector.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a larger amount of binder is introduced into the active material layer, then higher adhesion force is secured, but the ratio of active material decreases causing deterioration of battery performance

Engineering Contradiction:

Improveadhesion forceVSAvoidbattery performance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The binder is selectively distributed to the lower portion of the active material layer adjacent to the current collector, creating a localized high-adhesion zone where it is most needed for particle support and electron transfer, while maintaining high active material content in the upper portions for optimal electrochemical performance

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The active material layer is divided into different regions with different binder concentrations - a lower portion with higher binder content for adhesion and an upper portion with lower binder content for electrochemical activity, allowing each region to optimize its function

Inventive Principle:

Principle #1Segmentation

2Reliability

If the adhesion force between particles in the active material layer is insufficient, then particle detachment occurs, but increasing binder content increases electrode resistance

Engineering Contradiction:

Improveparticle stabilityVSAvoidelectrode resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Binder is concentrated in the lower portion of the active material layer where particle stability is critical, providing localized reinforcement without adding excess binder throughout the entire layer that would increase resistance

Inventive Principle:

Principle #3Local quality

3Speed

If the adhesion force between active material layer and current collector is lowered, then electron movement speed decreases, but increasing binder content reduces active material ratio

Engineering Contradiction:

Improveelectron movement speedVSAvoidactive material ratio

Core Design Contradiction:

SpeedVSQuantity of substance

Solution Approach 1:

The binder is strategically placed in the lower portion adjacent to the current collector where it directly facilitates electron transfer between particles and the collector, ensuring high electron movement speed without sacrificing overall active material content

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20230317955A1Electrode

Publication Date: 2023.10.05 LG ENERGY SOLUTION LTD

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 comprising the electrode are also provided.