Layered Battery Electrode Binder Gradient for Adhesion and Low Resistance

Solution Overview

Problem

Lithium secondary batteries face issues with adhesion force between the electrode and the active material layer, leading to increased resistance on the outer interface of the active material layer, which deteriorates battery performance.

Innovation Solution

The development of an electrode with multiple active material layers, where at least one layer includes a binder with a specific weight content of 1.0 to 1.7 parts per 100 parts of the total active material layers, to enhance adhesion and reduce interfacial resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the binder content is increased to improve adhesion force between the current collector and the active material layer, then the adhesion force increases, but the resistance on the upper interface of the active material layer increases and battery characteristics at high rate deteriorate

Engineering Contradiction:

Improveadhesion forceVSAvoidbattery characteristics at high rate

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies local quality by creating a binder concentration gradient within the active material layer. The binder content is higher near the current collector interface to ensure strong adhesion, and gradually decreases toward the upper interface to maintain low resistance. This spatial variation in binder distribution allows simultaneous optimization of both adhesion force and electrical performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the binder content parameter from a uniform distribution to a gradient distribution. By controlling the binder content to be 1.0-3.0 wt% near the current collector and decreasing toward the upper interface, the patent optimizes both adhesion strength and interfacial resistance, resolving the contradiction between these two parameters.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the binder content is decreased to reduce resistance on the upper interface of the active material layer, then the resistance decreases, but the adhesion force between the current collector and the active material layer decreases

Engineering Contradiction:

Improvebattery characteristics at high rateVSAvoidadhesion force

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by creating a binder concentration gradient within the active material layer. The binder content is higher near the current collector interface to ensure strong adhesion, and gradually decreases toward the upper interface to maintain low resistance. This spatial variation in binder distribution allows simultaneous optimization of both adhesion force and electrical performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the binder content parameter from a uniform distribution to a gradient distribution. By controlling the binder content to be 1.0-3.0 wt% near the current collector and decreasing toward the upper interface, the patent optimizes both adhesion strength and interfacial resistance, resolving the contradiction between these two parameters.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a single active material layer is used to simplify the electrode structure, then the device complexity decreases, but the adhesion force and interfacial resistance cannot be simultaneously optimized

Engineering Contradiction:

Improveelectrode structureVSAvoidadhesion force and interfacial resistance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies segmentation by dividing the single active material layer into multiple sub-layers with different binder contents. The lower layer (near current collector) has higher binder content (1.0-3.0 wt%) for strong adhesion, while the upper layer has lower binder content (0.5-2.0 wt%) for low resistance. This segmentation allows simultaneous optimization of adhesion and electrical performance without excessive complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by creating a binder concentration gradient within the active material layer. The binder content is higher near the current collector interface to ensure strong adhesion, and gradually decreases toward the upper interface to maintain low resistance. This spatial variation in binder distribution allows simultaneous optimization of both adhesion force and electrical performance.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250096245A1Electrode and lithium secondary battery comprising same

Publication Date: 2025.03.20 SAMSUNG SDI CO LTD

AI summary

Provided an electrode for secondary batteries, the electrode including: a substrate; and a plurality of active material layers arranged on the substrate and each including an active material, wherein at least one of the plurality of active material layers includes a binder, and a content of the binder is about 1.0 part by weight to about 1.7 parts by weight based on 100 parts by weight of a total weight of the plurality of active material layers.