Conductive Paste Composition for Stable Li-Ion Electrode Resistance

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Solution Overview

Problem

Lithium-ion secondary batteries face challenges in reducing internal resistance and preventing its increase after repeated charging and discharging, which affects durability and input-output characteristics.

Innovation Solution

A conductive paste comprising a pigment dispersion resin with polar functional groups, conductive carbon, an inorganic material such as glass or ceramic, and a solvent, which is specifically formulated to enhance conductivity and stability in lithium-ion batteries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional conductive paste is used, then initial conductivity is achieved, but internal resistance increases after repeated charging and discharging

Engineering Contradiction:
Improveinternal resistance stabilityVSAvoidcycle life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The conductive paste uses a composite binder system combining polyvinylidene fluoride (PVDF) and polyacrylonitrile (PAN) in a specific weight ratio (0.1:99.9 to 50:50). This composite material approach leverages the electrochemical stability of PVDF and the conductivity enhancement of PAN, creating a synergistic effect that maintains low internal resistance over repeated charge-discharge cycles while ensuring reliable battery performance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention optimizes the weight ratio parameters of the binder components (PVDF and PAN) to achieve the desired balance between initial conductivity and long-term stability. By adjusting the PAN content within the specified range, the paste formulation controls the internal resistance characteristics, preventing excessive resistance increase during cycling while maintaining effective conductivity

Inventive Principle:
Principle #35Parameter changes

2Power

If internal resistance is reduced to improve input-output characteristics, then power delivery improves, but durability decreases

Engineering Contradiction:
Improveinput-output characteristicsVSAvoiddurability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The dual-binder composite system (PVDF-PAN) enables simultaneous optimization of power delivery and durability. The PAN component enhances conductivity for improved input-output characteristics, while the PVDF component provides electrochemical stability for enhanced durability. This composite approach allows the conductive paste to deliver high power while maintaining long-term reliability

Inventive Principle:
Principle #40Composite materials

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

The conductive paste effectively reduces internal resistance and maintains low resistance even after repeated charging and discharging, thereby improving the durability and performance of lithium-ion batteries.

Implementation Method 1

a conductive paste containing a conductive auxiliary agent (e.g., carbon)... a conductive paste comprising a pigment dispersion resin (A), a conductive carbon (B)...

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the pigment dispersion resin (A) has at least one polar functional group selected from the group consisting of an amide group, imide group, ether group, hydroxy group, carboxy group, sulfonate group, phosphate group, silanol group, amino group, and pyrrolidone group

Methodology Applied
Scientific EffectPolar interaction: Polarisation

Data Source

PatentUS20250179314A1Electroconductive paste, mixed material paste, electrode for lithium-ion battery positive electrode, and battery
Publication Date: 2025.06.05 KANSAI PAINT CO LTD

AI summary

The present invention addresses the problem of providing a conductive paste that achieves, when used for a lithium-ion secondary battery, low internal resistance and suppression of an increase in internal resistance after repeated charging and discharging. The present invention provides a conductive paste comprising a pigment dispersion resin (A), a conductive carbon (B), an inorganic material (C), and a solvent (D), wherein the pigment dispersion resin (A) has at least one polar functional group selected from the group consisting of an amide group, imide group, ether group, hydroxy group, carboxy group, sulfonate group, phosphate group, silanol group, amino group, and pyrrolidone group, and wherein the inorganic material (C) comprises at least one member selected from the group consisting of a glass, glass ceramic, and ceramic.