Functional Current Collector Layer for High-Nickel Battery Safety

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Solution Overview

Problem

Rechargeable lithium batteries face safety issues due to the low thermal safety of high nickel positive electrode materials, which can lead to battery deterioration, increased volume and weight, and reduced energy density, as well as acting as resistors, compromising battery performance.

Innovation Solution

A current collector for rechargeable lithium batteries is introduced, featuring a substrate with a functional layer comprising a flame retardant, conductive material, and binder, which improves safety, prevents deterioration, and minimizes energy density loss by enhancing adhesion and conductivity between the substrate and electrode active material layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If high nickel positive electrode material is used to achieve high energy density, then energy density is improved, but thermal safety deteriorates

Engineering Contradiction:

Improveenergy densityVSAvoidthermal safety

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

A functional layer is introduced as an intermediary between the high nickel positive electrode material and the electrolyte. This functional layer contains flame retardant particles that act as a mediator to suppress thermal runaway reactions while maintaining ionic conductivity for battery operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The functional layer is constructed as a composite material system combining flame retardant particles (such as melamine polyphosphate), conductive materials (such as acetylene black), and binder materials (such as polyvinylidene fluoride). This composite structure provides both thermal safety and electrochemical performance.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If safety functional material is introduced to improve thermal runaway and battery safety, then safety is improved, but volume and weight increase

Engineering Contradiction:

Improvebattery safetyVSAvoidbattery weight

Core Design Contradiction:

Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The functional layer is applied as a thin film coating on the positive electrode, providing safety functionality without adding significant volume or weight. The thin film structure ensures minimal impact on battery dimensions while delivering effective thermal runaway suppression.

Inventive Principle:

Principle #30Flexible shells and thin films

3Object-affected harmful factors

If safety functional material is introduced to improve thermal runaway and battery safety, then safety is improved, but energy density decreases

Engineering Contradiction:

Improvebattery safetyVSAvoidenergy density

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The functional layer is designed as a thin coating that provides safety functionality with minimal thickness, thereby reducing the volume occupied by non-active materials and minimizing the impact on energy density.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The functional layer is applied as a surface coating on the positive electrode, providing safety functionality without replacing active materials. This approach maintains the energy-storing capacity of the electrode while adding protective functionality.

Inventive Principle:

Principle #26Copying

4Object-affected harmful factors

If safety functional material is introduced to improve thermal runaway and battery safety, then safety is improved, but battery characteristics deteriorate due to increased resistance

Engineering Contradiction:

Improvebattery safetyVSAvoidbattery characteristics

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The functional layer is constructed as a composite material system combining flame retardant particles, conductive materials, and binder materials. This composite structure ensures both thermal safety and adequate ionic conductivity for battery operation.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The functional layer's composition and structure are optimized to balance flame retardancy and ionic conductivity. By controlling particle size, distribution, and matrix composition, the layer provides safety functionality while maintaining acceptable resistance characteristics for battery performance.

Inventive Principle:

Principle #35Parameter changes

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 solution effectively enhances the safety and electrochemical characteristics of rechargeable lithium batteries by improving thermal stability, preventing deterioration, and maintaining energy density, as demonstrated by improved self-extinguishing properties and charge/discharge profiles.

Implementation Method 1

the functional layer includes a flame retardant

Methodology Applied

Scientific EffectFlame retardancy:

Implementation Method 2

the functional layer includes a flame retardant, a conductive material, and a binder

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS20240413349A1Electrode current collector for rechargeable lithium battery, electrode, and rechargeable lithium battery including same

Publication Date: 2024.12.12 SAMSUNG SDI CO LTD

AI summary

A current collector for a rechargeable lithium battery according to an embodiment includes a substrate; and a functional layer on the substrate, wherein the functional layer includes a flame retardant, a conductive material, and a binder.