Double Coated Negative Active Material for Lithium Battery Stress Management

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Lithium secondary batteries face challenges with excessive stress caused by volumetric expansion and shrinkage of non-carbonaceous materials during charging and discharging, leading to reduced lifespan and efficiency of the negative electrode.

Innovation Solution

A negative active material is developed with a non-carbonaceous core coated with a double layer, comprising a first metal coating layer and a second metal oxide or nitride layer, which reduces stress and enhances the battery's lifespan by inhibiting volumetric expansion and forming a stable artificial solid electrolyte interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If non-carbonaceous materials are used as negative active material, then capacity and energy density are improved, but volumetric expansion and shrinkage cause excessive stress reducing lifespan

Engineering Contradiction:

ImprovecapacityVSAvoidlifespan

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies nested doll by creating a multi-layer coating structure where an inner coating layer is embedded within an outer coating layer. The inner layer directly contacts the non-carbonaceous core to buffer volumetric expansion, while the outer layer provides additional protection, forming a nested protective system that resolves the contradiction between high capacity and lifespan

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent uses composite materials by combining different coating materials with complementary properties - the inner coating layer uses materials that accommodate volume changes, while the outer coating layer uses materials that provide structural stability and stress resistance. This composite structure allows the negative electrode to maintain both high capacity and extended lifespan

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If non-carbonaceous materials are used as negative active material, then energy density is improved, but structural integrity deteriorates due to repeated expansion and shrinkage

Engineering Contradiction:

Improveenergy densityVSAvoidstructural integrity

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies beforehand cushioning by pre-forming the inner coating layer on the non-carbonaceous core before battery operation. This layer acts as a cushion that absorbs and distributes the stress from volumetric expansion during initial charging cycles, preventing structural damage before it occurs and maintaining integrity throughout battery life

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent uses flexible shells by creating thin film coating layers that can elastically deform to accommodate the volumetric changes of the non-carbonaceous core. These flexible thin films maintain structural integrity by flexing with expansion and shrinkage rather than cracking, preserving both energy density and stability

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If double coating layer is formed to buffer stress, then lifespan is improved, but manufacturing complexity increases

Engineering Contradiction:

ImprovelifespanVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by optimizing the thickness parameters of the inner and outer coating layers to achieve effective stress buffering with minimal material. By carefully controlling layer thicknesses within specific ranges, the patent extends lifespan while keeping the manufacturing process relatively simple and avoiding excessive complexity

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 double coating layer effectively buffers stress and improves the lifespan and efficiency of lithium batteries by maintaining the structural integrity of the non-carbonaceous core, resulting in enhanced capacity retention and charging characteristics.

Implementation Method 1

A negative active material, including a non-carbonaceous core allowing doping or undoping of lithium ion; and a double coating layer formed on at least one portion of a surface of the non-carbonaceous core and including a first coating layer including a metal

Methodology Applied

Scientific EffectStress buffering: Damping

Implementation Method 2

a second coating layer including a metal oxide or a metal nitride... forming a stable artificial solid electrolyte interface

Methodology Applied

Scientific EffectArtificial solid electrolyte interface formation: Deposition (physical)

Implementation Method 3

a non-carbonaceous core allowing doping or undoping of lithium ion

Methodology Applied

Scientific EffectIon doping/undoping: Ion Exchange

Data Source

PatentUS11223040B2Negative active material and lithium battery including the same

Publication Date: 2022.01.11 SAMSUNG SDI CO LTD

AI summary

Provided are a negative active material and a lithium battery including the negative active material. The negative active material includes a non-carbonaceous core allowing doping or undoping of lithium ion; and a double coating layer formed on at least one portion of a surface of the non-carbonaceous core and including a first coating layer including a metal and a second coating layer including a metal oxide or a metal nitride.