Lithium Secondary Battery Grain-Size Matching for High Energy Density

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Solution Overview

Problem

Existing lithium secondary batteries face limitations in increasing energy density and efficiency within a limited space due to the challenges of high nickel content in positive electrode materials and large lithium consumption by non-carbon-based negative electrode materials, leading to stability issues and irreversible capacity loss.

Innovation Solution

Regulating the size of crystal grains in both the positive and negative electrode active materials, specifically using a lithium transition metal compound with controlled nickel, cobalt, and manganese composition, and a silicon carbon composite with Si crystal grains, to maintain a stable crystal structure and reduce swelling and cycle performance deterioration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If nickel content in positive electrode active material is increased to increase capacity, then energy density is improved, but thermal stability deteriorates and gas generation increases

Engineering Contradiction:

ImprovecapacityVSAvoidthermal stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent uses a nickel-cobalt-manganese (NCM) composite material for the positive electrode active material. By combining multiple transition metals with different properties, the material achieves high capacity from nickel while cobalt and manganese provide thermal stability and structural integrity, preventing gas generation and deterioration during electrochemical reactions

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes the compositional parameters of the NCM material, specifically controlling the ratios of nickel, cobalt, and manganese elements. By adjusting these parameters, the material achieves optimal balance between high capacity (from high nickel content) and thermal stability (maintained through controlled cobalt and manganese content)

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If non-carbon-based negative electrode materials are used to increase capacity, then energy density is improved, but irreversible capacity loss increases due to large lithium consumption

Engineering Contradiction:

ImprovecapacityVSAvoidirreversible capacity loss

Core Design Contradiction:

Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent optimizes the particle size parameters of the silicon carbon composite negative electrode material. By controlling particle size within specific ranges, the material achieves high capacity while reducing lithium consumption during initial charging, thereby minimizing irreversible capacity loss and improving initial efficiency

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If battery size is increased to improve energy density, then capacity is improved, but space constraints are violated

Engineering Contradiction:

Improveenergy densityVSAvoidbattery size

Core Design Contradiction:

Quantity of substanceVSVolume of moving object

Solution Approach 1:

The patent optimizes multiple parameters including particle sizes of both positive and negative electrode materials, as well as their compositional ratios. These parameter optimizations enable higher capacity materials to be packed more efficiently, achieving improved energy density without excessive increase in battery volume

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

Improves rapid charging performance, efficiency, service life, and energy density by stabilizing the lithium diffusion pathway and reducing stress during lithiation/delithiation processes, thereby enhancing battery performance within confined spaces.

Implementation Method 1

The lithium secondary battery generates electric energy by oxidation and reduction reactions during intercalation and deintercalation of lithium ions

Methodology Applied

Scientific EffectOxidation and reduction reactions: Redox Reactions

Implementation Method 2

Methodology Applied

Scientific EffectCrystal structure stabilization: Crystallisation

Implementation Method 3

intercalation and deintercalation of lithium ions

Methodology Applied

Scientific EffectLithium ion diffusion: Diffusion

Data Source

PatentUS12573614B2Lithium secondary battery, battery pack and electronic device including same

Publication Date: 2026.03.10 LG ENERGY SOLUTION LTD

AI summary

Disclosed are a lithium secondary battery, a battery pack and an electronic device. The lithium secondary battery includes: a positive electrode comprising a positive electrode active material; a negative electrode comprising a negative electrode active material; a separator between the positive electrode and the negative electrode; and an electrolyte, wherein the positive electrode active material comprises a lithium transition metal compound comprising nickel (Ni), cobalt (Co) and manganese (Mn), wherein the lithium transition metal compound comprises a form of single particles having at least one of a single primary particle or an aggregate of 2 or more and 30 or less of primary particles, wherein the single particles comprise crystal grains of the lithium transition metal compound therein, wherein the negative electrode active material comprises a silicon carbon composite having Si crystal grains therein, and wherein the size of the Si crystal grains of the silicon carbon composite is 10% or less of the size of the crystal grains of the lithium transition metal compound.