Anode Particle Orientation for High-Density Li-Ion Cycle Stability

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Solution Overview

Problem

Lithium ion batteries face challenges in achieving high energy density while maintaining cycle life and safety due to excessive compacted density of anode particles, leading to uneven solid electrolyte interface formation, poor electrolyte infiltration, increased surface resistance, and risk of lithium precipitation and battery deformation.

Innovation Solution

The lithium ion battery anode features an anode active material layer with particles oriented at specific tilt angles (0°<θ1≤20°, 20°<θ2<70°, and 70°<θ3≤90°) and varying particle sizes, achieving a compacted density of 1.70 g/cm³ to 1.90 g/cm³, which allows for isotropic properties and improved lithium ion intercalation/deintercalation, reducing expansion and deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the compacted density of the anode is increased to improve energy density, then the energy density of lithium ion batteries is improved, but the anode particles break up, resulting in uneven solid electrolyte interface formation, poor electrolyte infiltration, increased surface resistance, and risk of lithium precipitation and battery deformation

Engineering Contradiction:

Improveenergy densityVSAvoidcycle performance

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies local quality by creating different particle orientations in different regions of the anode. Specifically, particles are oriented with their c-axis at angles of 0°-30° relative to the current collector surface in certain regions, while maintaining other orientations in different regions. This local variation in particle orientation allows different areas to have optimized properties for either energy density or cycle stability, resolving the contradiction between high compacted density and particle integrity.

Inventive Principle:

Principle #3Local quality

2Use of energy by moving object

If the compacted density of the anode is increased to improve energy density, then the energy density of lithium ion batteries is improved, but electrolyte infiltration is poor, leading to increased surface resistance and lithium precipitation

Engineering Contradiction:

Improveenergy densityVSAvoidsurface resistance

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent utilizes porous materials by controlling the particle orientation distribution to create an optimized pore structure within the anode. The specific orientation arrangement (c-axis at 0°-30° to current collector) creates interconnected void spaces that facilitate electrolyte penetration while maintaining high compacted density. This porous structure allows sufficient electrolyte infiltration to prevent lithium precipitation and reduce surface resistance, even at high energy density.

Inventive Principle:

Principle #31Porous materials

3Use of energy by moving object

If the compacted density of the anode is increased to improve energy density, then the energy density of lithium ion batteries is improved, but battery deformation occurs

Engineering Contradiction:

Improveenergy densityVSAvoidbattery deformation

Core Design Contradiction:

Use of energy by moving objectVSShape

Solution Approach 1:

The patent applies asymmetry by creating an non-uniform particle orientation distribution within the anode structure. Rather than random or uniform orientation, particles are deliberately arranged with c-axes at specific asymmetric angles (0°-30° to current collector) in certain regions. This asymmetric orientation pattern creates internal stress distribution that compensates for expansion forces during lithium insertion, preventing battery deformation while maintaining high compacted density for high energy density.

Inventive Principle:

Principle #4Asymmetry

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

This configuration enhances energy density, cycle performance, and rapid charge/discharge capabilities while minimizing lithium precipitation and battery deformation, ensuring stable and efficient lithium ion battery operation.

Implementation Method 1

improved lithium ion intercalation/deintercalation

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3872904B1Negative electrode and electrochemical apparatus containing negative electrode

Publication Date: 2024.07.31 NINGDE AMPEREX TECHNOLOGY LTD

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AI summary

The present application relates to an anode comprising a current collector and an anode active material layer on the current collector. The anode active material layer comprises first oriented particles having a first tilt angle θ1 inclined with respect to the direction of the current collector, and second oriented particles having a second tilt angle θ2 inclined with respect to the direction of the current collector, wherein the first tilt angle θ1 and the second tilt angle θ2 are different and both not greater than 70°. Further provided is an electrochemical device comprising the anode.