Lithium-ion Battery Electrode Porous Structure

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Solution Overview

Problem

Layered crystal electrode active materials in lithium-ion batteries have low active material utilization and capacity due to parallel orientation of intercalation layers with the current collector, hindering the insertion/extraction of lithium ions.

Innovation Solution

Creating an electrode active material layer with through holes that expose cross-sectional portions of the layered crystal, allowing for facilitated lithium ion insertion/extraction, and using ion etching and heat treatment to enhance crystal orientation and mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the electrode active material layer is made from layered crystal with intercalation layers oriented parallel to the current collector, then the crystal structure is stable and easy to manufacture, but the insertion/extraction of Li ions is hindered resulting in low active material utilization and low capacity

Engineering Contradiction:

Improveease of manufactureVSAvoidactive material utilization

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The electrode active material layer is segmented into multiple granular particles instead of a continuous layered structure. This segmentation creates numerous exposed crystal surfaces and interlayer spaces, allowing electrolyte penetration and Li ion insertion/extraction throughout the material, thereby resolving the contradiction between manufacturing simplicity and active material utilization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The electrode active material layer is designed with a porous structure formed by granular particles with interstitial spaces. This porosity enables electrolyte access to internal crystal surfaces and facilitates Li ion transport, transforming the dense parallel-layered structure into an open architecture that maintains ease of manufacture while dramatically improving active material utilization.

Inventive Principle:

Principle #31Porous materials

2Strength

If the electrode active material layer is made from layered crystal with intercalation layers oriented parallel to the current collector, then the structural integrity is maintained, but the capacity and output current of the battery are limited

Engineering Contradiction:

Improvestructural integrityVSAvoidbattery output

Core Design Contradiction:

StrengthVSPower

Solution Approach 1:

Dividing the electrode material into granular particles maintains structural integrity at the particle level while creating numerous exposed surfaces and interlayer spaces. This segmentation enables simultaneous Li ion insertion/extraction at multiple sites, dramatically increasing battery capacity and output current without compromising the overall structural stability of the electrode.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from a two-dimensional parallel-layered structure to a three-dimensional granular porous structure. This dimensional change exposes crystal surfaces and interlayer spaces in multiple directions, enabling multidirectional Li ion transport and significantly enhancing battery power while maintaining structural integrity through the granular architecture.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 the active material utilization and capacity of lithium-ion batteries by enabling better lithium ion insertion/extraction while maintaining mechanical strength, resulting in enhanced battery performance.

Implementation Method 1

Layered crystal such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2) and graphite is able to increase an electrode reaction through insertion/extraction (intercalation/deintercalation) of lithium ions within the layer

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Implementation Method 2

an inner wall of each of the plurality of hole portions has preferably been subjected to ion etching treatment

Methodology Applied

Scientific EffectIon etching: Ion Beam

Data Source

PatentUS9231247B2Electrode active material layer, electrode body, lithium-ion secondary battery, and method of producing electrode active material layer

Publication Date: 2016.01.05 SEIKO EPSON CORP

AI summary

An electrode active material layer for a lithium-ion secondary battery is formed from an electrode active material of layered crystal. The electrode active material having layered crystal is oriented in a layer direction of the electrode active material layer, and a plurality of through holes are formed from the surface of the electrode active material layer. The diameter of the through holes is preferably 10 μm to 5000 μm inclusive.