Li-Ion Battery Electrode Interlayer for High-Density Electrolyte Permeation

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Solution Overview

Problem

Lithium ion secondary batteries face issues with reduced energy density and increased resistance due to high electrode density, which affects their performance and durability, particularly in applications requiring high energy storage like BEVs and PHEVs.

Innovation Solution

Incorporating an electroconductive layer with solid electrolyte particles and electroconductive particles between the current collector and the electrode active material layer, forming a solid electrolyte-electroconductive particle complex, which enhances electrolyte solution permeability and retention, maintaining electrical conductivity and preventing oxide coating film formation on the current collector.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the density of the electrode is increased to attain high energy density, then the energy density is improved, but the impregnation property of the electrolyte solution is reduced

Engineering Contradiction:
Improveenergy densityVSAvoidimpregnation property
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

A coating film containing a specific compound is applied to the current collector surface to act as an intermediary layer. This coating film facilitates electrolyte solution penetration while accommodating the high packing density of the active material, thereby resolving the contradiction between high energy density and good impregnation property

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The coating film on the current collector is designed with porous structure or specific morphology that allows electrolyte solution to penetrate through the dense electrode structure, enabling both high packing factor and adequate electrolyte impregnation

Inventive Principle:
Principle #31Porous materials

2Quantity of substance

If the density of the electrode is increased to attain high energy density, then the energy density is improved, but the time required for electrode production is increased

Engineering Contradiction:
Improveenergy densityVSAvoidelectrode production time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The coating film is pre-formed on the current collector before the active material is applied. This preliminary action creates a ready-made pathway for electrolyte penetration, reducing the time needed for subsequent electrolyte impregnation and electrode formation processes

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If the density of the electrode is increased to attain high energy density, then the energy density is improved, but voltage variance during aging occurs and durability deteriorates

Engineering Contradiction:
Improveenergy densityVSAvoiddurability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The coating film on the current collector serves as a protective intermediary that ensures uniform electrolyte distribution and stable electrical contact, reducing voltage variance during aging and improving the durability of high-density electrodes

Inventive Principle:
Principle #24Intermediary (Mediator)

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 increases the volume energy density of the battery, improves charge and discharge characteristics, and extends cycle life by maintaining high output and reducing resistance, even at high packing densities, thus addressing the challenges of reduced output and capacity degradation.

Implementation Method 1

the electrode includes an electroconductive layer containing solid electrolyte particles and electroconductive particles, between the current collector and the electrode active material layer

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 2

when an electrolyte salt is disposed in the vicinity of a current collector in an electrode for a lithium ion secondary battery, a fluoride-based coating film is formed on the surface of the current collector and thereby the formation of an oxide coating film on the current collector is suppressed

Methodology Applied
Scientific EffectOxidation prevention: Oxidation

Implementation Method 3

the electrode includes an electroconductive layer containing solid electrolyte particles and electroconductive particles

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS11894541B2Electrode for lithium ion secondary battery, and lithium ion secondary battery
Publication Date: 2024.02.06 HONDA MOTOR CO LTD

AI summary

Provided are an electrode for a lithium ion secondary battery, and a lithium ion secondary battery, in which a reduction in the permeability of an electrolyte solution and an increase in resistance even when the density of the electrode is increased, can be suppressed.In the electrode for a lithium ion secondary battery, a layer in which the diffusion rate of an electrolyte solution is greater than in an active material layer is disposed between a current collector and an active material layer.Specifically, the electrode for a lithium ion secondary battery includes a current collector, and an electrode active material layer containing an electrode active material, the electrode active material layer being formed on at least one side of the current collector, in which an electroconductive layer containing solid electrolyte particles and electroconductive particles is disposed between the current collector and the electrode active material layer.