Battery Electrode Insulating Layer for Low Internal Resistance

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Solution Overview

Problem

The increase in internal resistance of batteries is a challenge that existing technologies have not adequately addressed.

Innovation Solution

The electrode design includes a current collecting layer, an active material layer, and an insulating layer with specific porosity and particle diameter ranges, where the insulating layer overlaps minimally with the active material layer to enhance electrolyte retention and ion propagation, thereby reducing internal resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an insulating layer is added to the electrode structure, then internal resistance increase is suppressed, but device complexity increases

Engineering Contradiction:
Improveinternal resistance stabilityVSAvoidelectrode structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The insulating layer is segmented into multiple layers with different functions: a first insulating layer with specific porosity (25-70%) and particle diameter (0.5-5.0 μm) for ion transport, and a second insulating layer for additional insulation. This segmentation allows each layer to perform its specific function optimally while managing overall complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the insulating layer have different properties. The first insulating layer has controlled porosity and particle size distribution to facilitate ion transport where needed, while maintaining insulating properties where required. The overlap ratio control (0.001-30%) creates local variations in ion transport pathways.

Inventive Principle:
Principle #3Local quality

2Productivity

If insulating material particle diameter is increased, then ion propagation is enhanced, but manufacturing precision requirements increase

Engineering Contradiction:
Improveion propagation efficiencyVSAvoidparticle diameter control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent specifies a particular range for insulating material particle diameter (0.5-5.0 μm) and porosity (25-70%) to optimize ion propagation. This parameter control balances ion transport efficiency with manufacturing feasibility, avoiding both too-fine particles that would clog pores and too-coarse particles that would be difficult to manufacture consistently.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If insulating layer porosity is increased, then lithium ion flow is smoothed, but structural strength decreases

Engineering Contradiction:
Improvelithium ion flowVSAvoidinsulating layer strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The first insulating layer is designed with controlled porosity (25-70%) to create pathways for lithium ion transport. The porous structure allows ions to flow through the insulating layer while the solid matrix maintains mechanical strength. The specific porosity range balances ion conductivity with structural integrity.

Inventive Principle:
Principle #31Porous materials

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 effectively suppresses the increase in internal resistance, maintaining energy density and ensuring smooth lithium ion flow, thus improving battery performance.

Implementation Method 1

The insulating layer has a porosity of 25% or more but 70% or less

Methodology Applied
Scientific EffectPorosity: Porosity

Implementation Method 2

enhance electrolyte retention and ion propagation, thereby reducing internal resistance

Methodology Applied
Scientific EffectIon propagation: Ion Exchange

Data Source

PatentEP4704157A1Electrode and battery
Publication Date: 2026.03.04 VEHICLE ENERGY JAPAN INC
  • EP4704157A1 patent drawingFigure 1
  • EP4704157A1 patent drawingFigure 2
  • EP4704157A1 patent drawingFigure 3

AI summary

Provided is an electrode (positive electrode 100) that includes a current collecting layer (positive electrode current collecting layer 110), an active material layer (positive electrode active material layer 120), and an insulating layer (130). The active material layer (positive electrode active material layer 120) contains an active material (positive electrode active material 121) and is stacked on and bonded to the current collecting layer (positive electrode current collecting layer 110). The insulating layer (130) contains an insulating material (131) having insulating properties, and is stacked on and bonded to the active material layer (positive electrode active material layer 120). The average particle diameter (D50) of the insulating material (131) is 0.5 µm or more to 5.0 µm. The insulating layer (130) has a porosity of 25% or more but 70% or less. The insulating layer (130) and the active material layer (positive electrode active material layer 120) overlap with each other by 0.001% or more but 30% or less in a stacking direction Z.