Polymer-Dispersed Positive Electrode for Battery Short-Circuit Protection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing positive electrode materials in secondary batteries with high energy density suffer from increased resistance and safety issues due to internal short circuits, leading to excessive heat generation and degradation of battery performance.

Innovation Solution

Incorporating a polymer material with a melting point or thermal decomposition temperature between 200°C and 500°C, dispersed as island-shaped regions with an average particle diameter of 50 µm or less in the positive electrode active material layer, which forms a conductive path-blocking mechanism during high temperatures to suppress short-circuit current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high energy density positive electrode materials are used, then battery energy density is improved, but internal short circuit resistance deteriorates leading to safety issues

Engineering Contradiction:

Improveenergy densityVSAvoidshort circuit resistance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The positive electrode active material layer is segmented by dispersing polymer material particles throughout it, creating multiple isolated insulating regions that block short circuit current paths while preserving the overall electrode structure and high energy density characteristics

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The polymer material acts as an intermediary substance between the positive and negative electrodes, providing thermal insulation and electrical resistance to prevent direct contact and short circuiting while allowing the high energy density materials to maintain their performance

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If high energy density positive electrode materials are used, then battery energy density is improved, but heat generation during short circuit increases

Engineering Contradiction:

Improveenergy densityVSAvoidheat generation

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The polymer material with specific melting point (200-500°C) converts the thermal energy from short circuit heating into a beneficial effect by melting and forming insulating barriers that automatically suppress further heat generation and protect the battery from thermal runaway

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If polymer material is added to positive electrode active material layer, then short circuit resistance is improved, but electrode structure complexity increases

Engineering Contradiction:

Improveshort circuit resistanceVSAvoidelectrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The polymer material is distributed as discrete particles with specific size range (0.1-10 μm) throughout the positive electrode active material layer, providing localized insulation properties where needed while maintaining the overall simplicity and integrity of the electrode structure

Inventive Principle:

Principle #3Local quality

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 approach enhances both safety and battery performance by reducing resistance and preventing excessive heat generation during internal short circuits, maintaining high energy density.

Implementation Method 1

the additive is a polymer material having a melting point or thermal decomposition temperature of 200°C or higher and 500°C or lower

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

the additive is a polymer material having a melting point or thermal decomposition temperature of 200°C or higher and 500°C or lower

Methodology Applied

Scientific EffectThermal decomposition: Decomposition (biological)

Implementation Method 3

in a cross section of the positive electrode active material layer, the polymer material forms and is dispersed as a plurality of island-shaped regions, and an average particle diameter of the polymer material is 50 μm or less

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentEP4645413A1Nonaqueous electrolyte secondary battery and positive electrode used in same

Publication Date: 2025.11.05 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

Figure 1

AI summary

A nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, a nonaqueous electrolyte, and a separator provided between the positive electrode and the negative electrode. The positive electrode includes a positive electrode current collector and a positive electrode active material layer carried on the positive electrode current collector. The positive electrode active material layer contains a positive electrode active material, a binder, and an additive. The additive is a polymer material having a melting point or thermal decomposition temperature of 200°C or higher and 500°C or lower. In a cross section of the positive electrode active material layer, the polymer material forms and is dispersed as a plurality of island-shaped regions. The average particle diameter of the polymer material is 50 µm or less.