Single-Layer Nonwoven Thermal Barrier for Battery Safety

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Solution Overview

Problem

Existing thermal barrier elements for battery assemblies, such as those used in electric vehicles, often require multiple layers of inorganic materials to slow down thermal runaway events, which can be cumbersome and inefficient.

Innovation Solution

A single-layer thermal runaway barrier composed of a nonwoven fibrous thermal insulation with inorganic fibers and thermally insulative particles, optionally encapsulated with an organic layer, is used to mitigate thermal runaway events in battery assemblies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If multiple layers of inorganic materials are used as thermal barrier elements, then thermal insulation performance is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvethermal insulation performanceVSAvoidnumber of layers
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent combines multiple inorganic materials (fibrous inorganic material, particulate inorganic material, and sheet-like inorganic material) into a single integrated nonwoven structure. This merging approach maintains the thermal insulation benefits of multiple materials while eliminating the complexity of assembling multiple separate layers, directly resolving the contradiction between thermal performance and device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention creates a composite inorganic nonwoven material that integrates different inorganic components (fibers, particles, and sheets) with complementary thermal properties. This composite structure achieves superior thermal insulation performance compared to single-layer approaches while maintaining a simple single-layer configuration, thereby resolving the contradiction between insulation effectiveness and structural complexity

Inventive Principle:
Principle #40Composite materials

2Temperature

If multiple layers of inorganic materials are used as thermal barrier elements, then thermal insulation performance is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improvethermal insulation performanceVSAvoidmanufacturing process simplicity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent merges multiple inorganic material types into a single manufacturable nonwoven layer, eliminating the need for separate manufacturing and assembly processes for multiple layers. This approach maintains high thermal insulation performance while significantly simplifying the manufacturing process, directly addressing the contradiction between thermal performance and ease of manufacture

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention changes the structural parameters of the thermal barrier by creating a three-dimensional nonwoven architecture that integrates multiple material functions within a single layer. This parameter change allows the material to achieve multi-layer thermal performance through a single manufacturing process, resolving the contradiction between insulation effectiveness and manufacturing simplicity

Inventive Principle:
Principle #35Parameter changes

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

The single-layer barrier effectively slows down thermal runaway events by providing thermal insulation and gas venting capabilities, enhancing safety and efficiency in battery assemblies.

Implementation Method 1

a nonwoven fibrous thermal insulation comprising a fiber matrix of inorganic fibers, thermally insulative inorganic particles dispersed within the fiber matrix

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

a binder dispersed within the fiber matrix so as to hold together the fiber matrix

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4386122B1Battery cell thermal runaway barrier
Publication Date: 2025.11.05 3M INNOVATIVE PROPERTIES CO
  • EP4386122B1 patent drawingFigure 1~2
  • EP4386122B1 patent drawingFigure 3~4
  • EP4386122B1 patent drawingFigure 5

AI summary

A thermal runaway barrier for at least significantly slowing down a thermal runaway event within a battery assembly. The thermal runaway barrier consisting essentially of a single-layer of a nonwoven fibrous thermal insulation comprising a fiber matrix of inorganic fibers, thermally insulative inorganic particles dispersed within the fiber matrix, and a binder dispersed within the fiber matrix so as to hold together the fiber matrix. An optional organic encapsulation layer may also be used to encapsulate the nonwoven fibrous thermal insulation.