Battery Cell Blocking Layer for Delayed Thermal Propagation

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Solution Overview

Problem

Lithium-ion battery cells are prone to thermal runaway, which can lead to rapid heat propagation and pose safety risks, especially in high-energy density cells like those containing silicon or lithium metal, due to their lower heat capacity and rapid temperature rise.

Innovation Solution

Implementing a blocking device (BLD) with a thermally stable insulating layer, comprising ceramic fibers and phase change materials, to prevent heat transfer and delay thermal propagation by absorbing heat through endothermic reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If high energy density cell materials (silicon or lithium metal) are used, then energy density is improved, but heat capacity decreases and thermal runaway risk increases

Engineering Contradiction:

Improveenergy densityVSAvoidthermal safety

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A blocking device comprising an insulating layer is introduced as an intermediary between adjacent battery cells. This insulating layer acts as a thermal barrier that prevents direct heat transfer between cells, thereby mitigating the thermal runaway risk associated with high energy density materials while preserving their energy storage capabilities.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The blocking device utilizes materials with specific thermal properties (low thermal conductivity, high heat capacity) to convert the harmful rapid heat propagation into a beneficial delayed thermal response. The insulating layer absorbs and dissipates heat over time, transforming the dangerous thermal runaway scenario into a controlled thermal management situation.

Inventive Principle:

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

2Reliability

If insulating layer is added to prevent heat transfer, then thermal propagation is delayed, but cell structure complexity increases

Engineering Contradiction:

Improvethermal propagation delayVSAvoidcell structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The insulating layer is implemented as a thin film or wrap-around structure that conforms to the cell geometry. This approach provides effective thermal isolation without adding substantial bulk or structural complexity, as the insulating material is applied in a flexible, conformal manner rather than requiring rigid additional components.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The blocking device with insulating layer serves multiple functions simultaneously: it provides thermal isolation between cells, acts as a physical barrier to prevent thermal runaway propagation, and can be integrated into existing cell assembly processes. This multi-functionality reduces the need for separate safety components, thereby limiting the increase in overall structure complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Loss of time

If blocking device with insulating layer is implemented, then thermal propagation time is increased, but manufacturing process complexity increases

Engineering Contradiction:

Improvethermal propagation timeVSAvoidmanufacturing process

Core Design Contradiction:

Loss of timeVSEase of manufacture

Solution Approach 1:

The insulating layer is pre-applied to the cell structure before final assembly, or pre-cut to the required dimensions and shape. This preliminary preparation allows the blocking device to be integrated into the manufacturing process as a straightforward step rather than requiring complex post-assembly operations, thereby maintaining ease of manufacture while achieving the desired thermal propagation delay.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The insulating layer is provided as a flexible material that can be easily wrapped around or applied to the cell surface, similar to applying tape or labeling. This flexibility simplifies the manufacturing process by eliminating the need for complex forming, molding, or fitting operations that would be required for rigid insulating structures.

Inventive Principle:

Principle #30Flexible shells and thin films

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 BLD significantly delays thermal propagation, reducing the risk of fire spread and enhancing safety in battery packs by increasing the time to maximum temperature by over 20 times and maintaining safety without substantial energy density reduction.

Implementation Method 1

absorbing heat through endothermic reactions

Methodology Applied

Scientific EffectEndothermic reaction: Endothermic Reaction

Implementation Method 2

thermally stable insulating layer

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS20250316792A1Cells with blocking devices for delayed heat propagation

Publication Date: 2025.10.09 ENEVATE CORP

AI summary

This disclosure describes a battery device with one or more battery cells and an insulation layer that reduces and/or delays thermal propagation. The insulating layer may be hermetically sealed into the cell. The insulating layer may be thermally stable up to 1800° C. The insulating layer may have a thermal conductivity less than 1 W/(m·K). The insulating layer may comprise a ceramic material. For example, the insulating layer may comprise a porous ceramic paper that is saturated or coated with another material.