Intumescent Cell Separator Structure for Battery Thermal Isolation

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Solution Overview

Problem

Existing cell separating elements for battery modules fail to adequately combine elastically compressible properties with effective fire protection and insulation, particularly in the event of thermal runaway, leading to potential thermal bridging and reduced safety.

Innovation Solution

A cell separating element with a flexible outer shell enclosing a fire protection layer made of intumescent material, which inflates upon exposure to high temperatures, is designed to maintain its position within the shell, preventing thermal bridging and enhancing insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the cell separating element uses elastically compressible material to allow battery cell swelling, then the battery cells can swell to a certain extent, but the fire protection and insulation properties are insufficient

Engineering Contradiction:

Improveswelling accommodationVSAvoidfire protection

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The cell separating element combines elastically compressible material with intumescent fire protection material to create a composite structure that simultaneously provides swelling accommodation and fire protection. The intumescent layer is applied as a coating on the compressible material, forming a multi-functional composite that addresses both requirements.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The intumescent fire protection layer is nested on the surface of the elastically compressible material, creating a layered structure where the inner compressible material allows cell swelling while the outer intumescent layer provides fire protection and thermal insulation.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If the cell separating element uses fire protection material to provide insulation, then the insulation properties improve, but the elastically compressible properties are reduced

Engineering Contradiction:

Improvefire protectionVSAvoidswelling accommodation

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a composite material system where the base layer provides elastically compressible properties for swelling accommodation, while the intumescent coating layer provides fire protection. The combination maintains both sets of properties through proper material selection and layer integration.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The intumescent fire protection material is applied as a surface coating rather than replacing the entire compressible material, allowing the bulk material to maintain its compressible properties while the surface layer provides fire protection where it is most needed.

Inventive Principle:

Principle #3Local quality

3Reliability

If the intumescent material is used for fire protection, then the fire protection properties improve, but the material may be destroyed by external heat or lose position when inflating

Engineering Contradiction:

Improvefire protectionVSAvoidposition stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The intumescent material is pre-applied as a coating on the cell separating element before installation, ensuring it is already in position and protected by the compressible material. When heat exposure occurs, the pre-positioned material inflates to provide fire protection without risking displacement.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The intumescent fire protection layer is nested within the cell separating element structure, with the compressible material providing a containment framework that holds the intumescent material in position during both normal operation and thermal events.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 solution provides enhanced elastically compressible properties and robust fire protection, ensuring effective insulation and safety by preventing thermal contact between adjacent battery cells during thermal events.

Implementation Method 1

the at least one fire protection layer is arranged in the interior space and comprises an intumescent material

Methodology Applied

Scientific EffectIntumescent material expansion: Intumescent Materials

Implementation Method 2

the cell separating element is elastically compressible at least in a first direction

Methodology Applied

Scientific EffectElastic compression: Elasticity

Implementation Method 3

a flexible outer shell which encloses an interior space in which a fluid is located

Methodology Applied

Scientific EffectFluid compression: Compression

Data Source

PatentUS20260018708A1Cell separating element with fire protection layer and battery module

Publication Date: 2026.01.15 AUDI AG

AI summary

A cell separating element for arrangement between two battery cells of a cell stack, the cell separating element is elastically compressible at least in a first direction and includes at least one fire protection layer. The cell separating element includes a flexible outer shell enclosing an interior space in which a fluid is located, the at least one fire protection layer is arranged in the interior space and comprises an intumescent material.