Multi-Layer Sheet Material for Lightweight, Leak-Resistant Battery Cases

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Solution Overview

Problem

Existing battery case materials are heavy, offer poor electrical and thermal insulation, and have leakage paths through fixings, compromising safety and efficiency.

Innovation Solution

A multi-layered laminate sheet material comprising composite and metallic layers, adhered with a powder bond technique, provides fixings that do not penetrate the outermost layer, ensuring electrical and thermal insulation, high strength, and leak resistance, while allowing for electromagnetic shielding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional metallic materials (steel or aluminium) are used for battery case, then strength and puncture resistance are sufficient, but weight is heavy and electrical/thermal insulation is poor

Engineering Contradiction:
Improvestrength and puncture resistanceVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The battery case uses a multi-layer composite structure combining aluminium alloy layers with thermoplastic composite layers (such as glass fibre reinforced polypropylene). This composite construction achieves sufficient strength and puncture resistance while significantly reducing weight compared to traditional solid metal cases.

Inventive Principle:
Principle #40Composite materials

2Strength

If traditional metallic materials are used for battery case, then strength is sufficient, but electrical and thermal insulation properties are poor

Engineering Contradiction:
ImprovestrengthVSAvoidelectrical and thermal insulation
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The multi-layer composite structure incorporates non-conductive thermoplastic layers (such as polypropylene or nylon) between metallic aluminium layers. These composite layers provide electrical and thermal insulation while maintaining structural strength, preventing direct electrical contact and thermal transfer between battery components.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The battery case is divided into multiple functional layers: metallic layers for structural strength, thermoplastic layers for insulation and chemical resistance, and intermediate layers for bonding. This segmentation allows each layer to perform its specific function optimally, with insulation layers preventing electrical and thermal conduction.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If fixings extend completely through the sheet material, then components can be secured, but openings form leakage paths allowing external fluids to enter the box or case

Engineering Contradiction:
Improvecomponent securing capabilityVSAvoidleakage resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The case structure is segmented into multiple layers with fixings positioned in intermediate layers rather than penetrating the outermost layer. This segmentation allows the outer layer to remain intact as a fluid barrier while the intermediate layer provides structural support for fixings.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An intermediate layer (such as a thermoplastic or bonding layer) serves as a mediator between the outer fluid-tight layer and the inner structural layer. Fixings are anchored in this intermediate layer, which has sufficient mechanical properties to hold fixings while the outer layer maintains its continuous fluid barrier function.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of operation

If fixings extend through the outermost layer, then components can be attached, but electrical insulation between inner and outer faces is compromised

Engineering Contradiction:
Improvecomponent attachment capabilityVSAvoidelectrical insulation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The case is segmented into multiple functional layers with fixings positioned in intermediate layers. This segmentation ensures that the outermost layer remains intact and electrically insulating, while the intermediate layer provides mechanical support for fixings without compromising the electrical barrier function of the outer layer.

Inventive Principle:
Principle #1Segmentation

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 sheet material offers improved puncture resistance, electrical and thermal insulation, and reduced weight, minimizing fluid leakage and enhancing safety and performance in battery cases.

Implementation Method 1

The layers are adhered to one another using a powder bond based technique in which a power coating is applied to the metallic layers

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

after assembly of the layers, heat and pressure are applied to laminate the layers to one another

Methodology Applied
Scientific EffectThermal softening: Melting

Implementation Method 3

after assembly of the layers, heat and pressure are applied to laminate the layers to one another

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP4171952B1Sheet material
Publication Date: 2025.10.22 STALCOM AUTOMOTIVE TECH LTD
  • EP4171952B1 patent drawingFigure 1~2a
  • EP4171952B1 patent drawingFigure 3~5

AI summary

A sheet material (10) is described comprising a multi-layered laminate of at least three layers and comprising at least one composite material layer (12) and at least one metallic material layer (14), and a fixing (18) cooperating with an intermediate one of the layers and projecting through an outermost one of the layers to a first side of the sheet material (10), the fixing (18) not projecting through an outermost one of the layers to the second, opposite side of the sheet material. The layers may be laminated to one another using a powder bond based technique.