Electricity Storage Package Material for Deeper Recess Forming

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Solution Overview

Problem

The packaging materials for power storage devices, as described in existing technologies, have limitations in deep drawing properties, which hinder the achievement of higher energy density and efficient manufacturing processes.

Innovation Solution

A power storage device packaging material is developed with a laminated structure comprising a substrate layer, an adhesion-enhancing treatment layer, a two-part curing type polyurethane adhesive layer, a metal foil layer with anticorrosion treatment layers, a sealant adhesive layer, and a sealant layer. This configuration enhances the deep drawing properties by optimizing the yield stress and breaking elongation of the adhesive layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional packaging materials are used for lithium ion batteries, then the structure is simple and manufacturing is easy, but the deep drawing properties are insufficient and energy density cannot be improved

Engineering Contradiction:
Improvedeep drawing propertiesVSAvoidpackaging material structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies composite materials by creating a multilayer packaging structure consisting of a substrate layer, adhesive layer, metal foil layer, and sealant layer. Each layer serves specific functions: the substrate provides mechanical strength, the adhesive ensures bonding, the metal foil enhances barrier properties and deep drawing performance, and the sealant provides sealing capability. This composite structure resolves the contradiction by achieving superior deep drawing properties while maintaining manufacturability through standardized lamination processes.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The packaging material is segmented into multiple functional layers, each optimized for specific purposes. The substrate layer, adhesive layer, metal foil layer, and sealant layer are separately manufactured and then laminated together. This segmentation allows each layer to be independently optimized for its function, particularly enabling the metal foil layer to provide enhanced deep drawing properties while other layers maintain their respective functions.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If the depth of the recess is increased to store more battery contents, then energy density is improved, but the packaging material may break during deep drawing

Engineering Contradiction:
Improvebattery contents storageVSAvoidpackaging material integrity
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The multilayer composite structure distributes mechanical stresses during deep drawing across multiple layers with different mechanical properties. The metal foil layer provides high strength and ductility to prevent breakage during deep drawing, while the substrate and sealant layers maintain structural integrity. This allows the recess depth to be increased for higher energy density without compromising packaging material strength.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the yield stress of the adhesive layer to a specific range (3500-6500 N/cm²) to balance flexibility and strength. This parameter optimization allows the packaging material to undergo large deformations during deep drawing to form deep recesses while maintaining sufficient strength to prevent breakage, thereby enabling increased battery contents storage.

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If multilayer films are used instead of metal cans, then weight is reduced and production cost is lowered, but deep drawing properties need improvement

Engineering Contradiction:
Improvepackaging material weightVSAvoiddeep drawing properties
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The patent creates a lightweight multilayer film composite that combines the advantages of different materials. The substrate layer uses lightweight polymer materials, the adhesive layer provides bonding with minimal thickness, the metal foil layer is used in optimized amounts to provide necessary mechanical properties, and the sealant layer completes the structure. This composite approach achieves weight reduction compared to conventional metal cans while attaining superior deep drawing properties through the synergistic combination of layers.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifically optimizes the yield stress parameter of the adhesive layer to enhance deep drawing properties. By controlling the adhesive layer's yield stress within a specific range, the multilayer film achieves improved deformability and deep drawing performance, resolving the contradiction between using lightweight multilayer films and maintaining adequate deep drawing properties.

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 improved deep drawing properties of the packaging material allow for the formation of deeper recesses without breakage, thereby increasing the energy density of power storage devices and facilitating more efficient manufacturing processes.

Implementation Method 1

an adhesive layer, which has a yield stress in the range of 3500 to 6500 N/cm2

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

anticorrosion treatment layers respectively provided on both surfaces of the metal foil layer

Methodology Applied
Scientific EffectCorrosion protection:

Implementation Method 3

a sealant adhesive layer, and a sealant layer, which are laminated in this order

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 4

a structure including at least a substrate layer, an adhesive layer, a metal foil layer, a sealant adhesive layer, and a sealant layer, which are laminated in this order

Methodology Applied
Scientific EffectLamination: Lamination

Data Source

PatentEP3654400B1Outer package material for electricity storage devices, and electricity storage device using same
Publication Date: 2025.02.12 TOPPAN HOLDINGS INC
  • EP3654400B1 patent drawingFigure 1
  • EP3654400B1 patent drawingFigure 2
  • EP3654400B1 patent drawingFigure 3(a)~3(b)

AI summary

A power storage device packaging material according to the first aspect of the present disclosure includes a structure including at least a substrate layer, an adhesive layer, a metal foil layer, a sealant adhesive layer, and a sealant layer, which are laminated in this order, wherein the adhesive layer has a yield stress in the range of 3500 to 6500 N/cm2 and breaking elongation of 45 to 200% in a stress-strain curve determined by a tensile test at a tension rate of 6 mm/min. A power storage device packaging material according to the second aspect of the present disclosure includes a structure including at least a substrate layer, an adhesive layer, a metal foil layer, an anticorrosion treatment layer, a sealant adhesive layer, and a sealant layer, which are laminated in this order, wherein the adhesive layer has a glass transition temperature in a range of 140°C or more and 160°C or less.