Battery Case Metal Barrier Layer Formability Rigidity

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Solution Overview

Problem

Pouch-shaped battery cases face challenges in achieving high formability and rigidity to accommodate large electrode assemblies while maintaining seal integrity, as existing materials like aluminum foil are prone to breaking under mechanical stress.

Innovation Solution

A pouch-shaped battery case structure featuring an outer coating layer, a metal barrier layer with a combination of high formability and high rigidity metals, and an inner sealant layer, where the metal barrier layer includes a first metal (e.g., aluminum) for formability and a second metal (e.g., stainless steel) for rigidity, enhancing both the battery case's capacity and sealability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If aluminum foil is used for the barrier layer to improve formability, then the area and depth of electrode assembly reception unit can be increased, but the sealed portion is easily broken when bent, lowering sealing reliability

Engineering Contradiction:

Improveelectrode assembly reception unit depthVSAvoidsealing reliability

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

The patent applies composite materials by combining aluminum foil (providing formability) with steel foil (providing strength and bend resistance) in a layered barrier structure. This composite construction allows the battery case to achieve both deep electrode assembly reception units and maintained sealing reliability, as the steel layer prevents breakage while the aluminum layer provides formability.

Inventive Principle:

Principle #40Composite materials

2Strength

If the barrier layer thickness is increased to improve strength, then the battery case can withstand mechanical stress better, but the formability and ductility are reduced, limiting capacity increase

Engineering Contradiction:

Improvebattery case strengthVSAvoidelectrode assembly reception unit depth

Core Design Contradiction:

StrengthVSShape

Solution Approach 1:

The patent segments the barrier layer into multiple functional layers with different thicknesses and material compositions. The aluminum foil layer provides formability for deep reception units, while the steel foil layer provides strength. This segmentation allows each layer to optimize its specific function without compromising the other, enabling both deep reception units and high strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

By using composite materials (aluminum-steel foil combination), the patent achieves high strength without increasing overall barrier thickness. The steel layer contributes strength while the aluminum layer maintains formability, allowing the creation of deep electrode assembly reception units with adequate mechanical strength.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If a single metal barrier layer is used to simplify structure, then manufacturing is easier, but both formability and rigidity cannot be simultaneously optimized

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidformability and rigidity balance

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent uses composite materials (aluminum-steel foil layers) to simultaneously achieve high formability from the aluminum layer and high rigidity from the steel layer. This composite approach allows the barrier layer to exhibit both ductility for forming deep reception units and rigidity for maintaining structural integrity, overcoming the limitations of single-metal barriers.

Inventive Principle:

Principle #40Composite materials

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 improves the formability and rigidity of the battery case, allowing for deeper electrode assembly reception units and increased capacity, while preventing seal breakage under mechanical stress, thus enhancing the battery's reliability and performance.

Implementation Method 1

a metal barrier layer having high moisture-blocking efficiency and high thermal conductivity

Methodology Applied

Scientific EffectMoisture blocking: Permeation

Implementation Method 2

a metal barrier layer having high moisture-blocking efficiency and high thermal conductivity

Methodology Applied

Scientific EffectThermal conductivity: Conduction (thermal)

Implementation Method 3

an inner sealant layer located between the metal barrier layer and an inner surface of the battery case

Methodology Applied

Scientific EffectThermal sealing: Heating

Data Source

PatentUS11545707B2Battery case comprising various kinds of metal barrier layers and battery cell including the same

Publication Date: 2023.01.03 LG ENERGY SOLUTION LTD

AI summary

Disclosed herein is a pouch-shaped battery case configured to receive an electrode assembly having a separator interposed between positive and negative electrodes, together with an electrolytic solution, the pouch-shaped battery case including an outer coating layer defining an outer surface of the battery case and configured to protect the electrode assembly from an outside of the battery case, the outer coating layer made of a polymer resin, a metal barrier layer located between the outer coating layer and an inner surface of the battery case, the metal barrier layer having high moisture-blocking efficiency and high thermal conductivity, and an inner sealant layer located between the metal barrier layer and an inner surface of the battery case, the inner sealant layer made of a polymer resin that has high thermal fusibility, the metal barrier layer includes a first metal that has high formability and a second metal that has high rigidity.