Pouch Battery Case Laminate With Shape-Memory Swelling Suppression

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Solution Overview

Problem

Pouch-type battery cases face increased risk of explosion due to swelling phenomena as they are designed for higher density and larger capacity, leading to high tensile stress.

Innovation Solution

Incorporation of a shape-memory resin film between the gas barrier and sealant layers in the pouch-type battery case laminate structure, which shrinks significantly at high temperatures to suppress swelling and prevent explosions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the pouch size is increased to achieve higher density and larger capacity, then the battery capacity is improved, but the tensile stress caused by swelling phenomenon increases and the risk of explosion increases

Engineering Contradiction:
Improvebattery capacityVSAvoidexplosion risk
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The shape-memory resin film is pre-installed in the pouch film laminate structure before battery operation. When swelling occurs, the film automatically activates its shrinkage function to counteract the expansion, preventing explosion before it can occur. This preliminary preparation of the safety mechanism resolves the contradiction by having the protective function ready in advance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The shape-memory resin film changes its physical parameters (dimensional stability, shrinkage ratio) in response to temperature changes. At normal temperatures, the film maintains its original size, but when exposed to high temperatures indicating swelling, it shrinks by a predetermined ratio to counteract the swelling force, thus managing the harmful effect dynamically.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a shape-memory resin film is added to suppress swelling, then safety is improved, but the device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoidfilm laminate structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pouch film is constructed as a composite laminate structure integrating multiple functional layers including the shape-memory resin film. This composite approach combines the protective function of the shape-memory material with the structural requirements of the pouch, achieving enhanced safety without requiring separate independent safety systems.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The shape-memory resin film serves multiple functions simultaneously: it acts as a structural component of the pouch film, provides swelling suppression through its shrinkage mechanism, and functions as a thermal response element. This multi-functionality reduces the need for additional separate safety components, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 shape-memory resin film effectively suppresses swelling and enhances safety by inducing energy drain during abnormal battery behavior, preventing explosions.

Implementation Method 1

a shape-memory resin film is disposed between the gas barrier layer and the sealant layer

Methodology Applied
Scientific EffectShape memory effect: Shape Memory Polymer

Implementation Method 2

the shrinkable pouch film laminate may be provided in a region excluding the sealing portion

Methodology Applied
Scientific EffectThermal shrinkage: Thermal Contraction

Data Source

PatentEP4700940A1Pouch type battery case and lithium secondary battery comprising same
Publication Date: 2026.02.25 LG ENERGY SOLUTION LTD
  • EP4700940A1 patent drawingFigure 1~2
  • EP4700940A1 patent drawingFigure 3
  • EP4700940A1 patent drawingFigure 4

AI summary

A pouch-type battery case according to the present invention includes a shrinkable pouch film laminate in which a base layer, a gas barrier layer, and a sealant layer which are sequentially stacked, and a shape-memory resin film is disposed between the gas barrier layer and the sealant layer.