Composite Buffer Pad Structure for Battery Cell Swelling Protection

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Solution Overview

Problem

Conventional buffer pads fail to effectively prevent damage to battery cells due to swelling, leading to potential deformation and damage at the edge of the outermost battery cell in a battery module.

Innovation Solution

A buffer pad with distinct first and second regions having different physical properties is used, where the first region, made of high-rigidity material, prevents movement of the battery cell edge, while the second region, made of low-rigidity material, absorbs vibration and pressure, thereby preventing damage and accommodating swelling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a foam-type buffer pad is used to accommodate volume expansion of the battery cell, then the buffer pad can relieve swelling pressure, but the buffer pad may be broken at large load and fail to prevent damage to the battery cell

Engineering Contradiction:
Improvebuffer pad reliabilityVSAvoidbuffer pad strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The buffer pad is constructed as a composite structure combining a foam layer and a soft layer. The foam layer provides bulk compression capability for volume expansion, while the soft layer positioned at the outermost side protects the battery cell edge from damage. This composite material approach resolves the contradiction by integrating materials with complementary properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different regions of the buffer pad have different physical properties tailored to local requirements. The soft layer is specifically positioned where it contacts the battery cell to provide gentle protection, while the foam layer in other regions handles the main compression load. This local differentiation allows the buffer pad to simultaneously protect the cell and accommodate swelling.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the buffer pad is positioned at the outermost side of the battery cell laminate, then it can accommodate swelling, but the edge part of the battery cell may be damaged due to buffer pad breakdown

Engineering Contradiction:
Improveswelling accommodationVSAvoidbattery cell edge damage
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The buffer pad features a soft layer specifically positioned at the outermost side that contacts the battery cell, while the foam layer is positioned in the interior region. This local differentiation ensures that the cell-contacting region provides gentle protection, while the interior region handles bulk compression, preventing edge damage while maintaining swelling accommodation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The composite structure of foam layer and soft layer allows the buffer pad to simultaneously provide gentle cell protection and effective swelling accommodation. The soft layer prevents edge damage while the foam layer accommodates volume expansion, resolving the contradiction between adaptability and harmful factors.

Inventive Principle:
Principle #40Composite materials

3Device complexity

If a single-rigidity buffer pad is used, then the structure is simple, but it cannot simultaneously prevent edge movement and absorb vibration and pressure

Engineering Contradiction:
Improvebuffer pad structureVSAvoidbattery cell protection
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The buffer pad combines a foam layer and a soft layer with different rigidity properties. The foam layer provides structural support and vibration absorption, while the soft layer prevents edge movement and protects the battery cell. This composite approach enables multi-functionality without significantly increasing structural complexity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The buffer pad is segmented into distinct functional layers: a foam layer for vibration absorption and pressure relief, and a soft layer for edge constraint and cell protection. This segmentation allows each layer to perform its specific function optimally, improving overall protection reliability while maintaining relatively simple structure.

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 buffer pad effectively prevents damage to the outermost battery cell by suppressing edge movement and absorbing pressure, reducing plastic deformation and maintaining the integrity of the battery cell during swelling.

Implementation Method 1

the first region, made of high-rigidity material, prevents movement of the battery cell edge

Methodology Applied
Scientific EffectRigidity:

Implementation Method 2

the second region, made of low-rigidity material, absorbs vibration and pressure

Methodology Applied
Scientific EffectVibration absorption: Damping

Implementation Method 3

the second region, made of low-rigidity material, absorbs vibration and pressure

Methodology Applied
Scientific EffectPressure absorption: Compression

Implementation Method 4

a foam-type buffer pad capable of buffing the volume expansion of the battery cell due to expansion of the electrode and generation of gas

Methodology Applied
Scientific EffectSwelling: Thermal Expansion

Data Source

PatentEP4084199B1Battery module comprising buffer pad for preventing damage to battery cell, and battery pack comprising same
Publication Date: 2026.03.25 LG ENERGY SOLUTION LTD
  • EP4084199B1 patent drawingFigure 1
  • EP4084199B1 patent drawingFigure 2
  • EP4084199B1 patent drawingFigure 3

AI summary

A battery module includes a buffer pad for preventing a damage to a battery cell, and a battery pack including the battery module. It is possible to prevent a damage to the outermost battery cell at the time of the swelling of battery cells by including a buffer pad, where first and second regions having different physical properties are positioned, in a region contacting the outermost battery cell of the battery cell laminate.