Battery Pack Cover Structure for Swelling Absorption and Cell Pressure Control

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Solution Overview

Problem

Conventional battery packs face issues with decreased energy density, structural rigidity, and explosive pressure increases due to swelling, necessitating larger empty spaces and buffer pads that exacerbate these problems.

Innovation Solution

A battery pack structure with perpendicular cell stacking, elastic members, and a rigid pack tray design that absorbs swelling while maintaining consistent pressure on cells, using elastic members to individually control swelling and enhance structural rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a buffer pad is inserted between adjacent battery cells to absorb swelling, then swelling control is improved, but the pressure applied to battery cells increases explosively as swelling amount increases

Engineering Contradiction:
Improveswelling controlVSAvoidpressure applied to battery cell
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The patent changes the physical state and mechanical properties of the elastic member material to provide progressive resistance. The elastic member is designed with specific elastic modulus and damping coefficients that allow it to absorb swelling forces through elastic deformation rather than rigid compression, transforming the pressure application mechanism from explosive to controlled.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The elastic member may comprise a composite structure combining materials with different mechanical properties to achieve both swelling absorption and controlled pressure application. The composite material design allows the member to exhibit nonlinear elastic behavior, providing increasing resistance in a controlled manner rather than explosive pressure increase.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a larger empty space is secured to absorb volume expansion due to swelling, then swelling control is improved, but energy density decreases

Engineering Contradiction:
Improveswelling controlVSAvoidenergy density
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The elastic member acts as a flexible structural element that provides swelling absorption functionality without requiring large empty spaces. The thin film or shell structure of the elastic member allows it to be integrated into the compact battery pack design, absorbing volume expansion forces while occupying minimal space that would otherwise be available for active materials.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The elastic member serves as an intermediary mechanism between the swelling battery cells and the rigid pack housing. Rather than requiring large empty spaces for cells to expand into, the elastic member mediates the swelling forces, absorbing expansion in a controlled manner while maintaining compact overall pack dimensions for high energy density.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If the stack direction of battery cells is made parallel to the ground to secure structural rigidity, then structural rigidity is improved, but energy density decreases due to increased empty space requirements

Engineering Contradiction:
Improvestructural rigidityVSAvoidenergy density
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent introduces dynamic swelling control through the elastic member that adapts to cell expansion forces. This dynamic mechanism allows the system to maintain structural integrity during swelling events without requiring the static empty space buffers that would reduce energy density, enabling optimized cell orientation for both rigidity and density.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention extracts the swelling absorption function from the overall pack structure design and consolidates it into dedicated elastic members. This extraction allows the pack housing to be designed with minimal empty space for high energy density, while the extracted swelling control function is performed by the elastic members positioned strategically between cells.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If the number of buffer pads is increased to control swelling, then swelling control is improved, but device complexity increases

Engineering Contradiction:
Improveswelling controlVSAvoidnumber of buffer pads
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The elastic member is designed as a universal component that can be applied to multiple cell interfaces within the pack. Rather than requiring different buffer pad configurations for different cell positions, the same elastic member design can be used throughout the pack, reducing complexity while maintaining effective swelling control across all cell interfaces.

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

Solution Approach 2:

The invention merges the swelling absorption function with the structural support function into a single elastic member component. This consolidation eliminates the need for separate buffer pads and structural elements, reducing the total number of components and simplifying the overall device structure while maintaining both swelling control and structural integrity.

Inventive Principle:
Principle #5Merging (Combining)

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

Prevents energy density loss, maintains structural rigidity, and avoids explosive pressure increases by minimizing empty space and using elastic members to manage swelling effectively.

Implementation Method 1

a first elastic member is positioned between a module cover and the battery module, and a second elastic member is positioned between a tray base and the battery module

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4131605B1Battery pack having structure capable of swelling control and vehicle including the battery pack
Publication Date: 2025.12.31 LG ENERGY SOLUTION LTD
  • EP4131605B1 patent drawingFigure 1
  • EP4131605B1 patent drawingFigure 2
  • EP4131605B1 patent drawingFigure 3

AI summary

A battery pack according to an embodiment of the present disclosure includes: a plurality of battery modules; a pack tray in which the plurality of battery modules are accommodated; a module cover covering an opening portion formed over the pack tray; a pack cover covering the module cover; and an upper elastic member located between the module cover and the pack cover and compressed, when the module cover moves toward the pack cover due to swelling of the battery module, to absorb volume expansion due to the swelling.