Composite Battery Module Frame for Swelling Stress and Weight Reduction

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Solution Overview

Problem

Existing module frames for secondary batteries, typically made of metal materials, face limitations in reducing weight, product differentiation, and are challenged by the need to withstand battery cell swelling and increased capacity demands.

Innovation Solution

A module frame formed from a composite material comprising fiber-reinforced plastic (FRP) with a layered cross-sectional structure, including layers of glass or carbon fibers and metal sheets, optimized for stress directions, providing enhanced mechanical strength, insulation, and fire resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal materials are used for module frame, then mechanical strength and impact protection are improved, but weight increases and manufacturing flexibility is limited

Engineering Contradiction:
Improvemechanical strengthVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by combining FRP (fiber-reinforced plastic) with metal sheets in a layered structure. The FRP layers provide high strength-to-weight ratio while the metal sheets add mechanical strength and impact resistance. This composite approach resolves the contradiction by achieving both light weight and high mechanical strength simultaneously, rather than relying solely on heavy metal materials.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The module frame is segmented into multiple functional layers: FRP layers for weight reduction and basic strength, metal sheets for enhanced mechanical strength and impact protection, and insulation layers for thermal management. This segmentation allows each layer to contribute its specific properties, achieving overall high strength while maintaining low weight.

Inventive Principle:
Principle #1Segmentation

2Reliability

If metal materials are used for module frame, then impact protection is improved, but weight reduction and product differentiation become difficult

Engineering Contradiction:
Improveimpact protectionVSAvoidweight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The composite structure combines FRP's lightweight properties with metal sheets' impact resistance. The FRP layers absorb and distribute impact forces across the structure, while the metal sheets provide hard protection against external impacts. This combination achieves reliable impact protection without the full weight penalty of traditional metal-only construction.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Metal sheets are strategically positioned at specific locations within the composite structure where impact protection is most needed, rather than using metal throughout the entire frame. This localized application provides targeted impact protection while minimizing overall weight increase.

Inventive Principle:
Principle #3Local quality

3Weight of moving object

If composite materials including FRP are used, then weight is reduced and manufacturing efficiency is improved, but electrical insulation and fire resistance must be ensured

Engineering Contradiction:
ImproveweightVSAvoidelectrical insulation and fire resistance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent uses FRP's inherent electrical insulation properties to provide safety functionality while maintaining weight reduction benefits. The FRP layers act as electrical insulators between battery cells, eliminating the need for additional insulation layers. For fire resistance, the composite structure incorporates materials with appropriate thermal stability and designs the layered configuration to slow heat transfer.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The FRP material serves multiple functions simultaneously: structural support, weight reduction, electrical insulation, and fire resistance. This multi-functionality resolves the contradiction by integrating safety requirements into the primary structural material rather than adding separate components for each function.

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

4Quantity of substance

If battery cell capacity is increased, then energy density is improved, but swelling stress and structural stability challenges increase

Engineering Contradiction:
Improvebattery cell capacityVSAvoidswelling stress resistance
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The composite structure with FRP and metal sheets provides high strength-to-weight ratio, enabling the frame to withstand the increased swelling stresses generated by higher capacity battery cells. The layered configuration distributes swelling forces across multiple layers, preventing localized stress concentration that could lead to structural failure.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The modular layered structure segments the stress management function across different layers. FRP layers handle tensile stresses from swelling, while metal sheets provide compressive strength and dimensional stability. This segmentation allows the structure to accommodate larger battery cells without compromising structural integrity.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4664633A1Module frame for secondary battery and secondary battery including same
Publication Date: 2025.12.17 LG ENERGY SOLUTION LTD
  • EP4664633A1 patent drawingFigure 1A
  • EP4664633A1 patent drawingFigure 1B
  • EP4664633A1 patent drawingFigure 1C

AI summary

A module frame for a secondary battery according to various embodiments may be configured to accommodate a battery cell stack including multiple battery cells stacked along one direction, wherein the module frame is formed by a composite material-based plate including fiber reinforced plastic; and the plate includes at least multiple layers including a first layer and a second layer and has a layered cross-section symmetrical in the thickness direction of the plate. In addition, other embodiments are possible.