Battery Module-to-Box Adhesive Joint for Vibration Stability

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Solution Overview

Problem

Existing battery packs face safety risks due to low stiffness and inadequate clamping force, which can lead to vibrations and instability, particularly affecting the connection between batteries and the box assembly.

Innovation Solution

The use of a first adhesive member to fix batteries to the box assembly, optimizing the area and elastic modulus of the adhesive to ensure dynamic performance and connecting strength, with specific ratios of area A and elastic modulus B (0.02cm²/MPa ≤ A/B ≤ 9cm²/MPa) to enhance bonding and prevent detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If batteries are fixed using only end plates and side plates connected via bolts, then the structure is simple and easy to manufacture, but the overall stiffness of the battery module is low and clamping force is insufficient

Engineering Contradiction:
Improveease of manufactureVSAvoidstiffness
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent combines mechanical fastening (bolts connecting end plates and side plates) with chemical bonding (adhesive layer between battery casing and box assembly) to create a hybrid fixation system. This merging of mechanical and chemical fixation methods simultaneously achieves ease of manufacture and high stiffness/clamping force.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a composite fixation approach by combining metal fasteners (bolts, end plates, side plates) with adhesive materials. This composite system leverages the advantages of both mechanical strength and bonding flexibility, resolving the contradiction between manufacturing simplicity and structural stiffness.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If batteries are not directly connected with the box assembly, then the structure allows for easier assembly and disassembly, but the connecting strength between battery module and box assembly is insufficient

Engineering Contradiction:
Improveease of assemblyVSAvoidconnecting strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent introduces an adhesive layer as an intermediary between the battery casing and the box assembly. This adhesive mediator provides strong chemical bonding while maintaining the modular structure, allowing batteries to be indirectly but firmly connected to the box assembly without compromising ease of assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent merges mechanical connection (bolts securing end plates and side plates) with chemical connection (adhesive bonding battery casing to box assembly) to achieve both ease of operation and high connecting strength simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If the battery module uses only mechanical fastening with bolts, then the structure is simple, but the clamping force on middle batteries is insufficient leading to vibration and safety risks

Engineering Contradiction:
Improvedevice complexityVSAvoidsafety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces part of the mechanical fastening system with a chemical bonding system. The adhesive layer provides continuous clamping force to middle batteries without requiring additional mechanical fasteners, thereby maintaining device simplicity while significantly improving safety and reducing vibration risks.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The adhesive acts as an intermediary that distributes clamping force uniformly across all batteries including middle ones, eliminating the vibration and safety issues associated with insufficient mechanical clamping force while keeping the overall device complexity low.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This solution effectively increases the connecting strength between the battery module and the box assembly, reducing safety risks during vibrations and maintaining dynamics performance, while also optimizing adhesive usage and energy density.

Implementation Method 1

the first batteries are fixed to the box assembly via the first adhesive member... the area A of the first surface and the elastic modulus which is defined as Young's modulus B of the first adhesive member are comprehensively considered

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP3736879B1Battery pack and vehicle
Publication Date: 2024.11.20 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED
  • EP3736879B1 patent drawingFigure 1
  • EP3736879B1 patent drawingFigure 2~3
  • EP3736879B1 patent drawingFigure 4~5

AI summary

The present invention provides a battery pack and a vehicle. The battery pack comprises a battery module, a box assembly and a first adhesive member. The battery module comprises first batteries arranged sequentially in a horizontal direction. The first battery comprises an electrode assembly and a case, and the electrode assembly is received in the case. The electrode assembly comprises a first electrode plate, a second electrode plate and a separator. The box assembly has a connection portion, and the connection portion is positioned at a side of the battery module in the vertical direction. An outer surface of the case comprises a first surface, and the first surface is connected with the connection portion via the first adhesive member. An area A of the first surface and an elastic modulus B of the first adhesive member satisfy a relationship: 0.02cm2/MPa≤A/B≤9cm2/MPa.