Battery Module Housing Weld Joint for Shock-Resistant Sealing

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Solution Overview

Problem

The existing battery module housing structures are prone to damage from external shocks and have reduced sealing properties due to weak welding connections, which can lead to leakage and fatigue damage from repeated loads and vibrations, exacerbated by surface defects like holes, craters, and burrs formed during the welding process.

Innovation Solution

A battery module design featuring a welding joint portion with a bonding region and a surface region, where the surface region has a finer microstructure than the bonding region, created by different thermal histories, and covers the bonding region to prevent surface defects and improve mechanical properties, using a combination of aluminum alloys for the housing members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If welding is used to join housing members to form a sealed internal accommodating space, then the housing achieves structural integrity and sealing properties, but the connection portion becomes vulnerable to external shock and surface defects reduce mechanical properties

Engineering Contradiction:
Improvemechanical properties of welding jointVSAvoidresistance to external shock
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies local quality by creating a surface region with distinct microstructural characteristics (finer grain structure, different phase composition) specifically at the welding joint surface. This localized modification enhances shock resistance and mechanical properties at the critical surface region without altering the overall welding structure, directly addressing the vulnerability of welded portions to external shock and surface defects

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by modifying the thermal history parameters during the welding process to create a surface region with different microstructural parameters (grain size, phase distribution, impurity concentration) compared to the bonding region. This thermal parameter control transforms the surface microstructure to achieve improved mechanical properties and shock resistance while maintaining the sealing function

Inventive Principle:
Principle #35Parameter changes

2Productivity

If conventional welding processes are used to join housing members, then manufacturing efficiency is maintained, but surface defects such as holes, craters, and burrs are formed that reduce mechanical properties

Engineering Contradiction:
Improvewelding manufacturing efficiencyVSAvoidsurface quality of welding joint
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by incorporating surface region formation into the welding process itself through controlled thermal history, rather than requiring separate post-welding surface treatment operations. This preliminary creation of the refined surface microstructure during welding eliminates the need for additional machining or surface treatment steps, maintaining manufacturing efficiency while achieving high surface quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent converts the typically harmful thermal effects of welding (which cause surface defects) into a beneficial process by carefully controlling the thermal history to create a surface region with refined microstructure. The thermal energy that would normally create holes and craters is instead directed to form a finer-grained surface layer with improved mechanical properties, turning the welding process's inherent thermal effects from harmful to beneficial

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 design enhances mechanical properties and reduces the risk of surface defects, improving the aesthetic finish and resistance to impurity-induced defects, thereby increasing the durability and reliability of the battery module.

Implementation Method 1

a bonding region in which the first base material and the second base material are melt-bonded

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

the housing includes a welding joint portion in which a first base material of a first alloy and a second base material of a second alloy are welded

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 3

the bonding region and the surface region have different microstructures due to different thermal histories

Methodology Applied
Scientific EffectSolidification: Crystallisation

Data Source

PatentEP4184677B1Battery module
Publication Date: 2025.01.15 SK ON CO LTD
  • EP4184677B1 patent drawingFigure 1~2
  • EP4184677B1 patent drawingFigure 3A~3B
  • EP4184677B1 patent drawingFigure 4

AI summary

Provided is a battery module including a housing having an internal accommodating space and a plurality of battery cells located in the internal accommodating space, wherein the housing includes a welding joint portion in which a first base material of a first alloy and a second base material of a second alloy are welded, the welding joint portion includes a bonding region in which the first base material and the second base material are melt-bonded and a surface region covering the bonding region, and the bonding region and the surface region have different microstructures.