Battery Case Welding Layout for Airtight Closed-Loop Sealing

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Solution Overview

Problem

Existing manufacturing methods for battery cases face challenges in securing airtightness and watertightness due to structural constraints, limiting the arrangement of internal components and requiring additional protective measures when forming closed-loop welding lines on the same surface.

Innovation Solution

A method involving multiple welding operations on different surfaces using distinct welding machines and techniques, such as arc welding and friction stir welding, to form a closed-loop welding line along the circumferential region of the members, allowing for increased structural freedom and improved airtightness and watertightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the support panel and frame are welded on the same surface to form a closed-loop welding line, then the airtightness and watertightness performance are secured, but the structural freedom is limited and additional protective members are required

Engineering Contradiction:
Improveairtightness and watertightness performanceVSAvoidstructural freedom
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from forming a closed-loop welding line on a single surface (2D constraint) to forming welding lines on opposite surfaces of the support panel (utilizing the third dimension). Specifically, a first welding line is formed on a first surface of the support panel, and a second welding line is formed on a second surface (opposite to the first surface), thereby achieving airtightness without constraining the layout on a single plane.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the support panel and frame are welded on the same surface, then the airtightness is secured, but the arrangement of internal components is limited and electrical components must protrude from the outer line

Engineering Contradiction:
ImproveairtightnessVSAvoidarrangement of internal components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes the third dimension by forming welding lines on opposite surfaces of the support panel rather than confining them to a single surface. This dimensional transition allows electrical components and cooling water ports to be arranged within the boundary of the support panel without requiring protrusions, as the welding lines are distributed across two surfaces.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If a separate protective member and fastening structure are added to protect electrical components, then the components are protected, but the device complexity increases

Engineering Contradiction:
Improveprotection of electrical componentsVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The support panel serves multiple functions: it provides structural support, contains the electrical components within its boundary, and forms the welding lines on its surfaces to achieve airtightness. This multi-functionality eliminates the need for separate protective members, as the support panel itself integrates the protective role.

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

4Reliability

If a sealer is applied to supplement the closed-loop shape, then the airtightness is partially improved, but a separate process is added and the airtightness cannot be fully secured

Engineering Contradiction:
ImproveairtightnessVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent performs welding operations on both surfaces of the support panel to pre-establish the complete airtight sealing structure before final assembly. By forming welding lines on opposite surfaces that connect to each other, the airtightness is achieved through the welding structure itself without requiring subsequent sealing operations.

Inventive Principle:
Principle #10Preliminary action

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 method ensures secure airtightness and watertightness while allowing for more flexible structural designs, accommodating internal components without protrusions and enhancing collision stability.

Implementation Method 1

the first welding line may be formed on the first surface using a first welding machine... The first welding operation may be performed by arc welding

Methodology Applied
Scientific EffectArc welding: Electric Arc

Implementation Method 2

the second welding line may be formed on the second surface using a second welding machine... The second welding operation may be performed by friction stir welding (FSW)

Methodology Applied
Scientific EffectFriction stir welding: Friction Welding

Data Source

PatentEP4241911B1Method of manufacturing welded structure, welded structure, and battery case
Publication Date: 2025.07.30 HYUNDAI MOBIS CO LTD
  • EP4241911B1 patent drawingFigure 1
  • EP4241911B1 patent drawingFigure 2
  • EP4241911B1 patent drawingFigure 3

AI summary

A method of manufacturing a welded structure includes a preparation operation of arranging a first member to overlap a second member; a first welding operation of forming a first welding line on a first surface of the first member by welding a portion at which the first member overlaps the second member, the first surface of the first member being a surface of the first member facing the second member; a second welding operation of forming a second welding line on a second surface of the first member by welding the portion at which the first member overlaps the second member, the second surface of the first member being a surface opposite to the first surface; and connecting the first welding line to the second welding line.