Vacuum Adiabatic Body Laser Welding for Thin-Sheet Sealing
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Solution Overview
Problem
The challenge in creating a vacuum adiabatic refrigerator is the difficulty in achieving perfect welding between conductive resistance sheets and plate members, leading to sealing failures due to thickness differences and welding difficulties, which affects the internal volume and efficiency of the refrigerator.
Innovation Solution
The implementation of a laser welding process with specific control conditions, including a laser beam size of 200 to 375 μm, moving speed of 7 to 15 m/min, and power of 200 to 800 W, along with a jig system using a vacuum pump and inert gas to ensure proper adhesion and prevent welding failures, while using a conductive resistance sheet with a thickness of 10 to 200 μm and plate members with a thickness of 500 to 2000 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a foam urethane adiabatic wall with thickness of 30 cm or more is provided, then thermal insulation performance is improved, but the internal volume of the refrigerator is reduced
Solution Approach 1:
The patent applies vacuum phase transition concept by creating a vacuum space between inner and outer wall panels, eliminating the need for thick solid insulation material. The vacuum state (phase transition from solid/gas to vacuum) provides superior thermal insulation while maintaining compact dimensions, thus resolving the contradiction between insulation performance and internal volume.
Solution Approach 2:
The patent uses thin vacuum adiabatic body panels (first and second wall panels) with thickness much less than conventional foam insulation. These thin panels enclose a vacuum space, providing high insulation performance with minimal space occupation, thereby increasing internal volume while maintaining thermal efficiency.
2Loss of energy
If a conductive resistance sheet with thin thickness is used to resist heat conduction, then the vacuum space can be maintained, but welding between the sheet and plate member becomes considerably difficult
Solution Approach 1:
The patent optimizes the thickness parameter of the conductive resistance sheet to a specific range (0.05-0.5 mm) that balances thermal resistance performance with weldability. This parameter adjustment allows the thin sheet to provide sufficient heat conduction resistance while enabling successful welding to the plate member, resolving the manufacturing difficulty.
Solution Approach 2:
The conductive resistance sheet acts as an intermediary element between the inner and outer wall panels. It is welded to the plate member to seal the vacuum space while simultaneously providing thermal resistance. The sheet's intermediate thickness and material properties enable it to fulfill both sealing and insulation functions, bridging the gap between structural integrity and thermal performance.
3Reliability
If the conductive resistance sheet is welded to the plate member to provide sealing, then vacuum state can be maintained, but sealing failure occurs at specific points due to thickness difference
Solution Approach 1:
The patent specifies precise thickness parameters for the conductive resistance sheet (0.05-0.5 mm) and controls the welding parameters to ensure uniform welding quality across all welding points. This parameter control prevents localized sealing failures by ensuring consistent heat distribution and melting depth during welding, thereby improving overall sealing reliability.
Solution Approach 2:
The patent employs welding parameters that provide slightly excessive heat input to ensure complete penetration and bonding at the interface between the thin conductive resistance sheet and the thicker plate member. This excessive action compensates for the thickness difference and ensures that all welding points achieve adequate sealing, preventing localized failures.
4Ease of manufacture
If the thickness of the conductive resistance sheet is increased to improve welding performance, then welding becomes easier, but heat conduction resistance decreases
Solution Approach 1:
The patent identifies and implements the optimal thickness range (0.05-0.5 mm) for the conductive resistance sheet that simultaneously satisfies both welding performance and heat conduction resistance requirements. Within this range, the sheet is thick enough to be weldable to the plate member but thin enough to provide sufficient thermal resistance, thus resolving the contradiction between manufacturability and energy efficiency.
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 approach ensures stable and reliable sealing of the vacuum adiabatic body, preventing leakage and maintaining the vacuum state, thereby improving the fabrication yield and operational reliability of the refrigerator.
Implementation Method 1
a welding part in which at least one of the conductive resistance sheet and each of the first and second plate members are welded to each other
Implementation Method 2
the plate member is not melted even though the thin conductive resistance sheet is melted
Implementation Method 3
providing a vacuum space part that has a temperature between a temperature of the internal space and a temperature of the external space and is in a vacuum state
Implementation Method 4
the conductive resistance sheet capable of resisting heat conduction between the first plate member and the second plate member
Data Source
AI summary
A refrigerator includes a vacuum adiabatic body including a conductive resistance sheet providing a vacuum space that has a temperature between a temperature of an internal space and a temperature of an external space and is in a vacuum state, the conductive resistance sheet capable of resisting heat conduction between a first plate and a second plate, wherein at least one of the conductive resistance sheet and each of the first and second plates are welded to each other to create a welding part, wherein a plurality of regular beads are provided to a surface of the welding part, and wherein the plurality of regular beads includes: a parabolic inflection region provided at a center portion; linear regions respectively provided at both outsides of the inflection region; and edge regions respectively provided at outsides of the linear regions.