Battery Terminal Caulking Structure for Defect-Free Welding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing electrical energy storage devices, such as lithium ion batteries, often experience welding defects due to close contact between the terminal and current collecting part during the welding process, leading to gas entrapment and resulting in internal damage like blowholes or pits, which can cause unstable conductive connections and increased electric resistance.
Innovation Solution
The electrical energy storage device design includes a step part on the side surface of the current collecting part to accommodate the caulking part of the terminal, and a space is provided near the welding bonding area to allow gas escape, preventing welding defects and ensuring a stable, low-resistance connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the terminal is caulked inside the counterbore hole making close contact with the current collecting part, then the caulking strength is improved, but welding defects such as blowholes or pits occur in the welding bonding part
Solution Approach 1:
The counterbore hole is divided into two functional zones: an upper caulking region where the terminal is deformed to achieve strong mechanical bonding, and a lower welding region that maintains a gap from the current collecting part to prevent gas entrapment during welding. This segmentation allows both caulking strength and welding quality to be optimized simultaneously.
Solution Approach 2:
The invention introduces a vertical dimensional distinction within the counterbore hole structure. By creating a stepped configuration where the caulking surface is positioned at a different vertical level than the welding surface, the design enables independent optimization of mechanical bonding and welding processes without interference between the two functions.
2Strength
If the terminal and current collecting part are in close contact, then the caulking strength is improved, but gas generated during welding has no way out and remains in the welding bonding part
Solution Approach 1:
The invention extracts the harmful effect of gas entrapment by designing a gap structure that specifically removes the obstruction to gas escape. The lower portion of the counterbore hole maintains a predetermined distance from the current collecting part, creating an extraction pathway for gas to escape during welding while the upper portion provides caulking strength.
3Strength
If the terminal is caulked to deform contact with bottom surface and side surface of counterbore hole, then caulking strength is improved, but welding defect such as blowhole or pit occurs
Solution Approach 1:
The counterbore hole is segmented into distinct functional regions: the upper region with the bottom surface and side surfaces for caulking deformation, and the lower region with a gap for precise welding control. This segmentation prevents the interference between caulking deformation and welding precision.
Solution Approach 2:
Different regions of the counterbore hole are given different local qualities: the upper portion has contact surfaces optimized for mechanical deformation and bonding strength, while the lower portion maintains a gap optimized for welding precision and gas escape. This local differentiation resolves the contradiction between caulking strength and welding quality.
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 design effectively suppresses welding defects and enhances the reliability of the electrical connection by allowing gas to escape during the welding process, resulting in a stable welding bonding part with improved conduction reliability.
Implementation Method 1
due to swelling of air, volatilization of organic substances, and the like by welding heat, high-temperature gas (fume) may be generated
Implementation Method 2
swelling of air, volatilization of organic substances, and the like by welding heat, high-temperature gas (fume) may be generated
Data Source
AI summary
An electrical energy storage device disclosed herein includes a current collecting part including a penetration hole, a terminal including a shaft part inserted to a terminal extraction hole of a case main body and the penetration hole and a caulking part caulked to a periphery of the penetration hole, a step part that is provided at a side surface of the penetration hole of the current collecting part and has at least a part of the caulking part of the terminal disposed therein, and a welding bonding part between a peripheral part of the penetration hole of the current collecting part and the caulking part of the terminal, in which a space is provided between the current collecting part and the terminal in a vicinity of the welding bonding part.