Cylindrical Battery Terminal Groove for Weld Spatter Containment
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Solution Overview
Problem
Cylindrical secondary batteries face issues with welding impurities, electrode assembly damage, and welding defects due to misalignment and insufficient welding areas when multiple batteries are connected via busbars.
Innovation Solution
A cylindrical secondary battery design featuring a terminal with a welding groove recessed from its top surface, a coupling part for secure fixation, and gaskets for electrical insulation, along with a case structure that prevents foreign substances and damage from welding heat, ensuring stable welding even with misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding is performed between terminal and current collector plate, then electrical connection is achieved, but welding impurities are generated in the case
Solution Approach 1:
The welding groove extracts the harmful welding impurities from the interior space of the case by providing a dedicated recessed area where welding beads and spatter can fall without contaminating the electrode assembly or electrolyte, thus maintaining electrical connection while preventing contamination
2Reliability
If welding is performed between terminal and current collector plate, then electrical connection is achieved, but electrode assembly is damaged due to welding heat
Solution Approach 1:
The welding groove isolates the high-temperature welding zone from the electrode assembly by providing a recessed space that contains welding heat and prevents it from reaching and damaging the electrode assembly, while still enabling electrical connection between terminal and current collector plate
3Productivity
If multiple secondary batteries are welded through busbar, then battery connection is achieved, but welding defects occur due to misalignment
Solution Approach 1:
The welding groove serves multiple functions: it provides a standardized welding surface for alignment, contains welding impurities, and accommodates welding beads. This multi-functional design enables consistent welding across multiple batteries without requiring high precision alignment, thus improving productivity while maintaining connection quality
4Productivity
If multiple secondary batteries are welded through busbar, then battery connection is achieved, but resistance increases due to insufficient welding area
Solution Approach 1:
The welding groove provides a localized area with optimized geometry for welding, concentrating the welding energy and material in a specific recessed zone. This local quality enhancement ensures sufficient welding area and proper weld bead formation, reducing welding resistance while maintaining efficient battery connection
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
Prevents welding impurities and damage, maintains electrical integrity, and facilitates efficient connection of multiple batteries without increased resistance.
Implementation Method 1
a welding groove recessed downward from a top surface of the terminal outside the main body
Implementation Method 2
a coupling part disposed outside the main body to fix the terminal to the case
Implementation Method 3
a first gasket disposed between the terminal and the case to electrically separate the terminal and the case from each other
Data Source
AI summary
Embodiments relate to a cylindrical secondary battery. A cylindrical secondary battery includes an electrode assembly including a first electrode plate, a separator, and a second electrode plate, a case that accommodates the electrode assembly and of which a lower end is opened to be electrically connected to the second electrode plate, a first current collector plate disposed between a top surface of the electrode assembly and the case and electrically connected to the first electrode plate, a terminal which passes through a top surface part of the case and of which a lower end is electrically and mechanically coupled to a top surface of the first current collector plate, and a cap plate configured to seal a lower end of the case. The terminal includes a main body having a flat top surface and a welding groove recessed downward from a top surface of the terminal outside the main body.