Cylindrical Battery Current Collector With Acute-Angle Weld Layout
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Solution Overview
Problem
Existing cylindrical battery cells face issues with high internal resistance, weld-related process problems such as separator melting and welding splatter, particularly due to increased circuit resistance at connection points between current collectors and electrode assemblies.
Innovation Solution
A cylindrical battery cell design with a first uncoated area acting as an electrode tab, featuring a current collector with acute-angle welds between the uncoated area and terminal coupling portions, minimizing the number of welds and optimizing their arrangement to reduce internal resistance and prevent separator melting and welding splatter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of welds is increased to improve connection strength between current collector and electrode assembly, then connection reliability is improved, but process issues such as separator melting and welding splatter increase
Solution Approach 1:
The patent changes the geometric parameters of the welds by configuring them at acute angles (specifically 45 degrees or less) rather than conventional orientations. This parameter change allows the welds to be more efficient in connecting the current collector to the electrode assembly, reducing the total number of welds needed while maintaining connection reliability and minimizing harmful effects like separator melting and welding splatter.
Solution Approach 2:
The patent applies local quality by concentrating the welding function at specific acute-angle locations where the current collector connects to the electrode assembly. Instead of distributing multiple welds across various locations, the design focuses welding quality at strategically positioned acute-angle points, achieving reliable connection with fewer welds and reduced process issues.
2Reliability
If electrode tabs are provided on the entire area of both sides of the jelly-roll to increase current collection efficiency, then current collection efficiency is improved, but the number of welds and circuit resistance increase
Solution Approach 1:
The patent extracts the essential function of current collection from the conventional approach of providing electrode tabs across the entire area. Instead, it uses a focused acute-angle weld configuration that captures the necessary current collection function with minimal welding, thereby reducing device complexity and the number of welds while maintaining current collection efficiency.
Solution Approach 2:
The patent changes the geometric parameters of the connection structure by using acute-angle welds at specific locations rather than distributed tabs. This parameter change in the connection geometry achieves effective current collection with fewer welds, reducing circuit resistance and simplifying the overall structure.
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 effectively reduces internal resistance, minimizes weld-related issues, and enhances process efficiency by dispersing impact and vibration, thereby improving the performance and durability of the battery cell.
Implementation Method 1
a first uncoated-area coupling portion extending inward from the edge portion and welded to the first uncoated area, and a terminal coupling portion spaced apart from the first uncoated-area coupling portion and welded to the cell terminal
Data Source
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AI summary
A cylindrical battery cell according to an embodiment of the present disclosure may include an electrode assembly including a first electrode, a second electrode, and a separator interposed therebetween, which are wound around a winding axis to define a core and an outer surface, wherein the first electrode may include a first uncoated area not having an active material layer coated on a longitudinal end along a winding direction and exposed to the outside of the separator, and wherein at least a portion of the first uncoated area may be used as an electrode tab, a battery can including an opening on one side and configured to receive the electrode assembly through the opening, a cell terminal configured to pass through a surface of the battery can located opposite the opening, an edge portion disposed at a top of the electrode assembly, a first uncoated-area coupling portion extending inward from the edge portion and welded to the first uncoated area, and a terminal coupling portion spaced apart from the first uncoated-area coupling portion and welded to the cell terminal, wherein a plurality of welds may be provided between the first uncoated area and the current collector, and wherein an angle between adjacent welds among the plurality of welds may be configured to be an acute angle.