Battery Can Seam Welding With Integrated Cap and Collector Plate
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Solution Overview
Problem
The manufacturing process of cylindrical battery cells faces inefficiencies due to the need for separate welding of the current collector plate to the cap and sidewall member, which reduces energy density, increases production costs, and complicates assembly, while also risking damage to the separator during welding.
Innovation Solution
A welding structure that integrates the current collector plate, cap, and can, allowing for a single welding process that includes a preliminary tack welding step to secure the cap and a continuous seam welding step to seal the can, reducing internal resistance and heat exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate welding processes are used for current collector plate to cap and cap to sidewall member, then electrical connection and sealing are achieved, but production efficiency decreases and production cost increases
Solution Approach 1:
The patent combines the welding of the current collector plate to the cap and the cap to the sidewall member into a single integrated welding process. The cap is positioned to simultaneously contact both the current collector plate and the sidewall member, allowing one welding operation to achieve both electrical connection and sealing functions, thereby improving production efficiency and reducing assembly complexity
Solution Approach 2:
The cap serves multiple functions: it provides electrical connection through contact with the current collector plate, provides sealing through contact with the sidewall member, and acts as a structural closure. By designing the cap to fulfill multiple roles, the patent eliminates the need for separate components and processes for each function, reducing overall assembly complexity
2Manufacturing precision
If mask or jig is used to maintain current collector plate close contact with cap or sidewall member, then welding quality is improved, but internal volume of can is reduced
Solution Approach 1:
The cap is designed with specific geometric features that enable it to self-align and maintain proper contact with both the current collector plate and the sidewall member during welding. The cap's structure includes contact surfaces and positioning features that automatically ensure correct positioning without requiring external masks or jigs, thereby maintaining welding quality while preserving internal volume
Solution Approach 2:
Instead of using external tools (masks or jigs) to position the current collector plate, the patent inverts the approach by using the cap itself as the positioning element. The cap's geometry is designed to guide and maintain the correct position of the current collector plate during assembly and welding, eliminating the need for separate positioning devices
3Productivity
If laser beam is used for welding, then welding speed and precision are improved, but heat energy may damage the separator
Solution Approach 1:
The welding process is divided into discrete, localized welding points rather than continuous welding. Multiple separate weld spots are created at strategic locations where the cap contacts the current collector plate and sidewall member. This segmentation allows heat to be concentrated at specific points for efficient welding while preventing excessive heat accumulation that could damage the separator
Solution Approach 2:
The patent applies welding heat selectively only at the contact points between the cap and the other components, rather than applying heat broadly. By limiting the welding action to only the necessary locations, the process achieves adequate welding strength while minimizing the total heat energy exposed to the separator, thus preventing thermal damage
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 enhances energy density, simplifies the assembly process, reduces production costs, and minimizes the risk of separator damage by dispersing heat effectively through the current collector plate, while maintaining the structural integrity of the battery cell.
Implementation Method 1
a laser beam for welding may penetrate directly into the can
Implementation Method 2
During welding, a large amount of heat energy may be generated
Implementation Method 3
minimizes the risk of separator damage by dispersing heat effectively through the current collector plate
Data Source
AI summary
A battery cell includes a can and an electrode assembly accommodated in the can. The can includes a bottom member, a sidewall member connected to the bottom member and extending upwardly therefrom in an axial direction, and a cap covering an open end of the can at an axial end opposite to the bottom member. A current collector plate is electrically connected to an electrode of the electrode assembly proximate the open end. An edge of the cap is welded by forming a plurality of first welding portions spaced apart from one another along a circumferential direction, in each of which the sidewall member, the edge of the cap, and the current connector plate are all welded together. A second welding portion is also formed continuously along the circumferential direction, in which the sidewall member and the edge of the cap are both welded together.