Battery Tab Welding Geometry for Misalignment-Tolerant Joining
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Solution Overview
Problem
The issue of poor welding yield between a multi-layer tab and a connecting sheet in batteries due to misalignment during ultrasonic welding, which affects the service performance of the battery.
Innovation Solution
The battery design includes a specific relationship between the welding width, depth, and thickness of the welding mark on the connecting sheet, ensuring 0.1≤L1×(H1/H2)≤1.75, to improve the bonding strength and yield of the connection between the connecting sheet and the tab, thereby addressing misalignment issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultrasonic welding is used to connect the tab and connecting sheet, then the welding process is efficient and fast, but the welding yield is poor due to tab misalignment
Solution Approach 1:
The patent applies preliminary action by designing a positioning structure on the connecting sheet (including positioning holes or positioning protrusions) that预先 establishes accurate alignment between the tab and connecting sheet before the welding process occurs. This pre-positioning ensures that even during high-speed automated welding, the tab remains correctly aligned with the welding area, thereby maintaining high welding yield without sacrificing productivity
Solution Approach 2:
The patent introduces an intermediary element - the positioning structure (positioning holes or positioning protrusions) - that acts as a mediator between the tab and connecting sheet. This intermediary component facilitates precise alignment and stable positioning during the welding process, resolving the misalignment issue that causes poor welding yield while maintaining the efficiency of ultrasonic welding
2Reliability
If the welding mark dimensions are increased to compensate for misalignment, then the welding yield improves, but the connecting sheet requires greater thickness which increases material usage
Solution Approach 1:
By implementing preliminary positioning through positioning holes or protrusions, the patent ensures accurate alignment before welding occurs. This pre-alignment eliminates the need to increase welding mark dimensions as a compensatory measure, allowing the use of smaller, more precise welding marks that maintain high welding yield without requiring increased connecting sheet thickness
Solution Approach 2:
The patent changes the critical parameter of alignment precision through the positioning structure, rather than changing the welding mark size or connecting sheet thickness. This parameter change enables maintaining optimal welding mark dimensions while achieving high welding yield through improved positional accuracy
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 enhances the welding yield and overall safety performance of the battery by ensuring reliable bonding between the connecting sheet and the tab, reducing incomplete welding caused by misalignment.
Implementation Method 1
The electrical connection between an electrode assembly and a connecting sheet is achieved by ultrasonic welding between a tab provided on the electrode assembly and the connecting sheet
Data Source
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AI summary
A battery and an electrical device are disclosed therein. The battery includes: an electrode assembly, the electrode assembly includes a winding core main body and a tab provided on the winding core main body; one end of the tab is connected with the winding core main body; and a connecting sheet, the connecting sheet is welded with the other end of the tab, a welding mark is formed on the connecting sheet; where the welding mark has a welding width of L1 mm and a depth of H1 mm, the connecting sheet has a thickness of H2 mm, and the battery satisfies: 0.1≤L1×(H1/H2)≤1.75. In the present application, by defining the relationship of the welding width and depth of the welding mark and the thickness of the connecting sheet, the problem of incomplete welding caused by tab misalignment can be avoided, improving the welding yield between the connecting sheet and the tab, and further improving the overall safety performance of the battery.