Cylindrical Battery Cell Tab Bending for Reliable Adapter Welding
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Solution Overview
Problem
Poor welding between the tab and adapter in battery cells leads to performance issues, affecting the overall efficiency and reliability of the battery.
Innovation Solution
A battery cell design where the tab group is bent to form welding and connection sections, which are then stacked and welded to an adapter, with specific geometric constraints and pre-welding structures to ensure a tight and stable connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tab is directly welded to the adapter without bending, then the manufacturing process is simple, but the welding quality is poor and unreliable
Solution Approach 1:
The tab is divided into multiple sections: a connection section connected to the electrode assembly, a bending section for forming the U-shape, and a welding section for joining to the adapter. This segmentation allows each part to perform its specific function optimally, with the bending section enabling the tab to wrap around and form a tight U-shaped configuration that ensures reliable welding contact
Solution Approach 2:
The tab is pre-formed with a U-shaped configuration through bending before the welding process. This preliminary bending action creates the desired geometric shape that enables tight stacking and reliable welding contact with the adapter, preventing poor welding issues before they occur
2Reliability
If multiple tabs are stacked to form a welding portion, then the welding area is increased and welding quality is improved, but the alignment precision required is higher
Solution Approach 1:
The tab is formed into a U-shape with curved bending sections that allow the welding sections to stack in an axial direction. This curved configuration enables natural alignment and tight stacking of multiple tabs, reducing the alignment precision requirements compared to straight tab configurations while still achieving good welding contact
3Adaptability or versatility
If the connection section is made longer to improve flexibility, then the tab can be bent more easily, but the mechanical strength is reduced
Solution Approach 1:
Different sections of the tab have different properties optimized for their specific functions: the connection section has appropriate length and flexibility for bending, the bending section is designed with specific geometry to facilitate U-shape formation, and the welding section has optimized dimensions for strong welding contact. This local quality differentiation ensures both bending flexibility and mechanical strength are maintained where needed
Data Source
AI summary
The battery cell includes an electrode assembly includes a body portion and a tab group, the body portion is a cylindrical structure formed by winding an electrode plate, tabs are led out of at least two turns of the electrode plate from an end face of the body portion, and a plurality of tabs lead out of the electrode plate that are arranged in a radial direction of the body portion form the tab group; and the tab group is bent toward an end of the body portion, the tabs in the tab group are bent to form welding sections and connection sections, and the connection sections are connected between the body portion and the welding sections, and are curved; wherein the welding sections of the plurality of tabs in the tab group are stacked in an axial direction of the body portion and form a welding portion.