Two-Fold Current Collector for Controlled Battery Tab Folding
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Solution Overview
Problem
Existing current collectors for prismatic battery cells face challenges during the manufacturing process, including difficulty in controlling the movement of the tab connection portion during folding, which can result in undesirable stress on electrode tabs and irregular folds. Additionally, the design is suboptimal in terms of compactness and energy density due to the need for sufficient spacing between the electrode tabs and the current collector.
Innovation Solution
The current collector design incorporates two fold portions at both axial ends of the tab connection portion, allowing for symmetrical force application during folding. This design enables a symmetrical folding operation, minimizing stress on the electrode tabs and improving the compactness and energy density of the battery cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single fold portion is used to link the tab connection wing to the terminal foot connection wing, then the current collector can be folded after welding operations, but the movement of the tab connection portion is difficult to control during folding, resulting in undesirable stress on electrode tabs and irregular folds
Solution Approach 1:
The single fold portion is divided into two separate fold portions (first fold portion and second fold portion) that are positioned at different locations. This segmentation allows the folding force to be applied more symmetrically and controllably, with each fold portion contributing to the overall folding motion. The tab connection portion can move in a more controlled manner during folding, reducing stress concentration and improving fold regularity.
2Ease of manufacture
If the tab connection wing is positioned at a right angle relative to the terminal foot connection wing to provide space for welding heads, then welding operations can be performed, but sufficient spacing is required between the electrode tabs and the tab connection portion, resulting in suboptimal compactness and energy density
Solution Approach 1:
The current collector is designed with dynamic folding capability, transitioning from an unfolded configuration (providing welding access) to a folded configuration (reducing spacing requirements). The two fold portions enable this dynamic transformation, allowing the tab connection wing to move closer to the terminal foot connection wing after welding, thereby improving compactness and energy density while maintaining manufacturing feasibility.
Data Source
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AI summary
A current collector (10) for connecting a set of electrode tabs (14) to a terminal foot (52) of a battery cell subassembly (54), comprises a sheet metal piece with a tab connection wing (12), a terminal foot connection wing (14), a first fold portion (16) and a second fold portion (18) linking the tab connection wing (12) to the terminal foot connection wing (14) along a reference axis (100). The tab connection wing (12) comprises a tab connection portion (20), a first end portion (28), which links the tab connection portion (20) to the first fold portion (16) at a first axial end of the tab connection portion (20) and extends axially along the first fold portion (16). and a second end portion (32), which links the tab connection portion (20) to the second fold portion (18) at a second axial end of the tab connection portion (20) and extends axially along the second fold portion (18).