Secondary Battery Tab Group Overlap Configuration
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Solution Overview
Problem
The existing power storage devices face issues with tab groups alignment, leading to potential short circuits and inefficient use of space due to non-aligned tab ends, which results in unnecessary space and obstructions, and complicates the welding process.
Innovation Solution
The power storage device is configured with first and second electrode assemblies where tab groups are arranged such that their step portions overlap, reducing contact with the case and allowing for efficient welding by aligning the extensions and welding portions, thereby minimizing space usage and improving welding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the foil collection of the tab group is collected at any position in the stacking direction of the electrodes, then the tabs can be stacked in a compact arrangement, but the distal ends of the tabs are not aligned, creating step portions that may contact the case or produce unused space
Solution Approach 1:
The patent introduces a new spatial dimension by extending tabs in the stacking direction to create an extension portion. This allows the tab group to occupy space in multiple dimensions, with the extension portion filling the gap between the step portion and the case, thereby preventing contact while maintaining compact arrangement.
Solution Approach 2:
The extension portion is nested within the space between the step portion and the case, effectively utilizing the unused space. The insulating structure is also nested around the extension portion, creating a compact integrated assembly that prevents short circuits without increasing overall volume.
2Volume of moving object
If the step portions are directed toward each other to reduce space, then space efficiency improves, but the extensions must extend longer in the stacking direction, producing unused space
Solution Approach 1:
Instead of extending extensions in the stacking direction, the patent creates extension portions that protrude from the side surfaces of tabs in a direction intersecting the stacking direction. This dimensional change allows step portions to face each other for space efficiency while eliminating unused space through the side-protruding extension portions.
3Device complexity
If all tabs are welded at the same time, then the welding process is simplified, but the energy needed for welding increases significantly
Solution Approach 1:
The patent segments the tab group into multiple weldable units by creating distinct extension portions for different tab subsets. This allows the welding process to be divided into multiple stages, welding smaller groups of tabs sequentially rather than all tabs simultaneously, thereby reducing energy consumption while maintaining process simplicity.
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 configuration reduces the space required for tab groups, prevents short circuits, and enhances welding efficiency by allowing proper alignment and overlap of tab groups, improving the overall performance and reliability of the power storage device.
Implementation Method 1
the extension includes a welding portion welded to the conductive member having the same polarity in a state in which all of the tabs configuring the tab group are stacked
Data Source
AI summary
A secondary battery is provided with first and second electrode assembly bodies and first and second negative electrode tab groups. The first and second negative electrode tab groups respectively have collected foil portions each constituted by a plurality of collected tab portions and extension portions. The extension portions of the respective tab groups have portions-to-be-welded and step portions. In the step portions, the plurality of tabs are laminated in a state that the end portions thereof are shifted in a step-like manner. The secondary battery is provided with an overlapped portion where the step portions of the first negative electrode tab group and the second negative electrode tab group are overlapped with each other in the lamination direction of the negative electrode tabs.