Battery Cell Tab Compaction Layout for Crack-Resistant Welding
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Solution Overview
Problem
Existing battery cells experience cracks at the edges of the connecting portions between tab sheets and terminal posts, leading to reduced conductive yield rate and connection strength, which affects the reliability of the battery.
Innovation Solution
The tab sheets are configured with a higher compaction degree in the first area and a lower compaction degree in the second area, with the edge of the connecting portion located in the first area, allowing for reduced pulling stress and improved deformation during welding, thus enhancing the connection strength and reducing cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tab sheets are uniformly compacted, then the connection strength is improved, but cracks appear at the edge of the connecting portion
Solution Approach 1:
The patent applies different compaction degrees to different areas of the tab sheets. The first area (edge region) has a first compaction degree while the second area (center region) has a second compaction degree that is lower than the first. This local differentiation allows the edge regions to have sufficient strength for connection while the center regions maintain flexibility to accommodate welding deformation, thereby preventing cracks at the connecting portion edges.
2Productivity
If the tab sheets are highly compacted, then the conductive yield rate is improved, but pulling stress increases during welding
Solution Approach 1:
The patent creates a spatial variation in compaction degree across the tab sheets. The first area near the edges has higher compaction for good conductivity and connection, while the second area in the center has lower compaction that allows for deformation during welding. This local quality differentiation reduces the overall pulling stress during welding while maintaining adequate conductive yield rate through the compacted edge regions.
3Strength
If the compaction degree is increased, then the connection strength is improved, but the deformation capability during welding is reduced
Solution Approach 1:
The patent implements a dual-compaction-degree structure where the first area (edges) has high compaction for strong connections and the second area (center) has low compaction for deformation capability. This local differentiation allows the tab sheets to simultaneously achieve both strong connections at the edges and sufficient deformation capability in the center during welding processes.
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 improves the conductive yield rate and connection strength between the tab portion and the terminal post, enhancing the reliability of the battery cell by minimizing cracks at the connecting edges.
Implementation Method 1
an edge of the connecting portion on the gathered portion is located in the first area
Implementation Method 2
A compaction degree of the multiple tab sheets in the first area is greater than that in the second area
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Disclosed are a battery cell (102), a battery (100), a power consuming apparatus, an ultrasonic welding head (400), and an ultrasonic welding apparatus (2000), belonging to the technical field of batteries. The battery cell (102) includes a case (1), a terminal post (2), and an electrode assembly (7). The terminal post (2) is provided with ten cases (1). The electrode assembly (7) includes an active material coating portion (71) provided in the ten cases (1), and a tab portion (72) electrically connected to the active material coating portion (71) and the terminal posts (2). The tab portion (72) includes multiple tab sheets (721). The multiple tab sheets (721) are stacked and connected to form a gathered portion (722). The gathered portion (722) has a first area (7221) and a second area (7222). A compaction degree of the multiple tab sheets (721) in the first area (7221) is greater than that in the second area (7222). A connecting portion (8) is formed at a position of the gathered portion (722) used for being electrically connected to the terminal post (2). At least part of an edge (81) of the connecting portion (8) on the gathered portion (722) is located in the first area (7221).