Battery Tab Connection Structure to Prevent Overlapping Weld Regions
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Solution Overview
Problem
The connection region between the tab and the current collecting member in secondary batteries experiences poor current flowing capability due to overlapping connection regions, leading to damage and reduced performance over multiple charge and discharge cycles.
Innovation Solution
A secondary battery design featuring a transition connecting piece with a current collecting portion and a fixing portion, which are connected separately to form non-overlapping first and second connection regions, improving the current flowing capability by preventing multiple connection operations at the same region and reducing structural damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the tab and current collecting member are directly connected forming a single connection region, then the structure is simple, but the current flowing capability deteriorates due to overlapping connection regions and structural damage
Solution Approach 1:
The connection structure is divided into two separate connection regions: a first connection region where the tab connects to the current collecting member, and a second connection region where the supporting portion connects to the current collecting member. This segmentation prevents overlapping connections at the same location, distributing mechanical stress and electrical current across distinct areas, thereby maintaining current flowing capability while avoiding structural damage.
2Strength
If multiple connection operations are performed at the same region, then the connection strength increases, but micro cracks occur reducing performance over cycles
Solution Approach 1:
The connection operations are segmented into two distinct regions: the first connection region for tab connection and the second connection region for supporting portion connection. By separating these operations spatially, each region undergoes only one type of connection operation, preventing the accumulation of micro cracks that would occur with repeated operations at the same location, thus maintaining performance stability over charge-discharge cycles.
Solution Approach 2:
Different parts of the current collecting member are assigned different functions: the first connection region is optimized for electrical connection with the tab, while the second connection region is optimized for structural support. This local differentiation ensures that each region is designed for its specific purpose, preventing the structural damage that would result from concentrating multiple connection functions in a single region.
Data Source
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AI summary
The present application relates to a secondary battery and manufacturing method thereof, a battery module and an apparatus. The secondary battery includes an electrode assembly including a main body portion and a tab extending out from the main body portion; a current collecting member including a guiding section, the guiding section extending in a direction perpendicular to a length direction of the electrode assembly; a transition connecting piece, the transition connecting piece and the current collecting member being separately provided, the transition connecting piece including a current collecting portion and a fixing portion, the current collecting portion being adapted to connect with the tab to form a first connection region, the fixing portion being adapted to connect with the guiding section to form a second connection region, and respective projections of the first connection region and the second connection region on a plane perpendicular to the length direction do not overlap. The secondary battery of the present applicant can reduce the possibility of decrease of the current flowing capability of the tab.