Cylindrical Battery Cell Tab Connection Using a Bent Conductive Member
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Batteries face challenges in maintaining reliability due to stress on the tab during bending, which can lead to detachment of the active material and potential short circuits, affecting energy density and cycle life.
Innovation Solution
A conductive member is connected to the tab, replacing the bending of the tab with bending of the conductive member, reducing stress on the active material layer and enhancing the connection strength through a reinforcement layer and optimized spacing to improve reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tab is bent to connect to the electrode lead-out member, then the electrical connection is established, but stress is transmitted to the active material layer causing detachment risk
Solution Approach 1:
The patent introduces a conductive member as an intermediary component between the tab and the electrode lead-out member. This conductive member absorbs the bending stress through its bent portion, preventing stress transmission to the active material layer while maintaining electrical connection. The conductive member acts as a stress buffer that decouples the mechanical deformation from the fragile tab-active material interface.
Solution Approach 2:
The patent divides the connection structure into separate functional segments: the tab (for electrical connection), the conductive member with conductive body and bent portion (for stress absorption and mechanical connection), and the electrode lead-out member (for external connection). This segmentation allows each component to perform its specific function without compromising the others, particularly protecting the tab from mechanical stress.
2Strength
If the tab is made stronger to prevent detachment, then attachment strength improves, but the flexibility for bending and connection becomes reduced
Solution Approach 1:
The conductive member serves as a mediator that takes on the bending flexibility requirement, allowing the tab to maintain its structural strength for secure active material attachment. The bent portion of the conductive member provides the necessary flexibility and adaptability for connection, while the tab remains strong and rigid for its primary function of holding the active material.
3Productivity
If the conductive member is placed close to the tab connection point, then the current-carrying path is shortened, but the stress concentration at the connection point increases
Solution Approach 1:
The patent distributes the connection point along the length of the tab in the first direction, rather than concentrating it at a single location. The conductive member connects to the tab at a position that is spaced apart from both ends, effectively using the longitudinal dimension of the tab to distribute stress while maintaining an efficient current-carrying path through optimized geometric arrangement.
Data Source
AI summary
Battery cell includes housing including electrode lead-out member, electrode assembly accommodated in the housing and being cylindrical wound structure, and conductive member. The electrode assembly includes first electrode plate including current collector including coated region coated with active material layer and tab not coated with the active material layer. The coated region and the tab are arranged along first direction. The conductive member includes conductive body and bent portion. At least portion of the conductive body is connected to the tab to form first connection region. The bent portion is configured to be electrically connected to the electrode lead-out member, extends from end of the conductive body away from the active material layer, and is continuously bent multiple times. In the first direction, the bent portion entirely extends beyond end of the tab away from the coated region.