Secondary Battery Electrode Tab Structure for Swelling Relief
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Solution Overview
Problem
Secondary batteries face disconnection issues with electrode tabs due to the swelling phenomenon, which can lead to stress accumulation and potential fire or explosion, necessitating a solution to prevent tab disconnection during battery degradation or impact.
Innovation Solution
The electrode tabs include an excess length part supported by a clip with a ligation part, allowing for sliding movement during swelling, reducing stress on the welding point and preventing disconnection, and incorporating a friction-reducing structure and insertion guiding part for smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode tab is rigidly fixed to the electrode assembly, then the electrical connection is stable, but the electrode tab will be subjected to excessive stress during swelling and may disconnect
Solution Approach 1:
The electrode tab is designed with a flexible portion that can dynamically adjust its position during battery swelling. The tab includes a first portion rigidly connected to the electrode assembly and a second portion that can move relative to the first portion, allowing the system to adapt to volume changes while maintaining electrical connection.
Solution Approach 2:
The electrode tab is divided into multiple segments: a first electrode tab portion rigidly connected to the electrode assembly, a second electrode tab portion that can move relative to the first portion, and a third portion connected to the current collector. This segmentation allows different parts to perform different functions - maintaining connection while accommodating swelling.
2Strength
If the electrode tab is made flexible to accommodate swelling, then stress is reduced, but the electrical connection stability may be compromised
Solution Approach 1:
The flexible portion of the electrode tab is designed with controlled flexibility - it can move to accommodate swelling but maintains sufficient rigidity to ensure stable electrical connection. The flexibility is optimized based on the expected swelling range while maintaining connection reliability.
Solution Approach 2:
Different portions of the electrode tab have different mechanical properties. The first portion connected to the electrode assembly has higher rigidity for stable connection, while the second portion has controlled flexibility to accommodate swelling, and the third portion maintains conductivity. Each segment's properties are optimized for its specific function.
3Adaptability or versatility
If excess length is added to the electrode tab, then swelling accommodation is improved, but the device complexity increases
Solution Approach 1:
The electrode tab is segmented into functional portions rather than simply adding excess length. The first portion provides stable connection, the second portion accommodates movement through controlled flexibility, and the third portion ensures conductivity. This segmentation achieves swelling accommodation through functional design rather than excessive material.
Solution Approach 2:
Instead of adding static excess length, the solution creates a dynamically adaptable structure where the second portion of the electrode tab can actively move and flex to accommodate swelling. This dynamic approach provides adaptability without requiring excessive material or complex additional components.
Data Source
AI summary
The disclosed technology relates to a secondary battery, including: an electrode assembly in which a plurality of unit cells are stacked and an electrode terminal. In one example, respective electrode tabs of the unit cells, which extend from the electrode assembly, are gathered together and electrically connected to an electrode terminal of the secondary battery, and the electrode tab of each unit cell includes an excess length part corresponding to the swelling of the electrode assembly.