Electrode Tab Elliptical Hole Structure for Crack Resistance
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Solution Overview
Problem
Pouch type secondary batteries face issues with electrode tab disconnection due to external and internal forces during manufacturing, connection, and usage, primarily because of the weak structure and thin metal composition of the electrode tabs.
Innovation Solution
An electrode assembly with an elliptical hole in the electrode tab adjacent to the overlapping portion with the electrode lead, where the hole's long axis aligns with the tab's protrusion direction, reducing stress concentration and enhancing crack resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the electrode tab is made of thin metal film to match the thin electrode plates, then the battery structure remains simple and manufacturing is easier, but the electrode tab becomes vulnerable to disconnection under external and internal forces
Solution Approach 1:
The electrode tab is constructed as a composite structure combining a thin metal film base layer with an additional reinforcement layer. This composite design maintains the simplicity of the thin-film structure while adding mechanical strength through the reinforcement layer, resolving the contradiction between structural simplicity and tab strength.
Solution Approach 2:
The reinforcement layer is applied selectively to specific regions of the electrode tab, particularly at the connection point with the electrode plate and the protruding tip. This localized reinforcement strengthens vulnerable areas without requiring the entire tab to be thicker, maintaining overall structural simplicity while addressing strength deficiencies where needed.
2Strength
If the electrode tab is made thicker to increase strength, then resistance to disconnection improves, but the manufacturing complexity and difficulty of matching with thin electrode plates increases
Solution Approach 1:
The electrode tab structure is segmented into two functional layers: a thin metal film base layer that maintains compatibility with thin electrode plates, and a separate reinforcement layer that provides additional strength. This segmentation allows each layer to be optimized independently, simplifying manufacturing compared to creating a uniformly thick tab.
Solution Approach 2:
The reinforcement layer is applied to the metal film base layer in advance, before the electrode tab is connected to the electrode plate. This preliminary reinforcement ensures that the tab has sufficient strength during handling and assembly operations, while the thin base layer continues to match the electrode plate thickness for proper electrical contact.
3Productivity
If conventional electrode tabs are used without reinforcement, then the manufacturing process remains simple and fast, but disconnection occurs frequently during manufacturing and usage
Solution Approach 1:
The reinforcement layer is applied to the electrode tab in advance during the electrode assembly manufacturing process, before the tab is connected to the electrode plate. This preliminary reinforcement ensures high connection reliability during subsequent handling, welding, and usage, while the process is integrated into existing manufacturing workflows to maintain productivity.
Solution Approach 2:
The electrode tab uses a composite structure with a thin metal film base layer and a reinforcement layer. This composite design provides enhanced connection reliability by preventing disconnection under stress, while the thin base layer maintains compatibility with standard manufacturing processes for thin-film electrodes, preserving manufacturing speed.
Data Source
AI summary
An electrode assembly according to one exemplary embodiment of the present disclosure includes a unit cell including a positive electrode plate, a separator and a negative electrode plate, an electrode tab that is protruded from at least one of the positive electrode plate and the negative electrode plate, and an electrode lead that is connected to the electrode tab, wherein an elliptical hole is formed in a portion of the electrode tab adjacent to an overlapping portion of the electrode tab and the electrode lead.