Multi-Layer Clad Electrode Tab for Secondary Battery
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Solution Overview
Problem
Existing secondary batteries face challenges in reducing heat generation and preventing short circuits, particularly in high-power applications, due to high resistance in electrode tabs, which can lead to thermal runaway and malfunctions.
Innovation Solution
The use of a five-layer clad negative electrode tab with a structure of Ni—Cu—Ni—Cu—Ni, where the sum of Cu layers is less than 30% of the total thickness, reduces resistance and improves weldability, and further post-plating with nickel enhances stability and prevents short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layer or three-layer electrode tab is used, then the structure is simple and manufacturing is easy, but the resistance is high leading to heat generation and short-circuit risks
Solution Approach 1:
The patent applies composite materials by using a five-layer clad structure (Ni-Cu-Ni-Cu-Ni) instead of conventional single-layer or three-layer tabs. This multi-layer composite structure combines nickel and copper layers to achieve both low electrical resistance (reducing heat generation) and high weldability, while preventing short circuits between electrodes. The alternating Ni-Cu layers provide optimal balance between conductivity and structural integrity.
Solution Approach 2:
The electrode tab is segmented into five distinct layers with alternating materials (Ni-Cu-Ni-Cu-Ni). This segmentation allows each layer to perform its specific function: copper layers provide electrical conductivity, while nickel layers provide weldability and structural stability. The segmented structure reduces overall resistance compared to homogeneous single-layer tabs.
2Reliability
If the Cu layer thickness is increased to reduce resistance, then electrical conductivity improves, but weldability deteriorates
Solution Approach 1:
The patent applies local quality by creating non-uniform distribution of materials within the tab structure. The five-layer clad (Ni-Cu-Ni-Cu-Ni) has varying local compositions where copper layers are positioned to provide conductivity where needed, while nickel layers are positioned at the welding surfaces and intermediate positions to ensure weldability. This local differentiation resolves the contradiction between conductivity and weldability.
Solution Approach 2:
The composite Ni-Cu-Ni-Cu-Ni structure allows simultaneous optimization of conductivity and weldability. The copper layers (with higher conductivity) are interspersed with nickel layers (with better weldability), creating a composite that exhibits both properties. The total copper content is controlled to be less than 30% of total thickness, ensuring weldability while maintaining low resistance.
3Reliability
If a five-layer Ni-Cu-Ni-Cu-Ni clad structure is used, then resistance is reduced and weldability is improved, but manufacturing complexity increases
Solution Approach 1:
The five-layer clad structure is prepared in advance as a pre-manufactured component before being attached to the electrode. This preliminary preparation of the multi-layer clad allows the complex structure to be produced once and then simply applied to electrodes, reducing the manufacturing complexity during battery assembly. The clad is manufactured separately with precise layer control, then integrated into the battery system.
Data Source
AI summary
A secondary battery includes an electrode assembly including a first electrode plate including a first electrode tab, a second electrode plate including a second electrode tab, and a separator interposed between the first electrode plate and the second electrode plate, a case accommodating the electrode assembly, and a cap assembly covering a top portion of the case. Any one of the first electrode tab and the second electrode tab includes a multi-layer clad electrode tab including two copper (Cu) layers.