Battery Terminal Flange Cladding for Strong Dissimilar-Metal Welding
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Solution Overview
Problem
Conventional lithium-ion secondary battery cells with external terminals face challenges in securing welding strength between a shaft and a flange when they are made of different metals, leading to potential weaknesses in electrical conduction and reliability.
Innovation Solution
The electric storage device employs a clad material for the flange with multiple metal layers, including one layer made of the same metal as the shaft, ensuring strong welding by swaging and maintaining resistance even after damage, with a specified contact area and dimensions to secure connecting strength and conduction performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the flange is made of a different metal from the shaft to enable welding of other members, then the flange can be welded to bus bars and other members, but the welding strength between the shaft and flange deteriorates
Solution Approach 1:
The flange is constructed as a composite structure with a first metal layer (e.g., aluminum alloy) and a second metal layer (e.g., copper or copper alloy) having different electrical conductivities. This layered composite material enables the flange to be welded to both the shaft (made of the same metal as the second layer) and external conductors (bus bars), while maintaining strong welding strength at both interfaces.
Solution Approach 2:
Different regions of the flange have different metal compositions optimized for their specific functions: the second metal layer (copper or copper alloy) contacts the shaft and provides excellent electrical conductivity and welding strength, while the first metal layer (aluminum alloy) provides structural support and enables welding to external conductors. This local differentiation of material properties resolves the contradiction between weldability and welding strength.
2Ease of manufacture
If the flange is made of a different metal from the shaft, then the flange can be welded to other members, but the electrical conduction reliability deteriorates
Solution Approach 1:
The flange uses a composite structure with a copper or copper alloy layer (second layer) that provides excellent electrical conductivity for reliable conduction to the shaft, combined with an aluminum alloy layer (first layer) that enables welding to external conductors. This composite material approach maintains high electrical conduction reliability while enabling versatile welding capability.
Solution Approach 2:
The flange's second metal layer is specifically designed with high electrical conductivity (copper or copper alloy) to ensure reliable electrical conduction to the shaft, while the first metal layer (aluminum alloy) provides structural properties and weldability to external members. This local optimization of material properties resolves the contradiction between weldability and conduction reliability.
3Adaptability or versatility
If the shaft and flange are made of different metals, then the flange can be welded to bus bars of different materials, but the welding strength between shaft and flange decreases
Solution Approach 1:
The flange is constructed as a composite material with a first metal layer (aluminum alloy) and a second metal layer (copper or copper alloy). This composite structure enables the flange to be welded to shafts made of the same metal as the second layer while also providing adaptability to weld to bus bars of various materials, all while maintaining strong welding strength at the shaft-flange interface through the metallurgically compatible second layer.
Solution Approach 2:
The flange employs local differentiation of material properties where the second metal layer (copper or copper alloy) is specifically positioned at the shaft interface to ensure strong welding strength and excellent electrical conductivity, while the first metal layer (aluminum alloy) provides structural support and enables welding to various external conductors. This local quality approach resolves the contradiction between versatility and welding strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively secures welding strength and conduction reliability between the shaft and flange, even when made of different metals, maintaining electrical performance and reliability under various conditions.
Implementation Method 1
the flange and the shaft are connected to each other with the shaft being swaged
Implementation Method 2
one of the plurality of metal layers of the flange at one end in the passing direction is made of the same metal in kind as the metal of the shaft, and is welded to the shaft
Data Source
AI summary
This embodiment includes an electrode assembly; a case for housing the electrode assembly; and an external terminal made of a metal and disposed on the case, in which the external terminal includes: a flange extending along an outer surface of the case; and a shaft extending from the flange to pass through the case and be conductive with the electrode assembly, the flange is made of a clad material having a plurality of metal layers layered in a passing direction of the shaft, each adjacent ones of the plurality of metal layers are made of different metals in kind, and one of the plurality of metal layers of the flange at one end in the passing direction is made of the same metal in kind as the metal of the shaft, and is welded to the shaft.