Single Metal Busbar for Battery Pack Dissimilar Terminal Joining
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Solution Overview
Problem
The manufacturing cost of high-capacity battery packs is increased due to the use of expensive clad metal busbars, and connection failures occur when trying to weld different metals together, such as copper and aluminum, which is complicated and difficult to achieve.
Innovation Solution
A battery pack design that uses a single metal busbar coupled to electrode terminals of different metals through a clinching, pressing, or riveting process, eliminating the need for complex welding and reducing material costs by using deformation techniques like thermoplastic deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clad metal busbar is used to connect different metals, then connection reliability is improved, but manufacturing cost increases
Solution Approach 1:
The busbar is divided into two distinct connection portions: a first connection portion for connecting to the aluminum electrode terminal and a second connection portion for connecting to the copper electrode terminal. Each portion is designed to work with its specific metal type, allowing reliable connections without requiring expensive clad metal throughout the entire busbar structure.
Solution Approach 2:
Different portions of the busbar have different structural characteristics optimized for their specific connection needs. The first connection portion has features suitable for aluminum welding, while the second connection portion has features suitable for copper welding, allowing each local area to have the appropriate properties for its function without incurring the cost of clad metal throughout.
2Reliability
If welding is used to connect different metals, then electrical connection is achieved, but process complexity increases
Solution Approach 1:
The welding process is segmented into two separate operations: welding the first connection portion to the aluminum terminal and welding the second connection portion to the copper terminal. This segmentation allows each welding operation to be optimized for its specific metal combination, simplifying the overall process compared to attempting to weld dissimilar metals directly together.
Solution Approach 2:
The busbar acts as an intermediary component between the aluminum and copper electrode terminals. By providing separate connection portions for each metal type, the busbar mediates the connection in a way that avoids the complexity of direct dissimilar metal welding while ensuring reliable electrical connectivity through the entire assembly.
3Ease of manufacture
If single metal busbar is used, then manufacturing cost is reduced, but connection reliability may deteriorate
Solution Approach 1:
The busbar is designed with local quality variations where different portions have different structural characteristics optimized for their specific connection requirements. The first connection portion has features optimized for aluminum welding while the second connection portion has features optimized for copper welding, ensuring reliable connections for each metal type without requiring expensive clad metal construction.
Solution Approach 2:
The structural parameters of the busbar are changed locally at different connection portions to optimize for specific metal types. By adjusting geometric parameters such as connection area, thickness, or configuration at different locations along the busbar, reliable connections are achieved for both aluminum and copper terminals while maintaining a cost-effective single-metal construction.
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 design reduces manufacturing costs and prevents connection failures by using a single metal busbar with electrode terminals made of different metals, ensuring reliable electrical coupling without the complexities of welding different metals.
Implementation Method 1
coupling a busbar and an electrode terminal, which are made of different kinds of metals such that welding thereof is not easy to achieve, using deformation (e.g., thermoplastic deformation) by applying pressure using a pressing device (e.g., a press-in device)
Data Source
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AI summary
A battery pack includes a plurality of secondary batteries, each including a first electrode terminal and a second electrode terminal protruding from a cap plate, and a plurality of busbars, each electrically coupling first electrode terminal of one of the secondary batteries and the second electrode terminal of an adjacent one of the secondary batteries, wherein the busbars and the second electrode terminals are forcibly deformed to be coupled to each other, and wherein the busbars are welded to the first electrode terminals.