Power Battery Top Cap with Segmented Connection Block
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Solution Overview
Problem
The existing power battery top cap structures face challenges in maintaining stable contact electrical resistance due to fluctuations at the copper-aluminum transition interface, especially under external factors like shaking and impacting, which can lead to unstable current output and increased heat generation.
Innovation Solution
A power battery top cap structure is designed with a first electrode assembly and a second electrode assembly, where the connection blocks are formed by the same material as the busbar, and a compound portion is bonded with a main body using processes like laser welding or riveting, creating a stable power transmission surface by forming a metallurgical bond with a high bonding rate and tensile strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single material (aluminum or copper) is used for both connection blocks to simplify welding, then manufacturing complexity is reduced, but it becomes impossible to directly connect copper and aluminum electrode columns without additional transition structures
Solution Approach 1:
The connection block is divided into two distinct portions: a first portion made of aluminum material and a second portion made of copper material. This segmentation allows each portion to be optimally matched with its corresponding electrode column (aluminum with aluminum, copper with copper) while eliminating the need for complex transition structures.
Solution Approach 2:
Different regions of the connection block are assigned different materials based on local requirements. The first portion uses aluminum material to match the aluminum electrode column, while the second portion uses copper material to match the copper electrode column, achieving optimal electrical and mechanical properties in each local region.
2Reliability
If copper and aluminum materials are welded together using traditional methods, then direct connection is achieved, but welding difficulty increases significantly due to different melting points and specific heat capacities
Solution Approach 1:
The connection block is segmented into aluminum and copper portions, eliminating the need to weld dissimilar metals together. Each material is welded only to like materials (aluminum to aluminum, copper to copper), significantly reducing welding difficulty while maintaining connection reliability.
Solution Approach 2:
The aluminum portion of the connection block acts as an intermediary between the aluminum electrode column and the copper portion, facilitating smooth current transition without requiring direct copper-aluminum welding. This intermediary structure simplifies the manufacturing process while ensuring reliable electrical connection.
3Weight of moving object
If the compound portion is made thin to reduce weight, then weight reduction is achieved, but bonding strength and structural integrity may be compromised
Solution Approach 1:
The thickness of the compound portion is optimized to a specific range that balances weight reduction with bonding strength requirements. This parameter optimization ensures the structure is as light as possible while maintaining sufficient mechanical and electrical performance.
Solution Approach 2:
The connection block uses a composite structure combining aluminum and copper materials, each contributing their superior properties. This composite design achieves weight reduction through material selection while maintaining bonding strength through appropriate thickness and bonding process optimization.
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 avoids fluctuations in contact electrical resistance and enhances the structural integrity and sealing functionality, ensuring stable power transmission and reduced heat generation across the transition interface.
Implementation Method 1
a compound portion is bonded with a main body using processes like laser welding or riveting, creating a stable power transmission surface by forming a metallurgical bond with a high bonding rate and tensile strength
Implementation Method 2
the connection section is rivetedly connected to the second connection hole and the first electrode column is engaged with the step portion
Data Source
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AI summary
A top cap structure for a power battery includes a first electrode assembly and a top cap piece. The first electrode assembly includes a first electrode column and a first connection block. The first connection block includes a main body and a compound portion that are bonded together. A base metal material of the main body is different from the base metal materials of the first electrode column and the compound portion. The compound portion includes a first connection hole and the main body includes a second connection hole. A top portion of the first electrode column includes a connection section. The connection section passes through the top cap piece, the second connection hole, and the first connection hole, and extends from the first connection hole. The connection section and the compound portion are welded together. The connection section is riveted to the second connection hole.