Power Battery Top Cap Dissimilar Metal Joint Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In power battery top cap structures, the joint surface between copper and aluminum sections of the electrode column is prone to cracking or breaking due to stress forces, leading to potential liquid spillage, especially in batteries with smaller diameters, as existing welding methods struggle to effectively connect these dissimilar materials.
Innovation Solution
A power battery top cap structure design where the upper and lower sections of the electrode column are formed from different base metals (copper and aluminum) and joined using processes like cold rolling, hot rolling, or friction welding, with a conductive plate and seal member configuration that distributes stress forces and prevents direct pulling on the joint surface, ensuring a stable electrical connection and sealing the joint from electrolyte exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dissimilar metals (copper and aluminum) are joined using conventional welding methods, then electrical conductivity and material compatibility are improved, but joint strength and reliability deteriorate due to cracking and breaking at the joint surface
Solution Approach 1:
The patent introduces an intermediate connection structure consisting of a first connection block (aluminum) and a second connection block (copper) that are separately welded to the upper and lower sections of the electrode column. This intermediary connection system allows each connection block to be welded to matching material sections, avoiding direct dissimilar metal welding at critical stress points and preventing joint surface cracking.
2Reliability
If stress forces are applied to the electrode column joint, then electrical connection stability is improved, but joint integrity deteriorates due to cracking at the joint surface between dissimilar metals
Solution Approach 1:
The patent segments the electrode column into upper and lower sections made of different materials (aluminum and copper respectively), and introduces separate connection blocks for each section. This segmentation allows stress forces to be distributed to different connection blocks rather than concentrating at a single joint surface between dissimilar metals, preventing cracking while maintaining electrical connection stability.
3Ease of manufacture
If friction welding is used to join copper and aluminum sections, then material compatibility is improved, but manufacturing complexity increases due to the need for specialized welding processes
Solution Approach 1:
The patent applies local quality by making each connection block from a specific material matching its adjacent electrode column section (aluminum connection block for aluminum section, copper connection block for copper section). This allows each welding operation to use simple, compatible material joining rather than complex dissimilar metal welding processes, reducing manufacturing complexity while ensuring material compatibility.
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 effectively concentrates stress forces on the upper section, preventing cracks or breaks at the joint surface, maintains a stable electrical connection, and reduces electrical resistance, while ensuring the joint is sealed from electrolyte exposure, thus enhancing the structural integrity and performance of the power battery.
Implementation Method 1
the upper section and the lower section are joined together by way of friction welding
Implementation Method 2
joined using processes like cold rolling, hot rolling, or friction welding
Implementation Method 3
The horizontal extending portion is disposed between a lower surface of the top cap piece and the step portion
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A top cap structure for a power battery is provided. The power battery top cap structure includes a first and second electrode assemblies, and a top cap piece. The first electrode assembly includes a first electrode column having an upper and lower sections, a first seal member and a first connection block. The upper section and the first connection block are formed from a first base metal. The lower section is formed from a second base metal different from the first base metal. The upper section includes a step portion, and the lower section is joined with a bottom surface of the upper section below the top cap piece. The first seal member includes a horizontal extending portion. The horizontal extending portion is disposed between a lower surface of the top cap piece and the step portion. The top portion of the upper section connects with the first connection block.