Battery Terminal Weld Geometry for Current Flow and Low Spatter
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Solution Overview
Problem
Insufficient current flow and excessive weld spatter in the electrical connection between the connecting sheet and the terminal post of a secondary battery lead to disconnection, temperature rise, and increased internal resistance, posing safety issues.
Innovation Solution
A secondary battery design with a connecting sheet and terminal post where the welding part penetrates through the welding surface, ensuring a specific relationship between the effective fusion width, welding surface area, and track length to maintain sufficient current flow while minimizing spatter, thereby enhancing safety performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the welding part is made larger to ensure sufficient current flow, then the current flow is improved, but the weld spatter increases and internal resistance increases
Solution Approach 1:
The patent optimizes the geometric parameters of the welding part, specifically controlling the ratio of effective fusion width to track length within 0.05-5, and the ratio of effective fusion depth to connecting sheet thickness within 0.1-5. These parameter changes enable sufficient current flow while minimizing weld spatter and internal resistance
Solution Approach 2:
The welding part is designed with non-uniform distribution characteristics, where the effective fusion width and depth are concentrated in specific regions. This local quality approach ensures that current flow is sufficient at critical locations while limiting overall spatter generation
2Strength
If the welding part is made larger to prevent disconnection, then the connection strength is improved, but the battery internal resistance increases
Solution Approach 1:
The patent establishes optimal parameter ranges for the welding part geometry: effective fusion width to track length ratio of 0.05-5, and effective fusion depth to connecting sheet thickness ratio of 0.1-5. These parameter changes achieve strong connections while minimizing internal resistance
Solution Approach 2:
The patent replaces traditional mechanical welding approaches with a controlled welding process that creates a welding part with specific geometric characteristics. This substitution enables achieving both strong connection and low internal resistance through precise control of fusion dimensions
3Reliability
If the welding surface area is increased to improve current flow, then the electrical connection is improved, but the weld spatter and manufacturing complexity increase
Solution Approach 1:
The patent optimizes the relationship between welding surface area and welding track characteristics by controlling the effective fusion width, effective fusion depth, and track length ratios. This enables improved electrical connection without excessive increase in welding surface area or manufacturing complexity
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
The design guarantees adequate current flow and connection strength, reduces spatter, and prevents separation, thus improving the safety and performance of the battery by avoiding disconnection and resistance issues.
Implementation Method 1
the connecting sheet is fixed to the terminal post by welding, and a welding part is formed between the connecting sheet and the terminal post
Data Source
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AI summary
A secondary battery is disclosed, which includes a connecting sheet and a terminal post; the connecting sheet has a welding surface; the terminal post and the connecting sheet are stacked, and the welding surface faces the terminal post; the connecting sheet is fixed to the terminal post by welding, and a welding part is formed between the connecting sheet and the terminal post; at least part of the welding part is provided in an interior of the connecting sheet and at least part of the welding part is provided in an interior of the terminal post; the welding part penetrates through the welding surface, and forms a welding track on the welding surface.