Sealed Battery Terminal Riveting Design for Vibration Resistance
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Solution Overview
Problem
Sealed batteries face issues with the rivet member and terminal joint coming apart under severe conditions such as vibration or shock, especially in ultralow temperature environments, due to partial disconnection and increased resistance.
Innovation Solution
A sealed battery design featuring a battery case with insulating materials and terminals with an insertion hole having an inclined surface and recess, where the second terminal's shaft part is inserted and crushed to create a riveted joint, ensuring the terminals do not easily come apart, even when made of different materials with varying coefficients of expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the rivet member and terminal are joined by simple riveting without additional structural features, then the manufacturing process is simple, but the joint strength is insufficient under severe conditions such as vibration or shock
Solution Approach 1:
The insertion hole is designed with non-uniform cross-sectional area, creating a localized recess portion with smaller area and a larger portion with greater area. This local quality variation allows the rivet member to be anchored more securely in the larger portion while maintaining a compact overall structure, significantly improving joint strength without substantially increasing complexity
Solution Approach 2:
The insertion hole transitions from a simple cylindrical shape to a three-dimensional structure with varying cross-sectional areas along its length. This dimensional change creates the recess portion that provides mechanical interlocking, enhancing joint strength while adding only minimal structural complexity
2Strength
If the rivet member and terminal are joined by welding, then the joint strength is high, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The patent replaces the thermal/mechanical welding process with a purely mechanical riveting system. The insertion hole's varying cross-sectional area creates a mechanical anchor that provides sufficient joint strength without requiring welding equipment, procedures, or the associated complexity and time
Solution Approach 2:
The insertion hole structure itself provides the joining function through its geometric design. The recess portion with smaller cross-sectional area and the larger portion work together to mechanically lock the rivet member in place, making the joint structure self-sufficient without requiring additional welding processes
3Adaptability or versatility
If the rivet member and terminal are made of different materials, then the adaptability is improved, but the joint becomes prone to coming apart due to different coefficients of expansion and contraction
Solution Approach 1:
The insertion hole's varying cross-sectional area creates a mechanical interlock that physically restrains the rivet member. This mechanical constraint overrides the effects of differential thermal expansion between different materials, allowing reliable joints even when the terminal and rivet member are made of dissimilar materials with different expansion coefficients
Solution Approach 2:
The recess portion of the insertion hole provides a mechanical anchor that accommodates dimensional changes. The three-dimensional geometry with varying cross-sectional areas allows the structure to absorb thermal expansion and contraction stresses while maintaining joint integrity across different materials
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 enhances joint strength to withstand vibrations and shocks, maintains resistance at the joint, and prevents disconnection in extreme temperatures without the need for welding, ensuring reliable battery performance.
Implementation Method 1
A leading end of the shaft part is crushed and riveted on the first terminal
Implementation Method 2
The second rim includes an inclined surface. A diameter of the insertion hole at the inclined surface increases gradually in a direction away from the one or more insulating materials
Implementation Method 3
At least a portion of the shaft part reaches into the recess in the inclined surface of the first terminal
Data Source
AI summary
A first terminal including an insertion hole is placed on one side of a lid of a battery case with one or more insulating materials interposed therebetween. An inner circumferential surface defining the insertion hole includes a first rim and a second rim at a position farther away from the one or more insulating materials than the first rim is. The second rim includes an inclined surface with a recess that includes a bottom at a position set back inside the first terminal from the inclined surface. The second terminal has a shaft part inserted through a mounting hole of the lid and the insertion hole. A leading end of the shaft part is riveted, and at least a portion of the shaft part reaches into the recess.