Secondary Cell Terminal Rivet for External Welding and Sealing
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Solution Overview
Problem
The increasing demand for rechargeable batteries, particularly lithium-ion batteries, requires improvements in energy performance, manufacturing efficiency, and assembly simplification, as current designs and manufacturing processes face challenges in optimizing production speed and cost.
Innovation Solution
A terminal rivet for cylindrical secondary cells with a shaft extending through the casing to contact a current collecting plate, featuring a head that forms an external terminal, a gasket for fluid and electrical insulation, and a design that enhances thermal and electrical conductivity, allowing for simplified assembly and improved heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal rivet with gasket and head is used to seal and electrically insulate the opening, then fluid-tight sealing and electrical insulation are improved, but device complexity increases
Solution Approach 1:
The gasket integrates multiple functions into a single component: fluid sealing (retaining electrolyte), electrical insulation (isolating head from casing), and thermal resistance (managing heat). This merging reduces the number of separate parts needed while achieving reliable sealing and insulation.
Solution Approach 2:
The gasket serves multiple purposes simultaneously: it seals the opening against fluid leakage, provides electrical insulation between conductive parts, and manages thermal properties. This multi-functionality improves reliability without requiring additional dedicated components for each function.
2Reliability
If the head is made larger than the opening to close the opening and form external terminal, then electrical conductivity and terminal function are improved, but manufacturing precision requirements increase
Solution Approach 1:
The head is designed with specific dimensional properties (larger than the opening) only where needed to achieve electrical insulation and terminal function, while the shaft maintains precise dimensions for fitting through the opening. This localized quality approach ensures electrical conductivity requirements are met without unnecessarily increasing precision requirements across the entire rivet.
3Strength
If the shaft is deformed to retain the rivet in place, then mechanical strength and retention are improved, but ease of manufacture decreases
Solution Approach 1:
The shaft is designed to undergo controlled deformation during assembly to achieve retention. The deformation process transforms the shaft from a simple cylindrical form to a configured shape that mechanically locks the rivet in place, providing strong retention while maintaining manufacturing simplicity through a single-component design.
4Productivity
If welding is performed from outside the cell, then productivity and manufacturing efficiency are improved, but manufacturing precision requirements increase
Solution Approach 1:
Instead of welding from inside the cell (conventional approach), the invention enables welding from outside the cell through the head. This inverted approach improves productivity by eliminating the need for internal access and complex positioning, while the head's design provides adequate tolerance for achieving reliable welds from the external side.
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 terminal rivet provides a reliable, efficient, and cost-effective solution by ensuring a fluid-tight seal, enhancing electrical conductivity, and simplifying the manufacturing process, thereby improving energy performance and assembly efficiency of secondary cells.
Implementation Method 1
The part of the gasket around the shaft thus forms a fluid seal for the opening in the casing to retain liquid electrolyte within the cell
Implementation Method 2
The part of the gasket between the head of the rivet and the end of the casing around the opening electrically insulates the head of the rivet from the casing
Implementation Method 3
The head of the terminal rivet can thus act as an external terminal for the cell by being electrically conductive (e.g., formed from a metal such as aluminum or an alloy thereof) and electrically connected, via the first end of the shaft, to a current collecting disc
Implementation Method 4
When manufacturing the cell, the terminal rivet may be welded to the current collecting disc to thereby form a reliable electrical and mechanical connection therebetween. Such welding (or soldering) may be performed by any suitable means such as a welding laser, ultrasonic welding, capacitor discharge welding, or the like
Data Source
AI summary
There is disclosed herein a terminal rivet (100), a cylindrical secondary cell (6000) comprising such a terminal rivet (100), and a method (1000) of manufacturing such a secondary cell (6000). The rivet (100) comprises a shaft (110) configured to extend axially (A) through a casing of the secondary cell to thereby electrically contact a current collecting plate of the secondary cell at a first end (110a) of the shaft (110) and a head (120) arranged at a second end (110b) of the shaft (110), configured to form an external terminal for the cylindrical secondary cell. The head (120) comprises a central region (122) and a first welding region (124) arranged around said central region (122), wherein the first welding region (124) is recessed relative to said central region (122). The first end (110a) of the shaft (110) comprises a second welding region (114), aligned along the axis (A) of the shaft with the first welding region (124), and recessed towards the first welding region (124).