Bipole Frame Rivet Assembly for Low-Resistance Bipolar Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bipolar batteries face issues of high electrical resistance and electrolyte communication due to inadequate solder joint fill in the bipole frame, and solder alloys with low reflow temperatures exhibit higher corrosion rates.
Innovation Solution
A solid rivet connection is used to join lead sheets on both sides of the bipole frame, with the rivet being compressed or forged to ensure complete fill of the through holes, and a tin-lead alloy with low tin concentration is employed to minimize corrosion and enhance joint strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder joints are used to join lead sheets on the bipole frame, then electrical connection is established, but inadequate fill causes high electrical resistance and electrolyte communication between cells
Solution Approach 1:
The patent changes the joining method from soldering to mechanical deformation (riveting). The rivet shaft is deformed plastically to fill the through-hole completely, eliminating the fill quality issues inherent in soldering processes while maintaining electrical conductivity through the metallic rivet material and welding.
Solution Approach 2:
The patent replaces the thermal-chemical soldering process with a mechanical deformation process. The rivet shaft undergoes plastic deformation when compressed or forged to form the second head, mechanically filling the through-hole and creating a reliable electrical and structural connection without relying on solder flow and solidification.
2Temperature
If solder alloys with low reflow temperatures are used to work with polymer bipole frames, then processing temperature is reduced, but corrosion rates increase
Solution Approach 1:
The patent extracts the problematic solder alloy material and replaces it with a rivet structure made of corrosion-resistant materials. The rivet can be made from stainless steel or other corrosion-resistant alloys that do not require low-temperature processing, thereby eliminating the corrosion issue entirely while maintaining the ability to join lead sheets to polymer frames through mechanical deformation and welding.
Solution Approach 2:
The rivet serves as a permanent, non-consumable joining element that replaces the consumable solder material. Unlike solder that is consumed during the joining process, the rivet remains as a structural and electrical component throughout the battery's service life, providing ongoing corrosion resistance.
3Reliability
If solid rivet connection is used to ensure complete fill of through holes, then electrical resistance is reduced and electrolyte leakage is prevented, but manufacturing complexity increases
Solution Approach 1:
The rivet shaft is prepared in advance with a specific geometry (smaller diameter shaft portion) that enables easy insertion into the through-hole before the final deformation step. This preliminary configuration simplifies the assembly process by separating the insertion and forming operations, making the overall process more controllable and less complex.
Solution Approach 2:
The rivet structure is designed to self-fill the through-hole during the deformation process. As the distal end is compressed or forged to form the second head, the shaft material plastically deforms and automatically fills the entire through-hole volume, eliminating the need for separate filling operations or quality control steps to ensure complete fill.
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 solid rivet connection reduces electrical resistance, prevents electrolyte leakage, and extends the battery's service life by minimizing corrosion and stress concentration, allowing for longer-lasting battery applications.
Implementation Method 1
compressing a distal end of the shaft to form a second head of the electrical joint that is on the second surface of the bipole frame and to completely fill the through hole with the shaft
Implementation Method 2
a tin-lead alloy including less than 10% tin by weight
Data Source
AI summary
A method of assembling a bipole frame assembly for a bipolar battery, includes: providing a bipole frame including first and second opposite surfaces and a plurality of through holes; receiving a shaft of an electrical joint in each through hole such that a first head of the electrical joint is on the first surface of the bipole frame; and compressing a distal end of the shaft to form a second head of the electrical joint that is on the second surface of the bipole frame, the second head having a diameter greater than that of the shaft and the shaft completely filling the through hole.