Battery Foil Interconnect Welding for Stronger Edge and Spot Joints
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Solution Overview
Problem
Existing methods of welding stacked metal foil layers often result in insufficient electrical connectivity and mechanical detachment due to gaps between layers, leading to failure modes such as decay in electrical connectivity and mechanical disconnection at weld points.
Innovation Solution
The method involves sandwiching metal foil layers between top and bottom end plates, aligning their edges, and compressing them to form a stack, which is then welded using a combination of spot welds for mechanical connection and edge welds for enhanced electrical connectivity, employing specific materials like titanium and aluminum alloys to ensure strong mechanical and electrical interconnections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If penetration welding is used to join metal foil layers, then electrical connectivity is improved, but gaps between layers cause burning or incomplete melting
Solution Approach 1:
The patent introduces a weldable material layer (intermediary substance) between the metal foil layers to be joined. This intermediary material fills gaps between layers and serves as a mediator that enables complete melting through the stack during welding, preventing burning while ensuring electrical connectivity. The weldable material has properties that facilitate welding while maintaining electrical conductivity.
Solution Approach 2:
The patent changes the physical and chemical parameters of the joining system by selecting specific weldable materials with appropriate melting points, electrical conductivity, and wetting characteristics. By controlling material composition and welding parameters (temperature, time, pressure), the process achieves complete penetration melting without burning the foil layers.
2Manufacturing precision
If tight fixturing of metal foil layers is applied to prevent gaps, then welding quality is improved, but device complexity increases
Solution Approach 1:
The weldable material layer acts as a compensating intermediary that reduces sensitivity to positioning errors and gaps. By providing a material that flows and fills voids during welding, the need for extremely tight fixturing and perfect alignment is reduced, thereby simplifying the fixture design while maintaining weld quality.
3Ease of manufacture
If conventional welding methods are used on stacked metal foils, then manufacturing simplicity is maintained, but mechanical detachment occurs at weld points
Solution Approach 1:
The patent creates a composite structure at the weld interface by combining the metal foil layers with the weldable material layer. This composite joint provides both mechanical strength and electrical conductivity, preventing detachment while maintaining manufacturing simplicity. The weldable material forms a metallurgical bond that strengthens the connection between layers.
4Object-affected harmful factors
If edge welding is used instead of penetration welding, then layer burning is prevented, but electrical connectivity is insufficient
Solution Approach 1:
The patent merges the advantages of both penetration welding and edge welding by using a weldable material layer that enables controlled penetration melting while the welding approach can be selected as edge or penetration based on requirements. The weldable material ensures complete melting through the stack without burning the foils, achieving both connectivity and protection.
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 approach achieves both improved mechanical strength and electrical conductivity, exceeding conventional systems by providing a robust and reliable connection that prevents relative movement and ensures consistent performance over time.
Implementation Method 1
welding the end plates and compressed metal foil layer stack together
Data Source
AI summary
Devices and methods disclosed herein relate to forming superior mechanical and electrical connections between stacks of foils such as those used in electrochemical cells. The connections described herein use multiple weld types and choice of materials to promote electrical and mechanical connectivity using separate weld types.