Lead Wool Anode Fused Connection for Oxygen Sensor
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Solution Overview
Problem
In oxygen sensing cells with lead wool anodes, the introduction of a vent hole to prevent thermal shock leads to an aerobic environment, causing lead oxide buildup and electrical connection breakdown between the anode and current collector, reducing sensor lifespan and causing 'glitching' issues.
Innovation Solution
Fused connections are created between lead wool anodes and current collectors using a conductive medium like solder or metal-loaded epoxy, excluding oxygen and enhancing bonding, which can be achieved through methods like wave soldering, resistance welding, or chemical plating, ensuring stable electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a vent hole is added to the cell body to prevent thermal shock, then thermal stability is improved, but electrical connection reliability deteriorates due to lead oxide buildup
Solution Approach 1:
A nickel mesh intermediary is introduced between the lead wool anode and the current collector. The mesh provides multiple contact points that maintain electrical connectivity even when lead oxide forms on the anode surface, acting as a mediator that ensures continuous electrical path despite oxidation
Solution Approach 2:
The patent creates a protected environment around the lead wool anode by enclosing it within the cell body, limiting oxygen exposure. This inert environment approach prevents extensive oxidation of the lead anode, thereby maintaining electrical connection reliability while allowing the vent hole to function for thermal stability
2Stability of the object's composition
If a vent hole is added to the cell body, then pressure balancing is improved, but sensor lifespan deteriorates due to anode oxidation
Solution Approach 1:
The cell body design creates a protected environment that limits oxygen access to the lead wool anode. This inert environment protection slows down oxidation processes, extending sensor lifespan while the vent hole maintains pressure balancing functionality
Solution Approach 2:
The nickel mesh acts as an intermediary layer that maintains electrical connectivity through oxidized regions. This allows the sensor to continue functioning even when some oxidation occurs, effectively extending the operational lifespan despite the presence of the vent hole
3Ease of manufacture
If pressure contact is used between nickel foil and lead wool, then ease of manufacture is improved, but electrical connection stability deteriorates in aerobic environments
Solution Approach 1:
The nickel mesh serves as an intermediary contact layer between the nickel foil and lead wool. It provides multiple distributed contact points that maintain electrical stability even when oxidation occurs, while still allowing for relatively simple manufacturing processes
Solution Approach 2:
The electrical connection assembly uses a composite structure combining nickel foil, nickel mesh, and lead wool. This multi-material approach leverages the advantages of each material: the foil for structural support, the mesh for stable electrical contact, and the lead wool for electrochemical function
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 solution prevents premature electrical connection breakdown and extends the sensor's lifespan by maintaining a stable, anaerobic environment and ensuring reliable connectivity between lead wool anodes and external electrical connections.
Implementation Method 1
Fused connections are created between lead wool anodes and current collectors using a conductive medium like solder or metal-loaded epoxy
Implementation Method 2
build up of lead oxide on the surface of the lead wool anode is promoted which in turn creates an electrical connection breakdown
Implementation Method 3
Its function is to balance pressure differences within the cell experienced during transition of the cell between different ambient temperatures / pressures
Implementation Method 4
the only path is that of the capillary hole in the cap which exposes the working electrode to an increased gas flow
Data Source
Figure 1~3
Figure 2A~2B
AI summary
A lead wool electrode for an electro-chemical cell can be fused to a metallic collector to provide an electrical connection therebetween. Various methods of fusion such as thermal, electrical or chemical can be used.