Cathode Collector Fabrication for Lithium/Oxyhalide Cells
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Solution Overview
Problem
Existing manufacturing processes for lithium/oxyhalide cells struggle to produce cathode collectors with uniform carbonaceous basis weights and minimal thickness variability, leading to inconsistent discharge performance across cells.
Innovation Solution
A continuous feed apparatus using a calender and feed hopper assembly to uniformly distribute and compress acetylene black mixed with PTFE binder onto a perforated nickel or stainless steel substrate, ensuring consistent coating thickness and basis weight across the collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing processes are used for cathode collectors, then production can proceed with existing equipment, but the carbonaceous basis weight and thickness become non-uniform, leading to inconsistent discharge performance
Solution Approach 1:
The invention applies preliminary action by pre-mixing the carbonaceous material with binder and conductive additive in precise proportions before deposition. The continuous feed apparatus pre-configures the coating composition to ensure uniform basis weight and thickness from the start, preventing variability that would require post-processing correction and ensuring consistent discharge performance across all collectors produced.
2Manufacturing precision
If a continuous feed apparatus with calender is used, then uniform coating thickness and basis weight are achieved, but the device complexity increases compared to conventional processes
Solution Approach 1:
The continuous feed apparatus integrates multiple functions into a single system: the calender roller performs both coating deposition and thickness control, while the feed mechanism simultaneously delivers carbonaceous material, binder, and conductive additive in the correct ratios. This multi-functionality achieves precise uniformity without requiring separate equipment for each function, thereby limiting the increase in device complexity.
3Reliability
If strict tolerances for basis weight and thickness are maintained, then consistent discharge performance is achieved, but the manufacturing process becomes more difficult and time-consuming
Solution Approach 1:
The continuous feed apparatus operates continuously to deposit carbonaceous material onto the collector substrate, maintaining steady-state conditions that ensure uniform basis weight and thickness throughout the entire coating process. This continuous operation eliminates interruptions and variations that occur in batch processes, making it easier to maintain strict tolerances and achieve consistent discharge performance across all produced collectors.
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 enables the production of cathode collectors with uniform basis weights and thickness, resulting in consistent discharge performance across lithium/thionyl chloride and lithium/sulfuryl chloride cells, enhancing the reliability and efficiency of the electrochemical cells.
Implementation Method 1
A continuous feed apparatus using a calender and feed hopper assembly to uniformly distribute and compress acetylene black mixed with PTFE binder onto a perforated nickel or stainless steel substrate
Implementation Method 2
The powdered electrically conductive mixture is then continuously fed into a calender and formed into a collector structure by locking to itself through the collector substrate perforations
Data Source
AI summary
An apparatus and method for fabricating continuous cathode collecters for use in lithium/thionyl chloride and lithium/sulfuryl chloride cells is described. The preferred electrically conductive material is acetylene black mixed with a polytetrafluroethylene (PTFE) binder in a dry, powderized form. The collector substrate is a nickel or stainless steel foil that has been expanded into a mesh or otherwise provided with perforations. A centering adjustment of the collector substrate controls loading of the electrically conductive mixture onto each side thereof. The dry, powdered electrically conductive mixture is then continuously fed into the calender and formed into a collector structure by locking to itself through the collector substrate perforations before being cut to size.