Electrode Feedthru Crimp Pin Elastomer Sealing
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Solution Overview
Problem
Existing feedthru assemblies for electrolytic capacitors, particularly in implantable medical devices like ICDs, face challenges with manual assembly requiring skilled operators, high variability in sealing properties, contamination risks, and low tensile strength, leading to yield decreases and capacitor failures.
Innovation Solution
A feedthru assembly design featuring a ferrule with a stepped-shape and an elastomer structure, using a crimp pin and electrode wire of different materials for enhanced strength, and an injection molding process to encapsulate the electrode assembly, ensuring robustness and reduced leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual assembly method is used for feedthru assembly, then low leak rate and robust assembly are achieved, but highly skilled operator is required and automated manufacturing is prevented
Solution Approach 1:
The feedthru assembly is divided into separate components: a ferrule portion with internal threading, a seal portion made of elastomer, and an electrode wire. These segments can be manufactured separately using automated processes and then assembled through controlled operations, enabling partial automation while maintaining reliability.
Solution Approach 2:
The elastomer seal portion acts as an intermediary between the ferrule and the electrode wire, providing sealing functionality that is easier to manufacture automatically. The seal portion includes a seal cavity that receives the electrode wire, creating a reliable seal through the elastomer's material properties rather than complex manual assembly steps.
2Reliability
If rubber feedthru material is used, then sealing is provided, but high variability in material sealing properties and contamination risk occur
Solution Approach 1:
The feedthru assembly uses a composite structure combining a metal ferrule portion with an elastomer seal portion. This composite approach allows the metal ferrule to provide structural integrity and electrical connection, while the elastomer provides consistent sealing properties. The controlled manufacturing of each material type reduces variability and contamination risk compared to using rubber alone.
3Reliability
If high purity aluminum wire is used for electrode, then compatibility with capacitor chemistry is achieved, but low tensile strength and easy breaking occur
Solution Approach 1:
The electrode assembly combines high purity aluminum wire (for chemical compatibility) with a metal ferrule (for mechanical strength). The aluminum wire maintains compatibility with the capacitor's electrolyte chemistry, while the ferrule portion provides the necessary tensile strength to prevent breaking during manufacturing and handling. The two materials work together in a composite structure that leverages the advantages of each.
Solution Approach 2:
The ferrule acts as an intermediary between the fragile high purity aluminum wire and the external environment. It provides mechanical protection and strength to the wire while allowing the wire to maintain its chemical compatibility function. The ferrule's threaded structure also enables secure attachment without directly stressing the aluminum wire.
4Extent of automation
If injection molding method is used for feedthru assembly, then automated manufacturing is enabled, but low tensile strength and easy damage occur
Solution Approach 1:
The injection molding process is used to manufacture the seal portion separately from the ferrule and electrode wire. This segmentation allows the elastomer seal to be automatically formed with consistent properties, while the metal components are manufactured using processes better suited for achieving high strength. The assembled structure combines the automatically formed seal with the stronger metal components.
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 easier manufacturing, increased tensile strength, and improved sealing, reducing the risk of electrolyte leakage and contamination, thus enhancing the reliability and durability of the capacitors.
Implementation Method 1
an elastomer structure, configured to encapsulate at least a portion of the electrode assembly
Implementation Method 2
A crimp pin, formed of a second material different from the first material, is connected to the electrode wire
Data Source
AI summary
Disclosed herein is an electrode feedthru assembly for an electronic device and method of manufacturing. The feedthru assembly includes a ferrule, an electrode assembly, and an elastomer. The ferrule includes a bore through which the electrode assembly is positioned. The electrode assembly includes an electrode wire attached to a crimp pin. The crimp pin includes a crimp terminal portion and a pin terminal portion, the crimp terminal portion crimped to the a portion of the electrode wire to form a connected portion of the electrode assembly. The elastomer is disposed in the bore of the ferrule between the ferrule and the electrode assembly. The elastomer is configured to electrically isolate the ferrule from the electrode assembly and to encapsulate at least the connected portion of the electrode assembly.