Electrolytic Capacitor Two-Step Aging for Longer Maintenance Cycles
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Solution Overview
Problem
Aluminum electrolytic capacitors used in Implantable Cardioverter Defibrillators (ICDs) require frequent maintenance charge cycles due to the susceptibility of aluminum oxide to dielectric relaxation and chemical attack by the electrolyte, leading to shortened ICD longevity.
Innovation Solution
A two-step aging process for aluminum electrolytic capacitors, involving impregnation with a first electrolyte, a first aging process to grow a pseudo-bochmite oxide layer, impregnation with a second electrolyte, a final aging process, and finally impregnation with a third electrolyte, which extends the maintenance cycle and increases battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-step aging process is used, then the manufacturing process is simple and quick, but the capacitor requires frequent maintenance charge cycles (3-6 months) due to aluminum oxide susceptibility to dielectric relaxation and chemical attack
Solution Approach 1:
The aging process is divided into two distinct steps: a first aging process that grows a pseudo-bochmite oxide layer, and a second aging process that completes the aluminum oxide layer formation. This segmentation allows each step to optimize for its specific function, resulting in a more durable capacitor that requires maintenance only every 9-12 months instead of every 3-6 months.
Solution Approach 2:
The first aging process performs a preliminary action by growing a pseudo-bochmite oxide layer before the second aging process completes the aluminum oxide layer formation. This preliminary layer provides a foundation that reduces subsequent dielectric relaxation and chemical attack, extending the maintenance cycle.
2Loss of time
If the capacitor is stored at room temperature without charging, then energy is conserved, but the charge time increases over time due to deformation from dielectric relaxation and chemical attack
Solution Approach 1:
The two-step aging process provides beforehand cushioning by creating a more stable oxide layer structure before the capacitor is put into service. This pre-conditioning reduces the magnitude of dielectric relaxation and chemical attack that occur during storage, thereby minimizing charge time increases over the capacitor's lifetime.
3Duration of action of moving object
If aluminum electrolytic capacitors are used in ICDs, then the desired high voltage and energy density are achieved, but the battery life is shortened due to frequent maintenance charge cycles
Solution Approach 1:
By segmenting the aging process into two steps, the capacitor achieves improved long-term stability that reduces the frequency of maintenance charge cycles from every 3-6 months to every 9-12 months. This directly extends ICD longevity and conserves battery life over the device's operational lifetime.
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 two-step aging process significantly extends the maintenance cycle of aluminum electrolytic capacitors, potentially up to 5 years in storage and 9 months in the body, thereby extending the battery life of ICDs by one year or more.
Implementation Method 1
aging the first impregnated capacitor using a first aging process to form a first aged capacitor
Implementation Method 2
impregnating an aluminum electrolytic capacitor with a first electrolyte to form a first impregnated capacitor
Implementation Method 3
impregnating the first aged capacitor with a second electrolyte to form a second impregnated capacitor
Data Source
AI summary
A method of manufacturing an electrolytic capacitor includes impregnating an electrolytic capacitor with a first electrolyte to form a first impregnated capacitor, aging the first impregnated capacitor using a first aging process to form a first aged capacitor, impregnating the first aged capacitor with a second electrolyte to form a second impregnated capacitor, the second electrolyte being different from the first electrolyte, aging the second impregnated capacitor using a final aging process to form a final aged capacitor, and impregnating the final aged capacitor with a third electrolyte.