Wet Electrolytic Capacitor Recessed Anode Stabilization
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Solution Overview
Problem
High voltage electrolytic capacitors used in implantable medical devices, such as implantable cardioverter defibrillators, face challenges in size reduction and stabilization due to the need for larger casings to accommodate restraints for the tantalum anode, which increases the overall device size and may not provide sufficient contact for effective stabilization.
Innovation Solution
A wet electrolytic capacitor design featuring a planar anode with a recessed portion and a restraint that fits into the recessed portion, allowing for secure stabilization without increasing the capacitor's dimensions, using an anodically oxidized pellet formed from pressed and sintered powder and a metal substrate coated with an electrochemically-active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a restraint is placed between the outer surface of the anode pellet and the casing wall to stabilize the anode, then the anode stabilization is improved, but the casing height must be increased to accommodate the restraint, which increases the overall capacitor size
Solution Approach 1:
The restraint is nested within a recessed portion of the anode structure, allowing the restraint to be positioned inside the anode's own geometry rather than requiring additional external space. This nesting approach enables the restraint to contact the anode surface effectively while avoiding the need to increase the overall capacitor height.
Solution Approach 2:
Instead of placing the restraint in the vertical dimension (between anode top surface and casing wall), the invention utilizes the horizontal dimension by creating a recessed portion in the anode structure where the restraint can be positioned laterally, thereby stabilizing the anode without increasing the vertical height of the capacitor.
2Stability of the object's composition
If the casing height is increased to accommodate a restraint, then the anode can be stabilized, but the overall size of the implantable device increases, defeating the purpose of using a planar anode for size reduction
Solution Approach 1:
The restraint is nested within the anode's recessed portion, utilizing existing structural space rather than adding external volume. This allows effective anode stabilization while maintaining the compact dimensions of the planar anode design, thereby preventing increase in the overall implantable device volume.
Solution Approach 2:
The recessed portion creates a localized region in the anode structure specifically designed to house the restraint, concentrating the stabilization function in a specific area rather than requiring global dimensional increases. This local modification maintains the overall compact form factor of the capacitor.
3Device complexity
If a restraint is placed without sufficient contact with the anode surface, then the structure is simplified, but the anode stabilization effectiveness is reduced
Solution Approach 1:
The recessed portion provides a precisely fitted space for the restraint, ensuring maximum contact area between the restraint and anode surface. This nested configuration naturally increases contact effectiveness without requiring complex restraint structures or additional components.
Solution Approach 2:
The combination of the anode material forming the recessed portion and the restraint material creates a composite stabilization system where the geometric interlocking provides enhanced contact and stabilization effectiveness while keeping the overall structure relatively simple.
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 design achieves stable operation under shock and vibration without increasing the capacitor's size, enhancing the energy density and reducing the overall size of implantable medical devices while maintaining effective electrical performance.
Implementation Method 1
The planar anode includes an anodically oxidized pellet formed from a pressed and sintered powder
Implementation Method 2
an anodically oxidized pellet formed from a pressed and sintered powder
Implementation Method 3
The cathode includes a metal substrate coated with an electrochemically-active material
Data Source
AI summary
A wet electrolytic capacitor is provided. The capacitor includes a planar anode formed from a pressed and sintered powder, a cathode that includes a metal substrate that is coated with an electrochemically-active material, and a working electrolyte in communication with the planar anode and cathode. The planar anode has a recessed portion formed in at least one of its surfaces. The capacitor also includes at least one restraint that is in contact with the recessed portion and has a shape that generally corresponds with a shape of the recessed portion. The recessed portion of the planar anode allows for stabilization of the planar anode with via a restraint without increasing the dimensions of the capacitor.