Segmented Battery Electrodes for MRI-Safe Implantable Devices
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Solution Overview
Problem
Implantable medical devices (IMDs) face hazards in MRI environments due to induced heating and vibration caused by MRI time-varying gradient fields, which can lead to tissue damage and premature device failure.
Innovation Solution
Segmented electrodes for IMD batteries are designed to reduce the size of eddy current loops, minimizing heating and vibration by incorporating high resistance sections and insulating materials to break up surface areas, thereby making the devices MRI Safe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If segmented electrodes with high resistance sections are used, then eddy current loop size is reduced and heating is minimized, but device complexity increases
Solution Approach 1:
The electrode is divided into multiple segments with high resistance sections between them, which breaks up the continuous conductive path and reduces eddy current loop size. This segmentation directly addresses the heating problem by limiting the area over which eddy currents can circulate, while the modular nature of segmentation allows for systematic implementation.
Solution Approach 2:
High resistance sections are strategically placed at specific locations within the electrode structure where they most effectively interrupt eddy current paths. This localized modification of electrical properties allows the design to maintain simplicity in non-critical areas while applying complexity only where necessary to reduce heating.
2Object-affected harmful factors
If insulating materials are incorporated to break up surface areas, then eddy current loops are reduced and vibration is minimized, but manufacturing complexity increases
Solution Approach 1:
Insulating materials are introduced as intermediary elements between conductive electrode segments. These insulating layers serve as mediators that physically separate conductive paths and electrically isolate segments, thereby reducing eddy current loops and associated vibration. The use of standard insulating materials facilitates integration with existing manufacturing processes.
3Reliability
If electrode surface area is reduced through segmentation, then MRI safety is improved, but battery capacity may be reduced
Solution Approach 1:
The electrical resistance parameter is modified by introducing high resistance sections, which changes the eddy current characteristics without necessarily reducing the total electrode surface area available for electrochemical reactions. This parameter change allows the electrode to maintain its capacity while becoming MRI-safe by limiting induced current loops.
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 segmentation of electrodes effectively reduces the response of IMDs to MRI magnetic fields, preventing heating and vibration, ensuring the safety and functionality of the devices during MRI procedures.
Implementation Method 1
Segmented electrodes for IMD batteries are designed to reduce the size of eddy current loops, minimizing heating and vibration
Implementation Method 2
incorporating high resistance sections and insulating materials to break up surface areas
Implementation Method 3
incorporating high resistance sections and insulating materials to break up surface areas
Data Source
AI summary
An implantable device, such as a pacer, defibrillator, or other cardiac rhythm management device, can include one or more MRI Safe components. In an example, the implantable device includes a battery including a first electrode and a second electrode separate from the first electrode. The second electrode includes a first surface and a second surface. The second electrode includes a slot through the second electrode from the first surface toward the second surface. The slot extends from a perimeter of the second electrode to an interior of the second electrode. The slot is configured to at least partially segment a surface area of the second electrode to reduce a radial current loop size in the second electrode.