Nested Enclosure for Implantable Device Battery Volume

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Solution Overview

Problem

Implantable medical devices face a challenge in maximizing the volume of their power sources, such as battery assemblies, without increasing the overall device volume, which affects the operational life and comfort of the patient.

Innovation Solution

The implementation of a dual-layer conductive enclosure structure where one enclosure contains the electronics and the other, with a nested metal sheet configuration, houses the power source, providing redundant sealing through welds and hermetically sealed feedthroughs to maximize battery cell volume within a given device size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the volume of the power source is increased to extend operational life, then the operational life is improved, but the overall device volume increases which reduces patient comfort

Engineering Contradiction:
Improveoperational lifeVSAvoiddevice volume
Core Design Contradiction:
Duration of action of moving objectVSVolume of moving object

Solution Approach 1:

The patent applies nesting by placing the first conductive enclosure containing electronics inside the second conductive enclosure containing the power source. This nested configuration allows both components to occupy overlapping spatial volumes, maximizing the power source volume within the overall device envelope without proportionally increasing the external dimensions, thereby extending operational life while maintaining patient comfort.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Device complexity

If a single conductive enclosure is used to contain both electronics and power source, then the device construction is simplified, but the packaging efficiency is reduced limiting power source volume

Engineering Contradiction:
Improveconstruction simplicityVSAvoidpower source volume
Core Design Contradiction:
Device complexityVSVolume of stationary object

Solution Approach 1:

The patent segments the device into two separate conductive enclosures: a first enclosure for electronics and a second enclosure for the power source. This segmentation allows each component to be optimized independently for its specific function and volume requirements, enabling the power source to occupy maximum volume within the second enclosure while the electronics are contained in the smaller first enclosure, thereby improving packaging efficiency without excessive complexity.

Inventive Principle:
Principle #1Segmentation

3Duration of action of moving object

If the power source volume is maximized within a fixed device size, then the operational life is extended, but the construction integrity and sealing reliability may be compromised

Engineering Contradiction:
Improveoperational lifeVSAvoidconstruction integrity
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The nested enclosure configuration provides inherent structural support and distribution of mechanical stresses. The inner first enclosure is supported by the outer second enclosure, and both are secured together through attachment features, distributing loads and preventing deformation that could compromise sealing integrity, thus maintaining reliability while allowing maximum power source volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent incorporates attachment features including welds, mechanical fasteners, or interference fits between the two enclosures that pre-establish secure connections before the device is implanted. These pre-configured attachment mechanisms ensure that the enclosures remain firmly connected under various operational conditions, preventing separation or deformation that could compromise the hermetic sealing and construction integrity.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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

This approach increases the operational life of the device by up to 50% by allowing a larger battery cell volume within the same overall device dimensions, while maintaining reliable construction integrity.

Implementation Method 1

The second enclosure further includes at least two welds that extend around an entire perimeter of the header plate, the first of which joins the header plate to the edge of the first sheet and provides a seal for the power source within the second enclosure

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 2

the header assembly of the second enclosure includes a header plate having a hermetically sealed feedthrough extending therethrough, wherein the feedthrough electrically couples the power source to the electronics

Methodology Applied
Scientific EffectHermetic sealing:

Data Source

PatentEP3082952B1Implantable medical device construction
Publication Date: 2017.11.29 MEDTRONIC INC
  • EP3082952B1 patent drawingFigure 1A
  • EP3082952B1 patent drawingFigure 1B
  • EP3082952B1 patent drawingFigure 2A

AI summary

An implantable medical device (300) includes two conductive enclosures (310, 320) that are attached together, wherein the first enclosure (310) contains electronics (14), and the second enclosure (320) contains a power source (316). The second enclosure (320), all or a portion of which is located outside the first enclosure, includes an inner layer (321), an outer layer (322), and a header plate (351A), all of which are configured to provide redundant sealing for the power source. The inner and outer layers, formed by separate metal sheets nested one within the other, are preferably in direct mechanical and electrical contact. The first sheet (321), which forms the inner layer, approximately conforms to a profile of the power source, located therein, and the second sheet (322), which forms the outer layer, conforms to a profile of the first sheet. An insulative housing (201), which contains connector contacts of the device, is directly secured to the first and second conductive enclosures, for example, by mounting brackets (26). A first weld (27) extends around an entire perimeter of the header plate and joins the header plate (351A) to the edge of the first sheet (321), providing a seal for the contained power source. A second weld (25) extends around an entire perimeter of the header plate and joins the header plate (351A) to the second sheet (322), in proximity to the edge thereof, providing a redundant seal for the contained power source.