Recessed Cell Header Sealing for Compact Implantable Batteries
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Solution Overview
Problem
Conventional electrochemical cell headers fail to provide sufficient interior volume while maintaining a compact external size, and they struggle with reliable sealing to prevent electrolyte leakage and incursion of fluids, especially in implantable medical devices exposed to bodily fluids.
Innovation Solution
The design incorporates a recessed header with a planar plate and perpendicular side wall, featuring stepped structures on the lower surface for enhanced sealing, along with a peripheral band for a fluid-tight seal, and uses separator pouches made from microporous materials to isolate components and prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a conventional header design is used, then the external size can be compact, but the interior volume is insufficient and sealing reliability is poor
Solution Approach 1:
The header is segmented into multiple functional zones: a recessed portion forming a cavity above the planar plate, stepped structures on the lower surface creating multiple sealing levels, and a peripheral band extending around the periphery. This segmentation allows each zone to serve specific purposes (volume expansion, sealing, connection) thereby increasing interior volume while maintaining manageable structural complexity through functional differentiation.
Solution Approach 2:
The header design extends into the vertical dimension with a recessed portion forming a cavity above the planar plate, and incorporates stepped structures that create multiple elevation levels on the lower surface. This multi-level three-dimensional configuration maximizes interior volume within a compact footprint without proportionally increasing overall header height, effectively utilizing spatial dimensionality to resolve the volume-complexity contradiction.
2Reliability
If sealing structures are added to prevent fluid leakage, then reliability improves, but device complexity increases
Solution Approach 1:
The sealing function is segmented across multiple structures: stepped structures on the lower surface providing primary sealing levels, a peripheral band extending around the periphery providing secondary sealing, and the recessed cavity configuration containing electrolyte. This segmentation distributes the sealing function across multiple simplified elements rather than requiring a single complex sealing mechanism, thereby improving reliability while keeping individual components manageable.
Solution Approach 2:
The peripheral band is configured to extend around the periphery of the planar plate and is designed to be sealed to both the upper surface and the cell casing. This band structure acts as a flexible sealing element that can accommodate minor manufacturing tolerances and thermal expansion, providing reliable fluid-tight sealing without requiring complex rigid sealing mechanisms.
3Reliability
If separator pouches are used to isolate components, then fluid leakage prevention improves, but manufacturing complexity increases
Solution Approach 1:
Separator pouches made from microporous flexible materials are used to enclose the anode and cathode assemblies. These pouches act as flexible barriers that prevent fluid leakage and electrical short circuits while allowing ion transport through their microporous structure. The flexible nature of these pouches simplifies the assembly process compared to rigid separation structures, as they can be easily formed and sealed around the electrode components.
Solution Approach 2:
The separator pouches are constructed from microporous materials that combine multiple functions: mechanical separation of electrodes, fluid leakage prevention, and ion transport enablement. This composite material approach consolidates multiple separation and protection functions into a single component, reducing the number of separate parts needed and simplifying the overall manufacturing process while maintaining high reliability.
Data Source
AI summary
A header for an electrochemical cell includes a planar plate configured to cover an internal volume of the electrochemical cell, and a side wall extending from an upper surface of the planar plate in a direction perpendicular to the upper surface. The header also includes a recess defined by the upper surface of the planar plate and the side wall, and a first step and a second step on a lower surface of the planar plate, the first step and the second step configured to seal the internal volume. An aspect of an electrochemical cell includes an anode, a cathode, a cell casing and the header.