Dual Separator Layout for Compact Implantable Electrochemical Cells

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Solution Overview

Problem

Conventional separator and insulator systems in electrochemical cells take up excessive space, making it challenging to prevent direct physical contact between opposite polarity electrodes and electrical components as cell sizes decrease, particularly in critical applications like implantable medical devices.

Innovation Solution

A novel separator system using a primary microporous woven or non-woven polymeric separator envelope for the cathode and a free-standing secondary separator bag that acts as a physical barrier between the anode and cathode, as well as between the positive and negative terminals, to prevent physical contact while allowing ion transfer and reducing volume occupancy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple separator layers and insulators are used to prevent physical contact between opposite polarity electrodes, then reliability is improved, but volume occupancy increases

Engineering Contradiction:

Improveprevention of short-circuitVSAvoidvolume occupied by separator and insulator system

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The primary separator envelope completely encloses the cathode, and the secondary separator bag encloses the primary separator envelope subassembly. This nested configuration provides redundant protection against short-circuits while minimizing the overall volume occupied by the separator system, as each layer serves multiple protective functions simultaneously.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The secondary separator bag serves multiple functions: it provides redundant protection against short-circuits between electrodes, acts as a physical barrier between opposite polarity terminal components, and maintains structural integrity of the separator system. This multi-functionality reduces the need for separate insulator components, thereby reducing overall volume occupancy.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Volume of moving object

If cell size is reduced to meet compact device requirements, then productivity and adaptability are improved, but the risk of direct physical contact between opposite polarity components increases

Engineering Contradiction:

Improvecell sizeVSAvoidprevention of direct contact between electrodes

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The nested separator envelope configuration provides robust physical separation between opposite polarity electrodes and terminal components even in reduced cell sizes. The primary separator envelope and secondary separator bag create multiple barriers that maintain reliable isolation despite the smaller overall cell dimensions.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The separator envelopes are constructed from thin, flexible microporous polymeric materials that provide effective physical barriers while occupying minimal space. These thin film structures enable reliable electrode isolation in compact cell designs where traditional bulkier separator systems would be impractical.

Inventive Principle:

Principle #30Flexible shells and thin films

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 proposed separator system effectively prevents physical contact between opposite polarity electrodes and terminals, enhancing reliability and reducing the overall size of the electrochemical cell, particularly beneficial for compact devices like implantable medical devices by providing redundancy and space efficiency.

Implementation Method 1

a separator material that prevents physical contact but allows for ion transfer

Methodology Applied

Scientific EffectPorosity: Porosity

Implementation Method 2

The first separator envelope is heat sealed at a seam to completely enclose the cathode

Methodology Applied

Scientific EffectHeat sealing: Welding

Data Source

PatentUS11799172B2Dual separator design for medical implantable electrochemical cells

Publication Date: 2023.10.24 GREATBATCH LTD

AI summary

An electrochemical cell comprises a casing having an open- ended container closed by a lid. An anode and cathode are housed inside the casing. The cathode housed inside a primary separator envelope is electrically connected to a positive polarity terminal pin electrically isolated from the casing by a glass-to- The anode is electrically connected to the casing metal seal.serving as a negative terminal. The primary separator enveloping the cathode is contained in a secondary separator comprising an open-ended bag-shaped member extending to an open annular edge. The open annular edge of the secondary separator resides between the cathode electrically connected to the terminal pin and the anode electrically connected to the casing. An electrolyte provided in the casing activates the anode and cathode.