Ceramic Enclosed Thermal Battery Sealing

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Solution Overview

Problem

Glass seals in thermal batteries allow for slow leakage of gases and moisture, degrading hydroscopic materials and limiting shelf life, especially in extreme environmental conditions like deep-sea applications.

Innovation Solution

The enclosure, including the portion through which terminals pass, is made of ceramic material, eliminating the need for glass seals and significantly reducing gas and moisture leakage by using a non-porous, electrically-non-conductive ceramic material for the entire enclosure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If glass seals are used to seal terminals to the enclosure, then the terminals can be sealed to the enclosure, but gases and moisture slowly leak into the battery, degrading hydroscopic materials and limiting shelf life

Engineering Contradiction:
Improvesealing effectivenessVSAvoidshelf life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the material parameter of the enclosure from metal to ceramic, which fundamentally alters the sealing mechanism. Ceramic materials provide inherent gas and moisture impermeability without requiring glass seals, thereby eliminating the leakage pathway that limits shelf life while maintaining sealing effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent removes the glass seal component from the system by using a ceramic enclosure that inherently seals terminals without additional sealing elements. This extraction of the glass seal eliminates the interface between dissimilar materials (glass-metal) that creates leakage pathways, thereby extending shelf life while maintaining reliable sealing.

Inventive Principle:
Principle #2Taking out (Extraction)

2Strength

If stainless steel enclosure is used, then the enclosure provides structural strength, but the electrically-conductive material requires insulative material around electrical components to prevent contact

Engineering Contradiction:
Improveenclosure strengthVSAvoidinsulation requirements
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent changes the electrical conductivity parameter of the enclosure material from conductive (stainless steel) to non-conductive (ceramic). This material parameter change eliminates the need for insulative barriers around electrical components, reducing device complexity while the ceramic material maintains sufficient structural strength for the application.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs ceramic material that combines structural strength with electrical non-conductivity in a single material system. This composite property eliminates the need for separate insulation components, thereby reducing device complexity while maintaining the required enclosure strength.

Inventive Principle:
Principle #40Composite materials

3Reliability

If glass seals are used between terminals and metal enclosure, then the terminals can be sealed, but the leakage rate of gases and moisture is high compared to ceramic enclosures

Engineering Contradiction:
Improvesealing functionVSAvoidgas and moisture leakage
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the material composition parameter from glass-metal composite sealing to monolithic ceramic sealing. Ceramic materials provide inherent impermeability to gases and moisture at the molecular level, eliminating the micro-porous pathways present in glass seals and thereby dramatically reducing substance loss while maintaining the sealing function.

Inventive Principle:
Principle #35Parameter changes

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 solution substantially reduces gas and vapor leakage, enhances the battery's durability in extreme environments, and ensures electrical isolation, making it suitable for high voltage applications and reducing the need for additional insulation.

Implementation Method 1

the entire enclosure of the battery is not electrically conductive... electrically-non-conductive ceramic material

Methodology Applied
Scientific EffectElectrical non-conduction: Electrical Resistance

Implementation Method 2

non-porous, electrically-non-conductive ceramic material... gas and vapor leakage through the enclosure is greatly reduced

Methodology Applied
Scientific EffectNon-porous barrier: Porosity

Data Source

PatentEP2856534B1Ceramic enclosed thermal battery
Publication Date: 2018.10.17 EAGLEPICHER TECHNOLOGIES LLC
  • EP2856534B1 patent drawingFigure 1
  • EP2856534B1 patent drawingFigure 2
  • EP2856534B1 patent drawingFigure 3~4

AI summary

At least a portion of the enclosure of a thermal battery is formed of a ceramic material that is non-porous and electrically-non-conductive. The thermal battery includes at least one cell, a squib that when activated causes the at least one cell to become active, and an enclosure that surrounds the at least one cell and the squib. Squib terminals and battery terminals extend through the enclosure and are electrically connected to the squib and to the at least one cell, respectively. At least the portion of the enclosure through which the squib and battery terminals extend is formed of the ceramic material. The enclosure includes a container and a header. At least the header is made from the ceramic material, and preferably both the container and the header are made from the ceramic material. The ceramic material may include AI2O3.