Pyrotechnic Switch for DC Power Short-Circuiting

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Solution Overview

Problem

Existing DC power voltage sources based on electrochemical accumulators face challenges with high costs and energy losses due to the use of MOSFET switches and their controls, which are also unreliable for maintaining a closed state without command, especially in safety-critical applications like electric vehicles.

Innovation Solution

A safety switch comprising conductive electrodes and a pyrotechnic element that, upon explosion, welds the conductive element to the electrodes, ensuring a durable and reliable electrical connection, capable of handling high-intensity currents and maintaining contact even during short-circuits, thereby reducing losses and ensuring safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If MOSFET switches and controls are used in battery cells, then the battery can be isolated for safety or maintenance, but the cost increases due to heat sinks and control electronics

Engineering Contradiction:
Improvesafety isolation capabilityVSAvoidcost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the MOSFET switch and control electronics from the battery cell structure, retaining only the essential safety isolation function through a simplified mechanical or chemical mechanism, thereby eliminating heat sinks and control electronics while maintaining safety capabilities

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention employs a simple, low-cost sacrificial element (such as a fuse or chemical barrier) that can be easily replaced if needed, replacing expensive and complex MOSFET assemblies while achieving the same safety isolation function

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If MOSFET switches are used to isolate battery cells, then safety isolation is achieved, but energy losses and parasitic heating occur even when switches are open

Engineering Contradiction:
Improvesafety isolation capabilityVSAvoidenergy losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts the MOSFET switch from the system and replaces it with a passive isolation mechanism that introduces no electrical resistance or parasitic heating, eliminating energy losses entirely while maintaining safety isolation functionality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the electrical MOSFET switching mechanism with a mechanical or chemical isolation method that does not involve current flow through switching components, thereby eliminating parasitic heating and energy losses associated with MOSFET operation

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If normally closed switches are used to maintain open state, then probability of fault is reduced, but permanent losses occur during operation

Engineering Contradiction:
Improvefault probabilityVSAvoidpermanent losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent inverts the switching logic by using a normally open configuration with a fail-closed mechanism, where the default state is open (no current flow, no losses) and the switch closes only when safety isolation is required, eliminating permanent losses while maintaining reliability

Inventive Principle:
Principle #13The other way round (Inversion)

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 solution provides a reliable, durable, and efficient means to secure DC power supplies by ensuring electrical contact without breaking, even under high current conditions, while minimizing energy losses and controlling the risks associated with pyrotechnic elements through controlled parameters.

Implementation Method 1

a pyrotechnic element (17) including an explosive (171), the explosion of which causes the electrically conductive element (15) to be driven into contact with the second electrode (12)

Methodology Applied
Scientific EffectExplosion: Explosion

Implementation Method 2

the conductive element to be welded to the second electrode (12) to form a bond strong and durable electrically conductive between the first and second electrodes

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3044803B1Switch for short-circuiting a direct-current power source
Publication Date: 2018.10.10 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3044803B1 patent drawingFigure 1~6
  • EP3044803B1 patent drawingFigure 7~10
  • EP3044803B1 patent drawingFigure 11~15

AI summary

The invention relates to a switch (1) comprising: first and second electrically conductive electrodes (11, 12); an electrically conductive element (15); an electrically insulating medium (162) separating the first and second electrodes and separating the electrically conductive element from the second electrode; a pyrotechnic element (17) including an explosive (171), the explosion of said explosive causing the electrically conductive element (15) to move and come into contact with the second electrode (12) and the conductive element to be welded to the second electrode, such as to form an electrically conductive link between the first and second electrodes.