Pyrotechnic Circuit Breaker Chamber Material for Arc Insulation

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Solution Overview

Problem

Existing pyrotechnic circuit breakers face issues with high leakage currents, prolonged opening times, and insufficient insulation resistance due to the use of flowable insulating materials and internal plastic walls without adequate flame retardants, which are not compatible with automotive applications and degrade performance.

Innovation Solution

Incorporating a flame retardant into the plastic material of the internal chamber walls, particularly those exposed to the electric arc, using polymers like polyamide and glass fibers, and combining this with silicone in specific proportions to enhance insulation resistance and reduce leakage currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional circuit breakers are used, then electrical overload protection is provided, but the device complexity increases and reliability decreases due to multiple failure-prone components

Engineering Contradiction:
Improvecircuit breaker reliabilityVSAvoidcircuit breaker complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex mechanical components (bimetallic strip, spring mechanism, trip lever, button) from the circuit breaker design. By removing these traditional overload protection mechanisms and replacing them with a simple pyrotechnic device, the invention achieves both reduced complexity and improved reliability while maintaining the essential circuit breaking function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical overload detection and actuation system with a pyrotechnic (chemical) system. The bimetallic strip and spring mechanism are substituted with a pyrotechnic charge that responds to electrical current, eliminating mechanical failure points and simplifying the overall device structure.

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

2Reliability

If circuit breakers with many components are used, then electrical protection functions are achieved, but the loss of substance increases due to oil or other materials requiring disposal

Engineering Contradiction:
Improvecircuit breaker reliabilityVSAvoidoil disposal requirement
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent removes the oil-filled enclosure and other material-intensive components from traditional circuit breakers. By extracting these substance-heavy elements and replacing them with a minimal pyrotechnic device, the invention eliminates the need for oil disposal and reduces material waste while maintaining protective functions.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The pyrotechnic circuit breaker employs a simple, inexpensive, and environmentally benign design that does not require long-term maintenance or disposal of hazardous materials like oil. The device uses minimal consumable materials (pyrotechnic charge, fuse wire) that are non-toxic and do not require special disposal procedures.

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

3Reliability

If traditional circuit breaker components are used, then electrical overload protection is provided, but the manufacturing precision requirements increase due to tight tolerances

Engineering Contradiction:
Improvecircuit breaker reliabilityVSAvoidcomponent tolerance requirements
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent eliminates components that require precision manufacturing (bimetallic strips, spring mechanisms, adjustable trip settings) and replaces them with a pyrotechnic device that relies on chemical properties rather than mechanical precision. This extraction of precision-dependent components dramatically reduces manufacturing tolerance requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention transitions from mechanical parameters (spring tension, bimetallic curvature, lever positioning) to chemical parameters (pyrotechnic composition, fuse wire resistance). This parameter change allows for less stringent manufacturing tolerances because chemical properties can be controlled more easily than mechanical dimensions.

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

The solution provides a pyrotechnic circuit breaker with fast opening times, high insulation resistance, and effective leakage current interruption, ensuring reliable operation even under high current and voltage conditions.

Implementation Method 1

A pyrotechnic charge is connected in series with a fuse wire and enclosed in a housing. The circuit breaker is actuated by passing current through the fuse wire.

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

A pyrotechnic charge is connected in series with a fuse wire and enclosed in a housing. The circuit breaker is actuated by passing current through the fuse wire.

Methodology Applied
Scientific EffectPyrotechnic reaction: Pyrolysis

Data Source

PatentEP4186086B1Pyrotechnic circuit breaker and motor vehicle comprising such a circuit breaker
Publication Date: 2026.05.06 AUTOLIV DEV AB
  • EP4186086B1 patent drawingFigure 1~2
  • EP4186086B1 patent drawingFigure 3~4
  • EP4186086B1 patent drawingFigure 5A~5B

AI summary

Disclosed is a pyrotechnic circuit breaker comprising: - a housing (10), - at least two connection terminals (21, 22); - an internal electrical circuit linking the two connection terminals (21, 22) and consisting, for example, of an electrical conductor; - an opening member (40) that is movable and configured, when moving between an initial position and a final position, to open a section of the internal electrical circuit intended to be opened, thus forming at least two separate conductor portions (32, 33) after opening; - a pyrotechnic actuator (50) for moving the opening member (40) from the initial position to the final position; - an internal chamber (60) receiving the section to be opened, characterised in that the internal chamber includes or contains at least one inner surface formed by a wall consisting of a plastic material including a flame retardant.