Pyrotechnic Electric Line Cutter for High Voltage Busbar Disconnection
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Solution Overview
Problem
In electric vehicle crashes, the high voltage electrical currents from batteries pose a hazard for occupants and emergency personnel due to the risk of electrocution and combustion, as manual shut-off methods are unreliable and unsafe.
Innovation Solution
An electric line cutter device with a pyrotechnic igniter and insulating piston that rapidly disrupts high voltage busbar current flow, using a two-part housing and filter system to extinguish arcs and cool plasma, ensuring automatic disconnection within milliseconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a manual off switch is used to disrupt high voltage current flow, then the system structure remains simple, but the reliability is poor because the driver may be incapacitated and emergency personnel may not be able to safely access the switch
Solution Approach 1:
The system automatically detects crashes through sensors and triggers the pyrotechnic igniter without requiring human intervention. The high voltage disruption system serves itself by using onboard sensors to detect crash conditions and automatically activate the cutting mechanism, ensuring reliable operation even when occupants are incapacitated.
Solution Approach 2:
The manual mechanical switch operation is replaced with an automated pyrotechnic system. The pyrotechnic igniter uses chemical energy to propel the piston and cut the busbar, substituting the mechanical action of a human-operated switch with an automated chemically-driven mechanism that responds to sensor signals.
2Speed
If a pyrotechnic igniter with piston is used to rapidly disrupt current flow, then the speed of current interruption is improved to under 2 milliseconds, but the device complexity increases with additional components
Solution Approach 1:
The pyrotechnic igniter provides a rapid, periodic impulse of energy to propel the piston forward and cut the busbar within milliseconds. This impulsive action is ideal for crash scenarios where extremely fast current interruption is required, delivering the necessary force in a single rapid stroke rather than a gradual process.
Solution Approach 2:
The system changes the physical state of materials through the pyrotechnic reaction, converting chemical energy to thermal and mechanical energy. The rapid heating and expansion of pyrotechnic materials generates the high-velocity piston movement needed for millisecond-level busbar disruption, utilizing parameter changes to achieve extreme speeds.
3Reliability
If the busbar is rigidly held between upper and lower housing to maintain circuit connection, then the electrical connectivity is improved, but the ability to rapidly disconnect current is worsened
Solution Approach 1:
The busbar is designed with a predetermined fracture location that segments it into two parts upon piston impact. The fracture location creates a weak point that allows the busbar to break into separate segments, enabling rapid disconnection while maintaining secure holding of the stub ends in the housing after separation.
Solution Approach 2:
The busbar is pre-positioned and rigidly held between the upper and lower housing with the fracture location prepared in advance. The compression force pre-loads the busbar at the fracture point, so that when the piston impacts, the predetermined break point fails immediately, enabling ultra-fast disconnection without requiring complex mechanical release mechanisms.
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
Effectively interrupts high voltage currents up to 16 kA and 1000 V in under 2 milliseconds, minimizing hazards by automatically disconnecting power and extinguishing arcs, thus protecting vehicle occupants and emergency responders.
Implementation Method 1
The igniter is electrically activated in the event of a signal from a sensor. In a preferred embodiment, the electric line cutter device is configured to be used in a vehicle capable of generating high voltages wherein the electric line cutter device is activated by the sensor in the event of a vehicle crash. The igniter preferably is a pyrotechnic device and further comprises a propellant charge squib.
Implementation Method 2
The piston is at least partially formed as an insulator to prevent electric discharge.
Implementation Method 3
The electric line cutter device preferably has a filter to capture debris generated during the breaking of the busbar and in particular to cool down and deionize the plasma.
Data Source
AI summary
An electric line cutter device for high voltage busbars has a two-part housing, a piston, an igniter and a busbar. The upper housing includes a cylinder, cuboid or prism chamber. The lower housing also includes a cylinder, cuboid or prism chamber. The piston is contained inside one of either the upper housing chamber or the lower housing chamber. Upon igniting the igniter, the piston breaks a portion of the busbar moving the piston and the portion of the busbar into the opposite chamber thereby stopping the electric current flow. The piston is at least partially formed as an insulator to prevent electric discharge. The piston design together with chamber design includes integrated “squeeze areas” and “blow channels” for the appearing arc. A channel system outside or from inside the piston allow the pyro gases to push the arc plasma into a filter system to cool down the gases.