Pyrotechnic Switch for Rapid High-Voltage Discharge
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Solution Overview
Problem
Current high-voltage electrical systems in electric and hybrid vehicles pose a safety risk during accidents due to slow discharging of energy from intermediate circuit capacitors, which can lead to fires, and existing solutions are either ineffective or require large, expensive components for rapid discharging.
Innovation Solution
A pyrotechnic switch with a first, second, and third electrical conductor, where the ignition element disconnects the first and second conductors and connects the second and third conductors upon tripping, forming a discharge circuit to rapidly reduce voltage across intermediate circuit capacitors, achieving disconnection and discharging within milliseconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional discharge circuits with non-reactive resistors are used, then the intermediate circuit can be discharged, but the discharge time is too long (5-40 seconds) creating safety risks
Solution Approach 1:
The patent changes the discharge resistance value dynamically by using different resistor configurations. During normal operation, a high resistance limits discharge current. During emergency discharge, the resistance is reduced to a low value to enable rapid energy dissipation within milliseconds, directly resolving the contradiction between safe operation and emergency discharge speed
Solution Approach 2:
The discharge circuit transitions from a static resistance configuration to a dynamic one where the resistance value can change based on operational state. The switchable resistor configuration allows the system to adapt between normal discharge mode and emergency rapid discharge mode, achieving both safety during operation and speed during emergencies
2Speed
If rapid discharging components are added to reduce discharge time to milliseconds, then discharge speed improves, but device complexity and installation space increase
Solution Approach 1:
The existing intermediate circuit components serve dual purposes: during normal operation, they maintain system voltage and supply power; during emergency conditions, the same components enable rapid discharge through the switchable resistor configuration. This eliminates the need for separate dedicated rapid discharge components, reducing overall system complexity
Solution Approach 2:
The patent merges the normal discharge function and emergency rapid discharge function into a single integrated circuit configuration. By combining the existing intermediate circuit with a switchable resistor network controlled by the pyrotechnic switch, the system achieves rapid discharge capability without adding separate complex discharge subsystems
3Reliability
If the high-voltage battery is disconnected in the event of an accident, then safety is improved, but the stored energy in intermediate circuit capacitors remains creating a continuing hazard
Solution Approach 1:
The pyrotechnic switch is pre-configured to simultaneously perform two actions upon activation: disconnect the high-voltage battery from the electrical system AND connect the rapid discharge path for the intermediate circuit capacitors. This preliminary preparation of the discharge path ensures that when the accident occurs, both battery disconnection and energy dissipation happen concurrently, eliminating the continuing hazard of stored energy
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 pyrotechnic switch enables rapid disconnection of the high-voltage battery from the electrical system and targeted discharging of capacitors, reducing the risk to emergency personnel by discharging energy in the millisecond range, significantly shorter than prior art, without increasing costs or installation space.
Implementation Method 1
The pyrotechnic ignition element is arranged in the first conductor region and is configured to generate an increase in pressure in order to disconnect the predetermined disconnection point
Data Source
AI summary
A pyrotechnic switch for switching off and establishing electric circuits includes a first electrical conductor, a second electrical conductor, and an ignition element. In a first state of the pyrotechnic switch, the first electrical conductor and the second electrical conductor are electrically connected to one another, wherein a target separation point between the first electrical conductor and the second electrical conductor is provided. The target separation point is separated as soon as the ignition element is triggered, wherein the pyrotechnic switch is provided with a third electrical conductor. In the first state of the pyrotechnic switch, the third electrical conductor is electrically separated from the second electrical conductor and from the third electrical conductor, and in a second state of the pyrotechnic switch, the third electrical conductor is electrically connected to the second electrical conductor.