Emergency Disconnect Circuit With Manual Pyro Trigger for HV Battery Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In high-voltage battery electric systems, such as those in electric vehicles, there is a need for a reliable method to ensure complete disconnection of the propulsion battery pack from the high-voltage bus after a threshold impact event, as existing automatic systems may not provide sufficient assurance, especially for first responders and salvage operations.
Innovation Solution
An emergency disconnect circuit is introduced, which includes a manual switch in series with a pyrotechnic switch and a low-voltage power supply, allowing for manual triggering of the pyrotechnic switch to disconnect the high-voltage battery pack from the bus, providing an additional layer of control and assurance that the disconnection has occurred.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an automatic electronic monitoring unit with pyrotechnic switch is used for disconnection, then the disconnection speed is fast, but the reliability of ensuring complete disconnection is insufficient
Solution Approach 1:
The disconnection system is segmented into two independent parts: an automatic electronic monitoring unit with pyrotechnic switch for fast disconnection, and a manual switch with separate power supply for verification and backup. This segmentation allows each part to specialize in its function while together they achieve both speed and reliability.
Solution Approach 2:
A manual switch with independent low-voltage power supply is prepared in advance as a backup mechanism. This manual override is readied beforehand to compensate for potential failures of the automatic system, ensuring that disconnection can still be achieved even if the electronic monitoring unit fails.
2Device complexity
If only an automatic electronic monitoring unit is used, then the device complexity is low, but the ease of operation for manual verification is poor
Solution Approach 1:
A manual switch serves as an intermediary mechanism between the operator and the pyrotechnic switch. This manual interface allows first responders to directly control and verify disconnection without needing to understand or interact with the complex electronic monitoring circuitry, simplifying the operator's task while maintaining system integrity.
3Reliability
If a manual switch with separate power supply is added, then the reliability of disconnection is improved, but the device complexity increases
Solution Approach 1:
The manual switch and its power supply are extracted as a separate, independent subsystem from the automatic electronic monitoring unit. This extraction allows the manual verification system to be added without modifying or complicating the existing automatic system, maintaining its simplicity while adding reliability through the independent manual path.
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 emergency disconnect circuit ensures reliable and manual disconnection of the high-voltage battery pack from the bus, even if the electronic monitoring unit fails to trigger the pyrotechnic switch, thereby enhancing safety for first responders and salvage operations by providing a direct mechanism to verify and enforce disconnection.
Implementation Method 1
a pyrotechnic switch configured to open in response to an electronic triggering signal to thereby disconnect the high-voltage battery pack from the high-voltage bus
Implementation Method 2
A transition of the manual switch from an open position to a closed position connects the low-voltage power supply to the pyrotechnic switch, and thereby causes the low-voltage power supply to discharge the electronic triggering signal to the pyrotechnic switch
Data Source
AI summary
An emergency disconnect circuit for use with a high-voltage (HV) bus of a battery electric system, e.g., aboard a mobile system, includes a pyrotechnic switch and a manual switch. The pyrotechnic switch configured irreversibly opens in response to an electronic triggering signal to disconnect an HV battery pack from the HV bus in a first manner. The manual switch is arranged on a low-voltage (LV) bus in series with and between the pyrotechnic switch and an LV power supply. Transition of the manual switch from an open position to a closed position connects the LV power supply to the pyrotechnic switch. This causes the LV power supply to discharge the triggering signal to the pyrotechnic switch. When used aboard a mobile system, an electronic monitoring unit generates the triggering signal in a second manner in response to a threshold impact event.