High-Voltage Disconnection Device with Segmented Switching Units
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Solution Overview
Problem
Existing high-voltage on-board power systems in motor vehicles face challenges in reliably disconnecting high-voltage lines, particularly due to long switch-off times in low overcurrent scenarios and inability to disconnect in events independent of overcurrent, such as accidents.
Innovation Solution
A disconnection device with two actuatable switch-off units and an overcurrent protection apparatus, where a control unit activates the units independently of current strength to ensure rapid and reliable disconnection of high-voltage lines, utilizing pyrotechnic switches for fast and irreversible disconnection, and an overcurrent protection apparatus designed for high disconnection capacity with low carrying capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only an overcurrent protection apparatus (fuse) is used to disconnect the high-voltage line, then the device complexity is low, but the switch-off time is very long in low overcurrent scenarios and the system cannot disconnect in events independent of overcurrent
Solution Approach 1:
The disconnection device is segmented into two independent disconnection units: a first disconnection unit with a first switch-off unit for independent disconnection capability, and a second disconnection unit with a second switch-off unit and overcurrent protection apparatus for overcurrent-specific disconnection. This segmentation allows each unit to be optimized for its specific function while maintaining overall system reliability.
Solution Approach 2:
The control unit is designed to activate the first switch-off unit in advance for events independent of overcurrent (such as accidents), before any potential harm occurs. This preliminary action ensures that the high-voltage line is disconnected proactively in critical situations where overcurrent may not be present, thereby improving disconnection reliability.
2Reliability
If a fuse is used with high current carrying capacity to handle all scenarios, then the device can handle both overcurrent and non-overcurrent events, but the cost and weight increase significantly
Solution Approach 1:
The overcurrent protection function is segmented from the main disconnection apparatus. The overcurrent protection apparatus is designed with low current carrying capacity since it only needs to handle overcurrent scenarios, not the full operating current. The first switch-off unit handles the main disconnection for non-overcurrent events, allowing the overcurrent protection apparatus to be lighter and less expensive.
Solution Approach 2:
The overcurrent protection apparatus is designed to perform only the partial function of protecting against overcurrent, rather than being oversized to handle all possible scenarios. This partial action approach allows for a lighter, more cost-effective design while maintaining reliability through the complementary first disconnection unit.
3Reliability
If the overcurrent protection apparatus is designed for high current carrying capacity, then it can handle all operating conditions, but the cost increases
Solution Approach 1:
The disconnection system is segmented into two functional paths: one for normal operation (first disconnection unit) and one for overcurrent protection (second disconnection unit with overcurrent protection apparatus). This segmentation allows the overcurrent protection apparatus to be manufactured with lower specifications (lower current carrying capacity) while maintaining overall system reliability.
Solution Approach 2:
The first switch-off unit serves as a universal disconnection mechanism that can handle both normal operation disconnection and emergency disconnection scenarios. This multi-functionality allows the overcurrent protection apparatus to be specialized and optimized for its specific overcurrent protection function, reducing manufacturing costs.
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
Enables quick and reliable disconnection of high-voltage lines in both overcurrent and critical events, ensuring line protection and safety by using a less expensive and lighter overcurrent protection apparatus, and includes a discharge unit for rapid energy dissipation in accidents.
Implementation Method 1
utilizing pyrotechnic switches for fast and irreversible disconnection
Implementation Method 2
fuses that are able to interrupt a circuit by melting a fuse element when a current strength of the current exceeds a particular threshold value over a predetermined duration
Data Source
AI summary
A disconnection device for a high-voltage electrical system of a motor vehicle for disconnecting a high-voltage line of the high-voltage electrical system, includes an overcurrent protection apparatus; a first disconnecting unit which is made of a first actuatable disconnecting unit, the first disconnecting unit being designed to interrupt a current flow over the first disconnecting unit in the activated state; a second disconnecting unit which is made of a second actuatable disconnecting unit and the overcurrent protection apparatus, the second disconnecting unit being designed to conduct an overcurrent to the overcurrent protection apparatus which interrupts the current flow over the second disconnecting unit in the activated state; and a control unit which is designed to activate at least the second disconnecting unit in the event of an overcurrent and to activate at least the first disconnecting unit in the event of an overcurrent-independent event in order to separate the high-voltage line.