Connector-Based High-Voltage Lockout for EV Powertrains
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Solution Overview
Problem
Existing electrified vehicle powertrain systems rely on manual service disconnects (MSD) and high-voltage interlock (HVIL) monitoring processes to reduce high-voltage exposure, which are application-specific, cumbersome, and require pre-programmed control logic, limiting performance and increasing packaging space and mass.
Innovation Solution
A high-voltage system lockout (HVSL) topology using a battery disconnect unit (BDU) with high-voltage switch devices controlled by a low-voltage drive circuit, where the binary switching state is determined by the energized state of the switch devices, and a multi-piece electrical connector forms a low-voltage switch to create an open-circuit condition, automatically disconnecting the RESS from the high-voltage bus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual service disconnect (MSD) and high-voltage interlock (HVIL) monitoring processes are used to reduce high-voltage exposure, then safety is improved, but device complexity and packaging space increase
Solution Approach 1:
The patent extracts the safety function from complex MSD and HVIL systems by implementing a simple connector-based solution. The connector automatically opens high-voltage circuitry when removed, eliminating the need for separate MSD devices and HVIL monitoring processes while maintaining safety.
Solution Approach 2:
The connector performs self-service safety functions by automatically detecting its own removal and opening the high-voltage circuitry through its internal switch device. This eliminates the need for external monitoring systems to detect service conditions and trigger safety mechanisms.
2Reliability
If manual service disconnect (MSD) and high-voltage interlock (HVIL) monitoring processes are used to reduce high-voltage exposure, then safety is improved, but packaging space and mass increase
Solution Approach 1:
The patent merges the safety disconnect function directly into the electrical connector itself, combining what were previously separate components (MSD device, HVIL monitoring system, and connector) into a single integrated unit. This eliminates the need for additional packaging space for separate safety devices.
Solution Approach 2:
The connector serves multiple functions: it provides electrical connection, enables service access control, and implements high-voltage safety isolation. This multi-functionality eliminates the need for dedicated MSD and HVIL components, reducing overall packaging space.
3Reliability
If pre-programmed HVIL control logic is used to monitor high-voltage bus access, then safety is improved, but device complexity increases
Solution Approach 1:
The patent replaces software-based HVIL control logic with a purely mechanical/electrical solution. The connector's physical removal automatically opens the high-voltage circuitry through its internal switch device, eliminating the need for software monitoring and control logic while maintaining safety.
4Device complexity
If connector-based high-voltage system lockout (HVSL) topology is used to eliminate MSD and HVIL, then device complexity is reduced, but automation extent must be increased
Solution Approach 1:
The connector performs automatic safety isolation through self-service mechanisms. When the connector is removed or disconnected, its internal switch device automatically opens the high-voltage circuitry without requiring external control signals or automated monitoring systems.
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
This approach simplifies and robustifies the electrical system by eliminating the need for MSD and HVIL, reducing reliance on manual processes, minimizing packaging space, and ensuring safe high-voltage isolation through automatic disconnection and reconnection procedures.
Implementation Method 1
A low-voltage drive current is conducted to the high-voltage switch devices via a low-voltage drive circuit to energize the switch devices. The energized switch devices close in response to the low-voltage drive current, with the closed state electrically connecting the RESS to the high-voltage bus
Implementation Method 2
The high-voltage switch devices of the BDU automatically open in response to an open-circuit condition of the drive circuit, such that the low-voltage drive current is physically broken or interrupted. When the high-voltage switch devices are embodied as solenoid-driven devices, absent a generated solenoid field the contactors are unable to remain in the closed state, and consequently spring open when the solenoid field decays.
Data Source
AI summary
An electrical system includes a high-voltage bus connected to a rechargeable energy storage system (RESS) and a high-voltage component connected to the RESS via the voltage bus. The component defines a service opening spanned by a removable cover. The electrical system may include a fastener connecting the cover to the component, as well as a battery disconnect unit (BDU) having a high-voltage switch device connecting the RESS to the high-voltage bus. The switch device closes responsive to a low-voltage drive current to connect the RESS to the high-voltage bus. A drive circuit conducts the current to the switch device. An electrical connector has multiple connector pieces collectively forming a switch in the drive circuit. Disconnection of the pieces from each other opens the switch to interrupt the drive current and cause the high-voltage switch device to open, which disconnects the RESS from the high-voltage bus.