High Voltage Network Deactivation via Bus Trigger Signals
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Solution Overview
Problem
Current methods for deactivating high-voltage networks in motor vehicles during diagnosis and repair are costly, space-consuming, and prone to inadvertent reactivation, posing safety hazards due to complex and inaccessible 'service disconnect' components.
Innovation Solution
A method using an external test device to send trigger signals via the motor vehicle's bus system to deactivate and reactivate the high-voltage network, ensuring safe operation through operator-controlled actions, including password entry, without the need for complex 'service disconnect' components, and utilizing existing control units to manage the deactivation and reactivation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a service disconnect component is integrated into the high-voltage battery to deactivate the high-voltage grid, then the high-voltage network can be deactivated during maintenance, but the component increases cost, installation space requirements, and accessibility difficulties
Solution Approach 1:
The invention extracts the deactivation function from a dedicated service disconnect component integrated into the high-voltage battery and relocates it to an external test device. This eliminates the need for expensive, space-consuming hardware within the vehicle and transfers the deactivation capability to a portable diagnostic tool, thereby reducing vehicle complexity and installation space requirements while maintaining safety functionality.
Solution Approach 2:
The test device is designed to perform multiple functions including deactivation of the high-voltage grid, diagnosis, and repair operations. By making the test device universal and multi-functional, the invention eliminates the need for a dedicated service disconnect component, reducing overall system complexity and cost while maintaining the ability to safely deactivate the high-voltage network during maintenance.
2Reliability
If the high-voltage battery is disconnected by hard-cutting lines using a service disconnect, then the high-voltage grid is deactivated, but the method requires precise timing to avoid voltage spikes and damage
Solution Approach 1:
The invention applies preliminary action by de-energizing the high-voltage battery through controlled disconnection of power supply before performing the actual line cutting or maintenance work. The test device initiates a controlled deactivation sequence that prepares the system by removing power in advance, thereby eliminating the risk of voltage spikes and damage during subsequent maintenance operations without requiring precise timing during the critical disconnection moment.
Solution Approach 2:
The invention replaces the mechanical hard-cutting method with an electronic control system. Instead of physically cutting lines under voltage, the test device uses electronic commands to control contactors and switches that open the circuit in a controlled manner. This substitution of mechanical cutting with electronic control eliminates the need for precise timing and manual intervention during high-voltage disconnection, thereby improving safety and reliability.
3Ease of operation
If control units are powered from the low-voltage network and trigger failsafe states when power is interrupted, then device disconnection is automatic, but the high-voltage network cannot be reliably deactivated for maintenance work
Solution Approach 1:
The invention introduces an intermediary test device that communicates with the vehicle's control units via the bus system. This test device acts as a mediator to send specific trigger signals that instruct control units to deactivate the high-voltage network in a controlled manner suitable for maintenance. The intermediary device bridges the gap between the low-voltage control system and the high-voltage power system, enabling reliable deactivation without relying on unintended failsafe states.
Solution Approach 2:
The invention changes the operational parameters of the control units by sending specific trigger signals through the bus system that alter their state from normal operation to maintenance mode. These parameter changes include switching contactors open, disabling charging functions, and preventing reactivation, thereby transforming the system state to enable safe maintenance work rather than relying on power interruption failsafe states.
4Quantity of substance
If multiple high-voltage batteries are present in the vehicle, then energy capacity is increased, but multiple service disconnect components are required increasing cost and complexity
Solution Approach 1:
The test device is designed as a universal multi-functional tool that can deactivate multiple high-voltage batteries through a single interface. Instead of requiring separate service disconnect components for each battery, the test device communicates with the vehicle's central control system via the bus system and sends coordinated deactivation commands to all batteries simultaneously or individually, thereby maintaining high energy capacity while reducing component complexity and cost.
Solution Approach 2:
The invention merges the deactivation function for multiple high-voltage batteries into a single integrated test device interface. Rather than having separate service disconnect components distributed throughout the vehicle for each battery, all deactivation control functions are combined in one portable test device that can manage multiple batteries through centralized control, thereby reducing overall system complexity and component count.
Data Source
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AI summary
The invention relates to a method for the safe deactivation of a high voltage network (3) of a motor vehicle (1) during a diagnosis and/or repair procedure. According to said method, a first operating action is carried out on operating elements of the motor vehicle (1) and/or an external testing device (22) connected to a bus system (20) of the motor vehicle (1), thereby transmitting a first trigger signal to the bus system (20) of the motor vehicle (1). When at least one control appliance (14-19) of the motor vehicle (1) receives the trigger signal, the high-voltage network (3) is deactivated such that it can only be reactivated by a second trigger signal generated by a defined second operating action.