EV On-Board Electrical Layout for Low-Battery Wake-Up Charging
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Solution Overview
Problem
Electric vehicles with low charge levels in both high-voltage and low-voltage storage systems face a deadlock situation due to disconnected switches, leading to power loss and inability to charge, with existing solutions lacking sufficient fault-tolerance.
Innovation Solution
An on-board electrical system with redundant low-voltage power supplies and wake-up electrical lines allows separate power supply to master electronic control units, enabling the system to overcome the deadlock by connecting to an external jump-starter device, thereby initiating charging despite open switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both HV and LV electrical storage systems have low charge levels causing switches to disconnect, then protection from damage is improved, but the vehicle cannot be started or charged creating a deadlock
Solution Approach 1:
The patent introduces a jump-starter device as an intermediary component that temporarily connects to the LV battery through the wake-up electrical lines. This intermediary provides the necessary power to wake up control units and close the protective switches, thereby resolving the deadlock without compromising the protective function. The jump-starter acts as a mediator that bridges the gap between the protected system and the external power source.
2Device complexity
If a single LV power supply is used, then device complexity is reduced, but fault tolerance is insufficient when switches are opened
Solution Approach 1:
The patent segments the LV power supply into two independent power supply units, each with its own control unit and wake-up electrical lines. This segmentation allows one power supply to remain functional even if the other fails or is disconnected, thereby improving fault tolerance. The segmented architecture ensures that critical functions can continue operating with reduced capability rather than complete failure.
3Reliability
If LV switch is opened to protect low charge battery, then battery damage risk is reduced, but power loss occurs to critical components like DC/DC converter and control units
Solution Approach 1:
The patent implements preliminary action by providing wake-up electrical lines that can deliver power to control units before the LV switch is closed. This allows control units to be activated and prepare the system for charging even when the LV switch remains open due to low battery charge. The preliminary power supply enables the system to transition from a protected state to an operational state without compromising battery safety.
Data Source
AI summary
An electrical system for an electric vehicle includes a high-voltage power supply including a high-voltage storage system in series with a high-voltage switch, first and second low-voltage power supplies respectively having first and second low-voltage storage systems in series with first and second switches, a first DC/DC converter connected to the high-voltage power supply and the first low-voltage power supply via a first low-voltage DC bus, a second DC/DC converter connected to the high-voltage power supply and the second low-voltage power supply via a second low-voltage DC bus, first and second master control units respectively connected to the first and second low-voltage DC buses for power supply and controlling operation of the first and second switch, a first wake-up connector arrangement temporarily connectable to a low-voltage jump-starter device, first and second wake-up lines respectively connecting the first wake-up connector arrangement with the first and second low-voltage DC buses.