Electric Vehicle Power Supply System Voltage Switching
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Solution Overview
Problem
Existing electric power supply systems in electrical vehicles face challenges in maintaining the operation of the battery ECU when the low-voltage battery's voltage suddenly drops or its power supply is interrupted, leading to potential system failures due to hybrid control unit shutdown and difficulties in normal operation of charging voltage generators and relay switches.
Innovation Solution
An electric power supply system that includes a control electric power supply management device capable of automatically switching between the high-voltage and low-voltage battery power sources based on voltage differences, ensuring continuous operation of the battery ECU by drawing current from the appropriate power line, thereby preventing battery ECU shutdown even during low-voltage battery degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the control system receives electric power only from the low-voltage battery, then the system structure is simple, but the battery ECU may shut down when the low-voltage battery's remaining electric power is reduced
Solution Approach 1:
The low-voltage power supply line is designed to serve dual purposes: normally supplying the control system, and alternatively supplying the battery ECU when the low-voltage battery's electric power is insufficient. This multi-functionality allows the same power supply line to adapt to different operational conditions, ensuring the battery ECU can operate continuously regardless of the low-voltage battery's state.
Solution Approach 2:
The low-voltage power supply line acts as an intermediary between the low-voltage battery and the battery ECU. When the low-voltage battery cannot provide sufficient power, this intermediary line enables alternative power routing, allowing the battery ECU to receive power from the high-voltage battery through the same low-voltage supply line, thus maintaining operational reliability.
2Reliability
If the battery ECU shuts down when low-voltage battery power is depleted, then the system operates reliably under normal conditions, but the high-voltage battery cannot be managed when the low-voltage battery's power supply performance degrades
Solution Approach 1:
The power supply configuration is made dynamic rather than static. The low-voltage power supply line's function changes based on the low-voltage battery's state: under normal conditions it supplies the control system, but when the battery's electric power is insufficient, it dynamically switches to supplying the battery ECU. This dynamic adaptability ensures the battery ECU can continue operating under varying power supply conditions.
Solution Approach 2:
The system utilizes parameter changes in the low-voltage battery's electric power state to trigger functional changes in the power supply architecture. When the battery's remaining electric power falls below a certain threshold, the parameter change activates an alternative power routing mode, allowing the battery ECU to receive power from the high-voltage battery through the low-voltage supply line, thus maintaining adaptability to power supply degradation.
3Loss of energy
If a converter is used for emergency charging from high-voltage to low-voltage battery, then the low-voltage battery can be recharged, but the hybrid control unit and relay switches cannot operate normally due to voltage drop
Solution Approach 1:
The invention extracts the battery ECU's power supply requirement from the exclusive low-voltage battery dependency. By enabling the battery ECU to receive power from the high-voltage battery through the low-voltage power supply line when needed, it separates the battery ECU's power source from the low-voltage battery's state, allowing the battery ECU to continue managing the high-voltage battery even when the low-voltage battery is depleted, thus avoiding the operational failures experienced in conventional systems.
Data Source
AI summary
An electric power supply system of an electrical vehicle includes a first battery, a battery controller managing the first battery, a second battery supplying second power having a voltage lower than a voltage of the first power, and a control electric power supply management device including a joining line that is able to draw a current from each of a first and a second power supply lines. The control electric power supply management device transmits, depending on a magnitude in voltage level between first and second voltages, one of the first and second powers to the battery controller from one of the first and second power supply lines via the joining line. The first and second voltages are respectively applied to the joining line from the first and second power supply lines when the currents are to be drawn from the first and second power supply lines, respectively.