EV Battery RTC Powered by HV System via Voltage Divider
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Solution Overview
Problem
The existing electric-vehicle battery systems face high power consumption and high production costs due to the use of low-dropout regulators for powering the real-time clock (RTC), especially during idle periods, and there is a need for a more efficient and cost-effective power supply solution.
Innovation Solution
The integration of a real-time clock (RTC) into the battery disconnect unit (BDU) with a high-voltage system, where the RTC is temporarily powered by the high-voltage system during active states and by the low-voltage system during idle states, utilizing a voltage divider to adapt the input voltage for efficient power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low-dropout regulator is used to power the RTC, then the RTC can be continuously powered with stable voltage, but power consumption and production costs increase significantly
Solution Approach 1:
The patent implements dynamic power supply switching for the RTC based on system state. During active operation, the RTC is powered by the LV system through the LDO regulator. During idle periods, the RTC is powered by the HV system directly, bypassing the LDO. This dynamic switching adapts the power supply configuration to system needs, reducing unnecessary power consumption during idle states while maintaining reliable operation during active states.
Solution Approach 2:
The patent employs periodic monitoring of system state (active vs. idle) to switch between different power supply modes for the RTC. The BSM periodically determines whether the vehicle is in idle or active state and accordingly activates either the HV-to-RTC power path or the LV-to-RTC power path through the LDO. This periodic action ensures the RTC receives appropriate power while minimizing energy consumption during extended idle periods.
2Reliability
If a low-dropout regulator is used to power the RTC, then voltage stability is maintained, but production costs increase
Solution Approach 1:
The patent implements dynamic power supply switching for the RTC based on system state. During active operation, the RTC is powered by the LV system through the LDO regulator. During idle periods, the RTC is powered by the HV system directly, bypassing the LDO. This dynamic switching adapts the power supply configuration to system needs, reducing unnecessary power consumption during idle states while maintaining reliable operation during active states.
Solution Approach 2:
The patent extracts the LDO regulator from the continuous power supply path for the RTC. Instead of having the LDO continuously regulate voltage to the RTC, the system extracts the LDO from this continuous service and only engages it when necessary (during active operation). During idle periods, the RTC is powered directly from the HV system without passing through the LDO, thereby eliminating unnecessary cost and complexity associated with continuous LDO operation.
3Reliability
If the RTC is powered during idle periods, then time tracking is maintained, but power consumption increases
Solution Approach 1:
The patent employs periodic monitoring of system state (active vs. idle) to switch between different power supply modes for the RTC. The BSM periodically determines whether the vehicle is in idle or active state and accordingly activates either the HV-to-RTC power path or the LV-to-RTC power path through the LDO. This periodic action ensures the RTC receives appropriate power while minimizing energy consumption during extended idle periods.
Solution Approach 2:
The patent makes the HV system serve multiple functions: it powers the high-voltage loads during active operation and simultaneously serves as a power source for the RTC during idle periods. This multi-functionality eliminates the need for dedicated RTC power supply during idle states, reducing overall power consumption while maintaining time tracking capability.
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 solution reduces power consumption and production costs by ensuring a secure and efficient power supply to the RTC during all operational states, while minimizing power usage during idle periods.
Implementation Method 1
utilizing a voltage divider to adapt the input voltage for efficient power management
Data Source
Figure 1
AI summary
the present disclosure refers to an electric-vehicle battery system comprising: a high voltage system, HV system, with a plurality of connected rechargeable battery cells; a low voltage system, LV system, with an operating voltage lower than an operating voltage of the HV system, wherein the LV system supplies a battery system manager, BSM: a real time clock, RTC, configured for providing a system time to the BSM; and a battery disconnect unit, BDU, comprising BDU relays to switchably open or close an HV line of the HV system and a BDU control unit adapted to control the BDU relays, wherein the BDU is adapted to exchange data with the BSM via a communication interface. The RTC is integrated into the BDU and the BDU is adapted such that the RTC is at least temporarily powered by the HV system.