Dual-Battery SOC Control for EV Load Power Source Switching
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Solution Overview
Problem
Current electric vehicle battery systems face risks of over-discharge due to the competitive power supply mode, which does not account for the actual statuses of high-voltage and low-voltage batteries, leading to potential damage and reduced service life.
Innovation Solution
A method and device for charging and discharging battery systems that involve real-time detection of State of Charge (SOC) values and power requirements to control charge-and-discharge processes, ensuring that the high-voltage and low-voltage batteries are utilized efficiently and safely, with the option to switch power sources based on load demands and battery statuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If competitive power supply mode is used to supply power to low-voltage loads, then power supply flexibility is improved, but battery reliability deteriorates due to over-discharge risk
Solution Approach 1:
The control device continuously monitors the SOC values of both high-voltage and low-voltage batteries, and adjusts the power supply strategy in real-time based on the feedback from battery statuses. When the low-voltage battery SOC is sufficient, it supplies power independently; when SOC is low, the system switches to high-voltage battery power supply or combined power supply mode, preventing over-discharge and protecting battery reliability while maintaining power supply flexibility.
2Power
If high-voltage battery is used to power low-voltage loads, then power supply capability is improved, but energy loss increases due to voltage conversion
Solution Approach 1:
The system dynamically adjusts the power supply configuration based on real-time battery SOC values and load requirements. When the low-voltage battery has sufficient charge, it operates independently to avoid energy conversion losses. When the low-voltage battery SOC is low, the system dynamically switches to high-voltage battery power supply or combined power supply mode, optimizing the balance between power supply capability and energy efficiency.
3Use of energy by moving object
If low-voltage battery is used to power loads, then energy efficiency is improved, but power availability deteriorates when battery SOC is low
Solution Approach 1:
The control device performs preliminary assessment of the low-voltage battery SOC before determining the power supply strategy. When the SOC is sufficient, the system pre-configures the low-voltage battery as the independent power source to maximize energy efficiency. When SOC is low, the system pre-switches to high-voltage battery power supply or combined power supply mode, ensuring continuous power availability and preventing power interruption.
Data Source
AI summary
The present application provides a method and a device for charging and discharging a battery system, the battery system and an electric vehicle. The battery system includes a low-voltage battery and a high-voltage battery, the high-voltage battery and the low-voltage battery are both configured to be connected with a load. The method for charging and discharging the battery system includes steps of obtaining a first power of the load when the load is in operation; obtaining a first SOC value of the low-voltage battery and a second SOC value of the high-voltage battery; and controlling charge-and-discharge processes of the high-voltage battery and the low-voltage battery according to the first power, the first SOC value and the second SOC value.