Power Conversion Control for Low-Temperature Battery Charging
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Solution Overview
Problem
In low temperature environments, direct current charging of lithium batteries in hybrid electrical vehicles can lead to lithium plating, limiting charging capacity and increasing charging time, posing challenges for power supply in traditional lithium battery packs.
Innovation Solution
A power conversion apparatus is introduced between the charging pile and the power battery, equipped with a control unit and power unit to detect and convert power types, including voltage and current changes, ensuring safe and efficient charging by prioritizing power sources such as auxiliary power, charging power, or power battery based on state parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct current charging is applied to lithium batteries in low temperature environments, then charging speed is improved, but lithium plating occurs causing safety risks and limiting charging capacity
Solution Approach 1:
The patent introduces a power conversion apparatus as an intermediary device between the DC charging pile and the battery. This apparatus converts the direct current from the charging pile into alternating current, which is then supplied to the battery through the vehicle's existing AC charging infrastructure. This intermediary conversion allows the battery to be charged in AC mode even when a DC charging pile is available, avoiding lithium plating in low temperature conditions while maintaining fast charging capability through the power conversion process
Solution Approach 2:
The patent changes the electrical parameters of the charging current by converting from direct current to alternating current. The power conversion apparatus adjusts the current type, voltage, and frequency parameters to match the battery's charging requirements in low temperature environments. This parameter transformation enables the battery to accept charging power without causing lithium plating, thus resolving the contradiction between charging speed and safety
2Adaptability or versatility
If power conversion apparatus is introduced to enable AC charging from DC charging pile, then charging safety and adaptability are improved, but device complexity increases
Solution Approach 1:
The power conversion apparatus is designed with multi-functionality to handle multiple power supply scenarios. It can accept power from both DC charging piles and vehicle power batteries, convert the power type appropriately, and supply it to the battery through AC charging interfaces. The apparatus also includes intelligent control functions to determine power supply priority based on battery state parameters, making it a universal solution that handles various charging situations without requiring separate systems for different power sources
Solution Approach 2:
The system implements self-service through automatic power supply priority determination. The control unit continuously monitors battery state parameters such as state of charge and temperature, and automatically decides which power source to use and in what priority order. This eliminates the need for manual intervention or complex external control systems, allowing the power conversion apparatus to manage its own operation and adapt to different charging scenarios autonomously
3Productivity
If multiple power sources are prioritized based on state parameters, then charging efficiency and battery protection are improved, but control complexity increases
Solution Approach 1:
The system performs preliminary action by pre-establishing power supply priority rules based on battery state parameters before charging begins. The control unit is programmed with predetermined thresholds and priority sequences for different power sources under various battery conditions. When charging starts, the system automatically applies these pre-set rules to determine power source priority, eliminating the need for complex real-time decision-making algorithms and simplifying the control process while maintaining high charging efficiency
Data Source
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AI summary
Embodiments of the present application provide a power supply control method for a power conversion apparatus and a power conversion apparatus, where the power conversion apparatus is configured to conduct a power conversion between a charging pile and a power battery, the method includes: conducting a power-on self-test with the charging pile of auxiliary power by the power conversion apparatus; determining a power supply priority order of the charging power and the power battery on the basis of a state parameter of the power battery under the condition that the self-test of the power conversion apparatus succeeds; determining the one of the charging power of the charging pile and the power battery with a higher power supply priority as a current working power of the power conversion apparatus by the power conversion apparatus. The method and the apparatus of embodiments of the present application can provide a stable working power for the power conversion apparatus without additional power supply device, thereby effectively solving the power supply problem of the power conversion apparatus.