Traction Battery Charging Mode Switching for Low-Temperature Protection
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Solution Overview
Problem
Direct current charging in low-temperature environments adversely affects the performance of traction batteries in electric vehicles, leading to reduced efficiency and potential safety risks such as lithium deposition and battery failure.
Innovation Solution
A charging method and system that dynamically adjusts between pulse charging and direct current charging based on battery temperature and voltage, using a battery management system to send mode demand information to the charging pile, enabling pulse charging when temperatures are low and direct current charging when temperatures are normal, without the need for a thermal management system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If direct current charging is used in low-temperature environment, then charging simplicity is maintained, but battery performance deteriorates and safety risks increase
Solution Approach 1:
The charging system dynamically switches between direct current charging mode and pulse charging mode based on battery temperature conditions. When temperature is above the first preset threshold, direct current charging is used; when temperature drops below the threshold, pulse charging mode is activated to prevent battery performance degradation while maintaining charging effectiveness.
Solution Approach 2:
The system changes the charging parameter by switching from constant voltage/current direct charging to pulsed voltage/current charging when temperature drops below the first preset threshold. This parameter change adapts the charging method to low-temperature conditions, preventing lithium deposition and battery failure while maintaining charging efficiency.
2Reliability
If thermal management system is added to heat battery at low temperature, then battery performance is protected, but device complexity and cost increase
Solution Approach 1:
The battery itself serves its heating needs through pulse charging. The pulsed charging current generates heat within the battery through internal resistance, naturally raising the battery temperature to an acceptable range for charging. This eliminates the need for external thermal management systems while protecting battery performance.
Solution Approach 2:
The invention extracts the heating function from a separate thermal management system and integrates it into the charging process itself. By using pulse charging, the heating function is achieved through the charging current, removing the need for dedicated heating devices and simplifying the overall system.
3Reliability
If pulse charging mode is used at low temperature, then battery performance is protected and heating time is reduced, but charging efficiency may be affected
Solution Approach 1:
The system uses periodic pulsed charging instead of continuous direct charging when temperature is below the first preset threshold. The pulsed action allows brief intervals for heat distribution and prevents excessive localized heating, protecting battery performance while maintaining acceptable charging efficiency through optimized pulse parameters.
Solution Approach 2:
The charging system dynamically adapts between charging modes based on real-time temperature monitoring. When temperature rises above the first preset threshold during pulse charging, the system automatically switches to efficient direct current charging mode, maximizing charging efficiency when conditions permit while protecting the battery when temperature is low.
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
Ensures battery performance by preventing degradation at low temperatures, improves charging efficiency, and enhances safety by adapting charging modes, while reducing costs and heating times, thus optimizing the charging process.
Implementation Method 1
Due to the electrochemical characteristics of the traction battery, direct current charging will have a greater impact on the performance of the traction battery in a low-temperature environment
Data Source
AI summary
A charging method is provided, which includes: acquiring a state parameter of a traction battery, the state parameter including a battery temperature; sending first charging mode demand information to a charging pile when the battery temperature is lower than a first preset threshold, where the first charging mode demand information is used for indicating a pulse charging mode, the pulse charging mode is a charging mode using a pulsed voltage or a pulsed current, and the pulsed voltage or the pulsed current is used for charging the traction battery. According to the technical solution of the embodiment of the application, the charging pile can output pulse current to charge the traction battery, so as to prevent the performance of the traction battery from being affected by directly charging the traction battery at a low temperature, thereby ensuring the performance of the traction battery.