Pulse Charging Conversion for Low-Temperature EV Batteries
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Solution Overview
Problem
Existing power battery charging methods for electric vehicles are inefficient in low-temperature environments, leading to prolonged charging times and potential battery degradation due to direct current charging, which causes lithium deposition and reduces battery life.
Innovation Solution
A charging system that includes a power conversion apparatus capable of converting direct current power from a charging pile into alternative power types, such as pulsed voltage or current, to charge the power battery in a pulse charging mode when the battery temperature is low, thereby preventing lithium deposition and extending battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct current charging is used in low-temperature environment, then charging speed is improved, but battery performance deteriorates due to lithium deposition
Solution Approach 1:
The patent applies periodic pulsed charging instead of continuous direct current charging. The charging current is applied in pulses with specific duty cycles (e.g., 10%-50%) and frequencies (e.g., 0.1-10 Hz), creating periodic on-off cycles that prevent lithium deposition while maintaining effective charging speed in low-temperature environments.
Solution Approach 2:
The patent changes the charging parameters by converting from direct current to pulsed alternating current with variable frequency and duty cycle. The system adjusts the pulse width modulation (PWM) parameters dynamically based on battery temperature and state of charge, transforming the charging mode to prevent lithium precipitation while maintaining charging efficiency.
2Reliability
If thermal management system is added to heat battery in low temperature, then battery performance is improved, but device complexity increases
Solution Approach 1:
The patent enables the battery to self-heat through the pulsed charging process itself. The intermittent current application causes internal resistance heating within the battery cells, raising the temperature to optimal charging range without requiring external thermal management systems. The battery essentially heats itself through the charging mechanism.
Solution Approach 2:
The patent extracts and eliminates the thermal management system from the charging setup. By using pulsed charging that generates internal heat, the system removes the need for separate heating devices, thermal management controllers, and associated infrastructure, significantly reducing system complexity.
3Reliability
If pulsed charging mode is used in low temperature, then battery performance is protected, but charging time increases
Solution Approach 1:
The patent employs dynamic adjustment of pulsed charging parameters including frequency, duty cycle, and amplitude based on real-time battery temperature and state of charge. The system transitions from static pulsed charging to dynamic adaptive charging, optimizing the pulse characteristics at different charging stages to minimize total charging time while preventing lithium deposition.
Solution Approach 2:
The patent maintains continuous charging action through high-frequency pulsing that appears effectively continuous to the battery chemistry. By using sufficiently high pulse frequencies and appropriate duty cycles, the system maintains continuous ion transport and charging progress without the harmful effects of direct current, reducing overall charging time compared to traditional pulsed methods.
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
The proposed solution enables efficient charging of power batteries in low-temperature environments without the need for a thermal management system, reducing charging time, preventing battery degradation, and improving overall battery performance.
Implementation Method 1
converting direct current power from a charging pile into alternative power types, such as pulsed voltage or current, to charge the power battery in a pulse charging mode
Data Source
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AI summary
An embodiment of the present application discloses a charging method, including: acquiring a state parameter of a power battery by a power conversion apparatus, the state parameter including a battery temperature; setting a charging mode to a pulse charging mode by the power conversion apparatus when the battery temperature is lower than a first preset threshold; and converting charging power of a charging pile and then charging the power battery by the power conversion apparatus in the pulse charging mode, the pulse charging mode being a charging mode outputting a pulsed voltage or a pulsed current. Through the technical solution, the power conversion apparatus acquires a battery temperature of the power battery, when the battery temperature is lower than the first preset threshold, the power conversion apparatus converts the charging power output by the charging pile, and outputs a pulse current to charge the tract battery, to prevent the charging pile directly charging the power battery in a low temperature and impact on the performance of the power battery, thereby ensuring the performance of the power battery.