Battery Charging Current Staging for Low-Temperature Fast Charging
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Solution Overview
Problem
Traction batteries face challenges in low-temperature environments, where charge performance is poor, leading to longer charge times.
Innovation Solution
A charge method that uses a higher first charge current to heat the battery until a preset temperature and state of charge threshold is reached, then switches to a lower second charge current for efficient charging, with the first charge current being a pulse current and the second a direct current, to balance heating and energy utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a high charge current is used to charge the battery in low-temperature environment, then the heating effect is enhanced and charge time is reduced, but the risk of lithium precipitation increases
Solution Approach 1:
The charging process is divided into multiple stages: a first charging stage using high current to heat the battery quickly, followed by a second charging stage using reduced current to avoid lithium precipitation. This segmentation allows the system to achieve rapid heating while subsequently preventing harmful effects
Solution Approach 2:
The charge current is dynamically adjusted based on real-time battery temperature and state of charge. The system transitions from high current to reduced current as charging progresses, optimizing both heating efficiency and safety throughout the charging process
2Reliability
If a low charge current is used to charge the battery in low-temperature environment, then the risk of lithium precipitation is reduced, but the heating effect is insufficient and charge time increases
Solution Approach 1:
The system applies high charge current in advance during the first charging stage to rapidly heat the battery to a safe operating temperature, enabling subsequent charging stages to proceed with higher currents without causing lithium precipitation
3Temperature
If pulse current is used for charging, then the heating effect is improved, but the energy utilization decreases
Solution Approach 1:
Pulse current is applied partially during the first charging stage to achieve rapid heating, but the duty cycle is controlled to limit energy waste. The system uses excessive heating action only when necessary to reach the target temperature, then transitions to more efficient charging modes
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 method shortens the overall charge time by quickly heating the battery and ensuring safe charging, reducing the risk of lithium precipitation and improving energy utilization.
Implementation Method 1
the first charge current is used for heating the battery during charging
Implementation Method 2
heat produced by polarization of its cell can be effectively used to increase the temperature of the battery
Data Source
AI summary
A charge method includes obtaining a temperature of a battery, and in response to the temperature of the battery being lower than a preset temperature threshold, determining to use a first charge current to charge the battery until the battery meets a preset condition, and then determining to use a second charge current to charge the battery. The first charge current is used for heating the battery during charging, and the first charge current is greater than the second charge current.