Traction Battery Heating via Bidirectional DC Converter Cycling
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Solution Overview
Problem
Lithium-ion traction batteries in electric vehicles experience reduced discharge capacity and efficiency at low temperatures, leading to impaired performance and safety concerns due to lithium precipitation and dendrite formation, with existing heating methods being inefficient and unable to meet increasing battery capacity demands.
Innovation Solution
A control method and apparatus that utilizes a bidirectional DC converter to form charging and discharging circuits for traction batteries, cyclically charging and discharging them to generate heat and improve temperature uniformity, especially in low-temperature environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional heating methods (air heating, liquid heating, resistance wire heating, heat pipe) are used to heat traction batteries in low-temperature environments, then the battery temperature can be increased, but the heating time is long, energy consumption is high, and temperature uniformity is poor
Solution Approach 1:
The battery uses its own internal resistance to generate heat through cyclic charging and discharging, eliminating the need for external heating devices. The battery heats itself by converting electrical energy to thermal energy through its internal resistance, achieving rapid and uniform temperature increase without long heating times or high energy consumption from external sources
Solution Approach 2:
The method changes the operational parameters of the battery by performing cyclic charging and discharging at controlled current rates. By adjusting the charging and discharging current parameters, the internal heat generation is optimized to achieve rapid heating while maintaining temperature uniformity across the battery cells
2Temperature
If traditional heating methods are used to heat traction batteries, then the battery temperature can be increased, but energy consumption is high
Solution Approach 1:
The battery serves its own heating needs by utilizing its internal resistance to convert electrical energy to thermal energy during cyclic charging and discharging. This eliminates the energy waste associated with external heating systems, as the energy for heating comes directly from the battery's own operational cycles rather than from separate high-consumption heating devices
Solution Approach 2:
The method converts the harmful effect of internal resistance (which causes energy loss and heat generation) into a beneficial heating mechanism. By controlling cyclic charging and discharging, the previously wasted energy through internal resistance is now harnessed to efficiently heat the battery, turning an energy loss into a useful heating source
3Temperature
If traditional heating methods are used to heat traction batteries, then the battery temperature can be increased, but temperature uniformity is poor
Solution Approach 1:
The battery heats itself uniformly through internal resistance distribution during cyclic charging and discharging. Since the heating occurs throughout the entire battery structure simultaneously through its own electrical cycles, temperature uniformity is naturally achieved without the hot spots and uneven heating patterns characteristic of external heating methods
Solution Approach 2:
By controlling the charging and discharging current parameters and cycle frequency, the method optimizes heat distribution throughout the battery. The cyclic parameter changes ensure that heat is generated uniformly across all battery cells, achieving excellent temperature uniformity that external heating methods cannot provide
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 approach efficiently heats traction batteries, enhancing their performance and safety by reducing charging time and improving discharge power, while addressing the limitations of existing heating methods.
Implementation Method 1
cyclically charging and discharging the traction battery through the charging and discharging circuit to heat the traction battery
Data Source
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AI summary
The disclosure relates to the technical field of electric vehicles, and in particular, to a control method and apparatus for a traction battery, a vehicle, a medium, and a device, aiming at solving the problem of how to conveniently and efficiently heat a traction battery, especially a large-capacity traction battery. To this end, the control method for a traction battery according to an embodiment of the disclosure comprises analyzing whether each traction battery needs to be heated on the basis of temperature information of the traction battery, and controlling a bidirectional DC converter and the traction battery which needs to be heated to form a charging and discharging circuit to cyclically charge and discharge the traction battery, so as to achieve the goal of heating the traction battery. By means of the foregoing steps, the characteristic of high internal resistance of a lithium-ion traction battery at a low temperature can be used to make the traction battery generate heat by means of a cyclic charging and discharging process, to achieve the heating of the traction battery, that is, the performance of the traction battery can be improved, the time for charging the traction battery is reduced, and the safety of the traction battery is further improved.