Traction Battery Pulse Charging for Low-Temperature Fast Charging
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Solution Overview
Problem
Direct current charging of lithium-ion batteries in low-temperature environments leads to increased internal resistance, reduced capacity, lithium deposition, and potential safety hazards such as combustion and explosion, while existing thermal management systems prolong charging times and increase weight and cost.
Innovation Solution
A charging system with a power conversion module that converts direct current into pulsed electricity, allowing for intelligent switching between pulse and direct current charging modes based on battery temperature and voltage, eliminating the need for a thermal management system.
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 safety deteriorates due to lithium deposition and internal resistance increase
Solution Approach 1:
The patent applies periodic pulsed charging instead of continuous direct current charging. The charging process uses alternating charging pulses and resting periods, where during charging pulses lithium ions are inserted into the battery, and during resting periods the battery relaxes and temperature equalizes. This periodic action prevents continuous lithium deposition while maintaining acceptable charging speed, resolving the contradiction between charging productivity and battery safety in low-temperature environments.
2Reliability
If thermal management system is added to heat battery, then battery performance is improved, but device weight and cost increase
Solution Approach 1:
The patent employs self-heating through the battery's own internal resistance during pulsed charging. The alternating charging and resting cycles generate heat through Joule heating during charge pulses, and the resting periods allow this internally generated heat to distribute throughout the battery. This self-service heating approach eliminates or reduces the need for external thermal management systems, improving battery performance without significantly increasing system weight.
3Reliability
If thermal management system is added to heat battery, then battery performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs self-heating through the battery's own internal resistance during pulsed charging. The alternating charging and resting cycles generate heat through Joule heating during charge pulses, and the resting periods allow this internally generated heat to distribute throughout the battery. This self-service heating approach eliminates or reduces the need for external thermal management systems, improving battery performance without significantly increasing system weight.
4Reliability
If pulsed charging is used, then battery safety is improved, but charging time increases
Solution Approach 1:
The patent applies periodic pulsed charging instead of continuous direct current charging. The charging process uses alternating charging pulses and resting periods, where during charging pulses lithium ions are inserted into the battery, and during resting periods the battery relaxes and temperature equalizes. This periodic action prevents continuous lithium deposition while maintaining acceptable charging speed, resolving the contradiction between charging productivity and battery safety in low-temperature environments.
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
Improves charging efficiency and safety by preventing performance degradation, reducing charging time, and avoiding lithium deposition without adding weight or cost, ensuring reliable battery performance across temperature variations.
Implementation Method 1
A charging system with a power conversion module that converts direct current into pulsed electricity
Implementation Method 2
Direct current charging will have a greater impact on the performance of the traction battery in a low-temperature environment
Data Source
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AI summary
A charging method is provided, which includes: acquiring a state parameter of a traction battery (121), the state parameter including a battery temperature; sending first charging mode demand information to a charging pile (110) 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 (121). According to the technical solution of the embodiment of the application, the battery management system (122) acquires the battery temperature of the traction battery (121), when the battery temperature is low, for example, when the battery temperature is lower than the first preset threshold, first charging mode demand information indicating a pulse charging mode is sent to the charging pile (110), and in the pulse charging mode, the charging pile (110) can output pulse current to charge the traction battery (121), so as to prevent the performance of the traction battery (121) from being affected by directly charging the traction battery (121) at a low temperature, thereby ensuring the performance of the traction battery (121).