Pulsed Battery Module Charging With Preheating for Faster EV Recharge
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Solution Overview
Problem
Conventional charging methods for electrical energy storage systems, such as battery packs in electric vehicles, suffer from thermal losses, degradation, and slow charge rates, leading to lengthy charge times and reduced battery lifespan, limiting the widespread adoption of electric vehicles.
Innovation Solution
The implementation of a fast charging system that involves preheating the energy source to lower its impedance, using charge pulses that exceed the double sheet capacitance frequency, and combining pulse preheating or pulse charging with constant current charging at higher temperatures, while monitoring for degradatory conditions like uneven lithiation and lithium plating, to enable higher charge rates without degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional constant current charging method is used, then charging simplicity is maintained, but charge time becomes excessively long
Solution Approach 1:
The patent applies periodic pulsed charging instead of continuous constant current charging. The charging process uses alternating charge pulses and rest periods, where during charge pulses current is applied at high rates and during rest periods the charging is suspended. This periodic action enables faster charging by allowing electrochemical reactions to proceed more efficiently during pulses while preventing degradation during rest periods, thereby reducing overall charge time without requiring overly complex continuous control systems.
Solution Approach 2:
The patent implements a preheating phase before the main charging process. During this preliminary action, heating elements or internal resistance heating is used to raise the battery temperature to an optimal range (e.g., 20-40°C) before applying high-rate charge pulses. This preliminary temperature increase reduces internal resistance and improves ion transport, enabling subsequent fast charging to proceed more efficiently and reduce overall charge time.
2Productivity
If higher voltage charging is used to reduce charge time, then charge speed increases, but battery lifetime is dramatically reduced
Solution Approach 1:
The patent uses periodic pulsed charging where high-rate charge pulses are alternated with rest periods. During the charge pulses, high current rates (e.g., 3C-6C) are applied to achieve fast charging, but during the subsequent rest periods, no current is applied allowing the battery to relax and redistribute ions. This periodic modulation enables sustained high charge rates without the continuous stress that would otherwise cause lithium plating and electrode degradation, thereby maintaining battery lifetime while achieving high productivity.
Solution Approach 2:
The patent converts the typically harmful effect of heat into a beneficial tool. By intentionally heating the battery during a preheating phase or using controlled thermal management, the battery temperature is raised to optimize electrochemical reactions. This controlled heating reduces internal resistance and improves ion transport kinetics, enabling faster charging rates without causing uncontrolled thermal runaway or excessive heat-related degradation, thus converting potential harm into benefit for both charge rate and reliability.
3Loss of time
If fast charging is implemented, then charge time is reduced, but thermal losses and degradation increase
Solution Approach 1:
The patent employs periodic pulsed charging where high-rate charge pulses are followed by rest periods. During the charge pulses, fast charging occurs reducing charge time, but the subsequent rest periods allow thermal management systems to dissipate accumulated heat and prevent thermal runaway. The periodic interruption also allows electrochemical reactions to complete and ions to redistribute, preventing concentration gradients and lithium plating. This periodic action thus enables fast charging while actively managing thermal losses and minimizing degradation.
Solution Approach 2:
The patent implements monitoring of battery temperature, voltage, and current during charging. This feedback information is used to dynamically adjust charging parameters - reducing pulse duration or increasing rest periods when temperature rises, or adjusting pulse amplitude based on state of charge estimates. The feedback control system detects early signs of degradation such as voltage anomalies or temperature spikes and modifies the charging profile accordingly, enabling fast charging while minimizing thermal losses and degradation through real-time adaptation.
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 allows for rapid charging of energy storage systems, reducing charge time and minimizing degradation, thereby enhancing the usability and longevity of electric vehicle batteries.
Implementation Method 1
heating an energy source through application of a preheating signal that raises the source temperature
Implementation Method 2
charging an energy source with charge pulses at a frequency that passes a double sheet capacitance of the energy source and reduces an activation impedance of the source
Data Source
AI summary
Embodiments that provide advanced charging of energy source arrangements for energy storage applications are disclosed. The embodiments can be used within energy storage systems having a cascaded arrangement of converter modules. The embodiments can include the application of pulses to an energy source of each module of the system. The pulses can be applied for charging and preheating purposes. Control techniques can be used to distribute charge signals from a charge source to multiple modules of an energy storage system.