Lithium-Ion Battery Kinetic Model Fast Charging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional charging methods for lithium-ion batteries, such as constant current-constant voltage and pulse charging, are inefficient and can lead to reduced battery capacity and shorter lifespan due to prolonged charging times and safety concerns like overheating, while existing models primarily simulate discharging processes.
Innovation Solution
A kinetic model is used to derive an optimal current profile for fast charging, consisting of a constant current stage followed by a varying current stage, partitioning battery capacity into diffused and indiffused wells with charge flow regulated by inductance and height differences, effectively mimicking the diffusion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional constant current-constant voltage charging is used, then battery safety is maintained, but charging time is prolonged (up to 3 hours for full charge)
Solution Approach 1:
The patent applies dynamics by transitioning from static charging rates to dynamic adjustment of charging current based on real-time battery state. The system continuously monitors battery parameters and adjusts the charging current profile accordingly, enabling the charger to operate at optimal current levels throughout the charging process rather than using fixed constant current or voltage stages.
Solution Approach 2:
The patent implements feedback mechanisms by continuously measuring battery state parameters (voltage, current, temperature, charge level) and using this information to adjust the charging current. The system incorporates feedback loops that monitor battery response and modify the charging profile in real-time, allowing the charger to adapt to changing battery conditions and optimize charging speed while maintaining safety.
2Loss of time
If pulse charging with high current is used, then charging time is reduced, but lithium ion intercalation is incomplete leading to accumulated reduced lithium at the interface
Solution Approach 1:
The patent applies dynamics by using dynamic current modulation within pulse charging cycles. Rather than using fixed high current pulses, the system adjusts the amplitude and duration of current pulses based on real-time battery state, ensuring that each pulse is optimized to achieve complete lithium intercalation while minimizing charging time. The dynamic adjustment prevents the accumulation of reduced lithium at the interface.
Solution Approach 2:
The patent implements feedback by monitoring battery state during pulse charging and adjusting subsequent pulses accordingly. The system uses feedback from voltage, current, and charge level measurements to modify pulse parameters, ensuring that each pulse achieves complete lithium intercalation. This feedback mechanism prevents the accumulation of reduced lithium by adjusting pulse characteristics based on actual battery response.
3Productivity
If charging current is increased to reduce charging time, then charging speed improves, but battery capacity decreases and battery life shortens
Solution Approach 1:
The patent applies dynamics by using variable charging current that adapts to battery state rather than applying constant high current. The system dynamically adjusts current levels based on real-time measurements of battery charge level, voltage, and temperature, allowing high current only when the battery can safely accept it. This dynamic approach enables fast charging while preventing the degradation associated with sustained high current charging.
Solution Approach 2:
The patent implements feedback by continuously monitoring battery parameters and using this information to adjust charging current levels. The feedback mechanism detects when the battery is approaching saturation or when conditions indicate potential degradation, and automatically reduces current accordingly. This feedback-controlled current adjustment maintains high charging speed when safe while protecting battery lifespan by preventing excessive current when the battery cannot accept it.
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 significantly reduces charging time by maximizing the charging current and regulating the flow between wells, offering a safer and more efficient charging method compared to conventional techniques, with charging times reduced by up to five times the standard hour-long charging current.
Implementation Method 1
partitioning battery capacity into diffused and indiffused wells with charge flow regulated by inductance and height differences, effectively mimicking the diffusion process
Data Source
AI summary
A battery is charged by first charging the battery at a constant current during a first time interval, and then charging the battery at a varying current during a second time interval. The battery can be a lithium-ion battery, and the charging uses a kinetic model. The kinetic model models the battery having an indiffused well having a capacity c, and a diffused well having a capacity 1−c, and the indiffused well is filled directly by the current, and the diffused well is filled only from the indiffused well via a valve with constant inductance.