Dynamic Charging Current Profile for Fast Lithium-Ion Battery Charging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lithium-ion battery charging methods, such as CCCV, result in lengthy charging times due to significantly reduced charging currents during the constant voltage phase, which increases the overall time to fully charge the battery without effectively accelerating battery degradation.
Innovation Solution
A method and system that dynamically apply a charging current to lithium-ion batteries, exceeding the steady-state voltage limit until a cutoff criterion is satisfied, allowing for faster charging while preventing overcharging by updating the cutoff criterion based on the battery's rest voltage and age.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant voltage charging is applied to fully charge the battery, then the battery reaches full capacity, but the charging time becomes excessively long
Solution Approach 1:
The patent applies a dynamic charging current that varies over time rather than a static constant voltage. The current is dynamically adjusted based on the battery's state of charge, applying higher currents when the battery can accept them and reducing current as the battery approaches full charge, thereby optimizing both charging speed and battery safety
Solution Approach 2:
The patent changes the charging parameter from fixed constant voltage to a time-varying current profile. By modifying the current parameter as a function of time and battery state, the system achieves faster charging while maintaining battery health constraints that would be violated by simple constant voltage charging
2Productivity
If high charging current is applied to reduce charging time, then charging speed increases, but battery degradation accelerates
Solution Approach 1:
The patent employs time-varying current parameters that are optimized to balance charging speed and battery health. The current profile is designed to deliver high initial currents for fast charging while progressively reducing current magnitude and duration to stay within safe operational limits that prevent excessive degradation
Solution Approach 2:
The system uses feedback from battery voltage and current measurements to adjust the charging profile in real-time. By monitoring the battery's response to charging current and comparing it against predetermined safety thresholds, the system dynamically adjusts parameters to maximize charging speed while preventing harmful degradation effects
Data Source
AI summary
A method for charging a battery comprises: measuring a battery voltage with a voltage sensor and a battery current with a current sensor; applying, with a charging circuit, a first charging current to the battery until the measured battery voltage exceeds a predetermined voltage threshold, a magnitude of the first charging current being held at a first constant value; applying, with the charging circuit, in response to the measured battery voltage exceeding the predetermined voltage threshold, a second charging current to the battery until a cutoff criterion is satisfied, a magnitude of the second charging current being such that the battery voltage exceeds a steady state voltage limit for the battery; after the cutoff criterion is satisfied, determining a rest voltage of the battery; and updating the cutoff criterion based on a difference between the determined rest voltage and a target rest voltage.