Battery Charging Top-Off Current Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery charging techniques fail to efficiently manage the increase in battery impedance as it approaches full charge, leading to potential voltage rises that can cause swelling, and do not adapt to changing battery conditions over time.
Innovation Solution
The method involves determining the battery's capacity and state of charge during charging, reducing the charging current as the battery approaches full capacity, and using charging termination parameters such as minimum current cut-off values based on previous charging session duration and charge amount to maintain efficient charging while avoiding voltage increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If charging current is maintained at high levels throughout the charging session, then charging speed is improved, but battery impedance increases and voltage rises causing potential swelling
Solution Approach 1:
The charging current is dynamically adjusted based on real-time monitoring of battery state of charge and impedance changes. The system transitions from constant current charging to variable current charging, reducing current levels as the battery approaches full charge to prevent voltage rise and swelling while maintaining efficient charging during earlier stages.
Solution Approach 2:
The system continuously monitors battery parameters including state of charge, impedance, and voltage during charging. This feedback information is used to automatically adjust the charging current profile, reducing current when the battery nears full charge to prevent harmful voltage increases while maintaining optimal charging speed during earlier stages.
2Object-affected harmful factors
If charging current is reduced during top-off period, then battery swelling is prevented, but charging time increases
Solution Approach 1:
The system performs preliminary high-current charging during the majority of the charging session to rapidly replenish battery capacity. Only during the final top-off period when the battery approaches full charge does the system reduce current, thereby minimizing the time spent at lower charging rates while still preventing swelling.
Solution Approach 2:
The system applies excessive charging current during the main charging phase to maximize charging speed, accepting that this may slightly extend the top-off period. The high current is applied partially (during most of the charging session) rather than continuously, with reduction only when necessary to prevent swelling.
3Device complexity
If charging termination parameter is fixed, then charging control is simplified, but changing battery impedance over time cannot be accounted for
Solution Approach 1:
The charging termination parameter is transformed from a fixed value to a dynamic threshold that adapts based on real-time battery impedance measurements. The system monitors impedance changes throughout charging and adjusts the termination criterion accordingly, allowing simple control logic to handle complex, time-varying battery characteristics.
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 ensures the battery is fully charged without excessive voltage, accounts for changing impedance over time, and maintains a target charging time, thereby preventing battery swelling and ensuring reliable operation.
Implementation Method 1
charging a battery during a top-off period, which typically occurs during an end period of a charging session
Implementation Method 2
During charging, an impedance of the battery may increase as the battery reaches full charge
Data Source
AI summary
This disclosure describes techniques for a method of charging a battery. In an example, the method includes determining a capacity of the battery, and determining a state of charge of the battery. The method also includes charging the battery with a charging current, wherein the charging current is based on the capacity of the battery and the state of charge of the battery, and wherein charging the battery comprises reducing the charging current in response to the state of charge of the battery changing with respect to the capacity of the battery.