BMS-Guided CC-CV Battery Charging for Cell Balance and Overcharge Prevention
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Solution Overview
Problem
Current lithium-ion battery charging methods are inefficient, leading to prolonged charging times and potential overcharging, which can damage batteries and increase the risk of explosion, while existing strategies fail to balance state of charge across individual cells effectively.
Innovation Solution
A charging system and method that utilizes a battery management system (BMS) to monitor and actively control the state of charge (SOC) of individual cells, transitioning from constant current to constant voltage charging based on a pre-determined SOC value, thereby reducing charging time and ensuring safe and balanced charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant current charging is used to reduce charging time, then charging speed is improved, but the risk of overcharging and battery damage increases
Solution Approach 1:
The charging system dynamically switches between constant current and constant voltage charging modes based on real-time battery state monitoring. The BMS continuously tracks SOC and automatically transitions from CC mode to CV mode when the battery approaches full charge, optimizing both charging speed and safety without manual intervention.
Solution Approach 2:
The battery management system implements continuous feedback monitoring of battery state of charge, voltage, and current parameters. This feedback loop enables the system to detect when the battery reaches optimal charge levels and automatically adjusts charging parameters or terminates charging to prevent overcharging, ensuring battery safety while maximizing charging efficiency.
2Reliability
If traditional charging methods are used, then battery safety is maintained, but charging time is excessively long
Solution Approach 1:
The system performs preliminary monitoring and assessment of battery state before initiating charging. The BMS pre-evaluates battery conditions, determines optimal charging parameters, and prepares the charging profile in advance, enabling faster charging while maintaining safety protocols from the outset rather than reacting to battery state during charging.
Solution Approach 2:
The charging system dynamically changes electrical parameters (current and voltage) based on real-time battery state of charge. It transitions from high-current constant current mode for rapid charging to constant voltage mode as the battery approaches full charge, optimizing the balance between charging speed and battery safety through continuous parameter adjustment.
3Ease of operation
If voltage-based charging control is used, then charging simplicity is maintained, but accuracy in determining state of charge is insufficient
Solution Approach 1:
The system replaces simple voltage-based control with an intelligent battery management system that uses advanced algorithms and multiple sensing parameters. The BMS substitutes basic voltage measurement with comprehensive state estimation incorporating current, voltage, temperature, and charge history data, achieving high SOC accuracy while maintaining automated operation.
Solution Approach 2:
The charging control system combines multiple measurement approaches and algorithms (voltage, current integration, temperature compensation, and SOC estimation algorithms) into a composite control strategy. This multi-parameter composite approach achieves precise state of charge determination while maintaining ease of operation through automated integrated control.
Data Source
AI summary
A charging system for a vehicle includes a charger in electronic communication with at least one control unit; and a battery management system (BMS). The charger is configured to supply constant energy in constant current mode to at least one battery for a pre-determined duration until a state-of-charge (SOC) of the at least one battery is less than a pre-determined battery state of charge (BSOC). The BMS is configured to determine a charging mode of the charger and the at least one control unit is configured to monitor the SOC continuously. The charger is configured to supply energy in the constant voltage mode (CV) when the SOC of the at least one battery is more than the pre-determined BSOC and the charger is configured to stop charging when the SOC is equal to full charge capacity of the at least one battery.