Current-Based Battery Balancing in Voltage Conversion Systems
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Solution Overview
Problem
Existing battery unbalance mitigation methods in voltage conversion systems are inefficient, unpredictable, and slow due to their reliance on voltage-based charging control, which is affected by battery characteristics like relaxation time and unknown parameters.
Innovation Solution
A current-based method for detecting and addressing battery unbalance by utilizing the relationships between the voltage conversion system's output current and charging currents to apply different charging currents to each battery, ensuring balanced charging and quick restoration of battery levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If voltage-based charging control is used to mitigate battery unbalance, then the method is simple to implement, but the charging process becomes slow and unpredictable due to battery relaxation time and unknown parameters
Solution Approach 1:
The patent changes the control parameter from voltage-based to current-based charging control. By monitoring and comparing charging currents instead of voltages, the system achieves faster and more predictable battery balancing while maintaining implementation simplicity. The current-based approach directly controls the charging rate, overcoming the slow response inherent in voltage-based methods affected by relaxation time.
2Ease of operation
If voltage-based charging control is used, then the control method is straightforward, but the prediction of charging behavior becomes unreliable due to unknown battery parameters
Solution Approach 1:
The invention switches from voltage monitoring to current monitoring for detecting battery unbalance. By measuring charging currents directly and comparing them between battery strings, the system achieves reliable and predictable detection of unbalance conditions. This current-based parameter provides more direct and accurate information about actual charging status, eliminating the unpredictability caused by voltage-based methods.
3Power
If equalizer circuits are used to provide higher output current, then the current limitation of the converter is overcome, but the system complexity increases
Solution Approach 1:
The patent employs a self-service approach where the system automatically detects battery unbalance conditions and adjusts charging currents without requiring complex external equalizer circuits. By using current sensors and a control unit that monitors charging parameters in real-time, the system self-regulates to provide appropriate charging currents to each battery string, achieving high current capability without additional complex circuitry.
Data Source
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AI summary
An improved battery unbalance mitigation in a voltage conversion system is disclosed.The voltage conversion system includes a first and a second battery being connected in series with each other, and a converter having a converter input and a converter output, wherein the converter input is connected to at least one of the first and the second battery. The voltage conversion system further includes a voltage conversion system output being connected to one of the first and the second battery, and to the converter output, thereby producing a voltage conversion system output current I sys out . According to the present invention, a determination if a charging level unbalance in the voltage conversion system is present is based on the voltage conversion system output current I sys out . If an unbalance is present, a first charging current I b 1 is applied to the first battery and a second charging current I b2 is applied to the second battery, where the first and the second charging current I b 1, I b2 are different from each other.