Adaptive Battery Balancing Thresholds for Series Cell Voltage Control
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Solution Overview
Problem
Conventional battery balancing control methods rely on constant voltage thresholds, which can lead to severe imbalances due to incomplete charging and discharging cycles, misjudging battery voltage, and varying internal resistance, resulting in prolonged and energy-intensive recovery processes.
Innovation Solution
A battery balancing system and method that uses a voltage sensing unit, characteristic voltage selector, and control unit to adaptively adjust threshold voltages based on sensed battery voltages, executing charge removal or supply commands to maintain balance, with the characteristic voltage being correlated with the lowest or highest voltage signals, or an average, to ensure balanced charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant voltage threshold is used for battery balancing control, then the control method is simple to implement, but the balancing effect deteriorates due to incomplete charging and discharging cycles causing severe voltage imbalance
Solution Approach 1:
The patent transforms the static constant voltage threshold into a dynamic adaptive threshold that automatically adjusts based on the actual battery voltage and charging state. The control unit continuously monitors battery voltage and modifies the threshold voltage accordingly, enabling the system to adapt to varying battery conditions and maintain effective balancing throughout the charging process.
Solution Approach 2:
The patent changes the threshold voltage parameter from a fixed constant to a variable that dynamically adjusts based on battery state. By modifying the threshold voltage according to actual battery voltage and charging current, the system achieves better balancing effectiveness without sacrificing operational simplicity.
2Measurement precision
If the constant voltage threshold is set close to the margin of battery operation voltage range, then the control method can detect voltage differences, but batteries are incompletely charged and discharged resulting in severe imbalance
Solution Approach 1:
The adaptive threshold voltage dynamically adjusts its value based on the actual battery voltage and charging state, allowing the system to maintain effective voltage difference detection across the entire charging range without being constrained to a fixed threshold near the voltage range margin.
Solution Approach 2:
The control unit continuously monitors the actual battery voltage and uses this feedback to adjust the threshold voltage accordingly. This closed-loop feedback mechanism ensures that the threshold remains appropriate for the current charging state, enabling both accurate voltage difference detection and complete charging cycles.
3Ease of operation
If battery voltage is used as the reference for balancing control, then the control method is easy to implement, but the actual battery voltage is misjudged due to varying internal resistance and charging current
Solution Approach 1:
The system dynamically adjusts the threshold voltage based on the relationship between battery voltage, internal resistance, and charging current. This adaptive approach compensates for voltage misjudgment caused by varying internal resistance, maintaining accurate balancing control while keeping the implementation relatively simple.
Solution Approach 2:
The patent modifies the threshold voltage parameter to account for variations in internal resistance and charging current. By changing the threshold dynamically rather than using a fixed reference, the system achieves more accurate battery state assessment without significantly increasing implementation complexity.
4Duration of action of moving object
If conventional balancing control is executed based on misjudged battery voltage, then the control process continues, but the imbalance worsens and requires much longer time and more energy to recover
Solution Approach 1:
The control unit continuously monitors battery voltage and adjusts the threshold voltage based on feedback from the actual battery state. This prevents execution of balancing control based on misjudged voltage, avoiding worsening imbalance and reducing the time and energy required for recovery.
Solution Approach 2:
The system uses its own monitoring capabilities to detect and correct potential misjudgment issues before they lead to severe imbalance. By self-correcting based on continuous voltage monitoring and adaptive threshold adjustment, the system prevents energy-wasting recovery scenarios.
Data Source
AI summary
A battery balancing system includes a voltage sensing unit, a characteristic voltage selector and a control unit. The voltage sensing unit senses a battery voltage of each of the batteries connected in series in a battery group and generates corresponding battery voltage sensing signals. The characteristic voltage selector generates a characteristic voltage according to the battery voltage sensing signals. The control unit compares the characteristic voltage with a threshold voltage in a balance operation mode, to adaptively adjust the threshold voltage, and compares the battery voltage sensing signal with the adjusted threshold voltage to generate a battery balancing command, thereby executing a charge removal balancing command or a charge supplying balancing command on the corresponding battery, or thereby cease executing the charge removal balancing command or cease executing the charge supplying balancing command on the corresponding battery.