Battery Module Balance Control for Uneven RESS Power Demand
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Solution Overview
Problem
Existing rechargeable energy storage systems (RESS) face operational differences and imbalances between battery modules, which can lead to uneven wear and degradation, particularly under high power demands and long-term use.
Innovation Solution
Implementing a balance control strategy that adjusts power flow between power sources in RESS by setting current and voltage limits based on state of charge (SOC), state of health (SOH), and state of energy (SOE) targets, using DC-DC converters to manage power transfer and minimize operational differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a balance control strategy is implemented to normalize power module operations, then operational imbalances between battery modules are reduced, but system complexity increases due to additional control mechanisms and monitoring requirements
Solution Approach 1:
The balance control strategy continuously monitors the state of charge, voltage, and current of each power module and adjusts power distribution accordingly. The controller receives feedback from voltage sensors and current sensors on each module and dynamically modifies switching signals to equalize operational parameters across all modules, thereby reducing imbalances while managing complexity through automated closed-loop control.
Solution Approach 2:
The system dynamically adjusts operating parameters such as current thresholds, voltage limits, and power distribution ratios for each power module based on their individual states. By changing these parameters in real-time according to module conditions, the system achieves operational normalization without requiring fundamental structural modifications, thus managing complexity through parameter optimization rather than hardware complexity.
2Reliability
If individual power modules are monitored and controlled separately with individual current thresholds, then operational differences between modules are minimized, but measurement and control difficulty increases
Solution Approach 1:
The controller is designed as a universal multi-functional unit that can monitor and control multiple power modules simultaneously using the same control algorithm and sensor interface. Rather than requiring dedicated control circuits for each module, the single controller handles voltage measurement, current threshold determination, switching control, and balance optimization for all modules, thereby reducing measurement and control difficulty through functional consolidation.
Solution Approach 2:
The system uses standardized voltage and current parameters that can be applied universally across different power modules. By expressing module states in terms of common parameters (voltage, current, state of charge percentages) rather than module-specific characteristics, the monitoring and control process becomes more manageable and less complex, as the same measurement and control procedures apply to all modules.
3Duration of action of stationary object
If maximum current thresholds are set for each power module to balance operations, then module lifespan is extended through reduced stress, but power output capability is reduced
Solution Approach 1:
The maximum current thresholds for each power module are not fixed but dynamically adjusted based on real-time module conditions such as state of charge, temperature, and individual health status. When modules are in optimal condition, higher current thresholds are permitted to maximize power output. When modules show signs of stress or degradation, thresholds are reduced to protect lifespan. This dynamic adaptation allows the system to achieve both extended lifespan and maintained power capability at different operating conditions.
Solution Approach 2:
The balance control strategy permits some power modules to operate above their individual maximum current thresholds when the overall system power demand exceeds the balanced capacity. In such cases, the controller allows selective modules to provide excessive current output temporarily to meet peak demands, while other modules operate within their balanced thresholds. This partial relaxation of limits enables the system to maintain both lifespan protection under normal conditions and adequate power capability under peak load conditions.
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
The balance control strategy effectively normalizes power module operations, reducing imbalances and extending the lifespan of power conversion systems by optimizing power distribution and usage according to individual module states.
Implementation Method 1
using DC-DC converters to manage power transfer
Data Source
AI summary
Balance control for a rechargeable energy storage system (RESS) having a plurality of power modules. The balance control may include determining a state deviation for each of the power modules and implementing a balance control strategy to individually control power transfer capabilities of the power modules for purposes of driving the state deviation associated therewith toward a state target.