Flow Battery SOC Estimation Using Negative Electrode Plating
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Solution Overview
Problem
Existing methods for determining the state of charge (SOC) of oxidation-reduction flow batteries are not accurate due to offsetting side reactions at the negative electrode, which affects the overall battery storage capacity and charging/discharging efficiency.
Innovation Solution
The method involves adjusting the operation of the battery using a controller based on the plating efficiency of the negative electrode and current flow, which helps in estimating the SOC by considering side reactions and improving the accuracy of SOC estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ORP measurement of positive electrolyte is used to estimate SOC, then the measurement is simple, but the accuracy is insufficient due to negative electrode side reactions offsetting the overall battery storage capacity
Solution Approach 1:
The patent segments the SOC estimation process into two independent parts: positive electrode ORP measurement and negative electrode plating efficiency measurement. By measuring these separately and combining the results, the system captures both electrode contributions to overall battery capacity, resolving the inaccuracy caused by relying solely on positive electrolyte ORP while maintaining operational simplicity through modular measurement approach
Solution Approach 2:
The patent merges ORP measurement with plating efficiency measurement to create a comprehensive SOC estimation system. The controller combines data from both measurement methods, integrating the simplicity of ORP sensing with the accuracy of plating efficiency tracking, thereby achieving both ease of operation and measurement precision
2Measurement precision
If plating efficiency and current flow measurements are used to determine SOC, then the accuracy of SOC estimation is improved, but the device complexity and control requirements increase
Solution Approach 1:
The patent implements feedback control where the controller continuously monitors plating efficiency measurements and current flow data, then uses this feedback to adjust SOC estimation in real-time. The system incorporates feedback loops that compare measured values with expected values and make corrections, improving accuracy while managing control complexity through systematic feedback mechanisms
Solution Approach 2:
The system uses the battery's own operational data (current flow and plating efficiency) to self-determine its SOC state without requiring external complex measurement equipment. The controller leverages existing sensor data and computational resources already present in the battery management system, achieving high accuracy without proportionally increasing device complexity
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 enhances the accuracy of SOC estimation for oxidation-reduction flow batteries, improves control over the battery, and determines when a cleansing procedure is necessary to maintain efficiency.
Implementation Method 1
plating efficiency of the negative electrode may be indicative of a battery's capacity to source and sink current and the plating efficiency values may relate to side reactions at the negative electrode
Implementation Method 2
The oxidation-reduction flow battery stores electrical energy in chemical form in electrolyte and it also converts chemical energy into electrical energy via redox reactions that include the electrolyte
Data Source
AI summary
Systems and methods for operating an electric energy storage device are described. The systems and methods may generate a state of charge estimate that is based on negative electrode plating. An overall state of charge may be determined from the state of charge estimate that is based on negative electrode plating and a state of charge estimate that is not based on negative electrode plating.