Flow Battery Reference Cell With Wicking Barrier for Stable SoC Sensing
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Solution Overview
Problem
There is a need for a robust and inexpensive method and device to independently measure or detect the state of charge of each electrolyte in a redox flow battery, as existing methods are either impractical or prone to errors due to instrument drift, contamination, and high equipment costs.
Innovation Solution
A state of charge or state of health indicator arrangement for a redox flow battery system, comprising a reference cell and an auxiliary reference electrolyte arrangement with a discrete reservoir, a means for measuring potential difference, and an ionic pathway conduit with a wicking means to maintain ionic connection and inhibit fluid diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional reference electrodes are used to measure state of charge, then measurement can be performed, but the electrodes are subject to contamination and voltage drift after extended periods of immersion
Solution Approach 1:
The invention extracts the reference electrode from direct contact with the test electrolyte by introducing a liquid membrane barrier. The reference electrode remains isolated in a reference compartment while still providing voltage measurements through the membrane, eliminating contamination and drift issues caused by direct immersion in the test electrolyte.
Solution Approach 2:
A liquid membrane acts as an intermediary between the reference electrode and the test electrolyte. This membrane allows ionic conduction for voltage measurement while preventing direct contact between the reference electrode and the test electrolyte, thus blocking contamination pathways and maintaining measurement stability over extended periods.
2Measurement precision
If optical absorption, density and viscosity measurements are used to determine state of charge, then state of charge can be measured, but optical measurements are subject to instrument drift and density/viscosity measurements require expensive equipment
Solution Approach 1:
The invention replaces complex optical and density/viscosity measurement systems with a simple electrochemical voltage measurement approach. By using a reference electrode and liquid membrane to directly measure the potential difference corresponding to state of charge, the system eliminates the need for expensive optical instruments and precision density/viscosity measurement equipment.
3Measurement precision
If in-line density and viscosity measurements are performed with high resolution, then accurate state of charge data can be obtained, but expensive equipment is required especially in harsh chemical conditions
Solution Approach 1:
The invention substitutes complex in-line density and viscosity measurement systems with a simple electrochemical cell that measures voltage potential. This replacement dramatically reduces device complexity while maintaining measurement accuracy, as voltage measurement requires only basic electrochemical components rather than sophisticated optical or mechanical sensors capable of withstanding harsh chemical 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 solution provides a cost-effective and robust method for accurately measuring the state of charge of electrolytes in redox flow batteries, reducing errors associated with instrument drift and contamination, and enabling timely corrective actions to maintain battery health and efficiency.
Implementation Method 1
an ionic pathway conduit with a wicking means to maintain ionic connection and inhibit fluid diffusion
Implementation Method 2
a means for measuring potential difference between a positive electrolyte of or from the positive electrolyte tank of a flow battery and a negative electrolyte of or from the negative electrolyte tank of a flow battery
Data Source
AI summary
A state of charge indicator arrangement for a redox flow battery system having a reference cell arrangement for measuring potential difference between positive electrolyte and negative electrolytes and an auxiliary reference electrolyte arrangement comprising a discrete auxiliary electrolyte reservoir for housing a redox electrode in association with a reference electrolyte, a means of measuring the potential difference between the auxiliary reference electrolyte and the electrolyte of the reference cell arrangement and an ionic pathway conduit linking the auxiliary reference electrolyte reservoir with the electrolyte of the reference cell arrangement, which is configured for low fluid diffusion rate, wherein the conduit comprises a wicking means for absorbing electrolyte and maintaining ionic connection between the auxiliary reference electrolyte reservoir and the respective electrolyte of the reference cell arrangement.