Redox Flow Battery Electrolyte Ratio for Higher Discharge Capacity
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Solution Overview
Problem
Conventional redox flow batteries face challenges in maintaining high energy density and discharge capacity due to equal liquid amounts and state of charge (SOC) settings of positive and negative electrolytes, leading to inefficiencies and potential active material deposition.
Innovation Solution
Differentially setting the liquid amounts of positive and negative electrolytes and optimizing their state of charge (SOC) to exceed zero, within specific ratios, allowing wider ranges of SOC use and enhancing energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If equal liquid amounts of positive and negative electrolytes are used, then the battery structure is simple and easy to operate, but the energy density is reduced and discharge capacity is limited
Solution Approach 1:
The patent applies asymmetry by setting different liquid amounts for positive and negative electrolytes. Specifically, the liquid amount of one electrolyte is set to 1.05-5.0 times that of the other, breaking the conventional equal-volume design. This asymmetric configuration allows the battery to achieve higher energy density by optimizing the ratio of active materials while maintaining operational simplicity through a standardized control method.
2Stability of the object's composition
If equal state of charge (SOC) is maintained in both electrolytes, then the valence balance is stable, but the discharge capacity decreases and active material deposition occurs
Solution Approach 1:
The patent changes the SOC parameter from equal values to different values between positive and negative electrolytes. By setting SOC of one electrolyte to 2-20% and the other to 80-98%, the system achieves both stable valence balance (through the specified liquid amount ratio) and high discharge capacity (by utilizing wider SOC ranges). This prevents active material deposition while maximizing energy utilization.
3Quantity of substance
If the liquid amount ratio of electrolytes is set within 1.05-5.0, then the energy density is improved, but the system complexity increases due to differential electrolyte management
Solution Approach 1:
The patent optimizes the liquid amount ratio parameter within the specific range of 1.05-5.0 times, which improves energy density by allowing unequal distribution of active materials. The complexity is managed through a standardized control method that monitors and adjusts electrolyte volumes and SOC values according to predetermined relationships, transforming a potentially complex asymmetric system into a systematically controlled configuration.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the SOC and liquid amount of electrolytes, and adjusting them according to the predetermined ratio relationships. This feedback mechanism ensures that the asymmetric electrolyte configuration maintains optimal performance while preventing deviations that could lead to active material deposition or valence imbalance, thereby managing system complexity through automated control.
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 results in improved energy density and sustained discharge capacity by optimizing electrolyte usage, reducing internal resistance, and minimizing side reactions.
Implementation Method 1
a positive electrolyte containing a positive electrode active material and a negative electrolyte containing a negative electrode active material
Data Source
AI summary
A redox flow battery includes a positive electrolyte containing a positive electrode active material and a negative electrolyte containing a negative electrode active material. A liquid amount of the positive electrolyte is different from a liquid amount of the negative electrolyte. Of the positive electrolyte and the negative electrolyte, a liquid amount ratio of the electrolyte larger in liquid amount to the electrolyte smaller in liquid amount is not lower than 1.05 and not higher than 5.0. A state of charge of a mixture electrolyte which is a mixture of the positive electrolyte and the negative electrolyte at a ratio equal to the liquid amount ratio is equal to or higher than 2%.