Redox Flow Battery Electrolyte Mixing for Capacity Rebalancing
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Solution Overview
Problem
Redox flow battery systems face capacity degradation due to electrolyte imbalances and side reactions, leading to reduced lifespan and increased complexity and cost with existing methods that require additional tanks and chemicals.
Innovation Solution
A method involving circulating positive and negative electrolytes between respective compartments using existing storage chambers, with a cleansing cycle initiated when capacity falls below a threshold, mixing the electrolytes to rebalance the state of charge and reduce capacity loss, without additional tanks or chemicals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional tanks and chemicals are added to manage electrolyte imbalance, then electrolyte rebalancing capability is improved, but system complexity and cost increase
Solution Approach 1:
The patent combines the positive and negative electrolyte storage chambers into a single integrated tank structure, eliminating the need for separate tanks and external rebalancing equipment. The mixing valve system enables direct electrolyte mixing between compartments within the same tank, simplifying the overall system architecture while maintaining electrolyte management capability.
Solution Approach 2:
The system performs self-rebalancing by mixing electrolytes internally through the mixing valve mechanism when imbalance is detected. This eliminates the need for external subsystems or additional chemicals to manage electrolyte states, as the battery system handles its own electrolyte management autonomously.
2Reliability
If additional tanks and chemicals are added to manage electrolyte imbalance, then electrolyte rebalancing capability is improved, but system cost increases
Solution Approach 1:
The patent combines the positive and negative electrolyte storage chambers into a single integrated tank structure, eliminating the need for separate tanks and external rebalancing equipment. The mixing valve system enables direct electrolyte mixing between compartments within the same tank, simplifying the overall system architecture while maintaining electrolyte management capability.
Solution Approach 2:
The system performs self-rebalancing by mixing electrolytes internally through the mixing valve mechanism when imbalance is detected. This eliminates the need for external subsystems or additional chemicals to manage electrolyte states, simplifying manufacturing and reducing system cost.
3Ease of operation
If conventional battery operation continues without cleansing cycle, then operational simplicity is maintained, but capacity degradation increases
Solution Approach 1:
The patent implements a periodic cleansing cycle that activates when the battery reaches full charge state. During this cycle, the mixing valve opens to allow electrolyte mixing between positive and negative compartments, resetting the electrolyte balance. This periodic intervention maintains capacity retention without requiring complex continuous monitoring or control systems.
4Reliability
If electrolyte mixing is performed frequently to maintain capacity, then capacity retention is improved, but operational complexity increases
Solution Approach 1:
The patent uses a controller that monitors battery charge state and triggers the mixing valve based on feedback from the battery's electrochemical state. When the battery reaches full charge or detects electrolyte imbalance, the controller activates the mixing valve to perform cleansing. This feedback-based control maintains capacity retention while avoiding unnecessary mixing operations that would increase 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 maintains electrolyte health and extends the number of cycles before capacity loss, reducing system complexity and cost while maintaining performance, as demonstrated by the ability to operate redox flow batteries for over 10,000 cycles with minimal capacity degradation.
Implementation Method 1
circulating a positive electrolyte between a positive electrode compartment and a positive electrolyte chamber with a positive electrolyte pump
Implementation Method 2
circulating a negative electrolyte between a negative electrode compartment and a negative electrolyte chamber with a negative electrolyte pump
Implementation Method 3
performing a battery cleansing cycle, including mixing the positive electrolyte with the negative electrolyte until a redox flow battery state of charge (SOC) is less than a threshold SOC
Data Source
AI summary
A method of cleansing a redox flow battery system may include operating the redox flow battery system in a charge, discharge, or idle mode, and responsive to a redox flow battery capacity being less than a threshold battery capacity, mixing the positive electrolyte with the negative electrolyte. In this way, battery capacity degradation following cyclic charging and discharging of the redox flow battery system can be substantially reduced.