Flow Battery Electrochemically Active Zone Volume Design
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Solution Overview
Problem
Flow batteries face challenges in rapidly responding to changes in power demand due to limitations in the availability of electrochemically active species, leading to delays and potential side reactions like carbon corrosion, which can damage components and result in parasitic power losses.
Innovation Solution
The design incorporates an electrochemically active zone with a total open volume calculated based on power, pump time, and electrolyte concentration parameters, using Equation I: V=(S×P×tpump)/(E×F×C), to ensure sufficient active species are available for rapid response to power demands, while avoiding excessive voltage and current that could cause corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the flow battery uses conventional flow fields with fixed volume, then the structure is simple and easy to manufacture, but the response time to power demand changes is delayed due to insufficient availability of electrochemically active species
Solution Approach 1:
The patent applies parameter changes by making the flow field volume a variable parameter rather than a fixed dimension. The total open volume of the electrochemically active zone is calculated using the equation V=(S×P×tpump)/(E×F×C), where variables such as power demand (P), pump time (tpump), and concentration (C) can be adjusted to optimize response time. This allows the system to adapt to different operating conditions and power demand scenarios.
Solution Approach 2:
The patent implements preliminary action by pre-calculating and designing the flow field volume based on anticipated power demand scenarios before operation. The volume is determined in advance using the volume equation, ensuring that sufficient electrochemically active species are available in the flow field to meet sudden power demands without delay. This preparatory design prevents response time delays during actual operation.
2Loss of time
If the pump operates at full flow immediately to meet power demand, then the response time is reduced, but carbon corrosion accelerates due to excessive voltage and current
Solution Approach 1:
The patent applies preliminary action by pre-designing the flow field volume to contain sufficient electrochemically active species before power demand occurs. This ensures that when power is needed, the battery can respond rapidly using the pre-positioned active species without requiring immediate high-speed pumping that would cause excessive voltage and current spikes leading to carbon corrosion.
Solution Approach 2:
The patent converts the potential harm of rapid pumping into a benefit by designing the flow field volume equation to account for pump time (tpump). The equation V=(S×P×tpump)/(E×F×C) allows optimization of the balance between response speed and corrosion prevention by adjusting the volume based on acceptable pump ramp-up times, transforming the corrosion risk into a design parameter for optimal performance.
3Loss of time
If the flow field volume is increased to provide more electrochemically active species, then the response time to power demand changes is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent uses parameter changes to optimize flow field volume based on specific operational requirements rather than using a universally large volume. The equation V=(S×P×tpump)/(E×F×C) allows calculation of the minimum necessary volume for given power demands and concentration levels, avoiding unnecessary manufacturing complexity while ensuring adequate response time. This parameter-based approach enables scalable, application-specific design.
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 reduces the response time to power demand changes, ensuring the flow battery can meet electrical loads without accelerating corrosion, thereby enhancing durability and performance.
Implementation Method 1
first and second pumps configured to selectively move first and second fluid electrolytes between the first and second vessels and the first and second flow fields
Implementation Method 2
The electrochemically active zone has a total open volume configured to receive flow of the respective first and second fluid electrolytes
Implementation Method 3
an electrolyte separator layer arranged there between... The separator prevents the electrolytes from freely and rapidly mixing but permits selected ions to pass through to complete the redox reactions
Implementation Method 4
Flow batteries are designed to convert electrical energy into chemical energy that can be stored and later released when there is demand... drive electrochemically reversible redox reactions
Data Source
AI summary
A flow battery includes a cell that has first and second flow fields spaced apart from each other and an electrolyte separator layer. A supply/storage system is external of the cell and includes first and second vessels fluidly connected with the first and second flow fields, and first and second pumps configured to selectively move first and second fluid electrolytes between the vessels and the first and second flow fields. The flow fields each have an electrochemically active zone that is configured to receive flow of the fluid electrolytes. The electrochemically active zone has a total open volume that is a function of at least one of a power parameter of the flow battery, a time parameter of the pumps and a concentration parameter of the fluid electrolytes.