Flow Battery Voltage-Limiting Device for Corrosion Prevention
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Solution Overview
Problem
Flow batteries are susceptible to corrosion during mode transitions, which affects their performance and useful life, due to potential voltage thresholds that can drive undesired corrosion reactions when transitioning between active and inactive modes.
Innovation Solution
Incorporating a voltage-limiting device in the electric circuit of the flow battery, which can be adjusted to control the electric potential across the electrodes during transitions, using resistors or other impedance controls to prevent corrosion by maintaining a non-zero voltage below the threshold for corrosion reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flow battery transitions between active and inactive modes, then the battery can store and release electrical energy, but voltage thresholds are exceeded that drive corrosion reactions on the electrodes
Solution Approach 1:
A voltage-limiting device is introduced as an intermediary component in the electric circuit between the power source and the flow battery electrodes. This device mediates the voltage transmission by clamping or limiting the voltage to predetermined safe levels, preventing excessive voltage from reaching the electrodes during mode transitions while allowing normal charging and discharging operations to proceed
Solution Approach 2:
The voltage-limiting device dynamically changes the voltage parameter transmitted to the electrodes based on the operational state of the flow battery. During mode transitions when voltage spikes occur, the device alters the voltage parameter to remain below the corrosion threshold. During normal operation, the device allows the voltage to maintain its normal charging/discharging levels, thus adapting the voltage parameter to different operational conditions
2Power
If voltage is not limited during mode transitions, then the flow battery can operate with high power output, but carbon corrosion and oxidation reactions occur on the electrodes
Solution Approach 1:
The voltage-limiting device serves as a protective intermediary that filters out harmful voltage excursions during mode transitions. It allows the flow battery to maintain high power output during normal operation while blocking only the specific harmful voltage spikes that cause carbon corrosion, thus preserving both power capability and electrode integrity
Solution Approach 2:
The voltage-limiting device converts the potentially harmful high voltage condition into a beneficial protective function. By detecting and clamping excessive voltage during mode transitions, it transforms what would be a harmful condition (voltage spikes causing corrosion) into a controlled condition (limited voltage that protects electrodes), effectively using the voltage-limiting mechanism to prevent damage
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 voltage-limiting device effectively reduces corrosion by limiting cell voltages during start-up and shut-down processes, thereby extending the battery's performance and lifespan by preventing carbon corrosion and other oxidation reactions.
Implementation Method 1
limiting a voltage potential across a first electrode and a second electrode of the flow battery during and in response to the transitioning by using a voltage-limiting device arranged in an electric circuit that is electrically coupled with the first electrode and the second electrode
Implementation Method 2
A negative liquid electrolyte is delivered to the negative electrode and a positive liquid electrolyte is delivered to the positive electrode to drive electrochemically reversible redox reactions. Upon charging, the electrical energy supplied causes a chemical reduction reaction in one electrolyte and an oxidation reaction in the other electrolyte
Implementation Method 3
The separator prevents the electrolytes from mixing but permits selected ions to pass through to complete the redox reactions
Data Source
Figure 1~2
Figure 3~4
AI summary
A flow battery includes at least one cell that has a first electrode, a second electrode spaced apart from the first electrode and an electrolyte separator layer that is arranged between the first electrode and the second electrode. A storage portion is fluidly connected with the at least one cell. At least one liquid electrolyte includes an electrochemically active specie and is selectively deliverable to the at least one cell. An electric circuit is coupled with the first electrode and the second electrode. The circuit includes a voltage-limiting device that is configured to limit a voltage potential across the first electrode and the second electrode in response to a transition of the at least one cell from an inactive, shut-down mode with respect to an active, charge/discharge mode.