Vanadium Electrolyte Valence Restoration via Electrolysis

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Solution Overview

Problem

Vanadium redox flow batteries face irreversible capacity loss due to increased valence of the electrolyte, which cannot be sustainably restored through existing methods, leading to system failure and environmental contamination from residual additives.

Innovation Solution

A method involving electrolysis with separation, using oxalic acid as a reducing agent at the positive electrode of an electrolysis device, to accurately restore the valence of the vanadium electrolyte without chemical interference, combined with a self-adjusting mixture restoration mechanism to balance electrolyte concentrations and valences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chemical reducing agents are used to restore electrolyte valence, then capacity restoration is achieved, but residual additives interfere with electrolyte composition and performance

Engineering Contradiction:

Improvecapacity restorationVSAvoidresidual additive interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces chemical reduction methods with an electrochemical electrolysis system. The electrolysis device uses electrical energy to drive the reduction reaction at the cathode, converting V5+ to V4+ without requiring chemical reducing agents. This substitution eliminates residual additive interference while achieving the same capacity restoration effect.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an electrolysis device as an intermediary system between the degraded electrolyte and the desired restored state. The device includes electrodes and a power supply that mediate the valence restoration process through controlled electrolysis, avoiding direct contact with chemical reducing agents and thus preventing contamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If self-balancing mechanism is used to restore electrolyte, then temporary capacity recovery is achieved, but valence continues to rise and balance is gradually lost

Engineering Contradiction:

Improvetemporary capacity recoveryVSAvoidelectrolyte life

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent employs the battery's own electrolysis device and power supply to perform the restoration, making the system self-sufficient. The electrolysis unit uses electrical energy (which can be from the battery itself or external source) to restore the electrolyte valence without requiring external chemical agents, enabling sustained operation over the battery's lifetime.

Inventive Principle:

Principle #25Self-service

3Object-affected harmful factors

If electrolysis method is used to restore electrolyte valence, then capacity is restored without chemical residues, but system complexity increases

Engineering Contradiction:

Improvechemical residue eliminationVSAvoidelectrolysis system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent designs the electrolysis device to serve multiple functions: it acts as both a restoration unit for degraded electrolyte and a potential power generation unit. The same electrodes and electrolyte system can function in both modes, reducing the need for separate dedicated restoration equipment and thereby limiting the increase in system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 method effectively and sustainably restores the electrolyte's valence and capacity, reducing capacity decay and maintaining system performance, while avoiding toxic substances and by-products, thus extending the life of the battery and ensuring environmental safety.

Implementation Method 1

the positive electrode electrolyte is electrolyzed and then transferred to the negative electrode through an electrolysis device

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Implementation Method 2

using oxalic acid as a reducing agent at the positive electrode of an electrolysis device, to accurately restore the valence of the vanadium electrolyte

Methodology Applied

Scientific EffectRedox Reactions: Redox Reactions

Data Source

PatentUS11251452B2Method of restoring electrolyte of vanadium redox flow battery through electrolysis

Publication Date: 2022.02.15 ATOMIC ENERGY COUNCIL INSTITUTE OF NUCLEAR ENERGY RESEARCH

AI summary

A method is provided for restoring an electrolyte of vanadium (V) redox flow battery (VRFB). Electrolyte data of an original system are analyzed in advance. A reusable positive electrode is further equipped with a V electrolyte. A reductant for a stack of VRFB is used in coordination as an electrolysis device. After a long-term reaction with a VRFB having a high valence (greater than 3.5), an electrolyte at the positive electrode is directed out to a negative electrode of the electrolysis device; and, then, electrolysis is processed after accurate calculation. In the end, the internal fluid balancing method of the original system is combined. Thus, a harmless and quick valence restoration is processed for the electrolyte of the original system, which is a final resort for the restoration of V electrolyte.