Fuel Cell Electrolyte Replenishment via Pre-mixed Solution

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Solution Overview

Problem

Existing fuel cell systems face challenges in maintaining the optimal electrical conductivity of electrolytes due to variations in solute concentration caused by secondary phenomena, such as solute transport to storage tanks and poisoning by carbon dioxide, leading to inefficiencies and the need for continuous and unpredictable alkalinity adjustments.

Innovation Solution

A system with an intermediate tank and measurement, pre-mixing, and replenishing means using a densimeter, conductivity meter, or optical sensor to monitor and adjust the solute concentration in the electrolyte, employing a pre-mixed replenishing solution to rapidly restore ideal concentrations, avoiding direct contact with corrosive electrolytes and using a heat exchanger for thermal conditioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If direct replenishment of solute into the electrolyte is used, then the replenishment process is simple, but the speed and accuracy of concentration adjustment is slow and imprecise

Engineering Contradiction:
Improvesimplicity of replenishment processVSAvoidspeed of electrolyte replenishment
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The invention pre-mixes the solute with water in a separate mixing tank before introducing it to the electrolyte. This preliminary preparation of a replenishing solution allows for rapid and accurate concentration adjustment without directly handling solid solute, thereby increasing the speed and precision of electrolyte replenishment while maintaining process simplicity.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If direct contact with corrosive electrolyte is required for measurement and replenishment, then the control system can directly monitor and adjust concentration, but the system requires materials with high chemical resistance and becomes more costly

Engineering Contradiction:
Improveaccuracy of solute concentration monitoringVSAvoidchemical resistance requirements and material costs
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention introduces water as an intermediary substance. The solute is first mixed with water in a separate tank to create a replenishing solution, which is then introduced to the electrolyte. This intermediary approach allows measurement and replenishment operations to be performed on the replenishing solution rather than directly on the corrosive electrolyte, eliminating the need for chemically resistant materials while maintaining measurement accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If continuous monitoring and adjustment of electrolyte alkalinity is performed, then the optimal conductivity can be maintained, but the process becomes complex and costly requiring sophisticated measurement and control systems

Engineering Contradiction:
Improvemaintenance of optimal electrical conductivityVSAvoidcomplexity of measurement and control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses water as an intermediary to simplify the monitoring and control process. By measuring and adjusting the concentration of the replenishing solution (solute + water) before it enters the electrolyte, the system can indirectly control the electrolyte's alkalinity without requiring direct, continuous monitoring of the corrosive electrolyte itself. This reduces the complexity and cost of the measurement and control system while maintaining reliable conductivity optimization.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 significantly enhances the speed and accuracy of electrolyte replenishment, maintaining maximum fuel cell efficiency and reducing chemical aggression, resulting in a simpler and less costly management process with minimal chemical resistance issues.

Implementation Method 1

measuring the concentration of the solute in the electrolyte, in particular by measuring the density, the electrical conductivity or the refractive index of the electrolyte

Methodology Applied
Scientific EffectDensity measurement:

Implementation Method 2

measuring the concentration of the solute in the electrolyte, in particular by measuring the density, the electrical conductivity or the refractive index of the electrolyte

Methodology Applied
Scientific EffectElectrical conductivity measurement:

Implementation Method 3

measuring the concentration of the solute in the electrolyte, in particular by measuring the density, the electrical conductivity or the refractive index of the electrolyte

Methodology Applied
Scientific EffectRefractive index measurement:

Implementation Method 4

employing a pre-mixed replenishing solution to rapidly restore ideal concentrations, avoiding direct contact with corrosive electrolytes and using a heat exchanger for thermal conditioning

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3188296B1Adjustment method of the electrolyte composition for a fuel cell system
Publication Date: 2020.02.12 ELECTRO POWER SYST MFG SRL
  • EP3188296B1 patent drawingFigure 1

AI summary

There is provided a procedure for adjusting the composition of an electrolyte in a system (1) comprising a fuel cell (20), consisting of a solution having water as a solvent and a substance that increases the electrical conductivity thereof as a solute, the system (1) further comprising a reaction chamber (2) which uses the electrolyte, the procedure comprising a step of measuring the concentration of the solute in the electrolyte, a step of replenishing the solute in the electrolyte, functionally connected to the step of measuring the concentration of the solute, consisting of: a pre-mixing in water of the solute in the solid state in a mixing tank separate from the reaction chamber (2), with consequent dissolution of the solute and provision of a replenishing solution, and a subsequent introduction of the replenishment solution into the reaction chamber (2).