Fuel Cell Stack Warm-Up Control via Voltage Monitoring

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Solution Overview

Problem

In vehicular fuel cell systems, determining the completion of warm-up at low temperatures is challenging due to uneven temperature distribution, leading to increased time and energy consumption before allowing vehicle operation.

Innovation Solution

A control device that generates predetermined warm-up electric power and uses voltage and current values from the fuel cell stack to determine if the warm-up condition is met, thereby providing run permission when the stack reaches a predetermined condition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a highly accurate temperature sensor is used to determine warm-up completion, then measurement precision is improved, but time and energy consumption during warm-up increase due to the need to consider safety margins with uneven temperature values

Engineering Contradiction:

Improvetemperature measurement precisionVSAvoidwarm-up time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent changes the parameter used for warm-up completion determination from temperature to voltage. By monitoring voltage output of the fuel cell stack, the system can accurately determine warm-up completion without the time-consuming temperature uniformity verification, thus reducing warm-up time while maintaining determination accuracy

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the temperature-based determination mechanism with a voltage-based determination mechanism. Instead of using temperature sensors and analyzing temperature distribution, the system uses voltage measurement which directly reflects the electrochemical activity and temperature state of the fuel cell, eliminating the need for complex temperature field analysis

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a highly accurate temperature sensor is used to determine warm-up completion, then measurement precision is improved, but energy and fuel consumption during warm-up increase

Engineering Contradiction:

Improvetemperature measurement precisionVSAvoidenergy consumption during warm-up

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the parameter used for warm-up completion determination from temperature to voltage. By monitoring voltage output of the fuel cell stack, the system can accurately determine warm-up completion without the energy-consuming extended operation required for temperature uniformity verification, thus reducing energy consumption during warm-up

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If temperature-based warm-up determination is used, then reliability is maintained, but device complexity increases due to multiple temperature sensors and analysis requirements

Engineering Contradiction:

Improvewarm-up determination reliabilityVSAvoidtemperature sensing and analysis system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent substitutes the complex temperature-based determination system with a simpler voltage-based determination system. Instead of using multiple temperature sensors and analyzing temperature distribution uniformity, the system uses a single voltage measurement to determine warm-up completion, significantly reducing device complexity while maintaining reliability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the essential information needed for warm-up determination from the complex temperature field analysis to a single voltage parameter. By taking out the voltage output as the determination criterion, the system eliminates the need for multiple temperature sensors and complex analysis algorithms, simplifying the overall system

Inventive Principle:

Principle #2Taking out (Extraction)

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 minimizes the time and energy required for warm-up completion, improving fuel efficiency and reducing unnecessary energy consumption.

Implementation Method 1

a fuel cell stack to generate electric power at less power than a rated electric power during start-up at a low temperature condition

Methodology Applied

Scientific EffectFuel cell electrochemical reaction: Fuel Cell

Data Source

PatentUS8034497B2Control device of vehicular fuel cell system and related method

Publication Date: 2011.10.11 NISSAN MOTOR CO LTD

AI summary

A control device for a vehicular fuel cell system is provided with a warm-up output control section operative, when a fuel cell system is started up under a low temperature condition and in case that a fuel cell stack of the fuel cell system is warmed up, causing the fuel cell stack to generate electric power to allow predetermined warm-up electric power to be taken out, and a run permission section operative, during a period wherein the warm-up electric power is drawn by the warm-up output control section, to determine whether the fuel cell stack assumes a predetermined warm-up condition on the basis of one of a voltage value and an electric current value of the fuel cell stack. When a determination is made that the fuel cell stack assumes the predetermined warm-up condition, the run permission section provides a vehicle with run permission.