Fuel Cell Maximum Power Calculation During Intermittent Operation

Solution Overview

Problem

Fuel cell systems face errors in calculating maximum power due to variations in current-voltage characteristics during intermittent operations, leading to reduced power generation efficiency.

Innovation Solution

A fuel cell system with measurement, output characteristic updating, maximum power calculation, and determination means to assess and update output characteristics, allowing for accurate maximum power calculation using the updated characteristics before transitioning to intermittent or low-power situations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the I-V characteristic value is updated periodically to reduce error caused by variation, then the accuracy of maximum power calculation is improved, but during intermittent operation the power generation state is lowered and the I-V characteristic value becomes temporarily lowered, leading to reduced maximum power calculation accuracy when normal operation resumes

Engineering Contradiction:

ImproveI-V characteristic value accuracyVSAvoidmaximum power calculation reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary action by detecting intermittent operation states in advance and preventing I-V characteristic value updates during these states. The determination unit identifies when the fuel cell is in intermittent operation (such as during idle, low-speed travel, or regenerative braking) before the update occurs, thereby preventing the temporary lowering of the I-V characteristic value that would otherwise occur during these transient states.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring the operation state of the fuel cell and using this information to control the update timing of the I-V characteristic value. The determination unit provides feedback about the operation state (normal vs. intermittent) to the control mechanism, which then adjusts whether updates should proceed, ensuring that updates only occur when the fuel cell is in a stable normal operation state.

Inventive Principle:

Principle #23Feedback

2Measurement precision

If the I-V characteristic value is updated during intermittent operation, then the measurement precision is improved for current conditions, but the maximum power calculation becomes inaccurate because the I-V characteristic value reflects the temporarily lowered state rather than the true capability

Engineering Contradiction:

Improveoutput characteristic measurement precisionVSAvoidmaximum power calculation accuracy

Core Design Contradiction:

Measurement precisionVSPower

Solution Approach 1:

The system performs preliminary action by detecting intermittent operation states in advance and preventing I-V characteristic value updates during these states. The determination unit identifies when the fuel cell is in intermittent operation (such as during idle, low-speed travel, or regenerative braking) before the update occurs, thereby preventing the temporary lowering of the I-V characteristic value that would otherwise occur during these transient states.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring the operation state of the fuel cell and using this information to control the update timing of the I-V characteristic value. The determination unit provides feedback about the operation state (normal vs. intermittent) to the control mechanism, which then adjusts whether updates should proceed, ensuring that updates only occur when the fuel cell is in a stable normal operation state.

Inventive Principle:

Principle #23Feedback

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 errors in calculating maximum power available at the fuel cell, ensuring efficient power generation even during intermittent operations by using the most recent updated output characteristics.

Implementation Method 1

hydrogen gas as fuel gas is supplied on an anode side of the fuel cell to generate power by the electrochemical reaction of air and hydrogen gas

Methodology Applied

Scientific EffectElectrochemical reaction:

Data Source

PatentUS9991535B2Fuel cell system and maximum power calculation method

Publication Date: 2018.06.05 TOYOTA JIDOSHA KK

AI summary

The fuel cell system includes: a fuel cell 40 that receives supply of reactant gas to generate power; output characteristic updating means for updating an output characteristic of the fuel cell 40 based on output current and output voltage measured by a current sensor 140 and a voltage sensor 150; maximum power calculation means for calculating, using the output characteristic, the maximum power available at the fuel cell 40; and determination means for determining whether a value of the output characteristic is in an assumed situation where the output characteristic value is assumed to be temporarily lowered, wherein while the output characteristic value is determined by the determination means to be in the assumed situation, the maximum power calculation means calculates the maximum power using the output characteristic updated by the output characteristic updating means just before transition to the assumed situation.