Fuel Cell Output Range Control Using Battery Discharge Modes

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Solution Overview

Problem

Fuel cell systems face rapid deterioration when generating low power, limiting their output range, necessitating a method to expand this range while minimizing degradation.

Innovation Solution

A control method and system that switches between operation modes, utilizing a fuel cell and a battery to output power, where the fuel cell generates power when demand is high and the battery takes over when demand is low, with a mode switching unit to adjust based on target power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the fuel cell operates at low power to meet small power demands, then the system can serve small-scale applications, but the fuel cell deterioration progresses rapidly

Engineering Contradiction:
Improvepower output capabilityVSAvoidfuel cell durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces a battery as an intermediary energy storage device between the fuel cell and the load. The battery absorbs fluctuations in power demand, allowing the fuel cell to operate at optimal power levels while the battery handles variable load requirements, thus preventing rapid deterioration during low-power operations

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically changes the operating parameters of the fuel cell by controlling its power output based on load conditions and battery state of charge. The fuel cell operates at high power when the battery needs charging and at reduced or zero power when the battery can meet demand, avoiding prolonged low-power operation that causes deterioration

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the fuel cell is prevented from generating below a predetermined power to suppress deterioration, then fuel cell durability is improved, but the output range of the fuel cell system is limited

Engineering Contradiction:
Improvefuel cell durabilityVSAvoidoutput range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system achieves multi-functionality by combining the fuel cell and battery into a hybrid power system. The fuel cell provides stable base power while the battery provides supplemental power for low-demand periods, enabling the system to serve both high-power and low-power applications without limiting the overall output range

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system dynamically switches between different operational modes (fuel cell only, battery only, combined) based on real-time conditions. This dynamic operation allows the fuel cell to maintain its power output above the predetermined threshold while the system as a whole can still meet varying power demands through coordinated battery operation

Inventive Principle:
Principle #15Dynamics

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 expands the output range of the fuel cell system while effectively preventing deterioration by optimizing power generation and storage, ensuring stable operation across varying power demands.

Implementation Method 1

a battery that stores power output from the fuel cell

Methodology Applied
Scientific EffectBattery (electricity): Battery (electricity)

Implementation Method 2

a fuel cell system including a fuel cell

Methodology Applied
Scientific EffectFuel cell: Fuel Cell

Data Source

PatentEP4708412A1Control method for fuel cell system, control program for fuel cell system, fuel cell system, and monogeneration device
Publication Date: 2026.03.11 YANMAR HLDG CO LTD
  • EP4708412A1 patent drawingFigure 1
  • EP4708412A1 patent drawingFigure 2
  • EP4708412A1 patent drawingFigure 3A

AI summary

[Problem] Provided is a technique capable of expanding an output range of a fuel cell system while suppressing deterioration of a fuel cell. [Solution] A fuel cell system includes a fuel cell, and a battery that stores power output from the fuel cell, and has a first operation mode in which power output from the fuel cell is extracted to the outside, and a second operation mode including a discharge mode in which power output from the battery is extracted to the outside. A control method for a fuel cell system includes switching between the first operation mode and the second operation mode based on target power of the fuel cell.