Fuel Cell Stop Charging Control to Limit Start-Stop Degradation

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Solution Overview

Problem

Frequent vehicle stops negatively affect the durability and lifetime expectancy of fuel cell systems in fuel cell electric vehicles (FCEVs) due to frequent deactivation and operation at low power levels.

Innovation Solution

A computer system that controls a fuel cell system during vehicle stops by calculating the storage capacity of the vehicle battery, determining the maximum feasible fuel cell power output, and adjusting the charging mode based on this power output to minimize degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the fuel cell system is frequently deactivated during vehicle stops, then energy consumption is reduced, but the durability and lifetime expectancy of the fuel cell system deteriorates

Engineering Contradiction:
Improveenergy consumptionVSAvoiddurability and lifetime expectancy
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The control system predicts the upcoming stop duration in advance using navigation data and historical information. Based on this prediction, it proactively adjusts the fuel cell operating strategy before the stop occurs, ensuring the fuel cell maintains optimal operating conditions during brief stops and can be safely deactivated during longer stops, thus preventing degradation while managing energy consumption

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the fuel cell operating mode based on real-time conditions and predicted stop duration. It transitions between different operating states (active, standby, deactivated) and power levels according to the predicted stop characteristics, allowing optimal balance between energy savings and durability preservation for each specific stop scenario

Inventive Principle:
Principle #15Dynamics

2Use of energy by moving object

If the fuel cell system operates at low power levels during vehicle stops, then energy consumption is reduced, but the fuel cell performance and efficiency deteriorates

Engineering Contradiction:
Improveenergy consumptionVSAvoidfuel cell efficiency
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

Instead of completely deactivating the fuel cell during all stops, the system applies partial action by maintaining reduced but non-zero power output during brief stops. This partial operation prevents the harmful effects of complete shutdown while consuming minimal energy, avoiding both the energy waste of full operation and the degradation risks of complete deactivation

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system changes operational parameters (power level, operating mode) based on the predicted stop duration. For short stops, it maintains elevated power levels; for medium stops, it transitions to standby mode; for long stops, it deactivates the fuel cell. This parameter adjustment optimizes the balance between energy consumption and efficiency preservation for each stop scenario

Inventive Principle:
Principle #35Parameter changes

3Speed

If the fuel cell system is kept active during vehicle stops, then responsiveness to resume driving is improved, but energy consumption increases

Engineering Contradiction:
ImproveresponsivenessVSAvoidenergy consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The system dynamically selects the fuel cell operating state based on the predicted stop duration. For very short stops, it maintains active operation to ensure immediate responsiveness. For longer stops, it transitions to standby or deactivated states to save energy, with automated restart capability. This dynamic adjustment optimizes the trade-off between responsiveness and energy consumption for each stop scenario

Inventive Principle:
Principle #15Dynamics

4Adaptability or versatility

If the fuel cell system undergoes frequent start-stop cycles, then adaptability to varying driving conditions is improved, but the durability and lifetime expectancy deteriorates

Engineering Contradiction:
Improveadaptability to varying driving conditionsVSAvoiddurability and lifetime expectancy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The control system uses predictive information from navigation systems and historical data to anticipate stop events before they occur. This preliminary knowledge allows the system to plan fuel cell operation strategies in advance, minimizing unnecessary start-stop cycles by keeping the fuel cell active during predictable short stops while only deactivating during confirmed longer stops, thus reducing degradation while maintaining adaptability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors actual stop durations and compares them with predicted values, using this feedback to refine future predictions and adjust operating strategies. It learns from past stop patterns to improve the accuracy of predicted stop durations, enabling progressively better optimization between adaptability and durability as the system accumulates operational data

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 fuel cell degradation, improves efficiency, lifespan, responsiveness, safety, and adaptability to different fuels and loads by optimizing the power output during vehicle stops.

Implementation Method 1

a fuel cell stack that converts hydrogen into electricity to power an electric motor

Methodology Applied
Scientific EffectElectrochemical conversion: Fuel Cell

Implementation Method 2

a vehicle battery that stores electrical energy and releases it to supplement power during high-demand periods

Methodology Applied
Scientific EffectElectrical energy storage: Battery (electricity)

Data Source

PatentEP4552903A1Control of a vehicle fuel cell system during a vehicle stop
Publication Date: 2025.05.14 VOLVO TRUCK CORP
  • EP4552903A1 patent drawingFigure 1
  • EP4552903A1 patent drawingFigure 2
  • EP4552903A1 patent drawingFigure 3

AI summary

A computer system (100) for controlling a fuel cell system (20) during a vehicle stop of a vehicle (10), the computer system (100) comprising processing circuitry (102) configured to: obtain a stop duration of the vehicle stop; calculate a storage capacity of a vehicle battery (32) of the vehicle (10) as a difference between a current state of charge of the vehicle battery (32) and a target state of charge of the vehicle battery (32) at the end of the stop duration; calculate a battery charging energy for the vehicle battery (32) based on the storage capacity; determine a maximum feasible fuel cell power output of the fuel cell system (20) for charging the vehicle battery (32) using the battery charging energy; and control a charging mode of the fuel cell system (20) based on the maximum feasible fuel cell power.