Fuel Cell Freeze Protection During Vehicle Stopovers

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Solution Overview

Problem

Fuel cells in vehicles are susceptible to degradation and damage from ice formation during sub-zero temperatures, leading to performance loss and reduced lifetime, and existing freeze protection methods can contribute to further degradation.

Innovation Solution

A method for managing fuel cell systems in vehicles by determining whether and when to perform freeze protection based on factors such as vehicle stopover duration, ambient conditions, power needs, and hydrogen consumption costs, allowing for informed decisions on shutting down, keeping, or restarting fuel cell systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If freeze protection is performed frequently to protect fuel cells from ice formation, then reliability is improved, but the fuel cells suffer from degradation and performance loss

Engineering Contradiction:

Improvefuel cell reliabilityVSAvoidfuel cell performance

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The system performs preliminary assessment of freeze risk by evaluating ambient temperature, vehicle stopover duration, and fuel cell state before shutdown. Freeze protection is only activated when the assessed risk exceeds a threshold, preventing unnecessary protection actions that would cause degradation while still protecting against actual freeze risks

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the freeze protection decision based on changing parameters including ambient temperature, stopover duration, fuel cell temperature, and state of charge. This adaptive approach allows the system to optimize between protection and degradation prevention under different operating conditions

Inventive Principle:

Principle #35Parameter changes

2Duration of action of stationary object

If the fuel cell system is kept operational to avoid freeze protection, then fuel cell lifetime is improved, but hydrogen consumption increases

Engineering Contradiction:

Improvefuel cell lifetimeVSAvoidhydrogen consumption

Core Design Contradiction:

Duration of action of stationary objectVSUse of energy by moving object

Solution Approach 1:

The system calculates an estimated stopover duration before shutdown and compares it against a threshold duration. If the estimated stopover is shorter than the threshold, the fuel cell is kept operational to avoid the degradation associated with freeze protection cycles, accepting the hydrogen consumption as a trade-off for extended lifetime

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically switches between two operational modes: keeping the fuel cell running during short stopovers versus shutting down and applying freeze protection during long stopovers. This dynamic decision-making optimizes the balance between hydrogen consumption and fuel cell lifetime based on real-time conditions

Inventive Principle:

Principle #15Dynamics

3Reliability

If freeze protection is implemented during short stopovers, then fuel cell protection is improved, but unnecessary degradation occurs

Engineering Contradiction:

Improvefuel cell protectionVSAvoidfuel cell degradation

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The system performs preliminary estimation of stopover duration using multiple sources including driver input, calendar time calculations, and GPS-based geofencing. This preliminary assessment allows the system to predict whether freeze protection will be necessary before actually shutting down, avoiding unnecessary protection actions during short stopovers

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system replaces traditional mechanical freeze protection switches with an intelligent control system that uses sensors, processors, and communication networks to assess freeze risk and automatically make protection decisions, enabling more nuanced and accurate determination of when protection is actually needed

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20260038855A1Controlling freeze protection for a fuel cell vehicle

Publication Date: 2026.02.05 VOLVO TRUCK CORP

AI summary

A computer-implemented method controls a power assembly of a vehicle having a plurality of fuel cell systems and an electric energy storage system. The method includes estimating a duration of a vehicle stopover of the vehicle; determining whether a freeze protection is required during the vehicle stopover; and, if it is determined that the freeze protection is not required, shutting down the fuel cell system without enabling the freeze protection. If it is determined that the freeze protection is required, the method may comprise estimating a threshold time indicating a time at which a cost of keeping the fuel cell systems operational outweighs a cost of shutting down the fuel cell systems; and if the estimated duration of the vehicle stopover expires after the threshold time, shutting down the fuel cell systems and enabling the freeze protection.