The composition of hydrogen delivered to fuel cell electric vehicles (FCEVs) has a significant impact on fuel cell stack durability and system efficiency. International standards dealing with hydrogen quality specifications have been created (ISO 14687-2:2012 and ISO 14687-3:2014) and the former is currently under revision (ISO TC 197/WG 27&28).
The contaminants included in these standards are primarily associated with hydrogen production and purification processes. European and international research efforts have been contributing to better understanding of the effects of such contaminants (e.g. CO, HCHO, HCOOH) and their maximum acceptable levels are already relatively well understood. Nevertheless, most of these investigations are conducted using individual contaminants under static operation conditions, at relatively low maximum current density (1 A cm-2), and not necessarily with MEA configurations appropriate for future automotive applications.
Furthermore, contaminants originating from hydrogen refuelling stations (HRS) may also impact the quality of hydrogen delivered to FCEVs. The effects of irreversible contaminants (sulphur, halogenates such as tetrachlorohexafluorobutane, contaminants from ionic compression, etc.) as well as those arising from HRS operation and maintenance are less well known. A major issue with some of these contaminants (e.g. grease from compressors) is that relatively large amounts of contaminant can be introduced into the hydrogen due to improper maintenance procedures or component failure.
The main focus of the project should be to understand the effect of contaminants originating from the hydrogen supply chain, as specified in current standards ISO 14687-2:2012 and ISO 14687-3:2014, on fuel cell performance and durability under dynamic load cycle conditions. MEA configurations representative of state-of-the-art transport applications shall be utilised.
A particular challenge concerns the identification and characterisation of contaminants originating from the HRS (TRL 8) and their impact on fuel cell performance and durability.
Based on the results, mitigation methods (e.g. in-line monitoring of hydrogen quality at HRS) should be developed and appropriate revision of ISO 14687-2:2012 proposed. A major focus should be on avoiding the use of ‘total’ parameters where possible. The work will also support revision of ISO 14687-3:2014.
Tolerance levels for impurities depend on the fuel utilisation and load profile of the PEMFC. Therefore, the susceptibility to contaminants should be characterised at PEMFC system level, using realistic automotive conditions and drive cycles, including frequent voltage and start-stop cycling as well as very high maximum current densities (2.5 A cm-2). The susceptibility to contaminants should be characterised using representative fuel utilisation rates, including enrichment of contaminants in the anode recirculation loop. Ultra-low anode PGM loadings (0.02 mg cm-2 or less) should be included to support minimising use of PGM and provide information for future revisions of ISO 14687 standards.
The project should address the following key issues:
The proposal should establish a link to the FCH2-JU project HyCoRA, in order to ensure complementarity and adequate take-up of its outputs, including the utilisation and further development of the qualitative and quantitative risk assessment approach of the HyCoRA project.
The subject addressed in this topic has been identified as a priority by many countries working on hydrogen and fuel cells. Collaboration with relevant international partners is recommended.
A collaboration mechanism needs to be developed with the JRC, in relation to the ongoing EU protocol harmonisation and validation activities performed in support of the FCH2-JU programme.
All deliverables and data should be public in order to support standardisation work as effectively as possible. Data anonymisation should be avoided.
Any safety-related event that may occur during execution of the project shall be reported to the European Commission's Joint Research Centre (JRC), which manages the European hydrogen safety reference database, HIAD (dedicated mailbox JRC-PTT-H2SAFETY@ec.europa.eu).
The FCH2-JU considers that proposals requesting a contribution from the EU of EUR 3.5 million would allow this specific challenge to be addressed appropriately. Nonetheless, this does not preclude submission and selection of proposals requesting other amounts.
A maximum of 1 project may be funded under this topic.
Expected duration: 3 years
The proposed developments will improve understanding of contaminant effects, and thus present an important base for appropriate future hydrogen standards. This understanding will also support the discussion of "hydrogen quality requirements vs affordable hydrogen costs".
Successful development and application of in-line continuous monitoring of hydrogen impurities would reduce the incidence of poor vehicle performance and potential loss of reputation of fuel cell technology.
The expected impacts of the project include: