Durability-Lifetime of stacks for Heavy Duty trucks

The global scope is to enable in the short-term (<5 years) the deployment of competitive HD trucks based on EU fuel cell technology. The main objectives will be firstly, to clarify the durability and degradation issues of heavy duty stack components for SoA technologies (to ensure that studies are based on the most relevant up-to-date parameters, components and operating conditions for the selected applications) and, secondly, to propose and validate more durable stacks based on re-designed MEAs.

The project should rate and rank the most critical degradation mechanisms, looking for specific phenomena or stressors in stacks for heavy-duty (HD) trucks. This may be achieved using aged MEA components reflecting actual ageing from real HD operation either by collecting aged samples as well as the corresponding ageing data from field tests or actual trucks when available or mainly by performing ageing tests in labs on short stacks following realistic load profiles (full power, range extender, hybridization cases, or accelerated test), validated regarding actual, in-service drive cycles using HD-specific stack components. Applications data to be considered are: 1,000 km driving range per day; HD vehicles of classes from >12t; with power output from 150 to 350 kW and ranges from 12,000 to 100,000 km/year.

The methodology should include a broad range of investigations, with method development as needed for local in-situ measurements or ex-situ analysis, such as advanced electrochemical, physical, chemical and structural analyses, aiming to relate degradation phenomena to operating modes and conditions, quantify and correlate component degradation to performance losses. The second and major phase should be to use the results from the understanding phase to propose the best-suited mitigation strategies for the degradation mechanisms identified, concentrating the efforts on MEAs and MEA components (materials, formulations, processing), ensuring that the PGM-loading meets the target. Due to the longer lifetime required, the PGM loading target may be higher compared to LDV; hence research on how to achieve on the long term a high power density to PGM loading ratio would be of particular interest. In order to validate the proposed improvements in durability within a restricted timeframe, alternative methodologies should be proposed, such as strategies based on accelerated stress tests.

Modelling could be used to go further in the interpretation, or to simulate ageing for various MEA compositions and help defining the better trends for components formulation and stack operation. Several aspects should be covered by the project to develop disruptive MEAs and MEA components, for example by modifications of the component properties (membranes, ionomer, catalysts, gas diffusion layers) and preferably by looking for more effective utilisation of the MEAs by tuned formulations (optimised interfaces, flow-field-adapted or graded electrodes). A focus on improved durability should be the priority, while maintaining low cost and avoiding negative impact on performance. The assessment of the developments should be conducted following specified relevant protocols in representative full-size single cells and preferably stacks.

A stack performance and durability test protocol recognised by the OEMs and in-line with EU standardisation activities (in collaboration with the European Commission's Joint Research Centre (JRC) testing harmonization activities) should be applied (including minimum duration required). This validation should be done at a representative scale, at least in a short-stack of minimum 10 cells or 1 kW, with a statistically significant number of MEAs, and an MEA active area of at least 150 cm², preferably conforming with the full-power stack design. The impact on system cost over the lifetime should be assessed based on these final validation results.

The project should build on the results of previous supported projects [23] dedicated to relevant applications such as GiantLeap (addressing advanced online diagnostic, prognostic and control systems), ID FAST (addressing investigation of ageing causes and AST methodology applied on LDV), Revive (developing garbage trucks) or H2HAUL (developing FC heavy duty trucks) as well as national actions, in order to get relevant data on FC operation and degradation or aged components as starting points.
Consortia should prove their access to SoA stack designs and include the capability to assemble stacks, by involving at least two stack providers. The hardware should be available for the implementation and the test of both performance and durability of reference and developed MEAs. Project consortia should include the capability to manufacture MEAs at the SoA level to ensure correct implementation and assessment of improvements of MEA materials or components.

TRL at start of the project: 2 and TRL at the end of the project: 4.

Any safety-related event that may occur during execution of the project shall be reported to the European Commission's Joint Research Centre (JRC) dedicated mailbox JRC-PTT-H2SAFETY@ec.europa.eu , which manages the European hydrogen safety reference database, HIAD and the Hydrogen Event and Lessons LEarNed database, HELLEN.
Activities developing test protocols and procedures for the performance and durability assessment of fuel cell components should foresee a collaboration mechanism with JRC (see section 3.2.B ""Collaboration with JRC""), in order to support EU-wide harmonisation. Test activities should adopt the already published FCH 2 JU harmonized testing protocols to benchmark performance and quantify progress at programme level.

The project should contribute towards the activities of Mission Innovation - Hydrogen Innovation Challenge. Cooperation with entities from Hydrogen Innovation Challenge member countries, which are neither EU Member States nor Horizon 2020 Associated countries, is encouraged (see chapter 3.3 for the list of countries eligible for funding, and point G. International Cooperation).

The FCH 2 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.

Expected duration: 3 years

[23] https://www.fch.europa.eu/page/fch-ju-projects

Fuel cell powered heavy-duty vehicles (HDVs) hold great promise for deployment at global scale. However, for HDVs, and more specifically trucks, we face new challenges compared to Light Duty Vehicles (LDVs), especially with respect to durability and robustness. While 6,000 h lifetime is sufficient for LDVs, heavy-duty trucks will require at least five times longer. Therefore, core stack components particularly Membrane Electrode Assemblies (MEAs) need to be specifically developed in line with the specific heavy-duty truck requirements, while complying with prevailing cost targets. This improvement of the components is an essential step in order to confirm performance and durability for any full-scale stack and system design.

Increased understanding of degradation phenomena at stack level remains a major challenge to overcome in order to achieve the durability required for HD trucks. Very long lifetime is required along with high autonomy, combined with aggressive road duty cycles for some applications. Technical targets will be to further develop and apply advanced methods to properly investigate degradation of performance and the causes of these losses for the first step and, to identify, develop, realise and validate improved MEA formulations in stacks in a second step. The final outcome should thus allow significantly increased stack lifetime whilst enhancing performance and reducing cost.

The final outcome should validate the solutions developed showing clear added-value in stack durability whilst maintaining the initial performance at least as high as that achieved by the selected reference (to be defined at the beginning of the project and consistent with the current SoA, to avoid artificial improvements by using a weak starting point).

Other expected impacts should include:

• Durable cost-effective performing technical solutions for PEMFC stacks’ core components allowing to support the future implementation of European technologies in HDV systems;
• Recommendations at system level, including hybridization as appropriate, for an optimized management of the full power chain allowing to improve FC durability consistently with the targeted KPIs;
• Contribution to the targets set by the Multi-Annual Work Plan and its addendum for 2024 [24] on LDVs, particularly on stack power density (increase in kW/kg and kW/L vs. SoA) and indirectly on PEMFC system cost through stack components (reduction in €/kW vs. SoA) for heavy duty transport applications;
• Technological solutions whose economic and environmental aspects can be easily transferred to other fields compared to HDV, such as other transport or stationary applications;
• Possible contribution to RCS with regards to fuel cell testing and durability assessment.

In particular, the main targeted KPIs to be considered for the investigations are the following:

• Power density > 1.2 W/cm² at 0,675 V/cell;
• PGM loading < 0.3 g/kW;
• System durability: 30,000 projected hours with less than 10% performance loss at nominal power.

[24] https://www.fch.europa.eu/page/multi-annual-work-plan

The conditions related to this topic are provided in the chapter 3.3 of the FCH2 JU 2020 Annual Work Plan and in the General Annexes to the Horizon 2020 Work Programme 2018– 2020 which apply mutatis mutandis.