Technology, Development Status and application examples of locally resolved current density measurements for online-monitoring of the Performance of water electrolyser

Biswas, Indro

Garcia Sanchez, Daniel

Schulze, Mathias

Institute of Transport Research:Publications

Monitoring of current density distribution I. Biswas, D. Garcia Sanchez, M. Schulze German Aerospace Center (DLR) Institute of Engineering Thermodynamics Electrochemical Energy Technology Stuttgart, Germany Outline • Current Density • Local current density monitoring – technology principles and origins in fuel cell technology • INSIDE – Diagnostics in Electrolysis • Application examples • Outlook  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  3 Current Density  o Key point indicator for electrolysers and fuel cells:  efficiency of used materials (PGMs, etc. ) o Faraday´s Law: Current density  equals  chemical turnover o Local electrochemical turnover is determined by  local catalytic activity  local transport limitations local degradation local temperature local…  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  4 Technology: Segmented Printed circuit boards  o Origin: PEM Fuel cells o PCB mimicks bipolar plate o Endplate contact possible o Gas tightness o Current take up 8 A/cm² o Resistor shunt o Recording of shunt voltage o Additional T sensors (local) o Local EIS (single segment readout) o Operating temperature max 200°C  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  5 Technology: Segmented Printed circuit boards  o Milling of flow fields possible o Limit to local resolution by • Flow field • PCB layout / thickness / connectors • Data acquisition  4 mm  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  6 Technology: Segmented Printed circuit boards  Lab scale single test cell  25 cm², 49 segments  Fuel cell stack size  >150 cm², 108 segments  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  7 Technology: Segmented Printed circuit boards  Application  o Systematic studies on fuel cell o Optimization of Performance o Malfunctioning o Humidification o Heat dissipation o Oscillating chemical reactions o Flow field evaluation o GDL enhancement  Flooding event in PEMFC  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  8 INSIDE – In-situ Diagnostics for Water Electrolysers  R&D Project funded by FCH JU: Adaptation of segmented PCB to • PEMWE • AWE • AEMWE Consortium: 5 partners • Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) • NEL Hydrogen ASA, Norway • Heliocentris Italy S.r.l., Italy • CNRS / Université de Strasbourg, France • Hochschule Esslingen, Germany   Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  9 INSIDE – In-situ Diagnostics for Water Electrolysers   PEMWE AEMWE AWE Grid stabilisation: - Supply based operation - Flexibility (KPI 5) - Durability (KPI 3, 4) Industry: - Demand based operation - Efficiency (KPI 1, 2) Targetted  development  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  10 INSIDE – In-situ Diagnostics for Water Electrolysers  Objectives  Provide in-operando monitoring for • Harvesting of hidden performance  • Revealing hidden deficiencies • Enhancing durability  • Preventing critical operation • Targeted developments • Evaluation of modellling • Evaluation of AST Stress Tests INSIDE Diagnostic Tool Improved Operation Strategies Enhanced performance & lifetime in-operando Investigation of Degradation Correlation:  Operation Conditions & Degradation ex-situ  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  11 INSIDE – In-situ Diagnostics for Water Electrolysers  Challenges & Achievements  Contact Resistance: PCB – instead of BPP Carbon GDLs vs. metal foams/felts Increase of gold coating thickness graphitic coating (under development)  Differential Pressure adjust PCB thickness add regular BPP  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  12 INSIDE – In-situ Diagnostics for Water Electrolysers  Challenges & Achievements  Number of data recording channels Space requirements: PCB circuits compete with hardware  More complex layouting More PCB layers  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  13 INSIDE – In-situ Diagnostics for Water Electrolysers  Challenges & Achievements  AEMWE prototype: Gas & electrolyte tightness • Pressure adapt sealing concept • Surfaces metal coating  Prototype for AEMWE  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  14 INSIDE – In-situ Diagnostics for Water Electrolysers  Challenges: Corrosion  • AWE conditions (30%KOH, >60°C) Sealings barely stop KOH lye Lye migrates along copper lines when accessible  • PCB material itself (FR4 epoxy) can be attacked Invasion between laminated layers avoid exposure  or seal edges of PCB  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  15 INSIDE – In-situ Diagnostics for Water Electrolysers  Data acquisition  • Voltage recording • Modular setup • Multiplexer for up to 560 channels • USB interface • Labview ™ compatibility Data acquisition : Keysight (HP/Agilent) 34980A   Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  16 INSIDE – In-situ Diagnostics for Water Electrolysers  Data acquisition & visualisation  Overall values  Local current densities   Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  17 Examples for Application (25 cm² test cells): Contact resistance and pressure  2.2Nm  0.5Nm  (Manuscript in  preparation) MEA: Greenerity E400E (Nafion 115) Anode GDL: Sinter titanium    Cathode GDL: Carbon paper A/cm²  >1.5 1.5      1.0       0.5        0.0  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  18 Examples for Application: Flow field evaluation   Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  19 Examples for Application: Water starvation  WP4 – PEM electrolysers Parallel G T = 80°C  P = 1 bar  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  20 Examples for Application: Irreversible Degradation  1day  2 day  3 day  225230235240Binding Energy /eV A1 Kathode D4 Kathode G7 KathodeLocal post-mortem investigations (XPS):  Mo traces in cathode catalyst layer,  correlating with local irreversible degradation   Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  21 Summary and Outlook  o In-operando Diagnostics  o Visualisation o Little disturbance o Costs depend on upscaling & data acquisition o Application: o Development (Materials, Designs) o Monitoring • Steady monitoring • Response to diagnostic cycles o Evaluation of numerical modelling o Evaluation of testing protocols & ASTs  Workshop “Diagnostics in Electrolysis”, 16. Jun 2017  22 Acknowledgements INSIDE consortium  Magnus Thomassen Anders Søreng Chiara Emiliani Siegfried Limmer Elena Savinova Viktoriia Saveleva Renate Hiesgen Tobias Morewietz Mathias Schulze EWII  Laila Grahl-Madsen Theiss Stenstrøm Bertil Sieborg     People at DLR  Daniel Garcia Sanchez Olivier Garrot Michael Gnilka FCH JU  The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) for Fuel Cell and Hydrogen Joint Technology Initiative under Grant  No. 621237 (INSIDE). Thank you for your attention! 

Monitoring of current density distribution

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