# US 2020/0403249 A1 · Locally engineered pem cells components with optimized operation for improved durability > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0403249 A1 - Document ID: US20200403249A1 - Status: Published application - Kind: A1 - Application number: 16/623,221 - Filed: 2017-06-19 - Published: 2020-12-24 - Earliest claimed: 2017-06-19 - Assignees: Politecnico Di Milano - Applicants: Politecnico Di Milano - Inventors: Andrea CASALEGNO; Claudio RABISSI; Laila GRAHL-MADSEN - Web page: https://patentgrep.com/patent/US20200403249A1 ## CPC - H01M 4/8642: {Gradient in composition} - C25B 9/23: comprising ion-exchange membranes in or on which electrode material is embedded - C25B 9/60: Constructional parts of cells - C25B 15/02: Process control or regulation - C25B 15/08: Supplying or removing reactants or electrolytes; Regeneration of electrolytes - H01M 4/8636: {with a gradient in another property than porosity (H01M4/861 takes precedence)} - H01M 4/92: Metals of platinum group (H01M4/94 {, H01M4/9058} take precedence) - H01M 8/023: Porous and characterised by the material - H01M 8/04358: {of the coolant} - H01M 8/04388: {of anode reactants at the inlet or inside the fuel cell} - H01M 8/04395: {of cathode reactants at the inlet or inside the fuel cell} - H01M 8/04417: {of the coolant} - H01M 8/045: {of anode reactants at the inlet or inside the fuel cell} - H01M 8/04507: {of cathode reactants at the inlet or inside the fuel cell} - H01M 8/04328: {of anode reactants at the inlet or inside the fuel cell} - H01M 8/04335: {of cathode reactants at the inlet or inside the fuel cell} - H01M 2008/1095: {Fuel cells with polymeric electrolytes} - Y02E 60/50: Fuel cells - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A PEM fuel or electrolysis cell with an extended lifetime, improved performance and uniform and stable operation is disclosed wherein a membrane electrode assembly is provided with a gradient of one or more properties in combination with a modification of one or more control parameters of the cell during its operation. ## Claims ### Claim 1 A PEM fuel or electrolysis cell comprising: at least a reactant supply circuit comprising: a reactant inlet and a reactant outlet, an oxidant supply circuit having an oxidant inlet and an oxidant outlet, a cooling circuit comprising a coolant inlet and a coolant outlet and a membrane electrode assembly, said membrane electrode assembly comprising an electrolyte membrane coated with an anode side and a cathode side catalyst layer, and anode side and cathode side gas diffusion layer each coating the respective catalyst layer, wherein said membrane electrode assembly comprises: a gradient of at least one property of at least a component thereof, and a tuner modifying at least one control parameter of the cell during operation of the cell. ### Claim 2 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said component is a catalyst layer. ### Claim 3 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said gradient is a gradient of catalyst loading per unit of surface of at least one catalyst layer. ### Claim 4 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said gradient is a gradient of ionomer loading per unit of surface of at least one catalyst layer. ### Claim 5 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said gradient is a gradient of thickness of at least one catalyst layer. ### Claim 6 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said gradient has a parabolic trend. ### Claim 7 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said component is a gas diffusion layer. ### Claim 8 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said gradient is a gradient of hydrophobicity of at least one gas diffusion layer. ### Claim 9 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said component is an anode side component. ### Claim 10 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said component is a cathode side component. ### Claim 11 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said control parameter is the flow rate, temperature, relative humidity or pressure of the reactant. ### Claim 12 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said control parameter is the flow rate, temperature, relative humidity or pressure of the oxidant. ### Claim 13 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said flow rate is gradually increased during operation of the cell. ### Claim 14 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said control parameter is the average working temperature of the cell or flow rate or inlet temperature of coolant. ### Claim 15 (depends on 1) The PEM fuel or electrolysis cell according to claim 1, wherein said tuner comprises a programmable electronic control unit controlling parameters of reactant and/or oxidant circuit and/or the cell as a function of the selected gradient of said at least one property of at least a component thereof. ### Claim 16 A method of optimization of a PEM fuel or electrolysis cell, wherein it comprises following steps: characterization of current density distribution and local electrochemical impedance analysis of the cell to be optimized accordingly to the invention, performed during reference condition operation, over a testing period long enough to appreciate the degradation mechanisms hindering local performance and identifying the most limited areas of the cell; characterization of current density distribution and local electrochemical impedance analysis of the cell to be optimized accordingly to the invention, performed during steady state analysis varying a selection of the most influencing operation control parameters, in order to evaluate the influence of such variations on local operation; development of improved components having gradients in properties, basing the development on the former investigations, developing altogether a draft operating strategy for the optimized component, said development being based on modelling of the improvements to simulate their impact on local performance, optimizing local material properties and operating conditions; and characterization of current density distribution and local electrochemical impedance analysis of the cell including the optimized components with properties gradient and definition of the corresponding optimized operating protocol aiming to the maximum uniformity in current density distribution over the cell active area during cell operation. ### Claim 17 (depends on 16) The method of optimization of a PEM fuel or electrolysis cell according to claim 16, wherein a segmented cell is used for said characterization.