Locally engineered pem cells components with optimized operation for improved durability

Patent metadata

Field	Value
Publication number	US-2020403249-A1
Application number	US-201716623221-A
Country	US
Kind code	A1
Filing date	Jun 19, 2017
Priority date	Jun 19, 2017
Publication date	Dec 24, 2020
Grant date	—

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.

First 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.

2 . The PEM fuel or electrolysis cell according to claim 1 , wherein said component is a catalyst layer.

3 . 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.

4 . 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.

5 . The PEM fuel or electrolysis cell according to claim 1 , wherein said gradient is a gradient of thickness of at least one catalyst layer.

6 . The PEM fuel or electrolysis cell according to claim 1 , wherein said gradient has a parabolic trend.

7 . The PEM fuel or electrolysis cell according to claim 1 , wherein said component is a gas diffusion layer.

8 . 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.

9 . The PEM fuel or electrolysis cell according to claim 1 , wherein said component is an anode side component.

10 . The PEM fuel or electrolysis cell according to claim 1 , wherein said component is a cathode side component.

11 . 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.

12 . 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.

13 . The PEM fuel or electrolysis cell according to claim 1 , wherein said flow rate is gradually increased during operation of the cell.

14 . 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.

15 . 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.

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.

17 . The method of optimization of a PEM fuel or electrolysis cell according to claim 16 , wherein a segmented cell is used for said characterization.

Assignees

• Milano Politecnico

Inventors

• Casalegno Andrea
• Rabissi Claudio
• Grahl-Madsen Laila

Classifications

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/04507

  of cathode reactants at the inlet or inside the fuel cell · CPC title

• H01M8/023

  Porous and characterised by the material · CPC title

• H01M4/8636

  with a gradient in another property than porosity (H01M4/861 takes precedence) · CPC title

• H01M8/04395

  of cathode reactants at the inlet or inside the fuel cell · CPC title