Electrochemical impedance spectroscopy modeling using the dis-tribution of rela...

• Author(s): Lopes, Vitor V. ; Rangel, C. M. ; Novais, Augusto Q.
• Date: 2013
• Persistent ID: http://hdl.handle.net/10400.9/1995
• Origin: Repositório do LNEG
• Subject(s): Fuel-cell ; Impedance spectroscopy; Distribution of relaxation times; Parameter estimation; Residuals bootstrap
• Document Type: Conference Object
• Language: English

Description

This paper proposes a new approach to determine the distribution of relaxation times (DRT) directly from the electro-chemical impedance spectroscopy (EIS) data, i.e. without the use of an equivalent electrical circuit model. The method uses a generalized fractional-order Laguerre basis to represent EIS where both the parameters of the basis and their co-efficients are estimated by solving a nonconvex minimization problem. Furthermore, the DRT confidence region is de-termined to assess the accuracy and precision of the DRT estimate. The approach is applied to analyze the dominant dynamic properties of an open-cathode hydrogen fuel-cell under different current and air-flow conditions. Results showed that the estimated DRT closely reconstructs EIS data even when there is a higher variance at smaller relaxation times.