Electrochemical impedance spectroscopy modeling using the dis-tribution of relaxation times and error analysis for fuel cells

• Autor(es): Lopes, Vitor V. ; Rangel, C. M. ; Novais, Augusto Q.
• Data: 2013
• Identificador Persistente: http://hdl.handle.net/10400.9/1995
• Origem: Repositório do LNEG
• Assunto(s): Fuel cells; Impedance spectroscopy; Distribution relaxation times; Parameter estimation; Residuals bootstrap
• Tipo de Documento: Objeto de conferência
• Idioma: Inglês
• Contribuidor(es): Repositório do LNEG

Descrição

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.