Impedance spectrum battery

In order to extract thermal battery parameters from a measured impedance spectrum, a thermal model of the battery is necessary. This model reproduces the effects of heat capacity, thermal conductivity, heat exchange with environment, and internal losses generation. Transient simulation is then used to calculate an impedance spectrum for the battery model which is subsequently employed for parameter identification. 

The implemented battery model is the basis for the identification of thermal cell parameters. With the battery model, TIS measurements are simulated. The same sinusoidal heat excitation as in the experiment is apphed to the thermal battery model. Simulation results dehver thermal impedances for each frequency, which form an entire impedance spectrum. The ability to simulate TIS measurements allows rapid creation of impedance spectra for arbitrary thermal cell parameters. 

A least-squares optimization routine is employed to systematically adapt the heat capacity, thermal conductivity, and convective heat exchange coefficient of the simulation model until a good agreement between measured and simulated impedance spectra is achieved. Final values of the parameter variation process represent the thermal parameters of the real battery. Figure 8 compares an impedance spectrum from measurement data with an impedance spectrum derived from the result values of the optimization process. As a good agreement... 

Figure 4.5.13. Typical impedance spectrum of a lead acid battery from lOkHz to 50/iHz. Simulation is based on data in Mauracher et al. [1997].

C. Yoon, Y. Barsukov, and J. H. Kim [2001] Method of and Apparatus for Measuring Battery Capacity by Impedance Spectrum Analysis, United States Patent 6,208,... 

Viswanathan VV, Salkind AJ, Kelley JJ, Ockerman JB (1995) Effect of state of charge on impedance spectrum of sealed cells Part D Lead acid batteries. Journal of Applied Electrochemistry 25 729-739. doi 10.1007/BF00648628... 

Usually, the ionic conductivity is much smaller than that of the electrons. To determine it, the convenient tool is the complex impedance technique, because it requires very small current (prevents heating) and very small ionic motion. The a.c. method is called electrochemical impedance spectroscopy (EIS) because the impedance spectrum measured in a wide frequency range evaluates the performance of batteries and characterizes the various elements such as electrode, electrolyte and electrolyte/electrode interface. First, let us consider the ionic conductivity in a solid electrolyte. The complex impedance due to the Li-motion is ... 

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