Why do battery impedances increase at low frequencies?

6.3.4. Diffusion region The increment of the battery impedance spectrum at low frequencies is mostly attributed to the structural disordering of the electrode , . This disordering further leads to the depletion of the cathode's active material during the battery's deterioration process.

Why do we measure battery impedance at high frequencies?

Consequently, measuring the impedance at high frequencies can lead to more precise and reliable estimation outcomes. It is also noticed that the impedance at medium frequencies exhibits significant sensitivity to changes in battery temperature.

Does a low SoC affect battery impedance?

Nevertheless, when the battery has a low SOC (Fig. 7 a), the duration of rest has a discernible impact on the impedance outcomes. Notably, the medium-frequency semicircle observed at 10 s is considerably smaller compared to other relaxation periods.

Do battery impedance characteristics depend on frequency?

Schmidt et al. reveal that the sensitivity of battery impedance characteristics is contingent upon the frequency range used for the test. Battery impedance responses have a noticeable dependency on temperature and SOC at low frequencies, while this dependence becomes less apparent at high frequencies.

What causes deterioration of battery performance in high-frequency range?

The deterioration of battery performance in the high-frequency range is mostly attributed to the depletion of lithium resources, primarily caused by the growth and decomposition processes of the SEI film, as well as the degradation of battery graphite .

Why are battery impedance responses difficult to elucidate?

Thirdly, battery impedance responses exhibit intricate interconnections with numerous processes, making them challenging to elucidate. To resolve the issue, it is necessary to develop a comprehensive impedance model for complex scenarios. This could facilitate the state estimation process and aid in interpreting the impedance proprieties.