Abstract: Various aspects of the present disclosure are directed to monitoring battery cells. In accordance with various embodiments, a battery pack having a plurality of battery cells connected in series is monitored. Current is separately injected into individual ones of the plurality of battery cells, such as by operating a balancing circuit coupled across an individual cell, to inject current (e.g., positive or negative) into the cell. For each of the battery cells, an output is provided to indicate cell voltage of the battery cell responsive to the current injected therein. An output indicative of current through each of the battery cells is provided as well. From the respective outputs as corresponding to each individual cell, amplitude and phase characteristics of the current and voltage outputs for each of the cells are extracted to provide an indication of an impedance characteristic of the cell(s).

Abstract: A circuit arrangement for determining impedance of a battery cell is provided. A first circuit is configured to generate sine and cosine waveforms having N sample values per period. A second circuit is coupled to an output of the first circuit and is configured to input a current into the cell in response to the sample values of the cosine waveform. The current has an amplitude proportional to the sample values of the cosine waveform. A third circuit is coupled to the cell and configured to sample voltage levels across the cell resulting from the current being input into the cell. A fourth circuit is coupled to an output of the third circuit and is configured to separate each voltage level sampled by the third circuit into real and imaginary components.

Abstract: Various aspects of the present disclosure are directed to monitoring battery cells. In accordance with various embodiments, a battery pack having a plurality of battery cells connected in series is monitored. Current is separately injected into individual ones of the plurality of battery cells, such as by operating a balancing circuit coupled across an individual cell, to inject current (e.g., positive or negative) into the cell. For each of the battery cells, an output is provided to indicate cell voltage of the battery cell responsive to the current injected therein. An output indicative of current through each of the battery cells is provided as well. From the respective outputs as corresponding to each individual cell, amplitude and phase characteristics of the current and voltage outputs for each of the cells are extracted to provide an indication of an impedance characteristic of the cell(s).

Abstract: A circuit arrangement for determining impedance of a battery cell is provided. A first circuit is configured to generate sine and cosine waveforms having N sample values per period. A second circuit is coupled to an output of the first circuit and is configured to input a current into the cell in response to the sample values of the cosine waveform. The current has an amplitude proportional to the sample values of the cosine waveform. A third circuit is coupled to the cell and configured to sample voltage levels across the cell resulting from the current being input into the cell. A fourth circuit is coupled to an output of the third circuit and is configured to separate each voltage level sampled by the third circuit into real and imaginary components.