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Battery cell impedance measurement method and apparatus

  • US 9,128,165 B2
  • Filed: 05/04/2011
  • Issued: 09/08/2015
  • Est. Priority Date: 05/04/2011
  • Status: Active Grant
First Claim
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1. A circuit arrangement for determining impedance of a battery cell, the circuit comprising:

  • a first circuit configured to generate sample values representative of a sine waveform and a cosine waveform at a target frequency and sample rate, with each period of the sine waveform including N sample values and each period of the cosine waveform including N sample values;

    a second circuit coupled to an output of the first circuit and configured to input a current into the cell in response to the sample values of the cosine waveform, the current having an amplitude proportional to the sample values of the cosine waveform;

    a third circuit coupled to the cell and configured to sample voltage levels across the cell resulting from the current being input into the cell, the third circuit is configured to sample voltage levels at a sample rate equal to a sample rate of the cosine waveform; and

    a fourth circuit coupled to an output of the third circuit and configured to separate each voltage level sampled by the third circuit into real and imaginary components.

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