BATTERY CELL IMPEDANCE MEASUREMENT METHOD AND APPARATUS
First Claim
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, with N sample values representing each period of the sine waveform and N sample values representing each period of the cosine waveform;
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; 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.
2 Assignments
0 Petitions
Accused Products
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.
-
Citations
20 Claims
-
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, with N sample values representing each period of the sine waveform and N sample values representing each period of the cosine waveform; 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; 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method for determining impedance of a battery cell, the method comprising:
-
generating sine and cosine waveforms, each period of each of the waveforms having N sample points; for each sample point of the cosine waveform; injecting a current having an amplitude corresponding to a value of the sample point into a battery cell; converting a voltage level across the cell from an analog to a digital value; and separating the digital value of the voltage into real and imaginary components; summing the real component of N digital values to determine a real component of the impedance of the battery cell; and summing the imaginary component of the N digital values to determine an imaginary component of the impedance of the battery cell. - View Dependent Claims (13, 14, 15, 16)
-
-
17. An energy storage cell arrangement, comprising:
-
a plurality of battery cells coupled in series; and an impedance detection circuit coupled to one of the plurality of battery cells, the impedance detection circuit including; a first circuit configured to generate sample values representative of a sine waveform and a cosine waveform, with N sample values representing each period of the sine waveform and N sample values representing each period of the cosine waveform; a second circuit coupled to an output of the first circuit and configured to input a current into the one of the plurality of battery cells 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 one of the plurality of battery cells and configured to sample voltage levels across the one battery cell resulting from the current being input into the one battery cell; and a fourth circuit coupled to an output of the third circuit and configured to; multiply each voltage level sampled by the third circuit with the sine waveform of the first circuit to generate the imaginary component; multiply each voltage level sampled by the third circuit with the cosine waveform of the first circuit to generate the real component; sum the real component of N of the voltage levels sampled by the third circuit to determine a real component of the impedance of the one battery cell; and sum the imaginary component of the N of the voltage levels sampled to determine an imaginary component of the impedance of the one battery cell. - View Dependent Claims (18, 19, 20)
-
Specification