Battery monitoring circuit, apparatus and method
First Claim
1. An energy storage cell apparatus, comprising:
- a plurality of battery cells;
a current injection circuit configured to separately inject current into individual ones of the plurality of battery cells;
an impedance-detection circuit coupled to detect an impedance characteristic of the plurality of battery cells responsive to the injected current therein;
a data extraction circuit coupled to the impedance-detection circuit and configured to;
receive high-bandwidth impedance data regarding the detected impedance characteristic from the impedance-detection circuit,separate low-frequency components of the impedance data from higher-frequency components of the impedance data, andextract impedance information for the plurality of battery cells from the high-bandwidth impedance data; and
an output circuit configured to provide the low-frequency components and the extracted impedance information as an output indicative of impedance characteristics of the energy storage cell apparatus.
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Accused Products
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).
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Citations
19 Claims
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1. An energy storage cell apparatus, comprising:
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a plurality of battery cells; a current injection circuit configured to separately inject current into individual ones of the plurality of battery cells; an impedance-detection circuit coupled to detect an impedance characteristic of the plurality of battery cells responsive to the injected current therein; a data extraction circuit coupled to the impedance-detection circuit and configured to; receive high-bandwidth impedance data regarding the detected impedance characteristic from the impedance-detection circuit, separate low-frequency components of the impedance data from higher-frequency components of the impedance data, and extract impedance information for the plurality of battery cells from the high-bandwidth impedance data; and an output circuit configured to provide the low-frequency components and the extracted impedance information as an output indicative of impedance characteristics of the energy storage cell apparatus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A monitoring circuit for monitoring a battery pack having a plurality of battery cells connected in series, the monitoring circuit comprising:
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a current injection circuit configured to separately inject current into individual ones of the plurality of battery cells; a voltage detection circuit configured to provide, for each of the battery cells, an output indicative of cell voltage of the battery cell responsive to the injected current; a current detection circuit configured to provide an output indicative of current through a circuit connected in series with the battery cells and therein indicate current through the battery cells; an extraction circuit configured to extract amplitude and phase characteristics of the outputs of the current and voltage detection circuits, to provide an indication of an impedance characteristic of the cells responsive to the injected current; first and second low-frequency filter circuits respectively configured to separate low-frequency components of the output of the voltage and current detection circuits from higher-frequency components of the output of the voltage and current detection circuits, the low-frequency components indicative of a state of charge (SoC) for the battery cells and a low-frequency part of an impedance curve for a battery cell; and a battery pack controller coupled to receive the low-frequency components from the first and second low-frequency filter circuits and configured to use the low-frequency components to estimate the SoC for the battery cells. - View Dependent Claims (14, 15)
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16. A method for monitoring a battery pack having a plurality of battery cells connected in series, the method comprising, in a battery pack circuit:
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separately injecting current into individual ones of the plurality of battery cells; providing, by a voltage detection circuit, for each of the battery cells, an output indicative of cell voltage of the battery cell responsive to the current injected into the battery cell; providing, by a current detection circuit, an output indicative of current through each of the battery cells; extracting amplitude and phase characteristics of the current and voltage outputs for each of the cells, to provide an indication of an impedance characteristic of the cells; separating low-frequency components of the output of the voltage and current detection circuits from higher-frequency components of the voltage and current detection circuits, the low-frequency components indicative of a state of charge (SoC) for the battery cells and a low-frequency part of an impedance curve for a battery cell; and receiving the low-frequency components from filter circuits and using the low-frequency components to estimate the SoC for the battery cells. - View Dependent Claims (17, 18, 19)
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Specification