Battery phase meter to determine internal temperatures of lithium-ion rechargeable cells under charge and discharge
First Claim
1. A method of measuring an internal temperature of a lithium-ion rechargeable cell, comprising:
- applying an alternating signal to the cell to generate a phase-shifted alternating signal at the cell;
detecting the phase shift as a phase difference between a frequency of the applied alternating signal and a frequency of the phase-shifted alternating signal; and
determining the internal temperature of the cell based on the phase difference;
wherein the applying includes one or more of applying an alternating current to generate a phase phase-shifted alternating voltage, and applying an alternating voltage to generate a phase phase-shifted alternating current.
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Accused Products
Abstract
Methods and systems to determine an internal temperature of a rechargeable lithium-ion cell based on a phase shift of the cell. Internal cell temperature may be determined with respect to an internal anode temperature and/or an internal cathode temperature. Internal anode temperature may be determined based on a phase shift of a frequency within a range of approximately 40 Hertz (Hz) to 500 Hz. Internal cathode temperature may be determined based on a phase shift of a frequency of up to approximately 30 Hz. A temperature sensor as disclosed herein may be powered by a monitored cell with relatively little impact on cell charge, may be electrically coupled to cell but housed physically separate from the cell, and/or may monitor multiple cells in a multiplex fashion. A rate of change in phase shift may be used to initiate pre-emptive action, without determining corresponding temperatures.
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Citations
24 Claims
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1. A method of measuring an internal temperature of a lithium-ion rechargeable cell, comprising:
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applying an alternating signal to the cell to generate a phase-shifted alternating signal at the cell; detecting the phase shift as a phase difference between a frequency of the applied alternating signal and a frequency of the phase-shifted alternating signal; and determining the internal temperature of the cell based on the phase difference; wherein the applying includes one or more of applying an alternating current to generate a phase phase-shifted alternating voltage, and applying an alternating voltage to generate a phase phase-shifted alternating current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system to measure an internal temperature of a lithium-ion rechargeable cell, comprising:
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an alternating signal source to apply an alternating signal to the cell to generate a phase-shifted alternating signal at the cell; a phase meter to detect the phase-shift as a phase difference between a frequency of the applied alternating signal and a frequency of the phase-shifted alternating signal; and a phase-to-temperature converter to determine the internal temperature of the cell based on the phase difference; wherein the alternating signal source includes one or more of an alternating current source to generate a phase-shifted alternating voltage, and an alternating voltage source to generate a phase-shifted alternating current. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method of correlating a phase delay of a rechargeable lithium-ion cell with an internal temperature of the cell, comprising:
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applying an alternating signal to the cell when the internal temperature of the cell is at a first temperature to generate a phase-delayed alternating signal at the cell; detecting a phase difference between a frequency of the applied alternating signal and a frequency of the phase-shifted alternating signal; repeating the applying and the detecting for one or more additional internal temperatures of the cell; correlating the phase differences with the temperatures; and recording the correlations in a tangible medium; wherein the applying includes one or more of applying an alternating current to generate a phase phase-shifted alternating voltage, and applying an alternating voltage to generate a phase phase-shifted alternating current. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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23. A method of identifying a thermal condition of a lithium-ion cell, comprising:
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applying an alternating signal to the cell to generate a phase-shifted alternating signal at the cell; detecting the phase shift as a phase difference between a frequency of the applied alternating signal and a frequency of the phase-shifted alternating signal; and initiating a pre-emptive action to prevent thermal runaway when a rate of change of the phase-difference meets or exceeds a threshold rate, wherein the applying and the detecting are performed continuously or periodically. - View Dependent Claims (24)
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Specification