Systems and related methods for determining self-discharge currents and internal shorts in energy storage cells
First Claim
1. A method of determining a self-discharge current in an energy storage cell, the method comprising:
- applying, with a direct current (DC) voltage source, a constant test voltage to an energy storage cell without an external load connected thereto, the constant test voltage being less than an open-circuit voltage of the energy storage cell at an initial state of charge (SOC) of the energy storage cell;
measuring a test current flowing between the DC voltage source and the energy storage cell until after the test current switches from a negative current to a positive current; and
determining, with control circuitry operably coupled to a current measuring device, a self-discharge current of the energy storage cell by analyzing the measured test current, wherein the self-discharge current is indicative of a rate of internal discharge of charge stored by the energy storage cell.
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Accused Products
Abstract
Systems and methods for determining self-discharge currents in an energy storage cell and detecting internal shorts are disclosed. A system includes a DC voltage source configured to provide a constant test voltage selected to be less than an open-circuit voltage of an energy storage cell to the energy storage cell. The system also includes a current measuring device operably coupled between the DC voltage source and the energy storage cell, and control circuitry operably coupled to the current measuring device. A method includes applying the constant test voltage, and measuring the test current flowing between the DC voltage source and the energy storage cell until after the test current switches from a negative current to a positive current. The method also includes determining a self-discharge current of the energy storage cell by analyzing the measured test current with computational models that capture physical processes tied to the test methods.
16 Citations
31 Claims
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1. A method of determining a self-discharge current in an energy storage cell, the method comprising:
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applying, with a direct current (DC) voltage source, a constant test voltage to an energy storage cell without an external load connected thereto, the constant test voltage being less than an open-circuit voltage of the energy storage cell at an initial state of charge (SOC) of the energy storage cell; measuring a test current flowing between the DC voltage source and the energy storage cell until after the test current switches from a negative current to a positive current; and determining, with control circuitry operably coupled to a current measuring device, a self-discharge current of the energy storage cell by analyzing the measured test current, wherein the self-discharge current is indicative of a rate of internal discharge of charge stored by the energy storage cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for determining a self-discharge current of one or more energy storage cells, the system comprising:
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a direct current (DC) voltage source configured to provide a constant test voltage to one or more energy storage cells without an external load connected thereto, the constant test voltage selected to be less than an open circuit voltage of the one or more energy storage cells; a current measuring device operably coupled between the DC voltage source and the one or more energy storage cells and configured to measure a test current flowing between the DC voltage source and the one or more energy storage cells; control circuitry operably coupled to the current measuring device and configured to determine a self-discharge current of the one or more energy storage cells by analyzing the test current measured by the current measuring device, wherein the self-discharge current is indicative of a rate of internal discharge of charge stored by the energy storage cell; and a user interface configured to indicate at least one of the determined self-discharge current of the one or more energy storage cells and a health parameter of the one or more energy storage cells generated from the determined self-discharge current determined by the control circuitry. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of determining a self-discharge current of an energy storage cell, the method comprising:
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applying, with a direct current (DC) voltage source, a constant test voltage to an energy storage cell without an external load connected thereto, the constant test voltage selected to be less than an open-circuit voltage of an energy storage cell; measuring a test current flowing between the DC voltage source and the energy storage cell at least until after the test current switches from a negative current to a positive current flowing from the DC voltage source to the energy storage cell; and determining, with control circuitry operably coupled to a current measuring device, a self-discharge current of the energy storage cell by analyzing the measured test current wherein the self-discharge current is indicative of a rate of internal discharge of charge stored by the energy storage cell. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification