Methods of charging, equalizing, and controlling Li-based batteries
First Claim
1. Method of charging li-based batteries by constant current and then by constant voltage to minimum current, with following operations:
- a. Measurement of battery ohmic resistance b. Setting of battery overvoltage protection value, and c. Setting of minimum charging current depending on battery ohmic resistance and overvoltage protection.
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Abstract
Method of charging Li-based battery involves keeping the right balance among battery voltage, ohmic resistance, and charging current. Invention offers battery overvoltage protection value as the difference between the maximum voltage and the instantaneous open-circuit voltage. Overvoltage protection is supported when the minimum charging current is set as the ratio between difference in battery terminal voltage and instantaneous open-circuit voltage, and ohmic resistance. Method of equalizing Li-based battery is based on stabilization of cell voltage at end-of-charge by connecting in parallel to each cell, three series-connected Ni-based (i.e., NiCd or NiMH) cells, which serve as voltage stabilizers at end-of-charge. Individual lithium cell (flying cell) periodically connected to battery cells in process of charging and (or) discharging is used for equalizing of lithium battery cells. Method of controlling Li-based battery is based on measurement of battery ohmic and chemical resistances, and open-circuit voltage, with and without current interruption. Ohmic resistance controls the battery charging process and battery state-of-health. Nonstationary open-circuit voltage is used as an indicator (fuel gauge) of battery state-of-charge. Electrical double layer capacity provides information regarding electrode surface.
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Citations
26 Claims
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1. Method of charging li-based batteries by constant current and then by constant voltage to minimum current, with following operations:
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a. Measurement of battery ohmic resistance b. Setting of battery overvoltage protection value, and c. Setting of minimum charging current depending on battery ohmic resistance and overvoltage protection. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 24, 25, 26)
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- 11. Method of Li-based battery equalization in process of battery discharging, wherein individual lithium cell is periodically connected to battery lithium cell having minimum discharging voltage until voltage of two cells is getting equal to dynamically preselected voltage.
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12. Method of Li-based battery equalization in process of battery charging, wherein individual lithium cell is periodically connected to battery lithium cell having maximum charging voltage until voltage of two cells is getting equal to dynamically preselected voltage.
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13. Method of Li-based battery equalization, wherein three series-connected Ni-based batteries are connected in parallel to each Li-based cell, and Ni-based cells are part of charging device.
- 14. Method of hybridizing lithium battery and creating one hybrid power source, wherein each lithium cell permanently contains three series-connected Ni-based cells, wherein Li-based cell and Ni-based cells have parallel connection.
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16. Li-based battery control method that contains
a. Measurement of battery voltage b. Measurement of ohmic resistance c. Measurement of chemical resistance, and d. Measurement of open-circuit voltage.
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