System for scheduling battery charge and discharge in a reconfigurable battery
First Claim
1. A battery management system, comprising:
- a plurality of battery cells arranged in reconfigurable circuit paths;
a plurality of switches selectively interconnecting battery cells to one of charge terminals and discharge terminals; and
a scheduling module that;
receives an estimated load demand for the plurality of battery cells;
determines a subset of the plurality of battery cells needed to meet the load demand, wherein the number of battery cells in the determined subset is inversely correlated to a rate at which the plurality of battery cells recover voltage in a rest state; and
controls the plurality of switches to connect the subset of battery cells to the discharge terminals and to connect a remainder of the plurality of battery cells to the charge terminals.
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Abstract
Effective scheduling of battery charge and discharge activities, by making the most of battery characteristics, can extend the battery pack'"'"'s operation-time and lifetime. A system and method for scheduling battery activities is disclosed. This framework dynamically adapts battery activities to load demands and to the condition of individual battery cells, thereby extending the battery pack'"'"'s operation-time and making them robust to anomalous voltage imbalances. The scheduling framework includes two components. An adaptive filter estimates the upcoming load demand. Based on the estimated load demand, a scheduler can determine the number of parallel-connected battery cells to be discharged. The scheduler also effectively partitions the battery cells in a pack, allowing the battery cells to be simultaneously charged and discharged in coordination with a reconfigurable battery circuit.
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Citations
16 Claims
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1. A battery management system, comprising:
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a plurality of battery cells arranged in reconfigurable circuit paths; a plurality of switches selectively interconnecting battery cells to one of charge terminals and discharge terminals; and a scheduling module that; receives an estimated load demand for the plurality of battery cells; determines a subset of the plurality of battery cells needed to meet the load demand, wherein the number of battery cells in the determined subset is inversely correlated to a rate at which the plurality of battery cells recover voltage in a rest state; and controls the plurality of switches to connect the subset of battery cells to the discharge terminals and to connect a remainder of the plurality of battery cells to the charge terminals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for scheduling battery cells for charging and discharging in a reconfigurable battery system, comprising:
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monitoring state of charge for each of a plurality of battery cells; partitioning the plurality of battery cells into a group of cells eligible for discharging and another group of cells eligible for charging in accordance with the state of charge of the battery cells; selecting a subset of battery cells from the group of cells eligible for discharging and discharging the battery cells in the subset, where a number of battery cells in the subset of battery cells is inversely correlated to a rate at which the plurality of battery cells recover voltage in a rest state; selecting a scheduling method based on the number of battery cells in the subset; charging one or more battery cells in the group of cells eligible for charging while one or more battery cells in the group of cells eligible for discharging are being discharged; and reassigning the plurality of battery cells into either the group of cells eligible for discharging or the group of cells eligible for charging after the step of charging one or more battery cells. - View Dependent Claims (11, 12, 13, 14)
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15. A method for scheduling battery cells for charging and discharging in a reconfigurable battery system, comprising:
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monitoring state of charge for each of a plurality of battery cells; partitioning the plurality of battery cells into a group of cells eligible for discharging and another group of cells eligible for charging in accordance with the state of charge of the battery cells; determining state of charge for each of the battery cells in the group of cells eligible for discharging, determining a median state of charge for the battery cells in the group of cells eligible for discharging, and computing a period of time for discharging as a function of the median, charging one or more battery cells in the group of cells eligible for charging while one or more battery cells in the group of cells eligible for discharging are being discharged; discharging battery cells in the group of cells eligible for discharging for the computed period of time while bypassing a given battery cell in the group of cells eligible for discharging having the lowest state of charge in the group of cells eligible for discharging; and reassigning the plurality of battery cells into either the group of cells eligible for discharging or the group of cells eligible for charging after the step of charging one or more battery cells.
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16. A method for scheduling battery cells for charging and discharging in a reconfigurable battery system, comprising:
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monitoring state of charge for each of a plurality of battery cells; partitioning the plurality of battery cells into a group of cells eligible for discharging and another group of cells eligible for charging in accordance with the state of charge of the battery cells; determining state of charge for each of the battery cells in the group of cells eligible for discharging, determining a median state of charge for the battery cells in the group of cells eligible for discharging, charging one or more battery cells in the group of cells eligible for charging while one or more battery cells in the group of cells eligible for discharging are being discharged; discharging battery cells in the group of cells eligible for discharging by an amount equal to the median while bypassing a given battery cell in the group of cells eligible for discharging having the lowest state of charge in the group of cells eligible for discharging; and reassigning the plurality of battery cells into either the group of cells eligible for discharging or the group of cells eligible for charging after the step of charging one or more battery cells.
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Specification