Method for balancing cells in batteries
First Claim
1. A method for balancing two adjacent battery cells arranged in series, comprising the steps of:
- a) closing a first isolated switch of a first battery cell from which energy is to be transferred to thereby transfer energy from that battery to an energy storage device that is in electrical communication with a node connecting a negative terminal of a second battery cell to a positive terminal of the first battery cell, thereby charging the energy storage device; and
thereafterb) simultaneously opening the first isolated switch and closing a second isolated switch, the second isolated switch thereby causing energy to be transferred from the energy storage device to the second cell, whereby the second battery cell will have a voltage at least closer to that of the first battery cell.
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Abstract
Adjacent battery cells connected in devices are balanced by closing a first circuit to charge an energy storage device from a first battery cell and thereafter simultaneously opening the first isolated switch and closing a second isolated switch to cause the energy storage device to charge a second battery cell. A circuit includes an isolated switch that operates simultaneously to balance battery cells connected in series, and a battery system balances battery modules connected in series, the battery module including battery cells connected in series. The battery cells and modules can be balanced by hierarchical balancing of modules of the battery pack and component cells of the modules.
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Citations
26 Claims
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1. A method for balancing two adjacent battery cells arranged in series, comprising the steps of:
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a) closing a first isolated switch of a first battery cell from which energy is to be transferred to thereby transfer energy from that battery to an energy storage device that is in electrical communication with a node connecting a negative terminal of a second battery cell to a positive terminal of the first battery cell, thereby charging the energy storage device; and
thereafterb) simultaneously opening the first isolated switch and closing a second isolated switch, the second isolated switch thereby causing energy to be transferred from the energy storage device to the second cell, whereby the second battery cell will have a voltage at least closer to that of the first battery cell. - View Dependent Claims (2, 3, 4, 5)
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6. A battery system comprising:
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a) a plurality of battery modules, each module including; i) a string of battery cells, and ii) a plurality of cell balancing circuits, each of the plurality of cell balancing circuits including a pair of isolated switches and a control unit configured to operate the pair of switches to transfer energy between two adjacent cells in the string of battery cells; and b) a plurality of module balancing circuits, each of the module balancing circuits including a pair of isolated switches and a control unit configured to operate the pair of switches to transfer energy between two adjacent battery modules. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of hierarchical balancing of a plurality of battery modules, comprising:
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a) balancing cells of a first battery module; b) balancing cells of a second battery module; and c) balancing the modules, including the steps of; closing a first circuit of the first battery module from which energy is to be transferred to thereby transfer energy from that battery module to an energy storage device that is in electrical communication with a node connecting a negative terminal of the second battery module to a positive terminal of the first battery module, thereby charging the energy storage device; and
thereaftersimultaneously opening the first circuit and closing a second circuit, the second circuit thereby causing energy to be transferred from the energy storage device to the second battery module, whereby the second battery module will have a voltage at least closer to that of the first battery module.
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16. A method for balancing battery modules, comprising the steps of:
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a) closing a first circuit of a first battery module from which energy is to be transferred to thereby transfer energy from that battery module to an energy storage device that is in electrical communication with a node connecting a negative terminal of a second battery module to a positive terminal of the first battery module, thereby charging the energy storage device; and
thereafterb) simultaneously opening the first circuit and closing a second circuit, the second circuit thereby causing energy to be transferred from the energy storage device to the second battery module, whereby the second battery module will have a voltage at least closer to that of the first battery module. - View Dependent Claims (17, 18, 19)
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20. A method of balancing battery cells, comprising:
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detecting an energy imbalance between a first battery module and a second battery module, each of the modules including a plurality of battery cells; transferring energy from the first battery module to the second battery module such that the second battery module will have a voltage at least closer to that of the first battery module; detecting an energy imbalance between a first battery cell and a second battery cell of the second battery module upon distributing the energy from the first module among the battery cells of the second module; and transferring energy from the first battery cell to the second battery cell such that the second battery cell will have a voltage at least closer to that of the first battery cell. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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Specification