Performing active interrogation of battery packs in situ to obtain precise SOC and SOH estimates
First Claim
1. A method comprising:
- (a) controlling a plurality of Energy Storage Systems (ESSs) to supply power onto an electrical power bus and to receive power from the electrical power bus, wherein each of the ESSs is coupled to one of a plurality of switching power converters, and wherein each of the switching power converters is coupled to the electrical power bus;
(b) generating a pre-determined signal using a first switching power converter, wherein charge flows from a first ESS onto the electrical power bus via the first switching power converter, wherein charge flows from the electrical power bus onto a second ESS via a second switching power converter, wherein current is sourced or sinked between the first and second ESSs, and wherein the pre-determined signal is masked from a load during (a) and (b);
(c) measuring a response signal output by the first ESS as a result of generating the pre-determined signal in (b); and
(d) determining a value indicative of a characteristic of the first ESS using the pre-determined signal and the response signal.
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Accused Products
Abstract
A characteristic, such as State Of Health (SOH) or State Of Charge (SOC), is estimated for an Energy Storage System (ESS) by supplying a pre-determined signal to the ESS, measuring a response signal output by the ESS, and obtaining an impedance spectrum of the ESS. In one example, the ESS is one of several electrochemical battery packs of an electric vehicle. The pre-determined signal is a current signal generated by a switching power converter that transfers charge from the battery pack to other battery packs or transfers charge from the other battery packs onto the battery pack. The pre-determined signal is generated without disrupting any load supplied by the battery packs. The battery pack outputs a voltage signal in response to receiving the pre-determined current signal. A processor obtains an impedance spectrum using the current and voltage signals, and thereby obtains an SOH and SOC estimate of the battery.
34 Citations
20 Claims
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1. A method comprising:
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(a) controlling a plurality of Energy Storage Systems (ESSs) to supply power onto an electrical power bus and to receive power from the electrical power bus, wherein each of the ESSs is coupled to one of a plurality of switching power converters, and wherein each of the switching power converters is coupled to the electrical power bus; (b) generating a pre-determined signal using a first switching power converter, wherein charge flows from a first ESS onto the electrical power bus via the first switching power converter, wherein charge flows from the electrical power bus onto a second ESS via a second switching power converter, wherein current is sourced or sinked between the first and second ESSs, and wherein the pre-determined signal is masked from a load during (a) and (b); (c) measuring a response signal output by the first ESS as a result of generating the pre-determined signal in (b); and (d) determining a value indicative of a characteristic of the first ESS using the pre-determined signal and the response signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system comprising:
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an electrical power bus that supplies a load; a plurality of Energy Storage Systems (ESSs), wherein each of the ESSs is configured to supply energy onto the electrical power bus and to receive energy from the electrical power bus; and a plurality of controllers, wherein each of the controllers is coupled to one of the ESSs and is also coupled to the electrical power bus, wherein each of the controllers comprises; a switching power converter, wherein a pre-determined signal is generated using the switching power converter by transferring energy from one of the ESSs to the electrical power bus via the switching power converter, wherein energy is transferred from the electrical power bus to another of the ESSs, wherein current is sourced or sinked between at least two of the ESSs, and wherein power supplied to the load does not substantially change in response to generating the pre-determined signal; a sense circuit that measures a response signal output by the one of the ESSs as a result of the pre-determined signal that is generated; and a processor that determines a value indicative of a characteristic of the one of the ESSs using the pre-determined signal and the response signal. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A system comprising:
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a plurality of Energy Storage Systems (ESSs) that supply current to an electrical load, wherein each of the ESSs is coupled to each of the other ESSs, wherein charge is transferable between the ESSs; means for determining a value indicative of a characteristic of one of the ESSs without perturbing current supplied to the electrical load, wherein the means;
(a) causes a pre-determined signal to be generated by operating a power converter such that available charge in one ESS increases and available charge in another ESS decreases without substantially impacting the current supplied to the electrical load and such that current is sourced or sinked between at least two of the ESSs, (b) measures a response signal output by the one of the ESSs to obtain a measured response signal, (c) processes the measured response signal to obtain an estimate of an impedance spectrum of the one of the ESSs, and (d) determines the characteristic using the estimate of the impedance spectrum, and wherein the characteristic is selected from the group consisting of;
a State Of Health (SOH), and a State Of Charge (SOC). - View Dependent Claims (20)
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Specification