WO2018057532A1

WO2018057532A1 - Battery charge transfer modeling including time-aligned, filter-response-matched voltage and current measurement

Info

Publication number: WO2018057532A1
Application number: PCT/US2017/052326
Authority: WO
Original assignee: Cougeller Research Llc
Priority date: 2016-09-23
Filing date: 2017-09-19
Publication date: 2018-03-29

Abstract

A system includes a cell voltage measurement device and a cell current measurement device configured to measure the voltage and cell current of battery cells within a battery pack. The cell voltage measurement and cell current measurement devices share one or more filter characteristics, such that the filters used for voltage and current measurements produce similar responses. The voltage and current measurements may correspond to a similar or identical period of measurement. Charge transferred by the cell or battery string during a measurement period may be measured or calculated, for example by a coulomb counter. One or more charge transfer models for a cell or battery pack may be updated using the voltage, current, and charge measurements. Contiguous measurements of current in a string of battery cells may be made, to correspond to cell measurements that cycle, via a multiplexor, through several cells within the string.

Description

TITLE: BATTERY CHARGE TRANSFER MODELING INCLUDING TIME-ALIGNED,

FILTER-RESPONSE-MATCHED VOLTAGE AND CURRENT MEASUREMENT

BACKGROUND

Technical Field

[0001] The disclosed embodiments relate to battery management systems and charge transfer modeling for batteries and battery packs configured to provide electrical power to a variety of devices, for example electric and hybrid vehicles or portable electronic devices. More specifically, the disclosed embodiments relate to charge transfer modeling using time-aligned voltage and current samples and filter-response-matched sampling.

Description of the Related Art

[0002] Battery management systems serve numerous functions related to rechargeable battery systems, including monitoring states of a battery pack or battery cells including state of charge ("SOC") and state of health ("SOH"), protecting the operational integrity of a battery, reporting and/or preventing abnormal operating conditions in a battery, monitoring an environment about a battery, etc.

[0003] A state of charge of a battery or battery pack is a measure of how much charge is left in the battery pack. An SOC may typically be expressed as a percentage 0-100% representing how much charge remains in the battery compared to the full capacity of the battery or pack. SOC may also be expressed in other ways, for example as a unit of charge (Ah).

[0004] A state of health of a battery or battery pack is a value used to characterize the performance or health of a battery or pack compared to its ideal conditions. For example, many rechargeable battery packs naturally lose capacity over time. An example SOH of a battery pack may represent the present maximum capacity of a battery as a percentage of the original or specified capacity of the battery. A typical SOH may be calculated using any combination of various conditions of a battery, including number of charging cycles completed; measured, modeled, or estimated internal resistance of the battery; measured, modeled, or estimated self- discharge rates of the battery; cell balance information; or measured, modeled, or estimated present capacity or voltage of the battery, among others.

[0005] Battery management systems may use one or more charge transfer models that represent expected parameters of a battery or battery pack during one or more of a discharge cycle, a charging cycle, and an idle state of the battery. In particular, one or more charge transfer ("Q"), voltage ("V"), and current ("i") may be stored as part of a battery charge transfer model, and those values may be associated in the model with various states of the battery or battery pack, including SOC and SOH.

[0006] Battery management systems typically use separate devices to measure or calculate voltage, current, and Q of a battery. For example, Q may typically be measured or calculated by integrating the measured current values over a period of time. These measurement and calculation devices typically exhibit disparate filter response characteristics. For example, various filters will typically exhibit different magnitude and phase responses to the same input signal. Further, the measurement and calculation devices and are often activated to measure the parameters at different times from each other, necessitating a large amount of estimation in order to calculate a charge transfer model for any particular condition, such as an SOC, SOH, or elapsed time of a charge or discharge cycle.

[0007] A battery or battery management system can include one or more devices for measuring voltage and current with matching filter responses. Some systems may include similar means for measuring or calculating charge transfer. These measurements may be time-aligned with each other for increased accuracy of battery modeling.

SUMMARY [0008] A system for modeling charge transfer of a battery includes a cell voltage measurement device configured to measure a voltage of a battery cell within a battery pack. For example, the cell voltage measurement device can be configured to measure a voltage of a first battery cell of a battery pack electrically coupled to the cell voltage measurement device. The system also includes a cell current measurement device configured to determine a cell current across the battery cell and/or a string of battery cells including the battery cell. For example, the cell current measurement device can be configured to determine a cell current representing a current across a second battery cell of the battery pack. The cell voltage measurement and cell current measurement devices can share one or more filter characteristics, such that the filters used for voltage and current measurements produce similar responses.

[0009] In addition, the cell voltage measurement device and the cell current measurement device can be configured to measure the respective cells of the battery pack at the same time. For example, a clock can be configured to generate a clock signal having clock edges, and the voltage of a first battery cell and the cell current of a second battery cell can be measured at the same time by measuring the cell voltage responsive to a clock edge and measuring the cell current responsive to the same clock edge. As another example, the voltage of a first battery cell and the cell current of a second battery cell can be measured at the same time by measuring the voltage during a first time interval and the cell current during a second time interval, where the second time interval at least partially overlaps with the first time interval. As another example, the cell voltage measurement circuit can be configured to measure a voltage of the second battery cell as it measures the voltage of a first battery cell. The voltage and current measurements may correspond to a similar or identical period of measurement.

[0010] Charge transferred by the cell or battery string during a measurement period may be measured or calculated, for example by an electron-counting device, electrically coupled to the cell or battery string, which can be configured to count electrons flowing in or out of the battery pack, for example a coulomb counter. One or more charge transfer models for a cell or battery pack may be updated using the voltage, current, and charge measurements. Contiguous measurements of current in a string of battery cells may be made, to correspond to cell measurements that cycle, via a multiplexor, through several cells within the string. A charge transfer model for a battery pack may include the sum of charge transfer models for a plurality of cells within the battery pack. A battery management device can be configured to provide output representing the remaining capability of a battery pack using, for example, the voltage of a first battery cell, the current across a second battery cell, and/or the voltage of the second battery cell.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 shows a high-level block diagram of an example battery monitoring system according to some embodiments.

[0012] FIG. 2 shows a block diagram of an example battery monitoring module and associated components, according to some embodiments.

[0013] FIG. 3 shows a component block diagram of a cell monitoring module application- specific integrated circuit ("ASIC") and pack monitor ASICs, according to some embodiments.

[0014] FIG. 4A shows example sampling periods of an example current waveform, according to some embodiments.

[0015] FIG. 4B shows example sampling periods of an example voltage waveform, according to some embodiments.

[0016] FIG. 5 is a flowchart of an example process for monitoring parameters of a battery cell and updating a cell charge transfer model, according to some embodiments.

[0017] FIG. 6 is a flowchart of an example process for monitoring parameters of several cells and updating a pack charge transfer model, according to some embodiments. [0018] FIG. 7 illustrates a computer system that may be configured to include or execute any or all of the embodiments described herein.

[0019] Some occurrences of the term "battery" and its synonyms as used in this specification may refer to a single battery cell, a string or group of battery cells, a battery pack, and/or any battery system including multiple battery cells, depending on the context, as one having ordinary skill in the art will understand.

DETAILED DESCRIPTION OF EMBODIMENTS

[0020] Various embodiments of a battery monitoring and charge transfer modeling system are disclosed. Various embodiments and methods of monitoring battery voltage, current, and charge transfer are also disclosed.

[0021] System 100 of FIG. 1 shows a high-level block diagram of an example battery monitoring system according to some embodiments. A battery management module ("BMM") 110 may be responsible for a variety of tasks related to battery monitoring and management, for example: primary pack current and Q measurements or calculations; pack voltage measurements or calculations; curation of one or more battery charge transfer models; computation for battery management controls and algorithms, monitoring and activation of battery preservation and safety modes including thermal monitoring and management, liquid or gas detection, high- voltage isolation monitoring, high-voltage interlock monitoring, contactor control, etc.; communication of battery states and abnormal operation; and managing a network interface for communication between a battery and other devices. A BMM may be configured to provide output representing the remaining capability of a battery pack using, for example, the voltage of a first battery cell, the current across a second battery cell, and/or the voltage of the second battery cell.

[0022] It should be noted that the devices, apparatuses, methods and/or modules described herein can be implemented by hardware including, but not limited to, a circuit or circuits, including an interconnection of electrical components (e.g. batteries, resistors, inductors, capacitors, switches, transistors) consisting of electrical elements (e.g. voltage sources, current sources, resistances, inductances, capacitances), an ASIC, programmable logic arrays and/or other hardware devices. In addition, one or more software and/or firmware programs running on a computer processor can likewise implement some or all of the example devices, apparatuses, methods and/or modules described herein, either in whole or in part. [0023] BMM 110 according to some embodiments may be connected to a high -voltage distribution module ("HVDM") 120. HVDM 120 may be responsible for one or more of: primary and auxiliary power transfer contactors, precharge relays, precharge resistor(s), and primary and auxiliary power transfer fuses, among others, as well as other functions related to power distribution, as one having ordinary skill in the art will understand.

[0024] BMM 110 or HVDM 120 according to some embodiments may be connected to or in communication with one or more sensors 140. For example, sensor 140 may detect one or more temperatures of a battery, one or more temperatures of an environment around a battery, one or more temperatures of a coolant or quenching material, liquid within a battery such as in the case of an electrolyte leak or battery submersion, or any number of other sensors as one having ordinary skill in the art will understand.

[0025] BMM 110 or HVDM 120 according to some embodiments may further be connected to one or more cell monitoring modules ("CMMs") 130a-130n. A CMM 130 according to some embodiments may correspond to one or more battery cells. A CMM 130 may be responsible for obtaining primary cell voltage measurements, various battery temperature measurements, controls related to cell balancing, or cell over-voltage detection, as well as other functions as one having ordinary sill in the art will understand.

[0026] BMM 110 according to some embodiments may read from or store to charge transfer models 150. As described above, charge transfer models for a battery may represent expected parameters of a battery or battery pack during one or more of a discharge cycle, a charging cycle, and an idle state of the battery. In particular, one or more charge transfer ("Q"), voltage ("V"), and current ("i") may be stored as part of a battery charge transfer model, and those values may be associated in the model with various states of the battery or battery pack, including SOC and SOH.

[0027] According to some embodiments, charge transfer models 150 may be stored remotely from BMM 110, for example in a database of a vehicle or other device within which BMM 110 is deployed, or a remote database. Alternatively or additionally, charge transfer models 150 according to some embodiments may be stored at BMM 110, for example in a memory located within BMM 110.

[0028] System 200 of FIG. 2 shows a block diagram of an example battery monitoring module and associated components, according to some embodiments. Several submodules of an example BMM 210 are shown at FIG. 2 and discussed in detail below.

[0029] BMM 210 according to some embodiments may be connected to a high -voltage distribution module ("HVDM") 220. HVDM 220 may be responsible for one or more of: primary and auxiliary power transfer contactors, precharge relays, precharge resistor(s), and primary and auxiliary power transfer fuses, among others, as well as other functions related to power distribution, as one having ordinary skill in the art will understand.

[0030] HVDM 220 according to some embodiments may further be connected to a high- side/low-side ("HS/LS") switch 284 of BMM 210. HVDM 220 or HS/LS switch 284 may further be connected to a contactor safety logic ASIC 286 of BMM 210, which in some embodiments may be configured to monitor safe contactor configurations and prevent unsafe contactor connections via HVDM 220.

[0031] BMM 210 or HVDM 220 according to some embodiments may further be connected to one or more cell monitoring modules ("CMMs") 230a-230n. A CMM 230 according to some embodiments may correspond to one or more battery cells. A CMM 230 may be responsible for obtaining primary cell voltage measurements, various battery temperature measurements, controls related to cell balancing, or cell over-voltage detection, as well as other functions as one having ordinary sill in the art will understand.

[0032] HVDM 220 or any of CMMs 230a-230n may further be connected to current transducers 250a and 250b via transmission loop 222, according to some embodiments. Current transducers 250a and 250b according to some embodiments may be any suitable current sensor, as one having ordinary skill in the art will understand. For example, a current transducer 250a or 250b may include a sensor configured to detect an electrical current and generate a proportional signal in response to the presence of electrical current. In some example embodiments, one or more of sensors 250a and 250b may include a current shunting device. In some embodiments, one or more of sensors 250a and 250b may include an electron-counting device, electrically coupled to the cell or battery string, which can be configured to count electrons flowing in or out of the battery pack, a coulomb counter or other similar device.

[0033] Current transducers 250a and 250b according to some embodiments may be connected to pack monitor ASICs 260a and 260b. Pack monitor ASICs 260a and 260b according to some embodiments may include one or more analog-to-digital converters ("ADCs") for converting an analog signal from a sensor 250 into a digital signal suitable for calculation and communication of current and/or Q values. In other embodiments, only a single pack monitor ASIC 260 may be used. Pack monitor ASICs 260a and 260b according to some embodiments may be connected to CMMs 230a-230n via bus 262.

[0034] An example BMM 210 according to some embodiments may include a computing section 240 including one or more computing modules. For example, computing section 240 may include an algorithmic microprocessor unit ("MPU") 242 for calculating various algorithms relevant to battery management, for example state of charge, state of health, cell or pack V, I, or Q, or other operational computations. [0035] An example computing section 240 according to some embodiments may further include a safety microcontroller ("MCU") 244 module for calculating parameters related to battery safety. For example, thermal parameters, liquid detection parameters, over-voltage or overcharge parameters, battery cooling calculations, and other safety-related operational parameters as one having ordinary skill in the art will understand.

[0036] One or more of a pack monitor 260 or any module of compute block 240 may further be connected to one or more communication monitoring ASICs 270a or 270b. A communication monitoring ASIC 270 according to some example embodiments may monitor and control communications including parameter measurement and calculation reporting, SOC or SOH information, safety parameters or reporting, or other operational communications.

[0037] An example BMM 210 may include a power management unit 292 for helping govern power distribution to digital components of BMM 210. Power management unit 292 may be any such controller suitable for the functions required of and devices present in a particular BMM 210, as will be apparent to one having ordinary skill in the art.

[0038] Various example embodiments may include means for BMM 210 to communicate with other devices, for example a central computer of a vehicle device within which BMM 210 is employed, a remote monitoring or reporting system, or a database. Network interface 294 may enable communication between BMM 210 and other devices. Such communications may be further enabled by general purpose input/output device 296, according to some embodiments.

[0039] An example BMM 210 may further include a high-voltage isolation monitor 282. For example, a BMM 210 employed in an electric or hybrid vehicle may monitor an insulation condition meant to separate the high-voltage of the vehicle's battery pack from the chassis of the vehicle, ensuring proper operation. Detection of a loss of insulation event may trigger various protocols to limit the likelihood of damage to the vehicle, its operator or occupants, or other systems.

[0040] System 300 of FIG. 3 shows a component block diagram of a cell monitoring module ASIC and pack monitor ASICs, according to some embodiments. According to some embodiments, a CMM may include one or more primary cell monitor ASICs. A primary cell monitor ASIC 310 (also called a CMM ASIC) according to some embodiments may include one or more ADCs 330a-330c.

[0041] A primary cell monitor ASIC 330a according to some embodiments, may include a conditioning filter 332a, a decimation filter 334a, and a sigma-delta modulator 336a. Sigma- delta modulator 336a according to some embodiments may be configured to convert an analog signal to a digital signal. Such conversion may be desirable, for example, to simplify filtering, enable transmission of the signal across a communication bus, or to simplify calculations including the signaled measurement.

[0042] Primary cell monitor ASIC 330a according to some embodiments further includes a conditioning filter 332a. A conditioning filter may include any combination of a low-pass filtering function, a sine function, an averaging filter, or other filtering functions as will be apparent to one having ordinary skill in the art.

[0043] Primary cell monitor ASIC 330a according to some embodiments further includes a decimation filter 334a. Decimation filter 334a may serve to filter the input signal to a manageable data rate, for example by applying no-loss filtering in accordance with the Nyquist theorem, or other filtering functions as will be apparent to one having ordinary skill in the art of signal processing.

[0044] According to some embodiments, the hardware of additional ADCs, such as ADCs 330b and 330c, may be identical hardware or hardware that is similar in frequency response to ADC 330a. For example, conditioning filters 332b and 332c may be identical to conditioning filter 332a as described above; decimation filters 334b and 224c may be identical to decimation filter 334a as described above; and sigma-delta modulators 336b and 336c may be identical to sigma- delta modulator 336a as described above. According to some embodiments, matching filter characteristics, for example by selecting filters with similar magnitude or phase responses across all ADCs in the BMM may increase accuracy and compatibility of measurement within the BMM.

[0045] Primary cell monitors ASIC 310 according to some embodiments may include one or more multiplexors 320. In the example embodiment of FIG. 3, primary cell monitor ASIC 310 includes three multiplexors 320a-320c, each corresponding to five battery cells 340. In the example embodiment of FIG. 3, multiplexor 320c corresponds to cells 340a-340e, multiplexor 320b corresponds to cells 340f-340j, and multiplexor 320c corresponds to cells 340k-340o.

[0046] Cells 340 of system 300 may according to some embodiments be connected in series with current transducer or shunt devices 350a and 350b. Current transducers 350a and 350b according to some embodiments may be any suitable current sensor, as one having ordinary skill in the art will understand. For example, a current transducer 350a or 350b may include a sensor configured to detect an electrical current and generate a proportional signal in response to the presence of electrical current. In some example embodiments, one or more of sensors 350a and 350b may include a current shunting device. In some embodiments, one or more of sensors 350a and 350b may include a coulomb counter or other similar device.

[0047] Sensors 350a and 350b according to some embodiments may be connected to amplifiers 368a-368d of pack monitor ASICs 360a and 360b. Amplifiers 368a-368d according to some embodiments may be connected to ADCs 361a-361d, respectively. In some embodiments, a single pack monitor ASIC 360 may be used.

[0048] According to some embodiments, the hardware of additional ADCs, such as ADCs 361a- 361d, may be identical hardware or hardware that is similar in frequency response to ADC 330a. For example, conditioning filters 362-362d may be identical to conditioning filter 332a as described above; decimation filters 364a-364d may be identical to decimation filter 334a as described above; and sigma-delta modulators 366a-366d may be identical to sigma-delta modulator 336a as described above. According to some embodiments, matching filter characteristics, for example by selecting filters with similar magnitude or phase responses across all ADCs in the BMM may increase accuracy and compatibility of measurement within the BMM.

[0049] In one example embodiment of a system for monitoring and modeling charge transfer of a battery, a battery pack includes 240 cells arranged in a series string. In this example embodiment, each CMM ASIC (or primary cell monitor ASIC) contains three ADC assemblies. Each ADC assembly is multiplexed to five cells, for a total of 15 cells serviced by each CMM ASIC. In this example embodiment, each CMM contains two CMM ASICs, for a total of 30 cells served by each CMM. The 240-cell pack, then, requires 8 CMMs, 16 CMM ASICs, and 48 ADC assemblies. The example pack also contains one or two pack monitor ASICs, each containing two ADC assemblies identical to the ADC assemblies of the primary cell monitor ASICs.

[0050] In the example system of the previous paragraph, a coulomb counter may be configured to find Q of the battery pack string in contiguous 10ms periods. In the example, each multiplexor (one for each ADC assembly) cycles every 2ms, selecting the next of its 5 connected battery cells and sampling its voltage. Also every 2ms, the matched pack monitor ASICs sample the current of the battery pack string. This configuration of the example system results in a complete set of frequency-response-matched, time-aligned data, including Q, V, and i for the entire 240-cell pack, every 10ms.

[0051] FIG. 4 A shows example sampling periods of an example current waveform 410, according to some embodiments. According to some embodiments, waveform 410 may represent a measured current waveform of a battery cell or string of battery cells.

[0052] According to some embodiments, Q period(s) 420 represent periods of monitoring of charge transfer to or from the battery cell or string of cells represented by waveform 410. For example, according to some embodiments, a coulomb counter may detect or calculate charge transfer, for example by integrating measured current over the Q measurement period. According to some embodiments, Q is measured in contiguous blocks of time as represented by the three example Q periods shown at FIG. 4A.

[0053] According to some embodiments, one or more current values may be measured or calculated at the blocks represented and marked current samples 430 at FIG. 4 A. As one example, a high-frequency sampling device may sample a current waveform for a period of time (500μ8 in one example embodiment) and average the sample values to reduce sampling error. In other embodiments, a current sample 430 may represent a current measurement at a single moment in time.

[0054] FIG. 4B shows example sampling periods of an example voltage waveform, according to some embodiments. One or more voltage values may be measured or calculated at the blocks represented and marked voltage samples(s) 440 at FIG. 4B. According to some embodiments, voltage sample windows 440 of FIG. 4B may be time-aligned with respective current samples 430 of FIG. 4 A. As one example, a high-frequency sampling device may sample a voltage waveform for a period of time (500μ8 in one example embodiment) and average the sample values to reduce sampling error.

[0055] According to some embodiments, the contiguous Q sampling periods 420 of FIG. 4 A and synchronized sampling periods 430 of FIG. 4 A and 440 of FIG. 4B may enable time-aligned measurements of Q, V, and i within a small margin of error— microseconds in some example embodiments.

[0056] FIG. 5 is a flowchart of an example process 500 for monitoring parameters of a battery cell and updating a cell charge transfer model, according to some embodiments. Step 510 represents the beginning of a Q counting window. For example, a Q counting window may be understood as a Q period 420 as described above with reference to FIG. 4A.

[0057] At step 520, the voltage of a cell is measured. For example, a cell voltage may be measured at a primary cell ASIC during a sample window such as a sample window 440 as described with reference to FIG. 4B.

[0058] At step 530, the current of the cell is measured. For example, a cell or string current may be measured at a pack monitor ASIC during a current sample window such as a current sample window 430 as described with reference to FIG. 4 A.

[0059] At step 540, the Q counting window is closed. In some embodiments, one or both of the cell voltage sample window of step 520 and cell current sample window of step 530 may be time-aligned with the Q counting window. For example, one or both of the cell voltage sample window of step 520 and cell current sample window of step 530 may begin at the same time that the Q counting window begins or end at the same time that the Q counting window ends. For example, a clock can be configured to generate a clock signal having clock edges, and the voltage of a first battery cell and the cell current of a second battery cell can be measured at the same time by measuring the cell voltage responsive to a clock edge and measuring the cell current responsive to the same clock edge. As another example, the voltage of a first battery cell and the cell current of a second battery cell can be measured at the same time by measuring the voltage during a first time interval and the cell current during a second time interval, where the second time interval at least partially overlaps with the first time interval. As another example, the cell voltage measurement circuit can be configured to measure a voltage of the second battery cell as it measures the voltage of a first battery cell.

[0060] At step 550, the system determines whether a cell model needs updating. For example, a current transfer model of the sampled cell may be updated using the Q, V, and i measurements sampled during process 500. In some embodiments, a system or BMM may be configured to update a cell model only under certain circumstances. For example, various operating parameters of a cell or pack, a certain period of elapsed time since the last update, a threshold difference between an expected value based on the present model and a value measured or calculated during process 500, or other conditions may be required to enable model updating.

[0061] If a cell model update is not enabled at step 550, the process reverts back to step 510. When conditions allow for enablement of a cell model update, the process proceeds to step 560.

[0062] At step 560, if updating is determined necessary according to the system or BMM configuration, one or more charge transfer models associated with the sampled battery cell may be updated using one or more of the measured or calculated Q, V, and i information obtained during process 500.

[0063] FIG. 6 is a flowchart of an example process 600 for monitoring parameters of several cells and updating a pack charge transfer model, according to some embodiments. At step 610, a multiplexor selects a cell. According to some embodiments, a multiplexor configuration similar to FIG. 3 may be used, in part, to implement step 610.

[0064] Step 620 represents the beginning of a Q counting window. For example, a Q counting window may be understood as a Q period 420 as described above with reference to FIG. 4A.

[0065] At step 630, the voltage of the selected cell is measured. For example, a cell voltage may be measured at a primary cell ASIC during a sample window such as a sample window 440 as described with reference to FIG. 4B.

[0066] At step 640, the current of the selected cell is measured. For example, a cell or string current may be measured at a pack monitor ASIC during a current sample window such as a current sample window 430 as described with reference to FIG. 4 A.

[0067] At step 650, the Q counting window is closed. In some embodiments, one or both of the cell voltage sample window of step 630 and cell current sample window of step 640 may be time-aligned with the Q counting window. For example, one or both of the cell voltage sample window of step 630 and cell current sample window 640 of step may begin at the same time that the Q counting window begins or end at the same time that the Q counting window ends.

[0068] At step 660, one or more charge transfer models associated with the selected cell may be updated using one or more of the measured or calculated Q, V, and i information obtained during process 600.

[0069] At step 670, a determination is made whether fresh data exists for a full "cycle" of multiplexed cells. For example, in the example embodiment of FIG. 3, a multiplexor is connected to five cells. In such an example, five iterations of steps 610-650 may be required before control will pass to step 680. If a negative determination is made at step 670, process 600 reverts back to step 610.

[0070] At step 680, the system determined whether a pack model needs updating. For example, a current transfer model of a battery pack including cells sampled during process 600 may be updated using the Q, V, and i measurements sampled for various cells during process 600. In some embodiments, a system or BMM may be configured to update a pack model only under certain circumstances. For example, various operating parameters of a cell or pack, a certain period of elapsed time since the last update, a threshold difference between an expected value based on the present model and a value measured or calculated during process 600, or other conditions may be required to enable model updating.

[0071] If a pack model update is not enabled at step 680, the process may revert back to step 610. In other embodiments, process 600 may wait at step 680 until conditions permit updating a pack cell transfer model. When conditions allow for enablement of a pack model update, the process may proceed to step 690.

[0072] At step 690, if updating is determined necessary according to the system or BMM configuration, one or more charge transfer models associated with a battery pack of sampled cells may be updated using one or more of the measured or calculated Q, V, and i information obtained during process 600.

[0073] FIG. 7 illustrates a computer system that may be configured to include or execute any or all of the embodiments described herein. In different embodiments, computer system 700 may be any of various types of devices, including, but not limited to, a personal computer system, desktop computer, laptop, notebook, tablet, slate, pad, or netbook computer, cell phone, smartphone, PDA, portable media device, mainframe computer system, handheld computer, workstation, network computer, a camera or video camera, a set top box, a mobile device, a consumer device, video game console, handheld video game device, application server, storage device, a television, a video recording device, a peripheral device such as a switch, modem, router, or in general any type of computing or electronic device.

[0074] Various embodiments of a system for modeling charge transfer of a battery may be executed in one or more computer systems 700, which may interact with various other devices. Note that any component, action, or functionality described above with respect to FIGs. 1 through 8 may be implemented on one or more computers configured as computer system 700 of FIG. 7, according to various embodiments. In the illustrated embodiment, computer system 700 includes one or more processors 710 coupled to a system memory 720 via an input/output (I/O) interface 730. Computer system 700 further includes a network interface 740 coupled to I/O interface 730, and one or more input/output devices, which can include one or more user interface (also referred to as "input interface") devices. In some cases, it is contemplated that embodiments may be implemented using a single instance of computer system 700, while in other embodiments multiple such systems, or multiple nodes making up computer system 700, may be configured to host different portions or instances of embodiments. For example, in one embodiment some elements may be implemented via one or more nodes of computer system 700 that are distinct from those nodes implementing other elements.

[0075] In various embodiments, computer system 700 may be a uniprocessor system including one processor 710, or a multiprocessor system including several processors 710 (e.g., two, four, eight, or another suitable number). Processors 710 may be any suitable processor capable of executing instructions. For example, in various embodiments processors 710 may be general- purpose or embedded processors implementing any of a variety of instruction set architectures (ISAs), such as the x86, PowerPC, SPARC, or MIPS ISAs, or any other suitable ISA. In multiprocessor systems, each of processors 710 may commonly, but not necessarily, implement the same ISA.

[0076] System memory 720 may be configured to store program instructions, data, etc. accessible by processor 710. For example, memory 720 of computer system 700 may include executable instructions 725 for performing various tasks. In various embodiments, system memory 720 may be implemented using any suitable memory technology, such as static random access memory (SRAM), synchronous dynamic RAM (SDRAM), nonvolatile/Flash-type memory, or any other type of memory. In the illustrated embodiment, program instructions included in memory 720 may be configured to implement some or all of a system for modeling charge transfer of a battery, incorporating any of the functionality described above. Additionally, existing control data of memory 720 may include any of the information or data structures described above. In some embodiments, program instructions and/or data may be received, sent or stored upon different types of computer-accessible media or on similar media separate from system memory 720 or computer system 700. While computer system 700 is described as implementing the functionality of functional blocks of previous Figures, any of the functionality described herein may be implemented via such a computer system.

[0077] In one embodiment, I/O interface 730 may be configured to coordinate I/O traffic between processor 710, system memory 720, and any peripheral devices in the device, including network interface 740 or other peripheral interfaces, such as input/output devices 750. In some embodiments, I/O interface 730 may perform any necessary protocol, timing or other data transformations to convert data signals from one component (e.g., system memory 720) into a format suitable for use by another component (e.g., processor 710). In some embodiments, I/O interface 730 may include support for devices attached through various types of peripheral buses, such as a variant of the Peripheral Component Interconnect (PCI) bus standard or the Universal Serial Bus (USB) standard, for example. In some embodiments, the function of I/O interface 730 may be split into two or more separate components, such as a north bridge and a south bridge, for example. Also, in some embodiments some or all of the functionality of I/O interface 730, such as an interface to system memory 720, may be incorporated directly into processor 710.

[0078] Network interface 740 may be configured to allow data to be exchanged between computer system 700 and other devices attached to a network 785 (e.g., carrier or agent devices) or between nodes of computer system 700. Network 785 may in various embodiments include one or more networks including but not limited to Local Area Networks (LANs) (e.g., an Ethernet or corporate network), Wide Area Networks (WANs) (e.g., the Internet), wireless data networks, some other electronic data network, or some combination thereof. In various embodiments, network interface 740 may support communication via wired or wireless general data networks, such as any suitable type of Ethernet network, for example; via telecommunications/telephony networks such as analog voice networks or digital fiber communications networks; via storage area networks such as Fiber Channel SANs, or via any other suitable type of network and/or protocol.

[0079] Input/output devices may, in some embodiments, include one or more display terminals, keyboards, keypads, touchpads, scanning devices, voice or optical recognition devices, or any other devices suitable for entering or accessing data by one or more computer systems 700. Multiple input/output devices may be present in computer system 700 or may be distributed on various nodes of computer system 700. In some embodiments, similar input/output devices may be separate from computer system 700 and may interact with one or more nodes of computer system 700 through a wired or wireless connection, such as over network interface 740.

[0080] Memory 720 may include program instructions, which may be processor-executable to implement any element or action described above. In one embodiment, the program instructions may implement the methods described above. In other embodiments, different elements and data may be included. Note that data may include any data or information described above.

[0081] Those skilled in the art will appreciate that computer system 700 is merely illustrative and is not intended to limit the scope of embodiments. In particular, the computer system and devices may include any combination of hardware or software that can perform the indicated functions, including computers, network devices, Internet appliances, PDAs, wireless phones, pagers, etc. Computer system 700 may also be connected to other devices that are not illustrated, or instead may operate as a stand-alone system. In addition, the functionality provided by the illustrated components may in some embodiments be combined in fewer components or distributed in additional components. Similarly, in some embodiments, the functionality of some of the illustrated components may not be provided and/or other additional functionality may be available.

[0082] Those skilled in the art will also appreciate that, while various items are illustrated as being stored in memory or on storage while being used, these items or portions of them may be transferred between memory and other storage devices for purposes of memory management and data integrity. Alternatively, in other embodiments some or all of the software components may execute in memory on another device and communicate with the illustrated computer system via inter-computer communication.

[0083] It should also be noted that the example software and/or firmware implementations described herein are optionally stored on a tangible storage medium, such as: a magnetic medium (e.g., a disk or tape); a magneto-optical or optical medium such as a disk; or a solid state medium such as a memory card or other package that houses one or more read-only (non-volatile) memories, random access memories, or other re-writable (volatile) memories; or a signal containing computer instructions. A digital file attachment to e-mail or other self-contained information archive or set of archives is considered a distribution medium equivalent to a tangible storage medium. Accordingly, the example software and/or firmware described herein can be stored on a tangible storage medium or distribution medium such as those described above or equivalents and successor media..

[0084] Although certain example devices, methods, apparatuses and articles of manufacture have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all devices, methods, apparatuses and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents. The scope of the present disclosure includes any feature or combination of features disclosed herein (either explicitly or implicitly), or any generalization thereof, whether or not it mitigates any or all of the problems addressed herein. Examples of features provided in the disclosure are intended to be illustrative rather than restrictive unless stated otherwise. Accordingly, new claims may be formulated during prosecution of this application (or an application claiming priority thereto) to any such combination of features. In particular, with reference to the appended claims, features from dependent claims may be combined with those of the independent claims and features from respective independent claims may be combined in any appropriate manner and not merely in the specific combinations enumerated in the appended claims.

[0085] The example devices, apparatuses, methods and/or modules described herein can be implemented by one or more software and/or firmware programs running on a computer processor. In addition, dedicated hardware implementations including, but not limited to, a circuit or circuits, including an interconnection of electrical components (e.g. batteries, resistors, inductors, capacitors, switches, transistors) consisting of electrical elements (e.g. voltage sources, current sources, resistances, inductances, capacitances), an ASIC, programmable logic arrays and other hardware devices can likewise be constructed to implement some or all of the example devices, apparatuses, methods and/or modules described herein, either in whole or in part. Furthermore, alternative software implementations including, but not limited to, distributed processing or component/object distributed processing, parallel processing, or virtual machine processing can also be constructed to implement the example devices, apparatuses methods and/or modules described herein.

[0086] Various modifications and changes may be made as would be obvious to a person skilled in the art having the benefit of this disclosure. The order of the blocks of the methods may be changed, and various elements may be added, reordered, combined, omitted, modified, etc. Many variations, modifications, additions, and improvements are possible. The various embodiments described herein are meant to be illustrative and not limiting. Other allocations of functionality are envisioned and may fall within the scope of claims that follow. Accordingly, plural instances may be provided for components described herein as a single instance. Finally, structures and functionality presented as discrete components in the example configurations may be implemented as a combined structure or component. These and other variations, modifications, additions, and improvements may fall within the scope of embodiments as defined in the claims that follow.

Claims

CLAIMS What is claimed is:

1. A system comprising:

a cell voltage measurement circuit, the cell voltage measurement circuit configured to measure a voltage of a first battery cell of a battery pack electrically coupled to the cell voltage measurement circuit;

a cell current measurement circuit configured to determine a cell current representing a current across a second battery cell of the battery pack, wherein the cell voltage measurement circuit and the cell current measurement circuit are configured to measure the respective cells of the battery pack at the same time; and

a battery management circuit configured to provide output representing remaining capability of the battery pack using the voltage of the first cell and the current across the second cell.

2. The system of claim 1, further comprising a clock configured to generate a clock signal having clock edges, wherein measuring the voltage of the first battery cell and the cell current of the second battery cell at the same time comprises measuring the cell voltage responsive to a clock edge and measuring the cell current responsive to the same clock edge.

3. The system of claim 1, wherein measuring the voltage of the first battery cell and the cell current of the second battery cell at the same time comprises measuring the voltage during a first time interval and the cell current during a second time interval, the second time interval at least partially overlapping with the first time interval.

4. The system of claim 1, wherein the cell voltage measurement circuit is further configured to measure a voltage of the second battery cell as it measures the voltage of the first battery cell, and wherein the battery management circuit is configured to provide the output also using the voltage of the second battery cell.

5. The system of claim 1, further comprising a multiplexer electrically coupled with a plurality of battery cells of the battery pack and the voltage measurement circuit, the multiplexer configured to selectably couple the cell voltage measurement circuit with a battery cell of the plurality of battery cells.

6. The system of claim 1, further comprising:

a non-transitory memory storing a model representing capability of the battery pack, wherein the battery management circuit is further configured to update the model using the voltage of the first battery cell and the current of the second battery cell.

7. The system of claim 6, further comprising an electron-counting circuit electrically coupled to the battery pack and configured to count electrons flowing in or out of the battery pack, wherein the battery management circuit is further configured to update the model using the electron-counting circuit.

8. The system of claim 6, wherein battery management circuit is further configured to determine an amount of electrical charge transfer by integrating the current of the second battery cell over a predetermined time interval, and wherein the cell current measurement circuit is configured to repeatedly determine cell current of the second battery at the predetermined time interval.

9. The system of claim 1, wherein the cell current measurement circuit is configured to match at least one filter characteristic of the cell voltage measurement circuit.

10. A method comprising:

measuring a voltage of a first battery cell of a battery pack;

determining a cell current representing a current across a second battery cell of the battery pack, wherein the voltage of the first battery cell is measured and the cell current of the second battery cell is determined at the same time; and

providing output representing remaining capability of the battery pack using the voltage of the first cell and the current across the second cell.

11. The method of claim 10, further comprising generating a clock signal having clock edges, wherein measuring the voltage of the first battery cell and determining the cell current of the second battery cell at the same time comprises measuring the cell voltage responsive to a clock edge and determining the cell current responsive to the same clock edge.

12. The method of claim 10, wherein measuring the voltage of the first battery cell and determining the cell current of the second battery cell at the same time comprises measuring the voltage during a first time interval and determining the cell current during a second time interval, the second time interval at least partially overlapping with the first time interval.

13. The method of claim 10, further comprising measuring a voltage of the second battery cell as the voltage of the first battery cell is measured, and wherein providing output representing the remaining capability of the battery pack further comprises using the voltage of the second battery cell.

14. The method of claim 10, further comprising:

storing a model representing capability of the battery pack, and

updating the model using the voltage of the first battery cell and the current of the second battery cell.

15. The method of claim 10, wherein the determining of the cell current representing the current across the second battery cell of the battery pack further comprises matching at least one filter characteristic used when measuring the voltage of the first battery cell of the battery pack.

16. A non-transitory computer-readable storage medium storing computer-executable program instructions to perform:

measuring a voltage of a first battery cell of a battery pack;

17. The non-transitory computer-readable storage medium as recited in claim 16, wherein measuring the voltage of the first battery cell and determining the cell current of the second battery cell at the same time comprises measuring the voltage during a first time interval and determining the cell current during a second time interval, the second time interval at least partially overlapping with the first time interval.

18. The non-transitory computer-readable storage medium as recited in claim 16, further comprising measuring a voltage of the second battery cell as the voltage of the first battery cell is measured, and wherein providing output representing the remaining capability of the battery pack further comprises using the voltage of the second battery cell.

19. The non-transitory computer-readable storage medium as recited in claim 16, further comprising:

storing a model representing capability of the battery pack, and

20. The non-transitory computer-readable storage medium as recited in claim 16, wherein the determining of the cell current representing the current across the second battery cell of the battery pack further comprises matching at least one filter characteristic used when measuring the voltage of the first battery cell of the battery pack.