Aspects of the present disclosure analyzing one or more signals that include both uncorrelated random signals as well as correlated information pertaining to electrochemical and/or electrodynamic processes occurring within a battery, characterizing the battery for charging, discharging, storage and other uses and/or controlling charging, discharging and other aspects of battery management based on the same.
Battery powered devices have proliferated and become ubiquitous. Device manufactures are constantly pressing for performance improvement in batteries, particularly as batteries are introduced into devices with relatively higher current demands and power needs. At the same time, consumers demand longer battery life, longer times between charges, and shorter charge times. As such, there is an ongoing and continuous need for improvements in how batteries are managed, charged and discharged to enhance performance. It is with these observations in mind, among many others, that the various aspects of the present disclosure were conceived.
Aspects of the present disclosure involve a method comprising accessing a noisy signal from a battery where the noisy signal includes uncorrelated noise and correlated signal data and filtering the noisy signal to isolate the correlated signal data. The method further involves processing the correlated signal data to identify at least one of an electrochemical or electrodynamic process within the battery. In various possible implementations, the noisy signal is a voltage measurement or a current measurement at the battery. The signal may also be accessed from memory. The noisy signal may also be a generated measurement, such as an impedance measurement (determination) from at least one of a current measurement and a voltage measurement.
The signal may be obtained during an equilibrium state of the battery, which may be during charge or discharge, or from a probe signal. The equilibrium state of the battery may be considered and occur during a zero-net change to the battery. The signal may also be obtained in a transient state of the battery, which may be associated with a charge signal or a discharge signal. The method may further include filtering the noisy data, such as by way of a domain transform or other filtering technique, to identify the correlated signal data. The domain transform may be one of a partial or fractional domain transform.
The correlated signal data may be associated with plating, and/or dendrite formation and growth. More generally, the correlated signal data may be associated with electrodynamic behavior in the battery. As such, the system and methods discussed herein may act on the identification of electrodynamic behavior of the battery. Conversely, the uncorrelated signal data may be thermal, which can be seen as noise, and hence removing thermal information may help isolate the correlated signal data.
In various possible aspects processing the correlated signal data may involve identifying a bifurcation where a bifurcation is indicative of the onset of an additional electrochemical or electrodynamic process, such as intercalation following by plating being the additional process.
The method may further involve altering a charge parameter (or discharge parameter) based on the identification of the electrochemical or electrodynamic process within the battery.
Another aspect of the present disclosure involves a method comprising, from a signal of an electrochemical device including uncorrelated data and correlated data including pertaining to electrochemical or electrodynamic process of the electrochemical device, filtering the signal to identify the correlated data including information pertaining to the electrochemical or electrodynamic process; and altering a charge parameter based, at least in part, on identification of a bifurcation in the filtered signal. The electrochemical device may be a batter and the signal may be obtained, e.g., measured, during charge or discharge. The charge parameter that is altered may be charge rate, charge voltage and/or duty cycle depending on the type of charge signal. The charge parameter may also comprise a harmonic component of the charge signal.
These and other aspects of the disclosure are described in further detail below.
Aspects of the present disclosure involve a new understanding that electrodynamic and electrochemical processes in electrochemical systems, particularly rechargeable batteries, may be identified from what would normally be considered discardable data. In a general sense, “noise” in electrical systems is considered to consist of uncorrelated completely random signal data and is typically ignored or efforts are made to suppress or remove it. In the present application, however, signals that would normally be considered noisy are understood to contain information that may be associated with events occurring in the battery. The detection of such events and the manipulation of such signals, alone or in combination, may be further used to alter various actions on the battery such as charging or discharging. While aspects of this disclosure are discussed primarily in the context of battery charging and discharging, aspects of the disclosure are also applicable to other environments including electroplating systems.
The term “battery” in the art and herein can be used in various ways and may refer to an individual cell having an anode and cathode separated by an electrolyte, solid or liquid, as well as a collection of such cells connected in various arrangements. A battery or battery cell is a form of electrochemical device. Batteries generally comprise repeating units of sources of a countercharge and electrode layers separated by an ionically conductive barrier, often a liquid or polymer membrane saturated with an electrolyte. These layers are made to be thin so multiple units can occupy the volume of a battery, increasing the available power of the battery with each stacked unit. Although many examples are discussed herein as applicable to a battery, it should be appreciated that the systems and methods described may apply to many different type of batteries ranging from an individual cell to batteries involving different possible interconnections of cells such as cells coupled in parallel, series, and parallel and series. For example, the systems and methods discussed herein may apply to a battery pack comprising numerous cells arranged to provide a defined pack voltage, output current, and/or capacity. Moreover, the implementations discussed herein may apply to different types of electrochemical devices such as various different types of lithium batteries including but not limited to lithium-metal and lithium-ion batteries, lead-acid batteries, various types of nickel batteries, and solid-state batteries, to name a few. The various implementations discussed herein may also apply to different structural battery arrangements such as button or “coin” type batteries, cylindrical cells, pouch cells, and prismatic cells.
To begin, an unfiltered signal, which may appear noisy, or carefully filtered signal is captured from the battery. For example, the system may include a filter or filters targeted at filtering out readily identified hardware or other forms of ancillary noise. Stated differently, the filter or filters may be set or defined to remove signal data that is known to be related to hardware and environmental contributions (e.g., thermal effects) and not be related to battery dynamics, such as internal battery electrodynamics. The signal may be captured during steady state (equilibrium). The signal may also be captured in the presence of a probe signal. The probe signal may be a dedicated probing signal or may be a charge signal. The signal may also be captured during discharge. In one specific example, the probe signal is a charge signal and includes transient portions and steady state portions.
More particularly and as introduced above, within the noisy appearing data includes correlated signals masquerading as uncorrelated noise. This correlated data is captured with the uncorrelated information. The correlated (deterministic) signals are associated with electrochemical and electrodynamic processes occurring within the battery. As such, and in accordance with aspects of the present disclosure, a myriad of useful information may be obtained by isolating the correlated information, associating that information with some event occurring in the battery, and/or then acting on that information and event correlation to alter charge, discharge, characterization parameters or other actions on or in relation to the battery. Conventionally, there has not believed to have been a recognition that there is an association between electrochemical and electrodynamic information and correlated signal character hidden within complex noise. Similarly, there has not been any attempt to use such information to manage electrical energy used to charge or discharge a battery, electroplate or otherwise.
In one example, during equilibrium (steady state), when there is no charge or discharge of the battery, there are some electrochemical processes occurring involving ion diffusion, intercalation and deintercalation, for example. Typically, there are no net changes associated with such equilibrium activity. These steady state processes are nonetheless reflected in and can be identified from correlated signals that may be isolated from and otherwise detected in the measured signal.
In another example, correlated signals within the broader data signal may be reflective of lithium plating and may be used to identify such events. Lithium plating can lead to dendrite growth among other concerns. During charging, lithium ions from the cathode insert into the anode in a process referred to as intercalation. At the same time, lithium may plate the anode, which is undesirable and can lead to various problems including capacity degradation and increased internal cell resistance. Dendrite growth can be associated with capacity degradation and also further lead to short circuit conditions, which may lead to battery failure. There are some known causes for plating including charging at a rate that exceeds the rate at which some ions can intercalate (a rate considered too high) and charging at too low a temperature where ions cannot efficiently intercalate. Besides altering a charge signal, upon determination of the onset of plating, the system may also wait until temperature increases to an acceptable threshold to resume charging.
In accordance with aspects of the present disclosure, it has been further discovered that plating, including dendrite formation and growth, may also be caused or exacerbated by uncontrolled charge signal noise, particularly relatively high frequency charge signal noise. This noise may originate from processes inside the cell, from external sources such as nearby electrical components or radiating signals, or from frequent alternation between net charge and discharge states, and other sources. Uncontrolled charge signal noise is seen to be associated with electrodynamic effects and conductive pathway concentration in the anode, cathode, and/or associated current collectors. The electrodynamic noise induced conductive pathways may then cause localized current concentrations leading to plating and dendrite formation. Aspects of the present disclosure thus involve identifying such conditions, and countering or otherwise mitigating uncontrolled noise.
To address some or all of these issues, as well as others, one particular aspect of the present disclosure involves identifying plating within the unaltered or carefully altered (e.g., filtered, as discussed above) signal and further may involve altering some condition (e.g., some aspect of the charge signal) to reduce or eliminate plating. The ability to detect plating in the correlated data, which may be a part of an otherwise noisy signal with uncorrelated data, may be based, at least in part, by the realization that plating and dendrite formation and growth are 3-dimensional, and sometimes fractal in nature. Filtering signal data to isolate or otherwise identify the correlated content, and then further processing, which may involve various assessments of statistical and deterministic nature, may be used to identify plating and act on it.
In terms of state of charge and as introduced above regarding plating, charging involves ion diffusion from the cathode to the anode. As the state of charge rises, the diffusion patterns change as available ions in the cathode and the intercalation activity at the anode declines. This activity is reflected in correlated signals within signal the data from a battery, related to both electrochemical and electrodynamic processes, and may thus be identified according to the techniques discussed herein.
While many processes are in play within a battery while it is being charged, in one example, one favorable and what might be considered normal and harmless process within the battery involves ion diffusion from the cathode to the anode. As mentioned above, under some unfavorable charge conditions, plating and dendrite growth may occur. It is also the case that as a battery approaches a full state of charge, the diffusive processes from the cathode to the anode reduce as the available lithium inventory lessens. The energy normally that would be going to battery healthy charging may then instead go into plating. In conventional processes because the electrokinetics of diffusion and plating are dependent and occur in series, the two processes are exceedingly difficult to distinguish and the onset of plating exceedingly difficult to distinguish from healthy charge transfer reactions. In one aspect of the present disclosure, however, correlated data during charge is processed to identify bifurcations. The onset of a bifurcation is representative of the onset of a distinct process within the data. In the case of correlated data extracted from a data signal during charge, a method may involve generating a bifurcation data set (commonly displayed as a bifurcation diagram) and identifying the occurrence of a bifurcation. Leading to the bifurcation may be indicative of change from healthy diffusion during charge and the transition to an additional process, such as plating, at the bifurcation indicative that charge energy is being used for both charging and plating. As such, upon the identification of a bifurcation, the system may alter the charge signal, such as by reducing the charge current, reducing the charge voltage, reducing both, altering a duty cycle, altering pulse characteristics, or making other charge signal changes.
Healthy cathodic phase changes may also occur during charging. Such a change may also be identified through a bifurcation. Assessing state of charge or acting on information during charging may be based on various parameters such as identifying the onset of plating and identifying cathodic phase changes, alone or in a myriad of combinations. For example, in the presence of a bifurcation related to the onset of plating, a charge signal may be reduced (e.g., reducing charge current), as noted above, to thereby reduce charge energy to have the effect of stopping plating. The system may then assess or assume that plating has been halted, and continue analyzing the correlated data until the onset of another bifurcation, and then repeat the process (altering charge parameters). It should be recognized that the process may be done in conjunction with an SOC assessment, or voltage level assessment, or other additional sets of information to identify when charging is complete—e.g., 100%.
The non-uniform plating and dendrite formation and growth, among other things, may be understood to be fractal in nature. Moreover, some processes and other battery processes that are fractal in nature are considered undesirable, while others may be considered normal and not damaging or otherwise undesirable. As such, correlated data within the signal may generally be characterized as fractal, which leads to opportunities to process the data as the same, and then associate the data with some undesirable or favorable processes within the cell. Moreover, when correlated signals are isolated from actual noise in the signal, the correlated signals may be processed using various statistical analytical techniques, some of which are directly or tangentially related to impedance and electrochemical physics, and others which are distinct from impedance-based parameters and reflective of broader electrodynamics. Numerous examples are possible including the generation of bifurcation data as discussed above and the generation of a Lyapunov exponent. Such may be correlated in relation to state of charge, state of health, instantaneous degradation, temperature distribution, voltage, current, impedance, and other useful metrics. Processing, alone or in various processing combinations, of the correlated signals yields information indicative of various desirable or otherwise normal electrochemical and electrodynamic processes as well as undesirable processes.
The information itself is valuable in characterizing a battery and is valuable in charge or discharge control of a battery, as well as other values, such as health generation of the battery (a process which is neither charging or discharging in a conventional sense). The information may also be useful in charge or discharge control. For example, detection of early onset plating, and modification of the charge signal to avoid the same contributes to longer battery cycle life, battery capacity, charge rate, capacity utilization, and battery safety among other things. Detection of state of charge has a myriad of similar advantages including greater battery capacity utilization, effective charge rate control, discharge control, greater cycle life, and battery safety overall.
Referring to
The computing system 400 may process various signals (e.g.,
The computer system 400 may be a computing system that is capable of executing a computer program product to execute a computer process. Data and program files may be input to the computer system 400, which reads the files and executes the programs therein. Some of the elements of the computer system 400 are shown in
The processor 402 may include, for example, a central processing unit (CPU), a microprocessor, a microcontroller, a digital signal processor (DSP), and/or one or more internal levels of cache. There may be one or more processors 402, such that the processor 402 comprises a single central-processing unit, or a plurality of processing units capable of executing instructions and performing operations in parallel with each other, commonly referred to as a parallel processing environment.
The presently described technology in various possible combinations may be implemented, at least in part, in software stored on the data stored device(s) 404, stored on the memory device(s) 406, and/or communicated via one or more of the ports 408-412, thereby transforming the computer system 400 in
The one or more data storage devices 404 may include any non-volatile data storage device capable of storing data generated or employed within the computing system 400, such as computer executable instructions for performing a computer process, which may include instructions of both application programs and an operating system (OS) that manages the various components of the computing system 400. The data storage devices 404 may include, without limitation, magnetic disk drives, optical disk drives, solid state drives (SSDs), flash drives, and the like. The data storage devices 404 may include removable data storage media, non-removable data storage media, and/or external storage devices made available via a wired or wireless network architecture with such computer program products, including one or more database management products, web server products, application server products, and/or other additional software components. Examples of removable data storage media include Compact Disc Read-Only Memory (CD-ROM), Digital Versatile Disc Read-Only Memory (DVD-ROM), magneto-optical disks, flash drives, and the like. Examples of non-removable data storage media include internal magnetic hard disks, SSDs, and the like. The one or more memory devices 406 may include volatile memory (e.g., dynamic random-access memory (DRAM), static random-access memory (SRAM), etc.) and/or non-volatile memory (e.g., read-only memory (ROM), flash memory, etc.).
Computer program products containing mechanisms to effectuate the systems and methods in accordance with the presently described technology may reside in the data storage devices 404 and/or the memory devices 406, which may be referred to as machine-readable media. It will be appreciated that machine-readable media may include any tangible non-transitory medium that is capable of storing or encoding instructions to perform any one or more of the operations of the present disclosure for execution by a machine or that is capable of storing or encoding data structures and/or modules utilized by or associated with such instructions. Machine-readable media may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more executable instructions or data structures.
In some implementations, the computer system 400 includes one or more ports, such as an input/output (I/O) port 408, a communication port 410, and a sub-systems port 412, for communicating with other computing, network, or vehicle devices. It will be appreciated that the ports 408-412 may be combined or separate and that more or fewer ports may be included in the computer system 400. The I/O port 408 may be connected to an I/O device, or other device, by which information is input to or output from the computing system 400. Such I/O devices may include, without limitation, one or more input devices, output devices, and/or environment transducer devices.
In one implementation, the input devices convert a human-generated signal, such as, human voice, physical movement, physical touch or pressure, and/or the like, into electrical signals as input data into the computing system 400 via the I/O port 408. In some examples, such inputs may be distinct from the various system and method discussed with regard to the preceding figures. Similarly, the output devices may convert electrical signals received from computing system 400 via the I/O port 408 into signals that may be sensed or used by the various methods and system discussed herein. The input device may be an alphanumeric input device, including alphanumeric and other keys for communicating information and/or command selections to the processor 402 via the I/O port 408.
The environment transducer devices convert one form of energy or signal into another for input into or output from the computing system 400 via the I/O port 408. For example, an electrical signal generated within the computing system 400 may be converted to another type of signal, and/or vice-versa. In one implementation, the environment transducer devices sense characteristics or aspects of an environment local to or remote from the computing device 400, such as battery voltage, open circuit battery voltage, charge current, battery temperature, light, sound, temperature, pressure, magnetic field, electric field, chemical properties, and/or the like.
In one implementation, a communication port 410 may be connected to a network by way of which the computer system 400 may receive network data useful in executing the methods and systems set out herein as well as transmitting information and network configuration changes determined thereby. For example, charging protocols may be updated, battery measurement or calculation data shared with external system, and the like. The communication port 410 connects the computer system 400 to one or more communication interface devices configured to transmit and/or receive information between the computing system 400 and other devices by way of one or more wired or wireless communication networks or connections. Examples of such networks or connections include, without limitation, Universal Serial Bus (USB), Ethernet, VVi-Fi, Bluetooth®, Near Field Communication (NFC), Long-Term Evolution (LTE), and so on. One or more such communication interface devices may be utilized via the communication port 410 to communicate with one or more other machines, either directly over a point-to-point communication path, over a wide area network (WAN) (e.g., the Internet), over a local area network (LAN), over a cellular (e.g., third generation (3G), fourth generation (4G), fifth generation (5G)) network, or over another communication means.
The computer system 400 may include a sub-systems port 412 for communicating with one or more systems related to a device being charged according to the methods and system described herein to control an operation of the same and/or exchange information between the computer system 400 and one or more sub-systems of the device. Examples of such sub-systems of a vehicle, include, without limitation, motor controllers and systems, battery control systems, and others.
The system set forth in
Embodiments of the present disclosure include various steps, which are described in this specification. The steps may be performed by hardware components or may be embodied in machine-executable instructions, which may be used to cause a general-purpose or special-purpose processor programmed with the instructions to perform the steps. Alternatively, the steps may be performed by a combination of hardware, software and/or firmware.
Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments, also referred to as implementations or examples, described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations together with all equivalents thereof.
While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without parting from the spirit and scope of the disclosure. Thus, the following description and drawings are illustrative and are not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of the disclosure. However, in certain instances, well-known or conventional details are not described in order to avoid obscuring the description. References to one or an embodiment in the present disclosure can be references to the same embodiment or any embodiment; and, such references mean at least one of the embodiments.
Reference to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. The appearances of the phrase “in one embodiment”, or similarly “in one example” or “in one instance”, in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others.
The terms used in this specification generally have their ordinary meanings in the art, within the context of the disclosure, and in the specific context where each term is used. Alternative language and synonyms may be used for any one or more of the terms discussed herein, and no special significance should be placed upon whether or not a term is elaborated or discussed herein. In some cases, synonyms for certain terms are provided. A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only and is not intended to further limit the scope and meaning of the disclosure or of any example term. Likewise, the disclosure is not limited to various embodiments given in this specification.
Without intent to limit the scope of the disclosure, examples of instruments, apparatus, methods and their related results according to the embodiments of the present disclosure are given below. Note that titles or subtitles may be used in the examples for convenience of a reader, which in no way should limit the scope of the disclosure. Unless otherwise defined, technical and scientific terms used herein have the meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In the case of conflict, the present document, including definitions will control.
Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or can be learned by practice of the herein disclosed principles. The features and advantages of the disclosure can be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the disclosure will become more fully apparent from the following description and appended claims or can be learned by the practice of the principles set forth herein.
This application is related to and claims priority under 35 U.S.C. § 119(e) from U.S. Patent Application No. 63/324,505 filed Mar. 28, 2022, titled “Noise,” the entire contents of which is incorporated herein by reference for all purposes.
Number | Date | Country | |
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63324505 | Mar 2022 | US |