Device and method for analyzing impedance characteristics of a battery and energy storage system

Abstract

The present application provides a device and method for analyzing impedance characteristics of a battery and an energy storage system. The device for analyzing impedance characteristics of a battery includes a switch configured to allow or block current flow along a path for supplying a charging current to the battery or extracting a discharging current from the battery, and a processor configured to derive impedance characteristics of the battery using a method of generating an excitation current for deriving the impedance characteristics of the battery from the charging current by controlling on / off operations of the switch when the charging current for charging the battery is supplied through the path.

Description

[0001] This application claims priority and benefit to Korean Patent Application No. 10-2024-0184492, filed on December 12, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure relates to apparatus and methods for analyzing the impedance characteristics of batteries and energy storage systems (ESS). Background Technology

[0003] An energy storage system (ESS) is a system that can store surplus electricity or electricity generated using new renewable energy sources. During periods of low electricity demand, ESS can be used to store idle electricity; and during periods of high electricity demand, the electricity stored in the ESS can be supplied to the grid system and consumers, enabling smooth control of electricity supply and demand.

[0004] An ESS (Energy Storage System) includes a battery used for storing or extracting electrical energy. An ESS may further include: a Battery Management System (BMS) that monitors the battery's state and controls the battery or performs protective operations based on the monitoring results; a Power Conversion System (PCS) that performs AC-DC conversion and power distribution functions between the grid system and the battery; and an Energy Management System (EMS) that monitors the ESS's operating status, collects and manages status data, and provides overall control of the ESS. A battery comprises multiple battery racks electrically connected to each other, each battery rack comprising multiple battery modules electrically connected to each other, and each battery module comprising multiple battery cells electrically connected to each other.

[0005] The information disclosed above in the Background section is intended to enhance the understanding of the background of this disclosure, and therefore may contain information that does not constitute related (or prior art). Summary of the Invention

[0006] An aspect of the present invention relates to an apparatus and method for analyzing the impedance characteristics of a battery, which can improve the accuracy of impedance characteristic analysis of batteries (e.g., individual cells, battery modules, or battery racks) used in battery devices such as energy storage systems (ESS), and an aspect of the present invention also relates to an ESS.

[0007] However, the objectives of this invention are not limited to those described above, and those skilled in the art will clearly understand other objectives not described based on the following description.

[0008] According to some embodiments of the present invention, an apparatus for analyzing the impedance characteristics of a battery is provided, the apparatus comprising: a switch configured to allow or block current flow along a path for supplying charging current to the battery or extracting discharging current from the battery; and a processor configured to derive the impedance characteristics of the battery using a method of generating an excitation current from the charging current for deriving the impedance characteristics of the battery by controlling the on / off operation of the switch when the charging current for charging the battery is supplied via the path.

[0009] In some embodiments, the device further includes a current sensing element configured to detect current flowing along a path, wherein the processor is configured to derive the impedance characteristics of the battery based on voltage characteristic parameters of the battery when an excitation current generated from the charging current is applied to the battery and current characteristic parameters of the excitation current obtained by the current sensing element.

[0010] In some embodiments, the processor is configured to control the on / off operation of the switch according to a pulse width modulation (PWM) method to generate an excitation current in the form of PWM pulses.

[0011] In some embodiments, the processor is configured to control the on / off operation of the switch to keep the excitation current within a certain frequency range.

[0012] In some embodiments, the voltage characteristic parameter represents the frequency-dependent voltage value of the battery, and the current characteristic parameter represents the frequency-dependent value of the excitation current; and the processor is configured to derive the frequency-dependent impedance characteristics of the battery based on the voltage characteristic parameter and the current characteristic parameter.

[0013] In some embodiments, the processor is configured to derive the impedance characteristics of a battery in the form of a Nyquist plot.

[0014] In some embodiments, the processor is further configured to analyze battery aging by comparing the battery's impedance value at the target analysis frequency with a reference impedance value at the target analysis frequency.

[0015] In some embodiments, the processor is configured to control the charging current to the battery according to constant current-constant voltage (CC-CV); and the processor is configured to derive the impedance characteristics of the battery in CV mode.

[0016] In some embodiments, the processor is configured to control the on / off operation of a switch to generate an excitation current at a time point after a set time has elapsed since the CV mode was started.

[0017] In some embodiments, the duration of the set time is greater than or equal to half of the total time during which the CV mode is executed.

[0018] In some embodiments, the battery includes a plurality of battery cells; and the processor that generates the excitation current is defined as a main processor, and the device further includes: acquiring voltage characteristic parameters from the processor for each of the plurality of battery cells, and transmitting the voltage characteristic parameters to the main processor.

[0019] In some embodiments, the main processor is configured to derive the impedance characteristics of the battery for each of the plurality of battery cells using voltage characteristic parameters and current characteristic parameters of the excitation current obtained for each of the plurality of battery cells.

[0020] In some embodiments, the battery is formed by connecting multiple battery modules, including multiple battery cells, in series, in parallel, or in a series-parallel combination; the slave processor includes multiple slave processors, each corresponding to one of the multiple battery modules; and the master processor and the multiple slave processors are connected in a daisy chain.

[0021] According to some embodiments of the present invention, an energy storage system (ESS) is provided, comprising: a battery; a switch configured to allow or block current flow along a path for supplying charging current to the battery or extracting discharging current from the battery; and a battery management system (BMS) configured to derive the impedance characteristics of the battery using a method of generating an excitation current from the charging current for deriving the impedance characteristics of the battery by controlling the on / off operation of the switch when the charging current for charging the battery is supplied via the path.

[0022] According to some embodiments of the present invention, a method for analyzing the impedance characteristics of a battery is provided, the method comprising: generating an excitation current from the charging current for deriving the impedance characteristics of the battery by a processor controlling the on / off operation of a switch when a charging current for charging the battery is supplied via a path, wherein the path is used to supply charging current to the battery or extract discharging current from the battery, and the switch allows or prevents current from flowing along the path; and deriving the impedance characteristics of the battery by the processor when the excitation current generated from the charging current is applied to the battery.

[0023] In some embodiments, in the derivation of impedance characteristics, the processor is configured to: acquire the voltage characteristic parameters of the battery when an excitation current generated from the charging current is applied to the battery; acquire the current characteristic parameters of the excitation current by means of a current sensing element provided on the path; and derive the impedance characteristics of the battery based on the voltage characteristic parameters and the current characteristic parameters.

[0024] In some embodiments, in the generation of excitation current, the processor is configured to control the on / off operation of the switch according to a pulse width modulation (PWM) method to generate an excitation current in the form of PWM pulses within a certain frequency range.

[0025] In some embodiments, the voltage characteristic parameter represents the voltage value of the battery at a given frequency, and the current characteristic parameter represents the value of the excitation current at a given frequency; and in the derivation of the impedance characteristics, the processor is configured to derive the impedance characteristics of the battery at a given frequency based on the voltage characteristic parameter and the current characteristic parameter.

[0026] In some embodiments, the method further includes: the processor analyzing battery aging by comparing the battery's impedance value at the target analysis frequency with a reference impedance value at the target analysis frequency.

[0027] In some embodiments, the charging current charges the battery according to constant current-constant voltage (CC-CV); and the generation of the excitation current and the derivation of the impedance characteristics are triggered at a time point after a set time has elapsed since the CV mode is started.

[0028] However, the effects achievable by the present invention are not limited to those described above, and those skilled in the art can clearly understand other effects not described based on the specific embodiments. Attached Figure Description

[0029] The accompanying drawings illustrate embodiments of the present disclosure and, together with the detailed description of specific implementations, further describe aspects and features of the present disclosure. Therefore, this disclosure should not be construed as limited to the drawings, in which:

[0030] Figure 1 and Figure 2 This is an example diagram illustrating a circuit used to perform general electrochemical impedance spectroscopy (EIS) according to some embodiments of the present invention;

[0031] Figure 3 This is a block diagram illustrating an energy storage system (ESS) according to some embodiments of the present invention;

[0032] Figure 4 This is a circuit diagram illustrating an apparatus for analyzing the impedance characteristics of a battery according to some embodiments of the present invention.

[0033] Figure 5 This is an example diagram illustrating the Nyquist plot of the impedance characteristics of a battery according to some embodiments of the present invention; and

[0034] Figure 6 This is a flowchart illustrating a method for analyzing the impedance characteristics of a battery according to some embodiments of the present invention. Detailed Implementation

[0035] In the following description, some embodiments of this disclosure will be described in detail with reference to the accompanying drawings. The terms or words used in this specification and claims should not be construed as limited to their ordinary or dictionary meanings, but should be understood based on the principle that the inventor can be his / her own lexicographer to appropriately define the concepts of the terms so as to best interpret his / her invention, and are thus understood to be consistent with the technical spirit of this disclosure.

[0036] The embodiments described in this specification and the configurations shown in the accompanying drawings are merely some of the embodiments of this disclosure and do not represent all the technical ideas, aspects, and features of this disclosure. Accordingly, it should be understood that various equivalents and modifications may exist at the time of filing this application to replace or modify the embodiments described herein.

[0037] It will be understood that when an element or layer is referred to as being "on" another element or layer, "connected to," or "coupled to" another element or layer, it can be directly on, directly connected to, or directly coupled to that other element or layer, or one or more intermediary elements or layers may be present. When an element or layer is referred to as being "directly on" another element or layer, "directly connected to," or "directly coupled to" another element or layer, no intermediary element or layer is present. For example, when a first element is described as being "coupled" or "connected" to a second element, the first element can be directly coupled to or directly connected to the second element, or the first element can be indirectly coupled to or indirectly connected to the second element via one or more intermediary elements.

[0038] In the figures, the dimensions of various elements, layers, etc., may be exaggerated for clarity. The same reference numerals refer to the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the listed related items. Furthermore, when describing embodiments of this disclosure, the use of "may" refers to "one or more embodiments of this disclosure." When following a list of elements, expressions such as "at least one of..." and "any one of..." modify the entire list of elements, not individual elements in the list. When phrases such as "at least one of A, B, and C," "at least one of A, B, or C," "at least one selected from the group consisting of A, B, and C," or "at least one selected from A, B, and C" are used to refer to a list of elements A, B, and C, the phrase may refer to any and all suitable combinations of A, B, and C, or a subset of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the terms “use,” “in use,” and “being used” may be considered synonymous with the terms “exploitation,” “being exploited,” and “being exploited,” respectively. As used herein, the terms “substantially,” “approximately,” and similar terms are used as terms of approximation, not as terms of degree, and are intended to explain the inherent variations in measurements or calculations that will be recognized by one of ordinary skill in the art.

[0039] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Therefore, the first element, component, region, layer, or portion discussed below may be referred to as the second element, component, region, layer, or portion without departing from the teachings of the exemplary embodiments.

[0040] For ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” and “above” may be used herein to describe the relationship between one element or feature illustrated in the figures and another element(s). It will be understood that, in addition to the orientation depicted in the figures, the spatial relative terms are intended to cover different orientations of the device in use or operation. For example, if the device in the figures is flipped, the element described as “below” or “under” other elements or features will be oriented “above” or “above” other elements or features. Thus, the term “below” can encompass both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptive terms used herein should be interpreted accordingly.

[0041] The terminology used herein is for the purpose of describing embodiments of this disclosure and is not intended to limit the disclosure. As used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly indicates otherwise. It will be further understood that, when used in this specification, the terms “comprising,” “including,” and / or variations thereof indicate the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0042] Furthermore, any numerical range disclosed and / or described herein is intended to include all subranges with the same numerical precision contained within the described range. For example, the range “1.0 to 10.0” is intended to include all subranges between the described minimum value 1.0 and the described maximum value 10.0 (and including both the described minimum value 1.0 and the described maximum value 10.0), i.e., all subranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Accordingly, the applicant reserves the right to modify this specification (including the claims) to expressly describe any subranges contained within the range expressly described herein.

[0043] Referring to two compared elements, features, etc., as “identical” can mean that they are “substantially identical.” Therefore, the phrase “substantially identical” can include cases where there is a deviation considered low in the art (e.g., less than 5%). Furthermore, when a parameter is said to be uniform in a given region, this can mean that it is uniform in terms of average value.

[0044] Throughout this specification, each element may be singular or plural unless otherwise stated.

[0045] When any element is referred to as being disposed (positioned or located on) "above (or below)" or "on (or below)" a component, this may mean that the element is positioned in contact with the upper (or lower) surface of the component, and may also mean that another component may be inserted between the component and any element disposed (positioned or located on) the component.

[0046] Furthermore, it will be understood that when an element is referred to as “linked,” “coupled,” or “connected” to another element, these elements may be directly “coupled,” “linked,” or “connected” to each other, or there may be an intermediary element through which the element can be “coupled,” “linked,” or “connected” to the other element. Additionally, when a part is referred to as “electrically coupled” to another part, the part may be directly connected to the other part, or there may be an intermediary part that indirectly connects the part and the other part to each other.

[0047] Throughout this specification, when “A and / or B” is mentioned, it means A, B, or A and B, unless otherwise stated. That is, “and / or” includes any or all of the listed items. When “C to D” is mentioned, it means C and below, unless otherwise stated.

[0048] Figure 1 and Figure 2 This is an example diagram illustrating a circuit used to perform general electrochemical impedance spectroscopy (EIS).

[0049] EIS (Electronic Information System) is widely used for analyzing the impedance characteristics of batteries and is performed by applying an AC current or AC voltage to the battery and analyzing the battery's impedance response to the AC current or AC voltage. EIS analysis for batteries can also be performed as EIS analysis at the battery pack level (e.g., see [link to EIS analysis]). Figure 1 ) or as a battery module-level EIS analysis (e.g., see Figure 2 ) to execute.

[0050] For EIS analysis at the battery pack level and EIS analysis at the battery module level, such as Figure 1 and Figure 2 As shown, an excitation current extraction circuit is used, connected in parallel with the battery. The excitation current extraction circuit consists of a drive switch SW and a current-limiting resistor R connected in series. When the drive switch SW is closed, a closed circuit is formed in which the battery pack is connected to the excitation current extraction circuit, and an excitation current is extracted from the battery pack. As the excitation current flows in the closed circuit, the current I and voltage V of the battery pack are measured, and the impedance of the battery pack is derived based on the measured current and voltage.

[0051] exist Figure 1 and Figure 2In the EIS analysis example presented, the excitation current used for the EIS analysis is extracted from the battery, which is the target of impedance measurement. This limits the accuracy of the corresponding battery impedance analysis, and there is also the issue of energy loss within the battery itself. Furthermore, heat generation in the drive switch SW and current-limiting resistor R, which constitute the excitation current extraction circuit, as well as power loss in the current-limiting resistor R, also contribute to reducing the accuracy of the battery impedance measurement. To improve the accuracy of the battery impedance analysis, the value of the excitation current should be increased, but this also leads to a proportional decrease in the battery's available energy with the increase of the excitation current value.

[0052] Therefore, according to some embodiments, EIS analysis is performed by using a method of generating an excitation current from the charging current of the battery, instead of using the excitation current extracted from the battery as the target of impedance analysis to analyze the battery impedance, so as to accurately analyze the impedance characteristics of the battery, without the problems of decreased battery available energy and decreased impedance analysis accuracy due to heat generated in the peripheral circuit.

[0053] In addition to being applicable to ESS (Emergency Safe Battery), the apparatus for analyzing the impedance characteristics of a battery (hereinafter referred to as "the apparatus") according to some embodiments can also be applied to battery devices such as general-purpose battery packs with a battery management system (BMS). Hereinafter, examples of the apparatus being applied to an ESS will be described to aid in understanding the invention.

[0054] Figure 3 This is a block diagram illustrating an ESS according to some embodiments of the present invention. (Reference) Figure 3 According to some embodiments, the ESS may include a battery BAT, multiple slave BMS 100, a master BMS 200, an energy management system (EMS) 300, and a power conversion system (PCS) 400.

[0055] A battery BAT may include one or more battery racks, and when multiple battery racks are provided, the multiple battery racks may be connected in series, in parallel, or in a series-parallel combination (but for ease of illustration, however, Figure 1 (Only one battery rack is shown). Each battery rack may include multiple battery modules M connected in series or parallel, and each battery module M may include multiple battery cells C connected in series or parallel. The battery BAT can be charged by power supplied from the power grid G ​​through PCS 400, and the power charged in the battery BAT can be supplied to the power grid G ​​through PCS 400.

[0056] Multiple BMS 100s can be provided to correspond one-to-one with multiple battery modules M. For example, each BMS 100 can monitor the state of its corresponding battery module M and can operate to control the corresponding battery module M or perform protection functions on the corresponding battery module M based on the monitoring results. For example, the BMS 100 can monitor the voltage, current, temperature, and state of charge (SoC) of the battery cells C included in the battery module M. The BMS 100 can further perform control operations such as equalization control, temperature control, and charge / discharge control of the battery cells C based on the monitoring results, or perform protection operations such as switching control to prevent over-discharge or over-charge. Each BMS 100 may include: an analog front-end (AFE) integrated circuit (IC) that monitors the state of the battery cells C and performs battery cell control operations based on the monitoring results; and a microcontroller unit (MCU) that generates control operation commands or protection operation commands based on the state data of the battery cells C transmitted from the AFE IC, and feeds the control operation commands or protection operation commands to the AFE IC, thereby enabling the AFE IC to perform the control operation or protection operation. BMS 100 can correspond to the BMS module of the ESS and can correspond to the slave processor described in the claims of this application.

[0057] The master BMS 200 can perform battery rack control and protection functions based on status data of individual battery cells C or battery modules M received from multiple slave BMS 100s. The master BMS 200 can control the operation of each slave BMS 100 and can act as the master device for the slave BMS 100s. The master BMS 200 may include an MCU, which generates control operation commands or protection operation commands based on the status data of individual battery cells C or battery modules M transmitted from each slave BMS 100, and feeds these commands back to the slave BMS 100s, thereby enabling the slave BMS 100s to perform control or protection operations on each battery module M. The master BMS 200 may correspond to an ESS rack BMS and may correspond to the main processor described in the claims of this application. The master BMS 200 and multiple slave BMS 100s can be daisy-chained for communication, and isolated serial peripheral interface (isoSPI) or controller area network (CAN) communication can be used as communication methods.

[0058] Under the control of EMS 300, PCS 400 can be used as a power conversion device to perform AC-DC conversion, voltage level regulation, and frequency conversion to establish a power link between battery BAT and the power grid G. For example, when battery BAT is charging, PCS 400 can convert commercial AC voltage from the power grid G ​​to DC voltage, and when battery BAT is discharging, PCS 400 can convert DC voltage from battery BAT to commercial AC voltage. Furthermore, in an example where the ESS according to some embodiments is implemented as a frequency regulation ESS, when the frequency of the power grid G ​​drops below a preset reference value, PCS 400 can perform the function of supplying power to the power grid G ​​by discharging according to a set speed regulation rate under the frequency droop control of EMS 300. When the frequency of the power grid G ​​rises above the reference value, PCS 400 can perform the function of absorbing energy from the power grid G ​​by charging battery BAT, thereby maintaining the frequency stability of the power grid G.

[0059] The EMS 300 can be used as a higher-level controller than the main BMS 200 and PCS 400, and can serve as an integrated control device for real-time monitoring of the power consumption of the power grid G ​​and the power supply of the ESS, as well as controlling the operation of the ESS. The EMS 300 can monitor the status of the battery BAT, the main BMS 200, and the PCS 400, and control the operation of the main BMS 200 and PCS 400 based on the monitoring results. Transmission Control Protocol / Internet Protocol (TCP / IP) can be used as the communication protocol between the EMS 300 and the main BMS 200.

[0060] Figure 4 This is a circuit diagram illustrating an apparatus (hereinafter referred to as the apparatus) for analyzing the impedance characteristics of a battery according to some embodiments of the present invention. Figure 5 This is an example diagram illustrating the Nyquist plot of the impedance characteristics of a battery according to some embodiments of the present invention. Figure 4 The device shown is part of ESS.

[0061] like Figure 4 As shown, the device may include multiple slave processors 100, a master processor 200, a charge / discharge path PATH_CD, a current sensing element SR, a charge / discharge switch SW_CD (also simply referred to as a switch), and a switch driver SDRV. The master processor 200 and slave processors 100 correspond to the same components as the master BMS 200 and slave BMS 100 described above, respectively, and their basic operation has been described above, so a detailed description of their operation will not be repeated here.

[0062] The charge / discharge path PATH_CD can be used as a path to supply charging current and extract discharging current relative to the battery BAT. That is, when the battery BAT is charging, the charging current is supplied to the battery BAT through the charge / discharge path PATH_CD, and when the battery BAT is discharging, the discharging current is supplied to the load or the power grid through the charge / discharge path PATH_CD.

[0063] The current sensing element SR can correspond to a shunt resistor connected to the charge / discharge path PATH_CD to detect the current flowing through PATH_CD. The charge / discharge switch SW_CD can correspond to a relay or transistor (e.g., a metal-oxide-semiconductor field-effect transistor (MOSFET)) that allows or prevents the flow of current (i.e., the flow of charging or discharging current) on PATH_CD, and the switch driver SDRV can correspond to a gate driver that controls the on / off operation of the charge / discharge switch SW_CD under the control of the main processor 200. The main processor 200 can detect overcurrent through the current sensing element SR and control the switch driver SDRV to control the on / off operation of the charge / discharge switch SW_CD based on the detection result. That is, the main processor 200 can operate to detect the state of overcurrent flowing to the battery BAT through the current sensing element SR and control the switch driver SDRV to disconnect the charge / discharge switch SW_CD, thereby preventing the battery BAT from burning out due to overcurrent.

[0064] The following description focuses on the configuration for performing EIS analysis using a method that generates an excitation current from the charging current used to charge the battery.

[0065] According to some embodiments, the main processor 200 can utilize the charging current I during the charging of the battery BAT. C When supplied via the charge / discharge path PATH_CD, the on / off operation of the charge / discharge switch SW_CD is controlled to generate an excitation current I from the charging current for deriving the impedance characteristics of the battery BAT. E To derive the impedance characteristics of the battery.

[0066] For example, the main processor 200 can control the on / off operation of the charge / discharge switch SW_CD according to the pulse width modulation (PWM) method to generate an excitation current in the form of PWM pulses. Specifically, the on / off operation of the charge / discharge switch SW_CD can be controlled to keep the excitation current within a set or predefined frequency range (also referred to as the frequency range). This frequency range is a verification target for the impedance characteristics of the battery BAT and can be predefined, for example, as a range of 0.1 kHz to 5 kHz. Figure 5(ω1 to ω2 in the above). The main processor 200 can control the on / off operation of the charge / discharge switch SW_CD while changing the PWM control duty cycle, so that the excitation current has the frequency range defined above (the PWM control duty cycle corresponding to the set or predefined frequency range can also be predefined in the main processor 200).

[0067] When a PWM pulse-type excitation current within the frequency range is applied to the battery, the processor 100 can obtain the battery's voltage characteristic parameters and transmit them to the main processor 200. The main processor 200 can deduce the battery's impedance characteristics based on the battery's voltage characteristic parameters obtained from the processor 100 and the excitation current's current characteristic parameters obtained from the current sensing element SR.

[0068] Because the excitation current has a set or predefined frequency range, the battery voltage obtained from the processor 100 can also be in the form of AC voltage. Accordingly, the battery's voltage characteristic parameters can be parameterized as V. (ω) The voltage value of the battery according to the frequency is expressed in the form of I. The current characteristic parameter of the excitation current can also be parameterized as I. (ω) The form ω represents the value of the excitation current according to the frequency. Here, ω is the symbol for the frequency.

[0069] The main processor 200 can derive the frequency-dependent impedance characteristics of the battery based on voltage and current characteristic parameters. The main processor 200 can derive the battery's impedance characteristics as the ratio of voltage characteristic parameters to current characteristic parameters (i.e., Vimpedance). (ω) / I (ω) Furthermore, the impedance characteristics of the battery can have, for example... Figure 5 The Nyquist diagram shown is in the form of [example diagram].

[0070] When deriving the impedance characteristics of a battery in the form of a Nyquist plot, the main processor 200 can analyze battery aging by comparing the battery's impedance value at the target analysis frequency with a set or predefined reference impedance value (also referred to as the reference impedance value) at the target analysis frequency. The reference impedance value can be predefined (e.g., pre-stored) in the main processor 200 as the battery's impedance value at the target analysis frequency based on a non-aged state. Accordingly, the main processor 200 derives the battery's impedance value from the Nyquist plot at the target analysis frequency, which serves as the impedance value verification target. Furthermore, when the derived battery impedance value is greater than or equal to the reference impedance value, the main processor 200 can determine that the battery has aged.

[0071] The battery impedance derivation operation described above is performed while the battery is being charged by the charging current supplied through the charge / discharge path PATH_CD, and a constant current-constant voltage (CC-CV) method can be used as the battery charging method. As described above, due to the current control operation that generates an excitation current from the charging current by controlling the on / off operation of the charge / discharge switch SW_CD, the main processor 200 can derive the battery impedance characteristics in CV mode, where current control is possible in both CC and CV modes. In such an example, to reduce (e.g., minimize) the impact of the battery impedance derivation operation on the battery charging operation, the main processor 200 can control the on / off operation of the charge / discharge switch SW_CD to generate the excitation current at a point in time after a set time or predefined time has elapsed since the CV mode was started, and the length of the set time or predefined time can be greater than or equal to half of the total time during which the CV mode is executed. That is, the main processor 200 can perform the battery impedance derivation operation at the end of the CV mode, thereby reducing (e.g., minimizing) the impact of the battery impedance derivation operation on the battery charging operation.

[0072] Since the voltage characteristic parameters of the battery used in deriving the battery's impedance characteristics are obtained from the slave processor 100, and the voltage of the individual battery cells C constituting each battery module M can be measured by the AFE IC included in the slave processor 100, the master processor 200 can use the voltage characteristic parameters and the current characteristic parameters of the excitation current obtained for each of the plurality of battery cells C to derive the battery's impedance characteristics for each of the plurality of battery cells C. Furthermore, since the voltage of the battery module M can be measured by the AFE IC included in the slave processor 100, the master processor 200 can use the voltage characteristic parameters and the current characteristic parameters of the excitation current obtained for each of the plurality of battery modules M to derive the battery's impedance characteristics for that battery module M.

[0073] Figure 6 This is a flowchart illustrating a method for analyzing the impedance characteristics of a battery according to some embodiments of the present invention. (Refer to...) Figure 6 This describes a method for analyzing the impedance characteristics of a battery according to some embodiments. Here, detailed descriptions of multiple parts that overlap with those described above are not repeated, and the following description will focus on time series structures.

[0074] First, when the charging current for charging the battery is supplied through the charging and discharging path PATH_CD, the main processor 200 controls the on / off operation of the charging and discharging switch SW_CD, thereby generating an excitation current from the charging current to derive the impedance characteristics of the battery (operation S100).

[0075] In operation S100, the main processor 200 controls the on / off operation of the charge / discharge switch SW_CD according to the PWM method to generate an excitation current in the form of PWM pulses within a set or predefined frequency range.

[0076] Next, the main processor 200 acquires the battery's impedance characteristics when the excitation current generated from the charging current is applied to the battery (operation S200).

[0077] In operation S200, the main processor 200 acquires the battery's voltage characteristic parameters when the excitation current generated from the charging current is applied to the battery, acquires the current characteristic parameters of the excitation current by providing a current sensing element SR on the charge / discharge path PATH_CD, and then derives the battery's impedance characteristics based on the voltage and current characteristic parameters. The voltage characteristic parameters represent the battery's voltage value according to frequency, and the current characteristic parameters represent the value of the excitation current according to frequency. Accordingly, in operation S200, the main processor 200 derives the battery's impedance characteristics according to frequency based on the voltage and current characteristic parameters. The battery's impedance characteristics may be in the form of a Nyquist plot.

[0078] Furthermore, in operation S200, the main processor 200 can use the voltage characteristic parameters and current characteristic parameters of the excitation current obtained for each of the multiple battery cells C to derive the impedance characteristics of the battery for each of the multiple battery cells C, or use the voltage characteristic parameters and current characteristic parameters of the excitation current for each of the multiple battery modules M to derive the impedance characteristics of the battery for that battery module M.

[0079] Subsequently, the main processor 200 can analyze battery aging by comparing the battery's impedance value at the target analysis frequency with a set or predefined reference impedance value at the target analysis frequency (operation S300).

[0080] The operations S100 to S300 described above are triggered at a time point after a set time or a predefined time has elapsed since the CV mode is started in the battery charging mode, and the length of the set time or predefined time can be greater than or equal to half of the total time of the CV mode execution during this period.

[0081] According to the present invention, by employing a method of analyzing the impedance characteristics of a battery by generating an excitation current within a specific frequency range from the charging current used to charge the battery, rather than using an excitation current extracted from the battery as the target of impedance analysis to analyze the battery impedance, the impedance characteristics of the battery can be accurately derived without reducing the battery's usable energy or causing heat generation in the peripheral circuitry.

[0082] The embodiments described herein can be implemented as, for example, methods or processes, devices, software programs, data streams, or signals. Although discussed in the context of a single type of implementation (e.g., discussed only as a method), the features discussed herein can also be implemented in other forms (e.g., devices or programs). The device can be implemented by suitable hardware, software, firmware, etc. The method can be implemented on a device such as a processor, which generally refers to a processing device including computers, microprocessors, integrated circuits, programmable logic devices, etc. Processors include communication devices such as computers, cellular phones, personal digital assistants (PDAs), and other devices that facilitate information communication between the device and the end user.

[0083] Although this disclosure has been described with reference to embodiments and accompanying drawings illustrating aspects of this disclosure, this disclosure is not limited thereto. Those skilled in the art to which this disclosure pertains can make various suitable modifications and variations within the scope of the technical spirit of this disclosure as defined by the claims and their equivalents.

Claims

1. An apparatus for analyzing the impedance characteristics of a battery, the apparatus comprising: A switch is configured to allow or prevent current from flowing along a path used to supply charging current to the battery or to extract discharging current from the battery; as well as The processor is configured to derive the impedance characteristics of the battery using a method of generating an excitation current from the charging current for deriving the impedance characteristics of the battery by controlling the on / off operation of the switch when the charging current for charging the battery is supplied via the path.

2. The apparatus according to claim 1, further comprising: A current sensing element is configured to detect the current flowing along the path. The processor is configured to derive the impedance characteristics of the battery based on the voltage characteristic parameters of the battery when the excitation current generated from the charging current is applied to the battery and the current characteristic parameters of the excitation current obtained by the current sensing element.

3. The apparatus according to claim 2, wherein, The processor is configured to control the on / off operation of the switch according to a pulse width modulation (PWM) method to generate the excitation current in the form of PWM pulses.

4. The apparatus according to claim 3, wherein, The processor is configured to control the on / off operation of the switch to keep the excitation current within a certain frequency range.

5. The apparatus according to claim 4, wherein: The voltage characteristic parameter represents the voltage value of the battery according to the frequency, and the current characteristic parameter represents the value of the excitation current according to the frequency; and The processor is configured to derive the impedance characteristics of the battery according to the frequency based on the voltage characteristic parameters and the current characteristic parameters.

6. The apparatus according to claim 5, wherein, The processor is configured to derive the impedance characteristics of the battery in the form of a Nyquist plot.

7. The apparatus according to claim 5, wherein, The processor is further configured to analyze battery aging by comparing the battery's impedance value at the target analysis frequency with a reference impedance value at the target analysis frequency.

8. The apparatus according to claim 2, wherein: The processor is configured to control the charging current of the battery according to a constant current-constant voltage principle; and The processor is configured to derive the impedance characteristics of the battery in constant voltage mode.

9. The apparatus according to claim 8, wherein, The processor is configured to control the on / off operation of the switch to generate the excitation current at a time point after a set time has elapsed since the constant voltage mode was started.

10. The apparatus according to claim 9, wherein, The duration of the set time is greater than or equal to half of the total time during which the constant pressure mode is executed.

11. The apparatus according to claim 2, wherein: The battery comprises multiple battery cells; and The processor that generates the excitation current is defined as a main processor, and the device further includes: The processor is configured to acquire the voltage characteristic parameters for each of the plurality of battery cells and transmit the voltage characteristic parameters to the main processor.

12. The apparatus according to claim 11, wherein, The main processor is configured to derive the impedance characteristics of the battery for each of the plurality of battery cells using the voltage characteristic parameters and the current characteristic parameters of the excitation current obtained for each of the plurality of battery cells.

13. The apparatus according to claim 11, wherein: The battery is formed by connecting multiple battery modules, including the multiple battery cells, in series, in parallel, or in a series-parallel combination. The slave processor includes multiple slave processors, each corresponding to one of the multiple battery modules; and The main processor and the plurality of slave processors are connected in a daisy chain.

14. An energy storage system, comprising: Battery; A switch is configured to allow or prevent current from flowing along a path used to supply charging current to the battery or to extract discharging current from the battery; as well as The battery management system is configured to derive the impedance characteristics of the battery using a method that generates an excitation current from the charging current for deriving the impedance characteristics of the battery by controlling the on / off operation of the switch when the charging current for charging the battery is supplied via the path.

15. A method for analyzing the impedance characteristics of a battery, the method comprising: The processor generates an excitation current from the charging current for deriving the impedance characteristics of the battery by controlling the on / off operation of a switch when the charging current for charging the battery is supplied via a path, wherein the path is used to supply the charging current to the battery or extract the discharging current from the battery, and the switch allows or prevents current from flowing along the path; and When the excitation current generated from the charging current is applied to the battery, the processor derives the impedance characteristics of the battery.

16. The method according to claim 15, wherein, In the derivation of the impedance characteristics, the processor is configured to: When the excitation current generated from the charging current is applied to the battery, the voltage characteristic parameters of the battery are obtained; The current characteristic parameters of the excitation current are obtained by a current sensing element provided along the path. and The impedance characteristics of the battery are derived based on the voltage characteristic parameters and the current characteristic parameters.

17. The method according to claim 16, wherein, In the generation of the excitation current, the processor is configured to control the on / off operation of the switch according to a pulse width modulation (PWM) method to generate the excitation current in the form of PWM pulses within a certain frequency range.

18. The method of claim 17, wherein: The voltage characteristic parameter represents the voltage value of the battery according to the frequency, and the current characteristic parameter represents the value of the excitation current according to the frequency; and In the derivation of the impedance characteristics, the processor is configured to derive the impedance characteristics of the battery according to the frequency based on the voltage characteristic parameters and the current characteristic parameters.

19. The method of claim 18, further comprising: The processor analyzes the aging of the battery by comparing the impedance value of the battery at the target analysis frequency with a reference impedance value at the target analysis frequency.

20. The method of claim 16, wherein: The charging current charges the battery according to a constant current-constant voltage principle; and The generation of the excitation current and the derivation of the impedance characteristics are triggered at a time point after a set time has elapsed since the constant voltage mode was started.

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