Battery diagnostic device, and operation method therefor

Abstract

According to an embodiment disclosed in the present document, a battery diagnostic device may comprise: an information acquisition unit for acquiring current and voltage data of each of a plurality of battery cells; and a controller for determining a target section on the basis of the current of the battery cell, and using the voltage data of each of the plurality of battery cells corresponding to the target section to calculate the value of at least one parameter constituting an equivalent circuit model, and diagnosing the state of each of the plurality of battery cells on the basis of the value of the at least one parameter.

Description

Battery diagnostic device and its operating method

[0001] Cross-citation with related applications

[0002] The embodiments disclosed in this document claim the benefit of priority based on Korean Patent Application No. 10-2023-0074764, filed on June 12, 2023, which is incorporated herein by reference in its entirety.

[0003] Technology field

[0004] The embodiments disclosed in this document relate to a battery diagnostic device and an operating method thereof.

[0005] Recently, research and development on secondary batteries has been actively conducted. Here, secondary batteries are rechargeable and include both conventional Ni / Cd and Ni / MH batteries, as well as recent lithium-ion batteries. Among secondary batteries, lithium-ion batteries have the advantage of having a much higher energy density than conventional Ni / Cd and Ni / MH batteries. Furthermore, lithium-ion batteries can be manufactured in a compact and lightweight form, making them suitable for use as power sources for mobile devices. Recently, their use has expanded to include power sources for electric vehicles, attracting attention as a next-generation energy storage medium.

[0006] Battery defects, such as short circuits, exposed cathodes, and lithium deposition, in battery cells within a battery pack can pose a risk of fire. Therefore, early detection and action are crucial to prevent fires. When diagnosing the condition of batteries in use, non-destructive testing has been primarily used to minimize changes in battery condition, or the battery's response to external pulses has been assessed. However, these methods primarily assess battery degradation rather than actual defects, making it difficult to quickly diagnose defective cells in batteries in use.

[0007] One purpose of the embodiments disclosed in this document is to provide a battery diagnostic device and an operating method thereof that can diagnose a defect in a battery cell within a short period of time even while the battery pack is in use.

[0008] One purpose of the embodiments disclosed in this document is to provide a battery diagnostic device and an operating method thereof that can diagnose whether a specific type of failure has occurred by determining a diagnostic section according to the type of failure to be diagnosed.

[0009] The technical problems of the embodiments disclosed in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the descriptions below.

[0010] According to an embodiment disclosed in this document, a battery diagnosis device may include an information acquisition unit that acquires current and voltage data of each of a plurality of battery cells, a controller that determines a target section based on the current of each of the plurality of battery cells, calculates a value of at least one parameter constituting an equivalent circuit model using voltage data of each of the plurality of battery cells corresponding to the target section, and diagnoses a state of each of the plurality of battery cells based on the value of the at least one parameter.

[0011] According to an embodiment, the controller may determine a section in which the current of each of the plurality of battery cells continues in a discharge state for a preset period of time or longer as the target section.

[0012] According to an embodiment, the controller may divide the target section into a plurality of sections based on the equivalent circuit model, and determine at least one of the plurality of sections as an analysis section based on a type of defect to be diagnosed.

[0013] According to an embodiment, the controller can divide the target section into a plurality of sections based on the correlation between the parameters constituting the equivalent circuit model and the voltage.

[0014] According to an embodiment, when the type of defect to be diagnosed is a defect at an electrode interface, the controller may determine, as the analysis section, a section related to a resistance component that considers the influence of ions moving between the electrode interface and an electrolyte solution and a capacitor component that considers the storage effect due to charges of opposite polarity at the electrode interface.

[0015] According to an embodiment, the controller may determine a cell among the plurality of battery cells whose parameter value associated with the analysis section exceeds a threshold value as defective.

[0016] According to an embodiment, the threshold value may be set based on the parameter value of each of the plurality of battery cells.

[0017] According to an embodiment, the equivalent circuit model may include a Randles model or a 2RC model.

[0018] According to an embodiment, the controller can calculate a value of the at least one parameter by fitting voltage data of each of the battery cells corresponding to the target section to the equivalent circuit model.

[0019] According to an embodiment disclosed in the present document, a battery diagnosis method may include a step of obtaining current and voltage data of each of a plurality of battery cells, a step of determining a target section based on the current of each of the plurality of battery cells, a step of calculating a value of at least one parameter constituting an equivalent circuit model using voltage data of each of the plurality of battery cells corresponding to the target section, and a step of diagnosing a state of each of the plurality of battery cells based on the value of the at least one parameter.

[0020] According to an embodiment, the step of determining the target section may be characterized by determining a section in which the current of each of the plurality of battery cells continues in a discharge state for a preset period of time or longer as the target section.

[0021] According to an embodiment, the battery diagnosis method may further include a step of dividing the target section into a plurality of sections based on the equivalent circuit model; and a step of determining at least one of the plurality of sections as an analysis section based on a type of defect to be diagnosed.

[0022] According to an embodiment, the step of dividing the target section into a plurality of sections may be characterized by dividing the target section into a plurality of sections based on a correlation between parameters constituting the equivalent circuit model and voltage.

[0023] According to an embodiment, the step of determining at least one of the plurality of sections as an analysis section may be characterized in that, when the type of defect to be diagnosed is a defect at an electrode interface, a section related to a resistance component that considers the influence of ions moving between the electrode interface and an electrolyte solution and a capacitor component that considers the storage effect due to charges of opposite polarity at the electrode interface is determined as the analysis section.

[0024] According to an embodiment, the step of diagnosing the status of the plurality of cells may be characterized by determining a cell among the plurality of battery cells whose parameter value associated with the analysis section exceeds a threshold value as defective.

[0025] The battery diagnostic device and its operating method according to the embodiments disclosed in this document can diagnose whether a battery is defective in a short period of time.

[0026] The battery diagnostic device and its operating method according to the embodiments disclosed in this document can diagnose battery cells in a diversified manner according to the type of defect.

[0027] In addition, various effects may be provided, either directly or indirectly, through this document.

[0028] Figure 1 is a block diagram showing the configuration of a typical battery pack.

[0029] FIG. 2 is a block diagram showing a battery diagnostic device according to one embodiment disclosed in this document.

[0030] FIGS. 3A to 3C are diagrams showing examples of a series of processes for performing equivalent circuit model fitting according to one embodiment disclosed in the present document.

[0031] FIG. 4a is a diagram showing an example of an equivalent circuit model according to one embodiment disclosed in this document.

[0032] Figure 4b is a drawing showing an example of dividing a target section into multiple sections.

[0033] FIG. 5 is a diagram showing an example of diagnosing a defective cell and parameter values ​​of each battery cell according to one embodiment disclosed in this document.

[0034] FIG. 6 is a flowchart illustrating a battery diagnosis method according to one embodiment disclosed in this document.

[0035] FIG. 7 is a block diagram showing the hardware configuration of a computing system for performing an operating method of a battery management device according to one embodiment disclosed in this document.

[0036] Hereinafter, various embodiments of the present invention will be described with reference to the attached drawings. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that the present invention encompasses various modifications, equivalents, and / or alternatives of the embodiments.

[0037] In this document, the singular form of a noun corresponding to an item may include one or more of said items, unless the context clearly indicates otherwise. In this document, phrases such as "A or B," "at least one of A and B," "at least one of A or B," "A, B, or C," "at least one of A, B, and C," and "at least one of A, B, or C" may each include any one of the items listed together in that phrase, or all possible combinations thereof. Terms such as "first," "second," or "first" or "second" may be used merely to distinguish the corresponding element from other corresponding elements, and do not limit the corresponding elements in any other respect (e.g., importance or order). When a component (e.g., a first component) is referred to as being “coupled” or “connected” to another component (e.g., a second component), with or without the terms “functionally” or “communicatively,” it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

[0038] Each component (e.g., a module or a program) described in this document may include one or more entities. According to various embodiments, one or more components or operations of the components may be omitted, or one or more other components or operations may be added. Alternatively or additionally, a plurality of components (e.g., a module or a program) may be integrated into a single component. In such a case, the integrated component may perform one or more functions of each of the plurality of components identically or similarly to those performed by the corresponding component among the plurality of components prior to integration. According to various embodiments, the operations performed by a module, program, or other component may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

[0039] The term "module" or "part" used in this document may include a unit implemented in hardware, software, or firmware, and may be used interchangeably with terms such as logic, logic block, component, or circuit. A module may be an integral component, or a minimum unit or part of such a component that performs one or more functions. For example, according to one embodiment, a module may be implemented in the form of an application-specific integrated circuit (ASIC).

[0040] Various embodiments of the present document may be implemented as software (e.g., a program or an application) including one or more instructions stored in a machine-readable storage medium (e.g., memory). For example, a processor of the device may call at least one instruction among the one or more instructions stored from the storage medium and execute it. This enables the device to operate to perform at least one function according to the at least one instruction called. The one or more instructions may include code generated by a compiler or code executable by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Here, "non-transitory" only means that the storage medium is a tangible device and does not contain a signal (e.g., electromagnetic waves), and this term does not distinguish between cases where data is stored semi-permanently and cases where it is stored temporarily in the storage medium.

[0041]

[0042] Figure 1 is a block diagram showing the configuration of a typical battery pack.

[0043] Referring to FIG. 1, a battery control system including a battery pack (1) and an upper controller (2) included in an upper system according to one embodiment of the present invention is schematically illustrated.

[0044] As illustrated in FIG. 1, a battery pack (1) is composed of one or more battery cells and includes a plurality of battery cells (10) that are rechargeable and dischargeable, a switching unit (14) that is connected in series to the (+) terminal side or the (-) terminal side of the plurality of battery cells (10) to control the flow of charge and discharge current of the plurality of battery cells (10), and a battery management system (20) that monitors the voltage, current, temperature, etc. of the battery pack (1) and controls and manages to prevent overcharging and overdischarging, etc. In this case, the battery pack (1) may be equipped with a plurality of battery cells (10), sensors (12), switching units (14), and battery management systems (20).

[0045] Here, the switching unit (14) is a device for controlling the current flow for charging or discharging of a plurality of battery cells (10), and for example, at least one relay, magnetic contactor, etc. may be used depending on the specifications of the battery pack (1).

[0046] The battery management system (20) is an interface that receives values ​​measured from the various parameters described above, and may include a plurality of terminals and a circuit that is connected to the terminals and processes the values ​​received. In addition, the battery management system (20) may control the ON / OFF of a switching unit (14), for example, a relay or a contactor, and may be connected to a plurality of battery cells (10) and monitor the status of each of the plurality of battery cells (10). According to an embodiment, the battery management system (20) may include the battery management device (100) of FIG. 2. According to another embodiment, the battery management system (20) may be a different system from the battery management device (100) of FIG. 2. That is, the battery management device (100) of FIG. 2 may be included in the battery pack (1) or may be configured as another device external to the battery pack (1). In addition, the operation of the battery management device (100) below can be performed by a BMS (Battery Management System) in a vehicle, as well as by various devices such as a server, cloud, charger, or charger / discharger.

[0047] The upper controller (2) can transmit control signals for multiple battery cells (10) to the battery management system (20). Accordingly, the battery management system (20) can be controlled in operation based on the signals received from the upper controller (2).

[0048] FIG. 2 is a block diagram showing a battery diagnostic device according to one embodiment disclosed in this document.

[0049] Referring to FIG. 2, a battery diagnostic device (100) according to one embodiment disclosed in the present document may include an information acquisition unit (110) and a controller (120). Depending on the embodiment, the battery diagnostic device (100) may be included in the battery management system (20) of FIG. 1, or may be another device different from the battery management system (20) of FIG. 1.

[0050] The battery diagnostic device (100) can diagnose defective cells based on the voltage behavior of battery cells in an environment where current can be applied without disassembling the battery pack. Furthermore, the battery diagnostic device (100) can diagnose defective cells in real time by extracting parameters through self-vibration even in a situation where a separate external power source is not connected in a vehicle equipped with the battery pack. In particular, since the battery diagnostic device (100) can perform a diagnosis at any time as long as it secures a sufficient amount of data to extract parameters of an equivalent circuit model, it can diagnose defective cells in a short period of time.

[0051] The information acquisition unit (110) can acquire current and voltage data for each of a plurality of battery cells. For example, the information acquisition unit (110) can acquire current and voltage data for each battery cell for a specific period of time to check current and voltage behavior. In an embodiment, the current data acquired from the information acquisition unit (110) can be used to determine a target section for diagnosing defective cells, and the voltage data can be used to determine whether each battery cell is defective in the determined target section. In addition, the information acquisition unit (110) can further acquire cell-related data, such as temperature, SOH, and SOC of each battery cell.

[0052] The controller (120) can determine a target section based on the current of each battery cell. The target section may be a section for diagnosing each battery cell, and may be determined as the same section for multiple cells. The target section may be a portion of the entire period during which the information acquisition unit (110) acquires data on the battery cells.

[0053] Each battery cell may be connected in series and / or in parallel within the battery pack. At this time, even if the current value of each battery cell is different, the current behavior may be the same. The controller (120) may determine a target section for diagnosing each battery cell based on the current behavior of each battery cell. For example, in the charging section of the battery pack, the current value of each battery cell may all have a positive (+) value, and in the discharging section of the battery pack, the current value of each battery cell may all have a negative (-) value. At this time, the controller (120) may determine the point after the point at which the current behavior of each battery cell equally switches from positive (+) to negative (-) (i.e., switches from the charging section to the discharging section) as the target section.

[0054] The controller (120) can calculate the value of at least one parameter constituting an equivalent circuit model using voltage data of each of a plurality of battery cells corresponding to a target section. The controller (120) can extract voltage data corresponding to the target section from among the voltage data acquired for each battery cell, and calculate the value of at least one parameter using the extracted voltage data. In an embodiment, the controller (120) can calculate the parameter value by fitting the voltage data of each of the battery cells corresponding to the target section to an equivalent circuit model. Here, fitting the equivalent circuit model may mean configuring an electric circuit that simulates voltage behavior according to current, time, etc. of the battery cell.

[0055] The controller (120) can diagnose the status of each of the plurality of battery cells based on at least one parameter value. The controller (120) can diagnose whether each battery cell is defective based on the parameter value calculated for each battery cell. For example, the controller (120) can determine that the battery cell is defective if the value of the parameter calculated for a specific battery cell does not fall within a reference range or if the deviation from the average parameter value of the plurality of battery cells is greater than a reference value.

[0056] According to an embodiment, the controller (120) may determine as a target section a section in which the current of the battery cell continues in a discharged state for a preset period of time. The controller (120) may set as a target section a section in which the current of the battery cell is in a discharged state so that diagnosis of the battery cell can be performed even when the battery cell is not connected to an external device, for example, while driving a vehicle. In addition, the controller (120) may determine as a target section a section in which the discharge current of each battery cell continues for a preset period of time of 1 C (crate) or more to ensure the reliability of the data of each battery cell and the accuracy of the equivalent circuit model fitting. In other words, the preset time may be determined as a time for securing data sufficient to ensure the reliability and accuracy of the equivalent circuit model fitting.

[0057] In an embodiment, the controller (120) may set the target section to a section corresponding to pulse application from the external device when the battery pack is connected to an external device (e.g., a charging device) to perform a diagnosis.

[0058] According to an embodiment, the controller (120) can divide the target section into multiple sections based on an equivalent circuit model. The equivalent circuit model can include various circuit models such as the Randles model and the nRC model (where n is a natural number), and the parameters included in each equivalent circuit model can be different. Accordingly, the controller (120) can divide the target section into multiple sections based on the equivalent circuit model.

[0059] According to an embodiment, the controller (120) may divide the target section into a plurality of sections based on the correlation between the parameters constituting the equivalent circuit model and the voltage. The parameters included in the equivalent circuit model may have different correlations with the voltage behavior of the battery cell depending on the characteristics of each parameter. For example, a battery pack may include an electrolyte solution, and the resistance of the electrolyte solution itself may affect the voltage behavior of the battery cell. In this case, the resistance of the electrolyte solution may be expressed as a series resistance component of the equivalent circuit model. That is, an independent series resistance component in the equivalent circuit model may be related to the 'resistance of the electrolyte solution' with respect to the voltage of the battery cell. In this way, each parameter of the equivalent circuit model may have different correlations with the voltage of the battery cell, and the controller (120) may divide the target section based on the correlation of the parameters with the voltage.

[0060] According to an embodiment, the controller (120) may determine at least one of a plurality of sections as an analysis section based on the type of defect to be diagnosed. The type of defect in the cell may include various types, such as electrode interface defects, terminal contact defects, lithium deposition, etc., and the abnormal form of voltage behavior and the section in which such an abnormality occurs may vary depending on the type of defect. Accordingly, the controller (120) may determine an analysis section among a plurality of sections based on the type of defect to be diagnosed.

[0061] The controller (120) can diversify the diagnosis of defective cells by setting different analysis sections according to various types of defects or correlations to be intensively examined through determination of the analysis section.

[0062] According to an embodiment, if the type of defect to be diagnosed is a defect at the electrode interface, the controller (120) may determine, as the analysis section, a section related to a resistance component that considers the influence of ion movement between the electrode interface and the electrolyte solution and a capacitor component that considers the storage effect due to opposite polarity charges at the electrode interface. The battery pack may include an electrolyte solution and electrodes (anode and cathode), and an electrochemical reaction occurring at the interface between the electrode and the electrolyte solution may affect the voltage and / or current of the battery cell.

[0063] For example, at an electrode interface, charges with opposite polarity to the electrode may gather at the interface, thereby forming a charge distribution similar to a capacitor, and at this time, a capacitive effect similar to a capacitor may be exhibited due to these opposite polarity charges. This capacitive effect may be expressed as a condenser component in an equivalent circuit model. In addition, the influence of the activation energy, reaction rate, etc. of the reaction in the redox reaction through the diffusion of ions or the transfer of electrons at the electrode interface may be expressed as a resistance component connected in parallel with the condenser component in the equivalent circuit model. In this way, the controller (120) sets the analysis section by considering electrochemical theory and phenomena according to the type of defect, thereby enabling more accurate and detailed defect diagnosis.

[0064] According to an embodiment, the controller (120) may determine a cell among a plurality of battery cells in which a parameter value associated with an analysis section exceeds a threshold value as defective. For example, if the defective type is a defect at an electrode interface, the fact that a capacitor component due to the opposite polarity is above the threshold value may be determined to mean that a large number of opposite polarity charges exist at the electrode interface, thereby affecting the voltage and / or current behavior of the battery cell beyond the normal range, and the controller (120) may diagnose the corresponding battery cell as defective.

[0065] According to an embodiment, a threshold value may be set based on the parameter values ​​of each of the plurality of battery cells. The controller (120) may set the threshold value as an absolute reference value or as a relative reference value through comparison of each battery cell. The absolute reference value may be set statistically or experimentally, and may be set based on a reference range of parameter values ​​typically calculated when the battery cell is normal. For example, the controller (120) may calculate an average value of each battery cell for the same parameter, and set the threshold value based on the calculated average value. In another example, the controller (120) may normalize the parameter values ​​of each battery cell, and set a value at which the standard deviation of the normalized parameter is greater than or equal to a preset level as the threshold value. For example, the threshold value may be set to 0.65.

[0066] In this way, the controller (120) can individually diagnose whether a cell is abnormal by calculating a parameter value associated with the analysis section for each battery cell. In an embodiment, the controller (120) can determine that the battery pack is defective or requires a precise diagnosis if the number of cells determined to be defective in the battery pack is greater than or equal to a preset number or a preset ratio. For example, if the number of cells determined to be defective out of the total number of battery cells included in the battery pack as a result of the diagnosis of each battery cell is greater than or equal to a preset ratio, the controller (120) can determine that the battery pack (1) is a target for a precise diagnosis.

[0067] In addition, if the diagnosis results confirm that the battery cell is defective, the controller (120) can provide information about the defective battery cell to the user. For example, the controller (120) can provide information about the defective battery cell to the user terminal via a communication unit (not shown), and can also provide information about the defective battery cell via a display provided in a vehicle or charger.

[0068] Conversely, if there is no battery cell judged to be defective for a defect type, the controller (120) can determine that the battery pack and each battery cell have not experienced the defect type, and can perform a diagnosis for another defect type.

[0069] FIGS. 3A to 3C are diagrams showing examples of a series of processes for performing equivalent circuit model fitting according to one embodiment disclosed in the present document.

[0070] FIG. 3a shows an example of current and voltage data of each battery cell acquired by the information acquisition unit (110), FIG. 3b shows an example of voltage data of each battery cell in the target section, and FIG. 3c shows an example of the result of fitting the voltage data of each battery cell in the target section to an equivalent circuit model.

[0071] Referring to Fig. 3a, the information acquisition unit (110) can acquire voltage data (310) and current data (320) of each battery cell. In Fig. 3a, the voltage data (310) can include voltage data (CV1, CV2, CV3) for three battery cells. In addition, Fig. 3a exemplifies a situation where three battery cells are connected in series, and the current data of each battery cell can be the same.

[0072] The controller (120) can determine a target section based on the current data (320) of the battery cell. In Fig. 3a, the target section can represent a circular section represented by a dotted line.

[0073] The controller (120) can extract voltage data (330) of each battery cell in the target section as shown in FIG. 3b. The voltage data (330) may be part of the voltage data (310).

[0074] The controller (120) can fit the voltage data (340) of each battery cell in the target section to an equivalent circuit model. The voltage data (340) in FIG. 3c may be substantially identical to the voltage data (330) in FIG. 3b. Reference numeral 350 in FIG. 3c may represent voltage behavior according to the equivalent circuit model.

[0075] FIG. 4a is a diagram showing an example of an equivalent circuit model according to one embodiment disclosed in this document. FIG. 4b is a diagram showing an example of dividing a target section into multiple sections.

[0076] Fig. 4a shows an example of the Randles model among equivalent circuit models. Referring to Fig. 4 (a), the Randles model is an independent series resistance component ( ), condenser components connected in parallel ( ), parallel resistance component ( ) and impedance components ( ) can be included. In the Randles model, the series resistance component ( ) can be related to the resistance of the electrolyte in the battery pack, and the capacitor component ( ) may be associated with the capacitive effect due to charges of opposite polarity at the electrode interface, and the parallel resistance component ( ) may be associated with the effect of ion migration between the electrode interface and the electrolyte solution, and the impedance component ( ) may be associated with the effect of ion diffusion between the electrode interface and the electrolyte solution.

[0077] Fig. 4b shows an example of dividing the target section into multiple sections. For example, if the equivalent circuit model is the Randles model, the controller (120) can divide the target section into four sections as shown in Fig. 4b. The controller (120) can divide the target section based on the correlation between the parameters constituting the equivalent circuit model and the voltage behavior. For example, section 1 in Fig. 4b is the series resistance component of the Randles model ( ) may be related to the section, and the third section is the parallel resistance component ( ) and condenser components ( ) may be associated with.

[0078] For example, if the type of defect to be diagnosed is a defect at the electrode interface, the controller (120) may determine section 3 among the target sections as the analysis section. At this time, the parameter that serves as the standard for diagnosing each battery cell as defective is the parallel resistance component ( ) and condenser components ( ) may be.

[0079] FIG. 5 is a diagram showing an example of diagnosing a defective cell and parameter values ​​of each battery cell according to one embodiment disclosed in this document.

[0080] Figure 5 (a) shows the parameter values ​​derived from the equivalent circuit model fitting of each battery cell. Figure 5 (a) shows the parameter values ​​for a total of 18 cells. Figure 5 (a) may be the result of fitting an equivalent circuit model including 6 parameters.

[0081] Figure 5 (b) shows an example of diagnosing a defective cell based on a parameter value. Figure 5 (b) shows that a defective cell is diagnosed based on the value of parameter 6 when the parameter associated with the analysis section is parameter 6. The controller (120) can diagnose a cell in which the value of parameter 6 exceeds a threshold value as a defective cell.

[0082] The number of parameters and the number of battery cells shown in Fig. 5 are only examples and are not limited thereto.

[0083] FIG. 6 is a flowchart illustrating a battery diagnosis method according to one embodiment disclosed in this document.

[0084] Referring to FIG. 6, the battery diagnosis method may include a step of obtaining current and voltage data of each of a plurality of battery cells (S100), a step of determining a target section based on the current of each of the plurality of battery cells (S200), a step of calculating a value of at least one parameter constituting an equivalent circuit model using voltage data of each of the plurality of battery cells corresponding to the target section (S300), and a step of diagnosing a state of each of the plurality of battery cells based on the value of the at least one parameter (S400).

[0085] In step S100, the information acquisition unit (110) can acquire current and voltage data of each of the plurality of battery cells. The information acquisition unit (110) can also acquire cell-related data, such as temperature, SOH, and SOC of each battery cell.

[0086] At step S200, the controller (120) can determine a target section based on the current of each of the plurality of battery cells. For example, the controller (120) can determine a section in which the discharge current of a battery cell continues in a discharge state for a preset period of time or longer as a target section.

[0087] At step S300, the controller (120) can calculate the value of at least one parameter constituting an equivalent circuit model using voltage data of each of a plurality of battery cells corresponding to the target section. The equivalent circuit model can include at least one of the Randles model and the 2RC model. The controller (120) can calculate the value of at least one parameter by fitting the voltage data corresponding to the target section to the equivalent circuit model.

[0088] In an embodiment, the controller (120) may divide the target section into multiple sections based on an equivalent circuit model. The controller (120) may determine at least one of the multiple sections as an analysis section.

[0089] At step S400, the controller (120) can diagnose the status of each of the plurality of battery cells based on the value of at least one parameter. For example, the controller (120) can determine that a cell whose parameter value associated with the analysis section exceeds a threshold value is defective.

[0090] FIG. 7 is a block diagram showing the hardware configuration of a computing system for performing an operating method of a battery management device according to one embodiment disclosed in this document.

[0091] Referring to FIG. 7, a computing system (1000) according to one embodiment disclosed in the present document may include an MCU (1010), a memory (1020), an input / output I / F (1030), and a communication I / F (1040).

[0092] The MCU (1010) may be a processor that executes various programs stored in the memory (1020) (e.g., a battery cell current and voltage data collection program, a target section determination program, an equivalent circuit model configuration program, a parameter calculation program, a battery cell diagnosis program, etc.), processes various information including battery cell current, voltage, and parameters through these programs, and performs the functions of the controller included in the battery management device shown in FIG. 2 described above.

[0093] The memory (1020) can store various programs, such as a battery cell current and voltage data collection program, a target section determination program, an equivalent circuit model configuration program, a parameter calculation program, and a battery cell diagnosis program. In addition, the memory (1020) can store various information, including the battery cell's SOC, OCV, and parameters.

[0094] Such memories (1020) may be provided in multiple numbers as needed. The memories (1020) may be volatile memories or non-volatile memories. As volatile memories (1020), RAM, DRAM, SRAM, etc. may be used. As non-volatile memories (1020), ROM, PROM, EAROM, EPROM, EEPROM, flash memories, etc. may be used. The examples of the memories (1020) listed above are merely examples and are not limited to these examples.

[0095] The input / output I / F (1030) can provide an interface that enables data transmission and reception between an input device (not shown) such as a keyboard, mouse, or touch panel, and an output device (not shown) such as a display and the MCU (1010).

[0096] The communication I / F (1040) is a component capable of transmitting and receiving various data with the server, and may be any device capable of supporting wired or wireless communication. For example, the battery management device can transmit and receive various information, including the SOC, OCV, and parameters of the battery cell, from a separately provided external server via the communication I / F (1040).

[0097] In this way, a computer program according to one embodiment disclosed in this document may be implemented as a module that is recorded in a memory (1020) and processed by an MCU (1010) to perform each function illustrated in FIG. 2, for example.

[0098]

[0099] Although all components constituting the embodiments disclosed in this document have been described as being combined or operating in combination as one, the embodiments disclosed in this document are not necessarily limited to such embodiments. That is, within the scope of the purpose of the embodiments disclosed in this document, all of the components may be selectively combined and operated one or more times.

[0100] In addition, terms such as "include," "comprise," or "have" described above, unless specifically stated otherwise, mean that the corresponding component can be included, and therefore should be interpreted to include other components rather than excluding other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiments disclosed in this document belong, unless otherwise defined. Commonly used terms, such as terms defined in a dictionary, should be interpreted to be consistent with the contextual meaning of the relevant technology, and shall not be interpreted in an idealized or overly formal sense, unless explicitly defined in this document.

[0101] The above description is merely an example of the technical idea disclosed in this document, and those skilled in the art to which the embodiments disclosed in this document pertain may make various modifications and variations without departing from the essential characteristics of the embodiments disclosed in this document. Therefore, the embodiments disclosed in this document are not intended to limit the technical idea of ​​the embodiments disclosed in this document, but to explain it, and the scope of the technical idea disclosed in this document is not limited by these embodiments. The scope of protection of the technical idea disclosed in this document should be interpreted by the claims below, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of rights of this document.

Claims

1. An information acquisition unit that acquires current and voltage data of each of multiple battery cells; and Determine the target section based on the current of each of the plurality of battery cells, Calculating the value of at least one parameter constituting an equivalent circuit model using voltage data of each of the plurality of battery cells corresponding to the target section, A battery diagnostic device including a controller that diagnoses the status of each of the plurality of battery cells based on the value of at least one parameter.

2. In paragraph 1, The above controller, A battery diagnostic device that determines a section in which the current of each of the plurality of battery cells continues in a discharge state for a preset period of time or longer as the target section.

3. In paragraph 2, The above controller, Based on the above equivalent circuit model, the target section is divided into multiple sections, A battery diagnostic device that determines at least one of the plurality of sections as an analysis section based on the type of defect to be diagnosed.

4. In paragraph 3, The above controller, A battery diagnostic device that divides the target section into multiple sections based on the correlation between the parameters constituting the equivalent circuit model and the voltage.

5. In paragraph 4, The above controller, If the type of defect you want to diagnose is a defect at the electrode interface, A battery diagnostic device that determines the analysis section as a section related to a resistance component that takes into account the influence of ion movement between the electrode interface and the electrolyte solution and a capacitor component that takes into account the storage effect due to charges of opposite polarity at the electrode interface.

6. In paragraph 4, The above controller, A battery diagnostic device that determines a cell among the plurality of battery cells whose parameter value associated with the analysis section exceeds a threshold value as defective.

7. In paragraph 6, A battery diagnostic device, wherein the threshold value is set based on the parameter value of each of the plurality of battery cells.

8. In paragraph 1, A battery diagnostic device, wherein the equivalent circuit model includes a Randles model or a 2RC model.

9. In paragraph 1, The above controller, A battery diagnostic device that calculates the value of at least one parameter by fitting voltage data of each battery cell corresponding to the target section to the equivalent circuit model.

10. A step of acquiring current and voltage data of each of a plurality of battery cells; A step of determining a target section based on the current of each of the plurality of battery cells; A step of calculating the value of at least one parameter constituting an equivalent circuit model using voltage data of each of the plurality of battery cells corresponding to the target section; and A battery diagnosis method comprising a step of diagnosing the status of each of the plurality of battery cells based on the value of at least one parameter.

11. In paragraph 10, The step of determining the above target section is: A battery diagnosis method characterized in that a section in which the current of each of the plurality of battery cells continues in a discharge state for a preset period of time or longer is determined as the target section.

12. In paragraph 11, A step of dividing the target section into multiple sections based on the equivalent circuit model; and A battery diagnosis method further comprising a step of determining at least one of the plurality of sections as an analysis section based on the type of defect to be diagnosed.

13. In paragraph 12, The step of dividing the above target section into multiple sections is: A battery diagnosis method characterized in that the target section is divided into multiple sections based on the correlation between the parameters constituting the equivalent circuit model and the voltage.

14. In paragraph 13, The step of determining at least one of the above multiple sections as an analysis section is: A battery diagnostic device characterized in that, when the type of defect to be diagnosed is a defect at the electrode interface, the analysis section is determined to be a section related to a resistance component that takes into account the influence of ion movement between the electrode interface and the electrolyte solution and a capacitor component that takes into account the storage effect due to charges of opposite polarity at the electrode interface.

15. In paragraph 13, The step of diagnosing the status of the above multiple cells is: A battery diagnostic device characterized in that a cell among the plurality of battery cells whose parameter value associated with the analysis section exceeds a threshold value is judged to be defective.

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