Apparatus for managing battery and operating method of the same

Abstract

A battery management device according to an embodiment disclosed in this document may include: an acquisition unit for acquiring the voltage of a plurality of battery cells; and a controller for calculating a voltage profile regarding the voltage of each of the plurality of battery cells, calculating the slope of the voltage profile by linear fitting the voltage profile over a predetermined time interval, and diagnosing the state of each of the plurality of battery cells based on the slope of the voltage profile of each of the plurality of battery cells.

Description

Technology Field

[0001] The embodiments disclosed in this document relate to a battery management device and a method of operating the same. Background Technology

[0002] Recently, active research and development on secondary batteries has been underway. Here, secondary batteries are rechargeable batteries that can be interpreted to encompass conventional Ni / Cd and Ni / MH batteries, as well as recent lithium-ion batteries. With their scope of application expanding to include power sources for electric vehicles, they are garnering attention as a next-generation energy storage medium.

[0003] Electric vehicles generate power by receiving electricity from an external source to charge battery cells, and then discharging the cells to drive the motor. Defects can occur in battery cells during the production and usage stages. For example, structural defects (e.g., overhang) may occur during the production phase. Additionally, the physicochemical properties of the battery cells may change due to various charging and discharging cycles during usage. Therefore, technology is required to diagnose and manage battery cell abnormalities caused by production defects or degradation.

[0004] Charge and discharge tests on battery cells can be performed for various purposes, such as battery performance diagnosis and condition analysis. Based on the current and voltage obtained through the charge and discharge tests, the profile of the battery cell's Open Circuit Voltage (OCV) can be calculated. Furthermore, defects in the battery cell can be detected by analyzing the Open Circuit Voltage profile. The problem to be solved

[0005] One objective of the embodiments disclosed in this document is to provide a battery management device capable of diagnosing defects or degradation of each of a plurality of battery cells included in a battery cell pack, and a method of operating the same.

[0006] One objective of the embodiments disclosed in this document is to provide a battery management device capable of diagnosing a cell in which lithium plating has occurred among a plurality of battery cells included in a battery cell pack by a non-destructive method, and a method of operating the same.

[0007] The technical problems of the embodiments disclosed in this document are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0008] A battery management device according to an embodiment disclosed in this document includes: an acquisition unit for acquiring the voltage of a plurality of battery cells; and a controller for calculating the voltage gradient of the plurality of battery cells based on the voltage of the plurality of battery cells acquired in a predetermined time interval, and diagnosing the state of each of the plurality of battery cells based on the voltage gradient of each of the plurality of battery cells, wherein the predetermined time interval includes a resting period after the discharge of each of the plurality of battery cells has ended, and the controller may diagnose a battery cell in an abnormal state by comparing the voltage gradient of each of the plurality of battery cells with a threshold value, wherein the voltage gradient is smaller than the threshold value.

[0009] According to an embodiment, the controller can linearly fit the voltage profile of each of the plurality of battery cells by applying a linear regression method to the voltage profile regarding the voltage of each of the plurality of battery cells.

[0010] According to an embodiment, the controller can calculate the voltage slope by calculating a linear profile, which is a linearly fitted profile of the voltage profile, and calculating an average rate of change, which is the ratio of the voltage change amount to the time change amount in the linear profile.

[0011] According to an embodiment, the controller can calculate the distribution of the voltage gradient associated with the plurality of battery cells and determine the threshold value based on the distribution of the voltage gradient.

[0012] According to an embodiment, the controller can determine a reference value based on the mean of the voltage slope distribution and the standard deviation of the distribution as the threshold value.

[0013] According to an embodiment, the controller can diagnose a battery cell in which the voltage slope is smaller than the threshold value as a cell in which lithium plating has occurred.

[0014] According to an embodiment, the voltage of each of the plurality of battery cells may be an open circuit voltage (OCV).

[0015] A battery management method according to one embodiment disclosed in this document comprises: a step of acquiring the voltage of a plurality of battery cells by an acquisition unit included in a battery management device; a step of calculating the voltage gradient of the plurality of battery cells based on the voltage of the plurality of battery cells acquired in a predetermined time interval by a controller included in the battery management device; and a step of diagnosing the state of each of the plurality of battery cells based on the voltage gradient of each of the plurality of battery cells by the controller, wherein the predetermined time interval includes a resting period after the discharge of each of the plurality of battery cells has ended, and the step of diagnosing the state of each of the plurality of battery cells may include a step of diagnosing a battery cell in an abnormal state by comparing the voltage gradient of each of the plurality of battery cells with a threshold value by the controller, wherein the voltage gradient of each of the plurality of battery cells is smaller than the threshold value.

[0016] According to an embodiment, the controller may include the step of linearly fitting the voltage profiles of each of the plurality of battery cells by applying a linear regression method to the voltage profiles of each of the plurality of battery cells.

[0017] According to an embodiment, the step of calculating the voltage slope may include: a step of calculating a linear profile, which is a linearly fitted profile of the voltage profile, by the controller; and a step of calculating the voltage slope by calculating an average rate of change, which is the ratio of the voltage change amount to the time change amount in the linear profile, by the controller.

[0018] According to an embodiment, the method may further include the step of calculating the distribution of the voltage gradient associated with the plurality of battery cells by the controller; and the step of determining the threshold value based on the distribution of the voltage gradient by the controller.

[0019] According to an embodiment, the step of determining the threshold value based on the distribution of the voltage gradient may include the step of determining the threshold value based on the mean of the distribution of the voltage gradient and the standard deviation of the distribution by the controller.

[0020] According to an embodiment, the step of diagnosing a battery cell in an abnormal state where the voltage slope is smaller than the threshold value may be a step of diagnosing a battery cell where the voltage slope is smaller than the threshold value as a cell in which lithium plating has occurred by the controller.

[0021] According to an embodiment, the voltage of each of the plurality of battery cells may be an open circuit voltage (OCV).

[0022] According to an embodiment, a computer-readable recording medium may be provided that records a program for performing the battery management method. Effects of the invention

[0023] A battery management device and its method of operation according to the embodiments disclosed in this document can diagnose defects or degradation of each of a plurality of battery cells included in a battery cell pack.

[0024] A battery management device and its method of operation according to the embodiments disclosed in this document can diagnose a cell in which lithium plating has occurred among a plurality of battery cells included in a battery cell pack by a non-destructive method.

[0025] In addition, various effects that can be identified directly or indirectly through this document may be provided. Brief explanation of the drawing

[0026] FIG. 1 is a drawing showing a battery cell pack according to one embodiment disclosed in this document. FIG. 2 is a block diagram showing a battery management device according to one embodiment disclosed in this document. FIG. 3 is a diagram showing the voltage profile of a battery cell according to one embodiment disclosed in this document. FIG. 4 is an enlarged view of the voltage profile of a battery cell according to one embodiment disclosed in this document. FIG. 5 is a flowchart of the operation of a battery management device according to one embodiment disclosed in this document. FIG. 6 is an operation flowchart of a battery management device according to one embodiment disclosed in this document. FIG. 7 is a block diagram showing the hardware configuration of a computing system for performing a method of operation of a battery management device according to one embodiment disclosed in this document. Specific details for implementing the invention

[0027] Hereinafter, various embodiments of the present invention are described with reference to the accompanying drawings. However, this is not intended to limit the present invention to specific embodiments and should be understood to include various modifications, equivalents, and / or alternatives of the embodiments of the present invention.

[0028] The various embodiments of this document and the terms used therein are not intended to limit the technical features described in this document to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments. In connection with the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of a noun corresponding to an item may include one or more of said items unless the relevant context clearly indicates otherwise.

[0029] In this document, each of the 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 include any one of the items listed together in the corresponding phrase, or all possible combinations thereof. Terms such as “first,” “second,” “first,” “second,” “A,” “B,” “(a),” or “(b)” may be used simply to distinguish a component from another component and, unless specifically stated otherwise, do not limit the components in any other aspect (e.g., importance or order).

[0030] In this document, where it is mentioned that any (e.g., 1) component is “connected,” “coupled,” or “joined” to another (e.g., 2) component, with or without the terms “functionally” or “communicationly,” or where it is mentioned as “coupled” or “connected,” it means that said component may be connected to said other component directly (e.g., by wire), wirelessly, or through a third component.

[0031] According to one embodiment, the method according to the various embodiments disclosed herein may be provided as included in a computer program product. The computer program product may be traded between a seller and a buyer as a product. The computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or distributed online (e.g., download or upload) through an application store or directly between two user devices. In the case of online distribution, at least a portion of the computer program product may be temporarily stored or temporarily created on a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or a relay server.

[0032] According to various embodiments, each component (e.g., module or program) of the components described above may include a singular or multiple entities, and some of the multiple entities may be separated and placed in other components. According to various embodiments, one or more of the components or operations of the aforementioned components may be omitted, or one or more other components or operations may be added. Generally or additionally, multiple components (e.g., module or program) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the multiple components in the same or similar manner as those performed by the corresponding component among the multiple components prior to integration. According to various embodiments, operations performed by the module, program, or other components 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.

[0033] FIG. 1 is a drawing showing a battery cell pack according to one embodiment disclosed in this document.

[0034] Referring to FIG. 1, a battery cell pack (1000) according to one embodiment disclosed in this document may include a battery cell module (100), a battery management device (200), and a relay (300). According to various embodiments, the battery cell module (100) may be a battery cell, and in this case, the battery cell pack (1000) may have a cell-to-pack structure.

[0035] In FIG. 1, the battery cell module (100) is shown as a single unit, but according to the embodiment, the battery cell module (100) may be composed of multiple units, and the battery cell pack (1000) may have a stacked structure of multiple battery cell modules (100).

[0036] The battery cell module (100) may include a plurality of battery cells (110, 120, 130, 140). Although the plurality of battery cells is shown as four in FIG. 1, it is not limited thereto, and the battery cell module (100) may include n (n is a natural number greater than or equal to 2) battery cells.

[0037] A battery cell module (100) can supply power to a target device (not shown). To this end, the battery cell module (100) may be electrically connected to the target device. Here, the target device may include an electrical, electronic, or mechanical device that operates by receiving power from a battery cell pack (1000) comprising a plurality of battery cells (110, 120, 130, 140). For example, the target device may be an electric vehicle (EV) or an energy storage system (ESS), but is not limited thereto.

[0038] Multiple battery cells (110, 120, 130, 140) are basic units of battery cells capable of charging and discharging electrical energy, and may be lithium-ion (Li-ion) batteries, lithium-ion polymer (Li-ion) batteries, nickel-cadmium (Ni-Cd) batteries, nickel-hydrogen (Ni-MH) batteries, etc., but are not limited thereto. Meanwhile, although FIG. 1 is illustrated as having one battery cell module (100), the battery cell module (100) may be composed of multiple units according to the embodiment.

[0039] The battery management device (200) can manage and / or control the state and / or operation of the battery cell module (100). For example, the battery management device (200) can manage and / or control the state and / or operation of a plurality of battery cells (110, 120, 130, 140) included in the battery cell module (100). The battery management device (200) can manage the charging and / or discharging of the battery cell module (100).

[0040] The battery management device (200) can control the operation of the relay (300). For example, the battery management device (200) can short-circuit the relay (300) to supply power to the target device. Additionally, the battery management device (200) can short-circuit the relay (300) when a charging device is connected to the battery cell pack (1000).

[0041] Additionally, the battery management device (200) can monitor the voltage, current, temperature, etc. of each of the battery cell module (100) and / or the plurality of battery cells (110, 120, 130, 140) included in the battery cell module (100). Furthermore, for monitoring by the battery management device (200), sensors not shown or various measurement modules may be additionally installed at any location such as the battery cell module (100), the charging / discharging path, or the battery cell module (100). Based on the monitored measured values ​​of voltage, current, temperature, etc., the battery management device (200) can calculate parameters indicating the state of the battery cell module (100), such as SOC (State of Charge) or SOH (State of Health).

[0042] According to various embodiments, a defect (e.g., overhang) may occur in a battery cell during the production process of a battery cell module (100) and a plurality of battery cells (110, 120, 130, 140). In a normal battery cell, the negative electrode area is larger than the positive electrode area, but in a defective battery cell with an overhang, the negative electrode area may be smaller than the positive electrode area. Therefore, in a defective battery cell with an overhang, there is no negative electrode portion facing a positive electrode, and the positive electrode may have a protruding shape. Consequently, lithium plating may occur during the use of the defective battery cell.

[0043] Additionally, as the battery cell module (100) and the plurality of battery cells (110, 120, 130, 140) increase in usage period or number of uses, the capacity may decrease, the internal resistance may increase, or lithium plating may occur. Accordingly, the battery management device (200) can diagnose abnormal phenomena inside the battery cell module (100) and the plurality of battery cells (110, 120, 130, 140) based on data of various factors that change according to defects or degradation of the battery cells.

[0044] According to an embodiment, the battery management device (200) can diagnose a battery cell in which lithium plating has occurred by analyzing voltage data of each of the plurality of battery cells (110, 120, 130, 140). Here, lithium plating may refer to a phenomenon in which metallic lithium is deposited at the negative electrode of a battery cell. If lithium plating occurs in a battery cell, the battery cell may ignite during the use of the battery cell.

[0045] Accordingly, the battery management device (200) can diagnose a battery cell with lithium plating without disassembling the battery cell by analyzing the voltage data of each of the plurality of battery cells (110, 120, 130, 140). Through this, the battery management device (200) can quickly and accurately diagnose the defective and abnormal condition of the battery cell in a non-destructive manner and prevent ignition.

[0046] The battery management device (200) may be various electronic devices for managing, diagnosing, or testing the battery. For example, the battery management device (200) may be included in a Battery Management System (BMS) inside or outside the vehicle, or it may be implemented as a separate external device distinct from the BMS inside the vehicle. According to an embodiment, the battery management device (200) may be included in a device for charging and discharging tests, such as a server, a cloud server, or a charge / discharge cycler, or it may be included in various devices for diagnosing or testing the battery.

[0047] FIG. 2 is a block diagram showing a battery management device according to one embodiment disclosed in this document.

[0048] Referring to FIG. 2, the battery management device (200) may include an acquisition unit (210) and a controller (220). However, it is not limited thereto, and some components of the battery management device (200) may be omitted, and other general-purpose components may be further included in the battery management device (200).

[0049] The acquisition unit (210) can acquire status information of each of the plurality of battery cells (110, 120, 130, 140). For example, the acquisition unit (210) can acquire the voltage, current, temperature, etc. of each of the plurality of battery cells (110, 120, 130, 140).

[0050] According to an embodiment, the acquisition unit (210) can acquire the voltage of each of the plurality of battery cells (110, 120, 130, 140). The acquisition unit (210) can acquire the voltage of each of the plurality of battery cells (110, 120, 130, 140) at unit times. According to an embodiment, the acquisition unit (210) can continuously acquire data related to voltage rise and fall during the charging period, the rest period after charging, the discharge period, and / or the rest period after discharge of the plurality of battery cells (110, 120, 130, 140). According to an embodiment, the acquisition unit (210) may include a voltage monitoring circuit or a sensor.

[0051] The controller (220) can control the operations of the battery management device (200). According to an embodiment, the controller (220) can diagnose the state of each of the plurality of battery cells (110, 120, 130, 140) based on the state information of each of the plurality of battery cells (110, 120, 130, 140) acquired from the acquisition unit (210). For example, the controller (220) can calculate a voltage profile based on the state information (e.g., voltage) of each of the plurality of battery cells (110, 120, 130, 140) and analyze the calculated voltage profile to diagnose the state of each of the plurality of battery cells (110, 120, 130, 140).

[0052] According to an embodiment, the controller (220) can calculate a voltage profile for each of the plurality of battery cells (110, 120, 130, 140) for each resting cycle after discharge of the plurality of battery cells (110, 120, 130, 140). Through this, the controller (220) can obtain more voltage profiles for diagnosing the condition of the plurality of battery cells (110, 120, 130, 140) and can increase the accuracy of the diagnosis.

[0053] According to the embodiment, the battery cell (e.g., 110) may be a defective cell (e.g., overhang) due to a problem during the production stage. Alternatively, although there was no problem during the production stage, the battery cell (110) may undergo degradation as it is repeatedly charged and discharged. In the case of such defects or degradation, lithium plating (Li Plating), in which metallic lithium is deposited, may occur at the negative electrode of the battery cell (110). Furthermore, defects and degradation of the battery cell (110) may reduce the performance of the battery cell (110) compared to the initial production state of a normal battery cell. Additionally, continued use of the battery cell (110) in a defective or degraded state may lead to the battery cell (110) igniting. Accordingly, a battery management device (200) including a controller (220) can manage a plurality of battery cells (110, 120, 130, 140) by checking and diagnosing the status of each of the plurality of battery cells (110, 120, 130, 140).

[0054] According to various embodiments, during the idle period after discharge of a battery cell, no current flows through the positive and negative electrodes of the battery cell, allowing lithium ions to move from the positive and negative electrodes to reach an equilibrium state. Due to this movement of lithium ions, the voltage of the battery cell (e.g., Open Circuit Voltage (OCV)) may change during the idle period after discharge. However, if an abnormality such as lithium plating occurs in the battery cell, the time it takes for lithium ions to reach an equilibrium state during the idle period after discharge may be prolonged. Therefore, in a battery cell in an abnormal state, the change in the open circuit voltage during the idle period after discharge may occur more slowly compared to a battery cell in a normal state.

[0055] According to an embodiment, the controller (220) can diagnose a battery cell in an abnormal state based on the voltage during the idle period after the discharge of a plurality of battery cells (110, 120, 130, 140) has ended. For example, the controller (220) can diagnose a battery cell in which lithium plating has occurred by analyzing the slope of the open circuit voltage profile. Through this, the controller (220) can manage the plurality of battery cells (110, 120, 130, 140) based on voltage information obtained without disassembling or destroying the plurality of battery cells (110, 120, 130, 140) and prevent ignition.

[0056] The controller (220) can manage each of the plurality of battery cells (110, 120, 130, 140) by controlling the operation of each of the plurality of battery cells (110, 120, 130, 140). According to an embodiment, the controller (220) can control the charging and / or discharging of each of the plurality of battery cells (110, 120, 130, 140).

[0057] The controller (220) may have a structure for executing instructions that implement the operations of the battery management device (200). The controller (220) may be implemented as an array of multiple logic gates or a general-purpose microprocessor for processing various operations, and may be composed of a single processor or multiple processors. For example, the controller (220) may be implemented in at least one form of a microprocessor, CPU, GPU, and AP.

[0058] The controller (220) may be configured separately from or integrally with memory and / or storage configured to temporarily store data or instructions, and may process various operations by executing instructions stored in the memory and / or storage. The memory and / or storage may store various data, instructions, mobile applications, computer programs, etc. For example, the memory and / or storage may be implemented as a non-volatile device such as ROM, PROM, EPROM, EEPROM, flash memory, PRAM, MRAM, RRAM, FRAM, etc., or as a volatile device such as DRAM, SRAM, SDRAM, PRAM, RRAM, FeRAM, etc., and may be implemented in the form of an HDD, SSD, SD, Micro-SD, etc., or a combination thereof.

[0059] The controller (220) can provide information to the user regarding the degradation state or voltage profile of each of the plurality of battery cells (110, 120, 130, 140). For example, the controller (220) can provide information regarding the degradation state or voltage profile to a user terminal through a communication unit (not shown), and can also provide information regarding the degradation state or voltage profile through a display equipped in a vehicle or charger, etc.

[0060] FIG. 3 is a diagram showing the voltage profile of a battery cell according to one embodiment disclosed in this document.

[0061] Referring to FIG. 3, the controller (220) can acquire time series data of the voltage of each of the plurality of battery cells (110, 120, 130, 140) based on the voltage data of the plurality of battery cells (110, 120, 130, 140) acquired from the acquisition unit (210) at each unit time. According to an embodiment, the voltage data of the plurality of battery cells (110, 120, 130, 140) can be acquired in a predetermined time interval. For example, the voltage data may be the voltage acquired during the charging interval, the resting interval after charging, the discharging interval, and / or the resting interval after discharging of each of the plurality of battery cells (110, 120, 130, 140).

[0062] The controller (220) can calculate a voltage profile (P) representing the voltage change of each of the plurality of battery cells (110, 120, 130, 140) based on the voltage of each of the plurality of battery cells (110, 120, 130, 140) per unit time. Here, the voltage profile (P) of each of the plurality of battery cells (110, 120, 130, 140) may represent a graph representing the open circuit voltage (OCV) of the battery cell over time. For example, the x-axis of the voltage profile may be time (unit: seconds) and the y-axis may be voltage (unit: volts).

[0063] According to an embodiment, the controller (220) can calculate the voltage profile (P) of each of the plurality of battery cells (110, 120, 130, 140) during a rest period after charging and discharging. For example, the controller (220) can calculate the voltage profile (P) of each of the plurality of battery cells (110, 120, 130, 140) during a rest period after the discharge of the plurality of battery cells (110, 120, 130, 140) has ended.

[0064] According to an embodiment, the controller (220) can calculate the voltage profile of each of the plurality of battery cells (110, 120, 130, 140) for each resting cycle after discharge of each of the plurality of battery cells (110, 120, 130, 140).

[0065] Although FIG. 3 only shows the voltage profile (P) of the battery cell (110) during the idle period after discharge has ended, the controller (220) can calculate the voltage profile (P) of each of the other battery cells (120, 130, 140). In addition, for convenience of explanation, the operation of the controller (220) is described below using the battery cell (110) as an example, but is not limited thereto, and the operation of the controller (220) can be applied in the same way to the other battery cells (120, 130, 140).

[0066] FIG. 4 is an enlarged view of the voltage profile of a battery cell according to one embodiment disclosed in this document.

[0067] Referring to FIG. 4, the controller (220) can calculate the slope of the voltage profile (P) of the battery cell (110). According to an embodiment, the controller (220) can calculate the slope of the voltage profile (P) by linearly fitting the voltage profile (P) over a predetermined time interval. Here, the predetermined time interval may include a rest period after the discharge has ended.

[0068] According to the embodiment, the controller (220) may determine a predetermined time interval from immediately after the discharge ends as a predetermined time interval. For example, the controller (220) may determine a resting interval of up to 100 seconds from immediately after the discharge ends as a predetermined time interval. Accordingly, the controller (220) can diagnose whether lithium plating is occurring through the voltage change of a plurality of battery cells (110, 120, 130, 140) during the resting interval after the discharge ends.

[0069] In the resting period after discharge is finished, the slope of the voltage profile (P) of the battery cell (110) may be correlated with the speed at which lithium ions within the battery cell (110) return to an equilibrium state. For example, when the battery cell (110) is in a discharged state, lithium ions can move from the negative electrode to the positive electrode as current is applied to the negative electrode and the positive electrode of the battery cell (110). And when discharge is finished, lithium ions can return to an equilibrium state as no current is applied to the battery cell (110). Here, in order to return to an equilibrium state, lithium ions can move in a direction that eliminates the concentration gradient between the negative electrode and the positive electrode. Thus, the voltage of the battery cell (110) may change during the resting period after discharge. However, if lithium plating occurs in the battery cell (110), the speed at which lithium ions return to an equilibrium state slows down, so the voltage of the battery cell (110) may change slowly.

[0070] Accordingly, the controller (220) can diagnose a battery cell with lithium plating by calculating the slope, which is the amount of change in the voltage profiles of each of the plurality of battery cells (110, 120, 130, 140) during the rest period after discharge has ended. For example, the controller (220) can diagnose the battery cell (110) as a cell with lithium plating if the slope of the voltage profile (P) of the battery cell (110) is smaller than the slope of the voltage profiles of other battery cells (e.g., 120, 130, 140).

[0071] According to an embodiment, the controller (220) can preprocess the voltage profile (P) of each of the plurality of battery cells (110, 120, 130, 140) to calculate the slope of the voltage profile (P). For example, the controller (220) can linearly fit the voltage profile (P) of each of the plurality of battery cells (110, 120, 130, 140). Here, linear fitting may mean approximating data that is not linearly distributed linearly.

[0072] According to the embodiment, the controller (220) can linearly fit the voltage profile (P) to a straight line. Through this, the controller (220) can accurately calculate the slope of the voltage profile (P) in a distributed data format or the voltage profile (P) in a curved form. In addition, the controller (220) can diagnose the state of each of the plurality of battery cells (110, 120, 130, 140) by comparing the slopes calculated from the voltage profiles (P) of each of the plurality of battery cells (110, 120, 130, 140).

[0073] According to an embodiment, the controller (220) can linearly fit the voltage profile (P) using any data fitting analysis method. For example, the controller (220) can linearly fit the voltage profile (P) using any regression analysis method. Here, the regression analysis method may include at least one of linear regression, polynomial regression, logarithmic regression, and exponential regression. According to an embodiment, the controller (220) can linearly fit the voltage profile (P) using the Linear Regression method of Python Scikit-Learn.

[0074] According to an embodiment, the controller (220) can calculate a linear profile (L) based on a voltage profile (P). Here, the linear profile (L) may refer to a profile to which the voltage profile (P) is linearly fitted.

[0075] According to an embodiment, the controller (220) can calculate the slope of the voltage profile (P) based on the linear profile (L). For example, the controller (220) can calculate the slope of the voltage profile (P) based on the average rate of change of the linear profile (L) over a predetermined time interval. In another aspect, the controller (220) can calculate the slope of the voltage profile (P) as the ratio of the voltage change amount of the linear profile (L) to the time change amount over a predetermined time interval.

[0076] According to an embodiment, the controller (220) can diagnose each of the plurality of battery cells (110, 120, 130, 140) based on the slope of the voltage profile (P) of each of the plurality of battery cells (110, 120, 130, 140). According to an embodiment, the controller (220) can compare the slope of the voltage profile (P) of each of the plurality of battery cells (110, 120, 130, 140) with a threshold value and diagnose a battery cell with a slope smaller than the threshold value as being in an abnormal state. Here, the threshold value may refer to a value that serves as a criterion for diagnosing a battery cell as being in an abnormal state.

[0077] As previously explained, the slope of the voltage profile (P) may be correlated with the rate at which lithium ions return to equilibrium. Therefore, if lithium plating occurs in a specific battery cell (e.g., 110), the rate at which lithium ions return to equilibrium slows down, so the voltage of the battery cell (110) may change slowly. Accordingly, the controller (220) can diagnose a battery cell in which the slope of the voltage profile (P) is smaller than a threshold value as being in a state where lithium plating has occurred (i.e., an abnormal state).

[0078] According to an embodiment, the controller (220) can determine a threshold value based on the distribution of the slope of the voltage profile (P) of each of the plurality of battery cells (110, 120, 130, 140). For example, the controller (220) can calculate the distribution of slopes associated with the plurality of battery cells (110, 120, 130, 140). Here, the distribution of slopes may refer to a probability distribution having the slope of each of the plurality of battery cells (110, 120, 130, 140) included in the battery cell pack (1000) as a random variable.

[0079] Accordingly, the controller (220) can calculate a probability distribution having the slope of the voltage profile (P) of a plurality of battery cells (110, 120, 130, 140) as a random variable. According to an embodiment, the controller (220) can determine a threshold value based on the distribution of the slope of the voltage profile (P). For example, the controller (220) can calculate the mean and standard deviation of the distribution based on the distribution of the slope. Thus, the controller (220) can determine a reference value based on the mean and standard deviation of the distribution as the threshold value. Through this, the controller (220) can identify a battery cell among the plurality of battery cells (110, 120, 130, 140) included in the battery cell pack (1000) in which the slope of the voltage profile (P) is an outlier.

[0080] According to an embodiment, when the distribution of the slopes of the voltage profiles (P) of a plurality of battery cells (110, 120, 130, 140) is a normal distribution, the controller (220) can determine any confidence interval as a threshold value. For example, the controller (220) can determine a confidence interval of 95% or less (e.g., 96%, 96.5%, 97%, 97.5%, … 99.5%, etc.) as a threshold value.

[0081] According to the embodiment, the controller (220) can diagnose a battery cell in which the slope of the voltage profile (P) is smaller than the threshold value as a cell in which lithium plating has occurred. According to the embodiment, the wider the confidence interval determined by the controller (220), that is, the smaller the threshold value determined, the better the controller (220) can diagnose an abnormal battery cell. Through this, the controller (220) can diagnose a battery cell having a significantly smaller slope of the voltage profile (P) compared to other battery cells among a plurality of battery cells (110, 120, 130, 140) as an abnormal battery cell.

[0082] According to an embodiment, the controller (220) can determine a threshold value based on the following <Equation 1>.

[0083] <Mathematical Formula 1>

[0085] x=m-(2.1*σ)

[0086] In <Mathematical Formula 1>, x may represent a threshold value, m may represent the average of the slope distribution of the voltage profile (P) of the plurality of battery cells (110, 120, 130, 140) included in the battery cell pack (1000), and σ may represent the standard deviation of the slope distribution of the voltage profile (P) of the plurality of battery cells (110, 120, 130, 140) included in the battery cell pack (1000).

[0087] FIG. 5 is a flowchart of the operation of a battery management device according to one embodiment disclosed in this document.

[0088] Referring to FIG. 5, the operation of the battery management device (200) may include the step of calculating a voltage profile regarding the voltage of each of the plurality of battery cells (S101), the step of calculating the slope of the voltage profile by linearly fitting the voltage profile over a predetermined time interval (S102), and the step of diagnosing the state of each of the plurality of battery cells based on the slope of the voltage profile of each of the plurality of battery cells (S103).

[0089] In step S101, the controller (220) of the battery management device (200) can calculate a voltage profile (P) regarding the voltage of each of the plurality of battery cells (110, 120, 130, 140) (S101). According to an embodiment, the controller (220) can calculate a voltage profile (P) of the open circuit voltage (OCV) of each of the plurality of battery cells (110, 120, 130, 140) during a rest period after discharge.

[0090] In step S102, the controller (220) can calculate the slope of the voltage profile (P) by linearly fitting the voltage profile (P) over a predetermined time interval (S102). According to an embodiment, the controller (220) can determine the rest period immediately after the discharge of each of the plurality of battery cells (110, 120, 130, 140) is finished as a predetermined time interval.

[0091] In step S103, the controller (220) can diagnose the state of each of the plurality of battery cells (110, 120, 130, 140) based on the slope of the voltage profile (P) of each of the plurality of battery cells (110, 120, 130, 140) (S103). According to an embodiment, the controller (220) can diagnose a battery cell in which the slope of the voltage profile (P) is smaller than a threshold value as a cell in which lithium plating has occurred.

[0092] FIG. 6 is an operation flowchart of a battery management device according to one embodiment disclosed in this document.

[0093] Referring to FIG. 6, the operation of the battery management device (200) may include the step of calculating a distribution of slopes related to a plurality of battery cells (S201), the step of determining a threshold value based on the mean of the distribution of slopes and the standard deviation of the distribution (S202), and the step of diagnosing a battery cell in which the slope is smaller than the threshold value as a cell in which lithium plating has occurred (S203).

[0094] In step S201, the controller (220) of the battery management device (200) can calculate the distribution of slopes associated with a plurality of battery cells (110, 120, 130, 140) (S201). Here, the distribution of slopes may refer to a probability distribution having the slope of the voltage profile (P) of each of the plurality of battery cells (110, 120, 130, 140) included in the battery cell pack (1000) as a probability variable.

[0095] In step S202, the controller (220) can determine a threshold value based on the mean of the slope distribution and the standard deviation of the distribution (S202).

[0096] In step S202, the controller (220) can diagnose a battery cell in which the slope is smaller than the threshold as a cell in which lithium plating has occurred (S203).

[0097] FIG. 7 is a block diagram showing the hardware configuration of a computing system for performing a method of operation of a battery management device according to one embodiment disclosed in this document.

[0098] Referring to FIG. 7, a computing system (2000) according to one embodiment disclosed in this document may include an MCU (2010), a memory (2020), an input / output I / F (2030), and a communication I / F (2040).

[0099] The MCU (2010) may be a processor that executes various programs stored in memory (2020) (e.g., battery cell data collection program, profile calculation program, data analysis program, distribution calculation program, battery cell diagnosis program, etc.), processes various information including battery cell data, data regression analysis data, probability distribution data, etc. through these programs, and performs the functions of the controller (220) included in the battery management device (200) shown in FIGS. 1 to 6 above.

[0100] The memory (2020) can store various programs such as a battery cell data collection program, a profile calculation program, a data analysis program, a distribution calculation program, and a battery cell diagnosis program. In addition, the memory (2020) can store various information including battery cell data, data regression analysis data, and probability distribution data.

[0101] These memories (2020) may be provided in multiple quantities as needed. The memories (2020) may be volatile memories or non-volatile memories. As volatile memories, the memory (2020) may use RAM, DRAM, SRAM, etc. As non-volatile memories, the memory (2020) may use ROM, PROM, EAROM, EPROM, EEPROM, flash memory, etc. The examples of the memories (2020) listed above are merely examples and are not limited to these examples.

[0102] The input / output I / F (2030) can provide an interface that enables data transmission and reception between an input device (not shown), such as a keyboard, mouse, or touch panel, an output device (not shown), and an MCU (2010).

[0103] The communication I / F (2040) is configured to transmit and receive various data with a server and may be various devices capable of supporting wired or wireless communication. For example, the battery management device (200) can transmit and receive various information, including the SOC, OCV, parameters, etc. of the battery cell, from a separately provided external server through the communication I / F (2040).

[0104] In this way, a computer program according to one embodiment disclosed in this document may be implemented as a module that performs, for example, the functions illustrated in FIG. 2, by being written to memory (2020) and processed by an MCU (2010).

[0105] In the foregoing, although all components constituting the embodiments disclosed in this document have been described as being combined or operating in combination, the embodiments disclosed in this document are not necessarily limited to such embodiments. That is, within the scope of the purposes of the embodiments disclosed in this document, all components may be selectively combined in one or more ways to operate.

[0106] Furthermore, terms such as "include," "compose," or "have" as described above, unless specifically stated otherwise, mean that the relevant component may be inherent; thus, they should be interpreted as allowing for the inclusion of additional components rather than excluding them. All terms, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the embodiments disclosed in this document pertain, unless otherwise defined. Commonly used terms, such as those defined in advance, should be interpreted in accordance with their meaning in the context of the relevant technology and, unless explicitly defined in this document, should not be interpreted in an ideal or overly formal sense.

[0107] The foregoing disclosure outlines the features of several embodiments to enable those skilled in the art to better understand aspects of the present disclosure. Those skilled in the art will understand that the present disclosure can be readily used as a basis for designing or modifying other structures to perform the same purpose or achieve the same advantages as the embodiments introduced herein. Furthermore, those skilled in the art will recognize that such equivalent configurations do not depart from the scope of the present disclosure and that various changes, substitutions, and modifications may be made in the present disclosure without departing from the scope of the present disclosure. Explanation of the symbols

[0108] 100: Battery cell module 110, 120, 130, 140: Battery cells 200: Battery Management Unit 210: Acquisition Section 220: Controller 300: Relay 1000: Battery cell pack 2000: Computing Systems 2010: MCU 2020: Memory 2030: Input / Output I / F 2040: Communication I / F P: Voltage profile L: Linear profile

Claims

Claim 1 A battery management device comprising: a acquiring unit for acquiring the voltage of a plurality of battery cells; and a controller for calculating the voltage gradient of the plurality of battery cells based on the voltage of the plurality of battery cells acquired in a predetermined time interval, and diagnosing the state of each of the plurality of battery cells based on the voltage gradient of each of the plurality of battery cells, wherein the predetermined time interval includes a resting period after the discharge of each of the plurality of battery cells has ended, and the controller compares the voltage gradient of each of the plurality of battery cells with a threshold value and diagnoses a battery cell in an abnormal state if the voltage gradient is smaller than the threshold value. Claim 2 A battery management device according to claim 1, wherein the controller applies a linear regression method to a voltage profile regarding the voltage of each of the plurality of battery cells to linearly fit the voltage profile of each of the plurality of battery cells. Claim 3 A battery management device according to claim 2, wherein the controller calculates a linear profile in which the voltage profile is a linearly fitted profile, and calculates the voltage slope by calculating an average rate of change, which is the ratio of the voltage change amount to the time change amount in the linear profile. Claim 4 A battery management device according to claim 1, wherein the controller calculates the distribution of the voltage gradient associated with the plurality of battery cells and determines the threshold value based on the distribution of the voltage gradient. Claim 5 In claim 4, the controller is a battery management device that determines a reference value based on the average of the distribution of the voltage slope and the standard deviation of the distribution as the threshold value. Claim 6 In claim 1, the controller is a battery management device that diagnoses a battery cell in which the voltage slope is smaller than the threshold value as a cell in which lithium plating has occurred. Claim 7 A battery management device according to claim 1, wherein the voltage of each of the plurality of battery cells is an open circuit voltage (OCV). Claim 8 A battery management method comprising: a step of acquiring the voltage of a plurality of battery cells by means of an acquisition unit included in a battery management device; a step of calculating the voltage slope of the plurality of battery cells based on the voltage of the plurality of battery cells acquired in a predetermined time interval by means of a controller included in the battery management device; and a step of diagnosing the state of each of the plurality of battery cells based on the voltage slope of each of the plurality of battery cells by means of the controller, wherein the predetermined time interval includes a resting period after the discharge of each of the plurality of battery cells has ended, and the step of diagnosing the state of each of the plurality of battery cells includes, by means of the controller, a step of diagnosing a battery cell in an abnormal state by comparing the voltage slope of each of the plurality of battery cells with a threshold value. Claim 9 A battery management method according to claim 8, comprising the step of linearly fitting the voltage profile of each of the plurality of battery cells by applying a linear regression method to the voltage profile of each of the plurality of battery cells by the controller. Claim 10 A battery management method according to claim 9, wherein the step of calculating the voltage slope comprises: a step of calculating a linear profile, wherein the voltage profile is a linearly fitted profile, by the controller; and a step of calculating the voltage slope by calculating an average rate of change, which is the ratio of the voltage change amount to the time change amount in the linear profile, by the controller. Claim 11 A battery management method according to claim 8, further comprising: a step of calculating the distribution of the voltage gradient associated with the plurality of battery cells by the controller; and a step of determining the threshold value based on the distribution of the voltage gradient by the controller. Claim 12 A battery management method according to claim 11, wherein the step of determining the threshold value based on the distribution of the voltage gradient comprises the step of determining the threshold value based on the mean of the distribution of the voltage gradient and the standard deviation of the distribution by the controller. Claim 13 A battery management method according to claim 8, wherein the step of diagnosing a battery cell in an abnormal state where the voltage slope is smaller than the threshold value is, by the controller, the step of diagnosing the battery cell where the voltage slope is smaller than the threshold value as a cell in which lithium plating has occurred. Claim 14 A battery management method according to claim 8, wherein the voltage of each of the plurality of battery cells is an open circuit voltage (OCV). Claim 15 A computer-readable recording medium having a program that performs a battery management method according to any one of paragraphs 8 through 14.

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