Battery management device and method

Abstract

A battery management device according to one embodiment of the present invention includes a profile processing unit configured to acquire a charge / discharge profile of a cell group in which a plurality of cells are electrically connected; a characteristic point selection unit configured to select characteristic points corresponding to inflection points from the charge / discharge profile; and a diagnostic unit configured to diagnose degradation imbalance of the cell group using characteristic information including the number of characteristic points.

Description

Technical Field

[0001] This application claims priority based on Korean Patent Application No. 10-2023-0126117 filed on September 21, 2023, and all the contents disclosed in the specification and drawings of that application are incorporated herein by reference.

[0002] The present invention relates to a technology for diagnosing and managing the state of a battery, and more specifically, to a battery management apparatus and method for effectively diagnosing the deterioration imbalance of a cell group.

Background Art

[0003] With the rapid growth in the demand for portable electronic products such as notebook computers, video cameras, and mobile phones that use electricity as a power source, and the general commercialization of mobile robots, electric bicycles, electric carts, and electric vehicles, research on high-performance secondary batteries that can be repeatedly charged and discharged has been actively conducted.

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary batteries, etc. Among them, lithium secondary batteries have almost no memory effect compared to nickel-based secondary batteries, so they can be freely charged and discharged, have the advantage of a very low self-discharge rate, and also have the characteristics of high energy density and high operating voltage. Therefore, they are being studied more intensively than other types of secondary batteries and are being more widely applied to actual products.

[0005] In recent years, secondary batteries are widely used not only in small devices such as portable electronic devices but also in medium and large-sized devices such as electric vehicles and energy storage systems (ESS).

[0006] In this case, battery modules, in which multiple electrically connected rechargeable batteries are housed together inside a module case, are primarily used. When higher power or capacity is required, battery packs, in which multiple battery modules are electrically connected, may also be used.

[0007] In secondary battery cells, cell assemblies, battery modules, or battery packs (hereinafter collectively referred to as "batteries"), power efficiency and safety are important factors. Therefore, research is actively being conducted on battery management systems (BMS) that monitor the electrical characteristics of batteries and perform feedback control such as charging and discharging using the monitoring results.

[0008] Unlike energy-generating systems that use fossil fuels, secondary battery systems generate energy through electrochemical reactions. As a result of continuous charge-discharge cycles, they cannot maintain their initial performance, i.e., their BOL (Beginning of Life) state, and gradually deteriorate or become obsolete.

[0009] As batteries continue to be used (charged and discharged), their utility decreases due to capacity degradation, output degradation, and other factors, and their safety also becomes a risk factor. Therefore, accurate predictions of the current battery degradation and its remaining lifespan are necessary for controlling usage to be limited, determining replacement timing, setting objective prices for battery sharing or rental, and improving the efficiency of battery reuse or recycling.

[0010] On the other hand, the multiple battery cells that make up a battery may exhibit differences in electrical characteristic values ​​or variations in the degree of aging or deterioration of their intrinsic drive performance (hereinafter referred to as "deterioration imbalance") due to differences in individual dynamic states resulting from intrinsic characteristics such as internal resistance, human error due to the operating environment, cooling efficiency, and capacity.

[0011] Thus, degradation imbalance can occur not only when the degree of degradation differs due to the use of each cell, but also due to defects in the manufacturing process.

[0012] If the degradation levels of multiple cells grouped together through electrical connections differ, the overall driving performance of the grouped cell group deteriorates. Therefore, a technology is needed to accurately diagnose degradation imbalances in cell groups where multiple cells are electrically connected, so that subsequent processes and operations such as limited use, elimination of charging and discharging, and determination of replacement timing can be carried out more effectively.

[0013] However, most conventional methods or techniques for diagnosing degradation are methods that predict the degree of degradation or remaining lifespan for each individual cell, making it difficult to effectively diagnose degradation imbalances or uneven degradation across an entire cell group, which is essentially a group of multiple cells.

[0014] Furthermore, even if the degradation imbalance of cell groups is diagnosed using conventional methods, the process requires functional processing such as statistically comparing the degradation levels of each individual cell after all the calculations have been completed. This results in very low computational efficiency and reduced accuracy of the information. [Overview of the Initiative] [Problems that the invention aims to solve]

[0015] The present invention was devised to solve the above-mentioned problems, and aims to provide a battery management device and method that can quickly and accurately diagnose the degree of degradation imbalance in a cell group through a process of grasping characteristic information of the charge-discharge profile or its differential profile for the entire cell group.

[0016] The technical problems that this invention aims to solve are not limited to those described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described later. [Means for solving the problem]

[0017] A battery management device according to one aspect of the present invention includes a profile processing unit configured to acquire a charge-discharge profile of a cell group in which a plurality of cells are electrically connected; a characteristic point selection unit configured to select characteristic points corresponding to inflection points from the charge-discharge profile; and a diagnostic unit configured to diagnose degradation imbalance of the cell group using characteristic information including the number of characteristic points.

[0018] If there is only one characteristic point, the diagnostic unit may be configured to diagnose that the degradation imbalance has not occurred in the cell group.

[0019] If there are multiple characteristic points, the diagnostic unit may be configured to diagnose that the degradation imbalance has occurred in the cell group.

[0020] The charge / discharge profile may be a profile that shows the correspondence between the voltage and capacity of the cell group.

[0021] The characteristic point selection unit may include a function processing unit configured to generate a differential profile, which is a profile showing the correspondence between the capacity and differential voltage of the cell group or the correspondence between the voltage and differential capacitance of the cell group, based on the charge-discharge profile, and a point selection unit configured to select the characteristic points from the differential profile.

[0022] The point selection unit may be configured to, when a differential profile showing the correspondence between the capacitance and the differential voltage is generated, determine the capacitance with the smallest corresponding differential voltage in the generated differential profile, and select the characteristic point from among multiple peaks included in a capacitance range larger than the determined capacitance.

[0023] When a differential profile indicating the correspondence between the voltage and the differential capacitance is generated, the point selection unit determines the voltage at which the corresponding differential capacitance is the largest in the generated differential profile, and selects the characteristic point from among a plurality of peaks included in a voltage range greater than the determined voltage.

[0024] The point selection unit may be configured to select, as the characteristic point, a peak among the peaks where the SOC (State of Charge) of the cell group is in the range of 40% or more and 70% or less.

[0025] Furthermore, when it is diagnosed that the deterioration imbalance has occurred in the cell group, the battery management device may further include a management control unit configured to change the usage conditions of the cell group so that the charge and discharge of the cell group are restricted.

[0026] When there are a plurality of the characteristic points, the characteristic information may further include separation degree information between the characteristic points.

[0027] The diagnosis unit may be configured to generate diagnosis data including deepening degree information that increases as the separation degree information increases, as information about the degree of the deterioration imbalance.

[0028] Furthermore, when it is diagnosed that the deterioration imbalance has occurred in the cell group, the battery management device may further include a management control unit configured to change the usage conditions of the cell group so that the restriction of the charge and discharge range of the cell group varies according to the magnitude of the separation degree information.

[0029] A battery pack according to another aspect of the present invention includes a battery management device according to an aspect of the present invention.

[0030] An automobile according to still another aspect of the present invention includes a battery management device according to an aspect of the present invention.

[0031] A battery management method according to yet another aspect of the present invention includes a profiling step of obtaining a charge-discharge profile of a cell group in which a plurality of cells are electrically connected; a characteristic point selection step of selecting characteristic points corresponding to inflection points from the charge-discharge profile; and a diagnostic step of diagnosing degradation imbalance of the cell group using characteristic information of the characteristic points. [Effects of the Invention]

[0032] According to one aspect of the present invention, degradation imbalances can be accurately diagnosed not from a microscopic perspective of individual cells, but from the perspective of cell groups actually applied to application devices such as banks, modules, and battery packs, thereby improving the effectiveness of battery control and management.

[0033] According to one aspect of the present invention, the degree of degradation imbalance in a cell group can be easily and accurately diagnosed through software processing targeting the charge-discharge profile or differential profile thereof of the cell group.

[0034] From this perspective, since the diagnostic method according to one aspect of the present invention can be implemented through software that can be installed on a BMS or the like, or a module that executes it, it can offer even greater expandability and applicability.

[0035] Furthermore, according to one aspect of the present invention, information on the degree of degradation imbalance can be effectively combined with a process that applies different usage restriction ranges to the cell group, thereby further improving the efficiency of battery management processing.

[0036] The effects of the present invention are not limited to those described above, and other effects of the present invention not mentioned herein will be clearly understood by those skilled in the art from the claims.

[0037] The drawings accompanying this specification, along with the detailed description of the invention described later, serve to further facilitate understanding of the technical concept of the present invention, and the present invention is not to be construed as being limited only to what is shown in the drawings. [Brief explanation of the drawing]

[0038] [Figure 1] This is a block diagram showing the detailed configuration of a battery management device according to one embodiment of the present invention. [Figure 2] Figure 1 is a block diagram showing the detailed configuration of the characteristic point sorting unit. [Figure 3] This is a flowchart illustrating the processing steps according to one embodiment of the present invention. [Figure 4] This is a flowchart illustrating the processing steps according to another embodiment of the present invention. [Figure 5] This is a flowchart illustrating the processing steps according to yet another embodiment of the present invention. [Figure 6] This figure shows the differential profile of the reference cell group. [Figure 7] This figure shows the differential profile of the target cell group. [Figure 8] This diagram illustrates the characteristic points of the differential profile. [Figure 9] This diagram illustrates the degree of separation between multiple characteristic points (peaks). [Figure 10] This diagram illustrates the degree of separation between multiple characteristic points (peaks). [Figure 11] This figure schematically shows an automobile according to another embodiment of the present invention. [Figure 12] This figure schematically illustrates a battery management method according to yet another embodiment of the present invention. [Modes for carrying out the invention]

[0039] The terms and words used in this specification and in the claims are not to be interpreted in a manner limited to their general and dictionary meanings, but rather in a manner corresponding to the technical idea of ​​the present invention, in accordance with the principle that inventors can appropriately define the concepts of terms in order to best describe their invention.

[0040] Therefore, the embodiments described herein and the configurations shown in the drawings represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the invention. It should be understood that there are various equivalents and modifications that can substitute for them at the time of filing this application.

[0041] Furthermore, in describing the present invention, if it is determined that a specific description of a related known configuration or function would obscure the gist of the present invention, such detailed description will be omitted.

[0042] Terms that include ordinal numbers, such as "1st," "2nd," etc., are used to distinguish one of several components from others, and these terms do not limit the components themselves.

[0043] When a part of the specification "includes" a certain component, unless otherwise specified, this does not exclude other components, but rather means that it may include other components.

[0044] Furthermore, when a part of the specification is described as being "connected" to another part, this includes not only "direct connections" but also "indirect connections" mediated by other elements.

[0045] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0046] Figure 1 is a block diagram showing the detailed configuration of a battery management device 100 according to one embodiment of the present invention, Figure 2 is a block diagram showing the detailed configuration of the characteristic point sorting unit shown in Figure 1, and Figure 3 is a flowchart illustrating the processing process according to one embodiment of the present invention.

[0047] First, the detailed configuration of the battery management device 100 according to one embodiment of the present invention and the processes performed by these configurations will be described in detail with reference to Figure 1 and related drawings, and the detailed contents of the characteristic point sorting unit 130 will be described later.

[0048] Referring to Figure 1, the battery management device 100 includes a measurement unit 110, a profile processing unit 120, a characteristic point selection unit 130, a diagnostic unit 140, a management control unit 150, and a reference data storage unit 160.

[0049] Specifically, the characteristic point sorting unit 130 may include an information storage unit 131, a function processing unit 133, and a point sorting unit 135, depending on the embodiment, as shown in Figure 2.

[0050] Prior to a detailed description of the present invention, it is obvious that the battery management device 100 according to one embodiment of the present invention can be realized through the application of various combinations of electronic elements and components such as storage means, arithmetic processing means, and input / output means. Therefore, each component of the battery management device 100 shown in Figure 1 is understood to be a functionally or logically distinguishable component, rather than a physically distinguishable component. The same applies to each component of the characteristic point sorting unit 130 shown in Figure 2.

[0051] In other words, each component shown in the diagram corresponds to a logical configuration for effectively explaining the technical idea of ​​the present invention. Therefore, even if the components are integrated or separated, as long as the function performed by the logical configuration of the present invention is realized, it is interpreted as being within the scope of the present invention. Furthermore, it goes without saying that components that perform the same or similar functions are interpreted as being within the scope of the present invention, regardless of whether their names match.

[0052] Furthermore, since the battery management method according to one embodiment of the present invention can be implemented as a collection of processes or algorithms related to data processing, handling, control, calculation, input / output, etc., it can be implemented not only by combinations of logical configurations shown in Figure 1, etc., but also in the form of software installed and driven in a system, device, computer (or equivalent device), BMS, module, or its subordinate configuration.

[0053] A battery management device 100 according to one embodiment of the present invention is configured to diagnose whether degradation imbalance has occurred and / or the degree of degradation imbalance (hereinafter referred to as "degree of deterioration") for a cell group 50 in which a plurality of cells 51 are electrically connected, and may be configured to generate and output diagnostic data for the cell group 50 for organic linkage with other configurations, modules / devices, etc., depending on the embodiment.

[0054] As shown in Figure 1, it goes without saying that multiple cell groups 50 (50-1, 50-2, 50-3, ..., 50-N) can be provided in the target battery 10, which is the higher-level assembly, and are diagnosed and managed by the battery management device 100 according to one embodiment of the present invention.

[0055] Furthermore, although Figure 1 shows a configuration in which multiple cells 51 constituting the cell group 50 are connected in parallel, this is just one example, and depending on the embodiment, each cell 51 may be in a configuration in which multiple unit cells are connected in series.

[0056] The profile processing unit 120 of the present invention is configured to acquire the charge-discharge profile of a cell group 50 in which multiple cells are electrically connected. Here, the charge-discharge profile refers to a profile that shows the correspondence between the voltage and capacity of the cell group 50. On the other hand, capacity may be replaced with SOC (State of Charge). That is, depending on the embodiment, the charge-discharge profile may be a profile that shows the correspondence between voltage and SOC.

[0057] The charge / discharge profile can be stored and utilized in the profile processing unit 120 of the present invention by receiving input from a separately provided device or module.

[0058] Depending on the embodiment, the measurement unit 110 may measure the voltage, current, etc., of the cell group 50 during the charging or discharging process to generate electrical characteristic values ​​of the cell group 50 (S300, see Figure 3). The profile processing unit 120 may then generate a charge / discharge profile based on the generated electrical characteristic values ​​(S310). Depending on the embodiment, the charge / discharge profile may be a dataset in which voltage values ​​and capacity values ​​measured at the same time are mapped.

[0059] State of Charge (SOC) is a parameter that expresses the current capacity as a percentage of the maximum capacity, ranging from 0 to 1 or 0% to 100%. Various techniques and technologies such as ampere counting, equivalent circuit models (ECM), and Kalman filters can be applied, and depending on the embodiment, the system may be configured to further reflect temperature information when generating SOC information.

[0060] Once the charge / discharge profile is generated in this manner (S310), the characteristic point selection unit 130 selects characteristic points corresponding to inflection points from the charge / discharge profile (S320).

[0061] An inflection point can be a point where the trend of the slope changes relative to the general shape of the charge-discharge profile graph or curve. In other words, an inflection point is a point where the sign of the rate of increase in slope changes (from positive to negative or from negative to positive), and it is a point where a change in the general shape of the charge-discharge profile graph occurs, i.e., a change in the general shape between convex (convex upwards) and concave (convex downwards).

[0062] An inflection point is a point where a change occurs due to the intrinsic characteristics of cell 51 or cell group 50, which is a collection of multiple cells, and can function as an important parameter point that can define the intrinsic state or characteristics of cell 51, etc.

[0063] Identifying or selecting such inflection points can be done using tools or algorithms that parse (analyze) the general shape of the graph. Differential profiles of charge-discharge profiles may also be used to more clearly and accurately identify inflection points through numerical interpretation. Further details on this will be discussed later.

[0064] Once characteristic points corresponding to inflection points in the charge / discharge profile are selected in this manner, the diagnostic unit 140 is configured to diagnose the degradation imbalance of the cell group 50 using the characteristic information of the characteristic points.

[0065] Specifically, characteristic information may include information about the number of characteristic points.

[0066] For example, if there is one characteristic point (single number), the diagnostic unit 140 may be configured to diagnose that no degradation imbalance has occurred in the cell group. Conversely, if there are multiple characteristic points, the diagnostic unit 140 may diagnose that degradation imbalance has occurred in the cell group (S330).

[0067] For example, in the case of a cell group 50 consisting only of cells in a BOL state (excluding cases where defective cells are mixed in during the manufacturing process, etc.) (hereinafter referred to as the "reference cell group"), since the electrochemical behavioral characteristics of the individual cells constituting the reference cell group are substantially identical, there may be only one characteristic point selected from the charge-discharge profile of the reference cell group. This is because the states of the multiple cells included in the reference cell group are substantially identical.

[0068] Furthermore, even when the degree of degradation due to the use (charging and discharging) of multiple cells 51 belonging to cell group 50 is substantially the same, the number of characteristic points selected from the charge-discharge profile of the cell group 50 may be only one. This is because the degradation of the multiple cells 51 included in cell group 50 is uniform.

[0069] On the other hand, if degradation imbalance occurs among multiple cells 51 belonging to cell group 50, there may be multiple characteristic points selected from the charge-discharge profile of cell group 50. This is because the characteristics of multiple cells 51 that have degraded unbalanced are comprehensively reflected in the charge-discharge profile of cell group 50.

[0070] A battery management device 100 according to one embodiment of the present invention can easily and accurately diagnose degradation imbalances in cell groups 50 by using characteristic changes in the general shape of such charge-discharge profiles, that is, the differentiation or separation (split) phenomenon of characteristic points (inflection points) observed from the charge-discharge profile.

[0071] Depending on the embodiment, the diagnostic unit 140 may be configured to generate diagnostic data containing the diagnostic results (S340) for organic linkage with subsequent control processes or other components as described above.

[0072] Figure 2 is a block diagram showing the detailed configuration of the characteristic point sorting unit 130 shown in Figure 1, and Figure 4 is a flowchart illustrating the processing process according to another embodiment of the present invention.

[0073] As described above, the characteristic point selection unit 130 can select characteristic points corresponding to inflection points from the charge / discharge profile.

[0074] Specifically, the characteristic point sorting unit 130 may include an information storage unit 131, a function processing unit 133, and a point sorting unit 135, as shown in Figure 2. As mentioned above, the components shown in Figure 2 correspond to the logical configuration.

[0075] The information storage unit 131 can store information such as the charge / discharge profile of the cell group 50, identification information, specifications of the cells 51 included, expiration date, and usage history (S400).

[0076] The function processing unit 133 can generate a differential profile by performing function processing on the charge / discharge profiles of the cell group 50 stored in the information storage unit 131 (S410).

[0077] For example, the function processing unit 133 may generate a differential profile showing the correspondence between the capacitance and differential voltage of the cell group 50. As another example, the function processing unit 133 may generate a differential profile showing the correspondence between the voltage and differential capacitance of the cell group 50.

[0078] Here, the differential voltage is the derivative of voltage with respect to capacitance, expressed as "dV / dQ", and its unit may be [V / Ah]. If the charge-discharge profile that forms the basis of the differential profile is the profile generated during the charging process, then by setting the X-axis of the 2D coordinate system to SOC (or capacitance) and the Y-axis to the differential voltage, the differential profile (differential voltage profile) can be represented as shown in the graph in Figure 6, etc.

[0079] Furthermore, differential capacitance is the derivative of capacitance with respect to voltage, and is expressed as "dQ / dV," with units of [Ah / V]. Differential profiles (differential capacitance profiles) can be represented as two-dimensional graphs by methods such as setting the X-axis of a two-dimensional coordinate system to voltage and the Y-axis to differential capacitance.

[0080] In the following explanation, we will assume that the differential profile is the differential voltage profile generated during the charging process of the cell group 50, as shown in Figure 6 and other figures. However, the technical concept of the present invention can be applied not only when a differential profile is generated based on the charge-discharge profile generated during the discharge process by applying simple transformations such as symmetry shifts and variable conversions, but also when a differential profile (differential capacitance profile) showing the correspondence between the voltage and differential capacitance of the cell group 50 is used.

[0081] As described above, once a differential profile is generated, the point selection unit 135 can select the peaks of the differential profile as characteristic points (S420).

[0082] As described above, characteristic points are the points corresponding to the inflection points in the charge-discharge profile of cell group 50. Specifically, the peak of the differential profile is the point where the sign of the slope changes in the differential profile, and where the slope is zero. For example, the point corresponding to the local maximum of the differential profile is the peak of the differential profile. In other words, since characteristic points (inflection points) appear as the vertices (peaks) of an upwardly convex shape in the differential profile, characteristic points can be selected more accurately and clearly by selecting peaks that have the corresponding shape characteristics.

[0083] For example, if a differential profile showing the correspondence between capacitance and differential voltage is generated, the point selection unit 135 can determine the capacitance with the smallest corresponding differential voltage in the generated differential profile. The point selection unit 135 can then be configured to select a characteristic point from among multiple peaks that fall within a capacitance range larger than the determined capacitance.

[0084] As another example, if a differential profile showing the correspondence between voltage and differential capacitance is generated, the point selection unit 135 may determine the voltage at which the corresponding differential capacitance is largest in the generated differential profile. The point selection unit 135 may then be configured to select a characteristic point from among multiple peaks that fall within a voltage range greater than the determined voltage.

[0085] The specific technical details of the present invention, which involves selecting characteristic points using peaks and diagnosing degradation imbalance, will be described below with further reference to Figures 6 to 10.

[0086] Figure 6 shows the differential profile of a reference cell group. As mentioned above, the reference cell group represents a group of cells consisting of cells in a BOL state, so the differential profile shown in Figure 6 can be used as a criterion for judging degradation imbalances, etc.

[0087] As shown in Figure 6, there can be multiple points in the differential profile of the reference cell group that correspond to peaks in terms of shape.

[0088] In the case of a secondary battery substrate cell 51 or a cell group 50 which is an assembly thereof, the intrinsic characteristic changes of the negative electrode are concentrated in the intermediate region of the SOC, so a peak (Peak1) corresponding to a local maximum may be included in the intermediate region of the SOC of the differential profile. For example, in the embodiment shown in Figure 6, a peak (Peak1) may be included in the SOC range of 40% to 70% of the differential profile.

[0089] As can be seen in Figure 6, in the case of the reference cell group, i.e., the cell group 50 where degradation imbalance does not occur, there is only one characteristic point in the charge / discharge profile. On the other hand, as can be seen in Figures 7 and 8, in the case of the cell group 50 with degradation imbalance where the degree of degradation of individual cells 51 differs, a phenomenon of peak separation or differentiation (split) occurs, and multiple characteristic points (Peak2) may be detected.

[0090] For example, in the embodiment shown in Figure 7, the point selection unit 135 can determine the lowest differential voltage from the differential profile. For example, the lowest differential voltage is found around 30% of the State of Cycle (SOC). The point selection unit 135 can detect characteristic points (Peak 2) in the SOC interval after the SOC corresponding to the lowest differential voltage. For example, the point selection unit 135 can detect characteristic points (Peak 2) in the range of 40% to 70% of the SOC.

[0091] When multiple characteristic points are detected or selected in this manner (S430, Figure 4), the diagnostic unit 140 of the present invention can diagnose that a degradation imbalance has occurred in the cell group 50 (S450).

[0092] In contrast, if one characteristic point is detected in the cell group 50, the degree of deterioration or aging of the cells 51 belonging to the cell group 50 can be considered to be at the same level within the error range, and therefore the diagnostic unit 140 of the present invention can diagnose that no deterioration imbalance has occurred in the cell group 50 (S440). Depending on the embodiment, even if multiple characteristic points are detected within a range that does not exceed the reference error, the system may be configured to consider that only one characteristic point has been detected.

[0093] Specifically, changes in the intrinsic characteristics of the negative electrode can be concentrated in the target SOC interval, which is included in a predetermined SOC range from the SOC corresponding to the lowest differential voltage in the differential profile. In other words, if unbalanced degradation occurs in multiple cells 51, differences may occur in the negative electrode state of the multiple cells 51. Therefore, the diagnostic unit 140 can diagnose whether degradation imbalance has occurred in the cell group 50 based on the number of characteristic points in the target SOC interval.

[0094] As the cell 51 is used repeatedly, its driving performance deteriorates and the likelihood of anomalous behavioral characteristics occurring increases. Therefore, it is preferable that the reference error be configured to be variable, and that it be set so that it becomes smaller as the usage period of the cell group 50 lengthens, that is, so that the judgment of degradation imbalance becomes stricter.

[0095] The diagnostic unit 140 may be configured to generate and output diagnostic data representing the diagnosis of the degradation imbalance in the cell group 50, as described above (S460).

[0096] The control unit 150 may be configured to change the operating conditions of the cell group 50 so that charging and discharging of the cell group 50 is restricted if a degradation imbalance occurs in the cell group 50 based on the diagnostic data input from the diagnostic unit 140 (S470).

[0097] For example, the control unit 150 may change the upper and / or lower SOC limits of a cell group 50 in order to prevent a cell group 50 that has experienced degradation imbalance from degrading further. Specifically, the control unit 150 may decrease the upper SOC limit or increase the lower SOC limit. Alternatively, the control unit 150 may decrease the upper SOC limit while simultaneously increasing the lower SOC limit.

[0098] Depending on the embodiment, it is preferable that the diagnostic unit 140 or the management control unit 150 of the present invention is configured to output information (identification information, degradation depth information, etc.) about the cell group 50 in which degradation imbalance has occurred to a user terminal or the vehicle's information system.

[0099] Further embodiments of the present invention will be described in detail below with reference to Figure 5 and other figures.

[0100] As described above, the characteristic information may include information on the number of characteristic points, but in order to realize a more preferred embodiment, if multiple characteristic points are detected (S500), the characteristic information may further include information on the degree of separation between the characteristic points.

[0101] Specifically, the diagnostic unit 140 of the present invention can calculate separation information of multiple characteristic points when data related to characteristic points is input from the characteristic point selection unit 130 (S510). Furthermore, the diagnostic unit 140 can be configured to generate information about the degree of degradation imbalance, such that the greater the separation information, the greater the degree of deepening (S520).

[0102] Separation information can be generated by calculating the distance (SOC criterion) (D1, D2) between multiple characteristic points, or by processing this statistically (variance, weighted average, etc.).

[0103] Using the example in Figure 9 as a reference, in Case 1, D1 (Figure 9(a)) is the reference for separation information, and in Case 2, D2 (Figure 9(b)) is the reference. For reference, Case 1 and Case 2 represent the respective differential profiles of degradation imbalance cell groups 50 having different degradation characteristics.

[0104] Depending on the embodiment, separation information may be generated using the distance between the characteristic points of the reference cell group and the respective characteristic points of the degraded unbalanced cell group 50, as shown in Figure 10. In Figure 10(a), "d11+d12" is the basis for the separation information, and in Figure 10(b), "d21+d22" is the basis.

[0105] The charge / discharge profile, differential profile, characteristic point information, etc., of the reference cell group can be stored and utilized in a reference data storage unit 160 or the like, which is communicatively connected to the diagnostic unit 140 of the present invention.

[0106] When the diagnostic unit 140 generates diagnostic data including degradation level information and outputs it to the management control unit 150 (S530), the management control unit 150 controls the charging and discharging of the corresponding cell group 50 to be limited depending on whether degradation imbalance has occurred.

[0107] Furthermore, the control unit 150 can control the limit on the charge / discharge range of a cell group 50 to differ depending on the magnitude of the deepening information, such as by relatively increasing the limit on the charge / discharge range in the case of a cell group 50 with relatively large deepening information (S540).

[0108] For example, in the embodiment shown in Figure 10, since the depth of process information for Case 2 is greater than that for Case 1, the control unit 150 can further restrict the charge / discharge range of the cell group in Case 2 compared to the charge / discharge range of the cell group in Case 1. For example, the control unit 150 can reduce the upper limit SOC of the cell group in Case 1 by 10% and increase the lower limit SOC by 10%. Then, the control unit 150 can reduce the upper limit SOC of the cell group in Case 2 by 15% and increase the lower limit SOC by 15%.

[0109] In other words, the battery management device 100 can diagnose each of the multiple cell groups 50 constituting the target battery 10, not only whether degradation imbalance has occurred, but also the degree to which the degradation imbalance has deepened, using precisely quantified numerical values. This allows for more precise execution of tasks such as determining the replacement timing for a specific cell group 50, setting usage restrictions, and controlling charging and discharging.

[0110] On the other hand, the battery management device 100 according to one embodiment of the present invention can be applied to a battery management system (BMS). That is, the BMS according to the present invention may include the battery management device 100 described above. In such a configuration, at least some of the components of the battery management device 100 can be realized by complementing or adding to the functions of the components included in a conventional BMS.

[0111] Furthermore, a battery management device 100 according to one embodiment of the present invention may be provided in a battery pack. That is, the battery pack according to the present invention may include the above-described battery management device 100 and one or more cell groups 50.

[0112] Figure 11 is a schematic diagram showing an automobile 1100 according to another embodiment of the present invention.

[0113] Referring to Figure 11, a battery pack according to one embodiment of the present invention can be installed in a vehicle 1100 such as an electric vehicle (EV) or a hybrid vehicle (HV). The battery pack 1110 can drive the vehicle 1100 by supplying power to a motor through an inverter provided in the vehicle 1100. Here, the battery pack 1110 may include a battery management device 100. That is, the vehicle 1100 may include a battery management device 100. In this case, the battery management device 100 may be an onboard diagnostic device included in the vehicle 1100.

[0114] Figure 12 is a schematic diagram illustrating a battery management method according to yet another embodiment of the present invention.

[0115] Referring to Figure 12, the battery management method may include a profile processing step S110, a characteristic point selection step S120, and a diagnostic step S130.

[0116] Preferably, each step of the battery management method can be performed by the battery management device 100. The following sections will either omit or briefly explain any content that overlaps with what has been described above.

[0117] The profiling step S110 is a step of obtaining a charge / discharge profile of a cell group in which multiple cells are electrically connected, and can be performed by the profiling unit 120.

[0118] The characteristic point selection step S120 is a step of selecting characteristic points corresponding to inflection points from the charge / discharge profile, and can be performed by the characteristic point selection unit 130.

[0119] For example, the characteristic point selection unit 130 can identify inflection points in the charge / discharge profile and select characteristic points corresponding to the identified inflection points. As another example, the characteristic point selection unit 130 can identify peaks in the differential profile and select characteristic points corresponding to the identified peaks.

[0120] Preferably, the characteristic point selection unit 130 can select characteristic points in the intermediate SOC region (for example, the region between 40% and 70% of the SOC) of the overall SOC interval of the cell group 50.

[0121] The diagnostic step S130 is a step of diagnosing degradation imbalance in a cell group using characteristic information of characteristic points, and can be performed by the diagnostic unit 140.

[0122] For example, if there is only one characteristic point, the diagnostic unit 140 may diagnose that no degradation imbalance has occurred in the cell group 50. As another example, if there are multiple characteristic points, the diagnostic unit 140 may diagnose that degradation imbalance has occurred in the cell group 50.

[0123] The embodiments of the present invention described above are not limited to apparatus and methods, but can also be implemented through a program that realizes the functions corresponding to the configuration of the embodiments of the present invention, or through a recording medium on which such a program is recorded. Such a program or recording medium can be easily implemented by those skilled in the art based on the description of the embodiments described above.

[0124] As described above, the present invention has been explained with limited embodiments and drawings, but it goes without saying that the present invention is not limited thereto, and that various modifications and variations are possible within the equivalent scope of the technical idea and claims of the present invention by persons with ordinary skill in the art to which the present invention pertains.

[0125] Furthermore, the present invention described above can be substituted, modified, and altered in various ways by a person with ordinary skill in the art to which the present invention pertains, without departing from the technical spirit of the invention, and is not limited by the embodiments described above and the accompanying drawings. For diverse modifications, all or part of each embodiment can be selectively combined to form the present invention. [Explanation of Symbols]

[0126] 10: Target Battery 50: Cell Group 51: Cell 100: Battery management device 110: Measuring part 120: Profile Processing Unit 130: Characteristic Point Sorting Unit 131: Information storage section 133: Function Processing Unit 135: Point sorting department 140: Diagnostic Department 150: Management and Control Unit 160: Reference data storage unit 1100: Automobile 1110: Battery Pack

Claims

1. A profile processing unit configured to acquire the charge / discharge profile of a cell group in which multiple cells are electrically connected, A characteristic point selection unit configured to select characteristic points corresponding to inflection points from the charge / discharge profile, A battery management device comprising: a diagnostic unit configured to diagnose degradation imbalance of the cell group using characteristic information including the number of characteristic points; and

2. The aforementioned diagnostic unit, If there is only one characteristic point, it is diagnosed that the degradation imbalance has not occurred in the cell group. The battery management device according to claim 1, configured to diagnose that the degradation imbalance has occurred in the cell group if there are multiple such characteristic points.

3. The charge / discharge profile is a profile that shows the correspondence between the voltage and capacity of the cell group. The characteristic point selection unit is, A function processing unit is configured to generate a differential profile, which is a profile showing the correspondence between the capacity and differential voltage of the cell group or the correspondence between the voltage and differential capacitance of the cell group, based on the charge-discharge profile. The battery management device according to claim 1, further comprising: a point selection unit configured to select characteristic points from the differential profile.

4. The aforementioned point sorting unit is, The battery management device according to claim 3, wherein, when a differential profile showing the correspondence between the capacity and the differential voltage is generated, the device is configured to determine the capacity with the smallest corresponding differential voltage in the generated differential profile and to select the characteristic point from among a plurality of peaks included in a capacity range larger than the determined capacity.

5. The aforementioned point sorting unit is, The battery management device according to claim 3, wherein, when a differential profile showing the correspondence between the voltage and the differential capacitance is generated, the device is configured to determine the voltage at which the corresponding differential capacitance is largest in the generated differential profile, and to select the characteristic point from among a plurality of peaks included in a voltage range greater than the determined voltage.

6. The battery management device according to claim 4 or 5, wherein the point selection unit is configured to select peaks among the peaks in which the SOC of the cell group is in the range of 40% to 70% as characteristic points.

7. The battery management device according to claim 1, further comprising a management control unit configured to change the operating conditions of the cell group so as to limit the charging and discharging of the cell group when it is diagnosed that the degradation imbalance has occurred in the cell group.

8. If there are multiple characteristic points, the characteristic information further includes information on the degree of separation between the characteristic points. The battery management device according to claim 1, wherein the diagnostic unit is configured to generate diagnostic data that includes, as information about the degree of degradation imbalance, depth information which increases as the separation information increases.

9. The battery management device according to claim 8, further comprising a management control unit configured to change the usage conditions of the cell group such that, when it is diagnosed that the degradation imbalance has occurred in the cell group, the limitations on the charge and discharge range of the cell group differ according to the magnitude of the separation information.

10. A battery pack including a battery management device according to any one of claims 1 to 5 or 7 to 9.

11. An automobile comprising a battery management device according to any one of claims 1 to 5 or 7 to 9.

12. A profiling step to obtain the charge / discharge profile of a cell group in which multiple cells are electrically connected, A characteristic point selection step in which characteristic points corresponding to inflection points are selected from the charge / discharge profile, A battery management method comprising a diagnostic step of diagnosing degradation imbalance in the cell group using characteristic information of the characteristic points.

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