Battery management device and method

Abstract

A battery management device according to one embodiment of the present invention includes: a voltage acquisition unit configured to acquire the open-circuit voltage of a battery; a profile acquisition unit configured to acquire a differential profile showing the correspondence between the differential capacity and voltage of the battery; and a control unit configured to determine the voltage pattern of the battery based on the open-circuit voltage and a pre-stored voltage history, determine a plurality of peaks from the differential profile if the determined voltage pattern is a predetermined pattern, determine a negative electrode peak and a positive electrode peak from the determined plurality of peaks, and diagnose the state of the battery by comparing the rate of change of the negative electrode peak with respect to a pre-set reference negative electrode peak and the rate of change of the positive electrode peak with respect to a pre-set reference positive electrode peak.

Description

Technical Field

[0001] This application claims priority based on Korean Patent Application No. 10-2023-0109374 filed on August 21, 2023, and all of the content disclosed in the specification and drawings of the said application is incorporated into this application.

[0002] The present invention relates to a battery management device and method, and more particularly, to a battery management device and method for diagnosing the state of a battery and adjusting the usage conditions of the battery according to the diagnosis result.

Background Art

[0003] In recent years, as the demand for portable electronic products such as notebook computers, video cameras, and mobile phones has rapidly increased and the development of electric vehicles, energy storage batteries, robots, artificial satellites, etc. has become full-scale, research on high-performance batteries that can be repeatedly charged and discharged has been actively conducted.

[0004] Currently, commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium batteries, etc. Among them, lithium batteries are attracting attention because they can be freely charged and discharged because they hardly have a memory effect compared to nickel-based batteries, have a very low self-discharge rate, and have a high energy density. Although various studies have been conducted on such batteries from the viewpoints of increasing capacity and density, improving lifespan and safety is also important. In order to improve the safety of a battery, a technology for accurately diagnosing the current state of the battery is required.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention was devised to solve the above problems, and an object thereof is to provide a battery management device and method capable of tracking and diagnosing the state of a battery to increase the lifespan of the battery.

[0006] Other objects and advantages of the present invention can be understood from the following description and more clearly from the embodiments of the present invention. Furthermore, the objects and advantages of the present invention can be realized by the means and combinations thereof shown in the claims. [Means for solving the problem]

[0007] A battery management device according to one aspect of the present invention includes a profile acquisition unit configured to acquire a differential profile showing the correspondence between the differential capacity and voltage of a battery; a voltage acquisition unit configured to acquire the open-circuit voltage of the battery; and a control unit configured to determine the voltage pattern of the battery based on the open-circuit voltage and a pre-stored voltage history, determine a plurality of peaks from the differential profile if the determined voltage pattern is a predetermined pattern, determine a negative electrode peak and a positive electrode peak from the determined plurality of peaks, and diagnose the state of the battery by comparing the rate of change of the negative electrode peak with respect to a pre-set reference negative electrode peak and the rate of change of the positive electrode peak with respect to a pre-set reference positive electrode peak.

[0008] The control unit may be configured to calculate the rate of change of the differential capacity of the negative electrode peak, calculate the rate of change of the differential capacity of the positive electrode peak, compare the rate of change of the differential capacity of the negative electrode peak with the rate of change of the differential capacity of the positive electrode peak, and diagnose the state of the battery according to the result of the comparison.

[0009] The control unit may be configured to calculate the rate of change of the differential capacitance of the negative electrode peak by calculating the ratio of the differential capacitance of the negative electrode peak to a preset reference differential capacitance of the negative electrode, and to calculate the rate of change of the differential capacitance of the positive electrode peak by calculating the ratio of the differential capacitance of the positive electrode peak to a preset reference differential capacitance of the positive electrode.

[0010] The control unit may be configured to diagnose the state of the battery as a positive and negative electrode degradation state if the rate of change of the differential capacity of the negative electrode peak exceeds the rate of change of the differential capacity of the positive electrode peak.

[0011] The control unit may be configured to diagnose the state of the battery as a positive electrode degradation state if the rate of change of the differential capacity of the negative electrode peak is less than or equal to the rate of change of the differential capacity of the positive electrode peak.

[0012] The control unit may be configured to adjust the pre-set operating conditions for the battery based on the diagnosed state of the battery.

[0013] The control unit may be configured to calculate the voltage change rate based on the open-circuit voltage and a pre-stored voltage history, and to compare the calculated voltage change rate with a pre-set reference change rate to determine whether the battery's voltage pattern is a decreasing pattern or a non-decreasing pattern.

[0014] The control unit may be configured to determine a plurality of peaks from the differential profile if the determined voltage pattern is a decreasing pattern.

[0015] The voltage acquisition unit may be configured to acquire the open-circuit voltage after the battery has finished charging.

[0016] The profile acquisition unit may be configured to acquire a differential profile that shows the correspondence between the differential capacity and voltage of the battery during the charging process.

[0017] A battery pack according to another aspect of the present invention includes a battery management device according to one aspect of the present invention.

[0018] An automobile according to yet another aspect of the present invention includes a battery management device according to one aspect of the present invention.

[0019] A battery management method according to yet another aspect of the present invention includes: a voltage pattern determination step of determining the voltage pattern of the battery based on the open-circuit voltage of the battery and a voltage history stored in advance; a peak determination step of determining a plurality of peaks from a differential profile showing the correspondence between the differential capacity and voltage of the battery, if the determined voltage pattern is a predetermined pattern; an electrode peak determination step of determining a negative electrode peak and a positive electrode peak from among the determined plurality of peaks; and a state diagnosis step of diagnosing the state of the battery by comparing the rate of change of the negative electrode peak with respect to a preset reference negative electrode peak and the rate of change of the positive electrode peak with respect to a preset reference positive electrode peak. [Effects of the Invention]

[0020] According to one aspect of the present invention, it is possible to specifically diagnose the degree of battery degradation and the cause of battery degradation. In particular, since it is possible to diagnose combined degradation in which both the positive and negative electrodes are degraded as the cause of battery degradation, a more accurate diagnosis of the current state of the battery is possible.

[0021] Furthermore, according to one aspect of the present invention, the battery usage conditions are appropriately adjusted according to the state of the battery, thereby increasing the battery life.

[0022] 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.

[0023] The drawings accompanying this specification, along with the detailed description of the invention described below, are intended 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]

[0024] [Figure 1] This diagram schematically shows a battery management device according to one embodiment of the present invention. [Figure 2] A diagram schematically showing a differential profile according to an embodiment of the present invention. [Figure 3] A diagram schematically showing a reference profile according to an embodiment of the present invention. [Figure 4] A diagram showing the differential capacitance of a plurality of peaks included in a reference profile and a differential profile according to an embodiment of the present invention. [Figure 5] A diagram showing an exemplary configuration of a battery pack according to another embodiment of the present invention. [Figure 6] A diagram schematically showing an automobile according to still another embodiment of the present invention. [Figure 7] A diagram schematically showing a battery management method according to still another embodiment of the present invention.

MODE FOR CARRYING OUT THE INVENTION

[0025] In this specification and the claims, the terms and words used are not to be construed as being limited to the general and dictionary meanings, but rather are to be construed in accordance with the principle that the inventor can appropriately define the concept of the terms in order to explain the invention in the best way, and are to be construed in meanings and concepts corresponding to the technical idea of the present invention.

[0026] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and thus there can be various equivalents and modifications that can replace them at the time of this application.

[0027] Also, in the description of the present invention, when it is determined that a specific description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

[0028] Terms including ordinal numbers such as first, second, etc. are used to distinguish one of various components from other components, and the components are not limited by these terms.

[0029] 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.

[0030] 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.

[0031] Here, "battery" refers to a single, independent cell that has a negative terminal and a positive terminal and is physically separable. For example, a lithium-ion battery or a lithium-polymer battery can be considered a battery. Alternatively, "battery" may refer to a battery bank, battery module, or battery pack in which multiple cells are connected in series and / or parallel. For the sake of explanation, in the following, "battery" will be described as referring to a single, independent cell.

[0032] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0033] Figure 1 is a schematic diagram showing a battery management device 100 according to one embodiment of the present invention.

[0034] Referring to Figure 1, a battery management device 100 according to one embodiment of the present invention includes a profile acquisition unit 110, a voltage acquisition unit 120, and a control unit 130.

[0035] The profile acquisition unit 110 may be configured to acquire a differential profile DP that shows the correspondence between the differential capacity and voltage of the battery.

[0036] Here, differential capacitance represents the instantaneous rate of change of capacitance with respect to voltage. That is, differential capacitance is the value obtained by differentiating capacitance with respect to voltage, and can be expressed as "dQ / dV".

[0037] A battery profile is a profile that shows the correspondence between voltage (V) and capacity (Q) when a battery's State of Charge (SOC) is charged from 0% to 100%. Furthermore, differentiating the battery profile with respect to voltage can generate a differential profile DP that shows the correspondence between differential capacity (dQ / dV) and voltage (V). Conversely, the battery profile may also show the correspondence between voltage (V) and capacity (Q) when a battery's SOC is discharged from 100% to 0%.

[0038] For example, the C rate is not particularly limited when charging or discharging to generate a battery profile. However, it is preferable to charge or discharge the battery at a low rate in order to obtain a more accurate battery profile and differential profile DP. For example, a battery profile can be generated during the process of charging or discharging the battery at 0.05C.

[0039] Preferably, the profile acquisition unit 110 may be configured to acquire a differential profile DP that shows the correspondence between the differential capacity and voltage of the battery during the charging process. For example, a battery profile may be acquired during the charging process of the battery, and the differential profile DP may be acquired from the battery profile.

[0040] For example, the profile acquisition unit 110 can directly receive the differential profile DP of the battery from an external source. That is, the profile acquisition unit 110 can acquire the differential profile DP of the battery by receiving the differential profile DP via a wired and / or wireless connection to an external source.

[0041] As another example, the profile acquisition unit 110 may receive battery information regarding the battery's voltage and capacity. The profile acquisition unit 110 may then generate a battery profile based on the received battery information and generate a differential profile DP based on the generated battery profile. In other words, the profile acquisition unit 110 may acquire the differential profile DP by directly generating the differential profile DP based on the battery information.

[0042] As yet another example, the profile acquisition unit 110 can directly measure the battery voltage and current. For example, the profile acquisition unit 110 can be directly connected to the positive and negative terminals of the battery to directly measure the battery voltage. The profile acquisition unit 110 can also measure the charge and discharge current of the battery and calculate the battery capacity based on the measured current. Furthermore, the profile acquisition unit 110 can generate a differential profile DP based on the battery voltage and capacity. That is, the profile acquisition unit 110 can acquire a differential profile DP based on the directly measured battery voltage and current.

[0043] The profile acquisition unit 110 may be connected to the control unit 130 in a communicative manner. For example, the profile acquisition unit 110 may be connected to the control unit 130 by wire and / or wirelessly. The profile acquisition unit 110 may transmit the acquired differential profile DP to the control unit 130.

[0044] Figure 2 is a schematic diagram showing a differential profile DP according to one embodiment of the present invention.

[0045] In the embodiment shown in Figure 2, the differential profile DP can be represented as a two-dimensional graph where the X-axis is set to voltage (V) and the Y-axis is set to differential capacitance (dQ / dV).

[0046] The voltage acquisition unit 120 may be configured to acquire the open-circuit voltage (OCV) of the battery.

[0047] Here, open-circuit voltage refers to the battery voltage measured when the battery is in a dormant state.

[0048] Specifically, the voltage acquisition unit 120 may be configured to acquire the open-circuit voltage after the battery has finished charging. For example, when the battery voltage reaches the charging completion voltage (e.g., 4.2V), the battery charging is completed. After a certain period of time has elapsed since the battery has finished charging, the battery may stabilize with a voltage lower than the charging completion voltage. The voltage acquisition unit 120 may acquire the open-circuit voltage of the stabilized battery.

[0049] For example, the voltage acquisition unit 120 can directly receive the open-circuit voltage of the battery from an external source. That is, the voltage acquisition unit 120 can acquire the open-circuit voltage of the battery by being connected to an external source via wired and / or wireless connection to receive the open-circuit voltage.

[0050] As another example, the voltage acquisition unit 120 may be directly connected to the positive and negative terminals of the battery. The voltage acquisition unit 120 can then acquire the open-circuit voltage by directly measuring the open-circuit voltage of the stabilized battery. In some cases, the voltage acquisition unit 120 may be implemented as part of a configuration in which the battery voltage is measured by the profile acquisition unit 110.

[0051] The voltage acquisition unit 120 may be connected to the control unit 130 in a communicative manner. For example, the voltage acquisition unit 120 may be connected to the control unit 130 by wire and / or wirelessly. The voltage acquisition unit 120 may transmit the acquired open-circuit voltage to the control unit 130.

[0052] The control unit 130 may be configured to determine the battery voltage pattern based on the open-circuit voltage and a previously stored voltage history.

[0053] Here, the voltage history can be information that maps open-circuit voltages to the time of measurement. That is, the voltage history can be historical information for open-circuit voltages measured at previous points in time. For example, if a battery has been charged n times, the n open-circuit voltages measured after the completion of charging can be stored as the voltage history.

[0054] The control unit 130 can compare the measured open-circuit voltage with one or more open-circuit voltages included in the voltage history. Specifically, the control unit 130 can determine the pattern of change in the open-circuit voltage over time.

[0055] For example, if the open-circuit voltage decreases over time, the control unit 130 may determine the voltage pattern to be a decreasing pattern. As another example, if the open-circuit voltage increases over time, or if the open-circuit voltage remains constant even as time passes, the control unit 130 may determine the voltage pattern to be a non-decreasing pattern. That is, non-decreasing patterns may include voltage increasing patterns and voltage maintaining patterns.

[0056] The control unit 130 may be configured to determine multiple peaks from the differential profile DP if the determined voltage pattern is a predetermined pattern.

[0057] Here, the voltage pattern determined by the control unit 130 is either a decreasing pattern or a non-decreasing pattern. The control unit 130 may be configured to determine multiple peaks from the differential profile DP if the determined voltage pattern is a decreasing pattern. In other words, the control unit 130 does not determine multiple peaks from the differential profile DP if the determined voltage pattern is a non-decreasing pattern.

[0058] Specifically, the control unit 130 can determine a peak in the differential profile DP where the slope (instantaneous rate of change) is 0 and the general shape is convex upwards. That is, the slope on the low-voltage side is positive and the slope on the high-voltage side is negative around the peak. In other words, the control unit 130 can be configured to determine the maximum point of the differential profile DP as the peak.

[0059] For example, in the embodiment shown in Figure 2, the control unit 130 can determine the first peak p1, the second peak p2, the third peak p3, the fourth peak p4, and the fifth peak p5 from the differential profile DP.

[0060] The control unit 130 may be configured to determine the negative electrode peak and the positive electrode peak from among the multiple peaks that have been determined.

[0061] Here, the negative electrode peak best represents the state of the negative electrode, and the positive electrode peak best represents the state of the positive electrode. Generally, the negative electrode peak appears in the low voltage range (for example, the voltage range corresponding to the section with a SOC of 50% or less), and the positive electrode peak appears in the high voltage range (for example, the voltage range corresponding to the section with a SOC of 50% or more).

[0062] The negative electrode peak can be determined depending on the type of negative electrode in the battery. For example, if the battery contains a single negative electrode active material, the negative electrode voltage range in which the negative electrode peak appears can be preset depending on the type of negative electrode active material. As another example, if the battery contains multiple negative electrode active materials, the negative electrode voltage range in which the negative electrode peak appears can be preset depending on the types of multiple negative electrode active materials and the ratio of the multiple negative electrode active materials. The control unit 130 can determine the negative electrode peak from among the multiple peaks included in the differential profile DP based on the negative electrode voltage range preset to correspond to the type of negative electrode in the battery.

[0063] For example, in the embodiment shown in Figure 2, the battery is a graphite-based battery containing graphite as the negative electrode active material. The control unit 130 can determine the first peak p1 as the negative electrode peak from among the first peak p1, second peak p2, third peak p3, fourth peak p4, and fifth peak p5, based on a negative electrode voltage band preset for the graphite-based battery.

[0064] The positive electrode peak can be determined according to the type of positive electrode of the battery. The voltage range in which the positive electrode peak appears can be preset based on the types of positive electrode active materials and the ratios of these positive electrode active materials. For example, the positive electrode voltage range in which the positive electrode peak appears may be set differently for a battery with an NCM (Ni:Co:Mn) ratio of 8:1:1 and a battery with an NCM ratio of 6:2:2. The control unit 130 can determine the positive electrode peak from among the multiple peaks included in the differential profile DP based on the positive electrode voltage range preset to correspond to the type of positive electrode of the battery. For example, in the embodiment of Figure 2, the battery is a high-nickel battery with an NCM ratio of 8:1:1. Based on the positive electrode voltage range preset for the high-nickel battery, the control unit 130 can determine the fifth peak p5 as the positive electrode peak from among the first peak p1, second peak p2, third peak p3, fourth peak p4, and fifth peak p5.

[0065] The control unit 130 may be configured to diagnose the battery status by comparing the rate of change of the negative electrode peak with respect to a preset reference negative electrode peak and the rate of change of the positive electrode peak with respect to a preset reference positive electrode peak.

[0066] Figure 3 is a schematic diagram of a reference profile RP according to one embodiment of the present invention. Specifically, the reference profile RP in Figure 3 is a differential profile for a battery in the BOL (Beginning of Life) state. The reference profile RP may include a first peak p1, a second peak p2, a third peak p3, a fourth peak p4, and a fifth peak p5. Here, the first peak p1 may be pre-set as the reference negative electrode peak, and the fifth peak p5 may be pre-set as the reference positive electrode peak. The differential capacitance of the reference negative electrode peak may be pre-set as the reference negative electrode differential capacitance. Similarly, the differential capacitance of the reference positive electrode peak may be pre-set as the reference positive electrode differential capacitance.

[0067] Specifically, the control unit 130 can calculate the rate of change of the differential capacitance of the negative electrode peak based on the differential capacitance of the negative electrode peak. For example, the control unit 130 can calculate the rate of change of the differential capacitance of the negative electrode peak by calculating the ratio of the differential capacitance of the negative electrode peak to a preset reference negative electrode differential capacitance. For example, the control unit 130 can calculate the rate of change of the differential capacitance of the negative electrode peak by calculating the formula "differential capacitance of negative electrode peak ÷ reference negative electrode differential capacitance × 100". Here, 100 in the formula is a constant used to express the rate of change of differential capacitance in the range of 0% to 100%, and can therefore be omitted. When such a constant is omitted, the rate of change of differential capacitance may have a value in the range of 0 to 1.

[0068] Similarly, the control unit 130 can calculate the rate of change of the differential capacitance of the positive electrode peak based on the differential capacitance of the positive electrode peak. For example, the control unit 130 can calculate the rate of change of the differential capacitance of the positive electrode peak by calculating the ratio of the differential capacitance of the positive electrode peak to a preset reference positive electrode differential capacitance. For example, the control unit 130 can calculate the rate of change of the differential capacitance of the positive electrode peak by calculating the formula "differential capacitance of positive electrode peak ÷ reference positive electrode differential capacitance × 100". In this formula as well, constants can be omitted.

[0069] Figure 4 shows the differential capacities of multiple peaks included in the reference profile RP and differential profile DP according to one embodiment of the present invention.

[0070] In the embodiment shown in Figure 4, the reference negative electrode differential capacitance is d1, and the reference positive electrode differential capacitance is d5. The differential capacitance of the negative electrode peak included in the differential profile DP is d1n, and the differential capacitance of the positive electrode peak is d5n. The control unit 130 can calculate the rate of change of the differential capacitance of the negative electrode peak by calculating the formula "d1n ÷ d1 × 100". The control unit 130 can also calculate the rate of change of the differential capacitance of the positive electrode peak by calculating the formula "d5n ÷ d5 × 100".

[0071] Furthermore, the control unit 130 may be configured to compare the rate of change of the differential capacitance at the negative electrode peak with the rate of change of the differential capacitance at the positive electrode peak. Specifically, the control unit 130 can compare the magnitude of the rate of change of the differential capacitance at the negative electrode peak with the magnitude of the rate of change of the differential capacitance at the positive electrode peak. For example, the control unit 130 can compare the magnitudes of the rate of change of the differential capacitance at the negative electrode peak with the rate of change of the differential capacitance at the positive electrode peak.

[0072] The control unit 130 may be configured to diagnose the battery status according to the comparison results.

[0073] For example, the control unit 130 may be configured to diagnose the battery state as positive and negative electrode degradation if the rate of change of the differential capacity of the negative electrode peak exceeds the rate of change of the differential capacity of the positive electrode peak. Conversely, the control unit 130 may be configured to diagnose the battery state as positive electrode degradation if the rate of change of the differential capacity of the negative electrode peak is less than or equal to the rate of change of the differential capacity of the positive electrode peak.

[0074] Specifically, if the positive electrode of the battery is degraded, the voltage pattern of the open-circuit voltage after the battery is fully charged may show a decreasing pattern. Furthermore, if the negative electrode of the battery is degraded, the rate of change of the differential capacity at the peak of the negative electrode may exceed the rate of change of the differential capacity at the peak of the positive electrode. In other words, the battery management device 100 can diagnose the extent of combined degradation of the positive and negative electrodes by considering both the voltage pattern of the open-circuit voltage and the rate of change of the differential capacity at the peaks of the positive and negative electrodes. Therefore, the battery management device 100 can diagnose not only the extent of battery degradation but also the specific cause of the battery degradation. In particular, since it can diagnose combined degradation where both the positive and negative electrodes are degraded as the cause of battery degradation, the battery management device 100 can diagnose the current state of the battery more accurately.

[0075] On the other hand, the control unit 130 provided in the battery management device 100 may selectively include a processor, ASIC (Application-Specific Integrated Circuit), other chipsets, logic circuits, registers, communication modems, data processing devices, etc., known in the industry, in order to execute the various control logics performed in the present invention. Furthermore, when the control logic is implemented as software, the control unit 130 may be implemented as a collection of program modules. In this case, the program modules may be recorded in memory and executed by the control unit 130. The memory may be provided inside or outside the control unit 130 and may be connected to the control unit 130 by various well-known means.

[0076] The battery management device 100 may further include a storage unit 140. The storage unit 140 may store data and programs necessary for each component of the battery management device 100 to operate and function, or data generated during the process of operation and functioning. The type of storage unit 140 is not particularly limited, as long as it is a known information recording means that is known to be able to record, erase, update, and read data. For example, information storage means may include RAM (Random Access Memory), flash memory, ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), registers, etc. The storage unit 140 may also store program code in which the process that can be executed by the control unit 130 is defined.

[0077] Specifically, the memory unit 140 can store information necessary for the control unit 130 to diagnose the battery status. For example, the memory unit 140 can store the battery's open-circuit voltage, voltage history, battery differential profile DP, and reference profile RP. The control unit 130 can then access the memory unit 140 to obtain the information necessary for diagnosing the battery status.

[0078] The following describes a specific example in which the control unit 130 determines the voltage pattern.

[0079] The control unit 130 may be configured to calculate the voltage change rate based on the open-circuit voltage and the voltage history stored in advance. The control unit 130 may determine a voltage pattern for the measured open-circuit voltage (hereinafter referred to as the first open-circuit voltage) and one or more open-circuit voltages stored in the voltage history (hereinafter referred to as the second open-circuit voltage).

[0080] For example, the control unit 130 can analyze the pattern of open-circuit voltage over time through regression analysis of the first and second open-circuit voltages. As a result of the regression analysis, a regression model between time (or cycle) and open-circuit voltage can be derived. Here, the regression model can represent the rate of change of the open-circuit voltage with respect to time. For example, if y is the open-circuit voltage and x is time, the regression model may be a linear regression model represented by the linear equation "y = ax + b". As another example, the regression model may be a nonlinear regression model represented by a nonlinear equation. The control unit 130 can calculate the rate of change of voltage (rate of change of open-circuit voltage with respect to time) from the regression model.

[0081] Furthermore, the control unit 130 may be configured to compare the calculated voltage change rate with a preset reference rate of change and determine whether the battery voltage pattern is a decreasing pattern or a non-decreasing pattern.

[0082] Furthermore, the open-circuit voltage of the battery is included in the voltage history and can be used to determine the voltage pattern for the open-circuit voltage at the next point in time.

[0083] A battery management device 100 according to one embodiment of the present invention can determine the past history of the battery's open-circuit voltage and the voltage pattern relative to the open-circuit voltage measured at the present time using statistical techniques. That is, instead of considering only the open-circuit voltage at a specific point in time, the voltage pattern relative to the open-circuit voltage over the entire life cycle of the battery is used for diagnosing the battery's condition. Therefore, the battery management device 100 can track and diagnose the battery's condition.

[0084] On the other hand, the control unit 130 can determine the negative electrode peak and the positive electrode peak based on the peaks included in the reference profile RP and the peaks included in the differential profile DP.

[0085] The control unit 130 can compare the differential capacitance of the peaks included in the negative voltage band of the reference profile RP with the differential capacitance of the peaks included in the negative voltage band of the differential profile DP. The peak with the largest difference in differential capacitance can then be determined as the negative peak.

[0086] For example, referring to Figures 2 to 4, let's assume that the first peak p1 and the second peak p2 of differential profile DP are included in the negative voltage band of differential profile DP, and the first peak p1 and the second peak p2 of reference profile RP are included in the negative voltage band of reference profile RP. The control unit 130 can calculate the first differential capacitance difference (|d1-d1n|) between the first peaks p1 and the second differential capacitance difference (|d2-d2n|) between the second peaks p2. Then, if the first differential capacitance difference is greater than or equal to the second differential capacitance difference, the control unit 130 can determine the first peak p1 as the negative peak. Conversely, if the first differential capacitance difference is less than the second differential capacitance difference, the control unit 130 can determine the second peak p2 as the negative peak.

[0087] The control unit 130 can compare the differential capacitance of the peaks included in the positive voltage band of the reference profile RP with the differential capacitance of the peaks included in the positive voltage band of the differential profile DP. Then, it can determine the peak with the largest difference in differential capacitance as the positive peak.

[0088] For example, referring to Figures 2 to 4, we assume that the third peak p3, fourth peak p4, and fifth peak p5 of differential profile DP are included in the positive voltage band of differential profile DP, and the third peak p3, fourth peak p4, and fifth peak p5 of reference profile RP are included in the positive voltage band of reference profile RP. The control unit 130 can calculate the third differential capacitance difference (|d3-d3n|) between the third peaks p3, the fourth differential capacitance difference (|d4-d4n|) between the fourth peaks p4, and the fifth differential capacitance difference (|d5-d5n|) between the fifth peaks p5. Then, the control unit 130 can determine the peak with the largest differential capacitance difference among the third peak p3, fourth peak p4, and fifth peak p5 as the positive peak. For example, if the fifth differential capacitance difference is larger than the third differential capacitance difference and the fourth differential capacitance difference, the fifth peak p5 can be determined as the positive peak. If there are multiple peaks with the largest differential capacitance difference, the peak on the higher voltage side can be determined as the positive electrode peak.

[0089] The control unit 130 may be configured to adjust the pre-set operating conditions for the battery based on the diagnosed battery status.

[0090] As described above, the battery status can be diagnosed as either a positive electrode degradation state or a positive / negative electrode degradation state. Depending on the diagnosis result, the control unit 130 may adjust the battery usage conditions.

[0091] For example, the operating conditions set for a battery may include the charge termination voltage, discharge termination voltage, upper temperature limit, and upper limit of the charge / discharge C-rate. Adjusting the operating conditions according to the battery's condition can delay battery degradation. This is because changing the operating conditions allows the battery to escape from a vulnerable degradation environment (or cause of degradation).

[0092] For example, if the battery is diagnosed as having a degraded positive electrode, the control unit 130 can prevent a reaction from occurring on the high-potential side of the positive electrode by reducing the charging termination voltage. Furthermore, the control unit 130 can prevent the battery from reacting excessively by reducing the upper temperature limit. In other words, if the battery is diagnosed as having a degraded positive electrode, the control unit 130 can prevent further degradation of the positive electrode by reducing the charging termination voltage and / or the upper temperature limit.

[0093] As another example, if the battery is diagnosed as having a positive and negative electrode degradation state, the control unit 130 may prevent rapid charging from proceeding by reducing the upper limit of the charge / discharge C rate. On the other hand, a positive and negative electrode degradation state means a state in which both the positive and negative electrodes are degraded. Therefore, the control unit 130 may reduce the charge termination voltage and / or upper temperature limit, similar to when the battery is diagnosed as having a positive electrode degradation state.

[0094] A battery management device 100 according to one embodiment of the present invention can prevent further degradation of the battery by appropriately adjusting the operating conditions to correspond to the state of the battery. In other words, by adjusting the operating conditions of such a battery management device 100, the battery life can be increased.

[0095] A 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 components included in a conventional BMS. For example, the voltage acquisition unit 120, profile acquisition unit 110, control unit 130, and storage unit 140 of the battery management device 100 can be realized as components of a BMS.

[0096] 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 battery cells. The battery pack may further include electrical components (relays, fuses, etc.) and a case, etc.

[0097] Figure 5 shows an exemplary configuration of a battery pack according to another embodiment of the present invention.

[0098] The positive terminal of battery 11 may be connected to the positive terminal P+ of battery pack 10, and the negative terminal of battery 11 may be connected to the negative terminal P- of battery pack 10.

[0099] The measuring unit 12 can be connected to a first sensing line SL1, a second sensing line SL2, and a third sensing line SL3. Specifically, the measuring unit 12 can be connected to the positive terminal of the battery 11 through the first sensing line SL1 and to the negative terminal of the battery 11 through the second sensing line SL2. The measuring unit 12 can measure the voltage of the battery 11 based on the voltages measured in the first sensing line SL1 and the second sensing line SL2, respectively.

[0100] Furthermore, the measurement unit 12 can be connected to the current measurement unit A via the third sensing line SL3. For example, the current measurement unit A may be an ammeter or shunt resistor capable of measuring the charging current and discharging current of the battery 11. The measurement unit 12 can calculate the charge amount by measuring the charging current of the battery 11 via the third sensing line SL3. The measurement unit 12 can also calculate the discharge amount by measuring the discharge current of the battery 11 via the third sensing line SL3.

[0101] The load can be connected at one end to the positive terminal P+ of the battery pack 10 and at the other end to the negative terminal P- of the battery pack 10. Therefore, the positive terminal of the battery 11, the positive terminal P+ of the battery pack 10, the load, the negative terminal P- of the battery pack 10, and the negative terminal of the battery 11 can be electrically connected.

[0102] For example, the load may be a charging and discharging device, or it may be the motor of an electric vehicle that receives power from the battery 11.

[0103] Figure 6 is a schematic diagram showing an automobile 600 according to yet another embodiment of the present invention.

[0104] Referring to Figure 6, the battery pack 610 according to an embodiment of the present invention can be installed in an automobile 600 such as an electric vehicle (EV) or a hybrid vehicle (HV). Here, the battery pack 610 may be the battery pack 10 described above. The battery pack 610 can drive the automobile 600 by supplying power to the motor through an inverter provided in the automobile 600. Here, the battery pack 610 may include a battery management device 100. That is, the automobile 600 may include a battery management device 100.

[0105] Figure 7 is a schematic diagram illustrating a battery management method according to yet another embodiment of the present invention.

[0106] Preferably, each step of the battery management method can be performed by the battery management device 100. For the sake of clarity, the following will either omit or briefly explain any content that overlaps with the above explanation.

[0107] The voltage pattern determination step S100 is a step in which the voltage pattern of the battery is determined based on the open-circuit voltage of the battery and a previously stored voltage history, and can be performed by the control unit 130.

[0108] For example, the control unit 130 may compare the measured open-circuit voltage with one or more open-circuit voltages included in the voltage history. Specifically, the control unit 130 may determine the pattern of change in the open-circuit voltage over time. Here, the voltage pattern may be determined as a decreasing pattern or a non-decreasing pattern.

[0109] The peak determination step S200 is a step in which, if the determined voltage pattern is a predetermined pattern, a plurality of peaks are determined from a differential profile DP that shows the correspondence between the differential capacity and voltage of the battery, and can be performed by the control unit 130.

[0110] Preferably, the control unit 130 may be configured to determine multiple peaks from the differential profile DP when the determined voltage pattern is a decreasing pattern.

[0111] For example, in the embodiment shown in Figure 2, the control unit 130 can determine the first peak p1, the second peak p2, the third peak p3, the fourth peak p4, and the fifth peak p5 from the differential profile DP.

[0112] The electrode peak determination step S300 is a step in which the negative electrode peak and the positive electrode peak are determined from among the multiple peaks that have been determined, and can be performed by the control unit 130.

[0113] Here, the negative electrode peak is the peak that best represents the state of the battery's negative electrode, and the positive electrode peak is the peak that best represents the state of the battery's positive electrode. For example, in the embodiment shown in Figure 2, the first peak p1 may be determined as the negative electrode peak from among the first peak p1, second peak p2, third peak p3, fourth peak p4, and fifth peak p5, and the fifth peak p5 may be determined as the positive electrode peak.

[0114] The status diagnosis step S400 is a step of diagnosing the state of the battery by comparing the rate of change of the negative electrode peak with respect to a preset reference negative electrode peak and the rate of change of the positive electrode peak with respect to a preset reference positive electrode peak, and can be performed by the control unit 130.

[0115] Specifically, the control unit 130 can calculate the rate of change of the differential capacitance of the negative electrode peak by calculating the ratio of the differential capacitance of the negative electrode peak to a preset reference differential capacitance of the negative electrode. Furthermore, the control unit 130 can calculate the rate of change of the differential capacitance of the positive electrode peak by calculating the ratio of the differential capacitance of the positive electrode peak to a preset reference differential capacitance of the positive electrode.

[0116] The control unit 130 may be configured to diagnose the battery state as positive and negative electrode degradation if the rate of change of the differential capacity at the negative electrode peak exceeds the rate of change of the differential capacity at the positive electrode peak. Conversely, the control unit 130 may be configured to diagnose the battery state as positive electrode degradation if the rate of change of the differential capacity at the negative electrode peak is less than or equal to the rate of change of the differential capacity at the positive electrode peak.

[0117] 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.

[0118] 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.

[0119] 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]

[0120] 10: Battery Pack 11: Battery 12: Measuring part 100: Battery management device 110: Profile acquisition unit 120: Voltage acquisition unit 130: Control Unit 140: Storage section 600: Automobile 610: Battery Pack

Claims

1. A profile acquisition unit configured to acquire a differential profile showing the correspondence between the differential capacity and voltage of a battery, A voltage acquisition unit configured to acquire the open-circuit voltage of the aforementioned battery, A battery management device comprising: a control unit configured to determine the voltage pattern of the battery based on the open-circuit voltage and a pre-stored voltage history; if the determined voltage pattern is a predetermined pattern, to determine a plurality of peaks from the differential profile; to determine a negative electrode peak and a positive electrode peak from among the determined plurality of peaks; and to diagnose the state of the battery by comparing the rate of change of the negative electrode peak with respect to a pre-set reference negative electrode peak and the rate of change of the positive electrode peak with respect to a pre-set reference positive electrode peak.

2. The battery management device according to claim 1, wherein the control unit is configured to calculate the rate of change of the differential capacity of the negative electrode peak, calculate the rate of change of the differential capacity of the positive electrode peak, compare the rate of change of the differential capacity of the negative electrode peak and the rate of change of the differential capacity of the positive electrode peak, and diagnose the state of the battery according to the result of the comparison.

3. The battery management device according to claim 2, wherein the control unit is configured to calculate the ratio of the differential capacity of the negative electrode peak to a preset reference differential capacity of the negative electrode, calculate the rate of change of the differential capacity of the negative electrode peak, and calculate the ratio of the differential capacity of the positive electrode peak to a preset reference differential capacity of the positive electrode, calculate the rate of change of the differential capacity of the positive electrode peak.

4. The control unit, If the rate of change of the differential capacity of the negative electrode peak exceeds the rate of change of the differential capacity of the positive electrode peak, the state of the battery is diagnosed as a positive and negative electrode degradation state. The battery management device according to claim 2, wherein if the rate of change of the differential capacity of the negative electrode peak is less than or equal to the rate of change of the differential capacity of the positive electrode peak, the state of the battery is diagnosed as a positive electrode degradation state.

5. The battery management device according to claim 4, wherein the control unit is configured to adjust the usage conditions set in advance for the battery based on the state of the battery being diagnosed.

6. The battery management device according to claim 1, wherein the control unit is configured to calculate the voltage change rate based on the open-circuit voltage and a voltage history stored in advance, and to compare the calculated voltage change rate with a preset reference change rate to determine whether the battery voltage pattern is a decreasing pattern or a non-decreasing pattern.

7. The battery management device according to claim 6, wherein the control unit is configured to determine a plurality of peaks from the differential profile when the determined voltage pattern is a decreasing pattern.

8. The voltage acquisition unit is configured to acquire the open-circuit voltage after the battery has finished charging. The battery management device according to claim 1, wherein the profile acquisition unit is configured to acquire a differential profile showing the correspondence between the differential capacity and voltage of the battery during the charging process.

9. A battery pack including a battery management device according to any one of claims 1 to 8.

10. An automobile comprising a battery management device according to any one of claims 1 to 8.

11. A voltage pattern determination step in which the voltage pattern of the battery is determined based on the open-circuit voltage of the battery and the voltage history stored in advance, If the determined voltage pattern is a predetermined pattern, the process includes a peak determination step of determining multiple peaks from a differential profile showing the correspondence between the differential capacity and voltage of the battery, An electrode peak determination step in which the negative electrode peak and positive electrode peak are determined from among the multiple peaks that have been determined, A battery management method comprising: a state diagnosis step of diagnosing the state of the battery by comparing the rate of change of the negative electrode peak with respect to a preset reference negative electrode peak and the rate of change of the positive electrode peak with respect to a preset reference positive electrode peak.

Images