Battery management device and method

Abstract

A battery management apparatus according to the present disclosure includes: a curve obtaining unit configured to obtain a charge curve and a discharge curve representing charge characteristics and discharge characteristics of a battery; and a diagnosis unit configured to calculate a hysteresis characteristic value based on voltage difference information between the charging curve and the discharging curve in the target section, and compare the hysteresis characteristic value with a diagnosis value to diagnose a state of the battery.

Description

Battery management device and method Technical Field

[0001] This disclosure relates to battery management devices and methods capable of diagnosing battery status.

[0002] This application is based on and claims priority to Korean Patent Application No. 10-2024-0015098, filed with the Korean Intellectual Property Office on January 31, 2024, the disclosure of which is incorporated herein by reference in its entirety. Background Technology

[0003] Recently, demand for portable electronic products such as laptops, cameras, and mobile phones has increased dramatically, and electric vehicles, energy storage batteries, robots, and satellites have been vigorously developed. Therefore, high-performance batteries that allow for repeated charging and discharging are being actively researched.

[0004] Currently available batteries include nickel-cadmium (NiCd), nickel-metal hydride (NiMH), nickel-zinc (NiZn), and lithium-ion batteries. Among them, lithium-ion batteries have attracted much attention due to their virtually non-existent memory effect compared to nickel-based batteries, as well as their very low self-discharge rate and high energy density.

[0005] While much research has been conducted on these batteries in terms of high capacity and high density, improving lifespan and safety is also important. To enhance battery safety, a technology is needed to accurately diagnose the current state of the battery.

[0006] In an ideal charge and discharge cycle, the charging and discharging capacities of a battery can be the same. However, in actual charge and discharge cycles, these capacities may differ due to factors such as internal resistance. In other words, a battery exhibits a hysteresis characteristic, where its charging and discharging characteristics differ in actual charge and discharge cycles. The hysteresis characteristic is derived from the difference between the phase transition voltage that occurs during battery charging and the phase transition voltage that occurs during battery discharging. The hysteresis phenomenon may become more pronounced as the battery deteriorates or at higher charge / discharge rates (C-rates). Therefore, there is a need to develop a technique that can determine parameters representing the hysteresis characteristics of a battery and diagnose the battery's degradation state based on these determined parameters.

[0007] Furthermore, if charging and discharging characteristics in the 0% to 100% SOC range are necessary for diagnosing battery degradation, the diagnostic process may take an unnecessarily long time. Therefore, to shorten diagnostic time, it is necessary to develop technologies that can diagnose degradation using only charging and discharging characteristics for certain capacity ranges (or SOC ranges). Summary of the Invention

[0008] Technical issues

[0009] This disclosure aims to address the problems existing in the related art, and therefore, the purpose of this disclosure is to provide a battery management device and method that can diagnose the deterioration state of a battery based on hysteresis characteristic values, which are parameters representing the hysteresis characteristics of the battery.

[0010] In addition, this disclosure aims to provide a battery management device and method that can diagnose the state of a battery using only the charging and discharging characteristics of a portion of the battery's capacity (or state of charge).

[0011] These and other objects and advantages of this disclosure will become apparent from the following detailed description and will become even more fully apparent from exemplary embodiments of this disclosure. Moreover, it will be readily understood that the objects and advantages of this disclosure can be achieved by the means and combinations thereof as shown in the appended claims.

[0012] Technical solution

[0013] A battery management device according to one aspect of the present disclosure includes: a curve acquisition unit configured to acquire a charging curve and a discharging curve representing the charging and discharging characteristics of a battery; and a diagnostic unit configured to calculate a hysteresis value based on voltage difference information between the charging curve and the discharging curve in a target segment, and to compare the hysteresis value with a diagnostic value to diagnose the state of the battery.

[0014] The diagnostic unit can be configured to determine the target segment by comparing the capacity range of the charging curve with the capacity range of the discharging curve.

[0015] The diagnostic unit can be configured to identify all or part of the capacity segment common to the charging and discharging curves as the target segment.

[0016] The target segment can be predetermined.

[0017] The diagnostic unit can be configured to calculate the hysteresis characteristic value based on the integral of the voltage difference between the voltage of the charging curve and the voltage of the discharging curve for the target segment.

[0018] The battery management device may also include a storage unit.

[0019] The storage unit can store a lookup table in which multiple reference capacity segments and multiple diagnostic values ​​are mapped one-to-one.

[0020] The diagnostic unit can determine the reference value of one of the reference capacity segments corresponding to the target segment among multiple reference capacity segments as the diagnostic value.

[0021] The diagnostic unit can be configured to calculate diagnostic values ​​based on preset reference charging curves and preset reference discharging curves.

[0022] The diagnostic unit can be configured to determine diagnostic values ​​based on the integral of the voltage difference between the voltage of the reference charging curve and the voltage of the discharge curve of the target segment.

[0023] The diagnostic unit can diagnose the battery as being in a normal state when the difference between the hysteresis characteristic value and the diagnostic value is less than a preset first threshold.

[0024] The diagnostic unit can diagnose the battery state as abnormal when the difference between the hysteresis characteristic value and the diagnostic value is greater than or equal to a first threshold.

[0025] The diagnostic unit can diagnose the battery as being in a normal state when the ratio of the hysteresis characteristic value to the diagnostic value is less than a preset second threshold.

[0026] The diagnostic unit can diagnose the battery as an abnormal state when the ratio of the hysteresis characteristic value to the diagnostic value is greater than or equal to a preset second threshold.

[0027] The battery management device may also include a control unit.

[0028] The control unit can be configured to set battery usage based on diagnostic results.

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

[0030] A vehicle according to another aspect of this disclosure includes a battery management device according to one aspect of this disclosure.

[0031] A battery management method according to another aspect of this disclosure may include: obtaining charging and discharging curves representing the charging and discharging characteristics of the battery; calculating a hysteresis characteristic value based on voltage difference information between the charging and discharging curves in a target segment; and comparing the hysteresis characteristic value with diagnostic values ​​to diagnose the state of the battery.

[0032] Beneficial effects

[0033] According to at least one embodiment of the present disclosure, the degradation state of a battery can be diagnosed based on a hysteresis characteristic value, which is a parameter representing the hysteresis characteristic of the battery.

[0034] In addition, according to at least one embodiment of this disclosure, the time required for diagnosis can be shortened by diagnosing the state of the battery using only the charging and discharging characteristics for some capacity segments (or SOC segments) of the battery.

[0035] In addition, according to at least one embodiment of this disclosure, battery deterioration or accelerated deterioration can be prevented by appropriately setting the battery usage condition based on the battery status diagnostic results.

[0036] The effects of this disclosure are not limited to those described above, and other effects not mentioned will be clearly understood by those skilled in the art based on the description of the claims. Attached Figure Description

[0037] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, serve to provide a further understanding of the technical features of the present disclosure; therefore, the present disclosure is not to be construed as limited to the drawings.

[0038] Figure 1 is a schematic diagram illustrating a battery management device according to an embodiment of the present disclosure.

[0039] Figure 2 is a schematic diagram illustrating an example of a charging curve and a discharging curve.

[0040] Figure 3 is a diagram illustrating an exemplary configuration of a battery pack according to another embodiment of the present disclosure.

[0041] Figure 4 is a schematic diagram illustrating an exemplary configuration of a vehicle according to yet another embodiment of the present disclosure.

[0042] Figure 5 is a schematic diagram illustrating a battery management method according to another embodiment of the present disclosure.

[0043] Figure 6 is a schematic diagram illustrating a battery management method according to yet another embodiment of the present disclosure. Detailed Implementation

[0044] Before the description, it should be understood that the terms used in the specification and appended claims should not be construed as limited to their general and dictionary meanings, but rather as being interpreted based on the principle that the inventors are allowed to properly define terms for the best interpretation, and based on their meanings and concepts corresponding to the technical aspects of this disclosure.

[0045] Therefore, the description presented herein is merely the best preferred example for illustrative purposes only and is not intended to limit the scope of this disclosure. It should be understood that other equivalents and modifications may be made thereto without departing from the scope of this disclosure.

[0046] Furthermore, in interpreting this disclosure, if a detailed description of a relevant known structure or function is deemed likely to obscure the essential points of this disclosure, such detailed description will be omitted.

[0047] Ordinal terms such as “first” and “second” can be used to distinguish one element from another among the various elements, but are not intended to limit the elements by the terms.

[0048] Throughout this specification, when a section is referred to as “comprising” or “including” any element, it means that the section may also include other elements, without excluding other elements, unless otherwise specifically stated.

[0049] Furthermore, throughout the specification, when one part is referred to as "connected" to another part, it is not limited to the case where they are "directly connected," but also includes the case where they are "indirectly connected" by another element inserted between them.

[0050] In the following, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0051] Figure 1 is a schematic diagram illustrating a battery management device 100 according to an embodiment of the present disclosure.

[0052] Referring to FIG1, a battery management device 100 according to an embodiment of the present disclosure may include a curve acquisition unit 110 and a diagnostic unit 120, and may also include a control unit 130. The battery management device 100 may also include a storage unit 140.

[0053] A battery management device 100 is provided to diagnose the state of the battery (see symbol 11 in Figure 3). Depending on the embodiment, the battery management device 100 may be configured to be organically linked with other configurations or modules / devices to generate and output diagnostic data for the battery.

[0054] Here, a battery refers to a physically separable, independent single unit with a negative and a positive terminal. For example, a lithium-ion cell or a lithium polymer cell can be considered a battery. Additionally, the type of battery can be cylindrical, prismatic, or pouch-type. Furthermore, a battery can refer to a battery bank, battery module, or battery pack in which multiple battery cells are connected in series and / or parallel. In the following text, for ease of explanation, a battery is interpreted as referring to a single, independent unit.

[0055] Figure 2 is a schematic diagram illustrating an example of a charging curve CP and a discharging curve DP.

[0056] In the embodiment of Figure 2, the horizontal axis (X-axis) represents capacity (mAh) and the vertical axis (Y-axis) represents voltage (V).

[0057] The curve acquisition unit 110 can be configured to acquire a charging curve CP and a discharging curve DP representing the charging and discharging characteristics of the battery.

[0058] A charging curve (CP) represents the relationship between voltage and capacity (or SOC: state of charge, resistance) during battery charging. For example, the charging process can be performed according to a CC-CV (constant current-constant voltage) charging protocol. The magnitude of the charging current for CC charging and the magnitude of the charging voltage for CV charging can be predetermined. The charging protocol used to obtain the charging curve CP periodically or non-periodically throughout the battery's lifespan can be the same as the charging protocol used to obtain the reference charging curve described later. The type of charging protocol is not limited to the CC-CV charging protocol if the capacity-voltage characteristics of the battery during charging can be obtained.

[0059] Furthermore, the discharge curve DP can represent the relationship between voltage and capacity (or SOC, resistance) during battery discharge. For example, the discharge process can be performed according to a CC (constant current) discharge protocol. The magnitude of the discharge current used for CC discharge can be predetermined. The discharge protocol used to obtain the discharge curve DP periodically or non-periodically throughout the battery's lifespan can be the same as the discharge protocol used to obtain the reference discharge curve described later. If the capacity-voltage characteristics of the battery during discharge can be obtained, the type of discharge protocol is not limited to a CC discharge protocol.

[0060] In this specification, obtaining any data or information should be understood to mean receiving it from external devices via a communication device, inputting it from a user via an input device, or creating it by executing a program.

[0061] For example, the curve acquisition unit 110 can be connected to an external device via wired and / or wireless means to directly receive the charging curve CP and the discharging curve DP. Wired communication can be, for example, CAN (Controller Area Network) communication or CAN-FD (CAN with Flexible Data Rate). Wireless communication can be, for example, Zigbee or Bluetooth communication. Of course, the type of communication protocol is not particularly limited, as long as it supports communication between the curve acquisition unit 110 and the external device.

[0062] As another example, the curve acquisition unit 110 can receive measurement information representing the voltage and current of the battery. The curve acquisition unit 110 can then generate a charging curve CP and a discharging curve DP based on the received measurement information.

[0063] For example, the curve acquisition unit 110 can generate a charging curve CP and a discharging curve DP by performing a process that maps the battery's voltage time series and capacity time series (or SOC time series, resistance time series) to each other based on time indices. The charging curve CP and discharging curve DP can be a set of data points or a polynomial representing the correspondence between the battery's voltage and capacity (or SOC, resistance). Each data point in the charging curve CP and discharging curve DP can be a pair of voltage and capacity values ​​(or SOC, resistance values) indexed at the same time point (same measurement timing).

[0064] Voltage time series can represent the history of a battery's voltage changes over time. Current time series can represent the history of a battery's current changes over time. Capacity time series (or State of Charge (SOC) time series) can be determined by applying ampere counting to the current time series. Resistance time series can be determined by applying Ohm's law to the battery's voltage and current.

[0065] State of Charge (SOC) is a parameter representing the current capacity relative to 0% to 100% of the maximum capacity, and can be calculated using various techniques such as current integration, equivalent circuit models, and Kalman filters. Depending on the embodiment, the battery management device 100 can be configured to generate information about the SOC by further reflecting environmental information such as temperature information.

[0066] The curve acquisition unit 110 can be connected to the diagnostic unit 120 for communicative connection. For example, the curve acquisition unit 110 can be connected to the diagnostic unit 120 via wired and / or wireless means. The curve acquisition unit 110 can transmit the acquired charging curve CP and discharging curve DP to the diagnostic unit 120.

[0067] The diagnostic unit 120 can be configured to calculate a hysteresis characteristic value based on the voltage difference information between the charging curve CP and the discharging curve DP in the target segment. The time interval between the end time of one of the charging and discharging processes and the start time of another process executed to obtain the charging curve CP and discharging curve DP for calculating the hysteresis characteristic value can be less than a predetermined threshold time. For example, the time interval between the end time of the charging process that obtains the charging curve CP and the start time of the discharging process that obtains the discharging curve DP can be less than the threshold time. In this case, the corresponding discharging process can be executed after the corresponding charging process. As another example, the time interval between the end time of the discharging process that obtains the discharging curve DP and the start time of the charging process that obtains the charging curve CP can be less than the threshold time. In this case, the corresponding charging process can be executed after the corresponding discharging process.

[0068] Together or separately, the battery’s charging and discharging capacity may be less than the threshold capacity during the time between the end of one charging process and the start of another.

[0069] In one embodiment, the diagnostic unit 120 may be configured to determine the target segment TS by comparing the capacity range (or SOC range, resistance range) of the charging curve CP with the capacity range (or SOC range, resistance range) of the discharging curve DP.

[0070] The target segment TS can be all or part of the capacity segment shared by the charging curve CP and the discharging curve DP. For example, the diagnostic unit 120 can determine the larger value between the minimum capacity of the charging curve CP and the minimum capacity of the discharging curve DP as the lower limit of the target segment TS. If the minimum capacity of the charging curve CP and the minimum capacity of the discharging curve DP are the same, then the diagnostic unit 120 can determine the minimum capacity of either the charging curve CP or the discharging curve DP as the lower limit of the target segment TS.

[0071] Furthermore, the diagnostic unit 120 can determine the smaller of the maximum capacity of the charging curve CP and the maximum capacity of the discharging curve DP as the upper limit of the target segment TS. If the maximum capacity of the charging curve CP and the maximum capacity of the discharging curve DP are the same, the diagnostic unit 120 can determine either the maximum capacity of the charging curve CP or the maximum capacity of the discharging curve DP as the upper limit of the target segment TS.

[0072] In the embodiment of Figure 2, the diagnostic unit 120 can determine the minimum capacity (Q) of the charging curve CP. C_min ) and maximum capacity (Q C_max ), and determine the minimum capacity (Q) of the discharge curve DP. D_min ) and maximum capacity (Q D_max Additionally, the diagnostic unit 120 can determine the minimum capacity (Q) of the charging curve CP. C_min ) and the minimum capacity (Q) of the discharge curve DP. D_min The larger value among them (Q) D_min The lower limit of the target segment TS is determined. The diagnostic unit 120 can determine the maximum capacity (Q) of the charging curve CP. C_max ) and the maximum capacity of the discharge curve DP (Q D_max The smaller value among them (Q) C_max The upper limit of the target segment TS is determined. In other words, the diagnostic unit 120 can determine Q. D_min To Q C_max The capacity segment is determined as the target segment TS.

[0073] Similarly, the diagnostic unit 120 can be configured to determine that the target segment TS is equal to the common SOC range of the charge curve CP and the discharge curve DP. In this case, the target segment TS can represent the SOC segment.

[0074] If the charging curve CP and the discharging curve DP represent the correspondence between the battery's voltage and resistance, then the diagnostic unit 120 can be configured to determine that the target segment TS is equal to the common resistance range of the charging curve CP and the discharging curve DP. In this case, the target segment TS can represent a resistance segment.

[0075] In another embodiment, a target segment TS can be predetermined. Specifically, the target segment TS can be a predetermined capacity segment, a state of charge (SOC) segment, or a resistance segment. For example, the target segment TS can be an SOC segment in which the hysteresis characteristics change significantly to a certain level or more as the battery deteriorates (e.g., 40% to 60%), and can be a segment confirmed by multiple previous experiments.

[0076] The diagnostic unit 120 can be configured to calculate a hysteresis characteristic value based on the integral of the voltage difference between the voltage of the charging curve CP and the voltage of the discharging curve DP relative to the target segment TS. In this case, the hysteresis characteristic value represents the area of ​​the closed curve defined by the charging curve CP, the discharging curve DP, and the target segment TS, and can be defined as one of the degradation parameters used to assess the degradation state of the battery.

[0077] For example, the diagnostic unit 120 can calculate the voltage difference between the voltage value of the charging curve CP and the voltage value of the discharging curve DP corresponding to the same capacity within the target segment TS. Then, the diagnostic unit 120 can determine the integral of the voltage difference in the target segment TS as the hysteresis characteristic value.

[0078] In the embodiment of Figure 2, the diagnostic unit 120 can calculate any capacity (Q) corresponding to the target segment TS. x The voltage value (V) of the charging curve CP. C (Q) x The voltage value (V) of the discharge curve DP D (Q) x The voltage difference between (i.e., V) C (Q) x -V D (Q) x Then, the diagnostic unit 120 can determine the integral of the voltage difference in the target segment TS as the hysteresis characteristic value.

[0079] For example, the diagnostic unit 120 can use Formula 1 to determine the hysteresis characteristic value.

[0080] [Formula 1]

[0081] Here, H represents the hysteresis characteristic value, and V C (Q) represents the voltage value corresponding to the capacity Q in the charging curve CP, and V D (Q) represents the voltage value corresponding to the capacity Q in the discharge curve DP.

[0082] The diagnostic unit 120 can be configured to diagnose the state of the battery by comparing the hysteresis characteristic value with the diagnostic value.

[0083] The diagnostic value is a parameter to be compared with the battery's hysteresis characteristic value. It can be determined from multiple preset reference values, or it can be determined based on preset reference charging curves and reference discharging curves. The following describes a specific example of how the diagnostic unit 120 determines the diagnostic value.

[0084] The diagnostic unit 120 can diagnose the battery's state as either normal or abnormal. Here, an abnormal state can refer to a state where the hysteresis characteristic value, determined based on the charging curve CP and the discharging curve DP, becomes greater than a predetermined value as the battery deteriorates. As the battery deteriorates, its internal resistance increases, and the hysteresis characteristic value has a strong positive correlation with the battery's internal resistance. Therefore, an abnormal state can refer to a state where the battery's internal resistance becomes greater than a predetermined value. In other words, an abnormal state can be understood as a state where the battery is excessively deteriorated and requires appropriate control for safe and long-term battery use thereafter.

[0085] In one embodiment, the diagnostic unit 120 can diagnose the battery state based on the difference between the hysteresis characteristic value and the diagnostic value. For example, if the difference between the hysteresis characteristic value and the diagnostic value is less than a preset first threshold, the diagnostic unit 120 can be configured to diagnose the battery state as normal. As another example, if the difference between the hysteresis characteristic value and the diagnostic value is greater than or equal to the first threshold, the diagnostic unit 120 can be configured to diagnose the battery state as abnormal. The difference between the hysteresis characteristic value and the diagnostic value tends to increase as the battery deteriorates. Therefore, the difference between the hysteresis characteristic value and the diagnostic value can be considered an indicator of the degree of battery deterioration.

[0086] In another embodiment, the diagnostic unit 120 can diagnose the battery state based on the ratio between the hysteresis characteristic value and the diagnostic value. For example, if the ratio of the hysteresis characteristic value to the diagnostic value is less than a preset second threshold, the diagnostic unit 120 can be configured to diagnose the battery state as normal. As another example, if the ratio of the hysteresis characteristic value to the diagnostic value is greater than or equal to the second threshold, the diagnostic unit 120 can be configured to diagnose the battery state as abnormal. The ratio of the hysteresis characteristic value to the diagnostic value tends to increase as the battery deteriorates. Therefore, the ratio of the hysteresis characteristic value to the diagnostic value can be regarded as an indicator of the degree of battery deterioration.

[0087] The battery management device 100 diagnoses the battery's state based on the hysteresis characteristic value in the target segment TS. Therefore, it is not necessary to charge and discharge the entire segment (e.g., the SOC 0% to 100% segment) for state diagnosis. In other words, the battery's state can be diagnosed using only the charge and discharge characteristics of a portion of the battery's capacity segment (or SOC segment), thereby reducing the time required for diagnosis.

[0088] Meanwhile, the curve acquisition unit 110, diagnostic unit 120, and control unit 130 included in the battery management device 100 may optionally include processors, application-specific integrated circuits (ASICs), other chipsets, logic circuits, registers, communication modems, data processing devices, etc., known in the art, to execute the various control logics performed in this disclosure. Furthermore, when the control logic is implemented as software, the curve acquisition unit 110, diagnostic unit 120, and control unit 130 can be implemented as a collection of program modules. In this case, the program modules can be stored in memory and executed by the curve acquisition unit 110, diagnostic unit 120, and control unit 130. The memory can be internal or external to the battery management device 100 and can be connected to the curve acquisition unit 110, diagnostic unit 120, and control unit 130 via various known devices.

[0089] Additionally, the battery management device 100 may also include a storage unit 140. The storage unit 140 may store data required for the operation and function of various components of the battery management device 100, data generated during the execution of operations or functions, etc. There are no particular limitations on the type of storage unit 140; it can be any known information storage device capable of recording, erasing, updating, and retrieving data. As examples, the information storage device may include RAM, flash memory, ROM, EEPROM, registers, etc. Furthermore, the storage unit 140 may store program code that defines the processes that can be executed by the curve acquisition unit 110, the diagnostic unit 120, and the control unit 130.

[0090] Specifically, storage unit 140 can store the information required by curve acquisition unit 110 to obtain charging curve CP and discharging curve DP. Storage unit 140 can store the information required by diagnostic unit 120 to calculate hysteresis characteristic value. In addition, storage unit 140 can store the information required by diagnostic unit 120 to diagnose battery state by comparing hysteresis characteristic value with diagnostic value. For example, storage unit 140 can store charging curve CP, discharging curve DP, hysteresis characteristic value, diagnostic value, target segment TS, lookup table, reference charging curve, reference discharging curve, first threshold, second threshold, etc. In addition, curve acquisition unit 110, diagnostic unit 120 and control unit 130 can access storage unit 140 to obtain necessary information.

[0091] Below is a specific example of how the diagnostic unit 120 determines diagnostic values.

[0092] For example, storage unit 140 may store a lookup table in which multiple reference capacity segments are mapped one-to-one with multiple reference values. Diagnostic unit 120 may be configured to determine the reference value of a reference capacity segment corresponding to the target segment TS among the multiple reference capacity segments as a diagnostic value.

[0093] In the embodiment of Figure 2, the diagnostic unit 120 can determine the target segment (TS, Q) among multiple reference capacity segments of the lookup table. D_min To Q C_max This corresponds to a reference capacity range. For example, the lower limit of the reference capacity range could be Q. D_min And the upper limit can be Q. C_max The diagnostic unit 120 can map to a reference capacity segment (Q) corresponding to the target segment TS. D_min To Q C_max A reference value for Q is determined as the diagnostic value. That is, the diagnostic unit 120 can match the determined reference capacity segment (Q) in the lookup table. D_min To Q C_max The corresponding reference value is determined as the diagnostic value.

[0094] As another example, the diagnostic unit 120 can be configured to generate diagnostic values ​​based on a reference charging curve and a reference discharging curve.

[0095] Specifically, the diagnostic unit 120 can be configured to determine a diagnostic value based on the integral of the voltage difference between the voltage of the reference charging curve and the voltage of the discharge curve DP relative to the target segment TS.

[0096] The reference charging curve can be a curve that shows the relationship between voltage and capacity (or SOC, resistance) obtained during charging when the reference battery corresponding to the battery to be diagnosed is in the BOL (Start of Life) state.

[0097] The reference discharge curve can be a curve that shows the relationship between voltage and capacity (or SOC, resistance) obtained during discharge when a reference battery corresponding to the battery to be diagnosed is in the BOL state.

[0098] The reference charging curve and the reference discharging curve can be pre-recorded in the storage unit 140.

[0099] As described above, the method by which the diagnostic unit 120 determines the diagnostic value based on the integral of the voltage difference between the reference charging curve and the discharging curve DP relative to the target segment TS is the same as the method by which the diagnostic unit 120 determines the hysteresis characteristic value based on the integral of the voltage difference between the charging curve CP and the discharging curve DP relative to the target segment TS.

[0100] Specifically, the diagnostic unit 120 can calculate the voltage difference between the voltage value of a reference charging curve and the voltage value of a reference discharging curve corresponding to the same capacity within the target segment TS. Furthermore, the diagnostic unit 120 can determine the integral of the voltage difference within the target segment TS as a diagnostic value.

[0101] Diagnostic unit 120 can calculate any capacity (Q) in the target segment TS. x The voltage difference between the voltage value of the reference charging curve and the voltage value of the discharge curve DP is then used as the diagnostic value. The diagnostic unit 120 can then determine the integral of the voltage difference in the target segment TS as the diagnostic value.

[0102] For example, the diagnostic unit 120 can use Formula 2 to determine the diagnostic value.

[0103] [Formula 2]

[0104] Where D represents the diagnostic value, V RCP (Q) represents the voltage value of the corresponding reference charging curve when the capacity is Q, and V RDP (Q) represents the voltage value of the corresponding reference discharge curve when the capacity is Q.

[0105] The battery management device 100 may also include a control unit 130. The control unit 130 may be configured to set the battery usage status based on diagnostic results.

[0106] If the battery is diagnosed as being in a normal state, the control unit 130 may not change the battery's operating conditions. Conversely, if the battery is diagnosed as being in an abnormal state, the control unit 130 may change the battery's operating conditions.

[0107] For example, control unit 130 can reduce the maximum charge / discharge rate of the battery. As another example, control unit 130 can reduce the battery's charge termination voltage. The charge termination voltage can refer to the allowable termination voltage when charging the battery. As another example, control unit 130 can increase the battery's discharge termination voltage. The discharge termination voltage can refer to the minimum allowable voltage when discharging the battery.

[0108] The rate of decrease in maximum charge / discharge rate, the rate of decrease in end-of-charge voltage, or the rate of increase in end-of-discharge voltage can be determined as a proportion to the difference or ratio between the battery's hysteresis characteristic value and the diagnostic value. For example, when the ratio of the battery's hysteresis characteristic value to the diagnostic value is 1.1, the maximum charge and discharge rates can be set to a decrease of 1 / 1.1 compared to before.

[0109] According to embodiments of the present disclosure, the battery management device 100 can prevent or accelerate battery degradation by appropriately setting the battery usage status based on battery status diagnostic results.

[0110] The battery management device 100 according to this disclosure can be applied to a battery management system (BMS). That is, the BMS according to this disclosure can include the aforementioned battery management device 100. In this configuration, at least some components of the battery management device 100 can be implemented by supplementing or adding the functions of components included in a conventional BMS. For example, the curve acquisition unit 110, diagnostic unit 120, control unit 130, and storage unit 140 of the battery management device 100 can be implemented as components of a BMS.

[0111] The battery management device 100 according to this disclosure can be disposed in a battery pack. That is, the battery pack 10 according to this disclosure may include the aforementioned battery management device 100 and at least one battery. In addition, the battery pack may also include electrical components (relays, fuses, etc.) and a housing.

[0112] Figure 3 is a schematic diagram illustrating an exemplary configuration of a battery pack 10 according to another embodiment of the present disclosure.

[0113] The positive terminal of battery 11 can be connected to the positive terminal P+ of battery pack 10, and the negative terminal of battery 11 can be connected to the negative terminal P- of battery pack 10.

[0114] 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 via the first sensing line SL1 and to the negative terminal of the battery 11 via the second sensing line SL2. The measuring unit 12 can measure the voltage of the battery 11 based on the voltage measured from each of the first sensing line SL1 and the second sensing line SL2.

[0115] Additionally, 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 can be an ammeter or a shunt resistor capable of measuring the charging and discharging currents 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. Furthermore, the measurement unit 12 can calculate the discharge amount by measuring the discharging current of the battery 11 via the third sensing line SL3.

[0116] One end of an external device (not shown) can be connected to the positive terminal P+ of battery pack 10, and the other end can be connected to the negative terminal P- of battery pack 10. Therefore, the positive terminal of battery 11, the positive terminal P+ of battery pack 10, the external device, the negative terminal P- of battery pack 10, and the negative terminal of battery 11 can be electrically connected.

[0117] For example, an external device could be a charging device or load that receives power from battery 11, such as the electric motor of an electric vehicle.

[0118] Figure 4 is a schematic diagram illustrating a vehicle 1 according to yet another embodiment of the present disclosure.

[0119] Referring to FIG4, the battery pack 10 according to an embodiment of the present disclosure can be included in a vehicle 1, such as an electric vehicle (EV) or a hybrid vehicle (HV). Here, the aforementioned battery pack 10 can be applied to a battery pack 10. Additionally, the battery pack 10 can supply power to a motor via an inverter disposed in the vehicle 1 to drive the vehicle 1. Here, the battery pack 10 can include a battery management device 100 according to an embodiment of the present disclosure. That is, the vehicle 1 can include the battery management device 100. In this case, the battery management device 100 can be an on-board device included in the vehicle 1.

[0120] Figure 5 is a schematic diagram illustrating a battery management method according to yet another embodiment of the present disclosure.

[0121] Preferably, each step of the battery management method can be performed by the battery management device 100. In the following description, for ease of explanation, content overlapping with the previously described content will be briefly described or omitted.

[0122] Referring to Figure 5, in step S510, the curve obtaining unit 110 can obtain the charging curve CP and the discharging curve DP, which represent the charging and discharging characteristics of the battery.

[0123] A charging curve can represent the relationship between voltage and capacity (or SOC: state of charge, resistance) during the charging process of a battery. Similarly, a discharging curve can represent the relationship between voltage and capacity (or SOC, resistance) during the discharging process of a battery.

[0124] In step S520, the diagnostic unit 120 can calculate the hysteresis characteristic value based on the voltage difference information between the charging curve CP and the discharging curve DP in the target segment TS.

[0125] For example, the diagnostic unit 120 can be configured to determine the target segment TS by comparing the capacity range (or SOC range, resistance range) of the charging curve CP with the capacity range (or SOC range, resistance range) of the discharging curve DP.

[0126] As another example, the target portion TS can be predetermined.

[0127] The diagnostic unit 120 can be configured to calculate the hysteresis characteristic value based on the integral of the voltage difference between the voltage of the charging curve CP and the voltage of the discharging curve DP relative to the target segment TS.

[0128] In step S530, the diagnostic unit 120 can diagnose the state of the battery by comparing the hysteresis characteristic value with the diagnostic value.

[0129] In one embodiment, the diagnostic unit 120 can diagnose the battery state based on the difference between the hysteresis characteristic value and the diagnostic value. For example, if the difference between the hysteresis characteristic value and the diagnostic value is less than a preset first threshold, the diagnostic unit 120 can be configured to diagnose the battery state as normal. As another example, if the difference between the hysteresis characteristic value and the diagnostic value is greater than or equal to the first threshold, the diagnostic unit 120 can be configured to diagnose the battery state as abnormal.

[0130] In another embodiment, the diagnostic unit 120 can diagnose the battery state based on the ratio between the hysteresis characteristic value and the diagnostic value. For example, if the ratio of the hysteresis characteristic value to the diagnostic value is less than a preset second threshold, the diagnostic unit 120 can be configured to diagnose the battery state as normal. As another example, if the ratio of the hysteresis characteristic value to the diagnostic value is greater than or equal to the second threshold, the diagnostic unit 120 can be configured to diagnose the battery state as abnormal.

[0131] Figure 6 is a schematic diagram illustrating a battery management method according to yet another embodiment of the present disclosure.

[0132] Any content that overlaps with the content previously described with reference to Figure 5 is omitted or briefly explained.

[0133] Referring to Figure 6, in step S610, the curve obtaining unit 110 can obtain the charging curve CP and the discharging curve DP, which represent the charging and discharging characteristics of the battery.

[0134] In step S620, the diagnostic unit 120 can determine the target segment TS by comparing the capacity range of the charging curve CP and the capacity range of the discharging curve DP.

[0135] For example, the diagnostic unit 120 can be configured to determine a target segment TS by comparing the capacity range of the charging curve CP with the capacity range of the discharging curve DP. The target segment TS can be all or part of a capacity segment shared by the charging curve CP and the discharging curve DP.

[0136] In step S630, the diagnostic unit 120 can calculate the hysteresis characteristic value based on the voltage difference information between the charging curve CP and the discharging curve DP in the target segment TS.

[0137] In step S640, the diagnostic unit 120 can calculate the diagnostic value in the target segment TS.

[0138] In one embodiment, the diagnostic unit 120 can determine the reference value mapped to a reference capacity segment corresponding to the target segment TS among a plurality of reference capacity segments as the diagnostic value.

[0139] In another embodiment, the diagnostic unit 120 may calculate diagnostic values ​​based on preset reference charging curves and reference discharging curves.

[0140] For example, the diagnostic unit 120 can be configured to determine a diagnostic value based on the integral of the voltage difference between the voltage of the reference charging curve and the voltage of the discharge curve DP relative to the target segment TS.

[0141] For example, the diagnostic unit 120 can calculate the voltage difference between the voltage value of a reference charging curve and the voltage value of a reference discharging curve corresponding to the same capacity within the target segment TS. Then, the diagnostic unit 120 can determine the integral of the voltage difference in the target segment TS as a diagnostic value.

[0142] In step S650, the diagnostic unit 120 can diagnose the state of the battery by comparing the hysteresis characteristic value with the diagnostic value.

[0143] The embodiments of this disclosure described above can be implemented not only by apparatus and methods, but also by a program that implements functions corresponding to the configuration of the embodiments of this disclosure, or a recording medium that records the program. Those skilled in the art can readily implement such a program or recording medium from the description of the above embodiments.

[0144] This disclosure has been described in detail. However, it should be understood that while the detailed description and specific examples indicate preferred embodiments of this disclosure, they are given by way of illustration only, as various changes and modifications within the scope of this disclosure will become apparent to those skilled in the art from the detailed description.

[0145] Furthermore, without departing from the technical aspects of this disclosure, those skilled in the art can make many substitutions, modifications and changes to this disclosure, and this disclosure is not limited to the above embodiments and drawings, and each embodiment can be selectively combined in part or in whole to allow various modifications.

[0146] [Explanation of reference numerals in the attached diagram]

[0147] 1: Electric vehicles

[0148] 10: Battery Pack

[0149] 100: Battery Management Device

[0150] 110: Curve Acquisition Unit

[0151] 120: Diagnostic Unit

[0152] 130: Control Unit

[0153] 140: Storage unit

Claims

1. A battery management device, comprising: A curve acquisition unit is configured to acquire charging curves and discharging curves representing the charging and discharging characteristics of a battery. The diagnostic unit is configured to calculate a hysteresis characteristic value based on the voltage difference information between the charging curve and the discharging curve in the target segment, and compare the hysteresis characteristic value with a diagnostic value to diagnose the state of the battery.

2. The battery management device according to claim 1, wherein, The diagnostic unit is configured to determine the target segment by comparing the capacity range of the charging curve with the capacity range of the discharging curve.

3. The battery management device according to claim 2, wherein, The diagnostic unit is configured to identify all or part of the capacity segment shared by the charging curve and the discharging curve as the target segment.

4. The battery management device according to claim 1, wherein, The target section is predetermined.

5. The battery management device according to claim 1, wherein, The diagnostic unit is configured to calculate the hysteresis value based on the integral of the voltage difference between the voltage of the charging curve and the voltage of the discharging curve for the target segment.

6. The battery management device according to claim 1, further comprising a storage unit, wherein, The storage unit stores a lookup table in which multiple reference capacity segments are mapped one-to-one with multiple diagnostic values. The diagnostic unit determines the diagnostic value as the reference value of one of the reference capacity segments mapped to the target segment.

7. The battery management device according to claim 1, wherein, The diagnostic unit is configured to calculate the diagnostic value based on a preset reference charging curve and a preset reference discharging curve.

8. The battery management device according to claim 7, wherein, The diagnostic unit is configured to determine the diagnostic value based on the integral of the voltage difference between the voltage of the reference charging curve and the voltage of the discharge curve for the target segment.

9. The battery management device according to claim 1, wherein, The diagnostic unit diagnoses the battery state as normal when the difference between the hysteresis characteristic value and the diagnostic value is less than a preset first threshold; wherein, the diagnostic unit diagnoses the battery state as abnormal when the difference between the hysteresis characteristic value and the diagnostic value is greater than or equal to the first threshold.

10. The battery management device according to claim 1, wherein, The diagnostic unit diagnoses the battery state as normal when the ratio of the hysteresis characteristic value to the diagnostic value is less than a preset second threshold, and diagnoses the battery state as abnormal when the ratio of the hysteresis characteristic value to the diagnostic value is greater than or equal to the preset second threshold.

11. The battery management device according to claim 1, further comprising a control unit, wherein, The control unit is configured to set the battery usage status based on the diagnostic results.

12. A battery pack comprising a battery management device according to any one of claims 1 to 11.

13. A vehicle comprising a battery management device according to any one of claims 1 to 11.

14. A battery management method, comprising: Obtain charging and discharging curves that represent the charging and discharging characteristics of the battery; The hysteresis characteristic value is calculated based on the voltage difference information between the charging curve and the discharging curve in the target segment; and the hysteresis characteristic value is compared with the diagnostic value to diagnose the state of the battery.

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