Battery management device, battery pack, and battery management method

Abstract

An object of the present application is to provide a battery management device and a battery management method in which an optimal upper limit C-rate corresponding to a battery cell is determined to prevent lithium plating from occurring in the battery cell. Specifically, according to one aspect of the present application, the charging and discharging of the battery cell can be controlled in accordance with the determined upper limit C-rate, and thus it is possible to prevent side reactions from occurring in the battery cell due to charging and discharging at a high C-rate. Furthermore, the deterioration of the battery cell progresses slowly, and thus it is possible to increase the life of the battery cell.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2020-0153903, filed in Korea on November 17, 2020, the disclosure of which is incorporated herein by reference.

[0002] This disclosure relates to a battery management device, battery pack, and battery management method, and more specifically, to a battery management device, battery pack, and battery management method capable of setting an upper limit C-rate for battery cells. 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 are also developing rapidly. 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 these, 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-charge rate and high energy density.

[0005] Generally, batteries can gradually degrade due to side reactions during repeated charging and discharging. For example, when charging and / or discharging at a high C- rate, lithium plating may occur, where lithium deposits on the negative electrode of the battery. When lithium plating occurs in the battery, the negative electrode capacity is lost, thus potentially reducing battery life.

[0006] Traditionally, the occurrence and timing of lithium plating are diagnosed by analyzing battery curves. However, in the case of degraded batteries with increased internal resistance due to degradation, accurate diagnosis of the timing is difficult. Furthermore, in related technologies, diagnosing whether and when lithium plating occurred after it has already happened limits the ability to prevent lithium plating from occurring in batteries. Summary of the Invention

[0007] Technical issues

[0008] This disclosure is designed to address the problems in the related technologies, and therefore aims to provide a battery management device and method that can prevent lithium plating in a battery cell by determining an optimal upper limit C-rate corresponding to the battery cell.

[0009] These and other objects and advantages of this disclosure may be understood from the following detailed description and will become even clearer from exemplary embodiments of this disclosure. Furthermore, it will be readily understood that the objects and advantages of this disclosure can be achieved by the means shown in the appended claims and combinations thereof.

[0010] Technical solution

[0011] According to one aspect of the present disclosure, a battery management device manages battery cells that are charged multiple times at each of a plurality of C-rates. The battery management device may include: a curve generation unit configured to obtain a plurality of battery curves representing the correspondence between the voltage and capacity of the battery cells for each of the plurality of C-rates, and to generate a plurality of differential curves representing the correspondence between the voltage of the battery cells and the differential capacity for that voltage based on each of the obtained plurality of battery curves; and a control unit configured to obtain the plurality of differential curves from the curve generation unit, classify the plurality of differential curves into a standard differential curve corresponding to a preset standard C-rate and a plurality of reference differential curves, determine a standard peak value in the standard differential curves, determine a reference peak value in each of the plurality of reference differential curves, compare the voltage of the determined standard peak value with the voltage of the determined plurality of reference peak values, and determine an upper limit C-rate for the battery cells based on the comparison result.

[0012] The control unit can be configured to calculate the voltage difference between a standard peak and each of a plurality of reference peaks, compare the calculated plurality of voltage differences with a preset threshold voltage, and determine an upper limit C-rate based on the comparison results.

[0013] The control unit can be configured to determine a reference peak value where the calculated voltage difference is equal to or greater than a threshold voltage as the target peak value, and to determine the C-rate corresponding to a reference differential curve including the determined target peak value as the upper limit C-rate.

[0014] The control unit can be configured to generate voltage curves representing the correspondence between multiple voltage differences and multiple C-rates, and to determine the target C-rate corresponding to the threshold voltage in the generated voltage curves as the upper limit C-rate.

[0015] The control unit can be configured to acquire multiple battery curves, determine a standard battery curve corresponding to a standard C-rate and a reference battery curve corresponding to a reference C-rate among the acquired multiple battery curves, and set a threshold voltage based on the determined standard battery curve and the determined reference battery curve.

[0016] The control unit can be configured to select a reference capacity that meets predetermined conditions from a reference battery curve, and to set the voltage corresponding to the reference capacity in the standard battery curve as a threshold voltage.

[0017] The control unit can be configured to select the capacity corresponding to the point in the reference battery curve where the negative electrode voltage is 0 as the reference capacity.

[0018] The control unit can be configured to set the negative electrode voltage corresponding to the reference capacity in the standard battery curve as the threshold voltage.

[0019] According to another aspect of this disclosure, a battery pack may include a battery management device according to one aspect of this disclosure.

[0020] According to another aspect of the present disclosure, a battery management method manages battery cells that are charged multiple times at each of a plurality of C-rates. The battery management method may include the following steps: a plurality of battery curve acquisition step, which acquires a plurality of battery curves representing the correspondence between the voltage and capacity of the battery cell for each of the plurality of C-rates; a differential curve generation step, which generates a plurality of differential curves representing the correspondence between the voltage of the battery cell and the differential capacity for that voltage, based on each of the acquired plurality of battery curves; a differential curve classification step, which classifies the plurality of differential curves into a standard differential curve corresponding to a preset standard C-rate and a plurality of reference differential curves; a standard peak and reference peak determination step, which determines a standard peak in the standard differential curves and a reference peak in each of the plurality of reference differential curves; and an upper limit C-rate determination step, which compares the voltage of the determined standard peak with the voltage of the determined plurality of reference peaks and determines an upper limit C-rate for the battery cell based on the comparison result.

[0021] Technical effect

[0022] According to one aspect of the invention, since the charging and discharging of the battery cell can be controlled according to a determined upper limit C-rate, side reactions in the battery cell due to charging and discharging at a high C-rate can be prevented, and the battery cell lifespan can be increased because the degradation of the battery cell can be slowed down.

[0023] The effects of this disclosure are not limited to those described above, and other unmentioned effects can be clearly understood by those skilled in the art from the description of the claims. Attached Figure Description

[0024] The accompanying drawings illustrate a preferred embodiment of the present disclosure and, together with the foregoing disclosure, are intended to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure should not be construed as being limited to the drawings.

[0025] Figure 1 This is a schematic diagram illustrating a battery management device according to an embodiment of the present disclosure.

[0026] Figure 2 This is a schematic diagram illustrating a plurality of differential curves generated by a battery management device according to an embodiment of the present disclosure.

[0027] Figure 3 This is a schematic diagram illustrating a voltage curve generated by a battery management device according to an embodiment of the present disclosure.

[0028] Figure 4 This is a schematic diagram illustrating a plurality of battery curves according to embodiments of the present disclosure.

[0029] Figure 5 This is a diagram schematically illustrating an exemplary configuration of a battery pack according to another embodiment of the present disclosure.

[0030] Figure 6 The diagram schematically illustrates a battery management method according to yet another embodiment of the present disclosure. Detailed Implementation

[0031] 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 meanings and concepts corresponding to the technical solutions of this disclosure, on the basis of the principle that the inventors are allowed to define the terms appropriately for the best interpretation.

[0032] Therefore, the description presented herein is merely a preferred example for illustrative purposes only and is not intended to limit the scope of this disclosure. It should be understood that other equivalent substitutions and modifications may be made thereto without departing from the scope of this disclosure.

[0033] Furthermore, in describing this disclosure, detailed descriptions of relevant known elements or functions are omitted here where such descriptions would obscure the key subject matter of the disclosure.

[0034] Ordinal terms such as “first” and “second” can be used to distinguish one element from others among various elements, but are not intended to limit the element by means of the term.

[0035] Throughout this specification, when a section is referred to as “comprising” or “including” any element, unless otherwise expressly stated, it means that the section may further include other elements, without excluding other elements.

[0036] Furthermore, the term "control unit" described in the specification refers to a unit that processes at least one function or operation, and can be implemented by hardware, software, or a combination of hardware and software.

[0037] 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" when another element is placed between them.

[0038] In the following, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0039] Figure 1 This is a schematic diagram of a battery management device 100 according to an embodiment of the present disclosure.

[0040] According to embodiments of the present disclosure, the battery management device 100 can manage battery cells that are charged multiple times at each of a plurality of C-rates (current rates).

[0041] Here, a battery cell refers to a physically separable, independent unit comprising a negative terminal and a positive terminal. For example, a pouch-type lithium polymer cell can be considered a battery cell.

[0042] For example, the battery cell can be charged at a first C-rate C1, a second C-rate C2, a third C-rate C3, a fourth C-rate C4, and a fifth C-rate C5, respectively. In other words, the battery cell can be fully charged at five C-rates from 0% to 100% of its SOC (State of Charge).

[0043] As a specific example, the first C-rate C1 can be 0.05C, the second C-rate C2 can be 0.33C, the third C-rate C3 can be 0.5C, the fourth C-rate C4 can be 0.7C, and the fifth C-rate C5 can be 1C.

[0044] Reference Figure 1 The battery management device 100 according to the embodiments of the present disclosure may include a curve generation unit 110 and a control unit 120.

[0045] The curve generation unit 110 can be configured to obtain multiple battery curves representing the correspondence between the voltage and capacity of the battery cell at each of multiple C-rates.

[0046] A battery curve can be a curve that represents the relationship between the voltage and capacity of a battery cell. For example, when the voltage is set to X and the capacity is set to Y, the battery curve can be represented as an XY graph or an XY table.

[0047] For example, as in the aforementioned embodiment, when the battery cell is charged at a first C-rate C1, a second C-rate C2, a third C-rate C3, a fourth C-rate C4, and a fifth C-rate C5, the curve generation unit 110 can obtain five battery curves corresponding to each of the first C-rate C1, the second C-rate C2, the third C-rate C3, the fourth C-rate C4, and the fifth C-rate C5.

[0048] The curve generation unit 110 can be configured to generate multiple differential curves representing the correspondence between the voltage of a battery cell and the differential capacity of that voltage, based on each of the multiple battery curves obtained.

[0049] The differential curve can be a curve representing the relationship between the voltage and differential capacity of a battery cell. First, for each of the multiple battery curves, the curve generation unit 110 can calculate the differential capacity by differentiating the capacity based on the voltage. Furthermore, the curve generation unit 110 can generate a differential curve based on the relationship between voltage and differential capacity. That is, when the voltage is set to X and the differential capacity is set to Y, the differential curve can be represented as an XY graph or an XY table.

[0050] Figure 2 This is a schematic diagram of a plurality of differential curves generated by a battery management device 100 according to an embodiment of the present disclosure.

[0051] For example, refer to Figure 2 The curve generation unit 110 can generate five differential curves P1, P2, P3, P4, and P5 based on five battery curves. The first differential curve P1 corresponds to the battery cell charged at a first C-rate C1. The second differential curve P2 corresponds to the battery cell charged at a second C-rate C2. The third differential curve P3 corresponds to the battery cell charged at a third C-rate C3. The fourth differential curve P4 corresponds to the battery cell charged at a fourth C-rate C4. The fifth differential curve P5 corresponds to the battery cell charged at a fifth C-rate C5.

[0052] The control unit 120 can be configured to obtain multiple differential curves P1, P2, P3, P4, and P5 from the curve generation unit 110.

[0053] For example, control unit 120 can be connected to communicate with curve generation unit 110. Curve generation unit 110 can send multiple generated differential curves P1, P2, P3, P4, P5 to control unit 120, and control unit 120 can obtain multiple differential curves P1, P2, P3, P4, P5 by receiving multiple differential curves P1, P2, P3, P4, P5 from curve generation unit 110.

[0054] The control unit 120 can be configured to classify multiple differential curves P1, P2, P3, P4, P5 into standard differential curves corresponding to a preset standard C-rate and multiple reference differential curves.

[0055] For example, the standard C-rate can be preset to be less than 0.1C. In this case, the control unit 120 can set the differential curve corresponding to the C-rate less than 0.1C among the multiple differential curves P1, P2, P3, P4, and P5 as the standard differential curve, and set the remaining differential curves as reference differential curves.

[0056] If multiple differential curves correspond to a standard C-rate, the control unit 120 can set the differential curve with the smallest corresponding C-rate as the standard differential curve and set the remaining differential curves as reference differential curves.

[0057] Preferably, the standard C-rate can be preset to 0.05C. In this case, the control unit 120 can set the differential curve corresponding to 0.05C among the multiple differential curves as the standard differential curve, and set the remaining differential curves as reference differential curves.

[0058] Meanwhile, if there is no differential curve corresponding to the standard C-rate among the multiple differential curves P1, P2, P3, P4, P5, the control unit 120 can set the differential curve with the smallest C-rate among the multiple differential curves as the standard differential curve and set the remaining differential curves as reference differential curves.

[0059] For example, assuming the standard C-rate is preset to 0.05C, the first C-rate C1, second C-rate C2, third C-rate C3, fourth C-rate C4, and fifth C-rate C5 are 0.05C, 0.33C, 0.5C, 0.7C, and 1C, respectively. Figure 2In this implementation, the control unit 120 can set the first differential curve P1 corresponding to the first C-rate C1 as the standard differential curve, and set the second to fifth differential curves P2, P3, P4, and P5 corresponding to the second to fifth C-rates C2, C3, C4, and C5 as reference differential curves. That is, among the first to fifth differential curves P1, P2, P3, P4, and P5, the first differential curve P1 can be classified as the standard differential curve, and the second to fifth differential curves P2, P3, P4, and P5 can be classified as reference differential curves.

[0060] The control unit 120 can be configured to determine a standard peak value in a standard differential curve and a reference peak value in each of a plurality of reference differential curves.

[0061] The standard peak value and the reference peak value can be corresponding peak values. That is, the standard peak value and the reference peak value can be points with an upward bulge in a predetermined voltage range in the corresponding differential curve. Here, a point with an upward bulge is a point where the instantaneous rate of change of the differential capacitance with respect to voltage is 0, and based on this point, the instantaneous rate of change on the low potential side is positive, while the instantaneous rate of change on the high potential side is negative.

[0062] For example, the standard peak and reference peak can be the points with the largest differential capacity among the peaks contained in the range of 3.6V to 3.8V in the corresponding differential curve.

[0063] exist Figure 2 In this implementation, the first differential curve P1 may include a first peak value Pa, the second differential curve P2 may include a second peak value Pb, and the third differential curve P3 may include a third peak value Pc. The fourth differential curve P4 may include a fourth peak value Pd, and the fifth differential curve P5 may include a fifth peak value Pe. That is, the control unit 120 can determine the standard peak value in the standard differential curve and determine the reference peak value in each of the plurality of reference differential curves.

[0064] The control unit 120 can be configured to compare the voltage of a determined standard peak with the voltage of a plurality of determined reference peaks.

[0065] Specifically, the control unit 120 can compare the voltage of a standard peak value with the voltage of a plurality of determined reference peak values. In other words, the control unit 120 can calculate the voltage difference between the standard peak value and each of the plurality of reference peak values.

[0066] For example, in Figure 2In this implementation, the voltage of the first peak Pa, which serves as the standard peak value, can be Va. The voltages of the second peak Pb, third peak Pc, fourth peak Pd, and fifth peak Pe, corresponding to multiple reference peak values, can be Vb, Vc, Vd, and Ve, respectively. The control unit 120 can calculate a first voltage difference between the voltage Va of the first peak Pa and the voltage Vb of the second peak Pb, and calculate a second voltage difference between the voltage Va of the first peak Pa and the voltage Vc of the third peak Pc. The control unit 120 can calculate a third voltage difference between the voltage Va of the first peak Pa and the voltage Vd of the fourth peak Pd, and calculate a fourth voltage difference between the voltage Va of the first peak Pa and the voltage Ve of the fifth peak Pe.

[0067] The control unit 120 can be configured to determine the upper limit C-rate of the battery cell based on the comparison results. Specifically, the control unit 120 can be configured to compare a plurality of calculated voltage differences with a preset threshold voltage Vth, and determine the upper limit C-rate based on the comparison results.

[0068] For example, in the aforementioned embodiment, the control unit 120 can compare each of the calculated first to fourth voltage differences with a preset threshold voltage Vth. Preferably, the control unit 120 can compare each of the first to fourth voltage differences with the threshold voltage Vth and determine the upper limit C-rate of the battery cell based on the comparison result.

[0069] Here, the upper limit C-rate is set for each battery cell and can refer to the maximum C-rate that the battery cell is allowed to charge and discharge. That is, the upper limit C-rate determined by the control unit 120 can be set as the maximum C-rate that the battery cell is allowed to discharge. In addition, the battery cell can be charged or discharged at a C-rate that is lower than the determined upper limit C-rate.

[0070] For example, when the battery cell is charged beyond a determined upper limit C-rate, side reactions may occur within the battery cell. Specifically, lithium plating, in which lithium is deposited on the negative electrode of the battery cell, may occur. Therefore, the control unit 120 can prevent side reactions from occurring in the battery cell during charging and discharging by determining the upper limit C-rate of the battery cell based on a comparison of the voltage of a standard peak with the voltages of a plurality of determined reference peaks.

[0071] In other words, since the charging and discharging of the battery cell can be controlled according to the upper limit C-rate determined by the battery management device 100 according to the embodiments of the present disclosure, the battery cell can degrade slowly to increase the battery life.

[0072] Meanwhile, the control unit 120 disposed 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 implement the various control logics executed in this disclosure. Furthermore, when the control logic is implemented in software, the control unit 120 can be implemented as a set of program modules. In this case, the program modules can be stored in memory and executed by the control unit 120. The memory can be located internally or externally to the control unit 120 and can be connected to the control unit 120 by various known means.

[0073] In addition, the battery management device 100 may also include a storage unit 130. The storage unit 130 may store data required for the operation and function of each component 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 130, as long as it is a 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 130 may store program code that defines the processes executable by the control unit 120.

[0074] For example, multiple battery curves can be stored in the storage unit 130. Additionally, the curve generation unit 110 can access the storage unit 130 to obtain multiple battery curves. Furthermore, multiple differential curves generated by the curve generation unit 110 can be stored in the storage unit 130. The control unit 120 can not only directly receive multiple differential curves from the curve generation unit 110, but also access the storage unit 130 to obtain both multiple battery curves and multiple differential curves.

[0075] The following describes an implementation of how the control unit 120 determines the upper limit C-rate.

[0076] For example, the control unit 120 can determine any one of a plurality of C-rates at which the battery cell is charged as the upper limit C-rate.

[0077] The control unit 120 can be configured to determine the target peak value TP as a reference peak value where the calculated voltage difference is equal to or greater than the threshold voltage Vth.

[0078] For example, in Figure 2 In this implementation, a threshold voltage Vth can be preset. Furthermore, a reference peak whose voltage difference from the standard peak voltage is equal to or greater than the threshold voltage Vth can be a fifth peak Pe. That is, the voltage difference between the fifth peak Pe and the standard peak voltage can be greater than the threshold voltage Vth. Therefore, the control unit 120 can determine the fifth peak Pe as the target peak TP.

[0079] If there are multiple reference peaks with calculated voltage differences equal to or greater than the threshold voltage Vth, the control unit 120 can determine the reference peak with the smallest calculated voltage difference equal to or greater than the threshold voltage Vth as the target peak TP. In other words, the control unit 120 can determine the reference peak with the smallest calculated voltage difference equal to or greater than the threshold voltage Vth as the target peak TP.

[0080] The control unit 120 can be configured to determine the upper limit C-rate as the C-rate corresponding to the reference differential curve including the determined target peak TP.

[0081] For example, in Figure 2 In this implementation, when the fifth peak Pe is determined to be the target peak TP, the control unit 120 can select a fifth differential curve P5 that includes the target peak TP. Additionally, the control unit 120 can determine the fifth C-rate C5 corresponding to the fifth differential curve P5 as the upper limit C-rate.

[0082] As another example, the control unit 120 may determine a target C-rate TC based on multiple C-rates at which the battery cell is charged, and set the determined target C-rate TC as the upper limit C-rate.

[0083] Specifically, the control unit 120 can be configured to generate voltage curves Pv that represent the correspondence between multiple voltage differences and multiple C-rates.

[0084] For example, the control unit 120 can generate a voltage curve Pv based on the C-rate and voltage difference of the first differential curve P1, the second differential curve P2, the third differential curve P3, the fourth differential curve P4, and the fifth differential curve P5.

[0085] Figure 3 This is a schematic diagram of a voltage curve Pv generated by a battery management device 100 according to an embodiment of the present disclosure.

[0086] Reference Figure 3 The control unit 120 can generate voltage curves Pv representing the first C-rate C1, the second C-rate C2 and the first voltage difference, the third C-rate C3 and the second voltage difference, the fourth C-rate C4 and the third voltage difference, and the fifth C-rate C5 and the fourth voltage difference. Here, the first C-rate C1 is the C-rate corresponding to the standard differential curve. That is, since the voltage difference is calculated based on the standard peak voltage, the voltage difference corresponding to the first C-rate C1 can be set to 0.

[0087] In addition, refer to Figure 2The first voltage difference can be Vb-Va, and the second voltage difference can be Vc-Va. Furthermore, the third voltage difference can be Vd-Va, and the fourth voltage difference can be Ve-Va.

[0088] The control unit 120 can be configured to determine the target C-rate TC corresponding to the threshold voltage Vth in the generated voltage curve Pv as the upper limit C-rate.

[0089] Specifically, the control unit 120 can select a target C-rate TC corresponding to the threshold voltage Vth by placing the threshold voltage Vth into the generated voltage curve Pv. Furthermore, the control unit 120 can determine the selected target C-rate TC as the upper limit C-rate.

[0090] For example, in Figure 3 In this implementation, the target C-rate corresponding to the threshold voltage Vth can be TC within the range of 0.8C to 1C. The control unit 120 can determine the target C-rate TC as the upper limit C-rate of the battery cell.

[0091] The following describes how the threshold voltage Vth is set by the control unit 120.

[0092] The control unit 120 can be configured to obtain multiple battery curves.

[0093] For example, the control unit 120 can access the storage unit 130 to obtain multiple battery profiles.

[0094] Figure 4 This is a schematic diagram illustrating a plurality of battery curves according to embodiments of the present disclosure.

[0095] Specifically Figure 4 It can be a negative electrode curve representing the relationship between the voltage and capacity of the negative electrode of a battery cell that is charged multiple times at each of a plurality of C-rates.

[0096] Preferably, the battery curves include a positive electrode curve representing the relationship between voltage and capacity at the positive electrode of the battery cell, a negative electrode curve representing the relationship between voltage and capacity at the negative electrode of the battery cell, and a full-cell curve representing the relationship between voltage and capacity of the entire battery cell. For example, the curve generation unit 110 can generate a differential curve based on the full-cell curves. Additionally, the control unit 120 can obtain the negative electrode curve from the battery curves from the storage unit 130.

[0097] For example, in Figure 4In this embodiment, the control unit 120 can obtain a first negative electrode curve NP1 corresponding to the first C-rate C1, a second negative electrode curve NP2 corresponding to the second C-rate C2, and a third negative electrode curve NP3 corresponding to the third C-rate C3. Furthermore, the control unit 120 can obtain a fourth negative electrode curve NP4 corresponding to the fourth C-rate C4 and a fifth negative electrode curve NP5 corresponding to the fifth C-rate C5.

[0098] The control unit 120 can be configured to determine, among the multiple battery curves obtained, a standard battery curve corresponding to a standard C-rate and a reference battery curve corresponding to a reference C-rate.

[0099] Specifically, the control unit 120 can be configured to determine a standard battery curve and a reference battery curve among the multiple negative electrode curves obtained.

[0100] For example, the reference C-rate can be preset to 1C or higher. In this case, the control unit 120 can set the battery curve corresponding to a C-rate of 1C or higher among multiple battery curves as the reference battery curve. If multiple battery curves correspond to the reference C-rate, the control unit 120 can set the battery curve with the highest corresponding C-rate as the standard battery curve and set the remaining battery curves as reference battery curves.

[0101] Preferably, the reference C-rate can be preset to 1C. In this case, the control unit 120 can set the battery curve corresponding to 1C among multiple battery curves as the reference battery curve.

[0102] Furthermore, when there is no battery curve among the multiple battery curves that corresponds to the reference C-rate, the control unit 120 can set the battery curve with the largest C-rate among the multiple battery curves as the reference battery curve.

[0103] For example, in Figure 4 In this implementation, it is assumed that the standard C-rate is preset to 0.05C, and the reference C-rate is preset to 1C. Furthermore, it is assumed that the first C-rate C1, second C-rate C2, third C-rate C3, fourth C-rate C4, and fifth C-rate C5 are 0.05C, 0.33C, 0.5C, 0.7C, and 1C, respectively. The control unit 120 can determine the first negative electrode curve NP1 corresponding to the first C-rate C1 as the standard battery curve, and determine the fifth negative electrode curve NP5 corresponding to the fifth C-rate C5 as the reference battery curve.

[0104] The control unit 120 can be configured to set the threshold voltage Vth based on a determined standard battery curve and a determined reference battery curve.

[0105] Specifically, the control unit 120 can select a reference capacity that meets predetermined conditions from a reference battery curve. Additionally, the control unit 120 can be configured to set the voltage corresponding to the reference capacity in the standard battery curve as a threshold voltage Vth.

[0106] For example, in Figure 4 In this implementation, it is assumed that the reference capacity that meets the predetermined conditions is Qr. The control unit 120 can set the voltage corresponding to the reference capacity in the standard battery curve as the threshold voltage Vth. That is, the voltage corresponding to the reference capacity (Qr) in the first negative electrode curve NP1 can be set as the threshold voltage Vth.

[0107] Specifically, the control unit 120 can be configured to select the capacity corresponding to the point where the negative electrode voltage is 0 in the reference battery curve as the reference capacity. That is, the reference capacity that meets the predetermined conditions can be the capacity corresponding to 0 [V] in the reference battery curve. In addition, the control unit 120 can be configured to set the negative electrode voltage corresponding to the reference capacity in the standard battery curve as the threshold voltage Vth.

[0108] For example, in Figure 4 In this implementation, the capacity corresponding to 0 [V] in the fifth negative electrode curve NP5 can be Qr. Therefore, the control unit 120 can select Qr [mAh] as the reference capacity. Additionally, the voltage corresponding to the reference capacity in the first negative electrode curve NP1 can be Vth. Therefore, the control unit 120 can set Vth [V] as the threshold voltage Vth.

[0109] The battery management device 100 according to this disclosure can be applied to a BMS (Battery Management System). That is, a BMS according to this disclosure may include the aforementioned battery management device 100. In this configuration, at least some of the components of the battery management device 100 can be implemented by supplementing or adding functions included in a conventional BMS configuration. For example, the curve generation unit 110, control unit 120, and storage unit 130 of the battery management device 100 can be implemented as components of a BMS.

[0110] Furthermore, the battery management device 100 according to this disclosure can be disposed in the battery pack 1. That is, the battery pack 1 according to this disclosure may include the aforementioned battery management device 100 and one or more battery cells. In addition, the battery pack 1 may also include electrical equipment (relays, fuses, etc.) and a housing.

[0111] Figure 5 This is a diagram schematically illustrating an exemplary configuration of a battery pack 1 according to another embodiment of the present disclosure.

[0112] Reference Figure 5The battery pack 1 may include a battery management device 100, a measurement unit 200, and a charging and discharging unit 300.

[0113] exist Figure 5 In this embodiment, the measurement unit can be connected to a first sensing line SL1, a second sensing line SL2, and a third sensing line SL3. The measurement unit can measure the positive electrode voltage of the battery cell through the first sensing line SL1 and the negative electrode voltage of the battery cell through the second sensing line SL2. Additionally, the measurement unit can measure the voltage of the battery cell by calculating the difference between the measured positive electrode voltage and the measured negative electrode voltage.

[0114] Additionally, the measurement unit can be connected to the current measurement unit A via the third sensing line SL3. The current measurement unit A can be positioned on the charging and discharging path of the battery cell. For example, the current measurement unit A can be an ammeter or a shunt resistor.

[0115] Furthermore, the charging and discharging paths can be high-current paths through which the charging and discharging currents of the battery cell flow. Therefore, the measurement unit can measure the current of the battery cell B through the third sensing line SL3 connected to the current measurement unit A, and measure the capacity of the battery cell based on the measured current.

[0116] Furthermore, both ends of the charging and discharging unit 300 can be connected to the charging and discharging paths of the battery cell. For example, one end of the charging and discharging unit 300 can be connected to the positive terminal of the battery cell in the charging and discharging path. The other end of the charging and discharging unit 300 can be connected to the negative terminal of the battery cell in the charging and discharging path. Additionally, the charging and discharging unit 300 can charge and / or discharge the battery cell under the control of the control unit 120.

[0117] For example, in Figure 5 In this implementation, the charging and discharging unit 300 can charge the battery cell multiple times at each of a plurality of C-rates. Specifically, the charging and discharging unit 300 can charge the battery cell from 0% SOC (State of Charge) to 100%. The measurement unit can measure the voltage and capacity of the battery cell while it is being charged and generate a battery curve representing the correspondence between the voltage and capacity of the battery cell. The measurement unit can send the generated multiple battery curves to the battery management device 100, and the curve generation unit 110 can receive the multiple battery curves from the measurement unit.

[0118] Figure 6 The diagram schematically illustrates a battery management method according to yet another embodiment of the present disclosure.

[0119] Preferably, the battery management method is a method for managing battery cells that are charged multiple times at each of a plurality of C-rates, and each step of the battery management method can be performed by the battery management device 100. In the following description, for ease of description, content overlapping with the previously described content will be omitted or briefly described.

[0120] Reference Figure 6 The battery management method may include multiple battery curve acquisition steps (S100), differential curve generation steps (S200), differential curve classification steps (S300), standard peak and reference peak determination steps (S400), and upper limit C-rate determination steps (S500).

[0121] The multiple battery curve acquisition step (S100) is a step of obtaining multiple battery curves that represent the correspondence between the voltage and capacity of the battery cells at each of the multiple C-rates, and can be performed by the curve generation unit 110.

[0122] Each battery curve can represent the correspondence between the voltage and capacity of a battery cell charged at a corresponding C-rate. The curve generation unit 110 can receive multiple battery curves from an external source, or it can access the storage unit 130 to obtain multiple battery curves.

[0123] For example, the curve generation unit 110 can obtain the first battery curve to the fifth battery curve, and each of the first battery curve to the fifth battery curve can correspond to each of the first C-rate to the fifth C-rate C1, C2, C3, C4, C5.

[0124] The differential curve generation step (S200) is a step of generating multiple differential curves based on each of the multiple battery curves obtained, representing the correspondence between the voltage of the battery cell and the differential capacity of that voltage, and can be performed by the curve generation unit 110.

[0125] For example, the curve generation unit 110 can generate multiple differential curves based on each of the multiple battery curves obtained. That is, the curve generation unit 110 can generate one differential curve for each battery curve.

[0126] exist Figure 2 In this embodiment, the curve generation unit 110 can generate a first differential curve P1 based on a first battery curve, and a second differential curve P2 based on a second battery curve. The curve generation unit 110 can also generate a third differential curve P3 based on a third battery curve, a fourth differential curve P4 based on a fourth battery curve, and a fifth differential curve P5 based on a fifth battery curve.

[0127] The differential curve classification step (S300) is a step of classifying multiple differential curves into a standard differential curve corresponding to a preset standard C-rate and multiple reference differential curves, and can be executed by the control unit 120.

[0128] For example, the standard C-rate can be set to 0.05°C, the first C-rate C1 can be 0.05°C, the second C-rate C2 can be 0.33°C, and the third C-rate C3 can be 0.5°C. Assume the fourth C-rate C4 is 0.7°C and the fifth C-rate C5 is 1°C. Figure 2 In one implementation, the control unit 120 can classify the first differential curve P1 corresponding to the standard C-rate as a standard differential curve, and classify the second to fifth differential curves P2, P3, P4, and P5 as reference differential curves.

[0129] The standard peak and reference peak determination step (S400) is a step of determining the standard peak in the standard differential curve and the reference peak in each of the plurality of reference differential curves, and can be executed by the control unit 120.

[0130] For example, the control unit 120 can determine the first to fifth peak values ​​Pa, Pb, Pc, Pd, and Pe in each of the first to fifth differential curves P1, P2, P3, P4, and P5. Additionally, the first peak value Pa included in the first differential curve P1, which serves as a standard differential curve, can be determined as the standard peak value. Furthermore, the second to fifth peak values ​​Pb, Pc, Pd, and Pe included in the second to fifth differential curves P2, P3, P4, and P5, which serve as reference differential curves, can be determined as reference peak values.

[0131] The upper limit C-rate determination step (S500) is a step of comparing the voltage of the determined standard peak with the voltage of a plurality of determined reference peaks and determining the upper limit C-rate of the battery cell based on the comparison result, which can be executed by the control unit 120.

[0132] For example, in Figure 2 In one implementation, the control unit 120 can calculate the voltage difference by comparing the voltage of a standard peak and the voltage of multiple reference peaks, compare the calculated voltage difference with the threshold voltage Vth, and determine the upper limit C-rate of the battery cell based on the comparison result.

[0133] The battery management method according to embodiments of this disclosure can control the charging and discharging of a battery cell by determining an upper limit C-rate at which the degradation of the battery cell can be accelerated (i.e., further side reactions can occur in the battery cell) for a battery cell that is charged multiple times at each of a plurality of C-rates. Therefore, since the battery cell can be charged and discharged at a C-rate lower than the upper limit C-rate, the lifespan of the battery cell can be increased.

[0134] The embodiments of this disclosure described above can be implemented not only by devices and methods, but also by a program that implements functions corresponding to the configuration of the embodiments of this disclosure, or a recording medium on which the program is recorded. Those skilled in the art can readily implement the program or recording medium from the above description of the embodiments.

[0135] 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 example only, as various variations and modifications within the scope of this disclosure will become apparent to those skilled in the art from the detailed description.

[0136] Furthermore, those skilled in the art can make many substitutions, modifications and variations to the above-described disclosure without departing from the technical aspects of this disclosure, and this disclosure is not limited to the above-described embodiments and accompanying drawings, and each embodiment can be selectively combined in part or in whole to allow for various modifications.

[0137] (See attached image labels)

[0138] 1: Battery pack

[0139] 100: Battery Management Device

[0140] 110: Curve generation unit

[0141] 120: Control Unit

[0142] 130: Storage unit

[0143] 200: Measurement Unit

[0144] 300: Charging and discharging unit

Claims

1. A battery management device that manages battery cells that are charged multiple times at each of a plurality of C-rates, the battery management device comprising: A curve generation unit is configured to obtain a plurality of battery curves representing the correspondence between the voltage and capacity of the battery cell for each of the plurality of C-rates, and to generate a plurality of differential curves representing the correspondence between the voltage of the battery cell and the differential capacity for that voltage based on each of the plurality of battery curves obtained. as well as A control unit is configured to obtain the plurality of differential curves from the curve generation unit, classify the plurality of differential curves into a plurality of reference differential curves and a standard differential curve corresponding to a preset standard C-rate, determine a standard peak value in the standard differential curves, determine a reference peak value in each of the plurality of reference differential curves, compare the voltage of the determined standard peak value with the voltage of the determined plurality of reference peak values ​​respectively, and determine the upper limit C-rate of the battery cell based on the comparison results. The control unit is configured to calculate the voltage difference between the determined standard peak value and each of the determined plurality of reference peak values, compare the calculated plurality of voltage differences with a preset threshold voltage, and determine the upper limit C-rate based on the comparison result.

2. The battery management device according to claim 1, in, The control unit is configured to determine a reference peak value where the calculated voltage difference is equal to or greater than the threshold voltage as the target peak value, and to determine the C-rate corresponding to the reference differential curve including the determined target peak value as the upper limit C-rate.

3. The battery management device according to claim 1, in, The control unit is configured to generate voltage curves representing the correspondence between the plurality of voltage differences and the plurality of C-rates, and to determine the target C-rate corresponding to the threshold voltage in the generated voltage curves as the upper limit C-rate.

4. The battery management device according to claim 1, wherein, The control unit is configured to obtain the plurality of battery curves, determine a standard battery curve corresponding to the standard C-rate and a reference battery curve corresponding to the reference C-rate among the obtained plurality of battery curves, and set the threshold voltage based on the determined standard battery curve and the determined reference battery curve.

5. The battery management device according to claim 4, in, The control unit is configured to select a reference capacity that meets predetermined conditions from the reference battery curve, and to set the voltage corresponding to the reference capacity in the standard battery curve as the threshold voltage.

6. The battery management device according to claim 5, in, The control unit is configured to select the capacity corresponding to the point in the reference battery curve where the negative electrode voltage is 0 as the reference capacity.

7. The battery management device according to claim 5, in, The control unit is configured to set the negative electrode voltage corresponding to the reference capacity in the standard battery curve as the threshold voltage.

8. The battery management device according to claim 1, further comprising a storage unit, the storage unit storing data required for the operation and function of each component of the battery management device, and data generated during the execution of the operation or function.

9. The battery management device according to claim 1, wherein, The standard peak value and the reference peak value are points in the differential curve corresponding to the standard peak value and the reference peak value that have an upward convex shape within a predetermined voltage range, and the point with the upward convex shape refers to the point where the instantaneous rate of change of the differential capacitance with respect to the voltage is 0.

10. A battery pack comprising a battery management device according to any one of claims 1 to 9.

11. A battery management method for managing a battery cell that is charged multiple times at each of a plurality of C-rates, the battery management method comprising the steps of: Multiple battery curve acquisition steps, which acquire multiple battery curves representing the correspondence between the voltage and capacity of the battery cell for each of the multiple C-rates; A differential curve generation step, which generates multiple differential curves representing the correspondence between the voltage of the battery cell and the differential capacity for that voltage, based on each of the multiple battery curves obtained. The differential curve classification step classifies the plurality of differential curves into a plurality of reference differential curves and a standard differential curve corresponding to a preset standard C-rate; The standard peak value and reference peak value determination step determines the standard peak value in the standard differential curve and determines the reference peak value in each of the plurality of reference differential curves; as well as The upper limit C-rate determination step compares the voltage of a determined standard peak value with the voltage of a plurality of determined reference peak values, and determines the upper limit C-rate of the battery cell based on the comparison results. The step of determining the upper limit C-rate includes the following steps: Calculate the voltage difference between the determined standard peak value and each of the determined plurality of reference peak values; and The calculated voltage differences are compared with a preset threshold voltage, and the upper limit C-rate is determined based on the comparison results.

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