Battery management device and method, battery pack comprising a battery management device

Abstract

A battery management device according to one embodiment of the present application includes a turning point extraction unit for extracting a turning point from a battery curve representing a change in voltage of a battery over time, and a control unit for determining a target voltage, a target temperature, and a target current amount of the battery corresponding to the turning point, determining a reference voltage in a preset voltage table corresponding to the target temperature and the target current amount, and diagnosing whether lithium deposition occurs in the battery based on the reference voltage and the target voltage.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2022-0016361, filed in Korea on February 8, 2022, the disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure relates to battery management devices and methods, and more specifically, to battery management devices and methods capable of diagnosing whether lithium deposition has occurred in a battery. 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 seen significant development. 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 are particularly noteworthy because they exhibit almost no memory effect compared to nickel-based batteries, and also have extremely low self-charging rates and high energy density.

[0005] Extensive research is underway on these batteries in terms of high capacity and high density, but improving lifespan and safety is also crucial. This requires suppressing decomposition reactions with the electrolyte on the electrode surface and preventing overcharging and over-discharging.

[0006] Specifically, it is necessary to prevent lithium deposition (lithium plating, lithium Li) on the negative electrode surface. When lithium deposition occurs on the negative electrode surface, it leads to side reactions with the electrolyte and alters the battery's kinetic balance, resulting in battery degradation. Furthermore, because lithium metal deposition on the negative electrode surface can cause internal short circuits, there is a risk of fire and explosion due to these internal short circuits.

[0007] Traditionally, lithium deposition is diagnosed based on the change in voltage over time during the idle period after charging. However, this method is suitable for situations where a large amount of lithium deposition occurs during the corresponding idle period, and the problem is that it cannot accurately diagnose whether lithium deposition has occurred when lithium deposition accumulates little by little.

[0008] Therefore, there is a need to develop a technology that can accurately diagnose lithium deposition even as it gradually accumulates. Summary of the Invention

[0009] Technical issues

[0010] This disclosure is designed to solve problems in related technologies, and therefore relates to providing a battery management device and method for diagnosing whether lithium deposition has occurred in a battery based on the voltage at which an inflection point is generated in a battery curve in which the indicated voltage changes over time.

[0011] These and other objects and advantages of this disclosure will become clear from the following detailed description and from the 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.

[0012] Technical solution

[0013] According to one aspect of this disclosure, a battery management device may include: an inflection point extraction unit configured to extract an inflection point from a battery curve representing the change of battery voltage over time; and a control unit configured to determine a target voltage, a target temperature, and a target current of the battery corresponding to the inflection point, determine a reference voltage in a preset voltage meter corresponding to the target temperature and the target current, and diagnose whether lithium deposition has occurred in the battery based on the reference voltage and the target voltage.

[0014] The control unit can be configured to diagnose whether lithium deposition has occurred based on the voltage deviation between the reference voltage and the target voltage.

[0015] The control unit can be configured to diagnose lithium deposition in the battery when the voltage deviation is equal to or greater than a preset threshold voltage.

[0016] The control unit can be configured to diagnose the absence of lithium deposition in the battery when the voltage deviation is less than a threshold voltage.

[0017] The control unit can be configured to determine a reference temperature corresponding to the target temperature, a reference current corresponding to the target current, and a reference voltage in the voltmeter corresponding to the reference temperature and the reference current.

[0018] The control unit can be configured to determine the temperature closest to the target temperature among a plurality of predetermined temperatures as the reference temperature, and the current closest to the target current among a plurality of predetermined current quantities as the reference current quantity.

[0019] The control unit can be configured to determine at least one reference temperature from a plurality of predetermined temperatures that falls within a predetermined temperature range from the target temperature, to determine at least one reference current from a plurality of predetermined currents that falls within a predetermined current range from the target current, and to determine the minimum voltage from at least one voltage based on a combination of the determined at least one reference temperature and the determined at least one reference current as the reference voltage.

[0020] The control unit can be configured to determine a reference voltage in the voltmeter corresponding to the target temperature and target current by using an interpolation method when multiple predetermined temperatures do not have the same value as the target temperature or multiple predetermined currents do not have the same value as the target current.

[0021] A voltmeter is a meter that records the voltage of a battery based on its temperature and the amount of current it receives.

[0022] A battery curve can be recorded as a curve representing the voltage over a constant current charging or discharging time.

[0023] According to another aspect of this disclosure, the battery management device may also include a storage unit configured to store a voltmeter.

[0024] The control unit can be configured to pre-store a reference voltage corresponding to the target temperature and target current in a voltage table stored in the storage unit, and to update the reference voltage to the target voltage when the target voltage is less than the reference voltage.

[0025] According to another aspect of this disclosure, a battery pack may include a battery management device according to one aspect of this disclosure.

[0026] A battery management server according to another aspect of this disclosure may include a battery management device according to one aspect of this disclosure.

[0027] According to another aspect of the present disclosure, the battery management method may include the following steps: an inflection point extraction step, which extracts an inflection point from a battery curve representing the change of battery voltage over time; a target information determination step, which determines a target voltage, a target temperature, and a target current of the battery corresponding to the inflection point; a reference voltage determination step, which determines a reference voltage in a preset voltage table corresponding to the target temperature and the target current; and a lithium deposition diagnosis step, which diagnoses whether lithium deposition has occurred in the battery based on the reference voltage and the target voltage.

[0028] Technical effect

[0029] According to one aspect of this disclosure, it is possible to accurately diagnose whether lithium deposition has occurred in a battery. Specifically, even when lithium metal deposition is slow, it is possible to diagnose whether lithium metal deposition has occurred.

[0030] In addition, according to one aspect of this disclosure, it is possible to quickly diagnose whether lithium deposition has occurred based on measurement data during the charging and discharging process of the battery.

[0031] The effects of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the description of the claims other effects not mentioned. Attached Figure Description

[0032] 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 should not be construed as being limited to the drawings.

[0033] Figure 1 This is a schematic diagram illustrating a battery management device according to an embodiment of the present disclosure.

[0034] Figure 2 This is a schematic diagram illustrating the battery curves according to embodiments of the present disclosure.

[0035] Figure 3 This is a diagram schematically illustrating the voltage behavior of a standard battery and a first battery according to embodiments of the present disclosure.

[0036] Figure 4 This is a diagram schematically illustrating the voltage behavior of a standard battery and a second battery according to embodiments of the present disclosure.

[0037] Figure 5 This is a diagram schematically illustrating a voltmeter according to an embodiment of the present disclosure.

[0038] Figure 6 It is a schematic diagram showing the positive and negative electrode potential curves of a normal battery.

[0039] Figure 7 It is a schematic diagram showing the positive and negative electrode potential curves of a lithium deposition battery.

[0040] Figure 8 This is a diagram schematically illustrating an exemplary construction of a battery pack according to another embodiment of the present disclosure.

[0041] Figure 9 This is a schematic diagram illustrating a battery management method according to yet another embodiment of the present disclosure. Detailed Implementation

[0042] It should be understood that the terms used in the specification and appended claims should not be construed as limited to their general or dictionary meanings, but rather as being interpreted based on their meanings and concepts corresponding to the technical aspects of this disclosure, on the basis of the principle that the inventors are allowed to define the terms appropriately for the best interpretation.

[0043] 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.

[0044] Furthermore, in describing this disclosure, detailed descriptions are omitted where such descriptions would obscure the key subject matter of the disclosure.

[0045] Terms including ordinal numbers such as “first” and “second” can be used to distinguish one element from another among various elements, but are not intended to limit the elements by means of the term.

[0046] Throughout this specification, when a section is referred to as “comprising” or “including” any element, it means that, unless otherwise expressly stated, that section may also include other elements, without excluding other elements.

[0047] Furthermore, throughout the specification, when a 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" with another element placed between them.

[0048] In the following, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0049] Figure 1 This is a schematic diagram illustrating a battery management device 100 according to an embodiment of the present disclosure.

[0050] Specifically, the battery management device 100 can diagnose whether lithium metal deposition has occurred in the battery. Here, a battery refers to a physically separable, independent unit comprising a negative terminal and a positive terminal. For example, a lithium-ion battery or a lithium polymer battery can be considered a battery.

[0051] Reference Figure 1 The battery management device 100 may include an inflection point extraction unit 110 and a control unit 120.

[0052] The inflection point extraction unit 110 can be configured to extract inflection points from the battery curve BP, which represents the change of battery voltage over time.

[0053] Here, the battery curve BP is generated during the charging or discharging of the battery and can be a curve representing the change of the battery voltage over time. Preferably, the battery curve BP can be a curve recorded as representing the voltage according to the charging or discharging time when the battery is charged or discharged with a constant current.

[0054] Figure 2This is a schematic diagram illustrating the battery curve BP according to an embodiment of the present disclosure. Specifically, Figure 2 This is a graph showing the battery curve BP generated during the battery charging process.

[0055] exist Figure 2 In this implementation, the battery charging range can be divided into a CC range where charging is performed with a constant current and a CV range where charging is performed with a constant voltage. Preferably, since the CV range is a range where voltage changes are not significant, an inflection point may not occur. Therefore, the inflection point extraction unit 110 can extract the inflection point from the CC range of the battery curve BP.

[0056] The voltage corresponding to the inflection point in lithium-ion deposited batteries can be higher than that in normal batteries. (See below for reference.) Figure 3 and Figure 4 Describe in detail the inflection points of normal batteries and lithium deposition batteries.

[0057] Figure 3 This is a diagram schematically illustrating the voltage behavior of a standard battery R and a first battery B1 according to an embodiment of the present disclosure. Figure 4 This is a diagram schematically illustrating the voltage behavior of a standard battery R and a second battery B2 according to embodiments of the present disclosure.

[0058] Specifically Figure 3 and Figure 4 This is a graph showing the correspondence between voltage and differential voltage (dV / dt) in the CC interval. Here, differential voltage refers to the instantaneous rate of change of voltage with time.

[0059] exist Figure 3 and Figure 4 In this implementation, the standard battery R is a battery in the BOL (beginning of life) state and is a normal battery in which no lithium metal has been deposited. The first battery B1 is a battery in the MOL (middle of life) state and is a normal battery in which no lithium metal has been deposited. The second battery B2 is a battery in the MOL state and is a lithium deposition battery in which lithium metal has been deposited.

[0060] Reference Figure 3 and Figure 4 The inflection point of the standard battery R can occur at the standard voltage VR. The inflection point of the first battery B1 can occur at the first voltage VB1, while the inflection point of the second battery B2 can occur at the second voltage VB2. In other words, the voltage corresponding to the inflection point of the lithium-deposited battery can be greater than the voltage corresponding to the inflection point of the normal battery. Therefore, considering the standard voltage VR as the benchmark, the voltage corresponding to the inflection point of the lithium-deposited battery can be shifted towards a higher potential than the voltage corresponding to the inflection point of the normal battery.

[0061] Therefore, the inflection point extraction unit 110 can extract the inflection point from the battery curve BP, so that the control unit 120 can diagnose lithium deposition in the battery based on the voltage corresponding to the inflection point.

[0062] The control unit 120 can be configured to determine the target voltage, target temperature, and target current of the battery corresponding to the inflection point.

[0063] Specifically, during the charging or discharging process of a battery, not only the battery voltage but also the battery temperature and the charging and discharging current can be measured. In one embodiment, voltage, temperature, and current can be measured at the same or different time periods. Preferably, voltage, temperature, and current can be measured at the same time period. Here, current refers to the cumulative charging or discharging amount and can be calculated by current integration.

[0064] For example, in Figure 3 In this embodiment, the control unit 120 can determine the first voltage VB1 at the inflection point of the first battery B1 as the target voltage. Additionally, the first temperature corresponding to the target voltage can be determined as the target temperature. Furthermore, the first current quantity corresponding to the target voltage can be determined as the target current quantity. It should be noted here that the first temperature and first current quantity corresponding to the target voltage are the temperature and current quantities at the inflection point of the temperature and current quantity of the first battery B1 measured during the charging process.

[0065] The control unit 120 can be configured to determine a reference voltage in a preset voltmeter corresponding to the target temperature and the target current.

[0066] Here, the voltmeter can be a table that records the battery voltage based on the battery temperature and battery current. Specifically, the voltmeter is generated experimentally using a standard battery R in the BOL state, and can be a table in which the battery voltage is recorded for the battery temperature and current.

[0067] Figure 5 This is a schematic diagram illustrating a voltmeter VT according to an embodiment of the present disclosure.

[0068] Reference Figure 5 The voltmeter VT records voltage measurements at 5°C temperature intervals and 5A current intervals. For example, at a temperature of 20°C, voltages of 5A, 10A, and 15A are V1, V2, and V3, respectively. At a temperature of 25°C, voltages of 5A, 10A, and 15A are V4, V5, and V6, respectively. At a temperature of 30°C, voltages of 5A, 10A, and 15A are V7, V8, and V9, respectively.

[0069] In a non-limiting implementation Figure 5 For ease of explanation, only the corresponding voltages (V1 to V9) for a predetermined temperature range (20°C to 30°C) and a predetermined current range (5A to 15A) are shown. However, it should be noted that the temperature intervals and current intervals of the voltmeter VT are not affected by... Figure 5 Limitations of the implementation methods.

[0070] For example, in Figure 3 In this implementation, it is assumed that the target temperature corresponding to the first voltage VB1 is 25°C, and the corresponding target current is 10A. The control unit 120 can determine the reference voltage in the voltmeter VT corresponding to the target temperature and target current as V5.

[0071] The control unit 120 can be configured to diagnose whether lithium deposition has occurred in the battery based on a reference voltage and a target voltage.

[0072] Specifically, the control unit 120 can be configured to diagnose whether lithium deposition has occurred based on the voltage deviation between the reference voltage and the target voltage.

[0073] As mentioned above, refer to Figure 3 and Figure 4 Compared to the voltage corresponding to the inflection point of a normal battery, the voltage corresponding to the inflection point of a lithium-deposited battery can shift further towards a higher potential. Therefore, the control unit 120 can diagnose whether lithium deposition has occurred in the battery based on the voltage deviation between the reference voltage and the target voltage.

[0074] For example, if the voltage deviation is greater than or equal to a preset threshold voltage, the control unit 120 can be configured to diagnose lithium deposition in the battery. Conversely, if the voltage deviation is less than the threshold voltage, the control unit 120 can be configured to diagnose no lithium deposition in the battery. For example, the threshold voltage can be set to 10mV.

[0075] exist Figure 3 and Figure 4 In this implementation, it is assumed that the standard battery R, ​​the first battery B1, and the second battery B2 have the same temperature and current corresponding to the inflection point. That is, it is assumed that the standard voltage VR of the standard battery R is a reference voltage for the first battery B1 and the second battery B2. Since the first battery B1 is a normal battery, the voltage deviation between the standard voltage VR and the first voltage VB1 can be less than the threshold voltage. Since the second battery B2 is a lithium-deposited battery, the voltage deviation between the standard voltage VR and the second voltage VB2 can be greater than or equal to the threshold voltage. Therefore, the control unit 120 can diagnose the first battery B1 as a normal battery and the second battery B2 as a lithium-deposited battery.

[0076] In other words, the battery management device 100 according to the embodiments of this disclosure has the following advantages: it can quickly diagnose whether lithium deposition has occurred based on the battery curve BP (constant current charging and discharging curve).

[0077] In addition, since the battery management device 100 determines the reference voltage by taking into account the battery temperature and current, the accuracy of the diagnostic results can be improved by comparing the reference voltage with the target voltage.

[0078] Furthermore, 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. Additionally, 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 inside or outside the control unit 120 and can be connected to the control unit 120 by various known means.

[0079] Furthermore, the inflection point extraction unit 110 can extract multiple inflection points from the battery curve BP. Specifically, the inflection point extraction unit 110 can extract two or more inflection points from the CC interval of the battery curve BP.

[0080] In this case, the control unit 120 can determine the target voltage and reference voltage for each of the multiple inflection points, and calculate the voltage deviation between the corresponding target voltage and reference voltage.

[0081] Lithium deposition not only affects battery performance but can also cause fatal accidents such as fires and explosions. Therefore, the control unit 120 can diagnose lithium metal deposition in the battery if at least one of the calculated voltage deviations is equal to or greater than a threshold voltage.

[0082] In the following text, it will be through Figure 6 and Figure 7 This describes the reason for the increase in the target voltage corresponding to the inflection point during lithium deposition.

[0083] Figure 6 It is a schematic diagram showing the positive and negative electrode potential curves of a normal battery. Figure 7 It is a schematic diagram showing the positive and negative electrode potential curves of a lithium deposition battery.

[0084] exist Figure 6 and Figure 7 In the diagram, the upper curve represents the positive electrode potential curve, while the lower curve represents the negative electrode potential curve.

[0085] In a normal battery, the number of lithium ions moving between the positive and negative electrodes remains the same during charging and discharging. That is, in the case of a normal battery, assuming that the number of lithium ions moving from the positive electrode to the negative electrode during the charging process (from Q1 to Q2) is x, then the number of lithium ions moving to the positive electrode is also x.

[0086] exist Figure 6 In this implementation, during charging from Q1 to Q2, the positive electrode potential increases from Q1p to Q2p, and the negative electrode potential decreases from Q1n to Q2n. Conversely, during discharging from Q2 to Q1, the positive electrode potential can decrease from Q2p to Q1p, and the negative electrode potential can increase from Q2n to Q1n. Furthermore, at the inflection point appearing at Qx, the positive electrode potential can be Qxp and the negative electrode potential can be Qxn. Therefore, the voltage corresponding to the inflection point of a normal battery can be Qxp-Qxn.

[0087] On the other hand, in lithium-ion deposited batteries, because lithium metal is deposited on the negative electrode active material, the number of lithium ions transferred from the positive electrode to the negative electrode during charging can be greater than the number transferred from the negative electrode to the positive electrode during discharging. Due to this phenomenon, the positive electrode potential, corresponding to the negative electrode potential, shifts to a higher potential. Figure 7 In this implementation, at the inflection point appearing at Qx, the positive electrode potential can be Qxpp and the negative electrode potential can be Qxn. Therefore, the voltage corresponding to the inflection point of the lithium deposition battery can be Qxpp-Qxn.

[0088] Reference Figure 6 and Figure 7 The voltage (Qxpp-Qxn) corresponding to the inflection point of a lithium-deposited battery can be greater than the voltage (Qxp-Qxn) corresponding to the inflection point of a normal battery. Therefore, the battery management device 100 can take into account the voltage behavior of the battery in which lithium has been deposited and diagnose whether lithium deposition has occurred in the battery from the battery curve BP during the charging and discharging process.

[0089] Furthermore, since the battery management device 100 diagnoses lithium deposition by considering the voltage deviation between the target voltage corresponding to the inflection point and the reference voltage used as a standard, it has the advantage that it can diagnose whether lithium deposition has occurred even if lithium metal is slowly deposited.

[0090] The control unit 120 can be configured to determine a reference temperature corresponding to the target temperature, a reference current corresponding to the target current, and a reference voltage in the voltmeter VT corresponding to the reference temperature and the reference current.

[0091] The voltmeter VT can include voltages for multiple temperatures and multiple current quantities. Here, the multiple temperatures can be selected at predetermined temperature intervals. For example, in Figure 5In this implementation, the multiple temperatures can be selected at 5°C intervals.

[0092] Similarly, multiple current quantities can be current quantities selected at predetermined current quantity intervals. For example, in Figure 5 In this implementation, the multiple current quantities can be selected in 5A intervals.

[0093] In one embodiment, the control unit 120 may be configured to determine the temperature closest to the target temperature among a plurality of predetermined temperatures as a reference temperature, and the current quantity closest to the target current quantity among a plurality of predetermined current quantities as a reference current quantity.

[0094] For example, when the voltmeter VT does not contain a value that is the same as the target temperature and / or target current, the control unit 120 can determine the value in the voltmeter VT that is closest to the target temperature and / or target current as the reference temperature and / or reference current.

[0095] exist Figure 5 In this implementation, the target temperature is assumed to be 24°C and the target current is 8A. Since the voltmeter VT does not include a temperature equal to the target temperature, the control unit 120 can determine 25°C, which is closest to the target temperature of 24°C, as the reference temperature. Furthermore, since the voltmeter VT does not include a current equal to the target current, the control unit 120 can determine 10A, which is closest to the target current of 8A, as the reference current. Therefore, the control unit 120 can determine 5V, corresponding to the reference temperature (25°C) and the reference current (10A), as the reference voltage.

[0096] In addition, the control unit 120 can diagnose whether lithium deposition has occurred in the battery based on the comparison between the reference voltage 5V and the target voltage.

[0097] In another embodiment, the control unit 120 may be configured to determine at least one reference temperature among a plurality of predetermined temperatures that is within a predetermined temperature range from the target temperature.

[0098] For example, the predetermined temperature range can be set to an interval equal to the multiple temperatures included in the voltmeter VT. Figure 5 In this implementation, the predetermined temperature range can be 5°C.

[0099] In addition, the control unit 120 can be configured to determine at least one reference current quantity among a plurality of predetermined current quantities that is within the predetermined current quantity range of the target current quantity.

[0100] For example, a predetermined current range can be set to be equal to the current intervals of multiple currents included in the voltmeter VT. Figure 5In this implementation, the predetermined current range can be 5A.

[0101] The control unit 120 can be configured to determine the minimum voltage among at least one voltage based on a combination of at least one determined reference temperature and at least one determined reference current as the reference voltage.

[0102] For example, similar to the previous implementation, assuming the target temperature is 24°C and the target current is 8A, the control unit 120 can determine 20°C and 24°C, which are within 5°C of the target temperature from the multiple temperatures included in the voltmeter VT, as reference temperatures. Additionally, the control unit 120 can determine 5A and 10A, which are within 5A of the target current from the multiple currents included in the voltmeter VT, as reference currents. The control unit 120 can select V1, V2, V4, and V5 as candidates for reference voltages by combining the reference temperatures (20°C and 24°C) and the reference currents (5A and 10A). Furthermore, the control unit 120 can determine the minimum voltage among the selected V1, V2, V4, and V5 as the reference voltage.

[0103] In addition, the control unit 120 can diagnose whether lithium deposition has occurred in the battery based on the comparison between the reference voltage and the target voltage.

[0104] In another embodiment, the control unit 120 may be configured to determine a reference voltage corresponding to the target temperature and the target current by using an interpolation method when a plurality of predetermined temperatures do not have the same value as the target temperature or a plurality of predetermined currents do not have the same value as the target current.

[0105] Specifically, the control unit 120 can determine two reference temperatures in the voltmeter VT that are close to the target temperature. Additionally, the control unit 120 can determine two reference current quantities in the voltmeter VT that are close to the target current quantity. Furthermore, the control unit 120 determines four voltages based on the combination of the two reference temperatures and the two target current quantities, and determines reference voltages by interpolating the determined four voltages to correspond to the target temperature and target current quantities.

[0106] For example, as in the previous implementation, assuming the target temperature is 24°C and the target current is 8A, the control unit 120 can determine 20°C and 25°C, which are close to the target temperature, from among the multiple temperatures included in the voltmeter VT. Furthermore, the control unit 120 can determine 5A and 10A, which are close to the target current, from among the multiple currents included in the voltmeter VT. Additionally, the control unit 120 can determine the reference voltage by interpolating voltages V1, V2, V4, and V5 based on the combination of the reference temperature and the reference current.

[0107] As an example, the control unit 120 can interpolate the voltages corresponding to reference currents of 5A and 10A to correspond to a target current of 8A for each reference temperature. That is, the control unit 120 can calculate V12 by interpolating V1 and V2 at a ratio corresponding to the target current of 8A, and calculate V45 by interpolating V4 and V5 at a ratio corresponding to the target current of 8A. Here, the voltage corresponding to a reference temperature of 20°C and a target current of 8A can be V12, and the voltage corresponding to a reference temperature of 25°C and a target current of 8A can be V45.

[0108] Subsequently, the control unit 120 can determine the reference temperature by interpolating the interpolation voltages of V12 and V45 at a ratio corresponding to the target temperature of 24°C.

[0109] Preferably, the reference voltage can be determined using any of the various embodiments of determining the reference voltage from the voltmeter VT using the control unit 120, or multiple embodiments can be combined with each other to determine the reference voltage. Specifically, when the target voltage and / or target current are not included in the voltmeter VT, the final reference voltage can be determined by considering at least two of the following: 1) a reference voltage corresponding to the most recent temperature and current, 2) the minimum reference voltage among multiple voltages based on combinations of multiple temperatures and currents, and 3) a reference voltage based on an interpolation method. For example, the average or median of the multiple values ​​can be determined as the reference voltage.

[0110] Thus, the battery management device 100 according to the embodiments of this disclosure has the following advantages: It determines the reference voltage by considering the target temperature and target current, thereby more accurately diagnosing whether lithium deposition has occurred in the battery. Furthermore, since the reference voltage can be determined in various ways, the reliability and accuracy of the diagnostic results can be improved.

[0111] Reference Figure 1 The battery management device 100 may also include a storage unit 130.

[0112] Here, the battery management device 100 may further 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 is no specific limitation 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. Additionally, the storage unit 130 may store program code defining the processes executable by the control unit 120.

[0113] Specifically, the storage unit 130 can be communicatively connected to the inflection point extraction unit 110 and the control unit 120.

[0114] In addition, storage unit 130 can be configured to store voltmeter VT.

[0115] For example, storage unit 130 can store battery information such as the battery's voltage, temperature, and current when the battery is being charged or discharged. Additionally, storage unit 130 can store voltmeter VT.

[0116] The control unit 120 can access the storage unit 130 to first determine the target temperature and target current corresponding to the target voltage. Furthermore, the control unit 120 can determine the reference current corresponding to the target current and the reference temperature corresponding to the target temperature using a reference voltmeter VT. Finally, the control unit 120 can determine the reference voltage corresponding to the reference temperature and reference current using the reference voltmeter VT.

[0117] When a reference voltage corresponding to the target temperature and target current is pre-stored in the voltmeter VT stored in the storage unit 130 and the target voltage is less than the reference voltage, the control unit 120 can be configured to update the reference voltage to the target voltage.

[0118] In other words, when the target voltage is less than the reference voltage stored in the voltmeter VT, the control unit 120 can update the reference voltage to the target voltage.

[0119] As described above, when lithium metal is deposited in the battery, the positive electrode potential corresponding to the negative electrode potential shifts to a higher potential, so it is common for the target voltage to exceed the reference voltage. For example, when the target voltage is more than a threshold voltage higher than the reference voltage, the control unit 120 can diagnose lithium deposition in the battery.

[0120] Conversely, when the target voltage is lower than the reference voltage, the control unit 120 can update the reference voltage to the target voltage because a new voltage has emerged that has become the standard for determining whether lithium deposition has occurred.

[0121] For example, suppose the reference voltage is 3.46V and the target voltage is 3.45V. In this case, since the target voltage is less than the reference voltage, the control unit 120 can update the reference voltage to 3.45V.

[0122] By updating the reference voltage to a smaller value, it is possible to more rigorously determine whether lithium deposition has occurred in the battery. Therefore, the battery management device 100 has the advantage of more accurately diagnosing whether lithium deposition has occurred in the battery by appropriately updating the reference voltage.

[0123] 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 components of the battery management device 100 can be implemented by supplementing or adding the functions included in a conventional BMS. For example, the inflection point extraction unit 110, the control unit 120, and the storage unit 130 can be implemented as components of a BMS.

[0124] The battery management device 100 according to this disclosure can be disposed in a battery pack. That is, the battery pack according to this disclosure may include the aforementioned battery management device 100 and one or more battery cells. In addition, the battery pack may also include electrical equipment (relays, fuses, etc.) and a housing.

[0125] Figure 8 This is a diagram schematically illustrating an exemplary construction of a battery pack according to another embodiment of the present disclosure.

[0126] The positive terminal of battery B can be connected to the positive terminal P+ of battery pack 10, and the negative terminal of battery B can be connected to the negative terminal P- of battery pack 10.

[0127] The measurement unit 200 can be connected to the first sensing line SL1, the second sensing line SL2, the third sensing line SL3, and the fourth sensing line SL4.

[0128] Specifically, the measurement unit 200 can be connected to the positive terminal of the battery B via a first sensing line SL1, and to the negative terminal of the battery B via a second sensing line SL2. The measurement unit 200 can measure the voltage of the battery B based on the voltage measured at each of the first sensing line SL1 and the second sensing line SL2.

[0129] Additionally, the measurement unit 200 can be connected to the ammeter A via the third sensing line SL3. For example, the ammeter A can be an ammeter or a shunt resistor capable of measuring the charging and discharging currents of the battery B. The measurement unit 200 can calculate the charging current by measuring the charging current of the battery B via the third sensing line SL3. Furthermore, the measurement unit 200 can calculate the discharging current by measuring the discharging current of the battery B via the third sensing line SL3.

[0130] In addition, the measurement unit 200 is connected to the battery B via the fourth sensing line SL4, and can measure the temperature of the battery B during the charging process of the battery B.

[0131] The charging and discharging device 20 can be connected to the battery pack 10 and configured to charge and / or discharge the battery B.

[0132] Specifically, one end of the charging / discharging device 20 can be connected to the positive terminal P+ of the battery pack 10, and the other end can be connected to the negative terminal P- of the battery pack 10. Therefore, the positive terminal of battery B, the positive terminal P+ of battery pack 10, the charging / discharging device 20, the negative terminal P- of battery pack 10, and the negative terminal of battery B can be electrically connected.

[0133] Furthermore, the battery management device 100 according to this disclosure can be installed in a server.

[0134] Specifically, the server can be connected directly and / or indirectly to the BMS connected to the battery via wired / wireless networks. For example, the server could be a cloud server.

[0135] The server can be directly connected to the BMS, or indirectly connected to the BMS through other devices connected to the BMS. For example, a user terminal connected to the BMS can be connected to the server, or a charging device (e.g., a charger or charging station) connected to the BMS can be connected to the server.

[0136] The server can receive battery information (temperature, current, and voltage) and battery profile (BP) from the BMS. Furthermore, based on the received battery information and BP profile, the server can diagnose whether lithium deposition has occurred in the battery.

[0137] Figure 9 This is a schematic diagram illustrating a battery management method according to yet another embodiment of the present disclosure.

[0138] 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 omitted or briefly described.

[0139] Reference Figure 9 The battery management method may include an inflection point extraction step (S100), a target information determination step (S200), a reference voltage determination step (S300), and a lithium deposition diagnosis step (S400).

[0140] The inflection point extraction step (S100) is a step of extracting the inflection point in the battery curve BP, which represents the change of battery voltage over time, and can be executed by the inflection point extraction unit 110.

[0141] For example, in Figure 2 In one implementation, the inflection point extraction unit 110 can extract the inflection point in the CC interval of the battery curve BP.

[0142] The target information determination step (S200) is a step of determining the target voltage, target temperature and target current of the battery corresponding to the inflection point, and can be executed by the control unit 120.

[0143] For example, during the charging and discharging process of a battery, not only the battery voltage can be measured, but also the temperature and the charging and discharging current. Therefore, the control unit 120 can determine the target temperature and target current corresponding to the target voltage.

[0144] The reference voltage determination step (S300) is a step of determining the reference voltage in the preset voltmeter VT that corresponds to the target temperature and the target current, and can be executed by the control unit 120.

[0145] For example, the control unit 120 can first determine the reference temperature corresponding to the target temperature and the reference current corresponding to the target current in the voltmeter VT. Furthermore, the control unit 120 can determine the reference voltage corresponding to the reference temperature and the reference current in the voltmeter VT.

[0146] The lithium deposition diagnostic step (S400) is a step to diagnose whether lithium deposition has occurred in the battery based on a reference voltage and a target voltage, and can be executed by the control unit 120.

[0147] For example, control unit 120 can calculate the voltage deviation between a reference voltage and a target voltage. Furthermore, if the voltage deviation is equal to or greater than a preset threshold voltage, control unit 120 can be configured to diagnose lithium deposition in the battery. Conversely, if the voltage deviation is less than the threshold voltage, control unit 120 can be configured to diagnose no lithium deposition in the battery. For example, the threshold voltage can be set to 10mV.

[0148] The embodiments 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 by a recording medium on which the program is recorded. Based on the description of the embodiments above, those skilled in the art can easily implement the program or recording medium.

[0149] 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 variations and modifications within the scope of this disclosure will become clear to those skilled in the art based on the detailed description.

[0150] Additionally, without departing from the technical aspects of this disclosure, those skilled in the art can make many substitutions, modifications and variations to the disclosure described above, 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 for various modifications.

[0151] (See attached image labels)

[0152] 10: Battery Pack

[0153] 20: Charging and discharging device

[0154] 100: Battery Management Device

[0155] 110: Inflection Point Extraction Unit

[0156] 120: Control Unit

[0157] 130: Storage unit

[0158] 200: Unit of measurement

Claims

1. A battery management device, the battery management device comprising: Inflection point extraction unit, configured to extract inflection points from a battery curve representing the change of battery voltage over time; as well as A control unit is configured to determine a target voltage, a target temperature, and a target current of the battery corresponding to the inflection point; determine a reference voltage in a voltmeter corresponding to the target temperature and the target current; and diagnose whether lithium deposition has occurred in the battery based on the reference voltage and the target voltage. The voltmeter is a preset meter that is tested using a standard battery that is at the beginning of its lifespan and has not deposited lithium metal at different temperatures and currents, and the voltmeter records the voltage of the battery based on the battery temperature and the battery current.

2. The battery management device according to claim 1, in, The control unit is configured to diagnose whether lithium deposition has occurred based on the voltage deviation between the reference voltage and the target voltage.

3. The battery management device according to claim 2, in, The control unit is configured to diagnose lithium deposition in the battery when the voltage deviation is equal to or greater than a preset threshold voltage, and The control unit is configured to diagnose that no lithium deposition has occurred in the battery when the voltage deviation is less than the preset threshold voltage.

4. The battery management device according to claim 1, in, The control unit is configured to determine a reference temperature corresponding to the target temperature, a reference current corresponding to the target current, and a reference voltage in the voltmeter corresponding to the reference temperature and the reference current.

5. The battery management device according to claim 4, in, The control unit is configured to determine the temperature closest to the target temperature among a plurality of predetermined temperatures as the reference temperature, and to determine the current closest to the target current among a plurality of predetermined current quantities as the reference current quantity.

6. The battery management device according to claim 4, in, The control unit is configured to determine at least one reference temperature from a plurality of predetermined temperatures that is within a predetermined temperature range from the target temperature, to determine at least one reference current from a plurality of predetermined currents that is within a predetermined current range from the target current, and to determine the minimum voltage from at least one voltage based on a combination of the determined at least one reference temperature and the determined at least one reference current as the reference voltage.

7. The battery management device according to claim 4, in, The control unit is configured to determine, by using an interpolation method, a reference voltage in the voltmeter corresponding to the target temperature and the target current when multiple predetermined temperatures do not have the same value as the target temperature or multiple predetermined currents do not have the same value as the target current.

8. The battery management device according to claim 1, in, The battery curve is a record showing the voltage based on the charging or discharging time when the battery is charged or discharged with a constant current.

9. The battery management device according to claim 1, further comprising: A storage unit configured to store the voltmeter. The control unit is configured to pre-store the reference voltage corresponding to the target temperature and the target current in the voltage table stored in the storage unit, and to update the reference voltage to the target voltage when the target voltage is less than the reference voltage.

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

11. The battery pack of claim 10, further comprising a measuring unit connected to the positive terminal of the battery via a first sensing line and connected to the negative terminal of the battery via a second sensing line, and The measuring unit measures the voltage of the battery based on the voltage measured at each of the first and second sensing lines.

12. The battery pack according to claim 11, wherein, The measuring unit is connected via a third sensing line to an ammeter that measures the charging and discharging currents of the battery.

13. The battery pack according to claim 11, wherein, The measuring unit is connected to the battery via a fourth sensing line and measures the battery temperature during the charging process.

14. A battery management server comprising the battery management device according to any one of claims 1 to 9.

15. A battery management method, the battery management method comprising the following steps: Inflection point extraction step, which extracts inflection points from the battery curve representing the change of battery voltage over time. The target information determination step determines the target voltage, target temperature, and target current of the battery corresponding to the inflection point. A reference voltage determination step, which determines a reference voltage in a preset voltage table corresponding to the target temperature and the target current; as well as A lithium deposition diagnostic step, which diagnoses whether lithium deposition has occurred in the battery based on the reference voltage and the target voltage. The voltmeter is a preset meter that is tested using a standard battery that is at the beginning of its lifespan and has not deposited lithium metal at different temperatures and currents, and the voltmeter records the voltage of the battery based on the battery temperature and the battery current.

16. The battery management method according to claim 15, wherein, In the lithium deposition diagnosis step, the presence of lithium deposition is diagnosed based on the voltage deviation between the reference voltage and the target voltage.

17. The battery management method according to claim 16, wherein, In the lithium deposition diagnostic step: When the voltage deviation is equal to or greater than a preset threshold voltage, lithium deposition in the battery is diagnosed, and When the voltage deviation is less than the preset threshold voltage, it is diagnosed that no lithium deposition has occurred in the battery.

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