Battery management device and method

Abstract

According to an embodiment of the present invention, a battery management device includes an inflection point extraction unit configured to extract an inflection point from a battery profile indicating a change in a voltage of a battery over time; and a control unit configured to determine a target voltage, a target temperature, and a target current amount of a battery corresponding to the inflection point, determine a reference voltage corresponding to the target temperature and the target current amount from a preset voltage table, and diagnose whether or not lithium is precipitated in the battery based on the reference voltage and the target voltage.

Description

[Technical field]

[0001] This application claims priority to Korean Patent Application No. 10-2022-0016361, filed on February 8, 2022, the entire contents of which are incorporated herein by reference in their entirety in the specification and drawings.

[0002] The present invention relates to a battery management device and method, and more particularly to a battery management device and method capable of diagnosing the presence or absence of lithium deposition in a battery. [Background technology]

[0003] In recent years, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has grown rapidly and the development of electric vehicles, energy storage batteries, robots, satellites, and other products has accelerated, active research is being conducted into high-performance batteries that can be repeatedly charged and discharged.

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. Of these, lithium batteries are in the spotlight for their advantages over nickel-based batteries, such as the fact that they have almost no memory effect and can be charged and discharged freely, as well as their extremely low self-discharge rate and high energy density.

[0005] Although a great deal of research has been conducted on these batteries from the viewpoints of increasing capacity and density, improving their lifespan and safety is also important. To achieve this, it is necessary to suppress the decomposition reaction with the electrolyte on the surface of the electrodes, and to prevent overcharging and overdischarging.

[0006] In particular, it is necessary to prevent the phenomenon of lithium deposition on the surface of the negative electrode (lithium plating). If lithium is deposited on the surface of the negative electrode, it may cause side reactions with the electrolyte and changes in the kinetic balance of the battery, which may lead to battery degradation. In addition, as lithium metal is deposited on the surface of the negative electrode, there is a risk of an internal short circuit in the battery, which may result in fire or explosion.

[0007] In the past, the presence or absence of lithium deposition was diagnosed based on the change in voltage over time during a rest period after charging. However, this method is applicable only when lithium deposition is severe during the rest period, and has a problem in that it is not possible to accurately diagnose the presence or absence of lithium deposition when lithium deposition accumulates little by little.

[0008] Therefore, it is desirable to develop a technique that can accurately diagnose lithium deposition even when the deposition occurs gradually and cumulatively. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been devised to solve the above problems, and aims to provide a battery management device and method for diagnosing the presence or absence of lithium deposition in a battery based on an inflection point voltage in a battery profile that indicates a change in voltage over time.

[0010] Other objects and advantages of the present invention will become apparent from the following description and the embodiments of the present invention, and can be realized by the means and combinations thereof as claimed in the appended claims. [Means for solving the problem]

[0011] A battery management device according to one aspect of the present invention may include an inflection point extraction unit configured to extract an inflection point from a battery profile indicating a change in battery voltage over time, and a control unit configured to determine a target voltage, a target temperature, and a target current amount of the battery corresponding to the inflection point, determine a reference voltage corresponding to the target temperature and the target current amount in a preset voltage table, and diagnose whether or not lithium is precipitated in the battery based on the reference voltage and the target voltage.

[0012] The control unit may be configured to diagnose whether or not lithium is deposited based on a voltage deviation between the reference voltage and the target voltage.

[0013] The control unit may be configured to diagnose that the lithium has been deposited in the battery if the voltage deviation is equal to or greater than a preset threshold voltage.

[0014] The control unit may be configured to diagnose that the lithium is not deposited in the battery if the voltage deviation is less than the threshold voltage.

[0015] The control unit may be configured to determine a reference temperature corresponding to the target temperature, determine a reference current amount corresponding to the target current amount, and determine the reference voltage corresponding to the reference temperature and the reference current amount in the voltage table.

[0016] The control unit may be configured to determine, among a plurality of predetermined temperatures, a temperature closest to the target temperature as the reference temperature, and to determine, among a plurality of predetermined current amounts, a current amount closest to the target current amount as the reference current amount.

[0017] The control unit may be configured to determine one or more reference temperatures among a plurality of predetermined temperatures that fall within a predetermined temperature range from the target temperature, determine one or more reference current amounts among a plurality of predetermined current amounts that fall within a predetermined current amount range from the target current amount, and determine a minimum voltage among one or more voltages resulting from a combination of the determined one or more reference temperatures and one or more reference current amounts as the reference voltage.

[0018] The control unit may be configured to use an interpolation method to determine the reference voltage corresponding to the target temperature and the target current amount in the voltage table when none of the predetermined temperatures has a value identical to the target temperature, or when none of the predetermined current amounts has a value identical to the target current amount.

[0019] The voltage table may be a table in which the voltage of the battery according to the temperature of the battery and the amount of current of the battery is recorded.

[0020] The battery profile may be a profile recorded showing the voltage over charge or discharge time when the battery is charged or discharged at a constant current.

[0021] The battery management device according to another aspect of the present invention may further include a storage unit configured to store the voltage table.

[0022] The control unit may be configured such that the reference voltage corresponding to the target temperature and the target current amount is pre-stored in the voltage table stored in the storage unit, and if the target voltage is less than the reference voltage, the reference voltage is updated to the target voltage.

[0023] A battery pack according to yet another aspect of the present invention may include the battery management device according to one aspect of the present invention.

[0024] A battery management server according to yet another aspect of the present invention may include the battery management device according to one aspect of the present invention.

[0025] A battery management method according to yet another aspect of the present invention may include an inflection point extraction step of extracting an inflection point from a battery profile indicating a change in battery voltage over time; a target information determination step of determining a target voltage, a target temperature, and a target current amount of the battery corresponding to the inflection point; a reference voltage determination step of determining a reference voltage corresponding to the target temperature and the target current amount in a preset voltage table; and a lithium precipitation diagnosis step of diagnosing the presence or absence of lithium precipitation in the battery based on the reference voltage and the target voltage. Effect of the Invention

[0026] According to one aspect of the present invention, it is possible to accurately diagnose whether or not lithium metal is precipitated in a battery. In particular, even if the precipitation of lithium metal occurs gradually, it is possible to diagnose whether or not lithium metal is precipitated.

[0027] Furthermore, according to one aspect of the present invention, the presence or absence of lithium deposition can be quickly diagnosed based on measurement data during the charge and discharge process of a battery.

[0028] The effects of the present invention are not limited to those described above, and other effects not mentioned herein will be clearly understood by those skilled in the art from the description of the claims.

[0029] The drawings attached to this specification are intended to illustrate preferred embodiments of the present invention and serve to facilitate a further understanding of the technical ideas of the present invention as well as the content of the invention, and therefore the present invention should not be interpreted as being limited to only the matters depicted in the drawings. [Brief description of the drawings]

[0030] [Figure 1]1 is a diagram illustrating a battery management device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a schematic diagram illustrating a battery profile according to an embodiment of the present invention. [Diagram 3] FIG. 4 is a schematic diagram illustrating the voltage behavior of a reference battery and a first battery according to an embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram illustrating the voltage behavior of a reference battery and a second battery according to an embodiment of the present invention. [Diagram 5] FIG. 4 is a schematic diagram of a voltage table according to an embodiment of the present invention. [Figure 6] FIG. 2 is a diagram showing a schematic diagram of a positive electrode potential curve and a negative electrode potential curve of a normal battery; [Figure 7] FIG. 2 is a schematic diagram showing the positive and negative electrode potential curves of a lithium-precipitated battery; [Figure 8] FIG. 2 is a schematic diagram illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention. [Figure 9] 11 is a diagram illustrating a battery management method according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The terms and words used in this specification and the claims should not be interpreted in a limited manner to their ordinary or dictionary meanings, but should be interpreted in a manner that corresponds to the technical idea of ​​the present invention, based on the principle that the inventor himself can appropriately define the concept of the term in order to explain the invention in the best possible way.

[0032] Therefore, it should be understood that the embodiment described in this specification and the configurations shown in the drawings are merely the most preferred embodiment of the present invention and do not represent the entire technical idea of ​​the present invention, and therefore there may be various equivalents and modifications that can be substituted therefor at the time of this application.

[0033] In describing the present invention, detailed descriptions of known configurations or functions related to the present invention will be omitted if it is deemed that such descriptions may unnecessarily obscure the gist of the present invention.

[0034] Terms including ordinal numbers such as first, second, etc. are used to distinguish one of various components from the other components, and are not intended to limit the components.

[0035] Throughout the specification, when a part is said to "comprise" a certain element, this means that it may further include other elements, not excluding other elements, unless otherwise specified.

[0036] In addition, throughout this specification, when it is said that a part is "connected (coupled)" to another part, this includes not only the case where it is "directly connected (coupled)" to another part, but also the case where it is "indirectly connected (coupled)" via another element in between.

[0037] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0038] FIG. 1 is a diagram illustrating a battery management device 100 according to an embodiment of the present invention.

[0039] Specifically, the battery management device 100 can diagnose whether or not lithium metal has been deposited on the battery. Here, the battery means an independent cell that has a negative terminal and a positive terminal and can be physically separated. As an example, a lithium ion battery or a lithium polymer battery can be regarded as a battery.

[0040] Referring to FIG. 1, a battery management device 100 may include an inflection point extraction unit 110 and a control unit 120.

[0041] The inflection point extractor 110 may be configured to extract inflection points from a battery profile (BP) that indicates changes in the voltage of a battery over time.

[0042] Here, the battery profile (BP) may be a profile that is generated during the process of charging or discharging a battery and indicates a change in the voltage of the battery over time. Preferably, the battery profile (BP) may be a profile recorded to indicate the voltage over the charging or discharging time when the battery is charged or discharged at a constant current.

[0043] 2 is a diagram illustrating a battery profile (BP) according to an embodiment of the present invention. Specifically, FIG. 2 is a diagram illustrating a battery profile (BP) generated during a process in which a battery is charged.

[0044] In the embodiment of Fig. 2, the charging section of the battery may be divided into a CC section where charging is performed at a constant current and a CV section where charging is performed at a constant voltage. Preferably, the CV section is a section where the change in voltage is not significant, and therefore an inflection point may not appear. Therefore, the inflection point extraction unit 110 may extract an inflection point from the CC section of the battery profile (BP).

[0045] The voltage corresponding to the inflection point of the lithium-deposited battery may be greater than the voltage corresponding to the inflection point of the normal battery. The inflection points of the normal battery and the lithium-deposited battery are described in detail with reference to Figures 3 and 4 below.

[0046] 3 is a diagram illustrating the voltage behavior of a reference battery R and a first battery B1 according to an embodiment of the present invention. FIG. 4 is a diagram illustrating the voltage behavior of a reference battery R and a second battery B2 according to an embodiment of the present invention.

[0047] 3 and 4 are diagrams showing the relationship between the voltage and the differential voltage (dV / dt) in the CC section, where the differential voltage means the instantaneous rate of change of the voltage over time.

[0048] In the embodiment of Figures 3 and 4, the reference battery R is a battery in the beginning of life (BOL) state and is a normal battery with no lithium metal precipitated. The first battery B1 is a battery in the middle of life (MOL) state and is a normal battery with no lithium metal precipitated. The second battery B2 is a battery in the MOL state and is a lithium precipitated battery with lithium metal precipitated.

[0049] 3 and 4, the inflection point of the reference battery R may appear at the reference voltage VR. The inflection point of the first battery B1 may appear at the first voltage VB1, and the inflection point of the second battery B2 may appear at the second voltage VB2. That is, the voltage corresponding to the inflection point of the lithium-deposited battery may be higher than the voltage corresponding to the inflection point of the normal battery. Therefore, when the reference voltage VR is taken as a reference, the voltage corresponding to the inflection point of the lithium-deposited battery may be shifted further toward a higher potential side than the voltage corresponding to the inflection point of the normal battery.

[0050] Therefore, the inflection point extracting unit 110 can extract an inflection point from the battery profile (BP) so that the control unit 120 can diagnose whether or not lithium is deposited in the battery based on the voltage corresponding to the inflection point.

[0051] The controller 120 may be configured to determine a target voltage, a target temperature, and a target current amount of the battery that correspond to the inflection point.

[0052] Specifically, in the process of charging or discharging the battery, not only the voltage of the battery but also the temperature of the battery and the charge / discharge current amount may be measured. In one embodiment, the voltage, temperature, and current amount may be measured in the same or different cycles. Preferably, the voltage, temperature, and current amount may be measured in the same cycle. Here, the current amount means the accumulated charge amount or accumulated discharge amount, and can be calculated by integrating the current.

[0053] For example, in the embodiment of FIG. 3, the control unit 120 may determine the first voltage VB1 at which an inflection point of the first battery B1 appears as the target voltage. Then, the control unit 120 may determine the first temperature corresponding to the target voltage as the target temperature. Also, the control unit 120 may determine the first current amount corresponding to the target voltage as the target current amount. Here, it should be noted that the first temperature and the first current amount corresponding to the target voltage are the temperature and the current amount at the time when the inflection point appears among the temperatures and the current amounts of the first battery B1 measured during the charging process.

[0054] The control unit 120 may be configured to determine a reference voltage corresponding to a target temperature and a target current amount in a preset voltage table.

[0055] Here, the voltage table may be a table in which the battery voltage according to the battery temperature and the battery current amount is recorded. Specifically, the voltage table may be generated through an experiment using a reference battery R in a BOL state, and may be a table in which the battery voltage with respect to the battery temperature and the battery current amount is recorded.

[0056] FIG. 5 is a schematic diagram of a voltage table (VT) according to an embodiment of the present invention.

[0057] 5, the voltage table (VT) may record voltages measured for each temperature of 5° C. and each current of 5 A. For example, when the temperature is 20° C., the voltages when the currents are 5 A, 10 A, and 15 A are V1, V2, and V3, respectively. When the temperature is 25° C., the voltages when the currents are 5 A, 10 A, and 15 A are V4, V5, and V6, respectively. When the temperature is 30° C., the voltages when the currents are 5 A, 10 A, and 15 A are V7, V8, and V9, respectively.

[0058] 5, which is a non-limiting embodiment, shows voltages V1 to V9 corresponding only to a predetermined temperature range (20° C. to 30° C.) and a predetermined current amount range (5 A to 15 A) for ease of explanation. However, it should be noted that the temperature intervals and current amount intervals of the voltage table (VT) are not limited in any way by the embodiment of FIG.

[0059] 3, assume that the target temperature corresponding to the first voltage VB1 is 25° C. and the corresponding target current amount is 10 A. The control unit 120 may determine the reference voltage corresponding to the target temperature and the target current amount as V5 in the voltage table (VT).

[0060] The control unit 120 may be configured to diagnose whether or not lithium has been deposited in the battery based on the reference voltage and the target voltage.

[0061] Specifically, the control unit 120 may be configured to diagnose whether or not lithium has been deposited based on the voltage deviation between the reference voltage and the target voltage.

[0062] 3 and 4, the voltage corresponding to the inflection point of the lithium-deposited battery may be shifted further toward the high potential side compared to the voltage corresponding to the inflection point of the normal battery. Therefore, the control unit 120 may diagnose whether or not lithium is deposited in the battery based on the voltage deviation between the reference voltage and the target voltage.

[0063] For example, if the voltage deviation is equal to or greater than a preset threshold voltage, the control unit 120 may be configured to diagnose that lithium has been deposited in the battery. Conversely, if the voltage deviation is less than the threshold voltage, the control unit 120 may be configured to diagnose that lithium has not been deposited in the battery. For example, the threshold voltage may be set to 10 mV.

[0064] In the embodiments of Figs. 3 and 4, it is assumed that the temperatures and current amounts corresponding to the inflection points of the reference battery R, ​​the first battery B1, and the second battery B2 are the same. That is, it is assumed that the reference voltage VR for the reference 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 reference voltage VR and the first voltage VB1 may be less than the threshold voltage. Since the second battery B2 is a lithium deposition battery, the voltage deviation between the reference voltage VR and the second voltage VB2 may be greater than or equal to the threshold voltage. Therefore, the control unit 120 may diagnose the first battery B1 as a normal battery and the second battery B2 as a lithium deposition battery.

[0065] That is, the battery management device 100 according to an embodiment of the present invention has an advantage in that it can quickly diagnose whether or not lithium has been deposited based on a battery profile (BP) (constant current charge / discharge profile).

[0066] In addition, since the battery management device 100 determines the reference voltage in consideration of the temperature and current of the battery, the accuracy of the diagnosis result can be improved by comparing the reference voltage with the target voltage.

[0067] Meanwhile, the control unit 120 provided in the battery management device 100 may selectively include a processor, an application specific integrated circuit (ASIC), other chipsets, logic circuits, registers, a communication modem, a data processing device, etc., known in the art, in order to activate various control logics performed in the present invention. Also, when the control logic is realized by software, the control unit 120 may be realized by a collection of program modules. In this case, the program modules may be stored in a memory and may be activated by the control unit 120. The memory may be inside or outside the control unit 120, and may be connected to the control unit 120 by various well-known means.

[0068] On the other hand, the inflection point extraction unit 110 may extract a plurality of inflection points from the battery profile (BP). Specifically, the inflection point extraction unit 110 may extract two or more inflection points from the CC section of the battery profile (BP).

[0069] In this case, the control unit 120 may determine a target voltage and a reference voltage for each of the multiple inflection points, and calculate a voltage deviation between the corresponding target voltage and the reference voltage.

[0070] Lithium deposition not only affects the performance of the battery, but may also cause fatal accidents such as fires and explosions. Therefore, if at least one of the calculated voltage deviations is equal to or greater than a threshold voltage, the control unit 120 may diagnose that lithium metal has been deposited in the battery.

[0071] Hereinafter, the reason why the target voltage corresponding to the inflection point increases when lithium is deposited will be described with reference to FIGS.

[0072] 6 is a schematic diagram showing the positive and negative electrode potential curves of a normal battery, and FIG. 7 is a schematic diagram showing the positive and negative electrode potential curves of a lithium-precipitated battery.

[0073] 6 and 7, the upper curve is a positive electrode potential curve, and the lower curve is a negative electrode potential curve.

[0074] In a normal battery, the number of lithium ions moving between the positive and negative electrodes during charging and discharging is kept the same. That is, in the case of a normal battery, when the number of lithium ions moving from the positive electrode to the negative electrode during the charging process (process from Q1 to Q2) is x, the number of lithium ions moving from the negative electrode to the positive electrode during the discharging process (process from Q2 to Q1) is also x.

[0075] In the embodiment of Fig. 6, 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 may decrease from Q2p to Q1p, and the negative electrode potential may increase from Q2n to Q1n. Then, at the inflection point appearing at Qx, the positive electrode potential may be Qxp, and the negative electrode potential may be Qxn. Therefore, the voltage corresponding to the inflection point of a normal battery may be Qxp-Qxn.

[0076] In contrast, in a lithium deposition battery, since 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 may be greater than the number of lithium ions 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. In the embodiment of FIG. 7, at the inflection point appearing at Qx, the positive electrode potential may be Qxpp and the negative electrode potential may be Qxn. Therefore, the voltage corresponding to the inflection point of the lithium deposition battery may be Qxpp-Qxn.

[0077] 6 and 7, the voltage (Qxpp-Qxn) corresponding to the inflection point of the lithium-deposited battery may be greater than the voltage (Qxp-Qxn) corresponding to the inflection point of the normal battery. Therefore, the battery management device 100 can diagnose whether or not lithium is deposited in the battery from the battery profile (BP) of the charge and discharge process, taking into account the voltage behavior of the battery in which lithium is deposited.

[0078] In addition, the battery management device 100 diagnoses whether or not lithium has been precipitated by taking into account the voltage deviation between the target voltage corresponding to the inflection point and the reference voltage serving as a standard. This has the advantage that it is possible to diagnose whether or not lithium has been precipitated even if lithium metal precipitates gradually.

[0079] The control unit 120 may be configured to determine a reference temperature corresponding to the target temperature, determine a reference current amount corresponding to the target current amount, and determine a reference voltage corresponding to the reference temperature and the reference current amount in a voltage table (VT).

[0080] The voltage table (VT) may include voltages for multiple temperatures and multiple current amounts. Here, the multiple temperatures may be temperatures selected at predetermined temperature intervals. For example, in the embodiment of FIG. 5, the multiple temperatures may be temperatures selected at 5° C. intervals.

[0081] Similarly, the multiple current amounts may be current amounts selected at predetermined current amount intervals. For example, in the embodiment of FIG. 5, the multiple current amounts may be current amounts selected at 5A intervals.

[0082] In one embodiment, the control unit 120 may be configured to determine, among a plurality of predetermined temperatures, a temperature closest to the target temperature as a reference temperature, and to determine, among a plurality of predetermined current amounts, a current amount closest to the target current amount as a reference current amount.

[0083] For example, if the voltage table (VT) does not contain a value identical to the target temperature and / or the target current amount, the control unit 120 may determine a value in the voltage table (VT) that is closest to the target temperature and / or the target current amount as the reference temperature and / or the reference current amount.

[0084] In the embodiment of FIG. 5, assume that the target temperature is 24° C. and the target current amount is 8 A. Since the voltage table (VT) does not include a temperature equal to the target temperature, the control unit 120 may determine 25° C., which is closest to the target temperature of 24° C., as the reference temperature. Since the voltage table (VT) does not include a current amount equal to the target current amount, the control unit 120 may determine 10 A, which is closest to the target current amount of 8 A, as the reference current amount. Therefore, the control unit 120 may determine 5 V, which corresponds to the reference temperature of 24° C. and the reference current amount of 10 A, as the reference voltage.

[0085] Then, the control unit 120 can diagnose whether or not lithium is deposited in the battery based on the result of comparing the reference voltage 5V with the target voltage.

[0086] In another embodiment, the control unit 120 may be configured to determine one or more reference temperatures from a plurality of pre-determined temperatures that fall within a predetermined temperature range from the target temperature.

[0087] For example, the predetermined temperature range may be set to be equal to the temperature interval of the temperatures included in the voltage table (VT). In the embodiment of FIG. 5, the predetermined temperature range may be 5° C.

[0088] Furthermore, the control unit 120 may be configured to determine one or more reference current amounts that fall within a predetermined current amount range from the target current amount, from among a plurality of predetermined current amounts.

[0089] For example, the predetermined current amount range may be set to be equal to the current amount interval of the multiple current amounts included in the voltage table (VT). In the embodiment of FIG.

[0090] The control unit 120 may be configured to determine, as the reference voltage, a minimum voltage among one or more voltages resulting from combinations of the determined one or more reference temperatures and one or more reference current amounts.

[0091] For example, as in the above-described embodiment, assume that the target temperature is 24° C. and the target current amount is 8 A. The control unit 120 may determine, as the reference temperatures, 20° C. and 24° C., which are within a range of 5° C. from the target temperature, from among the multiple temperatures included in the voltage table (VT). The control unit 120 may then determine, as the reference current amounts, 5 A and 10 A, which are within a range of 5 A from the target current amount, from among the multiple current amounts included in the voltage table (VT). The control unit 120 may combine the reference temperatures 20° C. and 24° C. with the reference current amounts 5 A and 10 A, and select V1, V2, V4, and V5 as candidates for the reference voltage. The control unit 120 may then determine, as the reference voltage, the minimum voltage of the selected V1, V2, V4, and V5.

[0092] The control unit 120 can then diagnose whether or not lithium has been deposited in the battery based on the result of comparing the reference voltage with the target voltage.

[0093] In yet another embodiment, the control unit 120 may be configured to use an interpolation method to determine a reference voltage corresponding to the target temperature and the target current amount in the voltage table (VT) when the predetermined plurality of temperatures does not have a value equal to the target temperature or when the predetermined plurality of current amounts does not have a value equal to the target current amount.

[0094] Specifically, the control unit 120 may determine two reference temperatures close to the target temperature in the voltage table (VT). The control unit 120 may also determine two reference current amounts close to the target current amounts in the voltage table (VT). The control unit 120 may then determine four voltages based on combinations of the two reference temperatures and the two target current amounts, and may determine the reference voltages by interpolating the determined four voltages so as to correspond to the target temperatures and the target current amounts.

[0095] For example, as in the above-described embodiment, assume that the target temperature is 24° C. and the target current amount is 8 A. The control unit 120 may determine, as the reference temperatures, 20° C. and 25° C., which are close to the target temperature, from among the multiple temperatures included in the voltage table (VT). The control unit 120 may also determine, as the reference current amounts, 5 A and 10 A, which are close to the target current amount, from among the multiple current amounts included in the voltage table (VT). The control unit 120 may then determine the reference voltages by interpolating the V1, V2, V4, and V5 voltages based on the combinations of the reference temperatures and the reference current amounts.

[0096] As an example, the control unit 120 may interpolate voltages corresponding to reference current amounts of 5 A and 10 A so as to correspond to a target current amount of 8 A for each of the reference temperatures. That is, the control unit 120 may calculate V12 by interpolating V1 and V2 at a ratio corresponding to the target current amount of 8 A, and calculate V45 by interpolating V4 and V5 at a ratio corresponding to the target current amount of 8 A. Here, the voltage corresponding to a reference temperature of 20° C. and the target current amount of 8 A may be V12, and the voltage corresponding to a reference temperature of 25° C. and the target current amount of 8 A may be V45.

[0097] The control unit 120 may then determine the reference temperature by interpolating the interpolated voltages V12 and V45 at a ratio corresponding to the target temperature of 24°C.

[0098] Preferably, any one of various embodiments in which the control unit 120 determines the reference voltage in the voltage table (VT) may be applied to determine the reference voltage, or a plurality of embodiments may be combined with each other to determine the reference voltage. In particular, when the target voltage and / or the target current amount are not included in the voltage table (VT), the final reference voltage may be determined by considering at least two or more values ​​of 1) the reference voltage corresponding to the closest temperature and current amount, 2) the minimum reference voltage among the plurality of voltages according to the combination of the plurality of temperatures and current amounts, and 3) the reference voltage by the interpolation method. For example, the average value or the median value of the plurality of values ​​may be determined as the reference voltage.

[0099] As described above, the battery management device 100 according to an embodiment of the present invention has an advantage that it can determine the reference voltage in consideration of the target temperature and the target current amount in order to more accurately diagnose whether or not lithium is precipitated in the battery. Also, since the reference voltage can be determined in various manners, it is possible to improve the reliability and accuracy of the diagnosis result.

[0100] Referring to FIG. 1, the battery management device 100 may further include a storage section 130.

[0101] Here, the storage unit 130 may store data or programs required for each component of the battery management device 100 to operate and function, or data generated in the process of operating and functioning. The storage unit 130 is not particularly limited in type as long as it is a known information storage means known to be capable of writing, erasing, updating, and reading data. As an example, the information storage means may include a random access memory (RAM), a flash memory, a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a register, and the like. The storage unit 130 may also store a program code in which a process that can be activated by the control unit 120 is defined.

[0102] Specifically, the storage unit 130 can be connected to the inflection point extraction unit 110 and the control unit 120 so as to be able to communicate with them.

[0103] The storage unit 130 may also be configured to store a voltage table (VT).

[0104] For example, the storage unit 130 may store battery information regarding the voltage, temperature and amount of current of the battery while the battery is being charged or discharged, and may store a voltage table (VT).

[0105] The control unit 120 may first determine a target temperature and a target current amount corresponding to a target voltage by accessing the storage unit 130. Then, the control unit 120 may determine a reference current amount corresponding to the target current amount and a reference temperature corresponding to the target temperature by referring to the voltage table (VT). Finally, the control unit 120 may determine a reference voltage corresponding to the reference temperature and the reference current amount by referring to the voltage table (VT).

[0106] When a reference voltage corresponding to a target temperature and a target current amount is pre-stored in the voltage table (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.

[0107] That is, if the target voltage is less than the reference voltage stored in the voltage table (VT), the control unit 120 may update the reference voltage to the target voltage.

[0108] 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 that the target voltage generally exceeds the reference voltage. For example, the control unit 120 may diagnose that lithium is deposited in the battery if the target voltage is equal to or higher than the threshold voltage from the reference voltage.

[0109] Conversely, if the target voltage is less than the reference voltage, a new voltage that serves as a criterion for determining whether or not lithium has been deposited has appeared, and therefore the control unit 120 may update the reference voltage to the target voltage.

[0110] For example, assume that the reference voltage is 3.46 V and the target voltage is 3.45 V. In this case, since the target voltage is smaller than the reference voltage, the control unit 120 may update the reference voltage to 3.45 V.

[0111] After the reference voltage is updated to a smaller voltage value, the presence or absence of lithium deposition in the battery can be determined more strictly. Therefore, the battery management device 100 has an advantage in that it can more accurately diagnose the presence or absence of lithium deposition in the battery by appropriately updating the reference voltage.

[0112] The battery management device 100 according to the present invention is applicable to a battery management system (BMS). That is, the BMS according to the present invention may include the battery management device 100 described above. In this configuration, at least some of the components of the battery management device 100 may be realized by complementing or adding functions of components included in a conventional BMS. For example, the inflection point extraction unit 110, the control unit 120, and the storage unit 130 of the battery management device 100 may be realized as components of the BMS.

[0113] The battery management device 100 according to the present invention may be provided in a battery pack. That is, the battery pack according to the present invention may include the above-described battery management device 100 and one or more battery cells. The battery pack may further include electrical components (relays, fuses, etc.), a case, etc.

[0114] FIG. 8 is a diagram illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention.

[0115] The positive terminal of battery B may be connected to the positive terminal P+ of the battery pack 10, and the negative terminal of battery B may be connected to the negative terminal P− of the battery pack 10.

[0116] The measurement unit 200 may be connected to a first sensing line SL1, a second sensing line SL2, a third sensing line SL3, and a fourth sensing line SL4.

[0117] Specifically, the measurement unit 200 may be connected to a positive terminal of the battery B via a first sensing line SL1 and to a negative terminal of the battery B via a second sensing line SL2. The measurement unit 200 may measure the voltage of the battery B based on the voltages measured on the first sensing line SL1 and the second sensing line SL2.

[0118] The measurement unit 200 may be connected to the current measurement unit A via a third sensing line SL3. For example, the current measurement unit A may be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of the battery B. The measurement unit 200 may measure the charging current of the battery B via the third sensing line SL3 to calculate the amount of the charging current. The measurement unit 200 may also measure the discharging current of the battery B via the third sensing line SL3 to calculate the amount of the discharging current.

[0119] The measurement unit 200 is connected to the battery B via a fourth sensing line SL4, and can measure the temperature of the battery B during the charging process of the battery B.

[0120] The charging / discharging device 20 may be configured to be connected to the battery pack 10 to charge and / or discharge the battery B.

[0121] 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 the battery pack 10, the charging / discharging device 20, the negative terminal P- of the battery pack 10, and the negative terminal of battery B can be electrically connected to each other.

[0122] Meanwhile, the battery management device 100 according to the present invention may be provided in a server.

[0123] Specifically, the server may be directly and / or indirectly connected to the BMS connected to the battery via a wired or wireless network, for example, the server may be a cloud server.

[0124] The server may be directly connected to the BMS, or indirectly connected to the BMS via another device connected to the BMS. For example, a user terminal connected to the BMS may be connected to the server, or a charging device (e.g., a charger stand / station) connected to the BMS may be connected to the server.

[0125] The server may receive battery information (temperature, current, and voltage) and a battery profile (BP) from the BMS, and may diagnose whether or not lithium deposition has occurred in the battery based on the received battery information and battery profile (BP).

[0126] FIG. 9 is a diagram illustrating a battery management method according to still another embodiment of the present invention.

[0127] Preferably, each step in the battery management method may be performed by the battery management device 100. In the following, for ease of explanation, the contents overlapping with those described above will be omitted or will be described briefly.

[0128] Referring to FIG. 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 presence / absence diagnosis step (S400).

[0129] The inflection point extraction step (S100) is a step of extracting an inflection point from a battery profile (BP) that indicates a change in the voltage of a battery over time, and may be performed by the inflection point extraction unit 110.

[0130] For example, in the embodiment of FIG. 2, the inflection point extractor 110 may extract an inflection point from the CC section of the battery profile (BP).

[0131] The target information determining step (S200) is a step of determining a target voltage, a target temperature, and a target current amount of the battery corresponding to an inflection point, and may be performed by the control unit 120.

[0132] For example, in the course of charging and discharging the battery, not only the voltage of the battery but also the temperature and the amount of charging and discharging current may be measured, so that the control unit 120 can determine a target temperature and a target amount of current corresponding to the target voltage.

[0133] The reference voltage determination step (S300) is a step of determining a reference voltage corresponding to a target temperature and a target amount of current in a preset voltage table (VT), and can be performed by the control unit 120.

[0134] For example, the control unit 120 may first determine a reference temperature corresponding to a target temperature and a reference current amount corresponding to a target current amount in the voltage table (VT), and then determine a reference voltage corresponding to the reference temperature and the reference current amount in the voltage table (VT).

[0135] The lithium deposition diagnosis step (S400) is a step of diagnosing whether or not lithium is deposited in the battery based on a reference voltage and a target voltage, and may be performed by the control unit 120.

[0136] For example, the control unit 120 may calculate a voltage deviation between the reference voltage and the target voltage. If the voltage deviation is equal to or greater than a preset threshold voltage, the control unit 120 may be configured to diagnose that lithium has been deposited in the battery. Conversely, if the voltage deviation is less than the threshold voltage, the control unit 120 may be configured to diagnose that lithium has not been deposited in the battery. For example, the threshold voltage may be set to 10 mV.

[0137] The above-described embodiments of the present invention may be realized not only by an apparatus and a method, but also by a program for implementing functions corresponding to the configurations of the embodiments of the present invention or a recording medium having the program recorded thereon. Such implementation can be easily achieved by a person skilled in the technical field to which the present invention pertains, based on the description of the above-described embodiments.

[0138] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the equivalent scope of the technical concept of the present invention and the scope of the claims.

[0139] Furthermore, the present invention described above may be variously replaced, modified, and altered by a person having ordinary knowledge in the technical field to which the present invention belongs without departing from the technical spirit of the present invention, and therefore is not limited to the above-described embodiments and the accompanying drawings, and may be configured by selectively combining all or part of each embodiment for various modifications. [Explanation of symbols]

[0140] 10 Battery Pack 20 Charge / discharge device 100 Battery management device 110 Inflection point extraction part 120 Control section 130 Storage area 200 Measuring section

Claims

1. an inflection point extractor for extracting an inflection point from a battery profile indicating a change in the voltage of the battery over time; a control unit that determines a target voltage, a target temperature, and a target current amount of the battery corresponding to the inflection point, determines a reference voltage corresponding to the target temperature and the target current amount in a preset voltage table, and diagnoses whether or not lithium is precipitated in the battery based on the reference voltage and the target voltage; A battery management device comprising:

2. The control unit is The battery management device according to claim 1 , wherein the presence or absence of lithium deposition is diagnosed based on a voltage deviation between the reference voltage and the target voltage.

3. The control unit is If the voltage deviation is equal to or greater than a preset threshold voltage, it is determined that the lithium has been deposited in the battery; 3. The battery management device according to claim 2, wherein if the voltage deviation is less than the threshold voltage, it is diagnosed that the lithium is not deposited in the battery.

4. The control unit is determining a reference temperature corresponding to the target temperature; determining a reference current amount corresponding to the target current amount; The battery management device according to claim 1 , further comprising: a voltage table that determines the reference voltage corresponding to the reference temperature and the reference current amount.

5. The control unit is determining a temperature closest to the target temperature as the reference temperature among a plurality of predetermined temperatures; 5. The battery management device according to claim 4, wherein an amount of current closest to the target amount of current is determined as the reference amount of current from among a plurality of predetermined amounts of current.

6. The control unit is determining one or more reference temperatures from a plurality of predetermined temperatures that are within a predetermined temperature range from the target temperature; determining one or more reference current amounts that are within a predetermined current amount range from the target current amount among a plurality of predetermined current amounts; 5. The battery management device according to claim 4, wherein the reference voltage is determined to be a minimum voltage among one or more voltages resulting from combinations of the determined one or more reference temperatures and one or more reference current amounts.

7. The control unit is 5. The battery management device of claim 4, wherein when the predetermined plurality of temperatures does not have a value identical to the target temperature, or when the predetermined plurality of current amounts does not have a value identical to the target current amount, an interpolation method is used to determine the reference voltage corresponding to the target temperature and the target current amount in the voltage table.

8. The voltage table is 2. The battery management device according to claim 1, wherein the battery management device is a table in which the voltage of the battery corresponding to the temperature of the battery and the amount of current of the battery is recorded.

9. The battery profile includes:

2. The battery management device of claim 1, wherein the profile recorded indicates the voltage over charge or discharge time when the battery is charged or discharged at a constant current.

10. Further comprising a storage unit for storing the voltage table; The control unit is 2. The battery management device of claim 1, wherein the reference voltage corresponding to the target temperature and the target current amount is stored in advance in the voltage table stored in the storage unit, and when the target voltage is lower than the reference voltage, the reference voltage is updated to the target voltage.

11. A battery pack comprising the battery management device according to any one of claims 1 to 10.

12. A battery management server comprising the battery management device according to any one of claims 1 to 10.

13. An inflection point extraction step of extracting an inflection point from a battery profile showing a change in the voltage of the battery over time; a target information determination step of determining a target voltage, a target temperature, and a target current amount of the battery corresponding to the inflection point; a reference voltage determination step of determining a reference voltage corresponding to the target temperature and the target current amount in a preset voltage table; a lithium precipitation diagnosis step of diagnosing whether or not lithium is precipitated in the battery based on the reference voltage and the target voltage; How to manage the battery, including:

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