Apparatus and method for diagnosing battery

Abstract

An apparatus for diagnosing a battery, according to one embodiment of the present invention, comprises: a profile acquisition unit for acquiring a differential profile indicating a correspondence relationship between a voltage and a differential capacity of a battery; and a control unit, which determines a first target peak from among a plurality of peaks included in the differential profile, determines a voltage pattern of the first target peak on the basis of a voltage profile indicating a time series change of the first target peak, and diagnoses the state of the battery according to the determined voltage pattern.

Description

Battery diagnostic device and method

[0001] This application claims priority to Korean Patent Application No. 10-2024-0004175, filed on January 10, 2024, the entire contents of which are disclosed in the specification and drawings of the said application are incorporated herein by reference.

[0002] The present invention relates to a battery diagnosis device and method, and more particularly, to a battery diagnosis device and method for diagnosing the state of a battery by considering the peak behavior of a differential profile.

[0003] Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has rapidly increased, and the development of electric vehicles, energy storage batteries, robots, and satellites has been in full swing, research into high-performance batteries capable of repeated charging and discharging is actively being conducted.

[0004] Currently commercialized batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium batteries. Among these, lithium batteries are receiving attention for their advantages of being able to charge and discharge freely, having a very low self-discharge rate, and having a high energy density, as they have almost no memory effect compared to nickel-based batteries.

[0005] While extensive research is being conducted on these batteries to improve capacity and density, improving lifespan and safety is also crucial. To improve battery safety, technology is required to accurately diagnose the current battery condition.

[0006] The present invention has been devised to solve the above problems, and its purpose is to provide a battery diagnosis device and method for diagnosing the state of a battery in a non-destructive manner based on the peak behavior of a differential profile.

[0007] Other objects and advantages of the present invention can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0008] A battery diagnosis device according to one aspect of the present invention may include a profile acquisition unit configured to acquire a differential profile indicating a correspondence between a voltage and a differential capacity of a battery; and a control unit configured to determine a first target peak from among a plurality of peaks included in the differential profile, determine a voltage pattern of the first target peak based on a voltage profile indicating a time-series change in the voltage of the first target peak, and diagnose a state of the battery based on the determined voltage pattern.

[0009] The above control unit may be configured to determine the voltage pattern as a voltage decrease pattern, a voltage increase pattern, or a voltage maintenance pattern.

[0010] The control unit may be configured to determine the voltage pattern as the voltage reduction pattern if the voltage change rate of the first target peak in the voltage profile is less than a preset first reference value.

[0011] The control unit may be configured to determine the voltage pattern as the voltage increase pattern when the voltage change rate of the first target peak exceeds a preset second reference value.

[0012] The control unit may be configured to determine the voltage pattern as the voltage maintenance pattern if the voltage change rate of the first target peak is greater than or equal to the first reference value and less than or equal to the second reference value.

[0013] The control unit may be configured to diagnose the state of the battery as a capacity development state when the voltage pattern is determined as the voltage reduction pattern.

[0014] The control unit may be configured to diagnose the state of the battery as a state of available lithium loss when the voltage pattern is determined to be the voltage increase pattern.

[0015] The control unit may be configured to determine a second target peak from among a plurality of peaks included in the differential profile when the voltage pattern is determined as the voltage maintenance pattern, determine a differential capacity pattern of the second target peak based on a differential capacity profile representing a time-series change in the differential capacity of the second target peak, and diagnose the state of the battery based on the determined differential capacity pattern.

[0016] The above control unit may be configured to determine the differential capacity pattern as a differential capacity reduction pattern or a differential capacity non-reduction pattern.

[0017] The control unit may be configured to determine the differential capacity pattern as the differential capacity reduction pattern when the differential capacity change rate of the second target peak in the differential capacity profile is less than a preset third reference value.

[0018] The control unit may be configured to determine the differential capacity pattern as the differential capacity non-reduction pattern if the differential capacity change rate of the second target peak in the differential capacity profile is greater than or equal to the third reference value.

[0019] The control unit may be configured to diagnose the state of the battery as a positive electrode capacity loss state when the differential capacity pattern is determined as the differential capacity reduction pattern.

[0020] The control unit may be configured to diagnose the state of the battery as a maintenance state when the differential capacity pattern is determined as the differential capacity non-reduction pattern.

[0021] The control unit may be configured to divide the voltage profile into a plurality of sections based on the point in time at which the voltage pattern changes, and to diagnose the state of the battery for each of the plurality of sections.

[0022] A battery pack according to another aspect of the present invention may include a battery diagnostic device according to one aspect of the present invention.

[0023] A vehicle according to another aspect of the present invention may include a battery diagnostic device according to one aspect of the present invention.

[0024] A battery diagnosis method according to another aspect of the present invention may include a profile acquisition step of acquiring a differential profile indicating a correspondence between a voltage and a differential capacity of a battery; a target peak determination step of determining a first target peak from among a plurality of peaks included in the differential profile; a voltage pattern determination step of determining a voltage pattern of the first target peak based on a voltage profile indicating a time-series change of the first target peak; and a battery diagnosis step of diagnosing a state of the battery based on the determined voltage pattern.

[0025] According to one aspect of the present invention, a battery diagnostic device has the advantage of being able to diagnose the state of a battery in detail in a non-destructive manner by analyzing the behavior of peaks included in a differential profile.

[0026] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0027] The following drawings attached to this specification serve to further understand the technical idea of ​​the present invention together with the detailed description of the invention described below, and therefore the present invention should not be interpreted as being limited to the matters described in such drawings.

[0028] FIG. 1 is a schematic diagram illustrating a battery diagnostic device according to one embodiment of the present invention.

[0029] FIG. 2 is a schematic diagram illustrating a differential profile according to one embodiment of the present invention.

[0030] FIG. 3 is a diagram schematically illustrating a voltage profile according to one embodiment of the present invention.

[0031] FIG. 4 is a schematic diagram illustrating an embodiment in which a control unit according to one embodiment of the present invention diagnoses the status of a battery.

[0032] FIG. 5 is a schematic diagram illustrating a differential profile for a first battery according to one embodiment of the present invention.

[0033] FIG. 6 is a schematic diagram illustrating a differential profile for a second battery according to one embodiment of the present invention.

[0034] FIG. 7 is a schematic diagram illustrating a differential profile for a third battery according to one embodiment of the present invention.

[0035] FIG. 8 is a schematic drawing of a battery pack according to another embodiment of the present invention.

[0036] FIG. 9 is a schematic drawing of a vehicle according to another embodiment of the present invention.

[0037] FIG. 10 is a diagram schematically illustrating a battery diagnosis method according to another embodiment of the present invention.

[0038] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best possible manner.

[0039] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0040] In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0041] Terms that include ordinal numbers, such as first, second, etc., are used to distinguish one of the various components from the rest, and are not used to limit the components by such terms.

[0042] Throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

[0043] Additionally, throughout the specification, when we say that a part is "connected" to another part, this includes not only cases where it is "directly connected" but also cases where it is "indirectly connected" with other elements in between.

[0044]

[0045] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0046] FIG. 1 is a schematic diagram illustrating a battery diagnostic device (100) according to one embodiment of the present invention.

[0047] Referring to FIG. 1, the battery diagnostic device (100) may include a profile acquisition unit (110) and a control unit (120).

[0048] Here, a battery refers to a physically separate, independent cell having a negative terminal and a positive terminal. For example, a lithium-ion battery or a lithium polymer battery may be considered a battery. Furthermore, the battery may be of a cylindrical type, a prismatic type, or a pouch type. Furthermore, a battery may also refer to a battery bank, a battery module, or a battery pack in which multiple cells are connected in series and / or parallel. For convenience of explanation, the term "battery" will be described herein below as referring to a single, independent cell.

[0049] The profile acquisition unit (110) can be configured to acquire a differential profile (DP) indicating a correspondence between the differential capacity and voltage of the battery.

[0050] For example, a battery profile is a profile that represents the relationship between voltage (V) and capacity (Q) when the battery's SOC is charged from a preset start SOC or 0% to a preset end SOC or 100%. As another example, a battery profile may represent the relationship between voltage (V) and capacity (Q) when the battery's SOC is discharged from a preset start SOC or 100% to a preset end SOC or 0%.

[0051] And, when the battery profile is differentiated with respect to voltage, a differential profile (DP) can be generated that represents the correspondence between the differential capacity (dQ / dV) and the voltage (V).

[0052] For example, there are no specific restrictions on the C-rate for charging or discharging to generate a battery profile. However, to obtain more accurate battery profiles and differential profiles (DP), it is desirable to charge or discharge the battery at a low rate. For example, a battery profile can be generated during the process of charging or discharging the battery at 0.05C.

[0053] For example, the profile acquisition unit (110) can directly receive the differential profile (DP) of the battery from the outside. That is, the profile acquisition unit (110) can acquire the differential profile (DP) by being connected to the outside via wire and / or wirelessly and receiving the differential profile (DP).

[0054] As another example, the profile acquisition unit (110) can directly receive the battery profile of the battery from the outside. Furthermore, the profile acquisition unit (110) can differentiate the battery profile with respect to voltage to generate a differential profile (DP). That is, the profile acquisition unit (110) can be connected to the outside via wires and / or wirelessly to receive the battery profile and directly generate the differential profile (DP) from the battery profile, thereby acquiring the differential profile (DP).

[0055] As another example, the profile acquisition unit (110) may receive battery information regarding the voltage and capacity of the battery. Furthermore, the profile acquisition unit (110) may generate a battery profile based on the received battery information, and may generate a differential profile (DP) based on the generated battery profile. In other words, the profile acquisition unit (110) may directly generate the differential profile (DP) based on the battery information, thereby acquiring the differential profile (DP).

[0056] FIG. 2 is a schematic diagram illustrating a differential profile (DP) according to one embodiment of the present invention. Specifically, the differential profile (DP) can be expressed as an XY graph in which the X-axis is set to voltage and the Y-axis is set to differential capacitance.

[0057] The profile acquisition unit (110) may be connected to the control unit (120) so as to be able to communicate with it. For example, the profile acquisition unit (110) may be connected to the control unit (120) by wire and / or wirelessly. The profile acquisition unit may transmit the acquired differential profile (DP) to the control unit (120).

[0058] The control unit (120) may be configured to determine a first target peak (tp1) from among a plurality of peaks included in the differential profile (DP).

[0059] Specifically, a differential profile (DP) may include multiple peaks. Here, a peak is a point where the rate of change of the differential capacity with respect to voltage is zero, and the slope on the low-potential side (the rate of change of the differential capacity with respect to voltage) relative to the peak is positive, and the slope on the high-potential side is negative. Specifically, the peak corresponds to an inflection point of the battery profile and a maximum point of the differential profile (DP).

[0060] The control unit (120) can determine the peak with the lowest corresponding voltage among the plurality of peaks included in the differential profile (DP) as the first target peak (tp1).

[0061] For example, in the embodiment of FIG. 2, the differential profile (DP) may include a first peak (p1), a second peak (p2), a third peak (p3), and a fourth peak (p4). The control unit (120) may determine the first peak (p1) with the lowest corresponding voltage as the target peak.

[0062] The control unit (120) may be configured to determine the voltage pattern of the first target peak (tp1) based on a voltage profile (VP) representing a time-series change in the voltage of the first target peak (tp1).

[0063] Here, the time series change refers to the change of the first target peak (tp1) over time. For example, the profile acquisition unit (110) can acquire the first to n-th differential profiles (DP) for the battery. The control unit (120) can determine the first target peak (tp1) from each of the first to n-th differential profiles (DP). In addition, the control unit (120) can determine the voltage pattern of the first target peak (tp1) based on the time series change of the n first target peaks (tp1). Here, the time series change of the n first target peaks (tp1) can appear in the voltage profile (VP).

[0064] Preferably, the control unit (120) can include voltage information of the first target peak (tp1) determined from the differential profile (DP) in the voltage profile (VP). That is, the voltage profile (VP) can be updated every time the first target peak (tp1) is determined.

[0065] FIG. 3 is a schematic diagram illustrating a voltage profile (VP) according to one embodiment of the present invention. Specifically, the voltage profile (VP) can be expressed as an XY graph in which the X-axis is set as a cycle and the Y-axis is set as a voltage. Here, the X-axis can be applied without limitation as long as it is a value that can represent the time-series change of the first target peak (tp1).

[0066] The control unit (120) can determine the voltage pattern of the first target peak (tp1) based on the voltage change rate in the voltage profile (VP). Specifically, the control unit (120) can calculate the voltage change rate based on the instantaneous voltage change rate over time. In addition, the control unit (120) can determine the voltage pattern of the first target peak (tp1) based on the calculated voltage change rate.

[0067] For example, in the embodiment of FIG. 3, the control unit (120) can determine the voltage pattern of the first target peak (tp1) based on the instantaneous rate of change of voltage according to the cycle (i.e., the slope of the voltage profile (VP)). More specifically, the control unit (120) can determine the voltage increase / decrease pattern of the first target peak (tp1) based on the rate of change of voltage according to the cycle.

[0068] Specifically, the control unit (120) may be configured to determine the voltage pattern as a voltage decrease pattern, a voltage increase pattern, or a voltage maintenance pattern. The voltage decrease pattern is a pattern in which the voltage of the first target peak (tp1) gradually decreases as time elapses. The voltage increase pattern is a pattern in which the voltage of the first target peak (tp1) gradually increases as time elapses. The voltage maintenance pattern is a pattern in which the voltage of the first target peak (tp1) is maintained at a certain level even as time elapses.

[0069] Specifically, the data included in the voltage profile (VP) may be discontinuous. For example, in the embodiment of FIG. 3, the points indicated by "■" are discontinuous. Therefore, the control unit (120) may apply a regression model to the voltage profile (VP) to generate a regression profile in order to more accurately calculate the voltage change rate of the first target peak (tp1). Preferably, the control unit (120) may generate the regression profile using a polynomial regression model. For example, in the embodiment of FIG. 3, the regression profile indicated by the solid line is generated through the regression model. Since the regression profile is a continuous profile, the instantaneous voltage change rate for the cycle can be easily calculated.

[0070] If the voltage change rate of the first target peak (tp1) in the voltage profile (VP) is less than a preset first reference value, the control unit (120) may be configured to determine the voltage pattern as a voltage reduction pattern. Here, the first reference value may be preset to a value less than or equal to 0.

[0071] If the voltage change rate of the first target peak (tp1) exceeds a preset second reference value, the control unit (120) may be configured to determine the voltage pattern as a voltage increase pattern. Here, the second reference value may be preset to a value greater than or equal to 0. That is, the second reference value is equal to or greater than the first reference value.

[0072] If the voltage change rate of the first target peak (tp1) is greater than or equal to the first reference value and less than or equal to the second reference value, the control unit (120) may be configured to determine the voltage pattern as a voltage maintenance pattern.

[0073] For example, assume that the first reference value and the second reference value are equal to 0. If the voltage change rate is negative, the control unit (120) can determine the voltage pattern as a voltage decrease pattern. If the voltage change rate is positive, the control unit (120) can determine the voltage pattern as a voltage increase pattern. If the voltage change rate is 0, the control unit (120) can determine the voltage pattern as a voltage maintenance pattern.

[0074] As another example, the first reference value is r1, the second reference value is r2, and "r1<0 <r2"의 조건이 성립된다고 가정한다. 전압 변화율이 r1 미만이면, 제어부(120)는 전압 패턴을 전압 감소 패턴으로 결정할 수 있다. 전압 변화율이 r2를 초과하면, 제어부(120)는 전압 패턴을 전압 증가 패턴으로 결정할 수 있다. 전압 변화율이 r1 이상 r2 이하이면, 제어부(120)는 전압 패턴을 전압 유지 패턴으로 결정할 수 있다.

[0075] The control unit (120) can be configured to diagnose the status of the battery according to the determined voltage pattern.

[0076] Specifically, the battery status corresponding to each voltage pattern may differ from each other. Accordingly, the control unit (120) can specifically diagnose the battery status based on the voltage pattern of the first target peak (tp1).

[0077] For example, the state of a battery can be divided into a normal state and a fault state. The normal state includes a capacity development state, in which the battery's capacity is further developed, and a maintenance state, which represents a normal state in which the battery is not degraded. Furthermore, the fault state includes a cathode capacity loss state, in which the battery's cathode capacity is lost, and an available lithium loss state, in which the battery's available lithium is lost.

[0078] Here, the capacity development state refers to the state of the battery that can be exhibited depending on the positive electrode active material of the battery. For example, the capacity development state can be exhibited in a battery that contains an excess of lithium as the positive electrode active material. A representative example of a battery that contains an excess of lithium as the positive electrode active material is a battery that contains a lithium manganese oxide. Here, the lithium manganese oxide that contains an excess of lithium has a crystal structure that is a mixture of a layered phase (LiMO2) and a rock salt phase (Li2MnO3). During the charge / discharge process, the rock salt phase is activated, and the capacity is additionally developed due to the oxygen redox reaction, which can realize a high capacity. Specifically, since the oxygen redox reaction causes the manganese redox reaction, the battery capacity can be additionally developed.

[0079] Furthermore, anode capacity loss refers to a deterioration of a battery in which the usable capacity of the battery is reduced due to the loss of the battery's anode. Specifically, anode capacity loss refers to a state in which the usable anode area itself is reduced due to physical and / or chemical damage to the battery's anode.

[0080] In addition, available lithium loss refers to a deterioration pattern of a battery in which the usable lithium ions of the battery are reduced. Specifically, the available lithium loss state refers to a state in which lithium plating occurs on the surface of the negative electrode. When lithium is deposited on the surface of the negative electrode, it causes side reactions with the electrolyte and changes in the kinetic balance of the battery, which causes battery deterioration. In addition, since lithium metal deposited on the surface of the negative electrode can cause an internal short circuit in the battery, there is a risk of fire or explosion due to the internal short circuit.

[0081] Lastly, the maintenance state refers to the normal state in which the battery capacity is neither developed nor degraded.

[0082] A battery diagnostic device (100) according to one embodiment of the present invention has the advantage of being able to non-destructively diagnose and differentiate the state of a battery in detail by analyzing the behavior of peaks included in a differential profile (DP). In particular, the battery diagnostic device (100) can diagnose the state of a battery by determining the capacity development state, maintenance state, positive electrode capacity loss state, or available lithium loss state, thereby enabling more accurate identification of the current state of the battery.

[0083]

[0084] Meanwhile, the control unit (120) provided in the battery diagnostic device (100) may optionally include a processor, an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a register, a communication modem, a data processing device, etc. known in the art to execute various control logics performed in the present invention. In addition, when the control logic is implemented in software, the control unit (120) may be implemented as a set of program modules. At this time, the program modules may be stored in a memory and executed by the control unit (120). The memory may be located inside or outside the control unit (120) and may be connected to the control unit (120) by various well-known means.

[0085] In addition, the battery diagnostic device (100) may further include a storage unit (130). The storage unit (130) may store data or programs required for each component of the battery diagnostic device (100) to perform operations and functions, or data generated in the process of performing operations and functions. 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 recording, erasing, updating, and reading data. As an example, the information storage means may include RAM, flash memory, ROM, EEPROM, registers, etc. In addition, the storage unit (130) may store program codes defining processes executable by the control unit (120).

[0086]

[0087] Hereinafter, with reference to FIG. 4, an embodiment in which the control unit (120) diagnoses the status of the battery will be described in more detail.

[0088] FIG. 4 is a schematic diagram illustrating an embodiment in which a control unit (120) according to one embodiment of the present invention diagnoses the status of a battery.

[0089] In step S1, the control unit (120) can determine the voltage pattern of the first target peak (tp1). If the voltage pattern is determined to be a voltage decrease pattern, step S2 is performed, step S3 is performed in which the voltage pattern is determined to be a voltage increase pattern, and step S4 is performed in which the voltage pattern is determined to be a voltage maintenance pattern.

[0090] In step S2, the control unit (120) can diagnose the state of the battery as a capacity development state. That is, if the voltage pattern is determined to be a voltage reduction pattern, the control unit (120) can be configured to diagnose the state of the battery as a capacity development state.

[0091] In step S3, the control unit (120) can diagnose the state of the battery as a state of available lithium loss. That is, if the voltage pattern is determined to be a voltage increase pattern, the control unit (120) can be configured to diagnose the state of the battery as a state of available lithium loss.

[0092] Referring to FIG. 4, if the voltage pattern of the first target peak (tp1) is a voltage decrease pattern or a voltage increase pattern, the control unit (120) can immediately diagnose the state of the battery. However, if the voltage of the first target peak (tp1) is a voltage maintenance pattern, the control unit (120) can diagnose the state of the battery by further considering the second target peak (tp2).

[0093] In step S4, the control unit (120) may determine a differential capacity pattern of the second target peak (tp2). In step S4, if the differential capacity pattern is determined to be a differential capacity reduction pattern, step S5 is performed, and if the differential capacity pattern is determined to be a differential capacity non-reduction pattern, step S6 is performed. That is, if the voltage pattern is determined to be a voltage maintenance pattern, the control unit (120) may be configured to diagnose the state of the battery according to the determined differential capacity pattern.

[0094] Specifically, when the voltage pattern is determined as a voltage maintenance pattern, the control unit (120) may be configured to determine a second target peak (tp2) from among a plurality of peaks included in the differential profile (DP). The second target peak (tp2) is a peak with the largest corresponding differential capacity among the plurality of peaks included in the differential profile (DP). For example, in the embodiment of FIG. 2, the second peak (p2) may be determined as the second target peak (tp2).

[0095] The control unit (120) may be configured to determine a differential capacity pattern of the second target peak (tp2) based on a differential capacity profile representing a time-series change in the differential capacity of the second target peak (tp2). For example, in the embodiment of FIG. 3, a profile in which the voltage of the first target peak (tp1) is replaced by the differential capacity of the second target peak (tp2) is a differential capacity profile. That is, the differential capacity profile may be expressed as an XY graph in which the X-axis is set as a cycle and the Y-axis is set as the differential capacity. Here, the X-axis may be applied without limitation as long as it has a value that can represent a time-series change of the second target peak (tp2).

[0096] The control unit (120) may be configured to determine the differential capacity pattern as a differential capacity decreasing pattern or a differential capacity non-decreasing pattern. Here, the differential capacity non-decreasing pattern means a pattern in which the differential capacity increases or is maintained.

[0097] If the differential capacity change rate of the second target peak (tp2) in the differential capacity profile is less than a preset third reference value, the control unit (120) may be configured to determine the differential capacity pattern as a differential capacity reduction pattern. Conversely, if the differential capacity change rate of the second target peak (tp2) in the differential capacity profile is greater than or equal to the third reference value, the control unit (120) may be configured to determine the differential capacity pattern as a differential capacity non-reduction pattern.

[0098] Preferably, the third reference value may be set to a value less than or equal to 0. The third reference value may be set to an appropriate value that can distinguish the differential capacity pattern of the second target peak (tp2) into a differential capacity reduction pattern and a non-reduction pattern based on experimental or theoretically calculated results.

[0099] For example, assume that the third reference value is set to 0. If the differential capacity change rate is negative, the control unit (120) can determine the differential capacity pattern as a differential capacity reduction pattern. Conversely, if the differential capacity change rate is 0 or positive, the control unit (120) can determine the differential capacity pattern as a differential capacity non-reduction pattern.

[0100] As another example, assume that the third reference value is set to r3 and the condition "r3<0" is satisfied. If the differential capacity change rate is less than r3, the control unit (120) can determine the differential capacity pattern as a differential capacity reduction pattern. Conversely, if the differential capacity change rate is greater than or equal to r3, the control unit (120) can determine the differential capacity pattern as a differential capacity non-reduction pattern.

[0101] As in the embodiment of FIG. 3, the control unit (120) may apply a regression model to the differential capacity profile to generate a regression profile in order to more accurately calculate the differential capacity change rate of the second target peak (tp2). In addition, the control unit (120) may calculate the instantaneous change rate for the differential capacity of the second target peak (tp2), thereby calculating the differential capacity change rate. In addition, the control unit (120) may compare the calculated differential capacity change rate with a preset third reference value, thereby determining the differential capacity pattern as a differential capacity reduction pattern or a differential capacity non-reduction pattern.

[0102] In step S5, the control unit (120) can diagnose the state of the battery as a positive electrode capacity loss state. That is, if the differential capacity pattern is determined to be a differential capacity decrease pattern, the control unit (120) can be configured to diagnose the state of the battery as a positive electrode capacity loss state.

[0103] In step S6, the control unit (120) can diagnose the state of the battery as a maintenance state. That is, if the differential capacity pattern is determined to be a differential capacity non-reduction pattern, the control unit (120) can be configured to diagnose the state of the battery as a maintenance state.

[0104] A battery diagnostic device (100) according to one embodiment of the present invention can diagnose the state of a battery in detail based on the voltage pattern of a first target peak (tp1) and the differential capacity pattern of a second target peak (tp2). Therefore, the battery diagnostic device (100) has the advantage of being able to diagnose the current state of a battery more accurately and in detail.

[0105]

[0106] FIG. 5 is a schematic diagram illustrating differential profiles (DP1, DP2) for a first battery according to an embodiment of the present invention. Specifically, in the embodiment of FIG. 5, the first differential profile (DP1) is a differential profile of the beginning of life (BOL) state of the first battery, and the second differential profile (DP2) is a differential profile of the middle of life (MOL) state of the first battery. That is, in terms of timing, the first differential profile (DP1) precedes, and the second differential profile (DP2) follows.

[0107] Specifically, the first battery is a battery in a capacity development state. That is, the first battery is in a state where additional capacity is developed through a redox reaction.

[0108] Referring to FIG. 5, the voltage of the first target peak (tp21) of the second differential profile (DP2) is lower than the voltage of the first target peak (tp11) of the first differential profile (DP1). That is, in the capacity development state, the voltage of the first target peak (tp21) may shift toward the low potential side. Accordingly, if the voltage pattern of the first target peak (tp21) is a voltage decrease pattern, the control unit (120) can diagnose the state of the battery as the capacity development state.

[0109]

[0110] FIG. 6 is a schematic diagram illustrating differential profiles (DP1, DP3) for a second battery according to an embodiment of the present invention. Specifically, in the embodiment of FIG. 6, the first differential profile (DP1) is a differential profile of the BOL state of the second battery, and the third differential profile (DP3) is a differential profile of the MOL state of the second battery. That is, in terms of timing, the first differential profile (DP1) precedes and the third differential profile (DP3) follows.

[0111] Specifically, the second battery is a battery in a state of available lithium loss. That is, lithium metal has been deposited on the negative electrode surface of the second battery, reducing the amount of lithium available for charging and discharging.

[0112] Referring to FIG. 6, the voltage of the first target peak (tp31) of the third differential profile (DP3) is higher than the voltage of the first target peak (tp11) of the first differential profile (DP1). That is, in a state of available lithium loss, the voltage of the first target peak (tp31) may shift toward a high potential. Accordingly, if the voltage pattern of the first target peak (tp31) is a voltage increase pattern, the control unit (120) can diagnose the state of the battery as a capacity development state.

[0113]

[0114] FIG. 7 is a schematic diagram illustrating differential profiles (DP1, DP4) for a third battery according to one embodiment of the present invention. Specifically, in the embodiment of FIG. 7, the first differential profile (DP1) is a differential profile of the BOL state of the third battery, and the fourth differential profile (DP4) is a differential profile of the MOL state of the third battery. That is, in terms of timing, the first differential profile (DP1) precedes and the fourth differential profile (DP4) follows.

[0115] Specifically, the third battery is a battery in a state of positive electrode capacity loss. That is, the third battery has lost the area of ​​the positive electrode available for charging and discharging, resulting in a reduced positive electrode capacity.

[0116] Referring to FIG. 7, the voltage of the first target peak (tp41) of the fourth differential profile (DP4) matches the voltage of the first target peak (tp11) of the first differential profile (DP1). In addition, the differential capacity of the second target peak (tp42) of the fourth differential profile (DP4) is lower than the differential capacity of the second target peak (tp12) of the first differential profile (DP1). That is, in the positive electrode capacity loss state, the change in the voltage of the first target peaks (tp11, tp41) is minimal, but the differential capacity of the second target peaks (tp12, tp42) may decrease to a certain level or more. Therefore, the control unit (120) can diagnose the state of the battery as a positive electrode capacity loss state if the voltage pattern of the first target peak (tp41) is a voltage maintenance pattern and the differential capacity pattern of the second target peak (tp42) is a differential capacity decrease pattern.

[0117]

[0118] The control unit (120) can be configured to divide the voltage profile (VP) into multiple sections based on the point in time when the voltage pattern changes.

[0119] Specifically, the control unit (120) can divide the cycle section of the voltage profile (VP) into multiple sections. Preferably, the control unit (120) can divide the voltage profile (VP) into multiple sections based on the point in time when the voltage pattern changes.

[0120] For example, a voltage profile (VP) can be divided into multiple intervals based on when the voltage pattern changes from a voltage decreasing pattern to a voltage increasing pattern or a voltage holding pattern.

[0121] As another example, a voltage profile (VP) can be divided into multiple intervals based on when the voltage pattern changes from a voltage increasing pattern to a voltage decreasing pattern or a voltage holding pattern.

[0122] As another example, a voltage profile (VP) can be divided into multiple intervals based on when the voltage pattern changes from a voltage holding pattern to a voltage decreasing pattern or a voltage increasing pattern.

[0123] In the embodiment of FIG. 3, the control unit (120) can distinguish the voltage profile (VP) based on the 35th cycle. The first to 35th cycles are included in the first section (R1), and the 36th to 100th cycles are included in the second section (R2).

[0124] The control unit (120) may be configured to diagnose the status of the battery for each of a plurality of sections.

[0125] Specifically, since each of the plurality of sections has the same voltage pattern, the control unit (120) can diagnose the condition of the battery for each section.

[0126] For example, in the embodiment of FIG. 3, the voltage pattern corresponding to the first section (R1) is a voltage reduction pattern. Accordingly, the control unit (120) can diagnose the state of the battery as a capacity development state in the first to 35th cycles.

[0127] As another example, in the embodiment of FIG. 3, the voltage pattern corresponding to the second section (R2) is a voltage increase pattern. Accordingly, the control unit (120) can diagnose the battery's condition as a state of available lithium loss in the 36th to 100th cycles.

[0128] As another example, if the voltage pattern of a certain section is a voltage maintenance pattern, the control unit (120) can diagnose the state of the battery as a positive electrode capacity loss state or a maintenance state by considering the differential capacity pattern of the second target peak (tp2) in the section.

[0129] The battery diagnostic device (100) according to one embodiment of the present invention has the advantage of being able to track and diagnose the state of a battery. Therefore, since the battery diagnostic device (100) can identify the point in time when the battery's state changes, appropriate measures, such as charge / discharge control or changes in usage conditions, can be taken based on the battery's state change history.

[0130]

[0131] The battery diagnosis device (100) according to the present invention can be applied to a BMS (Battery Management System). That is, the BMS according to the present invention can include the battery diagnosis device (100) described above. In this configuration, at least some of the components of the battery diagnosis device (100) can be implemented by supplementing or adding to the functions of the components included in a conventional BMS. For example, the profile acquisition unit (110), the control unit (120), and the storage unit (130) of the battery diagnosis device (100) can be implemented as components of the BMS.

[0132] In addition, the battery diagnostic device (100) according to the present invention may be installed in a battery pack. That is, the battery pack according to the present invention may include the battery diagnostic device (100) described above and one or more battery cells. In addition, the battery pack may further include electrical components (relays, fuses, etc.) and a case, etc.

[0133] Figure 8 is a schematic drawing of a battery pack (1) according to another embodiment of the present invention.

[0134] The positive terminal of the battery (10) can be connected to the positive terminal (P+) of the battery pack (1), and the negative terminal of the battery (10) can be connected to the negative terminal (P-) of the battery pack (1).

[0135] The measuring unit (20) can be connected to a first sensing line (SL1), a second sensing line (SL2), and a third sensing line (SL3). Specifically, the measuring unit (20) can be connected to a positive terminal of the battery (10) through the first sensing line (SL1), and can be connected to a negative terminal of the battery (10) through the second sensing line (SL2). The measuring unit (20) can measure the voltage of the battery (10) based on the voltage measured at each of the first sensing line (SL1) and the second sensing line (SL2).

[0136] And, the measuring unit (20) can be connected to the current measuring unit (A) through the third sensing line (SL3). For example, the current measuring unit (A) can be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of the battery (10). The measuring unit (20) can measure the charging current of the battery (10) through the third sensing line (SL3) to calculate the charging amount. In addition, the measuring unit (20) can measure the discharging current of the battery (10) through the third sensing line (SL3) to calculate the discharging amount.

[0137] For example, the measuring unit (20) can transmit battery information regarding the voltage and current of the battery (10) to the battery diagnosis device (100). The profile acquisition unit (110) can receive battery information from the measuring unit (20) and generate a battery profile and a differential profile.

[0138] As another example, the measuring unit (20) can generate a battery profile indicating a correspondence between the voltage and capacity of the battery (10) and transmit the generated battery profile to the battery diagnosis device (100). The profile acquisition unit (110) can receive the battery profile from the measuring unit (20) and generate a differential profile based on the received battery profile.

[0139] As another example, the measuring unit (20) can generate a differential profile based on battery information and transmit the generated differential profile to the battery diagnostic device (100). The profile acquisition unit (110) can receive the differential profile from the measuring unit (20).

[0140] An external device can be connected to the positive terminal (P+) and negative terminal (P-) of the battery pack (1). For example, the external device can be a charging device or a load. In addition, the positive terminal of the battery (10), the positive terminal (P+) of the battery pack (1), the external device, the negative terminal (P-) of the battery pack (1), and the negative terminal of the battery (10) can be electrically connected.

[0141]

[0142] FIG. 9 is a schematic drawing of a vehicle (900) according to another embodiment of the present invention.

[0143] Referring to FIG. 9, a battery pack according to an embodiment of the present invention may be included in a vehicle (900), such as an electric vehicle (EV) or a hybrid vehicle (HV). Furthermore, the battery pack (910) may drive the vehicle (900) by supplying power to a motor through an inverter provided in the vehicle (900). Here, the battery pack (910) may include a battery diagnostic device (100). That is, the vehicle (900) may include a battery diagnostic device (100). In this case, the battery diagnostic device (100) may be an onboard device included in the vehicle (900).

[0144]

[0145] FIG. 10 is a diagram schematically illustrating a battery management method according to another embodiment of the present invention.

[0146] Referring to FIG. 10, the battery management method may include a profile acquisition step (S100), a target peak determination step (S200), a voltage pattern determination step (S300), and a battery diagnosis step (S400).

[0147] Preferably, each step of the battery management method can be performed by a battery diagnostic device (100). In the following, for convenience of explanation, any content that overlaps with the previously described content will be omitted or briefly described.

[0148] The profile acquisition step (S100) is a step of acquiring a differential profile (DP) indicating a correspondence between the voltage and differential capacity of the battery, and can be performed by the profile acquisition unit (110).

[0149] For example, the profile acquisition unit (110) can directly receive the differential profile (DP) of the battery from the outside. That is, the profile acquisition unit (110) can acquire the differential profile (DP) by being connected to the outside via wire and / or wirelessly and receiving the differential profile (DP).

[0150] As another example, the profile acquisition unit (110) can directly receive the battery profile of the battery from the outside. Furthermore, the profile acquisition unit (110) can differentiate the battery profile with respect to voltage to generate a differential profile (DP). That is, the profile acquisition unit (110) can be connected to the outside via wires and / or wirelessly to receive the battery profile and directly generate the differential profile (DP) from the battery profile, thereby acquiring the differential profile (DP).

[0151] As another example, the profile acquisition unit (110) may receive battery information regarding the voltage and capacity of the battery. Furthermore, the profile acquisition unit (110) may generate a battery profile based on the received battery information, and may generate a differential profile (DP) based on the generated battery profile. In other words, the profile acquisition unit (110) may directly generate the differential profile (DP) based on the battery information, thereby acquiring the differential profile (DP).

[0152] The target peak determination step (S200) is a step of determining a first target peak (tp1) among a plurality of peaks included in a differential profile (DP), and can be performed by the control unit (120).

[0153] The control unit (120) can determine the peak with the lowest corresponding voltage among the plurality of peaks included in the differential profile (DP) as the first target peak (tp1).

[0154] The voltage pattern determination step (S300) is a step of determining the voltage pattern of the first target peak (tp1) based on a voltage profile (VP) representing a time series change of the first target peak (tp1), and can be performed by the control unit (120).

[0155] Specifically, the control unit (120) can be configured to determine the voltage pattern as a voltage decrease pattern, a voltage increase pattern, or a voltage maintenance pattern.

[0156] If the voltage change rate of the first target peak (tp1) in the voltage profile (VP) is less than a preset first reference value, the control unit (120) may be configured to determine the voltage pattern as a voltage reduction pattern. Here, the first reference value may be preset to a value less than or equal to 0.

[0157] If the voltage change rate of the first target peak (tp1) exceeds a preset second reference value, the control unit (120) may be configured to determine the voltage pattern as a voltage increase pattern. Here, the second reference value may be preset to a value greater than or equal to 0. That is, the second reference value is equal to or greater than the first reference value.

[0158] If the voltage change rate of the first target peak (tp1) is greater than or equal to the first reference value and less than or equal to the second reference value, the control unit (120) may be configured to determine the voltage pattern as a voltage maintenance pattern.

[0159] Here, the first reference value and the second reference value can be set to appropriate values ​​that can distinguish the voltage pattern of the first target peak (tp1) into a voltage decrease pattern, a voltage increase pattern, or a voltage maintenance pattern based on experimentally or theoretically calculated results.

[0160] The battery diagnosis step (S400) is a step for diagnosing the status of the battery according to the determined voltage pattern, and can be performed by the control unit (120).

[0161] Referring to FIG. 4, if the voltage pattern of the first target peak (tp1) is a voltage decrease pattern or a voltage increase pattern, the control unit (120) can immediately diagnose the state of the battery. However, if the voltage of the first target peak (tp1) is a voltage maintenance pattern, the control unit (120) can diagnose the state of the battery by further considering the second target peak (tp2).

[0162] For example, if the voltage pattern is determined as a voltage reduction pattern, the control unit (120) may be configured to diagnose the state of the battery as a capacity expression state.

[0163] As another example, if the voltage pattern is determined to be a voltage increase pattern, the control unit (120) may be configured to diagnose the state of the battery as a state of available lithium loss.

[0164] As another example, if the voltage pattern is determined as a voltage maintenance pattern and the differential capacity pattern is determined as a differential capacity decrease pattern, the control unit (120) may be configured to diagnose the state of the battery as a positive electrode capacity loss state.

[0165] As another example, if the voltage pattern is determined as a voltage maintenance pattern and the differential capacity pattern is determined as a differential capacity non-reduction pattern, the control unit (120) may be configured to diagnose the state of the battery as a maintenance state.

[0166]

[0167] The embodiments of the present invention described above are not implemented only through devices and methods, but may also be implemented through a program that realizes a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded, and such implementation can be easily implemented by an expert in the technical field to which the present invention belongs based on the description of the embodiments described above.

[0168] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0169] In addition, the present invention described above is not limited to the above-described embodiments and the attached drawings, and all or part of each embodiment may be selectively combined and configured so that various modifications can be made, as those skilled in the art can make various substitutions, modifications, and changes within the scope of the technical idea of ​​the present invention.

[0170] (Explanation of symbols)

[0171] 1: Battery pack

[0172] 10: Battery

[0173] 20: Measurement section

[0174] 100: Battery Diagnostic Device

[0175] 110: Profile acquisition section

[0176] 120: Control unit

[0177] 130: Storage

[0178] 900: Car

[0179] 910: Battery Pack

Claims

1. A profile acquisition unit configured to acquire a differential profile indicating a correspondence between the voltage and differential capacity of the battery; and A battery diagnosis device characterized by including a control unit configured to determine a first target peak from among a plurality of peaks included in the differential profile, determine a voltage pattern of the first target peak based on a voltage profile representing a time-series change in voltage of the first target peak, and diagnose a state of the battery according to the determined voltage pattern.

2. In paragraph 1, The above control unit, A battery diagnostic device characterized in that it is configured to determine the voltage pattern as a voltage decrease pattern, a voltage increase pattern, or a voltage maintenance pattern.

3. In paragraph 2, The above control unit, If the voltage change rate of the first target peak in the above voltage profile is less than the preset first reference value, the voltage pattern is determined as the voltage reduction pattern, If the voltage change rate of the first target peak exceeds a preset second reference value, the voltage pattern is determined as the voltage increase pattern, A battery diagnostic device characterized in that it is configured to determine the voltage pattern as the voltage maintenance pattern if the voltage change rate of the first target peak is greater than or equal to the first reference value and less than or equal to the second reference value.

4. In paragraph 2, The above control unit, A battery diagnosis device characterized in that it is configured to diagnose the state of the battery as a capacity expression state when the voltage pattern is determined as the voltage reduction pattern.

5. In paragraph 2, The above control unit, A battery diagnostic device characterized in that it is configured to diagnose the state of the battery as an available lithium loss state when the voltage pattern is determined as the voltage increase pattern.

6. In paragraph 2, The above control unit, A battery diagnosis device characterized in that, when the voltage pattern is determined as the voltage maintenance pattern, a second target peak is determined from among a plurality of peaks included in the differential profile, a differential capacity pattern of the second target peak is determined based on a differential capacity profile representing a time-series change in the differential capacity of the second target peak, and a state of the battery is diagnosed based on the determined differential capacity pattern.

7. In paragraph 6, The above control unit, A battery diagnostic device characterized in that it is configured to determine the differential capacity pattern as a differential capacity decreasing pattern or a differential capacity non-decreasing pattern.

8. In paragraph 7, The above control unit, If the differential capacity change rate of the second target peak in the differential capacity profile is less than a preset third reference value, the differential capacity pattern is determined as the differential capacity reduction pattern, A battery diagnostic device characterized in that it is configured to determine the differential capacity pattern as the differential capacity non-decrease pattern if the differential capacity change rate of the second target peak in the differential capacity profile is greater than or equal to the third reference value.

9. In paragraph 7, The above control unit, A battery diagnostic device characterized in that it is configured to diagnose the state of the battery as a positive electrode capacity loss state when the above differential capacity pattern is determined as the above differential capacity reduction pattern.

10. In paragraph 7, The above control unit, A battery diagnosis device characterized in that it is configured to diagnose the state of the battery as a maintenance state when the above differential capacity pattern is determined as the above differential capacity non-reduction pattern.

11. In paragraph 2, The above control unit, A battery diagnostic device characterized in that it divides the voltage profile into a plurality of sections based on the time at which the voltage pattern changes, and is configured to diagnose the state of the battery for each of the plurality of sections.

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

13. A vehicle including a battery diagnostic device according to any one of claims 1 to 11.

14. A profile acquisition step for acquiring a differential profile representing the corresponding relationship between the voltage and differential capacity of the battery; A target peak determination step of determining a first target peak from among a plurality of peaks included in the above differential profile; A voltage pattern determination step for determining a voltage pattern of the first target peak based on a voltage profile representing a time series change of the first target peak; and A battery diagnosis method, characterized by including a battery diagnosis step of diagnosing the state of the battery according to a determined voltage pattern.

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