Battery diagnostic device and method

Abstract

A battery diagnostic device according to an embodiment of the present invention includes: a profile acquisition unit configured to acquire a differential profile indicating a correspondence relationship between a voltage of a battery and a differential capacity with respect to the voltage; and a control unit configured to determine a target peak from the differential profile, determine a first comparison result by comparing the voltage and the differential capacity between a reference peak of a preset reference profile for the battery and the determined target peak, and determine a state of the battery based on the first comparison result and the second comparison result.

Description

Technical Field

[0001] The present invention relates to a battery diagnostic apparatus and method, and more particularly, to a battery diagnostic apparatus and method for diagnosing the state of a battery in a non-destructive manner.

[0002] This application claims priority based on Korean Patent Application No. 10-2022-0143795 filed on November 1, 2022, and all the contents disclosed in the specification and drawings of the application are incorporated into this application.

Background Art

[0003] Recently, the demand for portable electronic products such as notebook PCs, video cameras, and mobile phones has increased rapidly, and as the development of electric vehicles, energy storage batteries, robots, satellites, etc. has become full-scale, research on high-performance batteries capable of repeated charging and discharging has been actively conducted.

[0004] Currently, commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium batteries, etc. Among these, lithium batteries have attracted attention because they hardly cause a memory effect compared to nickel-based batteries, can be freely charged and discharged, have a very low self-discharge rate, and have a high energy density.

[0005] Generally, a battery includes a positive electrode and a negative electrode and has the characteristic of deteriorating as it is used. And the degree of deterioration of the positive electrode and the negative electrode can vary due to various causes such as the usage environment and usage history of the battery.

[0006] Also, it is not easy to disassemble an operating battery, and accidents such as explosions may occur during the disassembly process. That is, it is practically impossible to directly check the states of the positive electrode and the negative electrode by disassembling the battery. Therefore, the development of a technique for diagnosing the state of a battery based on information related to the battery using a non-destructive method is required.

Summary of the Invention

[0007] This invention has been made in view of the above-mentioned problems, and aims to provide a battery diagnostic device and method that can diagnose the state of a battery in a non-destructive manner.

[0008] Other objects and advantages of the present invention can be understood from the following description and will be more clearly understood from the embodiments of the present invention. Furthermore, the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0009] A battery diagnostic device according to one aspect of the present invention may include: a profile acquisition unit configured to acquire a differential profile showing the correspondence between the voltage of a battery and the differential capacity with respect to the voltage; and a control unit configured to determine a target peak from the differential profile, determine a first comparison result by comparing the voltage between the determined target peak and a reference peak of a reference profile set in advance for the battery, and a second comparison result by comparing the differential capacity; and determine the state of the battery based on the first comparison result and the second comparison result.

[0010] The control unit may be configured to compare the magnitude of the voltage between the reference peak and the target peak and determine the first comparison result to determine a first state or a second state.

[0011] The control unit may be configured to compare the magnitude of the differential capacitance between the reference peak and the target peak and determine the second comparison result to determine the first state or the second state.

[0012] The control unit may be configured to determine the first comparison result as the first state if the voltage of the target peak exceeds the voltage of the reference peak.

[0013] The control unit may be configured to determine the first comparison result as the second state if the voltage of the target peak is less than the voltage of the reference peak.

[0014] The control unit may be configured to determine the second comparison result as the first state if the differential capacitance of the target peak exceeds the differential capacitance of the reference peak.

[0015] The control unit may be configured to determine the second comparison result as the second state if the differential capacitance of the target peak is less than the differential capacitance of the reference peak.

[0016] The control unit may be configured to determine the state of the positive electrode of the battery based on the first comparison result and the second comparison result.

[0017] The control unit may be configured to determine, based on the first comparison result, whether the state of the positive electrode of the battery is a first degraded state or a second degraded state, if the second comparison result is the second state.

[0018] The control unit may be configured to determine the state of the positive electrode of the battery as a first degraded state when the second comparison result is determined to be the second state and the first comparison result is determined to be the second state.

[0019] The control unit may be configured to determine the state of the positive electrode of the battery as a second degraded state when the second comparison result is determined to be the second state and the first comparison result is determined to be the first state.

[0020] The control unit may be configured to, when the positive electrode state is determined to be the second degraded state, reduce at least one of the upper limit of the charge / discharge C-rate and the upper limit of the available SOC that are set in advance for the battery, or to dispose of the battery as unusable.

[0021] 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.

[0022] A battery diagnostic method according to still another aspect of the present invention may include a differential profile acquisition step of acquiring a differential profile indicating a correspondence between a voltage of a battery and a differential capacitance with respect to the voltage, a target peak determination step of determining a target peak from the differential profile, a comparison result determination step of determining a first comparison result of comparing the voltage and a second comparison result of comparing the differential capacitance between a reference peak of a reference profile preset for the battery and the determined target peak, and a battery state determination step of determining a state of the battery based on the first comparison result and the second comparison result.

Advantages of the Invention

[0023] According to one aspect of the present invention, the battery diagnostic device has an advantage that it can diagnose the electrode state of a battery in consideration of peak behavior in the differential profile of the battery. That is, the battery diagnostic device has an advantage that it can diagnose the state of the battery more specifically in a non-destructive manner.

[0024] Also, according to one aspect of the present invention, the battery diagnostic device has an advantage that it can set usage conditions appropriate for the current state of the battery.

[0025] The effects of the present invention are not limited to the effects described above, and other effects of the present invention not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0026] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention. Therefore, the present invention should not be construed as being limited only to the matters described in the drawings.

Brief Description of the Drawings

[0027] [Figure 1]It is a diagram schematically showing a battery diagnostic device according to an embodiment of the present invention. [Figure 2] It is a diagram schematically showing a battery profile according to an embodiment of the present invention. [Figure 3] It is a diagram schematically showing a differential profile according to an embodiment of the present invention. [Figure 4] It is a diagram schematically showing a reference profile and a differential profile according to an embodiment of the present invention. [Figure 5] It is a diagram schematically showing a diagnostic table according to an embodiment of the present invention. [Figure 6] It is a diagram schematically showing an exemplary configuration of a battery pack according to another embodiment of the present invention. [Figure 7] It is a diagram schematically showing a battery diagnostic method according to still another embodiment of the present invention.

Mode for Carrying Out the Invention

[0028] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in this specification and the claims should not be construed as being limited to ordinary or dictionary meanings, and the inventors should interpret them in accordance with the meaning and concept corresponding to the technical idea of the present invention in accordance with the principle that they can appropriately define the concept of the terms in order to explain the invention in the best way.

[0029] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and there may be various equivalents and modifications that can replace them at the time of this application.

[0030] In addition, when a specific description of a known function or configuration related to the present invention is determined to obscure the gist of the present invention, the description thereof will be omitted.

[0031] Terms that include ordinal numbers, such as "first," "second," etc., are used to distinguish one of several components from the rest, and do not mean that such terms limit the components.

[0032] Furthermore, throughout the specification, when a part of it is stated that it "includes" a certain component, unless otherwise specified, this does not mean that other components are excluded, but rather that other components may be included.

[0033] Furthermore, when a part of the specification is described as being "connected" to another part, this includes not only cases where it is "directly connected," but also cases where it is "indirectly connected" through other elements in between.

[0034] Desired embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0035] Figure 1 is a schematic diagram of a battery diagnostic device 100 according to one embodiment of the present invention. Here, "battery" means a single, independent cell that has a negative terminal and a positive terminal and is physically separable. For example, a lithium-ion battery or a lithium polymer battery may be considered a battery. Alternatively, a battery may mean a battery module in which multiple cells are connected in series and / or parallel. For the sake of explanation, in the following, "battery" will be used to mean a single, independent cell.

[0036] Referring to Figure 1, a battery diagnostic device 100 according to one embodiment of the present invention may include a profile acquisition unit 110 and a control unit 120.

[0037] The profile acquisition unit 110 may be configured to acquire a differential profile that shows the correspondence between the battery voltage and the differential capacity with respect to the voltage.

[0038] Here, differential capacity is the value obtained by differentiating the battery capacity with respect to voltage, and can be expressed as dQ / dV. In other words, differential capacity can be expressed as the instantaneous rate of change of capacity with respect to voltage.

[0039] In one embodiment, the profile acquisition unit 110 can directly acquire a differential profile from an external source. For example, the profile acquisition unit 110 can acquire a differential profile by receiving a pre-generated differential profile.

[0040] In other embodiments, the profile acquisition unit 110 may be configured to acquire a battery profile from an external source that shows the correspondence between the battery voltage and capacity. The profile acquisition unit 110 can then acquire a differential profile by directly generating a differential profile from the battery profile.

[0041] In another embodiment, the profile acquisition unit 110 can acquire battery information, including the battery voltage and capacity. The profile acquisition unit 110 can then generate a battery profile showing the correspondence between voltage and capacity based on the battery information. Here, the battery voltage and capacity are measured by a measuring device, and the profile acquisition unit 110 can acquire the measured battery information. The profile acquisition unit 110 can directly generate a battery profile from the battery information.

[0042] The above describes a restrictive embodiment in which the profile acquisition unit 110 acquires a differential profile. However, the profile acquisition unit 110 can acquire a differential profile for the battery in a variety of ways other than the restricted embodiment described above.

[0043] Figure 2 is a schematic diagram showing a battery profile according to one embodiment of the present invention.

[0044] In the embodiment shown in Figure 2, the battery profile is a profile that shows the correspondence between the battery's capacity and voltage. The battery profile can be shown as an XY graph where X is set to capacity and Y is set to voltage. The positive electrode profile is the profile related to the positive electrode of the battery, and the negative electrode profile is the profile related to the negative electrode of the battery. Preferably, the profile acquisition unit 110 can acquire the battery profile shown in the embodiment of Figure 2. Depending on the embodiment, the profile acquisition unit 110 can also acquire both the positive electrode profile and the negative electrode profile.

[0045] Figure 3 is a schematic diagram showing a differential profile DP according to one embodiment of the present invention.

[0046] In the embodiment shown in Figure 3, the differential profile DP can be represented by an XY graph when X is set to voltage V and Y is set to differential capacitance dQ / dV.

[0047] The control unit 120 may be configured to determine the target peak from the differential profile DP.

[0048] Specifically, the differential profile DP may contain multiple peaks. Here, a peak can be a point in the differential profile DP where the slope is 0 and the shape bulges upward. In other words, a peak can be a point where the instantaneous rate of change of the differential capacitance with respect to voltage is 0, and the slope of the differential profile DP changes from positive to negative. In the embodiment shown in Figure 3, the differential profile DP may contain a first peak p1, a second peak p2, a third peak p3, a fourth peak p4, and a fifth peak p5.

[0049] The control unit 120 can determine the target peak from among the multiple peaks included in the differential profile DP that belong to a preset target voltage range VR. Here, the preset target voltage range VR may mean the uppermost voltage range in the overall voltage range of the battery. For example, in the case of a 4.2V battery, the target voltage range VR may be set to approximately 4V to 4.2V.

[0050] More specifically, the target voltage range VR can be pre-set to the voltage range in which the fifth peak p5 is shown. The fifth peak p5 is the peak shown in the differential profile DP of a nickel-containing battery. For example, the fifth peak p5 is the peak shown in the differential profile DP of a high-nickel battery with a nickel content of 70% or more. Typically, the target voltage range VR in which the fifth peak p5 is shown in the differential profile DP of a high-nickel battery is known to be the voltage range corresponding to the 80% to 100% range of the battery's SOC (State of Charge). That is, the voltage range corresponding to SOC 80% to 100% can be pre-set as the target voltage range VR. Therefore, the control unit 120 can determine the peak belonging to the pre-set target voltage range VR from among the multiple peaks included in the differential profile DP as the target peak.

[0051] In the embodiment shown in Figure 3, the control unit 120 may determine the fifth peak p5 as the target peak among the multiple peaks p1 to p5.

[0052] The control unit 120 may be configured to determine a first comparison result obtained by comparing the voltage between a reference peak of a preset reference profile for the battery and a determined target peak, and a second comparison result obtained by comparing the differential capacity.

[0053] Specifically, the reference profile is a profile that shows the correspondence between the voltage and differential capacity of a reference battery. Here, the reference battery may be a battery in the BOL (Beginning of Life) state, or an experimental battery corresponding to a battery in the BOL state. That is, the reference profile can be pre-set based on the voltage and capacity of the reference battery. Then, among the multiple peaks included in the reference profile, the peak that belongs to the target voltage interval VR can be determined as the reference peak.

[0054] Preferably, the control unit 120 may determine a first comparison result by comparing the magnitude of the voltage between the reference peak and the target peak, and determine a second comparison result by comparing the magnitude of the differential capacitance between the reference peak and the target peak.

[0055] Figure 4 is a schematic diagram showing the reference profile RP and differential profile DP according to one embodiment of the present invention.

[0056] For example, in the embodiment shown in Figure 4, assume that the reference profile RP includes a reference peak rp, and the differential profile DP includes a target peak tp. The reference peak rp has a voltage of Vr and a differential capacitance of Dr. The target peak tp has a voltage of Vt and a differential capacitance of Dt. The control unit 120 can determine a first comparison result by comparing the voltage Vr of the reference peak rp with the voltage Vt of the target peak tp. Then, the control unit 120 can determine a second comparison result by comparing the differential capacitance Dr of the reference peak rp with the differential capacitance Dt of the target peak tp.

[0057] In the embodiment shown in Figure 4, the control unit 120 may determine a first comparison result by considering that the voltage Vt of the target peak tp is smaller than the voltage Vr of the reference peak rp. Then, the control unit 120 may determine a second comparison result by considering that the differential capacitance Dt of the target peak tp is smaller than the differential capacitance Dr of the reference peak rp.

[0058] The control unit 120 may be configured to determine the state of the battery based on the first comparison result and the second comparison result.

[0059] Specifically, the control unit 120 can determine the state of the battery based on the combination of the first comparison result and the second comparison result. For example, the control unit 120 can diagnose the state of the battery's positive electrode based on the first comparison result and the second comparison result.

[0060] A battery diagnostic device 100 according to one embodiment of the present invention has the advantage of being able to diagnose the electrode state of a battery by considering the peak behavior in the differential profile DP of the battery. In other words, the battery diagnostic device 100 has the advantage of being able to diagnose the state of the battery more specifically by diagnosing the state of the positive electrode of the battery in a non-destructive manner.

[0061] On the other hand, the control unit 120 provided in the battery diagnostic device 100 may selectively include a processor, ASIC (application-specific integrated circuit), other chipsets, logic circuits, registers, communication modems, data processing devices, etc., known in the industry, in order to perform the various control logics performed in the present invention. Furthermore, when the control logic is embodied as software, the control unit 120 may be embodied as a collection of program modules. In this case, the program modules are stored in memory and can be executed by the control unit 120. The memory may be located inside or outside the control unit 120 and can be connected to the control unit 120 by various known means.

[0062] The battery diagnostic device 100 may further include a storage unit 130. The storage unit 130 may store data and programs necessary for each component of the battery diagnostic device 100 to operate and function, or data generated during the process of operation and functioning. The type of storage unit 130 is not particularly limited as long as it is a known information storage means capable of recording, erasing, updating, and reading data. Examples of information storage means include RAM, flash memory (registered trademark), ROM, EEPROM, and registers. The storage unit 130 may also store program code that defines processes executable by the control unit 120.

[0063] The following describes in detail an embodiment in which the control unit 120 determines the first comparison result and the second comparison result.

[0064] The control unit 120 may be configured to compare the magnitudes of the voltages of a reference peak rp and a target peak tp and determine the first comparison result to determine a first state or a second state.

[0065] Specifically, if the voltage of the target peak tp exceeds the voltage of the reference peak rp, the control unit 120 may determine the first comparison result to be the first state. Conversely, if the voltage of the target peak tp is less than the voltage of the reference peak rp, the control unit 120 may determine the first comparison result to be the second state.

[0066] In the embodiment shown in Figure 4, since the voltage Vt of the target peak tp is smaller than the voltage Vr of the reference peak rp, the control unit 120 can determine the first comparison result to be the second state.

[0067] The control unit 120 may be configured to compare the magnitude of the differential capacitance between a reference peak rp and a target peak tp and determine the first or second state based on the second comparison result.

[0068] Specifically, if the differential capacitance of the target peak tp exceeds the differential capacitance of the reference peak rp, the control unit 120 may determine the second comparison result to the first state. Conversely, if the differential capacitance of the target peak tp is less than the differential capacitance of the reference peak rp, the control unit 120 may determine the second comparison result to the second state.

[0069] In the embodiment shown in Figure 4, since the differential capacitance Dt of the target peak tp is smaller than the differential capacitance Dr of the reference peak rp, the control unit 120 can determine the second comparison result to be the second state.

[0070] In other words, in the first and second comparison results, the first state means that the current value exceeds the reference value, and the second state means that the current value is below the reference value.

[0071] Unlike the embodiment in Figure 4, if the voltage and differential capacitance of the target peak tp exceed the voltage and differential capacitance of the reference peak rp, both the first and second comparison results can be determined to the first state.

[0072] A battery diagnostic device 100 according to one embodiment of the present invention can independently determine the voltage comparison result (first comparison result) and the differential capacity comparison result (second comparison result) of the target peak tp and the reference peak rp. Since the battery state is diagnosed based on the first and second comparison results which are determined independently of each other, the reliability and accuracy of the state diagnosis result are increased.

[0073] The following describes in detail an embodiment in which the control unit 120 diagnoses the battery status based on the first and second comparison results.

[0074] Figure 5 is a schematic diagram showing a diagnostic table according to one embodiment of the present invention. Specifically, the diagnostic table in Figure 5 may be a table used to diagnose the state of the positive electrode of a battery based on a first comparison result and a second comparison result.

[0075] In the embodiment shown in Figure 5, if the second comparison result is determined to be the second state, the control unit 120 may be configured to determine the state of the battery's positive electrode. That is, if the differential capacity Dt of the target peak tp is less than the differential capacity Dr of the reference peak rp, the control unit 120 may determine the state of the battery's positive electrode based on the first comparison result. Specifically, if the second comparison result is the second state, the control unit 120 may be configured to determine the state of the battery's positive electrode as either the first or second degraded state based on the first comparison result.

[0076] For example, if the voltage Vt of the target peak tp is smaller than the voltage Vr of the reference peak rp (i.e., the first comparison result is the second state), the control unit 120 may diagnose the state of the positive electrode as the first degraded state.

[0077] Here, the first degradation state represents a state in which cracks occur between active material particles inside the battery, and may represent the normal degradation state of a battery (e.g., linear degradation).

[0078] In another example, if the voltage Vt of the target peak tp exceeds the voltage Vr of the reference peak rp (i.e., the first comparison result is the first state), the control unit 120 may diagnose the state of the positive electrode as the second degraded state.

[0079] Here, the second degradation state indicates a condition in which cracks occur inside the active material particles, potentially accelerating battery degradation. In such cases, there is a problem that gas generation inside the battery may increase sharply or a decrease in capacity may occur.

[0080] Therefore, the battery diagnostic device 100 can non-destructively and quickly diagnose the battery condition based on the differential capacity comparison result (second comparison result) and voltage comparison result (first comparison result) of the target peak tp and the reference peak rp.

[0081] The following describes an embodiment in which the control unit 120 controls the battery usage conditions based on the determined battery state.

[0082] Specifically, the control unit 120 can set usage conditions for the battery based on the state of the battery's positive electrode. Here, the initial usage conditions for the battery can be set in advance. The control unit 120 can then change the usage conditions according to the determined state of the positive electrode.

[0083] If the positive electrode state is determined to be the second degraded state, the control unit 120 may reduce at least one of the preset upper limits of the charge / discharge C-rate and the available SOC for the battery. In some embodiments, the control unit 120 may be configured to discard the battery.

[0084] For example, if the positive electrode of the battery is in a second degradation state, the control unit 120 may reduce the upper limit of the charge C-rate to prevent further degradation of the positive electrode. In other words, the control unit 120 may relax the conditions for rapid charging of the battery. As a result, rapid charging of the battery may be prevented, or the rapid charging level (e.g., rapid charging intensity) may be adjusted downwards.

[0085] In another example, if the state of the battery's positive electrode is in a second degraded state, the control unit 120 may reduce the upper limit of the available state of charge (SOC) to prevent further degradation of the positive electrode. That is, if the positive electrode is in a degraded state, the use of the positive electrode on its SOC side (i.e., the high potential side) may be restricted.

[0086] In another example, if the state of the battery's positive electrode is in a second-degree degradation state, the control unit 120 may be configured to discard the battery. That is, when the state of the battery's positive electrode is diagnosed as a second-degree degradation state, there is a problem that gas generation and / or capacity reduction may occur inside the battery due to cracks inside the active material particles. Internal gas generation can lead to battery venting, which can cause accidents such as fire and / or explosion. Therefore, the control unit 120 may be configured to discard the battery in order to prevent such accidents.

[0087] For example, in the embodiment shown in Figure 4, the control unit 120 can diagnose the state of the battery's positive electrode as a first degraded state. Therefore, the control unit 120 does not need to change the pre-set operating conditions for the battery.

[0088] A battery diagnostic device 100 according to one embodiment of the present invention has the advantage of being able to appropriately set the battery usage conditions based on the state of the positive electrode. Since appropriate usage conditions are set for the current state of the battery, further deterioration of the battery can be prevented or delayed. In other words, the battery diagnostic device 100 can improve the expected lifespan of the battery.

[0089] The battery diagnostic 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 may include the battery diagnostic device 100 described above. In such a configuration, at least some of the components of the battery diagnostic device 100 can be realized by complementing or adding to the functions of 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 diagnostic device 100 can be realized as components of a BMS.

[0090] Furthermore, the battery diagnostic 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 aforementioned battery diagnostic device 100 and one or more battery cells. The battery pack may further include electrical components (relays, fuses, etc.) and a case.

[0091] Figure 6 is a schematic diagram illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention.

[0092] The positive terminal of battery 10 may be connected to the positive terminal P+ of battery pack 1, and the negative terminal of battery 10 may be connected to the negative terminal P- of battery pack 1.

[0093] The measurement unit 20 can be connected to a first sensing line SL1, a second sensing line SL2, and a third sensing line SL3. Specifically, the measurement unit 20 can be connected to the positive terminal of the battery 10 via the first sensing line SL1 and to the negative terminal of the battery 10 via the second sensing line SL2. The measurement unit 20 can measure the voltage of the battery 10 based on the voltages measured from the first sensing line SL1 and the second sensing line SL2, respectively.

[0094] The measurement unit 20 may be connected to the current measurement unit A via the third sensing line SL3. For example, the current measurement unit A may be an ammeter or shunt resistor capable of measuring the charging current and discharging current of the battery 10. The measurement unit 20 may measure the charging current of the battery 10 via the third sensing line SL3 and calculate the charge amount. The measurement unit 20 may also measure the discharging current of the battery 10 via the third sensing line SL3 and calculate the discharge amount.

[0095] A charge / discharge device or load may be connected to the positive terminal P+ and negative terminal P- of the battery pack 1. The load may have one end connected to the positive terminal P+ of the battery pack 1 and the other end connected to the negative terminal P- of the battery pack 1. In this way, the positive terminal of the battery 10, the positive terminal P+ of the battery pack 1, the load, the negative terminal P- of the battery pack 1, and the negative terminal of the battery 10 can be electrically connected.

[0096] The profile acquisition unit 110 can acquire a battery profile by receiving voltage and capacity related to the battery 10 from the measurement unit 20. The profile acquisition unit 110 can then generate a differential profile DP from the acquired battery profile.

[0097] For example, battery information, including the voltage and capacity of the battery 10 measured by the measurement unit 20, can be stored in the storage unit 130. Battery profiles and differential profiles DP can also be stored in the storage unit 130.

[0098] Figure 7 is a schematic diagram illustrating a battery diagnostic method according to yet another embodiment of the present invention.

[0099] Preferably, each step of the battery diagnostic method may be performed by the battery diagnostic device 100. For the sake of clarity, any information that overlaps with what has been described above will be omitted or explained in a simplified manner below.

[0100] Referring to Figure 7, the battery diagnostic method may include a differential profile acquisition stage S100, a target peak determination stage S200, a comparison result determination stage S300, and a battery state determination stage S400.

[0101] The differential profile acquisition step S100 is a step in which a differential profile DP showing the correspondence between the battery voltage and the differential capacity with respect to the voltage is acquired, and can be performed by the profile acquisition unit 110.

[0102] For example, the profile acquisition unit 110 may directly receive the differential profile DP for the battery or generate it based on the battery profile.

[0103] The target peak determination step S200 is the step of determining the target peak tp from the differential profile DP, and can be performed by the control unit 120.

[0104] For example, the control unit 120 may determine the target peak tp as the peak belonging to the target voltage interval VR among the multiple peaks included in the differential profile DP.

[0105] In the embodiment shown in Figure 3, the control unit 120 can determine the fifth peak p5 as the target peak tp among the multiple peaks p1 to p5 included in the differential profile DP.

[0106] The comparison result determination step S300 is a step in which a first comparison result is determined by comparing the voltage of the reference peak rp of a preset reference profile RP for the battery with the determined target peak tp, and a second comparison result is determined by comparing the differential capacitance, and this step can be performed by the control unit 120.

[0107] The control unit 120 may determine a first comparison result by comparing the magnitudes of the voltage of the target peak tp and the voltage of the reference peak rp. Then, the control unit 120 may determine a second comparison result by comparing the magnitudes of the differential capacitance of the target peak tp and the differential capacitance of the reference peak rp.

[0108] For example, if the voltage of the target peak tp exceeds the voltage of the reference peak rp, the first comparison result may be determined to be the first state. Conversely, if the voltage of the target peak tp is less than the voltage of the reference peak rp, the first comparison result may be determined to be the second state.

[0109] In another example, if the differential capacity of the target peak tp exceeds the differential capacity of the reference peak rp, the second comparison result may be determined to the first state. Conversely, if the differential capacity of the target peak tp is less than the differential capacity of the reference peak rp, the second comparison result may be determined to the second state.

[0110] Here, the first state is when the current value (e.g., the value of the target peak tp) exceeds the reference value (e.g., the value of the reference peak rp), and the second state is when the current value is less than the reference value.

[0111] For example, in the embodiment shown in Figure 4, since the voltage Vt of the target peak tp is less than the voltage Vr of the reference peak rp, the first comparison result can be determined to be the second state. Furthermore, since the differential capacitance Dt of the target peak tp is less than the differential capacitance Dr of the reference peak rp, the second comparison result can be determined to be the second state.

[0112] Battery state determination step S400 is a step in which the state of the battery is determined based on the first comparison result and the second comparison result, and can be performed by the control unit 120.

[0113] Specifically, the control unit 120 can determine the state of the battery's positive electrode based on the first comparison result and the second comparison result.

[0114] Preferably, if the control unit 120 determines that the second comparison result is a second state, it may determine the state of the battery's positive electrode as either a first or second degraded state based on the first comparison result. That is, if the differential capacitance Dt of the target peak tp is less than the differential capacitance Dr of the reference peak rp, the control unit 120 may diagnose the state of the positive electrode by comparing the voltage Vt of the target peak tp with the voltage Vr of the reference peak rp.

[0115] For example, if the second comparison result is the second state and the first comparison result is the second state, the control unit 120 may determine that the state of the battery's positive electrode is the first degraded state. Conversely, if the second comparison result is the second state and the first comparison result is the first state, the control unit 120 may determine that the state of the battery's positive electrode is the second degraded state.

[0116] For example, in the embodiment shown in Figure 4, the first comparison result is the second state, and the second comparison result is the second state. From this, the control unit 120 can diagnose the state of the battery's positive electrode as the first degraded state.

[0117] In this embodiment, the control unit 120 can guide the battery to not degrade further by setting usage conditions for the battery based on the diagnosed results.

[0118] The embodiments of the present invention described above are not necessarily embodied through apparatus and methods, but can also be embodied through a program that realizes the functions corresponding to the configuration of the embodiments of the present invention, or through a recording medium on which such a program is recorded. Such embodiment should be easily realized by experts in the art to which the present invention belongs, based on the descriptions of the embodiments above.

[0119] Although the present invention has been described above with reference to limited embodiments and drawings, it goes without saying that the present invention is not limited thereto, and that various modifications and variations are possible within the equivalent scope of the technical concept and claims of the present invention by persons with ordinary skill in the art to which the present invention pertains.

[0120] Furthermore, since the present invention described above can be substituted, modified, and altered in various ways without departing from the technical concept of the invention by a person with ordinary skill in the art to which the invention belongs, it is not limited by the above-described embodiments and accompanying drawings, and can be constructed by selectively combining all or part of each embodiment to allow for various modifications. [Explanation of symbols]

[0121] 1 Battery Pack 10 batteries 100 Battery Diagnostic Device 110 Profile Acquisition Unit 120 Control Unit 130 Preservation Department

Claims

1. A profile acquisition unit configured to acquire a differential profile showing the correspondence between the battery voltage and the differential capacitance with respect to the said voltage, The control unit is configured to determine a target peak from the differential profile, compare the magnitude of the voltage between the determined target peak and a reference peak of a reference profile pre-set for the battery, determine a first comparison result as either a first state where the voltage of the target peak exceeds the voltage of the reference peak, or a second state where the voltage of the target peak is less than the voltage of the reference peak, compare the magnitude of the differential capacity between the determined target peak and a reference peak of a reference profile pre-set for the battery, determine a first comparison result as either a first state where the differential capacity of the target peak exceeds the differential capacity of the reference peak, or a second state where the differential capacity of the target peak is less than the differential capacity of the reference peak, and determine, based on the first and second comparison results, the state relating to the degradation rate of the positive electrode of the battery is either a first degradation state indicating linear degradation or a second degradation state indicating accelerated degradation of the battery. The control unit is configured to determine the target peak from among the multiple peaks included in the differential profile, the peak belonging to a target voltage interval that is set in advance to correspond to the uppermost voltage interval. The battery diagnostic device is characterized in that the control unit is configured to determine, based on the first comparison result, the state of the positive electrode of the battery as either a first degraded state or a second degraded state when the second comparison result is the second state.

2. The control unit, If the second comparison result determines the second state, and the first comparison result determines the second state, the state of the positive electrode of the battery is determined to be the first degraded state. The battery diagnostic device according to claim 1, characterized in that, when the second comparison result is determined to be the second state and the first comparison result is determined to be the first state, the state of the positive electrode of the battery is determined to be the second deterioration state.

3. The control unit, The battery diagnostic device according to claim 2, characterized in that, when the state of the positive electrode is determined to be the second degraded state, it is configured to reduce at least one of the upper limit of the charge / discharge C-rate and the upper limit of the available SOC that are set in advance for the battery, or to dispose of the battery as unusable.

4. A battery pack comprising a battery diagnostic device according to any one of claims 1 to 3.

5. A differential profile acquisition step is performed to obtain a differential profile that shows the correspondence between the battery voltage and the differential capacitance with respect to the said voltage, A target peak determination step in which the target peak is determined from the differential profile, A comparison result determination step in which the magnitude of the voltage is compared between the reference peak of a preset reference profile for the battery and the determined target peak, and the first comparison result is determined to be either a first state when the voltage of the target peak exceeds the voltage of the reference peak, or a second state when the voltage of the target peak is less than the voltage of the reference peak, and the magnitude of the differential capacity is compared between the reference peak of a preset reference profile for the battery and the determined target peak, and the second comparison result is determined to be either a first state when the differential capacity of the target peak exceeds the differential capacity of the reference peak, or a second state when the differential capacity of the target peak is less than the differential capacity of the reference peak, The process includes a battery state determination step in which, based on the first and second comparison results, the state of the degradation rate of the positive electrode of the battery is determined to be either a first degradation state indicating linear degradation or a second degradation state indicating accelerated degradation of the battery, The target peak determination step includes determining the target peak from among a plurality of peaks included in the differential profile, the peak belonging to a target voltage interval that is set in advance to correspond to the uppermost voltage interval, A battery diagnostic method characterized in that, if the battery state determination step is the second state, the step of determining the state of the positive electrode of the battery based on the first comparison result is the first degraded state or the second degraded state.

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