Apparatus and method for diagnosing state of battery, battery pack

Abstract

An apparatus for diagnosing a state of a battery according to one embodiment of the present application includes a curve acquisition unit configured to acquire a plurality of differential curves indicating a correspondence between a differential capacity and a voltage of the battery, the differential capacity indicating a rate of change of a capacity of the battery with respect to the voltage; a peak determination unit configured to determine a target peak value located in a predetermined voltage section in each of the plurality of differential curves; and a state diagnosis unit configured to compare a voltage of the plurality of target peak values determined by the peak determination unit with a voltage of a reference peak value preset corresponding to each of the plurality of target peak values, and diagnose the state of the battery based on a result of comparing the voltages.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2021-0022771, filed in Korea on February 19, 2021, the disclosure of which is incorporated herein by reference.

[0002] This disclosure relates to apparatus and methods for diagnosing the state of a battery, and more specifically, to apparatus and methods for diagnosing the state of a battery. Background Technology

[0003] Recently, demand for portable electronic products such as laptops, cameras, and mobile phones has increased dramatically, and electric vehicles, energy storage batteries, robots, and satellites have seen significant development. Therefore, research is actively underway on high-performance batteries that allow for repeated charging and discharging.

[0004] Currently available batteries include nickel-cadmium (NiCd), nickel-metal hydride (NiMH), nickel-zinc (NiZn), and lithium-ion batteries. Among them, lithium-ion batteries are particularly noteworthy because they exhibit almost no memory effect compared to nickel-based batteries, along with extremely low self-discharge rates and high energy density.

[0005] Typically, these batteries can degrade with repeated charge-discharge cycles. For example, at the positive electrode, the battery may degrade due to electrolyte oxidation or disruption of the crystal structure. Additionally, at the negative electrode, the battery may degrade due to lithium metal deposition. Therefore, there is a need to develop technologies that can non-destructively diagnose the state of batteries based on their voltage and capacity parameters. Summary of the Invention

[0006] Technical issues

[0007] This disclosure aims to address the problems in the related technologies, and therefore aims to provide an apparatus and method for diagnosing the state of a battery, which can diagnose the state of the battery in a non-destructive manner based on the battery's voltage and capacity.

[0008] These and other objects and advantages of this disclosure will become apparent from the following detailed description and from the exemplary embodiments thereof. Furthermore, it will be readily understood that the objects and advantages of this disclosure can be achieved by the means shown in the appended claims and combinations thereof.

[0009] Technical solution

[0010] An apparatus for diagnosing the state of a battery according to one aspect of the present disclosure may include: a curve acquisition unit configured to acquire a plurality of differential curves representing the correspondence between differential capacity and battery voltage, wherein differential capacity represents the rate of change of battery capacity relative to battery voltage; a peak determination unit configured to determine a target peak value located in a predetermined voltage segment in each of the plurality of differential curves; and a state diagnosis unit configured to compare the voltage of the plurality of target peak values ​​determined by the peak determination unit with the voltage of a preset reference peak value corresponding to each of the plurality of target peak values, and diagnose the state of the battery based on the voltage comparison result.

[0011] The status diagnostic unit can be configured to diagnose the battery status as abnormal when the voltage of at least one of a plurality of target peaks is less than the voltage of the corresponding reference peak.

[0012] The status diagnostic unit can be configured to set a standard peak among multiple target peaks and calculate the voltage change rate of each of the multiple target peaks based on the voltage of the set standard peak.

[0013] The condition diagnostic unit can be configured to calculate the reference rate of change for each of the multiple reference peaks based on the voltage of a reference peak corresponding to a set standard peak among multiple reference peaks corresponding to multiple target peaks.

[0014] The state diagnostic unit can be configured to compare the corresponding voltage change rate and reference change rate based on the correspondence between multiple target peaks and multiple reference peaks, and diagnose the state of the battery based on the change rate comparison result and the voltage comparison result.

[0015] The status diagnostic unit can be configured to diagnose the battery status as abnormal when the voltage and voltage change rate of at least one of a plurality of target peaks are less than the voltage and reference change rate of a reference peak, respectively.

[0016] The curve acquisition unit can be configured to acquire the differential curves of the battery at multiple time points that are different from each other.

[0017] Multiple time points can be multiple cycle time points or multiple degradation time points of the battery.

[0018] According to another aspect of this disclosure, a battery pack may include a device for diagnosing the state of the battery, according to one aspect of this disclosure.

[0019] A method for diagnosing the state of a battery according to another aspect of this disclosure may include: a curve acquisition step, which acquires a plurality of differential curves representing the correspondence between differential capacity and battery voltage, wherein differential capacity represents the rate of change of battery capacity relative to battery voltage; a peak determination step, which determines a target peak value located in a predetermined voltage segment in each of the plurality of differential curves; a comparison step, which compares the voltage of the plurality of target peak values ​​determined in the peak determination step with the voltage of a preset reference peak value corresponding to each of the plurality of target peak values; and a state diagnosis step, which diagnoses the state of the battery based on the voltage comparison result of the comparison step.

[0020] Technical effect

[0021] According to one aspect of this disclosure, an advantage is that the state of a battery can be diagnosed based on its differential curve. Specifically, the advantage is that batteries with a potential for a sudden drop in SOH (State of Health) can be diagnosed based on the voltage and / or rate of change of voltage at a target peak included in the differential curve.

[0022] The effects of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the appended claims other effects not mentioned herein. Attached Figure Description

[0023] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing description of the invention, serve to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure should not be construed as limiting the scope of the drawings.

[0024] Figure 1 This is a schematic diagram illustrating a device for diagnosing the state of a battery according to an embodiment of the present disclosure.

[0025] Figure 2 This is a diagram schematically showing the SOH of the first and second batteries according to embodiments of the present disclosure.

[0026] Figures 3 to 6 It is a graph showing the differential curves of the first and second batteries according to embodiments of the present disclosure.

[0027] Figure 7 This is a diagram schematically illustrating an exemplary construction of a battery pack according to another embodiment of the present disclosure.

[0028] Figure 8 This is a diagram schematically illustrating a method for diagnosing the state of a battery according to another embodiment of this disclosure. Detailed Implementation

[0029] It should be understood that the terms used in the specification and appended claims should not be construed as limited to their general and dictionary meanings, but rather interpreted based on their meanings and concepts corresponding to the technical solutions of this disclosure, on the basis of the principle that inventors are allowed to define terms appropriately in order to obtain the best interpretation.

[0030] Therefore, the description presented herein is merely a preferred example for illustrative purposes only and is not intended to limit the scope of this disclosure. It should be understood that other equivalents and modifications may be made thereto without departing from the scope of this disclosure.

[0031] Additionally, in describing this disclosure, detailed descriptions of relevant known elements or functions are omitted here where such descriptions would obscure the key subject matter of the disclosure.

[0032] Ordinal terms such as "first" and "second" can be used to distinguish one element from others among various elements, but are not intended to limit the element by means of the term.

[0033] Throughout this specification, when a section is referred to as “comprising” or “including” any element, unless otherwise expressly stated, this means that the section may further include other elements, without excluding other elements.

[0034] Furthermore, throughout the specification, when one part is referred to as "connected" to another part, it is not limited to the case where they are "directly connected," but also includes the case where another element is placed between them in an "indirect connection."

[0035] In the following, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0036] Figure 1 This is a schematic diagram of a device 100 for diagnosing the state of a battery according to an embodiment of the present disclosure.

[0037] Reference Figure 1 According to embodiments of the present disclosure, a device 100 for diagnosing the state of a battery may include a curve acquisition unit 110, a peak value determination unit 120, and a state diagnosis unit 130.

[0038] Here, a battery refers to a physically separable, independent unit with a negative terminal and a positive terminal. For example, a lithium-ion battery or a lithium polymer battery can be considered a battery.

[0039] The curve acquisition unit 110 can be configured to acquire multiple differential curves, which represent the relationship between differential capacity and voltage, and differential capacity represents the rate of change of battery capacity relative to battery voltage.

[0040] Here, differential capacity is the value representing the rate of change of battery capacity relative to battery voltage, and can be expressed as dQ / dV.

[0041] For example, curve acquisition unit 110 can acquire multiple differential curves representing the correspondence between the differential capacity and voltage of a battery. As another example, curve acquisition unit 110 can acquire multiple battery curves representing the correspondence between the voltage and capacity of a battery, and acquire a differential curve by calculating the differential capacity of the battery based on each of the multiple acquired battery curves.

[0042] Preferably, the curve obtaining unit 110 can be configured to obtain the differential curves of the battery at multiple time points that are different from each other.

[0043] For example, multiple time points can be multiple cycle times or multiple degradation times of the battery. That is, the curve acquisition unit 110 can obtain differential curves of multiple SOH (State of Health) values ​​for the battery. Here, SOH is an indicator of the battery's health state, and the SOH of a BOL (Beginning of Life) battery can be 1. Furthermore, as the battery degrades, its SOH can decrease.

[0044] Figure 2 This is a schematic diagram showing the SOH of the first battery B1 and the second battery B2 according to an embodiment of the present disclosure.

[0045] exist Figure 2 In this embodiment, the first battery B1 and the second battery B2 can deteriorate as the cycle progresses, thereby reducing the state of harm (SOH). In other words, the first battery B1 and the second battery B2 can deteriorate as the charge and discharge cycles proceed.

[0046] However, the state of oxygen (SOH) of the first cell B1 can gradually decrease with cycling, while the SOH of the second cell B2 may decrease rapidly with cycling. In other words, the first cell B1 can be a reference cell where the SOH does not suddenly decrease. Conversely, the second cell B2 is the cell to be diagnosed and can be an abnormal cell where the SOH suddenly decreases around 150 cycles.

[0047] For example, in Figure 2 In this embodiment, the curve obtaining unit 110 can obtain differential curves at time points when the SOH of the second battery B2 is 0.99, 0.97, 0.95, and 0.92. That is, the curve obtaining unit 110 can obtain the differential curves of the second battery B2 at multiple time points based on the SOH of the second battery B2.

[0048] Preferably, the differential curve of the first battery B1 corresponding to the reference battery can be pre-stored in the storage unit 140, and the curve acquisition unit 110 can obtain the differential curve of the second battery B2 as the target for state diagnosis.

[0049] Figures 3 to 6 This is a graph showing the differential curves of the first battery B1 and the second battery B2 according to embodiments of the present disclosure. Specifically, Figures 3 to 6 This is a graph showing the differential curves of SOH from the first time point to the fourth time point based on the first cell B1 and the second cell B2.

[0050] Figure 3 This is a graph showing the first differential curve RP1 of the first cell B1 and the first differential curve DP1 of the second cell B2 at the first time point when the SOH of the first cell B1 and the second cell B2 is 0.99.

[0051] Figure 4 This is a graph showing the second differential curve RP2 of the first cell B1 and the second differential curve DP2 of the second cell B2 at the second time point when the SOH of the first cell B1 and the second cell B2 is 0.97.

[0052] Figure 5 This is a graph showing the third differential curve RP3 of the first cell B1 and the third differential curve DP3 of the second cell B2 at the third time point when the SOH of the first cell B1 and the second cell B2 is 0.95.

[0053] Figure 6 This is a graph showing the fourth differential curve RP4 of the first cell B1 and the fourth differential curve DP4 of the second cell B2 at the fourth time point when the SOH of the first cell B1 and the second cell B2 is 0.92.

[0054] In other words, referencing Figure 2 In this implementation method, the differential curves of the first battery B1 and the second battery B2 can be obtained at the time points when the first battery B1 and the second battery B2 have the same SOH.

[0055] The peak determination unit 120 can be configured to determine a target peak value in a predetermined voltage segment located in each of a plurality of differential curves.

[0056] Specifically, the predetermined voltage range can be a local segment located in the central part of the voltage range that is set to be inoperable by the battery. For example, suppose the total voltage range set to be inoperable by the battery is above 3.3V and below 4.2V. In this case, the predetermined voltage range can be the 3.6V to 3.9V segment within the entire voltage range.

[0057] For example, the peak value determination unit 120 can determine the point with the maximum differential capacity among the points with a differential capacity of 0 in a predetermined voltage range as the peak value of the corresponding differential curve.

[0058] exist Figure 3 In this embodiment, the peak determination unit 120 can determine a first target peak value TP1 in the first differential curve DP1 of the second battery B2. The voltage corresponding to the first target peak value TP1 can be Vtp1. Meanwhile, the first differential curve RP1 of the first battery B1 can include a first reference peak value P1 corresponding to the first target peak value TP1. Furthermore, the voltage corresponding to the first reference peak value P1 can be Vp1.

[0059] exist Figure 4 In this embodiment, the peak determination unit 120 can determine a second target peak value TP2 in the second differential curve DP2 of the second battery B2. The voltage corresponding to the second target peak value TP2 can be Vtp2. Meanwhile, the second differential curve RP2 of the first battery B1 can include a second reference peak value P2 corresponding to the second target peak value TP2. Furthermore, the voltage corresponding to the second reference peak value P2 can be Vp2.

[0060] exist Figure 5 In this embodiment, the peak determination unit 120 can determine a third target peak value TP3 in the third differential curve DP3 of the second battery B2. The voltage corresponding to the third target peak value TP3 can be Vtp3. Meanwhile, the third differential curve RP3 of the first battery B1 can include a third reference peak value P3 corresponding to the third target peak value TP3. In addition, the voltage corresponding to the third reference peak value P3 can be Vp3.

[0061] exist Figure 6 In this embodiment, the peak determination unit 120 can determine a fourth target peak value TP4 in the fourth differential curve DP4 of the second battery B2. The voltage corresponding to the fourth target peak value TP4 can be Vtp4. Meanwhile, the fourth differential curve RP4 of the first battery B1 can include a fourth reference peak value P4 corresponding to the fourth target peak value TP4. In addition, the voltage corresponding to the fourth reference peak value P4 can be Vp4.

[0062] The status diagnosis unit 130 can be configured to compare the voltages of a plurality of target peaks determined by the peak determination unit 120 with the voltages of a preset reference peak corresponding to each of the plurality of target peaks.

[0063] Specifically, the status diagnostic unit 130 can directly compare the voltage amplitudes of multiple target peaks with the voltage amplitudes of the corresponding reference peaks.

[0064] For example, the state diagnostic unit 130 can compare the voltage amplitudes of a first target peak TP1 and a first reference peak P1, and can also compare the voltage amplitudes of a second target peak TP2 and a second reference peak P2. Furthermore, the state diagnostic unit 130 can compare the voltage amplitudes of a third target peak TP3 and a third reference peak P3, and can also compare the voltage amplitudes of a fourth target peak TP4 and a fourth reference peak P4.

[0065] The status diagnostic unit 130 can be configured to diagnose the battery status based on voltage comparison results.

[0066] Specifically, the state diagnosis unit 130 can be configured to diagnose the battery state as abnormal when the voltage of at least one of the plurality of target peaks is less than the voltage of the corresponding reference peak.

[0067] As mentioned above, an abnormal state refers to a condition where the battery's State of Harm (SOH) suddenly drops as the battery deteriorates. For example, when a battery is diagnosed as being in an abnormal state, it means that the battery's SOH may suddenly drop.

[0068] For example, in Figure 3 In this implementation, the voltage Vtp1 of the first target peak value TP1 can be less than the voltage Vp1 of the first reference peak value P1. Similarly, in Figure 4 In this implementation, the voltage Vtp2 of the second target peak TP2 can be less than the voltage Vp2 of the second reference peak P2. Additionally, in... Figure 5 In this implementation, the voltage Vtp3 of the third target peak TP3 can be less than the voltage Vp3 of the third reference peak P3. Furthermore, in... Figure 6 In this implementation, the voltage Vtp4 of the fourth target peak TP4 can be less than the voltage Vp4 of the fourth reference peak P4.

[0069] Therefore, the state diagnosis unit 130 can diagnose the state of the second battery B2 as an abnormal state. That is, since the voltage corresponding to the target peak value of the second battery B2 is less than the voltage corresponding to the reference peak value of the first battery B1, the state diagnosis unit 130 can diagnose the state of the second battery B2 as an abnormal state in which the SOH may suddenly drop.

[0070] In other words, the device 100 for diagnosing the state of a battery according to embodiments of this disclosure has the advantage of quickly diagnosing the state of the battery by comparing the voltage corresponding to a target peak voltage of the battery with the voltage corresponding to a reference peak voltage of a reference battery. In particular, the device 100 for diagnosing the state of a battery has the advantage of quickly diagnosing batteries at risk of sudden voltage drops based on the comparison results of the reference peak and the target peak voltage.

[0071] Furthermore, the device 100 for diagnosing the state of the battery may optionally include an application-specific integrated circuit (ASIC) known in the art, another chipset, logic circuits, registers, communication modems, and data processing devices, etc., that execute the various control logics disclosed below. Additionally, when the control logic is implemented in software, the device 100 for diagnosing the state of the battery may be implemented as a set of program modules.

[0072] Additionally, the device 100 for diagnosing the state of the battery may also include a storage unit 140. The storage unit 140 may store programs, data, etc., required for diagnosing the state of the battery according to this disclosure. That is, the storage unit 140 may store data required for the operation and function of each component of the device 100 for diagnosing the state of the battery, data generated during the execution of operations or functions, etc. The storage unit 140 is not particularly limited in type, as long as it is a known information storage device capable of recording, erasing, updating, and retrieving data. As examples, the information storage device may include RAM, flash memory, ROM, EEPROM, registers, etc. Furthermore, the storage unit 140 may store program code that defines executable processes for each component of the device 100 for diagnosing the state of the battery.

[0073] For example, storage unit 140 can store multiple differential curve files of the battery. In this case, curve acquisition unit 110 can access storage unit 140 to obtain multiple differential curves of the battery.

[0074] As another example, storage unit 140 can store multiple battery curves of the battery. In this case, curve acquisition unit 110 can access storage unit 140 to obtain multiple battery curves of the battery, and obtain multiple differential curves based on the multiple obtained battery curves.

[0075] In another embodiment, the status diagnostic unit 130 can be configured to set a standard peak among a plurality of target peaks.

[0076] For example, the condition diagnostic unit 130 can set the target peak with the lowest degree of battery degradation among multiple target peaks as the standard peak. Specifically, the condition diagnostic unit 130 can set the target peak with the lowest voltage as the standard peak.

[0077] For example, refer to Figures 3 to 6 The status diagnostic unit 130 can set the first target peak TP1, which has the lowest corresponding voltage among the first target peak TP1, the second target peak TP2, the third target peak TP3 and the fourth target peak TP4, as the standard peak.

[0078] The status diagnostic unit 130 can be configured to calculate the rate of change of voltage for each of a plurality of targets based on a set standard peak voltage.

[0079] For example, the state diagnostic unit 130 can calculate the voltage change rate of each of the second target peak TP2, the third target peak TP3, and the fourth target peak TP4 based on the voltage of the standard peak (i.e., the first target peak TP1). Here, since the voltage change rate of the first target peak TP1 is 0, it is assumed that the voltage change rate of the first target peak TP1 can be omitted. Specifically, the state diagnostic unit 130 can calculate the voltage change rate according to the formula "(voltage of the nth target peak - voltage of the standard peak) ÷ voltage of the standard peak" or "voltage of the nth target peak - voltage of the standard peak". Here, n is a positive number.

[0080] Additionally, the status diagnostic unit 130 can be configured to calculate the reference rate of change for each of the plurality of reference peaks based on the voltage of a reference peak corresponding to a set standard peak among a plurality of reference peaks corresponding to a plurality of target peaks.

[0081] For example, the condition diagnostic unit 130 can calculate the reference rate of change for each of the second reference peak P2, the third reference peak P3, and the fourth reference peak P4 based on the voltage of the first reference peak P1 corresponding to the standard peak (i.e., the first target peak P1). Here, since the reference rate of change for the first reference peak P1 is 0, it is assumed that the reference rate of change for the first reference peak P1 can be omitted. Here, the condition diagnostic unit 130 can calculate the reference rate of change for each reference peak by applying the method for calculating the voltage rate of change of the target peak to multiple reference peaks.

[0082] Meanwhile, since the reference peak value is preset, the reference change rate of multiple reference peak values ​​can also be preset.

[0083] The status diagnostic unit 130 can be configured to compare the corresponding voltage change rate and reference change rate based on the correspondence between multiple target peaks and multiple reference peaks.

[0084] For example, the state diagnostic unit 130 can compare the second voltage change rate of the second target peak TP2 with the second reference change rate of the second reference peak P2. Additionally, the state diagnostic unit 130 can compare the third voltage change rate of the third target peak TP3 with the third reference change rate of the third reference peak P3. Furthermore, the state diagnostic unit 130 can compare the fourth voltage change rate of the fourth target peak TP4 with the fourth reference change rate of the fourth reference peak P4.

[0085] The state diagnostic unit 130 can be configured to diagnose the state of the battery based on the rate of change comparison results and the voltage comparison results.

[0086] Specifically, the state diagnosis unit 130 can be configured to diagnose the battery state as abnormal when the voltage and voltage change rate of at least one of a plurality of target peaks are less than the voltage and reference change rate of the corresponding reference peak, respectively.

[0087] In other words, the state diagnostic unit 130 can diagnose the state of the battery by further considering the voltage change rate and voltage of multiple target peaks and multiple reference peaks.

[0088] Specifically, when the voltage change rate of the target peak of the second battery B2 is less than the reference change rate of the standard peak of the corresponding first battery B1, and the voltage of the target peak of the second battery B2 is less than the voltage of the standard peak of the corresponding first battery B1, the state diagnosis unit 130 can diagnose the state of the second battery B2 as an abnormal state.

[0089] For example, refer to Figure 3 and Figure 4 In this implementation, the voltage Vtp2 of the second target peak TP2 can be less than the voltage Vp2 of the second reference peak P2. However, the rate of change of the voltage of the second target peak TP2 can be greater than the reference rate of change of the second reference peak P2. Therefore, the state diagnostic unit 130 can be based on... Figure 3 and Figure 4 In this implementation method, the state of the second battery B2 is not diagnosed as an abnormal state.

[0090] As another example, see Figure 3 and Figure 5 In this implementation, the voltage Vtp3 of the third target peak TP3 can be less than the voltage Vp3 of the third reference peak P3. Furthermore, the voltage change rate of the third target peak TP3 can be less than the reference change rate of the third reference peak P3. Similarly, referring to... Figure 3 and Figure 6 In this implementation, the voltage Vtp4 of the fourth target peak TP4 can be less than the voltage Vp4 of the fourth reference peak P4. Furthermore, the voltage change rate of the fourth target peak TP4 can be less than the reference change rate of the fourth reference peak P4. Therefore, the state diagnostic unit 130 can be based on... Figure 3 , Figure 5 and Figure 6 In this implementation method, the state of the second battery B2 is diagnosed as an abnormal state.

[0091] The device 100 for diagnosing battery status according to embodiments of this disclosure has the advantage of more accurately diagnosing battery status by further considering the battery's voltage change rate and voltage. Specifically, the device 100 for diagnosing battery status has the advantage of specifically diagnosing the status of abnormal batteries with the possibility of a sudden drop in SOH based on the battery's voltage and voltage change rate. Therefore, even if the battery's SOH is not continuously tracked during the battery's lifespan, batteries with a risk of a sudden drop in SOH can be conveniently selected.

[0092] More specifically, the state diagnostic unit 130 can determine an increase / decrease pattern of the voltage change rate corresponding to multiple target peaks. Furthermore, when the determined increase / decrease pattern is an increase pattern and the voltage and voltage change rate of at least one of the multiple target peaks are less than the voltage and reference change rate of the corresponding reference peak, the state diagnostic unit 130 can be configured to diagnose the battery state as abnormal.

[0093] For example, refer to Figures 3 to 6 In this implementation, the voltages corresponding to the first target peak TP1 to the fourth target peak TP4 can increase as the second battery B2 deteriorates. That is, as time passes to the second time point (SOH 0.97), the third time point (SOH 0.95), and the fourth time point (SOH 0.92), the voltage change rate of the second battery B2 can gradually increase. Therefore, the state diagnostic unit 130 can determine the increase / decrease pattern of the voltage change rate of the second battery B2 as an increasing pattern.

[0094] Then, the state diagnosis unit 130 can compare the voltage and voltage change rate of at least one of the multiple target peaks of the second battery B2 with the voltage and reference change rate of a reference peak, and diagnose the state of the second battery B2 based on the comparison results.

[0095] As in the example above, the voltage Vtp3 of the third target peak TP3 can be less than the voltage Vp3 of the third reference peak P3, and the voltage Vtp4 of the fourth target peak TP4 can be less than the voltage Vp4 of the fourth reference peak P4. Furthermore, the rate of change of the voltage of the third target peak TP3 can be less than the reference rate of change of the third reference peak P3, and the rate of change of the voltage of the fourth target peak TP4 can be less than the reference rate of change of the fourth reference peak P4.

[0096] Therefore, the status diagnosis unit 130 can diagnose the status of the second battery B2 as an abnormal state.

[0097] In other words, the device 100 for diagnosing battery condition according to the embodiments of this disclosure has the following advantages: because the target peak and reference peak are specifically compared after first considering the increase / decrease pattern of the battery's voltage change rate, the battery condition can be diagnosed more quickly. Specifically, when the battery's voltage change rate is determined to be in an increasing pattern, the device 100 for diagnosing battery condition can determine that battery degradation is gradually accelerating, and only in this case can the battery condition be diagnosed more quickly and accurately by diagnosing whether the battery is a battery with the possibility of a sudden drop.

[0098] The device 100 for diagnosing the state of a battery according to this disclosure can be applied to a BMS (Battery Management System). That is, a BMS according to this disclosure may include the aforementioned device 100 for diagnosing the state of a battery. In this configuration, at least some components of the device 100 for diagnosing the state of a battery can be implemented by supplementing or adding functionality to configurations included in conventional BMSs. For example, the curve acquisition unit 110, peak determination unit 120, state diagnosis unit 130, and storage unit 140 of the device 100 for diagnosing the state of a battery can be implemented as components of a BMS.

[0099] Furthermore, the device 100 for diagnosing the state of a battery according to this disclosure can be provided to the battery pack 1. For example, the battery pack 1 according to this disclosure may include the device 100 for diagnosing the state of a battery as described above, the measuring unit 200, and at least one battery B. In addition, the battery pack 1 may also include electrical equipment (relays, fuses, etc.), a housing, etc.

[0100] Figure 7 This is a diagram schematically illustrating an example construction of a battery pack 1 according to another embodiment of the present disclosure.

[0101] The measurement unit 200 can be connected to the first sensing line SL1, the second sensing line SL2 and the third sensing line SL3.

[0102] Specifically, the first sensing line SL1 can be connected to the positive terminal of battery B and the measuring unit 200. Similarly, the second sensing line SL2 can be connected to the negative terminal of battery B and the measuring unit 200. The measuring unit 200 can measure the voltage of battery B by calculating the difference between the positive terminal voltage of battery B measured via the first sensing line SL1 and the negative terminal voltage of battery B measured via the second sensing line SL2.

[0103] Additionally, the measurement unit 200 can measure the charging current and / or discharging current of the battery B via a current measurement unit A connected to the third sensing line SL3. For example, the current measurement unit A can be a shunt resistor or an ammeter.

[0104] The voltage and current of battery B measured by the measuring unit 200 can be transmitted to the device 100 used to diagnose the state of the battery.

[0105] For example, curve acquisition unit 110 can receive the voltage and current of battery B from measurement unit 200. Based on the received voltage and current of battery B, curve acquisition unit 110 can generate a differential curve representing the correspondence between the voltage and differential capacity of battery B.

[0106] As another example, storage unit 140 can receive and store the voltage and current of battery B from measurement unit 200. Curve acquisition unit 110 can access storage unit 140 to obtain battery curves of voltage and current, and generate differential curves based on the obtained battery curves.

[0107] As another example, the curve acquisition unit 110 can directly receive from the measurement unit 200 a differential curve representing the relationship between the differential capacity and voltage of battery B.

[0108] Figure 8 This is a diagram schematically illustrating a method for diagnosing the state of a battery according to another embodiment of this disclosure.

[0109] Preferably, the steps of the method for diagnosing the state of the battery can be performed by the device 100 for diagnosing the state of the battery. In the following, content overlapping with the previously described content will be omitted or briefly described.

[0110] Reference Figure 8 A method for diagnosing the state of a battery according to another embodiment of the present disclosure may include a curve acquisition step (S100), a peak value determination step (S200), a comparison step (S300), and a state diagnosis step (S400).

[0111] The curve acquisition step (S100) is a step of acquiring multiple differential curves representing the correspondence between differential capacity and voltage, where differential capacity represents the rate of change of battery capacity relative to battery voltage, and the curve acquisition step can be performed by the curve acquisition unit 110.

[0112] For example, in Figures 3 to 6 In this embodiment, the curve acquisition unit 110 can acquire multiple differential curves of the second battery B2.

[0113] The peak determination step (S200) is a step of determining the target peak value of a predetermined voltage segment located in each of the plurality of differential curves, and can be performed by the peak determination unit 120.

[0114] For example, in Figures 3 to 6In this implementation, the peak determination unit 120 can determine a target peak value in each of the plurality of differential curves of the second battery B2. Specifically, the peak determination unit 120 can determine a first target peak value TP1 in the first differential curve DP1 and a second target peak value TP2 in the second differential curve DP2. In addition, the peak determination unit 120 can determine a third target peak value TP3 in the third differential curve DP3 and a fourth target peak value TP4 in the fourth differential curve DP4.

[0115] The comparison step (S300) is a step of comparing the voltage of a plurality of target peaks determined in the peak determination step (S200) with the voltage of a preset reference peak corresponding to each of the plurality of target peaks, and can be performed by the state diagnosis unit 130.

[0116] For example, the condition diagnostic unit 130 can compare the voltage and / or voltage change rate of corresponding target peak and reference peak.

[0117] The state diagnosis step (S400) is a step of diagnosing the state of the battery based on the voltage comparison result of the comparison step (S300), and can be executed by the state diagnosis unit 130.

[0118] For example, the state diagnosis unit 130 can diagnose the state of a battery with a potential for a sudden drop in SOH as an abnormal state based on the comparison results.

[0119] The embodiments of this disclosure described above are not necessarily to be implemented by devices and methods, but can also be implemented by a program for implementing functions corresponding to the configuration of this disclosure or a recording medium containing such a program. Those skilled in the art can readily perform such implementations based on the above description of the embodiments.

[0120] This disclosure has been described in detail. However, it should be understood that while the detailed description and specific examples indicate preferred embodiments of this disclosure, they are given by way of illustration only, as various variations and modifications within the scope of this disclosure will become apparent to those skilled in the art based on this detailed description.

[0121] Additionally, those skilled in the art can make many substitutions, modifications and variations to the above-described disclosure without departing from the technical solution of this disclosure, and this disclosure is not limited to the above embodiments and drawings, and each embodiment can be selectively combined in part or in whole to allow for various modifications.

[0122] (List of reference numerals in the attached diagram)

[0123] 1: Battery pack

[0124] 100: Devices used to diagnose the condition of batteries

[0125] 110: Curve Acquisition Unit

[0126] 120: Peak value determination unit

[0127] 130: Status Diagnostic Unit

[0128] 140: Storage unit

[0129] 200: Measurement Unit

[0130] B: Battery

Claims

1. An apparatus for diagnosing the state of a battery, the apparatus comprising: A curve acquisition unit is configured to acquire, at each of a plurality of time points that are different from each other, a differential curve representing the relationship between differential capacity and the voltage of the battery, wherein the differential capacity represents the rate of change of the battery capacity relative to the voltage. A peak determination unit is configured to determine a target peak value located in a predetermined voltage segment in each of the acquired plurality of differential curves; as well as A state diagnostic unit is configured to compare the voltages of a plurality of target peaks determined by the peak determination unit with the voltage of a preset reference peak corresponding to each of the plurality of target peaks, and to diagnose the state of the battery based on the voltage comparison results. The status diagnostic unit is configured to compare the voltage of the target peak corresponding to the same time point with the voltage of the reference peak.

2. The device for diagnosing the state of a battery according to claim 1, in, The state diagnosis unit is configured to diagnose the battery state as abnormal when the voltage of at least one of the plurality of target peak values ​​is less than the voltage of the corresponding reference peak value.

3. The device for diagnosing the state of a battery according to claim 1, in, The status diagnostic unit is configured to set a standard peak value among the plurality of target peak values, and to calculate the voltage change rate for each of the plurality of target peak values ​​based on the voltage of the set standard peak value.

4. The device for diagnosing the state of a battery according to claim 3, in, The condition diagnostic unit is configured to set the target peak with the lowest degree of battery degradation among the plurality of target peaks as the standard peak.

5. The device for diagnosing the state of a battery according to claim 4, in, The state diagnostic unit is configured to calculate a reference rate of change for each of the plurality of reference peaks based on the voltage of a reference peak corresponding to a set standard peak among a plurality of reference peaks corresponding to the plurality of target peaks.

6. The apparatus for diagnosing the state of a battery according to claim 5, in, The condition diagnostic unit is configured to calculate the voltage change rate according to the following formula: (Voltage of the nth target peak - Voltage of the standard peak) ÷ Voltage of the standard peak, or The voltage of the nth target peak - the voltage of the standard peak, and Where n is a positive number.

7. The apparatus for diagnosing the state of a battery according to claim 6, in, The state diagnostic unit is configured to compare the corresponding voltage change rate and the reference change rate based on the correspondence between the plurality of target peak values ​​and the plurality of reference peak values, and to diagnose the state of the battery based on the comparison result of the voltage change rate and the reference change rate and the voltage comparison result.

8. The apparatus for diagnosing the state of a battery according to claim 7, in, The state diagnosis unit is configured to diagnose the battery state as abnormal when the voltage and voltage change rate of at least one of the plurality of target peaks are respectively less than the voltage and reference change rate of the reference peak.

9. The apparatus for diagnosing the state of a battery according to claim 1, in, The curve acquisition unit is configured to acquire differential curves of the battery at multiple time points that are different from each other.

10. The apparatus for diagnosing the state of a battery according to claim 9, in, The multiple time points are multiple cycle time points or multiple degradation time points of the battery.

11. A battery pack comprising a device for diagnosing the state of a battery according to any one of claims 1 to 10.

12. A method for diagnosing the state of a battery, the method comprising the steps of: The curve acquisition step obtains a differential curve representing the relationship between differential capacity and the voltage of the battery at each of a plurality of time points that are different from each other, wherein the differential capacity represents the rate of change of the battery capacity relative to the voltage. A peak determination step, which determines the target peak value located in a predetermined voltage segment in each of the multiple obtained differential curves; The comparison step compares the voltage of a plurality of target peaks determined in the peak determination step with the voltage of a preset reference peak corresponding to each of the plurality of target peaks. as well as A state diagnosis step, which diagnoses the state of the battery based on the voltage comparison result of the comparison step, The state diagnosis step includes comparing the voltage of the target peak corresponding to the same time point with the voltage of the reference peak.

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