Apparatus and method for diagnosing battery

Abstract

A battery diagnostic device according to one embodiment of the present invention includes: a profile acquisition unit configured to acquire a battery profile representing a correspondence relationship between the voltage and capacity of a battery; and a control unit configured to divide the capacity range of the battery profile into a plurality of ranges, derive a target value for one of a target indicator related to a differential capacity peak among a plurality of diagnostic indicators set in advance in each range, compare the correspondence relationship between the derived plurality of target values ​​with a reference profile set in advance to represent a correspondence relationship between the plurality of target indicators, and diagnose the state of the battery according to the comparison result.

Description

Technology Field

[0001] The present invention relates to a battery diagnostic device and method, and more specifically, to a battery diagnostic device and method for diagnosing the condition of a battery. Background Technology

[0002] Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has increased rapidly, and the development of electric vehicles, energy storage batteries, robots, and satellites has accelerated, research on high-performance batteries capable of repeated charging and discharging is actively underway.

[0003] Currently commercialized batteries include nickel-cadmium, nickel-hydrogen, nickel-zinc, and lithium batteries. Among these, lithium batteries are gaining attention for their advantages, such as the ability to freely charge and discharge with almost no memory effect compared to nickel-based batteries, a very low self-discharge rate, and high energy density.

[0004] While extensive research is being conducted on these batteries in terms of increasing capacity and density, improving lifespan and safety is also crucial. To enhance battery safety, technology capable of accurately diagnosing the battery's current state is required. The problem to be solved

[0005] The present invention is designed to solve the above-mentioned problems and aims to provide a battery diagnostic device and method that diagnose the condition of a battery and control the battery according to the diagnosis result.

[0006] Other objects and advantages of the present invention may be understood from the following description and will become more clearly apparent from the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. means of solving the problem

[0007] A battery diagnostic device according to one aspect of the present invention may include: a profile acquisition unit configured to acquire a battery profile representing a correspondence relationship between the voltage and capacity of a battery; and a control unit configured to divide the capacity range of the battery profile into a plurality of ranges, derive a target value for one of a target indicator related to a differential capacity peak among a plurality of diagnostic indicators set in advance in each range, compare the correspondence relationship between the derived plurality of target values ​​with a reference profile set in advance to represent a correspondence relationship between the plurality of target indicators, and diagnose the state of the battery according to the comparison result.

[0008] The control unit may be configured to determine, for each of the above sections, the number of multiple differential capacity peaks included in a differential profile corresponding to the battery profile and representing a correspondence relationship between voltage and differential capacity, the area of ​​the differential profile, the voltage of the main peak among the multiple differential capacity peaks, or the differential capacity of the main peak as the target indicator.

[0009] The control unit may be configured to diagnose the state of the battery as positive / negative degeneration state when a target point representing a correspondence relationship between the plurality of target values ​​is included in the reference profile.

[0010] The control unit may be configured to diagnose the state of the battery as a negative degradation state when the target point is included in a first region based on the reference profile.

[0011] The control unit may be configured to diagnose the state of the battery as positive degradation if the target point is included in the second region based on the reference profile.

[0012] The above control unit may be configured to diagnose the state of the battery as EOL when the target point is included in the third region.

[0013] The third region above may be configured to be pre-set as a region exceeding a preset threshold for each of the plurality of target indicators.

[0014] The control unit may be configured to reduce at least one of the upper limit C-rate and constant voltage charging time set for the battery when the state of the battery is diagnosed as the positive degeneration state or the positive / negative degeneration state.

[0015] The control unit may be configured to reduce the charging upper limit voltage set for the battery when the state of the battery is diagnosed as the negative degeneration state or the positive / negative degeneration state.

[0016] The above control unit may be configured to divide the capacity range into a first range and a second range based on a preset division ratio or target capacity.

[0017] The above profile acquisition unit may be configured to further acquire a differential profile corresponding to the battery profile.

[0018] The control unit above may be configured to determine the main peak in the differential profile and to distinguish the capacity range based on the capacity of the determined main peak.

[0019] The above differential profile can be configured to show a corresponding relationship between the capacity of the battery and the differential voltage.

[0020] The control unit may be configured to determine a plurality of local minima in the differential profile and to determine the local minima among the determined plurality of local minima that has the smallest corresponding differential voltage as the main peak.

[0021] The above differential profile can be configured to show a corresponding relationship between the voltage and differential capacity of the battery.

[0022] The control unit may be configured to determine a plurality of maximum points in the differential profile and to determine the maximum point among the determined plurality of maximum points that has the largest corresponding differential voltage as the main peak.

[0023] 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.

[0024] An automobile according to another aspect of the present invention may include a battery diagnostic device according to one aspect of the present invention.

[0025] A battery diagnostic method according to another aspect of the present invention may include: a profile acquisition step of acquiring a battery profile representing a correspondence relationship between the voltage and capacity of a battery; a segment division step of dividing the capacity segment of the battery profile into a plurality of segments; a target value derivation step of deriving a target value for one of a target indicator related to a differential capacity peak among a plurality of diagnostic indicators set in advance in each segment; a comparison step of comparing the correspondence relationship between the derived plurality of target values ​​with a reference profile set in advance to represent a correspondence relationship between the plurality of target indicators; and a diagnostic step of diagnosing the state of the battery according to the comparison result. Effects of the invention

[0026] According to one aspect of the present invention, there is an advantage that the condition of the battery can be diagnosed in various aspects depending on a combination of various target indicators.

[0027] In particular, since the target value for each section represents the state of the battery corresponding to that section, the state of the battery can be diagnosed more specifically by separating it based on the correspondence relationship of multiple target values.

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

[0029] The following drawings attached to this specification serve to further enhance understanding of the technical concept of the invention in conjunction with the detailed description of the invention set forth below; therefore, the invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is a schematic diagram illustrating a battery diagnostic device according to one embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a battery profile according to one embodiment of the present invention. FIG. 3 is a schematic diagram illustrating a plurality of target indicators according to one embodiment of the present invention. FIG. 4 is a schematic diagram illustrating a reference profile according to one embodiment of the present invention. FIG. 5 is a schematic diagram illustrating a differential profile according to one embodiment of the present invention. FIG. 6 is a schematic diagram illustrating a battery pack according to another embodiment of the present invention. FIG. 7 is a schematic drawing illustrating an automobile according to another embodiment of the present invention. FIG. 8 is a schematic diagram illustrating a battery diagnostic method according to another embodiment of the present invention. Specific details for implementing the invention

[0030] Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0031] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0032] In addition, in describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the invention, such detailed description is omitted.

[0033] Terms including ordinal numbers, such as first, second, etc., are used for the purpose of distinguishing one of the various components from the rest, and are not used to limit the components by such terms.

[0034] Throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0035] Additionally, throughout the specification, when it is said that a part is "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other components in between.

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

[0038] FIG. 1 is a schematic diagram illustrating a battery diagnostic device (100) according to one embodiment of the present invention.

[0039] Referring to FIG. 1, the battery diagnostic device (100) may include a profile acquisition unit (110), a control unit (120), and a storage unit (130).

[0040] Here, a battery refers to a single, independent cell that is physically separable and equipped with a negative terminal and a positive terminal. For example, a lithium-ion battery or a lithium-polymer battery may be considered a battery. Additionally, the battery may be of the cylindrical, prismatic, or pouch type. Furthermore, a battery may refer to a battery bank, battery module, or battery pack in which multiple cells are connected in series and / or parallel. For the sake of convenience of explanation, the term "battery" below is described as referring to a single, independent cell.

[0041] The profile acquisition unit (110) may be configured to acquire a battery profile (BP) that indicates the corresponding relationship between the voltage and capacity of the battery.

[0042] For example, a battery profile (BP) is a profile that represents the correspondence between voltage (V) and capacity (Q) when the battery is charged from a preset starting charge capacity or 0% to a preset ending charge capacity or 100%. As another example, a battery profile (BP) may also represent the correspondence between voltage (V) and capacity (Q) when the battery is discharged from a preset starting discharge capacity or 100% to a preset ending discharge capacity or 0%.

[0043] For example, there is no specific limit on the C-rate during charging or discharging for generating a battery profile (BP). However, preferably, to obtain a more accurate battery profile (BP) and differential profile, the battery must be charged or discharged at a low rate. For example, a battery profile (BP) can be generated during the process of charging or discharging the battery at 0.05C.

[0044] For example, the profile acquisition unit (110) can directly receive the battery profile (BP) of the battery from the outside. That is, the profile acquisition unit (110) can acquire the battery profile (BP) by receiving the battery profile (BP) through a wired and / or wireless connection with the outside.

[0045] As another example, the profile acquisition unit (110) can receive battery information regarding the voltage and capacity of the battery. Then, the profile acquisition unit (110) can generate a battery profile (BP) based on the received battery information. That is, the profile acquisition unit (110) can acquire a battery profile (BP) by directly generating a battery profile (BP) based on the battery information.

[0046] FIG. 2 is a schematic diagram illustrating a battery profile (BP) according to an embodiment of the present invention. In the embodiment of FIG. 2, the battery profile (BP) can be represented as an XY graph in which the X-axis is set as capacity (Q) and the Y-axis is set as voltage (V).

[0047] The profile acquisition unit (110) can be connected to the control unit (120) so as to be able to communicate with it. For example, the profile acquisition unit (110) can be connected to the control unit (120) via wired and / or wireless connections. The profile acquisition unit can transmit the acquired battery profile (BP) to the control unit (120).

[0048] The control unit (120) may be configured to divide the capacity range of the battery profile (BP) into multiple ranges.

[0049] Specifically, the control unit (120) can divide the entire capacity range of the battery profile (BP) into two or more ranges. For example, in the embodiment of FIG. 2, the capacity range of the battery profile (BP) is Qi to Qf. The control unit (120) can divide the capacity range of Qi to Qf into a first range (R1) and a second range (R2) based on Qk.

[0050] The control unit (120) may be configured to derive a target value for one of the target indicators related to the differential capacity peak among a plurality of diagnostic indicators pre-set in each section.

[0051] Specifically, multiple diagnostic indicators may be pre-set for each of the multiple sections. Here, the diagnostic indicator serves as an indicator representing the battery status in the corresponding section and can be used to diagnose the battery status in that section. For example, since there are specific indicators that can only be derived from each of the multiple sections, the diagnostic indicators set for each of the multiple sections may differ in some or all.

[0052] FIG. 3 is a schematic diagram illustrating a plurality of target indicators according to one embodiment of the present invention.

[0053] (1) The number of differential voltage peaks is the number of peaks included in the corresponding section of the first differential profile. For example, the number of maximum and / or minimum points included in the corresponding section of the first differential profile can be determined as the number of differential voltage peaks.

[0054] Here, the differential voltage peak refers to a peak included in the first differential profile obtained by differentiating the battery profile (BP) with respect to capacity. For example, when the battery profile (BP) is differentiated with respect to capacity, a first differential profile representing the correspondence between capacity (Q) and differential voltage (dV / dQ) can be derived. Furthermore, the first differential profile may include multiple differential voltage peaks. Here, the differential voltage peak refers to a maximum and / or minimum included in the first differential profile.

[0055] (2) The capacity of the differential voltage peak is the capacity of the target peak included in the corresponding section of the first differential profile. For example, among one or more maximum points included in the corresponding section of the first differential profile, the peak with the largest corresponding differential voltage can be determined as the target peak. The target peak may be changed depending on the condition of the battery to be diagnosed.

[0056] (3) The derivative voltage of the derivative voltage peak is the derivative voltage of the target peak included in the corresponding section of the first derivative profile.

[0057] (4) The differential voltage area is the area of ​​the corresponding section of the first differential profile. The value of the corresponding section of the first differential profile integrated with respect to capacitance can be determined as the differential voltage area.

[0058] (5) The number of derivative capacitance peaks is the number of peaks included in the corresponding section of the second derivative profile. For example, the number of maximum and / or minimum points included in the corresponding section of the second derivative profile can be determined as the number of derivative voltage peaks.

[0059] Here, the differential capacity peak refers to a peak included in the second differential profile obtained by differentiating the battery profile (BP) with respect to voltage. For example, when the battery profile (BP) is differentiated with respect to voltage, a second differential profile representing the correspondence between voltage (V) and differential capacity (dQ / dV) can be derived. Furthermore, the second differential profile may include multiple differential capacity peaks. Here, the differential capacity peak refers to a maximum and / or minimum included in the second differential profile.

[0060] (6) The capacity of the differential capacity peak is the capacity of the target peak included in the corresponding section of the second differential profile. For example, among one or more maximum points included in the corresponding section of the second differential profile, the peak with the largest corresponding differential voltage can be determined as the target peak. The target peak may be changed depending on the condition of the battery to be diagnosed.

[0061] (7) The derivative of the

[0062] (8) The differential capacitance area is the area of ​​the corresponding section of the second differential profile. The value of the corresponding section of the second differential profile integrated with respect to voltage can be determined as the differential capacitance area.

[0063] (9) The discharge end voltage refers to the open circuit voltage (OCV) after the discharge of the battery has ended. Since the discharge end voltage can be obtained when the discharge of the battery has ended, it is a diagnostic indicator that can be obtained only in the low-capacity range. Specifically, the discharge end voltage can be obtained in the low-capacity range corresponding to the voltage set to end the discharge of the battery.

[0064] (10) The charging end voltage refers to the OCV after the battery has finished charging. Since the charging end voltage can be derived when the battery finishes charging, it is a diagnostic indicator that can be derived only in the high-capacity range. Specifically, the charging end voltage can be derived in the high-capacity range corresponding to the voltage set to finish charging the battery.

[0065] (11) The resistance of a section refers to the ratio of the change in voltage to the charge / discharge current of that section.

[0066] (12) Charging efficiency refers to the difference between the charging capacity and the discharging capacity. For example, the charging efficiency of the low-capacity section in the nth cycle can be calculated according to the formula “charging capacity of the nth cycle - discharging capacity of the nth cycle”. And, the charging efficiency of the high-capacity section in the nth cycle can be calculated according to the formula “discharging capacity of the nth cycle - charging capacity of the n+1th cycle”. That is, the charging efficiency is not limited to that section only, but can be calculated according to the total charging and discharging capacity of the cycle.

[0067] (13) The section capacity refers to the capacity of the corresponding section.

[0068] (14) The CC charging capacity ratio refers to the ratio of the CC (constant current) charging capacity to the CV (constant voltage) charging capacity. Since CV charging is performed at the end of the charging process, the CC charging capacity ratio is a diagnostic indicator that can be derived only in the high-capacity range. Specifically, the CC charging capacity ratio can be derived in the high-capacity range corresponding to the voltage set to end the battery charging process.

[0069] Preferably, the control unit (120) may be configured to determine, for each section, the number of differential capacity peaks included in a differential profile that corresponds to the battery profile and represents the corresponding relationship between voltage and differential capacity, the area of ​​the differential profile, the voltage of the main peak among the differential capacity peaks, or the differential capacity of the main peak as a target indicator.

[0070] For example, in the embodiment of FIG. 3, the control unit (120) can determine, for each section, any one of the number of differential capacitance peaks, the voltage of the differential capacitance peaks, the differential capacitance of the differential capacitance peaks, and the differential capacitance area as a target indicator.

[0071] The control unit (120) may be configured to compare the correspondence relationship between the derived multiple target values ​​with a preset reference profile to represent the correspondence relationship between the multiple target indicators.

[0072] Specifically, it is assumed that the capacity range of the battery profile (BP) is divided into a first range (R1) and a second range (R2), that a first target value for a target indicator is derived in the first range (R1), and that a second target value for a target indicator is derived in the second range (R2). The control unit (120) can compare a target point representing a correspondence relationship of a plurality of target values ​​with a reference profile.

[0073] FIG. 4 is a schematic diagram illustrating a reference profile according to an embodiment of the present invention. In the embodiment of FIG. 4, the reference profile may be represented as an XY graph in which the X-axis is set to a second target value and the Y-axis is set to a first target value.

[0074] Specifically, the control unit (120) can determine whether the target point is included in the reference profile. If the target point is not included in the reference profile, the control unit (120) can determine which of the first area (T1), the second area (T2), and the third area (T3) the target point is included in.

[0075] Here, the first region (T1) is a region where the first target value is larger based on the reference profile. For example, in the embodiment of FIG. 4, the first region (T1) is a region where the first target value of the target point exceeds the first target value of the reference profile based on the same second target value.

[0076] Here, the second region (T2) is a region where the second target value is larger than the reference profile. For example, in the embodiment of FIG. 4, the second region (T2) is a region where the second target value of the target point exceeds the second target value of the reference profile based on the same first target value.

[0077] Here, the third region (T3) may be configured to be a region that exceeds a preset threshold for each of the plurality of target indicators. The threshold may be set independently for each of the first target value and the second target value. For example, in the embodiment of FIG. 4, the third region (T3) is a region where the first feature value of the target point exceeds the first threshold (th1) and the second feature value of the target point exceeds the second threshold (th2).

[0078] That is, in the embodiment of FIG. 4, the target point may be included in the reference profile, the first region (T1), the second region (T2), or the third region (T3).

[0079] The control unit (120) can be configured to diagnose the state of the battery based on the comparison result.

[0080] For example, the control unit (120) may be configured to diagnose the state of the battery as a positive / negative degeneration state when a target point representing a correspondence relationship between a plurality of target values ​​is included in the reference profile. Here, the positive / negative degeneration state is a state in which both the positive and negative electrodes of the battery are degenerated, and the degree of degeneration of the positive and negative electrodes is balanced.

[0081] As another example, the control unit (120) may be configured to diagnose the battery's condition as a negative degeneration state when the target point is included in the first region (T1) based on the reference profile. Here, the negative degeneration state is a state in which the degeneration of the battery's negative electrode is more dominant than the degeneration of the positive electrode. That is, the negative degeneration state is a state in which the degeneration of the positive and negative electrodes is not balanced, and the degeneration of the negative electrode has progressed more than the degeneration of the positive electrode. For example, the negative degeneration state is related to the loss of available lithium. If available lithium is lost, lithium plating (Li-plating), in which lithium metal is deposited on the surface of the negative electrode, may occur.

[0082] As another example, the control unit (120) may be configured to diagnose the state of the battery as positive degeneration state when the target point is included in the second region (T2) based on the reference profile. Here, the positive degeneration state is a state in which the positive electrode of the battery is degenerated, and the degeneration of the positive electrode is dominant over the degeneration of the negative electrode. That is, the positive degeneration state is a state in which the degeneration of the positive and negative electrodes is not balanced, and the degeneration of the positive electrode has progressed more than the degeneration of the negative electrode.

[0083] As another example, the control unit (120) may be configured to diagnose the battery's condition as an end-of-life (EOL) state when the target point is included in the third region (T3). Here, the EOL state refers to a state where the battery's degradation has progressed significantly and its use is not recommended. For example, the EOL state may be a state where the battery can be determined to be unusable.

[0084] A battery diagnostic device (100) according to one embodiment of the present invention can diagnose the state of a battery according to the corresponding relationship of target values ​​calculated in each of a plurality of sections. That is, according to one embodiment of the present invention, there is an advantage that the state of the battery can be diagnosed in various aspects depending on the combination of various target indicators.

[0085] In particular, since the target value for each section represents the state of the battery corresponding to that section, the state of the battery can be diagnosed more specifically by separating it based on the correspondence relationship of multiple target values.

[0087] Meanwhile, the profile acquisition unit (110) and the control unit (120) provided in the battery diagnostic device (100) may optionally include a processor, an ASIC (application-specific integrated circuit), another chipset, a logic circuit, a register, a communication modem, a data processing device, etc., known in the art, to execute various control logics performed in the present invention. Additionally, when the control logic is implemented in software, the profile acquisition unit (110) and the control unit (120) may be implemented as a set of program modules. At this time, the program modules may be stored in memory and executed by the profile acquisition unit (110) and the control unit (120). The memory may be located inside or outside the profile acquisition unit (110) and the control unit (120), and may be connected to the profile acquisition unit (110) and the control unit (120) by various well-known means.

[0088] Additionally, the battery diagnostic device (100) may further include a storage unit (130). The storage unit (130) may store data or programs necessary for each component of the battery diagnostic device (100) to perform operations and functions, or data generated during the process of performing operations and functions. The storage unit (130) is not limited in its type as long as it is a known information storage means capable of recording, erasing, updating, and reading data. As an example, the information storage means may include RAM, flash memory, ROM, EEPROM, registers, etc. Additionally, the storage unit (130) may store program codes in which processes executable by the profile acquisition unit (110) and the control unit (120) are defined.

[0089] For example, the storage unit (130) can store battery information, battery profile (BP), differential profile, and battery diagnostic information by the control unit (120).

[0091] The control unit (120) may be configured to control the battery based on the diagnosis result regarding the state of the battery. Specifically, the control unit (120) may change the usage conditions of the battery based on the diagnosis result.

[0092] The control unit (120) may be configured to reduce at least one of the upper limit C-rate and constant voltage charging time set for the battery when the battery condition is diagnosed as positive degeneration state or positive / negative degeneration state. That is, when the control unit (120) diagnoses that the positive electrode of the battery has degenerated, it may change the battery usage conditions to prevent further degeneration of the positive electrode of the battery.

[0093] The control unit (120) may be configured to reduce the charging upper limit voltage set for the battery when the battery condition is diagnosed as a negative degeneration state or a positive / negative degeneration state. When the control unit (120) is diagnosed as the negative electrode of the battery being degenerated, it may change the battery usage conditions to prevent further degeneration of the negative electrode of the battery.

[0094] As the usage conditions of the battery change, the degradation of the positive and / or negative electrodes of the battery can be slowed down, thereby increasing the expected lifespan of the battery.

[0096] The control unit (120) may be configured to divide the capacity range into a first range (R1) and a second range (R2) based on a preset division ratio or target capacity.

[0097] In one embodiment, the control unit (120) can divide the capacity range based on a preset ratio. For example, the control unit (120) can divide the capacity range in a ratio of n:m (where n and m are positive numbers) to set the lower capacity range as the first range (R1) and the upper capacity range as the second range (R2).

[0098] For example, assume that the starting capacity is Qi and the ending capacity is Qf. Also, assume that the capacity corresponding to the ratio of n:m is Qk, and Qk can be calculated according to the formula "(Qf-Qi)÷(n+m)×n". The control unit (120) can set the capacity range from Qi to Qk as the first range (R1). And, the control unit (120) can set the capacity range from Qk to Qf as the second range (R2).

[0099] In another embodiment, the control unit (120) can distinguish capacity ranges using a differential profile based on a battery profile (BP).

[0100] The profile acquisition unit (110) may be configured to further acquire a differential profile corresponding to the battery profile.

[0101] For example, if the battery profile (BP) is differentiated with respect to capacity, a differential profile representing the corresponding relationship between the differential voltage (dV / dQ) and the capacity (Q) can be generated. Conversely, if the battery profile (BP) is differentiated with respect to voltage, a differential profile representing the corresponding relationship between the differential capacity (dQ / dV) and the voltage (V) can be generated.

[0102] For example, the profile acquisition unit (110) can directly receive the differential profile of the battery from the outside. That is, the profile acquisition unit (110) can acquire the differential profile by receiving the differential profile through a wired and / or wireless connection to the outside.

[0103] As another example, the profile acquisition unit (110) can directly receive the battery profile (BP) of the battery from the outside. And, the profile acquisition unit (110) can generate a differential profile based on the battery profile (BP). That is, the profile acquisition unit (110) can receive the battery profile (BP) by being connected to the outside via wired and / or wireless connection, and can acquire the differential profile by directly generating the differential profile from the battery profile (BP).

[0104] As another example, the profile acquisition unit (110) can receive battery information regarding the voltage and capacity of the battery. Then, the profile acquisition unit (110) can generate a battery profile (BP) based on the received battery information and generate a differential profile based on the generated battery profile (BP). That is, the profile acquisition unit (110) can acquire a differential profile by directly generating a differential profile based on the battery information.

[0105] The profile acquisition unit (110) can be connected to communicate with the control unit (120). For example, the profile acquisition unit (110) can be connected to the control unit (120) via wired and / or wireless connections. The profile acquisition unit can transmit the acquired differential profile (DP) to the control unit (120).

[0107] In one embodiment, the differential profile (DP) obtained by the profile acquisition unit (110) may be configured to show a corresponding relationship between the battery capacity (Q) and the differential voltage (dV / dQ).

[0108] FIG. 5 is a schematic diagram illustrating a differential profile (DP) according to an embodiment of the present invention. In the embodiment of FIG. 5, the differential profile (DP) can be represented as an XY graph in which the X-axis is set as capacitance (Q) and the Y-axis is set as differential voltage (dV / dQ). For example, the differential profile (DP) of FIG. 5 has the same shape as the first differential profile of FIG. 3.

[0109] The control unit (120) can be configured to determine the main peak (tp) in the differential profile (DP).

[0110] Specifically, the control unit (120) may be configured to determine a plurality of local minima in the differential profile (DP). For example, in the embodiment of FIG. 5, the differential profile (DP) may include first to fifth local minima (p1, p2, p3, p4, p5).

[0111] And, the control unit (120) can be configured to determine the minimum point with the smallest corresponding differential voltage among the determined minimum points as the main peak (tp). For example, in the embodiment of FIG. 5, since the differential voltage corresponding to the third minimum point (p3) among the multiple minimum points (p1, p2, p3, p4, p5) is the smallest, the control unit (120) can determine the third minimum point (p3) as the main peak (tp).

[0112] The control unit (120) may be configured to divide the capacity range based on the capacity of the determined main peak (tp). For example, in the embodiment of FIG. 5, if the capacity of the main peak (tp) is Qk, the control unit (120) may divide the capacity range into a first range (R1) of Qi to Qk and a second range (R2) of Qk to Qf.

[0113] Generally, based on the minimum point where the differential voltage is smallest, the low-capacity side reflects the state of the negative electrode of the battery, and the high-capacity side reflects the state of the positive electrode of the battery. Therefore, the control unit (120) can distinguish the capacity range of the battery based not only on a certain ratio (n:m) but also on the main peak (tp).

[0115] More preferably, the control unit (120) can determine the minimum point with the smallest corresponding differential voltage, which is included in the middle or lower capacity range of the battery, as the main peak (tp).

[0116] Generally, if the capacity range of the battery is divided into a low-capacity range and a high-capacity range, the minimum point with the smallest differential voltage is included in the low-capacity range. Therefore, the control unit (120) can determine the main peak (tp) in the battery's mid-to-low capacity range (low-capacity range). That is, by determining the main peak (tp) among a plurality of minimum points included in the low-capacity range, the control unit (120) can save the time and system resources required to determine the main peak (tp).

[0117] For example, in the embodiment of FIG. 5, the low-capacity section includes first to third minimum points (p1, p2, p3). The control unit (120) can determine the third minimum point (p3), which has the smallest differential voltage among the first to third minimum points (p1, p2, p3), as the main peak (tp).

[0118] In other words, since the total capacity range and the low capacity range differ in the number of included local minimums, the time required to compare the differential voltages of multiple local minimums and the system resources involved may also differ. Therefore, the control unit can determine the main peak more quickly by considering only the local minimums included in the low capacity range.

[0120] In another embodiment, the differential profile obtained by the profile acquisition unit (110) may be configured to show a correspondence between the voltage (V) of the battery and the differential capacity (dQ / dV).

[0121] The control unit (120) may be configured to determine a plurality of maximum points in the differential profile. A maximum point is a concept opposite to a minimum point and refers to a point in the differential profile that has an upwardly convex shape.

[0122] And, the control unit (120) can be configured to determine the maximum point with the largest corresponding differential capacity among the determined maximum points as the main peak.

[0124] The battery diagnostic device (100) according to the present invention may be applied to a Battery Management System (BMS). That is, the BMS according to the present invention may include the battery diagnostic device (100) described above. In this configuration, at least some of the components of the battery diagnostic device (100) may be implemented by supplementing or adding the functions of the components included in a conventional BMS. For example, the profile acquisition unit (110), control unit (120), and storage unit (130) of the battery diagnostic device (100) may be implemented as components of the BMS.

[0125] In addition, 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 battery diagnostic device (100) described above and one or more battery cells. In addition, the battery pack may further include electrical components (relays, fuses, etc.) and a case, etc.

[0126] FIG. 6 is a schematic diagram illustrating a battery pack (10) according to another embodiment of the present invention.

[0127] The positive terminal of the battery (11) can be connected to the positive terminal (P+) of the battery pack (10), and the negative terminal of the battery (11) can be connected to the negative terminal (P-) of the battery pack (10).

[0128] The measuring unit (12) can be connected to the first sensing line (SL1), the second sensing line (SL2), and the third sensing line (SL3). Specifically, the measuring unit (12) can be connected to the positive terminal of the battery (11) through the first sensing line (SL1) and to the negative terminal of the battery (11) through the second sensing line (SL2). The measuring unit (12) can measure the voltage of the battery (11) based on the voltage measured at each of the first sensing line (SL1) and the second sensing line (SL2).

[0129] Additionally, the measuring unit (12) can be connected to a current measuring unit (A) through a third sensing line (SL3). For example, the current measuring unit (A) may be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of the battery (11). The measuring unit (12) can calculate the charging amount by measuring the charging current of the battery (11) through the third sensing line (SL3). Furthermore, the measuring unit (12) can calculate the discharging amount by measuring the discharging current of the battery (11) through the third sensing line (SL3).

[0130] For example, the profile acquisition unit (110)(110) can receive battery information regarding the voltage and current of the battery from the measurement unit (12). Then, the profile acquisition unit (110)(110) can generate a battery profile (BP) and a differential profile based on the battery information.

[0131] As another example, the profile acquisition unit (110)(110) can receive a battery profile (BP) from the measurement unit (12). Then, the profile acquisition unit (110)(110) can generate a differential profile based on the battery profile (BP).

[0132] As another example, the profile acquisition unit (110) (110) can receive a differential profile from the measurement unit (12).

[0133] An external device may be connected to the positive terminal (P+) and the negative terminal (P-) of the battery pack (10). For example, the external device may be a charging device or a load. Also, the positive terminal of the battery (11), the positive terminal (P+) of the battery pack (10), the external device, the negative terminal (P-) of the battery pack (10), and the negative terminal of the battery (11) may be electrically connected.

[0135] FIG. 7 is a schematic drawing illustrating a vehicle (700) according to another embodiment of the present invention.

[0136] Referring to FIG. 7, a battery pack (710) according to an embodiment of the present invention may be included in a vehicle (700), such as an electric vehicle (EV) or a hybrid vehicle (HV). The battery pack (710) can drive the vehicle (700) by supplying power to a motor through an inverter provided in the vehicle (700). Here, the battery pack (710) may include a battery diagnostic device (100). That is, the vehicle (700) may include a battery diagnostic device (100). In this case, the battery diagnostic device (100) may be an on-board device included in the vehicle (700).

[0138] FIG. 8 is a schematic diagram illustrating a battery diagnostic method according to another embodiment of the present invention.

[0139] Referring to FIG. 8, the battery diagnostic method may include a profile acquisition step (S100), a segment division step (S200), a target value derivation step (S300), a comparison step (S400), and a diagnostic step (S500).

[0140] Preferably, each step of the battery diagnostic method can be performed by a battery diagnostic device (100). For convenience of explanation, details that overlap with previously described content will be omitted or briefly explained below.

[0141] The profile acquisition step (S100) is a step of acquiring a battery profile (BP) that represents the corresponding relationship between the voltage and capacity of the battery, and can be performed by the profile acquisition unit (110).

[0142] For example, the profile acquisition unit (110) can directly receive the battery profile (BP) of the battery from the outside. That is, the profile acquisition unit (110) can acquire the battery profile (BP) by receiving the battery profile (BP) through a wired and / or wireless connection with the outside.

[0143] As another example, the profile acquisition unit (110) can receive battery information regarding the voltage and capacity of the battery. Then, the profile acquisition unit (110) can generate a battery profile (BP) based on the received battery information. That is, the profile acquisition unit (110) can acquire a battery profile (BP) by directly generating a battery profile (BP) based on the battery information.

[0144] The section division step (S200) is a step of dividing the capacity section of the battery profile (BP) into multiple sections, and can be performed by the control unit (120).

[0145] Specifically, the control unit (120) can divide the entire capacity range of the battery profile (BP) into two or more ranges. For example, in the embodiment of FIG. 2, the capacity range of the battery profile (BP) is Qi to Qf. The control unit (120) can divide the capacity range of Qi to Qf into a first range (R1) and a second range (R2) based on Qk.

[0146] The target value derivation step (S300) is a step of deriving a target value for one of the multiple diagnostic indicators pre-set in each section that is related to the differential capacity peak, and can be performed by the control unit (120).

[0147] For example, in the embodiment of FIG. 3, the control unit (120) can select a target indicator for each of the first section (R1) and the second section (R2). And, the control unit (120) can derive a target value corresponding to the selected target indicator.

[0148] The comparison step (S400) is a step of comparing the correspondence relationship between the derived multiple target values ​​with a preset reference profile that represents the correspondence relationship between the multiple target indicators, and can be performed by the control unit (120).

[0149] Specifically, it is assumed that the capacity range of the battery profile (BP) is divided into a first range (R1) and a second range (R2), that a first target value for a target indicator is derived in the first range (R1), and that a second target value for a target indicator is derived in the second range (R2). The control unit (120) can compare a target point representing a correspondence relationship of a plurality of target values ​​with a reference profile.

[0150] For example, in the embodiment of FIG. 4, the control unit (120) can determine whether the target point is included in the reference profile. If the target point is not included in the reference profile, the control unit (120) can determine which of the first area (T1), the second area (T2), and the third area (T3) the target point is included in.

[0151] The diagnosis step (S500) is a step of diagnosing the state of the battery based on the comparison result, and can be performed by the control unit (120).

[0152] For example, in the embodiment of FIG. 4, the control unit (120) can diagnose the state of the battery as positive / negative degeneration state when the target point is included in the reference profile.

[0153] As another example, the control unit (120) can diagnose the state of the battery as negative degeneration state when the target point is included in the first region (T1).

[0154] As another example, the control unit (120) can diagnose the state of the battery as positive degradation state when the target point is included in the second region (T2).

[0155] As another example, the control unit (120) can diagnose the battery's state as EOL if the target point is included in the third region (T3).

[0157] The embodiments of the present invention described above are not limited to implementation through devices and methods, but may also be implemented through a program that realizes a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which such a program is recorded. Such implementation can be easily achieved by a person skilled in the art to which the present invention pertains, based on the description of the embodiments described above.

[0158] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0159] Furthermore, since the present invention described above allows for various substitutions, modifications, and changes within the scope of the technical concept of the present invention to those skilled in the art without departing from the technical spirit of the present invention, it is not limited by the aforementioned embodiments and attached drawings, but rather all or part of each embodiment may be selectively combined to allow for various modifications. Explanation of the symbols

[0160] 10: Battery pack 11: Battery 12: Measurement section 100: Battery Diagnostic Device 110: Profile Acquisition Section 120: Control unit 130: Storage section 700: Car 710: Battery pack

Claims

Claim 1 A battery diagnostic device characterized by comprising: a profile acquisition unit configured to acquire a battery profile representing a correspondence relationship between the voltage and capacity of a battery; and a control unit configured to divide the capacity range of the battery profile into a plurality of ranges, determine one target indicator related to a differential capacity peak among a plurality of pre-set diagnostic indicators in each range, derive a target value for the target indicator determined for each range, compare the correspondence relationship between the derived plurality of target values ​​with a reference profile pre-set to represent the correspondence relationship between the target indicators determined for each range, and diagnose the state of the battery according to the comparison result. Claim 2 A battery diagnostic device according to claim 1, wherein the control unit is configured to determine, for each of the above sections, the number of multiple differential capacity peaks included in a differential profile corresponding to the battery profile and representing a corresponding relationship between voltage and differential capacity, the voltage of the main peak among the multiple differential capacity peaks, or the differential capacity of the main peak as the target indicator. Claim 3 A battery diagnostic device according to claim 1, wherein the control unit is configured to diagnose the state of the battery as positive / negative degeneration state when a target point representing a correspondence relationship between the plurality of target values ​​is included in the reference profile, diagnose the state of the battery as negative degeneration state when the target point is included in a first region based on the reference profile, and diagnose the state of the battery as positive degeneration state when the target point is included in a second region based on the reference profile. Claim 4 A battery diagnostic device according to claim 3, wherein the control unit is configured to diagnose the state of the battery as an EOL (End of life) state when the target point is included in the third region, and the third region is configured to be a region that exceeds a preset threshold value for each of the plurality of target indicators. Claim 5 A battery diagnostic device according to paragraph 3, wherein the control unit is configured to reduce at least one of the upper limit C-rate and constant voltage charging time set for the battery when the state of the battery is diagnosed as the positive degeneration state or the positive / negative degeneration state. Claim 6 A battery diagnostic device according to paragraph 3, wherein the control unit is configured to reduce the charging upper limit voltage set for the battery when the state of the battery is diagnosed as the negative degeneration state or the positive / negative degeneration state. Claim 7 A battery diagnostic device according to claim 1, wherein the control unit is configured to divide the capacity range into a first range and a second range based on a preset division ratio or target capacity. Claim 8 A battery diagnostic device according to claim 7, wherein the profile acquisition unit is configured to further acquire a differential profile corresponding to the battery profile, and the control unit is configured to determine a main peak in the differential profile and to distinguish the capacity range based on the capacity of the determined main peak. Claim 9 A battery diagnostic device according to claim 8, wherein the differential profile is configured to represent a corresponding relationship between the capacity of the battery and the differential voltage, and the control unit is configured to determine a plurality of local minimums in the differential profile and determine the local minimum with the smallest corresponding differential voltage among the determined plurality of local minimums as the main peak. Claim 10 A battery diagnostic device according to claim 8, wherein the differential profile is configured to represent a corresponding relationship between the voltage and differential capacity of the battery, and the control unit is configured to determine a plurality of maximum points in the differential profile and determine the maximum point with the largest corresponding differential capacity among the determined plurality of maximum points as the main peak. Claim 11 A battery pack characterized by including a battery diagnostic device according to any one of claims 1 to 10. Claim 12 An automobile characterized by including a battery diagnostic device according to any one of claims 1 to 10. Claim 13 A battery diagnosis method characterized by comprising: a profile acquisition step in which a battery profile representing a correspondence relationship between the voltage and capacity of a battery is acquired in a profile acquisition unit; a section division step in which a capacity section of the battery profile is divided into a plurality of sections in a control unit; a target value derivation step in which a target indicator related to a differential capacity peak is determined among a plurality of diagnostic indicators pre-set in each section and a target value for the target indicator determined for each section is derived; a comparison step in which a reference profile pre-set to represent a correspondence relationship between the derived plurality of target values ​​is compared with a reference profile in which a correspondence relationship between the target indicators determined for each section is derived in the control unit; and a diagnosis step in which the state of the battery is diagnosed according to the comparison result in the control unit.

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