Apparatus and method for diagnosing battery

Abstract

An apparatus for diagnosing a battery, according to one embodiment of the present invention, comprises: a profile acquisition unit for acquiring a differential profile indicating a correspondence relationship between the voltage and the differential capacity of a battery; a profile correction unit which determines a target current rate (C-rate) corresponding to the differential profile, and which corrects the differential profile on the basis of an overvoltage profile corresponding to the target C-rate, so as to generate a correction profile; and a control unit which determines a first target peak and a second target peak in the correction profile, and which diagnoses the state of the battery on the basis of the behavior of the first target peak and the behavior of the second target peak.

Description

Battery diagnostic device and method

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0012287, filed January 26, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a battery diagnostic device and method, and more particularly, to a battery diagnostic device and method for diagnosing the state of a battery.

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

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

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

[0006] The present invention provides a battery diagnostic device and method for diagnosing the current state of a battery.

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

[0008] A battery diagnosis device according to one aspect of the present invention may include a profile acquisition unit configured to acquire a differential profile indicating a correspondence between a capacity of a battery and a differential voltage; a profile correction unit configured to determine a target C-rate (Current-rate) corresponding to the differential profile and generate a correction profile by correcting the differential profile based on an overvoltage profile corresponding to the target C-rate; and a control unit configured to diagnose a state of the battery based on a shape of a target capacity section of the correction profile.

[0009] The control unit may be configured to determine a minimum point with a minimum corresponding capacity among a plurality of minimum points included in the correction profile as a target peak, and set the target capacity section based on a target differential voltage corresponding to the target peak.

[0010] The control unit may be configured to determine a reference point closest to the target peak, corresponding to the target differential voltage in the correction profile, and set a capacity section from the target peak to the reference point as the target capacity section.

[0011] The control unit may be configured to set the differential voltage corresponding to the second minimum point as the target differential voltage when the differential capacity of the target peak is smaller than the differential capacity of the second minimum point having the second smallest corresponding capacity among the plurality of minimum points.

[0012] The control unit may be configured to determine a reference point that corresponds to the target differential voltage in the correction profile and is closest to the second minimum point, and to set a capacity section from the reference point to the second minimum point as the target capacity section.

[0013] The control unit may be configured to divide the target capacity section into a low capacity section and a high capacity section, and to diagnose the state of the battery based on the section to which the characteristic point with the largest corresponding differential voltage belongs in the target capacity section.

[0014] The control unit may be configured to diagnose the state of the battery as a state of available lithium loss when the characteristic point falls within the high-capacity range.

[0015] The above profile correction unit may be configured to generate the correction profile by calculating the difference between the differential profile and the overvoltage profile.

[0016] The above overvoltage profile can be configured to be pre-saved for each of a plurality of C-rates.

[0017] The above profile correction unit may be configured to select an overvoltage profile corresponding to the target C-rate from among a plurality of pre-stored overvoltage profiles.

[0018] The above overvoltage profile can be preset based on a reference differential profile of the reference battery for the reference C-rate and a target differential profile of the reference battery for the target C-rate.

[0019] The above overvoltage profile can be preset to represent the difference between the reference differential profile and the target differential profile.

[0020] 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.

[0021] A vehicle according to another aspect of the present invention may include a battery diagnostic device according to one aspect of the present invention.

[0022] A battery diagnosis method according to another aspect of the present invention may include a profile acquisition step of acquiring a differential profile indicating a correspondence between a capacity of a battery and a differential voltage; a target determination step of determining a target C-rate corresponding to the differential profile; a correction profile generation step of generating a correction profile by correcting the differential profile based on an overvoltage profile corresponding to the target C-rate; and a battery diagnosis step of diagnosing a state of the battery based on a modification of a target capacity section of the correction profile.

[0023] A battery diagnosis method according to another aspect of the present invention may further include a target peak determination step of determining a minimum point with a minimum corresponding capacity among a plurality of minimum points included in the correction profile as a target peak, and setting the target capacity range based on a target differential voltage corresponding to the target peak.

[0024] The above target peak determination step may include a step of determining a reference point closest to the target peak corresponding to the target differential voltage in the correction profile, and setting a capacity section from the target peak to the reference point as the target capacity section.

[0025] According to another aspect of the present invention, a non-transitory readable storage medium may be a non-transitory readable storage medium storing a program for executing a battery diagnosis method, the method comprising: a profile acquisition step of acquiring a differential profile indicating a correspondence between a capacity of a battery and a differential voltage; a target determination step of determining a target C-rate corresponding to the differential profile; a correction profile generation step of generating a correction profile by correcting the differential profile based on an overvoltage profile corresponding to the target C-rate; and a battery diagnosis step of diagnosing a state of the battery based on a shape of a target capacity section of the correction profile.

[0026] According to another aspect of the present invention, a non-transitory readable storage medium may be a non-transitory readable storage medium storing a program for executing a battery diagnosis method, which further includes a target peak determination step of determining a minimum point having a minimum corresponding capacity among a plurality of minimum points included in the correction profile as a target peak and setting the target capacity range based on a target differential voltage corresponding to the target peak.

[0027] According to one aspect of the present invention, since the state of the battery is diagnosed through a correction profile, the state of the battery can be diagnosed relatively quickly.

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

[0029] The following drawings attached to this specification serve to further understand the technical idea of ​​the present invention together with the detailed description of the invention described below, and therefore the present invention should not be interpreted as being limited to the matters described in such drawings.

[0030] FIG. 1 is a schematic diagram illustrating a battery diagnostic device according to one embodiment of the present invention.

[0031] FIG. 2 is a diagram schematically illustrating a battery profile according to one embodiment of the present invention.

[0032] FIG. 3 is a schematic diagram illustrating a differential profile according to one embodiment of the present invention.

[0033] FIG. 4 is a diagram schematically illustrating a differential profile and a correction profile according to one embodiment of the present invention.

[0034] FIG. 5 is a drawing schematically illustrating a correction profile according to one embodiment of the present invention.

[0035] FIG. 6 is a schematic diagram illustrating a plurality of correction profiles for a first battery according to one embodiment of the present invention.

[0036] FIG. 7 is a diagram schematically illustrating the state of a battery corresponding to a plurality of correction profiles for a second battery according to one embodiment of the present invention.

[0037] FIG. 8 is a schematic drawing of a battery pack according to another embodiment of the present invention.

[0038] FIG. 9 is a schematic drawing of a vehicle according to another embodiment of the present invention.

[0039] FIG. 10 is a diagram schematically illustrating a battery diagnosis method according to another embodiment of the present invention.

[0040] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best possible manner.

[0041] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0042] In addition, when describing the present invention, if it is determined that the description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

[0043] Terms that include ordinal numbers, such as first, second, etc., are used to distinguish one of the various components from the rest, and are not used to limit the components by such terms.

[0044] Throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

[0045] Additionally, throughout the specification, when we say that a part is "connected" to another part, this includes not only cases where it is "directly connected" but also cases where it is "indirectly connected" with other elements in between.

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

[0047] Referring to FIG. 1, the battery diagnostic device (100) may include a profile acquisition unit (110), a profile correction unit (120), a control unit (130), and a storage unit (140).

[0048] A battery may refer to a physically separate, independent cell, having a negative terminal and a positive terminal. For example, a lithium-ion battery or a lithium polymer battery may be considered a battery. Furthermore, the battery may be cylindrical, prismatic, or pouch-shaped. 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 convenience of explanation, the term "battery" will be described herein as referring to a single, independent cell.

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

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

[0051] FIG. 2 is a schematic diagram illustrating a battery profile (BP) according to one embodiment of the present invention. In the embodiment of FIG. 2, the battery profile (BP) can be expressed as an XY graph in which the X-axis is set to capacity (Q) and the Y-axis is set to voltage (V).

[0052] And, when the battery profile (BP) is differentiated with respect to the capacity, a differential profile (DP) can be generated that represents the correspondence between the differential voltage (dV / dQ) and the capacity (Q).

[0053] Fig. 3 is a schematic diagram illustrating a differential profile (DP) according to one embodiment of the present invention. In the embodiment of Fig. 3, the differential profile (DP) can be expressed as an XY graph in which the X-axis is set to the capacity (Q) and the Y-axis is set to the differential voltage (dV / dQ).

[0054] For example, there are no specific restrictions on the current rate (C-rate) during charging or discharging for generating a battery profile (BP). In one embodiment, the battery can be charged or discharged at a low rate to obtain a more accurate battery profile (BP) and differential profile (DP). For example, a battery profile (BP) can be generated during the process of charging or discharging the battery at a relatively low rate, such as 0.05C.

[0055] In one embodiment, the profile acquisition unit (110) can directly receive the differential profile (DP) of the battery from an external source. For example, the profile acquisition unit (110) can acquire the differential profile (DP) by being connected to the external source via wire and / or wirelessly and receiving the differential profile (DP).

[0056] As another example, the profile acquisition unit (110) may receive a battery profile (BP) of a battery from the outside, and directly generate a differential profile (DP) by differentiating the received battery profile (BP) with respect to capacity. According to one embodiment, the profile acquisition unit (110) may be connected to the outside via wires and / or wirelessly to receive the battery profile (BP), and directly generate the differential profile (DP) from the received battery profile (BP), thereby obtaining the differential profile (DP).

[0057] As another example, the profile acquisition unit (110) receives battery information about the voltage and capacity of the battery from the outside, directly generates a battery profile (BP) based on the received battery information, and can also directly generate a differential profile (DP) based on the generated battery profile (BP).

[0058] According to one embodiment, the profile acquisition unit (110) may be connected to the control unit (130) so as to be communicable. For example, the profile acquisition unit (110) may be connected to the control unit (130) via wire and / or wirelessly. The profile acquisition unit may transmit the acquired differential profile (DP) to the control unit (130).

[0059] According to one embodiment, the profile correction unit (120) may be configured to determine a target C-rate corresponding to a differential profile (DP).

[0060] According to one embodiment, the profile correction unit (120) can obtain information about a target C-rate corresponding to a differential profile (DP) from the profile acquisition unit (110).

[0061] For example, when the battery is charged at 0.33 C, the target C-rate corresponding to the differential profile (DP) may be 0.33 C. The profile correction unit (120) may receive information about the differential profile (DP) and 0.33 C from the profile acquisition unit (110). Then, the profile correction unit (120) may determine 0.33 C corresponding to the differential profile (DP) as the target C-rate.

[0062] The profile correction unit (120) can be configured to generate a correction profile (CP) by correcting a differential profile (DP) based on an overvoltage profile corresponding to a target C-rate.

[0063] In one embodiment, the overvoltage profile may be preset to represent an overvoltage portion included in a differential profile (DP). For example, the overvoltage profile may be preset based on a reference differential profile (DP) of a reference battery for a reference C-rate and a target differential profile (DP) of the reference battery for a target C-rate. In one embodiment, the target C-rate may be set to be greater than the reference C-rate. Additionally, the overvoltage profile may be preset to represent a capacity-dependent differential voltage difference between the reference differential profile (DP) and the target differential profile (DP).

[0064] For example, when the reference C-rate is 0.05C and the target C-rate is 0.33C, when the reference battery is charged (or discharged) at 0.05C, a reference battery profile (BP) for the reference C-rate can be acquired, and a reference differential profile (DP) can be acquired based on the reference battery profile (BP). Then, when the reference battery is charged (or discharged) at 0.33C, a target battery profile (BP) for the target C-rate can be acquired, and a target differential profile (DP) can be acquired based on the target battery profile (BP). Then, an overvoltage profile corresponding to a C-rate of 0.33C can be generated based on the difference between the reference differential profile (DP) and the target differential profile (DP). When the battery is charged (or discharged) at a target C-rate greater than the reference C-rate, an overvoltage may be included in the measured voltage of the battery. Accordingly, the profile correction unit (120) can generate an overvoltage profile by removing the reference differential profile (DP) based on the reference C-rate from the target differential profile (DP) based on the target C-rate.

[0065] In addition, the profile correction unit (120) can be configured to select an overvoltage profile corresponding to the target C-rate from among a plurality of pre-stored overvoltage profiles.

[0066] Overvoltage profiles can be configured to be pre-saved for each of multiple C-rates.

[0067] In one embodiment, multiple overvoltage profiles may be provided, and the C-rates corresponding to each of the multiple overvoltage profiles may be different. For example, based on a unit C-rate, an overvoltage profile corresponding to each C-rate may be stored in advance.

[0068] In addition, an overvoltage profile for a C-rate that has not been experimentally obtained can be obtained and stored through interpolation or extrapolation between similar overvoltage profiles. For example, the profile correction unit (120) can generate overvoltage profiles for various C-rates in addition to the pre-stored overvoltage profiles through interpolation or extrapolation, and store the generated overvoltage profiles in the storage unit (140). For example, when an overvoltage profile corresponding to a C-rate of 1C and an overvoltage profile corresponding to a C-rate of 1.2C are pre-stored, an overvoltage profile corresponding to a C-rate of 1.1C can be further obtained based on the difference between the two overvoltage profiles.

[0069] The profile correction unit (120) can be configured to generate a correction profile (CP) by calculating the difference between the differential profile (DP) and the overvoltage profile.

[0070] For example, the profile correction unit (120) can generate a correction profile (CP) by calculating the difference between the differential profile (DP) and the overvoltage profile in the same way that the overvoltage profile is generated based on the difference between the reference differential profile (DP) and the target differential profile (DP).

[0071] Alternatively, the profile correction unit (120) can generate a correction profile (CP) by calculating the voltage-dependent differential capacity difference between the differential profile (DP) and the overvoltage profile.

[0072] FIG. 4 is a schematic diagram illustrating a differential profile (DP) and a correction profile (CP) according to one embodiment of the present invention. FIG. 5 is also a schematic diagram illustrating a correction profile (CP) according to one embodiment of the present invention.

[0073] In the embodiment of FIG. 4, the correction profile (CP) can be generated based on the differential voltage difference by capacity of the overvoltage profile (not shown) corresponding to the differential profile (DP). According to one embodiment, the profile correction unit (120) can generate a correction profile (CP) from which the overvoltage portion included in the differential profile (DP) is removed by calculating the difference between the differential profile (DP) and the overvoltage profile.

[0074] The control unit (130) may be configured to diagnose the condition of the battery based on the modification of the target capacity section (TR) of the correction profile (CP). Here, the target capacity section (TR) is a capacity section in which the condition of the battery can be diagnosed based on the modification, and an embodiment in which the control unit (130) sets the target capacity section (TR) will be described later.

[0075] Referring to FIG. 5, the control unit (130) can diagnose the state of the battery based on whether the target capacity section (TR) has changed in shape. For example, the control unit (130) can determine whether the target capacity section (TR) has changed in shape and diagnose the state of the battery in response to the determination result.

[0076] For example, the control unit (130) can diagnose whether the battery has lost available lithium. For example, if the control unit (130) determines that the shape of the target capacity section (TR) has changed, the control unit can diagnose the battery's state as a state of available lithium loss.

[0077] Here, the available lithium loss state refers to a state in which the amount of lithium involved in the battery's charge and discharge has been lost compared to the initial state due to various causes. For example, the lost lithium can precipitate as lithium metal on the battery's negative electrode surface. This phenomenon is called lithium plating. If lithium plating becomes severe, it can cause short circuits within the battery, leading to unexpected and serious problems such as fire or explosion.

[0078] A battery diagnosis device (100) according to one embodiment of the present invention can relatively quickly derive a correction profile (CP) that can diagnose the state of a battery using an overvoltage profile. In addition, since the battery diagnosis device (100) can diagnose the state of a battery only by modifying a target capacity section (TR) in the correction profile (CP), the state of the battery can be diagnosed more quickly. According to the present invention, since the loss of available lithium in a battery can be quickly diagnosed, unexpected accidents due to lithium plating can be prevented or suppressed in advance.

[0079] Meanwhile, the profile acquisition unit (110), the profile correction unit (120), and the control unit (130) provided in the battery diagnosis device (100) may optionally include a processor, an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a register, a communication modem, a data processing device, etc. known in the art to execute various control logics performed in the present invention. In addition, when the control logic is implemented in software, the profile correction unit (120) may be implemented as a set of program modules. At this time, the program modules may be stored in a memory and executed by the profile acquisition unit (110), the profile correction unit (120), and the control unit (130). The memory may be located inside or outside the profile acquisition unit (110), the profile correction unit (120), and the control unit (130), and may be connected to the profile acquisition unit (110), the profile correction unit (120), and the control unit (130) by various well-known means.

[0080] In addition, the battery diagnostic device (100) may further include a storage unit (140). The storage unit (140) may store data or programs required for each component of the battery diagnostic device (100) to perform operations and functions, or data generated in the process of performing operations and functions. The storage unit (140) is not particularly limited in type as long as it is a known information storage means known to be able to record, erase, update, and read data. As an example, the information storage means may include a RAM (Random Access Memory), a flash memory, a ROM (Read-Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), a register, etc. In addition, the storage unit (140) may store program codes defining processes executable by the profile acquisition unit (110), the profile correction unit (120), and the control unit (130).

[0081] The storage unit (140) can store a battery profile (BP), a differential profile (DP), and a correction profile (CP).

[0082] Below, an embodiment in which the control unit (130) diagnoses the state of the battery is described together with an embodiment.

[0083] The control unit (130) can be configured to divide the target capacity section (TR) into a low capacity section and a high capacity section.

[0084] In one embodiment, the control unit (130) can divide the target capacity section (TR) into low-capacity sections and high-capacity sections. For example, the section sizes (capacity range sizes) of the low-capacity section and the high-capacity section are identical. Here, the section size represents the difference between the upper and lower capacity limits of the section, and is a different factor from the area of ​​the section.

[0085] For example, it is assumed that the target capacity section (TR) is a capacity section from Qn to Qm. The control unit (130) can set the capacity section from Qn to (Qm-Qn) / 2 as a low capacity section, and set the capacity section from (Qm-Qn) / 2 to Qm as a high capacity section.

[0086] FIG. 6 is a schematic diagram illustrating multiple correction profiles (CP) for a first battery according to one embodiment of the present invention. For example, FIG. 6 is a diagram illustrating multiple correction profiles (CP) for a first battery in which available lithium is lost as the cycle progresses. For example, FIG. 6 is a diagram illustrating correction profiles (CP) corresponding to the first cycle (ini), the 10th cycle, the 40th cycle, the 60th cycle, and the 90th cycle of the first battery.

[0087] In the embodiment of Fig. 6, the target capacity section (TR) can be divided into a low capacity section (LQ) and a high capacity section (HQ). Here, the section size of the low capacity section (LQ) and the section size of the high capacity section (HQ) are the same.

[0088] According to one embodiment, the control unit (130) may be configured to diagnose the state of the battery based on the section to which the characteristic point with the largest corresponding differential voltage belongs in the target capacity section (TR).

[0089] Here, the characteristic point is a point belonging to the target capacity section (TR), and means the point where the corresponding differential voltage is the largest.

[0090] For example, the control unit (130) may be configured to diagnose the battery's condition as a state of available lithium loss if the characteristic point falls within the high-capacity range. For example, if the profile shape has changed to the extent that the characteristic point is located within the high-capacity range due to loss of available lithium in the battery, the control unit (130) may diagnose the battery's condition as a state of available lithium loss.

[0091] As another example, if the characteristic point falls within the low-capacity range, the control unit (130) may diagnose the battery's condition as a state in which available lithium is not lost. Here, since the characteristic point gradually moves toward the high-capacity side as available lithium is lost, even if the characteristic point falls within the low-capacity range, some of the battery's available lithium may be lost. According to one embodiment, the control unit (130) may diagnose the battery's condition by ignoring losses that do not change the profile shape, even if some of the available lithium is lost compared to the initial level.

[0092] For example, in the embodiment of FIG. 6, in the initial cycle (ini), the characteristic point belongs to the low-capacity section (LQ), but in the 60th and 90th cycles, the characteristic point belongs to the high-capacity section (HQ). In this way, as the cycle progresses, the highest differential voltage of the low-capacity section (LQ) decreases, and the highest differential voltage of the high-capacity section (HQ) decreases. Consequently, the profile shape itself may change due to the loss of available lithium. Therefore, according to one embodiment, the control unit (130) may diagnose whether the battery has lost available lithium based on the section to which the characteristic point belongs.

[0093] The target capacity range (TR) is a capacity that primarily reflects the condition of the battery's negative electrode. Therefore, if the battery's available lithium is lost, the profile changes most significantly within the target capacity range (TR). For example, the location of the feature point with the highest differential voltage within the target capacity range (TR) changes the most.

[0094] For example, in the calibration profile (CP) of a battery in the beginning of life (BOL) state, the characteristic points are included in the low-capacity section of the target capacity section (TR). However, in the calibration profile (CP) of a battery with a significant loss of available lithium, the characteristic points are included in the high-capacity section of the target capacity section (TR). In this way, as the available lithium is lost, the characteristic points move from the low-capacity section to the high-capacity section of the target capacity section (TR). Therefore, the battery diagnosis device (100) can quickly diagnose the state of the battery by considering the peculiar behavior of the characteristic points according to the loss of the available lithium of the battery.

[0095] FIG. 7 is a diagram schematically illustrating the state of a battery corresponding to a plurality of correction profiles (CP) for a second battery according to an embodiment of the present invention. FIG. 7 is a diagram illustrating a plurality of correction profiles (CP) for a second battery with a loss of positive electrode capacity. For example, FIG. 7 is a diagram illustrating correction profiles (CP) corresponding to the first cycle (ini), the 10th cycle, the 20th cycle, the 30th cycle, the 40th cycle, the 50th cycle, the 60th cycle, the 70th cycle, the 80th cycle, and the 90th cycle of the second battery.

[0096] Unlike the embodiment of FIG. 6, in the embodiment of FIG. 7, feature points belonging to the target capacity section (TR) remain in the low capacity section (LQ) even as the cycle progresses. For example, if a battery has not lost available lithium, the profile deformation of the target capacity section (TR) will not change even if it deteriorates due to other causes (e.g., cathode capacity loss). Therefore, the battery diagnostic device (100) can quickly diagnose whether the battery is in a state of available lithium loss based on the available lithium loss and the specific behavior of the feature points.

[0097] Next, an embodiment in which the control unit (130) sets a target capacity section (TR) is described.

[0098] The control unit (130) may be configured to determine the minimum point with the minimum corresponding capacity among the minimum points included in the correction profile (CP) as the target peak (tp).

[0099] According to one embodiment, the correction profile (CP) may include multiple local minimum points. The control unit (130) may determine the local minimum point with the smallest corresponding capacity among the multiple local minimum points included in the correction profile (CP) as the target peak (tp).

[0100] For example, in the embodiment of FIG. 5, the correction profile (CP) may include a first minimum point (p1), a second minimum point (p2), a third minimum point (p3), and a fourth minimum point (p4). Since the capacity corresponding to the first minimum point (p1) is the smallest among the first to fourth minimum points (p4), the control unit (130) may determine the first minimum point (p1) as the target peak (tp).

[0101] The control unit (130) may be configured to set a target capacity section (TR) based on a target differential voltage corresponding to a target peak (tp).

[0102] According to one embodiment, the control unit (130) may be configured to determine a reference point (rp) that corresponds to a target differential voltage in the compensation profile (CP) and is closest to the target peak (tp).

[0103] In general, in a differential profile (DP) representing a correspondence between a battery's capacity and a differential voltage, the differential voltage corresponding to the second minimum point (p2) is smaller than the target differential voltage of the target peak (tp). Therefore, the reference point (rp) determined by the control unit (130) may be located between the target peak (tp) and the second minimum point (p2).

[0104] Accordingly, the control unit (130) can be configured to set the capacity section from the target peak (tp) to the reference point (rp) as the target capacity section (TR).

[0105] For example, in the embodiment of FIG. 5, the target differential voltage of the target peak (tp) is dV1. In the correction profile (CP), there are six points where the differential voltage is dV1, excluding the target peak (tp). The control unit (130) can determine the point closest to the target peak (tp) among the six points as the reference point (rp). In addition, the control unit (130) can set the capacity section from the capacity of the target peak (tp) to the capacity of the reference point (rp) as the target capacity section (TR).

[0106] If the differential voltage corresponding to the second minimum point (p2) is greater than the target differential voltage of the target peak (tp), the target capacity interval (TR) may be set too wide. Since the characteristic point is a point adjacent to the target peak (tp), an excessively wide target capacity interval (TR) cannot accurately determine whether the profile shape has changed.

[0107] According to one embodiment, the control unit (130) may be configured to set the differential voltage corresponding to the second minimum point (p2) as the target differential voltage if the differential voltage of the target peak (tp) is smaller than the differential voltage of the second minimum point (p2) having the second smallest corresponding capacity among the plurality of minimum points.

[0108] In addition, the control unit (130) may be configured to correspond to the target differential voltage of the second minimum point (p2) in the correction profile (CP) and determine the reference point (rp) closest to the second minimum point (p2).

[0109] According to one embodiment, the control unit (130) can determine a reference point (rp) between a first minimum point (p1) and a second minimum point (p2).

[0110] Finally, the control unit (130) can be configured to set the capacity section from the reference point (rp) to the second minimum point (p2) as the target capacity section (TR).

[0111] In one embodiment, the control unit (130) can set an appropriate target capacity range (TR) based on the capacity of the second minimum point (p2) and the reference point (rp). Accordingly, the battery condition can be diagnosed based on the capacity range to which the characteristic point belongs in the target capacity range (TR).

[0112] For example, unlike the embodiment of FIG. 5, if the differential voltage of the target peak (tp) is lower than the differential voltage of the second minimum point (p2), the target capacity section (TR) may be set too wide. In this case, since the feature points belonging to the target capacity section (TR) according to the embodiment of FIG. 5 may also change, the state of the battery may be diagnosed incorrectly. The battery diagnosis device (100) according to one embodiment of the present invention has an advantage in that the state of the battery can be accurately diagnosed by appropriately setting the target capacity section (TR) even in an exceptional situation where the differential voltage corresponding to the target peak (tp) is lower than the differential voltage of the second minimum point (p2).

[0113] The battery diagnosis device (100) according to the present invention can be applied to a BMS (Battery Management System). For example, the BMS according to the present invention can include the battery diagnosis device (100) described above. In this configuration, at least some of the components of the battery diagnosis device (100) can be implemented by supplementing or adding to the functions of the components included in a conventional BMS. For example, the profile acquisition unit (110), profile correction unit (120), control unit (130), and storage unit (140) of the battery diagnosis device (100) can be implemented as components of the BMS.

[0114] Additionally, the battery diagnostic device (100) according to the present invention may be provided in a battery pack. For example, the battery pack according to the present invention may include the battery diagnostic device (100) described above and one or more battery cells. Additionally, the battery pack may further include electrical components (relays, fuses, etc.) and a case.

[0115] FIG. 8 is a schematic drawing of a battery pack (10) according to another embodiment of the present invention.

[0116] 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).

[0117] The measuring unit (12) can be connected to a first sensing line (SL1), a second sensing line (SL2), and a third sensing line (SL3). For example, the measuring unit (12) can be connected to a positive terminal of the battery (11) through the first sensing line (SL1), and can be connected to a 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).

[0118] And, the measuring unit (12) can be connected to the current measuring unit (A) through the third sensing line (SL3). For example, the current measuring unit (A) can be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of the battery (11). The measuring unit (12) can measure the charging current of the battery (11) through the third sensing line (SL3) to calculate the charging amount. In addition, the measuring unit (12) can measure the discharging current of the battery (11) through the third sensing line (SL3) to calculate the discharging amount.

[0119] For example, the profile acquisition unit (110) can receive battery information about the voltage and current of the battery from the measurement unit (12). Then, the profile acquisition unit (110) can generate a battery profile (BP) and a differential profile (DP) based on the battery information.

[0120] As another example, the profile acquisition unit (110) can receive a battery profile (BP) from the measurement unit (12). Then, the profile acquisition unit (110) can generate a differential profile (DP) based on the battery profile (BP).

[0121] As another example, the profile acquisition unit (110) can receive a differential profile (DP) from the measurement unit (12).

[0122] An external device may be connected to the positive terminal (P+) and negative terminal (P-) of the battery pack (10). For example, the external device may be a charging device or a load. In addition, 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.

[0123] FIG. 9 is a schematic drawing of a vehicle (900) according to another embodiment of the present invention.

[0124] Referring to FIG. 9, a battery pack according to an embodiment of the present invention may be included in a vehicle (900), such as an electric vehicle (EV) or a hybrid vehicle (HV). Furthermore, the battery pack (910) may drive the vehicle (900) by supplying power to a motor through an inverter provided in the vehicle (900). Here, the battery pack (910) may include a battery diagnostic device (100). For example, the vehicle (900) may include a battery diagnostic device (100). In this case, the battery diagnostic device (100) may be an onboard device included in the vehicle (900).

[0125] FIG. 10 is a diagram schematically illustrating a battery management method according to another embodiment of the present invention.

[0126] Referring to FIG. 10, the battery management method may include a profile acquisition step (S100), a target determination step (S200), a correction profile generation step (S300), a target peak determination step (S400), and a battery diagnosis step (S500).

[0127] Each step of the battery diagnosis method can be performed by the battery diagnosis device (100).

[0128] The profile acquisition step (S100) is a step of acquiring a differential profile (DP) indicating a correspondence between the capacity of the battery and the differential voltage, and can be performed by the profile acquisition unit (110).

[0129] For example, the profile acquisition unit (110) can directly receive the differential profile (DP) of the battery from the outside. For example, the profile acquisition unit (110) can acquire the differential profile (DP) by receiving the differential profile (DP) through a wired and / or wireless connection to the outside.

[0130] As another example, the profile acquisition unit (110) can directly receive the battery profile (BP) of the battery from the outside. Then, the profile acquisition unit (110) can generate a differential profile (DP) based on the battery profile (BP). According to one embodiment, the profile acquisition unit (110) can be connected to the outside via wire and / or wirelessly to receive the battery profile (BP) and directly generate the differential profile (DP) from the received battery profile (BP), thereby acquiring the differential profile (DP).

[0131] As another example, the profile acquisition unit (110) may receive battery information regarding the voltage and capacity of the battery. Furthermore, the profile acquisition unit (110) may generate a battery profile (BP) based on the received battery information, and may generate a differential profile (DP) based on the generated battery profile (BP). The profile acquisition unit (110) may acquire the differential profile (DP) by directly generating the differential profile (DP) based on the battery information.

[0132] The target determination step (S200) is a step of determining a target C-rate corresponding to a differential profile (DP), and can be performed by the profile correction unit (120).

[0133] For example, the profile correction unit (120) can receive information about the differential profile (DP) and C-rate from the profile acquisition unit (110). Then, the profile correction unit (120) can determine the C-rate corresponding to the differential profile (DP) as the target C-rate.

[0134] The correction profile generation step (S300) is a step of generating a correction profile (CP) by correcting a differential profile (DP) based on an overvoltage profile corresponding to a target C-rate, and can be performed by a profile correction unit (120).

[0135] In addition, the profile correction unit (120) may be configured to select an overvoltage profile corresponding to the target C-rate from among a plurality of pre-stored overvoltage profiles. The profile correction unit (120) may be configured to generate a correction profile (CP) by calculating the difference between the differential profile (DP) and the overvoltage profile.

[0136] For example, the profile correction unit (120) can generate a correction profile (CP) by calculating the voltage-dependent differential capacity difference between the differential profile (DP) and the overvoltage profile.

[0137] The target peak determination step (S400) is a step of determining a minimum point with a minimum corresponding capacity among the minimum points included in the correction profile (CP) as a target peak (tp) and setting a target capacity section (TR) based on a target differential voltage corresponding to the target peak (tp), which can be performed by the control unit (130).

[0138] For example, the control unit (130) may be configured to determine a minimum point with the smallest corresponding capacity among a plurality of minimum points included in the correction profile (CP) as the target peak (tp). In the embodiment of FIG. 5, the correction profile (CP) may include a first minimum point (p1), a second minimum point (p2), a third minimum point (p3), and a fourth minimum point (p4). Since the capacity corresponding to the first minimum point (p1) is the smallest among the first to fourth minimum points (p4), the control unit (130) may determine the first minimum point (p1) as the target peak (tp). In addition, the control unit (130) may be configured to set a target capacity section (TR) based on a target differential voltage corresponding to the target peak (tp).

[0139] The battery diagnosis step (S500) is a step for diagnosing the state of the battery based on the modification of the target capacity section (TR) of the compensation profile (CP), and can be performed by the control unit (130).

[0140] The control unit (130) can diagnose the state of the battery based on whether the target capacity section (TR) has changed in shape. For example, the control unit (130) can determine whether the target capacity section (TR) has changed in shape and diagnose the state of the battery in response to the determination result.

[0141] For example, the control unit (130) can diagnose whether the battery has lost available lithium. For example, if the control unit (130) determines that the shape of the target capacity section (TR) has changed, the control unit can diagnose the battery's state as a state of available lithium loss.

[0142] The embodiments of the present invention described above are not implemented only through devices and methods, but may also be implemented through a program that realizes a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded, and such implementation can be easily implemented by an expert in the technical field to which the present invention belongs based on the description of the embodiments described above.

[0143] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0144] In addition, the present invention described above is not limited to the above-described embodiments and the attached drawings, and all or part of each embodiment may be selectively combined and configured so that various modifications can be made, as those skilled in the art can make various substitutions, modifications, and changes within the scope of the technical idea of ​​the present invention.

[0145] (Explanation of symbols)

[0146] 10: Battery pack

[0147] 11: Battery

[0148] 12: Measurement section

[0149] 100: Battery Diagnostic Device

[0150] 110: Profile acquisition section

[0151] 120: Profile correction section

[0152] 130: Control unit

[0153] 140: Storage

[0154] 900: Car

[0155] 910: Battery Pack

Claims

1. A profile acquisition unit configured to acquire a differential profile indicating a correspondence between the capacity of the battery and the differential voltage; A profile correction unit configured to determine a target C-rate (Current-rate) corresponding to the above differential profile and generate a correction profile by correcting the differential profile based on an overvoltage profile corresponding to the target C-rate; and A battery diagnostic device comprising a control unit configured to diagnose the state of the battery based on the shape of the target capacity section of the above correction profile.

2. In paragraph 1, The above control unit, A battery diagnostic device configured to determine a minimum point with a minimum corresponding capacity among a plurality of minimum points included in the above correction profile as a target peak, and to set the target capacity range based on a target differential voltage corresponding to the target peak.

3. In paragraph 2, The above control unit, A battery diagnostic device configured to determine a reference point closest to the target peak, corresponding to the target differential voltage in the above compensation profile, and to set the capacity section from the target peak to the reference point as the target capacity section (TR).

4. In paragraph 2, The above control unit, A battery diagnostic device configured to set the differential voltage corresponding to the second minimum point to the target differential voltage when the differential capacity of the target peak is smaller than the differential capacity of the second minimum point among the plurality of minimum points.

5. In paragraph 4, The above control unit, A battery diagnostic device configured to determine a reference point closest to the second minimum point corresponding to the target differential voltage in the above compensation profile, and to set a capacity range from the reference point to the second minimum point as the target capacity range.

6. In paragraph 1, The above control unit, A battery diagnostic device configured to divide the above target capacity section into a low capacity section and a high capacity section, and to diagnose the state of the battery based on the section to which the characteristic point with the largest corresponding differential voltage belongs in the above target capacity section.

7. In paragraph 6, The above control unit, A battery diagnostic device configured to diagnose the state of the battery as a state of available lithium loss when the above characteristic point falls within the high-capacity range.

8. In paragraph 1, The above profile correction part, A battery diagnostic device configured to generate the compensation profile by calculating the difference between the differential profile and the overvoltage profile.

9. In paragraph 1, The above overvoltage profile is configured to be stored in advance for each of a plurality of C-rates, The above profile correction part, A battery diagnostic device configured to select an overvoltage profile corresponding to the target C-rate from among multiple pre-stored overvoltage profiles.

10. In paragraph 1, The above overvoltage profile is, A battery diagnostic device preset based on a reference differential profile of a reference battery for a reference C-rate and a target differential profile of the reference battery for the target C-rate.

11. In paragraph 10, The above overvoltage profile is, A battery diagnostic device preset to indicate the difference between the above reference differential profile and the above target differential profile.

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

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

14. A profile acquisition step for acquiring a differential profile indicating the correspondence between the capacity of the battery and the differential voltage; A target determination step for determining a target C-rate corresponding to the above differential profile; A compensation profile generation step for generating a compensation profile by compensating the differential profile based on an overvoltage profile corresponding to the target C-rate; and A battery diagnosis method comprising a battery diagnosis step of diagnosing the state of the battery based on the modification of the target capacity section of the above correction profile.

15. A profile acquisition step for acquiring a differential profile indicating the correspondence between the capacity of the battery and the differential voltage; A target determination step for determining a target C-rate corresponding to the above differential profile; A compensation profile generation step for generating a compensation profile by compensating the differential profile based on an overvoltage profile corresponding to the target C-rate; and A non-transitory readable storage medium storing a program for executing a battery diagnosis method including a battery diagnosis step of diagnosing the state of the battery based on the modification of the target capacity section of the above correction profile.

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