Battery diagnostic equipment and methods

Abstract

The invention relates to a battery diagnostic device comprising: a characteristic curve acquisition unit which acquires the differential characteristic curve representing the correspondence between voltage and differential capacity of the battery; a characteristic curve correction unit which determines the target speed C corresponding to the differential characteristic curve, and corrects the differential characteristic curve based on the overvoltage characteristic curve corresponding to the target speed C, thereby generating a corrected characteristic curve; and a control unit which determines the first and second target peaks in the corrected characteristic curve, and diagnoses the state of the battery based on the behavior of the first and second target peaks.

Description

Battery diagnostic device and method

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0012286, 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] In one embodiment of the present invention, a battery diagnosis device and method for relatively quickly diagnosing the current state of a battery are provided.

[0007] Various 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 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 voltage and a differential capacity of a battery; a profile correction unit configured to determine a target C-rate (C-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 determine a first target peak and a second target peak from the correction profile and diagnose a state of the battery based on a behavior of the first target peak and a behavior of the second target peak.

[0009] The control unit may be configured to determine, as a first target peak, a minimum point among the minimum points included in the correction profile, the minimum voltage of which is in the middle or higher voltage range of the battery.

[0010] The above control unit may be configured to determine the maximum point with the largest corresponding voltage among the maximum points included in the correction profile as the second target peak.

[0011] The control unit may be configured to diagnose the state of the battery as a positive electrode capacity loss state when the voltage corresponding to the first target peak increases as the charge / discharge cycle of the battery progresses and the differential capacity corresponding to the second target peak decreases as the charge / discharge cycle of the battery progresses.

[0012] 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.

[0013] The above overvoltage profile can be configured to be pre-saved for each of a plurality of C-rates.

[0014] 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.

[0015] 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.

[0016] The above overvoltage profile can be preset to represent the difference between the reference differential profile and the target differential profile.

[0017] 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.

[0018] A vehicle according to another aspect of the present invention may include a battery diagnostic device according to one aspect of the present invention.

[0019] A battery diagnosis method according to another aspect of the present invention may include a profile acquisition step of acquiring a differential profile indicating a correspondence between a voltage and a differential capacity of a battery; a target 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; a target peak determination step of determining a first target peak and a second target peak in the correction profile; and a battery diagnosis step of diagnosing a state of the battery based on a behavior of the first target peak and a behavior of the second target peak.

[0020] According to another aspect of the present invention, a non-transitory readable storage medium may store 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 voltage and a differential capacity of a battery; 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; a target peak determination step of determining a first target peak and a second target peak in the correction profile; and a battery diagnosis step of diagnosing a state of the battery based on a behavior of the first target peak and a behavior of the second target peak.

[0021] 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.

[0022] In addition, according to one aspect of the present invention, since the state of the battery is diagnosed relatively quickly whether there is a loss of positive electrode capacity, a diagnosis result regarding the current state of the battery can be provided relatively quickly.

[0023] 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.

[0024] 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.

[0025] FIG. 1 is a schematic diagram illustrating a battery diagnostic device according to one embodiment of the present invention.

[0026] FIG. 2 is a diagram schematically illustrating a battery profile according to one embodiment of the present invention.

[0027] FIG. 3 is a schematic diagram illustrating a differential profile according to one embodiment of the present invention.

[0028] FIG. 4 is a diagram schematically illustrating a differential profile and a correction profile according to one embodiment of the present invention.

[0029] FIG. 5 is a drawing schematically illustrating a correction profile according to one embodiment of the present invention.

[0030] FIG. 6 is a diagram schematically illustrating a plurality of correction profiles according to one embodiment of the present invention.

[0031] FIG. 7 is a diagram schematically illustrating the state of a battery corresponding to a plurality of correction profiles according to one embodiment of the present invention.

[0032] FIG. 8 is a schematic drawing of a battery pack according to another embodiment of the present invention.

[0033] FIG. 9 is a schematic drawing of a vehicle according to another embodiment of the present invention.

[0034] FIG. 10 is a diagram schematically illustrating a battery diagnosis method according to another embodiment of the present invention.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] FIG. 1 is a schematic diagram illustrating a battery diagnostic device (100) according to one embodiment of the present invention.

[0042] 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).

[0043] 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.

[0044] The profile acquisition unit (110) can be configured to acquire a differential profile (DP) indicating a correspondence between the voltage and differential capacity of the battery.

[0045] For example, a battery profile (BP) is a profile that represents the relationship between the voltage (V) and the capacity (Q) when the battery's State of Charge (SOC) is a preset start SOC, or a preset end SOC from 0%, or when it is charged to 100%. As another example, a battery profile (BP) may represent the relationship between the voltage (V) and the capacity (Q) when the battery's SOC is a preset start SOC, or a preset end SOC from 100%, or when it is discharged to 0%.

[0046] 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).

[0047] And, when the battery profile (BP) is differentiated with respect to the voltage, a differential profile (DP) representing the correspondence between the differential capacity (dQ / dV) and the voltage (V) can be generated.

[0048] 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 voltage (V) and the Y-axis is set to differential capacitance (dQ / dV).

[0049] 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 C-rate, such as 0.05C.

[0050] 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).

[0051] 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 voltage. For example, the profile acquisition unit (110) may be connected to the outside via wires and / or wirelessly to receive a battery profile (BP), and directly generate a differential profile (DP) from the received battery profile (BP), thereby acquiring the differential profile (DP).

[0052] 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).

[0053] 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 (110) may transmit the acquired differential profile (DP) to the control unit (130).

[0054] According to one embodiment, the profile correction unit (120) may be configured to determine a target C-rate corresponding to a differential profile (DP).

[0055] 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).

[0056] 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.

[0057] 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.

[0058] 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 difference between the reference differential profile (DP) and the target differential profile (DP).

[0059] For example, assume that 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 is 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 is 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.

[0060] 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.

[0061] Overvoltage profiles can be configured to be pre-saved for each of multiple C-rates.

[0062] For example, multiple overvoltage profiles may be provided, and the C-rates corresponding to each of the multiple overvoltage profiles may be different from each other. For example, based on a unit C-rate, an overvoltage profile corresponding to each C-rate may be stored in advance.

[0063] 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.

[0064] 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.

[0065] 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).

[0066] 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.

[0067] 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.

[0068] In the embodiment of FIG. 4, the correction profile (CP) can be generated based on the voltage-dependent differential capacity difference between the differential profile (DP) and the corresponding overvoltage profile (not shown). For example, 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.

[0069] Referring to FIG. 5, the control unit (130) can be configured to determine a first target peak (tp1) and a second target peak (tp2) in the correction profile (CP).

[0070] The control unit (130) may be configured to determine the minimum point among the minimum points included in the correction profile (CP) whose corresponding voltage is the minimum in the middle or higher voltage range of the battery as the first target peak (tp1).

[0071] The control unit (130) may determine one or more local minimum points by considering the rate of change of the differential capacitance with respect to the voltage in the compensation profile (CP). For example, a local minimum point is a point where the rate of change of the differential capacitance with respect to the voltage is 0, and is a downward convex peak in the graph of the compensation profile (CP) of FIGS. 4 and 5. The compensation profile (CP) may include multiple local minimum points. In addition, the control unit (130) may determine, among the multiple local minimum points, a local minimum point with a minimum corresponding voltage in a voltage range above the middle as the first target peak (tp1).

[0072] For example, it is assumed that the voltage range of the battery is Vi[V] to Vf[V]. The mid-voltage of the battery can be calculated according to the formula of "(Vf-Vi) / 2". For example, the mid-voltage range of the battery is a voltage range greater than "(Vf-Vi) / 2" and less than Vf. The control unit (130) can determine the local minimum point corresponding to the minimum voltage greater than the mid-voltage of the battery ((Vf-Vi) / 2) as the first target peak (tp1).

[0073] In the embodiment of FIG. 5, the correction profile (CP) may include a first minimum point (p1), a second minimum point (p2), and a third minimum point (p3). Since the mid-voltage of the battery is approximately 3.6 [V], the voltage corresponding to the first minimum point (p1) is the largest voltage in the voltage range below the mid-voltage of the battery. The voltage corresponding to the second minimum point (p2) is the smallest voltage in the voltage range above the mid-voltage of the battery. The voltage corresponding to the third minimum point (p3) is the largest voltage in the voltage range above the mid-voltage of the battery. Therefore, the control unit (130) may determine the second minimum point (p2) as the first target peak (tp1).

[0074] The control unit (130) may be configured to determine the maximum point with the largest corresponding voltage among the maximum points included in the correction profile (CP) as the second target peak (tp2).

[0075] According to one embodiment, the control unit (130) may determine one or more local maxima by considering the rate of change of the differential capacitance with respect to the voltage in the compensation profile (CP). For example, a local maxima is a point where the rate of change of the differential capacitance with respect to the voltage is 0, which is a peak convex upward in the graph of the compensation profile (CP) of FIG. 5. The compensation profile (CP) may include multiple local maxima. In addition, the control unit (130) may determine the local maxima with the largest corresponding voltage among the multiple local maxima as the second target peak (tp2). In the embodiment of FIG. 5, the second target peak (tp2) may be included in a voltage range of 4.0 [V] or higher.

[0076] In the embodiment of FIG. 5, the correction profile (CP) includes four maximum points located at approximately 3.4 [V], approximately 3.65 [V], approximately 3.95 [V], and approximately 4.1 [V]. Since the voltage corresponding to the maximum point at approximately 4.1 [V] among the multiple maximum points is the largest, the control unit (130) can determine this maximum point as the second target peak (tp2).

[0077] The control unit (130) may be configured to diagnose the state of the battery based on the behavior of the first target peak (tp1) and the behavior of the second target peak (tp2).

[0078] For example, the control unit (130) can diagnose whether the battery has a positive electrode capacity loss based on the behavior of the first target peak (tp1) and the second target peak (tp2). For example, the control unit (130) can diagnose whether the battery is in a positive electrode capacity loss state. The positive electrode capacity loss state refers to a state in which the positive electrode of the battery is physically and / or chemically damaged, resulting in the loss of the positive electrode that can participate in charge and discharge. The positive electrode capacity loss state can indicate a deterioration pattern of a battery in which the positive electrode capacity has been lost.

[0079] First, the control unit (130) can determine the change behavior of the first target peak (tp1) according to the time series. For example, the first target peak (tp1) may be determined each time a charge / discharge cycle of the battery is performed, and the voltage and differential capacity corresponding to the first target peak (tp1) may be stored. The control unit (130) may determine the change behavior of the first target peak (tp1) by comparing the voltages and / or differential capacities of a plurality of stored first target peaks (tp1). For example, the control unit (130) may compare the voltages of the first target peaks (tp1) according to the time series and determine that the voltage of the first target peak (tp1) has decreased, remained constant, or increased. In addition, the control unit (130) may compare the differential capacities of the first target peaks (tp1) according to the time series and determine that the differential capacity of the first target peak (tp1) has decreased, remained constant, or increased.

[0080] In addition, the control unit (130) can determine the change behavior of the second target peak (tp2) according to the time series. For example, the second target peak (tp2) may be determined each time a charge / discharge cycle of the battery is performed, and the voltage and differential capacity corresponding to the second target peak (tp2) may be stored. The control unit (130) can determine the change behavior of the second target peak (tp2) by comparing the voltages and / or differential capacities of a plurality of stored second target peaks (tp2). For example, the control unit (130) can compare the voltages of the second target peaks (tp2) according to the time series and determine that the voltage of the second target peak (tp2) has decreased, remained constant, or increased. In addition, the control unit (130) can compare the differential capacities of the second target peaks (tp2) according to the time series and determine that the differential capacity of the second target peak (tp2) has decreased, remained constant, or increased.

[0081] The control unit (130) can determine whether the voltage corresponding to the first target peak (tp1) increases as the cycle progresses. In addition, the control unit (130) can determine whether the differential capacity corresponding to the second target peak (tp2) decreases as the cycle progresses. When the voltage of the first target peak (tp1) increases and the differential capacity of the second target peak (tp2) decreases as the cycle progresses, the control unit (130) can be configured to diagnose the state of the battery as a state of positive electrode capacity loss.

[0082] FIG. 6 is a diagram schematically illustrating a plurality of correction profiles (CP) according to one embodiment of the present invention.

[0083] The embodiment of FIG. 6 includes 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. The voltage of the first target peak (tp1) of the plurality of correction profiles (CP) increases as the cycle progresses. In addition, the differential capacity of the second target peak (tp2) of the plurality of correction profiles (CP) decreases as the cycle progresses. Therefore, the control unit (130) can diagnose the state of the battery as a state of positive electrode capacity loss.

[0084] FIG. 7 is a schematic diagram illustrating the state of a battery corresponding to multiple correction profiles (CPs) according to one embodiment of the present invention. The embodiments of FIG. 6 and FIG. 7 relate to the same battery. For example, multiple correction profiles (CPs) for a battery to be diagnosed are illustrated in FIG. 6, and the state of the battery to be diagnosed for each cycle is illustrated in FIG. 7.

[0085] In the embodiment of FIG. 7, the anode degradation rate is the rate of loss of anode capacity, meaning the rate at which the anode capacity has deteriorated compared to the initial level. For example, when 2% of the anode capacity is unusable compared to the initial level, the anode degradation rate is 2%.

[0086] The available lithium degradation rate is the rate at which lithium available for charge and discharge is lost, indicating the rate at which the available lithium has deteriorated compared to the initial capacity. For example, if 1% of the initial available lithium is unusable, the available lithium degradation rate is 1%.

[0087] The cathode degradation rate is the rate of loss of cathode capacity, indicating the rate at which the cathode capacity has deteriorated compared to its initial state. For example, if 1% of the initial cathode capacity is unusable, the cathode degradation rate is 1%.

[0088] The anode degradation rate, available lithium degradation rate, and anode degradation rate of the battery corresponding to the first cycle (ini) are 0.0%. The anode degradation rate of the battery corresponding to the 10th cycle is 0.7%, the available lithium degradation rate is 0.3%, and the anode degradation rate is 0.7%. The anode degradation rate of the battery corresponding to the 20th cycle is 1.0%, the available lithium degradation rate is 0.1%, and the anode degradation rate is 0.7%. The anode degradation rate of the battery corresponding to the 30th cycle is 1.5%, the available lithium degradation rate is 0.1%, and the anode degradation rate is 1.3%. The anode degradation rate of the battery corresponding to the 40th cycle is 1.9%, the available lithium degradation rate is 0.2%, and the anode degradation rate is 1.3%. The anode degradation rate of the battery corresponding to the 50th cycle is 2.1%, the available lithium degradation rate is 0.0%, and the anode degradation rate is 0.5%. The anode degradation rate of the battery corresponding to the 60th cycle is 2.5%, the available lithium degradation rate is 0.1%, and the anode degradation rate is 1.4%. The anode degradation rate of the battery corresponding to the 70th cycle is 2.8%, the available lithium degradation rate is 0.0%, and the anode degradation rate is 0.3%. The anode degradation rate of the battery corresponding to the 80th cycle is 3.1%, the available lithium degradation rate is 0.0%, and the anode degradation rate is 1.3%. The anode degradation rate of the battery corresponding to the 90th cycle is 3.5%, the available lithium degradation rate is 0.2%, and the anode degradation rate is 0.5%.

[0089] Referring to Fig. 7, as the charge / discharge cycle of the battery progresses, the anode degradation rate of the battery gradually increases, but the available lithium degradation rate and the anode degradation rate do not show an increasing trend. For example, the anode capacity of the battery is lost, but the available lithium and anode capacities are not lost. Meanwhile, referring to Fig. 6, as the cycle progresses, the voltage of the first target peak (tp1) gradually increases, and the differential capacity of the second target peak (tp2) gradually decreases. Therefore, the control unit (130) can diagnose whether the anode capacity of the battery is lost based on the behavior of the first target peak (tp1) and the second target peak (tp2).

[0090] 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.

[0091] 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 (Electronically 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).

[0092] The storage unit (140) can store a battery profile (BP), a differential profile (DP), and a correction profile (CP).

[0093] 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.

[0094] 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.

[0095] FIG. 8 is a schematic drawing of a battery pack (10) according to another embodiment of the present invention.

[0096] 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).

[0097] The measuring unit (12) can be connected to a first sensing line (SL1), a second sensing line (SL2), and a third sensing line (SL3). 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).

[0098] 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.

[0099] 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.

[0100] 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).

[0101] As another example, the profile acquisition unit (110) can receive a differential profile (DP) from the measurement unit (12).

[0102] An external device can be connected to the positive terminal (P+) and negative terminal (P-) of the battery pack (10). For example, the external device can 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) can be electrically connected.

[0103] FIG. 9 is a schematic drawing of a vehicle (900) according to another embodiment of the present invention.

[0104] 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).

[0105] FIG. 10 is a diagram schematically illustrating a battery management method according to another embodiment of the present invention.

[0106] Referring to FIG. 10, the battery management method may include a profile acquisition step (S100), a target determination step (S200), a correction profile (CP) generation step (S300), a target peak determination step (S400), and a battery diagnosis step (S500).

[0107] Each step of the battery diagnosis method can be performed by the battery diagnosis device (100).

[0108] 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).

[0109] 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.

[0110] 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 received battery profile (BP). 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).

[0111] 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 directly generate the differential profile (DP) based on the received battery information, thereby acquiring the differential profile (DP).

[0112] 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).

[0113] 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.

[0114] The correction profile (CP) 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).

[0115] 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.

[0116] 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.

[0117] The target peak determination step (S400) is a step of determining a first target peak (tp1) and a second target peak (tp2) in a correction profile (CP), and can be performed by the control unit (130).

[0118] For example, the control unit (130) may be configured to determine, among the local minimum points included in the correction profile (CP), the local minimum point whose corresponding voltage is the minimum in the mid-range or higher voltage range of the battery as the first target peak (tp1). In addition, the control unit (130) may be configured to determine, among the local maximum points included in the correction profile (CP), the local maximum point whose corresponding voltage is the largest as the second target peak (tp2).

[0119] The battery diagnosis step (S500) is a step for diagnosing the state of the battery based on the behavior of the first target peak (tp1) and the behavior of the second target peak (tp2), and can be performed by the control unit (130).

[0120] For example, the control unit (130) can determine whether the voltage corresponding to the first target peak (tp1) increases as the cycle progresses. In addition, the control unit (130) can determine whether the differential capacity corresponding to the second target peak (tp2) decreases as the charge / discharge cycle of the battery progresses. When the voltage of the first target peak (tp1) increases and the differential capacity of the second target peak (tp2) decreases as the charge / discharge cycle of the battery progresses, the control unit (130) can be configured to diagnose the state of the battery as a state of positive electrode capacity loss.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] (Explanation of symbols)

[0125] 10: Battery pack

[0126] 11: Battery

[0127] 12: Measurement section

[0128] 100: Battery Diagnostic Device

[0129] 110: Profile acquisition section

[0130] 120: Profile correction section

[0131] 130: Control unit

[0132] 140: Storage

[0133] 900: Car

[0134] 910: Battery Pack

Claims

1. A profile acquisition unit configured to acquire a differential profile indicating a correspondence between the voltage and differential capacity of a battery; 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 diagnosis device comprising a control unit configured to determine a first target peak and a second target peak in the above correction profile and diagnose a state of the battery based on a behavior of the first target peak and a behavior of the second target peak.

2. In paragraph 1, The above control unit, A battery diagnostic device configured to determine, as a first target peak, a minimum point among the minimum points included in the above correction profile, the minimum voltage in the middle or higher voltage range of the battery.

3. In paragraph 1, The above control unit, A battery diagnostic device configured to determine the maximum point with the largest corresponding voltage among the maximum points included in the above correction profile as the second target peak.

4. In paragraph 1, The above control unit, A battery diagnostic device configured to diagnose the state of the battery as a positive electrode capacity loss state when the voltage corresponding to the first target peak increases as the charge / discharge cycle of the battery progresses and the differential capacity corresponding to the second target peak decreases as the charge / discharge cycle of the battery progresses.

5. 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.

6. 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 a plurality of pre-stored overvoltage profiles.

7. 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.

8. In paragraph 7, 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.

9. A battery pack comprising a battery diagnostic device according to any one of claims 1 to 8.

10. A vehicle including a battery diagnostic device according to any one of claims 1 to 8.

11. A profile acquisition step for acquiring a differential profile representing the correspondence between the voltage and differential capacity of the battery; 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; A target peak determination step for determining a first target peak and a second target peak in the above correction profile; and A battery diagnosis method comprising a battery diagnosis step of diagnosing the state of the battery based on the behavior of the first target peak and the behavior of the second target peak.

12. A profile acquisition step for acquiring a differential profile representing the correspondence between the voltage and differential capacity of the battery; 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; A target peak determination step for determining a first target peak and a second target peak in the above correction profile; and A non-transitory readable storage medium storing a program for executing a battery diagnosis method, the method including a battery diagnosis step of diagnosing the state of the battery based on the behavior of the first target peak and the behavior of the second target peak.

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