Battery diagnostic device, battery pack, electric vehicle, and battery diagnostic method

Abstract

A battery diagnostic device, a battery pack, an electric vehicle, and a battery diagnostic method are provided. The battery diagnostic device according to the present invention is provided for a battery array including a first battery to an mth battery (m is a natural number equal to or greater than 3) connected in series. The battery diagnostic device includes a sensing unit that detects the voltage of each of the first battery to the mth battery, and a control unit that generates a first voltage profile to an mth voltage profile that indicate a voltage change history of each of the first battery to the mth battery during charging or discharging of the battery array. The control unit diagnoses the battery array by comparing a reference voltage profile, which is any one of the first voltage profile to the mth voltage profile, with a first comparison voltage profile to an (m-1)th comparison voltage profile that are the remaining (m-1) voltage profiles other than the reference voltage profile.

Description

Technical Field

[0001] The present invention relates to battery diagnosis, and more particularly, to a technique for diagnosing abnormalities in a plurality of batteries connected in series.

[0002] This application claims priority based on Korean Patent Application No. 10-2022-0111696 filed on September 2, 2022, and Korean Patent Application No. 10-2023-0103523 filed on August 8, 2023, and all the contents disclosed in the specifications and drawings of the applications are incorporated into this application.

Background Art

[0003] In recent years, the demand for portable electronic products such as notebook computers, video cameras, and mobile phones has rapidly increased, and as the development of electric vehicles, energy storage batteries, robots, artificial satellites, etc. has become full-scale, research on high-performance batteries that can be repeatedly charged and discharged has been actively conducted.

[0004] Examples of currently commercialized batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium batteries, etc. Among them, lithium batteries are in the spotlight because they have almost no memory effect compared to nickel-based batteries, so they can be freely charged and discharged, have a very low self-discharge rate, and have a high energy density.

[0005] Although various studies are being conducted on such batteries in terms of high capacity and high density, the aspects of improving lifespan and safety are also important. For this purpose, it is necessary to suppress the decomposition reaction with the electrolyte on the surface of the electrode, and prevention of overcharging and over-discharging is required.

[0006] In particular, during charging or discharging of a battery array containing multiple batteries connected in series, the same current flows through all batteries, making it difficult to diagnose the condition of individual batteries. Therefore, there is a need to develop techniques to diagnose individual battery abnormalities by analyzing the voltage behavior of each of the multiple batteries during charging or discharging. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Korean Patent Application Publication No. 10-2018-0092863 [Overview of the project] [Problems that the invention aims to solve]

[0008] This invention was devised to solve the above-mentioned problems, and aims to provide a battery diagnostic device and battery diagnostic method that can quickly and accurately detect abnormalities in individual batteries through a relative comparison of multiple voltage profiles obtained for multiple batteries.

[0009] Other objects and advantages of the present invention can be understood from the following description and will be more clearly evident from the embodiments of the present invention. Furthermore, the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0010] A battery diagnostic device according to one aspect of the present invention is provided for a battery array including a first battery to the mth battery (where m is a natural number of 3 or more) connected in series. The battery diagnostic device includes a sensing unit configured to detect the voltage of each of the first to mth batteries, and a control unit configured to generate first to mth voltage profiles showing the voltage change history of each of the first to mth batteries based on voltage measurement data collected from the sensing unit during charging or discharging of the battery array. The control unit is configured to diagnose the battery array by comparing a reference voltage profile, which is one of the first to mth voltage profiles, with a first to (m-1) comparison voltage profile, which are the remaining (m-1) voltage profiles other than the reference voltage profile.

[0011] The control unit may be configured to adjust the first comparison voltage profile to the (m-1) comparison voltage profile, respectively, so as to minimize the error with the reference voltage profile, in order to generate the first adjusted comparison voltage profile to the (m-1) adjusted comparison voltage profile. The control unit may be configured to generate first main adjustment information to the (m-1) main adjustment information indicating the adjustment level from the first comparison voltage profile to the (m-1) comparison voltage profile to the first adjusted comparison voltage profile to the (m-1) adjusted comparison voltage profile, and to diagnose the battery array based on the first main adjustment information to the (m-1) main adjustment information.

[0012] The control unit may be configured to determine the sum of squares or mean square error of the difference between the voltage of the j-th adjusted comparison voltage profile (where j is a natural number less than m) among the first adjusted comparison voltage profile to the (m-1)-th adjusted comparison voltage profile and the voltage of the reference voltage profile as the amount of error between the j-th comparison voltage profile and the reference voltage profile.

[0013] The control unit may be configured to determine the jth voltage shift factor from the j-comparison voltage profile to the j-adjusted comparison voltage profile. The jth main adjustment information among the first main adjustment information to the (m-1)th main adjustment information includes the jth voltage shift factor.

[0014] The control unit may be configured to diagnose abnormalities in each of the first batteries to the m-th batteries or the battery array based on the distribution of the first voltage shift factors to the (m-1) voltage shift factors of the first main adjustment information to the (m-1) main adjustment information.

[0015] The control unit may be configured to determine the jth voltage scale factor from the j-comparison voltage profile to the j-adjusted comparison voltage profile. The jth main adjustment information among the first main adjustment information to the (m-1)th main adjustment information may include the jth voltage scale factor.

[0016] The control unit may be configured to diagnose abnormalities in each of the first batteries to the m-th batteries or the battery array based on the distribution of the first voltage scale factors to the (m-1) voltage scale factors of the first main adjustment information to the (m-1) main adjustment information.

[0017] The control unit may be configured to generate a reference differential voltage profile from the reference voltage profile. The control unit may be configured to generate a first comparative differential voltage profile from the first comparative voltage profile to the (m-1) comparative voltage profile. The control unit may be configured to adjust the first comparative differential voltage profile to the (m-1) comparative differential voltage profile, respectively, so that the amount of error with the reference differential voltage profile is minimized, in order to generate a first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile. The control unit may be configured to generate first sub-adjustment information to the (m-1) sub-adjustment information indicating the level of adjustment from the first comparative differential voltage profile to the (m-1) comparative differential voltage profile to the first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile, and to diagnose abnormalities in each of the first batteries to the m-th battery or the battery array based on the first sub-adjustment information to the (m-1) sub-adjustment information.

[0018] The control unit may be configured to determine the j-th differential voltage shift factor from the j-compared differential voltage profile to the j-adjusted comparative differential voltage profile. The j-th sub-adjustment information among the first sub-adjustment information to the (m-1)-th sub-adjustment information may include the j-th differential voltage shift factor.

[0019] The control unit may be configured to determine the j-th differential voltage scale factor from the j-th comparative differential voltage profile to the j-th adjusted comparative differential voltage profile. The j-th sub-adjustment information among the first to (m-1)-th sub-adjustment information may include the j-th differential voltage scale factor.

[0020] A battery pack according to another aspect of the present invention includes the battery diagnostic device.

[0021] An electric vehicle according to yet another aspect of the present invention includes the battery pack.

[0022] A battery diagnostic method according to yet another aspect of the present invention is provided for a battery array including a first battery to the mth battery (where m is a natural number of 3 or more) connected in series. The battery diagnostic method includes the steps of: collecting voltage measurement data indicating the voltages of each of the first to mth batteries during charging or discharging of the battery array; generating first voltage profiles to the mth voltage profiles indicating the voltage change history of each of the first to mth batteries based on the voltage measurement data; and diagnosing the battery array by comparing a reference voltage profile, which is one of the first to mth voltage profiles, with a first comparison voltage profile to the (m-1)th comparison voltage profile, which are the remaining (m-1) voltage profiles other than the reference voltage profile.

[0023] The steps for diagnosing the battery array may include: adjusting the first comparison voltage profile to the (m-1)th comparison voltage profile so that the amount of error with the reference voltage profile is minimized, thereby generating the first adjusted comparison voltage profile to the (m-1)th adjusted comparison voltage profile; generating first main adjustment information to the (m-1)th main adjustment information indicating the adjustment level from the first comparison voltage profile to the (m-1)th comparison voltage profile to the first adjusted comparison voltage profile to the (m-1)th adjusted comparison voltage profile; and diagnosing abnormalities in each of the first batteries to the mth batteries or the battery array based on the first main adjustment information to the (m-1)th main adjustment information.

[0024] The battery diagnosis method may further include: generating a reference differential voltage profile from the reference voltage profile; generating first to (m - 1) comparison differential voltage profiles from the first to (m - 1) comparison voltage profiles; adjusting each of the first to (m - 1) comparison differential voltage profiles so that the error amount from the reference differential voltage profile is minimized, to generate first to (m - 1) adjusted comparison differential voltage profiles; and generating first to (m - 1) sub - adjustment information indicating the adjustment levels from the first to (m - 1) comparison differential voltage profiles to the first to (m - 1) adjusted comparison differential voltage profiles.

[0025] The step of diagnosing the battery array may diagnose the battery array further based on the first to (m - 1) sub - adjustment information.

Advantages of the Invention

[0026] According to one aspect of the present invention, by analyzing the adjustment information of an adjustment process for adjusting each of the remaining voltage profiles so that the error amount between one voltage profile among a plurality of voltage profiles associated one - to - one with a plurality of batteries connected in series and the one voltage profile is minimized, an abnormality of each battery can be detected. That is, since the change history of the voltage of each of the plurality of batteries can be analyzed to detect an abnormality, the speed of abnormality detection is improved compared to other diagnostic methods that require additional parameters such as battery temperature.

[0027] Also, according to one aspect of the present invention, by diagnosing individual battery abnormalities by calculating the error amount between each of the remaining voltage profiles and one voltage profile among the plurality of voltage profiles as a reference, it is possible to detect abnormalities without previously securing reference data for abnormality detection, and there is an advantage that a large - capacity memory is not essential.

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

[0029] The following drawings accompanying this specification illustrate preferred embodiments of the invention and, together with the detailed description of the invention, serve to further illustrate the technical idea of ​​the invention; therefore, the invention should not be construed as being limited solely to what is shown in the drawings. [Brief explanation of the drawing]

[0030] [Figure 1] This figure schematically shows a battery diagnostic device according to one embodiment of the present invention. [Figure 2] This diagram schematically shows the coupling relationship between the battery and the measurement unit shown in Figure 1. [Figure 3] This graph is referenced in the description of the adjustment actions that can be performed to generate an adjusted comparison voltage profile from the comparison voltage profile. [Figure 4] This graph is referenced in the description of the adjustment actions that can be performed to generate an adjusted comparison voltage profile from the comparison voltage profile. [Figure 5] This graph is referenced in the description of the adjustment actions that can be performed to generate an adjusted comparison voltage profile from the comparison voltage profile. [Figure 6] This graph is referenced in the description of the adjustment actions that can be performed to generate an adjusted comparison voltage profile from the comparison voltage profile. [Figure 7] This graph is referenced in the description of the adjustment actions that can be performed to generate an adjusted comparison voltage profile from the comparison voltage profile. [Figure 8] This is a diagram referenced in the explanation of the process for calculating the error between the reference voltage profile and the adjusted comparison voltage profile. [Figure 9] This figure is referenced in the explanation of the differential voltage profile generated from the voltage profile. [Figure 10] This figure is referenced in the explanation of the differential capacitance profile generated from the voltage profile. [Figure 11] This figure shows an example of the distribution of voltage scale factors related to specific adjustment operations in the adjustment process. [Figure 12] This figure shows another example of the distribution of voltage scale factors related to specific adjustment operations in the adjustment process. [Figure 13] This figure shows yet another example of the distribution of voltage scale factors related to specific adjustment operations in the adjustment process. [Figure 14] This figure shows yet another example of the distribution of voltage scale factors related to specific adjustment operations in the adjustment process. [Figure 15] This figure illustrates a battery pack according to one embodiment of the present invention. [Figure 16] Figure 15 is an illustrative diagram showing an electric vehicle including the battery pack shown. [Figure 17] This is a flowchart illustrating a battery diagnostic method according to one embodiment of the present invention. [Figure 18] Figure 17 is a flowchart illustrating the subroutines that may be included in step S1740. [Figure 19] This flowchart shows an example of a subroutine that may be added to step S1740 in Figure 17. [Figure 20] This flowchart shows another example of a subroutine that may be added to step S1740 in Figure 17. [Modes for carrying out the invention]

[0031] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary and dictionary meanings, but rather in a manner corresponding to the technical idea of ​​the present invention, in accordance with the principle that the inventor himself can appropriately define the concepts of terms in order to best describe the invention.

[0032] Therefore, the embodiments described herein and the configurations shown in the drawings represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the present invention. It should be understood that there are various equivalents and modifications that can be substituted for these at the time of this application.

[0033] Terms that include ordinal numbers, such as "1st," "2nd," etc., are used to distinguish one of several components from others, and these terms do not limit the components themselves.

[0034] Throughout the specification, when a part of it "includes" a component, this does not exclude other components unless otherwise specified, but rather means that it may include other components. Furthermore, terms such as "[control unit]" in the specification mean a unit that processes at least one function or operation, and can be embodied in hardware, software, or a combination of hardware and software.

[0035] Furthermore, when a part of the specification is described as being "connected" to another part, this includes not only "direct connections" but also "indirect connections" mediated by other elements.

[0036] Figure 1 is a schematic diagram of a battery diagnostic device according to one embodiment of the present invention, and Figure 2 is a schematic diagram showing the coupling relationship between the battery and the measurement unit shown in Figure 1.

[0037] Referring to Figures 1 and 2, the battery diagnostic device 100 includes a measurement unit 110 and a control unit 120, and may optionally further include a memory 130.

[0038] The battery diagnostic device 100 is provided to detect abnormalities in the battery array 20 or in each of the first batteries B1 to the mth battery Bm contained therein, where m is a natural number greater than or equal to 3.

[0039] The first battery B1 to the mth battery Bm are electrically connected in series within the battery array 20. The battery array 20 may be included in a battery pack (reference numeral 10 in Figure 15). In the following description common to the first battery B1 to the mth battery Bm, the numeral B will be used to indicate a battery (cell group).

[0040] Battery B may include at least one battery cell. A battery cell is defined as an energy storage element equipped with a negative terminal and a positive terminal, which can be repeatedly charged and discharged on its own. For example, a battery cell may be a lithium-ion cell or a lithium polymer cell. If Battery B includes multiple battery cells, Battery B may be referred to as a "cell group". At least two of the battery cells in cell group B may be connected in parallel.

[0041] The measurement unit 110 may be configured to measure the voltage of each of the first battery B1 to the mth battery Bm. Voltage measurements by the measurement unit 110 may be performed periodically at a predetermined sampling rate (e.g., 60 times / second). The measurement unit 110 may provide the control unit 120 with voltage measurement data, including the measured voltages of each of the first battery B1 to the mth battery Bm.

[0042] The measurement unit 110 may include a first voltage sensor to the mth voltage sensor. If i is a natural number less than or equal to m, the ith voltage sensor can generate a sensing signal indicating the voltage value across the ith battery Bi. The control unit 120 can collect the sensing signal (voltage measurement data) from the ith voltage sensor and monitor the voltage of the ith battery Bi in real time.

[0043] The measurement unit 110 may include a current sensor (reference numeral CS in Figure 15). The current sensor CS may include, for example, a known current sensing element such as a shunt resistor and / or a Hall sensor. The current sensor CS may generate a sensing signal (current measurement data) indicating the current value (i.e., the magnitude and direction of the current) of the current flowing through the battery array 20. The control unit 120 may periodically collect current measurement data from the current sensor CS and calculate the cumulative capacity (integrated current value) from a specific point in time based on this data.

[0044] The measuring unit 110 may include at least one temperature sensor TS. If the measuring unit 110 includes only one temperature sensor TS, the temperature measured by the temperature sensor TS may be treated as a representative temperature (e.g., average temperature) of the first battery B1 to the mth battery Bm.

[0045] Alternatively, the measurement unit 110 may include m temperature sensors TS, in which case the m temperature sensors TS may be configured to measure the temperature of each of the first battery B1 to the mth battery Bm. The control unit 120 can collect sensing signals from each of the m temperature sensors TS to monitor the temperature of each of the first battery B1 to the mth battery Bm in real time.

[0046] As the temperature sensor TS, a temperature detection method known in this industry, such as a thermocouple, can be used.

[0047] Referring to Figure 2, the first voltage sensor VS1 to the mth voltage sensor VSm are connected in parallel to the first battery B1 to the mth battery Bm in a one-to-one correspondence. That is, the pair of measurement terminals of the ith voltage sensor VSi are connected to the positive and negative terminals of the ith battery Bi, respectively.

[0048] Specifically, the first voltage sensor VS1 may be configured to measure the voltage across the terminals of the first battery B1 during charging or discharging. The second voltage sensor VS2 may be configured to measure the voltage across the terminals of the second battery B2 during charging or discharging. The mth voltage sensor VSm may be configured to measure the voltage during charging or discharging of the mth battery Bm.

[0049] Here, since the first battery B1 to the mth battery Bm are electrically connected in series with each other, an equal charging current or discharging current flows through the first battery B1 to the mth battery Bm during charging or discharging. For example, under the control of the control unit 120, the first battery B1 to the mth battery Bm can be charged or discharged with a constant current at a predetermined current rate.

[0050] The control unit 120 can generate first to mth voltage profiles, which show the voltage change history of each of the first battery B1 to the mth battery Bm, during charging or discharging of the battery pack 10. Each voltage profile is a type of voltage time series that shows the voltage change according to time or capacity, and can be said to be a relationship curve between time and voltage or a relationship curve between capacity and voltage. For the sake of explanation, it will be assumed below that each voltage profile shows the voltage change according to capacity.

[0051] As described above, during charging or discharging of the battery pack 10, an equal current flows through the first battery B1 to the mth battery Bm. Therefore, the control unit 120 can monitor the capacity change during charging or discharging of the battery pack 10 through ampere counting, which periodically integrates the current values ​​collected from the current sensor CS.

[0052] The control unit 120 can generate an i-th voltage profile based on the capacity and voltage of the i-th battery Bi while the first battery B1 to the m-th battery Bm are being charged or discharged by a constant or non-constant current. That is, the control unit 120 can generate the i-th voltage profile by repeatedly mapping the monitored capacity (or measurement time) and voltage of the i-th battery Bi to each other at each timing and recording it in memory. This generates a first voltage profile to the m-th voltage profile that are one-to-one associated with the first battery B1 to the m-th battery Bm. The battery diagnostic process that utilizes the voltage profile will be described in more detail below.

[0053] Memory 130 can store data and programs necessary for each component of the battery diagnostic device 100 to operate and function. Memory 130 can also store data collected and generated during the operation and functioning of the measurement unit 110 and the control unit 120. Memory 130 may be located inside or outside the control unit 120 and can be operably coupled to the control unit 120 by various well-known means such as a data bus. Memory 130 can store at least one program, application, data, or instruction executed by the control unit 120.

[0054] The memory 130 is not particularly limited in type, as long as it is a known information recording means capable of recording, erasing, updating, and reading data. The memory can be embodied in at least one of the following forms: flash® memory, hard disk, SSD (Solid State Disk), SDD (Solid Disk Drive), multimedia microcard, RAM (Random Access Memory), SRAM (Static RAM), ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable ROM), and PROM (Programmable ROM), but the present invention is not limited to such specific forms of memory. The memory 130 can also store program code that defines processes that can be executed by the control unit 120.

[0055] Memory 130 may store battery identification numbers that have been pre-assigned to the first battery B1 to the mth battery Bm. During the execution of the diagnostic process according to the present invention, the control unit 120 may map the identification number of the ith battery Bi to the data related to the ith battery Bi and record it in memory 130.

[0056] The control unit 120 may be configured to set one of the first to mth voltage profiles as the reference voltage profile, and the remaining (m-1) voltage profiles as the first to (m-1)th comparison voltage profiles.

[0057] The reference voltage profile may be randomly selected from the first to the mth voltage profiles. Alternatively, the control unit 120 may select as the reference voltage profile the voltage profile associated with one of the first to the mth batteries whose voltage or SOC is closest to the average of the first to the mth batteries.

[0058] The reference voltage profile may be a voltage profile set as a reference for relative comparison with the full charge capacity (FCC) of the first battery B1 to the mth battery Bm. The control unit 120 may also select the remaining (m-1) voltage profiles from the first to the mth voltage profiles, excluding the reference voltage profile, as the first to the (m-1)th comparison voltage profiles, which will be subject to the adjustment operation described later.

[0059] For example, if the voltage profile of the first battery B1 is selected as the reference voltage profile, the control unit 120 may set the second voltage profile to the mth voltage profile of the second battery B2 to the mth battery Bm to the first comparison voltage profile to the (m-1)th comparison voltage profile. Here, it is easily understood by those skilled in the art that the second voltage profile is set to the first comparison voltage profile and the mth voltage profile is set to the (m-1)th comparison voltage profile.

[0060] The control unit 120 compares the first to (m-1) comparison voltage profiles with the reference voltage profile to diagnose any abnormalities in the battery array 20 or battery B.

[0061] More specifically, the control unit 120 can adjust the first to (m-1) comparison voltage profiles to correspond to the reference voltage profile, thereby generating the first adjusted comparison voltage profile to the (m-1) adjusted comparison voltage profile. Corresponding to the reference voltage profile means that the amount of error with the reference voltage profile is minimized or within a predetermined tolerance range. Here, if j is a natural number less than m, the amount of error between the reference voltage profile and the j-th adjusted comparison voltage profile may be the sum of squares, root mean square error (RMSE), or integral value of the difference between the voltage of the j-th adjusted comparison voltage profile and the voltage of the reference voltage profile over a specific capacitance range, or the integral value of the absolute value of the voltage difference.

[0062] The j-th adjusted comparison voltage profile is one of several adjusted comparison voltage profiles obtained by adjusting the j-th comparison voltage profile to several levels. The control unit 120 calculates the root mean square error (RMSE) between each of the multiple adjusted comparison voltage profiles obtained from the j-th comparison voltage profile and the reference voltage profile, and can identify the one among the multiple adjusted comparison voltage profiles that has the smallest RMSE as the j-th adjusted comparison voltage profile. The adjustment operations that the control unit 120 performs on each comparison voltage profile to correspond to the reference voltage profile will be described in more detail later with reference to Figures 3 to 7.

[0063] The control unit 120 can generate first main adjustment information to (m-1) main adjustment information indicating the adjustment level from the first comparison voltage profile to the (m-1) comparison voltage profile to the first adjusted comparison voltage profile to the (m-1) adjusted comparison voltage profile. The j-th main adjustment information may be a dataset that defines how and to what extent the j-th comparison voltage profile was adjusted to generate the j-th adjusted comparison voltage profile.

[0064] The adjustment process from the first comparison voltage profile to the (m-1)th comparison voltage profile to the first adjusted comparison voltage profile to the (m-1)th adjusted comparison voltage profile requires a first adjustment operation (Y-axis shift) and may optionally further include at least one of the second adjustment operation (Y-axis scale), third adjustment operation (X-axis shift), and fourth adjustment operation (X-axis scale).

[0065] The first adjustment operation (Y-axis shift) may be an operation that moves the j-th comparison voltage profile along the Y-axis (voltage) as a whole. The amount of adjustment by the first adjustment operation may be called the voltage shift amount (or voltage shift factor). For example, a voltage shift factor of +0.1V means that the j-th adjusted comparison voltage profile is generally located about 0.1V higher (higher voltage) than the j-th comparison voltage profile.

[0066] The second adjustment operation (Y-axis scale) may be an operation that reduces or expands the j-th comparison voltage profile along the Y-axis. The amount of adjustment by the second adjustment operation may be called the voltage scale amount (or voltage scale factor). For example, a voltage scale factor of 101% means that the voltage range of the j-th adjusted comparison voltage profile is 1.01 times the voltage range of the j-th comparison voltage profile, and a voltage shift factor of 98% means that the voltage range of the j-th adjusted comparison voltage profile is 0.98 times the voltage range of the j-th comparison voltage profile.

[0067] The third adjustment operation (X-axis shift) may be an operation that shifts the j-th comparison voltage profile overall along the X-axis (capacitance). The amount of adjustment by the third adjustment operation may be called the capacitance shift amount (or capacitance shift factor). For example, a capacitance shift factor of -2.2Ah means that the j-th adjusted comparison voltage profile is generally located about 2.2Ah to the left (lower capacitance) than the j-th comparison voltage profile.

[0068] The fourth adjustment operation (X-axis scale) may be an operation that reduces or expands the j-th comparison voltage profile along the X-axis. The amount of adjustment by the fourth adjustment operation may be called the capacitance scale amount (or capacitance scale factor). For example, a capacitance scale factor of 103% means that the capacitance range of the j-th adjusted comparison voltage profile is 1.03 times the capacitance range of the j-th comparison voltage profile.

[0069] The j-th main adjustment information includes the adjustment amount from the first adjustment operation and may further include at least one of the adjustment amounts from the second to fourth adjustment operations. Furthermore, since no adjustment operation is performed on the reference voltage profile, the adjustment amounts for the first to fourth adjustment operations related to the reference voltage profile can be defaulted to 0V, 100%, 0Ah, and 100%, respectively. For reference, other units besides V, Ah, and % may be used as units for the adjustment amounts.

[0070] The control unit 120 may be configured to identify abnormalities in each of the first battery B1 to the mth battery Bm or in the battery array 20 based on the first main adjustment information to the (m-1)th main adjustment information.

[0071] The control unit 120 can identify that if the X-axis length (i.e., capacity range) of the j-th adjusted comparison voltage profile is relatively longer than the X-axis length of the j-th comparison voltage profile (e.g., expansion, capacity scale factor greater than 100%), the full charge capacity of the battery associated with the j-th comparison voltage profile is smaller than the full charge capacity of the reference battery by an amount corresponding to the adjustment information.

[0072] The control unit 120 can identify that if the X-axis length (i.e., capacity range) of the j-th adjusted comparison voltage profile is relatively shorter than the X-axis length of the j-th comparison voltage profile (e.g., reduced, capacity scale factor is less than 100%), the full charge capacity of the battery associated with the j-th comparison voltage profile is larger than the full charge capacity of the reference battery by an amount corresponding to the adjustment information.

[0073] For example, if the full charge capacity of the reference battery is 100Ah, the control unit 120 may determine that the full charge capacity of the battery associated with the j-th comparison voltage profile is 3%p less than the full charge capacity of the reference battery if the j-th main adjustment information is 103%.

[0074] The control unit 120 can analyze the distribution of adjustment amounts of the same type in the first main adjustment information to the (m-1) main adjustment information and diagnose abnormalities in each of the first battery B1 to the m battery Bm or in the battery array 20. That is, the control unit 120 can determine abnormalities in each of the first battery B1 to the m battery Bm based on at least one of the distribution of adjustment amounts from the first adjustment operation, the second adjustment operation, the third adjustment operation, and the fourth adjustment operation.

[0075] The control unit 120 may be configured to determine, among the first battery B1 to the mth battery Bm, that a battery related to the adjustment amount that falls within the reference range for each adjustment operation is normal, and that any other battery is abnormal.

[0076] If the adjustment amounts of the first battery B1 to the mth battery Bm are all within the standard range, the control unit 120 can determine that the first battery B1 to the mth battery Bm are all normal.

[0077] The control unit 120 may determine that the battery array 20 is normal if the number of adjustment amounts among the adjustment amounts of the first battery B1 to the mth battery Bm that fall outside the reference range is less than a critical value, and otherwise determine that the battery array 20 is abnormal.

[0078] Battery B being normal means that its voltage characteristics and capacity characteristics are at an acceptable level compared to the other batteries in the battery array 20.

[0079] The battery diagnostic device 100 can easily check the status of each of the first battery B1 to the mth battery Bm using the first main adjustment information to the (m-1)th main adjustment information.

[0080] Even when the first battery B1 to the mth battery Bm, connected in series, are charged or discharged with current of the same direction and magnitude, the actual change in capacity of each battery may differ from the change in capacity (integrated current value) calculated by ampere counting, due to the electrochemical characteristics of each battery or the impedance of the charger / discharger.

[0081] The battery diagnostic device 100 can identify the relative abnormal levels of each of the first battery B1 to the mth battery Bm relative to the remaining batteries, based on the first main adjustment information to the (m-1)th main adjustment information generated as a result of adjusting the first comparison voltage profile to the (m-1)th comparison voltage profile based on the reference voltage profile. Therefore, the battery diagnostic device 100 according to one embodiment has the advantage of not requiring a large storage area in the memory 130, as it can easily diagnose the state of battery B without having to pre-record reference data such as temperature in the memory 130.

[0082] As described above, the battery diagnostic device 100 can improve the speed of abnormality diagnosis by performing battery abnormality diagnosis using only a single parameter, voltage behavior, regardless of the temperature of the battery B.

[0083] The control unit 120 is operablely coupled with other components of the battery diagnostic device 100 and can control various operations of the battery diagnostic device 100. The control unit 120 can perform various operations of the battery diagnostic device 100 by executing one or more instructions stored in the memory 130.

[0084] The control unit 120 may be referred to as a "control circuit" or "battery controller," and can be implemented in hardware using at least one of the following: ASICs (application-specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), microprocessors, or other electrical units for performing functions. Furthermore, when the control logic is implemented as software, the control unit 120 can be implemented as a collection of program modules. In this case, the program modules are stored in memory 130 and can be executed by the control unit 120.

[0085] In particular, when the battery diagnostic device 100 according to the present invention is included in the battery pack 10, the battery pack 10 may include a control device referred to as an MCU (Micro Controller Unit) or a BMS (Battery Management System). In this case, the control unit 120 may also be embodied by a component such as an MCU or BMS provided in the battery pack 10. Furthermore, in this specification, the terms "perform" or "configured to" in relation to the operation or function of the control unit 120 may include the meaning of "programmed to do so."

[0086] Figures 3 to 7 are graphs referenced to illustrate the adjustment actions that can be performed to generate an adjusted comparison voltage profile from a comparison voltage profile. In each of the graphs shown in Figures 3 to 7, the X-axis represents capacitance (Ah) and the Y-axis represents voltage (V).

[0087] Referring to Figure 3, the reference voltage profile R and the comparison voltage profile T are shown. The comparison voltage profile T is one of the first to (m-1) comparison voltage profiles. For example, the reference voltage profile R may be the voltage profile of the second battery B2, and the comparison voltage profile T may be the voltage profile of the first battery B1. For the sake of explanation, each voltage profile represents the relationship between the battery capacity and voltage during charging of the battery array 20. Note that the X-axis here represents the integrated current value from a specific point in time (e.g., the time when a diagnostic event occurs), not the remaining battery capacity.

[0088] Since the two batteries (e.g., B1 and B2) are connected in series, the capacity range (exemplified as 0 to 100 Ah in Figure 3) is the same for both the reference voltage profile R and the comparison voltage profile T.

[0089] Referring to Figure 3, it can be seen that the voltage (Vra) at the starting point (RA) of the reference voltage profile R is different from the voltage (Vta) at the starting point (TA) of the comparison voltage profile T. Also, the voltage (Vrb) at the ending point (RB) of the reference voltage profile R is different from the voltage (Vtb) at the ending point (TB) of the comparison voltage profile T. These differences between the two voltage profiles (R, T) are due to differences in characteristics such as the degree of degradation (full charge capacity) and internal resistance of the two batteries (e.g., B1, B2).

[0090] In particular, Figure 3 illustrates a case where the voltage increase rate of the comparison voltage profile T is greater than that of the reference voltage profile R within the same capacity range (0 to 100 Ah). This can be confirmed by the fact that the voltage difference at the end of the capacity range (100 Ah, ΔVe=Vtb-Vrb) is greater than the voltage difference at the start of the capacity range (0 Ah, ΔVs=Vta-Vra). For reference, if the reference voltage profile R is the voltage profile of battery B2 and the comparison voltage profile T is the voltage profile of battery B1, a comparison of the two voltage profiles (R, T) shows that battery B1 has a higher internal resistance or a lower full charge capacity than battery B2. In other words, there is a high possibility that battery B1 is abnormal compared to battery B2.

[0091] Figure 4 is a diagram used to illustrate the first adjustment operation with respect to the comparison voltage profile T shown in Figure 3.

[0092] Since the comparison voltage profile T is located above the reference voltage profile R across the entire capacitance range, shifting the comparison voltage profile T downwards toward the reference voltage profile R should reduce the error between the comparison voltage profile T and the reference voltage profile R.

[0093] The control unit 120 can perform a first adjustment operation in which the reference voltage profile R is fixed and the comparison voltage profile T is shifted in the Y-axis direction. Referring to Figure 4, the adjusted comparison voltage profile T1 is the result of shifting the comparison voltage profile T by ΔV in the Y-axis direction.

[0094] The control unit 120 can determine the amount of adjustment for the first adjustment operation (i.e., the voltage shift factor) that minimizes the error by repeatedly performing a first adjustment operation in which the comparison voltage profile T is shifted by a small amount (e.g., 0.001V) in the Y-axis direction and the amount of error with the reference voltage profile R.

[0095] Figure 5 is a diagram that provides an illustrative explanation of the second adjustment operation with respect to the comparison voltage profile T shown in Figure 3.

[0096] The control unit 120 may perform a second adjustment operation to scale (reduce or expand) the comparison voltage profile T in the Y-axis direction.

[0097] Since the voltage range of the comparison voltage profile T (Vta~Vtb) is larger than the voltage range of the reference voltage profile R (Vra~Vrb), reducing (compressing) the comparison voltage profile T in the Y-axis direction should reduce the amount of error between the comparison voltage profile T and the reference voltage profile R.

[0098] The control unit 120 can determine the amount of adjustment for the second adjustment operation (i.e., the voltage scale factor) that minimizes the error by repeatedly performing a second adjustment operation in which the comparison voltage profile T is reduced by a small ratio (e.g., 0.01%) along the Y axis and the amount of error with the reference voltage profile R.

[0099] In Figure 5, the adjusted comparison voltage profile T2 is the result of scaling the comparison voltage profile T so that the starting point (TA) is fixed while the rest of the profile shrinks along the Y axis. For example, a voltage scale factor of 99% means that the magnitude of the voltage range of the adjusted comparison voltage profile T2 (Vtb2-Vta) is 99% of the magnitude of the voltage range of the comparison voltage profile T (Vtb-Vta). Also, if the voltage of the comparison voltage profile T at a specific capacitance (Qk) is Vq, and the voltage of the adjusted comparison voltage profile T2 is Vq2, then Vq2 is "Vta + (Vq-Vta) × 0.99 [V]".

[0100] Figure 6 is a diagram that provides an illustrative explanation of the third adjustment operation with respect to the comparison voltage profile T shown in Figure 3.

[0101] In Figure 3 above, as the capacitance increases along the X-axis, the voltage difference between the reference voltage profile R and the comparison voltage profile T tends to increase. Therefore, by shifting the comparison voltage profile T to the right along the X-axis, the amount of error between the comparison voltage profile T and the reference voltage profile R should decrease.

[0102] The control unit 120 may perform a third adjustment operation that shifts the comparison voltage profile T in the X-axis direction. Referring to Figure 6, the adjusted comparison voltage profile T3 is the result of shifting the comparison voltage profile T by ΔQ in the Y-axis direction. The starting and ending voltages of the adjusted comparison voltage profile T3 are the same as those of the comparison voltage profile T.

[0103] The control unit 120 can determine the amount of adjustment for the third adjustment operation (i.e., the capacitance shift factor) that minimizes the error by repeatedly performing a third adjustment operation in which the comparison voltage profile T is shifted by a small amount (e.g., 0.01 Ah) in the X-axis direction and the amount of error with the reference voltage profile R.

[0104] Figure 7 is a diagram used to illustrate the fourth adjustment operation with respect to the comparison voltage profile T shown in Figure 3.

[0105] The control unit 120 may perform a fourth adjustment operation that scales (reduces or expands) the comparison voltage profile T in the X-axis direction.

[0106] Because the voltage slope of the comparison voltage profile T is steeper than the voltage slope of the reference voltage profile R, expanding the comparison voltage profile T in the X-axis direction should reduce the amount of error between the comparison voltage profile T and the reference voltage profile R.

[0107] The control unit 120 can determine the amount of adjustment for the fourth adjustment operation (i.e., the capacitance scale factor) that minimizes the error by repeatedly performing a fourth adjustment operation that monitors the amount of error with the reference voltage profile R after expanding the comparison voltage profile T by a small ratio (e.g., 0.01%) along the X axis.

[0108] For example, a capacitance scale factor of 110% means that the capacitance range of the adjusted comparison voltage profile T4 is 1.1 times larger than the capacitance range of the comparison voltage profile T. In Figure 7, the adjusted comparison voltage profile T4 is the result of scaling the comparison voltage profile T so that the starting point (TA) is fixed, and the rest of the profile is expanded by 1.1 times along the X axis. Also, if the capacitance of the comparison voltage profile T at a specific voltage (Vu) is QT, and the capacitance of the adjusted comparison voltage profile T2 is QT4, then QT4 is "1.1 × QT [Ah]".

[0109] When the control unit 120 determines the adjustment amount for the fourth adjustment operation, it does so based on the amount of error in the overlapping portion between the capacitance range of the reference voltage profile R and the capacitance range of the adjusted comparison voltage profile T4. For example, in Figure 7, the capacitance range of the reference voltage profile R is 0 to 100 Ah, while the capacitance range of the adjusted comparison voltage profile T4 is 0 to 110 Ah. Therefore, the adjustment amount for the fourth adjustment operation is determined based on the amount of error in the overlapping portion of the two ranges, from 0 to 100 Ah.

[0110] The process of generating the corresponding adjusted comparison voltage profile from the comparison voltage profile by individually performing the first to fourth adjustment operations with reference to Figures 3 to 7 has been explained above.

[0111] In this regard, for the j-th comparison voltage profile, only the first adjustment operation may be performed, or at least one of the second to fourth adjustment operations may be performed in addition. When generating the j-th adjusted comparison voltage profile from the j-th comparison voltage profile, the order in which two or more of the first to fourth adjustment operations are performed is not limited. For example, when combining the first and second adjustment operations, the second adjustment operation may be performed after the first adjustment operation, or in the reverse order.

[0112] Figure 8 is a diagram used to illustrate the process of calculating the error between the reference voltage profile and the adjusted comparison voltage profile.

[0113] In Figure 8, profile TF illustrates an adjusted comparison voltage profile that has been identified through the adjustment process described above to minimize the error with the reference voltage profile R.

[0114] Referring to Figure 8 along with Figure 3, the comparison voltage profile T and the adjusted comparison voltage profile TF are compared as follows.

[0115] Firstly, the starting point of profile TF (TFA) is located below the starting point of profile T (TA), which indicates that the adjustment amount (voltage shift factor) of the first adjustment operation is a negative value.

[0116] Secondly, if the difference between the voltage at the start point (TFA) and the end point (TFB) of profile TF is smaller than the difference between the voltage at the start point (TA) and the end point (TB) of profile T, it indicates that the adjustment amount (voltage scale factor) of the second adjustment operation is less than 100%.

[0117] Third, since the capacity at the starting point of profile TF (TFA) and the capacity at the starting point of profile T (TA) are equal to 0 Ah, it can be seen that the adjustment amount (capacity shift factor) of the third adjustment operation is 0.

[0118] Fourth, the capacity range of profile TF is wider than the capacity range of profile T, which indicates that the adjustment amount (capacity scale factor) of the fourth adjustment operation is 100% or more.

[0119] The control unit 120 may set the capacitance range of interest to 0 to 100 Ah, which is common to both profile TF and profile R. Subsequently, the control unit 120 may search for the discrepancy between profile TF and profile R within the capacitance range of interest (shaded area in Figure 8) and determine the error amount of profile TF relative to profile R (e.g., RMSE).

[0120] The control unit 120 can calculate the length of the comparison voltage profile T and the length of the adjusted comparison voltage profile TF using a variety of known methods. For example, the control unit 120 can calculate the length of any profile using the following formula 1.

[0121]

number

[0122] In Equation 1, L represents the length of an arbitrary profile, f(x) is a function that represents an arbitrary profile (e.g., a comparison voltage profile, an adjusted comparison voltage profile), and f'(x) is the derivative of f(x). Also, a and b are the lower and upper limits of the capacitance range for which the length is to be calculated.

[0123] The control unit 120 can calculate the lengths of the reference voltage profile R, the comparison voltage profile T, and the adjusted comparison voltage profile TF using Equation 1.

[0124] The control unit 120 may add the ratio of the length of the adjusted comparison voltage profile TF to the length of the comparison voltage profile T to the main adjustment information of the adjusted comparison voltage profile TF.

[0125] Using the method described above, the control unit 120 can perform adjustment operations for each of the first comparison voltage profile to the (m-1) comparison voltage profile and calculate the first main adjustment information to the (m-1) main adjustment information.

[0126] The control unit 120 obtains (m-1) factors related to at least one adjustment operation among the first adjustment operation to the fourth adjustment operation from the first main adjustment information to the (m-1)th main adjustment information, and can diagnose whether there is an abnormality in each of the first battery B1 to the mth battery Bm or in the battery array 20 based on the distribution of the obtained (m-1) factors.

[0127] When diagnosing the battery array 20, the control unit 120 may further utilize the differential information of the reference voltage profile and the first to (m-1)th comparison voltage profiles. Two embodiments for acquiring differential information for each voltage profile will be described below with reference to Figures 9 and 10.

[0128] Figure 9 is a diagram used to illustrate the differential voltage profile generated from the voltage profile. In Figure 9, the X-axis represents capacitance and the Y-axis represents differential voltage (dV / dQ).

[0129] The control unit 120 can generate the i-th differential voltage profile from the i-th voltage profile of the i-th battery Bi. The i-th differential voltage profile is a dataset obtained from the i-th voltage profile, showing the relationship between (i) capacity and (ii) differential voltage (dV / dQ) of the i-th voltage profile. dV / dQ is the ratio of the change in voltage (V) (dV) to the unit capacity (dQ). In other words, the differential voltage (dV / dQ) is the rate of change of voltage with respect to capacity.

[0130] The control unit 120 can generate a reference differential voltage profile from a reference voltage profile, and generate a first comparative differential voltage profile and a (m-1) comparative differential voltage profile from a first comparative voltage profile and a (m-1) comparative voltage profile.

[0131] Referring to Figure 9 along with Figure 3, Profile RDV is an example of a reference differential voltage profile obtained from the reference voltage profile R in Figure 3, and Profile TDV is an example of a comparative differential voltage profile obtained from the comparative voltage profile T in Figure 3.

[0132] The control unit 120 can apply an adjustment process, including at least one of the first to fourth adjustment operations described above with reference to Figures 4 to 7, to the first comparative differential voltage profile to the (m-1) comparative differential voltage profile, thereby obtaining the first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile from the first comparative differential voltage profile to the (m-1) comparative differential voltage profile. In other words, the only difference between a voltage profile and a differential voltage profile is that the units on the Y axis are "voltage (V)" and "differential voltage (dV / dQ)". Therefore, by substituting only the units on the Y axis with respect to the first to fourth adjustment operations as described above, it is possible to obtain the first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile from the first comparative differential voltage profile to the (m-1) comparative differential voltage profile.

[0133] The control unit 120 can generate first sub-adjustment information to the (m-1) sub-adjustment information, indicating the level of adjustment from the first comparative differential voltage profile to the (m-1) comparative differential voltage profile to the first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile. The j-th sub-adjustment information may be a dataset that defines how and to what extent the j-th comparative differential voltage profile was adjusted to generate the j-th adjusted comparative differential voltage profile. In this case, the adjustment amount of the first adjustment operation included in the j-th sub-adjustment information may be called the "differential voltage shift factor," and the adjustment amount of the second adjustment operation may be called the "differential voltage scale factor." The sub-adjustment information obtained from the differential voltage profile may be called "differential voltage curve-based adjustment information."

[0134] Figure 10 is a diagram used to illustrate the differential capacitance profile generated from the voltage profile. In Figure 10, the X-axis represents voltage and the Y-axis represents differential capacitance (dQ / dV).

[0135] The control unit 120 can generate an i-th differential capacitance profile from the i-th voltage profile. The i-th differential capacitance profile is a dataset obtained from the i-th voltage profile, showing the relationship between (i) voltage and (ii) differential capacitance (dQ / dV) of the i-th voltage profile. dQ / dV is the ratio of the change in capacitance (Q) to a unit voltage (dV). In other words, differential capacitance (dQ / dV) is the rate of change of capacitance with respect to voltage.

[0136] The control unit 120 can generate a reference differential capacitance profile from a reference voltage profile, and generate a first comparative differential capacitance profile and a (m-1) comparative differential capacitance profile from a first comparative voltage profile and a (m-1) comparative voltage profile.

[0137] Referring to Figure 10 along with Figure 3, Profile RDQ exemplifies the reference differential capacitance profile obtained from the reference voltage profile R in Figure 3, and Profile TDQ exemplifies the comparative differential capacitance profile obtained from the comparative voltage profile T in Figure 3.

[0138] The control unit 120 can obtain the first adjusted comparative differential capacitance profile and the (m-1) adjusted comparative differential capacitance profile from the first adjusted comparative differential capacitance profile and the (m-1) adjusted comparative differential capacitance profile by applying an adjustment process including at least one of the first to fourth adjustment operations described above with reference to Figures 4 to 7. In other words, the voltage profile and the differential capacitance profile differ only in that the units of the X axis are "capacitance" and "voltage" and the units of the Y axis are "voltage" and "differential capacitance". Therefore, by substituting only the units of the X and Y axes with respect to the first to fourth adjustment operations as described above, it is possible to obtain the first adjusted comparative differential capacitance profile and the (m-1) adjusted comparative differential capacitance profile from the first adjusted comparative differential capacitance profile and the (m-1) adjusted comparative differential capacitance profile.

[0139] The control unit 120 can generate first sub-adjustment information to the (m-1) sub-adjustment information, indicating the level of adjustment from the first comparative differential capacitance profile to the (m-1) comparative differential capacitance profile to the first adjusted comparative differential capacitance profile to the (m-1) adjusted comparative differential capacitance profile. The j-th sub-adjustment information may be a dataset that defines how and to what extent the j-th comparative differential capacitance profile was adjusted to generate the j-th adjusted comparative differential capacitance profile. The sub-adjustment information obtained from the differential capacitance profile may be called "differential capacitance curve-based adjustment information".

[0140] The control unit 120 diagnoses whether there is an abnormality in each of the first to the mth batteries or in the battery array 20, based on the first main adjustment information to the (m-1)th main adjustment information. Depending on the implementation, when the control unit 120 diagnoses an abnormality in each of the first to the mth batteries Bm or in the battery array 20, it may further use the first sub-adjustment information to the (m-1)th sub-adjustment information.

[0141] The following describes an embodiment in which the control unit 120 determines the battery status based on the calculated adjustment information and reference range. For convenience of explanation, Figures 11 to 14 describe a diagnostic method that utilizes the first voltage scale factor to the (m-1) voltage scale factor, which are the result values ​​of the second adjustment operation among the first to fourth adjustment operations. In Figures 11 to 14, the maximum value of the identification number is set to 100, meaning that the battery array 20 contains a total of 100 batteries (B1 to B100).

[0142] The control unit 120 can determine representative values ​​for the first voltage scale factor to the (m-1)th voltage scale factor. The first voltage scale factor to the (m-1)th voltage scale factor are the result of performing the adjustment process described above for each of the first comparison voltage profile to the (m-1)th comparison voltage profile T, and are related to the second adjustment operation. For example, the representative value may be the average or median of the first voltage scale factor to the (m-1)th voltage scale factor.

[0143] The control unit 120 can calculate the standard deviation and mean value as distribution information of the first voltage scale factor to the (m-1)th voltage scale factor, and based on this, set a reference range for diagnosing abnormalities in battery B.

[0144] Specifically, the control unit 120 can determine the reference range such that the median is equal to the representative value, the upper limit is greater than the representative value by a tolerance, and the lower limit is less than the representative value by a tolerance. Here, the tolerance may be equal to the standard deviation, or equal to the standard deviation multiplied by a predetermined positive coefficient.

[0145] As described above, the battery diagnostic device 100 utilizes distribution information to set a reference range, which has the advantage of reducing the possibility of misdiagnosis and improving the accuracy of abnormality diagnosis.

[0146] Figure 11 shows an example of the distribution of voltage scale factors associated with a specific adjustment operation in the adjustment process. In Figure 11, the Y-axis represents the voltage scale factor value, and the X-axis represents the battery identification number.

[0147] Referring to Figure 11, the upper and lower limits of the reference range RR1 are 100.8% and 99.2%, respectively. From this, we can see that the average of the first voltage scale factor to the (m-1) voltage scale factor is (100.8 + 99.2) / 2 = 100.0%, and the tolerance is 0.8%. As mentioned above, 100.0% is also the voltage scale factor related to the reference voltage profile.

[0148] Since the first voltage scale factor to the (m-1)th voltage scale factor are all located within the reference range RR1, the control unit 120 can determine that all of the first battery B1 to the mth battery Bm are normal. Furthermore, since all of the first battery B1 to the mth battery Bm are determined to be normal, the control unit 120 can determine that the battery array 20 is also normal.

[0149] Figure 12 shows another example of the distribution of voltage scale factors related to a specific adjustment operation in the adjustment process. In Figure 12, the Y-axis represents the voltage scale factor value, and the X-axis represents the battery identification number.

[0150] The upper and lower limits of the reference range RR2 shown in Figure 12 are 100.5% and 99.3%, respectively. From this, we can see that the average value of the first voltage scale factor to the (m-1) voltage scale factor is (100.5 + 99.3) / 2 = 99.9%, and the tolerance value is 0.6%. Compared to the reference range RR1 in Figure 11, the average value is 0.1%p smaller and the tolerance value is 0.2%p smaller.

[0151] In Figure 12, unlike in Figure 11, several voltage scale factors fall outside the reference range RR2 of at least one of the multiple adjustment information calculated by the control unit 120.

[0152] The control unit 120 checks the battery identification number associated with the voltage scale factor that falls outside the reference range RR2, and may determine that the battery with the confirmed battery identification number is abnormal. Furthermore, if the number of batteries determined to be abnormal exceeds a critical value, the control unit 120 may determine that the battery array 20 is abnormal.

[0153] Figure 13 shows yet another example of the distribution of voltage scale factors related to a specific adjustment operation in the adjustment process. In Figure 13, the Y axis represents the voltage scale factor value, and the X axis represents the battery identification number.

[0154] The upper and lower limits of the reference range RR3 shown in Figure 13 are 101.0% and 99.0%, respectively. From this, we can see that the average value of the first voltage scale factor to the (m-1) voltage scale factor is (101.0 + 99.0) / 2 = 100.0%, and the tolerance value is 1.0%. Compared to the reference range RR1 in Figure 11, the average value is the same, but the tolerance value has increased by 0.2%p.

[0155] Referring to Figure 13, one of the (m-1) voltage scale factors, voltage scale factor F16 associated with battery identification number 16, is outside the reference range RR3. Therefore, the control unit 120 can determine that the battery with battery identification number 16 is abnormal.

[0156] The control unit 120 can determine the abnormality level of a battery that has been judged to be abnormal. For example, the abnormality level of a battery associated with battery identification number 16 (i.e., B16) may have a predetermined positive correlation (e.g., proportionality) with the deviation of the voltage scale factor F16 associated with battery identification number 16 from the reference range RR3. If the voltage scale factor F16 associated with identification number 16 is smaller than the lower limit of the reference range RR3, the difference between the voltage scale factor F16 and the lower limit of the reference range RR3 can be calculated as the deviation of the voltage scale factor F16. Conversely, if the voltage scale factor F16 is larger than the upper limit of the reference range RR3, the difference between the voltage scale factor F16 and the upper limit of the reference range RR3 can be calculated as the deviation of the voltage scale factor F16. A larger deviation means a higher abnormality level.

[0157] The control unit 120 may set a reference range based on the reference voltage profile R without calculating representative values ​​for multiple main adjustment information. In this case, the selected reference voltage profile R may be the voltage profile of a reference battery in an abnormal state, but even in such a case, the control unit 120 can diagnose the state of battery B. This will be explained with reference to Figure 14.

[0158] Figure 14 shows yet another example of the distribution of voltage scale factors related to a specific adjustment operation in the adjustment process. In Figure 14, the Y axis represents the voltage scale factor value, and the X axis represents the battery identification number.

[0159] Referring to Figure 14, the control unit 120 can diagnose abnormalities in the first battery B1 to the mth battery Bm or the battery array 20 by utilizing a predetermined reference range RR4 for a specific adjustment operation.

[0160] The reference range RR4 relates to the second adjustment action, with a median of 100%, and upper and lower limits of 101.0% and 99.0%, respectively. From this, it can be seen that the tolerance is 1%.

[0161] If only the reference battery among the first battery B1 to the mth battery Bm is abnormal, the first to (m-1)th comparison voltage profiles should have a large deviation from the reference voltage profile R, and the voltage scale factors of the (m-1) batteries B excluding the reference battery should be biased to a range greater than or less than 100%. Figure 14 shows that all voltage scale factors are biased upwards, exceeding the upper limit of 101.0% of the reference range RR4. In this case, the control unit 120 can diagnose whether the reference battery is abnormal based on the number of voltage scale factors that fall outside the reference range RR4 among the (m-1) voltage scale factors. Naturally, if the number of voltage scale factors that fall outside the reference range RR4 (99 in Figure 14) is greater than or equal to a specific value (for example, a natural number greater than or equal to m / 3 and less than m / 3+1), the reference battery may be identified as abnormal.

[0162] The diagnostic process utilizing the voltage scale factor related to the second adjustment operation has been described above with reference to Figures 11 to 14. It goes without saying that the diagnostic process utilizing the distribution of the voltage scale factor related to the second adjustment operation can also be applied to the diagnostic processes utilizing the distribution of the voltage shift factor related to the first adjustment operation, the distribution of the capacitance shift factor related to the third adjustment operation, and the distribution of the capacitance scale factor related to the fourth adjustment operation.

[0163] According to the method described above, the battery diagnostic device 100 can easily diagnose individual battery abnormalities or abnormalities by statistically analyzing the adjustment results obtained for the entire battery, without having to secure reference data to be used for detecting battery abnormalities in advance.

[0164] The battery diagnostic device 100 can identify batteries that have an adjustment amount (e.g., voltage scale factor) that falls outside the reference range. The battery diagnostic device 100 can detect individual batteries that have been pre-assigned identification numbers related to the adjustment amount that falls outside the reference range for each adjustment operation. In this case, it is possible to individually diagnose which of the series-connected batteries B1 to mth battery Bm is in an abnormal state, and subsequent measures such as user notification, suspension of use, or replacement of the abnormal battery can be taken. The battery diagnostic device 100 can also diagnose whether the battery array 20 is abnormal based on the number of batteries determined to be in an abnormal state.

[0165] The adjustment process for the first battery B1 to the mth battery Bm described above may be performed whenever a diagnostic event occurs. For example, the control unit 120 may determine that a diagnostic event has occurred if the elapsed time (time difference) from the completion of the previous charge to the start of the current charge is equal to or greater than a predetermined reference time (e.g., one week) and / or if the cumulative charge / discharge capacity of the battery array 20 during the period from the completion of the previous charge to the start of the current charge is equal to or greater than a predetermined capacity (e.g., the design capacity of the battery array 20). As another example, the control unit 120 may count the number of charge cycles of the battery pack 10 and determine that a diagnostic event has occurred each time the number of charge cycles increases by a predetermined reference number.

[0166] The control unit 120 may select a reference battery for the current diagnostic process based on the results of the previous diagnostic process. A reference battery is a battery whose voltage profile is set to a reference voltage profile.

[0167] For example, if only one of the first to fourth diagnostic operations was performed in the previous diagnostic process, the control unit 120 may select a specific battery as the reference battery in which the adjustment amount of the specific diagnostic operation performed in the previous process was determined to be normal.

[0168] As another example, if at least two of the first to fourth diagnostic operations were performed in the previous diagnostic process, the control unit 120 may select a specific battery as the reference battery in which the adjustment amounts of the two or more adjustment operations performed in the previous process were all determined to be normal.

[0169] As yet another example, if a fourth diagnostic operation was performed in the previous diagnostic process, the control unit 120 may select the battery associated with the capacity scale factor closest to the mean or median among the adjustment amounts of the previous fourth diagnostic operation (i.e., the first capacity scale factor to the (m-1) capacity scale factor) as the reference battery for the current operation.

[0170] As described above, the control unit 120 can optimize the distribution of adjustment amounts obtained for each adjustment operation of the diagnostic process by selecting a reference battery in the current diagnostic process based on the results of the previous diagnostic process.

[0171] If the control unit 120 determined that two or more batteries B were normal in the previous diagnostic process, it may select the battery with the fewest or no history of being selected as a reference battery among the two or more batteries B as the reference battery for the current diagnostic process. For example, among two or more batteries that have no history of being selected as a reference battery, it may select the battery with the smallest or largest identification number as the reference battery.

[0172] On the other hand, battery B has the characteristic that its electrochemical reaction slows down as the temperature decreases. For example, the internal resistance tends to decrease as the battery temperature increases. Taking this into consideration, the control unit 120 can adjust the magnitude of the reference range for at least one of the first to fourth adjustment operations based on the temperature of the battery array 20.

[0173] Specifically, the measurement unit 110 can measure the temperature of the battery array 20. The temperature of the battery array 20 can be treated as representing the average temperature of the first battery B1 to the mth battery Bm.

[0174] The control unit 120 can expand the reference range to correspond to the difference between the measured temperature and the lower limit temperature if the measured temperature is below a predetermined lower limit temperature.

[0175] When the measured temperature exceeds a predetermined upper limit temperature, the control unit 120 may reduce the reference range to correspond to the difference between the measured temperature and the lower limit temperature.

[0176] Let's assume the reference temperature range is +10°C to +30°C. If the measured temperature is +20°C, the control unit 120 can maintain the reference range of 99.0% to 101.0%. If the measured temperature is +1°C, the control unit 120 can expand the reference range to correspond to a temperature difference of 9°C. If the measured temperature is +35°C, the control unit 120 can shrink the reference range to correspond to a temperature difference of 5°C. Here, the median of the reference range (half the sum of the upper and lower limits) can be maintained. Relationship data of the reduction and / or expansion ratios of the reference range according to the temperature difference between the upper and / or lower limits of the reference temperature range and the temperature of the battery array 20 may be created in the form of a lookup table or the like and pre-recorded in the memory 130.

[0177] Figure 15 is an illustrative diagram showing a battery pack according to one embodiment of the present invention, and Figure 16 is an illustrative diagram showing an electric vehicle including the battery pack shown in Figure 15.

[0178] Referring to Figure 15, the battery pack 10 may include a pair of power terminals P+ and P-, a battery array 20, and a battery diagnostic device 100. The battery pack 10 may further include a relay 30 and a fuse 40, etc. The charging and discharging unit 300 may be included in the battery pack 10 or the electric vehicle 1.

[0179] At least some components of the battery diagnostic device 100 according to the present invention may be embodied as conventional components included in the battery pack 10. For example, the measuring unit 110 of the battery diagnostic device 100 according to the present invention may be embodied by a voltage sensor included in the battery pack 10.

[0180] The charge / discharge unit 300 may be configured to charge and / or discharge the battery array 20 in response to commands from the control unit 120. That is, the charge / discharge unit 300 may have only a charging function, or it may have both a charging function and a discharging function. During the process in which the battery array 20 is charged and / or discharged by the charge / discharge unit 300, the measurement unit 110 may measure the voltage and current of each battery B included in the battery array 20.

[0181] Referring to Figure 16, the battery pack 10 can be applied to the electric vehicle 1. That is, the electric vehicle 1 may include the battery diagnostic device 100 according to the present invention as described above. In particular, in the case of the electric vehicle 1, the battery pack 10 as a power source is a very important component, so the battery diagnostic device 100 according to the present invention can be applied more usefully. Of course, the electric vehicle 1 may further include, in addition to the battery pack 10, a vehicle control unit such as an electronic control unit (ECU), a motor, connection terminals, a DC-DC converter, and so on.

[0182] Figure 17 is a schematic flowchart illustrating a battery diagnostic method according to one embodiment of the present invention. The method shown in Figure 17 can be performed by the battery diagnostic device 100 each time a diagnostic event occurs.

[0183] Referring to Figure 17, in step S1710, the control unit 120 collects voltage measurement data from the measurement unit 110, showing the voltage of each of the first battery B1 to the mth battery Bm connected in series, while the battery array 20 is being charged or discharged. In parallel with collecting voltage measurement data, the control unit 120 may also collect current measurement data from the measurement unit 110, showing the current flowing through the battery array 20. In step S1710, if the cumulative capacity reaches a predetermined critical capacity, or if the voltage of at least one of the first battery B1 to the mth battery Bm reaches a predetermined upper limit voltage, the process proceeds from step S1710 to step S1720.

[0184] In step S1720, the control unit 120 generates first to m voltage profiles showing the voltage change history of each of the first battery B1 to the m battery Bm. The i-th voltage profile may be a time series of measured voltages of the i-th battery Bi according to its time or capacity.

[0185] In step S1730, the control unit 120 sets one of the first voltage profile to the mth voltage profile as the reference voltage profile. The remaining (m-1) voltage profiles, excluding the reference voltage profile, can be set to the first comparison voltage profile to the (m-1)th comparison voltage profile.

[0186] In step S1740, the control unit 120 diagnoses the battery array by comparing the first to (m-1) comparison voltage profiles with a reference voltage profile.

[0187] Figure 18 is a flowchart illustrating the subroutines that may be included in step S1740 of Figure 17.

[0188] Referring to Figure 18, step S1740 may include steps S1810 to S1830 as its subroutines.

[0189] In step S1810, the control unit 120 adjusts the first comparison voltage profile to the (m-1)th comparison voltage profile to minimize the error with the reference voltage profile, thereby generating the first adjusted comparison voltage profile to the (m-1)th adjusted comparison voltage profile. Specifically, an adjustment process including at least one of the first to fourth adjustment operations is performed for each of the first to (m-1)th comparison voltage profiles, resulting in the generation of the first adjusted comparison voltage profile to the (m-1)th adjusted comparison voltage profile. In other words, the jth adjusted comparison voltage profile is obtained from the jth comparison voltage profile.

[0190] In step S1820, the control unit 120 generates first main adjustment information to (m-1) main adjustment information indicating the adjustment level from the first comparison voltage profile to the (m-1) comparison voltage profile to the first adjusted comparison voltage profile to the (m-1) adjusted comparison voltage profile. The j-th main adjustment information includes at least one of the following: the j-th voltage shift factor, which is the adjustment amount by the first adjustment operation; the j-th voltage scale factor, which is the adjustment amount by the second adjustment operation; the j-th capacitance shift factor, which is the adjustment amount by the third adjustment operation; and the j-th capacitance scale factor, which is the adjustment amount by the fourth adjustment operation.

[0191] In step S1830, the control unit 120 diagnoses whether each of the first battery B1 to the mth battery Bm or the battery array 20 is abnormal based on the first main adjustment information to the (m-1)th main adjustment information. Specifically, the control unit 120 can detect an abnormality in at least one of the batteries B and the battery array 20 by analyzing the distribution of the adjustment amount of at least one adjustment operation included in the first main adjustment information to the (m-1)th main adjustment information.

[0192] As an example, the control unit 120 can diagnose whether there is an abnormality in each of the first battery B1 to the mth battery Bm or in the battery array 20 based on at least one of the first adjustment operation result dataset, the second adjustment operation result dataset, the third adjustment operation result dataset, and the fourth adjustment operation result dataset.

[0193] Here, the dataset resulting from the first adjustment operation is referred to as the first voltage shift factor to the (m-1)th voltage shift factor. The dataset resulting from the second adjustment operation is referred to as the first voltage scale factor to the (m-1)th voltage scale factor. The dataset resulting from the third adjustment operation is referred to as the first capacitance shift factor to the (m-1)th capacitance shift factor. The dataset resulting from the fourth adjustment operation is referred to as the first capacitance scale factor to the (m-1)th capacitance scale factor.

[0194] Figure 19 is a flowchart showing an example of a subroutine that may be added to step S1740 in Figure 17.

[0195] Referring to Figure 19, step S1740 may include steps S1910 to S1950 as its subroutines. The method in Figure 19 may be executed in parallel with the method in Figure 18, or after the completion of the method in Figure 18.

[0196] In step S1910, the control unit 120 generates a reference differential voltage profile from the reference voltage profile.

[0197] In step S1920, the control unit 120 generates the first comparative differential voltage profile and the (m-1) comparative differential voltage profile from the first comparative voltage profile and the (m-1) comparative voltage profile.

[0198] In step S1930, the control unit 120 adjusts the first comparative differential voltage profile to the (m-1) comparative differential voltage profile, respectively, so as to minimize the error with the reference differential voltage profile, and generates the first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile.

[0199] In step S1940, the control unit 120 generates first sub-adjustment information to (m-1) sub-adjustment information indicating the adjustment level from the first comparative differential voltage profile to the (m-1) comparative differential voltage profile to the first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile.

[0200] In step S1950, the control unit 120 further diagnoses whether each of the first battery B1 to the mth battery Bm or the battery array 20 is abnormal, based on the first sub-adjustment information to the (m-1)th sub-adjustment information based on the differential voltage curve.

[0201] Figure 20 is a flowchart showing another example of a subroutine that may be added to step S1740 in Figure 17.

[0202] Referring to Figure 20, step S1740 may include steps S2010 to S2050 as its subroutines. The method in Figure 20 may be executed in parallel with the method in Figure 18 and / or the method in Figure 19, or after the completion of at least one of the methods in Figure 18 and Figure 19.

[0203] In step S2010, the control unit 120 generates a reference differential capacitance profile from the reference voltage profile.

[0204] In step S2020, the control unit 120 generates the first comparative differential capacitance profile and the (m-1) comparative differential capacitance profile from the first comparative voltage profile and the (m-1) comparative voltage profile.

[0205] In step S2030, the control unit 120 adjusts the first comparative differential capacitance profile to the (m-1) comparative differential capacitance profile, respectively, so as to minimize the error with the reference differential capacitance profile, thereby generating the first adjusted comparative differential capacitance profile to the (m-1) adjusted comparative differential capacitance profile.

[0206] In step S2040, the control unit 120 generates first sub-adjustment information to (m-1) sub-adjustment information indicating the adjustment level from the first comparative differential capacitance profile to the (m-1) comparative differential capacitance profile to the first adjusted comparative differential capacitance profile to the (m-1) adjusted comparative differential capacitance profile. The first sub-adjustment information to (m-1) sub-adjustment information in the method shown in Figure 20 is adjustment information based on a differential capacitance curve, which distinguishes it from the first sub-adjustment information to (m-1) sub-adjustment information in the method shown in Figure 19 described above, which is adjustment information based on a differential voltage curve.

[0207] In step S2050, the control unit 120 diagnoses whether each of the first battery B1 to the mth battery Bm or the battery array 20 is abnormal, based on the first sub-adjustment information to the (m-1)th sub-adjustment information based on the differential capacity curve.

[0208] If all the methods shown in Figures 18 to 20 have been performed, the control unit 120 may ultimately determine each battery that has been diagnosed as abnormal by these methods as an abnormal battery and assign an abnormality confirmation flag to the identification number of the battery that has been determined to be abnormal.

[0209] The control unit 120 may determine a battery that has been diagnosed as abnormal using only one or two of the three methods shown in Figures 18 to 20 to be normal, and may assign a suspected abnormality flag to the identification number of the battery in question.

[0210] The control unit 120 may ultimately determine each battery that has been diagnosed as normal by all three methods shown in Figures 18 to 20 as a normal battery, and may assign a normal confirmation flag to the identification number of the battery that has been determined to be normal.

[0211] The control unit 120 can determine the diagnostic order for the first battery B1 to the mth battery Bm in the current diagnostic process based on the diagnostic flags (abnormality confirmation flag, suspected abnormality flag, or normality confirmation flag) assigned to each of the first battery B1 to the mth battery Bm in the previous diagnostic process. The control unit 120 can diagnose whether a battery with an identification number that was assigned a suspected abnormality flag is abnormal, rather than a battery with an identification number that was assigned a normality confirmation flag in the previous diagnostic process. For example, if the identification number of the first battery B1 was assigned a suspected abnormality flag in the previous diagnostic process and the identification number of the second battery B2 was assigned a normality confirmation flag, the control unit 120 can compare the adjustment amount related to the first battery B1 with the reference range before the adjustment amount related to the second battery B2 to confirm whether the first battery B1 is abnormal.

[0212] The embodiments of the present invention described above are not limited to apparatus and methods, but can also be embodied through a program that implements the functions corresponding to the configuration of the embodiments of the present invention, or through a recording medium on which such a program is recorded. Such embodiments will be easily realized by those skilled in the art from the description of the embodiments described above.

[0213] As described above, the present invention has been explained with limited embodiments and drawings, but it goes without saying that the present invention is not limited thereto, and that various modifications and variations are possible within the equivalent scope of the technical concept and claims of the present invention by persons with ordinary skill in the art to which the present invention pertains.

[0214] Furthermore, the present invention described above can be substituted, modified, and altered in various ways by a person with ordinary skill in the art to which the present invention belongs, without departing from the technical spirit of the invention, and is not limited by the embodiments described above and the accompanying drawings. For diverse modifications, all or part of each embodiment may be selectively combined to form the present invention.

Claims

1. A battery diagnostic device for a battery array including a first battery to the mth battery (where m is a natural number of 3 or greater) connected in series, A sensing unit configured to detect the voltage of each of the first to m batteries, The control unit is configured to generate first to m voltage profiles showing the voltage change history of each of the first to m batteries based on voltage measurement data collected from the sensing unit during charging or discharging of the battery array, The first to mth voltage profiles are curves that show the dependence of the voltage parameters of the first to mth batteries on their capacity, respectively. The control unit, The system is configured to diagnose the battery array by comparing a reference voltage profile, which is one of the first to mth voltage profiles, with the remaining (m-1) voltage profiles other than the reference voltage profile, which are the first to (m-1)th comparison voltage profiles. The aforementioned reference voltage profile is Randomly selected from the first to the mth voltage profiles, The voltage or SOC of each of the first to m voltage profiles is the voltage profile of one battery that is closest to the average of the voltages or SOCs of the first to m batteries. The control unit, The first adjusted comparison voltage profile to the (m-1) adjusted comparison voltage profile are generated by repeatedly performing a first adjustment operation, which consists of at least one of the following: moving the voltage on the voltage axis by applying a voltage shift factor, expanding or contracting the voltage on the voltage axis by applying a voltage scale factor, moving the voltage on the capacitance axis by applying a capacitance shift factor, and expanding or contracting the capacitance axis by applying a capacitance scale factor, so that each of the m-1 error amounts, which represent the deviation between the reference voltage profile and each of the first comparison voltage profile to the (m-1) comparison voltage profile, is minimized. First main adjustment information to the (m-1) main adjustment information indicating the first adjustment level from the first comparison voltage profile to the (m-1) comparison voltage profile, The system is configured to diagnose the battery array based on the first main adjustment information to the (m-1) main adjustment information, The first adjustment level includes at least one of the voltage shift factor, voltage scale factor, capacitance shift factor, and capacitance scale factor indicated by each of the first main adjustment information to the (m-1) main adjustment information, The control unit, The system is configured to determine the sum of squares or mean square error of the difference between the voltage of the j-th adjusted comparison voltage profile (where j is a natural number less than m) among the first adjusted comparison voltage profile to the (m-1) adjusted comparison voltage profile and the voltage of the reference voltage profile as the j-th error amount among the m-1 error amounts. The control unit, The system is configured to determine the jth capacitance scale factor from the jth comparison voltage profile to the jth adjusted comparison voltage profile among the first comparison voltage profile to the (m-1)th comparison voltage profile by repeatedly performing the first adjustment operation described above. The first main adjustment information to the (m-1) main adjustment information, of which the j-th main adjustment information includes the j-th capacity scale factor, The control unit diagnoses that if the j-capacity scale factor is greater than 1, the full charge capacity of the battery corresponding to the j-adjusted comparison voltage profile is less than the full charge capacity of the battery corresponding to the reference voltage profile. Battery diagnostic device.

2. The control unit, The system is configured to determine the jth voltage shift factor from the j-comparison voltage profile to the j-adjusted comparison voltage profile by repeatedly performing the first adjustment operation described above. The battery diagnostic device according to claim 1, wherein the j-th main adjustment information among the first to (m-1) main adjustment information includes the j-th voltage shift factor.

3. The control unit, The system is configured to diagnose abnormalities in each of the first batteries to the m-th batteries or the battery array based on the degree to which the m-1 distributions of the first voltage shift factors to the (m-1) voltage shift factors of the first main adjustment information to the (m-1) main adjustment information are included in the shift factor of the reference range. The aforementioned reference range is determined based on the standard deviation and mean value of the first voltage shift factor to the (m-1) voltage shift factor. The aforementioned abnormality is that the battery array includes batteries with high internal resistance or batteries with low full charge capacity. The battery diagnostic device according to claim 2.

4. The control unit, The system is configured to determine the jth voltage scale factor from the j-comparison voltage profile to the j-adjusted comparison voltage profile by repeatedly performing the first adjustment operation described above. The battery diagnostic device according to claim 1, wherein the j-th main adjustment information among the first to (m-1) main adjustment information includes the j-th voltage scale factor.

5. The control unit, The system is configured to diagnose abnormalities in each of the first batteries to the m-th batteries or the battery array based on the degree to which the m-1 distributions of the first voltage scale factors to the (m-1) voltage scale factors of the first main adjustment information to the (m-1) main adjustment information are included in the scale factor of the reference range. The aforementioned reference range is determined based on the standard deviation and mean value of the first voltage scale factor to the (m-1) voltage scale factor. The aforementioned abnormality is that the battery array includes batteries with high internal resistance or batteries with low full charge capacity. The battery diagnostic device according to claim 4.

6. The control unit, From the aforementioned reference voltage profile, a reference differential voltage profile is generated, which is a curve showing the capacitance dependence of the differential value of the voltage value with respect to capacitance. From each of the first to (m-1) comparison voltage profiles, the first to (m-1) comparison differential voltage profiles are generated, which are curves showing the capacitance dependence of the derivative of each voltage value with respect to capacitance. The first comparative differential voltage profile to the (m-1) comparative differential voltage profile are adjusted by repeatedly performing at least one of the following second adjustment operations: moving the differential voltage profile on the differential voltage axis by applying a differential voltage shift factor, expanding or contracting the differential voltage profile on the differential voltage axis by applying a differential voltage scale factor, moving the differential voltage profile on the capacitance axis by applying a second capacitance shift factor, and expanding or contracting the differential voltage profile on the capacitance axis, so that each of the m-1 second error amounts of the differential voltage, which are amounts indicating the deviation of the reference differential voltage profile from the first comparative differential voltage profile to the (m-1) comparative differential voltage profile, is minimized, thereby generating the first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile. First sub-adjustment information to (m-1) sub-adjustment information indicating a second adjustment level from the first comparative differential voltage profile to the (m-1) comparative differential voltage profile to the first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile is generated. Based on the first sub-adjustment information to the (m-1) sub-adjustment information, the system is configured to diagnose abnormalities in each of the first batteries to the m-th batteries or in the battery array. The second adjustment level includes at least one of the differential voltage shift factor, the differential voltage scale factor, the second capacitance shift factor, and the second capacitance scale factor, as indicated by each of the first sub-adjustment information to the (m-1) sub-adjustment information. The control unit, The second sum of squares or second mean square error of the difference between the differential voltage of the j-th adjusted comparative differential voltage profile (where j is a natural number less than m) among the first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile and the differential voltage of the reference differential voltage profile is determined as the j-th differential voltage error amount among the m-1 second error amounts. The system is configured to determine the j-th differential voltage shift factor or j-th differential voltage scale factor from the j-th comparative differential voltage profile to the j-th adjusted comparative differential voltage profile by repeatedly performing the second adjustment operation described above. The first sub-adjustment information to the (m-1) sub-adjustment information, the j-th sub-adjustment information, includes the j-th differential voltage shift factor or the j-th differential voltage scale factor. The control unit, Based on the degree to which the m-1 distributions of the first differential voltage shift factor to the (m-1) differential voltage shift factor of the first sub-adjustment information to the (m-1) sub-adjustment information are included in the shift factor of the second reference range, or Based on the degree to which the m-1 distributions of the first differential voltage scale factor to the (m-1) differential voltage scale factor of the first sub-adjustment information to the (m-1) sub-adjustment information are included in the scale factor of the third reference range It is configured to diagnose abnormalities in each of the first to mth batteries or the battery array, The second reference range is determined based on the standard deviation and mean value of the first differential voltage shift factor to the (m-1) differential voltage shift factor. The third reference range is determined based on the standard deviation and mean value of the first differential voltage scale factor to the (m-1) differential voltage scale factor. The aforementioned abnormality is that the battery array includes batteries with high internal resistance or batteries with low full charge capacity. The battery diagnostic device according to claim 1.

7. A battery pack comprising a battery diagnostic device according to any one of claims 1 to 6.

8. An electric vehicle comprising the battery pack described in claim 7.

9. A battery diagnostic method for a battery array including a first battery to the mth battery (where m is a natural number of 3 or greater) connected in series, The steps include: collecting voltage measurement data indicating the voltage of each of the first to m batteries during charging or discharging of the battery array; Based on the voltage measurement data, the steps include generating first to m voltage profiles that show the voltage change history of each of the first to m batteries, The process includes the step of diagnosing the battery array by comparing a reference voltage profile, which is one of the first to m-th voltage profiles, with the remaining (m-1) voltage profiles other than the reference voltage profile, which are the first to (m-1) comparison voltage profiles, respectively. The first to mth voltage profiles are curves that show the dependence of the voltage parameters of the first to mth batteries on their capacity, respectively. The aforementioned reference voltage profile is Randomly selected from the first to the mth voltage profiles, The voltage or SOC of each of the first to m voltage profiles is the voltage profile of one battery that is closest to the average of the voltages or SOCs of the first to m batteries. The aforementioned battery diagnostic method is: The first adjusted comparison voltage profile to the (m-1) adjusted comparison voltage profile is generated by repeatedly performing an adjustment operation which includes at least one of the following: moving the reference voltage profile with a voltage shift factor, expanding or contracting the voltage axis with a voltage scale factor, moving the capacitance axis with a capacitance shift factor, and expanding or contracting the capacitance axis with a capacitance scale factor, so that each of the m-1 error amounts, which are amounts indicating the deviation between the reference voltage profile and each of the first comparison voltage profile to the (m-1) comparison voltage profile, is minimized. A step of generating first main adjustment information to the (m-1) main adjustment information indicating the first adjustment level from the first comparison voltage profile to the (m-1) comparison voltage profile, The process further includes a step of diagnosing the battery array based on the first main adjustment information to the (m-1) main adjustment information, The first adjustment level includes at least one of the voltage shift factor, voltage scale factor, capacitance shift factor, and capacitance scale factor indicated by each of the first main adjustment information to the (m-1) main adjustment information, The aforementioned battery diagnostic method is: A step of determining the sum of squares or mean square error of the difference between the voltage of the j-th adjusted comparison voltage profile (where j is a natural number less than m) among the first adjusted comparison voltage profile to the (m-1) adjusted comparison voltage profile and the voltage of the reference voltage profile as the j-th error amount among the m-1 error amounts, The process further includes a step of determining the jth capacitance scale factor from the jth comparison voltage profile to the jth adjusted comparison voltage profile among the first comparison voltage profile to the (m-1) comparison voltage profile, by repeating the adjustment operation described above. The first main adjustment information to the (m-1) main adjustment information, of which the j-th main adjustment information includes the j-th capacity scale factor, The aforementioned battery diagnostic method is: If the j-capacity scale factor is greater than 1, the step further includes diagnosing that the full charge capacity of the battery corresponding to the j-adjusted comparison voltage profile is less than the full charge capacity of the battery corresponding to the reference voltage profile. Battery diagnostic methods.

10. The steps include generating a reference differential voltage profile from the aforementioned reference voltage profile, which is a curve showing the capacitance dependence of the differential value of the voltage value with respect to capacitance, The steps include generating a first comparative differential voltage profile to the (m-1) comparative differential voltage profile, which is a curve showing the capacitance dependence of the derivative of each voltage value with respect to capacitance, from each of the first comparative voltage profile to the (m-1) comparative voltage profile, The first step of generating the first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile by repeatedly performing a second adjustment operation, which is at least one of the following: moving the differential voltage on the differential voltage axis by applying a differential voltage shift factor, expanding or contracting the differential voltage on the differential voltage axis by applying a differential voltage scale factor, moving the differential voltage on the capacitance axis by applying a second capacitance shift factor, and expanding or contracting the differential voltage on the capacitance axis, so that each of the m-1 second error amounts of the differential voltage, which are amounts indicating the deviation of the reference differential voltage profile from the first comparative differential voltage profile to the (m-1) comparative differential voltage profile, is minimized. The process further includes the step of generating first sub-adjustment information to (m-1) sub-adjustment information indicating a second adjustment level from the first comparative differential voltage profile to the (m-1) comparative differential voltage profile to the first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile, The second adjustment level includes at least one of the differential voltage shift factor, the differential voltage scale factor, the second capacitance shift factor, and the second capacitance scale factor, as indicated by each of the first sub-adjustment information to the (m-1) sub-adjustment information. The step of diagnosing the aforementioned battery array is: A step of determining the second sum of squares or second mean square error of the difference between the differential voltage of the j-th adjusted comparative differential voltage profile (where j is a natural number less than m) among the first adjusted comparative differential voltage profile to the (m-1) adjusted comparative differential voltage profile and the differential voltage of the reference differential voltage profile, as the j-th differential voltage error amount among the m-1 second error amounts, The process includes the step of repeatedly performing the second adjustment operation described above to determine the j-th differential voltage shift factor or j-th differential voltage scale factor from the j-th comparative differential voltage profile among the first comparative differential voltage profile to the (m-1) comparative differential voltage profile to the j-th adjusted comparative differential voltage profile, The first sub-adjustment information to the (m-1) sub-adjustment information, the j-th sub-adjustment information, includes the j-th differential voltage shift factor or the j-th differential voltage scale factor. The step of diagnosing the aforementioned battery array is: Based on the degree to which the m-1 distributions of the first differential voltage shift factor to the (m-1) differential voltage shift factor of the first sub-adjustment information to the (m-1) sub-adjustment information are included in the shift factor of the second reference range, or Based on the degree to which the m-1 distributions of the first differential voltage scale factor to the (m-1) differential voltage scale factor of the first sub-adjustment information to the (m-1) sub-adjustment information are included in the scale factor of the third reference range This includes a step of diagnosing an abnormality in each of the first to mth batteries or the battery array, The second reference range is determined based on the standard deviation and mean value of the first differential voltage shift factor to the (m-1) differential voltage shift factor. The third reference range is determined based on the standard deviation and mean value of the first differential voltage scale factor to the (m-1) differential voltage scale factor. The aforementioned abnormality is that the battery array includes batteries with high internal resistance or batteries with low full charge capacity. The battery diagnostic method according to claim 9.

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