Apparatus and method for diagnosing battery

Abstract

A battery diagnostic device according to one embodiment of the present invention includes: a voltage measuring unit configured to measure the voltage of a plurality of batteries; and a control unit configured to calculate the voltage deviation of the plurality of batteries according to the measured voltages, calculate the voltage deviation change amount of each of the plurality of batteries based on the calculated voltage deviation, compare the voltage deviation change amount of each of the plurality of batteries with a preset reference change amount, and diagnose the state of each of the plurality of batteries according to the comparison result.

Description

Technology Field

[0001] The present invention relates to a battery diagnostic device and method, and more specifically, to a battery diagnostic device and method capable of diagnosing an internal micro-short circuit of a battery. Background Technology

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

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

[0005] Energy storage devices utilizing such batteries may be devices that store large amounts of power and provide the stored power to multiple load facilities. For example, energy storage devices are used in forms such as industrial, building, or residential energy management systems, and provide the stored power to load facilities at their respective locations to serve as a regular power grid and / or emergency power grid.

[0006] If a micro-short circuit occurs inside a battery, it leads to a problem of leakage current. For example, let's assume that multiple batteries are included in a battery pack. If a micro-short circuit occurs in one battery and generates leakage current, the voltage of that battery may gradually drop compared to the voltages of the other batteries. Furthermore, if this phenomenon persists, a hard short circuit may occur, potentially causing permanent damage to the battery pack.

[0007] Therefore, it is necessary to develop technology capable of diagnosing in advance whether a micro-short circuit has occurred inside the battery. The problem to be solved

[0008] The present invention was devised to solve the above-mentioned problems and aims to provide a battery diagnostic device and method capable of diagnosing whether an internal micro-short circuit has occurred in a battery.

[0009] Other objects and advantages of the present invention may be understood from the following description and will become more clearly apparent from the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. means of solving the problem

[0010] A battery diagnostic device according to one aspect of the present invention may include: a voltage measuring unit configured to measure the voltage of a plurality of batteries; and a control unit configured to calculate the voltage deviation of the plurality of batteries according to the measured voltages, calculate the voltage deviation change amount of each of the plurality of batteries based on the calculated voltage deviation, compare the voltage deviation change amount of each of the plurality of batteries with a preset reference change amount, and diagnose the state of each of the plurality of batteries according to the comparison result.

[0011] The control unit may be configured to calculate the amount of change in voltage deviation of each of the plurality of batteries based on the difference between the voltage deviation calculated at the current time and the previous voltage deviation calculated at the previous time.

[0012] The control unit may be configured to calculate the voltage deviation change amount by normalizing the difference between the voltage deviation and the previous voltage deviation with respect to the difference between the current time point and the previous time point.

[0013] The control unit may be configured to calculate the difference in voltage deviation by calculating the difference between the voltage deviation and the previous voltage deviation, calculate the difference in time points by calculating the difference between the current time point and the previous time point, and calculate the change in voltage deviation for a unit time point by dividing the difference in voltage deviation by the difference in time points.

[0014] The above control unit may be configured to diagnose the state of a battery as abnormal if the voltage deviation change amount is greater than or equal to the reference change amount.

[0015] The control unit above may be configured to diagnose the state of a battery in which the voltage deviation change amount is less than the reference change amount as a normal state.

[0016] The control unit may be configured to calculate the number of times the voltage deviation change amount is greater than or equal to the reference change amount, and to diagnose the state of the battery as abnormal when the calculated number reaches a preset reference number.

[0017] The above control unit may be configured to diagnose that an internal micro-short circuit has occurred in the battery diagnosed as being in an abnormal state.

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

[0019] An automobile according to another aspect of the present invention may include a battery diagnostic device according to one aspect of the present invention.

[0020] A battery diagnostic method according to another aspect of the present invention may include: a voltage measurement step for measuring the voltage of a plurality of batteries; a voltage deviation calculation step for calculating the voltage deviation of the plurality of batteries according to the voltages measured in the voltage measurement step; a voltage deviation change amount calculation step for calculating the voltage deviation change amount of each of the plurality of batteries based on the voltage deviation calculated in the voltage deviation calculation step; a comparison step for comparing the voltage deviation change amount of each of the plurality of batteries with a preset reference change amount; and a diagnostic step for diagnosing the state of each of the plurality of batteries according to the comparison result of the comparison step. Effects of the invention

[0021] According to one aspect of the present invention, a battery diagnostic device can diagnose the condition of each of a plurality of batteries by tracking the trend of changes in the voltage deviation of the batteries. Specifically, the battery diagnostic device can rapidly diagnose the presence or absence of internal micro-short circuits in each of the plurality of batteries.

[0022] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description in the claims. Brief explanation of the drawing

[0023] The following drawings attached to this specification serve to further enhance understanding of the technical concept of the invention in conjunction with the detailed description of the invention set forth below; therefore, the invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is a schematic diagram illustrating a battery diagnostic device according to one embodiment of the present invention. FIG. 2 is a schematic diagram illustrating the voltage of a plurality of battery cells according to one embodiment of the present invention. FIG. 3 is a schematic diagram illustrating the change in voltage deviation according to one embodiment of the present invention. FIG. 4 is a schematic diagram illustrating a diagnostic embodiment according to one embodiment of the present invention. FIG. 5 is a drawing illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention. FIG. 6 is a schematic drawing illustrating an automobile according to another embodiment of the present invention. FIG. 7 is a schematic diagram illustrating a battery diagnostic method according to another embodiment of the present invention. Specific details for implementing the invention

[0024] Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0025] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0026] In addition, in describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the invention, such detailed description is omitted.

[0027] Terms including ordinal numbers, such as first, second, etc., are used for the purpose of distinguishing one of the various components from the rest, and are not used to limit the components by such terms.

[0028] Throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0029] Additionally, throughout the specification, when it is said that a part is "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other components in between.

[0031] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0032] FIG. 1 is a schematic diagram illustrating a battery diagnostic device (100) according to one embodiment of the present invention.

[0033] Referring to FIG. 1, the battery diagnostic device (100) may include a voltage measuring unit (110) and a control unit (120).

[0034] In the following description, a battery refers to a single, independent cell that is physically separable and equipped with a negative terminal and a positive terminal. As an example, a lithium-ion battery or a lithium-polymer battery may be considered a battery. Additionally, a battery may refer to a battery module in which multiple cells are connected in series and / or parallel. For convenience of explanation, the term battery is described below as referring to a single, independent cell.

[0035] The voltage measuring unit (110) can be configured to measure the voltage of a plurality of batteries.

[0036] Specifically, the voltage measuring unit (110) may be configured to measure the voltage of each of the plurality of batteries. Preferably, the voltage measuring unit (110) may measure the open circuit voltage (OCV) of each of the plurality of batteries. For example, the voltage measuring unit (110) may measure the open circuit voltage of the plurality of batteries when the charging or discharging of the plurality of batteries is finished and the rest time has elapsed.

[0037] FIG. 2 is a schematic diagram illustrating the voltage of a plurality of battery cells according to one embodiment of the present invention.

[0038] In the embodiment of FIG. 2, it is assumed that a first battery (Ba), a second battery (Bb), a third battery (Bc), and a fourth battery (Bd) are provided. The voltage measuring unit (110) can measure the voltage of the first battery (Ba) as Va, the voltage of the second battery (Bb) as Vb, the voltage of the third battery (Bc) as Vc, and the voltage of the fourth battery (Bd) as Vd.

[0039] Additionally, the voltage measuring unit (110) can be connected to communicate with the control unit (120). For example, the voltage measuring unit (110) and the control unit (120) can be connected via wired and / or wireless connections. The voltage measuring unit (110) can transmit information about the measured voltage to the control unit (120).

[0040] The control unit (120) may be configured to calculate the voltage deviation of a plurality of batteries according to a plurality of measured voltages.

[0041] Specifically, the control unit (120) receives voltage information of a plurality of batteries from the voltage measuring unit (110) and can calculate the voltage deviation of the plurality of batteries based on the received voltage information.

[0042] First, the control unit (120) may be configured to calculate the average voltage of a plurality of batteries. In the embodiment of FIG. 2, the control unit (120) may calculate the average voltage for the voltages of the first to fourth batteries (Ba, Bb, Bc, Bd). For example, the control unit (120) may calculate the average voltage as Vavg by calculating the formula "(Va+Vb+Vc+Vd)÷4".

[0043] Next, the control unit (120) may be configured to calculate the difference between the calculated average voltage and the voltage of each of the plurality of batteries to calculate the voltage deviation of each of the plurality of batteries. In the embodiment of FIG. 2, the control unit (120) may calculate the difference between the voltage of the first to fourth batteries (Ba, Bb, Bc, Bd) and the average voltage to calculate the voltage deviation of the first to fourth batteries (Ba, Bb, Bc, Bd). For example, the control unit (120) may calculate the voltage deviation of the first battery (Ba) as dVa by calculating the formula "|Va-Vavg|" and calculate the voltage deviation of the second battery (Bb) as dVb by calculating the formula "|Vb-Vavg|". And, the control unit (120) can calculate the voltage deviation of the third battery (Bc) as dVc by calculating the formula "|Vc-Vavg|" and calculate the voltage deviation of the fourth battery (Bd) as dVd by calculating the formula "|Vd-Vavg|". Here, "||" is an absolute value symbol, and the calculated voltage deviation can be expressed as the absolute value of the difference between the battery voltage and the average voltage.

[0044] The control unit (120) may be configured to calculate the amount of voltage deviation change for each of the plurality of batteries based on the calculated voltage deviation.

[0045] Specifically, the control unit (120) may be configured to calculate the voltage deviation change amount of each of the plurality of batteries based on the difference between the voltage deviation calculated at the current time and the previous voltage deviation calculated at the previous time. For example, the control unit (120) may calculate the voltage deviation and the voltage deviation change amount of each of the plurality of batteries whenever the voltage of the plurality of batteries is measured by the measurement unit (110). Here, when the voltage deviation of the plurality of batteries is calculated for the first time, the calculation of the voltage deviation change amount may be omitted because there is no voltage deviation calculated at the previous time.

[0046] FIG. 3 is a schematic diagram illustrating the change in voltage deviation according to an embodiment of the present invention. Specifically, the embodiment of FIG. 3 is a diagram illustrating only the voltage deviation of the first battery (Ba) among the voltage deviations of the first to fourth batteries (Ba, Bb, Bc, Bd) calculated at time points D1, D2, D3, and D4.

[0047] For example, in the embodiment of FIG. 3, D1, D2, D3, and D4 represent the time when the voltage of the first battery (Ba) is measured. Specifically, D1, D2, D3, and D4 represent the day when the voltage of the first battery (Ba) is measured. Here, the intervals of D1, D2, D3, and D4 may be the same or different. That is, it should be noted that the intervals of D1, D2, D3, and D4 are not limited to a predetermined period.

[0048] Meanwhile, it should be noted that although only the voltage deviation of the first battery (Ba) is shown in FIG. 3, the voltage deviation of the second to fourth batteries (Bb, Bc, Bd) was also calculated for the diagnosis of the condition of the second to fourth batteries (Bb, Bc, Bd).

[0049] In the embodiment of FIG. 3, the first voltage deviation of the first battery (Ba) calculated at time D1 is dV1, the second voltage deviation of the first battery (Ba) calculated at time D2 is dV2, the third voltage deviation of the first battery (Ba) calculated at time D3 is dV3, and the fourth voltage deviation of the first battery (Ba) calculated at time D4 is dV4. The control unit (120) can calculate the difference in voltage deviation at consecutive time points to calculate the amount of change in voltage deviation for the first battery (Ba). The control unit (120) can calculate the difference between the voltage deviations at time D1 and time D2 according to the formula "dV2-dV1" and calculate the amount of change in second voltage deviation corresponding to time D2 as △dV2. The control unit (120) can calculate the difference between the voltage deviations at time D2 and time D3 according to the formula "dV3-dV2" and calculate the third voltage deviation change amount corresponding to time D3 as △dV3. The control unit (120) can calculate the difference between the voltage deviations at time D4 and time D3 according to the formula "dV4-dV3" and calculate the fourth voltage deviation change amount corresponding to time D4 as △dV4.

[0050] The control unit (120) may be configured to compare the voltage deviation change amount of each of the plurality of batteries with a preset reference change amount. Additionally, the control unit (120) may be configured to diagnose the state of each of the plurality of batteries based on the comparison result.

[0051] Here, the reference change amount can be set by considering the characteristics of the battery. Specifically, the reference change amount can be set by considering the battery shape (cylindrical, pouch, and prismatic, etc.), internal materials (anode, cathode, separator, and electrolyte, etc.), and specifications. For example, the reference change amount can be set based on the change in voltage deviation when an internal micro-short circuit occurs in the reference battery (set to correspond to the battery being diagnosed).

[0052] The control unit (120) can compare the magnitude between the voltage deviation change amount of each of the plurality of batteries and the reference change amount. For example, in the embodiment of FIG. 3, the control unit (120) can diagnose the state of the battery at time D2 by comparing the second voltage deviation change amount (△dV2) at time D2 with the reference change amount. The control unit (120) can diagnose the state of the battery at time D3 by comparing the third voltage deviation change amount (△dV3) at time D3 with the reference change amount. The control unit (120) can diagnose the state of the battery at time D4 by comparing the fourth voltage deviation change amount (△dV4) at time D4 with the reference change amount.

[0053] Additionally, the control unit (120) may be configured to diagnose the state of a battery in which the voltage deviation change amount is greater than or equal to a reference change amount as an abnormal state. Conversely, the control unit (120) may be configured to diagnose the state of a battery in which the voltage deviation change amount is less than a reference change amount as a normal state.

[0054] FIG. 4 is a schematic diagram illustrating a diagnostic embodiment according to one embodiment of the present invention. Specifically, the embodiment of FIG. 4 is an embodiment in which the voltage deviation change amount (△dV2, △dV3, △dV4) of the first battery according to the embodiment of FIG. 3 is compared with a reference change amount (TH).

[0055] For example, in the embodiment of FIG. 4, since the second voltage deviation change amount (△dV2) and the third voltage deviation change amount (△dV3) are smaller than the reference change amount (TH), the control unit (120) can diagnose the state of the battery as normal at time D2 and time D3. Since the fourth voltage deviation change amount (△dV4) is larger than the reference change amount (TH), the control unit (120) can diagnose the state of the battery as abnormal at time D4.

[0056] A battery diagnostic device (100) according to one embodiment of the present invention has the advantage of being able to immediately diagnose the state of a battery by considering the amount of change in voltage deviation from the previous point in time at each diagnostic point in time. That is, the battery diagnostic device (100) has the advantage of being able to quickly diagnose the state of a battery even without considering long-term trends regarding changes in the state of the battery.

[0057] In addition, the battery diagnostic device (100) primarily determines the relative voltage behavior (voltage deviation) of a plurality of batteries and secondarily determines the change in relative voltage behavior (amount of change in voltage deviation) over time for each battery. That is, since the battery diagnostic device (100) diagnoses the condition of a plurality of batteries by considering both the relative voltage behavior of a plurality of batteries and the change in voltage behavior of each battery, it has the advantage of being able to diagnose the condition of a plurality of batteries more accurately.

[0059] Meanwhile, the control unit (120) provided in the battery diagnostic device (100) may optionally include a processor, an ASIC (application-specific integrated circuit), another chipset, a logic circuit, a register, a communication modem, a data processing device, etc., known in the art, to execute various control logics performed in the present invention. Additionally, when the control logic is implemented in software, the control unit (120) may be implemented as a set of program modules. In this case, the program modules may be stored in memory and executed by the control unit (120). The memory may be located inside or outside the control unit (120) and may be connected to the control unit (120) by various well-known means.

[0060] Additionally, the battery diagnostic device (100) may further include a storage unit (130). The storage unit (130) may store data or programs necessary for each component of the battery diagnostic device (100) to perform operations and functions, or data generated during the process of performing operations and functions. The storage unit (130) is not subject to any special restrictions on its type as long as it is a known information storage means capable of recording, erasing, updating, and reading data. As an example, the information storage means may include RAM, flash memory, ROM, EEPROM, registers, etc. Additionally, the storage unit (130) may store program codes in which processes executable by the control unit (120) are defined.

[0062] The control unit (120) may be configured to calculate the amount of change in voltage deviation by normalizing the difference between the voltage deviation and the previous voltage deviation with respect to the difference between the current time point and the previous time point.

[0063] Specifically, the control unit (120) can diagnose the condition of multiple batteries at the time when the measurement unit (110) measures the voltage of multiple batteries. Here, if the measurement unit (110) measures the voltage non-periodically, the difference between the previous time point and the current time point may not be constant. In addition, if the measurement unit (110) measures the voltage periodically but the measurement period is too long, the change in voltage deviation of each of the multiple batteries is bound to increase. Therefore, the control unit (120) can diagnose the condition of multiple batteries more accurately by calculating the change in voltage deviation per unit time point for each of the multiple batteries.

[0064] The control unit (120) may be configured to calculate the difference in voltage deviation by calculating the difference between the voltage deviation and the previous voltage deviation. For example, in the embodiment of FIG. 3, the control unit (120) may calculate the difference between the first voltage deviation (dV1) and the second voltage deviation (dV2) at time D2 to calculate the second voltage deviation change amount (△dV2).

[0065] The control unit (120) may be configured to calculate the difference in time points by calculating the difference between the current time point and the previous time point. For example, in the embodiment of FIG. 3, the control unit (120) may calculate the difference in time points (dD12) between time point D2 and time point D1.

[0066] The control unit (120) may be configured to calculate the amount of voltage deviation change for a unit time point by dividing the difference in voltage deviation by the difference in time point. For example, in the embodiment of FIG. 3, the control unit (120) can calculate the amount of voltage deviation change for a unit time point by calculating the formula “second voltage deviation change amount (△dV2) ÷ difference in time point (D2-D1)”. The control unit (120) can calculate the third voltage deviation change amount for a unit time point by calculating the formula “third voltage deviation change amount (△dV3) ÷ difference in time point (D3-D2)”. The control unit (120) can calculate the fourth voltage deviation change amount for a unit time point by calculating the formula “fourth voltage deviation change amount (△dV4) ÷ difference in time point (D4-D3)”. If time points D1, D2, D3, and D4 are time points related to a day, the control unit (120) can calculate the daily voltage deviation change amount.

[0067] Since the battery diagnostic device (100) diagnoses the state of the battery based on the amount of voltage deviation change per unit time point, it can reduce the possibility of misdiagnosis of the battery state caused by the time difference between the previous time point and the current time point.

[0069] The control unit (120) may be configured to calculate the number of times the voltage deviation change amount is greater than or equal to a reference change amount. Additionally, the control unit (120) may be configured to diagnose the state of the battery as abnormal when the calculated number reaches a preset reference number.

[0070] Here, the reference count is set to prevent the battery condition from being incorrectly diagnosed. For example, the reference count can be set to 3 times. In this case, the control unit (120) can diagnose the battery condition as abnormal when the number of times the voltage deviation change amount is greater than or equal to the reference change amount reaches 3 times.

[0071] For example, the voltage of multiple batteries may be inaccurate due to measurement noise, etc. If the condition of the battery is diagnosed based on inaccurate voltage, there is a risk that the condition of the battery may be incorrectly diagnosed. Therefore, to prevent the condition of the battery from being incorrectly diagnosed due to unexpected noise, etc., the battery diagnostic device (100) may diagnose the condition of the battery by further considering the number of times the voltage deviation change amount is greater than or equal to a reference change amount.

[0073] The control unit (120) may be configured to diagnose that an internal micro-short circuit has occurred in the battery diagnosed as being in an abnormal state.

[0074] Generally, the occurrence of internal micro-short circuits can be determined by observing the battery's voltage behavior over an extended period. In other words, the battery's condition is diagnosed by considering long-term trends in battery voltage. This is because internal micro-short circuits are difficult to identify immediately through the voltage behavior of a single battery. However, internal micro-short circuits worsen as the battery is used, and intensified internal short circuits can cause performance degradation and damage to the battery.

[0075] The battery diagnostic device (100) has the advantage of being able to quickly diagnose the condition of the battery without checking the long-term voltage behavior of each battery by considering the voltage difference between multiple batteries and the amount of change in voltage difference of each battery. That is, the battery diagnostic device (100) has the advantage of being able to prevent problems such as performance degradation or hard short circuits in the battery from occurring in unexpected situations by quickly diagnosing the condition of the battery.

[0077] In one embodiment, the control unit (120) can cut off the electrical connection between the battery diagnosed as being in an abnormal state (hereinafter, abnormal battery) and the battery diagnosed as being in a normal state (hereinafter, normal battery). That is, the control unit (120) can electrically separate the abnormal battery from the normal battery due to a micro internal short circuit. For example, the control unit (120) can control a switching element, etc. corresponding to the abnormal battery to a turned-off state. As another example, the control unit (120) can blow a fuse, etc. corresponding to the abnormal battery.

[0078] In another embodiment, the control unit (120) can output information about the abnormal battery to the outside. For example, the control unit (120) can output information about the abnormal battery to an external display device or alarm device. Thus, a user, etc., can quickly access information about the abnormal battery.

[0080] The battery diagnostic device (100) according to the present invention may be applied to a Battery Management System (BMS). That is, the BMS according to the present invention may include the battery diagnostic device (100) described above. In this configuration, at least some of the components of the battery diagnostic device (100) may be implemented by supplementing or adding the functions of the components included in a conventional BMS. For example, the voltage measuring unit (110), the control unit (120), and the storage unit (130) of the battery diagnostic device (100) may be implemented as components of the BMS.

[0081] In addition, the battery diagnostic device (100) according to the present invention may be provided in a battery pack (10). That is, the battery pack (10) according to the present invention may include the battery diagnostic device (100) described above and one or more battery cells. In addition, the battery pack (10) may further include electrical components (relays, fuses, etc.) and a case, etc.

[0082] FIG. 5 is a diagram illustrating an exemplary configuration of a battery pack (10) according to another embodiment of the present invention. Preferably, the battery pack (10) may include a battery diagnostic device (100).

[0083] The battery pack (10) may include a first battery (Ba), a second battery (Bb), a third battery (Bc), and a fourth battery (Bd). For example, in the embodiment of FIG. 8, the first battery (Ba), the second battery (Bb), the third battery (Bc), and the fourth battery (Bd) may be connected in series. It should be noted that the number of batteries included in the battery pack (10) and the connection relationship of the batteries (series and / or parallel) are not limited by the embodiment of FIG. 8.

[0084] The positive terminal of the first battery (Ba) can be connected to the positive terminal (P+) of the battery pack (10), and the negative terminal of the fourth battery (Bd) can be connected to the negative terminal (P-) of the battery pack (10).

[0085] The voltage measuring unit (110) can be connected to the first sensing line (SL1), the second sensing line (SL2), the third sensing line (SL3), the fourth sensing line (SL4) and the fifth sensing line (SL5).

[0086] Specifically, the voltage measuring unit (110) can be connected to the positive terminal of the first battery (Ba) through the first sensing line (SL1) and to the negative terminal of the first battery (Ba) through the second sensing line (SL2). The voltage measuring unit (110) can measure the voltage of the first battery (Ba) based on the voltage measured at each of the first sensing line (SL1) and the second sensing line (SL2).

[0087] Likewise, the voltage measuring unit (110) can measure the voltage of the second battery (Bb) through the second sensing line (SL2) and the third sensing line (SL3), measure the voltage of the third battery (Bc) through the third sensing line (SL3) and the fourth sensing line (SL4), and measure the voltage of the fourth battery (Bd) through the fourth sensing line (SL4) and the fifth sensing line (SL5).

[0088] An external device may be connected to the positive terminal (P+) and negative terminal (P-) of the battery pack (10). For example, the external device may be a motor of an electric vehicle that receives power from the battery pack (10). As another example, the external device may be a charging device for charging the battery pack (10).

[0090] FIG. 6 is a schematic drawing illustrating a vehicle (600) according to another embodiment of the present invention.

[0091] Referring to FIG. 6, a battery pack (610) according to an embodiment of the present invention may be included in a vehicle (600), such as an electric vehicle (EV) or a hybrid vehicle (HV). The battery pack (610) can drive the vehicle (600) by supplying power to a motor through an inverter provided in the vehicle (600). Additionally, the battery pack (610) may include a battery diagnostic device (100) according to an embodiment of the present invention.

[0093] FIG. 7 is a schematic diagram illustrating a battery diagnostic method according to another embodiment of the present invention.

[0094] Preferably, each step of the battery diagnostic method can be performed by a battery diagnostic device (100). For convenience of explanation, details that overlap with previously described content will be omitted or briefly explained below.

[0095] The voltage measurement step (S100) is a step of measuring the voltage of a plurality of batteries, and can be performed by a voltage measurement unit (110).

[0096] For example, the voltage measuring unit (110) can measure the voltage of each of the multiple batteries.

[0097] In the embodiment of FIG. 2, the voltage measuring unit (110) can measure the voltages of the first battery (Ba), the second battery (Bb), the third battery (Bc), and the fourth battery (Bd) as Va, Vb, Vc, and Vd.

[0098] The voltage deviation calculation step (S200) is a step for calculating the voltage deviation of a plurality of batteries, and can be performed by the control unit (120).

[0099] For example, the control unit (120) can calculate the average voltage of a plurality of batteries. Then, the control unit (120) can calculate the difference between the calculated average voltage and the voltage of each of the plurality of batteries to calculate the voltage deviation of each of the plurality of batteries.

[0100] In the embodiment of FIG. 2, the control unit (120) can calculate the average voltage of the first battery (Ba), the second battery (Bb), the third battery (Bc), and the fourth battery (Bd) as Vavg. The control unit (120) can calculate the difference between the voltage of the first battery (Ba), the second battery (Bb), the third battery (Bc), and the fourth battery (Bd) and the average voltage, and calculate the voltage deviations of the first battery (Ba), the second battery (Bb), the third battery (Bc), and the fourth battery (Bd) as dVa, dVb, dVc, and dVd.

[0101] The voltage deviation change amount calculation step (S300) is a step of calculating the voltage deviation change amount of each of a plurality of batteries based on the voltage deviation calculated in the voltage deviation calculation step (S200), and can be performed by the control unit (120).

[0102] In the embodiment of FIG. 3, the control unit (120) can calculate the second voltage deviation change amount as △dV2 according to the formula "dV2-dV1". The control unit (120) can calculate the third voltage deviation change amount as △dV3 according to the formula "dV3-dV2". The control unit (120) can calculate the fourth voltage deviation change amount as △dV4 according to the formula "dV4-dV3".

[0103] In another embodiment, the control unit (120) can calculate the amount of voltage deviation change for a unit time point by dividing the difference of the calculated voltage deviation by the difference in time points. For example, in the embodiment of FIG. 3, the control unit (120) can calculate the second amount of voltage deviation change for a unit time point by calculating the formula "second voltage deviation change amount (△dV2) ÷ difference in time points (D2-D1)". The control unit (120) can calculate the third amount of voltage deviation change for a unit time point by calculating the formula "third voltage deviation change amount (△dV3) ÷ difference in time points (D3-D2)". The control unit (120) can calculate the fourth amount of voltage deviation change for a unit time point by calculating the formula "fourth voltage deviation change amount (△dV4) ÷ difference in time points (D4-D3)".

[0104] The comparison step (S400) is a step of comparing the voltage deviation change amount of each of the plurality of batteries with a preset reference change amount, and can be performed by the control unit (120).

[0105] For example, in the embodiment of FIG. 3, the control unit (120) can compare each of the second voltage deviation change amount (△dV2), the third voltage deviation change amount (△dV3), and the fourth voltage deviation change amount (△dV4) with a reference change amount.

[0106] The diagnosis step (S500) is a step of diagnosing the state of each of a plurality of batteries according to the comparison result of the comparison step (S400), and can be performed by the control unit (120).

[0107] The control unit (120) may be configured to diagnose the state of a battery in which the voltage deviation change amount is greater than or equal to a reference change amount as an abnormal state. Conversely, the control unit (120) may be configured to diagnose the state of a battery in which the voltage deviation change amount is less than a reference change amount as a normal state.

[0108] For example, in the embodiment of FIG. 4, since the second voltage deviation change amount (△dV2) and the third voltage deviation change amount (△dV3) are smaller than the reference change amount (TH), the control unit (120) can diagnose the state of the battery as normal at time D2 and time D3. Since the fourth voltage deviation change amount (△dV4) is larger than the reference change amount (TH), the control unit (120) can diagnose the state of the battery as abnormal at time D4.

[0109] As another example, the control unit (120) may be configured to calculate the number of times the voltage deviation change amount is greater than or equal to a reference change amount, and to diagnose the state of the battery as abnormal when the calculated number reaches a preset reference number.

[0111] The embodiments of the present invention described above are not limited to implementation through devices and methods, but may also be implemented through a program that realizes a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which such a program is recorded. Such implementation can be easily achieved by a person skilled in the art to which the present invention pertains, based on the description of the embodiments described above.

[0112] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0113] Furthermore, since the present invention described above allows for various substitutions, modifications, and changes within the scope of the technical concept of the present invention to those skilled in the art without departing from the technical spirit of the present invention, it is not limited by the aforementioned embodiments and attached drawings, but rather all or part of each embodiment may be selectively combined to allow for various modifications. Explanation of the symbols

[0114] 10: Battery pack 100: Battery Diagnostic Device 110: Voltage measuring unit 120: Control unit 130: Storage section 600: Car 610: Battery pack

Claims

Claim 1 A battery diagnostic device comprising: a voltage measuring unit configured to measure the voltage of a plurality of batteries; and a control unit configured to calculate the voltage deviation of the plurality of batteries according to the measured voltages, calculate the voltage deviation change amount of each of the plurality of batteries, compare the voltage deviation change amount of each of the plurality of batteries with a preset reference change amount, and diagnose the state of each of the plurality of batteries according to the comparison result, wherein the control unit is configured to calculate the voltage deviation change amount for each of the plurality of batteries by normalizing the difference between the voltage deviation calculated at the current time and the previous voltage deviation calculated at the previous time with respect to the difference between the current time and the previous time. Claim 2 delete Claim 3 delete Claim 4 A battery diagnostic device according to claim 1, wherein the control unit is configured to calculate the difference in voltage deviation by calculating the difference between the voltage deviation and the previous voltage deviation, calculate the difference in time points by calculating the difference between the current time point and the previous time point, and calculate the change in voltage deviation for a unit time point by dividing the difference in voltage deviation by the difference in time points. Claim 5 A battery diagnostic device according to claim 1, wherein the control unit is configured to diagnose the state of a battery in which the voltage deviation change amount is greater than or equal to the reference change amount as an abnormal state, and is configured to diagnose the state of a battery in which the voltage deviation change amount is less than the reference change amount as a normal state. Claim 6 A battery diagnostic device according to claim 5, wherein the control unit is configured to calculate the number of times the voltage deviation change amount is greater than or equal to the reference change amount, and to diagnose the state of the battery as abnormal when the calculated number reaches a preset reference number. Claim 7 A battery diagnostic device according to claim 5, wherein the control unit is configured to diagnose that an internal micro-short circuit has occurred in the battery diagnosed as being in an abnormal state. Claim 8 A battery pack characterized by including a battery diagnostic device according to any one of claims 1 and 4 through 7. Claim 9 An automobile characterized by including a battery diagnostic device according to any one of paragraphs 1 and 4 through 7. Claim 10 A battery diagnosis method comprising: a voltage measurement step for measuring the voltage of a plurality of batteries; a voltage deviation calculation step for calculating the voltage deviation of the plurality of batteries according to the voltages measured in the voltage measurement step; a voltage deviation change amount calculation step for calculating the voltage deviation change amount of each of the plurality of batteries; a comparison step for comparing the voltage deviation change amount of each of the plurality of batteries with a preset reference change amount; and a diagnosis step for diagnosing the state of each of the plurality of batteries according to the comparison result of the comparison step, wherein the voltage deviation change amount calculation step comprises, for each of the plurality of batteries, a step of calculating the voltage deviation change amount by normalizing the difference between the voltage deviation calculated at a current time and the previous voltage deviation calculated at a previous time with respect to the difference between the current time and the previous time.

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