Apparatus and method for diagnosing battery

Abstract

A battery diagnostic device according to one embodiment of the present invention comprises: a voltage measuring unit configured to measure the voltage of each of a plurality of battery cells included in a battery module at each voltage measuring cycle; and a control unit configured to obtain a voltage value for the plurality of battery cells from the voltage measuring unit at each voltage measuring cycle, calculate a voltage change amount between the plurality of voltage values ​​for the plurality of battery cells obtained, calculate a voltage change rate between the calculated voltage change amounts at each diagnostic cycle different from the voltage measuring cycle, and diagnose the battery module based on one or more calculated voltage change rates and a preset reference change rate.

Description

Technology Field

[0001] The present invention relates to a battery diagnostic device and method, and more specifically, to a battery diagnostic device and method for diagnosing the state of a battery module based on the voltage behavior of a plurality of battery cells included in a battery module. Background Technology

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

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

[0004] Conventionally, the condition of a battery was diagnosed by considering the battery's voltage, temperature, and changes in current. In particular, the overvoltage and / or undervoltage of the battery was monitored based on the result of comparing the battery voltage with a reference value.

[0005] However, conventionally, since the battery condition is diagnosed based on the battery voltage at a specific point in time, it is not possible to identify the trend of battery voltage fluctuations, and there were difficulties in diagnosing the battery condition based on such voltage fluctuation trends. (Patent Document) Korean Published Patent Application No. 10-2020-0111014 (20200928) The problem to be solved

[0006] The present invention is devised to solve the above-mentioned problems and aims to provide a battery diagnostic device and method capable of diagnosing the state of a battery module based on the voltage fluctuation trends of a plurality of battery cells.

[0007] 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

[0008] A battery diagnostic device according to one aspect of the present invention may include: a voltage measuring unit configured to measure the voltage of each of a plurality of battery cells included in a battery module at each voltage measuring cycle; and a control unit configured to obtain a voltage value for the plurality of battery cells from the voltage measuring unit at each voltage measuring cycle, calculate a voltage change amount between the plurality of voltage values ​​for the plurality of battery cells obtained, calculate a voltage change rate between the calculated voltage change amounts at each diagnostic cycle different from the voltage measuring cycle, and diagnose the battery module based on one or more voltage change rates calculated up to the current diagnostic cycle and a preset reference change rate.

[0009] The above control unit may be configured to compare the magnitude between the voltage change rate calculated in the current diagnostic cycle and the reference change rate, and to diagnose the battery module according to the comparison result.

[0010] The control unit may be configured to diagnose the battery module based on a reference change rate and the voltage change rate that are preset prior to the current diagnosis cycle when the voltage change rate is greater than or equal to the reference change rate.

[0011] The control unit may be configured to diagnose the battery module as a normal module when the voltage change rate is less than the reference change rate.

[0012] The control unit may be configured to pre-set the largest voltage change rate among one or more voltage change rates calculated prior to the current diagnostic cycle as the reference change rate.

[0013] The control unit may be configured to diagnose the battery module as a defective module when the voltage change rate is greater than or equal to the reference change rate and the reference change rate.

[0014] The control unit may be configured to diagnose the battery module as a normal module when the voltage change rate is greater than or equal to the reference change rate and less than the reference change rate.

[0015] The control unit may be configured to determine the state of the battery module based on at least one of the voltage change rate, the reference change rate, and the reference change rate at each diagnosis cycle, adjust a preset counting value according to the determined state of the battery module, and diagnose the battery module based on the adjusted counting value and the preset reference value.

[0016] The control unit may be configured to diagnose the battery module as the defective module if the adjusted counting value is greater than or equal to the reference value.

[0017] The control unit may be configured to decrease the counting value when the voltage change rate is less than the reference change rate.

[0018] The control unit may be configured to decrease the counting value when the voltage change rate is greater than or equal to the reference change rate and less than the reference change rate.

[0019] The control unit may be configured to increase the counting value when the voltage change rate is greater than or equal to the reference change rate and the reference change rate.

[0020] The above diagnostic cycle can be set to be larger than the above voltage measurement cycle.

[0021] 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.

[0022] A battery diagnostic method according to another aspect of the present invention may include: a voltage measurement step of measuring the voltage of each of a plurality of battery cells included in a battery module at each voltage measurement cycle; a voltage change amount calculation step of calculating the voltage change amount between a plurality of voltage values ​​for the plurality of battery cells at each voltage measurement cycle; a voltage change rate calculation step of calculating the voltage change rate between the calculated plurality of voltage change amounts at each diagnostic cycle different from the voltage measurement cycle; and a battery module diagnostic step of diagnosing the battery module based on one or more voltage change rates calculated up to the current diagnostic cycle and a preset reference change rate. Effects of the invention

[0023] According to one aspect of the present invention, the state of a battery module can be diagnosed based on the voltage behavior of a plurality of battery cells included in the battery module.

[0024] 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

[0025] 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 an exemplary configuration of a battery pack according to another embodiment of the present invention. FIG. 3 is a schematic diagram illustrating a battery diagnostic method according to another embodiment of the present invention. FIG. 4 is a schematic diagram illustrating one embodiment of a battery module diagnosis step among other battery diagnosis methods in another embodiment of the present invention. FIG. 5 is a schematic diagram illustrating another embodiment of the battery module diagnosis step among other battery diagnosis methods in another embodiment of the present invention. Specific details for implementing the invention

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0034] FIG. 1 is a schematic diagram illustrating a battery diagnostic device (100) according to one embodiment of the present invention. FIG. 2 is a schematic diagram illustrating an exemplary configuration of a battery pack (1) according to another embodiment of the present invention.

[0035] Referring to FIG. 1, the battery diagnostic device (100) may include a voltage measuring unit (110) and a control unit (120).

[0036] The voltage measuring unit (110) may be configured to measure the voltage of each of the plurality of battery cells (B) included in the battery module (BM) at each voltage measuring cycle.

[0037] Here, one or more battery cells may be connected in series and / or parallel in the battery module (BM). A battery cell refers to a single independent cell that is physically separable and has a negative terminal and a positive terminal. As an example, a pouch-type lithium polymer cell may be considered as a battery cell.

[0038] Additionally, the voltage measurement period may be a preset period for the voltage measurement unit (110) to measure the voltage of each of the plurality of battery cells (B). For example, the voltage measurement period may be 1 second.

[0039] For example, in the embodiment of FIG. 2, the battery module (BM) may include five battery cells (B1 to B5).

[0040] Additionally, in the embodiment of FIG. 2, the voltage measuring unit (110) may be connected to the first sensing line (SL1), the second sensing line (SL2), the third sensing line (SL3), the fourth sensing line (SL4), the fifth sensing line (SL5), and the sixth sensing line (SL6). The voltage measuring unit (110) may measure the voltage of the first battery cell (B1) through the first sensing line (SL1) and the second sensing line (SL2), and measure the voltage of the second battery cell (B2) through the second sensing line (SL2) and the third sensing line (SL3). Additionally, the voltage measuring unit (110) can measure the voltage of the third battery cell (B3) through the third sensing line (SL3) and the fourth sensing line (SL4), measure the voltage of the fourth battery cell (B4) through the fourth sensing line (SL4) and the fifth sensing line (SL5), and measure the voltage of the fifth battery cell (B5) through the fifth sensing line (SL5) and the sixth sensing line (SL6).

[0041] The control unit (120) may be configured to obtain voltage values ​​for the plurality of battery cells (B) from the voltage measuring unit (110) at each voltage measuring cycle.

[0042] For example, in the embodiment of FIG. 2, the voltage measuring unit (110) and the control unit (120) can be connected to each other so as to be able to communicate. The voltage measuring unit (110) can measure the voltage of a plurality of battery cells (B) at each voltage measurement cycle and transmit the measured voltage value to the control unit (120). Accordingly, the control unit (120) can obtain the voltage value for a plurality of battery cells (B) at each voltage measurement cycle.

[0043] The control unit (120) may be configured to calculate the amount of voltage change between a plurality of voltage values ​​for the plurality of battery cells (B) obtained.

[0044] For example, in the embodiment of FIG. 2, the control unit (120) can calculate the amount of voltage change between the voltage values ​​of the first to fifth battery cells (B1 to B5).

[0045] Specifically, the control unit (120) may be configured to calculate the voltage change amount by calculating the standard deviation or variance between the plurality of voltage values ​​for each voltage measurement cycle. That is, the voltage change amount calculated by the control unit (120) may be the standard deviation or variance of the plurality of voltage values ​​measured at the same point in time.

[0046] The control unit (120) may be configured to calculate the voltage change rate between the calculated multiple voltage change amounts at each diagnostic cycle different from the voltage measurement cycle.

[0047] Here, the diagnostic period is a period in which the voltage change rate is calculated, and may be a period for diagnosing the battery module (BM). Preferably, the diagnostic period may be set to be greater than the voltage measurement period. For example, the diagnostic period may be set to 100 seconds.

[0048] For example, as in the previous embodiment, it is assumed that the voltage measurement period is 1 second and the diagnosis period is 100 seconds. Since the control unit (120) calculates the voltage change amount for a plurality of battery cells (B) for each voltage measurement period, 100 voltage change amounts can be calculated by the control unit (120) whenever the diagnosis period arrives. The control unit (120) can calculate the voltage change rate for the current diagnosis period by calculating the average change rate among the 100 voltage change amounts.

[0049] Specifically, a total of 100 voltage change amounts can be calculated from the n-1st diagnosis cycle to the nth diagnosis cycle. For example, the first to 100th voltage change amounts can be calculated according to the voltage measurement cycle (1 second). The control unit (120) can calculate the voltage change rate for the Nth diagnosis cycle by calculating the average change rate between the first voltage change amount and the 100th voltage change amount using the following mathematical formula 1.

[0050] [Mathematical Formula 1]

[0051] VRn = (Sm - S1)÷m

[0052] Here, VRn is the rate of change of voltage in the n-th diagnostic cycle. m is the number of voltage changes calculated from the n-1-th diagnostic cycle up to the n-th diagnostic cycle. For example, m can be calculated as "diagnostic cycle ÷ voltage measurement cycle". Sm is the last voltage change calculated in the n-th diagnostic cycle, and S1 is the first voltage change calculated in the n-th diagnostic cycle.

[0053] For example, assume that the diagnosis cycle is 100 seconds, the voltage measurement cycle is 1 second, and it is currently the third diagnosis cycle. In the third diagnosis cycle, a total of 100 voltage changes can be calculated. That is, in Equation 1, m can be 100 (the result of calculating "100 ÷ 1"). Sm is the 100th voltage change calculated, and Si can be the first voltage change calculated. According to Equation 1, the voltage change rate (VR3) of the third diagnosis cycle can be calculated according to the formula "(S100 - S1) ÷ 100".

[0054] The control unit (120) may be configured to diagnose the battery module (BM) based on one or more voltage change rates calculated up to the current diagnosis cycle and a preset reference change rate.

[0055] Here, the reference change rate may be a voltage change rate that serves as a reference for diagnosing the battery module (BM) as being in a defective state or a normal state. Preferably, the reference change rate may be set to correspond to a battery module (BM) in the BOL (Beginning of Life) state. Here, a battery module (BM) in the BOL state refers to a battery module (BM) comprising one or more battery cells in the BOL state.

[0056] For example, the control unit (120) may be configured to compare the magnitude between the voltage change rate calculated in the current diagnosis cycle and the reference change rate, and to diagnose the battery module (BM) according to the comparison result.

[0057] A battery diagnostic device (100) according to one embodiment of the present invention can periodically calculate the voltage change rate of a plurality of battery cells (B). That is, the average change rate of the voltage distribution of a plurality of battery cells (B) included in a battery module (BM) can be calculated for each diagnostic cycle. Furthermore, the battery module (BM) can be diagnosed based on the average change rate of the voltage distribution (voltage change rate) and the reference change rate. Accordingly, the battery diagnostic device (100) can diagnose the state of the battery module (BM) more accurately by considering the voltage behavior of a plurality of battery cells (B) during the diagnostic cycle.

[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. At this time, 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.

[0061] For example, the voltage of a plurality of battery cells (B) measured by the voltage measuring unit (110) at each voltage measurement cycle and the voltage change amount calculated by the control unit (120) can be stored in the storage unit (130). Additionally, a reference change rate for a battery module (BM) in a BOL state can also be stored in advance in the storage unit (130). The control unit (120) can access the storage unit (130) to obtain a plurality of voltage change amounts calculated during the diagnosis cycle and obtain a preset reference change rate.

[0063] Below, an example of a control unit (120) diagnosing a battery module (BM) is described.

[0064] First, it is assumed that the voltage measurement period is 1 second, the diagnosis period is 100 seconds, and the current diagnosis period is the 5th diagnosis period. A first voltage change rate can be calculated for the first diagnosis period (1 second to 100 seconds), and a second voltage change rate can be calculated for the second diagnosis period (101 seconds to 200 seconds). Additionally, a third voltage change rate can be calculated for the third diagnosis period (201 seconds to 300 seconds), a fourth voltage change rate can be calculated for the fourth diagnosis period (301 seconds to 400 seconds), and a fifth voltage change rate can be calculated for the fifth diagnosis period (401 seconds to 500 seconds).

[0065] The control unit (120) may be configured to compare the magnitude between the voltage change rate calculated in the current diagnosis cycle and the reference change rate, and to diagnose the battery module (BM) according to the comparison result.

[0066] Specifically, if the voltage change rate is less than the reference change rate, the control unit (120) may be configured to diagnose the battery module (BM) as a normal module.

[0067] For example, if the fifth voltage change rate calculated in the current diagnosis cycle is less than the reference change rate, the control unit (120) can diagnose the battery module (BM) as a normal module.

[0068] That is, if the voltage change rate of a plurality of battery cells (B) calculated in the current diagnosis cycle is less than the reference change rate, the control unit (120) can diagnose the battery module (BM) to be in a normal state without comparing the voltage change rate of the current diagnosis cycle with the voltage change rate of the previous diagnosis cycle.

[0069] Conversely, if the voltage change rate is greater than or equal to the reference change rate, the control unit (120) may be configured to diagnose the battery module (BM) based on the voltage change rate and the reference change rate preset in the previous diagnosis cycle.

[0070] Here, the control unit (120) may be configured to pre-set the largest voltage change rate among one or more voltage change rates calculated in the previous diagnostic cycle as the reference change rate.

[0071] For example, it is assumed that the third voltage change rate among the first to fourth voltage change rates is the largest. The control unit (120) can pre-set the third voltage change rate, which is the largest among the first to fourth voltage change rates, as a reference change rate prior to the fifth diagnostic cycle.

[0072] The control unit (120) may be configured to diagnose the battery module (BM) as the normal module when the voltage change rate is greater than or equal to the reference change rate and less than the reference change rate.

[0073] For example, if the fifth voltage change rate is greater than or equal to the reference change rate but less than the reference change rate (third voltage change rate), the control unit (120) can diagnose the battery module (BM) as a normal module in the fifth diagnosis cycle. That is, if the fifth voltage change rate of a plurality of battery cells (B) in the fifth diagnosis cycle is greater than or equal to the reference change rate but less than the reference change rate (third voltage change rate), the control unit (120) can determine that the rate of change for the voltage deviation of a plurality of battery cells (B) has not increased compared to the previous diagnosis cycle. Therefore, if the voltage change rate of the current cycle is greater than or equal to the reference change rate but less than the reference change rate, the control unit (120) can diagnose the battery module (BM) as a normal module.

[0074] Conversely, the control unit (120) may be configured to diagnose the battery module (BM) as a defective module when the voltage change rate is greater than or equal to the reference change rate and the reference change rate.

[0075] For example, if the voltage change rate (5th voltage change rate) of the current diagnostic cycle (5th diagnostic cycle) is greater than or equal to the reference change rate and the reference change rate (3rd voltage change rate), the control unit (120) can determine that the rate of change for the voltage deviation of a plurality of battery cells (B) is greater than or equal to the reference change rate and is increasing compared to the previous diagnostic cycle. That is, the control unit (120) can determine that the degree of degradation among the plurality of battery cells (B) included in the battery module (BM) of the current cycle is uneven. Accordingly, the control unit (120) can diagnose the battery module (BM) as a defective module.

[0076] In summary, the battery diagnostic device (100) can diagnose the battery module (BM) as a normal module without considering the reference change rate if the voltage change rate is less than the reference change rate. Additionally, the battery diagnostic device (100) can diagnose the battery module (BM) as a normal module if the voltage change rate is greater than or equal to the reference change rate and less than the reference change rate. Finally, the battery diagnostic device (100) can diagnose the battery module (BM) as a defective module if the voltage change rate is greater than or equal to both the reference change rate and the reference change rate.

[0077] That is, the battery diagnostic device (100) can consider the voltage change rate, reference change rate, and reference change rate of the current diagnostic cycle during the process of diagnosing the state of the battery module (BM). By comparing the voltage change rate and the reference change rate, the state of the current battery module (BM) can be diagnosed in relation to the battery module (BM) in the BOL state. Additionally, by comparing the voltage change rate and the reference change rate, the state of the battery module (BM) regarding the non-uniform degradation of multiple battery cells (B) can be diagnosed. Therefore, the battery diagnostic device (100) has the advantage of being able to diagnose the state of the battery module (BM) in the current diagnostic cycle from a more diverse perspective.

[0079] Meanwhile, the control unit (120) may be configured to set the largest voltage change rate among one or more voltage change rates calculated prior to the current diagnosis cycle as the reference change rate.

[0080] For example, as in the preceding embodiment, it is assumed that the control unit (120) has calculated the first to fifth voltage change rates, and that the fifth voltage change rate was calculated most recently. The control unit (120) may set the voltage change rate with the largest magnitude among the first to fourth voltage change rates, excluding the fifth voltage change rate, as the reference change rate. Hereinafter, it is assumed that the first voltage change rate is set as the reference change rate.

[0081] The control unit (120) can be configured to compare the magnitude between the reference change rate and the voltage change rate, and to diagnose the battery module (BM) based on the comparison result.

[0082] Specifically, if the voltage change rate is greater than or equal to the reference change rate, the control unit (120) may be configured to diagnose the battery module (BM) as a defective module. For example, if the fifth voltage change rate set as the voltage change rate is greater than or equal to the first voltage change rate set as the reference change rate, the state of the battery module (BM) may be diagnosed as a defective module.

[0083] Conversely, if the voltage change rate is less than the reference change rate, the control unit (120) may be configured to diagnose the battery module (BM) as a normal module. For example, if the fifth voltage change rate set as the voltage change rate is less than the first voltage change rate set as the reference change rate, the state of the battery module (BM) may be diagnosed as a normal module.

[0084] In one embodiment of the present invention, the control unit (120) can diagnose the battery module (BM) as a defective module when the voltage change rate of the battery module (BM) increases. Here, the case where the voltage change rate increases may be a case where the amount of voltage change (standard deviation or variance) for a plurality of battery cells (B) increases. For example, the voltage change rate of the battery module (BM) may increase when the voltage deviation for a plurality of battery cells (B) increases due to non-uniform degradation of a plurality of battery cells (B). Accordingly, the battery management device can diagnose the battery module (BM) based on the result of comparing the voltage change rate with the reference change rate.

[0086] Meanwhile, the control unit (120) may be configured to diagnose each of the plurality of battery cells (B) based on a voltage value corresponding to each of the plurality of battery cells (B) at each voltage measurement cycle, in parallel with diagnosing the battery module (BM).

[0087] Specifically, upper and lower voltage limits for the voltage of the battery cell may be pre-set. The control unit (120) can diagnose a battery cell in an overvoltage state if the voltage value received from the voltage measuring unit (110) is greater than or equal to the upper voltage limit. Additionally, the control unit (120) can diagnose a battery cell in a low voltage state if the received voltage value is less than or equal to the lower voltage limit. The control unit (120) can diagnose a battery cell in a normal state if the voltage value is less than the upper voltage limit and exceeds the lower voltage limit.

[0088] That is, the control unit (120) can diagnose the state of the battery module (BM) at each diagnosis cycle, and can also diagnose the state of each of the multiple battery cells (B) at each voltage measurement cycle.

[0089] Therefore, there is an advantage in that the state of each of the multiple battery cells (B) and the state of the battery module (BM) can all be diagnosed by the battery management device.

[0091] Hereinafter, an embodiment is described in which a control unit (120) adjusts a counting value and diagnoses a battery module (BM) according to the adjusted counting value.

[0092] The control unit (120) may be configured to determine the state of the battery module (BM) based on at least one of the voltage change rate, the reference change rate, and the reference change rate at each diagnostic cycle, and to adjust a preset counting value according to the determined state of the battery module (BM).

[0093] Here, the counting value can be set to an initial value and a minimum value of 0. Also, the counting value can be adjusted by increasing or decreasing by 1 by the control unit (120).

[0094] Specifically, if the battery module (BM) is diagnosed as a defective module by the control unit (120), the use of the battery module (BM) may be stopped and a replacement may be requested. That is, unlike when the battery module (BM) is diagnosed as a normal module, there may be a penalty for the battery module (BM) when it is diagnosed as a defective module. Therefore, the control unit (120) may be configured to conservatively diagnose the battery module (BM) as a defective state according to stricter criteria.

[0095] For example, the control unit (120) may be configured to decrease the counting value when the voltage change rate is less than the reference change rate. In this case, the control unit (120) may diagnose the battery module (BM) as a normal module. If the existing counting value is 0, the counting value can be maintained at 0 because the counting value can no longer be decreased (since the minimum value is set to 0).

[0096] Additionally, the control unit (120) may be configured to decrease the counting value when the voltage change rate is greater than or equal to the reference change rate and less than the reference change rate. In this case, the control unit (120) can diagnose the battery module (BM) as a normal module.

[0097] Additionally, the control unit (120) may be configured to increase the counting value when the voltage change rate is greater than or equal to the reference change rate and the reference change rate. In this case, the control unit (120) may be configured not to immediately diagnose the battery module (BM) as a defective module, but to diagnose the battery module (BM) based on the adjusted counting value and the preset reference value.

[0098] Here, the reference value is a preset value and can be set as a natural number.

[0099] Specifically, the control unit (120) may be configured to diagnose the battery module (BM) as the defective module if the adjusted counting value is greater than or equal to the reference value.

[0100] For example, if the voltage change rate is greater than the reference change rate and reference change rate, the counting value may be increased. And, if the adjusted counting value is greater than the reference value, the battery module (BM) may be diagnosed as a defective module. That is, the control unit (120) may be configured to diagnose the battery module (BM) as a defective module when the voltage change rate exceeds the reference change rate and reference change rate and exceeds the reference value. Therefore, since the control unit (120) diagnoses the battery module (BM) as a defective module through strict criteria, the possibility of misdiagnosing a normal module as a defective module can be significantly reduced.

[0101] However, if the voltage change rate is less than the reference change rate, or if the voltage change rate is greater than or equal to the reference change rate but less than the reference change rate, the control unit (120) may reduce the counting value. That is, in such cases, the adjusted counting value must be less than the reference value. Therefore, in order to use system resources more efficiently and prevent unnecessary waste of system resources, the control unit (120) can diagnose the battery module (BM) as a normal module without comparing the adjusted counting value with the reference value.

[0102] A battery diagnostic device (100) according to one embodiment of the present invention can diagnose a battery module (BM) as a defective module through strict criteria based on a counting value and a reference value. Accordingly, the battery management device can prevent a normal module from being misdiagnosed as a defective module.

[0104] 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.

[0105] In addition, the battery diagnostic device (100) according to the present invention may be provided in a battery pack (1). For example, referring to FIG. 2, the battery pack (1) according to the present invention may include a battery diagnostic device (100) and a battery module (BM). In addition, the battery pack (1) may further include electrical components (relays, fuses, etc.) and a case, etc.

[0107] FIG. 3 is a schematic diagram illustrating a battery diagnostic method according to another embodiment of the present invention.

[0108] Preferably, each step of the battery diagnostic method can be performed by a battery management device. Below, content that overlaps with what has been previously explained is omitted or briefly described.

[0109] Referring to FIG. 3, the battery diagnostic method may include a voltage measurement step (S100), a voltage change amount calculation step (S200), a voltage change rate calculation step (S300), and a battery module diagnostic step (S400).

[0110] The voltage measurement step (S100) is a step of measuring the voltage of each of the plurality of battery cells (B) included in the battery module (BM) at each voltage measurement cycle, and can be performed by the voltage measurement unit (110).

[0111] The voltage change amount calculation step (S200) is a step of calculating the voltage change amount between a plurality of voltage values ​​for the plurality of battery cells (B) for each voltage measurement cycle, and can be performed by the control unit (120).

[0112] The control unit (120) receives a plurality of voltage values ​​for a plurality of battery cells (B) from the voltage measuring unit (110) and can calculate the amount of voltage change between the received plurality of voltage values.

[0113] For example, the control unit (120) can calculate the amount of voltage change by calculating the variance or standard deviation between multiple voltage values.

[0114] The voltage change rate calculation step (S300) is a step of calculating the voltage change rate between a plurality of calculated voltage change amounts at each diagnostic cycle different from the voltage measurement cycle, and can be performed by the control unit (120).

[0115] It is assumed that the voltage measurement cycle is 1 second and the diagnosis cycle is 100 seconds. The control unit (120) can calculate the voltage change amount of multiple voltage values ​​for multiple battery cells (B) measured every 1 second. In addition, the control unit (120) can calculate the voltage change rate for multiple voltage change amounts every 100 seconds. In this case, the control unit (120) can calculate the voltage change rate for 100 voltage change amounts every 100 seconds.

[0116] For example, the control unit (120) can calculate the voltage change rate for the corresponding diagnostic cycle by calculating the average change rate between the first voltage change amount and the last voltage change amount calculated in the corresponding diagnostic cycle.

[0117] The battery module diagnosis step (S400) is a step of diagnosing the battery module (BM) based on one or more voltage change rates calculated up to the current diagnosis cycle and a preset reference change rate, and can be performed by the control unit (120).

[0119] FIG. 4 is a schematic diagram illustrating one embodiment of a battery module diagnosis step (S400) among other battery diagnosis methods in another embodiment of the present invention.

[0120] Referring to FIG. 4, the battery module diagnostic step (S400) may include steps S410 to S440.

[0121] In step S410, the voltage change rate and the reference change rate may be compared. Specifically, the magnitude between the voltage change rate calculated in the current diagnostic cycle and the reference change rate may be compared. If the voltage change rate is greater than or equal to the reference change rate, step S420 is performed, and if the voltage change rate is less than the reference change rate, step S440 may be performed.

[0122] In step S420, the voltage change rate and the reference change rate may be compared. Specifically, the magnitude between the voltage change rate calculated in the current diagnostic cycle and the reference change rate pre-set prior to the current diagnostic cycle may be compared. That is, the magnitude between the voltage change rate calculated in the current diagnostic cycle and the reference change rate with the largest magnitude among one or more voltage change rates calculated in the previous diagnostic cycle may be compared. If the voltage change rate is greater than or equal to the reference change rate, step S430 is performed, and if the voltage change rate is less than the reference change rate, step S440 may be performed.

[0123] In step S430, the battery module (BM) can be diagnosed as a defective module. That is, if the voltage change rate is greater than or equal to the reference change rate and the reference change rate, the control unit (120) can diagnose the battery module (BM) as a defective module.

[0124] In step S440, the battery module (BM) can be diagnosed as a normal module. That is, if the voltage change rate is less than the reference change rate, or if the voltage change rate is greater than or equal to the reference change rate but less than the reference change rate, the control unit (120) can diagnose the battery module (BM) as a normal module.

[0126] FIG. 5 is a schematic diagram illustrating another embodiment of the battery module diagnosis step (S400) among other battery diagnosis methods in another embodiment of the present invention.

[0127] Referring to FIG. 5, the battery module diagnostic step (S400) may include steps S410 to S470. Below, the embodiment of FIG. 5 will be described focusing on the differences from the embodiment of FIG. 4.

[0128] In step S410, if the voltage change rate is greater than or equal to the reference change rate, step S420 is performed, and if the voltage change rate is less than the reference change rate, step S460 may be performed.

[0129] In step S420, if the voltage change rate is greater than or equal to the reference change rate, step S450 is performed, and if the voltage change rate is less than the reference change rate, step S460 may be performed.

[0130] In step S450, the counting value may be increased. For example, the counting value may be set to an initial value and a minimum value of 0, and increased by 1. That is, if the voltage change rate is greater than or equal to the reference change rate and the reference change rate, the control unit (120) may increase the counting value. After the counting value is increased, step S470 may be performed.

[0131] In step S470, the counting value and the reference value may be compared. Specifically, if the counting value increased in step S450 is greater than or equal to the reference value, step S430 may be performed. Conversely, if the counting value increased in step S450 is less than the reference value, step S440 may be performed.

[0132] In step S460, the counting value may be reduced. That is, if the voltage change rate is less than the reference change rate, or if the voltage change rate is greater than or equal to the reference change rate but less than the reference change rate, the control unit (120) may reduce the counting value. However, the counting value may not be reduced to a value less than the set minimum value. After step S460, step S440 is performed so that the battery module (BM) can be diagnosed as a normal module.

[0134] 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.

[0135] 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.

[0136] 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

[0137] 1: Battery pack 100: Battery Diagnostic Device 110: Voltage measuring unit 120: Control unit 130: Storage section BM: Battery Module C: Multiple battery cells

Claims

Claim 1 A battery diagnostic device comprising: a voltage measuring unit configured to measure the voltage of each of a plurality of battery cells included in a battery module at each voltage measuring cycle; and a control unit that obtains a plurality of voltage values ​​representing the voltage of each of the plurality of battery cells from the voltage measuring unit at each voltage measuring cycle and calculates a voltage change amount representing a voltage deviation between the plurality of voltage values, wherein the control unit is configured to calculate the voltage change rate between the plurality of voltage change amounts calculated when the voltage measuring cycle proceeds multiple times at each diagnostic cycle different from the voltage measuring cycle, and to diagnose the battery module based on one or more voltage change rates calculated up to the current diagnostic cycle and a preset reference change rate. Claim 2 A battery diagnostic device according to claim 1, wherein the control unit is configured to compare the magnitude between the voltage change rate calculated in the current diagnostic cycle and the reference change rate, and to diagnose the battery module according to the comparison result. Claim 3 A battery diagnostic device according to claim 2, wherein the control unit is configured to diagnose the battery module based on a reference change rate and the voltage change rate preset in a previous diagnostic cycle when the voltage change rate calculated in the current diagnostic cycle is greater than or equal to the reference change rate, and to diagnose the battery module as a normal module when the voltage change rate calculated in the current diagnostic cycle is less than the reference change rate. Claim 4 A battery diagnostic device according to paragraph 3, wherein the control unit is configured to pre-set the largest voltage change rate among one or more voltage change rates calculated in the previous diagnostic cycle as the reference change rate. Claim 5 A battery diagnostic device according to claim 3, wherein the control unit is configured to diagnose the battery module as a defective module when the voltage change rate calculated in the current diagnostic cycle is greater than or equal to the reference change rate and the reference change rate, and to diagnose the battery module as a normal module when the voltage change rate calculated in the current diagnostic cycle is greater than or equal to the reference change rate and less than the reference change rate. Claim 6 A battery diagnostic device according to claim 5, wherein the control unit is configured to determine the state of the battery module based on at least one of the voltage change rate calculated in the current diagnostic cycle, the reference change rate, and the reference change rate for each diagnostic cycle, adjust a preset counting value according to the determined state of the battery module, and diagnose the battery module based on the adjusted counting value and the preset reference value. Claim 7 A battery diagnostic device according to claim 6, wherein the control unit is configured to diagnose the battery module as the defective module if the adjusted counting value is greater than or equal to the reference value. Claim 8 A battery diagnostic device according to claim 6, wherein the control unit is configured to decrease the counting value when the voltage change rate calculated in the current diagnostic cycle is less than the reference change rate, decrease the counting value when the voltage change rate calculated in the current diagnostic cycle is greater than or equal to the reference change rate and less than the reference change rate, and increase the counting value when the voltage change rate calculated in the current diagnostic cycle is greater than or equal to the reference change rate and the reference change rate. Claim 9 A battery diagnostic device according to claim 1, wherein the control unit is configured to calculate the voltage change amount by calculating the standard deviation or variance between the plurality of voltage values ​​for each voltage measurement cycle. Claim 10 A battery diagnostic device according to claim 1, characterized in that the diagnostic cycle is set to be greater than the voltage measurement cycle. Claim 11 A battery diagnostic device according to claim 1, wherein the control unit is configured to diagnose each of the plurality of battery cells based on a voltage value corresponding to each of the plurality of battery cells at each of the voltage measurement cycles. Claim 12 A battery pack characterized by including a battery diagnostic device according to any one of claims 1 to 11. Claim 13 A battery diagnostic method comprising: a voltage measurement step in which a battery diagnostic device measures the voltage of each of a plurality of battery cells included in a battery module at each voltage measurement cycle; a voltage change amount calculation step in which the battery diagnostic device calculates a voltage change amount representing a voltage deviation between a plurality of voltage values ​​representing the voltage of each of the plurality of battery cells at each voltage measurement cycle; a voltage change rate calculation step in which the battery diagnostic device calculates a voltage change rate between a plurality of voltage change amounts calculated by proceeding with the voltage measurement cycle multiple times at each diagnostic cycle different from the voltage measurement cycle; and a battery module diagnostic step in which the battery diagnostic device diagnoses the battery module based on one or more voltage change rates calculated up to the current diagnostic cycle and a preset reference change rate.

Images