Battery diagnostic device and its operating method

Abstract

A battery diagnostic device according to one embodiment disclosed in this document includes: an information acquisition unit that measures the current and voltage of each of a plurality of battery cells; a resistance measurement unit that measures the cell resistance of each of the plurality of battery cells based on the discharge current and discharge voltage of each of the plurality of battery cells; and a controller that, prior to the resistance measurement by the resistance measurement unit, applies a predetermined charging current to each of the plurality of battery cells for a predetermined charging time and determines the assembly state of each of the plurality of battery cells based on the cell resistance.

Description

TECHNICAL FIELD

[0001] The present invention claims the benefit of priority based on Korean Patent Application No. 10-2023-0133745 filed on October 6, 2023, and all contents disclosed in the documents of the said Korean patent application are incorporated as part of the present specification.

[0002] The embodiments disclosed in this document relate to a battery diagnostic apparatus and an operating method thereof. BACKGROUND ART

[0003] In recent years, the demand for portable electronic products such as notebook computers, video cameras, and mobile phones has increased rapidly, and the development of electric vehicles, rechargeable batteries for energy storage, robots, satellites and the like has been fully underway. Along with this, research on high-performance secondary batteries capable of repeated charging and discharging is actively progressing.

[0004] Examples of secondary batteries currently commercialized include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Among them, lithium secondary batteries have the advantages of almost no memory effect, free charging and discharging, extremely low self-discharge rate, and high energy density compared with nickel-based secondary batteries, and thus are attracting attention.

[0005] On the other hand, among such secondary batteries, lithium iron phosphate (LFP) batteries experience an increase in resistance due to self-discharge during the storage period after cell production. That is, if a long period of time elapses after cell production before pack assembly, the SOC (State of Charge) decreases due to self-discharge of the cells, leading to an increase in cell resistance. The assembly state of a plurality of battery cells included in a battery pack is determined by measuring the resistance of each cell. However, since the increase in resistance due to self-discharge and the increase in resistance due to assembly failure cannot be distinguished, this has led to results in which the accuracy of assembly failure determination is reduced and efficiency is lowered. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] One objective of the embodiments disclosed in this document is to provide a battery diagnostic device capable of determining the assembly state of a battery cell, and a method for operating the same.

[0007] One objective of the embodiments disclosed herein is to provide a battery diagnostic device and a method for operating the same that improve the accuracy of determining the assembly state of a battery cell by compensating for the increase in the resistance of the battery cell.

[0008] The technical problems of the embodiments described herein are not limited to those mentioned above, and other technical problems not mentioned can be clearly understood by a person ordinary in the art to which the present invention pertains from the following description. [Means for solving the problem]

[0009] A battery diagnostic device according to one embodiment disclosed herein includes: an information acquisition unit configured to measure the current and voltage of each of a plurality of battery cells; a resistance measurement unit configured to measure the cell resistance of each of the plurality of battery cells based on the discharge current and discharge voltage of each of the plurality of battery cells; and a controller configured to apply a predetermined charging current to each of the plurality of battery cells for a predetermined charging time, prior to the resistance measurement by the resistance measurement unit, and to determine the assembly state of each of the plurality of battery cells based on the cell resistance.

[0010] According to one embodiment, the information acquisition unit may be further configured to acquire the manufacturing date of each of the plurality of battery cells, and the controller may be further configured to determine whether the manufacturing date of each of the plurality of battery cells is earlier than the reference date, and to select a compensation battery cell from the plurality of battery cells based on the determination result.

[0011] According to one embodiment, the controller can apply the charging current to the compensating battery cell.

[0012] According to one embodiment, the information acquisition unit acquires the State of Charge (SOC) of each of the plurality of battery cells, the controller determines whether the SOC of each of the plurality of battery cells is less than a reference SOC, and based on the determination result, can be further configured to select a compensation battery cell from the plurality of battery cells.

[0013] According to one embodiment, the controller may be further configured to adjust the magnitude of the charging current to be greater than twice the magnitude of the discharge current.

[0014] According to one embodiment, the controller may be further configured to maintain the current of each of the plurality of battery cells within a predetermined range between the charging time and the resistance measurement of the resistance measuring unit.

[0015] According to one embodiment, the resistance measuring unit is further configured to discharge each of the plurality of battery cells during a predetermined discharge time and measure the cell resistance of each of the plurality of battery cells, and the controller may be further configured to adjust the predetermined charging time to be longer than the predetermined discharge time.

[0016] According to one embodiment, the resistance measuring unit can be further configured to measure the cell resistance of each of the plurality of battery cells using the DCIR (Direct Current Internal Resistance) method.

[0017] According to one embodiment, the controller can be further configured to determine that the assembly state of a battery cell among the plurality of battery cells is defective if its cell resistance is greater than or equal to a previously set resistance.

[0018] A battery diagnostic method according to one embodiment disclosed herein includes the steps of: applying a predetermined charging current to each of a plurality of battery cells for a predetermined charging time; measuring the cell resistance of each of the plurality of battery cells based on the discharge current and discharge voltage of each of the plurality of battery cells; and determining the assembly state of each of the plurality of battery cells based on the cell resistance.

[0019] According to one embodiment, the method may further include the steps of obtaining the manufacturing date or SOC (State of Charge) of each of the plurality of battery cells, and selecting a compensation battery cell from the plurality of battery cells based on at least one of the manufacturing date or SOC.

[0020] According to one embodiment, the magnitude of the charging current can be twice or more the magnitude of the discharge current.

[0021] According to one embodiment, the step of measuring the cell resistance is to discharge each of the plurality of battery cells during a predetermined discharge time and measure the cell resistance of each of the plurality of battery cells, wherein the predetermined charging time can be longer than the predetermined discharge time.

[0022] According to one embodiment, the step of measuring the cell resistance can be the step of measuring the cell resistance of each of the plurality of battery cells using the DCIR (Direct Current Internal Resistance) method.

[0023] According to one embodiment, in the step of determining the assembly state, among the plurality of battery cells, the assembly state of a battery cell whose cell resistance is greater than or equal to a previously set resistance can be determined to be defective.

[0024] Specific details of other embodiments are included in the detailed description and drawings. [Effects of the Invention]

[0025] The battery diagnostic apparatus and the operation method thereof according to the embodiments disclosed in this document are capable of determining the assembled state of a battery cell.

[0026] The battery diagnostic apparatus and the operation method thereof according to the embodiments disclosed in this document can compensate for an increase in the resistance of a battery cell, and improve the accuracy of determining the assembled state of the battery cell.

[0027] The effects of the battery diagnostic apparatus and the operation method thereof according to the disclosure of this document are not limited to the effects mentioned above, and still other effects not mentioned can be clearly understood by those skilled in the art from the disclosure of this document. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] [Figure 1] This is a block diagram showing a battery pack according to an embodiment disclosed in this document. [Figure 2] This is a block diagram showing a battery diagnostic apparatus according to an embodiment disclosed in this document. [Figure 3] This is a diagram illustrating the operation of the battery diagnostic apparatus according to an embodiment disclosed in this document to compensate for an increase in the resistance of a battery cell. [Figure 4] This is a flowchart showing a battery diagnostic method according to an embodiment disclosed in this document. [Figure 5] This is a block diagram showing a computing system that executes a battery diagnostic method according to an embodiment disclosed in this document. In connection with the description of the drawings, the same or similar reference numerals are used for the same or similar components. DETAILED DESCRIPTION OF EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0029] Embodiments of the present invention are described below with reference to the accompanying drawings. However, it should be understood that this does not limit the present invention to any particular embodiment, but rather includes various modifications, equivalents, and / or alternatives to the embodiments of the present invention.

[0030] The embodiments and terminology used in this document should be understood to include a variety of modifications, equivalents, or substitutions of the embodiments, rather than limiting the technical features described herein to any particular embodiment. In relation to the description of the drawings, similar or related components are referred to by similar reference numerals. The singular form of a noun corresponding to an item may include one or more such items unless the context clearly indicates otherwise.

[0031] In this document, each of the phrases “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and “at least one of A, B, or C” may include any one of the items listed with the phrase in question, or any possible combination thereof. Terms such as “first,” “second,” “first,” “second,” “A,” “B,” “(a),” or “(b)” are used solely to distinguish one component from other components and, unless otherwise stated, do not limit the component in any other way (e.g., weight or order).

[0032] Wherever a component (e.g., the first) is referred to as being "connected," "coupled," or "connected" to another component (e.g., the second), with or without the terms "operatably" or "communicatively," or where it is referred to as "coupled" or "connected," it means that the first component may be connected to the other component directly (e.g., by wire or wirelessly) or indirectly (e.g., via the third component).

[0033] The methods according to the various embodiments disclosed herein may be provided in a computer program product. A computer program product may be traded as a commodity between a seller and a buyer. A computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read-only memory, CD-ROM) or online (e.g., download or upload) via an application store or directly between two user devices. In the case of online distribution, at least a portion of the computer program product may be temporarily stored or generated on an ad-hoc basis in a device-readable storage medium such as the memory of a manufacturer's server, an application store server, or an intermediary server.

[0034] According to the embodiments disclosed herein, each of the aforementioned components (e.g., a module or a program) may include one or more individuals, and some of the individuals may be separated and arranged in other components. According to the embodiments disclosed herein, one or more of the aforementioned components or operations may be omitted, or one or more other components or operations may be added. Alternatively or additionally, multiple components (e.g., a module or a program) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the multiple components in the same or similar manner as those performed by the components of the multiple components before the integration. According to the embodiments disclosed herein, operations performed by a module, program, or other component may be performed sequentially, in parallel, repeatedly, or heuristically, or one or more of the operations may be performed in a different order, omitted, or one or more other operations may be added.

[0035] Figure 1 is a block diagram showing a battery pack according to one embodiment disclosed in this document.

[0036] Referring to Figure 1, a battery control system is schematically shown, which includes a battery pack 1 according to one embodiment disclosed in this document and a higher-level controller 2 included in the high-level controller system.

[0037] As shown in Figure 1, the battery pack 1 may include one or more battery cells 11, a switching unit 14 connected in series to the first terminal and / or second terminal of the battery cell 11 for controlling the flow of charging or discharging current to the battery cell 11, and a battery management system 20 that monitors the voltage, current, temperature, etc. of the battery pack 1 and manages to prevent overcharging and over-discharging.

[0038] In this case, the battery pack 1 can be equipped with multiple battery cells 11, sensors 12, switching units 14, and battery management systems 20. For example, the first terminal can be the (+) terminal of the battery cell 11, and the second terminal can be the (-) terminal.

[0039] Here, the switching unit 14 is an element for controlling the flow of current related to the charging or discharging of the multiple battery cells 11, and depending on the specifications of the battery pack 1, at least one relay, magnetic contactor, etc. can be used.

[0040] The battery management system 20 is an interface that receives input values ​​of the various parameters described above, and may include multiple terminals and circuits connected to these terminals that process the input values. The battery management system 20 can also control the on / off state of the switching unit 14, such as a relay or contactor, and can be connected to the battery cell 11 to monitor the state of each battery cell 11.

[0041] The high-level controller 2 can transmit control signals related to the battery cell 11 to the battery management system 20. This allows the battery management system 20 to be controlled based on the signals applied from the high-level controller 2.

[0042] According to one embodiment, the battery management system 20 may include the battery diagnostic device 100 shown in Figure 2. According to another embodiment, the battery management system 20 may be a different system from the battery diagnostic device 100 shown in Figure 2. That is, the battery diagnostic device 100 shown in Figure 2 may be included in the battery pack 1, or it may be configured as a different device outside the battery pack 1.

[0043] In the following explanation, for the sake of clarity, it is assumed that the battery diagnostic device 100 is configured as another device outside of the battery pack 1, but it is not limited to this configuration. For example, the operation of the battery diagnostic device 100 described below can be performed by a battery management system (BMS) within the vehicle, as well as by a variety of other devices such as servers, clouds, chargers, or chargers / dischargers.

[0044] Figure 2 is a block diagram showing a battery diagnostic device according to one embodiment disclosed in this document.

[0045] Referring to Figure 2, the battery diagnostic device 100 may include an information acquisition unit 110, a resistance measurement unit 120, and a controller 130. The battery diagnostic device 100 can determine the assembly state of the battery cells using the information acquisition unit 110, the resistance measurement unit 120, and the controller 130. That is, the battery diagnostic device 100 can diagnose the state in which each of the multiple battery cells 11 contained in the battery pack is assembled in the battery pack.

[0046] The information acquisition unit 110 can acquire information about the battery cells. The information acquisition unit 110 can acquire information about each of the multiple battery cells 11 included in the battery pack. According to the embodiment, the information acquisition unit 110 can acquire information about the current and voltage of each of the multiple battery cells 11. The information acquisition unit 110 can measure the current or voltage of each of the multiple battery cells 11, but is not limited to this. For example, the information acquisition unit 110 may not measure the voltage or current, but instead receive information such as the voltage or current of each of the multiple battery cells 11 from another device or server.

[0047] According to the embodiment, the information acquisition unit 110 can acquire manufacturing date information. That is, the information acquisition unit 110 can acquire the manufacturing date information for each of the multiple battery cells 11. For example, the information acquisition unit 110 can acquire manufacturing date information by receiving the manufacturing date information corresponding to each of the multiple battery cells 11 from another storage unit or server.

[0048] According to the embodiment, the information acquisition unit 110 can acquire State of Charge (SOC) information. That is, the information acquisition unit 110 can acquire the SOC information for each of the multiple battery cells 11. For example, the information acquisition unit 110 can acquire SOC information by directly measuring the SOC of each of the multiple battery cells 11, or by receiving the SOC information corresponding to each of the multiple battery cells 11 from another storage unit or server.

[0049] The resistance measuring unit 120 can measure the cell resistance of a battery cell. The resistance measuring unit 120 can measure the cell resistance of each of the multiple battery cells 11 included in the battery pack.

[0050] According to the embodiment, the resistance measurement unit 120 can measure cell resistance using the DCIR (Direct Current Internal Resistance) method. In this case, the resistance measurement unit 120 can measure the voltage drop by discharging each of the multiple battery cells 11 with a predetermined discharge current, and measure the cell resistance of each of the multiple battery cells 11 based on the discharge current value and the voltage drop value. That is, the resistance measurement unit 120 can measure the cell resistance of each of the multiple battery cells 11 by discharging each of the multiple battery cells 11 during the discharge time based on the discharge current and discharge voltage.

[0051] The controller 130 can apply a charging current to the battery cells. The controller 130 can either directly apply a charging current to each of the multiple battery cells 11, or control a separately provided charger or the like to apply a charging current to each of the multiple battery cells 11.

[0052] According to this embodiment, the controller 130 can apply a charging current before the resistance measuring unit 120 measures the cell resistance. That is, after the controller 130 applies a charging current to each of the multiple battery cells 11, the resistance measuring unit 120 can measure the cell resistance of each of the multiple battery cells 11. In other words, the application of the charging current by the controller 130 and the measurement of the cell resistance by the resistance measuring unit 120 constitute a single set, and the measurement of the cell resistance by the resistance measuring unit 120 can be performed after the application of the charging current by the controller 130.

[0053] The controller 130 can adjust the magnitude of the charging current. According to the embodiment, the controller 130 can adjust the magnitude of the charging current to be greater than twice the magnitude of the discharge current. That is, the controller 130 can set the magnitude of the charging current applied to each of the multiple battery cells 11 to a specific value. For example, the controller 130 can set the magnitude of the charging current to 2C-rate, but is not limited to this.

[0054] The controller 130 can adjust the charging time. According to this embodiment, the controller 130 can adjust the charging time to be longer than the discharge time of the resistance measuring unit 120. That is, the controller 130 can adjust the length of the charging time for which a charging current is applied to each of the plurality of battery cells 11 to be longer than the discharge time for which the resistance measuring unit 120 discharges each of the plurality of battery cells 11.

[0055] The controller 130 can set a pause time. The controller 130 can set a pause time between the charging time and the discharging time. Here, the pause time can be defined as the time between the charging time and the discharging time. Also, if the diagnostic time for each of the multiple battery cells 11 is fixed, the length of the pause time can be the total time minus the charging time and the discharging time.

[0056] The controller 130 can maintain the current of each of the multiple battery cells 11 within a predetermined range during the idle period. For example, the controller 130 can maintain the current of each of the multiple battery cells 11 at zero during the idle period.

[0057] According to the embodiment, the controller 130 can select a compensation battery cell. The controller 130 can select a compensation battery cell from a plurality of battery cells 11 included in the battery pack.

[0058] According to the embodiment, the controller 130 can select a compensation battery cell based on its manufacturing date. The controller 130 can determine whether the manufacturing date of each of the multiple battery cells 11 is earlier than the reference date, and select a compensation battery cell based on the determination result. For example, the controller 130 can extract battery cells from the multiple battery cells 11 whose manufacturing date is earlier than the reference date, and select the extracted battery cells as compensation battery cells. In other words, the controller 130 can select battery cells that have been in use for a certain period of time as compensation battery cells.

[0059] According to the embodiment, the controller 130 can select a compensation battery cell based on the State of Charge (SOC). The controller 130 can determine whether the SOC of each of the multiple battery cells 11 is less than the reference SOC and select a compensation battery cell based on the determination result. For example, the controller 130 can extract battery cells from the multiple battery cells 11 whose SOC is less than the reference SOC and select the extracted battery cells as compensation battery cells. In other words, the controller 130 can select battery cells whose SOC has decreased due to storage as compensation battery cells.

[0060] According to the embodiment, the controller 130 can charge the compensation battery cell by applying current. That is, the controller 130 can apply a charging current to a compensation battery cell selected from a plurality of battery cells 11.

[0061] The controller 130 can determine the assembly status. The controller 130 can determine the assembly status of the multiple battery cells 11 included in the battery pack. According to the embodiment, the controller 130 can determine the assembly status of each of the multiple battery cells 11 based on the cell resistance of each of the multiple battery cells 11. For example, the controller 130 can determine that the assembly status of a battery cell among the multiple battery cells 11 whose cell resistance is greater than or equal to a pre-set resistance is poor. The controller 130 can also determine that the assembly status of a battery cell among the multiple battery cells 11 whose cell resistance is less than a pre-set resistance is normal. Here, the pre-set resistance can be set based on the type of battery cell, the type of battery pack, etc.

[0062] According to the embodiment, the battery diagnostic device 100 can provide assembly status information to the user. For example, the battery diagnostic device 100 can provide assembly status information of the battery cells to a user terminal or PC via a communication unit (not shown), and it can also provide assembly status information of the battery cells via a display provided in a vehicle or charger.

[0063] Figure 3 shows the operation of a battery diagnostic device according to one embodiment disclosed in this document to compensate for an increase in the resistance of a battery cell.

[0064] Referring to Figure 3, the battery diagnostic device 100 can determine the assembly status of each of the multiple battery cells 11. The battery diagnostic device 100 can measure the cell resistance of each of the multiple battery cells 11 based on charging, rest, and resistance measurement operations, and determine the assembly status based on the cell resistance.

[0065] The charging current applied by the controller 130 to each of the multiple battery cells 11 can be a[A], and the discharge current discharged by the resistance measuring unit 120 can be b[A]. In this case, the controller 130 can adjust the magnitude of the charging current a to be greater than the magnitude of the discharge current b. That is, a can be greater than b. According to one embodiment, the controller 130 may adjust the magnitude of the charging current a to be greater than 2b, which is twice the magnitude of the discharge current.

[0066] The time t1 is when the controller 130 applies a charging current to each of the battery cells 11, and the time t3-t2 is when the resistance measuring unit 120 discharges each of the battery cells 11. In this case, the controller 130 can adjust the charging time t1 to be longer than the resistance measuring time t3-t2. That is, the time the controller 130 applies the charging current can be longer than the time the resistance measuring unit 120 measures the resistance by discharge.

[0067] A pause can be placed between the charging time and the resistance measurement time. That is, the pause can be the time from t1, when the charging time ends, to t2, when the resistance measurement time begins. The controller 130 can maintain the current of the multiple battery cells 11 within a predetermined range during the pause.

[0068] The battery diagnostic device 100 can determine the assembly status of the battery cells. The battery diagnostic device 100 can determine the assembly status of the battery cells based on the cell resistance of the battery cells.

[0069] The battery diagnostic device 100 can compensate for the increase in resistance of the battery cells by applying a charging current, thereby improving the accuracy of determining the assembly state of the battery cells.

[0070] Figure 4 is a flowchart showing a battery diagnostic method according to one embodiment disclosed in this document.

[0071] The embodiment shown in Figure 4 is only one embodiment, and the sequence of operations in the various embodiments of the present invention may differ from that shown in Figure 4. Some of the steps shown in Figure 4 may be omitted, the order of the steps may be changed, or steps may be merged.

[0072] Referring to Figure 4, the battery diagnostic method may include the following steps: obtaining the manufacturing date or State of Charge (SOC) of each of the multiple battery cells (S100); selecting a compensation battery cell from the multiple battery cells based on at least one of the manufacturing date or SOC (S200); applying a predetermined charging current to each of the compensation battery cells for a predetermined charging time (S300); measuring the cell resistance of each of the compensation battery cells based on their respective discharge current and discharge voltage (S400); determining whether the cell resistance is above a set value (S500); determining that the assembly state of the battery cells is defective (S600); and determining that the assembly state of the battery cells is normal (S700).

[0073] The operations S100 to S700 described above will be explained in detail below with reference to Figures 1 to 4.

[0074] In operation S100, the battery diagnostic device 100 can obtain the manufacturing date or SOC (State of Charge) of each of the multiple battery cells 11.

[0075] According to the embodiment, the battery diagnostic device 100 can acquire manufacturing date information. That is, the battery diagnostic device 100 can acquire the manufacturing date information for each of the multiple battery cells 11. For example, the battery diagnostic device 100 can acquire manufacturing date information by receiving the manufacturing date information corresponding to each of the multiple battery cells 11 from another storage unit or server.

[0076] According to the embodiment, the battery diagnostic device 100 can acquire State of Charge (SOC) information. That is, the battery diagnostic device 100 can acquire the SOC information for each of the multiple battery cells 11. For example, the battery diagnostic device 100 can acquire SOC information by directly measuring the SOC of each of the multiple battery cells 11, or by receiving the SOC information corresponding to each of the multiple battery cells 11 from another storage unit or server.

[0077] In operation S200, the battery diagnostic device 100 can select a compensation battery cell from a plurality of battery cells 11 based on at least one of the manufacturing date or SOC.

[0078] According to the embodiment, the battery diagnostic device 100 can select a compensation battery cell. The battery diagnostic device 100 can select a compensation battery cell from a plurality of battery cells 11 included in the battery pack.

[0079] According to the embodiment, the battery diagnostic device 100 can select a compensation battery cell based on its manufacturing date. The battery diagnostic device 100 can determine whether the manufacturing date of each of the multiple battery cells 11 is earlier than the reference date and select a compensation battery cell based on the determination result. For example, the battery diagnostic device 100 can extract battery cells from the multiple battery cells 11 whose manufacturing date is earlier than the reference date and select the extracted battery cells as compensation battery cells. In other words, the battery diagnostic device 100 can select battery cells that have been in use for a certain period of time as compensation battery cells.

[0080] According to the embodiment, the battery diagnostic device 100 can select a compensating battery cell based on the State of Charge (SOC). The battery diagnostic device 100 can determine whether the SOC of each of the multiple battery cells 11 is less than the reference SOC and select a compensating battery cell based on the determination result. For example, the battery diagnostic device 100 can extract battery cells from the multiple battery cells 11 whose SOC is less than the reference SOC and select the extracted battery cells as compensating battery cells. In other words, the battery diagnostic device 100 can select battery cells whose SOC has decreased due to storage as compensating battery cells.

[0081] According to this embodiment, operations S100 and S200 can be omitted. In this case, the battery diagnostic device 100 can perform operation S300 on all battery cells included in the battery pack without selecting a compensation battery cell. For the sake of explanation, the following description will assume that the battery diagnostic method includes operations S100 and S200.

[0082] In operation S300, the battery diagnostic device 100 can apply a predetermined charging current to each of the compensating battery cells for a predetermined charging time.

[0083] The battery diagnostic device 100 can apply a charging current to the compensating battery cells. The battery diagnostic device 100 can either directly apply a charging current to each of the multiple compensating battery cells, or control a separately provided charger or the like to apply a charging current to each of the multiple compensating battery cells.

[0084] In operation S400, the battery diagnostic device 100 can measure the cell resistance of each compensating battery cell based on the discharge current and discharge voltage of each compensating battery cell.

[0085] The battery diagnostic device 100 can measure the cell resistance of a battery cell. The battery diagnostic device 100 can measure the cell resistance of each of the multiple battery cells 11 contained in the battery pack.

[0086] According to one embodiment, the battery diagnostic device 100 can measure cell resistance using the DCIR (Direct Current Internal Resistance) method. In this case, the battery diagnostic device 100 can measure the voltage drop by discharging each of the multiple battery cells 11 with a predetermined discharge current, and measure the cell resistance of each of the multiple battery cells 11 based on the discharge current value and the voltage drop value. That is, the battery diagnostic device 100 can measure the cell resistance of each of the multiple battery cells 11 by discharging each of the multiple battery cells 11 during the discharge time based on the discharge current and discharge voltage.

[0087] In operation S500, the battery diagnostic device 100 can determine whether the cell resistance is equal to or greater than the set value. If the cell resistance is equal to or greater than the set value, operation S600 can be performed. If the cell resistance is less than the set value, operation S700 can be performed.

[0088] In operation S600, the battery diagnostic device 100 can determine that the assembly state of the battery cells is defective. The battery diagnostic device 100 can determine that the assembly state of any of the multiple battery cells 11 whose cell resistance is greater than or equal to a previously set resistance is defective.

[0089] In operation S700, the battery diagnostic device 100 can determine that the assembly state of the battery cells is normal. The battery diagnostic device 100 can determine that the assembly state of the battery cells among the multiple battery cells 11 whose cell resistance is less than a previously set resistance is normal.

[0090] Figure 5 shows a computing system that performs one embodiment of the battery diagnostic method disclosed in this document.

[0091] Referring to Figure 5, the computing system 200 according to one embodiment disclosed in this document may include an MCU 210, a memory 220, an input / output I / F 230, and a communication I / F 240.

[0092] The MCU210 is a processor that executes various programs stored in the memory 220 (for example, a SOH calculation program, a cell balancing target determination program, etc.), processes various data including SOC and SOH of multiple battery cells using such programs, and performs the functions of the battery diagnostic device 100 described above with reference to Figures 1 to 3.

[0093] Memory 220 can store various programs related to calculating the State of Health (SOH) of battery cells and determining which cells are eligible for cell balancing. Memory 220 can also store various data such as the State of Charge (SOC) and SOH data for each battery cell.

[0094] Multiple such memories 220 may be provided as needed. The memory 220 may be volatile or non-volatile. As a volatile memory, RAM, DRAM, SRAM, etc., can be used. As a non-volatile memory, ROM, PROM, EAROM, EPROM, EEPROM, flash memory, etc., can be used. The examples of memory 220 listed above are merely illustrative and the invention is not limited to these examples.

[0095] The input / output interface 230 can provide an interface that connects the MCU 210 to input devices (not shown) such as keyboards, mice, and touch panels, and output devices (not shown) such as displays, enabling data transmission and reception.

[0096] The communication interface 240 is configured to send and receive various data with a server and can be various devices that support wired or wireless communication. For example, via the communication interface 240, programs for calculating the state of health (SOH) of battery cells and determining which cells are to be balanced, as well as various other data, can be sent and received from a separately provided external server.

[0097] Thus, the battery diagnostic method according to one embodiment disclosed in this document can be recorded in the memory 220 and executed by the MCU 210.

[0098] The above description is merely illustrative of the technical concept disclosed in this document, and any person with ordinary skill in the art to which the embodiments disclosed in this document belong can make various modifications and variations without departing from the essential characteristics of the embodiments disclosed in this document.

[0099] Therefore, the embodiments disclosed herein are for illustrative purposes only, and not to limit the technical concept disclosed herein, and such embodiments do not limit the scope of the technical concept disclosed herein. The scope of protection for the technical concept disclosed herein should be interpreted in accordance with the attached claims, and all technical concepts within an equivalent scope should be interpreted as being included in the scope of rights of this document.

Claims

1. An information acquisition unit configured to measure the current and voltage of each of multiple battery cells, A resistance measuring unit configured to measure the cell resistance of each of the plurality of battery cells based on the discharge current and discharge voltage of each of the plurality of battery cells, Before the resistance measurement by the resistance measuring unit, a predetermined charging current is applied to each of the plurality of battery cells for a predetermined charging time. A battery diagnostic device comprising: a controller configured to determine the assembly state of each of the plurality of battery cells based on the cell resistance.

2. The information acquisition unit acquires the manufacturing date of each of the plurality of battery cells, The controller determines whether the manufacturing date of each of the plurality of battery cells is earlier than the reference date. The battery diagnostic device according to claim 1, further configured to select a compensation battery cell from the plurality of battery cells based on the judgment result.

3. The battery diagnostic device according to claim 2, wherein the controller is further configured to apply the charging current to the compensating battery cell.

4. The information acquisition unit is further configured to acquire the State of Charge (SOC) of each of the plurality of battery cells. The controller determines whether the SOC of each of the plurality of battery cells is less than the reference SOC, The battery diagnostic device according to claim 1, further configured to select a compensation battery cell from the plurality of battery cells based on the judgment result.

5. The battery diagnostic device according to claim 1, wherein the controller is further configured to adjust the magnitude of the charging current to twice or more the magnitude of the discharge current.

6. The battery diagnostic device according to claim 1, wherein the controller is further configured to maintain the current of each of the plurality of battery cells within a predetermined range between the charging time and the resistance measurement of the resistance measuring unit.

7. The resistance measuring unit is further configured to discharge each of the plurality of battery cells during a predetermined discharge time and to measure the cell resistance of each of the plurality of battery cells. The battery diagnostic device according to claim 1, wherein the controller is further configured to adjust the pre-set charging time to be longer than the pre-set discharging time.

8. The battery diagnostic device according to claim 1, wherein the resistance measuring unit is further configured to measure the cell resistance of each of the plurality of battery cells using the DCIR (Direct Current Internal Resistance) method.

9. The battery diagnostic device according to claim 1, wherein the controller is further configured to determine that the assembly state of a battery cell among the plurality of battery cells is defective if its cell resistance is greater than or equal to a previously set resistance.

10. The steps include applying a predetermined charging current to each of the multiple battery cells for a predetermined charging time, The steps include measuring the cell resistance of each of the plurality of battery cells based on the discharge current and discharge voltage of each of the plurality of battery cells, A battery diagnostic method comprising the step of determining the assembly state of each of the plurality of battery cells based on the cell resistance.

11. The steps include obtaining the manufacturing date or State of Charge (SOC) for each of the plurality of battery cells, The battery diagnostic method according to claim 10, further comprising the step of selecting a compensating battery cell from the plurality of battery cells based on the manufacturing date or at least one of the SOC.

12. The battery diagnostic method according to claim 10, wherein the magnitude of the charging current is twice or more the magnitude of the discharge current.

13. The step of measuring the cell resistance involves discharging each of the plurality of battery cells during a predetermined discharge time and measuring the cell resistance of each of the plurality of battery cells. The battery diagnostic method according to claim 10, wherein the previously set charging time is longer than the previously set discharging time.

14. The battery diagnostic method according to claim 10, wherein the step of measuring the cell resistance is a step of measuring the cell resistance of each of the plurality of battery cells using the DCIR (Direct Current Internal Resistance) method.

15. The battery diagnostic method according to claim 10, wherein the step of determining the assembly state is to determine that the assembly state of a battery cell among the plurality of battery cells is poor if the cell resistance is greater than or equal to a previously set resistance.

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