Battery resistance diagnosis device and method

Abstract

To provide a battery resistance diagnosis device and method for diagnosing a resistance abnormality by detecting a sudden change in resistance in a battery cell and a battery sensing line.SOLUTION: A battery resistance diagnosis device includes a current supply unit configured to supply a preset fixed current to a battery cell, a voltage measurement unit configured to measure an open circuit voltage of the battery cell while the fixed current is supplied, an external resistance calculation unit configured to calculate an external resistance value of the battery based on the fixed current and the open circuit voltage of the battery cell, and an abnormality diagnosis unit configured to diagnose a battery abnormality due to a voltage drop by comparing the calculated external resistance value with a preset external resistance value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS]

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0088426, filed on July 22, 2019, the entire contents of which are incorporated herein by reference.

[0003] [Technical field]

[0004] The present invention relates to a battery resistance diagnosis device and method for diagnosing resistance abnormalities by detecting sudden changes in the resistance of battery cells and battery sensing wires. [Background technology]

[0005] Generally, an increase in battery resistance causes errors in measuring the battery cell voltage. Conventionally, to diagnose the resistance at the measurement terminal of a battery cell voltage, an external resistance element, a maximum current, and a maximum voltage drop are used to determine the increase in resistance due to the voltage drop. In this type of algorithm, if the voltage measured in the intended diagnostic mode becomes larger than the maximum voltage drop (threshold), it is determined that the resistance has suddenly increased, and an abnormality is diagnosed in the battery system.

[0006] However, in conventional battery cell resistance diagnosis methods, the actual threshold value changes depending on the situation because the voltage, SOC, and current of each battery cell are not the same. Therefore, in battery systems, the threshold value is defined as a maximum value taking this fact into consideration, and the system operates at a fixed threshold value throughout its life cycle. In this method, the threshold value does not reflect variations due to battery product manufacturing, and the golden sample standard may result in the threshold value being set too high.

[0007] As described above, the conventional method for diagnosing the resistance of a battery cell has the problem that it is difficult to accurately diagnose the resistance of the cell voltage measurement terminal of the battery. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to provide a battery resistance diagnosis device and method that can accurately diagnose sudden changes in the resistance of a battery cell by detecting the resistance of the battery cell when each battery cell has the same voltage and current, i.e., when the battery is fully charged, and that can contribute to more accurate cell voltage measurement by diagnosing the resistance caused by cell voltage measurement errors. [Means for solving the problem]

[0009] A battery resistance diagnosis device according to one embodiment of the present invention may include a current supply unit that supplies a preset fixed current to a battery cell, a voltage measurement unit that measures the open-circuit voltage of the battery cell while the fixed current is being supplied, an external resistance calculation unit that calculates an external resistance value of the battery based on the fixed current and the open-circuit voltage of the battery cell, and an abnormality diagnosis unit that diagnoses a battery abnormality due to a voltage drop by comparing the calculated external resistance value with a preset external resistance value.

[0010] The voltage measurement unit in the battery resistance diagnosis device according to one embodiment of the present invention may include a memory that measures the open-circuit voltage of the battery cell at regular intervals and accumulates and stores the external resistance value calculated at regular intervals based on the open-circuit voltage of the battery cell measured at regular intervals.

[0011] The preset external resistance value in the battery resistance diagnosis device according to one embodiment of the present invention is the external resistance value that is first calculated by the external resistance calculation unit after the battery cell is fully charged, and the abnormality diagnosis unit can diagnose a battery abnormality based on whether the difference between the calculated external resistance value and the preset external resistance value is outside a certain range.

[0012] The certain range in the battery resistance diagnosis device according to one embodiment of the present invention may be 10% of the external resistance value initially calculated by the external resistance calculation unit.

[0013] Among the external resistance values calculated at regular intervals and stored in memory in a battery resistance diagnosis device according to one embodiment of the present invention, the preset external resistance value is an external resistance value calculated in a calculation cycle before the calculated external resistance value is calculated and stored in memory, and the abnormality diagnosis unit can diagnose a battery abnormality based on whether the amount of change from the preset external resistance value to the calculated external resistance value falls outside a certain range.

[0014] The certain range in a battery resistance diagnosis device according to one embodiment of the present invention may be 200% of the amount of change to the resistance value stored in memory in the calculation cycle immediately before the calculated external resistance value is calculated.

[0015] The battery resistance value in the battery resistance diagnosis device according to one embodiment of the present invention may include at least one resistance value among the internal resistance of the battery cell, the lead resistance of the connecting portion of the battery cell, the busbar resistance, the FPC (Flexible Printed Circuit) resistance, the PCB (Printed Circuit Board) resistance, and the connector resistance.

[0016] The fixed current in the battery resistance diagnostic device according to one embodiment of the present invention may be a current in a battery balancing circuit.

[0017] A battery resistance diagnosis method according to one embodiment of the present invention may include the steps of: supplying a preset fixed current to a battery cell; measuring the open-circuit voltage of the battery cell while the fixed current is being supplied; calculating an external resistance value of the battery based on the fixed current and the open-circuit voltage of the battery cell; and diagnosing a battery abnormality due to a voltage drop by comparing the calculated external resistance value with the preset external resistance value.

[0018] In a battery resistance diagnosis method according to an embodiment of the present invention, the step of measuring the open-circuit voltage of the battery cell may include the steps of measuring the open-circuit voltage of the battery cell at regular intervals, accumulating the external resistance value calculated at regular intervals based on the open-circuit voltage of the battery cell measured at regular intervals, and storing the accumulated external resistance value in a memory.

[0019] In a battery resistance diagnosis method according to one embodiment of the present invention, the preset external resistance value is the external resistance value calculated initially after the battery cell is fully charged, and the step of diagnosing a battery abnormality can diagnose the battery abnormality based on whether the difference between the calculated external resistance value and the preset external resistance value is outside a certain range.

[0020] In the battery resistance diagnosis method according to one embodiment of the present invention, the certain range may be 10% of the initially calculated external resistance value.

[0021] In a battery resistance diagnosis method according to one embodiment of the present invention, among the external resistance values calculated at regular intervals and stored in memory, the preset external resistance value is an external resistance value calculated in a calculation cycle before the calculated external resistance value is calculated and stored in memory, and the step of diagnosing a battery abnormality can diagnose the battery abnormality based on whether the amount of change from the preset external resistance value to the calculated external resistance value falls outside a certain range.

[0022] In a battery resistance diagnosis method according to one embodiment of the present invention, the certain range may be 200% of the change in the resistance value stored in the memory in the calculation cycle immediately before the calculated external resistance value is calculated.

[0023] In the battery resistance diagnosis method according to an embodiment of the present invention, the resistance value of the battery may include at least one resistance value of the internal resistance of the battery cell, the lead resistance of the connection portion of the battery cell, the bus bar resistance, the FPC resistance, the PCB resistance, and the connector resistance.

[0024] In the battery resistance diagnosis method according to one embodiment of the present invention, the fixed current may be a current of a balancing circuit of the battery. [Effects of the Invention]

[0025] According to the battery resistance diagnosis device and method of the present invention, when each battery cell has the same voltage and current, i.e., when it is fully charged, detecting the resistance of the battery cell makes it possible to accurately diagnose sudden changes in the resistance of the battery cell, and diagnosing the resistance caused by cell voltage measurement errors can contribute to more accurate cell voltage measurement. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a block diagram showing a configuration of a general battery management system.

[0027] [Figure 2] 1 is a block diagram showing the configuration of a battery resistance diagnosis device according to an embodiment of the present invention;

[0028] [Figure 3] 1 shows the configuration of a resistor at a cell voltage measurement terminal of a battery according to an embodiment of the present invention.

[0029] [Figure 4] 3 is a flowchart of a battery resistance diagnosis method according to an embodiment of the present invention.

[0030] [Figure 5] 10 is a flowchart of a battery resistance diagnosis method according to another embodiment of the present invention.

[0031] [Figure 6] 1 is a block diagram showing a hardware configuration of a battery resistance diagnosis device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification, the same reference numerals are used to refer to the same components in the drawings, and redundant description of the same components will be omitted.

[0033] Specific structural or functional descriptions of the various embodiments of the present invention disclosed herein are merely exemplary for purposes of describing the embodiments of the present invention, and the various embodiments of the present invention may be embodied in various forms and should not be construed as being limited to the embodiments set forth herein.

[0034] The terms "first," "second," "primary," or "second" used in various embodiments may modify various components regardless of order and / or importance, and do not limit the components. For example, a first component may be named as a second component, and similarly, a second component may be named in place of the first component, without departing from the scope of the present invention.

[0035] The terms used in this specification are merely used to describe particular embodiments and are not intended to limit the scope of other embodiments. The singular expression can include the plural expression unless clearly defined differently in the context.

[0036] All terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by a person of ordinary skill in the art of the present invention. Terms defined in commonly used dictionaries may be interpreted as having the same or similar meaning as the meaning they have in the context of the relevant art, and unless explicitly defined herein, they should not be interpreted in an ideal or overly formal sense. In some cases, even terms defined herein should not be interpreted to exclude embodiments of the present invention.

[0037] FIG. 1 is a block diagram showing the configuration of a general battery management system.

[0038] Referring to FIG. 1, there is shown a schematic diagram of a battery control system including a battery pack 1 according to one embodiment of the present invention and a host controller 2 included in the host system.

[0039] As shown in FIG. 1 , the battery pack 1 includes a rechargeable battery module 10 consisting of one or more battery cells; a switching unit 14 connected in series to the positive or negative terminal of the battery module 10 to control the flow of charge / discharge current through the battery module 10; and a battery management system 20 that monitors the voltage, current, temperature, etc. of the battery module 10 and controls the battery to prevent overcharging and overdischarging. While the battery management system 20 is described as being connected to the battery module, it can also be connected to each battery cell to monitor and measure the voltage, current, temperature, etc. of the battery cell. A battery cell management system (not shown) is provided for each battery cell, and each of the multiple battery cell management systems can transmit and receive data to and from the battery management system 20, which monitors and controls the battery module. The battery cell management system is similar in operation and function to the battery management system 20.

[0040] Here, the switching unit 14 may use, for example, at least one MOSFET as a semiconductor switching element for controlling the flow of current for charging or discharging the battery module 10.

[0041] In addition, the BMS 20 can measure or calculate the voltage and current of the gate, source, drain, etc. of the semiconductor switching element in order to monitor the voltage, current, temperature, etc. of the battery pack module 10, and can also measure the current, voltage, temperature, etc. of the battery module using a sensor 12 provided adjacent to the semiconductor switching element 14. The BMS 20 is an interface that receives input of measured values of the various parameters described above, and can include a plurality of terminals and circuits connected to these terminals that process the received input values.

[0042] The BMS 20 can also control the ON / OFF of the switching elements 14, such as MOSFETs, and is connected to the battery modules 10 to monitor the status of the battery modules 10.

[0043] The upper controller 2 can transmit control signals for the battery modules to the BMS 20. This allows the BMS 20 to control its operation based on signals applied from the upper controller. The battery cell of the present invention may be included in a battery pack used in an ESS or a vehicle, etc. However, the present invention is not limited to such applications.

[0044] Such a configuration of the battery pack 1 and the configuration of the BMS 20 are well known, and therefore a more detailed description thereof will be omitted.

[0045] Meanwhile, the battery cell diagnostic device according to the embodiment of the present invention is connected to each of the plurality of battery cells connected in series within the battery module 10, and is capable of determining abnormalities in the battery cells.

[0046] FIG. 2 is a block diagram showing the configuration of a battery resistance diagnosis device according to one embodiment of the present invention.

[0047] Referring to FIG. 2, a battery resistance diagnosis device 100 according to an embodiment of the present invention may include a current supply unit 110, a voltage measurement unit 120, an external resistance calculation unit 130, an abnormality diagnosis unit 140, and a memory 150.

[0048] The current supply unit 110 may supply a preset fixed current to the battery cells. For example, the fixed current supplied from the current supply unit 110 may be a current used in a battery balancing circuit (not shown).

[0049] Here, the battery balancing circuit is a circuit consisting of resistors connected to both ends of each battery cell and switching elements, and controls the switching elements to turn on / off according to the control of a Battery Management System (BMS), and consumes the balancing current of the battery cells through the resistors to lower the voltage, thereby adjusting the voltage of each battery cell to be equal.

[0050] In particular, the battery resistance diagnosis device 100 according to an embodiment of the present invention can perform measurement when the battery cells are fully charged and the battery is in an open circuit voltage (OCV) state. In this manner, the current supply unit 110 can more accurately diagnose abnormalities by performing measurement when each battery cell is fully charged (e.g., before entering sleep mode), that is, when each battery cell has the same voltage and current.

[0051] The voltage measurement unit 120 may measure the open-circuit voltage of the battery cell while a fixed current is supplied by the current supply unit 110. In this case, the voltage measurement unit 120 may measure a voltage generated when a fixed current used in an existing battery balancing circuit is supplied by the current supply unit 110 to a resistance of the battery cell and a sensing line, etc.

[0052] Furthermore, the voltage measurement unit 120 can measure the open circuit voltage of the battery cell at regular intervals. In this case, the measurement interval can be arbitrarily set by the user of the battery resistance diagnosis device 100 according to one embodiment of the present invention.

[0053] The external resistance calculation unit 130 can calculate the external resistance value of the battery based on the fixed current supplied by the current supply unit 110 and the open-circuit voltage of the battery cell measured by the voltage measurement unit 120. For example, the external resistance calculation unit 130 can calculate the external resistance value of the battery cell by dividing the open-circuit voltage when the battery is fully charged (100%) by the current of the balancing circuit.

[0054] Here, the external resistance of the battery cell may include not only the internal resistance of the battery cell but also at least one of the resistance of the lead, busbar, flexible printed circuit (FPC), printed circuit board (PCB), and connector at the connection portion of the battery cell, as will be described later with reference to FIG.

[0055] Furthermore, the external resistance calculation unit 130 can calculate the amount of change in the resistance value based on the difference between the calculated external resistance value and the external resistance value previously stored in the memory 150 (i.e., the external resistance value calculated in the calculation cycle before the external resistance value is calculated by the external resistance calculation unit 130). For example, the amount of change in the resistance value may be the difference between the currently calculated external resistance value and the external resistance value stored in the memory 150 that was calculated in the immediately preceding calculation cycle.

[0056] The abnormality diagnosis unit 140 can diagnose a battery abnormality due to a voltage drop by comparing the external resistance value calculated by the external resistance calculation unit 130 with a preset external resistance value.

[0057] Specifically, the abnormality diagnosis unit 140 can diagnose an abnormality in the battery based on whether the difference between the resistance value calculated by the external resistance calculation unit 130 and the resistance value initially calculated by the external resistance calculation unit 130 after the battery cell is fully charged (i.e., the resistance value initially stored in the memory 150) is outside a certain range. In this case, the external resistance value initially calculated by the external resistance calculation unit 130 after the battery cell is fully charged may be stored in the memory 150. Furthermore, the certain range may be 10% of the external resistance value initially calculated by the external resistance calculation unit 130.

[0058] Furthermore, the abnormality diagnosis unit 140 can diagnose an abnormality in the battery based on whether the amount of change in the external resistance value calculated by the external resistance calculation unit 130 is outside a certain range. In this case, the amount of change in the external resistance value may include the amount of change from the external resistance value calculated and stored in memory in a calculation cycle before the calculated external resistance value is calculated, to the resistance value calculated by the external resistance calculation unit 130. Furthermore, the certain range may be 200% of the amount of change to the resistance value calculated in a calculation cycle immediately before the external resistance value is calculated by the external resistance calculation unit 130 (i.e., the amount of change in the external resistance value calculated in the immediately preceding calculation cycle).

[0059] Meanwhile, the specific ranges detailed for the external resistance value and the amount of change in the external resistance value in the abnormality diagnosis unit 140 do not necessarily have to be fixed values and can be changed. For example, the abnormality diagnosis unit 140 can diagnose an abnormality in the battery by analyzing patterns such as trends and fluctuations in the external resistance value and the amount of change in the external resistance value using various analytical methods such as machine learning and big data analysis, and detecting whether or not they deviate from a normal pattern.

[0060] The memory 150 can accumulate and store the external resistance value and the amount of change in the external resistance value calculated at regular intervals based on the open-circuit voltage of the battery cell measured at regular intervals by the voltage measurement unit 120. Therefore, the abnormality diagnosis unit 140 can determine whether or not there is an abnormality in the battery using the external resistance value stored in the memory 150. In this case, the period at which the memory 150 stores the external resistance value and the amount of change in the external resistance value can be arbitrarily set by the user of the battery resistance diagnosis device 100 according to one embodiment of the present invention.

[0061] Thus, according to the battery resistance diagnosis device of one embodiment of the present invention, when each battery cell has the same voltage and current, i.e., when the battery is fully charged, detecting the resistance of the battery cell makes it possible to accurately diagnose sudden changes in the resistance of the battery cell, and diagnosing the resistance caused by cell voltage measurement errors can contribute to more accurate cell voltage measurement.

[0062] FIG. 3 shows the configuration of the resistance at the cell voltage measurement terminal of the battery according to one embodiment of the present invention.

[0063] Referring to FIG. 3, a cell voltage measuring terminal 30 of a battery according to an embodiment of the present invention may include a battery cell 31, a sensing line 32, and a CMC (Cell Management Controller) 33.

[0064] The battery resistance diagnosis device according to one embodiment of the present invention can measure not only the internal resistance (1) of the battery cell 31 but also all external resistance elements, such as lead resistance (2) of the battery cell connection portion included in the sensing line 32 between the battery cell 31 and the CMC 33, bus bar resistance (3), FPC plate resistance (4), FPC connection portion resistance (5), and PCB pattern and connector resistance (6). However, the resistance elements shown in FIG. 3 are merely exemplary, and any other resistance elements that affect the increase (deterioration) of the resistance of the battery cell 31 may be included.

[0065] For example, the CMC 33 may be a slave battery management system (BMS). In this case, a slave battery management system is disposed in each battery cell. Each slave battery management system measures and monitors the temperature, voltage, or current of multiple battery cells, transmits the monitored information to a host system, and receives control commands for the battery cells from the host system to control the connected battery cells.

[0066] The CMC 33 shown in Figure 3 may include a processor that performs the battery cell diagnostic functions described in Figure 2. The CMC may also include a battery cell balancing circuit to supply a fixed current to the battery cells for resistance calculation.

[0067] FIG. 4 is a flowchart of a battery resistance diagnosis method according to one embodiment of the present invention.

[0068] First, when the battery cells are fully charged and switched to an open circuit voltage state, a preset fixed current is supplied to the battery cells (S110), where the supplied fixed current may be a current used in a battery balancing circuit.

[0069] In this way, in step S110, by starting the measurement when the battery cells are fully charged, diagnosis can be performed under the same voltage and current, thereby reducing measurement errors caused by differences in voltage, SOC, current, etc. between battery cells in conventional battery systems.

[0070] Then, while a fixed current is supplied to the battery cell, the open-circuit voltage of the battery cell is measured (S120). In this case, it is possible to measure the voltage generated when a fixed current used in an existing battery balancing circuit is supplied to the resistance of the battery cell and the sensing line. Also, in step S120, the open-circuit voltage of the battery cell can be measured at a fixed interval. In this case, the measurement interval can be arbitrarily set by a user of the battery resistance diagnosis device according to an embodiment of the present invention.

[0071] Next, the external resistance of the battery is calculated based on the fixed current and the open-circuit voltage of the battery cell (S130). In this case, the external resistance of the battery cell can be calculated by dividing the open-circuit voltage at full charge (100%) by the current of the balancing circuit. In step S140, the external resistance calculated in step S130 is stored in memory.

[0072] Then, it is determined whether the difference between the external resistance value calculated in step S130 and a preset external resistance value is outside a certain range (S150). For example, the preset external resistance value may include the external resistance value initially calculated after the battery cell is fully charged (i.e., the resistance value initially stored in memory 150). Alternatively, the certain range may be 10% of the initially calculated external resistance value.

[0073] If the difference between the external resistance value calculated in step S150 and the preset external resistance value is not outside the certain range (NO), the process returns to step S110.

[0074] If the difference between the external resistance value calculated in step S150 and the preset external resistance value is outside a certain range (YES), it is determined that an abnormality has occurred in the battery cell (S160).

[0075] As described above, according to FIG. 4, it is possible to detect whether or not a sudden change in resistance occurs based on whether or not the initially measured external resistance value deviates from a certain boundary value.

[0076] FIG. 5 is a flowchart of a battery resistance diagnosis method according to another embodiment of the present invention.

[0077] Steps S210 to S230 in FIG. 5 are the same as those in FIG. 4, and therefore detailed description thereof will be omitted here.

[0078] In step S240, the amount of change in the external resistance is calculated based on the difference between the calculated external resistance and the external resistance calculated in the calculation cycle before the calculated external resistance and stored in memory. For example, the amount of change in the external resistance may be the difference between the currently calculated resistance and the resistance calculated in the immediately preceding calculation cycle that is stored in memory. The calculated amount of change in the external resistance is then stored in memory (S250).

[0079] Next, it is determined whether the amount of change in the external resistance value is outside a certain range (S260). In this case, the certain range may be 200% of the amount of change in the resistance value stored in the memory in the calculation cycle immediately before the external resistance value is calculated (i.e., the amount of change in the external resistance value calculated in the calculation cycle immediately before).

[0080] If the external resistance value calculated in step S260 is not outside the certain range (NO), the process returns to step S210.

[0081] If the external resistance value calculated in step S260 is outside the certain range (YES), it is determined that an abnormality has occurred in the battery cell (S270).

[0082] As shown in FIG. 5, the amount of change in the external resistance value (for example, the amount of change in the resistance value calculated immediately before) can be used to diagnose whether the degree of resistance fluctuation (deterioration) relative to the stored data is progressing rapidly.

[0083] On the other hand, although the explanation here has been given separately using Figures 4 and 5, by detecting the resistance change according to Figure 4 and detecting the amount of change in resistance according to Figure 5 together, it is also possible to determine that an abnormality has occurred in the battery cell if both the external resistance value and the amount of change in the external resistance value exceed the reference value.

[0084] As described above, according to the battery resistance diagnosis method of one embodiment of the present invention, when each battery cell has the same voltage and current, i.e., when the battery is fully charged, detecting the resistance of the battery cell makes it possible to accurately diagnose a sudden change in resistance of the battery cell, and diagnosing the resistance caused by a measurement error in the cell voltage can contribute to more accurate cell voltage measurement.

[0085] FIG. 6 is a block diagram showing the hardware configuration of a battery resistance diagnosis device according to one embodiment of the present invention.

[0086] 6, the battery resistance diagnosis device 600 may include a microcontroller (MCU) 610 that controls various processes and components, a memory 620 that stores an operating system program and various programs (e.g., a battery pack abnormality diagnosis program or a battery pack temperature estimation program), an input / output interface 630 that provides an input interface and an output interface between the battery cell module and / or a switching unit (e.g., a semiconductor switching element), and a communication interface 640 that enables communication with an external device (e.g., a higher-level controller) via a wired or wireless communication network. In this way, the computer program according to the present invention may be stored in the memory 620 and processed by the microcontroller 610, thereby realizing, for example, a module that performs each of the functional blocks shown in FIG. 2.

[0087] Although all components constituting the embodiments of the present invention have been described as being combined into one or operating in combination, the present invention is not necessarily limited to these embodiments. That is, all components may be selectively combined into one or more other components and operate within the scope of the present invention.

[0088] Furthermore, unless otherwise specified to the contrary, terms such as "comprise," "comprise," or "have" mean that the relevant element may be present, and should be interpreted as including other elements rather than excluding other elements. All terms, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention pertains, unless otherwise defined. Commonly used terms, such as those defined in a dictionary, should be interpreted to be consistent with the contextual meaning of the relevant art, and should not be interpreted as having an idealized or overly formal meaning unless expressly defined in the present invention.

[0089] The above description merely exemplifies the technical concept of the present invention, and various modifications and variations are possible by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are for illustrative purposes only, and are not intended to limit the technical concept of the present invention. The scope of the present invention should be interpreted by the following claims, and all technical concepts within the scope of the claims should be interpreted as being within the scope of the present invention.

Claims

1. a current supply unit for supplying a balancing current to the battery cell after the battery cell is fully charged; a voltage measurement unit that measures the voltage across the battery cell at regular intervals while the balancing current is being supplied; a resistance calculation unit that calculates a resistance value of the battery cell based on the balancing current and the voltage across the battery cell; a memory for storing a resistance value calculated at regular intervals based on the voltage across the battery cell measured at regular intervals; an abnormality diagnosis unit that diagnoses a battery abnormality due to a voltage drop by comparing the calculated resistance value with a preset resistance value; the preset resistance value is a resistance value that is initially calculated by the resistance calculation unit after the battery cell is fully charged, The abnormality diagnosis unit diagnoses an abnormality in the battery based on whether or not the difference between the calculated resistance value and the preset resistance value is outside a first certain range.

2. 2. The battery resistance diagnosis device according to claim 1, wherein the first certain range is 10% of the resistance value initially calculated by the resistance calculation unit.

3. The battery resistance diagnosis device according to claim 1 , wherein the abnormality diagnosis unit sets the first certain range based on at least one of big data analysis and machine learning.

4. the preset resistance value is a resistance value calculated in a calculation cycle before the calculation of the calculated resistance value and stored in the memory, among resistance values calculated at a constant cycle and stored in the memory, 4. The battery resistance diagnosis device according to claim 1, wherein the abnormality diagnosis unit diagnoses an abnormality in the battery based on whether or not the amount of change from the preset resistance value to the calculated resistance value falls outside a second certain range.

5. 5. The battery resistance diagnosis device according to claim 4, wherein the second certain range is 200% of the amount of change to the resistance value stored in the memory in a calculation cycle immediately before the calculated resistance value is calculated.

6. The battery resistance diagnosis device according to claim 4 , wherein the abnormality diagnosis unit sets the second certain range based on at least one of big data analysis and machine learning.

7. 7. The battery resistance diagnosis device according to claim 1, wherein the resistance value of the battery cell includes at least one resistance value of an internal resistance of the battery cell, a lead resistance of a connection portion of the battery cell, a bus bar resistance, a flexible printed circuit (FPC) resistance, a printed circuit board (PCB) resistance, and a connector resistance.

8. providing a balancing current to the battery cells after the battery cells are fully charged; measuring a voltage across the battery cell at a constant period while the balancing current is being supplied; calculating a resistance value of the battery cell based on the balancing current and the voltage across the battery cell; storing a resistance value calculated at regular intervals based on the voltage across the battery cell measured at regular intervals in a memory; and diagnosing a battery abnormality due to a voltage drop by comparing the calculated resistance value with a preset resistance value; the preset resistance value is a resistance value calculated initially after the battery cell is fully charged, a step of diagnosing a battery abnormality based on whether a difference between the calculated resistance value and the predetermined resistance value is outside a first certain range;

9. 9. The battery resistance diagnosis method according to claim 8, wherein the first certain range is 10% of the initially calculated resistance value.

10. the preset resistance value is a resistance value calculated in a calculation cycle before the calculation of the calculated resistance value and stored in the memory, among resistance values calculated at a constant cycle and stored in the memory, 10. The battery resistance diagnosis method according to claim 8, wherein the step of diagnosing a battery abnormality diagnoses a battery abnormality based on whether or not an amount of change from the preset resistance value to the calculated resistance value falls outside a second certain range.

11. 11. The battery resistance diagnosis method according to claim 10, wherein the second certain range is 200% of the amount of change to the resistance value stored in the memory in a calculation cycle immediately before the calculated resistance value is calculated.

12. 12. The battery resistance diagnosis method according to claim 8, wherein the resistance value of the battery cell includes at least one resistance value of an internal resistance of the battery cell, a lead resistance of a connection portion of the battery cell, a bus bar resistance, an FPC resistance, a PCB resistance, and a connector resistance.

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