Battery management system and control method of battery management system

Abstract

The invention relates to a battery management system and a control method of the battery management system. A battery management system according to one embodiment of the present disclosure may include: an alarm module providing an alarm in a specified manner; an electrochemical impedance spectroscopy measurement module, namely an EIS measurement module, for measuring the electrochemical impedance spectroscopy, namely EIS, of the secondary battery; and a processor receiving an EIS measurement result from the EIS measurement module, calculating a real number intercept of an impedance value of the secondary battery based on the received EIS measurement result, determining whether the secondary battery is abnormal based on the calculated real number intercept, and when the determination result is that the secondary battery is abnormal, determining that the secondary battery is abnormal. And the processor controls the alarm module to provide an alarm so as to prompt that the secondary battery is abnormal. The present disclosure may improve accuracy and / or efficiency of sensing an abnormality of a secondary battery.

Description

Technical Field

[0001] The present disclosure relates to a battery management system and a control method of the battery management system. Background Art

[0002] A secondary battery is a battery that can be repeatedly charged and discharged. With the development of the information communication and display industries, secondary batteries are widely used as a power source for portable electronic communication devices such as cameras, mobile phones, tablet computers (personal computers, PCs), and notebook computers. In addition, in recent years, in order to use secondary batteries as a power source for environmentally friendly vehicles such as electric vehicles, battery packs including multiple battery modules are being developed.

[0003] The secondary battery includes a battery management system (BMS), which can measure and monitor various information such as current, voltage, temperature, battery state of charge (SOC), discharge state, health state (SOH), and / or remaining capacity through various sensors.

[0004] On the other hand, the battery management system can sense the abnormality of the secondary battery. For example, the battery management system can estimate the impedance of the secondary battery based on the equivalent circuit model (ECM), and use the estimation result to sense the abnormality of the secondary battery. The method of estimating the impedance of the secondary battery based on the equivalent circuit model (ECM) is to use the voltage response when the current changes. But the problem is that during the rest period and the constant current operation interval of the secondary battery, since the current does not change, it is difficult to accurately estimate the impedance based on the equivalent circuit model (ECM) during the rest period and the constant current operation interval. Therefore, the method of sensing the abnormality of the secondary battery based on ECM has the problem of low efficiency in terms of practicality.

[0005] Therefore, a solution capable of accurately sensing abnormalities of a secondary battery in the entire operating range is needed. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] According to one aspect of the present disclosure, a battery management system and a control method of the battery management system which improve efficiency of sensing abnormality of a secondary battery may be provided.

[0008] According to another aspect of the present disclosure, a battery management system and a control method of the battery management system may be provided, which are capable of compensating for a weakness of sensing an abnormality of a secondary battery based on an equivalent circuit model (ECM).

[0009] The battery management system and the control method of the battery management system disclosed in the present invention can be widely used in electric vehicles, battery charging stations and other green technology fields such as solar power generation and wind power generation using batteries. In addition, the battery management system and the control method of the battery management system disclosed in the present invention can be used in eco-friendly electric vehicles, hybrid vehicles, etc. that prevent climate change by suppressing air pollution and greenhouse gas emissions.

[0010] (II) Technical solution

[0011] A battery management system according to an embodiment of the present disclosure may include: an alarm module, which provides an alarm in a specified manner; an electrochemical impedance spectroscopy measurement module, i.e., an EIS measurement module, which measures the electrochemical impedance spectrum (EIS) of a secondary battery; and a processor, which receives an EIS measurement result from the EIS measurement module, calculates a real intercept of the impedance value of the secondary battery based on the received EIS measurement result, and determines whether the secondary battery has an abnormality based on the calculated real intercept. When the determination result is that the secondary battery has an abnormality, the processor controls the alarm module to provide an alarm to prompt that the secondary battery has an abnormality.

[0012] According to one embodiment, the EIS measurement module may measure the EIS of each battery cell or each battery module.

[0013] According to one embodiment, the processor may represent the impedance value of each of the battery cells or each of the battery modules as a Nyquist diagram in a rectangular coordinate system or a polar coordinate system, and may calculate the real intercept of each of the battery cells or each of the battery modules using the Nyquist diagram in the rectangular coordinate system or the polar coordinate system.

[0014] According to one embodiment, the processor may select a first point having a positive minimum value and a second point having a negative maximum value in the imaginary part of the impedance value, and may calculate the real intercept using the coordinate value of the first point, the coordinate value of the second point and a specified formula.

[0015] According to one embodiment, the processor may calculate a difference between a maximum value and a minimum value in the calculated real intercept, and when the calculated difference is greater than a specified first reference value, it may be determined that an abnormality occurs in the secondary battery.

[0016] According to one embodiment, the processor may calculate a standard deviation of the calculated real intercept, and when the calculated standard deviation is greater than a specified second reference value, it may be determined that an abnormality occurs in the secondary battery.

[0017] According to one embodiment, the processor may calculate a Z-score of the calculated real intercept, and when the calculated Z-score is greater than a specified third reference value, it may be determined that an abnormality occurs in the secondary battery.

[0018] According to one embodiment, the processor may control the EIS measurement module to measure the EIS during operation of a device including the secondary battery.

[0019] According to one embodiment, the processor can confirm whether it is a designated operating range. When the confirmation result is the designated operating range, the processor can determine whether the secondary battery has an abnormality based on the calculated real intercept. When the confirmation result is an operating range other than the designated operating range, the processor can estimate the impedance of the secondary battery using an equivalent circuit model (ECM) estimation module, and can determine whether the secondary battery has an abnormality using the estimation result based on the equivalent circuit model.

[0020] According to one embodiment, the EIS measurement module may apply a variable frequency within a specified range as an input signal to the secondary battery with a specified current amplitude, and may measure a voltage of the secondary battery.

[0021] According to an embodiment of the present disclosure, a control method of a battery management system may include: a step of measuring an electrochemical impedance spectroscopy (EIS) of a secondary battery by means of an EIS measurement module; a step of calculating a real intercept of an impedance value of the secondary battery based on the measured EIS; a step of judging whether the secondary battery has an abnormality based on the calculated real intercept; and a step of controlling an alarm module to provide an alarm to indicate that the secondary battery has an abnormality when the judgment result shows that the secondary battery has an abnormality.

[0022] According to one embodiment, the step of calculating the real intercept may include: representing the impedance value of the secondary battery in a Nyquist diagram of a rectangular coordinate system or a polar coordinate system; and calculating the real intercept of the impedance value using the Nyquist diagram of the rectangular coordinate system or the polar coordinate system.

[0023] According to one embodiment, the step of calculating the real intercept may include: the step of selecting a first point having a positive minimum value and a second point having a negative maximum value in the imaginary part of the impedance value; and the step of calculating the real intercept using the coordinate value of the first point, the coordinate value of the second point and a specified formula.

[0024] According to one embodiment, the step of determining whether the secondary battery has an abnormality may include: calculating the difference between the maximum value and the minimum value of the calculated real intercept; and determining that the secondary battery has an abnormality when the calculated difference is greater than a first reference value.

[0025] According to one embodiment, the step of determining whether the secondary battery has an abnormality may include: calculating a standard deviation of the calculated real intercept; and determining that the secondary battery has an abnormality when the calculated standard deviation is greater than a specified second reference value.

[0026] According to one embodiment, the step of determining whether the secondary battery has an abnormality may include: calculating a Z score of the calculated real intercept; and determining that the secondary battery has an abnormality when the calculated Z score is greater than a specified third reference value.

[0027] According to one embodiment, the step of measuring the EIS may be performed during operation of a device including the secondary battery.

[0028] According to one embodiment, the step of measuring the EIS may be performed in a designated partial operation interval of the operation interval of the secondary battery.

[0029] According to one embodiment, the method may further include a step of confirming whether it is a specified operating range, and the step of judging whether the secondary battery has an abnormality may include: when the confirmation result is the specified operating range, judging whether the secondary battery has an abnormality based on the calculated real intercept; and when the confirmation result is an operating range other than the specified operating range, estimating the impedance of the secondary battery using an equivalent circuit model (ECM) estimation module, and judging whether the secondary battery has an abnormality using the estimation result based on the equivalent circuit model.

[0030] According to one embodiment, the step of measuring the EIS may include the steps of applying a variable frequency within a specified range as an input signal to the secondary battery with a specified current amplitude, and measuring a voltage of the secondary battery.

[0031] (III) Beneficial effects

[0032] According to one embodiment of the present disclosure, the accuracy and / or efficiency of sensing an abnormality of a secondary battery can be improved. For example, the present disclosure can accurately and efficiently sense an abnormality of a secondary battery based on EIS.

[0033] In addition, the present disclosure can sense the abnormality of the secondary battery in the entire operating range or a part of the operating range of the secondary battery. For example, even in the rest period and constant current operating range of the secondary battery, the present disclosure can accurately sense the abnormality of the secondary battery. In other words, the present disclosure can make up for the weakness of the method of sensing the abnormality of the secondary battery based on the equivalent circuit model (ECM). BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a block diagram illustrating a configuration of a battery management system according to one embodiment of the present disclosure.

[0035] Figure 2 is a flowchart for illustrating a control method of a battery management system according to an embodiment of the present disclosure.

[0036] Figure 3a is a diagram for explaining a method of extracting a real intercept according to an embodiment of the present disclosure.

[0037] Figure 3b is a diagram for explaining a method of extracting a real intercept according to another embodiment of the present disclosure.

[0038] Figure 4 is a graph showing EIS measurement results of a plurality of cells included in a secondary battery according to one embodiment of the present disclosure.

[0039] Figure 5 is a flowchart for illustrating a control method of a battery management system according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0040] Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings. However, this is only exemplary, and the present disclosure is not limited to the specific embodiments exemplarily described.

[0041] Although the terms "first", "second" and the like are used to describe various elements, components and / or parts, these elements, components and / or parts are not limited by these terms. These terms are only used to distinguish one element, component or part from another element, component or part. Therefore, within the scope of the technical concept of the present disclosure, the first element, first component or first part mentioned below may also be the second element, second component or second part.

[0042] The terms used in this specification are intended to illustrate the embodiments, rather than to limit the present disclosure. Unless otherwise specified, in this specification, the singular includes the plural. The "comprises" and / or "made of" used in the specification indicate that the components, steps, operations and / or elements mentioned do not exclude the existence or addition of one or more other components, steps, operations and / or elements.

[0043] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this specification are used with the meanings commonly understood by ordinary technicians in the technical field to which the present disclosure belongs. In addition, unless otherwise specifically defined, the terms defined in commonly used dictionaries should not be ideally interpreted or over-interpreted.

[0044] Figure 1 is a block diagram illustrating a configuration of a battery management system according to one embodiment of the present disclosure.

[0045] Reference Figure 1 , the battery management system 100 according to one embodiment of the present disclosure can monitor and manage the secondary battery 200. According to one embodiment, the battery management system 100 can sense whether there is an abnormality in the secondary battery 200 and issue an abnormality occurrence alarm.

[0046] According to one embodiment, the secondary battery 200 may be charged. The secondary battery 200 may be a battery module including a plurality of battery cells or a battery pack including a plurality of battery modules. The secondary battery 200 may be included in a device driven by power of the secondary battery 200 (e.g., an energy storage system (ESS), an electric vehicle, etc.).

[0047] According to one embodiment, the battery management system 100 may include a memory 110 , a processor 120 , an electrochemical impedance spectroscopy (EIS) measurement module 130 , an equivalent circuit model (ECM) estimation module 140 , and an alarm module 150 .

[0048] The EIS measurement module 130 may apply a variable frequency (e.g., a sine wave) in a specified range (e.g., 1 Hz to 1 KHz) to the secondary battery 200 (e.g., each battery cell or battery module constituting the secondary battery 200) at a specified magnitude (e.g., 10 mV), receive an output signal of the secondary battery, and analyze the received output signal to measure impedance change. The impedance change of the secondary battery 200 according to the measurement result of the EIS measurement module 130 may be represented by a Nyquist plot of a rectangular coordinate system or a polar coordinate system.

[0049] The EIS measurement module 130 may measure the EIS of the secondary battery 200 (e.g., measure the EIS of each component) during operation of the device including the secondary battery 200. The EIS measurement module 130 may measure the EIS of the secondary battery 200 (e.g., measure the EIS of each component) during the entire operation interval (e.g., constant current operation interval, composite current operation interval, rest period) (e.g., Figures 2 to 4 Embodiment) or a partial operation interval (e.g., a constant current operation interval, a rest period) (e.g., Figure 5 Embodiment) performs EIS measurement.

[0050] The ECM estimation module 140 can estimate the impedance of the secondary battery 200 based on the ECM, and determine whether the secondary battery has an abnormality based on the estimation result. According to one embodiment, the ECM estimation module 140 can operate in other operating intervals (for example, except the constant current operating interval and the composite current operating interval during the rest period) in the entire operating interval. On the other hand, when only the EIS measurement result is used to determine whether the secondary battery 200 has an abnormality (for example, Figures 2 to 4 ), the ECM estimation module 140 may be omitted.

[0051] The processor 120 can control the operation of the battery management system 100. For example, the processor 120 can receive the EIS measurement result from the EIS measurement module 130, and determine whether the secondary battery 200 is abnormal based on the received EIS measurement result. When the determination result is that the secondary battery 200 is abnormal, the processor 120 can control the alarm module 150 to provide an alarm to prompt that the secondary battery 200 is abnormal. Figures 2 to 4 The specific operation of the processor 120 is described in detail.

[0052] In addition, the processor 120 can determine whether the secondary battery 200 has an abnormality by correlating the measurement results of the EIS measurement module 130 and the measurement results of the ECM estimation module 140. When the determination result is that the secondary battery 200 has an abnormality, the processor 120 can control the alarm module 150 to provide an alarm to indicate that the secondary battery 200 has an abnormality. Figure 5 The specific operation of the processor 120 is described in detail.

[0053] The memory 110 may store a program for controlling the operation of the battery management system 100. In addition, the memory 110 may store information required for controlling the operation of the battery management system 100. According to one embodiment, the memory 110 may store abnormality diagnosis software 111. The abnormality diagnosis software 111 may determine whether the secondary battery 200 has an abnormality based on the EIS measurement result. For example, the abnormality diagnosis software 111 may include a routine for extracting a real intercept of an impedance value of the secondary battery 200 (e.g., each component (e.g., a cell or a battery module) of the secondary battery 200) based on the EIS measurement result, a routine for determining whether an abnormality has occurred based on the extracted real intercept, and a routine for issuing an abnormality occurrence alarm. In addition, the abnormality diagnosis software 111 may include a routine for determining whether the secondary battery 200 has an abnormality by associating the EIS measurement result with the ECM estimation result when the battery management system 100 includes the ECM estimation module 140.

[0054] The alarm module 150 can issue an alarm to indicate that the secondary battery 200 (e.g., at least one of the components (e.g., battery cells or battery modules) of the secondary battery 200) is abnormal. The alarm module 150 can issue at least one of a visual alarm (e.g., light emitting diode (LED) light, icon display, pop-up window display, etc.), an auditory alarm (e.g., effect sound output), and a tactile alarm (e.g., vibration occurs). The alarm module 150 may include at least one of a light emitting diode, a display, a speaker, and a vibration motor.

[0055] Figure 2 is a flowchart for illustrating a control method of a battery management system according to an embodiment of the present disclosure. Figure 3a is a diagram for explaining a method of extracting a real intercept according to an embodiment of the present disclosure, Figure 3b is a diagram for explaining a method of extracting a real intercept according to another embodiment of the present disclosure, Figure 4 is a graph showing EIS measurement results of a plurality of cells included in a secondary battery according to one embodiment of the present disclosure.

[0056] Reference Figures 2 to 4According to an embodiment of the present disclosure, a control method of a battery management system (hereinafter referred to as the control method) may include a step S210 of measuring the EIS of a secondary battery. For example, the processor 120 of the battery management system 100 may measure the EIS of each component of the secondary battery 200 using the EIS measurement module 130. The EIS measurement module 130 may apply a variable frequency in a specified range (e.g., 1 Hz to 1 KHz) as an input signal to each component of the secondary battery 200 with a specified magnitude (e.g., 10 mV), and measure the output signal of each component. Here, the component may be a battery cell or a battery module. For example, if the secondary battery 200 is a battery module, the component is a battery cell, and if the secondary battery 200 is a battery pack, the component is a battery module.

[0057] According to one embodiment, the step of measuring the EIS in step S210 may be performed during operation of a device (eg, an energy storage system (ESS), an electric vehicle, etc.) including the secondary battery 200 .

[0058] The control method may include a step S220 of calculating a real intercept of an impedance value of a secondary battery (e.g., each component of the secondary battery) based on an EIS measurement result. The real intercept is a value related to an electrolyte resistance characteristic in the EIS measurement result. The processor 120 may represent the impedance value of each component in a Nyquist diagram of a rectangular coordinate system or a polar coordinate system, and calculate the real intercept of each component using the Nyquist diagram of the rectangular coordinate system or the polar coordinate system. For example, if the impedance value is represented in a Nyquist diagram of a rectangular coordinate system, the processor 120 may be as follows: Figure 3a As shown, a straight line equation connecting the first point 301 having the positive minimum value and the second point 302 having the negative maximum value in the imaginary part of the impedance value is generated, and the real intercept 303 is calculated using the generated straight line equation. Here, the straight line equation Z can be generated as shown in the following formula 1, and the real intercept 303 can be calculated by the following formula 2.

[0059] Equation of a straight line Z= <Formula 1>

[0060] Real intercept R= <Formula 2>

[0061] As another example, if the impedance values ​​are represented by a Nyquist plot in a polar coordinate system, the processor 120 may be as follows: Figure 3bAs shown, a straight line equation Z connecting the third point 311 and the fourth point 312 is generated. The generated straight line equation Z is as follows <Formula 3>, and the real intercept 313 can be calculated by Formula 4.

[0062] Equation of a straight line Z= <Formula 3>

[0063] Real intercept R= <Formula 4>

[0064] According to some embodiments, the processor may calculate the real intercept ( 303 or 313 ) using the coordinate value of the first point ( 301 or 311 ), the coordinate value of the second point ( 302 or 312 ), and a specified formula (eg, Formula 2 or Formula 4).

[0065] The control method may include a step S230 of judging whether the secondary battery has an abnormality based on the extracted real intercept. For example, the processor may calculate an index value (or representative value) representing the distribution characteristics of the extracted real intercept, and judge whether the secondary battery has an abnormality based on the calculated index value. The index value may be the difference between the maximum value and the minimum value in the real intercept, the standard deviation of the real intercept, or the Z-score of the real intercept.

[0066] Specifically, the processor may calculate the difference between the maximum value and the minimum value, and when the calculated difference is greater than (or greater than or equal to) a specified first reference value, it may be determined that the secondary battery (e.g., at least one of the components) is abnormal, and when the difference is less than or equal to (or less than) the first reference value, it may be determined that there is no abnormality. Alternatively, the processor 120 may calculate the standard deviation of the real intercept, and when the calculated standard deviation is greater than (or greater than or equal to) a specified second reference value, it may be determined that the secondary battery (e.g., at least one of the components) is abnormal, and when the standard deviation is less than or equal to (or less than) the second reference value, it may be determined that there is no abnormality. Alternatively, the processor 120 may calculate the Z score of the real intercept, and when the calculated Z score is greater than (or greater than or equal to) a specified third reference value, it may be determined that the secondary battery (e.g., at least one of the components) is abnormal, and when the Z score is less than or equal to (or less than) the third reference value, it may be determined that there is no abnormality. Here, the calculation method of the standard deviation and Z score of the real intercept is known to those skilled in the art, so detailed description will be omitted.

[0067] In other words, the processor 120 can determine whether the secondary battery 200 has an abnormality based on whether the real intercepts of the impedance values ​​of multiple components (e.g., battery cells or battery modules) included in the secondary battery 200 are distributed within a certain range (e.g., whether the real intercepts have similar values). Figure 4As shown, when the real intercepts of the first to ninth cells (cell#1 to cell#9) are distributed within a certain range, that is, have similar values, but the real intercept of the tenth cell (cell#10) deviates from the distribution alone, the processor 120 can determine that there is an abnormality in the secondary battery 200.

[0068] When the judgment result of step S230 is that there is an abnormality, the control method may enter step S240 of issuing an alarm. For example, the processor 120 may control the alarm module 150 to issue an alarm to indicate that there is an abnormality in at least one of the components (e.g., battery cells or battery modules) of the secondary battery 200. The alarm may include at least one of a visual alarm (e.g., LED lighting, icon display, pop-up window display, etc.), an auditory alarm (e.g., effect sound output), and a tactile alarm (e.g., vibration occurs).

[0069] On the contrary, when the determination result of step S230 is that there is no abnormality, the control method may end. Thereafter, the control method may periodically repeat the above steps S210 to S240.

[0070] According to one embodiment of the present disclosure, the abnormality of the secondary battery can be accurately sensed using the EIS measurement result. In addition, one embodiment of the present disclosure can accurately sense the abnormality of the secondary battery in the entire operating range of the secondary battery. That is, according to one embodiment of the present disclosure, the accuracy and / or efficiency of sensing the abnormality of the secondary battery can be improved.

[0071] According to an embodiment of the present disclosure, it is possible to determine whether a secondary battery has an abnormality based on a real intercept (corresponding to the electrolyte resistance characteristic in the EIS measurement result) related to multiple components constituting the secondary battery. The present disclosure can determine whether an abnormality exists by reflecting the difference in states (e.g., temperature, degree of deterioration, etc.) between multiple components included in the secondary battery 200. Therefore, the present disclosure can effectively determine whether the secondary battery 200 has an abnormality.

[0072] Figure 5 is a flowchart for illustrating a control method of a battery management system according to another embodiment of the present disclosure.

[0073] Reference Figure 5 According to another embodiment of the present disclosure, a control method of a battery management system includes a step S505 of confirming whether it is a designated operation interval. The designated operation interval may include an interval in which it is difficult to estimate impedance based on an equivalent circuit model (ECM) in the entire operation interval of a secondary battery included in an electric vehicle and an energy storage system, etc. For example, the designated operation interval may include a rest period and a constant current operation interval in the operation interval of the secondary battery.

[0074] When the confirmation result of step S505 is the specified operation range, the control method may enter step S510. Thereafter, the control method may execute steps S520, S530, and S540. Here, steps S510 to S540 are similar to Figure 2 Steps S210 to S240 are similar, so detailed description will be omitted.

[0075] On the contrary, when the confirmation result of step S505 is not the specified operating range, the control method may enter step S525 of estimating the impedance of the secondary battery based on an equivalent circuit model (ECM). Thereafter, the control method may execute step S535 of determining whether the secondary battery has an abnormality based on the estimation result based on the ECM. When the judgment result of step S535 is that an abnormality exists, the control method may enter step S540. On the contrary, when the judgment result of step S535 is that there is no abnormality, the control method may end. Thereafter, the processor 120 may periodically repeat the above steps S505 to S540.

[0076] The control method of the battery management system according to another embodiment of the present disclosure can determine whether the secondary battery has an abnormality by correlating the EIS measurement and the measurement based on the equivalent circuit model. That is, another embodiment of the present disclosure can make up for the weakness of the method of sensing the abnormality of the secondary battery based on the equivalent circuit model, which is difficult to estimate the impedance during the rest period and the constant current operation interval.

[0077] The above content is only an example of applying the principles of the present disclosure, and other configurations may also be included without departing from the scope of the present invention.

Claims

1. A battery management system, comprising: An alarm module, which provides an alarm in a specified manner; The electrochemical impedance spectroscopy measurement module is the EIS measurement module, which measures the electrochemical impedance spectroscopy of the secondary battery, namely, EIS; as well as The processor receives the EIS measurement result from the EIS measurement module, calculates the real intercept of the impedance value of the secondary battery based on the received EIS measurement result, and determines whether the secondary battery has an abnormality based on the calculated real intercept. When the judgment result is that the secondary battery has an abnormality, the processor controls the alarm module to provide an alarm to prompt that the secondary battery has an abnormality.

2. The battery management system according to claim 1, wherein: The EIS measurement module measures the EIS of each battery cell or each battery module.

3. The battery management system according to claim 2, wherein: The processor represents the impedance value of each of the battery cells or each of the battery modules as a Nyquist diagram of a rectangular coordinate system or a polar coordinate system, and calculates a real intercept of each of the battery cells or each of the battery modules using the Nyquist diagram of the rectangular coordinate system or the polar coordinate system.

4. The battery management system according to claim 3, wherein: The processor selects a first point having a positive minimum value and a second point having a negative maximum value in the imaginary part of the impedance value, and calculates the real intercept using a coordinate value of the first point, a coordinate value of the second point, and a specified formula.

5. The battery management system according to any one of claims 1 to 3, wherein: The processor calculates a difference between a maximum value and a minimum value of the calculated real intercepts, and determines that an abnormality occurs in the secondary battery when the calculated difference is greater than a specified first reference value.

6. The battery management system according to any one of claims 1 to 3, wherein: The processor calculates a standard deviation of the calculated real intercept, and determines that an abnormality occurs in the secondary battery when the calculated standard deviation is greater than a specified second reference value.

7. The battery management system according to any one of claims 1 to 3, wherein: The processor calculates a Z score of the calculated real intercept, and determines that an abnormality occurs in the secondary battery when the calculated Z score is greater than a specified third reference value.

8. The battery management system according to any one of claims 1 to 3, wherein: The processor controls the EIS measurement module to measure the EIS during operation of a device including the secondary battery.

9. The battery management system according to any one of claims 1 to 3, wherein: The processor confirms whether it is a designated operation interval, When the confirmation result is the specified operation interval, the processor determines whether the secondary battery has an abnormality based on the calculated real intercept, When the confirmation result is an operation range other than the specified operation range, the processor estimates the impedance of the secondary battery using an equivalent circuit model estimation module, and determines whether the secondary battery has an abnormality using the estimation result based on the equivalent circuit model.

10. The battery management system according to any one of claims 1 to 3, wherein: The EIS measurement module applies a variable frequency in a specified range as an input signal to the secondary battery at a specified current magnitude, and measures a voltage of the secondary battery.

11. A control method for a battery management system, comprising: The step of measuring the EIS of the secondary battery by an electrochemical impedance spectroscopy measurement module, i.e., an EIS measurement module; A step of calculating a real intercept of the impedance value of the secondary battery based on the measured EIS; a step of judging whether the secondary battery has an abnormality based on the calculated real intercept; as well as When the determination result is that the secondary battery is abnormal, the alarm module is controlled to provide an alarm to prompt that the secondary battery is abnormal.

12. The control method of the battery management system according to claim 11, wherein: The step of calculating the real intercept comprises: The step of expressing the impedance value of the secondary battery in a Nyquist diagram of a rectangular coordinate system or a polar coordinate system; and The step of calculating the real intercept of the impedance value using the Nyquist diagram of the rectangular coordinate system or the polar coordinate system.

13. The control method of the battery management system according to claim 12, wherein: The step of calculating the real intercept comprises: The step of selecting a first point having a positive minimum value and a second point having a negative maximum value in the imaginary part of the impedance value; and The step of calculating the real intercept using the coordinate value of the first point, the coordinate value of the second point and a specified formula.

14. The control method of a battery management system according to any one of claims 11 to 13, wherein: The step of determining whether the secondary battery is abnormal comprises: a step of calculating the difference between the maximum value and the minimum value of the calculated real intercept; and The step of determining that an abnormality occurs in the secondary battery when the calculated difference is greater than a first reference value.

15. The control method of a battery management system according to any one of claims 11 to 13, wherein: The step of determining whether the secondary battery is abnormal comprises: a step of calculating a standard deviation of said calculated real intercept; and The step of determining that an abnormality occurs in the secondary battery when the calculated standard deviation is greater than a specified second reference value.

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