Battery unit monitoring method and device

Abstract

The battery monitoring method may include measuring an open circuit voltage (OCV) of each of the battery cells in a first idle period, estimating a capacity of each of the battery cells using the OCV of each of the battery cells measured in the first idle period, measuring the OCV of each of the battery cells in a second idle period subsequent to the first idle period, and estimating a capacity of each of the battery cells using the OCV of each of the battery cells measured in the second idle period. Estimating a capacity of each of the battery cells using the OCV of each of the battery cells measured in the second idle period, and detecting an internal short-circuit battery based on the capacity of each of the battery cells in the first idle period and the capacity of each of the battery cells in the second idle period. The invention further discloses a battery monitoring device.

Description

Technical Field

[0001] The present disclosure relates to a battery cell monitoring method and device. Background Art

[0002] Because an energy storage system (ESS) includes battery cells, if a specific battery ignites due to an internal short circuit, it may spread to adjacent batteries, and therefore, the entire system is likely to burn out. Therefore, it is very important to detect an internal short circuit in a battery as early as possible so that the user can stop the operation of the system and respond safely before the battery ignites.

[0003] If an internal short circuit occurs in a battery, the capacity of the battery continues to decrease, and the internal short circuit can usually be determined by estimating the amount of battery capacity reduction. However, in order to estimate the battery capacity reduction, the charge / discharge capacity of the battery must be accurately calculated, and accurate calculation of the charge / discharge capacity of the battery may be difficult due to various factors such as the accuracy of the current sensor, temperature and efficiency of the charge / discharge rate, current consumption of the battery management system, the self-discharge amount of the battery, and battery balancing. Summary of the invention

[0004] An embodiment includes a method for monitoring battery cells in a battery module in a battery monitoring device. The method includes measuring an open circuit voltage (OCV) of each of the battery cells during a first idle period, estimating a capacity of each of the plurality of batteries using the OCV of each of the plurality of batteries measured during the first idle period, measuring the OCV of each of the battery cells during a second idle period after the first idle period, estimating a capacity of each of the battery cells using the OCV of each of the battery cells measured during the second idle period, and detecting an internal short-circuited battery based on the capacity of each of the battery cells during the first idle period and the capacity of each of the battery cells during the second idle period.

[0005] Detecting an internal short-circuited cell may include calculating a capacity reduction of each of the battery cells based on a difference between a capacity of each of the battery cells in a first idle period and a capacity of each of the battery cells in a second idle period, and determining whether the first battery is an internal short-circuited battery by comparing the capacity reduction of a first battery in the battery cells with an average capacity reduction of remaining batteries in the battery cells other than the first battery.

[0006] Determining whether the first battery is an internal short-circuited battery may include determining the first battery to be an internal short-circuited battery if a difference between a capacity reduction amount of the first battery and an average capacity reduction amount of remaining batteries other than the first battery is greater than a predetermined threshold.

[0007] The method may also include calculating the consumed capacity of each battery cell during the discharge period and the charging period, wherein calculating the capacity reduction of each battery cell may include calculating the capacity reduction of each battery cell, which reflects the consumed capacity of each battery cell calculated during the discharge period and the charging period in the difference between the capacity of each battery cell estimated during the first idle period and the second idle period.

[0008] Calculating the consumption capacity of each battery cell may include connecting the battery module to a load during a discharge period and connecting the battery module to a charging device during a charge period.

[0009] Measuring the OCV of each of the battery cells may include blocking current supply to the battery module.

[0010] An embodiment includes a battery monitoring device that manages battery cells by setting a rest period, a discharge period, and a charge period as one operation cycle, the battery monitoring device including an open circuit voltage (OCV) calculator that measures the OCV of each of the battery cells during an idle period of each operation cycle and estimates the capacity of each of the battery cells using the OCV of each of the battery cells, a consumption capacity calculator that calculates the consumption capacity of each battery cell during a discharge period and a charge period of each operation cycle, and a short-circuited battery detector that calculates a capacity reduction amount of each battery cell based on the capacity of each battery cell and the consumption capacity of each battery cell, and detects an internal short-circuited battery based on the capacity reduction amount of each battery cell.

[0011] The short-circuit battery detector can calculate the capacity reduction of each battery cell by reflecting the consumed capacity of each battery cell calculated during the discharge period and the charging period of the first operating cycle in the difference between the capacity of each battery cell estimated during the idle period of the first operating cycle and the capacity of each battery cell during the idle period of the second operating cycle immediately before the first operating cycle.

[0012] The short-circuited cell detector may detect whether the first battery is an internal short-circuited battery by comparing a capacity reduction amount of a first battery in the battery cells with an average capacity reduction amount of remaining batteries in the battery cells except the first battery.

[0013] The short-circuited battery detector may determine the first battery as an internal short-circuited battery if a difference between a capacity reduction amount of the first battery and an average capacity reduction amount of the remaining batteries except the first battery is greater than a predetermined threshold value.

[0014] The battery monitoring apparatus may further include a switch controller which disconnects a battery module including the battery cells from an external device during an idle period and connects the battery module to the external device during a discharge period and a charge period. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Features will become apparent to those skilled in the art by describing in detail exemplary embodiments with reference to the accompanying drawings, in which:

[0016] Figure 1 is a diagram illustrating a battery pack according to one or more embodiments.

[0017] Figure 2 is a diagram illustrating a method for operating a battery pack according to one or more embodiments.

[0018] Figure 3 is a flow chart illustrating a battery monitoring method according to one or more embodiments.

[0019] Figure 4 is a graph illustrating capacities of a normal battery and an internal short-circuited battery according to one or more embodiments.

[0020] Figure 5 According to one or more embodiments Figure 4 An enlarged view of portion A of the graph shown in FIG.

[0021] Figure 6 is a diagram illustrating a battery monitoring device according to one or more embodiments.

[0022] Figure 7 is a diagram illustrating a battery monitoring device according to one or more other embodiments. DETAILED DESCRIPTION

[0023] Example embodiments will now be described more fully below with reference to the accompanying drawings. In the accompanying drawings, the sizes of layers and regions may be exaggerated for clarity of illustration. It should also be understood that when a layer or element is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or there may also be intervening layers. In addition, it should be understood that when a layer is referred to as being "below" another layer, it can be directly below, and there may also be one or more intervening layers. In addition, it should also be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there may also be one or more intervening layers. The same reference numerals refer to the same elements throughout.

[0024] The example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the exemplary embodiments to those skilled in the art. The drawings and description are to be regarded as illustrative in nature and not restrictive. In the flowcharts described in this specification with reference to the drawings, the order of operations may be changed, several operations may be combined, some operations may be divided, and certain operations may not be performed.

[0025] Throughout the specification and claims, unless explicitly stated otherwise, if a part is referred to as “comprising” a certain element, it may mean that it may further include other elements rather than excluding the other elements.

[0026] In addition, unless an explicit expression such as "a" or "single" is used, expressions described in the singular may be interpreted in the singular or in the plural.

[0027] In addition, terms including ordinal numbers (such as first, second, etc.) can be used to describe various elements, but the elements are not limited by the terms. The above terms are only used for the purpose of distinguishing one element from another element. For example, without departing from the scope of the present disclosure, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element.

[0028] Furthermore, if it is mentioned that one component is “connected” to another component, it includes not only the case where the two components are “directly connected” but also the case where the two components are “indirectly or non-contactly connected” to another component interposed therebetween, or the case where the two components are “electrically connected”. On the other hand, if an element is said to be “directly connected” to another element, it should be understood that there are no other elements in between.

[0029] Figure 1 is a diagram illustrating a battery pack according to one or more embodiments.

[0030] refer to Figure 1 The battery pack 1 may include at least one battery module 10, a switch 20, and a battery monitoring device 30. The battery pack 1 may also include terminals T+ and T-.

[0031] The battery pack 1 may be connected to an external charging device or a load through terminals T+ and T−, and may be charged by the charging device and discharged by the load.

[0032] At least one battery module 10 may include batteries electrically connected in series and / or in parallel to each other, such as battery cells 11, 12, 13, and 14. Figure 1 In the figure, for the convenience of explanation, only four battery cells 11, 12, 13 and 14 are shown. There may be fewer or more batteries.

[0033] The switch 20 may control a current path during charging and discharging of the battery module 10. Closing and opening of the switch 20 may be controlled according to a switch control signal SCS transmitted from the battery monitoring device 30.

[0034] The battery monitoring device 30 may control and manage the overall operation of the battery pack 1. The battery monitoring device 30 may monitor the overall state of the battery module 10 and the batteries 11, 12, 13, and 14 included in the battery module 10, and may perform various control functions to adjust the state of the battery module 10 and the batteries 11, 12, 13, and 14 included in the battery module 10. In an exemplary embodiment, the battery monitoring device 30 may control the charge / discharge current of the battery module 10 based on the battery voltage and battery current of the battery cells 11, 12, 13, and 14 in the embodiment, and may perform a battery balancing operation on the batteries 11, 12, 13, and 14.

[0035] The battery monitoring device 30 may measure the voltages of the battery cells 11, 12, 13, and 14 or receive the voltages of the battery cells 11, 12, 13, and 14. The battery monitoring device 30 may measure the battery current or may receive the battery current measured by the current sensor.

[0036] The battery monitoring device 30 may be, for example, a battery management system (BMS).

[0037] According to an embodiment, the battery monitoring device 30 can monitor the battery cells 11, 12, 13, and 14 and detect an internal short-circuited battery. The battery monitoring device 30 can calculate the capacity reduction amount of each battery 11, 12, 13, and 14, and can compare the capacity reduction amount of each battery 11, 12, 13, and 14 with the capacity reduction amount of the remaining batteries except the corresponding battery, and can detect the internal short-circuited battery according to the comparison result.

[0038] Figure 2 is a diagram illustrating a method for operating a battery pack according to one or more embodiments.

[0039] refer to Figure 2 , the battery pack 1 can be operated by setting the discharge period, the charge period, and the rest period as one operation cycle. The rest period may be a period for stabilizing the battery pack 1. The battery pack 1 may perform the discharge operation, the charge operation, and the rest operation according to the discharge period, the charge period, and the rest period of the operation cycle.

[0040] In the discharge period, the battery monitoring device 30 may set the switch 20 to an on state to connect the battery module 10 to the load. The battery module 10 may be discharged according to load use.

[0041] During the charging period, the battery monitoring device 30 may set the switch 20 to an on state to connect the battery module 10 to the charging device. The battery module 10 may be charged by the charging device.

[0042] In the idle period, the battery monitoring device 30 may set the switch 20 to an off state and stabilize the voltage of the battery module 10. In the idle period, no current flows through the battery module 10.

[0043] The battery monitoring device 30 may monitor the states of the batteries 11, 12, 13, and 14 during the discharge period and the charge period, and may control the discharge and charge of the batteries 11, 12, 13, and 14 according to the states of the batteries 11, 12, 13, and 14. In one or more embodiments, the battery monitoring device 30 may maintain the voltages of the batteries 11, 12, 13, and 14 by cell balancing.

[0044] Figure 3 is a flow chart illustrating a battery monitoring method according to one or more embodiments.

[0045] refer to Figure 3 , the battery pack 1 can perform a discharge operation, a charge operation, and a rest operation according to an operation cycle.

[0046] The battery monitoring device 30 may measure the open circuit voltage (OCV) of each battery 11, 12, 13, and 14 of the battery module 10 during an idle period (S310). The battery monitoring device 30 may estimate the capacity of each battery 11, 12, 13, and 14 using the OCV of each battery 11, 12, 13, and 14, and may store the capacity of each battery 11, 12, 13, and 14 (S320).

[0047] The battery monitoring device 30 may estimate the capacity of each battery 11, 12, 13, and 14 based on the OCV of each battery 11, 12, 13, and 14 using an OCV table. The OCV table may be a table storing the capacity of each OCV. In the OCV table, the OCV may be subdivided into set voltage units. The battery monitoring device 30 may check the capacity corresponding to the OCV of each battery 11, 12, 13, and 14 in the OCV table. If the OCV of each battery 11, 12, 13, and 14 is not in the OCV table, an interpolation method may be used to estimate the capacity of each battery 11, 12, 13, and 14 based on two or more OCV values ​​in the OCV table and the capacities corresponding to the two or more OCV values.

[0048] According to an example embodiment, the battery monitoring device 30 can reflect the current SOH (state of health) of each battery 11, 12, 13 and 14 in the capacity of each battery 11, 12, 13 and 14 estimated using the OCV table, and can more accurately estimate the capacity of each battery 11, 12, 13 and 14.

[0049] The battery monitoring device 30 may calculate the consumption capacity of each battery 11, 12, 13, and 14 based on the voltage of each battery 11, 12, 13, and 14 in the discharge period and the charge period, and may store the consumption capacity of each battery 11, 12, 13, and 14 (S330).

[0050] The battery monitoring device 30 may calculate the capacity reduction amount of each battery 11, 12, 13, and 14 based on the capacity of each battery 11, 12, 13, and 14 (S340). The battery monitoring device 30 may calculate the capacity reduction amount of each battery 11, 12, 13, and 14 using the difference between the capacity of each battery 11, 12, 13, and 14 calculated in the idle period of the current cycle and the capacity of each battery 11, 12, 13, and 14 calculated in the idle period of the previous cycle (S340). In addition, the battery monitoring device 30 may calculate the capacity reduction amount of each battery 11, 12, 13, and 14 by reflecting the consumed capacity of each battery 11, 12, 13, and 14 in the difference between the capacity of each battery 11, 12, 13, and 14 calculated in the idle period of the current cycle and the capacity of each battery 11, 12, 13, and 14 calculated in the idle period of the previous cycle (S340).

[0051] The battery monitoring device 30 may compare the capacity reduction amount of each battery 11, 12, 13 and 14 with the average capacity reduction amount of the remaining batteries except the corresponding battery 11, 12, 13 and 14, and may determine whether each battery 11, 12, 13 and 14 is an internal short-circuited battery.

[0052] More specifically, the battery monitoring device 30 may calculate a difference between a capacity reduction amount of each battery 11, 12, 13, and 14 and an average capacity reduction amount of the remaining batteries excluding the corresponding battery 11, 12, 13, and 14 (S350), and may compare the difference calculated for each battery 11, 12, 13, and 14 with a predetermined threshold value (S360).

[0053] If the calculated difference of the battery is greater than the predetermined threshold, the battery monitoring device 30 may determine that the battery is an internal short-circuited battery (S370). In an example embodiment, if the calculated difference of the battery is greater than the predetermined threshold, it may mean that the capacity of the battery has decreased by more than the predetermined threshold.

[0054] If the calculated difference of the battery is less than the predetermined threshold, the battery monitoring device 30 may determine that the battery is a normal battery (S380).

[0055] In an exemplary embodiment, it can be assumed that the capacities of batteries 11, 12, 13 and 14 calculated in the idle period of the previous cycle are 95Ah, 100Ah, 100Ah and 100Ah, respectively, and the capacities of batteries 11, 12, 13 and 14 calculated in the idle period of the current cycle are 93Ah, 101Ah, 101Ah and 100Ah, respectively, and the capacities of batteries 11, 12, 13 and 14 consumed by battery balancing in the discharge period and the charging period of the current cycle are -3Ah, 0Ah, 0Ah and 0Ah, respectively. Then, the capacity reduction amount of battery 11 may be -4Ah (=93Ah-95Ah-3Ah), the capacity reduction amount of battery 12 may be 1Ah (=101Ah-100Ah-0Ah), and the capacity reduction amount of battery 13 may be 1Ah (=101Ah-100Ah-0Ah), and the capacity reduction amount of battery 14 may be 0Ah (=100Ah-100Ah-0Ah). In some embodiments, if the capacity reduction amount has a negative value (-), it may mean that the capacity has been reduced.

[0056] In order to determine whether the battery 11 is a short-circuited battery, the difference between the capacity reduction of the battery 11 and the average capacity reduction of the remaining batteries 12, 13, and 14 may be calculated. In an embodiment, it is assumed that the predetermined threshold used for comparison to determine whether the battery is an internal short-circuited battery may be set to -3Ah. Since the capacity reduction of the battery 11 is -4Ah, and the average capacity reduction of the remaining batteries 12, 13, and 14 is 2 / 3Ah, and the capacity reduction of the battery 11 has decreased to a value greater than the average capacity reduction of the remaining batteries 12, 13, and 14 by -3Ah, the battery 11 may be determined to be an internal short-circuited battery.

[0057] Figure 4 is a graph showing the capacity of a normal battery and an internally short-circuited battery, and Figure 5 yes Figure 4 An enlarged view of portion A is shown in FIG.

[0058] refer to Figure 4 and Figure 5 , the capacity of the internal short-circuited battery 11 may be continuously reduced compared with the normal batteries 12, 13, and 14. Therefore, the internal short-circuited battery can be detected by estimating the capacity reduction amount of the battery.

[0059] In some embodiments, in order to estimate the capacity reduction of the battery, the charge / discharge capacity of the battery must be accurately calculated, and accurate calculation of the charge / discharge capacity of the battery may be difficult due to various factors such as the accuracy of the current sensor, the efficiency and charge / discharge rate affected by temperature, the self-discharge of the battery, and the current consumption according to battery balancing.

[0060] In other embodiments, the battery monitoring device 30 may calculate the capacity reduction amount of the battery based on the difference between the capacity of the battery estimated by OCV in the previous idle period and the capacity of the battery estimated by OCV in the current idle period.

[0061] In this way, by estimating the capacity of the battery using the OCV measured during the idle period, the accuracy of the capacity estimation can be improved because capacity calculation errors caused by factors such as the accuracy of the current sensor, efficiency and charge / discharge rate affected by temperature, self-discharge of the battery, and current consumption based on battery balancing can be eliminated.

[0062] In one or more embodiments, another method for determining an internal short-circuited battery may be a method of comparing the voltage between batteries. In the method of comparing the voltage between batteries, the voltage-capacity value of each voltage segment may be different, so the capacity standard corresponding to the threshold of each voltage segment may be different, and therefore, the short-circuit resistance detected for each voltage segment may vary. This means that the capacity reduction amount may vary according to the voltage segment of the detection voltage, that is, this may affect the detection accuracy of the internal short-circuited battery.

[0063] In other embodiments, the method of estimating the capacity of a battery using the OCV measured in an idle period does not require comparing the voltage between batteries, and thus can detect an internal shorted battery more accurately than the method of comparing the voltage between batteries.

[0064] Figure 6 is a diagram showing a battery monitoring device according to an embodiment.

[0065] refer to Figure 6 The battery monitoring device 30 may include an OCV calculator 32, a consumption capacity calculator 34, and a short-circuit battery detector 36. The battery monitoring device 30 may further include a storage portion 38. In addition, the battery monitoring device 30 may further include a switch controller 39.

[0066] The OCV calculator 32 may measure the OCV of each of the batteries 11, 12, 13, and 14 in each idle period, and may estimate the capacity of each of the batteries 11, 12, 13, and 14 using the measured OCV of each of the batteries 11, 12, 13, and 14. The capacity of each of the batteries 11, 12, 13, and 14 measured in each idle period may be stored in the storage part 38.

[0067] The consumption capacity calculator 34 may calculate the consumption capacity of each battery 11, 12, 13, and 14 in the discharge period and the charge period. The consumption capacity of each battery 11, 12, 13, and 14 calculated in the discharge period and the charge period may be stored in the storage part 38.

[0068] The short-circuit battery detector 36 may calculate the difference between the capacity of each battery 11, 12, 13, and 14 calculated in two idle periods adjacent in time. The short-circuit battery detector 36 may calculate the difference between the capacity of each battery 11, 12, 13, and 14 calculated in the idle period of the t-th cycle and the capacity of each battery 11, 12, 13, and 14 calculated in the idle period of the (t-1)-th cycle. The short-circuit battery detector 36 may calculate the capacity reduction amount of each battery 11, 12, 13, and 14 in the t-th cycle by reflecting the consumed capacity of each battery 11, 12, 13, and 14 calculated in the discharge period and the charge period of the t-th cycle in the calculated difference of each battery 11, 12, 13, and 14. The short-circuited battery detector 36 can calculate the difference between the capacity reduction of each battery 11, 12, 13 and 14 in the tth cycle and the average capacity reduction of the remaining batteries except the corresponding battery, and can determine the battery whose calculated difference is greater than or equal to a predetermined threshold as an internal short-circuited battery.

[0069] The switch controller 39 may output a switch control signal SCS to the switch 20 to control the opening or closing of the switch 20 in the rest period, the discharge period, and the charging period. The switch controller 39 may output a switch control signal SCS that controls the opening of the switch 20 in the idle period. The switch controller 39 may output a switch control signal SCS that controls the closing of the switch 20 in the discharge period and the charging period.

[0070] Figure 7 is a diagram illustrating a battery monitoring device according to one or more other embodiments.

[0071] refer to Figure 7 The battery monitoring apparatus 700 may represent a computing device that implements the above-mentioned battery monitoring method.

[0072] The battery monitoring apparatus 700 may include at least one of a processor 710, a memory 720, an input interface device 730, an output interface device 740, and a storage device 750. Each component may be connected and communicate with each other through a bus 760. In addition, each component may be connected through a separate interface or a separate bus centered on the processor 710 instead of the common bus 760.

[0073] The processor 710 may be implemented as various types, such as an application processor (AP), a central processing unit (CPU), a graphics processing unit (GPU), etc., and may be any semiconductor device that executes commands stored in the memory 720 or the storage device 750. The processor 710 may execute program commands stored in at least one of the memory 720 and the storage device 750. The processor 710 may be configured to implement the above-mentioned Figures 1 to 6 Describes the functions and methods.

[0074] The memory 720 and the storage device 750 may include various types of volatile or non-volatile storage media. For example, the memory 720 may include a read-only memory (ROM) 721 and a random access memory (RAM) 722. In an embodiment, the memory 720 may be located inside or outside the processor 710, and the memory 720 may be connected to the processor 710 by various known means.

[0075] The input interface device 730 may be configured to provide data to the processor 710 .

[0076] The output interface device 740 may be configured to output data from the processor 710 .

[0077] In one or more embodiments, an internal shorted battery may be detected by calculating the capacity of the battery using an open circuit voltage calculated during an idle period.

[0078] Although various embodiments of the present invention have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present disclosure defined in the appended claims are also included in the present disclosure.

Claims

1. A method for monitoring a battery cell in a battery module in a battery monitoring device, the method comprising: measuring an open circuit voltage (OCV) of each of the battery cells during a first idle period; estimating a capacity of each of the battery cells using the OCV of each of the battery cells measured during the first idle period; measuring the OCV of each of the battery cells during a second idle period after the first idle period; estimating a capacity of each of the battery cells using the OCV of each of the battery cells measured during the second idle period; as well as An internal short-circuited battery is detected based on a capacity of each of the battery cells in the first idle period and a capacity of each of the battery cells in the second idle period.

2. The method according to claim 1, wherein: Detection of internal shorted batteries includes: calculating a capacity reduction amount of each of the battery cells based on a difference between a capacity of each of the battery cells in the first idle period and a capacity of each of the battery cells in the second idle period; and Whether the first battery is the internal short-circuited battery is determined by comparing a capacity reduction amount of a first battery in the battery cells with an average capacity reduction amount of remaining batteries in the battery cells except the first battery.

3. The method according to claim 2, wherein Determining whether the first battery is the internal short-circuited battery includes: If a difference between a capacity reduction amount of the first battery and an average capacity reduction amount of remaining batteries other than the first battery is greater than a predetermined threshold, the first battery is determined to be the internal short-circuited battery.

4. The method according to claim 2, further comprising: calculating a consumed capacity of each of the battery cells in a discharge period and a charge period, Wherein, calculating the capacity reduction amount of each battery cell includes calculating the capacity reduction amount of each battery cell by reflecting the consumption capacity of each battery cell calculated in the discharge period and the charge period in the difference between the capacity of each battery cell estimated in the first idle period and the second idle period.

5. The method according to claim 4, wherein: Calculating the consumed capacity of each of the battery cells includes: connecting the battery module to a load during the discharge period; and The battery module is connected to a charging device during the charging period. The method of claim 4 , wherein measuring the OCV of each of the battery cells comprises blocking a current supply to the battery module.

7. A battery monitoring device that manages a battery cell by setting a rest period, a discharge period, and a charge period as one operation cycle, the battery monitoring device comprising: an open circuit voltage (OCV) calculator that measures the OCV of each of the battery cells during an idle period of each operation cycle and estimates the capacity of each of the battery cells using the OCV of each of the battery cells; a consumption capacity calculator that calculates the consumption capacity of each battery cell during a discharge period and a charge period of each operation cycle; as well as A short-circuited battery detector calculates a capacity reduction amount of each of the battery cells based on the capacity of each of the battery cells and a consumed capacity of each of the battery cells, and detects an internal short-circuited battery based on the capacity reduction amount of each of the battery cells.

8. The battery monitoring device according to claim 7, wherein The short-circuited battery detector calculates the capacity reduction of each battery cell by reflecting the consumed capacity of each battery cell calculated during the discharge period and the charging period of the first operating cycle in the difference between the capacity of each battery cell estimated in the idle period of the first operating cycle and the capacity of each battery cell in the idle period of the second operating cycle immediately before the first operating cycle.

9. The battery monitoring device according to claim 7, wherein The short-circuited battery detector detects whether a first battery in the battery cell is an internal short-circuited battery by comparing a capacity reduction amount of the first battery in the battery cell with an average capacity reduction amount of remaining batteries in the battery cell except the first battery.

10. The battery monitoring device according to claim 7, wherein The short-circuited battery cell detector determines the first battery as an internal short-circuited battery if a difference between a capacity reduction amount of the first battery and an average capacity reduction amount of the remaining batteries except the first battery is greater than a predetermined threshold value.

11. The battery monitoring device according to claim 7, further comprising: A switch controller disconnects a battery module including the battery cells from an external device during the idle period and connects the battery module to the external device during the discharge period and the charge period.

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