Battery diagnostic device and method for detecting leakage current

Abstract

A battery diagnostic device according to an embodiment of the present invention is a battery diagnostic device located in a battery system including one or more batteries, and includes at least one processor; and a memory for storing at least one instruction executed by the at least one processor. The at least one instruction may include an instruction for collecting state of charge information of the battery in a standby mode state of the battery system; an instruction for calculating a power change amount of the battery during a standby mode maintenance period based on the collected state of charge information and a state of pre-stored initial charge information; and an instruction for comparing the calculated power change amount with an expected discharge power amount of the battery and determining whether a leakage current occurs in the battery system based on a comparison result.

Description

[Technical Field]

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2022-0130145 filed with the Korean Intellectual Property Office on October 12, 2022, and Korean Patent Application No. 10-2023-0068061 filed with the Korean Intellectual Property Office on May 26, 2023, and all of the contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery diagnostic device and method, and more particularly to a battery diagnostic device and method for detecting whether or not leakage current is occurring in a battery system based on the amount of power change in the battery system when it is in standby mode. [Background technology]

[0003] Secondary batteries are batteries that can be reused by recharging after discharge and can be used as energy sources for small devices such as mobile phones, tablet PCs, and vacuum cleaners, as well as medium- to large-sized devices such as automobiles and smart grid energy storage systems (ESS).

[0004] Secondary batteries are applied to systems in the form of assemblies such as battery modules in which multiple battery cells are connected in series and parallel, or battery packs in which battery modules are connected in series and parallel, depending on the requirements of the system. In the case of medium to large devices such as electric vehicles, large-capacity battery systems in which multiple battery packs are connected in parallel can be applied to meet the required capacity of the device.

[0005] For stable operation of a battery system, the electrical components in the battery system must be well-insulated. If the insulation is not maintained, leakage current may occur, causing malfunctions in the battery system and devices or even a fire.

[0006] The leakage current detection technology mainly uses a leakage current detection sensor placed at a specific position to determine whether leakage current is occurring in a battery system.

[0007] However, if a small current leaks to the power conversion system (PCS) side in a battery system or if leakage current occurs due to poor grounding within the battery assembly, the above-mentioned conventional techniques cannot detect the leakage current.

[0008] To solve these problems of the conventional technology, there is a need for an appropriate technology that can accurately detect whether or not leakage current is occurring in a battery system without using a leakage current detection sensor. Summary of the Invention [Problem to be solved by the invention]

[0009] SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a battery diagnostic device that can detect whether or not leakage current occurs in a battery system without using a leakage current detection sensor.

[0010] Another object of the present invention to solve the above problems is to provide a battery diagnostic method using such a battery diagnostic device. [Means for solving the problem]

[0011] To achieve the above object, one embodiment of the present invention provides a battery diagnostic device located in a battery system including one or more batteries, and may include at least one processor; and a memory for storing at least one instruction executed through the at least one processor.

[0012] The at least one instruction may include an instruction to collect charging information status of the battery in a standby mode state of the battery system; an instruction to calculate a power change amount of the battery during a standby mode maintenance period based on the collected charging information status and a pre-stored initial charging information status; and an instruction to compare the calculated power change amount with an expected discharge power amount of the battery and determine whether leakage current is occurring in the battery system based on the comparison result.

[0013] The command to collect the state of charge information of the battery may include a command to collect an open circuit voltage value (Vocv) measured after a predefined time has elapsed when the battery system is switched to a standby mode; a command to determine a state of charge value (SOC) based on the open circuit voltage value (Vocv); and a command to store the determined state of charge value (SOC) as an initial state of charge value (SOC_init).

[0014] The instructions for collecting state of charge information of the battery may include instructions for determining a state of charge (SOC) value of the battery at predefined intervals while the battery system is in standby mode.

[0015] The command to calculate the power change amount of the battery may include a command to calculate the power change amount based on a difference value (ΔSOC) between a pre-stored initial state of charge value (SOC_init) and the calculated state of charge value (SOC).

[0016] The expected discharge power amount can be defined based on at least one of: a self-discharge power amount of the battery; and an internal supply power amount provided by the battery to a power demanding device located inside the battery system.

[0017] The expected discharge power amount can be defined as a value obtained by multiplying the sum of the self-discharge power amount and the power amount supplied by the battery to a battery management system (BMS) by a predefined weighting coefficient.

[0018] The command to determine whether leakage current has occurred in the battery system may include a command to determine that leakage current has occurred in the battery if the calculated power change amount exceeds the expected discharge power amount.

[0019] The at least one instruction may further include an instruction to collect temperature values ​​of the battery when the battery system is in standby mode; and an instruction to calculate a temperature change amount of the battery based on the collected temperature values.

[0020] The command to determine whether leakage current has occurred in the battery system may include a command to determine that leakage current has occurred in the battery if the calculated power change amount exceeds the expected discharge power amount and the calculated temperature change amount exceeds a predefined reference temperature change amount.

[0021] The at least one command may further include a command to determine whether the battery is performing a balancing control operation, wherein the command to determine whether leakage current is occurring in the battery system may include a command to determine that leakage current is occurring in the battery when a first condition that the calculated power change amount exceeds the expected discharge power amount and a third condition that the battery is not performing a balancing control operation are satisfied.

[0022] The instruction to determine whether leakage current occurs in the battery system may include an instruction to detect one or more batteries in which leakage current occurs among a plurality of batteries included in the battery system.

[0023] To achieve the above-mentioned another object, a battery diagnostic method according to one embodiment of the present invention is a battery diagnostic method using a battery diagnostic device located in a battery system including one or more batteries, and includes the steps of: collecting state of charge information of the battery in a standby mode state of the battery system; calculating a power change amount of the battery during a standby mode maintenance period based on the collected state of charge information and a state of pre-stored initial charge information; and comparing the calculated power change amount with an expected discharge power amount of the battery and determining whether or not leakage current is occurring in the battery system based on the comparison result.

[0024] The step of collecting the state of charge information of the battery may include the steps of collecting an open circuit voltage value (Vocv) measured after a predefined time has elapsed when the battery system is switched to a standby mode; determining a state of charge value (SOC) based on the open circuit voltage value (Vocv); and storing the determined state of charge value (SOC) as an initial state of charge value (SOC_init).

[0025] The step of collecting state of charge information of the battery may include determining a state of charge (SOC) value of the battery at predefined intervals in a standby mode of the battery system.

[0026] The step of calculating the amount of power change of the battery may include a step of calculating the amount of power change based on a difference value (Δ SOC) between a pre-stored initial state of charge value (SOC_init) and the calculated state of charge value (SOC).

[0027] The expected discharge power amount can be defined based on at least one of: a self-discharge power amount of the battery; and an internal supply power amount provided by the battery to a power demanding device located inside the battery system.

[0028] The expected discharge power amount can be defined as a value obtained by multiplying the sum of the self-discharge power amount and the power amount supplied by the battery to a battery management system (BMS) by a predefined weighting coefficient.

[0029] The step of determining whether leakage current occurs in the battery system may include a step of determining that leakage current occurs in the battery if the calculated power change amount exceeds the expected discharge power amount.

[0030] The method may further include collecting temperature values ​​of the battery in a standby mode state of the battery system; and calculating a temperature change amount of the battery based on the collected temperature values.

[0031] The step of determining whether leakage current has occurred in the battery system may include a step of determining that leakage current has occurred in the battery if the calculated power change amount exceeds the expected discharge power amount and the calculated temperature change amount exceeds a predefined reference temperature change amount.

[0032] The method may further include determining whether the battery is performing a balancing control operation, wherein determining whether leakage current is occurring in the battery system may include determining that leakage current is occurring in the battery when a first condition that the calculated power change amount exceeds the expected discharge power amount and a third condition that the battery is not performing a balancing control operation are satisfied.

[0033] The step of determining whether leakage current occurs in the battery system may include detecting one or more batteries in which leakage current occurs among a plurality of batteries included in the battery system.

[0034] In order to achieve the above and other objects, a battery system according to an embodiment of the present invention may include a plurality of batteries; and a battery management system (BMS) that monitors and controls the plurality of batteries.

[0035] The battery management device can collect charging information status of each of the batteries in a standby mode state of the battery system, calculate a power change amount of each of the batteries during a standby mode maintenance period based on the collected charging information status and a pre-stored initial charging information status, compare the power change amount for each of the batteries with an expected discharge power amount, and determine one or more batteries in which leakage current has occurred based on the comparison result. [Effects of the Invention]

[0036] According to the above-described embodiment of the present invention, it is possible to more accurately determine whether leakage current occurs in a battery system and which battery is generating leakage current without using a leakage current detection sensor. [Brief explanation of the drawings]

[0037] [Figure 1] 1 is a block diagram showing a battery system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a flow chart of a battery diagnostic method according to the present invention. [Figure 3] FIG. 2 is a flow chart of a battery diagnostic method according to an embodiment of the present invention. [Figure 4] FIG. 6 is a flow chart of a battery diagnostic method according to another embodiment of the present invention. [Figure 5] 1 is a block diagram illustrating an example of a battery system according to an embodiment of the present invention; [Figure 6] and [Figure 7] FIG. 6 is a block diagram for explaining the operation of the battery system shown in FIG. [Figure 8] 1 is a block diagram of a battery diagnostic device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0038] Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, it is understood that this is not intended to limit the present invention to the specific embodiments, but rather to include all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. Like reference numerals are used to refer to like elements throughout the drawings.

[0039] Terms such as "first," "second," "A," and "B" may be used to describe various components, but the components should not be limited by these terms. These terms are used only to distinguish one component from another. For example, a first component may be termed a "second component," and similarly, a second component may be termed a "first component," without departing from the scope of the present invention. The term "and / or" includes a combination of multiple associated listed items or any of multiple associated listed items.

[0040] When a component is referred to as being "coupled" or "connected" to another component, it is understood that the component may be directly coupled or connected to the other component, but that there may be other components in between. In contrast, when a component is referred to as being "directly coupled" or "directly connected" to another component, it is understood that there are no other components in between.

[0041] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly indicates otherwise. It should be understood that in this application, the terms "comprise" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and do not preclude the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0042] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as having an ideal or overly formal meaning unless expressly defined in this application.

[0043] Some terms used in this specification are defined as follows:

[0044] SOC (State of Charge) is the current charged state of the battery expressed as a percentage [%], and SOH (State of Health) is the current state of the battery compared to the ideal or original battery state expressed as a percentage [%].

[0045] A battery cell is the smallest unit that serves to store power, and a battery module refers to an assembly of a plurality of battery cells that are electrically connected together.

[0046] A battery pack or battery rack refers to the smallest single-structure system that can be monitored and controlled through a battery management device / system (BMS) by electrically connecting module units set by the battery manufacturer, and can be composed of multiple battery modules and one BPU or protection device.

[0047] A battery bank can refer to a large-scale battery rack system consisting of multiple battery racks connected in parallel. The battery bank BMS can monitor and control the battery rack BMS (RBMS).

[0048] A battery assembly refers to an assembly including a plurality of electrically connected battery cells that is applied to a specific system or device and functions as a power supply source. Here, the battery assembly may refer to a battery module, a battery pack, a battery rack, a battery bank, or the like, but the scope of the present invention is not limited to these.

[0049] FIG. 1 is a block diagram showing a battery system according to an embodiment of the present invention.

[0050] Referring to FIG. 1, the battery system may include a battery assembly 100 including a plurality of batteries 10 (BAT #1 to BAT #N), and a battery diagnostic device 200.

[0051] A plurality of batteries 10 can be electrically connected to form a battery assembly 100 .

[0052] The battery system according to the present invention may be embodied as being included in an energy storage system (ESS), but the scope of the present invention is not limited to this. That is, the battery system according to the present invention may be applied to various devices and may operate to detect an abnormal battery by performing the abnormal battery detection method described below.

[0053] Although the battery 10 according to the present invention refers to a battery cell, the scope of the present invention is not limited thereto. That is, the battery system according to the present invention may operate to detect an object in which an abnormality has occurred by performing the abnormal battery detection method described below on a battery cell, a battery module, a battery rack, or a battery pack.

[0054] The battery diagnostic device 200 may be implemented as being included in a battery management system (BMS) located inside the battery system.

[0055] The battery diagnostic device 200 calculates the amount of change in battery power based on status information collected when the battery system is in standby mode, and can determine whether leakage current is occurring in the battery system and the battery in which leakage current is occurring based on the calculated amount of change in battery power, the amount of change in battery temperature, and whether a balancing control operation is being performed when the battery system is in standby mode. In an embodiment, the battery diagnostic device 200 can determine whether leakage current is occurring in the battery system and the battery in which leakage current is occurring based on one or more of the amount of change in battery power, the amount of change in battery temperature, and whether a balancing control operation is being performed when the battery system is in standby mode.

[0056] That is, unlike the prior art that uses a leakage current detection sensor, the present invention can diagnose whether leakage current occurs by using a status information collecting device that is essential for a battery system.

[0057] Various embodiments of the present invention will be described in detail below with reference to FIGS.

[0058] FIG. 2 is a flow chart of the battery diagnostic method according to the present invention.

[0059] When the battery system is switched to the standby mode (S210), the battery diagnostic device 200 may collect state of charge information of the battery while the standby mode is maintained (S220). Here, the state of charge information may include an identifier and a state of charge (SOC) of the corresponding battery.

[0060] The battery diagnostic device 200 can collect open circuit voltages (Vocv) measured by a voltage measuring device and determine a state of charge (SOC) based on the collected open circuit voltages (Vocv). Here, the battery diagnostic device 200 can confirm the collected open circuit voltages (Vocv) and the corresponding SOC from a Vocv-SOC relationship graph for the corresponding battery, and determine the confirmed SOC as the SOC of the corresponding battery.

[0061] The battery diagnostic device 200 can determine the state of charge (SOC) of the battery at predefined time intervals. For example, the battery diagnostic device 200 can determine the state of charge (SOC) of the battery every second.

[0062] The battery diagnostic device 200 may calculate the amount of power change of the battery during the period in which the standby mode is maintained (S230). Here, the battery diagnostic device 200 may calculate the amount of power change based on the collected state of charging information and the state of pre-stored initial charging information.

[0063] More specifically, the battery diagnostic device 200 may determine an initial state of charge (SOC_init) based on an open-circuit voltage value measured for the first time after the battery system is switched to the standby mode, and store the initial state of charge (SOC_init) in a storage device (e.g., a non-volatile memory). Thereafter, the battery diagnostic device 200 may calculate a power change amount at a corresponding measurement point based on a difference between the initial state of charge (SOC_init) stored in the storage device and a state of charge (SOC_present) determined based on an open-circuit voltage value measured at a later point in time.

[0064] The battery diagnostic device 200 may compare the calculated power change amount with a predefined threshold value (S240), where the threshold value may be defined as an expected amount of discharge power of the corresponding battery.

[0065] The battery diagnostic device 200 can determine whether leakage current occurs in the battery system based on the result of comparing the amount of power change with a predefined threshold (S250). Here, if the amount of power change exceeds the predefined threshold, the battery diagnostic device 200 can determine that leakage current occurs in the corresponding battery.

[0066] That is, the battery diagnostic device 200 according to an embodiment of the present invention can determine that abnormal self-discharge, i.e., leakage current, has occurred in the corresponding battery if the amount of power change during the standby mode maintenance period exceeds a set threshold (e.g., expected discharge power amount).

[0067] FIG. 3 is a flow diagram of a battery diagnostic method according to an embodiment of the present invention.

[0068] When the battery system is switched to the standby mode (S310), the battery diagnostic device 200 may collect an initial open-circuit voltage value (Vocv_init) of the battery (S320). Here, the initial open-circuit voltage value (Vocv_init) may correspond to an open-circuit voltage value measured after a predefined time (e.g., 30 minutes) has elapsed since the battery system was switched to the standby mode.

[0069] The battery diagnostic device 200 can determine an initial state of charge value (SOC_init) based on the initial open circuit voltage value (Vocv_init) and store the determined initial state of charge value (SOC_init) in a storage device (e.g., non-volatile memory) (S330). Here, the battery diagnostic device 200 can confirm the state of charge value (SOC) corresponding to the initial open circuit voltage value (Vocv_init) from the Vocv-SOC relationship graph for the corresponding battery, and determine the confirmed state of charge value (SOC) as the initial state of charge value (SOC_init) for the corresponding battery.

[0070] Thereafter, the battery diagnostic device 200 collects the open circuit voltage value (Vocv) measured by the voltage measuring device, and determines the state of charge value (SOC_present) at the current time (the time when the open circuit voltage value is collected) based on the collected open circuit voltage value (Vocv) (S340).

[0071] The battery diagnostic device 200 calculates the difference (ΔSOC) between the initial state of charge value (SOC_init) stored in the memory device and the current state of charge value (SOC_present) (S350), and can calculate the power change (ΔP) at the corresponding time based on the calculated difference (ΔSOC) (S360).

[0072] Thereafter, the battery diagnostic device 200 may compare the calculated power change amount (ΔP) with a predefined threshold value (S370), where the threshold value may be defined as the expected discharge power amount of the corresponding battery.

[0073] In an embodiment, the expected discharge power amount may be defined based on at least one of a self-discharge power amount (P_sd) of the battery and an internal supply power amount (P_in) provided by the battery to a power-requesting device located inside the battery system. Here, the self-discharge power amount (P_sd) may refer to an expected self-discharge power amount calculated based on a pre-stored self-discharge rate of the battery. Also, the power-requesting device may refer to a device that operates by receiving power from the battery in a standby mode of the battery system.

[0074] In an embodiment, the expected discharge power can be defined as the sum (P_sd + P_in) of the battery's self-discharge power and the internal supply power. For example, the expected discharge power can be defined as the sum (P_sd + P_bms) of the battery's self-discharge power and the power supplied to the battery management system (BMS) by the battery in standby mode.

[0075] In another embodiment, the expected discharge power may be defined as a value (w * (P_sd + P_in)) obtained by multiplying a sum of the battery's self-discharge power and internal supply power by a predefined weighting factor (w). Here, the weighting factor (w) is a value defined to prevent erroneous diagnosis due to errors in the open-circuit voltage value and the state of charge value, and may be defined as a specific value, for example, greater than 1.0 and less than or equal to 1.3.

[0076] If the amount of power change (ΔP) is equal to or less than the threshold value (for example, the expected amount of discharged power) (NO in S370), the battery diagnostic device 200 can return to step S340 and perform the subsequent process again.

[0077] If the amount of power change (ΔP) exceeds the threshold value (expected amount of discharged power) (YES in S370), the battery diagnostic device 200 can determine that leakage current has occurred in the corresponding battery (S380).

[0078] In an embodiment, when a battery system includes a plurality of batteries, the battery diagnostic device 200 can detect a battery in which leakage current occurs among the plurality of batteries.

[0079] Specifically, the battery diagnostic device 200 calculates the power change (ΔP) for each battery (BAT #1 to BAT #N), detects a battery whose power change (ΔP) exceeds a threshold value (e.g., an expected discharge power amount), and determines that leakage current has occurred in the corresponding battery.

[0080] Here, if it is determined that leakage current has occurred in all batteries included in the battery system, the battery diagnosis device 200 may determine that leakage current has occurred in the entire battery system. For example, if it is determined that leakage current has occurred in all battery packs included in a battery rack, the battery diagnosis device 200 may determine that leakage current has occurred in the entire battery rack.

[0081] Fig. 4 is a flow chart of a battery diagnostic method according to another embodiment of the present invention, in which a battery diagnostic device determines whether leakage current occurs by taking into consideration at least one of a temperature change amount and whether a balancing control operation is performed in addition to a power change amount.

[0082] In an embodiment, the battery diagnostic device 200 can determine that leakage current has occurred in the corresponding battery if it satisfies a first condition that the amount of power change in standby mode exceeds the expected amount of discharge power, a second condition that the amount of power change in standby mode exceeds a predefined reference temperature change, and a third condition that the battery is in a state where balancing control operation is not being performed.

[0083] 4, when the battery system is switched to the standby mode (S410), the battery diagnostic device 200 may collect battery status information while maintaining the standby mode (S420). Here, the status information may include one or more of a battery identifier, a state of charge (SOC), and a temperature (T).

[0084] The battery diagnostic device 200 can collect battery status information at predefined time intervals. For example, the battery diagnostic device 200 can collect the state of charge (SOC) and temperature (T) of the battery every second.

[0085] The battery diagnostic device 200 calculates the power change (ΔP) and temperature change (ΔT) of the battery during the period in which the standby mode is maintained, and can determine whether the battery balancing control operation is being performed (S430).

[0086] More specifically, the battery diagnostic device 200 determines an initial state of charge (SOC_init) based on an open-circuit voltage value measured first after the battery system is switched to standby mode, and calculates a power change (ΔP) at the corresponding measurement point based on a difference between the initial state of charge (SOC_init) and a state of charge (SOC_present) at a subsequent point in time. The battery diagnostic device 200 also stores a temperature value (T_init) measured first after the battery system is switched to standby mode in a storage device, and calculates a temperature change (ΔT) at the corresponding measurement point based on a difference between the stored initial temperature value (T_init) and a temperature value (T_present) measured at a subsequent point in time. The battery diagnostic device 200 can also determine whether a battery balancing control operation is to be performed in conjunction with a balancing circuit that performs a balancing control operation to resolve a battery imbalance or a battery management device that controls the balancing circuit.

[0087] The battery diagnosis device 200 may determine whether one or more of the following conditions are satisfied (S440): a first condition that the calculated power change (ΔP) exceeds an expected discharge power amount; a second condition that the calculated temperature change (ΔT) exceeds a predefined reference temperature change; and a third condition that the battery is in a state where balancing control is not performed. Here, the reference temperature change of the second condition may be defined as the average value of the temperature changes of the remaining batteries excluding the battery being diagnosed, or may be defined as a value obtained by multiplying the average value by a predefined weighting coefficient.

[0088] The battery diagnostic device 200 can determine whether leakage current occurs in the battery system based on whether one or more of the first condition, the second condition, and the third condition are satisfied (S450).

[0089] In an embodiment, the battery diagnostic device 200 may determine that leakage current has occurred in a battery to be diagnosed if the battery satisfies the first and second conditions. That is, if the amount of power change in standby mode exceeds the expected amount of discharge power and the amount of temperature change exceeds a reference value, it may be determined that leakage current has occurred in the battery.

[0090] In another embodiment, the battery diagnostic device 200 may determine that leakage current has occurred in a battery to be diagnosed if the battery satisfies the first and third conditions. That is, if the power change amount in standby mode exceeds the expected discharge power amount and the battery is not performing a balancing control operation, it may be determined that leakage current has occurred in the battery. If the battery is performing a balancing control operation, the charging and discharging amount for balancing is reflected in the calculation of the power change amount, making it difficult to make an accurate diagnosis based solely on whether the first condition is satisfied. To prevent erroneous diagnosis due to the balancing operation, the battery diagnostic device 200 may determine whether leakage current has occurred by considering the third condition in addition to the first condition.

[0091] In yet another embodiment, the battery diagnostic device 200 can determine that leakage current has occurred in a battery to be diagnosed if the battery satisfies all of the first condition, the second condition, and the third condition.

[0092] FIG. 5 is a block diagram showing an example of a battery system according to an embodiment of the present invention, and FIGS. 6 and 7 are block diagrams for explaining the operation of the battery system shown in FIG.

[0093] Referring to FIG. 5, a battery system according to an embodiment of the present invention can be embodied in a battery pack 100'.

[0094] The battery pack 100' includes a plurality of battery modules (Module #1 to Module #N), and each of the battery modules may be configured to include a plurality of battery cells 10' (CELL #1 to CELL #N).

[0095] The battery diagnostic device according to the present invention may correspond to a battery management system (PBMS) 200' of a battery pack 100' or may be embodied as being included in the battery management system (PBMS) 200'.

[0096] When the battery pack is switched to the standby mode, the battery management system (PBMS) can collect an initial open circuit voltage value (Vocv_init) of each of the battery cells, determine an initial state of charge value (SOC_init) for each of the battery cells, and store it in a storage device (e.g., a non-volatile memory). The battery management system (PBMS) can also collect an initial temperature value (T_init) for each of the battery cells and store it in the storage device.

[0097] Thereafter, the battery management system (PBMS) can calculate the amount of power change (ΔP) for each battery cell per unit time based on the amount of change in the state of charge value (ΔSOC = SOC_init - SOC_present) while the battery pack is maintained in standby mode. Also, the battery management system (PBMS) can calculate the amount of change in temperature value (ΔT = T_init - T_present) per unit time while the battery pack is maintained in standby mode.

[0098] The battery management system (PBMS) can determine whether or not leakage current occurs by determining whether or not one or more of the first to third conditions are satisfied for each battery cell.

[0099] 6, if a battery cell whose power change (ΔP) exceeds the expected discharge power (satisfying the first condition) is detected among the plurality of battery cells, the battery management system (PBMS) may determine that leakage current has occurred in the corresponding battery (Cell #2 of Module #1). As another example, if a battery cell whose power change (ΔP) exceeds the expected discharge power (satisfying the first condition) and whose temperature change (ΔT) exceeds a reference temperature change (satisfying the second condition) is detected among the plurality of battery cells, the battery management system (PBMS) may determine that leakage current has occurred in the corresponding battery (Cell #2 of Module #1). As another example, if the battery management system (PBMS) detects a battery cell among multiple battery cells whose power change (△P) exceeds the expected discharge power amount (satisfying the first condition), whose temperature change (△T) exceeds the reference temperature change (satisfying the second condition), and whose cell balancing operation is not being performed (satisfying the third condition), it can determine that leakage current has occurred in the corresponding battery (Cell #2 of Module #1).

[0100] Referring to FIG. 7, if it is determined that leakage current has occurred in all battery cells included in the battery pack, the battery management system (PBMS) can determine that leakage current has occurred in the entire battery pack.

[0101] The battery management system (PBMS) may transmit leakage current diagnosis information to a higher-level battery management device. For example, the battery management system (PBMS) may transmit leakage current diagnosis results to at least one of a rack battery management system (RBMS), a battery section controller (BSC), an energy management system (EMS), and a power management system (PMS). Here, the leakage current diagnosis information may include one or more of whether leakage current is occurring, the number of batteries generating leakage current, and identifiers of batteries generating leakage current.

[0102] Meanwhile, the battery system according to the embodiment of the present invention may be embodied in a battery module, a battery rack, or a battery bank in addition to those shown in Figures 5 to 7, and in this case, the leakage current diagnosis method according to the present invention may be similarly performed.

[0103] FIG. 8 is a block diagram of a battery diagnostic device according to an embodiment of the present invention.

[0104] The battery diagnostic device 800 according to an embodiment of the present invention may include at least one processor 810, a memory 820 for storing at least one instruction to be executed by the processor, and a transceiver 830 connected to a network for communication.

[0105] The at least one instruction may include an instruction to collect charging information status of the battery in a standby mode state of the battery system; an instruction to calculate a power change amount of the battery during a standby mode maintenance period based on the collected charging information status and a pre-stored initial charging information status; and an instruction to compare the calculated power change amount with an expected discharge power amount of the battery and determine whether leakage current is occurring in the battery system based on the comparison result.

[0106] The command to collect the state of charge information of the battery may include a command to collect an open circuit voltage value (Vocv) measured after a predefined time has elapsed when the battery system is switched to a standby mode; a command to determine a state of charge value (SOC) based on the open circuit voltage value (Vocv); and a command to store the determined state of charge value (SOC) as an initial state of charge value (SOC_init).

[0107] The instructions for collecting state of charge information of the battery may include instructions for determining a state of charge (SOC) value of the battery at predefined intervals while the battery system is in standby mode.

[0108] The command to calculate the power change amount of the battery may include a command to calculate the power change amount based on a difference value (ΔSOC) between a pre-stored initial state of charge value (SOC_init) and the calculated state of charge value (SOC).

[0109] The expected discharge power amount can be defined based on at least one of: a self-discharge power amount of the battery; and an internal supply power amount provided by the battery to a power demanding device located inside the battery system.

[0110] The expected discharge power amount can be defined as a value obtained by multiplying the sum of the self-discharge power amount and the power amount supplied by the battery to a battery management system (BMS) by a predefined weighting coefficient.

[0111] The command to determine whether leakage current has occurred in the battery system may include a command to determine that leakage current has occurred in the battery if the calculated power change amount exceeds the expected discharge power amount.

[0112] The at least one instruction may further include an instruction to collect temperature values ​​of the battery when the battery system is in standby mode; and an instruction to calculate a temperature change amount of the battery based on the collected temperature values.

[0113] The command to determine whether leakage current has occurred in the battery system may include a command to determine that leakage current has occurred in the battery if the calculated power change amount exceeds the expected discharge power amount and the calculated temperature change amount exceeds a predefined reference temperature change amount.

[0114] The at least one command may further include a command to determine whether the battery is performing a balancing control operation, wherein the command to determine whether leakage current is occurring in the battery system may include a command to determine that leakage current is occurring in the battery when a first condition that the calculated power change amount exceeds the expected discharge power amount and a third condition that the battery is not performing a balancing control operation are satisfied.

[0115] The instruction to determine whether leakage current occurs in the battery system may include an instruction to detect one or more batteries in which leakage current occurs among a plurality of batteries included in the battery system.

[0116] The instruction to determine whether leakage current has occurred in the battery system may include an instruction to determine that leakage current has occurred in the entire battery system if it is determined that leakage current has occurred in all batteries included in the battery system.

[0117] The battery diagnostic device 800 may further include an input interface device 840, an output interface device 850, a storage device 860, etc. The components included in the battery diagnostic device 800 are connected to each other by a bus 770 to communicate with each other.

[0118] Here, the processor 810 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which the method according to the embodiment of the present invention is performed. The memory (or storage device) may be composed of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory may be composed of at least one of a read-only memory (ROM) and a random access memory (RAM).

[0119] The operations of the methods according to the embodiments of the present invention can be embodied as a computer-readable program or code on a computer-readable recording medium. The computer-readable recording medium includes all kinds of storage devices in which data that can be read by a computer system is stored. In addition, the computer-readable recording medium can be distributed among computer systems connected via a network, so that the computer-readable program or code can be stored and executed in a distributed manner.

[0120] Some aspects of the invention have been described in the context of an apparatus, but they may also be described in terms of a corresponding method, where a block or apparatus corresponds to a method step or feature of a method step. Similarly, aspects described in the context of a method may be described in terms of a corresponding block or item or feature of a corresponding apparatus. Some or all of the method steps may be performed by (or using) a hardware apparatus, such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most important method steps may be performed by such an apparatus.

[0121] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and variations of the present invention can be made without departing from the spirit and scope of the present invention as set forth in the following claims. [Explanation of symbols]

[0122] 10: Battery 100: Battery assembly 200, 700: Battery diagnostic equipment

Claims

1. A battery diagnostic device located in a battery system including one or more batteries, at least one processor; and a memory for storing a plurality of instructions to be executed by the at least one processor; The plurality of instructions: instructions for collecting state of charge information of the battery while the battery system is in a standby mode; instructions for calculating a power change amount of the battery during a standby mode maintenance period based on the collected state-of-charge information and pre-stored initial state-of-charge information; and a command to compare the calculated power change amount with an expected discharge power amount of the battery, and determine whether leakage current is occurring in the battery system based on the comparison result; The command to determine whether leakage current has occurred in the battery system includes a command to determine that leakage current has occurred in the battery if the calculated power change amount exceeds the expected discharge power amount, and The expected discharge power amount is defined as a value obtained by multiplying the sum of the self-discharge power amount of the battery and the power amount supplied by the battery to a battery management system (BMS) by a predefined weighting coefficient. Battery diagnostic device.

2. The instructions for collecting state of charge information of the battery include: instructions for collecting an open circuit voltage value (Vocv) measured after a predefined time period has elapsed when the battery system is switched into a standby mode; instructions for determining a state of charge value (SOC) based on the open circuit voltage value (Vocv); and storing the calculated state of charge value (SOC) as an initial state of charge value (SOC_init); The battery diagnostic device according to claim 1 .

3. The instructions for collecting state of charge information of the battery include: and instructions for determining a state of charge (SOC) value of the battery at predetermined intervals while the battery system is in a standby mode. The battery diagnostic device according to claim 1 .

4. The instruction to calculate the amount of change in power of the battery is and a command to calculate the power change amount based on a difference value (ΔSOC) between a pre-stored initial state of charge value (SOC_init) and the determined state of charge value (SOC). The battery diagnostic device according to claim 3 .

5. The plurality of instructions: instructions for collecting temperature values ​​of the battery while the battery system is in a standby mode; and and further comprising instructions for calculating a temperature change of the battery based on the collected temperature values. The battery diagnostic device according to claim 1 .

6. The instruction to determine whether leakage current occurs in the battery system includes: and an instruction to determine that leakage current has occurred in the battery when the calculated power change amount exceeds the expected discharge power amount and the calculated temperature change amount exceeds a predefined reference temperature change amount. The battery diagnostic device according to claim 5 .

7. The plurality of instructions: further comprising instructions for determining whether the battery is undergoing a balancing control operation; The instruction to determine whether leakage current occurs in the battery system includes: and a command to determine that leakage current has occurred in the battery when a first condition that the calculated power change amount exceeds the expected discharge power amount and a third condition that the battery is in a state where balancing control operation is not being performed are satisfied. The battery diagnostic device according to claim 1 .

8. The instruction to determine whether leakage current occurs in the battery system includes: and an instruction to detect one or more batteries that have generated leakage current among the plurality of batteries included in the battery system. The battery diagnostic device according to claim 1 .

9. A battery diagnostic method using a battery diagnostic device located in a battery system including one or more batteries, collecting state-of-charge information of the battery in a standby mode of the battery system; Calculating a power change amount of the battery during a standby mode maintenance period based on the collected charge state information and pre-stored initial charge state information; and comparing the calculated power change amount with an expected discharge power amount of the battery, and determining whether leakage current occurs in the battery system based on the comparison result; determining whether leakage current occurs in the battery system includes determining that leakage current occurs in the battery when the calculated power change amount exceeds the expected discharge power amount; The expected discharge power amount is It is defined as a value obtained by multiplying the sum of the self-discharge power amount of the battery and the power amount supplied by the battery to a battery management system (BMS) by a predefined weighting coefficient. Battery diagnostic methods.

10. The step of collecting state of charge information of the battery includes: collecting an open circuit voltage value (Vocv) measured after a predefined time has elapsed when the battery system is switched to a standby mode; Determining a state of charge value (SOC) based on the open circuit voltage value (Vocv); and storing the determined state of charge value (SOC) as an initial state of charge value (SOC_init); The battery diagnostic method according to claim 9 .

11. The step of collecting state of charge information of the battery includes: determining a state of charge (SOC) value of the battery at predetermined time intervals while the battery system is in a standby mode; The battery diagnostic method according to claim 9 .

12. The step of calculating the amount of change in power of the battery includes: Calculating the amount of change in power based on a difference (ΔSOC) between a pre-stored initial state of charge (SOC_init) and the calculated state of charge (SOC), The battery diagnostic method according to claim 11.

13. collecting temperature values ​​of the battery while the battery system is in standby mode; and and further comprising calculating a temperature change of the battery based on the collected temperature values. The battery diagnostic method according to claim 9 .

14. The step of determining whether leakage current occurs in the battery system includes: determining that leakage current has occurred in the battery when the calculated power change amount exceeds the expected discharge power amount and the calculated temperature change amount exceeds a predefined reference temperature change amount; The battery diagnostic method according to claim 13.

15. Further comprising the step of determining whether the battery is performing a balancing control operation; The step of determining whether leakage current occurs in the battery system includes: determining that leakage current has occurred in the battery when a first condition that the calculated power change amount exceeds the expected discharge power amount and a third condition that the battery is in a state where balancing control operation is not being performed are satisfied; The battery diagnostic method according to claim 9 .

16. The step of determining whether leakage current occurs in the battery system includes: detecting one or more batteries that have generated leakage current among the plurality of batteries included in the battery system; The battery diagnostic method according to claim 9 .

17. a plurality of batteries; and a battery management device that monitors and controls the plurality of batteries; The battery management device collecting state of charge information for each of said batteries while the battery system is in a standby mode; calculating a power change amount of each of the batteries during a standby mode maintenance period based on the collected charge state information and pre-stored initial charge state information; comparing the power change amount of each of the batteries with an expected discharge power amount; and determining that a leakage current has occurred in the battery if the calculated power change amount exceeds the expected discharge power amount; The expected discharge power amount is It is defined as a value obtained by multiplying the sum of the self-discharge power amount of the battery and the power amount supplied by the battery to a battery management system (BMS) by a predefined weighting coefficient. Battery system.

Images