Battery diagnosis device and operation method thereof

Abstract

A battery diagnosis device according to an embodiment disclosed in the present document may comprise: an interface for acquiring a voltage value measured for one or more battery cells during a designated time interval, and acquiring an external temperature of the battery cells; and a controller for calculating a difference between voltage values at two time points included in the designated time interval, selecting a discharge threshold value corresponding to the external temperature and a target time point among the two time points, and diagnosing a state of the battery cells by comparing the difference with the discharge threshold value.

Description

Battery diagnostic device and method of operation thereof

[0001] Cross-citation with related applications

[0002] This invention claims the benefit of priority from Korean Patent Application No. 10-2024-0122594, filed September 9, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] Embodiments disclosed in this document relate to a battery diagnostic device and an operating method thereof.

[0005] Recently, active research and development has been conducted on secondary batteries. The term "secondary battery" refers to a rechargeable battery, encompassing both conventional Ni / Cd and Ni / MH batteries, as well as more recent lithium-ion batteries. Among secondary batteries, lithium-ion batteries boast a significantly higher energy density than conventional Ni / Cd and Ni / MH batteries. Furthermore, lithium-ion batteries can be manufactured in a compact and lightweight form, making them a popular power source for mobile devices. Recently, their use has expanded to include power sources for electric vehicles, drawing attention as a next-generation energy storage medium.

[0006] As the industrial sector utilizing batteries expands, battery diagnostic devices (BMS: Battery Management Systems) that assess battery safety are also evolving. BMSs utilize various diagnostic algorithms to assess battery performance. Anomalies can include any cause that could lead to fire, such as damage or aging of the battery itself.

[0007] Additionally, the BMS can detect low-voltage cells by sensing the current and / or voltage values ​​of the battery and perform appropriate control, such as cell balancing, depending on the condition of the battery.

[0008] A low-voltage cell refers to a battery cell whose voltage drops significantly compared to other cells during the idle period. Low-voltage cells can cause voltage imbalances between cells. Consequently, failure to detect low-voltage cells can lead to unnecessary cell balancing to achieve voltage balance among battery cells, reducing the efficiency of battery packs containing low-voltage cells. Therefore, there is a need for a technology capable of early detection of low-voltage cells.

[0009] The technical problems of the embodiments disclosed in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the descriptions below.

[0010] A battery diagnosis device according to an embodiment disclosed in the present document may include an interface for obtaining a voltage value measured for one or more battery cells during a specified time period and obtaining an external temperature of the battery cell; and a controller for calculating a difference between voltage values ​​at two points in time included in the specified time period, selecting a discharge threshold corresponding to the external temperature and a target point in time among the two points in time, and comparing the discharge threshold with the difference to diagnose a state of the battery cell.

[0011] In one embodiment, in claim 1, the controller may select the discharge threshold from among the plurality of threshold voltage values ​​based on a lookup table (LUT) including a plurality of preset threshold voltage values ​​based on the external temperature and the target time point.

[0012] In one embodiment, the interface can further obtain the State Of Health (SOH) of the battery cell, and the controller can further select the discharge threshold by taking the SOH into consideration.

[0013] In one embodiment, the controller may select a lookup table corresponding to the SOH from among a plurality of SOC-specific lookup tables (LUTs) including a plurality of threshold voltage values ​​according to the external temperature and the target time, and may select the discharge threshold from among the plurality of threshold voltage values ​​included in the selected lookup table.

[0014] In one embodiment, the specified time may be included in the idle period of the battery.

[0015] In one embodiment, the two points in time may include a first point in time and a second point in time, the first point in time being the first point in time at which the voltage value is acquired, and the second point in time may correspond to a point in time at which m measurement cycles (m: a natural number) have passed from the first point in time.

[0016] In one embodiment, the target time point may correspond to the second time point.

[0017] In one embodiment, the controller may diagnose the battery cell as a low voltage battery cell if the difference is greater than or equal to the discharge threshold.

[0018] An operating method of a battery diagnosis device according to an embodiment disclosed in this document may include an operation of obtaining a voltage value measured during a specified time period for one or more battery cells; an operation of obtaining an external temperature of the battery cell; an operation of calculating a difference between voltage values ​​at two points in time included in the specified time period; an operation of selecting a discharge threshold corresponding to a target point in time among the external temperature and the two points in time; and an operation of comparing the discharge threshold with the difference to diagnose a state of the battery cell.

[0019] In one embodiment, the operation of selecting the discharge threshold may include an operation of selecting the discharge threshold from among the plurality of threshold values ​​based on a lookup table (LUT) including a plurality of threshold voltage values ​​set in advance based on the external temperature and the target time point.

[0020] In one embodiment, the operation may further include obtaining the State Of Health (SOH) of the battery cell, and the operation of selecting the discharge threshold may include selecting the discharge threshold by further considering the SOH.

[0021] In one embodiment, the operation of selecting the discharge threshold may include an operation of selecting a lookup table corresponding to the SOH among a plurality of SOC-specific lookup tables (LUTs) including a plurality of threshold voltage values ​​according to the external temperature and the target time, and an operation of selecting the discharge threshold among the plurality of threshold voltage values ​​included in the selected lookup table.

[0022] In one embodiment, the specified time may be included in the idle period of the battery.

[0023] In one embodiment, the two points in time may include a first point in time and a second point in time, the first point in time being the first point in time at which the voltage value is acquired, and the second point in time may correspond to a point in time at which m measurement cycles (m: a natural number) have passed from the first point in time.

[0024] In one embodiment, the target time point may correspond to the second time point.

[0025] In one embodiment, the diagnosing operation may include diagnosing the battery cell as a low voltage battery cell if the difference is greater than or equal to the discharge threshold.

[0026] The battery diagnosis device and its operating method according to various embodiments disclosed in this document can detect a low-voltage battery cell by diagnosing the state of the battery cell based on the timing of measuring the voltage of the battery cell and the external temperature of the battery cell, taking into account the characteristics of the battery cell in which the discharge amount changes depending on the temperature.

[0027] The effects of the battery diagnostic device and the operating method thereof according to the disclosure of this document are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art according to the disclosure of this document.

[0028] FIG. 1 is a block diagram of a battery diagnostic system according to one embodiment disclosed in this document.

[0029] FIG. 2 illustrates a block diagram of a battery pack including a battery diagnostic device according to one embodiment disclosed in the present document.

[0030] Figure 3 illustrates a temperature-dependent discharge graph according to one embodiment disclosed in this document.

[0031] FIG. 4 illustrates a lookup table including preset threshold voltage values ​​according to one embodiment disclosed in the present document.

[0032] FIGS. 5A and 5B illustrate a lookup table for each SOH containing preset threshold voltage values ​​according to one embodiment disclosed in the present document.

[0033] FIG. 6 is a flowchart illustrating an operation method of a battery diagnostic device according to an embodiment disclosed in this document.

[0034] FIG. 7 illustrates a computing system for executing operations of a battery diagnostic device according to an embodiment disclosed in this document.

[0035] In connection with the description of the drawings, the same or similar reference numerals may be used for identical or similar components.

[0036] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that the present invention encompasses various modifications, equivalents, and / or alternatives of the embodiments.

[0037] The embodiments and terminology used in this document are not intended to limit the technical features described in this document to a specific embodiment, but should be understood to encompass various modifications, equivalents, or alternatives of the embodiment. In connection with the description of the drawings, similar reference numerals may be used to refer to similar or related components. The singular form of a noun corresponding to an item may include one or more of the item, unless the relevant context clearly indicates otherwise.

[0038] In this document, the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" can each include any one of the items listed together in that phrase, or all possible combinations thereof. Terms such as "first", "second", "first", "second", "A", "B", "(a)", or "(b)" may be used merely to distinguish the corresponding component from other corresponding components, and do not limit the corresponding components in any other respect (e.g., importance or order) unless specifically stated otherwise.

[0039] In this document, when a component (e.g., a first component) is referred to as being “connected,” “coupled,” or “connected,” with or without the terms “functionally” or “communicatively,” or “coupled” or “connected,” it means that the component can be connected to the other component directly (e.g., wired or wirelessly), or indirectly (e.g., via a third component).

[0040] The methods according to various embodiments disclosed in this document may be provided as included in a computer program product. The computer program product may be traded as a commodity between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read-only memory, CD-ROM), or may be distributed online (e.g., downloaded or uploaded) through an application store or directly between two user devices. In the case of online distribution, at least a portion of the computer program product may be temporarily stored or temporarily generated in a machine-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

[0041] According to the embodiments disclosed in this document, each component (e.g., a module or a program) of the above-described components may include one or more entities, and some of the entities may be separated and placed in other components. According to the embodiments disclosed in this document, one or more components or operations of the aforementioned components may be omitted, or one or more other components or operations may be added. Alternatively or additionally, a plurality of components (e.g., a module or a program) may be integrated into a single component. In such a case, the integrated component may perform one or more functions of each of the plurality of components identically or similarly to those performed by the corresponding component among the plurality of components prior to the integration. According to the embodiments disclosed in this document, the operations performed by a module, program, or other component may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

[0042] FIG. 1 is a block diagram of a battery diagnostic system according to one embodiment disclosed in this document.

[0043] Referring to FIG. 1, a battery diagnostic system (1) may include a battery diagnostic device (10), a sensor (12), and one or more battery units (120, 140, 160).

[0044] The battery diagnostic device (10) can be connected to a sensor (12) by wire and / or wirelessly. The sensor (12) can include one or more sensors (e.g., a voltage measurement sensor, a temperature measurement sensor). The sensor (12) can measure values ​​related to the status of each of the battery units (120, 140, 160) and / or battery cells (121, 122, 123). The sensor (12) can measure values ​​related to the status of each of the battery units (120, 140, 160) and / or battery cells (121, 122, 123) at a constant cycle (e.g., every 100 seconds). Here, the values ​​related to the status may represent one or more values ​​for the voltage, current, resistance, state of charge (SOC), state of health (SOH), internal temperature and / or external temperature of the battery, or a combination thereof, of each of the battery units (120, 140, 160) and / or battery cells (121, 122, 123). Hereinafter, the values ​​related to the status may be referred to as 'status values'.

[0045] In one embodiment, the sensor (12) may be connected to one or more battery units (120, 140, 160) by wire and / or wirelessly to obtain status values ​​of the battery units (120, 140, 160). Each of the one or more battery units (120, 140, 160) may be a battery module, a battery pack, or a battery rack. In FIG. 1, only the first battery unit (120) to the third battery unit (160) are disclosed, but this is for convenience of explanation and the number of battery units is not limited thereto. In addition, in FIG. 1, battery cells (121, 122, 123) are illustrated as being included in the first battery unit (120), but this is for convenience of explanation and each of the second battery unit (140) and the third battery unit (160) may also include one or more battery cells. In addition, in FIG. 1, the number of battery cells (121, 122, 123) included in the first battery unit (120) is illustrated as three, but this is not limited thereto, and each of the battery cells (121, 122, 123) may be configured to include two or more battery cells.

[0046] In one embodiment, the sensor (12) and one or more battery units (120, 140, 160) may be included in an electronic device. Here, the electronic device may be a mobile device (e.g., a mobile phone, a laptop computer, a smart phone, a smart pad), an electric vehicle (e.g., an electric vehicle (EV), a hybrid EV (HEV), a plug-in HEV (PHEV), a fuel cell EV (FCEV)), an energy storage system (ESS), or a battery swapping system (BSS).

[0047] The battery diagnostic device (10) may be included in a server or PC external to the electronic device. The connection between the battery diagnostic device (10) and the electronic device may be a communication connection via a wired and / or wireless network. Here, the wired network may be based on LAN (local area network) communication or power line communication. The wireless network may be based on a short-range communication network (e.g., Bluetooth, WiFi (wireless fidelity), or IrDA (infrared data association)) or a long-range communication network (cellular network, 4G network, 5G network). In one embodiment, the connection between the battery diagnostic device (10) and the electronic device may be a connection via a device-to-device communication method (e.g., bus, GPIO (general purpose input and output), SPI (serial peripheral interface), or MIPI (mobile industry processor interface)).

[0048] In one embodiment, the battery diagnostic device (10) may be included in a BMS capable of diagnosing battery units (120, 140, 160) included in an electronic device, and operations performed in the battery diagnostic device (10) may be performed in the BMS.

[0049] In one embodiment, the battery diagnostic device (10) may be included in a server or charger that can diagnose battery units (120, 140, 160) external to the electronic device, and operations performed in the battery diagnostic device (10) may be performed in the external server or charger. In this case, the sensor (12) may not be included in the battery diagnostic device (10).

[0050] The battery diagnosis device (10) can obtain voltage values ​​for each of the battery units (120, 140, 160) and / or battery cells (121, 122, 123) measured through the sensor (12). The battery diagnosis device (10) can obtain external temperatures of the battery units (120, 140, 160) and / or battery cells (121, 122, 123) measured through the sensor (12). The battery diagnosis device (10) can calculate the difference between voltage values ​​at two points in time included in a specified time section. The battery diagnosis device (10) can select a discharge threshold corresponding to the external temperature and a target point in time among the two points in time. The battery diagnostic device (10) can diagnose the status of each of the battery units (120, 140, 160) and / or battery cells (121, 122, 123) by comparing the difference between the voltage values ​​and the discharge threshold.

[0051] Hereinafter, a method for each of the components included in the battery diagnosis device (10) to diagnose the state of the first battery cell (121) illustrated in FIG. 1 will be described. However, this is merely for convenience of explanation, and the battery diagnosis device (10) can diagnose the state of each of a plurality of battery cells (121, 122, 123) simultaneously or at different times.

[0052] The battery diagnostic device (10) may include an interface (100) and a controller (102). Here, the interface (100) and the controller (102) are referred to singularly, but depending on the embodiment, each of the interface (100) and the controller (102) may be configured in plural. Depending on the embodiment, the battery diagnostic device (10) illustrated in FIG. 1 may further include at least one component (e.g., a display, an input device, or an output device) other than the components illustrated in FIG. 1.

[0053] The interface (100) can obtain a voltage value measured during a specified time period for the first battery cell (121). Here, the specified time period may correspond to a specific time period among the charging period and the idle period included in the charging process for the first battery cell (121). For example, the charging process for the first battery cell (121) may repeat the charging period and the idle period multiple times, and the specified time period may be a time period included in at least one idle period during the charging process for the first battery cell (121).

[0054] In one embodiment, the interface (100) can obtain the voltage value of the first battery cell (121) measured by the sensor (12, see FIG. 1) in real time. In one embodiment, the interface (100) can also obtain the voltage value of the first battery cell (121) measured by the sensor (12, see FIG. 1) a certain amount of time after the measurement time.

[0055] The interface (100) can obtain the external temperature of the first battery cell (121). In one embodiment, the external temperature may be the temperature outside the case of the first battery cell (121) that protects components (e.g., electrodes and separators) included in the first battery cell (121). In one embodiment, when the first battery cell (121) is included in the first battery unit (120, see FIG. 1) as in FIG. 1, the external temperature may be the temperature outside the case of the first battery unit (120). In one embodiment, when the first battery cell (121) is included in the first battery module (220, see FIG. 2) as in FIG. 2, the external temperature may be the temperature outside the case of the first battery module (220) or the temperature outside the case of the battery pack (2, see FIG. 2).

[0056] In one embodiment, the interface (100) can acquire the external temperature measured by the sensor (12, see FIG. 1) in real time. In one embodiment, the interface (100) can also acquire the external temperature of the first battery cell (121) measured by the sensor (12, see FIG. 1) a certain amount of time after the measurement time.

[0057] According to various embodiments, the interface (100) may include various interface circuits for obtaining signals, information and / or data, such as sensors, communication circuits, etc.

[0058] The controller (102) can calculate the difference between voltage values ​​at two points in time within a specified time interval. Here, the two points in time may include a first point in time and a second point in time, and the second point in time may correspond to a point in time when m measurement cycles (m: a natural number) have passed from the first point in time. For example, if the measurement cycle is 100 seconds, the first point in time corresponds to 0 seconds, and the second point in time corresponds to a point in time when one measurement cycle has passed, the second point in time may correspond to 100 seconds.

[0059] In one embodiment, the controller (102) may calculate the difference by designating the first point in time as a fixed point in time (e.g., the initial point in time) and the second point in time (e.g., the point in time m measurement cycles from the first point in time) as a variable. In one embodiment, the controller (102) may also calculate the difference by designating both the first point in time (e.g., the kth (k: natural number) measured point in time) and the second point in time (e.g., the (k+1)th measured point in time) as variables.

[0060] The controller (102) may select an external temperature and a discharge threshold corresponding to a target time point among the two time points. Here, the target time point may correspond to one of the two time points, and the discharge threshold may be one of a plurality of threshold values ​​included in a lookup table (LUT) based on the external temperature and the target time point. For example, the lookup table may include threshold values ​​corresponding to the target time point for each external temperature. In one embodiment, the lookup table may be a lookup table based on the SOH (State of Health) and the target time point, and the discharge threshold may be one of a plurality of threshold values ​​included in the lookup table based on the SOH (State of Health) of the battery cell and the target time point. For example, the lookup table may include threshold values ​​corresponding to the target time point for each SOH of the battery cell. In one embodiment, the lookup table may include threshold voltage values ​​that further consider the SOH (State of Health) of the battery cell, and may include a plurality of lookup tables for each SOH. Depending on the embodiment, the lookup table may be stored in a memory (not shown) included in the battery diagnostic device (10), or may be received by the battery diagnostic device (10) from an external server. Specific details regarding the discharge threshold are described later in FIGS. 4, 5A, and 5B.

[0061] The controller (102) can compare the difference with a discharge threshold. The controller (102) can diagnose the status of the first battery cell (121) based on the result of comparing the difference with the discharge threshold. In one embodiment, the controller (102) can diagnose the first battery cell (121) as a low-voltage cell if the difference is greater than or equal to the discharge threshold.

[0062] In one embodiment, the controller (102) may reflect a compensation value to the difference based on the result of cell balancing performed between two points in time at which voltage values ​​are measured. The controller (102) may compare the difference with the compensation value reflected and the discharge threshold value to diagnose the condition of the first battery cell (121).

[0063] The battery diagnosis device (10) can diagnose in real time whether the first battery cell (121) is low voltage by comparing the above difference with the discharge threshold. In addition, the battery diagnosis device (10) can also diagnose later whether the first battery cell (121) is a low voltage cell through the charging record of the previously charged first battery cell (121). Based on the above, the battery diagnosis device (10) can prevent performance degradation due to low voltage cells and fire due to overcharging at an early stage by detecting whether the first battery cell (121) is a low voltage cell at an early stage.

[0064] FIG. 2 illustrates a block diagram of a battery pack including a battery diagnostic device according to one embodiment disclosed in the present document.

[0065] Referring to FIG. 2, a battery pack (2) may include a BMS (20) and battery modules (220, 240, 260). The BMS (20) may include a battery diagnostic device (10) and, depending on the embodiment, may further include a sensor (12). In FIG. 2, three battery modules are illustrated, but this is merely for convenience of explanation, and the battery pack (2) may include one or more battery modules. In addition, in FIG. 2, only battery cells (221, 222, 223) included in the first battery module (220) are illustrated, but this is merely for convenience of explanation, and the second battery module (240) and the third battery module (260) may also include a plurality of battery cells. In addition, although FIG. 2 illustrates that the first battery module (220) includes three battery cells (221, 222, 223), this is not limited to the number of battery cells, and each of the battery cells (121, 122, 123) may include two or more battery cells. In addition, the battery cells (221, 222, 223) illustrated in FIG. 2 may be identical to the battery cells (121, 122, 123) illustrated in FIG. 1.

[0066] According to various embodiments, when the battery pack (2) has a cell-to-pack (CTP) structure, the battery pack (2) may be configured to include a plurality of battery cells (121, 122, 123) without distinction of battery modules.

[0067] Fig. 3 illustrates a temperature-dependent discharge graph according to an embodiment disclosed in the present document. Fig. 4 illustrates a lookup table including preset threshold voltage values ​​according to an embodiment disclosed in the present document. Figs. 5a and 5b illustrate a lookup table for each SOH including preset threshold voltage values ​​according to an embodiment disclosed in the present document. Hereinafter, the lookup tables mentioned in Figs. 1 and 2 will be described with reference to Figs. 3 to 5b.

[0068] Referring to Fig. 3, a discharge graph (30) can be obtained through a discharge experiment on a normal battery cell conducted in advance. The x-axis of the discharge graph (30) may represent the capacity (unit: mAh or Ah) of the normal battery cell, and the y-axis may represent the voltage of the normal battery cell. Here, a normal battery cell may refer to a battery cell diagnosed as normal, rather than a low-voltage cell.

[0069] Referring to the discharge graph (30), each of the discharge curves has the same C-rate (e.g., 1C) and different external temperatures of 45 degrees Celsius, 25 degrees Celsius, and -10 degrees Celsius, respectively. Referring to the discharge graph (30), it can be confirmed that the lower the external temperature of a normal battery cell, the more severe the deviation from the SOC-OCV curve becomes.

[0070] Based on the characteristics of the discharge graph (30), the lookup table mentioned in FIGS. 1 and 2 can be constructed. The aforementioned lookup table can include threshold voltage values ​​according to external temperature based on the self-discharge amount of a normal battery confirmed by external temperature through the discharge graph for a normal battery cell.

[0071] FIG. 4 is an example of the lookup table described above, which sets a plurality of threshold values ​​(V) based on an external temperature (400) and a target time point (402). 1,1 , V 1,2 , ..., V n,1) is exemplified. Here, the target time point (402) may be a time point corresponding to the second time point among the first time point and the second time point included in a designated time interval (e.g., an idle period). For example, if the first time point is 0 seconds and the second time point is 100 seconds, the target time point (P2) may be 100 seconds corresponding to the second time point. The plurality of preset threshold values ​​may be values ​​calculated through a previously performed experiment based on the discharge characteristics of a normal battery cell according to the external temperature based on the discharge graph (30) of FIG. 3.

[0072] The first lookup table (40) may include a threshold voltage value set in advance according to the external temperature (400) and the target time point (402). Referring to the first lookup table (40), when the external temperature (400) is T1, the voltage value at the first time point is V1, and the voltage value at the second time point is V2, the battery diagnostic device (10) calculates the difference (V1-V2) and calculates the discharge threshold value V corresponding to the difference. 1,2 can be selected.

[0073] In Fig. 4, a plurality of threshold values ​​(V) are set based on the external temperature (400) and the target time point (402). 1,1 , V 1,2 , ..., V n,1) is exemplified, but the embodiment of the present invention is not limited thereto. In one embodiment, the battery diagnosis device (10) may select a discharge threshold using a lookup table including a plurality of threshold values ​​preset based on the SOH and the target time point (402). In another embodiment, as described below with reference to FIGS. 5A and 5B, the battery diagnosis device (10) may select a discharge threshold using a lookup table including a plurality of threshold values ​​preset based on the SOH and the external temperature. In summary, the battery diagnosis device (10) may select a discharge threshold using a lookup table including threshold values ​​preset based on the SOH and / or the external temperature.

[0074] FIGS. 5A and 5B each illustrate a second lookup table including a plurality of SOC-specific lookup tables (50, 52) that further consider SOH in addition to external temperature and target time, as an example of the aforementioned lookup table. Referring to FIGS. 5A and 5B, the second lookup table may include a first sub-lookup table (50) having an SOH of A% (500) and a second sub-lookup table (52) having an SOH of B% (520).

[0075] The battery diagnostic device (10) can select the first sub lookup table (50) from the second lookup table when the SOH of the first battery cell (121) is A% (500). The battery diagnostic device (10) can select the threshold voltage values ​​(V) included in the first sub lookup table (50). 1,1,A , V 1,2,A , ..., V n,1,A) can select a discharge threshold corresponding to the external temperature and target time of the first battery cell (121). Similarly, the battery diagnosis device (10) can select the second sub lookup table (52) among the second lookup tables when the SOH of the first battery cell (121) is B% (520). The battery diagnosis device (10) can select the threshold voltage values ​​(V) included in the second sub lookup table (52). 1,1,B , V 1,2,B , ..., V n,1,B ) can select a discharge threshold corresponding to the external temperature and target time of the first battery cell (121).

[0076] FIG. 6 is a flowchart illustrating an operation method of a battery diagnostic device according to an embodiment disclosed in this document.

[0077] Referring to FIG. 6, in operation 600, the battery diagnostic device (10) can obtain the voltage value and external temperature of the first battery cell (121).

[0078] The battery diagnostic device (10) can obtain a voltage value measured for a specified time period for the first battery cell (121). The battery diagnostic device (10) can obtain the voltage value of the first battery cell (121) measured by the sensor (12, see FIG. 1) in real time.

[0079] In one embodiment, the battery diagnostic device (10) may obtain the voltage value of the first battery cell (121) measured by the sensor (12, see FIG. 1) after a certain time from the measurement time.

[0080] The battery diagnostic device (10) can obtain the external temperature of the first battery cell (121). In one embodiment, the external temperature may be the temperature outside the case of the first battery cell (121) that protects components (e.g., electrodes and separators) included in the first battery cell (121). In one embodiment, when the first battery cell (121) is included in the first battery unit (120, see FIG. 1) as in FIG. 1, the external temperature may be the temperature outside the case of the first battery unit (120). In one embodiment, when the first battery cell (121) is included in the first battery module (220, see FIG. 2) as in FIG. 2, the external temperature may be the temperature outside the case of the first battery module (220) or the temperature outside the case of the battery pack (2, see FIG. 2).

[0081] In one embodiment, the battery diagnostic device (10) can obtain the external temperature measured by the sensor (12, see FIG. 1) in real time. In one embodiment, the battery diagnostic device (10) can also obtain the external temperature of the first battery cell (121) measured by the sensor (12, see FIG. 1) a certain amount of time after the measurement time.

[0082] In operation 620, the battery diagnostic device (10) can calculate the difference between voltage values ​​at two points in time. The battery diagnostic device (10) can calculate the difference between voltage values ​​at two points in time included in a specified time interval.

[0083] In one embodiment, the battery diagnostic device (10) can calculate the difference by designating the first point in time as a fixed point in time (e.g., the initial point in time) and designating the second point in time (e.g., the point in time m measurement cycles from the first point in time) as a variable.

[0084] In one embodiment, the battery diagnostic device (10) may calculate the difference by designating both the first time point (e.g., the kth (k: natural number) measured time point) and the second time point (e.g., the (k+1)th measured time point) as variables.

[0085] In operation 640, the battery diagnostic device (10) may select a discharge threshold. The battery diagnostic device (10) may select a discharge threshold corresponding to an external temperature and a target time point among the two time points. The battery diagnostic device (10) may select the discharge threshold based on a lookup table. In one embodiment, the lookup table may include at least one of the lookup tables (40, 50, 52) disclosed in FIGS. 4, 5A, and 5B.

[0086] In operation 660, the battery diagnosis device (10) can diagnose the state of the first battery cell by comparing the difference with the discharge threshold. The battery diagnosis device (10) can diagnose the state of the first battery cell (121) based on the result of comparing the difference with the discharge threshold. In one embodiment, the battery diagnosis device (10) can diagnose the first battery cell (121) as a low-voltage cell if the difference is greater than or equal to the discharge threshold.

[0087] FIG. 7 illustrates a computing system for executing operations of a battery diagnostic device according to an embodiment disclosed in this document.

[0088] Referring to FIG. 7, a computing system (70) according to one embodiment disclosed in this document may include an MCU (700), a memory (710), an input / output I / F (720), and a communication I / F (730).

[0089] The MCU (700) may be a processor that executes various programs (e.g., a battery diagnosis program) stored in the memory (710), processes various data from these programs, and performs the functions of the battery diagnosis device (10) shown in the aforementioned FIGS. 1 to 6.

[0090] The memory (710) can store various programs related to the operation of the battery diagnostic device (10). In addition, the memory (710) can store operation data of the battery diagnostic device (10).

[0091] A plurality of such memories (710) may be provided as needed. The memories (710) may be volatile memories or non-volatile memories. As volatile memories (710), RAM, DRAM, SRAM, etc. may be used. As non-volatile memories (710), ROM, PROM, EAROM, EPROM, EEPROM, flash memories, etc. may be used. The examples of the memories (710) listed above are merely examples and are not limited to these examples.

[0092] The input / output I / F (720) can provide an interface that enables data transmission and reception between an input device (not shown) such as a keyboard, mouse, or touch panel, and an output device (not shown) such as a display and the MCU (700).

[0093] The communication I / F (730) is a component capable of transmitting and receiving various data with the server, and may be any device capable of supporting wired or wireless communication. For example, diagnostic algorithms and lookup tables can be transmitted and received from a separately provided external server via the communication I / F (730).

[0094] The terms "include," "comprise," or "have" used herein, unless otherwise specifically stated, imply that the corresponding component may be included, and therefore should be interpreted to include other components rather than to exclude other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiments disclosed in this document pertain, unless otherwise defined. Commonly used terms, such as terms defined in dictionaries, should be interpreted to be consistent with their contextual meaning in the relevant art, and shall not be interpreted in an idealized or overly formal sense, unless explicitly defined in this document.

[0095] The above description is merely an example of the technical idea disclosed in this document, and those skilled in the art to which the embodiments disclosed in this document pertain may make various modifications and variations without departing from the essential characteristics of the embodiments disclosed in this document. Therefore, the embodiments disclosed in this document are not intended to limit the technical idea of ​​the embodiments disclosed in this document, but to explain it, and the scope of the technical idea disclosed in this document is not limited by these embodiments. The scope of protection of the technical idea disclosed in this document should be interpreted by the claims below, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of rights of this document.

Claims

1. Obtain voltage values ​​measured for a specified time interval for one or more battery cells, an interface for obtaining the external temperature of the battery cell; and Calculate the difference between the voltage values ​​at two points in time within the above-mentioned time interval, Select the discharge threshold corresponding to the target time point among the above external temperature and the above two time points, Including a controller that diagnoses the state of the battery cell by comparing the discharge threshold and the difference. Battery diagnostic device.

2. In claim 1, The above controller, Selecting the discharge threshold from among the plurality of threshold voltage values ​​based on a lookup table (LUT) including a plurality of preset threshold voltage values ​​based on the external temperature and the target time point, Battery diagnostic device.

3. In claim 1, The above interface is, Obtain the SOH (State Of Health) of the above battery cell, The above controller, The discharge threshold is selected by further considering the above SOH. Battery diagnostic device.

4. In claim 3, The above controller, Selecting a lookup table corresponding to the SOH from among a plurality of SOC-specific lookup tables (LUTs) including a plurality of threshold voltage values ​​according to the external temperature and the target time, Selecting the discharge threshold from among the plurality of threshold voltage values ​​included in the above-mentioned selected lookup table, Battery diagnostic device.

5. In claim 1, The above specified time is included in the rest period of the battery. Battery diagnostic device.

6. In claim 1, The above two points in time include the first point in time and the second point in time, The above first point in time is the first point in time at which the voltage value is obtained, The above second point in time corresponds to a point in time when m measurement cycles (m: natural number) have passed from the above first point in time. Battery diagnostic device.

7. In claim 6, The above target time point corresponds to the second time point, Battery diagnostic device.

8. In claim 1, The above controller, If the above difference is greater than the discharge threshold, the battery cell is diagnosed as a low-voltage battery cell. Battery diagnostic device.

9. An operation of obtaining a voltage value measured for a specified time period for one or more battery cells; An operation of obtaining the external temperature of the above battery cell; An operation of calculating the difference between voltage values ​​at two points in time included in the above-mentioned specified time; An operation of selecting a discharge threshold corresponding to the target time point among the above external temperature and the above two time points; and Comprising an operation of diagnosing the state of the battery cell by comparing the discharge threshold and the difference. Method of operation of a battery diagnostic device.

10. In claim 9, The operation of selecting the above discharge threshold is: An operation of selecting the discharge threshold from among the plurality of threshold values ​​based on a lookup table (LUT) including a plurality of threshold voltage values ​​set based on the external temperature and the target time point, Method of operation of a battery diagnostic device.

11. In claim 9, Further comprising an operation of obtaining the SOH (State Of Health) of the battery cell, The operation of selecting the above discharge threshold is: Including an operation of selecting the discharge threshold by further considering the SOH. Method of operation of a battery diagnostic device.

12. In claim 11, The operation of selecting the above discharge threshold is: An operation of selecting a lookup table corresponding to the SOH among a plurality of SOC-specific lookup tables (LUTs) including a plurality of threshold voltage values ​​according to the external temperature and the target time, and An operation of selecting the discharge threshold from among the plurality of threshold voltage values ​​included in the selected lookup table, Method of operation of a battery diagnostic device.

13. In claim 9, The above specified time is included in the rest period of the battery. Method of operation of a battery diagnostic device.

14. In claim 9, The above two points in time include the first point in time and the second point in time, The above first point in time is the first point in time at which the voltage value is obtained, The above second point in time corresponds to a point in time when m measurement cycles (m: natural number) have passed from the above first point in time. Method of operation of a battery diagnostic device.

15. In claim 14, The above target time point corresponds to the second time point, Method of operation of a battery diagnostic device.

16. In claim 9, The above diagnostic action is, Including an operation of diagnosing the battery cell as a low voltage battery cell when the difference is greater than or equal to the discharge threshold. Method of operation of a battery diagnostic device.

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