Battery diagnostic device and its operating method

Abstract

The battery diagnostic device includes an information acquisition unit that measures the voltage and current of the battery, and a controller that calculates the battery's charging capacity and discharging capacity based on the voltage and current, and diagnoses the battery based on the charging capacity, discharging capacity, and the difference between the charging OCV (Open Circuit Voltage) and the discharging OCV.

Description

Technical Field

[0001] The present invention claims the benefit of priority based on Korean Patent Application No. 10-2023-0068552 filed on May 26, 2023, and all the contents disclosed in the document of the Korean patent application are incorporated herein by reference in their entirety. The embodiments disclosed in this document relate to a battery diagnostic device and an operating method thereof.

Background Art

[0002] Currently commercialized batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium-ion batteries, etc. Among them, lithium-ion batteries have attracted attention because they have almost no memory effect compared to nickel-based batteries, allowing free charging and discharging, having a very low self-discharge rate, and a high energy density.

[0003] A lithium-ion battery includes a positive electrode, a negative electrode, an electrolyte, and a separator, and is a secondary battery capable of charging and discharging by the movement of lithium ions through the electrolyte between the positive electrode and the negative electrode.

[0004] When a battery catches fire during use of such a battery, a major accident may occur due to the reaction of chemicals inside the battery. To prevent this, a technique has been developed to diagnose the state of the battery by observing whether the voltage of the battery exceeds a preset voltage or whether the temperature of the battery exceeds a preset temperature. However, when predicting the ignition of a battery based on the voltage and temperature of the battery, there is a limit in that it is difficult to ensure the accuracy and reliability of the prediction.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the embodiments disclosed in this document is to provide a battery diagnostic device and an operating method thereof that can pre-diagnose the risk of short circuit, lithium precipitation, and battery ignition inside the battery.

[0006] The technical problems of the embodiments described herein are not limited to those mentioned above, and other technical problems not mentioned can be clearly understood by a person ordinary to the art in which the present invention pertains from the following description. [Means for solving the problem]

[0007] A battery diagnostic device according to one embodiment disclosed herein includes an information acquisition unit that measures the voltage and current of a battery, and a controller that calculates the charging capacity and discharging capacity of the battery based on the voltage and current, and diagnoses the battery based on the charging capacity, discharging capacity, and the difference between the charging OCV (Open Circuit Voltage) and the discharging OCV.

[0008] According to one embodiment, the controller calculates the difference between the charging capacity and the discharging capacity, and if the difference between the charging capacity and the discharging capacity exceeds a first reference value, the controller can determine that the battery is abnormal.

[0009] According to one embodiment, the controller can determine that the battery is in a dangerous state if the difference between the charging OCV and the discharging OCV is less than a second reference value.

[0010] According to one embodiment, the controller calculates the first difference, second difference, and third difference, which are the difference values ​​between the charging OCV and the discharging OCV, corresponding to the first, second, and third consecutive charge-discharge cycles of the battery, and determines that the state of the battery is in a dangerous state if the second difference is smaller than the first difference and the third difference is smaller than the second difference.

[0011] According to one embodiment, the controller can calculate the rate of change of the discharge OCV, and if the rate of change of the discharge OCV falls outside a previously set range, it can determine that the state of the battery is in a dangerous state.

[0012] According to one embodiment, the controller can calculate the rate of change of the charging OCV, and if the rate of change of the charging OCV falls outside a previously set range, it can determine that the state of the battery is in a dangerous state.

[0013] According to one embodiment, the controller can determine that a short circuit or lithium deposition has occurred inside the battery if the rate of change of the charging OCV and the rate of change of the discharging OCV are within a set range.

[0014] According to one embodiment, the controller can determine that the state of the battery is normal when the difference between the charging capacity and the discharging capacity is less than or equal to a first reference value.

[0015] A battery diagnostic method according to one embodiment disclosed herein includes the operation of acquiring the battery's charge capacity, discharge capacity, charge OCV (Open Circuit Voltage), and discharge OCV; the operation of calculating the difference between the charge capacity and the discharge capacity and the difference between the charge OCV and the discharge OCV; and the operation of determining the state of the battery based on the difference between the charge capacity and the discharge capacity and the difference between the charge OCV and the discharge OCV.

[0016] According to one embodiment, the operation for determining the state of the battery may be an operation in which the state of the battery is determined to be normal when the difference between the charging capacity and the discharging capacity is less than or equal to a first reference value.

[0017] According to one embodiment, the operation for determining the state of the battery may include an operation for determining whether the difference between the charging OCV and the discharging OCV is less than a second reference value if the difference between the charging capacity and the discharging capacity exceeds a first reference value.

[0018] According to one embodiment, the operation for determining the state of the battery may include an operation for determining the state of the battery to be in a dangerous state if the difference between the charge OCV and the discharge OCV is less than a second reference value.

[0019] According to one embodiment, the operation of determining the state of the battery includes calculating first differences, second differences, and third differences, which are the difference values between the charging OCV and the discharging OCV corresponding to the first cycle, the second cycle, and the third cycle, respectively, among a plurality of charge-discharge cycles of the battery in sequence, and determining that the state of the battery is a dangerous state when the second difference is smaller than the first difference and the third difference is smaller than the second difference.

[0020] According to one embodiment, the operation of determining the state of the battery may include determining that a short circuit or lithium precipitation has occurred inside the battery when the difference between the charging OCV and the discharging OCV is equal to or greater than a second reference value. Specific matters of other embodiments are included in the detailed description and the drawings.

Effects of the Invention

[0021] According to the battery diagnosis device and its operation method according to the embodiments disclosed in this document, the state of the battery can be diagnosed based on the charge capacity, discharge capacity, charging OCV, and discharging OCV obtained based on the current and voltage during charging and discharging of the battery.

[0022] According to the battery diagnosis device and its operation method according to the embodiments disclosed in this document, a short circuit or lithium precipitation inside the battery can be detected. According to the battery diagnosis device and its operation method according to the embodiments disclosed in this document, the ignition dangerous state of the battery can be diagnosed in advance.

Brief Description of the Drawings

[0023] [Figure 1] It is a block diagram showing a battery pack according to an embodiment disclosed in this document. [Figure 2] It is a block diagram showing a battery diagnosis device according to an embodiment disclosed in this document. [Figure 3] It is a graph showing a situation where a battery diagnosis device according to an embodiment disclosed in this document diagnoses a short circuit or lithium precipitation inside the battery. [Figure 4] A graph showing a situation where a battery diagnostic device according to an embodiment disclosed in this document diagnoses a fire risk state of a battery. [Figure 5] A graph showing that a battery diagnostic device according to an embodiment disclosed in this document considers changes in charging OCV and discharging OCV to diagnose a fire risk state of a battery. [Figure 6] A flowchart showing a battery diagnostic method according to an embodiment disclosed in this document. [Figure 7] A flowchart specifically showing an operation of determining the state of the battery in FIG. 6. [Figure 8] A diagram showing a computing system that executes a battery diagnostic method according to an embodiment disclosed in this document.

Mode for Carrying Out the Invention

[0024] Hereinafter, the embodiments disclosed in this document will be described in detail with reference to exemplary drawings. It should be noted that when attaching reference numerals to the components of each drawing, the same components are given the same numerals as much as possible when they are shown on other drawings. Also, when explaining the embodiments disclosed in this document, if a specific explanation of a related known configuration or function is determined to impede the understanding of the embodiments disclosed in this document, the detailed explanation thereof will be omitted.

[0025] In describing the components of the embodiments disclosed herein, terms such as "first," "second," etc., may be used. Such terms are merely for distinguishing a component from other components, and do not limit the nature, order, or sequence of the component. Furthermore, unless otherwise specifically defined, all terms used herein, including technical or scientific terms, have the same meaning as those generally understood by a person of ordinary skill in the art to which the embodiments disclosed herein belong. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as an ideal or overly formal meaning unless explicitly defined in this application.

[0026] Figure 1 is a block diagram showing a battery pack according to one embodiment disclosed in this document. Referring to Figure 1, a battery control system including a battery pack 1 according to one embodiment disclosed in this document and a higher-level controller 2 included in a higher-level system is schematically shown.

[0027] As shown in Figure 1, the battery pack 1 may include one or more battery cells 11, a switching unit 14 connected in series to the first terminal and / or second terminal of the battery cell 11 for controlling the flow of charge and discharge current to the battery cell 11, and a battery management system 20 that monitors the voltage, current, temperature, etc. of the battery pack 1 and manages to prevent overcharging and over-discharging.

[0028] In this case, the battery pack 1 can be equipped with multiple battery cells 11, sensors 12, switching units 14, and battery management systems 20. For example, the first terminal may be the (+) terminal of the battery cell 11, and the second terminal may be the (-) terminal.

[0029] Here, the switching unit 14 is an element for controlling the flow of current for charging or discharging multiple battery cells 11, and for example, at least one relay, electromagnetic contactor, etc. can be used depending on the specifications of the battery pack 1.

[0030] The battery management system 20 is an interface that receives input values ​​of the various parameters mentioned above, and may include multiple terminals and circuits connected to these terminals that process the input values. The battery management system 20 can also control the ON / OFF state of the switching unit 14, such as a relay or contactor, and can be connected to the battery cell 11 to monitor the state of each battery cell 11.

[0031] The higher-level controller 2 can transmit control signals to the battery management system 20 for the battery cells 11. This allows the battery management system 20 to be controlled based on the signals applied from the higher-level controller 2.

[0032] According to one embodiment, the battery management system 20 may include the battery diagnostic device 100 shown in Figure 2. According to another embodiment, the battery management system 20 may be a different system from the battery diagnostic device 100 shown in Figure 2. That is, the battery diagnostic device 100 shown in Figure 2 may be included in the battery pack 1, or it may be configured as another device outside the battery pack 1. For the sake of convenience, the following explanation will assume that the battery diagnostic device 100 is configured as another device outside the battery pack 1, but it is not limited to this. For example, the operation of the battery diagnostic device 100 described below may be performed by a BMS (Battery management system) in the vehicle, as well as by various devices such as a server, cloud, charger, or charger / discharger.

[0033] Figure 2 is a block diagram showing a battery diagnostic device according to one embodiment disclosed in this document. Referring to Figure 2, the battery diagnostic device 100 may include a charge / discharge unit 110, an information acquisition unit 120, and a controller 130. The battery diagnostic device 100 can diagnose the state of the battery 200 using the charge / discharge unit 110, the information acquisition unit 120, and the controller 130. According to this embodiment, the battery diagnostic device 100 can be connected to the battery 200.

[0034] The charging / discharging unit 110 can charge and discharge the battery 200. The charging / discharging unit 110 can charge or discharge the battery 200 by supplying voltage or current to the battery 200.

[0035] The charge / discharge unit 110 can charge and discharge the battery 200 over multiple cycles. This allows the battery diagnostic device 100 to perform cycle tests on the battery 200 using the charge / discharge unit 110.

[0036] The information acquisition unit 120 can acquire information about the battery 200. According to the embodiment, the information acquisition unit 120 can acquire voltage information and current information of the battery 200. For example, the information acquisition unit 120 can acquire voltage and current corresponding to each of multiple charge-discharge cycles of the battery 200. In particular, the information acquisition unit 120 can measure the voltage at the end of charging and the voltage at the end of discharging included in each charge-discharge cycle. Here, the voltage at the end of charging of the battery 200 can be defined as the charge OCV (Open Circuit Voltage). Also, the voltage at the end of discharging of the battery 200 can be defined as the discharge OCV.

[0037] The controller 130 can calculate the charge capacity of the battery 200. The controller 130 can calculate the charge capacity corresponding to each of multiple cycles. According to the embodiment, the controller 130 can calculate the charge capacity of the battery 200 based on current information and charging time corresponding to each of multiple charge-discharge cycles of the battery 200.

[0038] The controller 130 can calculate the discharge capacity of the battery 200. The controller 130 can calculate the discharge capacity corresponding to each of multiple cycles. According to the embodiment, the controller 130 can calculate the discharge capacity of the battery 200 based on current information and discharge time corresponding to each of multiple charge-discharge cycles of the battery 200.

[0039] The controller 130 can compare the charge capacity and the discharge capacity. The controller 130 can compare the charge capacity and the discharge capacity obtained based on the same cycle among multiple charge-discharge cycles. According to the embodiment, the controller 130 can calculate the difference between the charge capacity and the discharge capacity for comparison. This allows the controller 130 to diagnose the state of the battery 200 based on the difference between the charge capacity and the discharge capacity, but is not limited to this. According to the embodiment, the controller 130 can also calculate the ratio of the charge capacity to the discharge capacity for comparison and diagnose the state of the battery 200 based on the ratio of the charge capacity to the discharge capacity.

[0040] The controller 130 can compare the charge OCV and the discharge OCV. The controller 130 can compare the charge OCV and the discharge OCV corresponding to each of multiple charge-discharge cycles. According to the embodiment, the controller 130 can calculate the difference between the charge OCV and the discharge OCV for comparison. This allows the controller 130 to obtain the difference between the charge OCV and the discharge OCV corresponding to each of multiple charge-discharge cycles.

[0041] The controller 130 can calculate the change in charge OCV. The controller 130 can calculate the change in charge OCV by comparing the charge OCVs corresponding to each of multiple charge-discharge cycles. For example, the controller 130 can calculate the change in charge OCV by comparing the first charge OCV, second charge OCV, and third charge OCV corresponding to sequentially consecutive first, second, and third cycles. The controller 130 can calculate the change in charge OCV corresponding to the second cycle based on the value obtained by subtracting the first charge OCV from the second charge OCV. The controller 130 can also calculate the change in charge OCV corresponding to the third cycle based on the value obtained by subtracting the second charge OCV from the third charge OCV.

[0042] The controller 130 can calculate the change in discharge OCV. The controller 130 can calculate the change in discharge OCV by comparing the discharge OCVs corresponding to each of multiple charge-discharge cycles. For example, the controller 130 can calculate the change in discharge OCV by comparing the first discharge OCV, second discharge OCV, and third discharge OCV corresponding to sequentially consecutive first, second, and third cycles. The controller 130 can calculate the change in discharge OCV corresponding to the second cycle based on the value obtained by subtracting the first discharge OCV from the second discharge OCV. The controller 130 can also calculate the change in discharge OCV corresponding to the third cycle based on the value obtained by subtracting the second discharge OCV from the third discharge OCV.

[0043] The controller 130 can determine the state of the battery 200. The controller 130 can determine the state of the battery 200 based on the charge capacity, discharge capacity, charge OCV, and discharge OCV. The operation by which the controller 130 determines the state of the battery 200 will be described in detail later with reference to Figures 3 to 5.

[0044] Figure 3 is a graph showing how a battery diagnostic device according to one embodiment disclosed in this document diagnoses a short circuit or lithium deposition inside a battery. Figure 4 is a graph showing how a battery diagnostic device according to one embodiment disclosed in this document diagnoses a battery fire hazard condition. Figure 5 is a graph showing how a battery diagnostic device according to one embodiment disclosed in this document considers changes in charge OCV and discharge OCV to diagnose a battery fire hazard condition.

[0045] Referring to Figure 3, the controller 130 can compare the charge capacity and discharge capacity corresponding to each of multiple cycles. For example, the controller 130 can calculate the difference between the charge capacity and discharge capacity corresponding to each of multiple cycles.

[0046] The controller 130 can compare the difference between the charging capacity and the discharging capacity with a first reference value. Here, the first reference value may be a value that has already been set to detect the change in the discharging capacity relative to the charging capacity.

[0047] The controller 130 can compare the difference between the charge capacity and discharge capacity for each of the multiple charge-discharge cycles with a first reference value. This allows the controller 130 to determine whether or not the difference between the charge capacity and discharge capacity exceeds the first reference value.

[0048] According to the embodiment, the controller 130 can determine that the state of the battery 200 is abnormal if there is a cycle in which the difference between the charging capacity and the discharging capacity exceeds a first reference value.

[0049] Furthermore, the controller 130 can determine that the battery 200 is in a normal state if, in any of the multiple charge-discharge cycles, there is no cycle in which the difference between the charge capacity and the discharge capacity exceeds the first reference value. In other words, the controller 130 can determine that the battery 200 is in a normal state if the difference between the charge capacity and the discharge capacity in each of the multiple charge-discharge cycles is less than or equal to the first reference value.

[0050] According to the embodiment, the controller 130 can calculate the number of cycles in which the difference between the charge capacity and the discharge capacity exceeds a first reference value. In this case, if the number of cycles in which the difference between the charge capacity and the discharge capacity exceeds the first reference value is equal to or greater than a previously set number, the controller 130 can determine that the state of the battery 200 is abnormal. Here, the previously set number can be set considering the type of battery 200, the total number of charge-discharge cycles, etc. Also, in this case, if the number of cycles in which the difference between the charge capacity and the discharge capacity exceeds the first reference value is less than the previously set number, the controller 130 can determine that the state of the battery 200 is normal.

[0051] If the controller 130 determines that the state of the battery 200 is abnormal, it can determine the detailed state of the battery 200 based on the charge OCV and discharge OCV. According to the embodiment, the controller 130 can calculate the difference between the charge OCV and discharge OCV corresponding to each of multiple charge-discharge cycles.

[0052] The controller 130 can determine that a short circuit or lithium deposition has occurred inside the battery 200 if the difference between the charging OCV and the discharging OCV is greater than or equal to a second reference value. In other words, the controller 130 can determine that a short circuit or lithium deposition has occurred inside the battery 200 if the difference between the charging OCV and the discharging OCV corresponding to each of multiple cycles is greater than or equal to the second reference value. Here, the second reference value can be set considering the difference between the charging OCV and the discharging OCV corresponding to the first cycle of the charge-discharge cycle, the type of battery 200 or charger / discharger, etc.

[0053] According to the embodiment, if the charge OCV and discharge OCV do not change during multiple charge-discharge cycles, the controller 130 can determine that the battery 200 is abnormal and determine that a short circuit or lithium deposition has occurred inside the battery 200.

[0054] Referring to Figure 4, the controller 130 can diagnose the risk of battery 200 ignition. If the controller 130 determines that the state of battery 200 is abnormal, it can determine the detailed state of battery 200 based on the charge OCV and discharge OCV.

[0055] According to the embodiment, the controller 130 can determine that the state of the battery 200 is in a dangerous state if the difference between the charging OCV and the discharging OCV is less than a second reference value. Here, a dangerous state may mean a fire-prone state of the battery 200. In other words, the controller 130 can determine that the state of the battery 200 is in a dangerous state if the charging capacity and discharging capacity of the battery 200 are equal to or greater than a first reference value, and the difference between the charging OCV and the discharging OCV is less than a second reference value.

[0056] According to the embodiment, the controller 130 can calculate the first difference, second difference, and third difference, which are the difference values ​​between the charge OCV and the discharge OCV corresponding to the first, second, and third consecutive charge / discharge cycles of the battery 200, respectively. The controller 130 can also compare the first difference, second difference, and third difference. As a result, if the second difference is smaller than the first difference and the third difference is smaller than the second difference, the controller 130 can determine that the state of the battery 200 is in a dangerous state. In other words, if the charge OCV decreases and the discharge OCV increases over two consecutive cycles, the controller 130 can determine that the state of the battery 200 is in a dangerous state.

[0057] In the diagram, the controller 130 can determine that the difference between the charge OCV and discharge OCV of battery 200 after 40 cycles is smaller than the difference after 39 cycles, and that the difference between the charge OCV and discharge OCV after 41 cycles is smaller than the difference after 40 cycles. As a result, the controller 130 can determine that the state of battery 200 after 41 charge-discharge cycles is in a dangerous state.

[0058] Referring to Figure 5, the controller 130 can calculate the rate of change of the charge OCV and the rate of change of the discharge OCV. Furthermore, the controller 130 can determine the state of the battery 200 based on the changes in the charge OCV and discharge OCV.

[0059] The controller 130 can calculate the rate of change of the charge OCV and the rate of change of the discharge OCV corresponding to each of multiple charge-discharge cycles. For example, the controller 130 can calculate the rate of change of the charge OCV based on the value obtained by subtracting the charge OCV of the previous cycle from the charge OCV of the current cycle. The controller 130 can also calculate the rate of change of the discharge OCV based on the value obtained by subtracting the discharge OCV of the previous cycle from the discharge OCV of the current cycle.

[0060] In the case of a normal battery 200, the charge OCV and discharge OCV are maintained constant within the margin of error, so the rate of change in charge OCV and discharge OCV due to charge-discharge cycles can be 0.

[0061] According to the embodiment, the controller 130 can determine whether the rate of change of the charging OCV falls outside a previously set range. The controller 130 can also determine whether the rate of change of the discharging OCV falls outside a previously set range. Here, the previously set range can be set considering the type of battery 200, the type of charger / discharger, or the error range, etc.

[0062] According to the embodiment, the controller 130 can determine that the state of the battery 200 is in a dangerous state if the rate of change of the charge OCV falls outside a previously set range. Furthermore, the controller 130 can determine that a short circuit or lithium deposition has occurred inside the battery 200 if the rate of change of the charge OCV is within a previously set range.

[0063] According to the embodiment, the controller 130 can determine that the state of the battery 200 is in a dangerous state if the rate of change of the discharge OCV falls outside a previously set range. Furthermore, the controller 130 can determine that a short circuit or lithium deposition has occurred inside the battery 200 if the rate of change of the discharge OCV is within a previously set range.

[0064] According to the embodiment, the controller 130 can determine that the state of the battery 200 is in a dangerous state if both the rate of change of the charging OCV and the rate of change of the discharging OCV fall outside a previously set range. Furthermore, the controller 130 can determine that a short circuit or lithium deposition has occurred inside the battery 200 if at least one of the rate of change of the charging OCV and the rate of change of the discharging OCV is within a previously set range.

[0065] In the diagram, the controller 130 can determine that the rate of change of the charge OCV and the rate of change of the discharge OCV are within the already set range for the first 0 to 36 charge / discharge cycles, and that at cycle 37 the rate of change of the charge OCV and the rate of change of the discharge OCV fall outside the already set range. As a result, the controller 130 can determine that the state of the battery 200 is in a dangerous state at cycle 37 of the multiple charge / discharge cycles.

[0066] In other words, the controller 130 can determine that the state of the battery 200 is in a dangerous state if, as the charge-discharge cycle is repeated, the charge OCV decreases sequentially, the discharge OCV increases sequentially, the rate of change of the charge OCV is below a set range, and the rate of change of the discharge OCV is above a set range.

[0067] If the diagnosis confirms that the battery 200 is abnormal, the controller 130 can provide the user with information about the abnormal battery 200. For example, the controller 130 can provide information about the abnormal battery 200 to the user terminal via a communication unit (not shown), or it can provide information about the abnormal battery 200 via a display installed in the vehicle or charger, etc.

[0068] The battery diagnostic device 100 can diagnose the condition of the battery 200 based on its charge capacity, discharge capacity, charge OCV, and discharge OCV. This allows the battery diagnostic device 100 to improve the accuracy of diagnosing the condition of the battery 200.

[0069] The battery diagnostic device 100 can first diagnose the state of the battery 200 based on its charge capacity and discharge capacity, and secondarily diagnose batteries 200 identified as abnormal based on their charge OCV and discharge OCV. This allows the battery diagnostic device 100 to categorize the state of the battery 200 into one of three categories: normal, short-circuit or lithium deposition, or fire hazard. This enables the battery diagnostic device 100 to provide the user with a detailed breakdown of the battery 200's state, allowing the user to efficiently address abnormal batteries 200.

[0070] Furthermore, the battery diagnostic device 100 notifies the user in advance of any fire hazards in the battery 200 based on its diagnosis, allowing the user to prevent a fire in the battery 200.

[0071] Figure 6 is a flowchart showing a diagnostic method for a battery 200 according to one embodiment disclosed in this document. The embodiment shown in Figure 6 is only one embodiment, and the sequence of operations in various embodiments of the present invention may differ from that shown in Figure 6. Some of the steps shown in Figure 6 may be omitted, the order of the steps may be changed, or steps may be merged.

[0072] Referring to Figure 6, the method for diagnosing the battery 200 may include the following: an operation (S100) to calculate the charge capacity, discharge capacity, charge OCV, and discharge OCV of the battery 200; an operation (S200) to calculate the difference between the charge capacity and the discharge capacity and the difference between the charge OCV and the discharge OCV; and an operation (S300) to determine the state of the battery 200.

[0073] The operations S100 to S300 will be explained in detail below with reference to Figures 1 to 5. In operation S100, the battery diagnostic device 100 can calculate the charge capacity, discharge capacity, charge OCV, and discharge OCV of the battery 200.

[0074] The battery diagnostic device 100 can acquire information about the battery 200. According to the embodiment, the battery diagnostic device 100 can acquire voltage information and current information of the battery 200. For example, the battery diagnostic device 100 can acquire voltage and current corresponding to each of multiple charge-discharge cycles of the battery 200. In particular, the battery diagnostic device 100 can measure the voltage at the end of the charge cycle and the voltage at the end of the discharge cycle included in each charge-discharge cycle. Here, the voltage at the end of the charge cycle of the battery 200 can be defined as the charge OCV (Open Circuit Voltage). Also, the voltage at the end of the discharge cycle of the battery 200 can be defined as the discharge OCV.

[0075] The battery diagnostic device 100 can calculate the charge capacity of the battery 200. The battery diagnostic device 100 can calculate the charge capacity corresponding to each of multiple cycles. According to the embodiment, the battery diagnostic device 100 can calculate the charge capacity of the battery 200 based on current information and charging time corresponding to each of multiple charge-discharge cycles of the battery 200.

[0076] The battery diagnostic device 100 can calculate the discharge capacity of the battery 200. The battery diagnostic device 100 can calculate the discharge capacity corresponding to each of multiple cycles. According to the embodiment, the battery diagnostic device 100 can calculate the discharge capacity of the battery 200 based on current information and discharge time corresponding to each of multiple charge-discharge cycles of the battery 200.

[0077] In operation S200, the battery diagnostic device 100 can calculate the difference between the charging capacity and the discharging capacity, and the difference between the charging OCV and the discharging OCV. The battery diagnostic device 100 can compare the charge capacity and the discharge capacity. The battery diagnostic device 100 can compare the charge capacity and the discharge capacity obtained based on the same cycle among multiple charge-discharge cycles. According to one embodiment, the battery diagnostic device 100 can calculate the difference between the charge capacity and the discharge capacity for comparison. This allows the battery diagnostic device 100 to diagnose the state of the battery 200 based on the difference between the charge capacity and the discharge capacity, but is not limited to this. According to another embodiment, the battery diagnostic device 100 can also calculate the ratio of the charge capacity to the discharge capacity for comparison and diagnose the state of the battery 200 based on the ratio of the charge capacity to the discharge capacity.

[0078] The battery diagnostic device 100 can compare the charge OCV and the discharge OCV. The battery diagnostic device 100 can compare the charge OCV and the discharge OCV corresponding to each of multiple charge-discharge cycles. According to the embodiment, the battery diagnostic device 100 can calculate the difference between the charge OCV and the discharge OCV for comparison. This allows the battery diagnostic device 100 to obtain the difference between the charge OCV and the discharge OCV corresponding to each of multiple charge-discharge cycles.

[0079] In operation S300, the battery diagnostic device 100 can determine the status of the battery 200. The battery diagnostic device 100 can determine the state of the battery 200 based on its charge capacity, discharge capacity, charge OCV, and discharge OCV. This will be explained later with reference to Figure 7.

[0080] Figure 7 is a flowchart that specifically shows the operation for determining the state of battery 200 in Figure 6. In operation S310, the battery diagnostic device 100 can determine whether the difference between the charging capacity and the discharging capacity exceeds a first reference value.

[0081] The battery diagnostic device 100 can compare the difference between the charging capacity and the discharging capacity with a first reference value. Here, the first reference value may be a value that has already been set to detect the change in discharging capacity relative to the charging capacity.

[0082] The battery diagnostic device 100 can compare the difference between the charge capacity and discharge capacity for each of several charge-discharge cycles with a first reference value. This allows the battery diagnostic device 100 to determine whether the difference between the charge capacity and discharge capacity exceeds the first reference value.

[0083] If the difference between the charging capacity and the discharging capacity exceeds the first reference value, the battery diagnostic device 100 can perform operation S320. If the difference between the charging capacity and the discharging capacity is less than or equal to the first reference value, the battery diagnostic device 100 can perform operation S330.

[0084] In operation S320, the battery diagnostic device 100 can determine whether the difference between the charge OCV and the discharge OCV is less than the second reference value. If the battery diagnostic device 100 determines that the state of the battery 200 is abnormal, it can determine the detailed state of the battery 200 based on the charge OCV and discharge OCV. According to the embodiment, the battery diagnostic device 100 can calculate the difference between the charge OCV and discharge OCV corresponding to each of multiple charge-discharge cycles.

[0085] The battery diagnostic device 100 can compare the difference between the charging OCV and the discharging OCV with a second reference value. If the difference between the charging OCV and the discharging OCV is greater than or equal to the second reference value, the battery diagnostic device 100 can perform operation S340. If the difference between the charging OCV and the discharging OCV is less than the second reference value, the battery diagnostic device 100 can perform operation S350.

[0086] In operation S330, the battery diagnostic device 100 can determine that the state of the battery 200 is normal. According to this embodiment, the battery diagnostic device 100 does not have to provide the user with any further notification, but is not limited to this. For example, the battery diagnostic device 100 can also provide the user with a notification that the battery 200 is in a normal state.

[0087] In operation S340, the battery diagnostic device 100 can determine that a short circuit or lithium deposition has occurred inside the battery 200. Specifically, the battery diagnostic device 100 can determine that a short circuit or lithium deposition has occurred inside the battery 200 if the difference between the charge capacity and the discharge capacity exceeds the first reference value, and the difference between the charge OCV and the discharge OCV is equal to or greater than the second reference value.

[0088] In operation S350, the battery diagnostic device 100 can determine that the state of the battery 200 is in a dangerous state. Specifically, the battery diagnostic device 100 can determine that the state of the battery 200 is in a dangerous state if the difference between the charge capacity and the discharge capacity exceeds the first standard value, and the difference between the charge OCV and the discharge OCV is less than the second standard value.

[0089] In operation S360, the battery diagnostic device 100 can provide the user with a notification of a short circuit or lithium deposition. In operation S370, the battery diagnostic device 100 can provide the user with a notification of a dangerous condition.

[0090] Figure 8 shows a computing system that performs a battery diagnostic method according to one embodiment disclosed in this document. Referring to Figure 8, the computing system 300 according to one embodiment disclosed in this document may include an MCU 310, a memory 320, an input / output I / F 330, and a communication I / F 340.

[0091] The MCU310 may be a processor that executes various programs stored in the memory 320 (for example, a program for calculating SOH, a program for determining which cells to perform cell balancing, etc.), processes various data including SOC and SOH of multiple battery cells through such programs, and performs the functions of the battery diagnostic device 100 described above with reference to Figures 1 to 7.

[0092] Memory 320 can store various programs related to calculating the State of Health (SOH) of battery cells and determining which cells are to be subjected to cell balancing. Memory 320 can also store various data, such as the State of Charge (SOC) and SOH data for each battery cell.

[0093] Multiple such memory 320s may be provided as needed. The memory 320 may be volatile or non-volatile. As volatile memory, RAM, DRAM, SRAM, etc., can be used. As non-volatile memory, ROM, PROM, EAROM, EPROM, EEPROM, flash memory, etc., can be used. The examples of memory 320 listed above are merely illustrative and the system is not limited to these examples.

[0094] The input / output interface 330 can provide an interface that connects input devices (not shown), such as keyboards, mice, and touch panels, with output devices (not shown), such as displays, and the MCU 310, enabling data transmission and reception.

[0095] The communication interface 340 is configured to send and receive various data with the server and may be various devices that support wired or wireless communication. For example, programs for calculating the state of health (SOH) of battery cells and determining which cells are to be balanced, as well as various other data, can be sent and received from a separately provided external server via the communication interface 340. Thus, the battery management method according to one embodiment disclosed in this document can be recorded in the memory 320 and executed by the MCU 310.

[0096] The above description is merely illustrative of the technical concept disclosed in this document, and any person with ordinary skill in the art to which the embodiments disclosed in this document belong can make various modifications and variations without departing from the essential characteristics of the embodiments disclosed in this document.

[0097] Therefore, the embodiments disclosed herein are for illustrative purposes only, not to limit, the technical ideas disclosed herein, and such embodiments do not limit the scope of the technical ideas disclosed herein. The scope of protection for the technical ideas disclosed herein must be interpreted according to the claims described below, and all technical ideas within an equivalent scope should be interpreted as being included in the scope of rights of this document.

Claims

1. An information acquisition unit that measures the voltage and current of the battery, Based on the voltage and current, the charging capacity and discharging capacity of the battery are calculated. A controller that diagnoses the battery based on the charging capacity, the discharging capacity, and the difference between the charging OCV and the discharging OCV, Battery diagnostic device, including

2. The controller calculates the difference between the charging capacity and the discharging capacity, The battery diagnostic device according to claim 1, which determines that the battery is abnormal if the difference between the charging capacity and the discharging capacity exceeds a first reference value.

3. The battery diagnostic device according to claim 2, wherein the controller determines the battery to be in a dangerous state when the difference between the charge OCV and the discharge OCV is less than a second reference value.

4. The controller calculates the first difference, second difference, and third difference, which are the difference values ​​between the charging OCV and the discharging OCV, for the first, second, and third consecutive charge-discharge cycles of the battery, respectively. The battery diagnostic device according to claim 3, wherein if the second difference is smaller than the first difference and the third difference is smaller than the second difference, the state of the battery is determined to be in a dangerous state.

5. The controller calculates the rate of change of the discharge OCV, The battery diagnostic device according to claim 3, wherein if the rate of change of the discharge OCV falls outside a previously set range, the state of the battery is determined to be in a dangerous state.

6. The controller calculates the rate of change of the charge OCV, The battery diagnostic device according to claim 3, wherein if the rate of change of the charge OCV falls outside a previously set range, the state of the battery is determined to be in a dangerous state.

7. The battery diagnostic device according to any one of claims 2 to 6, wherein the controller determines that a short circuit or lithium deposition has occurred inside the battery when the rate of change of the charge OCV and the rate of change of the discharge OCV are within a range that has already been set.

8. The battery diagnostic device according to any one of claims 1 to 6, wherein the controller determines the state of the battery to be normal when the difference between the charging capacity and the discharging capacity is less than or equal to a first reference value.

9. The operation of obtaining the battery's charge capacity, discharge capacity, charge OCV, and discharge OCV, The operation of calculating the difference between the charging capacity and the discharging capacity and the difference between the charging OCV and the discharging OCV, An operation to determine the state of the battery based on the difference between the charging capacity and the discharging capacity and the difference between the charging OCV and the discharging OCV, Battery diagnostic methods, including those mentioned above.

10. The operation to determine the state of the battery is: The battery diagnostic method according to claim 9, wherein the operation determines that the state of the battery is normal when the difference between the charging capacity and the discharging capacity is less than or equal to a first reference value.

11. The operation to determine the state of the battery is: The battery diagnostic method according to claim 9, further comprising the operation of determining whether the difference between the charging OCV and the discharging OCV is less than a second reference value when the difference between the charging capacity and the discharging capacity exceeds a first reference value.

12. The operation to determine the state of the battery is: The battery diagnostic method according to claim 11, further comprising the operation of determining the state of the battery to be in a dangerous state when the difference between the charge OCV and the discharge OCV is less than a second reference value.

13. The operation to determine the state of the battery is: For each of the multiple charge-discharge cycles of the battery, the first difference, second difference, and third difference are calculated, which are the difference values ​​between the charge OCV and the discharge OCV corresponding to the first, second, and third consecutive cycles, respectively. The battery diagnostic method according to claim 11, further comprising the operation of determining the state of the battery to be in a dangerous state if the second difference is smaller than the first difference and the third difference is smaller than the second difference.

14. The operation to determine the state of the battery is: The battery diagnostic method according to claim 11, further comprising the operation of determining that a short circuit or lithium deposition has occurred inside the battery when the difference between the charging OCV and the discharging OCV is equal to or greater than a second reference value.

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