Battery diagnostic device and method

Abstract

A battery diagnostic device according to an embodiment of the present invention includes: a data acquisition unit configured to acquire battery information including a voltage and a current of the battery during a charging cycle of the battery; and a control unit configured to calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio during the charging cycle based on the battery information, and to diagnose a state of the battery based on the constant current charging capacity ratio and the constant voltage charging capacity ratio.

Description

[Technical Field]

[0001] This application claims priority based on Korean Patent Application No. 10-2022-0144059, filed on November 1, 2022, and the entire contents disclosed in the specification and drawings of that application are incorporated herein by reference.

[0002] The present invention relates to a battery diagnostic device and method, and more particularly to a battery diagnostic device and method capable of diagnosing the state of a battery in a non-destructive manner. [Background technology]

[0003] In recent years, as demand for portable electronic products such as laptops, video cameras, and mobile phones has grown rapidly and the development of electric vehicles, energy storage batteries, robots, and artificial satellites has gained momentum, active research has been conducted into high-performance batteries that can be repeatedly charged and discharged.

[0004] Currently commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. Among these, lithium batteries are attracting attention due to their advantages of being able to be freely charged and discharged since they have almost no memory effect compared to nickel-based batteries, as well as their extremely low self-discharge rate and high energy density.

[0005] These batteries deteriorate with repeated charging and discharging. For example, gas generation can reduce the electron transfer ability within the electrodes, leading to imbalance in negative electrode deterioration. Furthermore, gas generation in batteries can lead to fire, so if battery status is not diagnosed promptly, unexpected accidents may occur. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been devised to solve the above problems, and an object of the present invention is to provide a battery diagnostic apparatus and method that can diagnose the state of a battery in a non-destructive manner through profile analysis.

[0007] Other objects and advantages of the present invention will become apparent from the following description and the embodiments of the present invention, and can be realized by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0008] According to one aspect of the present invention, a battery diagnostic device includes: a data acquisition unit configured to acquire battery information including a voltage and a current of the battery during a charging cycle of the battery; and a control unit configured to calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio during the charging cycle based on the battery information, and to diagnose a state of the battery based on the constant current charging capacity ratio and the constant voltage charging capacity ratio.

[0009] The control unit may be configured to divide the total charging capacity in the charging cycle into a constant current charging capacity and a constant voltage charging capacity, and to calculate the constant current charging capacity ratio and the constant voltage charging capacity ratio based on the total charging capacity, the constant current charging capacity, and the constant voltage charging capacity, respectively.

[0010] The control unit may be configured to diagnose the state of the battery based on an increase or decrease in the constant current charging capacity ratio and the constant voltage charging capacity ratio.

[0011] The control unit may be configured to diagnose the state of the battery as a negative electrode stabilized state when the constant current charging capacity ratio increases and the constant voltage charging capacity ratio decreases.

[0012] The control unit may be configured to maintain a charge cutoff condition for the battery when the state of the battery is diagnosed as the negative electrode stabilized state.

[0013] The control unit may be configured to calculate the constant current charge capacity ratio and the constant voltage charge capacity ratio when a total charge capacity of the battery decreases during a charge cycle of the battery.

[0014] The control unit may be configured to compare a total charge capacity of a previous charge cycle with a total charge capacity of a current charge cycle, and determine whether to calculate the constant current charge capacity ratio and the constant voltage charge capacity ratio based on a comparison result.

[0015] The control unit may be configured to compare a total charge capacity of the previous charge cycle with a total charge capacity of the current charge cycle when the current charge cycle of the battery is included in a preset reference cycle section.

[0016] A battery pack according to another aspect of the present invention includes the battery diagnostic device according to an aspect of the present invention.

[0017] According to yet another aspect of the present invention, a battery diagnostic method includes: a battery information acquiring step of acquiring battery information including a voltage and a current of the battery during a charging cycle of the battery; a charging capacity ratio calculating step of calculating a constant current charging capacity ratio and a constant voltage charging capacity ratio during the charging cycle based on the battery information; and a battery status diagnosing step of diagnosing a status of the battery based on the constant current charging capacity ratio and the constant voltage charging capacity ratio. [Effects of the Invention]

[0018] According to one aspect of the present invention, the state of a battery can be diagnosed in a non-destructive manner through profile analysis. In particular, the state of a battery can be specifically diagnosed using a constant current charge capacity ratio and a constant voltage charge capacity ratio of the battery.

[0019] The effects of the present invention are not limited to the effects described above, and other effects of the present invention not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0020] The following drawings attached to this specification, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention, and the present invention should not be interpreted as being limited to only the matters described in the drawings. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a diagram illustrating a battery diagnostic device according to an embodiment of the present invention; [Figure 2] FIG. 10 is a diagram illustrating a total charge capacity profile according to an embodiment of the present invention. [Figure 3] FIG. 2 is a schematic diagram illustrating a constant current charging capacity rate profile according to an embodiment of the present invention. [Figure 4] FIG. 10 is a schematic diagram illustrating a constant voltage charge capacity rate profile according to an embodiment of the present invention. [Figure 5] FIG. 10 is a diagram illustrating a constant current charging capacity rate profile according to another embodiment of the present invention. [Figure 6] FIG. 10 is a diagram illustrating a constant voltage charge capacity rate profile according to another embodiment of the present invention. [Figure 7] FIG. 10 is a diagram schematically illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention. [Figure 8] 10 is a diagram illustrating a battery diagnostic method according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The terms and words used in this specification and claims should not be interpreted limited to their ordinary and dictionary meanings, but should be interpreted in a meaning and concept that corresponds to the technical idea of ​​the present invention, in accordance with the principle that the inventor himself can appropriately define the concept of the term in order to explain the invention in the best way.

[0023] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted for them at the time of this application.

[0024] Furthermore, in the description of the present invention, if it is determined that a detailed description of related known structures or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0025] Terms including ordinal numbers such as "first," "second," etc. are used to distinguish one of various components from other components, and do not limit the components.

[0026] Throughout this specification, when a part is said to "comprise" a certain element, this does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified.

[0027] Furthermore, throughout this specification, when a part is referred to as being "connected" to another part, this includes not only a "direct connection" but also an "indirect connection" via other elements.

[0028] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0029] FIG. 1 is a diagram illustrating a battery diagnostic device 100 according to an embodiment of the present invention.

[0030] Referring to FIG. 1, a battery diagnostic device 100 includes a data acquisition unit 110 and a control unit 120.

[0031] Here, a battery refers to a physically separable, independent cell having a negative terminal and a positive terminal. For example, a lithium ion battery or a lithium polymer battery may be considered a battery. A battery may also refer to a battery module or a battery pack in which multiple cells are connected in series and / or parallel. Hereinafter, for convenience of explanation, a battery will be described as meaning a single independent cell.

[0032] The data acquisition unit 110 may acquire battery information including the voltage and current of the battery during a charging cycle. For example, the data acquisition unit 110 may acquire battery information including the voltage and current of the battery measured during the charging process of the battery.

[0033] Here, the battery charging process can include constant current (CC) charging and constant voltage (CV) charging. Note that for the sake of convenience, the terms constant current charging and CC charging, and constant voltage charging and CV charging will be used interchangeably below.

[0034] Here, a battery refers to a single independent cell that has a negative terminal and a positive terminal and can be physically separated. As an example, a single lithium ion cell or lithium polymer cell may be considered a battery. A battery may also refer to a battery module in which multiple cells are connected in series and / or parallel. A battery may also refer to a battery pack in which multiple battery modules are connected in series and / or parallel. For convenience of explanation, a battery will be described below as referring to a single cell.

[0035] According to the embodiment, the data acquisition unit 110 may acquire battery information measured through a voltage sensing line connected to the positive and negative electrodes of the battery. The data acquisition unit 110 may also be connected to a current sensor that measures the current of the battery. The data acquisition unit 110 may also acquire battery information from the current sensor through the current sensing line.

[0036] The data acquisition unit 110 may acquire battery information including the voltage and current of the battery in real time during the charging cycle of the battery.

[0037] According to an embodiment, the data acquisition unit 110 may be configured to be able to communicate with an external device, and may receive battery information from an external device via communication.

[0038] The control unit 120 and the data acquisition unit 110 may be connected to each other via a wired and / or wireless connection so that they can communicate with each other. The control unit 120 may receive battery information from the data acquisition unit 110 via a wired line and / or a wireless communication network.

[0039] The control unit 120 may calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio during a charging cycle based on the battery information acquired from the data acquisition unit 110 .

[0040] A charge cycle may refer to charging a battery from the lower limit to the upper limit of a preset charge voltage range while maintaining a constant battery temperature, and then interrupting the charging. A charge cycle may be included in a charge / discharge cycle together with a discharge cycle. A discharge cycle may refer to stabilizing the battery for a predetermined time after completing a charge cycle, then discharging the battery from the upper limit to the lower limit of a preset discharge voltage range while maintaining the battery temperature in the same manner as in the charge cycle, and then interrupting the discharging. The charge voltage range and the discharge voltage range may be the same or different. However, when performing multiple charge / discharge cycles, it is preferable that the charge voltage ranges of the charge cycles are the same, and that the discharge voltage ranges of the discharge cycles are also the same.

[0041] As another example, a charge cycle refers to charging a battery from the lower limit to the upper limit of a predetermined charge voltage range while maintaining a constant battery temperature, and then interrupting the charge. A discharge cycle refers to starting discharge from the upper limit of a predetermined discharge voltage range, integrating the discharge current, and interrupting the discharge when the integrated current value reaches a predetermined discharge capacity. When performing multiple charge / discharge cycles, it is preferable that the charge voltage ranges of the charge cycles are the same and the discharge capacities of the discharge cycles are the same.

[0042] The control unit 120 may calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio during the charging cycle.

[0043] Specifically, the control unit 120 may be configured to divide the total charging capacity in a charging cycle into a constant current charging capacity and a constant voltage charging capacity, and may be configured to calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio based on the total charging capacity, the constant current charging capacity, and the constant voltage charging capacity.

[0044] Here, the constant current charging capacity may refer to the capacity charged by constant current charging, and the constant voltage charging capacity may refer to the capacity charged by constant voltage charging.

[0045] For example, the control unit 120 may calculate the constant current charging capacity ratio by calculating the ratio of the constant current charging capacity to the total charging capacity in a charging cycle. Also, the control unit 120 may calculate the constant voltage charging capacity ratio by calculating the ratio of the constant voltage charging capacity to the total charging capacity.

[0046] According to an embodiment, the control unit 120 may receive information about the total charge capacity, the constant current charge capacity, and the constant voltage charge capacity measured during the CC-CV charging process of the battery. In this case, the control unit 120 may calculate a constant current charge capacity ratio and a constant voltage charge capacity ratio based on the received information.

[0047] The control unit 120 may determine the state of the battery based on the constant current charging capacity ratio and the constant voltage charging capacity ratio.

[0048] Specifically, the control unit 120 may diagnose the battery state as a negative electrode stabilized state or a degraded state. For example, a degraded state refers to a state in which the battery has degraded and its SOH (State of Health) is lower than the initial state. Furthermore, a negative electrode stabilized state refers to a state in which the negative electrode of the battery is stabilized. For example, the stabilized state mainly occurs in the initial cycles when the battery begins to be used, and refers to a state in which the reaction area of ​​the negative electrode increases as the active material contracts and expands during initial charge and discharge. In other words, the stabilized state is a state that occurs in a normal battery and can be distinguished from a degraded state.

[0049] 2 is a diagram illustrating a total charge capacity profile according to an embodiment of the present invention. Fig. 2 shows an X-Y two-dimensional graph, where X represents the charge cycle and Y represents the total charge capacity. Referring to the total charge capacity profile in Fig. 2, it can be seen that the total charge capacity decreases linearly as the number of charge cycles increases.

[0050] Generally, the more a battery deteriorates (the more charge cycles it has), the more its total charge capacity may decrease. However, the total charge capacity may also decrease if the battery is in a negative electrode stabilization state during the initial cycle of the battery. That is, if the battery is in a deteriorated state or a negative electrode stabilization state, the total charge capacity may decrease.

[0051] That is, the battery diagnostic device 100 according to an embodiment of the present invention has an advantage in that it can specifically classify and diagnose the state of the battery as a deteriorated state or a negative electrode stabilized state using a non-destructive method.

[0052] Meanwhile, the control unit 120 included in the battery diagnostic device 100 may selectively include a processor, an ASIC (Application-Specific Integrated Circuit), other chipsets, logic circuits, registers, a communication modem, a data processing device, etc., known in the art, to execute various control logics performed in the present invention. Furthermore, when the control logic is embodied as software, the control unit 120 may be embodied as a collection of program modules. In this case, the program modules may be stored in a memory and executed by the control unit 120. The memory may be provided inside or outside the control unit 120 and may be connected to the control unit 120 by various known means.

[0053] The battery diagnostic device 100 may further include a recording unit 130. The recording unit 130 may store data and programs necessary for each component of the battery diagnostic device 100 to operate and function, or data generated during the operation and function. The recording unit 130 may be any known information recording means capable of recording, erasing, updating, and reading data. For example, the information recording means may include RAM, flash memory, ROM, EEPROM, registers, etc. The recording unit 130 may also store program code defining processes executable by the control unit 120.

[0054] The control unit 120 may divide the total charging capacity in a charging cycle into a constant current charging capacity and a constant voltage charging capacity.

[0055] For example, the control unit 120 may classify the capacity charged by constant current charging among the total charging capacity as a constant current charging capacity, and may classify the capacity charged by constant voltage charging among the total charging capacity as a constant voltage charging capacity.

[0056] The control unit 120 may calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio based on the total charging capacity, the constant current charging capacity, and the constant voltage charging capacity.

[0057] For example, the control unit 120 may calculate the constant current charging ratio by comparing the constant current charging capacity with the total charging capacity. Specifically, the control unit 120 may calculate the ratio of the constant current charging capacity to the total charging capacity in a charging cycle to calculate the constant current charging capacity ratio. The control unit 120 may also calculate the ratio of the constant voltage charging capacity to the total charging capacity to calculate the constant voltage charging capacity ratio.

[0058] Furthermore, the control unit 120 may be configured to diagnose the state of the battery based on the increase or decrease of the constant current charging capacity ratio and the constant voltage charging capacity ratio.

[0059] Preferably, the control unit 120 may diagnose the battery state by taking into consideration both the increase and decrease in the constant current charging capacity ratio and the increase and decrease in the constant voltage charging capacity ratio.

[0060] For example, if the constant current charging capacity ratio increases and the constant voltage charging capacity ratio decreases, the control unit 120 may diagnose the battery state as a negative electrode stabilized state.

[0061] As another example, if the constant current charging capacity ratio decreases and the constant voltage charging capacity ratio increases, the control unit 120 may diagnose the battery state as being in a degraded state.

[0062] Figure 3 is a schematic diagram illustrating a constant current charge capacity ratio profile according to an embodiment of the present invention, showing an X-Y two-dimensional graph where X represents the charge cycle and Y represents the constant current charge capacity ratio.

[0063] Referring to FIG. 3, it can be seen that the constant current charge capacity ratio increases linearly with the increase in cycles, and then decreases sharply at a certain point A.

[0064] Figure 4 is a schematic diagram illustrating a constant voltage charge capacity ratio profile according to an embodiment of the present invention, showing an X-Y two-dimensional graph in which X represents the charge cycle and Y represents the constant voltage charge capacity ratio.

[0065] Referring to FIG. 4, it can be seen that the constant voltage charge capacity ratio shows a linear decrease as the number of cycles increases, and then suddenly increases at a specific point A.

[0066] Preferably, the specific point A in Figure 3 and the specific point A in Figure 4 may represent the same charging cycle. For example, the specific point A in Figure 3 and the specific point A in Figure 4 may represent 30 cycles.

[0067] 3 and 4, it can be seen that the constant current charge capacity ratio increases and the constant voltage charge capacity ratio decreases in the charge cycles before a specific point A. Therefore, the control unit 120 may diagnose the battery state as a negative electrode stabilized state in the charge cycles before the specific point A.

[0068] Conversely, it can be seen that the constant current charging capacity ratio decreases and the constant voltage charging capacity ratio increases in charging cycles after the specific point A. Therefore, the control unit 120 may diagnose the battery state as degraded in charging cycles after the specific point A.

[0069] That is, the control unit 120 can diagnose that the state of the battery changes from the negative electrode stable state to the deteriorated state based on a specific point A.

[0070] Preferably, when the total charge capacity of the battery decreases during the charging cycle of the battery, the control unit 120 may be configured to calculate a constant current charge capacity ratio and a constant voltage charge capacity ratio.

[0071] For example, the control unit 120 may compare the total charge capacity of the previous charge cycle with the total charge capacity of the current charge cycle, and determine whether to calculate a constant current charge capacity ratio and a constant voltage charge capacity ratio based on the comparison result.

[0072] As described above, if the total charge capacity decreases, the battery state may be in a degraded state or a negative electrode stabilized state. Therefore, the control unit 120 may be configured to first determine whether the total charge capacity for the battery charge cycle decreases, and then calculate the constant current charge capacity ratio and the constant voltage charge capacity ratio.

[0073] For example, if the total charge capacity decreases, the constant current charge capacity ratio increases, and the constant voltage charge capacity ratio decreases, the control unit 120 may diagnose the battery state as a negative electrode stabilized state.

[0074] As another example, if the total charge capacity decreases, the constant current charge capacity ratio decreases, and the constant voltage charge capacity ratio increases, the control unit 120 may diagnose the battery state as being in a degraded state.

[0075] If the total charge capacity for the charge cycle does not decrease, the actual state of the battery may not be in a negative electrode stabilized state or a deteriorated state even if the constant current charge capacity ratio and the constant voltage charge capacity ratio change. Therefore, in order to efficiently use system resources, the battery diagnostic device 100 may first determine whether the total charge capacity for the charge cycle decreases, and then calculate the constant current charge capacity ratio and the constant voltage charge capacity ratio.

[0076] Meanwhile, when the current charging cycle of the battery is included in the preset reference cycle section R, the control unit 120 may be configured to compare the total charging capacity of the previous charging cycle with the total charging capacity of the current charging cycle.

[0077] As described above, the negative electrode stabilization state may occur primarily in the initial cycles when the battery begins to be used, for example, the negative electrode stabilization state may occur between 1 and 50 cycles.

[0078] Therefore, considering the particularity of the negative electrode stabilization state, the battery diagnostic device 100 can diagnose whether the total charge capacity is decreasing when the current charge cycle of the battery is included in the preset reference cycle section R. Furthermore, the battery diagnostic device 100 can efficiently use system resources by calculating the constant current charge capacity ratio and the constant voltage charge capacity ratio only when the total charge capacity is decreasing.

[0079] 5 is a diagram illustrating a constant current charge capacity ratio profile according to another embodiment of the present invention, specifically, an X-Y two-dimensional graph where X is the charge cycle and Y is the constant current charge capacity ratio.

[0080] 6 is a diagram illustrating a constant voltage charge capacity ratio profile according to another embodiment of the present invention, specifically, an X-Y two-dimensional graph where X is the charge cycle and Y is the constant voltage charge capacity ratio.

[0081] 5 and 6, the 0th to 30th cycles may be preset as a reference cycle section R. That is, within the reference cycle section R, the state of the battery may be diagnosed as a negative electrode stabilized state.

[0082] Referring to Fig. 5, as the number of charge cycles increases in the reference cycle section R, the constant current charge capacity ratio increases. Also, referring to Fig. 6, as the number of charge cycles increases in the reference cycle section R, the constant voltage charge capacity ratio decreases. Therefore, the control unit 120 may diagnose the battery state in the reference cycle section R as a negative electrode stabilized state.

[0083] The control unit 120 may be configured to maintain the charge cutoff condition of the battery when the battery state is diagnosed as a negative electrode stabilization state. As described above, the negative electrode stabilization state is a state that can occur in a normal battery. Therefore, the control unit 120 may not change the charge cutoff condition preset for the battery when the battery state is diagnosed as a negative electrode stabilization state.

[0084] Meanwhile, when the battery state is diagnosed as being in a deteriorated state, the control unit 120 may change the charging cutoff conditions preset for the battery. Preferably, when the battery state is diagnosed as being in a deteriorated state, the control unit 120 may change at least one of the charging cutoff conditions so that charging of the battery can be terminated early.

[0085] For example, the charge cutoff conditions may include conditions regarding the cutoff voltage, cutoff current, cutoff time, and the like.

[0086] The cutoff voltage may refer to the voltage at which CC charging ends. CC charging may be performed until the battery voltage reaches a set cutoff voltage, and CV charging may begin once the battery voltage reaches the cutoff voltage. For example, the control unit 120 may reduce the cutoff voltage if the battery is diagnosed as being in a degraded state. In this case, the usable voltage range of the battery is reduced, thereby limiting the use of the battery at high voltages, thereby preventing or mitigating battery degradation.

[0087] The cutoff current may refer to the current at which CV charging ends. During CV charging of a battery, the battery voltage may be maintained constant corresponding to the cutoff voltage, and the charging current may decrease. Furthermore, when the charging current reaches the cutoff current, charging of the battery may end. For example, if the control unit 120 diagnoses that the battery is in a deteriorated state, it may increase the cutoff current. In this case, increasing the CV charging cutoff current of the battery's charging cycle may reduce the time the battery remains at a high potential.

[0088] The cutoff time may refer to the time required for CV charging. For example, if the battery is diagnosed as being in a degraded state, the control unit 120 may decrease the cutoff time. In this case, charging of the battery may be terminated earlier than before.

[0089] The battery diagnostic device 100 according to an embodiment of the present invention has an advantage in that it can set charging conditions to correspond to the current state of the battery by maintaining or changing the charging cutoff conditions according to the state of the battery being diagnosed. In this way, it is possible to prevent battery deterioration based on the charging conditions set for each charging cycle, thereby increasing the expected lifespan of the battery.

[0090] The battery diagnostic device 100 according to the present invention may be applied to a battery management system (BMS). That is, the BMS according to the present invention may include the above-described battery diagnostic device 100. In this configuration, at least some of the components of the battery diagnostic device 100 may be implemented by complementing or adding functions of components included in a conventional BMS. For example, the data acquisition unit 110, the control unit 120, and the recording unit 130 of the battery diagnostic device 100 may be implemented as components of the BMS.

[0091] FIG. 7 is a diagram schematically illustrating an exemplary configuration of a battery pack 1 according to another embodiment of the present invention.

[0092] The battery diagnostic device 100 according to the present invention may be provided in a battery pack 1. That is, the battery pack 1 according to the present invention may include the above-described battery diagnostic device 100, a measuring unit 20, and one or more batteries 10. The battery pack 1 may further include electrical components (relays, fuses, etc.), a case, etc.

[0093] The positive terminal of the battery 10 may be connected to the positive terminal P+ of the battery pack 1, and the negative terminal of the battery 10 may be connected to the negative terminal P- of the battery pack 1.

[0094] The measuring unit 20 may be connected to a first sensing line SL1, a second sensing line SL2, and a third sensing line SL3. Specifically, the measuring unit 20 may be connected to the positive terminal of the battery 10 via the first sensing line SL1 and to the negative terminal of the battery 10 via the second sensing line SL2. The measuring unit 20 may measure the voltage of the battery 10 based on the voltages measured on the first sensing line SL1 and the second sensing line SL2.

[0095] The measuring unit 20 may also be connected to a current measuring unit A through a third sensing line SL3. For example, the current measuring unit A may be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of the battery 10. The measuring unit 20 may measure the charging current of the battery 10 through the third sensing line SL3 to calculate the charged amount. The measuring unit 20 may also measure the discharging current of the battery 10 through the third sensing line SL3 to calculate the discharged amount.

[0096] The external device 2 may be a charging device or a load connectable to the battery pack 1. Specifically, one end of the external device 2 may be connected to the positive terminal P+ of the battery pack 1, and the other end may be connected to the negative terminal P- of the battery pack 1. Therefore, the positive terminal of the battery 10, the positive terminal P+ of the battery pack 1, the external device 2, the negative terminal P- of the battery pack 1, and the negative terminal of the battery 10 may be electrically connected.

[0097] FIG. 8 is a diagram illustrating a battery diagnostic method according to another embodiment of the present invention.

[0098] Preferably, each step of the battery diagnostic method can be performed by a battery diagnostic device. In the following, the content that overlaps with the above description will be omitted or will be briefly described.

[0099] The battery information acquisition step S100 is a step of acquiring battery information including the voltage and current of the battery during a charging cycle of the battery, and may be performed by the data acquisition unit 110.

[0100] For example, the data acquisition unit 110 may acquire battery information including the voltage and current of the battery during a charging cycle, for example, the data acquisition unit 110 may acquire battery information including the voltage and current of the battery measured during a CC-CV charging process of the battery.

[0101] For example, the data acquisition unit 110 may acquire battery information including the voltage and current of the battery in real time during the charging cycle of the battery.

[0102] The charge capacity ratio calculation step S200 is a step of calculating a constant current charge capacity ratio and a constant voltage charge capacity ratio during a charge cycle based on battery information, and may be performed by the control unit 120.

[0103] For example, the control unit 120 may be configured to divide the total charge capacity in a charge cycle into a constant current charge capacity and a constant voltage charge capacity, and may be configured to calculate a constant current charge capacity ratio and a constant voltage charge capacity ratio based on the total charge capacity, the constant current charge capacity, and the constant voltage charge capacity.

[0104] Specifically, the control unit 120 may calculate the constant current charging capacity ratio by calculating the ratio of the constant current charging capacity to the total charging capacity in the charging cycle, and may calculate the constant voltage charging capacity ratio by calculating the ratio of the constant voltage charging capacity to the total charging capacity.

[0105] Preferably, the control unit 120 may calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio when the total charging capacity of the battery decreases during the charging cycle of the battery.

[0106] More preferably, the control unit 120 may calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio when the current charging cycle of the battery is included in a preset reference cycle section and the total charging capacity of the battery is reduced.

[0107] The battery state diagnosis step S300 is a step of diagnosing the state of the battery based on the constant current charging capacity ratio and the constant voltage charging capacity ratio, and may be performed by the control unit 120.

[0108] For example, if the constant current charging capacity ratio increases and the constant voltage charging capacity ratio decreases, the control unit 120 may diagnose the battery state as a negative electrode stabilized state.

[0109] As another example, if the constant current charging capacity ratio decreases and the constant voltage charging capacity ratio increases, the control unit 120 may diagnose the battery state as being in a degraded state.

[0110] Preferably, when the total charge capacity of the charge cycle decreases, the control unit 120 may diagnose the battery state based on the constant current charge capacity ratio and the constant voltage charge capacity ratio. More preferably, when the current charge cycle of the battery belongs to the reference cycle section and the total charge capacity of the charge cycle decreases, the control unit 120 may diagnose the battery state based on the constant current charge capacity ratio and the constant voltage charge capacity ratio.

[0111] The above-described embodiments of the present invention may be realized not only by an apparatus and a method, but also by a program that realizes functions corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded, and such realization can be easily realized by a person skilled in the art from the description of the above-described embodiments.

[0112] As described above, the present invention has been described using limited embodiments and drawings, but the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims.

[0113] Furthermore, the present invention described above can be variously replaced, modified, and changed by a person having ordinary knowledge in the technical field to which the present invention belongs, within the scope that does not deviate from the technical concept of the present invention, and is not limited to the above-described embodiments and the accompanying drawings, but can be configured by selectively combining all or part of each embodiment to enable various modifications. [Explanation of symbols]

[0114] 1: Battery pack 2: External device 10: Battery 20: Measuring part 100: Battery diagnostic device 110: Data acquisition unit 120: Control unit 130: Recording section

Claims

1. a data acquisition unit configured to acquire battery information including the voltage and current of the battery during a charging cycle of the battery; a control unit configured to calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio during the charging cycle based on the battery information, and to diagnose a state of the battery based on the constant current charging capacity ratio and the constant voltage charging capacity ratio.

2. The control unit 2. The battery diagnostic device according to claim 1, wherein the total charging capacity in the charging cycle is divided into a constant current charging capacity and a constant voltage charging capacity, and the constant current charging capacity ratio and the constant voltage charging capacity ratio are calculated based on the total charging capacity, the constant current charging capacity, and the constant voltage charging capacity, respectively.

3. The control unit 2. The battery diagnostic device according to claim 1, configured to diagnose the state of the battery based on increases and decreases in the constant current charging capacity ratio and the constant voltage charging capacity ratio.

4. The control unit 4. The battery diagnostic device according to claim 3, wherein the battery state is diagnosed as a negative electrode stabilized state when the constant current charging capacity ratio increases and the constant voltage charging capacity ratio decreases.

5. The control unit The battery diagnostic device according to claim 4 , configured to maintain a charge cutoff condition for the battery when the state of the battery is diagnosed as the negative electrode stabilization state.

6. The control unit 4. The battery diagnostic device according to claim 3, wherein the battery is diagnosed as being in a deteriorated state if the constant current charging capacity ratio decreases and the constant voltage charging capacity ratio increases.

7. The control unit 2. The battery diagnostic device according to claim 1, configured to calculate the constant current charge capacity ratio and the constant voltage charge capacity ratio when the total charge capacity of the battery decreases during a charge cycle of the battery.

8. The control unit 8. The battery diagnostic device according to claim 7, which is configured to compare a total charge capacity of a previous charge cycle with a total charge capacity of a current charge cycle, and determine whether to calculate the constant current charge capacity ratio and the constant voltage charge capacity ratio based on a comparison result.

9. The control unit 2. The battery diagnostic device of claim 1, further comprising: a step of: comparing a total charge capacity of a previous charge cycle with a total charge capacity of a current charge cycle when the current charge cycle of the battery is within a predetermined reference cycle interval.

10. A battery pack comprising the battery diagnostic device according to any one of claims 1 to 9.

11. acquiring battery information including a voltage and a current of the battery during a charging cycle of the battery; calculating a constant current charge capacity ratio and a constant voltage charge capacity ratio during the charging cycle based on the battery information; and diagnosing a battery state based on the constant current charging capacity ratio and the constant voltage charging capacity ratio.

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