Battery diagnosis device and method, and battery pack including the same

Abstract

A battery diagnosis device according to an embodiment of the present invention includes: a curve generation unit configured to generate a differential curve representing a correspondence between a voltage of a battery and a differential capacity with respect to the voltage of the battery; and a control unit configured to receive the differential curve from the curve generation unit, determine a target peak from the differential curve, determine a behavior pattern of the target peak based on a reference peak included in a preset reference curve, and compare the behavior pattern determined for the target peak with a plurality of preset behavior types to diagnose a state of a negative electrode of the battery.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2020-0169917, filed in Korea on December 7, 2020, the disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to a battery diagnosis device and method, and more particularly, to a battery diagnosis device and method capable of diagnosing the state of a negative electrode of a battery. Background Art

[0003] Recently, the demand for portable electronic products such as notebook computers, camcorders, and mobile phones has increased rapidly, and electric vehicles, energy storage batteries, robots, satellites, etc. have been seriously developed. Therefore, high-performance batteries that allow repeated charging and discharging are being actively studied.

[0004] Currently commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium batteries, etc. Among them, lithium batteries have attracted much attention because they have almost no memory effect compared to nickel-based batteries and also have an extremely low self-charging rate and high energy density.

[0005] When the battery is being charged, a polarization phenomenon occurs inside the battery. The polarization phenomenon depends on various resistance components of the battery (e.g., ohmic resistance, charge transfer resistance, diffusion resistance). The reason why the battery voltage is higher than the open circuit voltage (OCV) during charging is that an overvoltage (overpotential) is formed due to the polarization phenomenon.

[0006] As the battery deteriorates, the polarization phenomenon tends to intensify. Therefore, even if the charging conditions (e.g., charging current, temperature) are the same, the magnitude of the overvoltage can increase as the degree of battery deterioration increases. If the overvoltage increases excessively, there is a problem of accelerating battery deterioration. For example, during charging, the voltage of the negative electrode of the battery gradually decreases. Here, if the voltage of the negative electrode of the battery drops below 0 V due to the overvoltage, lithium metal rapidly precipitates on the negative electrode, and as a result, the loss amount of lithium ions that can participate in the charge and discharge reaction increases.

[0007] In addition, the negative electrode of the battery (e.g., graphite) can undergo a stabilization process of increasing the reaction area by shrinking and expanding during the initial charge / discharge process. During the stabilization process, since the reaction area of the negative electrode increases, the overvoltage of the negative electrode can be reduced compared to the initial stage. That is, the increase in the reaction area of the negative electrode during the initial charge / discharge process is due to the shrinkage and expansion of the negative electrode, which causes the overvoltage to decrease.

[0008] Conversely, the overvoltage of the negative electrode can gradually increase as the battery deteriorates. For example, the overvoltage of the negative electrode can gradually increase due to the generation of the solid electrolyte interface (SEI) according to battery deterioration and the influence of the reduction decomposition of the electrolyte.

[0009] Therefore, in order to prevent the battery from deteriorating rapidly and extend the battery life, it is necessary to develop a technology that can more specifically diagnose the state of the negative electrode of the battery based on the differences caused by the deterioration and stabilization processes of the battery. Summary of the Invention

[0010] Technical Problem

[0011] The present disclosure is designed to solve the problems of the related art, and thus the present disclosure relates to providing a battery diagnostic device and method capable of more specifically diagnosing the state of the negative electrode of a battery based on the voltage and capacity of the battery.

[0012] These and other objects and advantages of the present disclosure can be understood from the following detailed description and will become more fully apparent from the exemplary embodiments of the present disclosure. In addition, it will be readily understood that the objects and advantages of the present disclosure can be achieved by the means shown in the appended claims and their combinations.

[0013] Technical Solution

[0014] A battery diagnostic device according to an aspect of the present disclosure may include: a curve generation unit configured to generate a differential curve representing the correspondence between the voltage of a battery and the differential capacity of the voltage of the battery; and a control unit configured to receive the differential curve from the curve generation unit, determine a target peak in the differential curve, determine the behavior pattern of the target peak based on a reference peak included in a preset reference curve, and diagnose the state of the negative electrode of the battery by comparing the behavior pattern determined for the target peak with a plurality of preset behavior types.

[0015] The control unit may be configured to diagnose the state of the negative electrode of the battery as an overvoltage state or a stable state according to the behavior type corresponding to the behavior pattern among the plurality of behavior types.

[0016] The plurality of behavior types may include: a first behavior type in which the voltage of the target peak exceeds the voltage of the reference peak and the differential capacity of the target peak is less than the differential capacity of the reference peak; and a second behavior type in which the voltage of the target peak is less than the voltage of the reference peak and the differential capacity of the target peak is equal to or greater than the differential capacity of the reference peak.

[0017] The control unit may be configured to diagnose the state of the negative electrode of the battery as the overvoltage state when the behavior pattern determined for the target peak corresponds to the first behavior type.

[0018] The control unit may be configured to diagnose the state of the negative electrode of the battery as the stable state when the behavior pattern determined for the target peak corresponds to the second behavior type.

[0019] When there are multiple peaks within a predetermined voltage region of the voltage based on the target peak, the control unit may be configured to select the multiple peaks, and when the differential capacity of each of the selected multiple peaks is less than the differential capacity of the reference peak and the voltage of each of the multiple peaks exceeds the voltage of the reference peak, the control unit may be configured to diagnose the state of the negative electrode of the battery as the overvoltage state.

[0020] The control unit may be configured to determine the multiple peaks within the predetermined voltage region when the behavior pattern determined for the target peak corresponds to the first behavior type.

[0021] The control unit may be configured to determine a first target peak and a second target peak having different voltages in the differential curve, determine a first behavior pattern of the first target peak with respect to a first reference peak included in the reference curve and a second behavior pattern of the second target peak with respect to a second reference peak included in the reference curve, and when both the first behavior pattern and the second behavior pattern correspond to the second behavior type, diagnose the state of the negative electrode of the battery as the stable state.

[0022] The control unit may be configured to determine the first target peak and the second target peak when the behavior pattern determined for the target peak corresponds to the second behavior type.

[0023] The control unit may be configured to reduce at least one of the available SOC region and the maximum allowable temperature of the battery when the state of the negative electrode of the battery is diagnosed as the stable state.

[0024] The control unit may be configured to determine the peak having the maximum differential capacity in the differential curve as the target peak.

[0025] A battery pack according to another aspect of the present disclosure may include the battery diagnostic device according to one aspect of the present disclosure.

[0026] A battery diagnosis method according to another aspect of the present disclosure includes the following steps: a differential curve generation step that generates a differential curve representing the correspondence between the voltage of the battery and the differential capacity of the battery; a target peak determination step that determines a target peak in the differential curve; a behavior pattern determination step that determines the behavior pattern of the target peak based on a reference peak included in a preset reference curve; and a negative electrode state diagnosis step that diagnoses the state of the negative electrode of the battery by comparing the behavior pattern determined for the target peak with a plurality of preset behavior types.

[0027] Advantageous Effects

[0028] According to one aspect of the present disclosure, there is an advantage of diagnosing the state of the negative electrode of the battery as an overvoltage state or a stable state based on the voltage and capacity of the battery.

[0029] In addition, according to one aspect of the present disclosure, since the usage conditions corresponding to the battery can be set according to the diagnosed state of the negative electrode of the battery, there are advantages of being able to prevent battery deterioration and extend the lifespan.

[0030] The effects of the present disclosure are not limited to the above-mentioned effects, and those skilled in the art can clearly understand other effects not mentioned through the description of the claims. Brief Description of the Drawings

[0031] The drawings illustrate preferred embodiments of the present disclosure and are used together with the above disclosure to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure is not to be construed as limited to the drawings.

[0032] Figure 1 is a diagram schematically showing a battery diagnosis device according to an embodiment of the present disclosure.

[0033] Figure 2 is a diagram schematically showing an embodiment in which a battery diagnosis device diagnoses the state of the negative electrode of the battery based on a reference curve and a differential curve according to an embodiment of the present disclosure.

[0034] Figure 3 is a diagram schematically showing another embodiment in which a battery diagnosis device diagnoses the state of the negative electrode of the battery based on a reference curve and a differential curve according to an embodiment of the present disclosure.

[0035] Figure 4 is a diagram schematically showing still another embodiment in which a battery diagnosis device diagnoses the state of the negative electrode of the battery based on a reference curve and a differential curve according to an embodiment of the present disclosure.

[0036] Figure 5 FIG. Figure 5 is a diagram schematically showing still another embodiment of diagnosing the state of a negative electrode of a battery by a battery diagnosis device based on a reference curve and a differential curve according to an embodiment of the present disclosure.

[0037] Figure 6 FIG. is a diagram schematically showing an exemplary configuration of a battery pack including a battery diagnosis device according to an embodiment of the present disclosure.

[0038] Figure 7 FIG.

[0037] is a diagram schematically showing a battery diagnosis method according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0039] It should be understood that the terms used in the specification and the appended claims should not be construed as being limited to the general meanings and dictionary meanings, but should be interpreted based on the meanings and concepts corresponding to the technical aspects of the present disclosure on the basis of the principle that allows the inventor to define terms suitable for best explaining.

[0040] Therefore, the descriptions presented herein are merely preferred examples for illustrative purposes only and are not intended to limit the scope of the present disclosure. Thus, it should be understood that other equivalent forms and modifications can be obtained without departing from the scope of the present disclosure.

[0041] In addition, when describing the present disclosure, when it is considered that the detailed description of related known elements or functions obscures the key subject matter of the present disclosure, the detailed description is omitted herein.

[0042] Terms including ordinal numbers such as “first,” “second,” etc. may be used to distinguish one element from another among various elements, but are not intended to limit these elements by the terms.

[0043] Throughout the specification, when a part is referred to as “including” or “comprising” any element, this means that the part may also include other elements without excluding other elements, unless otherwise specifically stated.

[0044] In addition, terms such as a control unit described in the specification mean a unit that processes at least one function or operation, and may be implemented as hardware, software, or a combination of hardware and software.

[0045] In addition, throughout the specification, when a part is referred to as “connected” to another part, it is not limited to the case where they are “directly connected,” but also includes the case where they are “indirectly connected” and another element is interposed between them.

[0046] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0047] Figure 1FIG. is a diagram schematically showing a battery diagnostic device 100 according to an embodiment of the present disclosure.

[0048] Referring Figure 1 , the battery diagnostic device 100 may include a curve generation unit 110 and a control unit 120.

[0049] The curve generation unit 110 may be configured to generate a differential curve representing the correspondence between the voltage of the battery and the differential capacity of the voltage of the battery.

[0050] Here, the battery means a physically separable single independent battery cell having a negative terminal and a positive terminal. For example, a pouch-type lithium polymer battery cell may be regarded as a battery.

[0051] Specifically, the curve generation unit 110 may obtain a voltage curve representing the correspondence between the voltage of the battery and the capacity. In addition, the curve generation unit 110 may calculate the differential capacity (dQ / dV) by differentiating the capacity with respect to the voltage of the battery. The curve generation unit 110 may generate a differential curve representing the correspondence between the voltage of the battery and the calculated differential capacity.

[0052] Figure 2 FIG. is a diagram schematically showing an embodiment in which the battery diagnostic device 100 diagnoses the state of the negative electrode of the battery based on the reference curve Pa and the differential curve PDa according to an embodiment of the present disclosure.

[0053] Referring Figure 2 , when the voltage of the battery is set to X and the differential capacity with respect to the voltage of the battery is set to Y, the differential curve PDa generated by the curve generation unit 110 may be represented as an X-Y curve graph. Here, the differential capacity is a value obtained by differentiating the battery capacity with respect to the voltage and may be represented as [dQ / dV].

[0054] The control unit 120 may be configured to receive the differential curve PDa from the curve generation unit 110.

[0055] Specifically, the control unit 120 and the curve generation unit 110 may be connected to communicate with each other. The curve generation unit 110 may send the generated differential curve PDa to the control unit 120, and the control unit 120 may receive the differential curve PDa.

[0056] The control unit 120 may be configured to determine a target peak TPa in the differential curve PDa.

[0057] Here, the peak can be a point in the differential curve PDa with an upward convex form. Specifically, the peak can be a point in the differential curve PDa where the instantaneous change rate of the differential capacity with respect to the voltage is 0. Among them, the instantaneous change rate based on the low-voltage side of the peak can be positive, and the instantaneous change rate of the high-voltage side can be negative.

[0058] For example, in Figure 2 In the embodiment of, the differential curve PDa may include multiple peaks. The control unit 120 may determine any one of the multiple peaks included in the differential curve PDa as the target peak TPa. Preferably, the control unit 120 may be configured to determine the peak with the maximum differential capacity in the differential curve PDa as the target peak TPa.

[0059] In Figure 2 In the embodiment of, the target peak TPa with the maximum differential capacity in the differential curve PDa may have a voltage V2, and the differential capacity may be a2.

[0060] In addition, the control unit 120 may be configured to determine the behavior mode of the target peak TPa based on the reference peak RPa included in the preset reference curve Pa.

[0061] Specifically, the control unit 120 may determine the behavior mode of the target peak TPa by comparing the voltage of the reference peak RPa with the voltage of the target peak TPa and comparing the differential capacity of the reference peak RPa with the differential capacity of the target peak TPa.

[0062] For example, the control unit 120 may determine whether the voltage of the target peak TPa is less than or greater than the voltage of the reference peak RPa. In addition, the control unit 120 may determine whether the differential capacity of the target peak TPa is less than or greater than the differential capacity of the reference peak RPa.

[0063] In Figure 2 In the embodiment of, the voltage of the reference peak RPa may be V1, and the differential capacity may be a1. In addition, the voltage of the target peak TPa may be V2, and the differential capacity may be a2. The control unit 120 may determine that the voltage of the target peak TPa exceeds the voltage of the reference peak RPa, and the differential capacity of the target peak TPa is less than the differential capacity of the reference peak RPa.

[0064] The control unit 120 may be configured to diagnose the state of the negative electrode of the battery by comparing the behavior mode determined for the target peak with multiple predetermined behavior types.

[0065] Specifically, the control unit 120 may be configured to diagnose the state of the negative electrode of the battery as an overvoltage state or a stable state according to the behavior type corresponding to the behavior mode among the multiple behavior types.

[0066] For example, the multiple behavior types may include a first behavior type corresponding to an overvoltage state and a second behavior type corresponding to a stable state.

[0067] Here, the overvoltage state may be a state in which battery degradation causes overvoltage to occur at the negative electrode of the battery compared to the negative electrode of the battery in the BOL (beginning of life) state. The stable state may be a state in which the negative electrode of the battery contracts and expands during an initial charge / discharge process.

[0068] The control unit 120 may determine a behavior pattern of the target peak TPa with respect to the reference peak RPa, and specifically diagnose whether the state of the negative electrode of the battery is an overvoltage state or a stable state based on the determined behavior pattern.

[0069] Therefore, the battery diagnostic device 100 according to an embodiment of the present disclosure has the advantage of specifically classifying and diagnosing the state of the negative electrode of the battery based on the differential curve of the battery.

[0070] In addition, the control unit 120 provided for the battery diagnostic device 100 may optionally include a processor, an application specific integrated circuit (ASIC), another chipset, logic circuits, registers, a communication modem, and data processing devices, etc. known in the art for performing various control logics executed in the present disclosure. Additionally, when the control logic is implemented in software, the control unit 120 may be implemented as a collection of program modules. At this time, 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 in various well-known ways.

[0071] In addition, the battery diagnostic device 100 may further include a storage unit 130. The storage unit 130 may store data or programs necessary for the operation and function of each component of the battery diagnostic device 100, data generated during the execution of the operation or function, etc. The type of the storage unit 130 is not particularly limited as long as it is a known information storage device capable of recording, erasing, updating, and reading data. As an example, the information storage device may include a RAM, a flash memory, a ROM, an EEPROM, a register, etc. Additionally, the storage unit 130 may store program codes in which the processes executable by the control unit 120 are defined.

[0072] For example, the storage unit 130 may store a reference curve and a voltage curve of the battery. The curve generation unit 110 may access the storage unit 130 to obtain the voltage curve, and then generate a differential curve based on the obtained voltage curve. As another example, the curve generation unit 110 may directly receive the voltage curve from the outside.

[0073] In addition, the storage unit 130 can store the differential curve generated by the curve generation unit 110. Additionally, the control unit 120 can directly receive the differential curve from the curve generation unit 110 or can access the storage unit 130 to obtain the differential curve stored in the storage unit 130. Additionally, the control unit 120 can access the storage unit 130 to obtain the reference curve of the battery.

[0074] In the following, various behavior types and the process of diagnosing the state of the negative electrode of the battery according to the behavior types will be described in detail.

[0075] The various behavior types can include a first behavior type in which the voltage of the target peak exceeds the voltage of the reference peak and the differential capacity of the target peak is less than the differential capacity of the reference peak.

[0076] The control unit 120 can be configured to diagnose the state of the negative electrode of the battery as an overvoltage state when the behavior pattern determined for the target peak corresponds to the first behavior type.

[0077] For example, in Figure 2 the embodiment, the voltage of the target peak TPa can be V2, and the voltage of the reference peak RPa can be V1. Additionally, the differential capacity of the target peak TPa can be a2, and the differential capacity of the reference peak RPa can be a1. Since the voltage of the target peak TPa exceeds the voltage of the reference peak RPa and the differential capacity of the target peak TPa is less than the differential capacity of the reference peak RPa, the control unit 120 can determine that the behavior pattern of the target peak TPa corresponds to the first behavior type. Therefore, the control unit 120 can Figure 2 diagnose the state of the negative electrode of the battery as an overvoltage state.

[0078] In addition, the various behavior types can include a second behavior type in which the voltage of the target peak TPb is less than the voltage of the reference peak RPb and the differential capacity of the target peak TPb is equal to or greater than the differential capacity of the reference peak RPb.

[0079] The control unit 120 can be configured to diagnose the state of the negative electrode of the battery as a stable state when the behavior pattern determined for the target peak corresponds to the second behavior type.

[0080] Figure 3 FIG. is a schematic diagram showing another embodiment of diagnosing the state of the negative electrode of the battery by the battery diagnosis device 100 based on the reference curve Pb and the differential curve PDb according to an embodiment of the present disclosure.

[0081] Figure 3 The reference curve Pb and the differential curve PDb of Figure 2 can be different from Figure 2and Figure 3 The target battery may be a different battery.

[0082] A reference curve may be set for each battery, and preferably, the reference curve may be preset by reflecting the BOL state of the battery. That is, for batteries of the same type, the reference curve is not set uniformly, but can be independently set for each battery by reflecting the BOL state of the battery. Therefore, the BOL state of the battery considered as the target for diagnosing the state of the negative electrode can be used to determine the state of the negative electrode of the battery diagnosed by the control unit 120.

[0083] In Figure 3 the embodiment, the voltage of the target peak TPb may be Vb, and the voltage of the reference peak RPb may be Va. Additionally, the differential capacity of the target peak TPb may be b2, and the differential capacity of the reference peak RPb may be b1. Since the voltage of the target peak TPb is less than the voltage of the reference peak RPb and the differential capacity of the target peak TPb is equal to or greater than the differential capacity of the reference peak RPb, the control unit 120 may determine that the behavior pattern of the target peak TPb corresponds to the second behavior type. Therefore, the control unit 120 may Figure 3 judge the state of the negative electrode of the battery as a stable state.

[0084] When there are multiple peaks within a predetermined voltage region based on the voltage of the target peak, the control unit 120 may be configured to select the multiple peaks.

[0085] Figure 4 is a diagram schematically showing still another embodiment of diagnosing the state of the negative electrode of a battery by the battery diagnosis device 100 based on a reference curve and a differential curve according to an embodiment of the present disclosure. Hereinafter, it is assumed that Figure 2 and Figure 4 the reference curve and the differential curve are the same.

[0086] In Figure 4 the embodiment, the first peak TPa1 and the second peak TPa2 may be included in a predetermined voltage region of the differential curve PDa based on the voltage of the target peak TPa. Here, the first peak TPa1 may be the target peak TPa.

[0087] For example, the predetermined voltage region may be a 0.2V region based on the voltage of the target peak TPa. The control unit 120 may select the first peak TPa1 and the second peak TPa2 within a voltage region of 0.2V based on V2, which is the voltage of the target peak TPa. Preferably, the control unit 120 may select the peak having the differential capacity closest to the first peak TPa1 within the predetermined voltage region as the second peak TPa2.

[0088] When the differential capacity of each of the selected multiple peaks is less than the differential capacity of the reference peak RPa and the voltage of each of the multiple peaks exceeds the voltage of the reference peak RPa, the control unit 120 may be configured to diagnose the state of the negative electrode of the battery as an overvoltage state.

[0089] For example, in Figure 4 the embodiment, the voltage of the first peak TPa1 may be V2, the voltage of the second peak TPa2 may be V3, and the voltage of the reference peak RPa may be V1. Additionally, the differential capacity of the first peak TPa1 may be a2, the differential capacity of the second peak TPa2 may be a3, and the differential capacity of the reference peak RPa may be a1. Since the voltages of the first peak TPa1 and the second peak TPa2 exceed the voltage of the reference peak RPa and the differential capacities of the first peak TPa1 and the second peak TPa2 are less than the differential capacity of the reference peak RPa, the control unit 120 may be configured to Figure 4 the state of the negative electrode of the battery as an overvoltage state.

[0090] Furthermore, the control unit 120 may be configured to determine multiple peaks within a predetermined voltage region when the behavior pattern determined for the target peak TPa corresponds to the first behavior type.

[0091] For example, referring to Figure 2 and Figure 4 , the voltage of the target peak TPa may exceed the voltage of the reference peak RPa, and the differential capacity of the target peak TPa may be less than the differential capacity of the reference peak RPa. Thus, the control unit 120 may first determine the behavior pattern of the target peak TPa, and then determine the first peak TPa1 and the second peak TPa2 when the behavior pattern determined for the target peak TPa corresponds to the first behavior type.

[0092] That is, when the behavior pattern of the target peak TPa is the first behavior type, the control unit 120 may additionally compare the behavior patterns of the first peak TPa1 and the second peak TPa2 with multiple behavior types in order to more accurately diagnose the state of the negative electrode of the battery.

[0093] Therefore, the control unit 120 can more specifically and accurately diagnose the state of the negative electrode of the battery by further considering the behavior pattern of the second peak TPa2 as well as the behavior pattern of the first peak TPa1.

[0094] The control unit 120 may be configured to determine a first target peak and a second target peak having different voltages in the differential curve.

[0095] Specifically, the voltage bands in which the first target peak and the second target peak appear may be different from each other. For example, the first target peak may appear around about 3.7V, and the second target peak may appear around about 3.6V. Here, the first target peak may be the target peak.

[0096] Figure 5 FIG. is a diagram schematically showing still another embodiment in which the battery diagnosis device 100 diagnoses the state of the negative electrode of the battery based on the reference curve and the differential curve according to an embodiment of the present disclosure.

[0097] For example, in Figure 5 the embodiment, the voltage of the first target peak TPb1 may be Vb, and the differential capacity may be b2. The voltage of the second target peak TPb2 may be Vd, and the differential capacity may be b4.

[0098] Preferably, the control unit 120 may determine the target peak TPb as the first target peak TPb1. In addition, the control unit 120 may determine, in a voltage region having a voltage less than the target peak TPb, a peak having the maximum differential capacity as the second target peak TPb2.

[0099] The control unit 120 may be configured to determine a first behavior pattern of the first target peak TPb1 with respect to the first reference peak RPb1 included in the reference curve PDb and a second behavior pattern of the second target peak TPb2 with respect to the second reference peak RPb2 included in the reference curve PDb.

[0100] For example, in Figure 5 the embodiment, the voltage of the first target peak TPb1 may be Vb, the voltage of the first reference peak RPb1 may be Va, the voltage of the second target peak TPb2 may be Vd, and the voltage of the second reference peak RPb2 may be Vc. In addition, the differential capacity of the first target peak TPb1 may be b2, the differential capacity of the first reference peak RPb1 may be b1, the differential capacity of the second target peak TPb2 may be b4, and the differential capacity of the second reference peak RPb2 may be b3.

[0101] In addition, the voltage of the first target peak TPb1 may be less than the voltage of the first reference peak RPb1, and the differential capacity of the first target peak TPb1 may be greater than the differential capacity of the first reference peak RPb1. In addition, the voltage of the second target peak TPb2 may be less than the voltage of the second reference peak RPb2, and the differential capacity of the second target peak TPb2 may be greater than the differential capacity of the second reference peak RPb2.

[0102] The control unit 120 may be configured to diagnose the state of the negative electrode of the battery as a stable state when both the first behavior pattern and the second behavior pattern correspond to the second behavior type.

[0103] For example, in Figure 5 the embodiment of, both the first behavior pattern of the first target peak TPb1 and the second behavior pattern of the second target peak TPb2 may correspond to the second behavior type. Therefore, the control unit 120 may Figure 5 diagnose the state of the negative electrode of the battery as a stable state.

[0104] The control unit 120 may be configured to determine the first target peak TPb1 and the second target peak TPb2 when the behavior pattern determined for the target peak TPb corresponds to the second behavior type.

[0105] For example, referring to Figure 3 and Figure 5 , the voltage of the target peak TPb may be less than the voltage of the reference peak RPb, and the differential capacity of the target peak TPb may be greater than or equal to the differential capacity of the reference peak RPb. Therefore, the control unit 120 may first determine the behavior pattern of the target peak TPb, and then determine the first target peak TPb1 and the second target peak TPb2 when the behavior pattern determined for the target peak TPb corresponds to the second behavior type.

[0106] That is, when the behavior pattern of the target peak TPb corresponds to the second behavior type, the control unit 120 may additionally compare the behavior patterns of the first target peak TPb1 and the second target peak TPb2 with multiple behavior types in order to more accurately diagnose the state of the negative electrode of the battery.

[0107] Therefore, by determining whether the behavior pattern of the target peak TPb corresponds to the second behavior type and then determining whether the behavior pattern of the second target peak TPb2 corresponds to the second behavior type, the control unit 120 can more specifically and accurately diagnose the state of the negative electrode of the battery.

[0108] The control unit 120 may be configured to reduce at least one of the available SOC region and the maximum allowable temperature of the battery when the state of the negative electrode of the battery is diagnosed as a stable state.

[0109] For example, when the state of the negative electrode of the battery is diagnosed as a stable state, the reaction area of the negative electrode may increase compared to the initial state. Since the stable state is a state in which the negative electrode contracts and expands during the initial charge and discharge process, it is less likely that lithium plating, in which lithium precipitates on the negative electrode, occurs. Therefore, in the stable state, charge / discharge C rate control for reducing the occurrence of lithium plating may not be required.

[0110] However, even if the state of the negative electrode is diagnosed as a stable state, the positive electrode of the battery may deteriorate, and a loss of the positive electrode capacity may occur due to such deterioration of the positive electrode. In order to prevent such a loss of the positive electrode capacity in advance, that is, to slow down the deterioration of the positive electrode, when the state of the negative electrode is diagnosed as a stable state, the control unit 120 may reduce at least one of the available SOC region of the battery and the maximum allowable temperature.

[0111] That is, the battery diagnosis device 100 according to an embodiment of the present disclosure may set the optimal usage conditions of the battery according to the diagnosis state of the negative electrode. Therefore, since the battery can operate according to the usage conditions set by the battery diagnosis device 100, the life of the battery can be extended.

[0112] For example, the usage conditions set by the battery diagnosis device 100 may be stored in a server or stored in a battery management system (BMS) provided for a battery pack including the corresponding battery. In addition, since the battery operates according to the set usage conditions, the life of the battery can be extended.

[0113] The battery diagnosis device 100 according to the present disclosure may be applied to a BMS (battery management system). That is, the BMS according to the present disclosure may include the above-described battery diagnosis device 100. In this configuration, at least some components of the battery diagnosis device 100 may be implemented by supplementing or adding functions of the configurations included in a conventional BMS. For example, the curve generation unit 110, the control unit 120, and the storage unit 130 of the battery diagnosis device 100 may be implemented as components of the BMS.

[0114] Figure 6 FIG. is a diagram schematically showing an exemplary configuration of a battery pack 1 including a battery diagnosis device 100 according to an embodiment of the present disclosure.

[0115] In addition, the battery diagnosis device 100 according to the present disclosure may be provided for the battery pack 1. That is, the battery pack 1 according to the present disclosure may include the above-described battery diagnosis device 100, a measurement unit 200, a charge and discharge unit 300, and at least one battery cell B. In addition, the battery pack may further include electrical devices (relays, fuses, etc.) and a housing.

[0116] The measurement unit 200 may be connected to a first sensing line SL1, a second sensing line SL2, and a third sensing line SL3.

[0117] Specifically, the first sensing line SL1 can be connected to the positive electrode of the battery cell B and the measuring unit 200. Additionally, the second sensing line SL2 can be connected to the negative electrode of the battery cell B and the measuring unit 200. The measuring unit 200 can measure the voltage of the battery cell B by calculating the difference between the voltage of the positive electrode of the battery cell B measured through the first sensing line SL1 and the voltage of the negative electrode of the battery cell B measured through the second sensing line SL2.

[0118] Additionally, the measuring unit 200 can measure the charging current and / or discharging current of the battery cell B through the current measuring unit A connected to the third sensing line SL3. For example, the current measuring unit A can be a shunt resistor or an ammeter.

[0119] The charge-discharge unit 300 can be configured to charge and / or discharge the battery cell B. During the process of charging and / or discharging the battery cell B by the charge-discharge unit 300, the measuring unit 200 can measure the voltage and current of the battery cell B.

[0120] The voltage and current of the battery cell B measured by the measuring unit 200 can be transmitted to the battery diagnostic device 100. Specifically, the curve generation unit can receive the voltage and current of the battery cell B from the measuring unit 200. The curve generation unit can generate a differential curve representing the correspondence between the voltage of the battery cell B and the differential capacity based on the received voltage and current of the battery cell B. Here, it should be noted that the prior art can be applied to the process of the curve generation unit calculating the capacity and differential capacity of the battery cell B based on the voltage and current of the battery cell B, and thus, its detailed description will be omitted.

[0121] Figure 7 FIG. is a diagram schematically showing a battery diagnostic method according to another embodiment of the present disclosure.

[0122] Preferably, each step of the battery diagnostic method according to another embodiment of the present disclosure can be executed by the battery diagnostic device 100 according to the embodiment of the present disclosure. Hereinafter, the content repeated with the previously described content will be omitted or briefly described.

[0123] Referring to Figure 7 , the battery diagnostic method can include a differential curve generation step (S100), a target peak determination step (S200), a behavior pattern determination step (S300), and a negative electrode state diagnosis step (S400).

[0124] The differential curve generation step (S100) is a step of generating a differential curve representing the correspondence between the battery voltage and the differential capacity of the battery voltage, and can be executed by the curve generation unit 110.

[0125] For example, in Figure 2In the implementation on time, the curve generation unit 110 can generate a differential curve PDa representing the correspondence between the voltage of the battery and the differential capacity.

[0126] The target peak determination step (S200) is a step of determining the target peak in the differential curve and can be executed by the control unit 120.

[0127] For example, in Figure 2 the implementation manner, the control unit 120 can determine the peak with the maximum differential capacity in the differential curve PDa as the target peak TPa. The voltage corresponding to the target peak TPa can be V2, and the corresponding differential capacity can be a2.

[0128] The behavior mode determination step (S300) is a step of determining the behavior mode of the target peak based on the reference peak included in the preset reference curve and can be executed by the control unit 120.

[0129] For example, in Figure 2 the implementation manner, the control unit 120 can determine the behavior mode of the target peak TPa such that the voltage V2 exceeds the voltage V1 of the reference peak RPa and the differential capacity a2 is less than the differential capacity a1 of the reference peak RPa.

[0130] The negative electrode state diagnosis step (S400) is a step of diagnosing the state of the negative electrode of the battery by comparing the behavior mode determined for the target peak with a plurality of preset behavior types and can be executed by the control unit 120.

[0131] Specifically, the control unit 120 can diagnose the state of the negative electrode of the battery as an overvoltage state or a stable state according to the behavior type corresponding to the behavior mode among the plurality of behavior types.

[0132] For example, according to the voltage and differential capacity of the target peak and the reference peak, the plurality of behavior types can include a first behavior type and a second behavior type. The first behavior type can be the behavior type in which the voltage of the target peak exceeds the voltage of the reference peak and the differential capacity of the target peak is less than the differential capacity of the reference peak. The second behavior type can be the behavior type in which the voltage of the target peak is less than the voltage of the reference peak and the differential capacity of the target peak is equal to or greater than the differential capacity of the reference peak.

[0133] In Figure 2 the implementation manner, the control unit 120 can determine that the behavior mode of the target peak TPa corresponds to the first behavior type. In addition, since the behavior mode of the target peak TPa corresponds to the first behavior type, the control unit 120 can Figure 2 diagnose the state of the negative electrode of the battery as an overvoltage state.

[0134] As another example, in Figure 3 In the embodiment of, the voltage Vb of the target peak TPb may be less than the voltage Va of the reference peak RPb, and the differential capacity b2 of the target peak TPb may be greater than or equal to the differential capacity b1 of the reference peak RPb. Therefore, the control unit 120 may determine that the behavior pattern of the target peak TPb corresponds to the second behavior type. In addition, the control unit 120 may Figure 3 diagnose the state of the negative electrode of the battery of as a stable state.

[0135] The battery diagnosis method has the advantage of diagnosing the state of the negative electrode of a battery specifically classified as an overvoltage state or a stable state according to the behavior pattern of the target peak.

[0136] The above-described embodiments of the present disclosure can be implemented not only by devices and methods but also by a program that implements functions corresponding to the configurations of the embodiments of the present disclosure or a recording medium on which the program is recorded. Based on the above description of the embodiments, those skilled in the art can easily implement the program or the recording medium.

[0137] The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, although indicating preferred embodiments of the present disclosure, are given by way of illustration only, since various changes and modifications within the scope of the present disclosure will be apparent to those skilled in the art from this detailed description.

[0138] In addition, those skilled in the art can make many substitutions, modifications, and changes to the present disclosure described above without departing from the technical aspects of the present disclosure, and the present disclosure is not limited to the above embodiments and drawings, but can selectively combine some or all of the embodiments to allow for various modifications.

[0139] (Reference signs)

[0140] 1: Battery pack

[0141] 100: Battery diagnosis device

[0142] 110: Curve generation unit

[0143] 120: Control unit

[0144] 130: Storage unit

[0145] 200: Measurement unit

[0146] 300: Charge and discharge unit

Claims

1. A battery diagnosis device, the battery diagnosis device comprising: a curve generation unit configured to generate a differential curve representing a correspondence between a voltage of a battery and a differential capacity of the voltage of the battery; and a control unit configured to receive the differential curve from the curve generation unit, determine a target peak in the differential curve, determine a behavior pattern of the target peak based on a reference peak included in a preset reference curve, and diagnose a state of a negative electrode of the battery by comparing the behavior pattern determined for the target peak with a plurality of preset behavior types, wherein the control unit determines the behavior pattern of the target peak by comparing a voltage of the reference peak with a voltage of the target peak and comparing a differential capacity of the reference peak with a differential capacity of the target peak.

2. The battery diagnosis device according to claim 1, Among them, wherein the control unit is configured to diagnose the state of the negative electrode of the battery as an overvoltage state or a stable state according to a behavior type corresponding to the behavior pattern among the plurality of behavior types.

3. The battery diagnosis device according to claim 2, Among them, wherein the plurality of behavior types include: a first behavior type in which a voltage of the target peak exceeds a voltage of the reference peak and a differential capacity of the target peak is less than a differential capacity of the reference peak; and a second behavior type in which a voltage of the target peak is less than a voltage of the reference peak and a differential capacity of the target peak is equal to or greater than a differential capacity of the reference peak.

4. The battery diagnosis device according to claim 3, Among them, wherein the control unit is configured to: when the behavior pattern determined for the target peak corresponds to the first behavior type, diagnose the state of the negative electrode of the battery as the overvoltage state, and wherein the control unit is configured to: when the behavior pattern determined for the target peak corresponds to the second behavior type, diagnose the state of the negative electrode of the battery as the stable state.

5. The battery diagnosis device according to claim 3, Among them, when there are multiple peaks in a predetermined voltage region based on the voltage of the target peak, the control unit is configured to select the multiple peaks, and when a differential capacity of each of the selected multiple peaks is less than a differential capacity of the reference peak and a voltage of each of the multiple peaks exceeds a voltage of the reference peak, the control unit is configured to diagnose the state of the negative electrode of the battery as the overvoltage state.

6. The battery diagnosis device according to claim 5, Among them, wherein the control unit is configured to: when the behavior pattern determined for the target peak corresponds to the first behavior type, determine the multiple peaks in the predetermined voltage region.

7. The battery diagnosis device according to claim 3, Among them, The control unit is configured to: determine a first target peak and a second target peak with different voltages in the differential curve, determine a first behavior pattern of the first target peak with respect to a first reference peak included in the reference curve and a second behavior pattern of the second target peak with respect to a second reference peak included in the reference curve, and diagnose the state of the negative electrode of the battery as the stable state when both the first behavior pattern and the second behavior pattern correspond to the second behavior type.

8. The battery diagnosis device according to claim 7, Among them, The control unit is configured to: determine the first target peak and the second target peak when the behavior pattern determined for the target peak corresponds to the second behavior type.

9. The battery diagnosis device according to claim 2, Among them, The control unit is configured to: reduce at least one of the maximum allowable temperature and the available SOC region of the battery when the state of the negative electrode of the battery is diagnosed as the stable state.

10. The battery diagnosis device according to claim 1, Among them, The control unit is configured to determine the peak with the maximum differential capacity in the differential curve as the target peak.

11. The battery diagnosis device according to claim 1, wherein, The battery diagnosis device sets the optimal usage conditions of the battery according to the diagnosis state of the negative electrode.

12. A battery pack, the battery pack includes the battery diagnosis device according to any one of claims 1 to 11.

13. A battery diagnosis method, the battery diagnosis method includes the following steps: A differential curve generation step, the differential curve generation step generates a differential curve, the differential curve represents the correspondence between the voltage of the battery and the differential capacity of the voltage of the battery; A target peak determination step, the target peak determination step determines the target peak in the differential curve; A behavior pattern determination step, the behavior pattern determination step determines the behavior pattern of the target peak based on the reference peaks included in a preset reference curve; And A negative electrode state diagnosis step, the negative electrode state diagnosis step diagnoses the state of the negative electrode of the battery by comparing the behavior pattern determined for the target peak with a plurality of preset behavior types, wherein, the behavior pattern determination step is a step of determining the behavior pattern of the target peak by comparing the voltage of the reference peak with the voltage of the target peak and comparing the differential capacity of the reference peak with the differential capacity of the target peak.

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