Battery diagnostic device and method

Abstract

A battery diagnostic device according to an embodiment of the present invention includes: a recording unit configured to record bank information regarding the voltage and capacity of each of a plurality of battery banks included in a battery module; and a control unit configured to generate a differential profile for each of the plurality of battery banks based on the bank information, determine a target peak from each of the generated differential profiles, and diagnose a state of the corresponding battery bank based on the determined target peak.

Description

[Technical Field]

[0001] This application claims priority based on Korean Patent Application No. 10-2023-0009769 filed on January 25, 2023, and Korean Patent Application No. 10-2023-0009770 filed on January 25, 2023, the entire contents of which are incorporated herein by reference in their entirety in their specifications and drawings.

[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 bank and / or a battery module. [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 is being 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] While research into these batteries is focused on increasing capacity and density, improving battery life and safety is also important. To improve battery safety, a technology is needed to accurately diagnose the battery's current state. It is necessary to prevent plating, particularly lithium deposition on the surface of the negative electrode (lithium plating). Lithium deposition on the surface of the negative electrode can cause side reactions with the electrolyte and alter the battery's kinetic balance, resulting in battery degradation. Furthermore, lithium metal deposition on the surface of the negative electrode can cause an internal short circuit in the battery, posing a risk of fire and explosion. Therefore, there is a need for a technology that can prevent lithium metal deposition by diagnosing the battery's state. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made to solve the above problems, and an object of the present invention is to provide a battery diagnostic device and method for diagnosing the state of a battery bank and / or a battery module.

[0007] Other objects and advantages of the present invention can be understood from the following description and become more apparent from the embodiments of the present invention, and can be realized by the means and combinations thereof as 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 recording unit configured to record bank information regarding the voltage and capacity of each of a plurality of battery banks included in a battery module; and a control unit configured to generate a differential profile for each of the plurality of battery banks based on the bank information, determine a target peak from each of the generated differential profiles, and diagnose a state of the corresponding battery bank based on the determined target peak.

[0009] The control unit may be configured to generate a differential profile indicating a correspondence relationship between the capacity and a differential voltage of each of the plurality of battery banks, and to determine the target peak included in a predetermined reference voltage interval from each of the generated differential profiles.

[0010] The control unit may be configured to diagnose a state of the battery bank as normal when the determined number of target peaks is equal to or less than the number of reference peaks included in the reference voltage section of a preset reference differential profile.

[0011] The control unit may be configured to diagnose a state of the battery bank in which the determined number of target peaks exceeds the number of reference peaks as an abnormal state.

[0012] The reference differential profile may be preset to indicate a correspondence between voltage and differential capacity of a reference battery bank.

[0013] The control unit may be configured to diagnose a state of a corresponding battery bank as abnormal when the determined number of target peaks exceeds the number of reference peaks and a voltage difference between the target peaks is equal to or greater than a predetermined critical voltage.

[0014] The control unit may be configured to generate a differential profile indicating a correspondence relationship between the capacity and a differential voltage of each of the plurality of battery banks based on the bank information, and to determine a target peak included in a predetermined reference capacity interval from each of the generated differential profiles.

[0015] The control unit may be configured to diagnose a state of the battery bank as normal when the number of the determined target peaks is equal to or less than the number of reference peaks included in the reference capacity section of a preset reference differential profile.

[0016] The control unit may be configured to diagnose a state of the battery bank in which the determined number of target peaks exceeds the number of reference peaks as an abnormal state.

[0017] The reference differential profile may be preset to indicate a correspondence between the capacity and the differential voltage of a reference battery bank.

[0018] The control unit may be configured to diagnose the state of the corresponding battery bank as an abnormal state when the number of the determined target peaks exceeds the number of the reference peaks and a capacity difference between the target peaks is equal to or greater than a preset threshold.

[0019] The control unit may be configured to calculate an abnormality ratio indicating a ratio of the plurality of battery banks in an abnormal state, and diagnose the state of the battery module as a normal state or an abnormal state based on the abnormality ratio.

[0020] The control unit may be configured to diagnose the state of the battery module as the normal state if the abnormal ratio is less than a preset critical ratio.

[0021] The control unit may be configured to diagnose the state of the battery module as the abnormal state if the abnormal ratio is equal to or greater than the critical ratio.

[0022] The control unit may be configured to change a charging condition preset for the battery module if the state of the battery module is diagnosed as an abnormal state.

[0023] The control unit may be configured to alleviate the fast charging conditions of the battery module by reducing a maximum charging C rate preset for the battery module if the state of the battery module is diagnosed as an abnormal state.

[0024] The control unit may be configured to select a reference capacity having a minimum corresponding differential voltage from a preset reference differential profile for a reference battery bank, select a reference voltage corresponding to the reference capacity from a preset reference bank profile for the reference battery bank, and set a voltage section equal to or lower than the reference voltage as the reference voltage section.

[0025] The reference differential profile may be preset to indicate a correspondence between the capacity and differential voltage of a reference battery bank.

[0026] The reference bank profile may be preset to indicate a correspondence between the voltage and capacity of the reference battery bank.

[0027] The control unit may be configured to select a reference capacity having a minimum corresponding differential voltage from a preset reference differential profile, and set a capacity section equal to or less than the reference capacity as the reference capacity section.

[0028] A battery pack according to another aspect of the present invention includes the battery diagnostic device according to an aspect of the present invention.

[0029] According to yet another aspect of the present invention, a battery diagnosis method includes: a recording step of recording bank information regarding the voltage and capacity of each of a plurality of battery banks included in a battery module; a differential profile generating step of generating a differential profile for each of the plurality of battery banks based on the bank information; a target peak determining step of determining a target peak from each of the generated plurality of differential profiles; and a diagnosis step of diagnosing a state of the corresponding battery bank based on the determined target peak. [Effects of the Invention]

[0030] A battery diagnostic device according to an aspect of the present invention can accurately diagnose the state of a battery bank and / or a battery module by taking into account uneven deterioration of a plurality of battery cells.

[0031] 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.

[0032] 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 the matters described in the drawings. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a diagram illustrating a battery diagnostic device according to an embodiment of the present invention; [Figure 2] 1A and 1B are schematic diagrams illustrating exemplary configurations of a battery bank and battery modules according to an embodiment of the present invention; [Figure 3] FIG. 10 is a schematic diagram illustrating a differential profile according to an embodiment of the present invention. [Figure 4] FIG. 10 is a schematic diagram illustrating a reference differential profile according to an embodiment of the present invention. [Figure 5]FIG. 2 is a schematic diagram illustrating a reference differential profile according to an embodiment of the present invention. [Figure 6] FIG. 10 is a schematic diagram illustrating a differential profile according to an embodiment of the present invention. [Figure 7] FIG. 10 is a schematic diagram illustrating a reference differential profile according to an embodiment of the present invention. [Figure 8] 10 is a diagram schematically illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention. [Figure 9] 10 is a diagram illustrating a battery diagnostic method according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] The terms and words used in this specification and claims should not be interpreted as being limited to their ordinary and dictionary meanings, but should be interpreted as having meanings and concepts that correspond to the technical ideas of the present invention, in accordance with the principle that the inventor himself can appropriately define the concepts of terms in order to best explain the invention.

[0035] 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 therefor at the time of this application.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0041] FIG. 1 is a diagram illustrating a battery diagnostic device 100 according to an embodiment of the present invention.

[0042] Referring to FIG. 1, a battery diagnostic device 100 according to an embodiment of the present invention includes a recording unit 110 and a control unit 120.

[0043] The recording unit 110 may be configured to record bank information regarding the voltage and capacity of each of a plurality of battery banks included in the battery module.

[0044] FIG. 2 is a diagram illustrating an exemplary configuration of a battery bank BB and a battery module BM according to an embodiment of the present invention.

[0045] In the embodiment of FIG. 2, multiple battery cells BC may be connected in parallel. A battery bank BB may include multiple battery cells BC connected in parallel. And, multiple battery banks BB may be connected in series. A battery module BM may include multiple battery banks BB connected in parallel. Hereinafter, the connection configuration of the battery cells BC, the battery bank BB, and the battery module BM will be described based on the embodiment of FIG. 2.

[0046] Here, the term "battery cell" 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 cell.

[0047] The recording unit 110 may record a battery bank profile indicating the correspondence between the voltage and capacity of each of the multiple battery banks. For example, if the X-axis represents capacity and the Y-axis represents voltage, the battery bank profile may be represented as an XY graph. Also, if voltage is represented as "V" and capacity is represented as "Q," the battery bank profile may be represented as a "QV profile." In other words, the recording unit 110 may record bank information, which is information indicating the correspondence between the voltage and capacity of each of the multiple battery banks.

[0048] The control unit 120 may be configured to generate a differential profile for each of the multiple battery banks based on the bank information.

[0049] Specifically, the control unit 120 can generate at least one of a differential profile DP1 that indicates the correspondence between voltage and differential capacitance and a differential profile DP2 that indicates the correspondence between capacitance and differential voltage based on the bank information recorded in the recording unit 110.

[0050] Then, the control unit 120 can diagnose the state of the battery module based on the generated differential profile.

[0051] In the following, an embodiment in which the control unit 120 generates a differential profile DP1 that indicates the correspondence between voltage and differential capacity and diagnoses the state of the battery bank based on the differential profile DP1 will be described first, followed by an embodiment in which the control unit 120 generates a differential profile DP2 and diagnoses the state of the battery bank based on the differential profile DP2.

[0052] Here, differential capacitance refers to the rate of change of capacitance with respect to voltage. For example, if voltage is represented as "V" and capacitance is represented as "Q," differential capacitance can be expressed as "dQ / dV."

[0053] The control unit 120 can generate a differential profile DP1 that indicates the correspondence between voltage and differential capacitance based on the bank information recorded in the recording unit 110. For example, if the X-axis represents voltage and the Y-axis represents differential capacitance, the differential profile DP1 can be expressed as an XY graph. Furthermore, if voltage is represented as "V" and differential capacitance is represented as "dQ / dV," the differential profile DP1 can be expressed as a "V-dQ / dV profile." Here, differential capacitance refers to the rate of change of capacitance with respect to voltage. For example, if voltage is represented as "V" and capacitance is represented as "Q," the differential capacitance can be expressed as "dQ / dV."

[0054] 3 is a diagram illustrating a differential profile DP1 according to an embodiment of the present invention. Specifically, the embodiment of FIG. 3 illustrates a differential profile DP1 for one of a plurality of battery banks included in a battery module. In the embodiment of FIG. 3, the voltage range of the battery bank may be 3.4V to 4.2V.

[0055] The control unit 120 may be configured to determine a target peak tp included in a preset reference voltage interval RV from each of the generated multiple differential profiles DP1.

[0056] Specifically, the target peak tp may refer to a peak within a predetermined reference voltage interval RV among the peaks included in the differential profiles DP1. Here, the peak may be a point where the rate of change of the differential capacitance with respect to the voltage is 0 and has an upwardly convex shape. Specifically, the slope of the differential profile DP1 may change from positive to negative based on the peak.

[0057] For example, in the embodiment of FIG. 3, assume that the reference voltage section RV is preset to 3.4 V to 3.6 V. The differential profile DP1 may include multiple peaks (a first peak p1, a second peak p2, a third peak p3, a fourth peak p4, and a fifth peak p5). Here, the voltage corresponding to the first peak p1 may be 3.45 V, and the voltage corresponding to the second peak p2 may be 3.5 V. That is, only the first peak p1 and the second peak p2 belong to the reference voltage section RV, while the third peak p3, the fourth peak p4, and the fifth peak p5 do not belong to the reference voltage section RV. Therefore, the control unit 120 may determine the first peak p1 and the second peak p2 as the target peaks tp. Preferably, the control unit 120 may determine the first peak p1 as the first target peak tp1 and the second peak p2 as the second target peak tp2.

[0058] The control unit 120 may be configured to diagnose the condition of the corresponding battery bank based on the determined target peak tp.

[0059] Specifically, the control unit 120 may be configured to diagnose the state of the battery bank as normal or abnormal depending on the determined number of target peaks tp. Preferably, the control unit 120 may compare the number of target peaks tp with the number of reference peaks rp of a preset reference differential profile RP1, and diagnose the state of the battery bank depending on the comparison result.

[0060] Here, the reference differential profile RP1 may be preset to indicate a correspondence relationship between the voltage and differential capacity of the reference battery bank. That is, the controller 120 may compare the number of target peaks tp included in the reference voltage section RV of the differential profile DP1 with the number of reference peaks rp included in the reference voltage section RV of the reference differential profile RP1.

[0061] For example, the reference battery bank may be a test bank produced to generate the reference differential profile RP1 or a battery bank in a BOL (Beginning of Life) state. Preferably, a reference battery bank is set for each of a plurality of battery banks, and the battery bank in the BOL state may be set as the reference battery bank. That is, for each battery bank, the differential profile of the battery bank in the BOL state (reference battery bank) may be set as the reference differential profile RP1 for that battery bank.

[0062] FIG. 4 is a diagram illustrating a reference differential profile RP1 according to an embodiment of the present invention.

[0063] Specifically, the embodiment of Figure 4 illustrates a reference differential profile RP1 for a reference battery bank. In the embodiment of Figure 4, the voltage range of the reference battery bank may be 3.4V to 4.2V.

[0064] Preferably, the reference battery bank according to the embodiment of Fig. 4 may correspond to the battery bank according to the embodiment of Fig. 3. For example, the reference differential profile RP1 according to the embodiment of Fig. 4 may be the differential profile DP1 for the BOL state of the battery bank according to the embodiment of Fig. 3. The reference voltage section RV of the reference differential profile RP1 may include one reference peak rp.

[0065] In one embodiment, the control unit 120 may diagnose the battery bank as being in a normal state if the number of determined target peaks tp is equal to or less than the number of reference peaks rp included in the reference voltage section RV of the preset reference differential profile RP1. Conversely, the control unit 120 may diagnose the battery bank as being in an abnormal state if the number of determined target peaks tp exceeds the number of reference peaks rp.

[0066] If the number of target peaks tp exceeds the number of reference peaks rp, it can be said that uneven deterioration has occurred in the battery cells included in the battery bank.

[0067] In the BOL state, the states of the battery cells are substantially equal. However, if the battery cells deteriorate unevenly as the battery bank operates, the number of target peaks tp may exceed the number of reference peaks rp. Conversely, if the battery cells deteriorate unevenly even when the battery bank is operated, the number of target peaks tp may be less than the number of reference peaks rp. This is because the difference in the states of the battery cells due to uneven deterioration appears as an increased number of target peaks tp in the differential profile DP1 for the battery bank. Therefore, the control unit 120 may diagnose the state of the battery bank as normal or abnormal depending on the result of comparing the determined number of target peaks tp with the preset number of reference peaks rp.

[0068] For example, in the embodiment of Fig. 3, the derivative profile DP1 may include a first target peak tp1 and a second target peak tp2. In addition, in the embodiment of Fig. 4, the reference derivative profile RP1 may include one reference peak rp. Because the number of target peaks tp exceeds the number of reference peaks rp, the control unit 120 may diagnose the battery bank as being in an abnormal state.

[0069] The battery diagnostic device 100 can accurately diagnose the state of the battery bank based on the number of target peaks tp that reflect the uneven deterioration of the plurality of battery cells.

[0070] In another embodiment, the control unit 120 may be configured to diagnose the state of the corresponding battery bank as abnormal if the number of determined target peaks tp exceeds the number of reference peaks rp and the voltage difference between the target peaks tp is equal to or greater than a predetermined critical voltage.

[0071] The controller 120 may diagnose the state of the battery bank by considering not only the number of target peaks tp but also the voltage difference between the target peaks tp. As described above, if a difference in state occurs among multiple battery cells, the number of target peaks tp may exceed the number of reference peaks rp.

[0072] If the number of target peaks tp exceeds the number of reference peaks rp, the control unit 120 may calculate a voltage difference between the target peaks tp. Then, the control unit 120 may compare the calculated voltage difference with a preset critical voltage. Here, the critical voltage may be preset to indicate that the degree of uneven deterioration among the battery cells is serious enough to determine that the state of the battery bank is abnormal. For example, the critical voltage may be preset to a value equal to or greater than 0.01 V. Preferably, the critical voltage may be preset to 0.02 V.

[0073] 3, the voltage of the first target peak tp1 may be 3.45 V and the voltage of the second target peak tp2 may be 3.5 V. The control unit 120 may calculate the voltage difference between the first target peak tp1 and the second target peak tp2 to be 0.5 V. Because the calculated voltage difference (0.5 V) is greater than or equal to the preset critical voltage (0.02 V), the control unit 120 may diagnose the battery bank as being in an abnormal state.

[0074] The battery diagnostic device 100 can more accurately diagnose the state of the battery bank based on the number of target peaks tp and the voltage difference of the target peaks tp.

[0075] Hereinafter, the reference voltage section RV in which the reference peak rp and the target peak tp are determined will be described with reference to FIGS.

[0076] The control unit 120 may be configured to select a reference capacity with a minimum corresponding differential voltage from a preset reference differential profile RP2 for the reference battery bank.

[0077] Here, the reference differential profile RP2 may be preset to indicate the correspondence between the capacity and differential voltage of a reference battery bank. The differential voltage refers to the rate of change of voltage relative to capacity. For example, if voltage is represented as "V" and capacity is represented as "Q," the differential voltage may be expressed as "dV / dQ."

[0078] FIG. 5 is a schematic diagram illustrating a reference differential profile RP2 according to one embodiment of the present invention. Specifically, in the embodiment of FIG. 5, the capacitance is normalized to a range of 0 to 1. In the embodiment of FIG. 5, if the X-axis represents capacitance and the Y-axis represents differential voltage, the reference differential profile RP2 can be represented as an XY graph. Furthermore, if the capacitance is represented as "Q" and the differential voltage is represented as "dV / dQ," the reference differential profile RP2 can be represented as a "Q-dV / dQ profile."

[0079] 5, the control unit 120 may select a point min in the reference differential profile RP2 where the differential voltage is minimum. Here, the capacitance corresponding to the point min may be 0.3. Therefore, the control unit 120 may select the reference capacitance as 0.3.

[0080] The control unit 120 may be configured to select a reference voltage corresponding to a reference capacity from a preset reference bank profile for the reference battery bank.

[0081] Here, the reference bank profile may be preset to indicate a correspondence relationship between the voltage and capacity of a reference battery bank. For example, the reference bank profile may be a profile in which the corresponding voltage and capacity of a reference battery are mapped.

[0082] The control unit 120 may select a reference voltage corresponding to the reference capacitance using the reference bank profile. For example, the reference voltage selected by the control unit 120 may be 3.6V.

[0083] The control unit 120 may be configured to set a voltage section equal to or lower than the reference voltage as the reference voltage section RV.

[0084] 3, the control unit 120 may set the reference voltage section RV to a voltage section of 3.6 V or less. Specifically, since the voltage section of the battery bank is 3.4 V to 4.2 V, the control unit 120 may set the reference voltage section RV to a voltage section of 3.4 V to 3.6 V.

[0085] To diagnose the state of the battery bank based on the unbalanced deterioration of the negative electrodes of the battery cells, the battery diagnostic device 100 may determine a peak included in the reference voltage section RV as the target peak tp. That is, the reference voltage section RV may be a voltage section that reflects the deterioration state of the negative electrodes. The deterioration state of the negative electrodes may be clearly expressed in the differential profile DP1. Therefore, the battery diagnostic device 100 may diagnose the state of the battery bank based on whether unbalanced deterioration has occurred in the negative electrodes of the plurality of battery cells included in the battery bank.

[0086] Hereinafter, an embodiment will be described in which the control unit 120 generates a differential profile DP2 that indicates the correspondence between the capacity and the differential voltage, and diagnoses the state of the battery bank based on the differential profile DP2.

[0087] Here, the differential voltage means the rate of change of voltage with respect to capacitance. For example, if voltage is represented as "V" and capacitance is represented as "Q," the differential voltage can be expressed as "dV / dQ."

[0088] The control unit 120 can generate a differential profile DP2 that indicates the correspondence between capacitance and differential voltage based on the bank information recorded in the recording unit 110. For example, if the X-axis represents capacitance and the Y-axis represents differential voltage, the differential profile DP2 can be expressed as an XY graph. Furthermore, if capacitance is represented as "Q" and differential voltage is represented as "dV / dQ," the differential profile DP2 can be expressed as a "Q-dV / dQ profile."

[0089] FIG. 6 is a diagram illustrating a differential profile DP2 according to an embodiment of the present invention.

[0090] Specifically, the embodiment of Fig. 6 is a diagram showing a differential profile DP2 for one of a plurality of battery banks included in a battery module. In the embodiment of Fig. 6, the capacity range of the battery bank may be normalized to 0 to 1. It should be noted that the normalization of capacity is for convenience of explanation and the process of normalizing capacity may be omitted.

[0091] The control unit 120 can be configured to determine a target peak tp included in a preset reference capacity interval RQ from each of the generated multiple differential profiles DP2.

[0092] Specifically, the target peak tp may refer to a peak within a predetermined reference capacitance range RQ among the peaks included in the differential profiles DP2. Here, the peak may be a point where the rate of change of the differential voltage with respect to the capacitance is zero and has an upwardly convex shape. Specifically, the slope of the differential profile DP2 may change from positive to negative with respect to the peak.

[0093] For example, in the embodiment of FIG. 6, assume that the reference capacity interval RQ is preset to 0 to 0.3. The differential profile DP2 may include multiple peaks (first peak p1, second peak p2, third peak p3, and fourth peak p4). Here, only the first peak p1 and the second peak p2 belong to the reference capacity interval RQ, and the third peak p3 and the fourth peak p4 do not belong to the reference capacity interval RQ. Therefore, the control unit 120 may determine the first peak p1 and the second peak p2 as the target peaks tp. Preferably, the control unit 120 may determine the first peak p1 as the first target peak tp1 and the second peak p2 as the second target peak tp2.

[0094] The control unit 120 may be configured to diagnose the condition of the corresponding battery bank based on the determined target peak tp.

[0095] Specifically, the control unit 120 may be configured to diagnose the state of the battery bank as normal or abnormal depending on the determined number of target peaks tp. Preferably, the control unit 120 may compare the number of target peaks tp with the number of reference peaks rp of a preset reference differential profile RP, and diagnose the state of the battery bank depending on the comparison result.

[0096] Here, the reference differential profile RP may be preset to indicate a correspondence relationship between the capacity and differential voltage of the reference battery bank. That is, the controller 120 may compare the number of target peaks tp included in the reference capacity section RQ of the differential profile DP2 with the number of reference peaks rp included in the reference capacity section RQ of the reference differential profile RP.

[0097] For example, the reference battery bank may be a test bank produced to generate the reference differential profile RP or a battery bank in a BOL state. Preferably, a reference battery bank is set for each of a plurality of battery banks, and the battery bank in a BOL state may be set as the reference battery bank. That is, for each battery bank, the differential profile DP2 of the battery bank in the BOL state (reference battery bank) may be set as the reference differential profile RP of that battery bank.

[0098] FIG. 7 is a schematic diagram illustrating a reference differential profile RP according to an embodiment of the present invention.

[0099] Specifically, the embodiment of Figure 7 illustrates a reference differential profile RP for a reference battery bank. In the embodiment of Figure 7, the capacity range of the reference battery bank may be normalized to 0 to 1. As mentioned above, the normalization of capacity is for convenience of explanation.

[0100] Preferably, the reference battery bank according to the embodiment of Fig. 7 may correspond to the battery bank according to the embodiment of Fig. 6. For example, the reference differential profile RP according to the embodiment of Fig. 7 may be the differential profile DP2 for the BOL state of the battery bank according to the embodiment of Fig. 6. The reference capacity section RQ of the reference differential profile RP may include one reference peak rp.

[0101] In one embodiment, the control unit 120 may diagnose the battery bank as being in a normal state if the number of determined target peaks tp is equal to or less than the number of reference peaks rp included in the reference capacity section RQ of the preset reference differential profile RP. Conversely, the control unit 120 may diagnose the battery bank as being in an abnormal state if the number of determined target peaks tp exceeds the number of reference peaks rp.

[0102] If the number of target peaks tp exceeds the number of reference peaks rp, it can be said that uneven deterioration of the battery cells included in the battery bank has occurred.

[0103] In the BOL state, the states of the battery cells are substantially equal. However, if the battery cells deteriorate unevenly as the battery bank operates, the number of target peaks tp may exceed the number of reference peaks rp. Conversely, if the battery cells deteriorate unevenly even when the battery bank is operated, the number of target peaks tp may be less than the number of reference peaks rp. This is because the difference in the states of the battery cells due to uneven deterioration appears as an increased number of target peaks tp in the differential profile DP2 for the battery bank. Therefore, the control unit 120 may diagnose the state of the battery bank as normal or abnormal depending on the result of comparing the determined number of target peaks tp with the preset number of reference peaks rp.

[0104] For example, in the embodiment of Fig. 6, the derivative profile DP2 may include a first target peak tp1 and a second target peak tp2. And, in the embodiment of Fig. 7, the reference derivative profile RP may include one reference peak rp. Because the number of target peaks tp exceeds the number of reference peaks rp, the control unit 120 may diagnose the state of the battery bank as abnormal.

[0105] The battery diagnostic device 100 can accurately diagnose the state of the battery bank based on the number of target peaks tp that reflect the uneven deterioration of the plurality of battery cells.

[0106] In another embodiment, the control unit 120 may be configured to diagnose the state of the corresponding battery bank as abnormal if the number of determined target peaks tp exceeds the number of reference peaks rp and the capacity difference between the target peaks tp is equal to or greater than a preset threshold.

[0107] The controller 120 may diagnose the state of the battery bank by considering not only the number of target peaks tp but also the capacity difference between the target peaks tp. As described above, if a difference in state occurs among multiple battery cells, the number of target peaks tp may exceed the number of reference peaks rp.

[0108] If the number of target peaks tp exceeds the number of reference peaks rp, the control unit 120 may calculate a capacity difference between the target peaks tp. The control unit 120 may then compare the calculated capacity difference with a preset threshold. Here, the threshold may be preset to indicate that the degree of uneven deterioration among the plurality of battery cells is serious enough to determine that the state of the battery bank is abnormal. For example, the threshold may be preset to 3%. If the capacity difference between the target peaks tp is equal to or greater than the preset threshold (3%), the control unit 120 may diagnose the state of the battery bank as abnormal. In one embodiment, the control unit 120 may calculate the capacity difference between the target peaks by using the formula "(capacity of the second target peak - capacity of the first target peak) ÷ capacity of the first target peak × 100." The control unit 120 may then compare the calculated capacity difference with the threshold.

[0109] The battery diagnostic device 100 can more accurately diagnose the state of the battery bank based on the number of target peaks tp and the capacity difference of the target peaks tp.

[0110] Hereinafter, the reference capacity section RQ in which the reference peak rp and the target peak tp are determined will be described with reference to FIGS.

[0111] The control unit 120 may be configured to select a reference capacity with a minimum corresponding differential voltage from a preset reference differential profile RP for the reference battery bank.

[0112] Here, the reference differential profile RP may be preset to indicate the correspondence between the capacity and differential voltage of a reference battery bank. The differential voltage refers to the rate of change of voltage relative to capacity. For example, if voltage is represented as "V" and capacity is represented as "Q," the differential voltage may be expressed as "dV / dQ."

[0113] 7, the control unit 120 may select a point min in the reference differential profile RP where the differential voltage is minimum. Here, the capacitance corresponding to the point min may be 0.3. Therefore, the control unit 120 may select the reference capacitance as 0.3.

[0114] The control unit 120 can be configured to set a capacity interval equal to or less than the reference capacity as the reference capacity interval RQ.

[0115] 6, the control unit 120 may set the reference capacity range RQ to a capacity range of 0.3 or less. Specifically, since the capacity range of the battery bank is 0 to 1, the control unit 120 may set the reference capacity range RQ to a capacity range of 0 to 0.3. Note that the capacity range of 0 to 0.3 is a normalized capacity range relative to the actual capacity range of the battery bank.

[0116] The battery diagnostic device 100 may determine a peak included in the reference capacity section RQ as the target peak tp to diagnose the state of the battery bank based on unbalanced deterioration of the negative electrodes of the battery cells. That is, the reference capacity section RQ may be a capacity section that reflects the deterioration state of the negative electrodes. The deterioration state of the negative electrodes may be clearly expressed in the differential profile DP2. Therefore, the battery diagnostic device 100 may diagnose the state of the battery bank based on whether unbalanced deterioration has occurred in the negative electrodes of the plurality of battery cells included in the battery bank.

[0117] 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 recorded in 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 well-known means.

[0118] The recording unit 110 may also store data and programs necessary for each component of the battery diagnostic device 100 to perform its operations and functions, or data generated during the execution of its operations and functions. The recording unit 110 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 110 may also store program code defining processes executable by the control unit 120.

[0119] Hereinafter, an embodiment in which the control unit 120 diagnoses the state of the battery module will be described in detail.

[0120] The control unit 120 may be configured to calculate an abnormality ratio indicating the ratio of the plurality of battery banks in an abnormal state.

[0121] Specifically, the control unit 120 may calculate the ratio of the number of battery banks diagnosed as being in an abnormal state to the total number of the plurality of battery banks.

[0122] In one embodiment, it is assumed that the number of battery banks included in the battery module is N, and the number of battery banks diagnosed as being in an abnormal state is M. The control unit 120 may calculate the abnormality ratio by calculating the formula "M÷N" or "M÷N×100." The formula for calculating the abnormality ratio may be appropriately selected depending on the unit of the abnormality ratio to be calculated.

[0123] The control unit 120 may be configured to diagnose the state of the battery module as a normal state or an abnormal state based on the abnormality ratio.

[0124] For example, if the abnormality ratio is less than a predetermined critical ratio, the control unit 120 may diagnose the state of the battery module as normal. Conversely, if the abnormality ratio is equal to or greater than the critical ratio, the control unit 120 may diagnose the state of the battery module as abnormal.

[0125] The battery diagnostic device 100 can further diagnose the state of the battery module based on the states of the plurality of battery banks, i.e., the battery diagnostic device 100 can diagnose not only the state of each of the plurality of battery banks but also the state of the battery module.

[0126] The control unit 120 may be configured to change the charging conditions preset for the battery module if the state of the battery module is diagnosed as an abnormal state.

[0127] Specifically, if the state of the battery module is diagnosed as abnormal, the control unit 120 may be configured to relax the fast charging conditions of the battery module by reducing the maximum charging C rate preset for the battery module.

[0128] Here, the fast charging conditions refer to the conditions of the charging C rate that can be applied to the battery module.

[0129] If a battery module diagnosed as being in an abnormal state is continuously fast-charged, a lithium plating phenomenon, in which lithium metal is deposited on the surface of the negative electrode of the battery cell, may occur, accelerating the deterioration of the battery cell. Therefore, the control unit 120 may relax the fast-charge conditions to extend the life of the battery module.

[0130] In the embodiment of FIG. 3, when the control unit 120 diagnoses the state of the battery bank based on the differential profile DP1, the control unit 120 may be configured to reduce the set maximum charge C rate for voltage sections other than the reference voltage section RV among the entire voltage sections of the battery module.

[0131] In the embodiment of FIG. 6, when the control unit 120 diagnoses the state of the battery bank based on the differential profile DP2, the control unit 120 may be configured to reduce the set maximum charging C rate for other capacity ranges of the entire capacity range of the battery module, excluding the reference capacity range RQ.

[0132] For example, if the battery module is fully discharged, it is assumed that the fast charge condition for the battery module is set to 2C to fully charge the battery module within 30 minutes. That is, it is assumed that the maximum charge C rate for the battery module is set to 2C. If the state of the battery module is diagnosed as abnormal, the control unit 120 may reduce the maximum charge C rate set for the battery module from 2C to 1C.

[0133] The battery diagnostic device 100 can prevent accelerated deterioration of a battery module diagnosed as being in an abnormal state by reducing the maximum charge C rate set for the battery module. In addition, reducing the maximum charge C rate prevents deposition of lithium metal due to rapid charging. Therefore, various problems caused by the lithium plating phenomenon can be prevented in advance.

[0134] The battery diagnostic device 100 according to an embodiment of the present invention may be applied to a battery management system (BMS). That is, a 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 recording unit 110 and the control unit 120 of the battery diagnostic device 100 may be implemented as components of the BMS.

[0135] The battery diagnostic device 100 according to an embodiment of the present invention may be provided in a battery pack. That is, the battery pack according to the present invention may include the above-described battery diagnostic device 100 and one or more battery cells. The battery pack may further include electrical components (relays, fuses, etc.), a case, etc.

[0136] FIG. 8 is a diagram schematically illustrating an exemplary configuration of a battery pack 1 according to another embodiment of the present invention.

[0137] The battery module 10 may include multiple battery banks 11, 12, 13. For example, in the embodiment of Figure 8, the multiple battery banks 11, 12, 13 may be connected in series with each other.

[0138] The measuring unit 20 can measure the voltage of each of the plurality of battery banks 11, 12, and 13. The measuring unit 20 can also measure the voltage of the battery module 10.

[0139] The measurement unit 20 may be connected to a current measurement unit A. For example, the current measurement unit A may be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of the battery module 10. The measurement unit 20 may measure the charging current of the battery module 10 through the current measurement unit A to calculate the charged amount. The measurement unit 20 may also measure the discharging current of the battery module 10 through the current measurement unit A to calculate the discharged amount.

[0140] An external device can be connected to the positive terminal P+ and the negative terminal P- of the battery pack 1. For example, the external device can be a charging / discharging device, or a motor of an electric vehicle that receives power from the battery pack 1.

[0141] FIG. 9 is a diagram illustrating a battery diagnostic method according to yet another embodiment of the present invention.

[0142] Preferably, each step of the battery diagnostic method may be performed by the battery diagnostic device 100. Hereinafter, for convenience of explanation, the contents overlapping with the above explanation will be omitted or briefly explained.

[0143] The recording step S100 is a step of recording bank information regarding the voltage and capacity of each of a plurality of battery banks included in the battery module, and may be performed by the recording unit 110.

[0144] For example, the recording unit 110 may record a battery bank profile that indicates the correspondence between the voltage and capacity of each of a plurality of battery banks.

[0145] The differential profile generating step S200 is a step of generating differential profiles for each of a plurality of battery banks based on bank information, and may be performed by the control unit 120.

[0146] For example, in the embodiment of FIG. 3, the control unit 120 can generate a differential profile DP1 that indicates the correspondence between voltage and differential capacitance based on the bank information recorded in the recording unit 110.

[0147] As another example, in the embodiment of FIG. 6, the control unit 120 can generate a differential profile DP2 indicating the correspondence between capacitance and differential voltage based on the bank information recorded in the recording unit 110.

[0148] The target peak determination step S300 is a step of determining a target peak tp from each of the generated differential profiles, and can be executed by the control unit 120.

[0149] 3, it is assumed that the reference voltage range RV is preset to 3.4 V to 3.6 V. The control unit 120 may determine the first peak p1 as the first target peak tp1 and the second peak p2 as the second target peak tp2 among the multiple peaks (first peak p1, second peak p2, third peak p3, fourth peak p4, and fifth peak p5) included in the differential profile DP1.

[0150] 6, it is assumed that the reference capacity range RQ is preset to 0 to 0.3. The control unit 120 may determine the first peak p1 as the first target peak tp1 and the second peak p2 as the second target peak tp2 among the multiple peaks (first peak p1, second peak p2, third peak p3, and fourth peak p4) included in the differential profile DP2.

[0151] The diagnosis step S400 is a step of diagnosing the state of the corresponding battery bank based on the determined target peak tp, and can be executed by the control unit 120.

[0152] 3 to 5, the control unit 120 may diagnose the state of the battery bank as normal when the number of determined target peaks tp is equal to or less than the number of reference peaks rp included in the reference voltage section RV of the preset reference differential profile RP1. Conversely, the control unit 120 may diagnose the state of the battery bank as abnormal when the number of determined target peaks tp exceeds the number of reference peaks rp. Furthermore, the control unit 120 may be configured to diagnose the state of the corresponding battery bank as abnormal when the number of determined target peaks tp exceeds the number of reference peaks rp and the voltage difference between the target peaks tp is equal to or greater than a preset critical voltage.

[0153] 6 and 7, the control unit 120 may diagnose a battery bank state in which the number of determined target peaks tp is equal to or less than the number of reference peaks rp included in a predetermined reference capacity section RQ of the reference differential profile RP as a normal state. Conversely, the control unit 120 may diagnose a battery bank state in which the number of determined target peaks tp exceeds the number of reference peaks rp as an abnormal state. Furthermore, the control unit 120 may be configured to diagnose a corresponding battery bank state as an abnormal state when the number of determined target peaks tp exceeds the number of reference peaks rp and the capacity difference between the target peaks tp is equal to or greater than a predetermined threshold.

[0154] 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.

[0155] 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.

[0156] 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 for various modifications. [Explanation of symbols]

[0157] 1: Battery pack 10: Battery module 11, 12, 13: Battery bank 20: Measuring part 100: Battery diagnostic device 110: Recording section 120: Control unit

Claims

1. a recording unit configured to record bank information regarding the voltage and capacity of each of a plurality of battery banks included in the battery module; a control unit configured to generate a differential profile for each of the plurality of battery banks based on the bank information, determine a target peak from each of the generated differential profiles, and diagnose a state of the corresponding battery bank based on the determined target peak.

2. 2. The battery diagnostic device of claim 1, wherein the control unit is configured to generate a differential profile indicating a correspondence relationship between a capacity and a differential voltage of each of the plurality of battery banks, and to determine the target peak included in a predetermined reference voltage interval from each of the generated differential profiles.

3. The control unit diagnosing a state of the battery bank as normal when the number of the determined target peaks is equal to or less than the number of reference peaks included in the reference voltage section of a preset reference differential profile; a state of the battery bank in which the determined number of target peaks exceeds the number of reference peaks is diagnosed as an abnormal state; The battery diagnostic device according to claim 2 , wherein the reference differential profile is preset to indicate a correspondence relationship between the voltage and the differential capacity of a reference battery bank.

4. 4. The battery diagnostic device of claim 3, wherein the control unit is configured to diagnose a state of a corresponding battery bank as an abnormal state when the determined number of target peaks exceeds the number of reference peaks and a voltage difference between the target peaks is equal to or greater than a predetermined critical voltage.

5. 2. The battery diagnostic device of claim 1, wherein the control unit is configured to generate a differential profile indicating a correspondence relationship between a capacity and a differential voltage of each of the plurality of battery banks based on the bank information, and to determine a target peak included in a predetermined reference capacity interval from each of the generated differential profiles.

6. The control unit diagnosing a state of the battery bank as normal when the number of the determined target peaks is equal to or less than the number of reference peaks included in the reference capacity section of a preset reference differential profile; a state of the battery bank in which the determined number of target peaks exceeds the number of reference peaks is diagnosed as an abnormal state; 6. The battery diagnostic device according to claim 5, wherein the reference differential profile is preset to indicate a correspondence relationship between the capacity and the differential voltage of a reference battery bank.

7. 7. The battery diagnostic device according to claim 6, wherein the control unit is configured to diagnose a state of a corresponding battery bank as an abnormal state when the number of the determined target peaks exceeds the number of the reference peaks and a capacity difference between the target peaks is equal to or greater than a preset threshold.

8. 2. The battery diagnostic device according to claim 1, wherein the control unit is configured to calculate an abnormality ratio indicating a ratio of the plurality of battery banks in an abnormal state, and to diagnose the state of the battery module as a normal state or an abnormal state based on the abnormality ratio.

9. The control unit If the abnormal ratio is less than a predetermined critical ratio, the state of the battery module is diagnosed as the normal state; The battery diagnostic device according to claim 8 , wherein the device is configured to diagnose the state of the battery module as the abnormal state if the abnormal ratio is equal to or greater than the critical ratio.

10. The battery diagnostic device according to claim 8 , wherein the control unit is configured to change a charging condition preset for the battery module if the state of the battery module is diagnosed as an abnormal state.

11. 11. The battery diagnostic device according to claim 10, wherein the control unit is configured to, if the state of the battery module is diagnosed as an abnormal state, relax a fast charging condition of the battery module by reducing a maximum charging C rate preset for the battery module.

12. the control unit is configured to select a reference capacity having a minimum corresponding differential voltage from a preset reference differential profile for a reference battery bank, select a reference voltage corresponding to the reference capacity from a preset reference bank profile for the reference battery bank, and set a voltage section equal to or lower than the reference voltage as the reference voltage section; The reference differential profile is preset to indicate a correspondence relationship between the capacity and the differential voltage of a reference battery bank; The battery diagnostic device according to claim 2 , wherein the reference bank profile is preset to indicate a correspondence relationship between the voltage and capacity of the reference battery bank.

13. 6. The battery diagnostic device according to claim 5, wherein the control unit is configured to select a reference capacity having a minimum corresponding differential voltage from a preset reference differential profile, and set a capacity section equal to or less than the reference capacity as the reference capacity section.

14. A battery pack including the battery diagnostic device according to any one of claims 1 to 13.

15. a recording step of recording bank information regarding the voltage and capacity of each of a plurality of battery banks included in the battery module; generating a differential profile for each of the plurality of battery banks based on the bank information; a target peak determination step of determining a target peak from each of the generated differential profiles; and a diagnosis step of diagnosing the state of the corresponding battery bank based on the determined target peak.

Images