Battery diagnostic device and method

Abstract

A battery diagnostic method according to an aspect of the present invention comprises: a sampling step of sampling an OCV value of a target battery in a partial SOC range of the entire SOC range of the target battery; a generation step of generating, on the basis of OCV values sampled in the partial SOC range, an estimation profile obtained by estimating OCV values of the target battery, which correspond to the entire SOC range; and a diagnosis step of diagnosing the target battery on the basis of the estimation profile.

Description

Battery diagnostic device and method

[0001] This application claims priority from Korean Patent Application No. 10-2024-0007618, filed January 17, 2024, the entire disclosure of which is incorporated herein by reference.

[0002] The present invention relates to a battery diagnostic device and method, and more particularly, to a battery diagnostic device and method for diagnosing the state of a rechargeable battery.

[0003] Recently, as the demand for portable electronic products such as laptops, digital cameras, and mobile phones has rapidly increased and the development of electric vehicles, energy storage systems, robots, and satellites has been in full swing, research into high-performance batteries capable of repeated charging and discharging is actively being conducted.

[0004] Rechargeable batteries include lithium batteries that utilize lithium ions, such as lithium-ion batteries and lithium-ion polymer batteries, as well as nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. Among these, lithium batteries offer a relatively long lifespan due to minimal memory effect compared to nickel-based batteries, a very low self-discharge rate, and high energy density. Consequently, their application scope is gradually expanding.

[0005] The positive electrode and negative electrode of these batteries gradually deteriorate as the number of charge and discharge cycles of the battery increases, resulting in a decrease in electrical capacity.

[0006] However, existing technologies have the problem that battery diagnosis requires a lot of time and it is difficult to perform real-time diagnosis while the battery is in use because the battery is charged and discharged at a low current rate of about 0.05C (C-rate) to diagnose whether the battery is deteriorating and the battery condition is continuously measured to diagnose the battery condition.

[0007] In addition, the existing technology has a problem in that when the battery is charged and discharged with a high current rate of 0.3C or more in order to shorten the battery diagnosis time, the measured CCV of the battery includes overpotential, and the current state of the battery cannot be accurately diagnosed due to the influence of this overpotential.

[0008] The technical problem to be solved by the present invention is to provide a battery diagnosis device and method that shortens battery diagnosis time and enables diagnosis of a battery that is charged and discharged at a high current rate.

[0009] A battery diagnosis method according to one aspect of the present invention includes a sampling step of sampling an OCV (Open Circuit Voltage) value of a target battery in a partial SOC range among the entire SOC (State of Charge) range of the target battery; a generation step of generating an estimation profile that estimates OCV values ​​of the target battery corresponding to the entire SOC range based on the OCV values ​​sampled in the partial SOC range; and a diagnosis step of diagnosing the target battery based on the estimation profile.

[0010] In one embodiment, the sampling step may include sampling an OCV value of the target battery at each rest period of the target battery that occurs discontinuously in the SOC range while the target battery is being charged or discharged.

[0011] In one embodiment, the sampling step may include sampling the OCV value of the target battery a number of times corresponding to a predetermined reference number range in the partial SOC range.

[0012] In one embodiment, the generating step may include a first generating step of generating a second positive electrode profile and a second negative electrode profile corresponding to the sampled OCV values ​​based on a first positive electrode profile indicating a correspondence between the SOC and the positive electrode potential of a given reference battery and a first negative electrode profile indicating a correspondence between the SOC and the negative electrode potential of the reference battery before generating the estimated profile; and a second generating step of generating the estimated profile based on the second positive electrode profile and the second negative electrode profile.

[0013] In one embodiment, the first generating step may include generating the second anode profile and the second cathode profile by changing at least one of the position, scale, and shape of the first anode profile and the first cathode profile on a predetermined coordinate axis.

[0014] In one embodiment, the second generation step may include a step of generating the estimated profile by calculating the potential difference by SOC between the second positive electrode profile and the second negative electrode profile.

[0015] In one embodiment, the diagnosis step may include: obtaining an estimated positive electrode profile that estimates a correspondence between the SOC and the positive electrode potential of the target battery from the estimated profile, and an estimated negative electrode profile that estimates a correspondence between the SOC and the negative electrode potential of the target battery; and diagnosing the target battery using information included in at least one of the estimated positive electrode profile and the estimated negative electrode profile.

[0016] In one embodiment, the information includes at least one of a start potential, an end potential, and a shrinkage of the estimated anode profile, and a start potential, an end potential, and a shrinkage of the estimated cathode profile, wherein the shrinkage of the estimated anode profile may indicate a degree to which the estimated anode profile is shrinked in a predetermined direction compared to a predetermined reference anode profile, and the shrinkage of the estimated cathode profile may indicate a degree to which the estimated cathode profile is shrinked in a predetermined direction compared to a predetermined reference cathode profile.

[0017] In one embodiment, the method may further include a step of controlling the voltage of the target battery at full charge, or the current rate of the charging current or discharging current of the target battery, based on the diagnosis result of the diagnosis step.

[0018] According to another aspect of the present invention, a battery diagnosis device includes: an OCV sampling unit configured to sample an OCV (Open Circuit Voltage) value of a target battery in a partial SOC range among the entire SOC range of the target battery; an estimation profile generation unit configured to generate an estimation profile that estimates OCV values ​​of the target battery corresponding to the entire SOC range based on the OCV values ​​sampled in the partial SOC range; and a diagnosis unit configured to diagnose the target battery based on the estimation profile.

[0019] In one embodiment, the estimated profile generation unit may include a first generation module configured to generate a second positive electrode profile and a second negative electrode profile corresponding to the sampled OCV values ​​based on a first positive electrode profile indicating a correspondence between the SOC and the positive electrode potential of a predetermined reference battery, and a first negative electrode profile indicating a correspondence between the SOC and the negative electrode potential of the reference battery; and a second generation module configured to generate the estimated profile based on the second positive electrode profile and the second negative electrode profile.

[0020] In one embodiment, the first generation module may be configured to generate the second anode profile and the second cathode profile by changing at least one of the position, scale, and shape of the first anode profile and the first cathode profile on a predetermined coordinate axis.

[0021] In one embodiment, the second generation module may be configured to generate the estimated profile by calculating the SOC-specific potential difference between the second positive profile and the second negative profile.

[0022] A battery pack according to another aspect of the present invention includes the battery diagnostic device described above.

[0023] A vehicle according to another aspect of the present invention includes the battery diagnostic device described above.

[0024] According to the present invention, since diagnosis of a target battery is performed based on OCV values ​​of the target battery sampled from only a portion of the SOC range, rather than the entire SOC range of the target battery, diagnosis time can be shortened and diagnosis of a battery that is charged and discharged at a high current rate is enabled.

[0025] Additionally, since diagnosis is performed based on OCV values ​​sampled during use of the target battery, it enables real-time diagnosis of battery status and provision of rapid diagnosis results in onboard systems such as battery packs or battery management systems of electric vehicles.

[0026] In addition, since the diagnosis is performed based on an estimated profile generated by moving or modifying the positive and negative profiles of a given reference battery and combining them, the amount of computation required for the diagnosis can be reduced while ensuring the accuracy and reliability of the diagnosis results.

[0027] Furthermore, those skilled in the art will readily understand from the following description that various embodiments of the present invention can solve various technical problems not mentioned above.

[0028] FIG. 1 is a block diagram showing a battery diagnostic device according to one embodiment of the present invention.

[0029] Figure 2 is a diagram showing OCV values ​​sampled in some SOC ranges of the target battery.

[0030] Figure 3 is a diagram showing an OCV curve corresponding to the sampled OCV values ​​of Figure 2.

[0031] FIG. 4 is a diagram showing the anode profile and cathode profile corresponding to the sampled OCV values ​​of FIG. 2.

[0032] Fig. 5 is a drawing showing an estimated profile generated based on the positive and negative profiles of Fig. 4.

[0033] Figure 6 is a diagram showing information obtained based on an estimated profile.

[0034] Figure 7 is a flowchart illustrating a battery diagnosis method according to one embodiment of the present invention.

[0035] FIG. 8 is a drawing showing a battery pack according to one embodiment of the present invention.

[0036] Figure 9 is a drawing showing a vehicle according to one embodiment of the present invention.

[0037] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings to clarify solutions addressing the technical challenges of the present invention. However, if a description of a related known technology obscures the essence of the present invention, the description thereof may be omitted.

[0038] Additionally, the terms used in this specification are defined based on their functions within the present invention, and may vary depending on the intent or custom of the designer, manufacturer, etc. Therefore, the definitions of terms described below should be based on the contents throughout this specification.

[0039] FIG. 1 is a block diagram illustrating a battery diagnostic device (100) according to one embodiment of the present invention.

[0040] As illustrated in FIG. 1, a battery diagnostic device (100) according to one embodiment of the present invention is a device configured to diagnose the state of a rechargeable battery, and includes an OCV sampling unit (110), an estimated profile generation unit (120), and a diagnostic unit (130).

[0041] The battery (hereinafter, “target battery”) to be diagnosed by the battery diagnosis device (100) according to the present invention may be a battery cell corresponding to a basic unit of charging and discharging, a battery module in which multiple battery cells are connected in series and / or parallel, or a battery pack in which multiple battery cells or multiple battery modules are connected in series and / or parallel.

[0042] The above OCV sampling unit (110) is configured to sample the OCV (Open Circuit Voltage) value of the target battery in a part of the entire SOC (State of Charge) range of the target battery. For example, when the entire SOC range of the target battery is from 0[%] to 100[%], the OCV sampling unit (110) may be configured to sample the OCV value of the target battery in a part of the SOC range between 10[%] and 80[%]. For reference, the entire SOC range of the target battery may vary depending on the deterioration state of the target battery.

[0043] As will be described again below, the estimated profile generation unit (120) is configured to generate an estimated profile that estimates OCV values ​​of the target battery corresponding to the entire SOC range based on OCV values ​​sampled in the partial SOC range.

[0044] In addition, the diagnostic unit (130) is configured to diagnose the target battery based on the estimated profile. For example, the diagnostic unit (130) may be configured to diagnose the status of the target battery, such as the degree of degradation of the target battery, the positive / negative electrode capacity loss rate, and the available lithium loss rate, using information obtained from the estimated profile.

[0045] In one embodiment, the OCV sampling unit (110) may be configured to sample the OCV value of the target battery at each idle period of the target battery that occurs discontinuously within the SOC range while the target battery is being charged or discharged. In this case, the idle period of the target battery may be configured to occur when a specific condition is met or at predetermined times.

[0046] Additionally, in one embodiment, the OCV sampling unit (110) may be configured to sample the OCV value of the target battery a number of times corresponding to a predetermined reference number of times in the above-described SOC range.

[0047] If the number of samplings of the OCV sampling unit (110) is too small, the accuracy of the estimated profile generated by the estimated profile generation unit (120) may decrease. On the other hand, if the number of samplings is too large, the overall diagnosis time of the battery diagnosis device (100) may increase due to an increase in the amount of computation. Therefore, the number of samplings of the OCV sampling unit (110) must be appropriately determined so as to shorten the diagnosis time while ensuring the accuracy of the estimated profile.

[0048] Meanwhile, a portion of the SOC range within which the OCV value is sampled among the entire SOC range of the target battery may be determined by various factors, such as the usage status of the target battery, the SOC range or voltage range of the target battery in which charging and discharging frequently occurs, or the designer's intention.

[0049] In one embodiment, the OCV sampling unit (110) may be configured to sample the OCV value of the target battery in a portion of the voltage range between a predetermined first voltage and a second voltage among the entire voltage range of the target battery.

[0050] For example, if the entire voltage range of the target battery is from 2.5 [V] to 4.2 [V], the OCV sampling unit (110) may be configured to sample the OCV value of the target battery in a voltage range between 3.4 [V] and 4.05 [V].

[0051] As mentioned above, the estimated profile generation unit (120) can generate an estimated profile that estimates OCV values ​​corresponding to the entire SOC range of the target battery based on the OCV values ​​sampled in the partial SOC range. To this end, the estimated profile generation unit (120) can include a first generation module (122) and a second generation module (124).

[0052] The first generation module (122) may be configured to generate a second positive electrode profile and a second negative electrode profile corresponding to the sampled OCV values ​​based on a first positive electrode profile indicating a correspondence between the SOC and the positive electrode potential of a predetermined reference battery, and a first negative electrode profile indicating a correspondence between the SOC and the negative electrode potential of the reference battery. The reference battery may be a target battery at the beginning of life (BOL) point in time, or a battery in a normal state with the same configuration as the target battery.

[0053] In this case, the first generation module (122) may be configured to change at least one of the position, scale, and shape of the first positive profile and the first negative profile on a predetermined coordinate axis to generate the second positive profile and the second negative profile corresponding to the sampled OCV values.

[0054] That is, among various candidate anode profiles and candidate cathode profiles generated by moving or transforming the first anode profile and the first cathode profile on the SOC-OCV coordinate axis, the candidate anode profile and candidate cathode profile that, when combined with each other, generate a curve with the smallest error compared to the curve connecting the sampled OCV values ​​can be determined as the second anode profile and the second cathode profile described above.

[0055] The second generation module (124) may be configured to generate the estimated profile based on the second positive profile and the second negative profile.

[0056] In this case, the second generation module (124) may be configured to generate the estimated profile by calculating the potential difference for each SOC between the second positive electrode profile and the second negative electrode profile.

[0057] As a result, the diagnostic unit (130) can diagnose the target battery based on the estimated profile.

[0058] For example, the diagnostic unit (130) can obtain an estimated positive electrode profile that estimates the correspondence between the SOC of the target battery and the positive electrode potential from the estimated profile, and an estimated negative electrode profile that estimates the correspondence between the SOC of the target battery and the negative electrode potential.

[0059] Next, the diagnostic unit (130) can diagnose the target battery using diagnostic information included in at least one of the estimated positive electrode profile and the estimated negative electrode profile. The diagnostic information can include at least one of the starting potential, the ending potential, and the shrinkage of the estimated positive electrode profile, and the starting potential, the ending potential, and the shrinkage of the estimated negative electrode profile.

[0060] The degree of shrinkage of the above estimated bipolar profile indicates the degree to which the estimated bipolar profile shrinks in a predetermined direction compared to a predetermined reference bipolar profile.

[0061] Additionally, the degree of shrinkage of the estimated cathode profile indicates the degree to which the estimated cathode profile shrinks in a predetermined direction compared to a predetermined reference cathode profile.

[0062] For example, the diagnostic unit (130) may be configured to diagnose the target battery by comparing the diagnostic information with pre-stored reference information. In this case, the reference information may be information included in a reference positive electrode profile indicating a correspondence between the SOC and the positive electrode potential of a given reference battery, and a reference negative electrode profile indicating a correspondence between the SOC and the negative electrode potential of the reference battery. That is, the reference information may include at least one of a start potential, an end potential, and a shrinkage of the reference positive electrode profile, and a start potential, an end potential, and a shrinkage of the reference negative electrode profile.

[0063] The above reference battery may be a target battery at the BOL point in time, or a battery in normal condition with the same configuration as the target battery.

[0064] In one embodiment, the battery diagnostic device (100) may further include a charge / discharge control unit (140).

[0065] The above charge / discharge control unit (140) may be configured to control the voltage at full charge of the target battery, or the current rate of the charge / discharge current of the target battery, based on the diagnosis result of the above-described diagnosis unit (130). For example, if the target battery is diagnosed as deteriorated, the charge / discharge control unit (140) may control a charge / discharge unit (not shown) that charges / discharges the target battery to lower the voltage at full charge of the target battery, or reduce the current rate of the charge / discharge current.

[0066] The OCV sampling unit (110), estimated profile generation unit (120), diagnostic unit (130), and charge / discharge control unit (140) of the above-described battery diagnostic device (100) may be implemented as a combination of a processor and a program executed through the processor. The battery diagnostic device (100) may be implemented as a single processor, or as two or more processors that are interconnected.

[0067] In one embodiment, the battery diagnostic device (100) according to the present invention can be configured to be linked with various sensors, such as a voltage sensor (12a) that senses the voltage of the battery, a current sensor (12b) that senses the charge / discharge current of the battery, etc.

[0068] In addition, the battery diagnostic device (100) according to the present invention may be configured to interwork with a communication unit (14) that performs communication with another device located remotely. This communication unit (14) may be configured to receive data transmitted from a remote server or communication terminal via a wired / wireless communication network and transmit the data to the battery diagnostic device (100), or to transmit data generated in the battery diagnostic device (100) to another server or communication terminal. To this end, the communication unit (14) may include a communication modem that performs wired / wireless communication.

[0069] In addition, the battery diagnostic device (100) according to the present invention may be configured to be linked with a storage unit (16) capable of storing programs or data required for battery diagnosis. In this case, the storage unit (16) may include one or two or more types of recording media such as RAM, ROM, EEPROM, flash memory, registers, etc.

[0070] In another embodiment, the battery diagnostic device (100) according to the present invention may be configured to include one or two or more of the voltage sensor (12a), current sensor (12b), communication unit (14), and storage unit (16) described above.

[0071] Figure 2 is a diagram showing OCV values ​​sampled in some SOC ranges of the target battery.

[0072] As illustrated in FIG. 2, the OCV sampling unit (110) can sample the OCV value of the target battery in a portion of the SOC range (ΔSOC') among the entire SOC range (ΔSOC) of the target battery.

[0073] For example, the OCV sampling unit (110) can sample the OCV value of the target battery at each rest period of the target battery that occurs discontinuously in the partial SOC range (ΔSOC') while the target battery is being charged or discharged.

[0074] In this case, the SOC range within which the OCV value is sampled from the entire SOC range of the target battery may be determined by various factors, such as the usage status of the target battery, the SOC range or voltage range of the target battery where charging and discharging frequently occur, or the designer's intention. In addition, the target battery's idle period may be configured to occur when a specific condition is met or at predetermined intervals.

[0075] In one embodiment, the OCV sampling unit (110) may be configured to sample the OCV value of the target battery in a portion of the voltage range between a predetermined first voltage (V1) and a second voltage (V2) among the entire voltage range of the target battery.

[0076] In addition, the OCV sampling unit (110) can sample the OCV value of the target battery a number of times corresponding to a predetermined reference number of times in some SOC range (ΔSOC').

[0077] The above-mentioned estimated profile generation unit (120) can generate an estimated profile that estimates the OCV values ​​of the target battery corresponding to the entire SOC range (ΔSOC) based on the OCV values ​​sampled as described above.

[0078] Figure 3 is a diagram showing an OCV curve corresponding to the sampled OCV values ​​of Figure 2.

[0079] As illustrated in FIG. 3, the estimated profile generation unit (120) can obtain an OCV curve (E1) that partially represents the correspondence between the SOC and OCV of the target battery by connecting OCV values ​​sampled in some SOC range (ΔSOC').

[0080] Next, the estimated profile generation unit (120) can generate a positive profile and a negative profile corresponding to the sampled OCV values.

[0081] FIG. 4 is a diagram showing the anode profile and cathode profile corresponding to the sampled OCV values ​​of FIG. 2.

[0082] As illustrated in FIG. 4, the first generation module (122) of the estimated profile generation unit (120) can generate a second positive electrode profile (P2) and a second negative electrode profile (N2) corresponding to the sampled OCV values ​​based on a first positive electrode profile (P1) indicating a correspondence between the SOC and the positive electrode potential of a predetermined reference battery, and a first negative electrode profile (N1) indicating a correspondence between the SOC and the negative electrode potential of the reference battery. The reference battery may be a target battery at the BOL (Beginning of Life) point in time, or a battery in a normal state having the same configuration as the target battery.

[0083] In this case, the first generation module (122) can change at least one of the position, scale, and shape of the first anode profile (P1) and the first cathode profile (N1) on the SOC-OCV coordinate axis to generate the second anode profile (P2) and the second cathode profile (N2) corresponding to the sampled OCV values.

[0084] For example, the first generation module (122) may determine, among various candidate anode profiles and candidate cathode profiles generated by moving or transforming the first anode profile (P1) and the first cathode profile (N1) on the SOC-OCV coordinate axis, the candidate anode profile and candidate cathode profile that, when combined with each other, generate a curve with the smallest error compared to the OCV curve (E1) connecting the sampled OCV values, as the second anode profile (P2) and the second cathode profile (N2).

[0085] Next, the second generation module (124) of the estimated profile generation unit (120) can generate an estimated profile that shows the correspondence between the SOC and OCV of the target battery in the entire SOC range (ΔSOC) of the target battery based on the second positive electrode profile (P2) and the second negative electrode profile (N2).

[0086] FIG. 5 is a drawing showing an estimated profile (E2) generated based on the second positive profile (P2) and the second negative profile (N2) illustrated in FIG. 4.

[0087] As illustrated in FIG. 5, the second generation module (124) can generate the estimated profile (E2) by calculating the potential difference for each SOC between the second positive electrode profile (P2) and the second negative electrode profile (N2).

[0088] Next, the diagnostic unit (130) can diagnose the target battery based on the estimated profile (E2).

[0089] Figure 6 is a diagram showing information obtained based on an estimated profile.

[0090] As illustrated in FIG. 6, the diagnostic unit (130) can obtain an estimated positive electrode profile (EP) that estimates the correspondence between the SOC of the target battery and the positive electrode potential, and an estimated negative electrode profile (EN) that estimates the correspondence between the SOC of the target battery and the negative electrode potential, from the estimated profile (E2).

[0091] In one embodiment, the estimated positive electrode profile (EP) can be obtained by extracting a section corresponding to the entire SOC range of the target battery from the second positive electrode profile (P2) used to generate the estimated profile (E2).

[0092] Additionally, the estimated negative profile (EN) can be obtained by extracting a section corresponding to the entire SOC range of the target battery from the second negative profile (N2) used to generate the estimated profile (E2).

[0093] In this case, the overall SOC range of the target battery can be defined as the range between the minimum SOC value corresponding to the voltage (V1') when the target battery is fully discharged and the maximum SOC value corresponding to the voltage (V2') when the target battery is fully charged.

[0094] In another embodiment, the estimated positive profile (EP) and the estimated profile (E2) may be obtained through a simulation that finds the positive profile and the negative profile that, by mutual combination, produce a profile most similar to the estimated profile (E2).

[0095] Next, the diagnostic unit (130) can diagnose the target battery using diagnostic information included in at least one of the estimated positive profile (EP) and the estimated profile (E2). The diagnostic information can include at least one of the starting potential (pi), the ending potential (pf), and the shrinkage (ps) of the estimated positive profile (EP), and the starting potential (ni), the ending potential (nf), and the shrinkage (ns) of the estimated negative profile (EN).

[0096] Here, the shrinkage (ps) of the estimated bipolar profile (EP) represents the degree to which the estimated bipolar profile (EP) shrinks in the SOC axis direction compared to a predetermined reference bipolar profile.

[0097] Additionally, the shrinkage (ns) of the estimated cathode profile (EN) indicates the degree to which the estimated cathode profile (EN) shrinks in the SOC axis direction compared to a given reference cathode profile.

[0098] Next, the diagnostic unit (130) can diagnose the target battery by comparing the diagnostic information with pre-stored reference information. In this case, the reference information may be information included in a reference positive electrode profile indicating a correspondence between the SOC and positive electrode potential of a given reference battery, and a reference negative electrode profile indicating a correspondence between the SOC and negative electrode potential of the reference battery.

[0099] That is, the reference information may include at least one of the starting potential, the ending potential, and the shrinkage of the reference anode profile, and the starting potential, the ending potential, and the shrinkage of the reference cathode profile.

[0100] The above reference battery may be a target battery at the BOL point in time, or a battery in normal condition with the same configuration as the target battery.

[0101] Figure 7 is a flowchart illustrating a battery diagnosis method according to one embodiment of the present invention.

[0102] As illustrated in FIG. 7, the battery diagnosis method according to the present invention is a method for diagnosing a rechargeable battery, and can be performed by a processor.

[0103] In addition, the target battery to be diagnosed in the battery diagnosis method according to the present invention may be a battery cell corresponding to a basic unit of charge and discharge, a battery module in which multiple battery cells are connected in series and / or parallel, or a battery pack in which multiple battery cells or multiple battery modules are connected in series and / or parallel.

[0104] First, the processor samples the OCV value of the target battery in a portion of the entire SOC range of the target battery (S10).

[0105] For example, the processor may sample the OCV value of the target battery at each of the target battery's rest periods, which occur discontinuously within the SOC range, while the target battery is being charged or discharged.

[0106] In this case, the SOC range within which the OCV value is sampled from the entire SOC range of the target battery may be determined by various factors, such as the usage status of the target battery, the SOC range or voltage range of the target battery where charging and discharging frequently occur, or the designer's intention. In addition, the target battery's idle period may be configured to occur when a specific condition is met or at predetermined intervals.

[0107] In one embodiment, the processor may be configured to sample an OCV value of the target battery in a portion of a voltage range between a predetermined first voltage and a second voltage within the entire voltage range of the target battery.

[0108] Additionally, the processor can sample the OCV value of the target battery a number of times corresponding to a predetermined reference number range in some SOC range.

[0109] Next, the processor can generate an estimated profile that estimates the OCV values ​​of the target battery corresponding to the entire SOC range based on the OCV values ​​sampled as described above (S20).

[0110] As described with respect to FIG. 3, the processor can obtain an OCV curve (E1) that partially represents the correspondence between the SOC and OCV of the target battery by connecting the OCV values ​​sampled in some SOC range (ΔSOC').

[0111] Next, the processor can generate positive and negative profiles corresponding to the sampled OCV values.

[0112] As described with reference to FIG. 4, the processor may generate a second positive electrode profile (P2) and a second negative electrode profile (N2) corresponding to the sampled OCV values ​​based on a first positive electrode profile (P1) indicating a correspondence between the SOC and the positive electrode potential of a given reference battery, and a first negative electrode profile (N1) indicating a correspondence between the SOC and the negative electrode potential of the reference battery. The reference battery may be a target battery at the beginning of life (BOL) point in time, or a battery in a normal state having the same configuration as the target battery.

[0113] In this case, the processor can change at least one of the position, scale, and shape of the first anode profile (P1) and the first cathode profile (N1) on the SOC-OCV coordinate axis to generate the second anode profile (P2) and the second cathode profile (N2) corresponding to the sampled OCV values.

[0114] For example, the processor may determine, among various candidate anode profiles and candidate cathode profiles generated by moving or transforming the first anode profile (P1) and the first cathode profile (N1) on the SOC-OCV coordinate axis, the candidate anode profile and candidate cathode profile that, when combined with each other, generate a curve with the smallest error compared to the OCV curve (E1) connecting the sampled OCV values, as the second anode profile (P2) and the second cathode profile (N2).

[0115] Next, the processor can generate an estimated profile (E2) representing a correspondence between the SOC and OCV of the target battery over the entire SOC range of the target battery, based on the second positive profile (P2) and the second negative profile (N2).

[0116] As described with respect to FIG. 5, the processor can generate the estimated profile (E2) by calculating the potential difference for each SOC between the second positive profile (P2) and the second negative profile (N2).

[0117] Next, the processor can diagnose the target battery based on the estimated profile (E2) (S30).

[0118] As described in connection with FIG. 6, the processor can obtain an estimated positive electrode profile (EP) that estimates a correspondence between the SOC of the target battery and the positive electrode potential, and an estimated negative electrode profile (EN) that estimates a correspondence between the SOC of the target battery and the negative electrode potential, from the estimated profile (E2).

[0119] In one embodiment, the estimated positive electrode profile (EP) can be obtained by extracting a section corresponding to the entire SOC range of the target battery from the second positive electrode profile (P2) used to generate the estimated profile (E2).

[0120] Additionally, the estimated negative profile (EN) can be obtained by extracting a section corresponding to the entire SOC range of the target battery from the second negative profile (N2) used to generate the estimated profile (E2).

[0121] In this case, the overall SOC range of the target battery can be defined as the range between the minimum SOC value corresponding to the voltage (V1') when the target battery is fully discharged and the maximum SOC value corresponding to the voltage (V2') when the target battery is fully charged.

[0122] In another embodiment, the estimated positive profile (EP) and the estimated profile (E2) may be obtained through a simulation that finds the positive profile and the negative profile that, by mutual combination, produce a profile most similar to the estimated profile (E2).

[0123] Next, the processor can diagnose the target battery using diagnostic information included in at least one of the estimated positive profile (EP) and the estimated profile (E2). The diagnostic information can include at least one of the starting potential (pi), the ending potential (pf), and the shrinkage (ps) of the estimated positive profile (EP), and the starting potential (ni), the ending potential (nf), and the shrinkage (ns) of the estimated negative profile (EN).

[0124] Here, the shrinkage (ps) of the estimated bipolar profile (EP) represents the degree to which the estimated bipolar profile (EP) shrinks in the SOC axis direction compared to a predetermined reference bipolar profile.

[0125] Additionally, the shrinkage (ns) of the estimated cathode profile (EN) indicates the degree to which the estimated cathode profile (EN) shrinks in the SOC axis direction compared to a given reference cathode profile.

[0126] Next, the processor can diagnose the target battery by comparing the diagnostic information with pre-stored reference information. In this case, the reference information may be information included in a reference anode profile indicating a correspondence between the SOC and the anode potential of a given reference battery, and a reference cathode profile indicating a correspondence between the SOC and the cathode potential of the reference battery.

[0127] That is, the reference information may include at least one of the starting potential, the ending potential, and the shrinkage of the reference anode profile, and the starting potential, the ending potential, and the shrinkage of the reference cathode profile.

[0128] The above reference battery may be a target battery at the BOL point in time, or a battery in normal condition with the same configuration as the target battery.

[0129] Next, the processor can adjust the voltage at full charge of the target battery, or the current rate of the charging or discharging current of the target battery, based on the diagnosis results for the target battery (S40, S50). For example, if the target battery is diagnosed as deteriorated, the processor can control a charging / discharging unit (not shown) that charges / discharges the target battery to lower the voltage at full charge of the target battery, or reduce the current rate of the charging / discharging current.

[0130] The above processor can repeat the above-described processes (S10 to S50) until the use of the target battery is stopped (S60).

[0131] FIG. 8 is a drawing showing a battery pack (10) according to one embodiment of the present invention.

[0132] As illustrated in FIG. 8, the battery pack (10) includes a rechargeable battery (B) and a battery diagnostic device (100) according to the present invention. In one embodiment, the battery pack (10) may optionally further include a measuring unit (12), a communication unit (14), a storage unit (16), and a charging / discharging unit (18).

[0133] The above measurement unit (12) may be configured to measure the voltage and / or current of the battery (B). To this end, the measurement unit (12) may include a voltage sensor (12a) and a current sensor (12b) described with reference to FIG. 1.

[0134] This measuring unit (12) can measure the voltage of the battery (B) through the first sensing line (SL1) and the second sensing line (SL2). In addition, the measuring unit (12) can measure the current of the battery (B) through the third sensing line (SL3) connected to the current measuring circuit (A). The current measuring circuit (A) may include a shunt resistor.

[0135] A battery diagnostic device (100) according to one embodiment of the present invention can sample OCV values ​​of a battery (B) through the measuring unit (12).

[0136] The above communication unit (14) may be configured to perform communication with another device located remotely. For example, the communication unit (14) may be configured to receive data transmitted from a remote server or communication terminal via a wired / wireless communication network and transmit the data to the battery diagnosis device (100), or to transmit data generated in the battery diagnosis device (100) to another server or communication terminal. To this end, the communication unit (14) may include a communication modem that performs wired / wireless communication.

[0137] The above storage unit (16) may be configured to store programs or data required for battery diagnosis. In this case, the storage unit (16) may include one or more of various types of recording media, such as RAM, ROM, EEPROM, flash memory, registers, etc.

[0138] The above charging and discharging unit (18) may be configured to charge and / or discharge the battery (B). To this end, the charging and discharging unit (18) may include a charger for charging the battery (B), a discharger for discharging the battery (B), at least one switch for electrically connecting the battery (B) to terminals (T1, T2) of the battery pack (10), etc.

[0139] The battery diagnostic standby (100) according to one embodiment of the present invention can control the charging / discharging unit (18) to proceed or stop charging or discharging of the battery (B), set charging / discharging conditions, or change the set charging / discharging conditions.

[0140] Figure 9 is a drawing showing a vehicle according to one embodiment of the present invention.

[0141] As illustrated in FIG. 9, a vehicle (2) according to one embodiment of the present invention may include a battery pack (10) that provides electric energy required for the operation of the vehicle, and a battery diagnostic device (100) according to the present invention.

[0142] In this case, the battery diagnostic device (100) may be configured to be linked with an ECU (Electronic Control Unit) that controls the operation of the vehicle (2) or a BMS (Battery Management System) of the battery pack (10).

[0143] Additionally, the battery diagnostic device (100) may be configured to receive data transmitted from a remote server (4) via a wired / wireless communication network, or to transmit data generated in the battery diagnostic device (100) to the server (4).

[0144] For reference, the battery diagnostic device (100) according to the present invention can be applied to various electrical devices or electrical systems other than vehicles, and can also be applied to ESS (Energy Storage System).

[0145] As described above, according to the present invention, diagnosis of a target battery is performed based on OCV values ​​of the target battery sampled from only a portion of the SOC range, rather than the entire SOC range of the target battery, thereby shortening the diagnosis time and enabling diagnosis of a battery that is charged and discharged at a high current rate.

[0146] Additionally, since diagnosis is performed based on OCV values ​​sampled during use of the target battery, it enables real-time diagnosis of battery status and provision of rapid diagnosis results in onboard systems such as battery packs or battery management systems of electric vehicles.

[0147] In addition, since the diagnosis is performed based on an estimated profile generated by moving or deforming the positive and negative profiles of a given reference battery and combining them, the amount of computation required for the diagnosis can be reduced while ensuring the accuracy and reliability of the diagnosis results.

[0148] Furthermore, it goes without saying that embodiments according to the present invention can solve various technical problems other than those mentioned in the present specification, not only in the relevant technical field but also in related technical fields.

[0149] The present invention has been described with reference to specific embodiments. However, those skilled in the art will clearly understand that various modifications can be implemented within the technical scope of the present invention. Therefore, the embodiments disclosed above should be considered illustrative rather than limiting. In other words, the true scope of the present invention is set forth in the claims, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

[0150] [Explanation of symbols]

[0151] 2: Vehicle

[0152] 10: Battery pack

[0153] 100: Battery Diagnostic Device

[0154] 110: OCV sampling section

[0155] 120: Estimated profile generation unit

[0156] 130: Diagnostic Department

[0157] 140: Charge / discharge control unit

Claims

1. A battery diagnosis method performed by a processor, A sampling step of sampling an OCV (Open Circuit Voltage) value of the target battery in a portion of the entire SOC (State of Charge) range of the target battery; A generation step for generating an estimated profile that estimates OCV values of the target battery corresponding to the entire SOC range based on OCV values sampled in the above partial SOC range; and A battery diagnosis method comprising a diagnosis step of diagnosing the target battery based on the estimated profile.

2. In paragraph 1, A battery diagnosis method, characterized in that the sampling step includes a step of sampling an OCV value of the target battery at each rest period of the target battery that occurs discontinuously in the partial SOC range while the target battery is being charged or discharged.

3. In paragraph 1, A battery diagnosis method, characterized in that the sampling step includes a step of sampling the OCV value of the target battery a number of times corresponding to a predetermined reference number range in the partial SOC range.

4. In paragraph 1, The above generation steps are: Before generating the above-mentioned estimated profile, a first generation step of generating a second positive electrode profile and a second negative electrode profile corresponding to the sampled OCV values based on a first positive electrode profile indicating a correspondence between the SOC and the positive electrode potential of a given reference battery and a first negative electrode profile indicating a correspondence between the SOC and the negative electrode potential of the reference battery; and A battery diagnosis method, characterized by including a second generation step of generating the estimated profile based on the second positive electrode profile and the second negative electrode profile.

5. In paragraph 4, A battery diagnosis method, characterized in that the first generation step includes a step of generating the second positive electrode profile and the second negative electrode profile by changing at least one of the position, scale, and shape of the first positive electrode profile and the first negative electrode profile on a predetermined coordinate axis.

6. In paragraph 4, A battery diagnosis method, characterized in that the second generation step includes a step of generating the estimated profile by calculating the potential difference for each SOC between the second positive electrode profile and the second negative electrode profile.

7. In paragraph 1, The above diagnostic steps are: From the above estimated profile, a step of obtaining an estimated anode profile that estimates a correspondence between the SOC of the target battery and the anode potential, and an estimated cathode profile that estimates a correspondence between the SOC of the target battery and the cathode potential; and A battery diagnosis method, characterized by comprising a step of diagnosing the target battery using information included in at least one of the estimated positive electrode profile and the estimated negative electrode profile.

8. In paragraph 7, The above information includes at least one of the initiation potential, the end potential and the shrinkage of the estimated anode profile, and the initiation potential, the end potential and the shrinkage of the estimated cathode profile. The degree of shrinkage of the above estimated anode profile indicates the degree to which the estimated anode profile shrinks in a predetermined direction compared to a predetermined reference anode profile. A battery diagnosis method, characterized in that the degree of shrinkage of the estimated negative electrode profile indicates the degree to which the estimated negative electrode profile shrinks in a predetermined direction compared to a predetermined reference negative electrode profile.

9. In paragraph 1, A battery diagnosis method characterized by further including a step of controlling the voltage of the target battery at full charge, or the current rate of the charging current or discharging current of the target battery, according to the diagnosis result of the above diagnosis step.

10. An OCV sampling unit configured to sample an OCV (Open Circuit Voltage) value of the target battery in a portion of the entire SOC (State of Charge) range of the target battery; An estimation profile generation unit configured to generate an estimation profile that estimates OCV values of the target battery corresponding to the entire SOC range based on OCV values sampled in the above partial SOC range; and A battery diagnostic device including a diagnostic unit configured to diagnose the target battery based on the estimated profile.

11. In paragraph 10, The above estimated profile generation unit, A first generation module configured to generate a second positive electrode profile and a second negative electrode profile corresponding to the sampled OCV values based on a first positive electrode profile indicating a correspondence between the SOC and the positive electrode potential of a given reference battery and a first negative electrode profile indicating a correspondence between the SOC and the negative electrode potential of the reference battery; and A battery diagnostic device, characterized by including a second generation module configured to generate the estimated profile based on the second positive electrode profile and the second negative electrode profile.

12. In paragraph 11, A battery diagnostic device, characterized in that the first generation module is configured to generate the second positive electrode profile and the second negative electrode profile by changing at least one of the position, scale, and shape of the first positive electrode profile and the first negative electrode profile on a predetermined coordinate axis.

13. In paragraph 11, A battery diagnostic device, characterized in that the second generation module is configured to generate the estimated profile by calculating the potential difference for each SOC between the second positive electrode profile and the second negative electrode profile.

14. A battery pack comprising a battery diagnostic device according to any one of claims 10 to 13.

15. A vehicle including a battery diagnostic device according to any one of claims 10 to 13.

Images