Battery diagnostic device and method

Abstract

A battery diagnosis device according to an embodiment of the present invention includes a voltage measurement unit configured to measure a voltage of a battery during a process of discharging the battery; a pulse output unit configured to generate a discharge pulse at every predetermined period and output the generated discharge pulse to the battery; and a control unit configured to calculate a resistance value of the battery based on a voltage deviation of the battery due to the discharge pulse, determine a resistance pattern in a preset initial discharge section based on the calculated resistance value, and diagnose lithium deposition of the battery according to the determined resistance pattern.

Description

[Technical Field]

[0001] This application claims priority based on Korean Patent Application No. 10-2022-0066254, filed on May 30, 2022, the entire contents of which are incorporated herein by reference in their entirety in the specification and drawings thereof.

[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 a battery state. [Background technology]

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

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

[0005] While various research efforts are being made to improve the capacity and density of such batteries, improving their lifespan and safety is also important. To achieve this, it is necessary to suppress the decomposition reaction between the electrolyte and the electrode surface, and to prevent overcharging and overdischarging.

[0006] In particular, it is necessary to prevent the deposition of lithium 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 changes in the kinetic balance of the battery, resulting in battery degradation. Furthermore, the deposition of lithium metal on the surface of the negative electrode can cause an internal short circuit in the battery, which can lead to fire and explosion. Therefore, it is necessary to develop a technology that can detect the deposition of lithium metal on the surface of the negative electrode. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been devised to solve the above problems, and an object of the present invention is to provide a battery diagnostic device and method capable of diagnosing lithium deposition in a battery.

[0008] Other objects and advantages of the present invention will become apparent from the following description and the embodiments of the present invention, and can be realized by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0009] According to one aspect of the present invention, a battery diagnostic device includes: a voltage measurement unit configured to measure a voltage of a battery during a discharge process of the battery; a pulse output unit configured to generate a discharge pulse at predetermined intervals and output the generated discharge pulse to the battery; and a control unit configured to calculate a resistance value of the battery based on a voltage deviation of the battery due to the discharge pulse, determine a resistance pattern for a predetermined initial discharge period based on the calculated resistance value, and diagnose lithium deposition in the battery according to the determined resistance pattern.

[0010] The control unit may be configured to calculate resistance change rates for a plurality of target resistance values ​​included in the initial discharge period, compare the calculated resistance change rates with a preset reference change rate, and determine the resistance pattern as a first resistance pattern or a second resistance pattern based on a comparison result.

[0011] The control unit may be configured to calculate an average rate of change for a plurality of the target resistance values ​​included in the initial discharge period, and to calculate the calculated average rate of change as the rate of resistance change.

[0012] The control unit may be configured to determine the resistance pattern as the first resistance pattern if the calculated resistance change rate is less than the reference change rate.

[0013] The control unit may be configured to determine the resistance pattern as the second resistance pattern if the calculated resistance change rate is equal to or greater than the reference change rate.

[0014] The control unit may be configured to diagnose that lithium has been deposited in the battery if the resistance pattern is the first resistance pattern.

[0015] The pulse output unit may be configured to output the discharge pulse at a discharge start time when discharge of the battery begins.

[0016] The initial discharge period may be preset from a discharge start time when the discharge of the battery starts to a target time.

[0017] The target time point may be preset to a time point corresponding to a minimum resistance value from a start time point in a reference profile preset to correspond to the battery.

[0018] The control unit corresponds to the discharge pulse. Current value The resistance value of the battery may be calculated for each predetermined period based on the voltage deviation.

[0019] A battery pack according to another aspect of the present invention includes the battery diagnostic device according to an aspect of the present invention.

[0020] A motor vehicle according to yet another aspect of the present invention includes the battery diagnostic device according to an aspect of the present invention.

[0021] According to yet another aspect of the present invention, a battery diagnosis method includes: a voltage measuring step of measuring a voltage of a battery during a battery discharge process; a discharge pulse output step of generating discharge pulses at predetermined intervals and outputting the generated discharge pulses to the battery; a resistance value calculating step of calculating a resistance value of the battery based on a voltage deviation of the battery due to the discharge pulses; a resistance pattern determining step of determining a resistance pattern for a predetermined initial discharge section based on the calculated resistance value; and a diagnosis step of determining lithium deposition in the battery according to the determined resistance pattern. [Effects of the Invention]

[0022] According to one aspect of the present invention, a battery diagnostic device can diagnose the state of a battery based on a resistance change rate of the battery during an initial discharge period. That is, the battery diagnostic device can quickly diagnose lithium deposition in the battery by calculating the resistance value at the time of initial discharge of the battery.

[0023] Furthermore, according to one embodiment of the present invention, since the diagnosis is performed during the discharge process of the battery, that is, during the process of reducing the energy of the battery, lithium deposition in the battery can be safely diagnosed.

[0024] 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.

[0025] The following drawings attached to this specification, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention, and the present invention should not be interpreted as being limited to only the matters described in the drawings. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a diagram illustrating a battery diagnostic device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a diagram illustrating a discharge pulse according to an embodiment of the present invention. [Figure 3] 4A and 4B are diagrams illustrating a reference profile and a resistance profile of a first battery according to an embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged view of the S1 region in FIG. 3. [Figure 5] 10A and 10B are diagrams illustrating a reference profile and a resistance profile of a second battery according to an embodiment of the present invention. [Figure 6] FIG. 6 is an enlarged view of region S2 in FIG. 5. [Figure 7] 10 is a diagram schematically illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention. [Figure 8] FIG. 10 is a schematic diagram of a vehicle according to yet 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

[0027] The terms and words used in this specification and claims should not be interpreted limited to their ordinary and dictionary meanings, but should be interpreted in a meaning and concept that corresponds to the technical idea of ​​the present invention, in accordance with the principle that the inventor himself can appropriately define the concept of the term in order to explain the invention in the best way.

[0028] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiment of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted for them at the time of this application.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0034] FIG. 1 is a diagram illustrating a battery diagnostic device 100 according to an embodiment of the present invention.

[0035] Referring to FIG. 1, a battery diagnostic device 100 may include a voltage measuring unit 110, a pulse output unit 120, and a control unit .

[0036] Here, a battery refers to a physically separable, independent cell having a negative terminal and a positive terminal. For example, a lithium ion battery or a lithium polymer battery may be considered a battery. A battery may also refer to a battery module in which multiple cells are connected in series and / or parallel. Hereinafter, for convenience of explanation, a battery will be described as referring to a single independent cell.

[0037] The voltage measurement unit 110 may be configured to measure the voltage of the battery during the battery discharge process.

[0038] Specifically, the voltage measurement unit 110 may measure the voltage of the battery during the process of discharging the battery for each voltage measurement period.

[0039] The pulse output section 120 can be configured to generate a discharge pulse at every predetermined period.

[0040] Specifically, the pulse output unit 120 may be configured to generate a discharge pulse at predetermined intervals upon receiving a pulse generation signal from the control unit 130. The pulse output unit 120 may then stop generating the discharge pulse upon receiving a pulse generation end signal from the control unit 130.

[0041] For example, the pulse output section 120 may generate a DC pulse (Direct Current Pulse) at every predetermined period. As another example, the pulse output section 120 may generate an AC pulse (Alternating Current Pulse) at every predetermined period.

[0042] The pulse output unit 120 may be configured to output the generated discharge pulse to the battery.

[0043] Specifically, the pulse output unit 120 may output a discharge pulse to the negative electrode side of the battery through the pulse line PL. More specifically, the pulse output unit 120 may output a discharge pulse to the negative electrode side of the battery in a direction corresponding to the discharge direction of the battery.

[0044] Preferably, the pulse output unit 120 may be configured to output a discharge pulse at the start of discharge when the battery starts to discharge. For example, the pulse output unit 120 may output a discharge pulse at the same time that the battery starts to discharge. That is, since a change in the internal state of the battery is diagnosed from the start of discharge, the result of the battery state diagnosis may be a highly reliable result that adequately reflects the state of the battery.

[0045] FIG. 2 is a schematic diagram illustrating a discharge pulse according to one embodiment of the present invention.

[0046] 2, the pulse output unit 120 may generate and output a discharge pulse having a current value of k [mA] for each predetermined period T. The discharge pulses generated by the pulse output unit 120 may be the same. That is, the current amount of the discharge pulse may be the same. For example, the pulse output unit 120 may output a discharge pulse of 0.1 seconds for each minute. That is, the predetermined period T for outputting the discharge pulse is 1 minute, and a discharge pulse of 0.1 seconds may be output for each period.

[0047] 2, the time t0 at which the output of the discharge pulse begins may be the same as the time at which the battery discharge begins. That is, the pulse output unit 120 may output the discharge pulse at the time t0 at which the battery discharge begins. Therefore, the discharge of the battery and the output of the discharge pulse may begin simultaneously.

[0048] The control unit 130 may be configured to calculate the resistance value of the battery based on the voltage deviation of the battery due to the discharge pulse.

[0049] Specifically, the control unit 130 can calculate the internal resistance value of the battery based on the discharge pulse applied to the battery being discharged.

[0050] Preferably, the control unit 130 controls the discharge pulse. Current value The resistance value of the battery may be calculated at each predetermined period based on the voltage deviation.

[0051] Referring to FIG. 2, the amount of current of the discharge pulse can be calculated as k×Δt. For example, if the time during which the discharge pulse is applied is Δt, the amount of current of the discharge pulse can be calculated as k×Δt. Here, Δt may be the time difference between t0 and t1, the time difference between t2 and t3, or the time difference between t4 and t5. If the pulse output unit 120 outputs a 0.1-second discharge pulse every minute, Δt may be 0.1 seconds, and T may be 60 seconds.

[0052] Then, the control unit 130 may calculate the difference between the battery voltage at the start of the discharge pulse and the battery voltage at the end of the discharge pulse to calculate the battery voltage deviation due to the discharge pulse. For example, in the embodiment of FIG. 2, the control unit 130 may calculate the voltage deviation by calculating the difference between the battery voltage at time t0 and the battery voltage at time t1.

[0053] Finally, the control unit 130 uses Ohm's law to calculate Current value The control unit 130 may calculate the resistance value of the battery from the voltage deviation. For example, the control unit 130 may calculate the resistance value by calculating "R=ΔV÷ΔI", where R is the resistance value, ΔV is the voltage deviation, and ΔI is Current value It could be.

[0054] The control unit 130 may be configured to determine a preset resistance pattern for the initial discharge period based on the calculated resistance value.

[0055] Specifically, the control unit 130 may calculate a plurality of resistance values ​​during the discharge of the battery. The initial discharge interval may include the plurality of resistance values ​​calculated by the control unit 130. Here, the initial discharge interval refers to a time interval from the start of discharge to a predetermined time. The initial discharge interval will be described in detail later.

[0056] More specifically, the control unit 130 may be configured to calculate a resistance change rate for a plurality of target resistance values ​​included in the initial discharge section. Here, the target resistance value may refer to a resistance value that belongs to the initial discharge section among the plurality of resistance values ​​calculated by the control unit 130.

[0057] For example, the control unit 130 may be configured to calculate an average rate of change for a plurality of target resistance values ​​included in the initial discharge period, and may be configured to calculate the calculated average rate of change as the resistance change rate.

[0058] Fig. 3 is a diagram schematically illustrating a reference profile PR1 and a resistance profile P1 of a first battery according to an embodiment of the present invention, and Fig. 4 is a diagram illustrating an enlarged view of region S1 of Fig. 3. Specifically, Fig. 4 may be a diagram illustrating an enlarged view of a portion of the reference profile PR1 and the resistance profile P1.

[0059] First, the reference profile PR1 and the resistance profile P1 may be profiles indicating the correspondence relationship between resistance value and time. Specifically, the reference profile PR1 may be a profile preset for the first battery in a BOL (Beginning of Life) state or a reference battery for the first battery. The resistance profile P1 may be a profile generated by the control unit during the discharge process of the first battery. That is, the resistance profile P1 may be a profile indicating the resistance value calculated by the control unit over time.

[0060] 3, the control unit 130 may calculate the resistance value of the first battery at every predetermined period T during the discharge of the first battery. Then, the control unit 130 may calculate the average change rate in the initial discharge section D1. Specifically, the control unit 130 may calculate the change rate of the resistance value as a function of time between the initial discharge point (0 seconds) and point t1.

[0061] 4, the control unit 130 may calculate the resistance change rate for the first battery by calculating the formula "(r4-r3)÷(t1-0)." Here, since r3 and r4 are equal, the resistance change rate for the first battery may be 0.

[0062] The control unit 130 may be configured to compare the calculated resistance change rate with a preset reference change rate.

[0063] The control unit 130 can compare the calculated rate of resistance change with a preset reference rate of change to determine which is larger, i.e., whether the calculated rate of resistance change is less than the reference rate of change or greater than or equal to the reference rate of change.

[0064] Here, the reference change rate is a resistance change rate that serves as a reference for determining a resistance pattern of a battery, and may be set in advance. For example, the reference change rate may be set in advance to 0. As another example, the reference change rate may be set in advance to a value that is smaller than the resistance change rate according to the reference profile PR1 and is equal to or greater than 0. In the embodiment of FIG. 4, the reference change rate may be set in advance to "0" or "any value greater than 0 and less than (r2-r1)÷(t1-0)." Here, "(r2-r1)÷(t1-0)" is the resistance change rate for the first resistance profile PR1.

[0065] The control unit 130 may be configured to determine the resistance pattern as the first resistance pattern or the second resistance pattern based on the comparison result. Preferably, the control unit 130 may be configured to determine the resistance pattern as the first resistance pattern if the calculated resistance change rate is less than a reference change rate. Furthermore, the control unit 130 may be configured to determine the resistance pattern as the second resistance pattern if the calculated resistance change rate is equal to or greater than the reference change rate.

[0066] 3 and 4, it is assumed that the calculated resistance change rate and the reference resistance change rate are both 0. Because the resistance change rate is equal to or greater than the reference resistance change rate, the control unit 130 may determine the resistance pattern of the first battery as the second resistance pattern.

[0067] The control unit 130 may be configured to determine lithium deposition in the battery according to the determined resistance pattern.

[0068] For example, the control unit 130 may be configured to diagnose that lithium has been deposited in the battery if the resistance pattern is the first resistance pattern, and conversely, the control unit 130 may diagnose that lithium has not been deposited in the battery if the resistance pattern is the second resistance pattern.

[0069] For example, in the embodiments of Figures 3 and 4, it is assumed that the resistance pattern of the first battery is determined to be the second resistance pattern, and therefore the control unit 130 may diagnose that no lithium metal is deposited in the first battery.

[0070] According to an embodiment of the present invention, the battery diagnostic device 100 can diagnose the state of a battery based on the rate of change in resistance of the battery during the initial discharge period. That is, the battery diagnostic device 100 has an advantage of being able to quickly diagnose lithium deposition in the battery by calculating the resistance value at the time of initial discharge of the battery. Furthermore, because the diagnosis is performed during the battery discharge process, i.e., while the battery's energy is decreasing, the battery's lithium deposition can be safely diagnosed.

[0071] Meanwhile, the control unit 130 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 130 may be embodied as a collection of program modules. In this case, the program modules may be stored in a memory and executed by the control unit 130. The memory may be provided inside or outside the control unit 130 and may be connected to the control unit 130 by various known means.

[0072] The battery diagnostic device 100 may further include a recording unit 140. The recording unit 140 may store data and programs necessary for each component of the battery diagnostic device 100 to operate and function, or data generated during the operation and function. The recording unit 140 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 140 may also store program code defining processes executable by the control unit 130.

[0073] A reference profile and a reference change rate corresponding to the battery may be stored in advance in the recording unit 140. The control unit 130 may access the recording unit 140 to obtain the reference profile and the reference change rate. In addition, the voltage value measured by the voltage measuring unit 110 may be recorded in the recording unit 140.

[0074] Hereinafter, an embodiment in which the battery diagnostic device 100 diagnoses the state of the second battery will be described with reference to FIGS.

[0075] Figure 5 is a diagram schematically illustrating a reference profile PR2 and a resistance profile P2 of a second battery according to an embodiment of the present invention. Figure 6 is a diagram illustrating an enlarged view of region S2 in Figure 5. Specifically, Figure 6 may be a diagram illustrating an enlarged view of a portion of the reference profile PR2 and the resistance profile P2.

[0076] For example, in the embodiment of FIG. 6, the control unit 130 may calculate the resistance change rate for the second battery by calculating "(r4 - r3) / (t2 - 0)." Here, because r4 is greater than r3, the resistance change rate for the second battery may be calculated as a positive number. If the reference change rate for the second battery is set to 0, the calculated resistance change rate may be equal to or greater than the reference change rate. Therefore, the control unit 130 may determine the resistance pattern for the second battery as the second resistance pattern based on the comparison result. Then, the control unit 130 may diagnose that lithium is not deposited in the second battery based on the determined resistance pattern.

[0077] The initial discharge period set for each battery will now be described in detail.

[0078] The initial discharge period may be preset from a discharge start time when the battery starts discharging to a target time.

[0079] For example, in the embodiment of Fig. 3, a first initial discharge interval D1 for the first battery may be preset to 0 to t1, and in the embodiment of Fig. 5, a second initial discharge interval D2 for the second battery may be preset to 0 to t2.

[0080] That is, the initial discharge interval indicates a time interval for diagnosing the battery state, and therefore may be independently set to correspond to each battery. If the initial discharge interval is set collectively without considering the type of battery, the resistance change rate of the battery that appears in the initial discharge interval may not accurately represent the battery state. Therefore, the initial discharge interval may be set individually to correspond to each battery.

[0081] Specifically, the target time point can be preset to a time point corresponding to the minimum resistance value from the start time point in a reference profile preset to correspond to the battery.

[0082] For example, in the embodiment of FIG. 3, the target time may be t1. Referring to the enlarged view of FIG. 4, in the first reference profile PR1, the resistance value at the start of discharge (0 seconds) may be r1, and the minimum resistance value may be r2. Therefore, the target time may be t1, which corresponds to the minimum resistance value (r2). The initial discharge interval D1 for the first battery may be the time interval from the start of discharge (0 seconds) to the target time (t1). That is, the state of lithium deposition in the first battery may be most evident from 0 seconds to t1 seconds. Therefore, the control unit 130 may more accurately diagnose lithium deposition in the first battery based on the resistance change rate of the first battery in the initial discharge interval D1.

[0083] As another example, in the embodiment of FIG. 5, the target time may be t2. Referring to the enlarged view of FIG. 6, in the second reference profile PR2, the resistance value at the start of discharge (0 seconds) may be r1, and the minimum resistance value may be r2. Therefore, the target time may be t2, which corresponds to the minimum resistance value (r2). The initial discharge interval D2 for the second battery may be the time interval from the start of discharge (0 seconds) to the target time (t2). That is, the state of lithium deposition in the second battery may be most evident from 0 seconds to t2 seconds. Therefore, the control unit 130 may more accurately diagnose lithium deposition in the second battery based on the rate of change in resistance of the second battery during the initial discharge interval D2.

[0084] The battery diagnostic device 100 according to an embodiment of the present invention can accurately diagnose lithium deposition in a battery based on the resistance change rate in the initial discharge interval set for each battery. That is, since the initial discharge interval that allows accurate diagnosis of lithium deposition according to the initial discharge resistance change rate of the battery is set for each battery, the battery diagnostic device 100 can more accurately diagnose lithium deposition in the battery. In addition, since lithium deposition can be immediately diagnosed based on the resistance change rate in the initial discharge, there is an advantage in that the battery state can be quickly diagnosed.

[0085] The battery diagnostic device 100 according to the present invention may be applied to a battery management system (BMS). That is, the BMS according to the present invention may include the above-described battery diagnostic device 100. In this configuration, at least some of the components of the battery diagnostic device 100 may be implemented by complementing or adding functions of components included in a conventional BMS. For example, the voltage measurement unit 110, pulse output unit 120, control unit 130, and recording unit 140 of the battery diagnostic device 100 may be implemented as components of the BMS.

[0086] The battery diagnostic device 100 according to 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.

[0087] FIG. 7 is a diagram schematically illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention.

[0088] The positive terminal of battery B may be connected to the positive terminal P+ of the battery pack 10, and the negative terminal of battery B may be connected to the negative terminal P- of the battery pack 10.

[0089] The voltage measurement unit 110 may be connected to a first sensing line SL1 and a second sensing line SL2. Specifically, the voltage measurement unit 110 may be connected to a positive terminal of battery B via the first sensing line SL1 and to a negative terminal of battery B via the second sensing line SL2. The voltage measurement unit 110 may measure the voltage of battery B based on the voltages measured on the first sensing line SL1 and the second sensing line SL2.

[0090] For example, the voltage measurement unit 110 may measure the voltage of battery B while discharging battery B. Here, the voltage measurement unit 110 may measure the voltage of battery B while a discharge pulse is applied to battery B by the pulse output unit 120. Then, the control unit 130 may calculate the resistance value of battery B based on the voltage deviation of battery B due to the discharge pulse.

[0091] Meanwhile, a load (not shown) may have one end connected to the positive terminal P+ of the battery pack 10 and the other end connected to the negative terminal P- of the battery pack 10. Therefore, the positive terminal of battery B, the positive terminal P+ of the battery pack 10, the load, the negative terminal P- of the battery pack 10, and the negative terminal of battery B may be electrically connected. For example, the load may be a charging / discharging device or a motor of an electric vehicle that receives power from battery B.

[0092] FIG. 8 is a schematic diagram of a vehicle 1 according to yet another embodiment of the present invention.

[0093] 8, a battery diagnostic device 100 according to an embodiment of the present invention may be included in a vehicle 1 such as an electric vehicle (EV) or a hybrid vehicle (HV). Preferably, the battery diagnostic device 100 may be included in a battery pack 10, which may be included in the vehicle 1. The battery pack may then supply power to a motor through an inverter provided in the vehicle 1, thereby driving the vehicle 1.

[0094] For example, when the battery pack 10 included in the automobile 1 is discharging, the battery diagnostic device 100 can diagnose lithium deposition in the battery cells included in the battery pack by outputting a discharge pulse. That is, since the battery status can be diagnosed without a separate maintenance process, the battery status can be checked at any time. Furthermore, if lithium deposition is diagnosed in the battery, the information can be provided immediately.

[0095] FIG. 9 is a diagram illustrating a battery diagnostic method according to yet another embodiment of the present invention.

[0096] 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.

[0097] 9, the battery diagnosis method may include a voltage measurement step S100, a discharge pulse output step S200, a resistance value calculation step S300, a resistance pattern determination step S400, and a diagnosis step S500. In the embodiment of FIG. 9, the voltage measurement step S100 is followed by the discharge pulse output step S200, but preferably, the voltage measurement step S100 and the discharge pulse output step S200 may be performed simultaneously.

[0098] The voltage measuring step S100 is a step of measuring the voltage of the battery during the battery discharging process, and may be performed by the voltage measuring unit 110.

[0099] The discharge pulse output step S200 is a step of generating a discharge pulse at every predetermined period and outputting the generated discharge pulse to the battery, and may be performed by the pulse output unit 120.

[0100] For example, the voltage measurement unit 110 may measure the voltage of the battery during the battery discharge process. Preferably, the voltage measurement unit 110 may also measure the voltage of the battery when a discharge pulse is applied to the battery. Here, it is preferable that the output period T of the discharge pulse is preset to be equal to or longer than the voltage measurement period of the voltage measurement unit 110.

[0101] The resistance value calculation step S300 is a step of calculating the resistance value of the battery based on the voltage deviation of the battery due to the discharge pulse, and may be performed by the control unit 130.

[0102] For example, the control unit 130 knows information about the discharge pulse in advance. Current value Therefore, the control unit 130 knows the value of (ΔI) in advance. Current value Taking into account (ΔI) and the voltage deviation (ΔV) of the battery due to the discharge pulse, the resistance value (R) of the battery can be calculated.

[0103] The resistance pattern determining step S400 is a step of determining a resistance pattern for a preset initial discharge period based on the calculated resistance value, and can be performed by the control unit 130.

[0104] The control unit 130 may calculate an average change rate for a plurality of target resistance values ​​included in the initial discharge period to calculate a resistance change rate, and may compare the calculated resistance change rate with a preset reference change rate to determine a resistance pattern.

[0105] For example, if the calculated resistance change rate is less than the reference change rate, the control unit 130 may determine the resistance pattern as the first resistance pattern. Conversely, if the calculated resistance change rate is equal to or greater than the reference change rate, the control unit 130 may determine the resistance pattern as the second resistance pattern.

[0106] The diagnosis step S500 is a step of determining lithium deposition in the battery according to the determined resistance pattern, and may be performed by the control unit 130.

[0107] For example, the control unit 130 may be configured to diagnose that lithium has been deposited in the battery if the resistance pattern is the first resistance pattern, and may diagnose that lithium has not been deposited in the battery if the resistance pattern is the second resistance pattern.

[0108] 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.

[0109] 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.

[0110] 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]

[0111] 1: Automobiles 10: Battery pack 100: Battery diagnostic device 110: Voltage measurement unit 120: Pulse output section 130: Control unit 140: Recording section

Claims

1. A voltage measurement unit configured to measure the voltage of the battery during a discharge process of the battery discharging into a load; a pulse output unit configured to generate a discharge pulse corresponding to a discharge direction of the battery at every predetermined period and output the generated discharge pulse to the battery; a control unit configured to calculate a resistance value of the battery based on the current value of the discharge pulse and a voltage deviation of the battery, which is the difference between the voltage at the start of the discharge pulse and the voltage at the end of the discharge pulse, determine a resistance change rate in a predetermined initial discharge interval, which is a time interval from a discharge start point, which is the start point of a discharge process of the battery, to a predetermined time, based on the calculated resistance value, compare the determined resistance change rate with a predetermined reference change rate, and diagnose lithium deposition in the battery based on the comparison result.

2. The control unit The battery diagnostic device according to claim 1 , wherein the resistance change rate is calculated as a rate of change between the resistance value at the start of the discharge and the resistance value at the end of the initial discharge period.

3. The control unit 2. The battery diagnostic device according to claim 1, wherein the battery diagnostic device is configured to diagnose that lithium has precipitated in the battery if the calculated resistance change rate is less than the reference change rate.

4. The pulse output unit 2. The battery diagnostic device according to claim 1, wherein the device is configured to output the discharge pulse at the start of discharge.

5. The initial discharge section is 2. The battery diagnostic device according to claim 1, wherein the time interval is from the start of discharge to a time corresponding to a minimum resistance value in a reference profile preset to correspond to the battery.

6. The control unit 2. The battery diagnostic device according to claim 1, wherein the battery diagnostic device is configured to calculate a resistance value of the battery for each predetermined period based on a current value of the discharge pulse and the voltage deviation.

7. A battery pack comprising the battery diagnostic device according to any one of claims 1 to 6.

8. A vehicle powered by the battery pack of claim 7.

9. A voltage measurement step of measuring the voltage of the battery during a discharge process of the battery in which the battery is discharged to a load; a discharge pulse output step of generating a discharge pulse corresponding to a discharge direction of the battery at every predetermined period and outputting the generated discharge pulse to the battery; a resistance value calculation step of calculating a resistance value of the battery based on a current value of the discharge pulse and a voltage deviation of the battery, which is a difference between a voltage at a start point of the discharge pulse and a voltage at a finish point of the discharge pulse; determining a resistance change rate during a predetermined initial discharge period, which is a time period from a discharge start point, which is a start point of a discharge process of the battery, to a predetermined time, based on the calculated resistance value; a comparison step of comparing the determined resistance change rate with a preset reference change rate; and a diagnostic step of determining lithium deposition in the battery based on the comparison result.

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