Battery state estimation device and method

Abstract

A battery state estimation device according to one embodiment of the present invention includes a measurement unit configured to measure a charging current, a voltage and a temperature of the battery during a constant current charging process and a constant voltage charging process of the battery, and a control unit configured to determine whether or not the battery is behaving abnormally based on at least one behavior of the charging current, the voltage of the battery and the temperature of the battery during at least one of the constant current charging process and the constant voltage charging process, and to determine whether or not lithium deposition is occurring in the battery based on the determined whether or not the battery is behaving abnormally.

Description

[Technical Field]

[0001] This application claims priority based on Korean Patent Application No. 10-2021-0173264, filed on December 6, 2021, and the entire contents disclosed in the specification and drawings of that application are incorporated herein by reference.

[0002] The present invention relates to a battery state estimation device and method, and more particularly to a battery state estimation device and method capable of determining whether or not lithium deposition occurs in a battery. [Background technology]

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

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. Of 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] Although much research has been conducted on these batteries to increase their capacity and density, 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 phenomenon of lithium deposition on the surface of the anode (lithium plating). If lithium deposits on the surface of the anode, it 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 anode can cause an internal short circuit in the battery, which can lead to fire and explosion. Therefore, it is necessary to develop technology that can detect whether or not lithium metal has deposited on the surface of the anode. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been devised to solve the above-mentioned problems, and aims to provide a battery state estimation device and method that can check abnormal battery behavior and quickly determine whether or not lithium deposition has occurred.

[0008] Other objects and advantages of the present invention will become apparent from the following description and the accompanying drawings, in which: FIG. 1 is a block diagram of a semiconductor device according to an embodiment of the present invention; [Means for solving the problem]

[0009] A battery state estimation device according to one aspect of the present invention may include a measurement unit configured to measure a charging current, a voltage, and a temperature of the battery during a constant current charging process and a constant voltage charging process of the battery, and a control unit configured to determine whether or not the battery is behaving abnormally based on the behavior of at least one of the charging current, the voltage, and the temperature of the battery during at least one of the constant current charging process and the constant voltage charging process, and to determine whether or not lithium deposition is occurring in the battery based on the determined whether or not the battery is behaving abnormally.

[0010] The control unit may be configured to determine that lithium has been deposited in the battery when abnormal behavior of the battery is confirmed during either the constant current charging process or the constant voltage charging process.

[0011] The control unit may be configured to calculate a voltage change rate over time for each of the battery voltages measured by the measurement unit during the constant current charging process, and determine that the abnormal behavior has been confirmed if the calculated voltage change rate is less than a reference voltage change rate.

[0012] The controller may be configured to determine that the abnormal behavior has been confirmed if at least one of the voltage change rates calculated for each of the battery voltages is a negative number.

[0013] The control unit may be configured to calculate a temperature change rate over time for each of the temperatures of the battery measured by the measurement unit during the constant current charging process, and determine that the abnormal behavior has been confirmed if the calculated temperature change rate is equal to or greater than a reference temperature change rate within a predetermined period of time and the voltage change rate is less than a reference voltage change rate.

[0014] The control unit may be configured to calculate a current change rate over time for each of the battery currents measured by the measurement unit during the constant voltage charging process, and to determine that the abnormal behavior has been confirmed if the calculated current change rate exceeds a reference current change rate.

[0015] The controller may be configured to determine that the abnormal behavior is confirmed if at least one of the calculated current change rates for each of the battery currents is a positive number.

[0016] The control unit may be configured to calculate a temperature change rate over time for each of the battery temperatures measured by the measurement unit during the constant voltage charging process, and determine that the abnormal behavior has been confirmed if the calculated temperature change rate is equal to or greater than a reference temperature change rate within a predetermined period of time and the current change rate exceeds a reference current change rate.

[0017] The control unit may be configured to shut off charging and discharging of the battery when it is determined that the lithium has been deposited in the battery.

[0018] The control unit may be configured to first determine whether or not the battery behaves abnormally during the constant current charging process, and if no abnormal behavior of the battery is confirmed, determine whether or not the battery behaves abnormally during the constant voltage charging process.

[0019] A battery pack according to another aspect of the present invention may include the battery state estimation device according to one aspect of the present invention.

[0020] A battery state estimation method according to yet another aspect of the present invention may include a measurement step of measuring a charging current, a voltage, and a temperature of the battery during a constant current charging process and a constant voltage charging process of the battery; an abnormal behavior determination step of determining whether or not the battery is behaving abnormally based on the behavior of at least one of the charging current, the voltage of the battery, and the temperature of the battery during at least one of the constant current charging process and the constant voltage charging process; and a lithium deposition determination step of determining whether or not lithium deposition is occurring in the battery based on the presence or absence of abnormal behavior of the battery determined in the abnormal behavior determination step. [Effects of the Invention]

[0021] According to one aspect of the present invention, it is possible to determine whether or not lithium deposition has occurred in a battery in a non-destructive manner based on measurement information during the charging process of the battery, and to appropriately control the use of the battery based on the determination result.

[0022] Furthermore, according to one aspect of the present invention, it is possible to quickly determine whether or not lithium deposition has occurred in a battery based only on measurement information acquired during the charging process of the battery.

[0023] The effects of the present invention are not limited to those described above, and other effects not mentioned herein will be clearly understood by those skilled in the art from the claims.

[0024] The following drawings attached to this specification are intended to facilitate a further understanding of the technical concepts of the present invention together with the detailed description of the invention to be given later, and therefore the present invention should not be interpreted as being limited to the matters depicted in the drawings. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a diagram illustrating a battery state estimation device according to an embodiment of the present invention; [Figure 2] 1 is a diagram illustrating a battery charging process. [Figure 3] 4 is a diagram illustrating a charging process of a first battery according to an embodiment of the present invention; [Figure 4] FIG. 4 is a diagram illustrating a charging process of a second battery according to an embodiment of the present invention. [Figure 5] FIG. 10 is a diagram schematically illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention. [Figure 6] 10 is a diagram illustrating a battery state estimation method according to another embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in the specification and claims should not be construed as being limited to their ordinary or dictionary meanings, but should be construed as having meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventors themselves can appropriately define the concepts of terms in order to best explain the invention.

[0027] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted therefor at the time of this application.

[0028] Furthermore, in describing the present invention, if it is recognized that a specific description of related publicly known techniques may obscure the gist of the present invention, the detailed description will be omitted.

[0029] Terms including ordinal numbers such as first, second, etc. are used to distinguish one of various components from the other components, and are not used to limit the components by these terms.

[0030] Throughout this specification, when a part is said to "comprise" a certain element, this does not mean that it may further include other elements, unless otherwise specified.

[0031] Incidentally, throughout the specification, when a part is said to be "connected" to another part, this includes not only the case where it is "directly connected" to another part, but also the case where it is "indirectly connected" to another part via another element in between.

[0032] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0033] FIG. 1 is a diagram schematically illustrating a battery state estimating device 100 according to an embodiment of the present invention.

[0034] Referring to FIG. 1, a battery state estimating device 100 according to an embodiment of the present invention may include a measuring unit 110 and a control unit 120.

[0035] The measuring unit 110 may be configured to measure the charging current, the voltage and the temperature of the battery during a constant current charging process and a constant voltage charging process of the battery.

[0036] Here, a battery refers to a single independent cell that has a negative terminal and a positive terminal and can be physically separated. As an example, a 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. For ease of explanation, a battery will be described below as meaning a single independent cell.

[0037] FIG. 2 is a diagram showing a schematic diagram of the battery charging process.

[0038] Referring to FIG. 2, a typical battery charging process may include a constant current charging process and a constant voltage charging process.

[0039] A constant current charging process can be a process in which a battery is charged with a constant current until the battery voltage reaches a reference value. For example, in the embodiment of FIG. 2, the battery can be charged with a constant current between times 0 and t1. That is, the charging current is held constant between times 0 and t1, and the battery voltage can increase. At time t1, the battery voltage can reach the reference value.

[0040] A constant voltage charging process may be a process in which the battery is charged at a constant voltage after the battery voltage reaches a reference value. For example, in the embodiment of FIG. 2, the battery may be charged at a constant voltage after time t1. That is, after time t1, the battery voltage may be held constant and the charging current may be decreased. The constant voltage charging may be terminated when the decreasing charging current reaches a preset cutoff value.

[0041] The measurement unit 110 may be communicatively connected to the control unit 120. The measurement unit 110 may transmit measurement information, such as the measured charging current, battery voltage, and battery temperature, to the control unit 120.

[0042] The control unit 120 may be configured to determine whether or not the battery is behaving abnormally based on the behavior of at least one of the charging current, the battery voltage, and the battery temperature during at least one of the constant current charging process and the constant voltage charging process.

[0043] Here, the abnormal behavior may refer to a specific behavior of the charging current and / or the battery voltage and / or the battery temperature that does not appear during a normal constant current charging process and a normal constant voltage charging process of a battery.

[0044] For example, the embodiment of Figure 2 shows the charging current, battery voltage, and battery temperature in a normal constant current charging process and a normal constant voltage charging process of a battery. The control unit 120 may determine that abnormal battery behavior has occurred if the behavior of at least one of the charging current, battery voltage, and battery temperature differs from that of the embodiment of Figure 2. Details of the control unit 120 determining abnormal battery behavior in each of the constant current charging process and the constant voltage charging process will be described later.

[0045] The control unit 120 may be configured to determine whether or not lithium deposition occurs in the battery based on the determined presence or absence of abnormal battery behavior.

[0046] Specifically, if abnormal battery behavior is confirmed, the control unit 120 may determine that lithium metal has been deposited on the battery. More specifically, the control unit 120 may determine that lithium metal has been deposited on the surface of the negative electrode of the battery.

[0047] Generally, the deposition of lithium metal on the surface of the negative electrode may cause an internal short circuit in the battery, which may result in a risk of fire, explosion, etc. Therefore, the control unit 120 may be configured to shut down charging and discharging of the battery when it is determined that lithium has been deposited on the battery.

[0048] That is, the control unit 120 determines whether or not lithium deposition has occurred based on abnormal behavior of the battery during the constant current charging process and the constant voltage charging process of the battery, and can shut down the use of the battery if it is determined that lithium deposition has occurred.

[0049] The battery state estimating device 100 according to an embodiment of the present invention can determine whether or not lithium deposition has occurred in a battery in a non-destructive manner based on measurement information during the charging process of the battery, and control the use of the battery.

[0050] Furthermore, the battery state estimating device 100 has the advantage that it does not require measurement information acquired during multiple charging processes to determine whether lithium deposition has occurred in the battery, since it determines whether lithium deposition has occurred in the battery based on measurement information acquired during the charging process. In other words, the battery state estimating device 100 has the advantage that it can quickly determine whether lithium deposition has occurred in the battery using only measurement information acquired during one charging cycle.

[0051] In addition, the battery state estimating device 100 can determine whether or not lithium deposition has occurred in the battery by analyzing measurement information acquired in one charging cycle, and therefore does not require a machine learning method or the like for processing big data. Therefore, the battery state estimating device 100 has the advantage of being able to determine whether or not lithium deposition has occurred in the battery even with limited system resources.

[0052] Meanwhile, the control unit 120 disposed in the battery state estimating device 100 may selectively include a processor, an application-specific integrated circuit (ASIC), other chipsets, logic circuits, registers, a communication modem, a data processing device, and the like, known in the art, for executing various control logics performed in the present invention. Furthermore, when the control logic is implemented by software, the control unit 120 may be implemented by a collection of program modules. In this case, the program modules may be stored in memory and executed by the control unit 120. The memory may be internal or external to the control unit 120 and may be connected to the well-known control unit 120.

[0053] The battery state estimation device 100 may further include a memory unit 130. The memory unit 130 may store data and programs required for each component of the battery state estimation device 100 to operate and function, or data generated during the operation and function. The memory unit 130 may be any known information storage means known to be capable of recording, erasing, updating, and reading data. For example, the information storage means may include a random access memory (RAM), a flash memory, a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a register, etc. The memory unit 130 may also store program code defining processes that can be activated by the control unit 120.

[0054] The control unit 120 may be configured to determine that lithium has been deposited in the battery when abnormal battery behavior is confirmed during either the constant current charging process or the constant voltage charging process.

[0055] For example, if abnormal behavior of the battery is confirmed during a constant current charging process and / or a constant voltage charging process, the control unit 120 may determine that lithium has been deposited in the battery.

[0056] Preferably, the control unit 120 may be configured to first determine whether or not the battery is behaving abnormally during the constant current charging process, and if no abnormal battery behavior is confirmed, to determine whether or not the battery is behaving abnormally during the constant voltage charging process.

[0057] 2, the battery may be charged first through a constant current charging process and then through a constant voltage charging process. Therefore, the control unit 120 may determine whether the battery behaves abnormally during the constant current charging process and then determine whether the battery behaves abnormally during the constant voltage charging process, depending on the charging time of the battery, based on the measurement information received from the measurement unit 110.

[0058] Hereinafter, an embodiment in which the control unit 120 determines abnormal behavior of the battery during a constant current charging process will be described.

[0059] The control unit 120 may be configured to calculate a voltage change rate over time for each of the battery voltages measured by the measurement unit 110 during the constant current charging process.

[0060] Here, the rate of change of voltage may be the instantaneous rate of change of voltage over time. For example, if voltage is written as V and time is written as t, then the rate of change of voltage may be written as dV / dt.

[0061] The control unit 120 may be configured to determine that anomalous behavior has been confirmed if the calculated voltage change rate is less than a reference voltage change rate.

[0062] 3 is a diagram illustrating a charging process of a first battery according to an embodiment of the present invention, where the first battery may be a battery having lithium metal deposited on the surface of the negative electrode.

[0063] In the embodiment of Figure 3, the first battery may be charged with a constant current from time 0 to time t5, and then be charged with a constant voltage after time t5. At time t2, the battery voltage may increase to Va, and at time t3, the battery voltage may decrease to Vb. After time t3, the battery voltage may increase again and reach a reference value at time t5. That is, a constant current charging process may be performed from time 0 to time t5, and a constant voltage charging process may be performed after time t5.

[0064] 2, during a normal constant current charging process of a battery, the charging current remains unchanged and the voltage continues to increase. That is, during a normal constant current charging process of a battery, the voltage change rate may always be greater than or equal to the reference voltage change rate. For example, the reference voltage change rate may be 0 (V / s).

[0065] 3, the first battery may have a period during which the voltage change rate is less than the reference voltage change rate during constant current charging. The voltage change rate may be less than the reference voltage change rate between times t2 and t4. That is, the control unit 120 may be configured to determine that abnormal behavior has been confirmed when at least one of the voltage change rates calculated for each of the battery voltages is a negative number.

[0066] 3, if a section in which the voltage change rate is less than the reference voltage change rate appears during the constant current charging process, the first battery is not in a normal state, and the control unit 120 may check for abnormal behavior of the first battery based on the voltage change rate during the constant current charging process. If abnormal behavior of the first battery is confirmed, the control unit 120 may determine that lithium metal has precipitated in the first battery and may shut off charging and discharging of the first battery.

[0067] More specifically, the control unit 120 may be configured to calculate a temperature change rate over time for each of the battery temperatures measured by the measurement unit 110 during the constant current charging process.

[0068] Here, the temperature change rate may be the instantaneous rate of change of temperature over time. For example, if temperature is denoted as T and time is denoted as t, the temperature change rate may be written as dT / dt.

[0069] The control unit 120 may be configured to determine that abnormal behavior has been confirmed if the calculated temperature change rate is equal to or greater than a reference temperature change rate within a predetermined period of time and the voltage change rate is less than a reference voltage change rate.

[0070] The battery voltage measured by the measuring unit 110 may be the terminal voltage of the battery. The terminal voltage may be calculated based on Ohm's law (V = IR, where V is voltage, I is current, and R is resistance). If the temperature change rate of the battery is equal to or greater than a reference temperature change rate for a predetermined period of time, the internal resistance of the battery may decrease due to the influence of high temperature. That is, considering Ohm's law (V = IR), since the charging current is constant during a constant current charging process, if the internal resistance of the battery decreases, the battery voltage measured by the measuring unit 110 may decrease.

[0071] In the embodiment of FIG. 3, it is assumed that the period from t2 to t4 is equal to or greater than a predetermined period, and that the temperature change rate during the period from t2 to t4 is equal to or greater than a reference temperature change rate. For example, the reference temperature change rate is a temperature change rate of 1°C per minute, which can be expressed as 1 (°C / min). Between t2 and t4, the temperature of the first battery may rise to or exceed the reference temperature change rate. A sudden rise in the temperature of the first battery may reduce the internal resistance of the first battery, and this reduction in the internal resistance of the first battery may reduce the voltage of the first battery. That is, during the constant current charging process, a sudden rise in the temperature of the first battery may result in a section in which the voltage change rate of the first battery is less than the reference voltage change rate.

[0072] Therefore, the control unit 120 may determine abnormal behavior of the battery by taking into account both the temperature change rate and the voltage change rate of the battery. If abnormal behavior of the battery is confirmed, the control unit 120 may infer that lithium metal has precipitated in the battery.

[0073] The battery state estimating device 100 according to an embodiment of the present invention has an advantage in that it can quickly estimate whether or not lithium deposition has occurred in a battery based on measurement information acquired during the charging process of the battery. Therefore, the battery state estimating device 100 can quickly halt the operation of a battery in which lithium deposition has occurred, thereby preventing unexpected accidents such as fires and explosions.

[0074] Hereinafter, an embodiment will be described in which the control unit 120 determines abnormal behavior of the battery during a constant voltage charging process.

[0075] The control unit 120 may be configured to calculate a current change rate over time for each of the charging currents measured by the measurement unit 110 during the constant voltage charging process.

[0076] Here, the rate of change of current may be the instantaneous rate of change of charging current over time. For example, if charging current is denoted as I and time is denoted as t, the rate of change of current may be written as dI / dt.

[0077] The control unit 120 may be configured to determine that anomalous behavior has been confirmed if the calculated current change rate exceeds a reference current change rate.

[0078] 4 is a diagram illustrating a charging process of a second battery according to an embodiment of the present invention, where the second battery may be a battery having lithium metal deposited on the surface of the negative electrode.

[0079] In the embodiment of FIG. 4, the second battery may be charged with a constant current between 0 and t6, and then with a constant voltage after t6. Between 0 and t6, the charging current may be held constant, and the voltage of the second battery may increase. At t6, the voltage of the second battery may reach a reference value, and after t6, the voltage of the second battery may be held constant. Between t6 and t8, the charging current may decrease to Ia. Then, starting at t8, the charging current may increase, and at t9, the charging current may increase to Ib. After t9, the charging current may decrease again.

[0080] Referring to Figure 2, during a normal constant voltage charging process of a battery, the battery voltage remains unchanged and the charging current may continue to decrease. When the charging current reaches a cutoff value, the battery charging may be terminated. That is, during a normal constant voltage charging process of a battery, the current change rate may always be greater than or equal to the reference current change rate. For example, the reference current change rate may be 0 (mA / s).

[0081] 4, the second battery may experience a period in which the rate of change in charging current exceeds the reference rate of change in charging current during a constant voltage charging process. The rate of change in current may exceed the reference rate of change in charging current between times t8 and t9. That is, the control unit 120 may be configured to determine that abnormal behavior has been confirmed if at least one of the current change rates calculated for each charging current is a positive number.

[0082] 4, if a section in which the current change rate exceeds the reference current change rate appears during the constant voltage charging process, the second battery is not in a normal state, and the control unit 120 may determine whether the second battery is behaving abnormally based on the current change rate during the constant voltage charging process. If the control unit 120 determines that the second battery is behaving abnormally, it may determine that lithium metal has precipitated in the second battery and shut off charging and discharging of the second battery.

[0083] More specifically, the controller 120 may determine abnormal battery behavior by further considering the temperature change rate during the constant voltage charging process. Here, the temperature change rate has been described above, so a redundant description thereof will be omitted.

[0084] The control unit 120 may be configured to calculate a temperature change rate over time for each battery temperature measured by the measurement unit 110 during the constant voltage charging process. The control unit 120 may be configured to determine that abnormal behavior has been confirmed if the calculated temperature change rate is equal to or greater than a reference temperature change rate within a predetermined period of time and the current change rate exceeds a reference current change rate.

[0085] If the temperature change rate of the battery is equal to or greater than the reference temperature change rate for a predetermined period of time, the high temperature may cause the internal resistance of the battery to decrease. That is, considering Ohm's law (V=IR), the battery voltage is maintained constant during a constant voltage charging process, so if the internal resistance of the battery decreases, the charging current measured by the measuring unit 110 may increase.

[0086] In the embodiment of FIG. 4, it is assumed that the period from t7 to t10 is equal to or greater than a predetermined period, and that the temperature change rate during the period from t7 to t10 is equal to or greater than a reference temperature change rate. For example, the reference temperature change rate is a temperature change rate of 1°C per minute, which can be expressed as 1 (°C / min). Between t7 and t10, the temperature of the second battery may rise above the reference temperature change rate. A sudden rise in the temperature of the second battery may reduce the internal resistance of the second battery, and this decrease in the internal resistance of the second battery may reduce the charging current. That is, during the constant-voltage charging process, a sudden rise in the temperature of the second battery may result in a section in which the current change rate exceeds the reference current change rate.

[0087] Therefore, the control unit 120 may determine abnormal behavior of the battery by taking into account both the temperature change rate and the current change rate of the battery. If abnormal behavior of the battery is confirmed, the control unit 120 may infer that lithium metal has been deposited in the battery.

[0088] The battery state estimating device 100 according to an embodiment of the present invention has an advantage in that it can quickly estimate whether or not lithium deposition has occurred in a battery based on measurement information acquired during the charging process of the battery. Therefore, the battery state estimating device 100 can quickly halt the operation of a battery in which lithium deposition has occurred, thereby preventing unexpected accidents such as fires and explosions.

[0089] The battery state estimation 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 battery state estimation device 100 described above. In such a configuration, at least some of the components of the battery state estimation device 100 may be realized by complementing or adding functions to components included in a conventional BMS. For example, the measurement unit 110, the control unit 120, and the storage unit 130 of the battery state estimation device 100 may be realized as components of the BMS.

[0090] The battery state estimating device 100 according to the present invention may be installed in a battery pack. That is, the battery pack according to the present invention may include the above-described battery state estimating device 100 and one or more battery cells. The battery pack may further include electrical components (relays, fuses, etc.), a case, etc.

[0091] FIG. 5 is a diagram schematically illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention.

[0092] The positive terminal of the battery 10 may be connected to the positive terminal P+ of the battery pack 1, and the negative terminal of the battery 10 may be connected to the negative terminal P- of the battery pack 1.

[0093] The measurement unit 110 may be connected to a first sensing line SL1 and a second sensing line SL2. Specifically, the measurement unit 110 may be connected to a positive terminal of the battery 10 via the first sensing line SL1 and to a negative terminal of the battery 10 via the second sensing line SL2. The measurement unit 110 may measure the voltage of the battery 10 based on the voltages measured on the first sensing line SL1 and the second sensing line SL2.

[0094] The measurement unit 110 may be connected to the current measurement unit A via a third sensing line SL3. For example, the current measurement unit A may be an ammeter and / or a shunt resistor capable of measuring the charge current and discharge current of the battery 10. The measurement unit 110 may be connected to the current measurement unit A disposed in the charge / discharge path (large current path) of the battery B via the third sensing line SL3 to measure the charge / discharge current of the battery B. The measurement unit 110 may measure the charge current of the battery 10 via the third sensing line SL3. The measurement unit 110 may also calculate the discharge current of the battery 10 via the third sensing line SL3.

[0095] In addition, the measurement unit 110 can measure the temperature of the battery 10 through the fourth sensing line SL4.

[0096] Preferably, the measuring unit 110 can measure the voltage, current, and temperature of the battery 10 at the same period.

[0097] One end of the charging / discharging device 2 can be connected to the positive terminal P+ of the battery pack 1, and the other end can be connected to the negative terminal P- of the battery pack 1. Therefore, the positive terminal of the battery 10, the positive terminal P+ of the battery pack 1, the charging / discharging device 2, the negative terminal P- of the battery pack 1, and the negative terminal of the battery 10 can be electrically connected.

[0098] For example, the charging / discharging device 2 may be electrically connected to the positive terminal P+ and the negative terminal P− of the battery pack 1 to charge and / or discharge the battery 10 .

[0099] FIG. 6 is a diagram illustrating a battery state estimation method according to yet another embodiment of the present invention.

[0100] Preferably, each step of the battery state estimation method can be performed by the battery state estimation device 100. In the following, for ease of explanation, content that overlaps with the above description will be omitted or explained briefly.

[0101] Referring to FIG. 6, the battery state estimation method may include a measurement step (S100), an abnormal behavior determination step (S200), and a lithium deposition determination step (S300).

[0102] The measuring step (S100) is a step of measuring the charging current, the voltage and the temperature of the battery during the constant current charging process and the constant voltage charging process of the battery, and can be performed by the measuring unit 110.

[0103] The abnormal behavior determination step (S200) is a step of determining whether or not the battery is behaving abnormally based on the behavior of at least one of the charging current, the battery voltage, and the battery temperature during at least one of the constant current charging process and the constant voltage charging process, and can be performed by the control unit 120.

[0104] The control unit 120 may determine whether or not the battery behaves abnormally during the constant current charging process and / or the constant voltage charging process.

[0105] Specifically, during a constant current charging process, the control unit 120 can determine abnormal battery behavior based on the battery voltage and battery temperature. During a constant voltage charging process, the control unit 120 can determine abnormal battery behavior based on the charging current and battery temperature. This is because the charging current is kept constant during a constant current charging process, and the battery voltage is kept constant during a constant voltage charging process.

[0106] The lithium deposition determination step (S300) is a step of determining whether or not lithium deposition has occurred in the battery based on the presence or absence of abnormal behavior of the battery determined in the abnormal behavior determination step (S200), and can be performed by the control unit 120.

[0107] If abnormal behavior of the battery is confirmed in the abnormal behavior determination step (S200), the control unit 120 may determine that lithium metal has been deposited in the battery. Then, the control unit 120 may shut off charging and discharging of the battery to suspend use of the battery. Therefore, use of the battery in which lithium metal has been deposited can be immediately and quickly suspended, thereby preventing unexpected accidents such as fires and explosions.

[0108] Furthermore, since the battery state estimation method can be directly applied to the battery charging process, it is possible to quickly determine whether or not lithium deposition has occurred in the battery based on measurement information during the charging process. Preferably, it is possible to determine whether or not lithium deposition has occurred in the battery during each charging process, which makes it possible to prevent accidents caused by batteries with lithium deposition.

[0109] The above-described embodiments of the present invention may be realized not only by the apparatus and method but also by a program that realizes the functions corresponding to the configurations of the embodiments of the present invention or a recording medium on which the program is recorded. Such realization can be easily achieved by a person skilled in the technical field to which the present invention pertains, based on the description of the above-described embodiments.

[0110] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited to these, 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 scope of equivalents of the claims.

[0111] Furthermore, the present invention described above is susceptible to various substitutions, modifications, and alterations by a person having ordinary knowledge in the technical field to which the present invention pertains, within the scope of the technical concept of the present invention. Therefore, the present invention is not limited to the above-described embodiments and the accompanying drawings, but may be configured by selectively combining all or part of each embodiment for various modifications. [Explanation of symbols]

[0112] 1 battery pack 2 Charge / discharge device 10 Battery 100 Battery state estimation device 110 Measuring section 120 control section 130 Storage section

Claims

1. a measuring unit configured to measure a charging current, a voltage and a temperature of the battery during a constant current charging process and a constant voltage charging process of the battery; a control unit configured to determine whether or not the battery is behaving abnormally based on the behavior of at least one of the charging current and the voltage of the battery and the behavior of the temperature of the battery during at least one of the constant current charging process and the constant voltage charging process, and to determine whether or not lithium deposition is occurring in the battery based on the determined abnormal behavior of the battery; Including, The control unit is configured to first determine whether or not the battery is behaving abnormally during the constant current charging process, and if no abnormal behavior of the battery is confirmed, to determine whether or not the battery is behaving abnormally during the constant voltage charging process.

2. The control unit 2. The battery state estimation device according to claim 1, wherein the device is configured to determine that lithium has been deposited in the battery when abnormal behavior of the battery is confirmed during either the constant current charging process or the constant voltage charging process.

3. The control unit 3. The battery state estimation device according to claim 2, wherein the device is configured to calculate a voltage change rate over time for each of the battery voltages measured by the measurement unit during the constant current charging process, and to determine that the abnormal behavior has been confirmed if the calculated voltage change rate is less than a reference voltage change rate.

4. The control unit 4. The battery state estimation device according to claim 3, wherein the device is configured to determine that the abnormal behavior has been confirmed when at least one of the voltage change rates calculated for each of the battery voltages during the constant current charging process is a negative number.

5. A measuring unit configured to measure a charging current, a voltage and a temperature of a battery during a constant current charging process and a constant voltage charging process of the battery; a control unit configured to determine whether or not the battery is behaving abnormally based on the behavior of at least one of the charging current and the voltage of the battery and the behavior of the temperature of the battery during at least one of the constant current charging process and the constant voltage charging process, and to determine whether or not lithium deposition is occurring in the battery based on the determined abnormal behavior of the battery; Including, the control unit is configured to determine that lithium has been deposited in the battery when abnormal behavior of the battery is confirmed in either the constant current charging process or the constant voltage charging process; the control unit is configured to calculate a voltage change rate over time for each of the voltages of the battery measured by the measurement unit during the constant current charging process, and determine that the abnormal behavior has been confirmed when the calculated voltage change rate is less than a reference voltage change rate; The control unit is configured to calculate a temperature change rate over time for each of the battery temperatures measured by the measurement unit during the constant current charging process, and to determine that the abnormal behavior has been confirmed if the calculated temperature change rate is equal to or greater than a reference temperature change rate within a predetermined period of time and the voltage change rate is less than a reference voltage change rate.

6. The control unit 3. The battery state estimation device according to claim 2, configured to calculate a current change rate over time for each of the battery currents measured by the measurement unit during the constant voltage charging process, and to determine that the abnormal behavior has been confirmed if the calculated current change rate exceeds a reference current change rate.

7. The control unit 7. The battery state estimation device according to claim 6, wherein the device is configured to determine that the abnormal behavior has been confirmed when at least one of the current change rates calculated for each of the battery currents during the constant voltage charging process is a positive number.

8. A measuring unit configured to measure a charging current, a voltage and a temperature of a battery during a constant current charging process and a constant voltage charging process of the battery; a control unit configured to determine whether or not the battery is behaving abnormally based on the behavior of at least one of the charging current and the voltage of the battery and the behavior of the temperature of the battery during at least one of the constant current charging process and the constant voltage charging process, and to determine whether or not lithium deposition is occurring in the battery based on the determined abnormal behavior of the battery; Including, the control unit is configured to determine that lithium has been deposited in the battery when abnormal behavior of the battery is confirmed in either the constant current charging process or the constant voltage charging process; the control unit is configured to calculate a current change rate over time for each of the battery currents measured by the measurement unit during the constant voltage charging process, and determine that the abnormal behavior has been confirmed when the calculated current change rate exceeds a reference current change rate; The control unit is configured to calculate a temperature change rate over time for each of the battery temperatures measured by the measurement unit during the constant voltage charging process, and to determine that the abnormal behavior has been confirmed if the calculated temperature change rate is equal to or greater than a reference temperature change rate within a predetermined period of time and the current change rate exceeds a reference current change rate.

9. The control unit The battery state estimating device according to claim 2 , configured to shut off charging and discharging of the battery when it is determined that the lithium has been deposited in the battery.

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

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