Battery soc estimation apparatus and method

Abstract

A battery SOC estimation device according to an embodiment of the disclosure includes a charging and discharging unit configured to receive a control signal including C-rate information and charge and discharge a battery at a C-rate included in the control signal, a measurement unit configured to measure a voltage of the battery during charging and discharging of the battery, and a control unit configured to transmit the control signal to the charging and discharging unit, change the C-rate included in the control signal whenever a voltage value measured by the measurement unit reaches a preset threshold value, and estimate an SOC of the battery based on a result of comparing the changed C-rate with a preset cutoff value.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2022-0011728, filed in Korea on January 26, 2022, the disclosure of which is incorporated herein by reference.

[0002] This invention relates to a battery SOC estimation apparatus and method, and more specifically, to a battery SOC estimation apparatus and method for estimating the SOC of a battery. Background Technology

[0003] Recently, there has been a surge in demand for portable electronic products such as laptops, cameras, and mobile phones, and there has been significant development in electric vehicles, energy storage batteries, robots, and satellites. Therefore, research is actively underway to develop high-performance batteries that allow for repeated charging and discharging.

[0004] Currently available batteries include nickel-cadmium (NiCd), nickel-metal hydride (NiMH), nickel-zinc (NiZn), and lithium-ion batteries. Among these, lithium-ion batteries have attracted considerable attention because they exhibit virtually no memory effect compared to nickel-based batteries, and also possess extremely low self-discharge rates and high energy density.

[0005] Typically, the state of charge (SOC) of a battery can be estimated using a current integration method that integrates the charging / discharging current, or by measuring the OCV (overall voltage value) considering the correspondence between SOC and OCV (overall voltage value). Alternatively, an EKF (Extended Kalman Filter) based on a battery model utilizing the battery's voltage behavior can also be used to estimate SOC.

[0006] Since OCV is a measurable value in the idle state, the current integration method is mainly used during charging and discharging. However, the current integration method has a drawback: the SOC estimation result is inaccurate when errors accumulate during current integration or when the initial SOC value is inaccurate. Summary of the Invention

[0007] Technical issues

[0008] This disclosure aims to provide a battery SOC estimation apparatus and method that can more accurately estimate the battery's SOC by changing the charge / discharge rate (C) and comparing the changed C rate with a cutoff value.

[0009] These and other objects and advantages of this disclosure will become apparent from the following detailed description and will become even more fully apparent from the exemplary embodiments of this disclosure. Furthermore, it will be readily understood that the objects and advantages of this disclosure can be achieved by the means shown in the appended claims and combinations thereof.

[0010] Technical solution

[0011] A battery SOC estimation apparatus according to one aspect of the present disclosure may include a charging and discharging unit configured to receive a control signal including C-rate information and to charge and discharge the battery at a C-rate included in the control signal; a measuring unit configured to measure the battery voltage during the charging and discharging process; and a control unit configured to transmit the control signal to the charging and discharging unit, change the C-rate included in the control signal whenever the voltage value measured by the measuring unit reaches a preset threshold, and estimate the battery SOC based on the result of comparing the changed C-rate with a preset cutoff value.

[0012] The control unit can be configured to reduce the C-rate by a preset C-rate change rate whenever the measured voltage value reaches a preset threshold.

[0013] The control unit can be configured to estimate the battery's SOC to a preset SOC when the changed C rate is equal to or less than the cutoff value.

[0014] The control unit can be configured to estimate the battery's SOC as 100% when the C-rate, which is changed while the battery is charging, becomes equal to or less than the cutoff value.

[0015] The control unit can be configured to estimate the battery's SOC as 0% when the C-rate changes while the battery is discharging and becomes equal to or less than the cutoff value.

[0016] When the changed C rate exceeds the cutoff value, the control unit can be configured to set the standard SOC of the battery at the initial change time when the C rate is initially changed, and estimate the SOC of the battery based on the standard SOC, the number of C rate changes after the initial change time, and the expected number of C rate changes until the charging and discharging of the battery is terminated during the charging and discharging process.

[0017] The control unit can be configured to estimate the battery's SOC based on Equation 1 below when the changed C rate exceeds the cutoff value.

[0018] [Equation 1]

[0019]

[0020] Here, B SOC It can be the estimated SOC of the battery, T SOC It can be the SOC value predetermined based on the battery's charging and discharging state, R SOC It is a standard SOC, where n can be the expected number of changes in the C rate, and m can be the number of changes in the C rate.

[0021] The control unit can be configured to calculate the expected number of changes in the C-rate based on the changed C-rate, the cutoff value, and a preset C-rate change rate.

[0022] The control unit can be configured to calculate the expected number of changes in the C rate based on Equation 2 below.

[0023] [Equation 2]

[0024]

[0025] Here, n can be the expected number of changes in the C rate, d can be the C rate change rate, x can be the cutoff value, and y can be the initial C rate value included in the control signal.

[0026] The measurement unit can be configured to further measure the battery current during charging and discharging.

[0027] The control unit can be configured to set a standard SOC by integrating the battery current measured by the measuring unit from the start time of charging and discharging to the initial change time.

[0028] The control unit can be configured to transmit a charge and discharge termination signal to the charging and discharging unit when the changed C rate is less than or equal to the cutoff value.

[0029] The control unit can be configured to transmit a control signal, including the changed C rate, to the charging and discharging unit when the changed C rate exceeds a cutoff value.

[0030] According to another aspect of this disclosure, a battery pack may include a battery SOC estimation device according to another aspect of this disclosure.

[0031] A battery SOC estimation method according to another aspect of this disclosure may include: a charging and discharging step, which receives a control signal including C-rate information and charges and discharges the battery at a C-rate included in the control signal; a voltage measurement step, which measures the battery voltage during the charging and discharging process; a C-rate changing step, which changes the C-rate included in the control signal whenever the voltage value measured in the voltage measurement step reaches a preset threshold; and an SOC estimation step, which estimates the battery SOC based on a comparison of the C-rate changed in the C-rate changing step with a preset cutoff value.

[0032] Beneficial effects

[0033] According to one aspect of this disclosure, by charging and discharging the battery while changing the C rate, the state of charge (SOC) of the battery can be estimated more accurately. Specifically, this disclosure has the advantage of accurately estimating the SOC of the battery even when the initial C rate and temperature are not limited to specific values.

[0034] The effects of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the appended claims other effects not mentioned herein. Attached Figure Description

[0035] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, serve to provide a further understanding of the technical features of the present disclosure; therefore, the present disclosure should not be construed as limited to the drawings.

[0036] Figure 1 This is a diagram schematically illustrating a battery SOC estimation device according to an embodiment of the present disclosure.

[0037] Figure 2 This is a diagram illustrating an embodiment of a battery SOC estimation apparatus that estimates the SOC of a battery according to an embodiment of the present disclosure.

[0038] Figure 3 This is a diagram schematically illustrating an exemplary configuration of a battery pack according to another embodiment of the present disclosure.

[0039] Figure 4 This is a diagram schematically illustrating a battery SOC estimation method according to yet another embodiment of the present disclosure. Detailed Implementation

[0040] It should be understood that the terms used in the specification and appended claims should not be construed as limited to their general or dictionary meanings, but rather as being interpreted based on their meanings and concepts corresponding to the technical aspects of this disclosure, while allowing the inventors to define the terms appropriately for the best interpretation.

[0041] Therefore, the description presented herein is merely a preferred example for illustrative purposes and is not intended to limit the scope of this disclosure. It should be understood that other equivalents and modifications may be made thereto without departing from the scope of this disclosure.

[0042] Furthermore, in describing this disclosure, detailed descriptions of known elements or functions are omitted where such descriptions would obscure the key subject matter of the disclosure.

[0043] Terms including ordinal numbers such as “first” and “second” can be used to distinguish one element from another among various elements, rather than to limit the element by the term.

[0044] Throughout this specification, when a section is referred to as “comprising” or “including” any element, it means that the section may also include other elements, without excluding other elements, unless otherwise specifically stated.

[0045] Furthermore, throughout the specification, when one part is referred to as "connected" to another part, it is not limited to the case where they are "directly connected," but also includes the case where they are "indirectly connected," in which another element is inserted between them.

[0046] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0047] Figure 1 This is a schematic diagram illustrating a battery SOC estimation device 100 according to an embodiment of the present disclosure.

[0048] refer to Figure 1 The battery SOC estimation device 100 according to embodiments of the present disclosure may include a charging and discharging unit 110, a measurement unit 120, and a control unit 130.

[0049] The charging and discharging unit 110 can be configured to receive a control signal including C-rate information (current rate information).

[0050] For example, the charging and discharging unit 110 can be communicatively connected to the control unit 130 via wired and / or wireless communication. Furthermore, the charging and discharging unit 110 can receive control signals, including C-rate information, from the control unit 130.

[0051] Specifically, the initial value of the C-rate information included in the control signal can be set directly by the control unit 130 according to the battery specifications or by user input.

[0052] The charging and discharging unit 110 can be configured to charge and discharge the battery at a rate C included in the control signal.

[0053] Here, a battery refers to a physically separable, independent single unit with negative and positive terminals. For example, a lithium-ion battery or a lithium polymer cell can be considered a battery. Alternatively, a battery can refer to a battery module in which multiple cells are connected in series and / or parallel. In the following text, for ease of description, a battery will be described as referring to a single, independent unit.

[0054] Specifically, the charging and discharging unit 110 can read the C-rate information included in the control signal and charge or discharge the battery at the corresponding C-rate.

[0055] For example, when the C rate is preset to 1C, the charging and discharging unit 110 can charge the battery at a 1C C rate or discharge the battery at a 1C C rate.

[0056] However, it should be noted that there are no particular limitations on the value of the C rate information that can be included in the control signal. That is, the value of the C rate information can be set to 0.05C or higher. Preferably, the value of the C rate information can be set to 0.05C or higher and 3C or lower.

[0057] The measurement unit 120 can be configured to measure the battery voltage during the charging and discharging process of the battery.

[0058] Specifically, the measuring unit 120 can be connected to the positive and negative terminals of the battery. Furthermore, the measuring unit 120 can measure the battery voltage by measuring the positive and negative terminal voltages and calculating the difference between them. That is, the measuring unit 120 can measure the battery's terminal voltage during charging and discharging.

[0059] The control unit 130 can be configured to transmit control signals to the charging and discharging unit 110. As described above, the control unit 130 can generate a control signal including C-rate information and transmit the generated control signal to the charging and discharging unit 110.

[0060] The control unit 130 can be configured to change the C rate included in the control signal whenever the voltage value measured by the measuring unit 120 reaches a preset threshold.

[0061] Here, a preset threshold can be set for each of the charging and discharging processes. Preferably, the preset threshold can be the voltage value at which constant voltage charging or constant voltage discharging begins.

[0062] Typically, the charging process can include a constant current (CC) charging process and a constant voltage (CV) charging process. For example, constant current charging can be performed until the battery voltage reaches 3.8V, and constant voltage charging can be performed after reaching 3.8V. In this case, the threshold can be preset to 3.8V, which is the voltage value at which constant voltage charging begins. Similarly, during the discharging process, the voltage value at which constant voltage discharging begins can be set as the threshold.

[0063] More specifically, the control unit 130 can be configured to reduce the C-rate by a preset C-rate change rate whenever the measured voltage value reaches a preset threshold.

[0064] For example, suppose that during the battery charging process, the threshold is set to 3.8V, the C rate change rate is 0.5, and the initial C rate is preset to 1C.

[0065] The charging and discharging unit 110 can receive a control signal from the control unit 130, including information about the C-rate (1C), and charge the battery at 1C. When the voltage value measured by the measuring unit 120 reaches 3.8V, the control unit 130 can reduce the value of the C-rate information included in the control information from 1C to 0.5C.

[0066] Additionally, the charging and discharging unit 110 can receive a control signal from the control unit 130 including information about the C-rate (0.5C) and reduce the battery's C-rate to 0.5C. In this case, the voltage value measured by the measuring unit 120 may decrease as the C-rate decreases from 1C to 0.5C.

[0067] Specifically, the battery voltage is calculated based on Ohm's law, and the voltage of the battery being measured can be reduced because the C rate corresponding to "I" in the formula "V=IR" decreases.

[0068] More specifically, in a typical constant voltage charging process, the charging current gradually decreases to maintain the battery voltage at a specific level. However, in this disclosure, the C rate changes rapidly according to the C rate change rate, thus reducing the voltage.

[0069] Subsequently, the battery is charged at a C rate of 0.5C, and when the battery voltage reaches 3.8V again, the control unit 130 can reduce the C rate information included in the control signal to 0.25C.

[0070] Figure 2 This is a diagram illustrating an embodiment in which a battery SOC estimation device 100 estimates the SOC of a battery according to an embodiment of the present disclosure.

[0071] exist Figure 2 In this embodiment, battery charging can begin at time point t0. Specifically, at time point t0, the control unit 130 can transmit a control signal to the charging and discharging unit 110. The charging and discharging unit 110 can read the C-rate information included in the control signal and begin charging the battery at the corresponding C-rate.

[0072] From time point t0 to time point t1, the battery can be charged at 1C.

[0073] At time t1, the battery voltage can reach the threshold (V). TH In this case, the control unit 130 can reduce the value of the C rate information included in the control signal based on the C rate change rate. For example, the control unit 130 can reduce the value of the C rate information included in the control signal from 1C to 0.5C.

[0074] From time point t1 to time point t2, the battery can be charged at 0.5C.

[0075] At time t2, the battery voltage can reach the threshold (V) again. TH For example, the control unit 130 can reduce the value of the C rate information included in the control signal from 0.5C to 0.25C.

[0076] From time point t2 to time point t3, the battery can be charged at 0.25C.

[0077] At time t3, the battery voltage can reach the threshold (V) again. TH For example, the control unit 130 can reduce the value of the C rate information included in the control signal from 0.25C to 0.125C.

[0078] From time point t3 to time point t4, the battery can be charged at 0.125C.

[0079] At time t4, the battery voltage can reach the threshold voltage again (V). TH For example, the control unit 130 can reduce the value of the C rate information included in the control signal from 0.125C to 0.0625C.

[0080] From time point t4 to time point t5, the battery can be charged at 0.0625C.

[0081] At time t5, the battery voltage can reach the threshold voltage again (V). TH For example, the control unit 130 can reduce the value of the C rate information included in the control signal from 0.0625C to 0.03125C.

[0082] In addition, battery charging can be terminated at time t5.

[0083] The control unit 130 can be configured to estimate the battery's state of charge (SOC) based on the result of comparing the changed C rate with a preset cutoff value.

[0084] Here, the cutoff value is a predetermined C-rate value, and can be a reference value used to terminate battery charging and discharging. For example, the cutoff value can be preset to 0.05C.

[0085] That is, whenever the battery voltage reaches a threshold (V) TH When the battery is in a certain state, the control unit 130 can change the C-rate value included in the control signal and compare the changed C-rate value with the cutoff value. Furthermore, the control unit 130 can estimate the battery's SOC based on the comparison result.

[0086] Specifically, when the changed C-rate is less than or equal to the cutoff value, the control unit 130 can estimate the battery's SOC as a preset SOC. Here, the case where the changed C-rate is less than or equal to the cutoff value can correspond to the condition for the termination of battery charging or discharging.

[0087] For example, when the rate of change of C while the battery is charging becomes equal to or less than the cutoff value, the control unit 130 can be configured to estimate the battery's SOC as 100%. Conversely, when the rate of change of C while the battery is discharging becomes equal to or less than the cutoff value, the control unit 130 can be configured to estimate the battery's SOC as 0%.

[0088] As in the previous embodiments, in Figure 2 In this embodiment, assuming the battery begins charging at 1C at time point t0, the cutoff value can be preset to 0.05C. At times t1, t2, t3, t4, and t5, the battery voltage reaches the threshold value (V). TH At time t5, the control unit 130 can change the C rate to 0.03125C. Since the changed C rate (0.03125C) is equal to or less than the cutoff value (0.05C), the control unit 130 can estimate the battery's SOC to be 100% at time t5.

[0089] The current integration method commonly used for SOC estimation has the disadvantage of inaccurate SOC estimation results when errors accumulate during current integration or when the initial SOC value is inaccurate.

[0090] Therefore, in this disclosure, the SOC of a battery can be estimated by considering the characteristics of batteries with the same final charge or discharge amount under the same cutoff conditions. Consequently, the SOC estimation error based on the current integration method is corrected, making it possible to accurately estimate the battery's SOC.

[0091] Here, the battery characteristics considered in this disclosure are such that even if the battery's charging and discharging rates (C) and temperatures differ, charging and discharging can be performed in a uniform amount under the same cutoff conditions. For example, when a predetermined cutoff value (e.g., 0.05C) is applied as described in this disclosure, the final charge or discharge amount can be the same even if the battery's initial C rate and temperature differ.

[0092] Therefore, this disclosure has the advantage of accurately estimating the SOC of a battery based on the result of comparing the changed C rate with the cutoff value.

[0093] Meanwhile, the control unit 130 included in the battery SOC estimation device 100 may optionally include application-specific integrated circuits (ASICs), another chipset, logic circuits, registers, communication modems, and data processing devices, etc., known in the art, to execute the various control logics disclosed below. Furthermore, when the control logic is implemented as software, the control unit 130 can be implemented as a collection of program modules. In this case, the program modules can be stored in memory and executed by the control unit 130. The memory can be internal or external to the control unit 130 and can be connected to the control unit 130 by various known methods.

[0094] Additionally, the battery SOC estimation device 100 may also include a storage unit 140. The storage unit 140 may store data required for the operation and function of each component of the battery SOC estimation device 100, data generated during the execution of operations or functions, etc. The storage unit 140 is not particularly limited in its type, as long as it is a known information storage device capable of recording, erasing, updating, and retrieving data. As examples, the information storage device may include RAM, flash memory, ROM, EEPROM, registers, etc. Furthermore, the storage unit 140 may store program code defining processes that can be executed by the control unit 130.

[0095] The control unit 130 can be configured to transmit a control signal, including the changed C-rate, to the charging and discharging unit 110 when the changed C-rate exceeds a cutoff value. Conversely, the control unit 130 can be configured to transmit a charging and discharging termination signal, used to terminate the charging and discharging of the battery, to the charging and discharging unit 110 when the changed C-rate is less than or equal to the cutoff value.

[0096] Specifically, when the changed C rate exceeds the cutoff value, the control unit 130 can be configured to set the standard SOC of the battery at the initial change time when the C rate is initially changed.

[0097] Here, the initial change time can be the time when the battery voltage initially reaches a threshold (V) during charging and discharging. TH (The point in time)

[0098] For example, in Figure 2 In this embodiment, the battery voltage reaches a threshold (V) at time point t1. TH Therefore, the control unit 130 can change the C rate. Thus, in Figure 2 In one embodiment, time point t1 can be the initial change time.

[0099] More specifically, a standard SOC at the initial change time can be set using a current integration method. For this purpose, the measurement unit 120 can be configured to further measure the battery current during charging and discharging. Additionally, the control unit 130 can be configured to set the standard SOC by integrating the battery current measured by the measurement unit 120 from the start time of charging and discharging to the initial change time.

[0100] For example, in Figure 2 In this embodiment, the measurement unit 120 can measure the charging current of the battery from time point t0, the start of charging, to time point t1. Furthermore, the battery can set a standard SOC of 95% at time point t1 by integrating the charging current from time point t0 to time point t1.

[0101] Additionally, the control unit 130 can be configured to estimate the battery's SOC based on a standard SOC, the number of times the C-rate changes after the initial change time, and the expected number of times the C-rate changes are expected until the battery's charging and discharging processes are terminated.

[0102] Specifically, the control unit 130 may estimate the SOC when charging and discharging are in progress (when the changed C rate is initialized to the cutoff value) by taking into account the ratio of the number of changes in the C rate to the expected number of changes and the standard SOC.

[0103] More specifically, the control unit 130 can be configured to estimate the battery's SOC based on Equation 1 below.

[0104] [Equation 1]

[0105]

[0106] Here, B SOC It can be the estimated SOC of the battery, T SOC It can be the SOC value predetermined based on the battery's charging and discharging state, R SOC It can be a standard SOC, n can be the expected number of changes in the C rate, and m can be the number of changes in the C rate.

[0107] For example, in Figure 2 In this embodiment, an embodiment in which the control unit 130 estimates the state of charge (SOC) of the battery at time point t3 will be described. The control unit 130 may change the C rate from 0.25C to 0.125C at time point t3. At time point t3, the number of times (m) the control unit 130 changes the C rate is two, excluding the initial change time (t1).

[0108] Furthermore, when the initial C-rate (1C) is changed to a preset C-rate change rate (0.5), the time point at which the changed C-rate becomes equal to or less than the cutoff value is time point t5. Therefore, excluding the initial change time (t1), the expected number of C-rate changes (n) is 4. Here, even if the charging and discharging of the battery does not terminate, the control unit 130 can calculate the expected number of changes using the initial C-rate and the change rate.

[0109] exist Figure 2 In this embodiment, since the battery is charging, a predetermined SOC value (T) is set. SOC The standard SOC(R) is set at 100% and at the initial change time (t1). SOC The value is 95%. Therefore, the control unit 130 can calculate "95 + {(100-95) ÷ 4 × 2}" according to Equation 1, and the SOC(B) at time point t3 will be 95%. SOC The estimate is 97.5%.

[0110] Therefore, the battery SOC estimation device 100 according to the embodiments of the present disclosure has the advantage of estimating the battery's SOC not only when the charging and discharging of the battery is terminated, but also when the charging and discharging are in progress.

[0111] Meanwhile, referring to Equation 1, at the time point when the changed rate of C becomes equal to or less than the cutoff value, the expected number of changes (n) and the number of changes (m) of the rate of C can be the same. If so, the estimated SOC(B) SOC ) will be equal to the predetermined SOC value (T) SOC Therefore, even according to Equation 1, when charging and discharging are terminated (when the changed C rate becomes less than or equal to the cutoff value), the control unit 130 can estimate the SOC of the battery to a predetermined SOC value.

[0112] Additionally, the control unit 130 can be configured to calculate the expected number of changes in the C-rate based on the changed C-rate, the cutoff value, and a preset C-rate change rate.

[0113] Specifically, the control unit 130 can be configured to calculate the expected number of changes in the C rate based on Equation 2 below.

[0114] [Equation 2]

[0115]

[0116] Here, n can be the expected number of changes in the C-rate, d can be the rate of change of the C-rate, x can be the cutoff value, and y can be the initial C-rate value included in the control signal. Additionally, in Equation 2, the floor function... Used to exclude the number of changes in the C rate at the initial change time.

[0117] For example, in Figure 2 In this embodiment, the rate of change of C (d) can be 0.5, the initial C rate value (y) included in the control signal can be 1C, and the cutoff value can be 0.05C. Therefore, the control unit 130 can calculate the formula... The expected number of changes (n) in the C-rate is calculated as four. The expected number of changes (n) in the C-rate calculated in this way can be applied to Equation 1 and used to estimate the SOC of the battery.

[0118] That is, when a predetermined cutoff value (e.g., 0.05C) is applied, taking into account the following characteristics of the battery: even if the initial rate and temperature of the battery are different, the final charge or discharge amount is the same, the battery SOC estimation device 100 according to the embodiments of this disclosure has the advantage of accurately estimating the battery SOC.

[0119] Furthermore, according to embodiments of this disclosure, since the SOC value calculated by the current integration method can be corrected by comparing the changed C rate with the cutoff value, it also has the advantage of accurately estimating the SOC value of LFP cells that show a flat portion (plateau) in the SOC-OCV curve.

[0120] The battery SOC estimation device 100 according to this disclosure can be applied to a battery management system (BMS). That is, the BMS according to this disclosure may include the battery SOC estimation device 100 described above. In this configuration, at least some components of the battery SOC estimation device 100 can be implemented by supplementing or adding the functionality of components included in a conventional BMS. For example, the charging and discharging unit 110, the measurement unit 120, the control unit 130, and the storage unit 140 of the battery SOC estimation device 100 can be implemented as components of the BMS.

[0121] Furthermore, the battery SOC estimation device 100 according to this disclosure can be provided to the battery pack 1. That is, the battery pack 1 according to this disclosure may include the aforementioned battery SOC estimation device 100 and one or more individual battery cells. In addition, the battery pack 1 may also include electrical components (relays, fuses, etc.) and a housing.

[0122] Figure 3 This is a diagram schematically illustrating an exemplary configuration of a battery pack 1 according to another embodiment of the present disclosure.

[0123] refer to Figure 3 The positive terminal of battery B can be connected to the positive terminal P+ of battery pack 1, and the negative terminal of battery B can be connected to the negative terminal P- of battery pack 1.

[0124] The measurement unit 120 can be connected between the positive terminal of battery B and the positive terminal P+ of battery pack 1 via the first sensing line SL1, and can be connected between the negative terminal of battery B and the negative terminal P- of battery pack 1 via the second sensing line SL2. Therefore, the measurement unit 120 can measure the voltage of battery B via the first sensing line SL1 and the second sensing line SL2.

[0125] Additionally, the measurement unit 120 can be connected via the third sensing line SL3 to a current measuring element A disposed on the charging and discharging path (high current path) of the battery B to measure the charging and discharging current of the battery B. Here, the current measuring element A can be a galvanometer and / or a shunt resistor.

[0126] One end of the charging and discharging unit 110 can be connected between the positive terminal of battery B and the positive terminal P+ of battery pack 1, while the other end can be connected between the negative terminal of battery B and the negative terminal P- of battery pack 1. Furthermore, the charging and discharging unit 110 can charge and discharge battery B based on the C-rate information included in the control signal received from the control unit 130.

[0127] Figure 4 This is a diagram schematically illustrating a battery SOC estimation method according to yet another embodiment of the present disclosure.

[0128] Preferably, each step of the battery SOC estimation method can be performed by the battery SOC estimation device 100. In the following text, for ease of explanation, it should be noted that content overlapping with the foregoing will be briefly described or omitted.

[0129] refer to Figure 4 The battery SOC estimation method may include charging and discharging steps (S100), voltage measurement steps (S200), C-rate changing steps (S300), and SOC estimation steps (S400).

[0130] The charging and discharging step (S100) is a step of receiving a control signal including C-rate information and charging and discharging the battery B at the C-rate included in the control signal, and can be performed by the charging and discharging unit 110.

[0131] For example, the charging and discharging unit 110 can receive a control signal including C-rate information from the control unit 130. Additionally, the charging and discharging unit 110 can read the C-rate information included in the control signal and discharge or de-discharge the battery B at the corresponding C-rate.

[0132] The voltage measurement step (S200) is a step of measuring the voltage of battery B during the charging and discharging process of battery B, and can be performed by the measurement unit 120.

[0133] The rate change step (S300) occurs whenever the voltage value measured in the voltage measurement step (S200) reaches a preset threshold (V). TH The step of changing the C rate can be performed by the control unit 130.

[0134] Specifically, the control unit 130 can be configured to respond whenever the measured voltage value reaches a preset threshold (V). TH When the C rate is changed, the C rate will be changed to the preset C rate change rate.

[0135] For example, whenever the measured voltage value reaches a preset threshold (V) TH When the control unit 130 is in this state, it can reduce the C rate at a rate of 0.5.

[0136] The SOC estimation step (S400) is a step to estimate the SOC of battery B based on the result of comparing the C rate changed in the C rate change step (S300) with a preset cutoff value, and can be executed by the control unit 130.

[0137] Specifically, when the changed C rate is less than or equal to the cutoff value, the control unit 130 can estimate the SOC of battery B as a preset SOC. Furthermore, the control unit 130 can be configured to transmit a charge and discharge termination signal to the charge and discharge unit 110 to terminate the charging and discharging of battery B.

[0138] Conversely, when the changed C rate exceeds the cutoff value, the control unit 130 can be configured to estimate the SOC of battery B based on Equations 1 and 2 above. Furthermore, the control unit 130 can be configured to transmit a control signal, including the changed C rate, to the charging and discharging unit 110.

[0139] The embodiments of this disclosure described above can be implemented not only by apparatus and methods, but also by a program that implements functions corresponding to the configuration of the embodiments of this disclosure, or a recording medium on which a program is recorded. Based on the above description of the embodiments, those skilled in the art can readily implement the program or recording medium.

[0140] This disclosure has been described in detail. However, it should be understood that while the detailed description and specific examples indicate preferred embodiments of this disclosure, they are given by way of example only, as various changes and modifications within the scope of this disclosure will be apparent to those skilled in the art based on the detailed description.

[0141] Furthermore, since those skilled in the art can substitute, modify, and change the above-described disclosure in various ways without departing from the technical concept of the disclosure, the disclosure is not limited to the above embodiments and drawings, and all or some embodiments can be selectively combined to achieve various modifications.

[0142] (Explanation of reference numerals in the attached diagram)

[0143] 1: Battery pack

[0144] 100: Battery SOC estimation device

[0145] 110: Charging and discharging unit

[0146] 120: Unit of measurement

[0147] 130: Control Unit

[0148] 140: Storage unit

Claims

1. A battery SOC estimation device, comprising: A charging and discharging unit, the charging and discharging unit being configured to receive a control signal including C-rate information and to charge and discharge the battery at a C-rate included in the control signal; A measuring unit configured to measure the voltage of the battery during charging and discharging; as well as A control unit is configured to transmit the control signal to the charging and discharging unit, change the C-rate included in the control signal whenever the voltage value measured by the measuring unit reaches a preset threshold, and estimate the SOC of the battery based on the result of comparing the changed C-rate with a preset cutoff value.

2. The battery SOC estimation device according to claim 1, in, The control unit is configured to reduce the C-rate by a preset C-rate change rate whenever the measured voltage value reaches the preset threshold.

3. The battery SOC estimation device according to claim 1, in, The control unit is configured to estimate the SOC of the battery to a preset SOC when the changed C rate is equal to or less than the cutoff value.

4. The battery SOC estimation device according to claim 3, in, The control unit is configured to: When the rate of change of C during battery charging becomes equal to or less than the cutoff value, the state of charge (SOC) of the battery is estimated to be 100%. When the rate of change of C becomes equal to or less than the cutoff value while the battery is discharging, the SOC of the battery is estimated to be 0%.

5. The battery SOC estimation device according to claim 1, in, When the changed C-rate exceeds the cutoff value, the control unit is configured to set a standard SOC of the battery at the initial change time when the C-rate is initially changed, and to estimate the SOC of the battery based on the standard SOC, the number of C-rate changes after the initial change time, and the expected number of C-rate changes until the charging and discharging of the battery is terminated during the charging and discharging process.

6. The battery SOC estimation device according to claim 5, in, The control unit is configured to estimate the SOC of the battery based on Equation 1 below when the changed C rate exceeds the cutoff value. [Equation 1] Among them, B SOC It is the estimated SOC, T of the battery. SOC The SOC value, R, is predetermined based on the battery's state of charge and discharge. SOC Where is the standard SOC, n is the expected number of changes to the C rate, and m is the number of changes to the C rate.

7. The battery SOC estimation device according to claim 5, in, The control unit is configured to calculate the expected number of changes in the C-rate based on the changed C-rate, the cutoff value, and a preset C-rate change rate.

8. The battery SOC estimation device according to claim 7, in, The control unit is configured to calculate the expected number of changes in the C rate based on Equation 2 below. [Equation 2] Where n is the expected number of changes in the C-rate, d is the C-rate change rate, x is the cutoff value, and y is the initial C-rate value included in the control signal.

9. The battery SOC estimation device according to claim 5, in, The measuring unit is configured to further measure the current of the battery during the charging and discharging processes, and The control unit is configured to set the standard SOC by integrating the current of the battery measured by the measuring unit from the start time of charging and discharging to the initial change time.

10. The battery SOC estimation device according to claim 1, in, The control unit is configured to transmit a charge and discharge termination signal to the charging and discharging unit when the changed C rate is less than or equal to the cutoff value, thereby terminating the charging and discharging of the battery. The control unit is configured to transmit a control signal, including the changed C rate, to the charging and discharging unit when the changed C rate exceeds the cutoff value.

11. A battery pack comprising a battery SOC estimation device according to any one of claims 1 to 10.

12. A battery SOC estimation method, comprising: The charging and discharging steps receive a control signal including C-rate information and charge and discharge the battery at a C-rate included in the control signal. A voltage measurement step, wherein the voltage of the battery is measured during the charging and discharging process of the battery; The C-rate changing step changes the C-rate included in the control signal whenever the voltage value measured in the voltage measurement step reaches a preset threshold. as well as The SOC estimation step estimates the SOC of the battery based on a comparison between the C-rate changed in the C-rate changing step and a preset cutoff value.

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