Battery control device and battery control method

Abstract

A battery control device and a battery control method are disclosed. The battery control device according to an embodiment of the present invention includes: a measurement unit that measures the voltage of a battery and outputs a voltage measurement value indicating the measured voltage; a memory that stores multi-stage charging protocol data including a first charging rate, a second charging rate used in another constant current charging procedure following a constant current charging procedure using the first charging rate, and a first reference SOC associated with the first charging rate; and a processor that identifies the SOC of the battery based on the voltage measurement value. The processor performs a temporary discharge procedure when the SOC of the battery reaches the first reference SOC during the constant current charging procedure using the first charging rate, determines an adjusted second charging rate different from the second charging rate based on discharge information of the temporary discharge procedure, and performs a constant current charging procedure using the adjusted second charging rate after the temporary discharge procedure is completed.

Description

Technical Field

[0001] The present invention relates to a battery control device and method. More specifically, during the execution of a multi-stage charging procedure in which the magnitude of the charging current changes at least once according to the state of charge (SOC) of the battery, by providing at least one temporary discharge period, the present invention relates to a device and method for controlling a charging procedure using a multi-stage charging protocol so as to suppress the precipitation of lithium while charging the battery with high efficiency.

[0002] This application claims priority based on Korean Patent Application Nos. 10-2022-0049483 filed on April 21, 2022 and 10-2023-0050321 filed on April 17, 2023, and all of the content disclosed in the specifications and drawings of the applications is incorporated into this application.

Background Art

[0003] In recent years, as the demand for portable electronic products such as notebook computers, video cameras, and mobile phones has rapidly increased, and the development of electric vehicles, energy storage batteries, robots, satellites, etc. has become full-fledged, research on high-performance secondary batteries that can be repeatedly charged and discharged has been actively conducted.

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary batteries, etc. Among them, lithium secondary batteries are attracting attention for their advantages of being able to charge and discharge freely because they hardly exhibit a memory effect compared to nickel-based secondary batteries, having a very low self-discharge rate, and a high energy density.

[0005] Although much research is being actively conducted on such batteries in terms of increasing capacity and density, it is also important to improve their lifespan and safety. For this purpose, it is necessary to suppress the decomposition reaction with the electrolyte on the electrode surface, and it is required to prevent overcharging and over-discharging.

[0006] In particular, it is necessary to prevent lithium plating, which is a phenomenon in which lithium is deposited on the surface of the negative electrode. When lithium is deposited on the surface of the negative electrode, it causes side reactions with the electrolyte and changes in the kinetic balance of the battery, leading to battery degradation. In addition, the deposition of lithium on the surface of the negative electrode increases the possibility of internal short circuit in the battery, causing risks such as ignition and explosion.

[0007] In the case of fast charging, lithium plating on the surface of the negative electrode of the battery is promoted compared to slow charging, so the charging efficiency and battery durability may decrease.

[0008] Therefore, it is necessary to develop a technology to minimize the deposition of lithium on the surface of the negative electrode during battery charging and improve the efficiency of fast charging.

Summary of the Invention

Problems to be Solved by the Invention

[0009] The present invention has been devised to solve the above problems. During the process of charging a battery according to a multi-stage charging protocol, by performing a temporary discharging procedure between two adjacent charging stages, it is possible to reduce the amount of lithium deposition or remove at least a part of the already deposited lithium. An object of the present invention is to provide a battery control device and its method.

[0010] Another object of the present invention is to provide a battery control device and its method that compensates for the decrease in the state of charge (SOC) caused by a temporary discharging procedure by adjusting the charging rate in a constant current charging procedure following the temporary discharging procedure.

[0011] Other objects and advantages of the present invention can be understood from the following description and will become more apparent from the embodiments of the present invention. Also, the objects and advantages of the present invention can be realized by the means and their combinations shown in the claims.

Means for Solving the Problem

[0012] A battery control device according to one aspect of the present invention includes a measurement unit configured to measure the voltage of a battery and output a voltage measurement value indicating the measured voltage; a first charging rate, a second charging rate used in another constant current charging procedure following a constant current charging procedure using the first charging rate, and a first reference SOC related to the first charging rate - the first reference SOC is a value preset to prevent lithium precipitation in the battery in the constant current charging procedure using the first charging rate - and a memory storing multi-stage charging protocol data including the above; and a processor for identifying the SOC of the battery based on the voltage measurement value received from the measurement unit. During the execution of the constant current charging procedure using the first charging rate, when the SOC of the battery reaches the first reference SOC, the processor may execute a temporary discharge procedure, determine an adjusted second charging rate different from the second charging rate based on the discharge information of the temporary discharge procedure, and after the end of the temporary discharge procedure, execute a constant current charging procedure using the adjusted second charging rate.

[0013] The processor may be configured to determine the adjusted second charging rate based on the amount of change in the SOC of the battery during the execution of the temporary discharge procedure included in the discharge information.

[0014] The processor may be configured to determine the adjusted second charging rate to be greater than the second charging rate in order to compensate for the amount of change in the SOC of the battery due to the temporary discharge procedure.

[0015] The memory may further store a second reference SOC related to the second charging rate - the second reference SOC is a value preset to prevent lithium precipitation in the battery in the constant current charging procedure using the second charging rate.

[0016] The processor may be configured to determine the adjusted second charging rate further based on the first reference SOC, the second reference SOC, and the second charging rate.

[0017] When the processor executes a constant current charging procedure using the first charging rate and immediately executes a constant current charging procedure using the second charging rate when the SOC of the battery reaches the first reference SOC during the execution of the constant current charging procedure using the first charging rate, the processor may be configured to calculate a reference time predicted to be required for the SOC of the battery to reach the second reference SOC from the first reference SOC.

[0018] The processor may be configured to determine the adjusted second charging rate so that the sum of (i) the duration of the temporary discharging procedure included in the discharge information and (ii) the time required for the SOC of the battery to reach the second reference SOC by a constant current charging procedure using the adjusted second charging rate immediately after the end of the temporary discharging procedure is the same as the reference time.

[0019] The processor may be configured to determine the duration of the temporary discharging procedure so as to have a continuous or discrete negative correlation with the degree of use of the battery.

[0020] The processor may be configured to determine the adjusted second charging rate to be proportional to the sum of the difference between the first reference SOC and the second reference SOC and the amount of SOC change due to the temporary discharging procedure, and inversely proportional to the difference between the reference time and the duration of the temporary discharging procedure included in the discharge information.

[0021] The processor may be configured to execute the temporary discharging procedure to discharge the battery at a constant current equal to or lower than the first charging rate.

[0022] The processor may be configured to determine the magnitude of the constant current for the temporary discharge procedure such that it has a continuous or discrete negative correlation with the degree of use of the battery.

[0023] The processor determines whether it is necessary to execute the temporary discharge procedure based on the degree of use of the battery. If it is determined that the temporary discharge procedure needs to be executed, when the state of charge (SOC) of the battery reaches the first reference SOC, the temporary discharge procedure is executed. If it is determined that there is no need to execute the temporary discharge procedure, when the SOC of the battery reaches the first reference SOC, a constant current charging procedure using the second charging rate is executed without executing the temporary discharge procedure.

[0024] A battery pack according to another aspect of the present invention may include the battery control device.

[0025] An electric vehicle according to still another aspect of the present invention may include the battery control device.

[0026] A battery control method according to another aspect of the present invention is a battery control method executed by a battery control device. During the execution of a constant current charging procedure using a first charging rate, when the state of charge (SOC) of the battery identified based on a voltage measurement value indicating the measured voltage of the battery reaches a first reference SOC related to the first charging rate - the first reference SOC is a value preset to prevent lithium precipitation in the battery in the constant current charging procedure using the first charging rate - a step of executing a temporary discharge procedure is performed. Based on the discharge information of the temporary discharge procedure, a step of determining an adjusted second charging rate different from a preset second charging rate is performed so as to be used for another constant current charging procedure following the constant current charging procedure using the first charging rate. After the end of the temporary discharge procedure, a step of executing a constant current charging procedure using the adjusted second charging rate is performed.

Advantages of the Invention

[0027] According to at least one embodiment of the present invention, by providing at least one temporary discharge procedure during the charging of a battery according to a multi-stage charging protocol, at least a part of the lithium deposited inside the battery can be removed, and as a result, the charging efficiency can be improved. At this time, the temporary discharge procedure can be performed between two adjacent charging stages.

[0028] Also, according to at least one embodiment of the present invention, by adjusting the charging rate in the constant current charging procedure following the temporary discharge procedure, the decrease in the state of charge (SOC) due to the temporary discharge procedure is compensated, and thereby, the lengthening of the entire charging time required due to the temporary discharge period can be suppressed.

[0029] Also, according to at least one embodiment of the present invention, by adjusting at least one of the magnitude of the discharge current and the duration of the temporary discharge procedure in the temporary discharge procedure according to the degree of use of the battery, the long life of the battery can be achieved.

[0030] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0031] The drawings attached to this specification are for the purpose of further understanding the technical idea of the present invention together with the detailed description of the present invention to be described later, and thus the present invention is not to be construed as being limited only to the matters described in the drawings.

Brief Description of the Drawings

[0032]

Figure 1

Figure 2

Figure 3a

Figure 3b

Figure 4a

Figure 4b

Figure 4c

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0033] The terms and words used in this specification and the claims are not to be construed as limited to the ordinary or dictionary meanings, but should be construed in accordance with the meaning and concept corresponding to the technical idea of the present invention in accordance with the principle that the inventor himself can appropriately define the concept of the terms in order to explain the invention in the best way.

[0034] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and there may be various equivalents and modifications that can replace them at the time of this application.

[0035] In addition, when explaining the present invention, if it is recognized that a specific description of the known technology related to the present invention may make the gist of the present invention unnecessarily ambiguous, the detailed description thereof will be omitted.

[0036] Terms including ordinal numbers such as first and second are used to distinguish any one of various components from other elements, and the components are not limited by these terms.

[0037] Throughout the specification, when a certain part states that a certain component "includes", this means that, unless otherwise specified, it does not exclude other components, but may further include other components.

[0038] Incidentally, throughout the specification, when a certain part is "connected (coupled)" to another part, this includes not only the case where it is "directly connected (coupled)", but also the case where it is "indirectly connected (coupled)" with other elements interposed therebetween.

[0039] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0040] FIG. 1 shows a battery control device according to an embodiment of the present invention.

[0041] Referring to FIG. 1, a battery control device 100 according to an embodiment of the present invention may include a measurement unit 110, a memory 120, and a processor 130.

[0042] The measurement unit 110 may measure at least one of the voltage and current of the battery.

[0043] The measurement unit 110 may be configured to measure the voltage applied across both ends of the battery during the charging or discharging process of the battery. In this specification, the battery may mean one physically separable independent cell having a negative terminal and a positive terminal, or a battery module in which two or more cells are connected in series, parallel, or series-parallel. As an example, a lithium-ion battery or a lithium polymer battery may be regarded as the battery. Hereinafter, for convenience of explanation, the battery will be described as meaning one independent cell. In various examples, the voltage of the battery measured by the measurement unit 110 may be at least one of the open circuit voltage (OCV) of the battery or the load voltage measured when a load is connected to the battery.

[0044] The measurement unit 110 can employ various voltage measurement techniques known at the time of filing of the present invention. For example, the measurement unit 110 may include a voltage sensor known at the time of filing of the present invention. In particular, when the battery control device 100 according to the present invention is applied to a battery pack, the voltage sensor already provided in the battery pack can also be used as the measurement unit 110 according to the present invention.

[0045] The measurement unit 110 may be configured to measure the current flowing through the battery during the charging or discharging process of the battery. In this case, the measurement unit 110 may measure the voltage applied across both ends of the shunt resistor when the current flows, and convert the measured voltage into a current using Ohm's law. Alternatively, the measurement unit 110 may include other known current sensors such as a Hall sensor, and the current sensor can also be used to measure the current.

[0046] Memory 120 can be configured to store programs necessary to perform a multi-stage charging procedure for the battery, including multi-stage charging protocol data. As described above, the multi-stage charging protocol is a charging procedure in which the magnitude of the constant current changes at least once in at least a part of the entire SOC range from the SOC representing the fully discharged state of the battery to the SOC representing the fully charged state. That is, the multi-stage charging protocol can refer to a charging procedure in which when at least a part of the entire SOC range is divided into two or more sub-SOC ranges (which can be called "stages"), the charging rate used for charging in each sub-SOC range is predetermined. Incidentally, the SOC indicating the fully discharged state is usually set to 0%, but can be preset to a value greater than 0% for the purpose of extending the battery life. Similarly, the SOC indicating the fully charged state is usually set to 100%, but can be preset to a value less than 100% for the purpose of extending the battery life.

[0047] The multi-stage charging protocol data includes a first charging rate, a second charging rate used in another constant current charging procedure following the constant current charging procedure using the first charging rate, and a first reference SOC related to the first charging rate. The first reference SOC is a value preset to prevent lithium precipitation on the negative electrode of the battery in the constant current charging procedure using the first charging rate.

[0048] Memory 120 can store at least one reference SOC. Here, the reference SOC can be the SOC at which lithium precipitation is predicted on the negative electrode of the battery when the battery is charged at a predetermined charging rate (current rate or C-rate). For example, when the multi-stage charging procedure is a sequential flow of three constant current charging procedures having different charging rates, the number of reference SOCs is two. That is, the number of reference SOCs already stored in memory 120 may be one less than the number of constant current charging procedures included in the multi-stage charging procedure.

[0049] The memory 120 can store information regarding the state of charge (SOC) of the battery in which lithium is deposited on the negative electrode of the battery based on the charging rate. When the battery is charged at a constant current, the SOC at which lithium deposition occurs on the negative electrode of the battery can vary according to the magnitude of the constant current, that is, the charging rate. For example, the higher the charging rate used for constant current charging, the lower the SOC at which lithium deposition can occur. Thus, for a battery designed to have the same characteristics as the battery to be controlled in advance, information regarding the charging rate and the SOC at which lithium is deposited according to the charging rate can be experimentally obtained in advance through the charging process. For example, in a three-electrode type lithium secondary battery including a negative electrode, a positive electrode, and a reference electrode, by separating the potential of only the negative electrode and experimenting on the presence or absence of lithium deposition while changing the charging rate, information regarding the SOC at which lithium is deposited can be obtained in advance. Each reference SOC stored in the memory 120 indicates the relationship between the charging rate and the lithium deposition SOC (reference SOC) obtained as described above. The memory 120 can store curve data and / or a look-up table indicating the relationship between the charging rate and the reference SOC.

[0050] For example, assume that a multi-stage charging procedure includes a constant current charging procedure using a first charging rate and a subsequent constant current charging procedure using a second charging rate. In this case, the memory 120 can store a first reference SOC. The first reference SOC is the end condition of the constant current charging procedure using the first charging rate, that is, the reference for switching the magnitude of the constant current used in the constant current charging procedure from the first charging rate to the second charging rate.

[0051] The first reference SOC can be a threshold (limit value) at which no lithium deposition occurs or the amount of lithium deposition is less than a certain amount during constant current charging using the first charging rate when the SOC of the battery is less than the first reference SOC. That is, when the SOC of the battery reaches the first reference SOC by constant current charging using the first charging rate, lithium deposition of the battery can start, or the amount of lithium deposition by constant current charging using the first charging rate can be equal to or more than a certain amount.

[0052] Suppose that the multi-stage charging procedure further includes a constant-current charging procedure at a third charging rate following the constant-current charging procedure at a second charging rate. In this case, the memory 120 may further store a second reference SOC. The second reference SOC serves as a reference for switching the magnitude of the constant current used in the constant-current charging procedure from the second charging rate to the third charging rate. The second reference SOC is a threshold (limit value) at which no lithium precipitation occurs on the negative electrode of the battery or the amount of lithium precipitation is less than a certain amount during the constant-current charging at the third charging rate after the constant-current charging at the second charging rate is completed.

[0053] The memory 120 can store data, programs necessary for each component of the battery control device 100 to operate and execute functions, or data generated during the execution of operations and functions. The memory 120 can exist inside or outside the processor 130 and can be connected to the processor 300 by various well-known means. The memory 120 can store at least one program, application, data, or instructions executed by the processor 130. There is no special restriction on the type of the memory 120 as long as it is a known information storage means capable of recording, erasing, updating, and reading data. As an example, the memory 120 can be realized as at least one of a flash memory type, a hard disk type, a solid state disk (SSD) type, a solid disk drive (SDD) type, a multimedia card micro type, a random access memory (RAM), a static RAM (SRAM), a read only memory (ROM), an electrically erasable programmable read only memory (EEPROM), and a programmable read only memory (PROM). However, the present invention is not necessarily limited to such specific forms of the memory 120. Also, the memory 120 can store program codes defining processes executable by the processor 130.

[0054] The processor 130 can receive the voltage measurement value of the battery from the measurement unit 110. For example, the processor 130 can receive the voltage value of the battery from the measurement unit 110 in real time or periodically at regular time intervals.

[0055] While the multi-stage charging procedure of the battery is being executed, the processor 130 may identify the current state of charge (latest SOC) of the battery based on the received voltage measurement value. That is, the processor 130 may monitor the SOC of the battery in real time at a predetermined time interval during the multi-stage charging procedure.

[0056] The processor 130 may identify the current SOC of the battery in various ways. For example, the memory 120 may further include first mapping information that maps the SOC corresponding to the voltage measurement value (e.g., OCV), and after receiving the voltage measurement value from the measurement unit 110, the processor 130 may access the memory 120 to read out the SOC corresponding to the received voltage measurement value. Alternatively, the memory 120 stores a mathematical formula (e.g., ampere counting, extended Kalman filter) for calculating the SOC of the battery based on at least one of the voltage measurement value and the current measurement value output by the measurement unit 110, and the processor 130 may calculate the SOC using the mathematical formula stored in the memory 120.

[0057] For example, the processor 130 may identify the open circuit voltage of the battery based on the voltage measurement value using an equivalent circuit model of the battery. Here, the memory 120 further includes second mapping information that maps the SOC corresponding to the open circuit voltage of the battery, and the processor 130 may access the memory 120 to read out the SOC corresponding to the open circuit voltage. In another example, the processor 130 may identify the current SOC of the battery using the extended Kalman filter stored in the memory 120. Here, the extended Kalman filter is an algorithm based on an equivalent circuit model or an electrochemistry reduced order model and is well known in the technical field to which the present invention belongs, so a detailed description is omitted.

[0058] Alternatively, the measurement unit 110 can also calculate the amount of change in SOC by integrating over time the measured value of the current applied while the battery is being charged, and identify the SOC of the battery by adding the calculated amount of change in SOC to the initial SOC.

[0059] In this way, the processor 130 can receive the voltage measurement value of the battery from the measurement unit 110, obtain the SOC corresponding to the received voltage measurement value, and identify the obtained SOC as the current SOC of the battery.

[0060] The processor 130 can be configured to execute a temporary discharge procedure of discharging the battery for a predetermined time when the SOC of the battery reaches the first reference SOC during constant current charging using the first charging rate. That is, there is a temporary discharge period between the constant current charging procedure using the first charging rate and the constant current charging procedure using the adjusted second charging rate described later. The processor 130 can identify the latest value of the SOC of the battery in real time or at regular time intervals while the battery is being charged at the first charging rate, and recognize that the battery has reached the first reference SOC. The processor 130 can obtain the first reference SOC stored in the memory 120 while the battery is being charged at the first charging rate, and compare the first reference SOC with the SOC of the battery in real time or at regular time intervals. When the processor 130 recognizes that the SOC of the battery corresponds to the first reference SOC, it can be configured to discharge the battery for a predetermined time. For example, when the SOC of the battery reaches 70% of the first reference SOC during the constant current charging process using the first charging rate, the processor 130 can be configured to discharge the battery for a certain time (for example, 6 seconds) with charging stopped. At this time, the battery can be discharged with a constant current having a predetermined magnitude.

[0061] After the battery is discharged for the predetermined time, the processor 130 can be configured to execute a constant current charging procedure using a second charging rate adjusted to be different from the original second charging rate.

[0062] FIG. 2 exemplarily shows the state in which lithium is deposited while the battery is being charged.

[0063] The processor 130 may be configured to charge the battery according to a multi-stage charging procedure. As described above, when the SOC of the battery reaches the first reference SOC during the execution of the constant current charging procedure using the first charging rate, lithium may be deposited on the surface of the negative electrode. Referring to the first exemplary diagram 210, it can be seen that when a battery deteriorated for various reasons reaches the first reference SOC during the constant current charging process using the first charging rate, some metallic lithium has already been deposited on the surface of the negative electrode of the battery.

[0064] The processor 130 may be configured to discharge the battery that has reached the first reference SOC by the constant current charging procedure using the first charging rate for a predetermined time. Referring to the second exemplary diagram 220, it is shown that by temporarily discharging the battery between the constant current charging procedure using the first charging rate and the constant current charging procedure using the second charging rate adjusted thereto, the hysteresis accumulated by the charging current is eliminated by the reverse discharge current, and the lithium deposited on the surface of the negative electrode of the battery is removed. That is, by performing a temporary discharge procedure, it is possible to eliminate or at least delay the progress of lithium deposition that has become serious in the constant current charging procedure using the first charging rate. Thereby, compared with the conventional method of immediately starting the constant current charging procedure using the second charging rate after the end of the constant current charging procedure using the first charging rate, the charging efficiency and safety of the battery can be improved.

[0065] The discharge information of the temporary discharge procedure may be stored in the memory 120. Here, the discharge information includes at least one of the duration of the temporary discharge procedure, the magnitude of the constant current used for discharge, and the amount of SOC change due to discharge.

[0066] After the temporary discharge procedure associated with the second exemplary diagram 220 ends, the processor 130 may be configured to charge the battery at a second charging rate different from the first charging rate. For reference, the second charging rate (e.g., 1.5 °C) may be smaller than the first charging rate (e.g., 2.5 °C). The charging rate used for each constant current charging procedure included in the multi-stage charging procedure may be appropriately preset in advance based on various conditions such as the type and specifications of the battery, and the specifications of the device in which the battery is used.

[0067] Referring to the third exemplary diagram 230, it is shown that the amount of lithium deposited on the negative electrode at the start of the constant current charging procedure using the second charging rate has decreased compared to the amount shown in the first exemplary diagram 210.

[0068] After the end of the constant current charging using the first charging rate, the processor 130 charges the battery using a second charging rate smaller than the first charging rate, so that the amount of lithium precipitation generated during the execution of other charging procedures following the constant current charging procedure using the first charging rate is reduced, or the lithium precipitation rate is reduced.

[0069] According to the above components of the present invention, at least a part of the deposited lithium can be removed during charging of the battery. The processor 130 can not only discharge the battery for a predetermined time during the operation of charging the battery to relax the hysteresis due to the charging current, but also remove at least a part of the already deposited lithium, so that the charging amount of the battery can be predicted more accurately and easily.

[0070] Processor 130 is operatively connected to other components of the battery control device 100 and can control various operations of the battery control device 100. Processor 130 can execute various operations of the battery control device 100 by executing one or more instructions stored in memory 120. Processor 130 can selectively include processors, application-specific integrated circuits (ASICs), chip sets, logic circuits, registers, communication modems, data processing devices, etc. known in the art to execute various control logics performed in the present invention. Also, when the control logic is implemented by software, processor 130 can be implemented by a set of program modules. At this time, the program modules are stored in memory 120 and can be executed by processor 130.

[0071] In particular, when the battery control device 100 is realized in a form included in a battery pack, the battery pack may include a control device called by terms such as a microcontroller unit (MCU) or a battery management system (BMS). At this time, processor 130 can be realized by components such as an MCU or a BMS provided in such a general battery pack.

[0072] In this specification, terms such as "to do" or "configured to do" regarding the operations and functions of processor 130 may include the meaning of "programmed to do".

[0073] According to one embodiment, unlike the first charging rate used for constant current charging in the SOC range below the first reference SOC from the fully discharged state, a second charging rate adjusted instead of the second charging rate may be used for constant current charging in the SOC range above the first reference SOC. The processor 130 may determine an adjusted second charging rate used for a constant current charging procedure that starts on condition of the end of a temporary discharge procedure based on the amount of change (decrease) in the SOC value of the battery due to a temporary discharge performed since the SOC of the battery reached the first reference SOC. This will be described in detail with reference to FIGS. 3a and 3b.

[0074] FIG. 3a is a graph showing the voltage of the negative electrode according to the SOC in the process of charging the battery according to a multi-stage charging protocol. FIG. 3b is an enlarged view of the second section of FIG. 3a.

[0075] Referring to FIG. 3a, the X-axis value of the graph may indicate the SOC (%) (or SOC value (%)) of the battery, and the Y-axis value of the graph may indicate the voltage (or voltage value) of the negative electrode of the battery. Referring to FIG. 3, it can be seen that while the battery is being charged, the voltage of the negative electrode of the battery is gradually decreasing.

[0076] The first section P1 may correspond to a section in which the battery is charged at the first charging rate under the control of the processor 130. The second section P2 may correspond to a section in which the battery is discharged at a constant current having a fixed or determined magnitude by the processor 130 for at least a part of the time between the first section P1 and the third section P3 under the control of the processor 130. The third section P3 may correspond to a section in which the battery is charged at an adjusted second charging rate lower than the first charging rate under the control of the processor 130. In some embodiments, a predetermined rest time may be provided between the end point of the first section P1 and the start point of the second section P2 and / or between the end point of the second section P2 and the start point of the third section P3. The magnitude of the constant current in the temporary discharge procedure may be less than or equal to the first charging rate and greater than or equal to the magnitude of the adjusted second charging rate. For example, the first charging rate may be 1C, the adjusted second charging rate may be 0.8C, and the magnitude of the constant current in the temporary discharge procedure may be 0.9C, but these are examples and should not be construed in a limiting sense.

[0077] Referring to the first section P1, the processor 130 may obtain from the memory 120 a first reference SOC at which lithium precipitates when the battery is charged at the first charging rate, and may charge the battery to the first reference SOC at the first charging rate. For example, in the implementation graph of FIG. 3a, the first reference SOC may be 46%. The processor 130 may charge the battery at the first charging rate until the SOC of the battery reaches the first reference SOC from any SOC less than the first reference SOC.

[0078] Referring to the second section P2, when the processor 130 recognizes that the SOC of the battery corresponds to the first reference SOC, the processor 130 may stop the charging operation and discharge the battery for a predetermined time. In the second section P2, by discharging the battery for a predetermined time, at least a part of the lithium already deposited due to deterioration due to use or the constant current charging procedure using the first charging rate may be removed.

[0079] Referring to FIG. 3b, the state in which the SOC of the battery and the negative electrode voltage change as the battery discharges is shown. Here, in FIG. 3b, "delta SOC" may indicate the SOC (change amount of SOC) changed by the discharge in the second section P2. The processor 130 may discharge the battery at a constant current having the same magnitude as the first charging rate for a predetermined time in the second section P2. For example, when the first charging rate is 0.5C, the magnitude of the constant current used for the discharge in the second section P2 may also be 0.5C. In this way, when discharging the battery at a constant current having the same magnitude as the charging rate of the first section P1 in the second section P2, the processor 130 can easily calculate the change amount of the SOC in the second section P2. However, in various other embodiments, the processor 130 may discharge the battery at a value greater than the first charging rate in order to quickly alleviate the precursor symptoms of lithium precipitation deepened by the constant current charging procedure using the first charging rate in consideration of the deterioration of the battery.

[0080] The SOC of the battery decreases by the discharge procedure in the second section P2. Specifically, the change amount of the SOC of the battery in the second section P2 can be derived using the following Equation 1.

[0081] <Equation 1>

Number

[0082] In Equation 1, delta SOC (ΔSOC) is the change amount of the SOC when the battery is discharged at a predetermined constant current for t1. t1 means the time for discharging the battery (the predetermined time = the time length of the temporary discharge procedure).

[0083] The "60" in the denominator of Equation 1 is for converting the unit of t1 from minutes (used in the unit of t1) to hours according to Ah (Ampere-hour, related to the unit of the magnitude of the constant current a1 used in the discharging procedure), and the "100" is for expressing in %. Therefore, the "60" and "100" in Equation 1 should be understood as merely exemplary coefficients. For example, based on Equation 1, when the battery is discharged at a constant current of 2.5C for 5 seconds, it can be determined that deltaSOC = (5 / 60)×100 / 60×2.5 = a decrease of approximately 0.347%. For example, according to Equation 1, when the battery is discharged at a constant current of 2.5C for 5 seconds, it can be determined that delta SOC = (5 / 60)×100 / 60×2.5 = a decrease of approximately 0.347%.

[0084] Referring to the third interval P3 in FIG. 3a, after discharging the battery, the processor 130 may charge the battery at a second adjusted charge rate different from the first charge rate. At this time, the processor 130 may be configured to determine the adjusted second charge rate by adjusting the original second charge rate based on the change in the SOC value of the battery due to the temporary discharging procedure (the estimated value of the SOC decrease amount according to Equation 1). For example, the processor 130 may cause the SOC of the battery to be charged to the second reference SOC at the adjusted second charge rate during the third interval P3, while compensating for the SOC decreased due to the discharging of the battery.

[0085] More specifically, the processor 130 may be configured to identify the change amount of the SOC value after battery discharging and determine the adjusted second charge rate to compensate for the identified SOC change amount.

[0086] Processor 130 may control the charging process of the battery according to a preset charging schedule (charging sequence according to the multi-stage charging protocol). Processor 130 may charge the battery to correspond to a preset charging schedule while compensating for the amount of change in SOC due to discharge in the second section P2 of the battery. Hereinafter, an embodiment will be described in which Processor 130 determines the adjusted second charging rate so that the amount of change in SOC during discharge is compensated when it has a preset charging schedule.

[0087] Processor 130 may determine an adjusted second charging rate to correspond to a preset charging time based on a preset charging schedule. For example, the time required until charging is completed may be preset according to a preset charging schedule. Processor 130 may determine an adjusted second charging rate so that the time required to charge up to the second reference SOC while allowing the time required for discharge is the same as the required time based on a preset charging schedule (without a temporary discharge procedure). Therefore, Processor 130 can mitigate the lithium deposition phenomenon (remove at least a part of lithium) by discharging the battery for a predetermined time during charging of the battery without increasing the overall charging time, thereby improving the charging efficiency of the battery.

[0088] Charging the battery according to a preset charging schedule may mean charging the battery at a first charging rate until the SOC of the battery reaches a first reference SOC, and charging the battery at a second charging rate without a temporary discharge procedure until the SOC of the battery reaches from the first reference SOC to a second reference SOC.

[0089] The memory 120 may store a second reference SOC at which lithium is predicted to precipitate when charging at a second charging rate corresponding to a preset charging schedule. The memory 120 may store the second reference SOC together with a first reference SOC at which lithium is predicted to precipitate on the negative electrode of the battery when charging at a first charging rate corresponding to a preset charging schedule. The first reference SOC and the second reference SOC may be stored in the memory 120 in a pre-stored state, and the processor 130 may access the memory 120 to obtain the first reference SOC and the second reference SOC.

[0090] As a more specific example, the processor 130 may have a preset charging schedule in which when the battery is charged at 2.5C and the SOC of the battery reaches 46%, the charging rate is immediately changed to charge at 1.5C until the SOC of the battery reaches 62.1%. At this time, 2.5C may correspond to the first charging rate, 46% may correspond to the first reference SOC, 1.5C may correspond to the second charging rate, and 62.1% may correspond to the second reference SOC.

[0091] The processor may be configured to identify the second reference SOC and calculate a reference time predicted to be required for the SOC of the battery to reach from the first reference SOC to the second reference SOC when charging the battery at the second charging rate. According to the preset charging schedule, the processor 130 may derive the time required to charge the battery at a specific charging rate (such as the second charging rate) based on the information regarding the reference SOC obtained from the memory 120 using the following Equation 2.

[0092] <Equation 2>

Number

[0093] In Equation 2, b1 represents the charging rate, and c1 represents the change in SOC. t2 derived from Equation 2 represents the time required for the SOC of the battery to increase by c1 when charging the battery at the charging rate of b1.

[0094] In Equation 2, the unit of t2 is exemplified as minute. That is, according to Equation 2, when the processor 130 charges the battery at the second charging rate of 1.5C immediately after the SOC of the battery reaches 46% which is the first reference SOC based on a preset charging schedule, it can be predicted that it takes about 6.44 minutes until the battery reaches 62.1% which is the second reference SOC. Here, the calculated 6.64 minutes can be used as the reference time.

[0095] The processor 130 may determine the adjusted second charging rate such that the remaining charging time required for the SOC of the battery (less than the first reference SOC) at the end of the temporary discharge procedure in the second interval P2 to reach the second reference SOC corresponds (matches) to the reference time. That is, the processor 130 ensures that the sum of the time length of the temporary discharge procedure performed at the end of the constant current charging procedure using the first charging rate and the required time of the constant current charging procedure using the adjusted second charging rate is not longer than the time required for starting the constant current charging procedure using the original second charging rate immediately without discharging from the end point of the constant current charging procedure using the first charging rate (SOC of the battery = first reference SOC) until the SOC of the battery reaches the second reference SOC, and may determine the adjusted second charging rate accordingly.

[0096] The processor 130 may be configured to determine the adjusted second charging rate to correspond (match) to the reference time based on (i) the difference between the first reference SOC and the second reference SOC, (ii) the change in SOC during the second interval P2, and (iii) the time length of the temporary discharge procedure. That is, the adjusted second charging rate may be proportional to the sum of the difference between the first reference SOC and the second reference SOC and the change in SOC due to discharge, and inversely proportional to the difference between the reference time and the predetermined time.

[0097] Specifically, when the processor 130 charges the battery at the second charging rate based on a preset charging schedule (without a temporary discharge period), it is necessary to charge the battery by 16.1% for 6.44 minutes.

[0098] When the processor 130 charges the battery in the order of executing a temporary discharge procedure after the constant current charging procedure using the first charging rate and then executing the constant current charging procedure again, the duration of the temporary discharge procedure (for example, 5 seconds = approximately 0.083 minutes) and the SOC value decreased by the temporary discharge procedure (for example, approximately 0.347%) are compensated, and the adjusted second charging rate can be determined. That is, the processor 130 can determine the adjusted second charging rate, which is a constant current value large enough to charge the battery by 16.447% (16.1% + 0.347%) in about 6.357 minutes (6.44 minutes - 0.083 minutes) to compensate for the decreased SOC in the second interval P2. For example, the processor 130 can determine the adjusted second charging rate to be approximately 1.552C using Equation 2.

[0099] Therefore, according to the present invention, even if a temporary discharge interval according to the second interval P2 is added after the constant current charging procedure with the first charging rate is completed, there is an advantage that the overall charging time from the time when the SOC of the battery reaches the first reference SOC to the time when it reaches the second reference SOC can be maintained at substantially the same level.

[0100] In particular, the processor 130 can be configured to determine the adjusted second charging rate so as to have a value smaller than the first charging rate and larger than the second charging rate.

[0101] In addition, although the embodiment in which the processor 130 changes the charging rate once in the multi-stage charging procedure has been exemplarily described, the number of times the processor 130 changes the charging rate is not to be construed as limited. As an example, the processor 130 may change the charging rate two or more times depending on the type of load using the battery. Specifically, when the battery control device 100 according to the present invention is applied to an electric vehicle, the processor 130 can also change the charging rate ten or more times by the method of compensating for the SOC change amount due to the aforementioned discharge.

[0102] In particular, when the battery repeatedly charges and discharges above a certain level, it may deteriorate and the amount of lithium deposited on the negative electrode may increase. Since the reference SOC stored in the memory 120 is data based on the battery in the initial state, when the reference SOC is applied to a deteriorated battery, the charging efficiency has to decrease compared to a new battery. For example, when the battery is deteriorated to a certain extent, even if constant current charging is performed at the first charging rate, lithium precipitation may already start at an SOC smaller than the first reference SOC. Therefore, if the charging schedule of the battery is set using the reference SOC based on the initial state (new state) of the battery, there may be an error in the amount of charge actually charged to the battery. According to an embodiment of the present invention, by performing a discharging operation during charging to remove lithium, the actual amount of charge of the battery can be accurately predicted.

[0103] In addition, when starting a temporary discharging procedure at an SOC smaller than the first reference SOC, since there is no lithium that has already been deposited or is at a negligible level in the constant current charging procedure using the first charging rate, the effect of improving the charging efficiency by the temporary discharging procedure may not be obtained. The processor 130 according to an embodiment can discharge the battery on the condition that the first reference SOC is reached, thereby removing the lithium deposited in the constant current charging procedure using the first charging rate as quickly as possible, and thereby improving the charging efficiency of the battery.

[0104] Figure 4a is a graph showing the voltage of the negative electrode according to the SOC in the process of charging a battery by a processor according to an embodiment of the present invention. Figure 4b is a graph showing dV / dQ of the negative electrode according to the SOC in the process of charging a battery by a processor according to an embodiment of the present invention. Figure 4c is an enlarged view of a specific region R1 in Figure 4b.

[0105] In the first graph of Figure 4a, the X-axis represents the SOC of the battery, and the Y-axis represents the negative electrode voltage of the battery. In the second graph of Figure 4b, the X-axis represents the SOC of the battery, and the Y-axis represents dV / dQ of the negative electrode of the battery.

[0106] Referring to the first graph of Figure 4a, the processor 130 can charge the battery until the SOC of the battery reaches 46% at a charging rate of 2.5C. When the processor 130 recognizes that the current SOC of the battery corresponds to 46%, the processor 130 can discharge the battery for the aforementioned predetermined time.

[0107] In particular, the processor 130 can discharge the battery at a constant current having the same value as the first charging rate for the predetermined time. Thereby, the processor 130 can easily calculate the amount of change in SOC due to the discharge for the predetermined time.

[0108] Referring to the first graph of Figure 4a, similar to Figure 3a, when the SOC of the battery reaches the first reference SOC and the battery is discharged for the predetermined time (for example, 5 seconds), the part where the voltage value of the negative electrode and the SOC of the battery change is shown. This has already been described with reference to Figures 3a and 3b, so duplicate explanations are omitted.

[0109] The processor 130 can compensate for the SOC value that changes according to the discharge time and determine a second charging rate adjusted to correspond to the charging time based on a preset charging schedule. The processor 130 can charge the battery at 1.552C immediately at the end of the temporary discharge procedure.

[0110] The second graph in FIG. 4b is a differential curve obtained by differentiating the curve of the first graph, that is, a graph obtained by differentiating the voltage of the negative electrode with respect to the SOC (or capacitance Q). The specific region R1 illustrates the dV / dQ of the negative electrode of the battery in the SOC range preset in the multi-stage charging protocol so that a constant current charging procedure using the adjusted second charging rate is performed. Referring to FIG. 4c which shows an enlarged view of the specific region R1 of the second graph, a critical point R2 corresponding to a point where the trend (slope) of the line diagram of the graph changes abruptly (for example, a minimum point, a maximum point) is plotted. The critical point R2 may correspond to a point where lithium is deposited on the negative electrode and the dV / dQ of the negative electrode changes abruptly.

[0111] The processor 130 may be configured to grasp such a critical point R2. At this time, the processor 130 may access the memory 120 to read relevant data, or execute relevant mathematical formulas and calculation processes, etc., in order to grasp such a critical point R2.

[0112] The processor 130 may recognize the dV / dQ of the negative electrode at regular time intervals while the battery is being charged. The processor 130 may identify the tendency of the dV / dQ value to change based on the recognized dV / dQ. The processor 130 may identify a point where the change amount of the dV / dQ is abrupt in the process of recognizing the dV / dQ of the negative electrode at regular time intervals. For example, the processor 130 may obtain information representing the dV / dQ at regular time intervals and calculate the change amount from the previous dV / dQ. The processor 130 may detect a specific point where the dV / dQ value decreases by a change amount equal to or greater than a threshold value from the previous dV / dQ value, and then the dV / dQ value increases by a change amount equal to or greater than the threshold value, as the critical point R2. The critical point R2 is related to the SOC at which the abrupt change of the aforementioned dV / dQ occurs due to the lithium deposited on the negative electrode.

[0113] Also, the inflection point R2 is the SOC at which lithium precipitates on the negative electrode of the battery while performing constant current charging at the adjusted second charging rate in order to compensate for the amount of SOC decrease due to the execution of the temporary discharge procedure after constant current charging using the first charging rate and a temporary discharge procedure. Lithium precipitation occurs when performing a constant current charging procedure using the second charging rate without the temporary discharge procedure, and it can be an SOC higher than a predetermined second reference SOC (for example, 62.1%). That is, at the end of the constant current charging procedure using the first charging rate, the processor 130 changes the multi-stage charging protocol to execute a temporary discharge procedure and a constant current charging procedure using the adjusted second charging rate instead of the constant current charging procedure using the second charging rate, so that lithium precipitation occurring during battery charging can be delayed, and the battery can be charged with high efficiency.

[0114] Also, the processor 130 can utilize various known battery state detection algorithms and the like to recognize the degree of battery usage (for example, the number of charge / discharge cycles, the capacity retention rate), and determine the length of time for discharging the battery based on the recognized degree of usage. For example, as the battery deteriorates due to repeated use of the battery, the amount of lithium precipitating on the negative electrode of the battery may increase. When the amount of precipitating lithium increases, it is necessary to increase the length of the time of the second section P2 during which the battery is discharged.

[0115] When the processor 130 recognizes that the degree of battery usage (e.g., the number of charge-discharge cycles, the degree of degradation) is greater than a threshold value, it may determine that the duration of the temporary discharge procedure is longer than the set time (e.g., 5 seconds), such as 6 seconds. Alternatively, when the processor 130 recognizes that the degree of battery usage is less than the threshold value, it may determine that the duration of the temporary discharge procedure is the same as or shorter than the set time (e.g., 5 seconds), such as 4 seconds. When the number of charge-discharge cycles of the battery exceeds the threshold value, the processor 130 may increase the discharge time of the battery to discharge for 6 seconds. When the number of charge-discharge cycles of the battery is below the threshold value, it may determine that the duration of the temporary discharge procedure is 5 seconds corresponding to the set time. The above numerical values are exemplary and should not be construed in a limiting sense.

[0116] According to such an implementation configuration of the present invention, while the battery is being charged, it discharges for a predetermined time and resumes charging at a charging rate that can compensate for the change in SOC due to the discharge, thereby completing the charging of the battery according to a preset charging schedule. Also, according to such an implementation configuration of the present invention, by removing the deposited lithium, the SOC of the battery can be predicted more accurately. Furthermore, by controlling the discharge time according to the degree of battery degradation, the charging efficiency and the accuracy of SOC prediction can be further improved.

[0117] The battery control device 100 according to the present invention can be applied to a battery pack. That is, the battery pack according to the present invention may include the battery control device 100 according to the present invention described above. Further, the battery pack according to the present invention may further include, in addition to the battery control device 100 according to the present invention, components usually included in a battery pack, for example, one or more batteries, a battery management system (BMS), a current sensor, a relay, a fuse, a pack case, and the like. In this case, the secondary battery included in the battery pack may be the object to be controlled by the battery control device 100 according to the present invention, that is, the target battery. Further, at least some components of the battery control device 100 according to the present invention may be realized by conventional components included in the battery pack. For example, the measurement unit 110 of the battery control device 100 according to the present invention may be realized by a voltage sensor included in the battery pack. Further, at least some functions and operations of the processor 130 of the battery control device 100 according to the present invention may be realized by the BMS included in the battery pack.

[0118] Further, the battery control device 100 according to the present invention can be applied to an electric vehicle. That is, the electric vehicle according to the present invention may include the battery control device 100 according to the present invention described above. In particular, in the case of an electric vehicle, since the battery pack is a very important component as a drive source, the battery control device 100 according to the present invention can be more usefully applied. Further, the electric vehicle according to the present invention may further include, in addition to such a battery control device 100, various other devices, for example, a vehicle body, vehicle control units such as an ECU, a motor, connection terminals, a DC-DC converter, and the like. In addition to this, it goes without saying that the electric vehicle according to the present invention can further adopt components usually included in an electric vehicle.

[0119] FIG. 5 is a flowchart schematically showing a battery control method according to another embodiment of the present invention. The method of FIG. 5 can be executed in response to the battery control device 100 receiving a message notifying the start of the battery charging procedure from an external charger or the like. In FIG. 5, the main body of each step can be each component of the battery control device 100 according to the present invention described above. For the sake of convenience of explanation, it is assumed that the SOC of the battery at the time when the method of FIG. 5 is started is less than the first reference SOC.

[0120] Referring to FIGS. 1 to 5, in step S510, the processor 130 executes a constant current charging procedure using the first charging rate. For example, the processor 130 may request the external charger to supply a charging current having a magnitude corresponding to the first charging rate.

[0121] In step S520, the processor 130 determines whether the SOC of the battery determined based on the voltage measurement value indicating the voltage of the battery received from the measurement unit 110 has reached the first reference SOC. The voltage measurement value of the battery can be measured periodically or at predetermined time intervals by the measurement unit 110 while the battery is being charged at the first charging rate.

[0122] The first reference SOC is a value preset to prevent lithium precipitation on the negative electrode of the battery when a constant current charging procedure using the first charging rate is performed on the battery. For example, the first reference SOC is an SOC value or a preset SOC value predicted to start lithium precipitation or the severity of lithium precipitation to reach a certain level at the negative electrode of the battery when constant current charging is continued at the first charging rate since the SOC of the battery is lower than the first reference SOC.

[0123] If the value of step S520 is "Yes (Yes)", the process proceeds to step S530. If the value of step S520 is "No (No)", the processor 130 returns to step S510 and continues the constant current charging procedure using the first charging rate.

[0124] In step S530, the processor 130 executes a temporary discharge procedure. That is, in step S530, the charging procedure switches from the constant current charging procedure using the first charging rate to the temporary discharge procedure. The temporary discharge procedure can be executed with a constant current of a predetermined magnitude for a predetermined time. That is, the battery is discharged between the constant current charging procedure using the first charging rate and the constant current charging procedure using the second charging rate. When the battery is discharged, at least a part of the lithium deposited on the negative electrode of the battery can be removed.

[0125] In step S540, the processor 130 executes a constant current charging procedure using the second charging rate. That is, in step S540, the charging procedure switches from the temporary discharge procedure to the constant current charging procedure using the second charging rate.

[0126] In step S550, the processor 130 determines whether the SOC of the battery has reached the second reference SOC. If the value of step S540 is "Yes", the method of FIG. 5 can end. If the value of step S550 is "No", the processor 130 returns to step S540 and continues the constant current charging procedure using the second charging rate.

[0127] Although FIG. 5 illustrates that the method ends when the SOC of the battery reaches the second reference SOC, this is only an example. If the multi-stage charge-discharge procedure includes three or more constant current charging procedures, additional constant current charging procedures or constant voltage charging procedures can be continuously executed.

[0128] FIG. 6 is a flowchart schematically showing a battery control method according to still another embodiment of the present invention. The method of FIG. 6 can be executed in response to the battery control device 100 receiving a message notifying the start of the charging procedure of the battery from an external charger or the like. In FIG. 6, the main body of each step can be each component of the battery control device 100 according to the present invention described above. For the sake of convenience of explanation, it is assumed that the SOC of the battery at the time when the method of FIG. 6 is started is less than the first reference SOC.

[0129] Referring to FIGS. 1 to 4 and FIG. 6, in step S610, the processor 130 executes a constant current charging procedure using the first charging rate.

[0130] In step S620, the processor 130 determines whether the SOC of the battery determined based on the voltage measurement value indicating the voltage of the battery received from the measurement unit 110 has reached the first reference SOC. The voltage measurement value of the battery can be measured periodically or at predetermined time intervals by the measurement unit 110 while the battery is being charged at the first charging rate.

[0131] The first reference SOC is a value preset to prevent lithium precipitation on the negative electrode of the battery when a constant current charging procedure using the first charging rate is performed on the battery. For example, the first reference SOC is the SOC value or the preset SOC value at which lithium precipitation begins to occur at the negative electrode of the battery or the severity of lithium precipitation is predicted to increase to a certain level when constant current charging is continued at the first charging rate from when the SOC of the battery is lower than the first reference SOC.

[0132] If the value of step S620 is "Yes (Yes)", the process proceeds to step S624. If the value of step S620 is "No (No)", the processor 130 returns to step S610 and continues the constant current charging procedure using the first charging rate.

[0133] In step S624, the processor 130 determines whether it is necessary to execute a temporary discharge procedure for the battery. The processor 130 may determine the necessity of executing the temporary discharge procedure based on the degree of use of the battery. For example, when the degree of use of the battery is equal to or greater than a threshold value, the value of step S624 becomes "Yes", and when it is not, the value of step S624 may be output as "No". If the value of step S624 is "Yes", the process proceeds to step S630. If the value of step S624 is "No", the process may proceed to step S640.

[0134] In this regard, even if the magnitude of the current impact is the same, as the battery deteriorates, the internal damage to the battery increases. Considering such deterioration characteristics, when it is determined that it is necessary to execute a temporary discharge procedure, the processor 130 may perform at least one of the operations of (i) determining the duration of the temporary discharge procedure so as to have a continuous or discrete negative correlation with the degree of use of the battery, and (ii) determining the magnitude of the constant current for the temporary discharge procedure so as to have a continuous or discrete negative correlation with the degree of use of the battery. That is, as the degree of use of the battery increases (i.e., as the battery deteriorates), the duration of the temporary discharge procedure and the magnitude of the constant current (discharge current) decrease continuously or discretely. The negative correlation may be defined as a predetermined function that takes the degree of use of the battery as an input variable and outputs at least one of the duration of the temporary discharge procedure and the magnitude of the discharge current.

[0135] As a result, there is a technical advantage that the level of the current impact applied to the battery when shifting from the constant current charging procedure related to the first charging rate to the temporary discharge procedure (i.e., the difference between the first charging rate and the magnitude of the discharge current), and the level of the current impact applied to the battery when shifting from the temporary discharge procedure to the constant current charging procedure related to the second charging rate (i.e., the difference between the magnitude of the discharge current and the adjusted second charging rate) are mitigated as the battery deteriorates.

[0136] In step S630, the processor 130 executes a temporary discharge procedure. For example, the processor 130 may request an external charger to pass a discharge current through the battery according to the discharge information of the temporary discharge procedure.

[0137] In step S640, the processor 130 executes a constant current charging procedure using the second charging rate.

[0138] In step S650, the processor 130 determines whether the SOC of the battery has reached the second reference SOC. If the value of step S650 is "Yes", the method in FIG. 6 may end. If the value of step S650 is "No", the processor 130 returns to step S640 and continues the constant current charging procedure using the second charging rate.

[0139] Although FIG. 6 illustrates ending when the SOC of the battery reaches the second reference SOC, this is merely an example. If the multi-stage charge and discharge procedure includes three or more constant current charging procedures, additional constant current charging procedures or constant voltage charging procedures may be subsequently executed.

[0140] Different from the foregoing embodiment of FIG. 5 that unconditionally executes the temporary discharge procedure, the foregoing embodiment of FIG. 6 is different in that the temporary discharge procedure can be selectively executed according to the degree of use of the battery.

[0141] FIG. 7 is a flowchart schematically showing a battery control method according to still another embodiment of the present invention. The method in FIG. 7 can be executed in response to the battery control device 100 receiving a message notifying the start of a battery charging procedure from an external charger or the like. In FIG. 7, the main body of each step can be each component of the battery control device 100 according to the present invention described above. For the convenience of explanation, it is assumed that the SOC of the battery at the time when the method in FIG. 7 is started is less than the first reference SOC.

[0142] Referring to FIGS. 1 to 4 and FIG. 7, in step S710, the processor 130 executes a constant current charging procedure using the first charging rate.

[0143] In step S720, the processor 130 determines whether the state of charge (SOC) of the battery, which is determined based on the voltage measurement value of the battery received from the measurement unit 110, has reached the first reference SOC. The voltage measurement value of the battery can be measured periodically or at predetermined time intervals by the measurement unit 110 while the battery is being charged at the first charging rate.

[0144] The first reference SOC is a preset value to prevent lithium deposition on the negative electrode of the battery when a constant current charging procedure using the first charging rate is performed on the battery. For example, the first reference SOC can be the SOC value or the preset SOC value at which lithium deposition begins to occur or the severity of lithium deposition is predicted to increase to a certain level when constant current charging is continued at the first charging rate starting from when the SOC of the battery is lower than the first reference SOC.

[0145] If the value of step S720 is "Yes (Yes)", the process proceeds to step S724. If the value of step S720 is "No (No)", the processor 130 returns to step S710 and continues the constant current charging procedure using the first charging rate.

[0146] In step S724, the processor 130 determines whether it is necessary to execute a temporary discharge procedure for the battery. The processor 130 can determine the necessity of executing a temporary discharge procedure based on the degree of use of the battery. For example, if the degree of use of the battery is equal to or greater than a threshold value, the value of step S724 is "Yes (Yes)", and otherwise, the value of step S724 can be output as "No (No)". If the value of step S724 is "Yes (Yes)", the process proceeds to step S726. If the value of step S724 is "No (No)", the process can proceed to step S742.

[0147] In this regard, when it is determined that it is necessary to execute a temporary discharge procedure, at least one of (i) an operation of determining the duration of the temporary discharge procedure so as to have a continuous or discrete negative correlation with the degree of battery usage, and (ii) an operation of determining the magnitude of the constant current for the temporary discharge procedure so as to have a continuous or discrete negative correlation with the degree of battery usage can be executed, which is common to that described above with reference to FIG. 6.

[0148] In step S726, the processor 130 determines an adjusted second charging rate based on the discharge information of the temporary discharge procedure (see Equation 2). The adjusted second charging rate is different from the original second charging rate based on the multi-stage charging protocol data.

[0149] In step S730, the processor 130 executes a temporary discharge procedure.

[0150] In step S740, the processor 130 executes a constant current charging procedure using the adjusted second charging rate (determined in step S726).

[0151] In step S742, the processor 130 executes a constant current charging procedure using the second charging rate.

[0152] In step S750, the processor 130 determines whether the SOC of the battery has reached the second reference SOC. If the value of step S750 is "Yes", the method of FIG. 7 can end. If the value of step S750 is "No", the processor 130 returns to step S740 or step S742 and continues the constant current charging procedure using the second charging rate. Here, when the value of step S724 is determined to be "Yes" and the value of step S750 is determined to be "No", it returns to step S740, while when the values of both step S724 and step S750 are determined to be "No", it can return to step S742.

[0153] FIG. 7 illustrates an example where charging ends when the SOC of the battery reaches a second reference SOC. If the multi-stage charging procedure includes three or more constant current charging procedures, additional constant current charging procedures or constant voltage charging procedures may be subsequently executed.

[0154] Unlike the foregoing embodiment of FIG. 5 in which a temporary discharge procedure is unconditionally executed, the foregoing embodiment of FIG. 7 is different in that when a temporary discharge procedure is required, a constant current charging procedure using the adjusted second charging rate is executed instead of the original second charging rate included in the multi-stage charging protocol data.

[0155] The embodiments of the present invention described above are not only realized by the apparatus and method, but may also be realized by a program that realizes 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 those skilled in the technical field to which the present invention pertains from the description of the above-described embodiments.

[0156] As described above, the present invention has been described with reference to limited embodiments and drawings. However, the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by those having ordinary knowledge in the technical field to which the present invention pertains within the equivalent scope of the technical idea and claims of the present invention. In addition, the present invention described above can be variously substituted, modified, and changed by those having ordinary knowledge in the technical field to which the present invention pertains without departing from the technical idea of the present invention. Therefore, it is not limited by the above-described embodiments and the accompanying drawings, and all or part of each embodiment can be selectively combined to be configured for various modifications.

Claims

1. A memory that stores multi-stage charging protocol data including a first charging rate, a second charging rate used for another constant current charging procedure following the constant current charging procedure using the first charging rate, and a first reference SOC preset according to lithium precipitation of the battery in the constant current charging procedure using the first charging rate. A processor that identifies the SOC of the battery. It includes: The processor: During the execution of the constant current charging procedure using the first charging rate, when the SOC of the battery reaches the first reference SOC, execute a temporary discharge procedure. Based on the discharge information of the temporary discharge procedure, determine an adjusted second charging rate different from the second charging rate. After the end of the temporary discharge procedure, execute a constant current charging procedure using the adjusted second charging rate, a battery control device.

2. It includes a measurement unit configured to measure the voltage or current of the battery and output a measurement value indicating the measured voltage or current. The processor identifies the SOC of the battery based on the measurement value received from the measurement unit. The battery control device according to claim 1.

3. The processor: Based on the amount of change in the SOC of the battery during the execution of the temporary discharge procedure included in the discharge information, determine the adjusted second charging rate. The battery control device according to claim 1.

4. The processor: Determine the adjusted second charging rate to be greater than the second charging rate so as to compensate for the amount of change in the SOC of the battery due to the temporary discharge procedure. The battery control device according to claim 2.

5. The memory: Further stores a second reference SOC preset according to lithium precipitation of the battery in the constant current charging procedure using the second charging rate. The battery control device according to claim 4.

6. The processor: Based on the first reference SOC, the second reference SOC, and the second charging rate, further determine the adjusted second charging rate. The battery control device according to claim 5.

7. The processor: When executing the constant-current charging procedure using the first charging rate, if the constant-current charging procedure using the second charging rate is executed immediately from the time when the SOC of the battery reaches the first reference SOC, the battery control device according to claim 6 calculates a reference time predicted to be required for the SOC of the battery to reach the second reference SOC from the first reference SOC.

8. The processor determines the adjusted second charging rate such that the sum of (i) the duration of the temporary discharging procedure included in the discharging information and (ii) the time required for the SOC of the battery to reach the second reference SOC by the constant-current charging procedure using the adjusted second charging rate immediately after the end of the temporary discharging procedure is the same as the reference time. The battery control device according to claim 7.

9. The processor determines the duration of the temporary discharging procedure so as to have a continuous or discrete negative correlation with the degree of use of the battery. The battery control device according to claim 8.

10. The processor determines the adjusted second charging rate to be proportional to the sum of the difference between the first reference SOC and the second reference SOC and the amount of SOC change due to the temporary discharging procedure, and inversely proportional to the difference between the reference time and the duration of the temporary discharging procedure included in the discharging information. The battery control device according to claim 7.

11. The processor executes the temporary discharging procedure so as to discharge the battery at a constant current equal to or lower than the first charging rate. The battery control device according to claim 1.

12. The processor determines the magnitude of the constant current for the temporary discharging procedure so as to have a continuous or discrete negative correlation with the degree of use of the battery. The battery control device according to claim 11.

13. The processor determines whether it is necessary to execute the temporary discharging procedure based on the degree of use of the battery, and if it is determined that it is necessary to execute the temporary discharging procedure, when the SOC of the battery reaches the first reference SOC, the temporary discharging procedure is executed. When it is determined that there is no need to execute the temporary discharge procedure, when the SOC of the battery reaches the first reference SOC, a constant current charging procedure using the second charging rate is executed without executing the temporary discharge procedure. The battery control device according to claim 1.

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

15. An electric vehicle including the battery control device according to any one of claims 1 to 13.

16. A battery control method executed by a battery control device, During the execution of a constant current charging procedure using a first charging rate, when the SOC of the battery reaches a first reference SOC preset according to lithium precipitation of the battery in the constant current charging procedure using the first charging rate, executing a temporary discharge procedure; Based on the discharge information of the temporary discharge procedure, determining an adjusted second charging rate different from the preset second charging rate to be used for another constant current charging procedure following the constant current charging procedure using the first charging rate; After the temporary discharge procedure ends, executing a constant current charging procedure using the adjusted second charging rate; A battery control method including:

17. The SOC of the battery is identified based on a measured value indicating a measured voltage or current of the battery. The battery control method according to claim 16.

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