Apparatus and method for managing battery open circuit voltage (OCV)-state of charge (SOC) profile

Abstract

The present invention discloses an apparatus and method for managing an open circuit voltage (OCV)-state of charge (SOC) profile of a battery. The apparatus according to the present invention includes a storage means for storing a plurality of OCV-SOC profiles having overlapping sections that overlap in a predetermined SOC range, and a control means coupled thereto. The control means may be configured to calculate a partial capacity of the battery in a SOC range of the overlapping sections while charging or discharging the battery, determine a decrease rate of a current partial capacity compared to a partial capacity when the battery is in a BOL state, select an OCV-SOC profile corresponding to the decrease rate from among the plurality of OCV-SOC profiles, change the current OCV-SOC profile to the selected OCV-SOC profile, and control charging or discharging the battery using the changed OCV-SOC profile.

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for managing an OCV-SOC profile of a battery, and more particularly to an apparatus and method for managing adaptive changes in the OCV-SOC profile of a battery based on the degree of deterioration of the battery.

[0002] This application claims priority based on Korean Patent Application No. 10-2021-0149216, filed on November 2, 2021, and the entire contents disclosed in the specification and drawings of that application are incorporated herein by reference. [Background technology]

[0003] As a battery ages, its characteristics, such as resistance and capacity, change. When the battery characteristics change, it is necessary to change the open circuit voltage (OCV)-state of charge (SOC) profile, which is the basis for estimating the state of charge (SOC).

[0004] The OCV-SOC profile is a curve that shows the 1:1 correspondence between SOC and OCV on an XY coordinate system. In the XY coordinate system, the X axis represents SOC and the Y axis represents OCV. The OCV-SOC profile defines the upper limit of the battery charge voltage and the lower limit of the battery discharge voltage. The OCV-SOC profile also provides a basis for determining SOC from OCV and vice versa.

[0005] Figure 1 shows an example of the OCV-SOC profile of a battery in the beginning of life (BOL) state and the middle of life (MOL) state. The BOL state means that the battery is not degraded, while the MOL state means that the battery has deteriorated as it has been repeatedly charged and discharged. The OCV-SOC profile in the MOL state shown in the figure is the profile when the battery capacity is 10% lower than in the BOL state.

[0006] 1, when the battery is in the BOL state, the open-circuit voltage range in which charging and discharging occur is 3.450V to 4.157V (hereinafter referred to as the BOL open-circuit voltage range). Also, when the battery is in the MOL state, the open-circuit voltage range in which charging and discharging occur is 3.3V to 4.158V (hereinafter referred to as the MOL open-circuit voltage range).

[0007] When the battery capacity drops below the threshold value in the BOL state, the battery management unit replaces the current OCV-SOC profile with an OCV-SOC profile appropriate for the MOL state. This is because the battery charge and discharge can only be safely controlled if the OCV-SOC profile is replaced as the battery capacity decreases.

[0008] As an example, the battery management unit changes the OCV-SOC profile from the solid line profile to the dotted line profile when the battery capacity is 10% or more lower than the capacity in the BOL state.

[0009] The MOL open-circuit voltage range has a higher upper limit and a lower limit than the BOL open-circuit voltage range. Therefore, if you measure the battery capacity while it is being charged or discharged in the MOL open-circuit voltage range, the capacity will be lower than the BOL capacity, but the capacity decrease will be less than 10% (e.g., 8%). This is because although the battery capacity decreases and the OCV-SOC profile changes, the open-circuit voltage range over which the capacity is calculated becomes slightly wider, and the chargeable / dischargeable capacity increases slightly by the amount of the wider open-circuit voltage range.

[0010] If the OCV-SOC profile were changed simply based on the amount of battery capacity loss, as in the past, the result would be that in the above example, the OCV-SOC profile would change again from the dotted line profile to the solid line profile.As the capacity loss measured in the MOL open-circuit voltage range with wider upper and lower limits no longer meets the condition for changing the OCV-SOC profile (i.e., the condition that the capacity loss is 10% or more), the OCV-OCV profile would return to the BOL state profile.

[0011] Furthermore, when the OCV-SOC profile returns to the BOL state profile, the capacity measured in the BOL open-circuit voltage section again decreases by more than the threshold value (10%) as the open-circuit voltage section narrows slightly to the BOL open-circuit voltage section. Therefore, the battery management device changes the OCV-SOC profile again from the solid line profile to the dotted line profile. Furthermore, after the OCV-SOC profile is changed, as the decrease in capacity measured in the MOL open-circuit voltage section, whose upper and lower limits are now wider, becomes less than the threshold value (e.g., 8%), a repeated profile switching phenomenon occurs in which the OCV-SOC profile again changes from the dotted line profile to the solid line profile.

[0012] The repeated switching of the OCV-SOC profile can reduce the safety and reliability of battery control, so a new method for managing the change of the OCV-SOC profile is desired. Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been devised in light of the background of the conventional technology described above, and has an object to provide an apparatus and method for managing the OCV-SOC profile of a battery, which can solve the problem of repeated switching of the OCV-SOC profile by establishing a new profile change criterion when managing the change of the OCV-SOC profile as the capacity of the battery decreases.

[0014] Another object of the present invention is to provide a system or an electric vehicle including a device for managing an OCV-SOC profile of a battery. [Means for solving the problem]

[0015] To achieve the above technical objective, the device for managing a battery OCV-SOC profile according to the present invention may include a memory means for storing a plurality of OCV-SOC profiles having overlapping sections that overlap within a predetermined SOC range, a measurement means for measuring operating characteristics of the battery including at least one of voltage, current, and temperature, and a control means operably coupled to the memory means and the measurement means.

[0016] Preferably, the control means may be configured to control charging or discharging of the battery based on an OCV-SOC profile corresponding to a degree of deterioration of the battery, calculate a partial capacity of the battery in the SOC range of the overlapping section while charging or discharging the battery, determine a decrease rate of the current partial capacity compared to the partial capacity when the battery was in a BOL state, and if the decrease rate satisfies a condition for changing an OCV-SOC profile, select an OCV-SOC profile corresponding to the decrease rate from among the plurality of OCV-SOC profiles, change the current OCV-SOC profile to the selected OCV-SOC profile, and control charging or discharging of the battery using the changed OCV-SOC profile.

[0017] According to one aspect, the control means may be configured to receive current measurements of the battery from the measurement means and calculate fractional capacities of the battery in the SOC range of the overlap interval using a current integration method.

[0018] According to another aspect, the control means may be configured to receive a current measurement value of the battery from the measurement means while the battery is being charged or discharged in an open circuit voltage section of a current OCV-SOC profile, determine a current capacity of the battery using a current integration method, record the determined current capacity in the storage means, and determine a current state of charge by integrating the current of the battery based on the current capacity.

[0019] Preferably, the control means may be configured to determine a first current accumulation amount when the state of charge corresponds to the lower limit of the SOC range of the overlapping section, determine a second current accumulation amount when the state of charge corresponds to the upper limit of the SOC range of the overlapping section, and determine the partial capacity as the difference between the first current accumulation amount and the second current accumulation amount.

[0020] According to one aspect, the control means may be configured to select an OCV-SOC profile corresponding to a predetermined first threshold from among the plurality of OCV-SOC profiles when the decrease rate corresponds to a predetermined first threshold, change the OCV-SOC profile that has been referenced until now to the selected OCV-SOC profile, and control charging or discharging of the battery using the changed OCV-SOC profile.

[0021] According to another aspect, the control means may be configured to select an OCV-SOC profile corresponding to a predetermined second threshold value from among the plurality of OCV-SOC profiles when the decrease rate corresponds to a predetermined second threshold value (greater than the first threshold value), change the OCV-SOC profile currently being referenced to the selected OCV-SOC profile, and control charging or discharging of the battery using the changed OCV-SOC profile.

[0022] To achieve the above technical objective, a method for managing an OCV-SOC profile of a battery according to the present invention may include the steps of: (a) storing a plurality of OCV-SOC profiles having overlapping sections that overlap within a predetermined state of charge (SOC) range in a storage means; (b) measuring operational characteristics of the battery, including at least one of voltage, current, and temperature; (c) controlling charging or discharging of the battery based on the OCV-SOC profile corresponding to a degree of deterioration of the battery; (d) calculating a partial capacity of the battery within the SOC range of the overlapping section while charging or discharging the battery; (e) determining a decrease rate of the current partial capacity compared to the partial capacity when the battery is in a BOL state; (f) if the decrease rate satisfies a condition for changing an OCV-SOC profile, selecting an OCV-SOC profile from the plurality of OCV-SOC profiles that corresponds to the decrease rate; and (g) changing the current OCV-SOC profile to the selected OCV-SOC profile and controlling charging or discharging of the battery using the changed OCV-SOC profile.

[0023] The technical object of the present invention can also be achieved by a system including the above-described device for managing the OCV-SOC profile of a battery and an electric vehicle. [Effects of the Invention]

[0024] According to the present invention, by establishing a new profile change criterion for changing the OCV-SOC profile as the battery capacity decreases, it is possible to solve the problem of repeated switching of the OCV-SOC profile referenced in battery control, thereby enabling safe and reliable control of battery charge and discharge based on an OCV-SOC profile that matches the decrease in battery capacity.

[0025] The drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further understand the technical concepts of the present invention as well as the content of the invention, and therefore the present invention should not be interpreted as being limited to only the matters depicted in the drawings. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a diagram showing an example of an OCV-SOC profile (solid line) of a battery in a BOL (Beginning Of Life) state and an OCV-SOC profile (dotted line) of a battery in a MOL (Middle Of Life) state. [Figure 2] 1 is a schematic configuration diagram of a management device for an OCV-SOC profile of a battery according to an embodiment of the present invention. [Figure 3] FIG. 2 shows an example of multiple OCV-SOC profiles stored in a storage means according to an embodiment of the present invention. [Figure 4] FIG. 1 is a flowchart illustrating a method for managing an OCV-SOC profile of a battery according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and claims should not be construed as being limited to their ordinary or dictionary meanings, but should be construed as having meanings and concepts corresponding to the technical ideas of the present invention, based on the principle that the inventor himself can appropriately define the concepts of terms in order to best explain the invention. Therefore, it should be understood that the embodiment described in this specification and the configurations shown in the drawings are merely the most preferred embodiment of the present invention, and do not represent the entire technical ideas of the present invention, and therefore various equivalents and modifications that can be substituted therefor may exist at the time of filing this application.

[0028] FIG. 2 is a diagram showing a schematic configuration of a management device 10 for an OCV-SOC profile of a battery 11 according to an embodiment of the present invention.

[0029] 2, the OCV-SOC profile management device 10 for the battery 11 manages the OCV-SOC profile used to control the operation of the battery 11. The operation of the battery 11 is charging or discharging. As described in the Background section, the OCV-SOC profile defines a 1:1 relationship between the OCV and the SOC. The battery 11 can be charged or discharged in the open circuit voltage section of the OCV-SOC profile.

[0030] The battery 11 may be a lithium secondary battery, but the present invention is not limited by the type of battery. Therefore, any secondary battery that can be repeatedly charged and discharged may be used as the battery 11. The battery 11 includes at least one unit cell. The unit cell may be a pouch-type cell, a cylindrical cell, or a prismatic cell. When there are multiple unit cells, the unit cells may be connected in series and / or in parallel.

[0031] In the embodiment of the present invention, it is assumed that the battery 11 includes one unit cell or multiple unit cells connected in series and / or parallel, but the present invention is not limited by the number of unit cells or the electrical connection relationship between the unit cells.

[0032] The battery 11 can provide discharge power to the load 12. The load 12 can be any device that receives power from the battery 11. The load 12 can be a motor of an electric vehicle, an electric or electronic device connected to a power grid, a power conversion device, or the like. The battery 11 can be charged by a charging device 13. The charging device 13 can be a charging station for an electric vehicle or a power conversion system (PCS) of a power storage system. It goes without saying that the present invention is not limited in any way by the type of the load 12 or the charging device 13.

[0033] Preferably, the device 10 may include a storage means 14 for storing a plurality of OCV-SOC profiles having overlapping sections that locally overlap within a preset range of state of charge (SOC).

[0034] FIG. 3 is a diagram showing an example of a plurality of OCV-SOC profiles stored in the storage means 14 according to an embodiment of the present invention.

[0035] 3, at least one of the multiple OCV-SOC profiles is an OCV-SOC profile when the battery 11 is in a BOL state (see solid line), and at least the other of the multiple OCV-SOC profiles is an OCV-SOC profile based on when the battery 11 is in an MOL state (a state in which the capacity is reduced by 10%) (see dotted line).

[0036] Although not shown, there may be two or more OCV-SOC profiles in the MOL state. For example, the storage means 14 may further store an OCV-SOC profile corresponding to an MOL state in which the capacity of the battery 11 has decreased by 15%, and an OCV-SOC profile corresponding to an MOL state in which the capacity of the battery 11 has decreased by 20%. It will be obvious to those skilled in the art that the rate of capacity decrease corresponding to each MOL state is not limited to the above.

[0037] Preferably, the multiple OCV-SOC profiles may have an overlapping section A within a preset SOC range. In the figure, the overlapping section A is shown as a square box. The SOC range corresponding to the overlapping section A is approximately 65% ​​to 100%. The position of the overlapping section A and the SOC range corresponding to the overlapping section can be changed as much as desired depending on the types of positive and negative electrode materials included in the battery 11.

[0038] It is very easy for a person skilled in the art to select the type of material so that the multiple OCV-SOC profiles have an overlapping section A. As an example, the positive electrode material can be a lithium transition metal oxide containing Ni, Co, and Mn, and the negative electrode material can be graphite.

[0039] Depending on the type and content of the positive electrode material and / or the negative electrode material, the position of the overlapping section A may shift or the width of the overlapping section A may vary. In addition, the SOC range corresponding to the overlapping section A may also shift or vary in width.

[0040] The SOC range corresponding to the overlap section A may be set through a charge / discharge cycle experiment of the battery 11. Through the charge / discharge cycle experiment of the battery 11, OCV-SOC profiles corresponding to a plurality of capacity loss rates may be obtained. The OCV-SOC profiles thus obtained may be stored in the storage means 14. For reference, the charge / discharge cycle experiment is an experiment in which the open circuit voltage of the battery 11 is measured according to the state of charge of the battery 11 while accurately measuring the capacity loss of the battery 11.

[0041] There is no particular limitation on the type of storage means 14, as long as it is capable of recording and erasing data and / or information. For example, storage means 14 may be a random access memory (RAM), a read-only memory (ROM), a register, a flash memory, a hard disk, or a magnetic recording medium.

[0042] The storage means 14 may be electrically connected to the control means 16 via, for example, a data bus so that the storage means 14 can be accessed by the control means 16 .

[0043] The storage means 14 stores and / or updates and / or deletes and / or transmits programs including various control logics executed by the control means 16, and / or data generated when the control logics are executed, and / or preset data, parameters, lookup information / tables, etc.

[0044] Returning to Figure 2, the device 10 may include measuring means 15. The measuring means 15 may periodically measure the voltage, current and temperature of the battery 11. The current may be a charging current or a discharging current.

[0045] Preferably, the measuring means 15 may include a voltage measuring unit 15a, a current measuring unit 15b, and a temperature measuring unit 15c.

[0046] The voltage measurement unit 15 a measures the voltage of the battery 11 at regular time intervals while the battery 11 is being charged or discharged, and outputs the measured voltage value to the control means 16 .

[0047] The voltage measurement unit 15a may be a voltage measurement circuit known in the art, and since voltage measurement circuits are well known, detailed description thereof will be omitted.

[0048] The current measuring unit 15b measures the current flowing through the battery 11 at regular time intervals and outputs the measured current value to the control means 16.

[0049] The current measurement unit 15b may be a current measurement circuit known in the art. The current measurement unit 15b may be a Hall sensor or a sense resistor that outputs a voltage value corresponding to the magnitude of the current. The voltage value can be converted into a current value according to Ohm's law.

[0050] The temperature measurement unit 15c measures the temperature of the battery cell 11 at regular time intervals while the battery 11 is being charged or discharged, and outputs the measured temperature value to the control means 16.

[0051] The temperature measurement unit 15c may be a temperature measurement circuit known in the art. The temperature measurement unit 15c may be a thermocouple or a temperature measurement element that outputs a voltage value corresponding to the temperature. The voltage value can be converted into a temperature value using a voltage-to-temperature conversion lookup table (function).

[0052] The device 10 may also include a control means 16 operatively coupled to the storage means 14 and the measurement means 15 .

[0053] The control means 16 may control charging or discharging of the battery 11 based on an OCV-SOC profile corresponding to the degree of deterioration of the battery 11. In one example, the control means 16 may charge the battery 11 up to an upper limit voltage of the OCV-SOC profile, or may discharge the battery 11 up to a lower limit voltage of the OCV-SOC profile. In another example, the control means 16 may measure the open circuit voltage (OCV) of the battery 11 using the voltage measurement unit 15a after the battery 11 maintains an unloaded state for a predetermined time, and determine the state of charge (SOC) corresponding to the open circuit voltage by referring to the OCV-SOC profile.

[0054] Furthermore, the control means 16 may calculate a partial capacity of the battery in an SOC range (e.g., 65% to 100%) corresponding to the overlap interval A while the battery 11 is being charged or discharged. The partial capacity may be the increase in capacity when the battery 11 is charged from the lower limit to the upper limit of the SOC range corresponding to the overlap interval A, or the decrease in capacity when the battery 11 is discharged from the upper limit to the lower limit of the SOC range corresponding to the overlap interval A. When the coulombic efficiency of the battery 11 is 1, the increase in capacity and the decrease in capacity are substantially the same.

[0055] To calculate the partial capacity, the control means 16 may receive current measurement values ​​of the battery 11 from the current measurement unit 15b while the battery 11 is being charged or discharged in the SOC range corresponding to the overlap section A. The control means 16 may also calculate the partial capacity of the battery 11 in the SOC range of the overlap section A by integrating the current measurement values ​​using a current integration method. When integrating the current measurement values, charging currents are added up as positive values ​​and discharging currents are added up as negative values.

[0056] The control means 16 may determine the capacity of the battery 11 and record it in the storage means 14 in order to determine the state of charge (SOC) of the battery 11 while the battery 11 is being charged or discharged. That is, the control means 16 may determine the capacity of the battery 11 by integrating the current of the battery 11 measured by the current measurement unit 15b while the battery 11 is being charged from the lower limit to the upper limit of the open-circuit voltage section of the OCV-SOC profile at the current time point, or while the battery 11 is being discharged from the upper limit to the lower limit of the open-circuit voltage section of the OCV-SOC profile at the current time point, and record it in the storage means 14.

[0057] In addition, the control means 16 may determine the current state of charge (SOC) by integrating the current of the battery 11 based on the current capacity while the battery 11 is being charged or discharged. Specifically, the control means 16 may measure the open-circuit voltage of the battery 11 when the battery 11 is in an unloaded state, determine the SOC corresponding to the measured open-circuit voltage by referring to the OCV-SOC profile at the current time, determine the determined SOC as an initial SOC value, periodically update the current integration value when the battery 11 starts charging or discharging, determine a change in the SOC by dividing the current integration value calculated up to now by the current capacity of the battery 11, and determine the current SOC by adding the change in the SOC to the initial SOC value. This method of determining the SOC is widely known in the art as a current integration method.

[0058] In another example, the control means 16 may use an extended Kalman filter to determine the state of charge of the battery 11. To this end, the control means 16 may input the operating characteristic values ​​of the battery 11 measured via the voltage measurement unit 15a, the current measurement unit 15b, and the temperature measurement unit 15c into the extended Kalman filter while the battery 11 is being charged or discharged, thereby determining the state of charge of the battery 11 in real time. Here, the operating characteristic values ​​include measured values ​​related to the voltage, current, and temperature of the battery 11.

[0059] Extended Kalman filters, which are capable of determining the state of charge from the voltage, current and temperature of the battery 11, are well known in the art.

[0060] For an example of estimation of the state of charge using an extended Kalman filter, see the paper by Gregory L. Plett, “Extended Kalman filtering for battery management systems of LiPB-based HEV battery packs Parts 1, 2 and 3” (Journal of Power Source 134, 2004, pp. 252-261), which is incorporated herein by reference.

[0061] Preferably, the control means 16 may determine a first accumulated current amount up to a point in time when the state of charge of the battery 11 corresponds to the lower limit of the SOC range of the overlap section A. The control means 16 may determine a second accumulated current amount up to a point in time when the state of charge of the battery 11 corresponds to the upper limit of the SOC range of the overlap section A. Furthermore, the control means 16 may determine the difference between the first accumulated current amount and the second accumulated current amount as the partial capacity corresponding to the SOC range of the overlap section A.

[0062] Preferably, the control means 16 is capable of determining the rate of decrease of the current fractional capacity compared to the fractional capacity when the battery 11 is in the BOL state.

[0063] As an example, when battery 11 is in a BOL state, if the calculated partial capacity in the SOC range of overlap section A (65% to 100%) is 35 Ah, and when battery 11 is in an MOL state, if the calculated partial capacity in the SOC range of overlap section A is 31.5 Ah, the reduction rate of the partial capacity may be 10% (3.5 / 35).

[0064] As another example, when battery 11 is in a BOL state, if the calculated partial capacity in the SOC range of overlap section A (65% to 100%) is 35 Ah, and when battery 11 is in a MOL state, if the calculated partial capacity in the SOC range of overlap section A is 28 Ah, the reduction rate of the partial capacity may be 20% (7 / 35).

[0065] Preferably, if the coulombic efficiency of battery 11 is not 1, the partial capacity calculation criteria are equally applicable. That is, if the partial capacity in the BOL state is measured when battery 11 is being charged, the partial capacity in the MOL state can also be measured when battery 11 is being charged. Conversely, if the partial capacity in the BOL state is measured when battery 11 is being discharged, the partial capacity in the MOL state can also be measured when battery 11 is being discharged.

[0066] Furthermore, if the rate of decrease satisfies the conditions for changing the OCV-SOC profile, the control means 16 selects an OCV-SOC profile corresponding to the rate of decrease from among the multiple OCV-SOC profiles recorded in the storage means 14, changes the current OCV-SOC profile to the selected OCV-SOC profile, and controls charging or discharging of the battery 11 using the changed OCV-SOC profile, or measures the open-circuit voltage of the battery 11 and then estimates the state of charge from the selected OCV-SOC profile.

[0067] In one example, when the decrease rate corresponds to a predetermined first threshold value (e.g., 10%), the control means 16 selects an OCV-SOC profile corresponding to the first threshold value from among a plurality of OCV-SOC profiles, changes the current OCV-SOC profile to the selected OCV-SOC profile, and controls charging or discharging of the battery 11 using the changed OCV-SOC profile, or measures the open-circuit voltage of the battery 11 and then estimates the state of charge from the selected OCV-SOC profile.

[0068] In another example, when the decrease rate corresponds to a predetermined second threshold (greater than the first threshold, for example, 20%), the control means 16 selects an OCV-SOC profile corresponding to the second threshold from among multiple OCV-SOC profiles, changes the current OCV-SOC profile to the selected OCV-SOC profile, and controls charging or discharging of the battery 11 using the changed OCV-SOC profile, or measures the open-circuit voltage of the battery 11 and then estimates the state of charge from the selected OCV-SOC profile.

[0069] In the present invention, the threshold values ​​are not limited to the first and second threshold values. Therefore, three or more threshold values ​​may be set. In this case, the OCV-SOC profile recorded in the storage means 14 may be further subdivided based on the reduction rate of the partial capacity.

[0070] Preferably, the plurality of OCV-SOC profiles can be recorded in the storage means 14 as a data structure that allows the corresponding OCV-SOC profile to be identified based on the rate of decrease in partial capacity.

[0071] In one example, each OCV-SOC profile may be generated as a lookup table and recorded in the storage means 14. An identification code may be assigned to each lookup table so that the lookup table can be identified by the rate of decrease in partial capacity. In this case, the control means 16 may identify and select a corresponding lookup table by referring to the rate of decrease in partial capacity calculated in the SOC range of overlap section A, generate an OCV-SOC profile by referring to the identified lookup table, and control the charging or discharging of the battery 11 using the generated OCV-SOC profile.

[0072] In the present invention, the control logic for selecting a lookup table based on the rate of decrease in the partial capacity of the battery 11 is substantially similar to the control logic for selecting an OCV-SOC profile based on the rate of decrease in the partial capacity of the battery 11.

[0073] In the present invention, the control means 16 may be a control circuit. The control means 16 may optionally include a processor, application specific integrated circuits (ASICs), other chipsets, logic circuits, registers, communication modems, data processing devices, and the like, known in the art, to execute the various control logics described above. When the control logic is implemented in software, the control means 16 may be implemented as a collection of program modules. In this case, the program modules may be stored in memory and executed by the processor. The memory may be located inside or outside the processor and may be connected to the processor by various well-known computer components. The memory may also be included in the storage means 14 of the present invention. Furthermore, the term "memory" refers to any device that stores information, regardless of the type of device, and does not refer to a specific memory device.

[0074] The various control logics of the control unit 16 may be combined together, and the combined control logic may be written in a computer-readable code system and stored on a computer-readable recording medium. There are no particular limitations on the type of recording medium as long as it is accessible by a processor included in a computer. For example, the recording medium may include at least one selected from the group consisting of read-only memory (ROM), random access memory (RAM), registers, compact disc read-only memory (CD-ROM), magnetic tape, hard disk, floppy disk, and optical data storage device.

[0075] The code system can be stored and executed in a distributed manner on computers connected via a network, and functional programs, codes, and code segments for realizing the combined control logic can be easily construed by programmers skilled in the art to which the present invention pertains.

[0076] The device 10 according to the above-described embodiment of the present invention may be included in a power storage system known as an energy storage system (ESS), an electric vehicle system, or an uninterruptible power supply system. Alternatively, the device 10 may be included in any system that receives power from a battery. The device 10 is preferably integrated into a control element of the system in which it is included. The device 10 calculates the partial capacity of the battery in the system in which it is included while the battery is being charged or discharged within the SOC range of overlap section A, determines the rate of decrease of the currently calculated partial capacity compared to the partial capacity when the battery is in a BOL state, and, when the rate of decrease reaches a threshold, changes the OCV-SOC profile referenced in controlling the charging and discharging of the battery to a more suitable profile that reflects the battery's degradation level. This enables optimal control of the charging and discharging of the battery based on the battery's degradation level.

[0077] In the present invention, an electric vehicle refers to a vehicle that is driven by a motor, such as an electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, etc. The vehicle may have two, three or four wheels.

[0078] FIG. 4 is a flowchart showing the overall flow of a method for managing an OCV-SOC profile of a battery according to an embodiment of the present invention.

[0079] In the flowchart, a preceding step is not necessarily executed before a succeeding step. The order of the preceding and succeeding steps may be reversed, or a particular step may be moved before or after another step. Therefore, it should be understood that the present invention is not limited in any way by the order in which the steps are arranged.

[0080] Preferably, the steps shown in FIG. 4 may be carried out by the control means 16.

[0081] First, in step S10, the control means 16 stores, in the storage means 14, a plurality of OCV-SOC profiles having overlapping sections (see A in FIG. 3 ) that locally overlap within a predetermined range of state of charge (SOC). The plurality of OCV-SOC profiles may be provided by the manufacturer of the battery 11. The control means 16 may receive (transmit) the plurality of OCV-SOC profiles from the battery manufacturer's system via an input / output interface (I / O interface) (not shown) or a communication interface (not shown), and record the plurality of OCV-SOC profiles in the storage means 14. Preferably, the plurality of OCV-SOC profiles may be stored in the form of a lookup table, and each lookup table may be assigned an identification code so that it can be uniquely identified based on the rate of decrease in partial capacity.

[0082] Also, in step S20, the control means 16 measures operating characteristics including at least one of the battery voltage, current, and temperature. Furthermore, the control means 16 may record data relating to the operating characteristics together with a timestamp in the storage means 14. The operating characteristic data may be used to estimate the state of charge of the battery 11 and calculate the partial capacity.

[0083] Furthermore, in step S30, the control means 16 may control the charging or discharging of the battery based on the OCV-SOC profile at the current time point corresponding to the degree of deterioration of the battery.

[0084] In one example, when the battery 11 is in a BOL state, the current OCV-SOC profile may be a BOL state profile. In another example, when the battery 11 is in an MOL state, the current OCV-SOC profile may be a MOL state profile.

[0085] Preferably, the current OCV-SOC profile can be changed to another OCV-SOC profile in a subsequent step based on the rate of decrease in the partial capacity.

[0086] In step S40, the control means 16 calculates the partial capacity of the battery 11 in the SOC range of the preset overlap section while the battery 11 is being charged or discharged.

[0087] Preferably, the control means 16 may integrate the current measurements of the battery 11 in the SOC range of the overlap section A to calculate the partial capacity of the battery 11 .

[0088] In one example, in step S40, the control means 16 may determine the current capacity of the battery by integrating the current measurement values ​​of the battery while the battery 11 is being charged or discharged in the open circuit voltage section of the current OCV-SOC profile, determine the state of charge of the battery by integrating the charging current and discharging current of the battery based on the current capacity, determine a first accumulated current amount up to that point when the state of charge corresponds to the lower limit of the SOC range of the overlap section A, and determine a second accumulated current amount up to that point when the state of charge corresponds to the upper limit of the SOC range of the overlap section A, and determine the difference between the first accumulated current amount and the second accumulated current amount as the partial capacity.

[0089] Preferably, the current capacity of the battery 11 may be determined in advance in a charge / discharge cycle of the battery 11 performed prior to calculating the partial capacity, and then recorded in the storage means 14. In addition, the current capacity of the battery 11 recorded in the storage means 14 may be referred to when determining the state of charge of the battery 11.

[0090] After step S40, step S50 is performed.

[0091] In step S50, the control means 16 determines the rate of decrease of the current fractional capacity compared to the fractional capacity when the battery 11 is in the BOL state.

[0092] Also, in step S60, if the rate of decrease in partial capacity satisfies the condition for changing the OCV-SOC profile, the control means 16 selects an OCV-SOC profile corresponding to the rate of decrease from among the multiple OCV-SOC profiles recorded in the storage means 14.

[0093] Furthermore, in step S70, the control means 16 changes the OCV-SOC profile that has been referenced up to now to the selected OCV-SOC profile. Furthermore, in step S80, the control means 16 controls the charging or discharging of the battery using the changed OCV-SOC profile.

[0094] Optionally, the control means 16 may estimate the state of charge of the battery 11 using the OCV-SOC profile selected in step S80.

[0095] That is, the control means 16 may measure the open-circuit voltage of the battery 11 using the voltage measurement unit 15a when the battery 11 is in an unloaded state, determine the state of charge (SOC) corresponding to the measured open-circuit voltage by referring to the selected OCV-SOC profile, and set the determined state of charge to an initial value of the state of charge before the battery 11 is charged or discharged. In this case, the control unit 16 may integrate the current measurement values ​​while the battery 11 is being charged or discharged, and determine the current state of charge of the battery 11 by adding together the initial value of the state of charge determined from the open-circuit voltage and the amount of change in the state of charge corresponding to the integrated current value up to the present time.

[0096] According to a detailed embodiment of steps S60 to S80, when the rate of decrease in partial capacity corresponds to a predetermined first threshold value (e.g., 10%), the control means 16 selects an OCV-SOC profile corresponding to the first threshold value from among the multiple OCV-SOC profiles recorded in the storage means 14, changes the OCV-SOC profile that has been referenced until now to the selected OCV-SOC profile, and controls the charging or discharging of the battery 11 using the changed OCV-SOC profile, or estimates the state of charge of the battery 11.

[0097] In another example, when the rate of decrease in partial capacity corresponds to a predetermined second threshold value (greater than the first threshold value, for example, 20%), the control means 16 selects an OCV-SOC profile corresponding to the second threshold value from among the multiple OCV-SOC profiles recorded in the storage means 14, changes the OCV-SOC profile that has been referenced until now to the selected OCV-SOC profile, and controls the charging or discharging of the battery 11 using the changed OCV-SOC profile, or estimates the state of charge of the battery 11.

[0098] In the present invention, the threshold levels are not limited to the first and second threshold levels, but may be set to three or more levels. It will be obvious to a person skilled in the art to which the present invention pertains that if the threshold levels increase to three or more levels, the OCV-SOC profile recorded in the storage means 134 may also increase to three or more levels.

[0099] According to the above-described embodiment of the present invention, when changing the OCV-SOC profile based on the degree of battery deterioration, the profile change criteria are newly changed, thereby solving the conventional problem of repeated switching of the OCV-SOC profile, and thereby making it possible to optimally control the charging and discharging of the battery based on the degree of battery deterioration.

[0100] In describing various embodiments of the present invention, components designated as "means" should be understood to be functionally distinct elements, not necessarily physically distinct elements. Therefore, each component may be selectively integrated with other components, or each component may be divided into subcomponents for efficient execution of control logic. However, it will be apparent to those skilled in the art that even if components are integrated or divided, as long as the same function is recognized, the integrated or divided components should also be construed as falling within the scope of the present invention.

[0101] Although the present invention has been described above using limited embodiments and drawings, the technical concept of the present invention is not limited to these in any way, and it goes without saying that a person having ordinary knowledge in the technical field to which the present invention pertains can make various modifications and variations within the scope of the technical concept of the present invention and the equivalent scope of the claims. [Explanation of symbols]

[0102] 11 Battery 12 Load 13 Charging device 14 Memory means 15 Measurement means 15a Voltage measurement section 15b Current measurement section 15c Temperature measurement part 16 Control Measures

Claims

1. a storage means for storing a plurality of open circuit voltage (OCV)-state of charge (SOC) profiles having overlapping sections that overlap within a predetermined range of state of charge (SOC); a measuring means for measuring operating characteristics of the battery, including at least one of voltage, current, and temperature; control means operably coupled to said storage means and said measurement means; Including, The control means controlling charging or discharging of the battery based on a first open circuit voltage (OCV)-state of charge (SOC) profile corresponding to an early-life (BOL) state of the battery; Calculating a partial capacity of the battery within a state of charge (SOC) range of the overlapping section while the battery is being charged or discharged; determining a percentage loss of partial capacity at mid-life (MOL), after repeated charging and discharging of the battery, compared to the partial capacity when the battery was at the BOL; in response to the rate of decrease satisfying a change condition of the first open circuit voltage (OCV)-state of charge (SOC) profile; selecting a second OCV-SOC profile from the plurality of OCV-SOC profiles that corresponds to a state of the MOL; changing the first open circuit voltage (OCV)-state of charge (SOC) profile to a selected open circuit voltage (OCV)-state of charge (SOC) profile in the MOL; Controlling the charging or discharging of a battery using a modified open circuit voltage (OCV)-state of charge (SOC) profile It is configured as follows: the first open circuit voltage (OCV)-state of charge (SOC) profile is included in the plurality of open circuit voltage (OCV)-state of charge (SOC) profiles; an upper limit voltage of the first OCV-SOC profile is lower than an upper limit voltage of the second OCV-SOC profile; The lower limit voltage of the first OCV-SOC profile is greater than the lower limit voltage of the second OCV-SOC profile. A device for managing the battery's open circuit voltage (OCV)-state of charge (SOC) profile.

2. 2. The device for managing a battery open circuit voltage (OCV)-state of charge (SOC) profile according to claim 1, wherein the control means is configured to receive the current measurement value of the battery from the measurement means and calculate the partial capacity of the battery in the state of charge (SOC) range of the overlapping section using a current integration method.

3. 2. The device for managing a battery open circuit voltage (OCV)-state of charge (SOC) profile according to claim 1, wherein the control means is configured to receive a current measurement value of the battery from the measurement means while the battery is being charged or discharged in an open circuit voltage section of a current open circuit voltage (OCV)-state of charge (SOC) profile, determine a current capacity of the battery using a current integration method, record the determined current capacity in the storage means, and integrate the current of the battery based on the current capacity to determine a current state of charge.

4. 4. The device for managing a battery open circuit voltage (OCV)-state of charge (SOC) profile according to claim 3, wherein the control means is configured to determine a first current integration amount when the state of charge corresponds to a lower limit of a state of charge (SOC) range of the overlapping section, determine a second current integration amount when the state of charge corresponds to an upper limit of a state of charge (SOC) range of the overlapping section, and determine a difference between the first current integration amount and the second current integration amount as the partial capacity.

5. the control means selects an open circuit voltage (OCV)-state of charge (SOC) profile corresponding to a predetermined first threshold value from among the plurality of open circuit voltage (OCV)-state of charge (SOC) profiles when the decrease rate corresponds to a predetermined first threshold value; Change the currently referenced open circuit voltage (OCV)-state of charge (SOC) profile to the selected open circuit voltage (OCV)-state of charge (SOC) profile; 2. The battery open circuit voltage (OCV)-state of charge (SOC) profile management device of claim 1, configured to control charging or discharging of the battery using a modified open circuit voltage (OCV)-state of charge (SOC) profile.

6. the control means selects an open circuit voltage (OCV)-state of charge (SOC) profile corresponding to a second threshold value from among the plurality of open circuit voltage (OCV)-state of charge (SOC) profiles when the decrease rate corresponds to a predetermined second threshold value (greater than the first threshold value); and Change the currently referenced open circuit voltage (OCV)-state of charge (SOC) profile to the selected open circuit voltage (OCV)-state of charge (SOC) profile; 6. The battery open circuit voltage (OCV)-state of charge (SOC) profile management device according to claim 5, configured to control charging or discharging of the battery using the modified open circuit voltage (OCV)-state of charge (SOC) profile.

7. A system comprising a device for managing an open circuit voltage (OCV)-state of charge (SOC) profile of a battery according to any one of claims 1 to 6.

8. An electric vehicle comprising the device for managing the open circuit voltage (OCV)-state of charge (SOC) profile of a battery according to any one of claims 1 to 6.

9. (a) storing a plurality of open circuit voltage (OCV)-state of charge (SOC) profiles having overlapping sections that overlap within a predetermined range of state of charge (SOC) in a storage means; (b) measuring operating characteristics of the battery, including at least one of voltage, current, and temperature; (c) controlling charging or discharging of the battery based on a first open circuit voltage (OCV)-state of charge (SOC) profile corresponding to a beginning of life (BOL) state of the battery; (d) calculating a fractional capacity of the battery within the overlapping state of charge (SOC) range while the battery is being charged or discharged; (e) determining a percentage loss of fractional capacity at mid-life (MOL), after repeated charging and discharging of the battery, compared to the fractional capacity when the battery was at the BOL; (f) selecting a second OCV-SOC profile from the plurality of OCV-SOC profiles in response to the rate of decrease satisfying a condition for changing the first OCV-SOC profile, the second OCV-SOC profile corresponding to the state of the MOL; (g) changing the first open circuit voltage (OCV)-state of charge (SOC) profile in the MOL to the selected open circuit voltage (OCV)-state of charge (SOC) profile, and controlling charging or discharging of a battery using the changed open circuit voltage (OCV)-state of charge (SOC) profile; Including, the first open circuit voltage (OCV)-state of charge (SOC) profile is included in the plurality of open circuit voltage (OCV)-state of charge (SOC) profiles; an upper limit voltage of the first OCV-SOC profile is lower than an upper limit voltage of the second OCV-SOC profile; The lower limit voltage of the first OCV-SOC profile is greater than the lower limit voltage of the second OCV-SOC profile. How to manage the battery's open circuit voltage (OCV)-state of charge (SOC) profile.

10. In the step (d), 10. The method for managing a battery open circuit voltage (OCV)-state of charge (SOC) profile according to claim 9, further comprising integrating current measurements of the battery in the range of the state of charge (SOC) of the overlapping section to calculate a partial capacity of the battery.

11. determining a current capacity of the battery by integrating current measurements of the battery while the battery is being charged or discharged in an open circuit voltage section of a current open circuit voltage (OCV)-state of charge (SOC) profile; determining a state of charge of the battery by integrating the current of the battery based on the current capacity; 10. The method of claim 9, further comprising:

12. The step (d) determining a first current integration amount up to a point in time when the state of charge corresponds to a lower limit of a range of state of charge (SOC) of the overlapping section; determining a second current integration amount up to a point when the state of charge corresponds to an upper limit of a range of state of charge (SOC) of the overlapping section; determining a difference between the first integrated current amount and the second integrated current amount as the partial capacity; The method for managing an open circuit voltage (OCV)-state of charge (SOC) profile of a battery according to claim 11, comprising:

13. In the step (f), when the decrease rate corresponds to a predetermined first threshold value, selecting an OCV-SOC profile corresponding to the first threshold value from among the plurality of OCV-SOC profiles; 10. The method for managing an open circuit voltage (OCV)-state of charge (SOC) profile of a battery according to claim 9, wherein in step (g), the open circuit voltage (OCV)-state of charge (SOC) profile currently being referenced is changed to the selected OCV-state of charge (SOC) profile, and charging or discharging of the battery is controlled using the changed open circuit voltage (OCV)-state of charge (SOC) profile.

14. In the step (f), when the decrease rate corresponds to a predetermined second threshold value (greater than the first threshold value), an open circuit voltage (OCV)-state of charge (SOC) profile corresponding to the second threshold value is selected from the plurality of open circuit voltage (OCV)-state of charge (SOC) profiles; 14. The method for managing an open circuit voltage (OCV)-state of charge (SOC) profile of a battery according to claim 13, wherein in step (g), the open circuit voltage (OCV)-state of charge (SOC) profile currently being referenced is changed to the selected OCV-state of charge (SOC) profile, and charging or discharging of the battery is controlled using the changed open circuit voltage (OCV)-state of charge (SOC) profile.

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