Battery management system, battery management method, battery pack and electric vehicle

Abstract

To update a multi-stage constant-current charge map according to an operational state of a battery based on a battery voltage and current monitored during charging using the multi-stage constant-current charge map.SOLUTION: In an electric vehicle 1, a battery pack 10 comprises: a voltage sensor 111 to measure a battery voltage; a current sensor 112 to measure a battery current; a memory unit 120 to store a charge map recording a correspondence between first to n-th reference SOC ranges and first to n-th reference currents for multi-stage constant-current charging; and a control unit 140. The control unit is configured to: in response to a charge start command, start constant current charging using a k-th reference current corresponding to a k-th reference SOC range to which an SOC of a battery B belongs among the first to n-th reference SOC ranges; and switch to constant voltage charging using a k-th reference voltage in response to the battery voltage reaching the k-th reference voltage corresponding to the k-th reference SOC range before the SOC of the battery reaches an upper limit value of the k-th reference SOC range.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a technique for controlling charging of a battery.

[0002] This application claims priority to Korean Patent Application No. 10-2020-0101934, filed on August 13, 2020, and the entire contents disclosed in the specification and drawings of that application are incorporated herein by reference. [Background technology]

[0003] Recently, as the demand for portable electronic products such as notebook PCs, video cameras, and mobile phones has increased sharply and the development of electric vehicles, energy storage batteries, robots, satellites, etc. has progressed in earnest, research into high-performance batteries that can be repeatedly charged and discharged is progressing actively.

[0004] Currently, commercial batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. Of these, lithium batteries are in the spotlight due to their advantages over nickel-based batteries, such as almost no memory effect, freedom to charge and discharge, a very low self-discharge rate, and high energy density.

[0005] In charging a battery with a constant current, if the charging current rate is small, it will take a very long time to fully charge the battery, while if the charging current rate is too high, it will have the side effect of causing the battery to deteriorate quickly.

[0006] One of the charging protocols proposed to solve the above problems is "multi-stage constant-current charging," which adjusts the current rate of the charging current stepwise according to the state of charge and voltage of the battery during charging. The current rate is a value obtained by dividing the charging current by the maximum capacity of the battery, and is also called "C-rate" and uses the unit "C." The multi-stage constant-current charging map includes at least one data array in which a correspondence between a plurality of current rates and a plurality of SOC (State of Charge) ranges is recorded. The charging stage using the multi-stage constant-current charging map is performed by repeating the process of supplying a charging current of the next current rate to the battery every time the SOC of the battery reaches the upper limit of each SOC range.

[0007] The further a battery degrades from its beginning of life (BOL), the more accelerated degradation may occur at the same current rate.

[0008] However, charging using a conventional multi-stage constant current charging map has the problem that it does not take into account battery degradation. [Prior art document] [Patent documents] Patent Document 1: U.S. Patent Application Publication No. 2015 / 0340885 Patent Document 2: International Publication No. 2011 / 061902 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of the above problems, and aims to provide a battery management system, a battery management method, a battery pack, and an electric vehicle that update a multi-stage constant current charging map based on the battery voltage and battery current monitored during charging using the multi-stage constant current charging map.

[0010] Another object of the present invention is to provide a battery management system, a battery management method, a battery pack, and an electric vehicle that update the current rate for each remaining SOC range among a plurality of SOC ranges based on the update result for the current rate for some SOC ranges, even if the charging phase is terminated with only some of the plurality of SOC ranges remaining.

[0011] Other objects and advantages of the present invention will become apparent from the following description and the accompanying drawings, in which: FIG. 1 is a block diagram of a method for manufacturing a semiconductor device according to the present invention; [Means for solving the problem]

[0012] According to one aspect of the present invention, a battery management system includes a voltage sensor for measuring a battery voltage, a current sensor for measuring a battery current, a memory unit for storing a charging map in which a correspondence between 1st to nth reference SOC ranges and 1st to nth reference currents for multi-stage constant current charging is recorded, and a control unit for starting constant current charging using a kth reference current corresponding to a kth reference SOC range to which a battery SOC belongs among the 1st to nth reference SOC ranges in response to a charging start command, and switching from the constant current charging to constant voltage charging using the kth reference voltage in response to the battery voltage reaching a kth reference voltage corresponding to the kth reference SOC range before the SOC of the battery reaches an upper limit value of the kth reference SOC range during the constant current charging.

[0013] The control unit may switch from the constant voltage charging to constant current charging using a (k+1)th reference current corresponding to the (k+1)th reference SOC range in response to the SOC of the battery reaching the upper limit value of the kth reference SOC range during the constant voltage charging.

[0014] The control unit may update the kth reference current of the charging map based on the current history of the battery current over the charging period of the constant voltage charging in response to the SOC of the battery reaching the upper limit value of the kth reference SOC range during the constant voltage charging.

[0015] The controller may be configured to determine an average current during the charging period based on the current history, and to update the kth reference current to be equal to the average current.

[0016] The controller may be configured to determine an average current during the charging period based on the current history, and to update the kth reference current equal to a sum of a product of the kth reference current and a first weight and a product of the average current and a second weight.

[0017] The first weight and the second weight may each be a positive number less than 1, and a sum of the first weight and the second weight may be 1.

[0018] The controller may be configured to update each of the remaining reference currents, except for the kth reference current, based on a ratio of the updated kth reference current to the kth reference current.

[0019] A battery pack according to another aspect of the present invention includes the battery management system. An electric vehicle according to yet another aspect of the present invention includes the battery pack.

[0020] A battery management method according to yet another aspect of the present invention includes the steps of: reading out, in response to a charging start command, a charging map in which correspondences between first to nth reference SOC ranges for multi-stage constant current charging and first to nth reference currents are recorded; starting constant current charging using a kth reference current corresponding to a kth reference SOC range among the first to nth reference SOC ranges to which the SOC of the battery belongs; and switching from the constant current charging to constant voltage charging using the kth reference voltage in response to the battery voltage reaching a kth reference voltage corresponding to the kth reference SOC range before the SOC of the battery reaches an upper limit value of the kth reference SOC range during the constant current charging.

[0021] The battery management method may further include a step of switching from the constant voltage charging to constant current charging using a (k+1)th reference current corresponding to the (k+1)th reference SOC range in response to the SOC of the battery reaching the upper limit value of the kth reference SOC range during the constant voltage charging. The battery management method may further include a step of updating a kth reference current of a charging map based on a current history of a battery current over a charging period of the constant voltage charging in response to the SOC of the battery reaching the upper limit value of the kth reference SOC range during the constant voltage charging. The step of updating the kth reference current of the charging map may include determining an average current during the charging period based on the current history, and updating the kth reference current to be equal to the average current. The battery management method may further include determining a ratio between the kth reference current and the updated kth reference current, and updating each of the remaining reference currents except for the kth reference current based on the ratio. Effect of the Invention

[0022] According to at least one embodiment of the present invention, the multi-stage constant current charging map can be updated based on the battery voltage and battery current monitored during charging using the multi-stage constant current charging map.

[0023] In addition, according to at least one embodiment of the present invention, even if the charging phase ends with only a portion of the multiple SOC ranges being charged, the current rates for each of the remaining SOC ranges can be updated based on the update results for the current rates for some of the SOC ranges.

[0024] The effects of the present invention are not limited to the effects described above, and other effects of the present invention not mentioned will be clearly understood by those skilled in the art from the description of the claims.

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

[0026] [Figure 1] 1 is a diagram illustrating the configuration of an electric vehicle according to the present invention; [Diagram 2] 10 is a diagram illustrating an example of a correspondence relationship between a reference SOC range and a reference current recorded in a charging map. FIG. [Diagram 3] 10 is a diagram illustrating an example of a correspondence relationship between a reference SOC range and a reference voltage recorded in a charging map. FIG. [Figure 4] 2 is a flowchart illustrating a battery management method according to a first embodiment of the present invention. [Diagram 5] 5 is a flowchart illustrating a battery management method according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms and words used in the specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as having meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventor himself can appropriately define the concepts of terms in order to best describe the invention.

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

[0029] Terms including ordinal numbers such as "first", "second", etc. are used for the purpose of distinguishing one of various components from the rest, and are not intended to limit the components.

[0030] In addition, throughout the specification, when a part "includes" a certain element, this does not mean excluding other elements, but means that other elements may be further included, unless otherwise specified. Furthermore, terms such as "controller" in the specification refer to a unit that processes at least one function or operation, which may be embodied by hardware, software, or a combination of hardware and software.

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

[0032] FIG. 1 is a diagram illustrating the configuration of an electric vehicle according to the present invention.

[0033] Referring to FIG. 1 , an electric vehicle 1 includes a battery pack 10 , an inverter 30 , an electric motor 40 and a charging circuit 50 .

[0034] The battery pack 10 includes a battery B, a switch 20 and a battery management system 100.

[0035] The battery B includes at least one battery cell. The type of each battery cell is not particularly limited as long as it can be repeatedly charged and discharged, such as a lithium ion cell. The battery B may be coupled to the inverter 30 and / or the charging circuit 50 through a pair of power supply terminals provided on the battery pack 10.

[0036] The switch 20 is connected in series to the battery B. The switch 20 is provided in a current path for charging and discharging the battery B. The switch 20 is controlled to be turned on and off in response to a switching signal from the battery management system 100. The switch 20 may be a mechanical relay that is turned on and off by the magnetic force of a coil, or may be a semiconductor switch such as a metal oxide semiconductor field effect transistor (MOSFET).

[0037] The inverter 30 is provided to convert the direct current from the battery B to an alternating current in response to commands from the battery management system 100. The electric motor 40 may be, for example, a three-phase AC motor. The electric motor 40 is driven using the AC power from the inverter 30.

[0038] The battery management system 100 may be responsible for overall control related to charging and discharging of the battery B.

[0039] The battery management system 100 includes a sensing unit 110, a memory unit 120, and a control unit 140. The battery management system 100 may further include at least one of an interface unit 130 and a switch driver 150.

[0040] The sensing unit 110 includes a voltage sensor 111 and a current sensor 112. The sensing unit 110 may further include a temperature sensor 113.

[0041] The voltage sensor 111 is connected in parallel to the battery B and is configured to detect a battery voltage across the battery B and generate a voltage signal indicative of the detected battery voltage. The current sensor 112 is connected in series to the battery B through a current path. The current sensor 112 is configured to detect a battery current flowing through the battery B and generate a current signal indicative of the detected battery current. The temperature sensor 113 is configured to detect the temperature of the battery B and generate a temperature signal indicative of the detected temperature.

[0042] The memory unit 120 may include at least one type of storage medium, such as a flash memory type, a hard disk type, a solid state disk type (SSD type), a silicon disk drive type (SDD type), a multimedia card micro type, a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), and a programmable read-only memory (PROM). The memory unit 120 may store data and programs required for the calculation operation by the control unit 140. The memory unit 120 may store data indicating the result of the calculation operation by the control unit 140.

[0043] The memory unit 120 stores a charging map. The charging map may be stored in advance in the memory unit 120 before shipment of the battery management system 100, or may be received from an external source (e.g., a battery manufacturer) or the upper controller 2 via the interface unit 130.

[0044] The charging map is used for charging stages for multi-stage constant current charging of battery B. In the charging map, correspondence relationships between first to n-th reference SOC ranges, first to n-th reference currents, and first to n-th reference voltages for multi-stage constant current charging are recorded. n is a natural number of 2 or more. The lower-order reference current may be smaller than the higher-order reference current.

[0045] The interface unit 130 may include a communication circuit configured to support wired or wireless communication between the control unit 140 and the upper controller 2 (e.g., ECU: Electronic Control Unit). The wired communication may be, for example, CAN (controller area network) communication, and the wireless communication may be, for example, ZigBee (registered trademark) or Bluetooth (registered trademark) communication. Of course, the type of communication protocol is not particularly limited as long as it supports wired or wireless communication between the control unit 140 and the upper controller 2. The interface unit 130 may include an output device (e.g., a display, a speaker) that provides information received from the control unit 140 and / or the upper controller 2 in a form that can be recognized by a user. The upper controller 2 may control the inverter 30 based on battery information (e.g., voltage, current, temperature, SOC) collected through communication with the battery management system 100.

[0046] The control unit 140 may be operably coupled to the upper controller 2, the switch 20, the charging circuit 50, the sensing unit 110, the memory unit 120, the interface unit 130, and / or the switch driver 150. The fact that two components are operably coupled means that the two components are directly or indirectly connected to each other so as to be able to transmit and receive signals unidirectionally or bidirectionally.

[0047] The switch driver 150 is electrically coupled to the controller 140 and the switch 20. The switch driver 150 is configured to selectively turn the switch 20 on and off in response to commands from the controller 140. The controller 140 may instruct the switch driver 150 to turn on the switch 20 during the progress of a charging phase.

[0048] The control unit 140 may collect a sensing signal from the sensing unit 110. The sensing signal refers to a synchronously detected voltage signal, current signal, and / or temperature signal.

[0049] The control unit 140 may be implemented in hardware using at least one of an ASIC (application specific integrated circuit), a DSP (digital signal processor), a DSPD (digital signal processing device), a PLD (programmable logic device), an FPGA (field programmable gate array), a microprocessor, and other electrical units for performing functions.

[0050] The interface unit 130 may relay bidirectional communication between the control unit 140 and the charging circuit 50, and bidirectional communication between the control unit 140 and the upper controller 2. The charging circuit 50 may be configured to supply a charging current at a current rate requested by the battery management system 100 to the battery B. The charging circuit 50 may be configured to supply a charging voltage having a voltage level requested by the battery management system 100 to the battery B. The control unit 140 is configured to start a charging phase using a charging map in response to receiving a charging start command via the interface unit 130. The control unit 140 may end a charging phase using a charging map in response to receiving a charging interrupt command via the interface unit 130.

[0051] The control unit 140 may determine the SOC of the battery B based on the sensing signal. In determining the SOC, known algorithms such as an open circuit voltage (OCV)-SOC curve, ampere counting, a Kalman filter, etc. may be used.

[0052] Fig. 2 is a diagram illustrating a correspondence relationship between a reference SOC range and a reference current recorded in a charging map, and Fig. 3 is a diagram illustrating a correspondence relationship between a reference SOC range and a reference voltage recorded in a charging map. For convenience of explanation, Figs. 2 and 3 show that n=4, i.e., the charging map defines correspondence relationships between four reference SOC ranges, four reference currents, and four reference voltages.

[0053] The first current profile 210 shown in FIG. 2 indicates the correspondence relationship between the first to fourth reference SOC ranges ΔSOC1 to ΔSOC4 and the first to fourth reference currents I1 to I4 for a brand new battery B. The first current profile 210 may be recorded in a charging map in a format such as a data table. When k is a natural number equal to or smaller than n, S k is the kth reference SOC range ΔSOC k When m is a natural number less than n, S m is the m+1th reference SOC range ΔSOC m+1For example, S1 is the lower limit value of the second reference SOC range ΔSOC2 having S2 as its upper limit value. The lower limit value S0 of the first reference SOC range ΔSOC1 may be 0%.

[0054] The control unit 140 determines whether the SOC of the battery B is within the m-th reference SOC range ΔSOC m If the mth reference current I m may command the charging circuit 50 to charge at a constant current using

[0055] The control unit 140 determines the mth reference current I m During constant current charging using the m-th reference SOC range ΔSOC m Upper limit S m When the m+1 reference current I m+1 may command the charging circuit 50 to charge at a constant current using

[0056] The control unit 140 determines the n-th reference current I n During constant current charging using n Upper limit S n When the charging current reaches the predetermined threshold, constant voltage charging may be commanded to the charging circuit 50. This may terminate the multi-stage constant current charging using the charging map and switch to constant voltage charging.

[0057] The first voltage profile 310 shown in FIG. 3 indicates the correspondence relationship between the first to fourth reference SOC ranges ΔSOC1 to ΔSOC4 and the first to fourth reference voltages V1 to V4 for a brand new battery B. The first voltage profile 310 may be recorded in a charging map in a format such as a data table. k The SOC of the new battery B is the kth reference current I k The kth reference SOC range ΔSOC k Upper limit S k This is a predetermined reference voltage that indicates the battery voltage when it reaches

[0058] On the other hand, as mentioned above, as the battery B gradually degrades, the voltage rise with the same amount of charging current becomes faster than when the battery is new. This causes the k-th reference current I k During constant current charging using k The fact that battery B has reached V indicates that battery B has deteriorated compared to a new state. A second voltage profile 320 shown in FIG. 3 shows a change in battery voltage monitored during a process of constant current charging of deteriorated battery B using first to fourth reference currents I1 to I4 in sequence for first to fourth reference SOC ranges ΔSOC1 to ΔSOC4. Referring to second voltage profile 320, V 1k is the SOC of the degraded battery B within the k-th reference SOC range ΔSOC k Upper limit S k The battery voltage when the kth reference voltage V k It can be confirmed that V is greater than V. 11 >V1, V 12 >V2, V 13 >V3, V 14 >V4.

[0059] kth reference voltage V k is the kth reference current I k Since the constant current charging using k Within the k-th reference voltage V k Therefore, exceeding the k-th reference current I k During constant current charging using k When the k-th reference current I is reached, the magnitude of the charging current is increased to suppress the degradation of battery B. k It needs to be adjusted smaller than that.

[0060] The second current profile 220 shown in FIG. 2 and the third voltage profile 330 shown in FIG. 3 show time series of the battery current and battery voltage monitored during the process of charging a degraded battery B by applying the battery management method according to the present invention, i.e., the history of changes over time during charging.

[0061] Referring to the third voltage profile 330, the control unit 140 calculates the k-th reference current I k During constant current charging using the constant current charging method, the control unit 140 monitors the battery voltage, battery current, and battery SOC at set time intervals (for example, 0.001 seconds). k Upper limit S k If the battery voltage reaches the k-th reference voltage V k In response to the k-th reference current I k From the constant current charging using the kth reference voltage V k This allows the battery voltage to be switched to constant voltage charging using the k-th reference voltage V k When the SOC of battery B reaches the k-th reference SOC range ΔSOC k Upper limit S k Battery B will continue to charge the k-th reference voltage V until it reaches k With reference to the second current profile 220, the k-th reference voltage V k During constant voltage charging using, the battery current gradually decreases as the battery voltage gradually increases.

[0062] For example, constant current charging is performed using the second reference current I2 over the SOC range of S1 to Z2%, and then constant voltage charging is performed while the battery voltage of battery B is maintained equal to the second reference voltage V2 over the SOC range of Z2 to S2% (second constant voltage charging range). Also, it can be confirmed from the second current profile 220 that the battery current gradually decreases from the second reference current I2 during the constant voltage charging of battery B with the second reference voltage V2.

[0063] The control unit 140 may update a charging map including the first current profile 210 of FIG. 2 and the first voltage profile 310 of FIG. 3 based on the battery voltage and battery current monitored while the charging steps for at least one of the first to fourth reference SOC ranges ΔSOC1 to ΔSOC4 are sequentially performed.

[0064] Specifically, the control unit 140 determines whether the kth constant voltage charging range Z k ~S k The kth average current may be determined from a time series of the battery current monitored over a kth constant voltage charging period (which may be referred to as a "current history"), which is a charging period of the kth constant voltage charging period. The kth average current may be an average of the battery currents sensed repeatedly at set times during the kth constant voltage charging period. Thus, the kth average current may be calculated by multiplying the kth reference current I k Less than.

[0065] Next, the control unit 140 calculates the kth reference current I k The current I of the third current profile 230 of FIG. 11 ~I 14 may be the result of updating the reference currents I1 to I4 of the charging map, respectively.

[0066] The control unit 140 determines the k-th reference current I k For example, referring to FIG. 2, when the second reference current I2=120A and the second average current=100A, the second reference current I2 of 120A is updated to be equal to the kth average current I2 of 100A. 12 will be changed to.

[0067] Alternatively, the control unit 140 may set the kth reference current I k The kth reference current I is equal to the sum of the product of the kth average current and the first weighted value and the product of the kth average current and the second weighted value. kThe first weight value and the second weight value may each be a positive number less than 1, and the sum of the first weight value and the second weight value may be 1. For example, when the second reference current I2=120A, the second average current=100A, the first weight value=0.4, and the second weight value=0.6, the second reference current I2 of 120A may be updated in response to the smaller I2 of 108A. 12 and recorded in the charging map.

[0068] Meanwhile, the charging steps according to the above-mentioned battery management method are often terminated without being sequentially performed for each of the reference SOC ranges ΔSOC1 to ΔSOC4. For example, charging may be started before battery B is fully discharged, or the vehicle user may disconnect the charging cable from electric vehicle 1 before switching from constant current charging to constant voltage charging. In such cases, while it is possible to update the reference current corresponding to some of the reference SOC ranges for which the charging steps have been performed as described above, the reference current corresponding to the remaining reference SOC ranges may not be updated.

[0069] To solve the above problems, when charging is started when the SOC of battery B is greater than S0 or charging is terminated when the SOC of battery B is less than S4, the control unit 140 may update the reference current for each of the remaining reference SOC ranges based on update information for at least one of all reference SOC ranges ΔSOC1 to ΔSOC4.

[0070] kth reference SOC range ΔSOC k The kth reference current I k Only the battery management methods mentioned above allow 1k Assume that the control unit 140 has updated the I k I 1kAfter determining the ratio, the remaining reference currents may be updated based on the determined ratio. For example, if the second reference current I2 is updated from 120 A to 100 A, the control unit 140 may multiply the first reference current I1, the third reference current I3, and the fourth reference current I4 by 100 / 120=5 / 6, respectively, to update the first reference current I1, the third reference current I3, and the fourth reference current I4.

[0071] It is assumed that i and j are natural numbers, i≦j, i is 2 or more, and j is less than n. i ~ΔSOC j The i-th to j-th reference currents I i ~I j Only the battery management method (see Figure 4) i ~I j From I 1i ~I 1j The charging phase may end with each of the remaining reference currents updated to: Then, the controller 140 may update each of the remaining reference currents using the following equation:

number

[0072] In the above formula, x is a natural number equal to or less than n, excluding i to j, and I x is the reference current before the update, and I 1x is the updated reference current. μ avg is the i-th to j-th reference current I i ~I j The i-th to j-th updated reference currents I 1i ~I 1j is the average percentage of

[0073] For example, i=2, j=3, n=4, i1=150A, i2=120A, i 12 =100A, i3=110A, i 13 If i = 95A and i4 = 90A, then i 11 = i1 × 1 / 2 × {100 / 120 + 95 / 110}A ≒ 127A, and i 14= i4 × 1 / 2 × {100 / 120 + 95 / 110}A ≒ 76A.

[0074] FIG. 4 is a flowchart illustrating a battery management method according to a first embodiment of the present invention.

[0075] 1 to 4, in step S410, the control unit 140 sets the first to n-th reference SOC ranges ΔSOC1 to ΔSOC n and the first to nth reference currents I1 to I n and the first to nth reference voltages V1 to V n The charging maps 210 and 310 in which the correspondence between the charging conditions and the charging time is recorded are read from the memory unit 120.

[0076] In step S420, the control unit 140 calculates the first to n-th reference SOC ranges ΔSOC1 to ΔSOC n The k-th reference SOC range ΔSOC in which the SOC of battery B belongs k For example, when the SOC of battery B is equal to or greater than S1 and less than S2, the second reference SOC range ΔSOC2 is selected.

[0077] In step S430, the control unit 140 calculates the k-th reference SOC range ΔSOC k The kth reference current I k Constant current charging using

[0078] In step S440, the control unit 140 determines whether the SOC of the battery is within the k-th reference SOC range ΔSOC k Upper limit S k Before the battery voltage reaches the k-th reference SOC range ΔSOC k The kth reference voltage V k If the value of step S440 is "YES", proceed to step S450.

[0079] In step S450, the control unit 140 determines the k-th reference current I k From the constant current charging using the kth reference voltage V k Switch to constant voltage charging using

[0080] In step S460, the control unit 140 determines whether the SOC of the battery is within the k-th reference SOC range ΔSOC k Upper limit S k If the value of step S460 is "YES", proceed to step S470.

[0081] In step S470, the control unit 140 determines the k-th reference voltage V k The kth reference current I of the charging map is calculated based on the current history of the battery current over the charging period of the constant voltage charging using k Update the following.

[0082] In step S480, the control unit 140 calculates the k-th reference SOC range ΔSOC k is the nth reference SOC range ΔSOC n That is, the control unit 140 determines whether the SOC of the battery B is equal to or smaller than the maximum SOC S of the multi-stage constant current charging defined by the charging map. n has been reached. If the value of step S480 is "No", return to step S420. If the value of step S480 is "Yes", the method of FIG.

[0083] For reference, if a charging start command is received when the update condition is not satisfied, steps S440 to S470 may be omitted from the method of FIG.

[0084] The method of FIG. 4 can be started in response to a charging start command when a predetermined update condition is satisfied. The update condition is to prevent the charging maps 210 and 310 from being updated too frequently in vain. For example, it can be indicated that the degradation degree of the battery B has increased above a certain level, such as the accumulated capacity of the battery B has increased by more than a first critical value (for example, 100 Ah [ampere - hour]) compared to the accumulated capacity at the time of the previous update, the number of cycles of the battery B has increased by more than a second critical value (for example, 50 times) compared to the number of cycles at the time of the previous update, the capacity retention rate of the battery B has decreased by more than a third critical value (for example, 5%) compared to the capacity retention rate at the time of the previous update, and the result is more than a critical time (for example, one month) since the previous update time, etc.

[0085] FIG. 5 is a flowchart illustrating a battery management method according to a second embodiment of the present invention. The method of FIG. 5 can be used to update each of the remaining reference currents when only the i - th to j - th reference currents I n among the first to n - th reference currents I1 to I i ~I j are updated by the method of FIG. 4. That is, the method of FIG. 5 can be performed when the battery B is charged only for a part (for example, Z1 to S3 in FIG. 2) of the entire SOC range from S0 to S n as described above. As described above, i and j are each natural numbers, i < j, i is 2 or more, or j is less than n.

[0086] In step S510, the control unit 140 calculates the average ratio of the i - th to j - th updated reference currents I i ~I j for the i - th to j - th reference currents I 1i ~I 1j (refer to μ avg in the above formula).

[0087] In step S520, the control unit 140 determines the first to n - th reference currents I1 to I nAmong them, the i-th to j-th reference currents I i ~I j Each reference current, except for , is multiplied by the average ratio and each reference current is updated.

[0088] The embodiments of the present invention described above may not necessarily be embodied through an apparatus and method, but may be embodied through a program that realizes functions corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded, and such implementation should be easily embodied by a person skilled in the art to which the present invention pertains from the description of the above-mentioned embodiments.

[0089] Although the present invention has been described above with reference to limited embodiments and drawings, it goes without saying that the present invention is not limited thereto, and various modifications and variations can be made by those having ordinary skill in the art to which the present invention pertains within the scope of the technical spirit of the present invention and the scope of the claims.

[0090] Furthermore, since the above-mentioned invention can be variously replaced, modified, and altered by a person having ordinary knowledge in the technical field to which the invention belongs without departing from the technical concept of the invention, it is not limited to the above-mentioned embodiments and the attached drawings, and can be configured by selectively combining all or part of each embodiment to make various modifications.

Claims

1. a voltage sensor for measuring the battery voltage; a current sensor for measuring the battery current; a memory unit for storing a charging map in which a correspondence relationship between first to n-th reference SOC ranges and first to n-th reference currents for multi-stage constant current charging is recorded; a control unit that, in response to a charge start command, starts constant current charging using a k-th reference current corresponding to a k-th reference SOC range among the first to n-th reference SOC ranges to which the SOC of the battery belongs, and switches from the constant current charging to constant voltage charging using the k-th reference voltage in response to a battery voltage reaching a k-th reference voltage corresponding to the k-th reference SOC range before the SOC of the battery reaches an upper limit value of the k-th reference SOC range during the constant current charging, The control unit updates the k-th reference current of the charging map based on a current history of the battery current over a charging period of the constant voltage charging. Battery management system.

2. The control unit is 2. The battery management system according to claim 1, wherein, during the constant voltage charging, in response to the SOC of the battery reaching the upper limit value of the kth reference SOC range, the constant voltage charging is switched to constant current charging using a (k+1)th reference current corresponding to the (k+1)th reference SOC range.

3. The control unit is 2. The battery management system according to claim 1, wherein, during the constant voltage charging, in response to the SOC of the battery reaching the upper limit value of the kth reference SOC range, the kth reference current of the charging map is updated based on a current history of the battery current over a charging period of the constant voltage charging.

4. The control unit is determining an average current during the charging period based on the current history; The battery management system of claim 3 , wherein the kth reference current is updated to be equal to the average current.

5. The control unit is determining an average current during the charging period based on the current history; 4. The battery management system of claim 3, wherein the kth reference current is updated to be equal to a sum of a product of the kth reference current and a first weighted value and a product of the average current and a second weighted value.

6. The battery management system of claim 5 , wherein the first weight value and the second weight value are each a positive number less than 1, and a sum of the first weight value and the second weight value is 1.

7. The control unit is The battery management system of claim 3 , further comprising: updating each remaining reference current, except for the kth reference current, based on a ratio of the updated kth reference current to the kth reference current.

8. A battery pack comprising the battery management system according to any one of claims 1 to 7.

9. An electric vehicle comprising the battery pack of claim 8.

10. 1. A battery management method, comprising: reading out a charging map in which a correspondence relationship between first to n-th reference SOC ranges and first to n-th reference currents for multi-stage constant current charging is recorded in response to a charging start command; starting constant current charging using a k-th reference current corresponding to a k-th reference SOC range to which the SOC of the battery belongs among the first to n-th reference SOC ranges; during the constant current charging, in response to a battery voltage reaching a k-th reference voltage corresponding to the k-th reference SOC range before the SOC of the battery reaches an upper limit value of the k-th reference SOC range, switching from the constant current charging to constant voltage charging using the k-th reference voltage; updating a kth reference current of the charging map based on a current history of the battery over a charging period of the constant voltage charging. Battery management methods.

11. 11. The battery management method of claim 10, further comprising: switching from the constant voltage charging to constant current charging using a (k+1)th reference current corresponding to a (k+1)th reference SOC range in response to the SOC of the battery reaching the upper limit value of the kth reference SOC range during the constant voltage charging.

12. 11. The battery management method of claim 10, further comprising: updating the kth reference current of the charging map based on a current history of the battery over a charging period of the constant voltage charging in response to the SOC of the battery reaching the upper limit value of the kth reference SOC range during the constant voltage charging.

13. updating the kth reference current of the charging map, determining an average current during the charging period based on the current history; 13. The battery management method of claim 12, further comprising: updating the kth reference current to be equal to the average current.

14. determining a ratio between the kth reference current and the updated kth reference current; The battery management method of claim 12 , further comprising: updating each remaining reference current, except for the kth reference current, based on the ratio.

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