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

Abstract

To provide a battery management system, battery management method, and the like which 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 sensing unit 110 to generate a sensing signal indicating a battery voltage of a battery B; a memory unit 120 to store a charge map recording a correspondence between first to n-th reference currents and first to n-th reference voltage ranges for multi-stage constant-current charging; and a control unit 140 which, during progress of a charging stage using the charge map, commands a charging circuit 50 connected to the battery to perform constant-current charging using a k-th reference current corresponding to a k-th reference voltage range to which the battery voltage belongs. The control unit commands the charging circuit to perform constant-voltage charging using the upper limit of the k-th reference voltage range in response to the battery voltage reaching the upper limit of the k-th reference voltage 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. 10-2020-0104883, filed on August 20, 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 depending on the state of charge and voltage of the battery being charged. 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 the correspondence between a plurality of voltage ranges and a plurality of current rates is recorded. The charging stage using the multi-stage constant-current charging map is performed by repeating the process of supplying the charging current of the next current rate to the battery every time the battery voltage reaches the upper limit of each voltage range.

[0007] As a battery ages from its beginning of life (BOL), the same current rate can accelerate degradation. For example, constant current charging using the same current rate over a certain voltage range can induce more lithium deposition as the battery ages.

[0008] However, charging using a conventional multi-stage constant current charging map has the problem that it does not take into account the operating state (eg, degradation) of the battery that changes over time. [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 to match the operating state of the battery based on the voltage and current of the battery 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 a current rate for remaining voltage ranges in which constant current charging has not been performed based on an update result for a current rate for at least one voltage range in which constant current charging has been performed, even if the charging phase ends without being performed for all of a plurality of voltage ranges.

[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] A battery management system according to one aspect of the present invention includes a sensing unit that generates a sensing signal indicating a battery voltage of a battery, a memory unit that stores a charging map in which a correspondence between 1st to nth reference currents for multi-stage constant current charging and 1st to nth reference voltage ranges is recorded, and a control unit that commands a charging circuit connected to the battery to perform constant current charging using a kth reference current corresponding to a kth reference voltage range to which the battery voltage belongs during a charging stage using the charging map. The control unit is configured to command the charging circuit to perform constant voltage charging using the upper limit of the kth reference voltage range in response to the battery voltage reaching an upper limit of the kth reference voltage range. n is a natural number equal to or greater than 2, and k is a natural number equal to or less than n.

[0013] In response to the battery voltage reaching the upper limit of the kth reference voltage range, the control unit may update the charging map by comparing a kth measured voltage curve, which indicates the correspondence between the battery voltage and the battery SOC over the charging period of the constant current charging using the kth reference current, with a kth reference voltage curve.

[0014] The controller may update the kth reference current based on a ratio of an average SOC of the kth measured voltage curve to an average SOC of a kth reference voltage curve.

[0015] The controller may be configured to update the kth reference current based on a ratio of an average voltage of the kth reference voltage curve to an average voltage of the kth measurement voltage curve.

[0016] The control unit may be configured to update the kth reference current based on a first ratio of an average SOC of the kth measured voltage curve to an average SOC of the kth reference voltage curve and a second ratio of an average voltage of the kth reference voltage curve to an average voltage of the kth measured voltage curve.

[0017] The controller may be configured to update the kth reference current based on a ratio of a SOC of interest to a kth reference SOC, the SOC of the battery at a time when the battery voltage reaches an upper limit of the kth reference voltage range.

[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] The control unit may be configured to instruct the charging circuit to perform constant current charging using a k+1th reference current in response to the SOC of the battery reaching a kth reference SOC during the constant voltage charging using the upper limit of the kth reference voltage range.

[0020] A battery pack according to another aspect of the present invention includes the battery management system.

[0021] According to yet another aspect of the present invention, an electric vehicle includes the battery pack described above.

[0022] A battery management method according to still another aspect of the present invention includes the steps of: instructing a charging circuit connected to a battery to perform constant current charging using a k-th reference current corresponding to a k-th reference voltage range to which a battery voltage of the battery belongs, during a charging stage using a charging map in which a correspondence relationship between 1st to n-th reference currents and 1st to n-th reference voltage ranges for multi-stage constant current charging is recorded, and instructing the charging circuit to perform constant voltage charging using the upper limit of the k-th reference voltage range in response to the battery voltage reaching an upper limit of the k-th reference voltage range, where n is a natural number equal to or greater than 2 and k is a natural number equal to or less than n. The battery management method may further include a step of updating the charging map by comparing a kth measured voltage curve, which indicates a correspondence between the battery voltage and the battery SOC over a charging period of the constant current charging using the kth reference current, with a kth reference voltage curve in response to the battery voltage reaching an upper limit of the kth reference voltage range. The updating of the charge map may include updating the kth reference current based on a ratio of an average SOC of the kth measured voltage curve to an average SOC of the kth reference voltage curve. The battery management method may further include a step of instructing the charging circuit to perform constant current charging using a k+1th reference current in response to the SOC of the battery reaching a kth reference SOC during the constant voltage charging using an upper limit of the kth reference voltage range. Effect of the Invention

[0023] According to at least one embodiment of the present invention, the multi-stage constant current charging map can be updated to suit the operating condition of the battery based on the voltage and current of the battery monitored during charging using the multi-stage constant current charging map.

[0024] Furthermore, according to at least one embodiment of the present invention, even if the charging phase ends without being performed for the entirety of the multiple voltage ranges, the current rate for the remaining voltage ranges for which constant current charging has not been performed can be updated based on the update result for the current rate for at least one voltage range for which constant current charging has been performed.

[0025] 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.

[0026] 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]

[0027] [Figure 1] 1 is a diagram illustrating the configuration of an electric vehicle according to the present invention; [Diagram 2] FIG. 11 is a diagram illustrating a correspondence relationship between a reference current and a reference voltage range recorded in a charging map. [Diagram 3] 10 is a diagram illustrating an example of a correspondence relationship between a reference voltage range and a reference SOC 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

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] FIG. 1 is a diagram illustrating the configuration of an electric vehicle 1 according to the present invention.

[0034] 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 .

[0035] The battery pack 10 includes a battery B, a switch 20 and a battery management system 100.

[0036] 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.

[0037] 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).

[0038] 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.

[0039] The battery management system 100 may be responsible for overall control related to charging and discharging of the battery B.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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. Data recorded in the charging map may be predetermined based on test and / or simulation results for a battery sample having the same specifications as battery B.

[0045] The charging map is used for charging stages for multi-stage constant current charging of battery B. In the charging map, correspondences between (i) first to n-th reference currents, (ii) first to n-th reference voltage ranges, (iii) first to n-th reference SOCs, and (iv) first to n-th reference voltage curves for multi-stage constant current charging are recorded. n is a natural number of 2 or more. The later-order reference current may be smaller than the earlier-order reference current. Each reference voltage range may be referred to as a "stage."

[0046] 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. The upper controller 2 may transmit a charging start command or a charging interrupt command to the battery management system 100 in response to an input from a vehicle user.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] The control unit 140 is also called a "battery controller" and 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.

[0051] 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.

[0052] The control unit 140 may determine a state of charge (SOC) indicating the remaining capacity of the battery B based on the sensing signal. In determining the SOC, known algorithms such as ampere counting, an open circuit voltage (OCV)-SOC curve, a Kalman filter, etc. may be used. The SOC of the battery B may be referred to as the "battery SOC."

[0053] Fig. 2 is a diagram illustrating a correspondence relationship between a reference current and a reference voltage range recorded in a charging map, and Fig. 3 is a diagram illustrating a correspondence relationship between a reference voltage range and a reference SOC 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 currents, four reference voltage ranges, and four reference SOCs.

[0054] The current profile 210 shown in FIG. 2 indicates the correspondence relationship between the first to fourth reference currents I1 to I4 and the first to fourth reference voltage ranges ΔV1 to ΔV4 for a brand new battery B. The current profile 210 may be recorded in a charging map in a format such as a data table. When k (which may be referred to as a "charging index") is a natural number equal to or less than n, V k-1 and V k Each of the kth reference voltage ranges ΔV kare the lower and upper limits.

[0055] The first to fourth reference voltage ranges ΔV1 to ΔV4 are successive. i is the i-th reference voltage range ΔV i and the upper limit of the (i+1)th reference voltage range ΔV i+1 For example, the upper limit of ΔV2 and the lower limit of ΔV3 are each equal to V2. k may be referred to as the "kth reference voltage."

[0056] The control unit 140 determines whether the battery voltage of the battery B is within the i-th reference voltage range ΔV i If it is within the i-th reference current I i may command the charging circuit 50 to charge at a constant current using

[0057] The control unit 140 calculates the i-th reference current I i During constant current charging using i The upper limit of V i When the i+1th reference current I i+1 That is, the control unit 140 can instruct the charging circuit 50 to perform constant current charging using the i-th reference current I i From the constant current charging using the (i+1)th reference current I i+1 3. The charging current can be switched to constant current charging using

[0058] The control unit 140 determines the n-th reference current I n During constant current charging using n The upper limit of V n When the upper limit V n That is, the control unit 140 can instruct the charging circuit 50 to perform constant voltage charging using the nth reference current I n From constant current charging using the upper limit V n It is possible to switch to constant voltage charging using

[0059] The first voltage profile 310 shown in FIG. 3 indicates the correspondence relationship between the first to fourth reference SOCs S1 to S4 and the first to fourth reference voltage ranges ΔV1 to ΔV4 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. The first voltage profile 310 includes first to fourth reference voltage curves. The kth reference voltage curve is a kth reference voltage range ΔV k This is the part that corresponds to.

[0060] S k is the battery voltage of a brand new battery B at the kth reference current I k The k-th reference voltage V k This indicates the SOC of battery B when it reaches

[0061] On the other hand, as the battery B gradually degrades, the capacity loss of the battery B increases, and the voltage rise with the same charge capacity increases compared to when the battery is new. This causes the k-th reference current I k During constant current charging using k If the battery voltage reaches the k-th reference voltage V k The fact that the battery B has reached Z indicates that the battery B has deteriorated compared to a new state. The second voltage profile 320 shown in FIG. 3 shows the correspondence relationship between the history of changes in the battery voltage and the history of changes in the SOC, which are monitored during the process of constant current charging of the deteriorated battery B using the first to fourth reference currents I1 to I4 in sequence for the first to fourth reference voltage ranges ΔV1 to ΔV4 without applying the battery management method (see FIG. 4) according to the present invention. Referring to the second voltage profile 320, Z k The battery voltage of the degenerated battery B is the kth reference voltage V k The battery SOC when the k-th reference SOC S k It can be verified that S1>Z1, S2>Z2, S3>Z3, and S4>Z4 are all smaller than Z1, S2, S3, and Z4.

[0062] kth reference current Ik During constant current charging using k If the battery voltage reaches the k-th reference voltage V k The kth reference current I k This indicates that the kth reference current I k The k-th reference current I k The degree of reduction can be determined.

[0063] The third voltage profile 330 shown in FIG. 3 shows a correspondence relationship between a change history of the battery voltage and a change history of the SOC, which are monitored during the process of charging a degraded battery B by applying the battery management method according to the present invention (see FIG. 4). The third voltage profile 330 includes first to fourth measured voltage curves. The k-th measured voltage curve is a k-th reference voltage range ΔV k This is the part that corresponds to.

[0064] 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 battery voltage, battery current and SOC are monitored at set time intervals (for example, 0.001 seconds). The control unit 140 determines whether the SOC of the battery B is equal to or lower than the k-th reference SOC 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 S k Battery B will continue to charge the k-th reference voltage V until it reaches kFor example, after constant current charging using the second reference current I2 is performed over the voltage range from V1 to V2, the battery B is charged at a constant voltage with a charging voltage equal to the k-th reference voltage V2 until the SOC of the battery B reaches the second reference SOC S2. k During constant voltage charging using the kth reference voltage range ΔV, the battery current gradually decreases as the battery voltage gradually increases. k During constant voltage charging using the above method, the battery voltage, battery current and SOC can be monitored at set time intervals.

[0065] The control unit 140 determines the k-th reference voltage range ΔV k Based on the battery voltage, battery current, and SOC monitored during charging over a period of time, the kth reference current I k The current I of the 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] Specifically, the controller 140 may determine at least one of the average voltage and the average SOC of the k-th reference voltage curve. The average voltage of the k-th reference voltage curve is determined by the k-th reference voltage range ΔV k The average SOC of the k-th reference voltage curve is the average of the battery voltage over the k-th reference voltage range ΔV k The SOC is the average over the period.

[0067] The control unit 140 may determine at least one of the average voltage and the average SOC of the k-th measured voltage curve. The average voltage of the k-th measured voltage curve is within the k-th reference voltage range ΔV k The average SOC of the k-th measured voltage curve is the average of the battery voltage over the k-th reference voltage range ΔV k The SOC is the average over the period.

[0068] Thereafter, the control unit 140 calculates the kth reference current I of the charging map based on at least one of the average voltage and the average SOC of the kth reference voltage curve and at least one of the average voltage and the average SOC of the kth measurement voltage curve. k may be updated.

[0069] The control unit 140 calculates the kth reference current I based on a first ratio (less than 1) of the average SOC of the kth measured voltage curve to the average SOC of the kth reference voltage curve. k For example, the control unit 140 may update the first ratio and the k-th reference current I k The kth reference current I k may be updated.

[0070] Alternatively, the control unit 140 may calculate the kth reference current I based on a second ratio (which is less than 1) of the average voltage of the kth reference voltage curve to the average voltage of the kth measurement voltage curve. k For example, the control unit 140 may update the second ratio and the k-th reference current I k The kth reference current I k may be updated.

[0071] Alternatively, the control unit 140 may determine the k-th reference current I k For example, the control unit 140 may update the first ratio, the second ratio, and the k-th reference current I k The kth reference current I k may be updated.

[0072] Alternatively, the control unit 140 may set the kth reference SOC S k Based on the third percentage of the SOC of interest (which is less than 1), the kth reference current I k For example, the control unit 140 may update the third ratio and the k-th reference current I k The kth reference current I k The SOC of interest is the battery voltage V kSOC of battery B at the time of reaching U k may be identical to

[0073] Meanwhile, the charging stage according to the above-mentioned battery management method is often not performed for some of the reference voltage ranges ΔV1 to ΔV4. For example, referring to Figs. 2 and 3, if the charging stage using the charging map is started when the battery voltage is higher than V0, the first measured voltage curve over the entire first reference voltage range ΔV1 cannot be obtained, and therefore the first reference current I1 cannot be updated in the above-mentioned method. As another example, if the vehicle user disconnects the charging cable from the electric vehicle 1 before the battery voltage reaches V4, the fourth measured voltage curve over the entire fourth reference voltage range ΔV4 cannot be obtained, and therefore the fourth reference current I4 cannot be updated.

[0074] To solve the above problem, when charging is started when the battery voltage is greater than V0 or charging is terminated when the battery voltage is less than V4, the control unit 140 may update the reference current for each of the remaining reference voltage ranges based on update information for at least one reference voltage range for which a measurement voltage curve has been obtained among all the reference voltage ranges ΔV1 to ΔV4.

[0075] kth reference voltage range ΔV 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 1k After determining the ratio, the control unit 140 may update each of the remaining reference currents based on the determined ratio. For example, when 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.

[0076] Assume that i and j are natural numbers, i≦j, i is 2 or more, and j is less than n=4. i ~ΔV j The i-th to j-th reference currents I i ~I j Only the battery management method (see Figure 4) 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: <Formula>

number

[0077] 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

[0078] In one example, i=2, j=3, n=4, i1=150A, i2=120A, i3=110A, i4=90A, i 12 = 100A, i 13 If = 95A, then i 11 =i1×1 / (3-2+1)×{i 12 / i2+i 13 / i3}A=i1×1 / 2×{100 / 120+95 / 110}A≒127A, and i 14 =i4×1 / (3-2+1)×{i 12 / i2+i 13 / i3}A=i4×1 / 2×{100 / 120+95 / 110}A≒76A.

[0079] 4 is a flow chart illustrating a battery management method according to a first embodiment of the present invention. The method of FIG. 4 can be started in response to a charge start command from a vehicle user.

[0080] 1 to 4, in step S410, the control unit 140 determines whether the battery voltage of the battery B falls within the k-th reference voltage range ΔV k The kth reference current I k from the charging map. For example, when the battery voltage is equal to or greater than V1 and less than V2, the second reference current I2 is selected.

[0081] In step S420, the control unit 140 determines the k-th reference current I k This causes the charging circuit 50 to perform constant current charging using the k-th reference current I k is supplied to battery B as a charging current, k Constant current charging using

[0082] In step S430, the control unit 140 determines whether the battery SOC is equal to the kth reference SOC S k If the battery voltage reaches the k-th reference voltage V k If the value of step S440 is "yes", proceed to step S450. If the value of step S430 is "no", after a predetermined time, step S430 is again performed.

[0083] In step S440, the control unit 140 supplies the k-th reference voltage V k This causes the charging circuit 50 to charge with the kth reference current I k and terminate the constant current charging using the kth reference voltage V k Supply the same charging voltage to battery B.

[0084] In step S450, the control unit 140 determines whether the battery SOC is a k-th reference SOC S kIf the value of step S450 is "yes", proceed to step S460. If the value of step S450 is "no", step S450 is again performed after a predetermined time.

[0085] In step S460, the control unit 140 determines a k-th measurement voltage curve. The k-th measurement voltage curve is a k-th reference current I k 1 shows the relationship between battery voltage and battery SOC over the charging period for constant current charging using

[0086] In step S470, the control unit 140 determines whether the voltage range of the k-th measurement voltage curve is within the k-th reference voltage range ΔV k If the value of step S470 is "yes", proceed to step S480. If the value of step S470 is "no", proceed to step S490. For example, if the battery has been charged at a constant current with the first reference current I1 since the battery voltage was greater than V0 and less than V1, the value of step S470 is "no".

[0087] In step S480, the control unit 140 updates the charging map based on the kth reference voltage curve and the kth measured voltage curve.

[0088] In step S490, the control unit 140 determines whether the charging index k is equal to n. That is, the control unit 140 determines whether the charging index k is equal to n. n 4 is completed. If the value of step S490 is "No", in step S492, the charging index k is increased by 1, and then the method returns to step S430. If the value of step S490 is "Yes", the method of FIG. 4 ends.

[0089] 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 for preventing 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 to a certain level or more, 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.

[0090] 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 of the voltage range from V0 to V n . As described above, i and j are natural numbers respectively, i < j, i is 2 or more, or j is less than n (for example, 4).

[0091] 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).

[0092] In step S520, the control unit 140 calculates the first to n - th reference currents I1 to I nAmong them, the i-th to j-th reference currents I i ~I j The remaining reference currents excluding the current 1 are each multiplied by the average ratio, and the remaining reference currents are each updated.

[0093] 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.

[0094] 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.

[0095] 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 sensing unit that generates a sensing signal indicative of a battery voltage of the battery; a memory unit for storing a charging map in which a correspondence relationship between first to nth reference currents for multi-stage constant current charging and first to nth reference voltage ranges is recorded; a control unit that commands a constant current charging using a k-th reference current corresponding to a k-th reference voltage range in which the battery voltage belongs to a charging circuit connected to the battery during a charging stage using the charging map; The control unit is In response to the battery voltage reaching an upper limit of the kth reference voltage range, command the charging circuit to perform constant voltage charging using the upper limit of the kth reference voltage range; n is a natural number equal to or greater than 2, k is a natural number equal to or less than n, The control unit is A kth measured voltage curve, which indicates a correspondence relationship between a battery voltage and a battery SOC during a charging period of the constant current charging using the kth reference current, is compared with a kth reference voltage curve to update the charging map. Battery management system.

2. The control unit is The battery management system of claim 1 , wherein the kth reference current is updated based on a ratio of an average SOC of the kth measured voltage curve to an average SOC of the kth reference voltage curve.

3. The control unit is The battery management system of claim 1 , further comprising: updating the kth reference current based on a ratio of an average voltage of the kth reference voltage curve to an average voltage of the kth measured voltage curve.

4. The control unit is 2. The battery management system of claim 1, wherein the kth reference current is updated based on a first ratio of an average SOC of the kth measured voltage curve to an average SOC of the kth reference voltage curve and a second ratio of an average voltage of the kth reference voltage curve to an average voltage of the kth measured voltage curve.

5. The control unit is updating the k-th reference current based on a ratio of the SOC of interest to the k-th reference SOC; The battery management system of claim 1 , wherein the SOC of interest is the SOC of the battery at a time when the battery voltage reaches an upper limit of the kth reference voltage range.

6. The control unit is The battery management system of claim 1 , 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.

7. The control unit is 2. The battery management system of claim 1, wherein during the constant voltage charging using the upper limit of the kth reference voltage range, in response to the SOC of the battery reaching the kth reference SOC, the battery management system commands the charging circuit to perform constant current charging using a k+1th 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. commanding a charging circuit connected to the battery to perform constant current charging using a k-th reference current corresponding to a k-th reference voltage range to which a battery voltage of the battery belongs, during a charging stage using a charging map in which a correspondence relationship between first to n-th reference currents and first to n-th reference voltage ranges for multi-stage constant current charging is recorded; instructing the charging circuit to perform constant voltage charging using the upper limit of the kth reference voltage range in response to the battery voltage reaching the upper limit of the kth reference voltage range; and updating the charging map by comparing a k-th measured voltage curve, which indicates a correspondence relationship between the battery voltage and the SOC of the battery over a charging period of the constant current charging using the k-th reference current, with a k-th reference voltage curve; A battery management method, wherein n is a natural number equal to or greater than 2, and k is a natural number equal to or less than n.

11. The step of updating the charging map includes: The battery management method of claim 10 , further comprising updating the kth reference current based on a ratio of an average SOC of the kth measured voltage curve to an average SOC of the kth reference voltage curve.

12. 11. The battery management method of claim 10, further comprising the step of instructing the charging circuit to perform constant current charging using a k+1th reference current in response to the SOC of the battery reaching a kth reference SOC during the constant voltage charging using the upper limit of the kth reference voltage range.

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