Battery management system and method, and battery pack including same

Abstract

The present invention relates to a battery management system and method capable of accurately measuring the characteristics of battery cells, and a battery pack including the same. A battery pack according to one embodiment of the present invention includes a battery module including a plurality of battery cells, at least one reference cell having a greater number of electrodes than the battery cells, and a battery management system that controls the battery cells and the reference cell, wherein the battery management system measures a first voltage of the battery cells and a second voltage of the reference cell, and is capable of determining the state of the battery module based on the deviation between the first voltage and the second voltage.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0125848, filed September 30, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery management system and method, and a battery pack including the same, and more particularly to a battery management system and method that can accurately measure the characteristics of battery cells, and a battery pack including the same. [Background technology]

[0003] In recent years, the demand for portable electronic products such as laptops, video cameras, and mobile phones has increased dramatically, and as the development of electric vehicles, energy storage batteries, robots, satellites, and other devices has progressed in earnest, much research has been conducted on secondary batteries used as the driving power source for these products.

[0004] The secondary battery is used as a battery pack including a battery module in which a plurality of battery cells are connected in series and / or parallel. The state and operation of the battery pack are managed and controlled by a battery management system.

[0005] The battery management system measures the electrical characteristics of the battery cells and can determine the battery state based on the measured characteristics. However, if the electrical characteristics of the battery cells cannot be accurately measured, the battery state cannot be accurately determined. Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the embodiments of the present invention is to provide a battery management system and method capable of accurately measuring the characteristics of a battery cell, and a battery pack including the same.

[0007] The technical problems of the present invention are not limited to those mentioned above, and other technical problems not mentioned will be apparent to those skilled in the art from the following description. [Means for solving the problem]

[0008] A battery pack according to one embodiment of the present invention includes a battery module including a plurality of battery cells, at least one reference cell having a greater number of electrodes than the battery cells, and a battery management system that controls the battery cells and the reference cell, wherein the battery management system measures a first voltage of the battery cells, measures a second voltage of the reference cell, and determines the state of the battery module based on the deviation between the first voltage and the second voltage.

[0009] According to one embodiment, each of the plurality of battery cells may include a first negative electrode and a first positive electrode, and the reference cell may include a second negative electrode, a second positive electrode, and a reference electrode.

[0010] According to one embodiment, the first voltage may be a first negative electrode voltage of the battery cell, and the second voltage may be a second negative electrode voltage corresponding to a potential difference between a reference electrode of the reference cell and the second negative electrode.

[0011] According to one embodiment, the battery management system may measure the first negative electrode voltage while charging the battery cell, and measure the second negative electrode voltage while charging the reference cell.

[0012] According to one embodiment, the first voltage may be a first cell voltage corresponding to a potential difference between the first positive electrode and the first negative electrode, the second voltage may be a second cell voltage corresponding to a difference between a second positive electrode voltage and a second negative electrode voltage, the second positive electrode voltage may be a potential difference between the reference electrode and the second positive electrode, and the second negative electrode voltage may be a potential difference between the reference electrode and the second negative electrode.

[0013] According to one embodiment, the battery management system can measure the first cell voltage while charging the battery cell, and measure the second cell voltage while charging the reference cell.

[0014] According to one embodiment, the battery management system can estimate a state of health (SOH) of the battery module based on a deviation between the first voltage and the second voltage, and determine the state of the plurality of battery cells based on the estimated SOH.

[0015] According to one embodiment, the battery management system can correct a first voltage based on a deviation between the first voltage and the second voltage, estimate a state of health (SOH) of the battery module based on the corrected first voltage, and determine the state of the plurality of battery cells based on the estimated SOH.

[0016] A battery management system according to one embodiment of the present invention may include a measurement unit that measures first voltages of a plurality of battery cells included in a battery module and measures second voltages of at least one reference cell having a greater number of electrodes than the battery cells, and a control unit that determines the state of the plurality of battery cells based on a deviation between the first voltage and the second voltage.

[0017] According to one embodiment, the measurement unit can measure the first voltage while charging the battery cell including a first negative electrode and a first positive electrode, and measure the second voltage while charging the reference cell including a second negative electrode, a second positive electrode, and a reference electrode.

[0018] A battery management method according to one embodiment of the present invention may include the steps of measuring a first voltage of a plurality of battery cells included in a battery module, measuring a second voltage of at least one reference cell having a greater number of electrodes than the battery cells, and determining the state of the plurality of battery cells based on a deviation between the first voltage and the second voltage. [Effects of the Invention]

[0019] According to an embodiment of the present invention, the electrical characteristics (e.g., negative electrode voltage and cell voltage) of a battery cell can be accurately measured through the reference electrode included in the reference cell. According to an embodiment of the present invention, the SOH of a battery cell can be accurately determined from at least one of the negative electrode voltage and the cell voltage.

[0020] According to the embodiment of the present invention, the SOH of the battery cells can be accurately determined, and therefore cell balancing can be performed. In addition, this document can provide various other benefits that can be perceived directly or indirectly. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a block diagram showing a battery pack according to an embodiment of the present invention; [Figure 2] 2 is a perspective view showing a battery cell included in the battery module shown in FIG. 1. FIG. [Figure 3] FIG. 2 is a plan view showing a reference cell included in the battery pack shown in FIG. [Figure 4] FIG. 2 is a detailed block diagram of the battery management system shown in FIG. 1. [Figure 5] 3 is a flowchart showing a battery management method according to the first embodiment of the present invention. [Figure 6] 4 is a graph showing the negative electrode voltage depending on the SOC change of the battery cell according to the first embodiment of the present invention and a reference cell. [Figure 7] 6 is a flowchart showing a battery management method according to a second embodiment of the present invention. [Figure 8] 10 is a graph showing cell voltages depending on changes in SOC of a battery cell according to a second embodiment of the present invention and a reference cell. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily understand and practice the preferred embodiments of the present invention. However, the present invention may be embodied in various different forms and is not limited to the following embodiments.

[0023] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that may unnecessarily obscure the gist of the present invention will be omitted, and in this specification, when assigning reference symbols to components in each drawing, the same or similar reference symbols will be assigned to the same or similar components throughout the specification.

[0024] Furthermore, the terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, based on the principle that inventors can appropriately define the concepts of terms in order to best explain their inventions.

[0025] FIG. 1 is a block diagram showing a battery pack according to an embodiment of the present invention, FIG. 2 is a perspective view showing a battery cell included in the battery module shown in FIG. 1, and FIG. 3 is a plan view showing a reference cell included in the battery pack shown in FIG. 1.

[0026] 1 to 3, a battery pack 110 may include a reference cell 200, a battery module 130, and a battery management system 120. Each of the plurality of battery modules 130 may be formed in a stack form in which a plurality of battery cells 100 are stacked. Each of the plurality of battery cells 100 may be formed in a two-electrode structure including a first positive electrode (or working electrode) 101 and a first negative electrode (or counter electrode) 102, as shown in FIG.

[0027] At least one reference cell 200 may be provided. The reference cell 200 may be formed with a greater number of electrodes than the battery cell 100. The reference cell 200 may be formed in a three-electrode structure including a second positive electrode 201, a second negative electrode 202, and a reference electrode 203.

[0028] The reference electrode 203 can be used as a potential reference when measuring the relative value of the electrode potential. Because a current flows between the second positive electrode 201 and the second negative electrode 202 and almost no current flows through the reference electrode 203, the potential of the reference electrode 203 itself does not change. When measuring the second negative electrode voltage, which corresponds to the potential difference between the reference electrode 203 and the second negative electrode 202 of the reference cell 200, the potential of the reference electrode 203 does not change, allowing for accurate measurement of the second negative electrode voltage. When measuring the second positive electrode voltage, which corresponds to the potential difference between the reference electrode 203 and the second positive electrode 201 of the reference cell 200, the potential of the reference electrode 203 itself does not change, allowing for accurate measurement of the second positive electrode voltage.

[0029] The battery management system 120 is an interface that receives input of measured values ​​of various parameters, and may include a plurality of terminals and circuits connected to these terminals for processing the received values.

[0030] The battery management system 120 monitors the voltage, current, temperature, etc. of each of the battery cells 100 and the reference cells 200 included in the battery module 130, and can control and manage the battery cells 100 to prevent overcharging and over-discharging, etc.

[0031] FIG. 4 is a detailed block diagram of the battery management system shown in FIG. Referring to FIG. 4, the battery management system 120 may include a measurement unit 121, a control unit 122, and a storage unit 123.

[0032] The measurement unit 121 can measure a first voltage of a battery cell (for example, the battery cell 100 in FIG. 2) and measure a second voltage of a reference cell (for example, the reference cell 200 in FIG. 3).

[0033] The measuring unit 121 can measure a first negative electrode voltage (or a first voltage) of the battery cell while charging the battery cell. The measuring unit 121 can measure the first negative electrode voltage corresponding to the difference between the potential of the first negative electrode of the battery cell and a reference potential (e.g., 0 V). The measuring unit 121 can measure a second negative electrode voltage (or a second voltage) corresponding to the potential difference between the reference electrode and the second negative electrode of the reference cell while charging the reference cell. The measurement unit 121 can measure the first negative electrode voltage of the battery cell in an open state and measure the second negative electrode voltage of the reference cell in an open state.

[0034] The control unit 122 may be configured to calculate a deviation between a first negative electrode voltage of the battery cell and a second negative electrode voltage of a reference cell. The control unit 122 may be communicably connected to the measurement unit 121 via a wire and / or a wireless connection. The control unit 122 may receive the first negative electrode voltage and the second negative electrode voltage from the measurement unit 121 and calculate a voltage deviation between the received first negative electrode voltage and the second negative electrode voltage.

[0035] For example, the control unit 122 can accurately correct the first negative electrode voltage based on the voltage deviation between the first negative electrode voltage and the second negative electrode voltage. When a current flows between the first positive electrode and the first negative electrode of a battery cell, if the first positive electrode potential fluctuates, the first negative electrode potential also fluctuates, making it difficult to accurately measure the first negative electrode voltage. In contrast, a reference cell including a reference electrode can measure the second negative electrode voltage more accurately than a battery cell. Thus, the control unit 122 can accurately calculate the first negative electrode voltage by correcting the first negative electrode voltage based on the deviation between the first negative electrode voltage and the second negative electrode voltage measured via the measurement unit. The control unit 122 can estimate the SOH (state of health) of the battery module and the battery pack including the battery cell based on the corrected first negative electrode voltage. The control unit 122 can estimate the SOH of the battery module and the battery pack based on data regarding the correlation between the first negative electrode voltage and the SOH measured in advance. The data on the correlation between the corrected first negative electrode voltage and the SOH may be stored in advance in the storage unit 123. The data on the correlation between the corrected first negative electrode voltage and the SOH may be a value obtained in advance by at least one prior estimation. The data on the correlation between the corrected first negative electrode voltage and the SOH may be re-estimated at regular intervals and periodically updated in the storage unit 123.

[0036] As another example, the control unit 122 may estimate the state of health (SOH) of a battery module and a battery pack including a battery cell based on a voltage deviation between a first negative electrode voltage and a second negative electrode voltage. The control unit 122 may estimate the SOH of the battery module and the battery pack based on data relating to the correlation between the SOH and a voltage deviation between negative electrode voltages measured in advance. The data relating to the correlation between the SOH and a voltage deviation between the negative electrode voltages of a battery cell and a reference cell may be stored in advance in the storage unit 123. The data relating to the correlation between the SOH and a deviation between the negative electrode voltages of a battery cell and a reference cell may be a value obtained in advance by at least one prior estimation. The data relating to the correlation between the SOH and a deviation between the negative electrode voltages of a battery cell and a reference cell may be periodically re-estimated and periodically updated in the storage unit 123.

[0037] The control unit 122 can determine the state of the battery module and battery pack including the battery cells based on the estimated SOH. The control unit 122 can predict the degree of deterioration, replacement time, and lifespan of the battery cells based on the estimated SOH. The control unit 122 can also select battery cells to be balanced based on the SOH of each of the multiple battery cells. For example, the control unit 122 can compare the SOH of each of the multiple battery cells and select battery cells whose SOH falls outside a threshold as balancing targets. The control unit 122 can perform balancing on the battery cells selected as balancing targets. This allows the battery module and battery pack including the battery cells to be safely managed.

[0038] FIG. 5 is a flowchart showing a battery management method according to the first embodiment of the present invention. In operation S11, a measurement unit (e.g., the measurement unit 121 in FIG. 4) may measure a voltage (or a first voltage) of a first negative electrode (e.g., the first negative electrode 102 in FIG. 2) of a battery cell (e.g., the battery cell 100 in FIG. 2) while charging the battery cell. The first negative electrode voltage may correspond to a difference between the potential of the first negative electrode of the battery cell and a reference potential (e.g., 0 V).

[0039] Meanwhile, as the battery cell is charged, the first negative electrode voltage of the battery cell may decrease due to an electrochemical phenomenon inside the battery cell. If the battery cell is continuously charged when the negative electrode potential of the battery cell is low (e.g., below 0 V), metal plating may occur on the negative electrode, shortening the life of the battery cell. Therefore, in the present invention, the first negative electrode voltage of the battery cell may be measured so that the negative electrode potential of the battery cell is greater than the reference potential during the charging process of the battery cell.

[0040] In operation S12, the measurement unit may measure a second negative electrode voltage (or a second voltage) of the reference cell (e.g., reference cell 200 in FIG. 3) while charging the reference cell. The second negative electrode voltage may correspond to a potential difference between a reference electrode (e.g., reference electrode 203 in FIG. 3) and a second negative electrode (e.g., second negative electrode 202 in FIG. 3) of the reference cell.

[0041] In operation S13, the control unit (e.g., the control unit 122 in FIG. 4) calculates the voltage deviation between the first negative electrode voltage of the battery cell and the second negative electrode voltage of the reference cell, corrects the first negative electrode voltage based on the calculated voltage deviation, and can estimate the SOH (state of health) of the battery module and battery pack including the battery cell based on the corrected first negative electrode voltage.

[0042] As another example, the control unit can calculate a voltage deviation between the first negative electrode voltage of the battery cell and the second negative electrode voltage of the reference cell, and estimate the SOH (state of health) of the battery module and battery pack including the battery cell based on the calculated voltage deviation.

[0043] The control unit can predict the deterioration level, replacement time, and lifespan of the battery cell based on the estimated SOH. In addition, the control unit can control charging of the battery pack so that the first negative electrode voltage of the battery cell measured (or corrected) via the measurement unit is maintained at a certain level or higher (or so that it is greater than the reference potential). This can improve the lifespan characteristics of the battery pack.

[0044] 6 is a graph showing the negative electrode voltage depending on the SOC of each of the battery cell according to the first embodiment of the present invention and a reference cell. In FIG. 6, the horizontal axis represents the SOC (state of charge) (or remaining capacity) of the battery, and the vertical axis represents the negative electrode voltage of each of the battery cell and the reference cell. An SOC of 0 means that the negative electrode voltage has reached a predetermined upper limit voltage and is in a fully discharged state, and an SOC greater than 0 means that the negative electrode voltage has reached a predetermined lower limit voltage and is approaching a fully charged state.

[0045] Referring to FIG. 6, the control unit (e.g., the control unit 122 in FIG. 4) may generate a first anode voltage profile 501 in which the first anode voltage gradually decreases as the SOC of the battery cell increases (or the amount of lithium ions stored in the battery cell increases). The control unit may generate a second anode voltage profile 502 in which the second anode voltage gradually decreases as the SOC of the reference cell increases (or the amount of lithium ions stored in the reference cell increases). The first anode voltage profile 501 and the second anode voltage profile 502 may be generated by a charging experiment on the battery cell and the reference cell. The control unit may calculate a voltage deviation between the first anode voltage and the second anode voltage based on the first anode voltage profile 501 and the second anode voltage profile 502. The control unit may estimate the state of health (SOH) of the battery cell based on the calculated voltage deviation.

[0046] FIG. 7 is a flowchart showing a battery management method according to a second embodiment of the present invention. In operation S21, a measurement unit (e.g., the measurement unit 121 in FIG. 4) may measure a first cell voltage (or a first voltage) of a battery cell (e.g., the battery cell 100 in FIG. 2) while charging the battery cell. The first cell voltage may be a voltage corresponding to a potential difference between a first positive electrode (e.g., the first positive electrode 101 in FIG. 2) and a first negative electrode (e.g., the first negative electrode 102 in FIG. 2) of the battery cell.

[0047] In operation S22, the measurement unit may measure a second cell voltage (or a second voltage) of the reference cell (e.g., reference cell 200 in FIG. 3) while charging the reference cell. The second cell voltage may be a voltage corresponding to the difference between the second positive electrode voltage and the second negative electrode voltage of the reference cell. The second positive electrode voltage may be a voltage corresponding to the potential difference between the reference electrode (e.g., reference electrode 203 in FIG. 3) and the second positive electrode (e.g., second positive electrode 201 in FIG. 3) of the reference cell. The second negative electrode voltage may be a voltage corresponding to the potential difference between the reference electrode and the second negative electrode (e.g., second negative electrode 202 in FIG. 3) of the reference cell.

[0048] In operation S23, the control unit (e.g., the control unit 122 in FIG. 4) calculates the voltage deviation between the first cell voltage of the battery cell and the second cell voltage of the reference cell, corrects the first cell voltage based on the calculated voltage deviation, and can estimate the SOH (state of health) of the battery module and battery pack including the battery cell based on the corrected first cell voltage.

[0049] As another example, the control unit can calculate a voltage deviation between a first cell voltage of a battery cell and a second cell voltage of a reference cell, and estimate the SOH (state of health) of a battery module and a battery pack including the battery cell based on the calculated voltage deviation. The control unit 122 can predict the degree of deterioration, replacement time, and lifespan of the battery cell based on the estimated SOH.

[0050] 8 is a graph showing the cell voltages of a battery cell according to the second embodiment of the present invention and a reference cell depending on the SOC. In FIG. 8, the horizontal axis represents the SOC (state of charge) (or remaining capacity) of the battery, and the vertical axis represents the cell voltages of the battery cell and the reference cell.

[0051] Referring to FIG. 8, a control unit (e.g., the control unit 122 in FIG. 4) may generate a first cell voltage profile 711 in which the first cell voltage gradually increases as the SOC of the battery cell increases (or the amount of lithium ions stored in the battery cell increases). The control unit may generate a second cell voltage profile 712 in which the second cell voltage gradually increases as the SOC of the reference cell increases (or the amount of lithium ions stored in the reference cell increases). The first cell voltage profile 711 and the second cell voltage profile 712 may be generated by a charging experiment on the battery cell and the reference cell. The control unit may calculate a voltage deviation between the first cell voltage and the second cell voltage based on the first cell voltage profile 711 and the second cell voltage profile 712. The control unit may accurately measure the state of health (SOH) of the battery cell based on the calculated voltage deviation.

[0052] The battery management system and battery management method described above are not limited to the embodiments illustrated in the drawings, and the structures illustrated in the drawings may be combined. The battery management system according to the present invention may combine the management method illustrated in FIG. 5 and the management method illustrated in FIG. 7. Furthermore, although the battery cells and reference cells according to the present invention have been described using a pouch-type structure as an example, they are not limited thereto and may also be applied to cylindrical or prismatic structures.

[0053] The battery pack described above can be applied to various devices, including, but not limited to, transportation means such as electric bicycles, electric cars, and hybrid vehicles, and can be applied to various devices that can use a battery pack.

[0054] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope equivalent to the technical concept of the present invention and the claims that will be described later by a person having ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0055] 101, 201: Positive electrode 102, 202: Negative electrode 110: Battery pack 120: Battery management system 121: Measuring part 122: Control unit 123: Storage area 130: Battery module 200: Reference cell 203:Reference electrode

Claims

1. a battery module including a plurality of battery cells; at least one reference cell having a larger number of electrodes than each of the plurality of battery cells; a battery management system that controls the plurality of battery cells and the reference cell; Including, The battery management system includes: measuring a first voltage of the plurality of battery cells; measuring a second voltage of the reference cell; The battery pack determines the state of the battery module based on a deviation between the first voltage and the second voltage.

2. each of the plurality of battery cells includes a first negative electrode and a first positive electrode; The battery pack of claim 1 , wherein the reference cell includes a second negative electrode, a second positive electrode, and a reference electrode.

3. the first voltage is a first negative electrode voltage of the battery cell; The battery pack according to claim 2 , wherein the second voltage is a second negative electrode voltage corresponding to a potential difference between a reference electrode of the reference cell and the second negative electrode.

4. The battery management system includes: measuring the first negative electrode voltage while charging the battery cell; The battery pack according to claim 3 , wherein the second negative electrode voltage is measured while the reference cell is being charged.

5. the first voltage is a first cell voltage corresponding to a potential difference between the first positive electrode and the first negative electrode; the second voltage is a second cell voltage corresponding to a difference between a second positive electrode voltage and a second negative electrode voltage; The second positive electrode voltage corresponds to a potential difference between the reference electrode and the second positive electrode, The battery pack according to claim 2 , wherein the second negative electrode voltage corresponds to a potential difference between the reference electrode and the second negative electrode.

6. The battery management system includes: measuring the first cell voltage while charging the battery cell; The battery pack according to claim 5 , wherein the second cell voltage is measured while the reference cell is being charged.

7. The battery management system includes: estimating a state of health (SOH) of the battery module based on a deviation between the first voltage and the second voltage; The battery pack according to claim 2 , wherein the state of the plurality of battery cells is determined based on the estimated SOH.

8. The battery management system includes: correcting the first voltage based on a deviation between the first voltage and the second voltage; estimating a state of health (SOH) of the battery module based on the corrected first voltage; The battery pack according to claim 2 , wherein the state of the plurality of battery cells is determined based on the estimated SOH.

9. a measurement unit that measures first voltages of a plurality of battery cells included in the battery module and measures a second voltage of at least one reference cell having a greater number of electrodes than each of the plurality of battery cells; a control unit that determines a state of the plurality of battery cells based on a deviation between the first voltage and the second voltage; a battery management system including:

10. The measurement unit measuring the first voltage while charging the battery cell including a first negative electrode and a first positive electrode; The battery management system of claim 9 , wherein the second voltage is measured while charging the reference cell, which includes a second negative electrode, a second positive electrode, and a reference electrode.

11. measuring first voltages of a plurality of battery cells included in the battery module; measuring a second voltage of at least one reference cell that has a greater number of electrodes than each of the plurality of battery cells; determining a state of the plurality of battery cells based on a deviation between the first voltage and the second voltage; A battery management method comprising:

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