Battery management system, battery management method, and battery pack including same

Abstract

The present invention relates to a management battery system and method capable of accurately measuring characteristics of a battery cell, and a battery pack including the same. A battery pack according to one embodiment of the present invention may comprise: a battery module comprising a plurality of battery cells; at least one reference cell including more electrodes than the battery cell; and a battery management system that controls the battery unit and the reference unit, in which the battery management system may measure a first voltage of the battery unit and a second voltage of the reference unit, and determine a state of the battery module based on a difference between the first voltage and the second voltage.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0125848, filed on September 30, 2022, which is hereby incorporated by reference in its entirety. Technical Field

[0004] The present invention relates to a system and method for managing a battery and a battery pack including the system, and more particularly, to a system and method for managing a battery capable of accurately measuring characteristics of a battery cell and a battery pack including the system. Background Art

[0005] Recently, as the demand for portable electronic products such as notebook computers, camcorders, and mobile phones has rapidly increased, and the development of electric vehicles, batteries for energy storage, robots, and satellites has been standardized, many studies have been conducted on secondary batteries used as driving power sources thereof.

[0006] 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 in parallel. The state and operation of the battery pack are managed and controlled by a battery management system.

[0007] The battery management system may measure the electrical characteristics of the battery cells and determine the state of the battery based on the measured characteristics. However, when the electrical characteristics of the battery cells cannot be accurately measured, the state of the battery may not be correctly checked. Summary of the invention

[0008] Technical issues

[0009] Embodiments according to the present invention provide a system and method for managing a battery capable of accurately measuring characteristics of a battery cell, and a battery pack including the system.

[0010] The technical problems of the present invention are not limited to the above technical problems, and those skilled in the art can clearly understand other technical problems not mentioned above from the following disclosure.

[0011] Technical Solution

[0012] A battery pack according to one embodiment of the present invention may include: a battery module, the battery module including battery cells, the battery cells being arranged as a plurality of battery cells; at least one reference cell, the at least one reference cell including more electrodes than the battery cells; a battery management system, the battery management system being configured to control the battery cells and the reference cells, wherein the battery management system is configured to: measure a first voltage of the battery cells; measure a second voltage of the reference cells; and determine a state of the battery module based on a deviation between the first voltage and the second voltage.

[0013] 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.

[0014] According to one embodiment, the first voltage may be a first cathode voltage of the battery cell, and the second voltage may be a second cathode voltage corresponding to a potential difference between a reference electrode and a second cathode of the reference cell.

[0015] According to one embodiment, the battery management system may measure a first negative electrode voltage when charging the battery cell, and measure a second negative electrode voltage when charging the reference cell.

[0016] According to one embodiment, the first voltage may be a first unit voltage corresponding to a potential difference between a first positive electrode and a first negative electrode, and the second voltage may be a second unit voltage corresponding to a difference between a second positive electrode voltage and a second negative electrode voltage, wherein the second positive electrode voltage corresponds to the potential difference between a reference electrode and a second positive electrode, and the second negative electrode voltage corresponds to the potential difference between the reference electrode and the second negative electrode.

[0017] According to one embodiment, the battery management system may measure a first cell voltage when charging the battery cell, and measure a second cell voltage when charging the reference cell.

[0018] According to one embodiment, the battery management system may estimate a state of health (SOH) of the battery module based on a deviation between a first voltage and a second voltage, and determine a state of each of a plurality of battery cells based on the estimated SOH.

[0019] According to one embodiment, the battery management system may correct the first voltage based on a deviation between the first voltage and the second voltage, estimate the state of health (SOH) of the battery module based on the corrected first voltage, and determine the state of each of the plurality of battery cells based on the estimated SOH.

[0020] A battery management system according to one embodiment of the present invention may include: a measuring unit that measures a first voltage of a battery cell and measures a second voltage of at least one reference cell, the battery cell being arranged as a plurality of battery cells and included in a battery module, the at least one reference cell including more electrodes than the battery cell; and a controller that determines a state of each of the plurality of battery cells based on a deviation between the first voltage and the second voltage.

[0021] According to one embodiment, the measuring part may measure a first voltage when charging a battery cell including a first negative electrode and a first positive electrode, and measure a second voltage when charging a reference cell including a second negative electrode, a second positive electrode, and a reference electrode.

[0022] According to one embodiment of the present invention, a battery management method may include the following steps: measuring a first voltage of a battery cell, which is arranged as a plurality of battery cells and is included in a battery module; measuring a second voltage of at least one reference cell, which includes more electrodes than the battery cell; and determining a state of each of the plurality of battery cells based on a deviation between the first voltage and the second voltage.

[0023] Beneficial Effects

[0024] According to the present invention, electrical characteristics (eg, negative electrode voltage and cell voltage) of a battery cell can be accurately measured through a reference electrode included in the reference cell.

[0025] According to the present invention, the health state of a battery cell can be accurately measured based on at least one of the negative electrode voltage or the cell voltage.

[0026] According to the present invention, since the health state of a battery cell can be accurately measured, cell balancing can be performed.

[0027] In addition, various effects found directly or indirectly through this document can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a block diagram illustrating a battery pack according to the present invention.

[0029] Figure 2 is an example included in Figure 1 A perspective view of a battery cell in a battery module is shown.

[0030] Figure 3 is an example included in Figure 1 A plan view of a reference cell in a battery pack is shown.

[0031] Figure 4 is an example Figure 1Detailed block diagram of the battery management system shown in .

[0032] Figure 5 is a flowchart illustrating a battery management method according to a first embodiment of the present invention.

[0033] Figure 6 is a graph illustrating a negative electrode voltage according to a change in a state of charge (SOC) of each of the battery cell according to the first embodiment of the present invention and a reference cell.

[0034] Figure 7 is a flowchart illustrating a battery management method according to a second embodiment of the present invention.

[0035] Figure 8 is a graph illustrating a cell voltage according to a change in SOC of each of the battery cell according to the second embodiment of the present invention and a reference cell. DETAILED DESCRIPTION

[0036] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention belongs can easily implement the present invention. However, the present invention can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein.

[0037] In order to clearly describe the present invention, detailed description of parts irrelevant to the description or related well-known technologies that may unnecessarily obscure the subject matter of the present invention will be excluded. Throughout the specification, the same reference numerals represent the same elements.

[0038] Furthermore, the terms or words used in the specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts consistent with the scope of the present invention based on the principle that the inventor can appropriately define the concepts of the terms in order to best describe and interpret his or her invention.

[0039] Figure 1 is a block diagram illustrating a battery pack according to the present invention. Figure 2 is an example included in Figure 1 A perspective view of a battery cell in a battery module is shown. Figure 3 is an example included in Figure 1 A plan view of a reference cell in a battery pack is shown.

[0040] Reference Figures 1 to 3 , the battery pack 110 may include a reference cell 200 , a battery module 130 , and a battery management system 120 .

[0041] The battery module 130 may be provided in plurality, and each of the plurality of battery modules 130 may be provided in the form of a stacked body in which a plurality of battery cells 100 are stacked. Figure 2 As shown, each of the plurality of battery cells 100 may have a dual-electrode structure including a first positive electrode 101 (or working electrode) and a first negative electrode 102 (or counter electrode).

[0042] The reference cell 200 may be provided as at least one. The reference cell 200 may include more electrodes than the battery cell 100. The reference cell 200 may have a three-electrode structure including a second positive electrode 201, a second negative electrode 202, and a reference electrode 203.

[0043] When measuring the relative value of the electrode potential, the reference electrode 203 can be used as a potential standard. Since the current flows between the second positive electrode 201 and the second negative electrode 202, and the current hardly flows through the reference electrode 203, the potential of the reference electrode 203 itself does not change. When measuring the second negative electrode voltage corresponding to the potential difference between the reference electrode 203 and the second negative electrode 202 of the reference cell 200, the second negative electrode voltage can be accurately measured because the potential of the reference electrode 203 does not change. When measuring the second positive electrode voltage corresponding to the potential difference between the reference electrode 203 and the second positive electrode 201 of the reference cell 200, the second positive electrode voltage can be accurately measured because the potential of the reference electrode 203 itself does not change.

[0044] The battery management system 120 may include a plurality of terminals as interfaces for receiving values ​​obtained by measuring various parameters, circuits connected to the terminals to perform processing on the received values, and the like.

[0045] The battery management system 120 may monitor the voltage, current, temperature, etc. of the reference cell 200 and each battery cell 100 included in the battery module 130 to manage and control the battery cells so as to prevent overcharge, overdischarge, etc. of the battery cells 100 .

[0046] Figure 4 is an example Figure 1 Detailed block diagram of the battery management system shown in .

[0047] Reference Figure 4 The battery management system 120 may include a measuring section 121 , a controller 122 , and a storage section 123 .

[0048] The measuring unit 121 can measure the battery cell (for example, Figure 2 , and measuring a first voltage of a reference cell (eg, Figure 3 A second voltage of the reference cell 200 in FIG.

[0049] The measuring unit 121 may measure a first negative electrode voltage (or first voltage) of the battery cell when charging the battery cell. The measuring unit 121 may measure a first negative electrode voltage corresponding to a difference between a potential of the first negative electrode of the battery cell and a reference potential (e.g., 0V). The measuring unit 121 may measure a second negative electrode voltage (or second voltage) corresponding to a potential difference between a reference electrode and a second negative electrode of the reference cell when charging the reference cell.

[0050] The measuring part 121 may measure a first cathode voltage in an open circuit state of the battery cell, and measure a second cathode voltage in an open circuit state of the reference cell.

[0051] The controller 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 the reference cell. The controller 122 may be communicatively connected to the measuring unit 121 in a wired manner and / or wireless manner. The controller 122 may receive the first negative electrode voltage and the second negative electrode voltage from the measuring unit 121, and calculate a voltage deviation between the received first negative electrode voltage and the second negative electrode voltage.

[0052] As an example, the controller 122 may 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 the first positive electrode potential changes in a state where a current flows between the first positive electrode and the first negative electrode of the battery cell, the first negative electrode potential may also change, so the first negative electrode voltage is difficult to measure accurately. In contrast, in a reference cell including a reference electrode, the second negative electrode voltage can be accurately measured compared to the battery cell. Therefore, the controller 122 may 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 measuring section. The controller 122 may estimate the state of health (SOH) of each of the battery module and the battery pack including the battery cell based on the corrected first negative electrode voltage. The controller 122 may estimate the SOH of each of the battery module and the battery pack based on the correlation data between the first negative electrode voltage and the SOH measured in advance. The correlation data between the corrected first negative electrode voltage and the SOH may be pre-stored in the storage section 123. The correlation data between the corrected first negative electrode voltage and the SOH may be a value obtained in advance by at least one pre-estimation. In the storage section 123 , the correlation data between the corrected first cathode voltage and the SOH may be re-estimated at fixed intervals and periodically updated.

[0053] As another example, the controller 122 may estimate the state of health (SOH) of each of the battery module and the battery pack including the battery cell based on the voltage deviation between the first negative electrode voltage and the second negative electrode voltage. The controller 122 may estimate the SOH of each of the battery module and the battery pack based on the correlation data between the voltage deviation between the negative electrode voltages measured in advance and the SOH. The correlation data between the voltage deviation between the negative electrode voltages of the battery cell and the reference cell and the SOH may be pre-stored in the storage unit 123. The correlation data between the deviation between the negative electrode voltages of the battery cell and the reference cell and the SOH may be a value pre-obtained by at least one pre-estimation. In the storage unit 123, the correlation data between the deviation between the negative electrode voltages of the battery cell and the reference cell and the SOH may be re-estimated at fixed intervals and periodically updated.

[0054] The controller 122 may determine the state of each of the battery modules and battery packs including the battery cells based on the estimated SOH. The controller 122 may predict the degree of degradation, replacement time, life, etc. of the battery cells based on the estimated SOH. In addition, the controller 122 may select a battery cell to be balanced based on the SOH of each of the plurality of battery cells. For example, the controller 122 may compare the respective SOHs of the plurality of battery cells and select a battery cell whose SOH exceeds a threshold value as an object to be balanced. The controller 122 may perform balancing on the battery cells selected as the object to be balanced. Therefore, the battery modules and battery packs including the battery cells may be managed safely.

[0055] Figure 5 is a flowchart illustrating a battery management method according to a first embodiment of the present invention.

[0056] In operation S11, a measuring unit (eg, Figure 4 The measuring unit 121 in the embodiment may measure the battery cell (eg, Figure 2 The first negative electrode (eg, Figure 2 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 (eg, 0 V).

[0057] When the battery cell is charged, the first negative electrode voltage of the battery cell may decrease due to electrochemical phenomena in the battery cell. When the battery cell is continuously charged in a state where the negative electrode potential of the battery cell is low (e.g., 0V or lower), the negative electrode may be plated with metal, thereby reducing the life of the battery cell. Therefore, the present invention can measure the first negative electrode voltage of the battery cell so that the negative electrode potential of the battery cell is greater than the reference potential during the charging of the battery cell.

[0058] In operation S12, the measuring section may measure the reference cell (eg, Figure 3 The second negative voltage may be related to the reference electrode of the reference cell (eg, Figure 3 The reference electrode 203 in the embodiment of the present invention) and the second negative electrode (e.g., Figure 3 Corresponding to the potential difference between the second negative electrode 202).

[0059] In operation S13, a controller (eg, Figure 4 The controller 122 in the battery module can calculate a voltage deviation between a first negative electrode voltage of a battery cell and a second negative electrode voltage of a reference cell, correct the first negative electrode voltage based on the calculated voltage deviation, and estimate the state of health (SOH) of each of the battery modules and battery packs including the battery cells based on the corrected first negative electrode voltage.

[0060] As another example, the controller may calculate a voltage deviation between a first negative electrode voltage of a battery cell and a second negative electrode voltage of a reference cell, and estimate a state of health (SOH) of each of a battery module and a battery pack including the battery cell based on the calculated voltage deviation.

[0061] The controller can predict the degree of degradation, replacement time, life, etc. of the battery cell based on the estimated SOH. In addition, the controller can control the charging of the battery pack so that the first negative electrode voltage of the battery cell that has been measured (or corrected) by the measuring section is maintained at a fixed level or higher (or greater than a reference potential). Therefore, the life characteristics of the battery pack can be improved.

[0062] Figure 6 is a graph illustrating a negative electrode voltage according to a change in a state of charge (SOC) of each of the battery cell according to the first embodiment of the present invention and a reference cell. Figure 6 In the graph, the horizontal axis may indicate the SOC (or remaining capacity) of the battery, and the vertical axis may indicate the negative electrode voltage of each of the battery cell and the reference cell. SOC of 0 may mean that the negative electrode voltage reaches a predetermined upper limit voltage and the battery cell is in a fully discharged state, and SOC gradually increases from 0 may mean that as the negative electrode voltage gradually reaches a predetermined lower limit voltage, the battery cell is close to a fully charged state.

[0063] Reference Figure 6 , controller (e.g., Figure 4The controller 122 in the figure can generate a first negative electrode voltage curve 501, wherein the first negative electrode voltage gradually decreases as the state of charge of the battery cell increases (or the amount of lithium ions stored in the battery cell increases). The controller can generate a second negative electrode voltage curve 502, wherein the second negative electrode voltage gradually decreases as the state of charge of the reference cell increases (or the amount of lithium ions stored in the reference cell increases). The first negative electrode voltage curve 501 and the second negative electrode voltage curve 501 can be generated by performing charging experiments on the battery cell and the reference cell. The controller can calculate the voltage deviation between the first negative electrode voltage and the second negative electrode voltage based on the first negative electrode voltage curve 501 and the second negative electrode voltage curve 502. The controller can estimate the state of health (SOH) of the battery cell based on the calculated voltage deviation.

[0064] Figure 7 is a flowchart illustrating a battery management method according to a second embodiment of the present invention.

[0065] In operation S21, a measuring unit (eg, Figure 4 The measuring unit 121 in the embodiment may measure the battery cell (eg, Figure 2 The first cell voltage may be a first positive electrode of the battery cell (eg, Figure 2 The first positive electrode 101) and the first negative electrode (for example, Figure 2 A voltage corresponding to the potential difference between the first negative electrode 102 in the embodiment.

[0066] In operation S22, the measuring section may measure the reference cell (eg, Figure 3 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 difference between the reference electrode (e.g., Figure 3 The reference electrode 203 in the embodiment of the present invention and the second positive electrode (e.g., Figure 3 The second cathode voltage may be a voltage corresponding to the potential difference between the reference electrode and the second cathode (eg, Figure 3 A voltage corresponding to the potential difference between the second negative electrode 202 in the embodiment.

[0067] In operation S23, the controller (eg, Figure 4The controller 122 in the battery cell may calculate a voltage deviation between a first cell voltage of a battery cell and a second cell voltage of a reference cell, correct the first cell voltage based on the calculated voltage deviation, and estimate a state of health (SOH) of each of a battery module and a battery pack including the battery cell based on the corrected first cell voltage.

[0068] As another example, the controller may calculate a voltage deviation between a first cell voltage of a battery cell and a second cell voltage of a reference cell, and estimate a state of health (SOH) of each of a battery module and a battery pack including the battery cell based on the calculated voltage deviation.

[0069] The controller 122 may predict the degree of degradation, replacement time, life span, etc. of the battery cell based on the estimated SOH.

[0070] Figure 8 is a graph illustrating a cell voltage according to a change in a state of charge (SOC) of each of a battery cell and a reference cell according to a second embodiment of the present invention. Figure 8 , the horizontal axis may indicate the SOC (or remaining capacity) of the battery, and the vertical axis may indicate the cell voltage of each of the battery cell and the reference cell.

[0071] Reference Figure 8 , controller (e.g., Figure 4 The controller 122 in the battery may generate a first cell voltage curve 711, wherein the first cell voltage gradually increases as the state of charge of the battery increases (or the amount of lithium ions stored in the battery increases). The controller may generate a second cell voltage curve 712, wherein the second cell voltage gradually increases as the state of charge of the reference cell increases (or the amount of lithium ions stored in the reference cell increases). The first cell voltage curve 711 and the second cell voltage curve 712 may be generated by performing a charging experiment on the battery cell and the reference cell. The controller may calculate a voltage deviation between the first cell voltage and the second cell voltage based on the first cell voltage curve 711 and the second cell voltage curve 712. The controller may accurately measure the state of health (SOH) of the battery cell based on the calculated voltage deviation.

[0072] The above-mentioned battery management system and battery management method are not limited to the embodiments described with reference to the accompanying drawings respectively, and the various structures described in the accompanying drawings can be applied in combination with each other. Figure 5 Used in conjunction with the management methods described, or with reference Figure 7 The management method described is used in combination. In addition, the battery cell and the reference cell according to the present invention are described using the example of a pouch-type structure, but are not limited thereto. The battery cell and the reference cell can be applied to a cylindrical structure or a prismatic structure.

[0073] The above-mentioned battery pack can be applied to various devices. The battery pack can be applied to transportation devices such as electric bicycles, electric vehicles or hybrid vehicles. However, the battery pack is not limited thereto and can be applied to various devices that can use the battery pack.

[0074] Although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto and can be implemented in various ways by a person skilled in the art to which the present invention pertains within the technical idea of ​​the present invention and equivalents of the appended claims.

[0075] [Explanation of Reference Numerals]

[0076] 101, 201: positive electrode

[0077] 102, 202: Negative electrode

[0078] 110: Battery Pack

[0079] 120: Battery Management System

[0080] 121: Measurement Department

[0081] 122: Controller

[0082] 123: Storage

[0083] 130: Battery module

[0084] 200: Reference unit

[0085] 203: Reference electrode

Claims

1. A battery pack, comprising: A battery module, the battery module comprising a battery cell, the battery cell being arranged as a plurality of battery cells; at least one reference cell, the at least one reference cell comprising more electrodes than the battery cell; a battery management system configured to control the battery cell and the reference cell, Wherein, the battery management system is configured as follows: measuring a first voltage of the battery cell; measuring a second voltage of the reference cell; and A state of the battery module is determined based on a deviation between the first voltage and the second voltage.

2. The battery pack according to claim 1, wherein: Each of the plurality of battery cells includes a first negative electrode and a first positive electrode, and The reference unit includes a second cathode, a second anode and a reference electrode.

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

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

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

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

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

8. The battery pack according to claim 2, wherein: The battery management system is configured to: 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; as well as A state of each of the plurality of battery cells is determined based on the estimated SOH.

9. A battery management system, comprising: a measuring section configured to measure a first voltage of a battery cell, the battery cell being provided as a plurality of battery cells and included in a battery module, and to measure a second voltage of at least one reference cell, the at least one reference cell including more electrodes than the battery cell; as well as A controller is configured to determine a state of each of the plurality of battery cells based on a deviation between the first voltage and the second voltage.

10. The battery management system according to claim 9, wherein: The measuring unit is configured as follows: measuring the first voltage while charging the battery cell including a first negative electrode and a first positive electrode; and The second voltage is measured while charging the reference cell including a second negative electrode, a second positive electrode, and a reference electrode.

11. A battery management method, the battery management method comprising the following steps: measuring a first voltage of a battery cell, the battery cell being arranged as a plurality of battery cells and included in a battery module; measuring a second voltage of at least one reference cell, the at least one reference cell comprising more electrodes than the battery cell; as well as A state of each of the plurality of battery cells is determined based on a deviation between the first voltage and the second voltage.

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