Battery control apparatus and method

Abstract

A battery control device includes: a connector that turns on or off a connection state between a plurality of batteries and an output terminal to which a discharge current is output for each battery; and a controller that controls the connector such that the plurality of batteries are connected in parallel to each other to the output terminal and are discharged during a first discharge period, the first discharge period is a time from a start time of discharge of the plurality of batteries for which the SOC of each of the plurality of batteries is a predetermined reference value or more to a time when the SOC of at least one of the plurality of batteries reaches the reference value.

Description

Technical Field

[0001] This application is based on and claims the benefit of priority from Korean Patent Application No. 10-2023-0140958 filed on October 20, 2023, in the Korean Intellectual Property Office, and Korean Patent Application No. 10-2024-0052075 filed on April 18, 2024, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference in their entirety.

[0002] The present disclosure relates to a battery control device and method, and more particularly to a battery control device and method for controlling a plurality of independently rechargeable batteries. Background Art

[0003] Generally, a secondary battery refers to a battery that can be repeatedly charged and discharged. A battery cell is the most basic secondary battery and can provide an output voltage of approximately 2.5 V to 4.2 V.

[0004] Typical examples of secondary batteries developed to date include lithium-sulfur batteries, in addition to lithium-ion batteries, lithium-polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. Lithium-sulfur batteries, in particular, have the advantages of storing a large amount of energy per unit weight, being manufactured at low cost, and being highly safe, compared to other types of batteries.

[0005] In recent years, secondary batteries have been applied to devices requiring high output voltage and large capacity, such as electric vehicles, aircraft, ships, and energy storage systems (ESS), which has led to the widespread use of battery modules or battery packs in which multiple battery cells are connected to each other in series and / or parallel, and battery packs in which multiple battery cells or multiple battery modules are connected to each other in series and / or parallel.

[0006] However, in conventional technology, in order to ensure a large amount of electrical capacity, all of the multiple independent rechargeable batteries are charged, and then the charged batteries are continuously discharged one by one until each battery is fully discharged. Therefore, conventional technology has a problem of reducing the discharge performance of batteries such as lithium-sulfur batteries that rapidly self-discharge when left idle in a high SOC state, and increasing the error in the estimated SOC value associated with the battery. Summary of the Invention

[0007] Technical issues

[0008] Embodiments of the present disclosure provide a battery control apparatus and method that prevents degradation in performance of a battery that rapidly self-discharges when left idle in a high SOC state, and reduces errors in an estimated SOC value associated with the battery.

[0009] Another embodiment of the present disclosure provides a battery control apparatus and method that improves discharge capacity and energy density per unit weight of a battery system including a plurality of batteries.

[0010] Yet another embodiment of the present disclosure provides a battery system and a vehicle, which include the battery control device according to the present disclosure.

[0011] Technical Solution

[0012] According to one aspect of the present disclosure, a battery control device for controlling discharge of a plurality of batteries includes: a connector configured to connect or disconnect, for each of the plurality of batteries, a connection between the plurality of batteries and an output terminal to which a discharge current is output; and a controller configured to control the connector so that the plurality of batteries are connected to the output terminal in parallel with each other and discharged during a first discharge period, and are alternately connected to the output terminal and discharged during a second discharge period, the first discharge period being from a start time of discharge of the plurality of batteries having a state of charge (SOC) of each battery equal to or greater than a predetermined reference value until the SOC of at least one of the plurality of batteries reaches the reference value, and the second discharge period being from a time when the SOC of each of the plurality of batteries becomes lower than the reference value until discharge of the plurality of batteries is terminated.

[0013] In an embodiment, the connector may include a plurality of switches corresponding to the plurality of batteries, respectively.

[0014] In an embodiment, the controller may be configured to discharge each of the plurality of batteries at a first current rate during a first discharge period, and to discharge the batteries connected to the output terminal among the plurality of batteries at a second current rate higher than the first current rate during a second discharge period.

[0015] In an embodiment, the controller may be configured to switch a battery disconnected from the output terminal among the plurality of batteries into an idle state during the second discharge period.

[0016] In an embodiment, the controller may be configured such that, during the second discharge period, when the connection time of the first battery connected to the output terminal exceeds a predetermined reference time, a second battery selected from the remaining batteries excluding the first battery among the plurality of batteries is connected to the output terminal, and the connection of the first battery is cut off.

[0017] In an embodiment, the second battery may be a battery having the highest voltage among the remaining batteries.

[0018] In an embodiment, the second battery may be a battery that has been disconnected from the output terminal for the longest period of time among the remaining batteries.

[0019] In an embodiment, the controller may include: a data acquisition module configured to acquire data about electrical characteristic values ​​of a plurality of batteries using at least one electrical sensor; an SOC information generation module configured to generate SOC information indicating an SOC value of each of the plurality of batteries using the data; and a connection control module configured to control the connector according to the SOC values ​​of the plurality of batteries indicated in the SOC information.

[0020] In an embodiment, the plurality of batteries may include at least one lithium-sulfur battery.

[0021] According to another aspect of the present disclosure, a battery system includes the above-mentioned battery control device.

[0022] According to yet another aspect of the present disclosure, a vehicle includes the battery control device described above.

[0023] According to yet another aspect of the present disclosure, a battery control method for controlling discharge of a plurality of batteries includes: a first discharge step in which the plurality of batteries are connected to an output terminal in parallel with each other and are discharged during a first discharge period, the first discharge period being a time from when discharge of the plurality of batteries is started when a state of charge (SOC) of each battery is equal to or greater than a predetermined reference value until the SOC of at least one of the plurality of batteries reaches a reference value; and a second discharge step in which the plurality of batteries are alternately connected to the output terminal and are discharged during a second discharge period, the second discharge period being a time from when the SOC of each of the plurality of batteries becomes lower than a reference value until discharge of the plurality of batteries is terminated.

[0024] In an embodiment, in a first discharging step, each of the plurality of batteries may be discharged at a first current rate, and in a second discharging step, batteries connected to the output terminal among the plurality of batteries may be discharged at a second current rate higher than the first current rate during a second discharging period.

[0025] In an embodiment, in the second discharging step, a battery disconnected from the output terminal among the plurality of batteries may be switched to enter an idle state.

[0026] In an embodiment, in the second discharging step, when a connection time of the first battery connected to the output terminal exceeds a predetermined reference time, a second battery selected from the remaining batteries excluding the first battery among the plurality of batteries may be connected to the output terminal, and the connection of the first battery may be cut off.

[0027] Effects of the Invention

[0028] In the present disclosure, during a first discharge period in which the SOC of each of a plurality of batteries is equal to or greater than a predetermined reference value, the plurality of batteries are connected in parallel to one another at an output terminal and are discharged together, so that performance degradation of batteries that rapidly self-discharge when left idle in a high SOC state can be prevented, and errors in estimated SOC values ​​associated with the batteries are reduced.

[0029] Furthermore, in the present disclosure, during the second discharge period in which the SOC of each of the plurality of batteries falls below a reference value, the plurality of batteries are alternately connected to the output terminal and discharged, so that each battery is not continuously discharged after a predetermined reference time has elapsed. Thus, it is possible to improve the discharge capacity per unit weight, energy density, and coulombic efficiency of a battery system including the plurality of batteries, and prevent accidents caused by overheating.

[0030] Furthermore, the present disclosure controls the increase in voltage differences among multiple batteries during discharge, preventing surge current from occurring when batteries with large voltage differences are connected in parallel. This prevents damage to the batteries, improves safety, and allows multiple batteries to be charged simultaneously, reducing charging time.

[0031] Furthermore, in the present disclosure, the lithium-sulfur battery can be applied to a battery system requiring high capacity, so that the energy density and safety of the battery system can be improved and the manufacturing cost can be reduced.

[0032] According to the following description, a person skilled in the art to which the present disclosure pertains can obviously understand that various embodiments of the present disclosure can solve other technical problems not described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a block diagram illustrating a battery control device according to an embodiment of the present disclosure.

[0034] Figure 2 1 is a diagram showing a first connection state between a plurality of batteries and output terminals.

[0035] Figure 3 FIG. 1 is a diagram showing a second connection state between a plurality of batteries and the output terminal.

[0036] Figure 4 1 is a diagram showing a third connection state between a plurality of batteries and the output terminal.

[0037] Figure 5 is a timing diagram illustrating the discharge sequence of multiple batteries.

[0038] Figure 6 is a flowchart illustrating a battery control method according to an embodiment of the present disclosure.

[0039] Figure 7 is a flowchart illustrating a battery connection process of a battery control method according to an embodiment of the present disclosure.

[0040] Figure 8 is a graph showing changes in discharge capacity per unit weight according to an increase in the number of charge / discharge cycles of lithium-sulfur batteries discharged at different current rates.

[0041] Figure 9 is a graph showing changes in energy density according to an increase in the number of charge / discharge cycles of lithium-sulfur batteries discharged at different current rates.

[0042] Figure 10 is a graph showing changes in coulombic efficiency according to an increase in the number of charge / discharge cycles of lithium-sulfur batteries discharged at different current rates.

[0043] Figure 11 is a graph showing changes in discharge capacity per unit weight according to an increase in the number of charge / discharge cycles of lithium-sulfur batteries discharged by different methods.

[0044] Figure 12 is a graph showing changes in energy density according to an increase in the number of charge / discharge cycles of lithium-sulfur batteries discharged by different methods.

[0045] Figure 13 is a graph showing changes in coulombic efficiency according to an increase in the number of charge / discharge cycles of lithium-sulfur batteries discharged by different methods.

[0046] Figure 14 is a view illustrating a battery system according to an embodiment of the present disclosure.

[0047] Figure 15 is a view illustrating a vehicle according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0048] In the following, embodiments of the present disclosure are described in detail with reference to the accompanying drawings to clearly describe the technology of the present disclosure. In describing the present disclosure, if the description of the relevant known technology will obscure the main points of the present disclosure, they may be omitted. In addition, the terms used herein are defined in consideration of their functions in the present disclosure and may vary according to the intentions or conventions of designers, manufacturers and others. Therefore, the terms to be described below in this document should be defined based on the entire specification of this document.

[0049] Figure 1 is a block diagram illustrating a battery control device 100 according to an embodiment of the present disclosure.

[0050] like Figure 1 As shown, the battery control device 100 according to an embodiment of the present disclosure includes a connection unit 110 and a control unit 120, and is configured to control the discharge of at least a plurality of batteries.

[0051] Each of the multiple batteries controlled by the battery control device 100 according to the present disclosure can be implemented as a battery cell as the most basic secondary battery, as a battery module including multiple battery cells connected in series and / or parallel to each other, or as a battery pack including multiple battery cells or multiple battery modules connected in series and / or parallel to each other.

[0052] Furthermore, the plurality of batteries may include at least one lithium-sulfur battery. A lithium-sulfur battery is a battery in which a first active material containing sulfur is applied to the positive electrode and a second active material containing lithium is applied to the negative electrode. Compared to other types of batteries, lithium-sulfur batteries have the advantages of storing a large amount of energy per unit weight, being manufactured at low cost, and having high safety.

[0053] The connection unit 110 is configured to connect or disconnect, for each battery, a connection between the plurality of batteries and an output terminal to which a discharge current is output.

[0054] In an embodiment, the connection unit 110 may include a plurality of switches corresponding to the plurality of batteries, respectively. In this case, each switch may be configured to electrically connect or disconnect a corresponding battery among the plurality of batteries and the output terminal.

[0055] Each of the plurality of switches included in the connection unit 110 may be implemented in various forms or structures according to the output of the corresponding battery. For example, each of the plurality of switches may be implemented as a relay or a switching semiconductor element.

[0056] The control unit 120 is configured to control the connection unit 110. That is, the control unit 120 may control the connection unit 110 so that at least one battery among the plurality of batteries is connected to the output terminal and discharged.

[0057] In particular, the control unit 120 can control the connection unit 110 so that during a first discharge period from the start time of discharging of the plurality of batteries at which the state of charge of each battery is equal to or greater than a predetermined reference value until the time when the SOC of at least one of the plurality of batteries reaches a reference value, the plurality of batteries are connected to the output terminal in parallel with each other and are discharged together.

[0058] In addition, the control unit 120 may control the connection unit 110 so that the plurality of batteries are alternately connected to the output terminal and discharged during a second discharge period from when the SOC of each of the plurality of batteries becomes lower than a reference value until when discharge of the plurality of batteries is terminated.

[0059] In this case, the reference value may be determined based on the self-discharge rate of the battery controlled by the battery control device 100 of the present disclosure. For example, when the battery to be controlled is a battery such as a lithium-sulfur battery that rapidly self-discharges when the SOC is 75% or greater and exhibits a sharply reduced self-discharge rate when the SOC is less than 75%, the reference value may be determined to be 75%.

[0060] Furthermore, the control unit 120 may be configured such that, among the plurality of batteries, a battery disconnected from the output terminal during the second discharge period is switched to enter the idle state.

[0061] Furthermore, the control unit 120 may be configured so that, when the connection time of the first battery connected to the output terminal during the second discharge period exceeds a predetermined reference time, a second battery selected from the remaining batteries other than the first battery among the plurality of batteries is connected to the output terminal, and the connection of the first battery is disconnected. The reference time may be determined as the time when the voltage difference among the batteries due to discharge of any one of the plurality of batteries does not exceed a predetermined threshold value (e.g., 10V).

[0062] In this case, the second battery may be the battery with the highest voltage among the remaining batteries. That is, the control unit 120 may select the second battery with the highest voltage among the remaining batteries as the battery to be discharged after the first battery.

[0063] In another embodiment, the second battery may be a battery that has not been connected to the output terminal for the longest period of time among the remaining batteries. That is, the control unit 120 may select the second battery that has not been connected to the output terminal for the longest period of time among the remaining batteries as the battery to be discharged after the first battery.

[0064] In this manner, the present disclosure can control the increase in voltage differences among multiple batteries during discharge, thereby preventing inrush current from occurring when batteries with large voltage differences are connected in parallel. As a result, damage to the batteries can be prevented, safety can be improved, and multiple batteries can be charged simultaneously, reducing charging time.

[0065] At the same time, the control unit 120 can control the connection unit 110 as described above to discharge each of the multiple batteries at a first current rate during the first discharge period, and discharge the battery connected to the output terminal among the multiple batteries at a second current rate higher than the first current rate during the second discharge period.

[0066] In another embodiment, the control unit 120 may regulate the current rate of the plurality of batteries by adjusting a duty cycle of a discharge current discharged from each of the plurality of batteries or by controlling an output of an electric device using the discharge current.

[0067] As described above, in the present disclosure, during the first discharge period in which the SOC of each of the plurality of batteries is equal to or greater than a predetermined reference value, the plurality of batteries are connected in parallel to the output terminal and discharged together. Therefore, it is possible to prevent degradation in battery performance due to self-discharge of batteries that rapidly self-discharge when left idle in a high SOC state, and it is possible to reduce errors in the estimated SOC values ​​associated with the batteries.

[0068] Furthermore, in the present disclosure, during the second discharge period in which the SOC of each of the plurality of batteries falls below a reference value, the plurality of batteries are alternately connected to the output terminal and discharged, thereby preventing each battery from continuing to be discharged after a predetermined reference time has elapsed. Consequently, the discharge capacity per unit weight, energy density, and coulombic efficiency of a battery system including the plurality of batteries can be improved, and accidents caused by overheating can be prevented.

[0069] Therefore, the present disclosure can solve the problem of lithium-sulfur batteries that exhibit a high self-discharge rate at a high SOC state and have a relatively low discharge current compared to other types of batteries, and can expand the application fields of lithium-sulfur batteries.

[0070] In an embodiment, the control unit 120 may include a data acquisition module 122 , an SOC information generation module 124 , and a connection control module 124 .

[0071] The data acquisition module 122 may be configured to acquire data on electrical characteristic values ​​of a plurality of batteries by using at least one electrical sensor. In this case, the electrical characteristic values ​​may include a voltage value and a current value of each of the plurality of batteries.

[0072] The SOC information generation module 124 may be configured to generate SOC information indicating an SOC value of each of the plurality of batteries using the data acquired by the data acquisition module 122. For example, the SOC information generation module 124 may generate the SOC information using an SOC-OCV curve that indicates a correlation between a state of charge (SOC) and an open circuit voltage (OCV) of each of the batteries or using a current integration method.

[0073] The connection control module 124 may be configured to control the connection unit 110 based on the SOC values ​​of the plurality of batteries indicated in the SOC information.

[0074] The connection control module 124 may control the connection unit 110 so that, during a first discharge period in which the SOC of all of the plurality of batteries is equal to or greater than a predetermined reference value in the entire discharge period of the plurality of batteries, the plurality of batteries are connected to the output terminal in parallel with each other and discharged together. For example, during a period in which the SOC of each of the plurality of batteries decreases from 100% to 75%, the connection control module 124 may connect the plurality of batteries to the output terminal in parallel with each other.

[0075] Then, the connection control module 124 may control the connection unit 110 so that the plurality of batteries are alternately connected to the output terminal and discharged during the second discharge period in which the SOC of each of the plurality of batteries becomes lower than a reference value.

[0076] For example, when the discharge of the plurality of batteries progresses so that the SOCs of all of the plurality of batteries become lower than 75%, the connection control module 124 may disconnect the parallel connection of the plurality of batteries and alternately connect the plurality of batteries to the output terminals.

[0077] Meanwhile, when the plurality of batteries are discharged simultaneously during the first discharge period, but the SOC of only a portion of the plurality of batteries becomes lower than the reference value while the SOC of the remaining batteries is still equal to or greater than the reference value, the control unit 120 may maintain the parallel connection of the plurality of batteries to the output terminal until the SOC of all of the plurality of batteries becomes lower than the reference value.

[0078] In another embodiment, the control unit 120 may be configured such that, when a plurality of batteries are discharged simultaneously during a first discharge period, but the SOC of only a portion of the plurality of batteries becomes lower than a reference value while the SOC of the remaining batteries is still equal to or greater than the reference value, the connection between the portion of the plurality of batteries and the output terminal is cut off to switch the portion of the plurality of batteries into an idle state, and the connection between the remaining batteries and the output terminal is maintained.

[0079] The control unit 120 described above may include one or two or more general-purpose processors or application-specific integrated circuits (ASICs) to execute the battery control logic, and may also include hardware components such as registers and memory according to the embodiment. The control unit 120 may be implemented as a combination of hardware components such as a processor and software components such as a computing program. That is, the battery control logic of the connection unit 110 may be implemented as a computing program, which may be stored in the control unit 120's own memory or in the storage unit 130 to be described later, and executed by the hardware components of the control unit 120.

[0080] In an embodiment, the battery control device 100 may further include a storage unit 130. The storage unit 130 may be configured to store and manage data required for the operation of the battery control device 100. To this end, the storage unit 130 may include one or two or more of ROM, RAM, EEPROM, registers, flash memory, CD-ROM, magnetic tape, hard disk, floppy disk, and optical data recorder.

[0081] In an embodiment, the battery control device 100 can be configured to operate in collaboration with, for example, a measuring device 12 including at least one electrical sensor for measuring the voltage, charging current and / or discharging current of each of a plurality of batteries, a charging device 14 for charging the plurality of batteries, and a communication device 16 for communicating with other devices.

[0082] In another embodiment, the battery control device 100 according to the present disclosure may include at least one of the aforementioned measuring device 12 , charging device 14 , and communication device 16 .

[0083] Figure 2 is a diagram showing a first connection state between a plurality of batteries and output terminals.

[0084] like Figure 2 As shown, the connection unit 110 of the battery control device according to the present disclosure is configured to connect or disconnect, for each battery, the connection between the battery pack BG including the plurality of batteries B1 to B3 and the output terminal BT to which the discharge current is output. To this end, the connection unit 110 may include a plurality of switches S1 to S3 corresponding to the plurality of batteries B1 to B3, respectively.

[0085] As described above, each of the plurality of switches S1 to S3 can be implemented in various forms or structures according to the output of the corresponding battery. For example, when each of the plurality of batteries B1 to B3 is configured with a battery module or battery pack including a plurality of battery cells connected in series and / or in parallel, each of the plurality of switches S1 to S3 can be implemented as a relay.

[0086] During a first discharging period from the start time of discharging of the plurality of batteries B1 to B3 until the SOC of at least one of the plurality of batteries reaches a reference value (e.g., 75%), the control unit 120 may turn on all of the plurality of switches S1 to S3 so that the plurality of batteries B1 to B3 are connected to the output terminal BT in parallel with each other and are discharged together.

[0087] In this case, each of the plurality of batteries B1 to B3 may be discharged at a first current rate. For example, each battery may be discharged at a current rate of 0.1 [C] so that a total discharge current of 0.3 [C] may be output to the output terminal BT.

[0088] Figure 3 is a diagram showing a second connection state between a plurality of batteries and the output terminals.

[0089] like Figure 3 As shown, during the second discharge period from the time when the SOC of all the multiple batteries B1 to B3 becomes lower than the reference value until the time when the discharge of the multiple batteries is terminated, the control unit 120 can control the connection unit 110 so that the multiple batteries are alternately connected to the output terminal and discharged.

[0090] For example, the control unit 120 may maintain the connection state of the first switch S1 among the plurality of switches S1 to S3 and cut off the remaining switches S2 and S3 to connect only the first battery B1 among the plurality of batteries B1 to B3 to the output terminal BT.

[0091] In this case, the first battery B1 connected to the output terminal BT is discharged at a second current rate higher than the first current rate, and the remaining batteries B2 and B3 can be switched to enter an idle state. For example, the first battery B1 can be discharged at a current rate of 0.3 [C], so that a total discharge current of 0.3 [C] can be output to the output terminal BT.

[0092] Figure 4 is a diagram showing a third connection state between the plurality of batteries and the output terminals.

[0093] like Figure 4 As shown, when the connection time of the first battery B1 connected to the output terminal BT exceeds a predetermined reference time, the control unit 120 may connect a second battery B2 selected from the remaining batteries B2 and B3 except the first battery B1 to the output terminal BT and cut off the connection of the first battery B1.

[0094] In this case, the second battery B2 may be a battery having the highest voltage among the remaining batteries B2 and B3 or a battery that has not been connected to the output terminal BT for the longest period of time among the remaining batteries B2 and B3.

[0095] The control unit 120 may maintain the off state of the third switch S3 among the plurality of switches S1 to S3 , turn on the second switch S2 , and turn off the first switch S1 , so that only the second battery B2 among the plurality of batteries B1 to B3 may be connected to the output terminal BT.

[0096] In this case, the second battery B2 connected to the output terminal BT can be discharged at a second current rate higher than the first current rate, the first battery B1 can be switched to enter the idle state, and the third battery B3 can be maintained in the idle state. For example, the second battery B2 can be discharged at a current rate of 0.3 [C], so that a total discharge current of 0.3 [C] is output to the output terminal BT.

[0097] Figure 5 is a timing diagram illustrating the discharge sequence of multiple batteries.

[0098] like Figure 5 As shown, the plurality of batteries B1 to B3 controlled according to the present disclosure are discharged together during a first discharge period t1-to of the entire discharge period.

[0099] The plurality of batteries B1 to B3 are alternately discharged after the first discharge period t1-to. In this case, each battery can repeatedly undergo a discharge and idle state until the end of the discharge. For example, each battery can repeatedly undergo a discharge of time T and an idle state of time 2T.

[0100] Figure 6 is a flowchart illustrating a battery control method according to an embodiment of the present disclosure.

[0101] like Figure 6 As shown, the battery control method according to the present disclosure is a method of controlling at least the discharge of a plurality of batteries, and includes a first discharge step and a second discharge step.

[0102] In the first discharging step, a plurality of batteries each having an SOC equal to or greater than a predetermined reference value are connected in parallel to an output terminal and discharged together during a first discharging period from a start time of discharging until a time when the SOC of at least one of the plurality of batteries reaches a reference value (S610 to S650).

[0103] In a first discharging step, each battery of the plurality of batteries may be discharged at a first current rate.

[0104] Furthermore, in the second discharging step, the plurality of batteries are alternately connected to the output terminal and discharged during a second discharging period from when the SOC of each of the plurality of batteries becomes lower than a reference value until discharging of the plurality of batteries is terminated ( S610 to S650 ).

[0105] In the second discharging step, among the plurality of batteries, the battery connected to the output terminal may be discharged at a second current rate higher than the first current rate.

[0106] Further, in the second discharging step, among the plurality of batteries, batteries disconnected from the output terminal may be switched to enter an idle state.

[0107] Furthermore, in the second discharging step, when the connection time of the first battery connected to the output terminal exceeds a predetermined reference time, a second battery selected from the remaining batteries excluding the first battery among the plurality of batteries is connected to the output terminal, and the connection of the first battery may be cut off.

[0108] In an embodiment, the plurality of batteries may include at least one lithium-sulfur battery.

[0109] More specifically, the data acquisition module 122 of the control unit 120 acquires data on electrical characteristic values ​​of the plurality of batteries using at least one electrical sensor (S610). In this case, the electrical characteristic values ​​may include a voltage value and a current value of each of the plurality of batteries.

[0110] Then, the SOC information generation module 124 of the control unit 120 generates SOC information indicating the SOC value of each of the plurality of batteries by using the data acquired by the data acquisition module 122 (S620). For example, the SOC information generation module 124 may generate the SOC information using an SOC-OCV curve that indicates the correlation between the SOC and the OCV of each of the batteries or using a current integration method.

[0111] As a result, the connection control module 124 of the control unit 120 may control the connection unit 110 according to the SOC values ​​of the plurality of batteries indicated in the SOC information.

[0112] That is, the connection control module 124 compares the SOC values ​​of the plurality of batteries with the reference value Rc ( S630 ).

[0113] As a result of comparison between the SOC values ​​of the plurality of batteries and the reference value Rc, when the SOCs of all of the plurality of batteries are equal to or greater than the reference value Rc, the connection control module 124 discharges the plurality of batteries together by connecting the batteries in parallel to each other at the output terminal ( S640 and S650 ).

[0114] For example, when the reference value Rc is 75% and the SOC of all the batteries of the plurality of batteries is within the range of 100% to 75%, the connection control module 124 may connect the plurality of batteries in parallel to the output terminal. In this case, each of the plurality of batteries may be discharged at a first current rate.

[0115] When the SOCs of all of the batteries become lower than the reference value Rc as the discharge of the batteries progresses, the connection control module 124 alternately connects the batteries to the output terminals and discharges the batteries one by one.

[0116] For example, when the reference value Rc is 75% and the SOC of each of the plurality of batteries is lower than 75%, the connection control module 124 may disconnect the parallel connection among the plurality of batteries and alternately connect the plurality of batteries to the output terminal. In this case, among the plurality of batteries, the battery connected to the output terminal may be discharged at a second current rate higher than the first current rate.

[0117] The above steps S610 to S660 may be repeated until the discharging of the plurality of batteries is completed ( S670 ).

[0118] Figure 7 is a flowchart illustrating a battery connection process of a battery control method according to an embodiment of the present disclosure.

[0119] like Figure 7 As shown, when the SOCs of all the batteries become lower than the reference value Rc as the discharge of the plurality of batteries proceeds, the connection control module 124 of the connection unit 110 may alternately connect the plurality of batteries to the output terminal and discharge the batteries one by one.

[0120] Specifically, when the SOCs of all the batteries among the plurality of batteries become lower than the reference value Rc as the discharge of the plurality of batteries progresses, the connection control module 124 cuts off the connections of the remaining batteries except for the first battery selected from the plurality of batteries to connect only the first battery among the plurality of batteries to the output terminal (S710).

[0121] In this case, the control unit 120 may maintain the connection state of the first battery until a predetermined reference time has passed (S720 and S730). In addition, the remaining batteries may be maintained in an idle state during the reference time.

[0122] Then, when the connection time of the first battery connected to the output terminal exceeds a predetermined reference time, the connection control module 124 may connect a second battery selected from the remaining batteries except the first battery to the output terminal and cut off the connection of the first battery to connect only the second battery among the plurality of batteries to the output terminal (S740).

[0123] In this case, the second battery may be a battery having the highest voltage among the remaining batteries, or a battery that has not been connected to the output terminal for the longest period of time among the remaining batteries.

[0124] The above steps S720 to S740 may be repeated until the discharging of the plurality of batteries is completed ( S750 ).

[0125] Figure 8 is a graph showing changes in discharge capacity per unit weight according to an increase in the number of charge and discharge cycles of lithium-sulfur batteries discharged at different current rates.

[0126] Figure 9 is a graph showing changes in energy density according to an increase in the number of charge and discharge cycles of a lithium-sulfur battery discharged at different current rates.

[0127] Figure 10 is a graph showing changes in coulombic efficiency according to an increase in the number of charge and discharge cycles of a lithium-sulfur battery discharged at different current rates.

[0128] exist Figures 8 to 10 , “Case 1” is a case where a cycle of charging a lithium-sulfur battery at 0.2 [C] and discharging the same battery at 0.1 [C] is repeated, “Case 2” is a case where a cycle of charging a lithium-sulfur battery at 0.2 [C] and discharging the same battery at 0.3 [C] is repeated, and “Case 3” is a case where a cycle of charging a lithium-sulfur battery at 0.2 [C] and discharging the same battery at 0.5 [C] is repeated.

[0129] like Figures 8 to 10 As shown, it can be seen that when the current rate during charge is the same, the discharge efficiency, energy density and coulombic efficiency of the lithium-sulfur battery change steadily as the current rate during discharge is high, although the number of cycles increases.

[0130] Therefore, in the present disclosure, when the SOC of the battery to be discharged is relatively high, the batteries are discharged at a relatively low current rate for self-discharge. At the same time, when the SOC of the battery to be discharged is relatively low, the batteries are discharged alternately at a relatively high current rate.

[0131] Figure 11 is a graph showing changes in discharge capacity per unit weight according to an increase in the number of charge / discharge cycles of lithium-sulfur batteries discharged by different methods.

[0132] Figure 12 is a graph showing changes in energy density according to an increase in the number of charge / discharge cycles of lithium-sulfur batteries discharged by different methods.

[0133] Figure 13 is a graph showing changes in coulombic efficiency according to an increase in the number of charge / discharge cycles of lithium-sulfur batteries discharged by different methods.

[0134] exist Figures 11 to 13 In the present disclosure, a method is provided, wherein when the SOC of each of the plurality of lithium-sulfur batteries is equal to or greater than 75%, the plurality of lithium-sulfur batteries are connected in parallel to each other and discharged simultaneously at 0.1 [C], and when the SOC of each of the plurality of lithium-sulfur batteries becomes lower than 75%, the plurality of lithium-sulfur batteries are alternately discharged at 0.3 [C].

[0135] “Comparative Example 1” relates to a method of fully discharging a plurality of lithium-sulfur batteries sequentially one by one without considering the SOC.

[0136] “Comparative Example 2” relates to a method in which, when the SOC of each of the plurality of lithium-sulfur batteries is equal to or greater than 75%, a plurality of lithium-sulfur batteries are connected in parallel to each other and the batteries are simultaneously discharged at 0.1 [C], and when the SOC of each of the plurality of lithium-sulfur batteries becomes lower than 75%, the plurality of lithium-sulfur batteries are sequentially fully discharged one by one at 0.3 [C].

[0137] like Figures 11 to 13 As shown, it can be seen that compared with the method according to Comparative Example 1 or Comparative Example 2, the method according to the "present disclosure" can improve the discharge efficiency, energy density and coulombic efficiency of the lithium-sulfur battery.

[0138] Figure 14 is a view showing a battery system 10 according to an embodiment of the present disclosure.

[0139] like Figure 14 As shown, a battery system 10 may include a battery pack BG including a plurality of individually rechargeable batteries B1 to Bn, an output terminal BT, and a battery control device 100 according to the present disclosure. The battery pack BG includes a plurality of individually rechargeable batteries B1 to Bn, and the discharge current of the battery pack BG is output to the output terminal BT. In an embodiment, the battery system 10 may further include at least one of a measuring device 12, a charging device 14, and a communication device 16.

[0140] The measuring device 12 may be configured to measure the voltage, charging current, and / or discharging current of the plurality of batteries B1 to Bn. To this end, the measuring device 12 may include at least one electrical sensor.

[0141] For example, the measuring device 12 may include at least one voltage sensor that senses the voltage of the plurality of batteries B1 to Bn and / or at least one current sensor that senses the current of the plurality of batteries B1 to Bn.

[0142] The battery control device 100 according to an embodiment of the present disclosure may acquire voltage values ​​of the plurality of batteries B1 to Bn via the measuring device 12 .

[0143] The charging device 14 may be configured to charge the plurality of batteries B1 to Bn. In this case, the battery control device 100 according to an embodiment of the present disclosure may be configured to control the operation of the charging device 14 to continue or stop charging the plurality of batteries B1 to Bn or change charging conditions.

[0144] The communication unit 16 may be configured to communicate with other remotely located devices. For example, the communication unit 16 may be configured to receive data transmitted from a remote server or communication terminal via a wired and / or wireless communication network and transmit the data to the battery control device 100, or to transmit data generated by the battery control device 100 to another server or communication terminal. To this end, the communication unit 16 may include a communication modem that performs wired and / or wireless communication.

[0145] Figure 15 2 is a diagram illustrating a vehicle 2 according to an embodiment of the present disclosure.

[0146] like Figure 15 As shown, a vehicle 2 according to an embodiment of the present disclosure may include a battery system 10 that provides electrical energy required for operation of the vehicle 2 and a battery control device 100 according to the present disclosure.

[0147] In an embodiment, the battery control device 100 according to the present disclosure may be configured to operate in cooperation or integration with an electronic control unit (ECU) that controls operations of the vehicle 2 or a battery management system (BMS) of the battery system 10 .

[0148] Furthermore, the battery control device 100 may be configured to receive data transmitted from the remote server 4 via a wired and / or wireless communication network, or to transmit data generated by the battery control device 100 to the server 4 .

[0149] Although Figure 15 A vehicle is shown as the transportation tool 2 according to the present disclosure, but the transportation tool 2 according to the present disclosure may be implemented as an aircraft or a watercraft.

[0150] For reference, the battery control device 100 according to the present disclosure may be applied to various electric devices or systems in addition to vehicles such as vehicles, aircraft, and ships, and may also be applied to energy storage systems (ESS).

[0151] As described above, in the present disclosure, during a first discharge period in which the SOC of each of a plurality of batteries is equal to or greater than a predetermined reference value, the plurality of batteries are connected in parallel to one another at the output terminal and are discharged together, so that performance degradation of batteries that rapidly self-discharge when left idle in a high SOC state can be prevented, and errors in estimated SOC values ​​associated with the batteries are reduced.

[0152] Furthermore, in the present disclosure, during the second discharge period in which the SOC of each of the plurality of batteries falls below a reference value, the plurality of batteries are alternately connected to the output terminal and discharged, so that each battery is not continuously discharged after a predetermined reference time has elapsed. Thus, it is possible to improve the discharge capacity per unit weight, energy density, and coulombic efficiency of a battery system including the plurality of batteries, and prevent accidents caused by overheating.

[0153] Furthermore, the present disclosure controls the increase in voltage differences among multiple batteries during discharge, thereby preventing an inrush current from occurring when batteries with large voltage differences are connected in parallel. This prevents damage to the batteries, improves safety, and allows multiple batteries to be charged simultaneously, reducing charging time.

[0154] Furthermore, in the present disclosure, the lithium-sulfur battery can be applied to a battery system requiring high capacity, so that the energy density and safety of the battery system can be improved and the manufacturing cost can be reduced.

[0155] Furthermore, the embodiments of the present disclosure can solve other various technical problems other than those described herein that occur not only in the technical field to which the present disclosure pertains but also in related technical fields.

[0156] The technology of the present disclosure has been described with reference to specific embodiments. However, it will be apparent to those skilled in the art that various modifications can be implemented within the technical scope of the present disclosure. Therefore, the foregoing embodiments should be considered from a descriptive point of view rather than from a restrictive point of view. That is, the substantial scope of the technical concept of the present disclosure can be found in the appended claims, and any differences that fall within the equivalent scope of the present disclosure should be interpreted as being included in the present disclosure.

[0157] (Explanation of Reference Signs)

[0158] 2: Transportation

[0159] 10: Battery system

[0160] 100: Battery control equipment

[0161] 110: Connection unit

[0162] 120: Control unit

[0163] 122: Data acquisition module

[0164] 124: SOC information generation module

[0165] 126: Connecting to the control module

[0166] 130: Storage unit

Claims

1. A battery control device for controlling the discharge of a plurality of batteries, the battery control device comprising: a connector configured to connect or disconnect, for each of the plurality of batteries, a connection between the plurality of batteries and an output terminal to which a discharge current is output; a controller configured to control the connector so that the plurality of batteries are connected to the output terminal in parallel with each other and discharged during a first discharge period, and are alternately connected to the output terminal and discharged during a second discharge period, the first discharge period being from a start time of discharging of the plurality of batteries when the SOC of each battery is equal to or greater than a predetermined reference value until the SOC of at least one battery among the plurality of batteries reaches the reference value, and the second discharge period being from a time when the SOC of each battery among the plurality of batteries becomes lower than the reference value until the discharging of the plurality of batteries is terminated.

2. The battery control device according to claim 1, wherein: The connector includes a plurality of switches corresponding to the plurality of batteries, respectively.

3. The battery control device according to claim 1, wherein: The controller is configured to discharge each of the plurality of batteries at a first current rate during the first discharge period, and to discharge a battery connected to the output terminal among the plurality of batteries at a second current rate higher than the first current rate during the second discharge period.

4. The battery control device according to claim 1, wherein: The controller is configured to switch a battery, among the plurality of batteries, disconnected from the output terminal, into an idle state during the second discharge period.

5. The battery control device according to claim 1, wherein: The controller is configured such that, during the second discharging period, when a connection time of a first battery connected to the output terminal exceeds a predetermined reference time, a second battery selected from remaining batteries excluding the first battery among the plurality of batteries is connected to the output terminal, and the connection of the first battery is cut off.

6. The battery control device according to claim 5, wherein: The second battery is a battery having the highest voltage among the remaining batteries.

7. The battery control device according to claim 5, wherein: The second battery is a battery that is disconnected from the output terminal for the longest period of time among the remaining batteries.

8. The battery control device according to claim 1, wherein: The controller includes: a data acquisition module configured to acquire data on electrical characteristic values ​​of the plurality of batteries using at least one electrical sensor; an SOC information generating module configured to generate SOC information indicating an SOC value of each of the plurality of batteries using the data; and A connection control module is configured to control the connector according to SOC values ​​of the plurality of batteries indicated in the SOC information.

9. The battery control device according to claim 1, wherein: The plurality of batteries includes at least one lithium-sulfur battery. 10 . A battery system comprising the battery control device according to claim 1 .

11. A vehicle comprising the battery control device according to any one of claims 1 to 9.

12. A battery control method for controlling discharge of a plurality of batteries, the battery control method comprising: a first discharging step in which the plurality of batteries are connected to an output terminal in parallel with one another and are discharged during a first discharging period, the first discharging period being a time from a start time of discharging of the plurality of batteries when the SOC of each battery is equal to or greater than a predetermined reference value until the SOC of at least one battery among the plurality of batteries reaches the reference value; as well as a second discharging step in which the plurality of batteries are alternately connected to the output terminal and discharged during a second discharging period, the second discharging period being a time from when the SOC of each of the plurality of batteries becomes lower than the reference value until the discharging of the plurality of batteries is terminated.

13. The battery control method according to claim 12, wherein: In the first discharging step, each battery in the plurality of batteries is discharged at a first current rate, and In the second discharging step, a battery connected to the output terminal among the plurality of batteries is discharged at a second current rate higher than the first current rate during the second discharging period.

14. The battery control method according to claim 12, wherein: In the second discharging step, a battery disconnected from the output terminal among the plurality of batteries is switched to enter an idle state.

15. The battery control method according to claim 12, wherein: In the second discharging step, when a connection time of a first battery connected to the output terminal exceeds a predetermined reference time, a second battery selected from remaining batteries excluding the first battery among the plurality of batteries is connected to the output terminal, and the connection of the first battery is cut off.

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