Battery output prediction method and battery system providing the same

Abstract

The present invention relates to a method for predicting the charging output and discharging output of a battery and a battery system providing such a method, and the battery system of the present invention includes a battery including a plurality of battery modules each including a plurality of battery cells, and a main control circuit that determines a representative temperature corresponding to the temperature of the battery based on a plurality of module temperatures which are the temperatures of each of the plurality of battery modules, a coolant temperature which is the temperature of coolant flowing between the plurality of battery modules, and the atmospheric temperature, and predicts an output value of the battery based on the determined representative temperature and a state of charge (SOC) of the battery determined according to a predetermined criterion.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0183568 dated December 23, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a method for predicting the charging and discharging power of a battery and a battery system providing the method. [Background technology]

[0003] One of the key technologies in battery development is the battery output during charging or discharging. In particular, battery output is a very important factor when planning the operation of a system in which a battery is installed.

[0004] The magnitude of the battery output is closely related to the temperature of the battery. For example, when the external atmospheric temperature is high, a maximum cell temperature having a maximum value among the cell temperatures of each of the battery cells may be extracted, and the maximum output of the battery may be predicted based on the extracted maximum cell temperature. As another example, when the external atmospheric temperature is low, a minimum cell temperature having a minimum value among the cell temperatures of each of the battery cells may be extracted, and the maximum output of the battery may be predicted based on the extracted minimum cell temperature.

[0005] However, in the conventional method of predicting the output of a battery, a device such as a temperature sensor must be installed in each of the battery cells to measure the cell temperature. Also, in the conventional method, the process of determining a cell temperature representative of the battery temperature based on the measured cell temperatures is complicated. In other words, the conventional method has a problem of cost incurred due to the purchase of multiple temperature sensors and a burden of requiring a separate process for determining the battery temperature. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides a battery system and a method for predicting battery output that accurately predict the output of a battery based on the cell temperatures of some of a plurality of battery cells that constitute the battery. [Means for solving the problem]

[0007] A battery system according to one feature of the present invention includes a battery including a plurality of battery modules, each of which includes a plurality of battery cells; and a main control circuit that determines a representative temperature corresponding to the temperature of the battery based on a plurality of module temperatures, which are the temperatures of each of the plurality of battery modules, a coolant temperature, which is the temperature of coolant flowing between the plurality of battery modules, and an atmospheric temperature, and predicts an output value of the battery based on the determined representative temperature and a state of charge (SOC) of the battery determined according to a predetermined criterion.

[0008] The main control circuit can determine the maximum value of the multiple module temperatures as the representative temperature if the multiple module temperatures fall within an average temperature range corresponding to exceeding a predetermined first reference temperature and being below a predetermined second reference temperature.

[0009] When the plurality of module temperatures exceed the average temperature range and the atmospheric temperature is equal to or higher than the cooling water temperature, the main control circuit can determine the maximum value of the plurality of module temperatures as the representative temperature.

[0010] The main control circuit may determine a minimum value of the module temperatures as the representative temperature if the module temperatures exceed the average temperature range and the atmospheric temperature is lower than the cooling water temperature.

[0011] The main control circuit can correct the predicted output value by reducing it based on a predetermined standard if the representative temperature falls within an extreme temperature range corresponding to being below a minimum reference temperature, which is a predetermined temperature lower than the first reference temperature, and exceeding a maximum reference temperature, which is a predetermined temperature higher than the second reference temperature.

[0012] Each of the plurality of battery modules includes a reference cell which is a battery cell among the plurality of battery cells located within a predetermined range based on an outlet of a cooling water plate through which the cooling water flows, and a module temperature of each of the plurality of battery modules can correspond to a cell temperature of the reference cell.

[0013] Each of the plurality of battery cells is configured in a columnar shape including a lower surface located close to the coolant, an upper surface facing the lower surface at a predetermined distance, and a side surface connecting the lower surface and the upper surface, and when the lower surface is cooled, the temperature of the upper surface becomes a maximum value, and when the lower surface is heated, the temperature of the upper surface becomes a minimum value.

[0014] The cell temperature of the reference cell may correspond to a temperature measured at a top surface of the reference cell.

[0015] According to another aspect of the present invention, a method for predicting output of a battery including a plurality of battery modules each including a plurality of battery cells includes the steps of receiving a plurality of module temperatures, which are temperatures of each of the plurality of battery modules; determining a representative temperature corresponding to the temperature of the battery based on the plurality of module temperatures, a coolant temperature, which is a temperature of coolant flowing between the plurality of battery modules, and an atmospheric temperature; and predicting an output value of the battery based on the determined representative temperature and a State of Charge (SOC) of the battery determined according to a predetermined criterion.

[0016] The step of determining the representative temperature may include a step of determining whether the plurality of module temperatures fall within an average temperature range corresponding to exceeding a predetermined first reference temperature and being below a predetermined second reference temperature, and a first temperature determination step of determining a maximum value among the plurality of module temperatures as the representative temperature if the plurality of module temperatures fall within the average temperature range as a result of the determination.

[0017] The step of determining the representative temperature may further include a step of determining whether the atmospheric temperature is lower than the cooling water temperature if the determination result indicates that the plurality of module temperatures do not fall within the average temperature range, and a second temperature determination step of determining a minimum value of the plurality of module temperatures as the representative temperature if the determination result indicates that the atmospheric temperature is lower than the cooling water temperature, and the first temperature determination step may be performed if the determination result indicates that the atmospheric temperature is higher than or equal to the cooling water temperature.

[0018] The output prediction method may further include, after the step of predicting an output value of the battery, a step of determining whether the representative temperature falls within an extreme temperature range corresponding to being below a minimum reference temperature that is a predetermined temperature lower than the first reference temperature and being above a maximum reference temperature that is a predetermined temperature higher than the second reference temperature; if the representative temperature falls within the extreme temperature range as a result of the determination, a step of reducing and correcting the predicted output value according to a predetermined criterion; and if the representative temperature does not fall within the extreme temperature range as a result of the determination, a step of determining the predicted output value as the output of the battery. Effect of the Invention

[0019] The present invention can reduce manufacturing costs by reducing the number of temperature sensors required to measure the temperature of the battery.

[0020] The present invention can predict the output of the entire battery based on the cell temperatures of some of the battery cells, but can reliably predict the output of the battery by using a battery temperature determination process that takes into account the external atmospheric temperature and the coolant temperature. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a diagram illustrating a battery system according to an embodiment. [Diagram 2] 2 is an exemplary diagram illustrating one type of battery cell constituting the battery of FIG. 1. FIG. [Diagram 3] 1. FIG. 4 is an exemplary diagram illustrating another type of battery cell that constitutes the battery of FIG. [Figure 4] 3 is a diagram for explaining the characteristics of the cylindrical battery cell of FIG. 2. [Diagram 5] 3 is a diagram for explaining the characteristics of the cylindrical battery cell of FIG. 2. [Figure 6] FIG. 2 is an exemplary diagram illustrating the structure of the battery in FIG. [Figure 7] FIG. 7 is a diagram illustrating a cross section of the battery in FIG. 6. [Figure 8] FIG. 7 is a diagram illustrating an example in which two battery modules that constitute the battery in FIG. 6 are located on the upper and lower surfaces of one cooling plate CP. [Figure 9] FIG. 9 is a diagram for explaining the structure of the cooling plate shown in FIGS. 6 to 8. [Figure 10] 10A and 10B are diagrams illustrating the temperature of the coolant flowing through the cooling plate, the atmospheric temperature, and the temperature of the battery cell depending on the position on the cooling plate. [Figure 11] 10A and 10B are diagrams illustrating the temperature of the coolant flowing through the cooling plate, the atmospheric temperature, and the temperature of the battery cell depending on the position on the cooling plate. [Figure 12] 8 is a diagram for explaining the position of a reference cell in the first battery module M1 in FIG. 7. FIG. [Figure 13] 8 is a diagram for explaining the position of a reference cell in the second battery module M2 in FIG. 7. FIG. [Figure 14] 8 is a diagram for explaining the position of a reference cell in the third battery module M3 in FIG. 7. FIG. [Figure 15] 8 is a diagram for explaining the position of a reference cell in the fourth battery module M4 in FIG. 7. FIG. [Figure 16]1 is a flowchart illustrating a method for predicting battery output according to an embodiment. [Figure 17] FIG. 17 is an illustrative diagram for explaining the concept of maximum temperature and minimum temperature in FIG. 16. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, the embodiments disclosed herein will be described in detail with reference to the attached drawings, and the same or similar components will be given the same or similar drawing numbers, and duplicated descriptions thereof will be omitted. The suffixes "module" and / or "part" for components used in the following description are given or mixed for the sake of ease of specification writing only, and do not have any meaning or role that is different from each other by themselves. In addition, when describing the embodiments disclosed herein, if it is determined that a specific description of such known technology may obscure the gist of the embodiments disclosed herein, the detailed description will be omitted. Furthermore, the attached drawings are merely for the purpose of making the embodiments disclosed herein easily understandable, and it should be understood that the attached drawings do not limit the technical ideas disclosed herein, and include all modifications, equivalents, or alternatives included in the ideas and technical scope of the present invention.

[0023] Terms including ordinal numbers such as first, second, etc. may be used to describe various components, but the components are not limited by the terms. The terms are used only to distinguish one component from another.

[0024] When a component is referred to as being "coupled" or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but that there may be other components in between. In contrast, when a component is referred to as being "directly coupled" or "directly connected" to another component, it should be understood that there are no other components in between.

[0025] It should be understood that in this application, terms such as "comprise" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0026] FIG. 1 is a diagram illustrating a battery system according to an embodiment.

[0027] Referring to FIG. 1, a battery system 1 includes a battery 10, a relay 20, and a battery management system (hereinafter, referred to as BMS) 30.

[0028] 1, the upper system 2 may be a system in which the battery system 1 is mounted and which is operated by being supplied with power from the battery 10. For example, the upper system 2 may include an automobile system, an energy storage system (ESS), etc.

[0029] A battery 10 is connected between two output terminals OUT1 and OUT2 of the battery system 1, a relay 20 is connected between the positive terminal of the battery system 1 and the first output terminal OUT1, and a current sensor (not shown) can be connected between the negative terminal of the battery system 1 and the second output terminal OUT2. The configurations and the connections between the configurations shown in FIG. 1 are merely examples, and the invention is not limited thereto.

[0030] The battery 10 may include a plurality of battery modules M, each of which includes a plurality of battery cells Cell1-Celln electrically connected in series and in parallel. In an embodiment, the battery cells may be rechargeable secondary batteries. A predetermined number of battery cells may be connected in series and / or in parallel to form a battery module, and a predetermined number of battery modules may be connected in series and / or in parallel to form the battery 10.

[0031] The relay 20 controls an electrical connection between the battery system 1 and an external device. When the relay 20 is turned on, the battery system 1 and the external device are electrically connected to each other to perform charging or discharging, and when the relay 20 is turned off, the battery system 1 and the external device are electrically separated from each other. At this time, the external device may be a charger in a charging cycle in which the battery 10 is charged by supplying power thereto, and may be a load (e.g., a motor, etc.) in a discharging cycle in which the battery 10 discharges power to the external device.

[0032] The BMS 30 includes a monitoring unit 31 and a main control circuit 33 .

[0033] The monitoring unit 31 can collect a plurality of module temperatures, which are the temperatures of the plurality of battery modules M1-Mn, and transmit the collected plurality of module temperatures to the main control circuit 33.

[0034] The module temperature (MT) is the temperature of the battery module. In some embodiments, the module temperature MT may correspond to the cell temperature (CT) of a battery cell (hereinafter, a reference cell) determined according to a predetermined criterion among a plurality of battery cells Cell1-Celln constituting the battery module M. At this time, a method of determining the reference cell will be described in detail with reference to FIG. 2 to FIG. 14.

[0035] The main control circuit 33 can determine a representative temperature corresponding to the temperature of the battery 10 based on the multiple module temperatures, the coolant temperature which is the temperature of the coolant flowing between the multiple battery modules M1-Mn, and the atmospheric temperature. The main control circuit 33 can also predict the output of the battery 10 based on the representative temperature and the state of charge (SOC) of the battery 10. At this time, the output of the battery 10 may be a charging output or a discharging output, and is expressed as a numerical value.

[0036] 1, for example, the main control circuit 33 may receive information regarding the coolant temperature and the atmospheric temperature by communicating with the upper system 2 in which the battery system 1 is mounted. As another example, the main control circuit 33 may receive information regarding the coolant temperature and the atmospheric temperature directly from various temperature sensors (not shown) mounted in the upper system 2. However, the present invention is not limited to this, and the main control circuit 33 may collect information regarding the coolant temperature and the atmospheric temperature in various ways.

[0037] The following Table 1 is an example of a look-up table including the charge output power (COP) of the battery 10 according to the battery temperature and state of charge (SOC).

[0038] [Table 1]

[0039] The main control circuit 33 can predict the charging output of the battery 10 by matching the battery temperature and state of charge (SOC) to the Table 1. According to the embodiment, the battery temperature disclosed in the Table 1 can correspond to a representative temperature calculated based on a plurality of module temperatures, a coolant temperature, and an atmospheric temperature.

[0040] Table 2 below is an example of a look-up table including the discharge output power (DOP) of the battery 10 according to the temperature and state of charge (SOC) of the battery 10.

[0041] [Table 2]

[0042] The main control circuit 33 can predict the discharge output of the battery 10 by matching the temperature and state of charge (SOC) of the battery 10 with Table 2. According to an embodiment, the battery temperature disclosed in Table 2 can correspond to a representative temperature calculated based on a plurality of module temperatures, a coolant temperature, and an atmospheric temperature.

[0043] Conventionally, in order to collect the temperature of the battery 10, a number of temperature sensors corresponding to the total number of battery cells constituting the battery 10 was required. In addition, the conventional BMS 30 performed a complicated process of determining the temperature of the battery 10 based on the measured cell temperatures of all the battery cells.

[0044] According to the embodiment, the monitoring unit 31 measures only the cell temperature CT of a reference cell that represents the battery module M, and determines the measured cell temperature CT as the module temperature MT. In addition, the main control circuit 33 performs a simple process of determining one of the module temperatures MT of each of the multiple battery modules that constitute the battery 10 as a representative temperature that is the temperature of the battery 10. Then, the temperature of the battery 10 can be determined based on only the number of temperature sensors corresponding to the number of battery modules M.

[0045] A method for determining a reference cell that represents the battery module M based on the structural and positional characteristics of the battery cell will be described in detail below.

[0046] FIG. 2 is an illustrative diagram for explaining one type of battery cell constituting the battery of FIG. 1, FIG. 3 is an illustrative diagram for explaining another type of battery cell constituting the battery of FIG. 1, and FIGS. 4 and 5 are diagrams for explaining the characteristics of the cylindrical battery cell of FIG. 2.

[0047] Referring to FIG. 2, as an example, the battery cell is configured in a small cylindrical shape. For example, the specifications of a cylindrical battery cell used in an electric vehicle are 21 mm in diameter at the top and bottom, and 70 mm in height. Referring to FIG. 3, as another example, the battery cell may be configured in a large pouch shape. For example, the specifications of a pouch-shaped battery cell used in an electric vehicle are 590 mm in width and 100 mm in height.

[0048] 2 and 3, compared to a pouch-shaped battery cell, a cylindrical battery cell has a very small cross-section to be heated or cooled, and the temperature distribution within the cross-section is almost the same. Also, the cylindrical battery cell has a constant temperature change according to the height.

[0049] For example, referring to Fig. 4, when the bottom surface Cell_BOT of the cylindrical battery cell of Fig. 2 is cooled, the temperature of the top surface Cell_TOP of all the surfaces constituting the battery cell is the highest (CellT_MAX). Referring to Fig. 5, as another example, when the bottom surface Cell_BOT of the cylindrical battery cell of Fig. 2 is heated, the temperature of the top surface Cell_TOP of all the surfaces constituting the battery cell is the lowest (CellT_MIN).

[0050] According to an embodiment, the battery cells constituting the battery 10 and the battery module may be cylindrical battery cells as described in FIGS. 2, 4, and 5. According to an embodiment, the battery cell is configured in a columnar shape including a lower surface Cell_BOT located close to the cooling water, an upper surface Cell_TOP facing the lower surface Cell_BOT at a predetermined distance, and a side surface Cell_SIDE connecting the lower surface Cell_BOT and the upper surface Cell_TOP. However, the present invention is not limited thereto, and the battery 10 can be configured regardless of its shape as long as the battery cell has the highest temperature of the upper surface Cell_TOP when the lower surface Cell_BOT is cooled and the lowest temperature of the upper surface Cell_TOP when the lower surface Cell_BOT is heated.

[0051] The structure of the battery 10 including a plurality of battery modules, each of which includes a plurality of battery cells, will be described in detail below.

[0052] FIG. 6 is an illustrative diagram explaining the structure of the battery of FIG. 1, FIG. 7 is a diagram explaining a cross-section of the battery of FIG. 6, and FIG. 8 is a diagram explaining an example in which two battery modules constituting the battery of FIG. 6 are located on the upper and lower surfaces of a single cooling plate CP.

[0053] The battery 10 may include at least one battery pack including a plurality of battery modules M including a plurality of battery cells Cell1_Celln. For example, the battery 10 may include at least one battery pack as shown in FIG. 6. Hereinafter, the battery 10 will be described as including one battery pack, but is not limited thereto, and may include a plurality of battery packs as shown in FIG. 6. In this case, the number of module temperatures required in the method of calculating the representative temperature described below may increase, but the basic calculation method is equally applicable.

[0054] Referring to Figures 6 and 7, for example, the battery 10 has four battery modules M1, M2, M3, and M4 located on the upper and lower surfaces of two cooling plates CP_T and CP_B, respectively, and each of the four battery modules M1, M2, M3, and M4 may include a plurality of battery cells Cell1_Celln connected in parallel.

[0055] The cooling plate CP may be a plate through which coolant, which is a liquid that cools the heat of the battery cells, flows. According to an embodiment, the battery 10 may include two cooling plates CP, which may be classified into an upper cooling plate CP_T and a lower cooling plate CP_B according to their positions. Referring to FIG. 6 and FIG. 7, the first battery module M1 may be located at an upper portion TT of the upper cooling plate CP_T, and the second battery module M2 may be located at a lower portion TB of the upper cooling plate CP_T. At this time, the lower surfaces Cell_BOT of the plurality of battery cells included in each of the first battery module M1 and the second battery module M2 may be located so as to be adjacent to or in contact with the upper cooling plate CP_T. In addition, the third battery module M3 may be located at an upper portion BT of the lower cooling plate CP_B, and the fourth battery module M4 may be located at a lower portion BB of the lower cooling plate CP_B. At this time, the lower surfaces Cell_BOT of the plurality of battery cells included in each of the third battery module M3 and the fourth battery module M4 may be located so as to be adjacent to or in contact with the lower cooling plate CP_B. Referring to FIG. 8, the upper cooling plate CP_T and the lower cooling plate CP_B may have battery modules located above and below the cooling plate CP, respectively.

[0056] A method for determining a reference cell that represents the battery module M based on the positional characteristics of the battery cells will be described in detail below.

[0057] FIG. 9 is a diagram explaining the structure of the cooling plate shown in FIG. 6 to FIG. 8, and FIG. 10 and FIG. 11 are diagrams explaining the temperature of the cooling water flowing through the cooling plate, the atmospheric temperature, and the temperature of the battery cells depending on the position of the cooling plate.

[0058] Referring to FIG. 9, the cooling plate CP may include an inlet through which cooling water (CW) flows and an outlet through which the cooling water flows out. In addition, a flow path is formed in the cooling plate CP by a plurality of partition walls. The cooling water CW flows along the flow path and exchanges heat with a plurality of battery cells in contact with the cooling plate CP. That is, the cooling water CW can absorb heat from the plurality of battery cells to reduce the temperature of the plurality of battery cells. Therefore, as the cooling water CW flows along the flow path, the temperature of the cooling water CW gradually increases. In summary, the temperature of the cooling water CW is lowest at a position A close to the inlet and highest at a position B close to the outlet. Hereinafter, the temperature of the cooling water CW will be described as the cooling water temperature.

[0059] Referring to FIG. 10, for example, it is assumed that the air temperature is 25° C., the coolant temperature is 10° C., and the temperature of the battery cell corresponds to the air temperature. In this environment, referring to FIG. 6 and FIG. 8, while the coolant CW flows along the flow path, the coolant CW is heated by the atmosphere. That is, as the travel time and / or travel distance of the coolant CW increases, the temperature of the coolant CW gradually increases. For example, when the coolant temperature at the inlet is 10° C., the coolant temperature at the outlet is 12° C., 13° C., 14° C., etc. In FIG. 10, it is assumed that the coolant temperature at a position close to the outlet is 12° C.

[0060] In FIG. 10, the temperature of the battery cell is higher than the coolant temperature, so the lower surface of the battery cell is cooled by the coolant CW. Also, since the lower surface of the battery cell is in contact with (or close to) the cooling plate CP, the temperature of the lower surface of the battery cell is the same as the coolant temperature within a certain error range. For example, the lower surface of the battery cell Cell_A at position A close to the inlet is cooled by the coolant, so that the temperature of the lower surface of the battery cell Cell_A is 10°C, which is the same as the coolant temperature (10°C). The lower surface of the battery cell Cell_B at position B close to the outlet is cooled by the coolant, so that the temperature of the lower surface of the battery cell Cell_B is 12°C, which is the same as the coolant temperature (12°C). As previously described in FIG. 4, when the lower surface is cooled, the temperature of the upper surface is higher than the temperature of the lower surface. For example, if it is assumed that the temperature difference between the upper and lower surfaces is about 1°C depending on the characteristics of the battery cells, the temperature of the upper surface of battery cell Cell_A is about 11°C, and the temperature of the upper surface of battery cell Cell_B is about 13°C.

[0061] 10, when the air temperature is higher than the coolant temperature, the temperature of the battery cell Cell_B located close to the outlet among the battery cells in contact with (or close to) the cooling plate CP is the highest. In particular, the temperature of the upper surface of the battery cell Cell_B is the highest.

[0062] Referring to FIG. 11, for example, it is assumed that the air temperature is 5° C., the coolant temperature is 10° C., and the temperature of the battery cell corresponds to the air temperature. In this environment, referring to FIG. 6 and FIG. 8, while the coolant CW flows along the flow path, the coolant CW is cooled by the atmosphere. That is, as the travel time and / or travel distance of the coolant CW increases, the temperature of the coolant CW gradually decreases. For example, when the coolant temperature at the inlet is 10° C., the coolant temperature at the outlet is 8° C., 7° C., 6° C., etc. In FIG. 11, it is assumed that the coolant temperature at a position close to the outlet is 8° C.

[0063] In FIG. 11, since the temperature of the battery cell is lower than the coolant temperature, the lower surface of the battery cell is heated by the coolant CW. Also, since the lower surface of the battery cell is in contact with (or close to) the cooling plate CP, the temperature of the lower surface of the battery cell is the same as the coolant temperature within a certain error range. For example, the temperature of the lower surface of the battery cell Cell_A at position A close to the inlet is 10°C, which is the same as the coolant temperature (10°C). The temperature of the lower surface of the battery cell Cell_B at position B close to the outlet is 8°C, which is the same as the coolant temperature (8°C). As previously described in FIG. 5, when the lower surface is heated, the temperature of the upper surface is lower than the temperature of the lower surface. For example, assuming that the temperature difference between the upper surface and the lower surface is about 1°C due to the characteristics of the battery cell, the temperature of the upper surface of the battery cell Cell_A is about 9°C, and the temperature of the upper surface of the battery cell Cell_B is about 7°C.

[0064] 11, when the air temperature is lower than the coolant temperature, the temperature of the battery cell Cell_B located closest to the outlet among the battery cells in contact with (or close to) the cooling plate CP is the lowest. In particular, the temperature of the upper surface of the battery cell Cell_B is the lowest.

[0065] In summary, if the atmospheric temperature is higher than the coolant temperature, the temperature of the battery cell Cell_B located close to the outlet of the cooling plate CP among the multiple battery cells constituting the battery module is the highest. Also, if the atmospheric temperature is lower than the coolant temperature, the temperature of the battery cell Cell_B located close to the outlet of the cooling plate CP among the multiple battery cells constituting the battery module is the lowest. In other words, when the atmospheric temperature and the coolant temperature are known, the maximum or minimum temperature in the battery module can be predicted only from the temperature of the battery cell Cell_B located close to the outlet of the cooling plate CP. The method for predicting the maximum or minimum temperature in the battery module can be equally applied to the multiple battery modules M1, M2, M3, and M4 constituting the battery pack.

[0066] 12 to 15 are diagrams illustrating the positions of the reference cells in each of the first to fourth battery modules M1, M2, M3, and M4 in FIG.

[0067] As previously described with reference to FIGS. 4 to 11, the maximum or minimum temperature within the battery module can be predicted based only on the temperature of the battery cell Cell_B located adjacent to the outlet of the cooling plate CP.

[0068] In the embodiment, in each of the battery modules M1, M2, M3, and M4, a battery cell Cell_B located close to an outlet of a cooling plate CP is defined as a reference cell representing the battery module. In other words, the reference cell may be a battery cell located within a predetermined distance from the outlet of the cooling plate CP among the battery cells constituting the battery module.

[0069] Referring to Figs. 6, 7, and 12, the reference cell TT_Cell_B of the first battery module M1 may be located close to the outlet of the cooling plate CP from the upper part TT of the upper cooling plate CP_T. Referring to Figs. 6, 7, and 13, the reference cell TB_Cell_B of the second battery module M2 may be located close to the outlet of the cooling plate CP from the lower part TB of the upper cooling plate CP_T. Referring to Figs. 6, 7, and 14, the reference cell BT_Cell_B of the third battery module M3 may be located close to the outlet of the cooling plate CP from the upper part BT of the lower cooling plate CP_B. Referring to Figs. 6, 7, and 15, the reference cell BB_Cell_B of the fourth battery module M4 may be located close to the outlet of the cooling plate CP from the lower part BB of the lower cooling plate CP_B.

[0070] According to an embodiment, the module temperature of each of the plurality of battery modules M1, M2, M3, M4 can correspond to the temperature of a respective reference cell. According to another embodiment, the module temperature of each of the plurality of battery modules M1, M2, M3, M4 can correspond to the temperature measured at a top surface of a respective reference cell.

[0071] FIG. 16 is a flow chart illustrating a method for predicting the output of a battery according to an embodiment, and FIG. 17 is an example diagram illustrating the concept of maximum and minimum temperatures in FIG.

[0072] A battery output prediction method and a battery system that provides the method will be described with reference to FIGS. 1 to 17. FIG.

[0073] 16, first, the main control circuit 33 receives information on a plurality of module temperatures, which are the temperatures of the plurality of battery modules M1, M2, M3, and M4, from the monitoring unit 31 (S100).

[0074] The monitoring unit 31 can collect a plurality of module temperatures and transmit information on the collected plurality of module temperatures to the main control circuit 33. The module temperature MT is the temperature of the battery module. In some embodiments, the module temperature MT can correspond to a cell temperature CT of a reference cell among the plurality of battery cells Cell1-Celln constituting the battery module M.

[0075] Next, the main control circuit 33 determines whether a plurality of module temperatures fall within the average temperature range (S200).

[0076] The average temperature range is a temperature range within which the battery 10 can operate normally as predicted according to a preset process. According to an embodiment, the average temperature range can be defined as a temperature range corresponding to exceeding a predetermined first reference temperature and being less than a predetermined second reference temperature. Referring to FIG. 17, for example, the first reference temperature T2 is 10° C. and the second reference temperature T3 is 35° C. However, it is not limited thereto, and the first reference temperature T2 and the second reference temperature T3 can be determined in consideration of various situations such as the structure of the battery 10.

[0077] Next, as a result of the determination, if a plurality of module temperatures belong to the average temperature range (S200, YES), the main control circuit 33 determines the maximum temperature among the plurality of module temperatures as the representative temperature (first representative temperature determination step) (S300).

[0078] When a plurality of module temperatures belong to the average temperature range, the main control circuit 33 determines the maximum temperature among the plurality of module temperatures as the representative temperature. If even one of the plurality of module temperatures does not belong to the average temperature range, the main control circuit 33 executes the following step S400.

[0079] Next, as a result of the determination, if at least one module temperature does not belong to the average temperature range (S200, NO), the main control circuit 33 determines whether the ambient temperature is equal to or higher than the cooling water temperature (S400).

[0080] For example, the main control circuit 33 can communicate with the upper system 2 equipped with the battery system 1 to receive information regarding the cooling water temperature and the ambient temperature. As another example, the main control circuit 33 can directly receive information regarding the cooling water temperature and the ambient temperature from various temperature sensors (not shown) mounted on the upper system 2. However, it is not limited thereto, and the main control circuit 33 can collect information regarding the cooling water temperature and the ambient temperature in various ways.

[0081] Next, if the result of the determination is that the atmospheric temperature is equal to or higher than the cooling water temperature (S400, YES), the main control circuit 33 determines the maximum temperature, which is the maximum value among the multiple module temperatures, as the representative temperature (S300).

[0082] According to an embodiment, the representative temperature may be a temperature corresponding to the temperature of the battery 10. Conventionally, the cell temperatures of all the battery cells constituting the battery 10 are collected, and the maximum or minimum temperature among them is determined as the temperature of the battery 10. However, according to an embodiment, only the module temperatures of the multiple battery modules constituting the battery 10 are collected, and one of the module temperatures among them can be determined as the temperature of the battery 10. Therefore, the battery system and the battery output prediction method according to the embodiment can significantly reduce the number of temperature sensors compared to the conventional method.

[0083] Next, if the result of the determination is that the atmospheric temperature is lower than the cooling water temperature (S400, NO), the main control circuit 33 determines the minimum temperature, which is the minimum value of the multiple module temperatures, as the representative temperature (second representative temperature determination step) (S500).

[0084] Next, the main control circuit 33 predicts the output of the battery 10 based on the representative temperature and the state of charge (SOC) of the battery 10 (S600).

[0085] The main control circuit 33 can predict the output of the battery 10 by various conventionally known algorithms based on the representative temperature and the state of charge (SOC) of the battery 10. For example, the main control circuit 33 can predict the output of the battery 10 by matching the representative temperature and the state of charge (SOC) of the battery 10 with a lookup table.

[0086] Referring to Table 1, the main control circuit 33 can predict the charging output of the battery 10 by matching the representative temperature and the state of charge (SOC) of the battery 10 to the lookup table. For example, assume that the representative temperature is 25° C. and the state of charge (SOC) of the battery 10 is 60%. Then, the main control circuit 33 can predict the charging output of the battery 10 to be 162,942 W.

[0087] Referring to Table 2, the main control circuit 33 can predict the discharge output of the battery 10 by matching the representative temperature and the state of charge (SOC) of the battery 10 to the lookup table. For example, assume that the representative temperature is 25° C. and the state of charge (SOC) of the battery 10 is 60%. Then, the main control circuit 33 can predict the charge output of the battery 10 to be 218,423 W.

[0088] Next, the main control circuit 33 determines whether the representative temperature falls within the extreme temperature range (S700).

[0089] The extreme temperature range is a temperature range in which the battery 10 is difficult to operate normally beyond a range predicted according to a preset process. According to one embodiment, the extreme temperature range may be a temperature range corresponding to a temperature less than a minimum reference temperature T1, which is a predetermined temperature lower than a first reference temperature T2. According to another embodiment, the extreme temperature range may be a temperature range corresponding to a temperature exceeding a maximum reference temperature T4, which is a predetermined temperature higher than a second reference temperature T3. Referring to FIG. 17, for example, the minimum reference temperature T1 is −30° C. and the maximum reference temperature T4 is 50° C. However, the present invention is not limited thereto, and the minimum reference temperature T1 and the maximum reference temperature T4 can be determined in consideration of various circumstances such as the structure of the battery 10.

[0090] Next, if the representative temperature is determined to be within the extreme temperature range (S700, YES), the main control circuit 33 corrects the output of the battery 10 predicted in step S600 (S800).

[0091] According to the embodiment, the main control circuit 33 may perform a correction to reduce the output of the battery 10 predicted in step S600. The main control circuit 33 may correct the output of the battery 10 by multiplying the predicted output of the battery 10 by a correction ratio (α) defined as an integer smaller than 1.

[0092] Referring to Table 1, for example, assume that the representative temperature is -45°C and the state of charge (SOC) of the battery 10 is 60%. Then, the main control circuit 33 can predict the charging output of the battery 10 to be 51,728W. Then, assume that the representative temperature (-45°C) belongs to the extreme temperature range (less than -30°C, more than 50°C) and the correction ratio (α) is 0.5. Then, the main control circuit 33 can multiply the predicted charging output (51,728W) by the correction ratio (0.5) to perform a correction to reduce the output of the battery 10. At this time, the main control circuit 33 can determine the corrected output of the battery 10 (51,728*0.5=25,864W) as the final output of the battery 10.

[0093] Referring to Table 2, for example, assume that the representative temperature is 55° C. and the state of charge (SOC) of the battery 10 is 60%. Then, the main control circuit 33 can predict the charging output of the battery 10 to be 110,348 W. Then, assume that the representative temperature (55° C.) belongs to the extreme temperature range (less than −30° C., more than 50° C.) and the correction ratio (α) is 0.5. Then, the main control circuit 33 can multiply the predicted charging output (110,348 W) by the correction ratio (0.5) to perform a correction to reduce the output of the battery 10. At this time, the main control circuit 33 can determine the corrected output of the battery 10 (110,348×0.5=55,174 W) as the final output of the battery 10.

[0094] Next, if the representative temperature does not fall within the extreme temperature range (S700, NO), the main control circuit 33 determines the output of the battery 10 predicted in step S600 as the final output of the battery 10 (S900).

[0095] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited to these embodiments, and various modifications and improvements made by those having ordinary skill in the art to which the present invention pertains also fall within the scope of the present invention.

Claims

1. A battery having a plurality of battery modules each including a plurality of battery cells, a main control circuit that determines a representative temperature corresponding to the temperature of the battery based on a plurality of module temperatures that are the temperatures of the plurality of battery modules respectively, a cooling water temperature that is the temperature of cooling water flowing between the plurality of battery modules, and an atmospheric temperature, and predicts an output value of the battery based on the determined representative temperature and a state of charge of the battery determined according to a predetermined criterion. A battery system comprising:

2. The main control circuit: When the plurality of module temperatures belong to an average temperature range corresponding to a temperature range that exceeds a predetermined first reference temperature and is less than a predetermined second reference temperature, determines the maximum value among the plurality of module temperatures as the representative temperature. The battery system according to claim 1.

3. The main control circuit: When the plurality of module temperatures exceed the average temperature range and the atmospheric temperature is equal to or higher than the cooling water temperature, determines the maximum value among the plurality of module temperatures as the representative temperature. The battery system according to claim 2.

4. The main control circuit: When the plurality of module temperatures exceed the average temperature range and the atmospheric temperature is lower than the cooling water temperature, determines the minimum value among the plurality of module temperatures as the representative temperature. The battery system according to claim 2.

5. The main control circuit: When the representative temperature belongs to an extreme temperature range corresponding to a temperature range that is lower than a minimum reference temperature by a predetermined temperature lower than the first reference temperature and a temperature range that exceeds a maximum reference temperature by a predetermined temperature higher than the second reference temperature, reduces and corrects the predicted output value according to a predetermined criterion. The battery system according to claim 2.

6. Each of the plurality of battery modules includes: a reference cell that is a battery cell located within a predetermined range with reference to an outlet of a cooling water plate through which the cooling water flows among the plurality of battery cells, and the module temperature of each of the plurality of battery modules: corresponds to the cell temperature of the reference cell. The battery system according to any one of claims 1 to 5.

7. Each of the plurality of battery cells: is configured in a columnar shape including a lower surface located close to the cooling water, an upper surface facing the lower surface at a predetermined interval, and side surfaces connecting the lower surface and the upper surface.

7. The battery system of claim 6, wherein the temperature of the upper surface is at a maximum value when the lower surface is cooled and the temperature of the upper surface is at a minimum value when the lower surface is heated.

8. The cell temperature of the reference cell is The battery system of claim 7 , corresponding to a temperature measured at the top surface of the reference cell.

9. An output prediction method for predicting an output of a battery having a plurality of battery modules each including a plurality of battery cells, comprising: receiving a plurality of module temperatures, the module temperatures being temperatures of a plurality of the battery modules; determining a representative temperature corresponding to a temperature of the battery based on the plurality of module temperatures, a coolant temperature that is a temperature of coolant flowing between the plurality of battery modules, and an atmospheric temperature; predicting an output value of the battery based on the determined representative temperature and a state of charge of the battery determined according to a predetermined criterion.

10. The step of determining the representative temperature includes: determining whether the plurality of module temperatures fall within an average temperature range corresponding to a temperature range exceeding a first predetermined reference temperature and less than a second predetermined reference temperature; 10. The battery output prediction method of claim 9, further comprising: a first temperature determination step of determining a maximum value of the plurality of module temperatures as the representative temperature when the plurality of module temperatures fall within the average temperature range as a result of the determination regarding the plurality of module temperatures.

11. The step of determining the representative temperature includes: determining whether the atmospheric temperature is lower than the cooling water temperature when the module temperatures are not within the average temperature range as a result of the determination of the module temperatures; and determining a minimum value of the plurality of module temperatures as the representative temperature when the atmospheric temperature is lower than the cooling water temperature as a result of the determination of the atmospheric temperature. The method of claim 10, wherein the first temperature determination step is performed when the atmospheric temperature is equal to or higher than the coolant temperature as a result of the determination of the atmospheric temperature.

12. After the step of predicting the output value of the battery, determining whether the representative temperature belongs to an extreme temperature range corresponding to a temperature range below a minimum reference temperature that is a predetermined temperature lower than the first reference temperature and a temperature range exceeding a maximum reference temperature that is a predetermined temperature higher than the second reference temperature; correcting the predicted output value by reducing it according to a predetermined criterion when the representative temperature is within the extreme temperature range as a result of the determination of the representative temperature; 12. The method of claim 10, further comprising: determining the predicted output value as the output of the battery when the representative temperature does not fall within the extreme temperature range as a result of the determination regarding the representative temperature.

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