Battery system management device and method, for determining optimal number of batteries

Abstract

A battery system management device, according to one embodiment of the present invention, may comprise: at least one processor; and a memory for storing one or more instructions executed through the at least one processor. Here, the one or more instructions may include instructions for: defining an equivalent model for a battery system, comprising a plurality of batteries and at least one protection element and being formed into a predefined connection structure; by using the equivalent model, calculating a short-circuit current generated in the battery system when a short-circuit occurs at a specific position in the battery system; comparing the calculated short-circuit current with a limiting current of the protection element; and, on the basis of the comparison result, determining the number of batteries being provided in the battery system.

Description

Battery system management device and method for determining the optimal number of batteries

[0001] This application is based on and claims the benefit of priority from Korean Patent Application Nos. 10-2023-0084787 and 10-2023-0113262, filed with the Korean Intellectual Property Office on June 30, 2023 and August 29, 2023, respectively, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a battery system management device and method.

[0003] Secondary batteries are batteries that can be reused by charging even after discharge, and can be used as an energy source for small devices such as mobile phones, tablet PCs, and vacuum cleaners, and are also used as an energy source for medium and large devices such as automobiles and ESS (Energy Storage Systems) for smart grids.

[0004] Secondary batteries are applied to systems in the form of assemblies, such as battery modules, in which multiple battery cells are connected in series and / or parallel, or battery packs, in which battery modules are connected in series and / or parallel, depending on the system requirements. For medium- to large-sized devices, such as ESS for smart grids, high-capacity battery systems, in which multiple battery racks are connected in parallel, can be applied to meet the device's capacity requirements.

[0005] Meanwhile, the number of batteries included in such a battery system can be adjusted according to, for example, the size of the short-circuit current in the battery, and in this regard, appropriate battery system management technology is required according to the situation (see Korean Patent Publication No. 10-2010-0050514).

[0006] The present invention provides a battery system management device that determines the optimal number of batteries to be provided in a battery system.

[0007] The present invention also provides a battery system management method using such a battery system management device.

[0008] A battery system management device according to one embodiment of the present invention for achieving the above purpose may include at least one processor; and a memory storing at least one command executed through the at least one processor.

[0009] Here, the at least one command may include: a command defining an equivalent model for a battery system including a plurality of batteries and one or more protection elements and formed with a predefined connection structure; a command calculating a short-circuit current generated in the battery system by reflecting a time constant characteristic of a connection element according to the predefined connection structure when a short circuit occurs at a specific location in the battery system using the equivalent model; a command comparing the calculated short-circuit current with a limit current of the protection element; and a command determining the number of batteries provided in the battery system based on a comparison result.

[0010] The above protection element may be placed at one or more of the input / output terminals of the battery, the connection points of the batteries, and the connection points of the battery groups.

[0011] The command defining the equivalent model may include a command defining an equivalent model for the battery system based on a first equivalent model for the battery, a second equivalent model for the protection element, and a third equivalent model for a connection element electrically connecting the battery and an external device. Here, the third equivalent model may be defined as an RL equivalent circuit having a resistance value and inductance corresponding to the length of the connection element.

[0012] The command for calculating the short-circuit current may include a command for calculating the short-circuit current applied to each of the plurality of protection elements by reflecting the time constant characteristics of the connection elements according to the defined connection structure when a short-circuit occurs at one or more locations.

[0013] The location where the above-mentioned short circuit occurs may include one or more of a first location defined inside the battery, a second location defined between connection points of batteries, a third location defined between connection points of batteries and connection points of battery groups, and a fourth location defined between connection points of battery groups and a power conversion device.

[0014] The above comparing commands may include a command for checking, for each of the plurality of protection elements, whether the short-circuit current exceeds a limit current defined based on the short-circuit capacity of the protection element.

[0015] The command for determining the number of batteries may include a command for determining the maximum number of batteries such that the short-circuit current applied to each of the protection elements does not exceed the limit current of each of the protection elements.

[0016] The command for calculating the short-circuit current may include a command for calculating the short-circuit current applied to each of the protection elements by reflecting the time constant characteristics of the connection elements according to the predefined connection structure for each of the cases in which a short-circuit occurs at a plurality of locations. Here, the command for determining the number of batteries may include a command for determining the maximum number of batteries so that the short-circuit current applied to each of the protection elements does not exceed the limit current of each of the protection elements for all cases.

[0017] The command for determining the maximum number of batteries may include a command for redefining the equivalent model by changing the number of batteries included in the battery system based on the comparison result of the short-circuit current and the limit current; and a command for recalculating the short-circuit current based on the redefined equivalent model.

[0018]

[0019] According to an embodiment of the present invention for achieving the above-described other object, a method for managing a battery system by a battery system management device may include: defining an equivalent model for a battery system including a plurality of batteries and one or more protection elements and formed with a predefined connection structure; calculating a short-circuit current generated in the battery system by reflecting a time constant characteristic of a connection element according to the predefined connection structure when a short circuit occurs at a specific location in the battery system using the equivalent model; comparing the calculated short-circuit current with a limit current of the protection element; and determining the number of batteries provided in the battery system based on a comparison result.

[0020] The above protection element may be placed at one or more of the input / output terminals of the battery, the connection points of the batteries, and the connection points of the battery groups.

[0021] The step of defining the equivalent model may include a step of defining an equivalent model for the battery system based on a first equivalent model for the battery, a second equivalent model for the protection element, and a third equivalent model for a connecting element that electrically connects the battery and an external device. Here, the third equivalent model may be defined as an RL equivalent circuit having a resistance value and inductance corresponding to the length of the connecting element.

[0022] The step of calculating the short-circuit current may include a step of calculating the short-circuit current applied to each of the plurality of protection elements by reflecting the time constant characteristics of the connection elements according to the above-defined connection structure when a short-circuit occurs at one or more locations.

[0023] The location where the above-mentioned short circuit occurs may include one or more of a first location defined inside the battery, a second location defined between connection points of batteries, a third location defined between connection points of batteries and connection points of battery groups, and a fourth location defined between connection points of battery groups and a power conversion device.

[0024] The above comparing step may include a step of checking, for each of the plurality of protection elements, whether the short-circuit current exceeds a limit current defined based on the short-circuit capacity of the protection element.

[0025] The step of determining the number of batteries may include a step of determining the maximum number of batteries such that the short-circuit current applied to each of the protection elements does not exceed the limit current of each of the protection elements.

[0026] The step of calculating the short-circuit current may include a step of calculating the short-circuit current applied to each of the protection elements by reflecting the time constant of the connection element according to the predefined connection structure, for each of the cases in which a short-circuit occurs at a plurality of locations. Here, the step of determining the number of batteries may include a step of determining the maximum number of batteries so that the short-circuit current applied to each of the protection elements does not exceed the limit current of each of the protection elements, for all cases.

[0027] The step of determining the maximum number of batteries may include a step of redefining an equivalent model by changing the number of batteries included in the battery system based on a comparison result of a short-circuit current and a limit current; and a step of recalculating the short-circuit current based on the redefined equivalent model.

[0028] According to the above-described embodiment of the present invention, by determining the optimal number of batteries included in a battery system using an equivalent model for the battery system, the design cost of the battery system can be minimized and the energy density can be maximized, thereby enhancing product competitiveness.

[0029] Figure 1 is a block diagram of a typical battery system.

[0030] Figures 2(a) and 2(b) are graphs for explaining the short-circuit current generated in the battery system of Figure 1.

[0031] Figure 3 is a block diagram of a battery system to which the present invention can be applied.

[0032] Figure 4 is an operation flowchart of a battery system management method according to an embodiment of the present invention.

[0033] FIG. 5 is a block diagram illustrating an equivalent model of a battery system according to an embodiment of the present invention.

[0034] Figure 6 is an operational flowchart of a battery system management method according to another embodiment of the present invention.

[0035] FIG. 7 is a circuit diagram for explaining an equivalent model of a battery according to an embodiment of the invention.

[0036] Figures 8 and 9 are examples of battery systems to which the present invention can be applied.

[0037] Figure 10 is an operational flowchart of a battery system management method according to another embodiment of the present invention.

[0038] Figure 11 is a block diagram for explaining the simulation results for the first case.

[0039] Figure 12 is a block diagram for explaining the simulation results for the second case.

[0040] Figure 13 is a block diagram for explaining the simulation results for the third case.

[0041] Figure 14 is a block diagram for explaining the simulation results for the fourth case.

[0042] Figure 15 is a block diagram for explaining the simulation results for the fifth case.

[0043] Figures 16(a) and 16(b) are block diagrams for explaining the structure of a battery system derived according to the present invention.

[0044] Figure 17 is a block diagram of a battery system management device according to an embodiment of the present invention.

[0045] In some of the accompanying drawings, corresponding components are designated by the same reference numerals. Those skilled in the art will appreciate that the drawings illustrate elements simply and clearly and are not necessarily drawn to scale. For example, to facilitate understanding of various embodiments, the dimensions of some elements depicted in the drawings may be exaggerated relative to other elements. Furthermore, elements of known technology that are useful or essential in commercially feasible embodiments may often not be depicted so as not to obscure the spirit of various embodiments of the present invention.

[0046] 100: Battery Rack

[0047] 200: BCP

[0048] 300: PCS

[0049] 400: Battery System Management Device

[0050] The present invention is susceptible to various modifications and embodiments, and the embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to the embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Similar reference numerals have been used to designate similar components throughout the description of each drawing.

[0051] Terms such as "first," "second," "A," and "B" may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, the first component could be referred to as the "second component," and similarly, the second component could also be referred to as the "first component." The term "and / or" includes any combination of multiple related items listed or any one of multiple related items listed.

[0052] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0053] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0054] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0055]

[0056] Some terms used in this specification are defined as follows:

[0057] A battery cell is the smallest unit that stores electricity, and a battery module is a collection of multiple battery cells that are electrically connected.

[0058] A battery rack is a system with a minimum single structure that can be monitored and controlled through a BMS (Battery Management System) by electrically connecting module units set by a battery manufacturer, and can be configured to include multiple battery modules (or battery racks) and at least one BPU (Battery Protection Unit) or protection device.

[0059] A battery bank can refer to a large-scale battery rack system comprised of multiple battery racks connected in parallel. A battery bank-level BMS can monitor and control the rack BMS (RBMS) at the battery rack level.

[0060] A battery assembly is a collection of multiple electrically connected battery cells that function as a power source when applied to a specific system or device. Here, the battery assembly may refer to a battery module, battery pack, battery rack, or battery bank, but the scope of the present invention is not limited to these entities.

[0061] The number of batteries included in a battery system is determined based on the magnitude of the short-circuit current in the battery and the short-circuit capacity of the protection device included in the battery system. For example, if the short-circuit current capacity of the protection device is 100 kA and the short-circuit current of a single battery is 10 kA, the maximum number of batteries connected in parallel is determined to be 10.

[0062] However, this method of determining the number of batteries has the problem of unnecessarily limiting the total number of batteries included in the battery system. For example, the total short-circuit current of a battery system is affected by various factors, such as the connection structure between the batteries and the type and length of the cables connecting each component. However, if the number of batteries is determined simply based on the magnitude of the short-circuit current in the batteries and the short-circuit capacity of the protection devices included in the battery system, the total short-circuit current of the battery system is calculated assuming that each battery has the same short-circuit current, resulting in an overestimation of the actual total short-circuit current. Consequently, the maximum number of batteries included in the battery system is unnecessarily limited, which unnecessarily increases the design cost of the battery system and lowers the energy density, potentially weakening product competitiveness.

[0063] The present invention solves these problems and provides a battery management system capable of optimizing the connection of a battery by predicting the short-circuit current of a battery and a battery system.

[0064] The present invention and various embodiments thereof will be described in detail with reference to the drawings below.

[0065] FIG. 1 is a block diagram of a battery system (10) of the present invention according to one embodiment, and FIG. 2 is a graph for explaining a short-circuit current generated in the battery system (10) of FIG. 1.

[0066] Referring to FIG. 1, the battery system (10) may include a plurality of battery racks (100). Here, the plurality of battery racks (100) are connected in parallel to a Battery Control Panel (BCP) (200), and the BCP (200) may be electrically connected to, for example, a power conversion system (PCS) (300) described later in FIG. 3.

[0067] Inside each of the battery racks (100), a BPU (Battery Protection Unit) (110) is provided, and the BPU (110) may include one or more protection elements (110) (e.g., fuses and / or switching devices). In addition, the BCP (200) may include one or more protection elements (210) (e.g., fuses and / or switching devices).

[0068] For example, the number of battery racks (100) connected in parallel in a unit battery system (10) is determined based on the magnitude of the short-circuit current and the short-circuit capacity of the protection element. For example, if the short-circuit current capacity of the protection element (210) arranged inside the BCP (200) is 100 kA and the short-circuit current applied to each of the racks is 10 kA, the maximum number of battery racks (100) that can be configured in the battery system can be determined to be 10.

[0069] However, according to this method, there is a problem in that the total number of battery racks (100) provided in the battery system (10) is unnecessarily limited.

[0070] Fig. 2(A) shows the short-circuit current applied to each of a plurality of battery racks (100), in this embodiment, five battery racks connected in parallel, when a short-circuit occurs in the battery system, and Fig. 2(B) shows the total short-circuit current, which is the sum of the short-circuit currents of the plurality of battery racks (100).

[0071] As shown in the structure illustrated in FIG. 1, due to the connection structure of the battery system (10), the installation positions of each of the battery racks (100) within the battery system (10) may be different, and the lengths of the cables for connection to the BCP may be different for each rack. Accordingly, as illustrated in FIG. 2(A), when the battery is short-circuited, the short-circuit current applied to each of the battery racks (100) reaches the maximum current at different times due to the difference in the time constant. Due to this difference in the time constant for each battery rack (100), the maximum value of the total short-circuit current becomes smaller than the sum of the maximum short-circuit current values ​​of each of the battery racks (100), as illustrated in FIG. 2(B).

[0072] However, the method for calculating the number of batteries described above assumes that the short-circuit current of each battery rack (100) is the same, and thus the total short-circuit current of the battery system (10) is calculated, and thus the total short-circuit current is evaluated to be higher than the actual current. Accordingly, the number of battery racks (100) included in the battery system (10) is unnecessarily limited, which unnecessarily increases the design cost of the battery system (10), and further, the energy density is lowered, which weakens the competitiveness of the product.

[0073]

[0074] Figure 3 is a block diagram of a battery system (20) to which the present invention can be applied according to one embodiment.

[0075] A battery system (20) according to one embodiment may include a plurality of battery racks (100), one or more BCPs (200), and a power conversion device (300) (PCS; Power Conversion System). The plurality of battery racks (100) are configured to be connected in parallel to the BCPs (200), and the plurality of BCPs (200) may be connected in parallel to the power conversion devices (300). Inside each of the battery racks (100), a BPU (110) and a battery management system (BMS) (120) may be provided. Here, the BPU (110) may include one or more protection elements (e.g., a fuse and / or a switching device). The BMS (120) may be a rack battery management system (RBMS).

[0076] One or more protection elements (210) (e.g., fuses and / or switching devices) may be included inside the BCP (200). In addition, one or more protection elements (310) (e.g., fuses and / or switching devices) may be arranged on the connection path between the PCS (300) and the BCP (200). In addition, the battery rack (100), the BCP (200), and the PCS (300) may be electrically connected to each other through connection elements (130, 230). Here, the connection elements (130, 230) may be formed of a conductive metal, and may include, for example, one or more of a cable and a bus bar.

[0077] Meanwhile, according to one embodiment, a battery system management device (400) may be connected to at least one BCP (200) among a plurality of BCPs (200). Such a battery system management device (400) may be installed inside the BCP (200) or may be connected to the outside of the BCP (200) via a wire or wireless connection to manage the battery system.

[0078] Each of the protection elements (110, 210, 310) included in the battery system (20) may have a specific limit current value. Here, the limit current value may be defined as a value obtained by multiplying the short-circuit capacity of the protection element by a predefined adjustment constant (K). For example, the adjustment constant (K) may be defined as a specific value of approximately 0.8 or more and 1 or less. For example, if the short-circuit capacity of a specific protection element is 100 kA and the adjustment constant (K) is 0.95, the limit current of the protection element may be defined as 95 kA (100 kA * 0.95).

[0079] The structure of the battery system (20) illustrated in FIG. 3 is an example for the present invention, and the scope of the present invention is not limited to this structure. For example, a specific or entire battery rack (100) may be applied with an individual DC / DC converter rather than a BPU (110), and the battery system (20) may be applied with batteries in modules or packs rather than battery racks.

[0080] FIG. 4 is a flowchart illustrating an operation of a battery system management method according to an embodiment of the present invention. The battery system management method according to the present invention may be performed, for example, by a battery system management device (400). The battery system management device (400) is illustrated in FIG. 17.

[0081] The battery system management device (400) can define an equivalent model for the battery system (20) (S410).

[0082] According to one embodiment, a battery system may include a plurality of batteries and one or more protection elements, formed in a predetermined connection structure. The protection elements may be positioned, for example, at one or more of the input / output terminals of the batteries, connection points between the batteries, and connection points between battery groups. Meanwhile, the battery may refer to a battery cell or a battery assembly.

[0083] FIG. 5 is a block diagram for explaining an equivalent model of a battery system (30) according to an embodiment of the present invention.

[0084] The battery system management device (400) can define an equivalent model of a battery system (30) corresponding to the structure of an actual battery system (20).

[0085] For example, the battery system management device (400) may define an equivalent model of a battery system (30) including a total of N batteries and a power conversion device, as illustrated in FIG. 5. Here, M batteries connected in parallel may be defined as a first group, and the remaining batteries connected in parallel may be defined as a second group.

[0086] The location of the protection element can be defined to correspond to its location in an actual battery system. For example, the location of the protection element can be defined as the input / output terminal (A) of each battery, the parallel connection point (B) of the batteries, and the parallel connection point (C) of the battery groups.

[0087] Each of the protection elements included in the equivalent model can have a defined limit current. Here, the limit current can be defined as the product of the short-circuit capacity of the actual protection element and a predefined adjustment constant (K).

[0088] The battery system management device (400) can define an equivalent model for the entire battery system based on a first equivalent model for the battery, a second equivalent model for the protection element, and a third equivalent model for the connection element (130, 230) that electrically connects the battery and an external device. Here, the first equivalent model can be defined as an equivalent circuit including an internal resistance (Ric) and an internal inductance (Lic) according to the characteristics of the battery, the second equivalent model can be defined as an equivalent circuit including a resistance (Rarc), a capacitor (Carc), and a switch according to the characteristics of the protection element, and the third equivalent model can be defined as an equivalent circuit including a resistance (Rec) and an inductance (Lec) according to the length and characteristics of the connection element (130, 230).

[0089] Referring again to FIG. 4, the battery system management device (400) can calculate the short-circuit current generated in the battery system when a short-circuit occurs at a specific location within the battery system using the equivalent model defined in S410 (S420). For example, the battery system management device (400) can calculate the short-circuit current generated at a specific location within the battery system when a short-circuit occurs within the battery.

[0090] When a battery system includes multiple protection elements, the battery system management device (400) can calculate the short-circuit current applied to each of the multiple protection elements. For example, when a short-circuit occurs within the battery, the battery system management device (400) can calculate the short-circuit current applied to each of the protection elements included in the battery system.

[0091] A location where a short circuit occurs within a battery system can be predefined. Here, the location where a short circuit occurs can include one or more of a first location defined as inside a battery, a second location defined as between connection points between batteries, a third location defined as between connection points between batteries and connection points between battery groups, and a fourth location defined as between connection points between battery groups and a power conversion device. For example, in FIG. 5, the location where a short circuit occurs can be defined as one or more of the following: inside a battery (P1), between parallel connection points between batteries (P2), between parallel connection points between batteries and parallel connection points between battery groups (P3), and between parallel connection points between battery groups and a power conversion device (P4).

[0092] The battery system management device (400) can calculate the short-circuit current generated in the battery system when a short-circuit occurs at each of multiple locations within the battery system. For example, the battery system management device (400) can calculate the short-circuit current applied to each of the protection elements when a short-circuit occurs at P1, and can calculate the short-circuit current applied to each of the protection elements when a short-circuit occurs at P2. As another example, the battery system management device (400) can calculate the short-circuit current applied to each of the protection elements when a short-circuit occurs simultaneously at P1 and P2.

[0093] The battery system management device (400) can compare the short-circuit current calculated in S420 with the limit current of the protection element included in the battery system (S430).

[0094] In an embodiment, the battery system management device (400) may determine whether the short-circuit current of each protection element included in the battery system exceeds the limit current. For example, the battery system management device (400) may compare the short-circuit current applied to each protection element with the limit current of each protection element for all protection elements, and determine whether there is a protection element whose short-circuit current exceeds the limit current.

[0095] The battery system management device (400) may determine the number of batteries provided in the battery system based on the comparison result of S430 (S440). Here, the battery system management device (400) may determine the number of batteries so that the short-circuit current applied to each protection element does not exceed the limit current of each protection element. For example, if the short-circuit current applied to a specific protection element exceeds the limit current of each protection element, the battery system management device (400) may determine that the protection element cannot withstand the short-circuit current and sequentially reduce the number of batteries. Conversely, if the short-circuit current applied to the protection element is less than the limit current value of each protection element, the battery system management device (400) may determine that the protection element can withstand the short-circuit current and may maintain the status quo or attempt to sequentially increase the number of batteries.

[0096] In an embodiment, the battery system management device (400) may determine the maximum number of batteries that allow all protection elements of the battery system to withstand short-circuit current.

[0097] For example, the battery system management device (400) can perform a simulation (S410 to S430) for calculating a short-circuit current for a battery system composed of N batteries. If it is confirmed that all protection elements can withstand the short-circuit current (the short-circuit current is less than or equal to the limit current), the battery system management device (400) can perform a simulation (S410 to S430) for a battery system composed of N+1 batteries. Here, if it is confirmed that one or more protection elements cannot withstand the short-circuit current (the short-circuit current exceeds the limit current), the battery system management device (400) can determine the maximum number of batteries in the battery system as N.

[0098] In an embodiment, the battery system management device (400) may calculate a short-circuit current applied to each of the protection elements for each of the cases in which a short-circuit occurs at a plurality of locations, and determine a maximum number of batteries for all cases such that all the protection elements can withstand the short-circuit current.

[0099] For example, the battery system management device (400) may perform simulations (S410 to S430) for cases where a short circuit occurs in each of P1 to P4 for a battery system composed of N batteries. If it is confirmed that all protection elements can withstand the short circuit current for all cases (the short circuit current is less than or equal to the limit current), the battery system management device (400) may perform simulations (S410 to S430) for four cases for a battery system composed of N+1 batteries. Here, if it is confirmed that one or more protection elements cannot withstand the short circuit current (the short circuit current exceeds the limit current), the battery system management device (400) may determine the maximum number of batteries in the battery system to be N.

[0100]

[0101] Figure 6 is an operational flowchart of a battery system management method according to another embodiment of the present invention.

[0102] The battery system management device (400) can define an equivalent model for a battery system (30) including N batteries (S610).

[0103] Thereafter, the battery system management device (400) can calculate the short-circuit current applied to the protection element when a short-circuit occurs at a location within the battery system using the equivalent model defined in S610 (S620).

[0104] Here, the battery system management device (400) can calculate the short-circuit current applied to each of the plurality of protection elements for each case in which a short-circuit occurs at one or more locations. For example, the battery system management device (400) can calculate the short-circuit current applied to each of the plurality of protection elements for each of the cases in which a short-circuit occurs at P1 to P4.

[0105] The battery system management device (400) can compare the short-circuit current calculated in S620 with the limit current of the protection element (S630). Here, the battery system management device (400) can compare the short-circuit current and the limit current of the protection elements for all multiple cases.

[0106] For all multiple cases, if the short-circuit current of all protection elements is confirmed to be below the limit current (Y of S640), the battery system management device (400) can redefine the equivalent model by changing the number of batteries included in the battery system to N+1 (S610) and calculate the short-circuit current using the redefined equivalent model (S620).

[0107] Here, if one or more protection elements whose short-circuit current exceeds the limit current are detected (N of S640), the battery system management device (400) can determine the maximum number of batteries in the battery system as N (S650).

[0108]

[0109] FIG. 7 is a circuit diagram for explaining an equivalent model of a battery according to an embodiment of the invention.

[0110] The battery system management device (400) can define an equivalent model for the entire battery system based on a first equivalent model for the battery, a second equivalent model for the protection device, and a third equivalent model for the connection device (130, 230) that electrically connects the battery and an external device. Here, the battery system management device (400) can calculate a short-circuit current value using the equivalent model.

[0111] The first equivalent model for a battery can be defined as an equivalent circuit that reflects the characteristics of the battery.

[0112] For example, the first equivalent model may include an equivalent circuit of a battery and an equivalent circuit inside the battery. Here, the equivalent circuit of the battery may be defined as a circuit in which an open circuit voltage (OCV), a first resistor (Ri), a second resistor (Rd) connected in parallel with each other, and a capacitor (Cd) are connected in series. In addition, the equivalent circuit inside the battery may be defined as an RL series circuit that efficiently represents the characteristics of a short-circuit state in a DC circuit, and may be defined as a circuit in which an internal resistance (Ric) and an internal inductor (Lic) are connected in series.

[0113] A second equivalent model for the protection element can be defined as a circuit including a resistor (Rarc), a capacitor (Carc), and a switch.

[0114] Meanwhile, in a battery system, voltage and current characteristics can change based on the occurrence of a short circuit. Accordingly, a protective element (e.g., a fuse) can change from a first state (Melting) to a second state (Clearing) based on the occurrence of a short circuit.

[0115] Here, the first state may be a state in which the conductor begins to melt due to heat generated inside the fuse before an arc occurs, and the second state may be a state in which the conductor melts and current flows into the air, causing an arc to occur.

[0116] The second equivalent model according to the embodiment of the present invention can be implemented as a circuit including a resistor (Rarc), a capacitor (Carc), and a switch, as shown in FIG. 7, in order to implement the melting characteristics of such a protection element.

[0117] A third equivalent model for the connecting element (130, 230) can be defined as an RL circuit in which a resistor (Rec) and an inductor (Lec) are connected in series. Here, the resistor (Rec) and the inductor (Lec) can be defined as resistance values ​​and inductances depending on the length and characteristics of the connecting element (130, 230) (e.g., a cable or a busbar).

[0118] Since the equivalent model according to an embodiment of the present invention is defined by reflecting the characteristics of the connection elements (130, 230) according to the connection structure of the battery system, the battery system management device (400) can calculate a short-circuit current reflecting the difference in time constants for each connection element (130, 230), and thus more accurately determine the optimal number of batteries that can be applied to the battery system.

[0119]

[0120] FIGS. 8 and 9 are examples of battery systems to which the present invention can be applied according to one embodiment. The battery system illustrated in FIG. 8 is configured to include a plurality of battery racks (100) as B-Links, and the battery system illustrated in FIG. 9 can be configured to include a PCS (300) including a plurality of AC / DC inverters and a plurality of DC-Links.

[0121] In Fig. 9, each of the AC / DC inverters may be electrically connected to a DC-Link. Here, each DC-Link may include an E-Link and a plurality of B-Links. The E-Link may have one or more protection devices (e.g., a fuse or a switching device) installed therein. The plurality of B-Links may be connected in parallel to the E-Link. Here, each B-Link may include a plurality of battery racks (100) connected in parallel.

[0122] In Fig. 8, the B-Link may include a BCP (200) and a plurality of battery racks (100). Here, the plurality of battery racks (100) are connected in parallel to the BCP (200), and the BCP (200) may be electrically connected to the E-Link. Each of the plurality of battery racks (100) may be equipped with a BPU therein.

[0123] BCP (200) and BPU (110) may be provided with one or more protection elements (e.g., fuses and / or switching devices) internally.

[0124] The battery system management device (400) can define an equivalent model for the battery system illustrated in FIGS. 8 and 9, and use the defined equivalent model to determine the maximum number of battery racks (100) that can be included in the battery system.

[0125] Here, the battery system management device (400) calculates the short-circuit current applied to each of the protection elements by reflecting the time constant characteristics of the connection elements (130, 230) according to the predefined connection structure for each of the cases where a short circuit occurs at a plurality of locations, and determines the maximum number of batteries that enable all the protection elements to withstand the short-circuit current for all cases.

[0126] In the battery system illustrated in FIGS. 8 and 9, the location where a short-circuit current occurs may include one or more locations among the inside of the battery rack (P1), between the battery rack (100) and the BCP (200) (P2), between the BCP and the E-Link (P3), and between the E-Link and the PCS (300) (P4), similar to the case of FIG. 5.

[0127]

[0128] Figure 10 is a flowchart illustrating an operational flowchart of a battery system management method according to another embodiment of the present invention. Figures 11 to 15 are block diagrams illustrating simulation results for cases 1 to 5. Below, with reference to Figures 10 to 15, a method for determining the optimal number of batteries in the battery system illustrated in Figures 8 and 9 will be described.

[0129] Referring to FIG. 10, the battery system management device (400) sequentially performs simulations for calculating short-circuit current for each case where a short circuit occurs at multiple locations, and sequentially checks the simulation results to determine the maximum number of batteries configured in the battery system. For example, the battery system management device (400) may sequentially perform simulations from the highest to the lowest structural location of the battery system. For example, the simulations for calculating short-circuit current may be performed in the order of P4, P3, P2, and P1.

[0130] Referring to FIG. 10, the battery system management device (400) can perform a simulation for calculating short-circuit current for a case (first case) in which a short-circuit occurs at P4 using an equivalent model of a battery system including N batteries (S1010).

[0131] According to one embodiment, when a short circuit occurs at P4, which is the structurally highest position of the battery system, as illustrated in FIG. 11, a large short circuit current applied from DC-Links #1 to #3 flows toward the AC / DC converter connected to DC-Link #1. At this time, each of the protection elements configured in the battery system must be able to withstand the generated short circuit current. For example, as illustrated in FIG. 5, each of the protection elements located at A, B, and C must be able to withstand the large short circuit current applied from DC-Links #1 to #3 at each position.

[0132] The battery system management device (400) can compare the short-circuit current and the limit current of each protection element produced as a result of the simulation.

[0133] As a result of the comparison, if it is confirmed that the short-circuit current of all protection elements is below the limit current (Y of S1020), the battery system management device (400) can redefine the equivalent model by changing the number of battery racks (100) included in the battery system (for example, increasing by 1) and perform a simulation using the redefined equivalent model. For example, in this case, the battery system management device (400) determines that all protection elements can withstand the short-circuit current increased by the short-circuit at each location, and redefines the equivalent model by increasing the number of battery racks (100) and performs a simulation.

[0134] If one or more protection elements whose short-circuit current exceeds the limit current are detected (N of S1020), the battery system management device (400) can determine the maximum number of battery racks (100) applicable to the battery system as N.

[0135] Next, the battery system management device (400) can proceed with the next step of simulation for calculating short-circuit current for the case (second case) in which a short-circuit occurs at P3 (S1030).

[0136] When a short circuit occurs at P3, as illustrated in Fig. 12, a large short circuit current applied from DC-Links #2 and #3 and the B-Links of DC-Link #1 flows to the E-Link side of DC-Link #1. At this time, each of the protection elements configured in the battery system must be able to withstand the generated short circuit current.

[0137] The battery system management device (400) can compare the short-circuit current and the limit current of each protection element produced as a result of the simulation.

[0138] If one or more protection elements whose short-circuit current exceeds the limit current are detected (N of S1040), the battery management device (400) determines that one or more protection elements cannot withstand the short-circuit current that has occurred, and redefines the equivalent model by changing the number of battery racks (100) included in the battery system (for example, reducing by 1), and performs a simulation using the redefinition of the equivalent model.

[0139] Meanwhile, if the short-circuit current of all protection elements is confirmed to be below the limit current (Y of S1040), the battery system management device (400) can perform a simulation to calculate the short-circuit current for the case (third case) in which a short-circuit occurs in P2 (S1050).

[0140] When a short circuit occurs at P2, as illustrated in Fig. 13, a large short circuit current applied from the battery racks (100) of DC-Link #2 and #3 and B-Link #2 of DC-Link #1 flows to the BCP side of B-Link #2. At this time, each of the protection elements configured in the battery system must be able to withstand the short circuit current generated at each location.

[0141] The battery system management device (400) can compare the short-circuit current and the limit current of each protection element produced as a result of the simulation.

[0142] If one or more protection elements whose short-circuit current exceeds the limit current are detected (N of S1060), the battery system management device (400) determines that one or more protection elements cannot withstand the short-circuit current that has occurred, and redefines the equivalent model by changing the number of battery racks (100) included in the battery system (for example, reducing by 1), and performs a simulation using the redefinition of the equivalent model.

[0143] If the short-circuit current of all protection elements is confirmed to be below the limit current (Y of S1060), the battery system management device (400) can proceed with a simulation for calculating the short-circuit current for the case (fourth case) in which a short-circuit occurs in P1 as the next step (S1070).

[0144] When a short circuit occurs at P1, as illustrated in Fig. 14, a large short circuit current applied from DC-Links #2 and #3 and other battery racks (100) of B-Link #2 of DC-Link #1 flows to the BPU (110) side of the rack where the short circuit current occurred. At this time, each of the protection elements configured in the battery system must be able to withstand the short circuit current generated at each location.

[0145] The battery system management device (400) can compare the short-circuit current and the limit current of each protection element produced as a result of the simulation.

[0146] If one or more protection elements whose short-circuit current exceeds the limit current are detected (N of S1080), the battery system management device (400) can redefine the equivalent model by changing the number of battery racks (100) included in the battery system (for example, reducing by 1), and perform a simulation using the redefined equivalent model.

[0147] When the short-circuit current of all protection elements is confirmed to be below the limit current (Y of S1080), the battery system management device (400) can finally determine the number of batteries applied to the current equivalent model as the optimal number of batteries of the battery system (S1090).

[0148] Meanwhile, the battery system management device (400) can additionally perform a simulation for cases where a short circuit occurs simultaneously at multiple locations or at regular time intervals, and calculate the optimal number of batteries based on the simulation results.

[0149] For example, the battery system management device (400) can additionally perform a simulation for calculating short-circuit current for a case (fifth case) in which short-circuits occur simultaneously at P3 and P3', as illustrated in FIG. 15.

[0150] When short circuits occur simultaneously at P3 and P3', a large short circuit current flows through the E-Link of DC-Link #1 and the E-Link of DC-Link #3. At this time, each of the protection elements configured in the battery system must be able to withstand the short circuit current generated at each location. The battery system management device (400) performs a simulation for the fifth case in a similar manner to that described above, and can adjust the number of batteries by checking whether the short circuit current of all protection elements is below the limit current.

[0151]

[0152] Figure 16 is a block diagram illustrating the structure of a battery system derived according to the present invention.

[0153] Fig. 16(A) shows a battery system with an asymmetric parallel connection structure, and Fig. 16(B) shows a battery system with a symmetric parallel structure.

[0154] As for FIGS. 16(A) and 16(B), the maximum number of battery racks was calculated using the present invention, and it was confirmed that the asymmetric parallel connection structure (A) can include more battery racks (100) than the symmetric parallel connection structure (B).

[0155] In terms of the connection structure of the battery system, the length of the connection elements (130, 230) included in the symmetrical parallel connection structure (B) is shorter than that of the asymmetrical parallel connection structure (A), so that the inductance and resistance are relatively small. Accordingly, the symmetrical parallel connection structure (B) has a relatively small time constant, so that the total short-circuit current is relatively high. Conversely, the asymmetrical parallel connection structure (A) has a relatively low total short-circuit current, so that it can include more battery racks (100) than the symmetrical parallel connection structure (B).

[0156]

[0157] Figure 17 is a block diagram of a battery system management device (400) according to an embodiment of the present invention.

[0158] The battery system management device (400) may include at least one processor (410), a memory (420) that stores at least one command executed by the processor, and a transmission / reception device (430) that is connected to a network and performs communication. In addition, the battery system management device (400) may further include an input interface device (440), an output interface device (450), and a separate storage device (460). In addition, each component included in the battery system management device (400) may be connected by a bus (470) and communicate with each other.

[0159] The processor (410) may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. The memory (or storage device) may be comprised of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory may be comprised of at least one of a read-only memory (ROM) and a random access memory (RAM).

[0160] Meanwhile, at least one command executed through the processor may include: a command defining an equivalent model for a battery system including a plurality of batteries and one or more protection elements and formed with a predefined connection structure; a command calculating a short-circuit current generated in the battery system by reflecting a time constant characteristic of a connection element according to the predefined connection structure when a short circuit occurs at a specific location in the battery system using the equivalent model; a command comparing the calculated short-circuit current with a limit current of the protection element; and a command determining the number of batteries provided in the battery system based on a comparison result.

[0161] The above protection element may be placed at one or more of the input / output terminals of the battery, the connection points of the batteries, and the connection points of the battery groups.

[0162] The command defining the equivalent model may include a command defining an equivalent model for the battery system based on a first equivalent model for the battery, a second equivalent model for the protection element, and a third equivalent model for a connection element electrically connecting the battery and an external device. Here, the third equivalent model may be defined as an RL equivalent circuit having a resistance value and inductance corresponding to the length of the connection element.

[0163] The command for calculating the short-circuit current may include a command for calculating the short-circuit current applied to each of the plurality of protection elements by reflecting the time constant characteristics of the connection elements according to the defined connection structure when a short-circuit occurs at one or more locations.

[0164] The location where the above-mentioned short circuit occurs may include one or more of a first location defined inside the battery, a second location defined between connection points of batteries, a third location defined between connection points of batteries and connection points of battery groups, and a fourth location defined between connection points of battery groups and a power conversion device.

[0165] The command for comparing the short-circuit current calculated above with the limit current of the protection element may include a command for checking, for each of the plurality of protection elements, whether the short-circuit current exceeds the limit current defined based on the short-circuit capacity of the protection element.

[0166] The command for determining the number of batteries may include a command for determining the maximum number of batteries such that the short-circuit current applied to each of the protection elements does not exceed the limit current of each of the protection elements.

[0167] The command for calculating the short-circuit current may include a command for calculating the short-circuit current applied to each of the protection elements by reflecting the time constant characteristics of the connection elements according to the predefined connection structure for each of the cases in which a short-circuit occurs at a plurality of locations. Here, the command for determining the number of batteries may include a command for determining the maximum number of batteries so that the short-circuit current applied to each of the protection elements does not exceed the limit current of each of the protection elements for all cases.

[0168] The command for determining the maximum number of batteries may include a command for redefining the equivalent model by changing the number of batteries included in the battery system based on the comparison result of the short-circuit current and the limit current; and a command for recalculating the short-circuit current based on the redefined equivalent model.

[0169]

[0170] Meanwhile, the operation of the method according to an embodiment of the present invention can be implemented as a computer-readable program or code on a computer-readable recording medium. A computer-readable recording medium includes any type of recording device that stores data readable by a computer system. Furthermore, a computer-readable recording medium can be distributed across network-connected computer systems, allowing the computer-readable program or code to be stored and executed in a distributed manner.

[0171] While some aspects of the present invention have been described in the context of a device, they may also represent a description of a corresponding method, wherein a block or device corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method may also be described as a corresponding block or item or a feature of a corresponding device. Some or all of the method steps may be performed by (or using) a hardware device, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most significant method steps may be performed by such a device.

[0172] Although the present invention has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. At least one processor capable of communicating with the battery system; and A memory connected to at least one processor and storing at least one instruction executed through the processor; At least one of the above commands, A command defining an equivalent model for a battery system comprising a plurality of batteries and one or more protection elements and formed with a predefined connection structure; Using the above equivalent model, a command for calculating a short-circuit current generated in the battery system by reflecting the time constant characteristics of a connection element according to the above-defined connection structure when a short-circuit occurs at a location within the battery system; A command to compare the above-described short-circuit current with the limit current of the protection device; and A battery system management device, comprising a command for determining the number of batteries provided in the battery system based on the comparison result.

2. In claim 1, The above protection device is, A battery system management device disposed at one or more of the input / output terminals of a battery, connection points of batteries, and connection points of battery groups.

3. In claim 1, The command defining the above equivalent model is: A battery system management device comprising a command for defining an equivalent model for the battery system based on a first equivalent model for the battery; a second equivalent model for the protection device; and a third equivalent model for a connection device electrically connecting the battery and an external device.

4. In claim 3, The third equivalent model above is, A battery system management device defined by an RL equivalent circuit having a resistance value and inductance corresponding to the length of the above connecting element.

5. In claim 1, The command to calculate the above short circuit current is: A battery system management device, comprising a command for calculating a short-circuit current applied to each of the plurality of protection elements by reflecting the time constant characteristics of the connection elements according to the above-defined connection structure when a short circuit occurs at one or more locations.

6. In claim 5, The location where the above paragraph occurs is, A battery system management device comprising at least one of a first location defined within a battery, a second location defined between connection points of batteries, a third location defined between connection points of batteries and connection points of battery groups, and a fourth location defined between connection points of battery groups and a power conversion device.

7. In claim 5, The above comparing commands are: A battery system management device, comprising a command for determining, for each of a plurality of protection elements, whether a short-circuit current exceeds a limit current defined based on the short-circuit capacity of the protection element.

8. In claim 1, The command to determine the number of batteries is: A battery system management device, comprising a command for determining the maximum number of batteries so that the short-circuit current applied to each of the protection elements does not exceed the limit current of each of the protection elements.

9. In claim 8, The command to calculate the above short circuit current is: For each of the cases where a short circuit occurs at multiple locations, a command is included to calculate a short circuit current applied to each of the protection elements by reflecting the time constant characteristics of the connection elements according to the above-defined connection structure. The command to determine the number of batteries is: A battery system management device, comprising a command for determining the maximum number of batteries such that, for all cases, the short-circuit current applied to each of the protection elements does not exceed the limit current of each of the protection elements.

10. In claim 9, The command to determine the maximum number of batteries is: A command to redefine the equivalent model by changing the number of batteries included in the battery system based on the comparison results of the short-circuit current and the limit current; and A battery system management device, comprising a command to recalculate short-circuit current based on a redefined equivalent model.

11. A method for managing a battery system by a battery system management device, A step of defining an equivalent model for a battery system comprising a plurality of batteries and one or more protection elements and formed with a predefined connection structure; A step of calculating a short-circuit current generated in the battery system by reflecting the time constant characteristics of a connection element according to the defined connection structure when a short-circuit occurs at a specific location within the battery system using the equivalent model; A step of comparing the calculated short-circuit current with the limit current of the protection device; and A battery system management method, comprising a step of determining the number of batteries provided in the battery system based on the comparison result.

12. In claim 11, The above protection device is, A battery system management method, wherein the battery is positioned at one or more of the input / output terminals of the battery, the connection points of the batteries, and the connection points of the battery groups.

13. In claim 11, The steps for defining the above equivalent model are: A battery system management method, comprising the step of defining an equivalent model for the battery system based on a first equivalent model for the battery; a second equivalent model for the protection device; and a third equivalent model for a connection device electrically connecting the battery and an external device.

14. In claim 13, The third equivalent model above is, A battery system management method defined by an RL equivalent circuit having a resistance value and inductance corresponding to the length of the above connecting element.

15. In claim 11, The step of calculating the above short-circuit current is: A battery system management method, comprising a step of calculating a short-circuit current applied to each of a plurality of protection elements by reflecting the time constant characteristics of the connection elements according to the above-defined connection structure when a short circuit occurs at one or more locations.

16. In claim 15, The location where the above paragraph occurs is, A method for managing a battery system, comprising at least one of a first location defined within a battery, a second location defined between connection points of batteries, a third location defined between connection points of batteries and connection points of battery groups, and a fourth location defined between connection points of battery groups and a power conversion device.

17. In claim 15, The above comparing steps are: A battery system management method, comprising the step of checking, for each of a plurality of protection elements, whether a short-circuit current exceeds a limit current defined based on a short-circuit capacity of the protection element.

18. In claim 11, The step of determining the number of batteries is: A battery system management method, comprising the step of determining the maximum number of batteries so that the short-circuit current applied to each of the protection elements does not exceed the limit current of each of the protection elements.

19. In claim 18, The step of calculating the above short-circuit current is: For each of the cases where a short circuit occurs at multiple locations, a step of calculating a short circuit current applied to each of the protection elements is included by reflecting the time constant characteristics of the connection elements according to the above-defined connection structure. The step of determining the number of batteries is: A battery system management method, comprising the step of determining the maximum number of batteries such that, for all cases, the short-circuit current applied to each of the protection elements does not exceed the limit current of each of the protection elements.

20. In claim 19, The step of determining the maximum number of batteries is: A step of redefining the equivalent model by changing the number of batteries included in the battery system based on the comparison results of the short-circuit current and the limit current; and A battery system management method, comprising a step of recalculating short-circuit current based on a redefined equivalent model.

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