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

Abstract

A battery system management device according to an embodiment of the present invention may include at least one processor and a memory that stores at least one instruction executed by the at least one processor. Here, the at least one instruction may include an instruction to define an equivalent model for a battery system including a plurality of batteries and one or more protection elements formed in a predetermined connection structure, an instruction to calculate, using the equivalent model, a short-circuit current generated in the battery system when a short circuit occurs at a specific position within the battery system, an instruction to compare the calculated short-circuit current with a limit current of the protection element, and an instruction to determine the number of batteries to be provided in the battery system based on the comparison result.

Description

[Technical Field]

[0001] This application is based on and claims 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 contents of which are incorporated herein by reference in their entireties.

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

[0003] Secondary batteries are batteries that can be reused by recharging after discharge and can be used as an energy source for small devices such as mobile phones, tablet PCs, and vacuum cleaners, as well as for medium- to large-sized devices such as automobiles and smart grid energy storage systems (ESS).

[0004] Secondary batteries are applied to systems in the form of assemblies such as battery modules in which a number of 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 requirements of the system. In the case of medium- to large-sized devices such as ESS for smart grids, a high-capacity battery system in which a number of battery racks are connected in parallel may be applied to meet the required capacity of the device.

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

[0006] [Patent Document 1] Korean Patent Publication No. 10-2010-0050514 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention provides a battery system management device that determines the optimum number of batteries to be included in a battery system.

[0008] The present invention also provides a battery system management method using such a battery system management device. [Means for solving the problem]

[0009] To achieve the above object, a battery system management device according to one embodiment of the present invention may include at least one processor and a memory that stores at least one instruction executed by the at least one processor.

[0010] Here, the at least one instruction may include an instruction to define an equivalent model for a battery system formed in a predetermined connection structure including a plurality of batteries and one or more protection elements; an instruction to calculate, using the equivalent model, a short-circuit current generated in the battery system when a short circuit occurs at a specific position within the battery system, reflecting the time constant characteristics of the connection elements due to the predetermined connection structure; an instruction to compare the calculated short-circuit current with the limit current of the protection element; and an instruction to determine the number of batteries to be provided in the battery system based on the comparison result.

[0011] The protection element may be disposed at one or more of the input / output side of the battery, the connection point of the battery, and the connection point of the battery group.

[0012] The instructions for defining the equivalent model may include instructions 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 element, and a third equivalent model for a connection element that electrically connects the battery and the external device, where the third equivalent model may be defined as an RL equivalent circuit having a resistance and inductance corresponding to the length of the connection element.

[0013] The command to calculate the short-circuit current may include a command to calculate the short-circuit current applied to each of the plurality of protection elements when a short circuit occurs at one or more locations, reflecting the time constant characteristics of the connection elements due to a predetermined connection structure.

[0014] The location where the short circuit occurs can include one or more of a first location defined as inside the battery, a second location defined as between the battery and battery connection points, a third location defined as between the battery connection points and the battery group connection points, and a fourth location defined as between the battery group connection points and the power conversion device.

[0015] The instruction to compare may include an instruction to determine, 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.

[0016] The instructions for determining the number of batteries may include instructions for determining the maximum number of batteries that will prevent the short circuit current applied to each of the protection elements from exceeding the limit current of each of the protection elements.

[0017] The instruction to calculate the short-circuit current may include an instruction to calculate the short-circuit current applied to each of the protection elements, for each of the cases where a short circuit occurs at a plurality of positions, by reflecting the time constant characteristics of the connection elements according to a predetermined connection structure. Here, the instruction to determine the number of batteries may include an instruction to determine the maximum number of batteries that will prevent the short-circuit current applied to each of the protection elements from exceeding the limit current of each of the protection elements, for all cases.

[0018] The instruction to determine the maximum number of batteries may include an instruction to change the number of batteries included in the battery system and redefine the equivalent model depending on the result of comparing the short-circuit current with the limit current, and an instruction to recalculate the short-circuit current based on the redefined equivalent model.

[0019] To achieve another object, a battery system management method using a battery system management device according to one embodiment of the present invention includes the steps of: defining an equivalent model for a battery system formed in a predetermined connection structure including a plurality of batteries and one or more protection elements; calculating, using the equivalent model, a short-circuit current generated in the battery system when a short circuit occurs at a specific position within the battery system, reflecting the time constant characteristics of the connection elements due to the predetermined connection structure; comparing the calculated short-circuit current with the limit current of the protection element; and determining the number of batteries to be provided in the battery system based on the comparison result.

[0020] The protection element may be disposed at one or more of the input / output side of the battery, the connection point of the battery, and the connection point of the battery group.

[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 connection element that electrically connects the battery and the external device, where the third equivalent model may be defined as an RL equivalent circuit having a resistance and inductance corresponding to the length of the connection 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 when a short circuit occurs at one or more locations, reflecting the time constant characteristics of the connection elements due to the above-mentioned predetermined connection structure.

[0023] The location where the short circuit occurs can include one or more of a first location defined as inside the battery, a second location defined as between the battery and battery connection points, a third location defined as between the battery connection points and the battery group connection points, and a fourth location defined as between the battery group connection points and the power conversion device.

[0024] The comparing step may include the 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 the step of determining the maximum number of batteries that prevents the short-circuit current applied to each of the protection elements from exceeding the limit current of each of the protection elements.

[0026] The step of calculating the short-circuit current may include a step of calculating, for each case where a short circuit occurs at a plurality of positions, the short-circuit current applied to each of the protection elements, reflecting the time constant of the connection elements due to the predetermined connection structure. Here, the step of determining the number of batteries may include a step of determining, for all cases, the maximum number of batteries that prevents the short-circuit current applied to each of the protection elements from exceeding the limit current of each of the protection elements.

[0027] The step of determining the maximum number of batteries may include a step of changing the number of batteries included in the battery system and redefining the equivalent model depending on the result of comparing the short-circuit current with the limit current, and a step of recalculating the short-circuit current based on the redefined equivalent model. [Effects of the Invention]

[0028] According to the above-described embodiment of the present invention, by determining the optimal number of batteries to be included in a battery system using an equivalent model for the battery system, it is possible to minimize the design cost of the battery system, maximize the energy density, and strengthen product competitiveness. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a block diagram of a typical battery system. [Figure 2] 2 is a graph for explaining a short-circuit current that occurs in the battery system of FIG. 1. [Figure 3] 1 is a block diagram of a battery system to which the present invention may be applied. [Figure 4] FIG. 2 is an operational flow diagram of a battery system management method according to an embodiment of the present invention. [Figure 5] FIG. 2 is a block diagram for explaining an equivalent model of a battery system according to an embodiment of the present invention. [Figure 6] FIG. 10 is an operational flow diagram of a battery system management method according to another embodiment of the present invention. [Figure 7] FIG. 2 is a circuit diagram for explaining an equivalent model of a battery according to an embodiment of the present invention. [Figure 8] 1 is an example of a battery system to which the present invention may be applied. [Figure 9] 1 is an example of a battery system to which the present invention may be applied. [Figure 10] FIG. 10 is an operational flow diagram of a battery system management method according to yet another embodiment of the present invention. [Figure 11] FIG. 10 is a block diagram for explaining a simulation result for the first case. [Figure 12] FIG. 10 is a block diagram for explaining a simulation result for the second case. [Figure 13] FIG. 10 is a block diagram for explaining a simulation result for the third case. [Figure 14] FIG. 10 is a block diagram for explaining a simulation result for a fourth case. [Figure 15] FIG. 10 is a block diagram for explaining a simulation result for the fifth case. [Figure 16] FIG. 1 is a block diagram illustrating the structure of a battery system derived from the present invention. [Figure 17]1 is a block diagram of a battery system management device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] 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 the various embodiments, the dimensions of some elements shown in the drawings may be exaggerated relative to other elements. Furthermore, elements of the known art that are useful or essential in commercially viable embodiments may not often be depicted in order to avoid obscuring the spirit of the various embodiments of the present invention.

[0031] Since the present invention can be modified in various ways and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, it is understood that this is not intended to limit the present invention to the embodiments, but rather to include all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. Similar reference numerals are used to refer to similar components throughout the drawings.

[0032] Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by these terms. These terms are used only to distinguish one component from another. For example, a first component may be designated as a second component, and similarly, a second component may be designated as a first component, without departing from the scope of the present invention. The term "and / or" includes a combination of multiple associated listed items or any one of multiple associated listed items.

[0033] When a component is referred to as being "coupled" or "connected" to another component, it is understood that the component may be directly coupled or connected to the other component, but that there may be other components in between. Conversely, when a component is referred to as being "directly coupled" or "directly connected" to another component, it is understood that there are no other components in between.

[0034] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and are understood not to preclude the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0035] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as having an ideal or overly formal meaning unless expressly defined in this application.

[0036] Some terms used in this specification are defined as follows:

[0037] A battery cell is the smallest unit that serves to store power, and a battery module refers to an assembly of a plurality of battery cells that are electrically connected together.

[0038] A battery rack refers to a system with the smallest single structure that electrically connects module units set by a battery manufacturer and can be monitored and controlled through a BMS (Battery Management System), and may be composed of multiple battery modules (or battery racks) and at least one BPU (Battery Protection Unit) or protection device.

[0039] A battery bank can refer to a large-scale battery rack system consisting of multiple battery racks connected in parallel. The battery bank BMS can monitor and control the battery rack BMS (RBMS).

[0040] A battery assembly refers to an assembly including a plurality of electrically connected battery cells that is applied to a specific system or device and functions as a power supply source. Here, the battery assembly may refer to a battery module, a battery pack, a battery rack, a battery bank, or the like, but the scope of the present invention is not limited to these.

[0041] The number of batteries included in a battery system is determined based on the magnitude of the short-circuit current of the batteries and the short-circuit capacity of the protective elements included in the battery system. For example, if the short-circuit current capacity of the protective elements is 100 kA and the short-circuit current of the unit battery is 10 kA, the maximum number of batteries connected in parallel is determined to be 10.

[0042] 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 solely based on the magnitude of the short-circuit current of the batteries and the short-circuit capacity of the protective devices included in the battery system, the total short-circuit current of the battery system is calculated assuming that the short-circuit current of each battery is the same, resulting in an overestimated total short-circuit current. This unnecessarily limits the maximum number of batteries included in the battery system, which can unnecessarily increase the design cost of the battery system and reduce the energy density, thereby reducing product competitiveness.

[0043] The present invention solves these problems and provides a battery management system that can predict short-circuit currents in batteries and battery systems and optimize battery connections.

[0044] The invention and various embodiments thereof will now be described in detail with reference to the drawings.

[0045] FIG. 1 is a block diagram of a battery system 10 according to one embodiment of the present invention, and FIG. 2 is a graph illustrating a short-circuit current generated in the battery system 10 of FIG.

[0046] 1, a 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, which may be electrically connected to a Power Conversion System (PCS) 300, which will be described later with reference to FIG.

[0047] Each battery rack 100 includes a BPU (Battery Protection Unit) 110, which may include one or more protection elements 110 (e.g., fuses and / or switching devices). Also, the BCP 200 may include one or more protection elements 210 (e.g., fuses and / or switching devices).

[0048] As an example, the number of battery racks 100 connected in parallel in the 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 rack is 10 kA, the maximum number of battery racks 100 that may be configured in the battery system may be determined to be 10.

[0049] However, this method has the problem that the total number of battery racks 100 that can be provided in the battery system 10 is unnecessarily limited.

[0050] Figure 2(A) shows the short-circuit current applied to each of multiple battery racks 100, in this embodiment five battery racks connected in parallel, when a short circuit occurs in the battery system, and Figure 2(B) shows the total short-circuit current obtained by adding up the short-circuit currents of the multiple battery racks 100.

[0051] As can be seen from the structure shown in Figure 1, depending on the connection structure of the battery system 10, the installation positions of the battery racks 100 within the battery system 10 may differ, and the lengths of the cables for connecting to the BCP for each rack may differ. As a result, as shown in Figure 2(A), the short-circuit current applied to each battery rack 100 during a battery short circuit will reach its maximum current value at different times due to differences in the time constants. Due to these differences in the time constants for each battery rack 100, the maximum value of the total short-circuit current will be smaller than the sum of the maximum short-circuit currents of each battery rack 100, as shown in Figure 2(B).

[0052] However, the above-described battery number calculation method calculates the total short-circuit current of the battery system 10 under the assumption that the short-circuit current of each battery rack 100 is the same, which may result in the total short-circuit current being overestimated. This unnecessarily limits the number of battery racks 100 included in the battery system 10, unnecessarily increasing the design cost of the battery system 10 and lowering the energy density, reducing product competitiveness.

[0053] FIG. 3 is a block diagram of a battery system 20 to which the present invention may be applied according to one embodiment.

[0054] 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 system (PCS) 300. The plurality of battery racks 100 may be 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 systems 300. A BPU 110 and a battery management system (BMS) 120 may be provided inside each of the battery racks 100. Here, the BPU 110 may include one or more protection elements (e.g., fuses and / or switching devices). The BMS 120 may be a rack battery management system (RBMS).

[0055] One or more protection elements 210 (e.g., fuses and / or switching devices) may be included inside the BCP 200. One or more protection elements 310 (e.g., fuses and / or switching devices) may be disposed on the connection path between the PCS 300 and the BCP 200. The battery rack 100, the BCP 200, and the PCS 300 may be electrically connected to each other through connection elements 130 and 230. Here, the connection elements 130 and 230 may be formed of a conductive metal and may include, for example, one or more of a cable and a busbar.

[0056] Meanwhile, according to an embodiment, a battery system management device 400 may be connected to at least one of the plurality of BCPs 200. The 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 wired or wireless connection to manage the battery system.

[0057] Each of the protection elements 110, 210, and 310 included in the battery system 20 may have a specific limiting current value. Here, the limiting current value may be defined as a value obtained by multiplying the short-circuit capacity of the protection element by a predetermined adjustment constant (K). For example, the adjustment constant (K) may be defined as a specific value between approximately 0.8 and 1. For example, if the short-circuit capacity of a specific protection element is 100 kA and the adjustment constant (K) is 0.95, the limiting current of the protection element may be defined as 95 kA (100 kA * 0.95).

[0058] 3 is an example for the present invention, and the scope of the present invention is not limited to such a 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 a battery rack.

[0059] 4 is a flow chart 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 can be performed, for example, by a battery system management device 400. An example of the battery system management device 400 is shown in FIG.

[0060] The battery system management device 400 can define an equivalent model for the battery system 20 (S410).

[0061] According to one embodiment, a battery system may include a plurality of batteries and one or more protection elements, and may be formed into a predetermined connection structure. Here, the protection elements may be disposed at one or more positions selected from the group consisting of an input / output side of a battery, a connection point of a battery, and a connection point of a battery group. Meanwhile, a battery may refer to a battery cell or a battery assembly.

[0062] FIG. 5 is a block diagram for explaining an equivalent model of the battery system 30 according to the embodiment of the present invention.

[0063] The battery system management device 400 can define an equivalent model of the battery system 30 that corresponds to the structure of the actual battery system 20 .

[0064] For example, the battery system management device 400 can define an equivalent model of the battery system 30 including a total of N batteries and a power conversion device, as shown in Fig. 5. Here, the 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.

[0065] The positions of the protection elements may be defined to correspond to the positions in the actual battery system. For example, the positions of the protection elements may be defined as the input / output side (A) of each battery, the parallel connection point (B) of the battery, and the parallel connection point (C) of the battery group.

[0066] Each of the protection elements included in the equivalent model may be defined with a limiting current, where the limiting current may be defined as the short-circuit capacity of the actual protection element multiplied by a predetermined adjustment constant (K).

[0067] 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 elements, and a third equivalent model for the connection elements 130, 230 that electrically connect the battery to an external device. Here, the first equivalent model may be defined as an equivalent circuit including an internal resistance (Ric) and an internal inductance (Lic) due to the characteristics of the battery, the second equivalent model may be defined as an equivalent circuit including a resistance (Rarc), a capacitor (Carc), and a switch due to the characteristics of the protection elements, and the third equivalent model may be defined as an equivalent circuit including a resistance (Rec) and an inductance (Lec) due to the length and characteristics of the connection elements 130, 230.

[0068] 4, the battery system management device 400 can calculate a short-circuit current generated in the battery system when a short circuit occurs at a specific position in the battery system using the equivalent model defined in S410 (S420). For example, the battery system management device 400 can calculate a short-circuit current generated at a specific position in the battery system when a short circuit occurs inside a battery.

[0069] 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 inside a 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.

[0070] The location of a short circuit in a battery system may be predefined. Here, the location of a short circuit may include one or more of a first location defined as inside a battery, a second location defined as between a connection point between the batteries, a third location defined as between a connection point between the batteries and a connection point between a group of batteries, and a fourth location defined as between a connection point between the group of batteries and a power converter. For example, in FIG. 5 , the location of a short circuit may be defined as one or more of inside a battery (P1), between a parallel connection point between the batteries and a parallel connection point between the battery group (P2), between a parallel connection point between the battery and a parallel connection point between the battery group (P3), and between the parallel connection point between the group of batteries and a power converter (P4).

[0071] The battery system management device 400 can calculate short-circuit currents that occur in the battery system when short circuits occur at multiple locations within the battery system. For example, the battery system management device 400 can calculate the short-circuit currents applied to each of the protection elements when a short circuit occurs at P1, and can calculate the short-circuit currents 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 currents applied to each of the protection elements when short circuits occur simultaneously at P1 and P2.

[0072] 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).

[0073] In an embodiment, the battery system management device 400 can check whether the short-circuit current exceeds the limit current for each of the protection elements included in the battery system. For example, the battery system management device 400 can compare the short-circuit current applied to each protection element with the limit current of each protection element to check whether there is a protection element whose short-circuit current exceeds the limit current for all protection elements.

[0074] The battery system management device 400 can determine the number of batteries to be included in the battery system based on the comparison result of S430 (S440). Here, the battery system management device 400 can 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 can determine that the corresponding protection element cannot handle the short-circuit current and gradually reduce the number of batteries. Conversely, if the short-circuit current applied to the protection element is smaller than the limit current of each protection element, the battery system management device 400 can determine that the corresponding protection element can withstand the short-circuit current and can maintain the current situation or attempt to gradually increase the number of batteries.

[0075] In an embodiment, the battery system management device 400 can determine the maximum number of batteries that allows all protection elements in the battery system to withstand short-circuit current.

[0076] For example, the battery system management device 400 can perform a simulation (S410 to S430) for calculating the short-circuit current for a battery system consisting of N batteries. If it is confirmed that all protective elements can withstand the short-circuit current (the short-circuit current is equal to or less than the limit current), the battery system management device 400 can perform a simulation (S410 to S430) for a battery system consisting of N+1 batteries. Here, if it is confirmed that one or more protective 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 to be N.

[0077] In an embodiment, the battery system management device 400 calculates the short-circuit current applied to each protection element for each case in which a short circuit occurs at multiple locations, and can determine the maximum number of batteries that will allow all protection elements to withstand the short-circuit current for all cases.

[0078] For example, the battery system management device 400 can perform simulations (S410-S430) for cases in which a short circuit occurs at each of P1-P4 for a battery system consisting of N batteries. If it is confirmed that all protective elements can withstand the short circuit current for all cases (the short circuit current is equal to or less than the limit current), the battery system management device 400 can perform simulations (S410-S430) for four cases for a battery system consisting of N+1 batteries. Here, if it is confirmed that one or more protective 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 to be N.

[0079] FIG. 6 is an operational flow diagram of a battery system management method according to another embodiment of the present invention.

[0080] The battery system management device 400 can define an equivalent model for the battery system 30 including N batteries (S610).

[0081] Thereafter, the battery system management device 400 can use the equivalent model defined in S610 to calculate the short-circuit current applied to the protection element when a short circuit occurs at one position in the battery system (S620).

[0082] Here, the battery system management device 400 can calculate the short-circuit current applied to each of the multiple protection elements for each case where a short circuit occurs at one or more positions. For example, the battery system management device 400 can calculate the short-circuit current applied to each of the multiple protection elements for each case where a short circuit occurs at P1 to P4.

[0083] The battery system management device 400 can compare the short-circuit current calculated in S620 with the limit current of the protective element (S630). Here, the battery system management device 400 can compare the short-circuit current of the protective element with the limit current for all of a plurality of cases.

[0084] If it is confirmed that the short-circuit current of all protective elements is below the limit current for all multiple cases (Y in S640), the battery system management device 400 changes the number of batteries included in the battery system to N+1 and redefines the equivalent model (S610), and can calculate the short-circuit current using the redefined equivalent model (S620).

[0085] Here, if one or more protection elements are detected in which the short-circuit current exceeds the limit current (N in S640), the battery system management device 400 can determine the maximum number of batteries in the battery system to be N (S650).

[0086] FIG. 7 is a circuit diagram for explaining an equivalent model of a battery according to an embodiment of the invention.

[0087] 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 elements 130, 230 that electrically connect the battery and an external device. Here, the battery system management device 400 can calculate the short-circuit current value using the equivalent model.

[0088] The first equivalent model for the battery may be defined as an equivalent circuit that reflects the characteristics of the battery.

[0089] For example, the first equivalent model may include an equivalent circuit of the 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 resistance (Ri), a second resistance (Rd) connected in parallel with each other, and a capacitor (Cd) are connected in series. Also, 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.

[0090] A second equivalent model for the protection element may be defined as a circuit including a resistor (Rarc), a capacitor (Carc) and a switch.

[0091] Meanwhile, in a battery system, voltage and current characteristics may change based on the occurrence of a short circuit, and accordingly, a protection element (e.g., a fuse) may change from a first state (melting) to a second state (clearing) based on the occurrence of a short circuit.

[0092] 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.

[0093] In order to embody the fusing characteristics of such a protection element, the second equivalent model according to an embodiment of the present invention may be embodied in a circuit including a resistor (Rarc), a capacitor (Carc), and a switch, as shown in FIG.

[0094] A third equivalent model for the connection element 130, 230 may be defined as an RL circuit in which a resistor (Rec) and an inductor (Lec) are connected in series, where the resistor (Rec) and the inductor (Lec) may be defined as the resistance and inductance due to the length and characteristics of the connection element 130, 230 (e.g., a cable or bus bar).

[0095] The equivalent model according to an embodiment of the present invention is defined to reflect the characteristics of the connection elements 130, 230 according to the connection structure of the battery system, so that the battery system management device 400 can calculate a short-circuit current that reflects the difference in the time constant of each connection element 130, 230, thereby more accurately determining the optimal number of batteries that may be applied to the battery system.

[0096] 8 and 9 are examples of battery systems to which the present invention may be applied according to one embodiment. The battery system shown in Fig. 8 may be configured to include multiple battery racks 100 as B-Links, and the battery system shown in Fig. 9 may be configured to include a PCS 300 including multiple AC / DC inverters and multiple DC-Links.

[0097] 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 multiple B-Links. The E-Link may include one or more protection elements (e.g., fuses or switching devices). The multiple B-Links may be connected in parallel to the E-Link. Here, each B-Link may include multiple battery racks 100 connected in parallel.

[0098] 8, the B-Link may include a BCP 200 and a plurality of battery racks 100. Here, the plurality of battery racks 100 may be 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.

[0099] The BCP 200 and the BPU 110 may be equipped with one or more internal protection elements (eg, fuses and / or switching devices).

[0100] The battery system management device 400 can define an equivalent model for the battery system shown in Figures 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.

[0101] Here, the battery system management device 400 calculates the short-circuit current applied to each of the protection elements, reflecting the time constant characteristics of the connection elements 130 and 230 due to a predetermined connection structure, for each case in which a short circuit occurs at multiple positions, and can determine the maximum number of batteries that will allow all protection elements to withstand the short-circuit current for all cases.

[0102] In the battery systems shown in Figures 8 and 9, the locations where short-circuit current occurs may include one or more of the following locations, similar to the case of Figure 5: inside 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).

[0103] Fig. 10 is an operational flow diagram of a battery system management method according to still another embodiment of the present invention. Figs. 11 to 15 are block diagrams for explaining simulation results for first to fifth cases. Below, a method for determining the optimal number of batteries for the battery systems shown in Figs. 8 and 9 will be described with reference to Figs. 10 to 15.

[0104] 10, the battery system management device 400 may sequentially perform a simulation to calculate a short circuit current for each case where a short circuit occurs at a plurality of positions, and may sequentially check the simulation results to determine the maximum number of batteries to be configured in the battery system. For example, the battery system management device 400 may sequentially perform the simulation from the highest position to the lowest position in the battery system structure. For example, the simulation to calculate the short circuit current may be performed in the order of P4, P3, P2, and P1.

[0105] Referring to FIG. 10, the battery system management device 400 can use an equivalent model of a battery system including N batteries to perform a simulation to calculate a short circuit current for the case where a short circuit occurs at P4 (first case) (S1010).

[0106] In one embodiment, if a short circuit occurs at P4, which is the structurally highest position of the battery system, as shown in Fig. 11, a large short-circuit current applied from DC-Links #1 to #3 flows to 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 shown 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 their respective positions.

[0107] The battery system management device 400 can compare the short-circuit current for each protective element calculated as a result of the simulation with the limit current of each protective element.

[0108] If the comparison confirms that the short-circuit currents of all protection elements are equal to or less than the limit current (Y in S1020), the battery system management device 400 can change the number of battery racks 100 included in the battery system (e.g., increase by one), redefine the equivalent model, 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 increased short-circuit current due to short circuits at their respective positions, increases the number of battery racks 100, redefines the equivalent model, and performs a simulation.

[0109] If one or more protective elements whose short-circuit current exceeds the limit current are detected (N in S1020), the battery system management device 400 can determine the maximum number of battery racks 100 that can be applied to the battery system to be N.

[0110] Next, the battery system management device 400 may proceed with the next step of simulation for calculating the short circuit current for the case where a short circuit occurs at P3 (second case) (S1030).

[0111] If a short circuit occurs at P3, a large short-circuit current applied from DC-Links #2 and #3 and the B-Link of DC-Link #1 will flow to the E-Link side of DC-Link #1, as shown in Figure 12. At this time, each of the protection elements configured in the battery system must be able to withstand the short-circuit current that occurs.

[0112] The battery system management device 400 can compare the short-circuit current for each protective element calculated as a result of the simulation with the limit current of each protective element.

[0113] If one or more protective elements are detected whose short-circuit current exceeds the limit current (N in S1040), the battery management device 400 determines that one or more protective elements cannot withstand the generated short-circuit current, changes the number of battery racks 100 included in the battery system (e.g., reduces it by one), redefines the equivalent model, and performs a simulation using the redefined equivalent model.

[0114] On the other hand, if it is confirmed that the short-circuit currents of all the protection elements are below the limit current (Y in S1040), the battery system management device 400 can proceed with a simulation to calculate the short-circuit current for the case where a short circuit occurs at P2 (third case) (S1050).

[0115] If a short circuit occurs at P2, a large short-circuit current applied from DC-Links #2 and #3 and the battery rack 100 of B-Link #2 of DC-Link #1 will flow to the BCP side of B-Link #2, as shown in Figure 13. At this time, each of the protection elements configured in the battery system must be able to withstand the short-circuit current that occurs at each position.

[0116] The battery system management device 400 can compare the short-circuit current for each protective element calculated as a result of the simulation with the limit current of each protective element.

[0117] If one or more protective elements are detected whose short-circuit current exceeds the limit current (N in S1060), the battery system management device 400 determines that one or more protective elements cannot withstand the generated short-circuit current, changes the number of battery racks 100 included in the battery system (e.g., reduces it by one), redefines the equivalent model, and performs a simulation using the redefined equivalent model.

[0118] If it is confirmed that the short-circuit currents of all protection elements are below the limit current (Y in S1060), the battery system management device 400 can proceed with a simulation to calculate the short-circuit current for the case where a short circuit occurs at P1 (fourth case) as the next step (S1070).

[0119] If a short circuit occurs at P1, a large short-circuit current applied from DC-Links #2 and #3 and other battery racks 100 on B-Link #2 of DC-Link #1 will flow to the BPU 110 side of the rack where the short-circuit current occurred, as shown in Figure 14. In this case, each of the protection elements configured in the battery system must be able to withstand the short-circuit current that occurs at each position.

[0120] The battery system management device 400 can compare the short-circuit current for each protective element calculated as a result of the simulation with the limit current of each protective element.

[0121] If one or more protective elements are detected whose short-circuit current exceeds the limit current (N in S1080), the battery system management device 400 can change the number of battery racks 100 included in the battery system (e.g., reduce by one) and redefine the equivalent model, and perform a simulation using the redefined equivalent model.

[0122] If it is confirmed that the short-circuit currents of all protection elements are below the limit current (Y in 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 for the battery system (S1090).

[0123] Meanwhile, the battery system management device 400 can additionally perform simulations for cases where short circuits occur at multiple locations simultaneously or at regular time intervals, and calculate the optimal number of batteries based on the simulation results.

[0124] For example, as shown in FIG. 15, the battery system management device 400 can additionally perform a simulation for calculating a short-circuit current for a case (fifth case) in which short circuits occur simultaneously at P3 and P3'.

[0125] If short circuits occur simultaneously at P3 and P3', a large short-circuit current will flow through the E-Link of DC-Link #1 and the E-Link of DC-Link #3. In this case, each protection element configured in the battery system must be able to withstand the short-circuit current generated at its respective 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.

[0126] FIG. 16 is a block diagram for explaining the structure of a battery system derived from the present invention.

[0127] 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 connection structure.

[0128] 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).

[0129] 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), resulting in relatively low inductance and resistance. As a result, the symmetrical parallel connection structure (B) has a relatively small time constant and a relatively high total short-circuit current. Conversely, the asymmetrical parallel connection structure (A) has a relatively low total short-circuit current and can include more battery racks 100 than the symmetrical parallel connection structure (B).

[0130] FIG. 17 is a block diagram of a battery system management device 400 according to an embodiment of the present invention.

[0131] The battery system management device 400 may include at least one processor 410, a memory 420 that stores at least one instruction executed by the processor, and a transceiver 430 that is connected to a network and communicates with the network. 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. The components included in the battery system management device 400 are connected to each other by a bus 470 and can communicate with each other.

[0132] The processor 410 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which the method according to the present invention is performed. The memory (or storage device) may be composed of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory may be composed of at least one of a read-only memory (ROM) and a random access memory (RAM).

[0133] Meanwhile, the at least one instruction executed by the processor may include an instruction to define an equivalent model for a battery system formed in a predetermined connection structure including a plurality of batteries and one or more protection elements; an instruction to calculate, using the equivalent model, a short-circuit current generated in the battery system when a short circuit occurs at a specific position within the battery system, reflecting the time constant characteristics of the connection elements due to the predetermined connection structure; an instruction to compare the calculated short-circuit current with a limit current of the protection element; and an instruction to determine the number of batteries to be provided in the battery system based on the comparison result.

[0134] The protection element may be disposed at one or more of the input / output side of the battery, the connection point of the battery, and the connection point of the battery group.

[0135] The instruction to define the equivalent model may include an instruction to define 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 that electrically connects the battery and an external device, where the third equivalent model may be defined as an RL equivalent circuit having a resistance and inductance corresponding to the length of the connection element.

[0136] The command to calculate the short-circuit current may include a command to calculate a short-circuit current applied to each of the plurality of protection elements, when a short circuit occurs at one or more positions, by reflecting the time constant characteristics of the connection elements due to the predetermined connection structure.

[0137] The location where the short circuit occurs may include one or more of a first location defined as inside the battery, a second location defined as between the battery and battery connection points, a third location defined as between the battery connection points and the battery group connection points, and a fourth location defined as between the battery group connection points and the power conversion device.

[0138] The instruction to compare the calculated short circuit current with the limit current of the protection element may include an instruction to confirm, for each of the multiple protection elements, whether the short circuit current exceeds a limit current defined based on the short circuit capacity of the protection element.

[0139] The instruction to determine the number of batteries may include an instruction to determine the maximum number of batteries that prevents the short circuit current applied to each of the protection elements from exceeding the limit current of each of the protection elements.

[0140] The instruction to calculate the short circuit current may include an instruction to calculate the short circuit current applied to each of the protection elements, for each case where a short circuit occurs at a plurality of positions, by reflecting the time constant characteristics of the connection elements according to the predetermined connection structure. Here, the instruction to determine the number of batteries may include an instruction to determine the maximum number of batteries that prevents the short circuit current applied to each of the protection elements from exceeding the limit current of each of the protection elements, for all cases.

[0141] The instruction to determine the maximum number of batteries may include an instruction to change the number of batteries included in the battery system and redefine the equivalent model depending on the result of comparing the short-circuit current with the limit current, and an instruction to recalculate the short-circuit current based on the redefined equivalent model.

[0142] Meanwhile, the operation of the method according to the embodiment of the present invention may be embodied as a computer-readable program or code on a computer-readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Furthermore, the computer-readable recording medium may be distributed among computer systems connected via a network, so that the computer-readable program or code may be stored and executed in a distributed manner.

[0143] Some aspects of the invention have been described in the context of an apparatus, but they may also be described in terms of a corresponding method, where a block or apparatus corresponds to a method step or feature of a method step. Similarly, aspects described in the context of a method may be described in terms of a corresponding block or item or feature of a corresponding apparatus. Some or all of the method steps may be performed by (or using) a hardware apparatus, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most important method steps may be performed by such an apparatus.

[0144] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and variations can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. [Explanation of symbols]

[0145] 100: Battery rack 200:BCP 300:PCS 400: Battery system management device

Claims

1. at least one processor capable of communicating with the battery system; and a memory coupled to the at least one processor and storing at least one instruction to be executed by the processor; The at least one instruction: instructions for defining an equivalent model for a battery system including a plurality of batteries and one or more protection elements configured in a predetermined connection configuration; a command to calculate, using the equivalent model, a short-circuit current generated in the battery system, when a short circuit occurs at a specific position in the battery system, while reflecting the time constant characteristics of connection elements due to the predetermined connection structure; an instruction to compare the calculated short circuit current with a limit current of the protection device; and A battery system management device including instructions for determining the number of batteries to be included in the battery system based on a result of the comparison.

2. The protection element is The battery system management device according to claim 1 , which is disposed at one or more of the input / output side of a battery, a connection point of a battery, and a connection point of a battery group.

3. The instructions defining the equivalent model include:

2. The battery system management device of claim 1, further comprising instructions 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 element, and a third equivalent model for a connection element that electrically connects the battery to an external device.

4. The third equivalent model is The battery system management device according to claim 3 , wherein the connection element is defined as an RL equivalent circuit having a resistance and an inductance corresponding to the length of the connection element.

5. The instruction to calculate the short circuit current is 2. The battery system management device according to claim 1, further comprising an instruction to calculate a short-circuit current applied to each of the plurality of protection elements, when a short circuit occurs at one or more positions, by reflecting the time constant characteristics of the connection elements due to the predetermined connection structure.

6. The position where the short circuit occurs is 6. The battery system management device of claim 5, including one or more of a first position defined as inside the battery, a second position defined as between the battery and battery connection points, a third position defined as between the battery connection points and the battery group connection points, and a fourth position defined as between the battery group connection points and the power conversion device.

7. The comparing instruction is The battery system management device according to claim 5 , further comprising an instruction for confirming, for each of the plurality of protection elements, whether or not a short-circuit current exceeds a limit current defined based on the short-circuit capacity of the protection element.

8. The instruction to determine the number of batteries includes: The battery system management device according to claim 1 , further comprising instructions for determining a maximum number of batteries that will prevent a short-circuit current applied to each of the protection elements from exceeding a limit current of each of the protection elements.

9. The instruction to calculate the short circuit current is a command to calculate a short-circuit current to be applied to each of the protection elements, for each case where a short circuit occurs at a plurality of positions, while reflecting the time constant characteristics of the connection elements due to the predetermined connection structure; The instruction to determine the number of batteries includes:

9. The battery system management device according to claim 8, further comprising instructions for determining, for all cases, the maximum number of batteries that will prevent the short-circuit current applied to each of the protection elements from exceeding the limit current of each of the protection elements.

10. The instruction to determine the maximum number of batteries is A command to change the number of batteries included in the battery system and redefine the equivalent model according to the comparison result between the short circuit current and the limiting current; and The battery system management device according to claim 9 , further comprising an instruction to recalculate the short circuit current based on the redefined equivalent model.

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

12. The protection element is The battery system management method according to claim 11 , wherein the sensor is disposed at one or more of the input / output side of the battery, the connection point of the battery, and the connection point of the battery group.

13. The step of defining the equivalent model comprises:

12. The battery system management method according to claim 11, further comprising 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 connection element that electrically connects the battery and an external device.

14. The third equivalent model is The battery system management method according to claim 13 , wherein the connection element is defined as an RL equivalent circuit having a resistance value and an inductance corresponding to the length of the connection element.

15. The step of calculating the short circuit current includes:

12. The battery system management method according to claim 11, further comprising a step of calculating a short-circuit current applied to each of the plurality of protection elements, when a short circuit occurs at one or more positions, by reflecting a time constant characteristic of a connection element due to the predetermined connection structure.

16. The position where the short circuit occurs is 16. The battery system management method of claim 15, including one or more of a first position defined as inside the battery, a second position defined as between a connection point between the battery and a connection point between the battery group, a third position defined as between a connection point between the battery and a connection point between the battery group and a power conversion device.

17. The comparing step includes: The battery system management method according to claim 15, further comprising the step of checking, for each of the plurality of protection elements, whether or not the short-circuit current exceeds a limit current defined based on the short-circuit capacity of the protection element.

18. The step of determining the number of batteries includes: The battery system management method according to claim 11, further comprising the step of determining a maximum number of batteries that prevents a short-circuit current applied to each of the protection elements from exceeding a limit current of each of the protection elements.

19. The step of calculating the short circuit current includes: a step of calculating a short-circuit current applied to each of the protection elements, for each case where a short circuit occurs at a plurality of positions, while reflecting the time constant characteristics of the connection elements due to the predetermined connection structure; The step of determining the number of batteries includes:

20. The battery system management method according to claim 18, further comprising the step of determining, for all cases, the maximum number of batteries that will prevent the short-circuit current applied to each of the protection elements from exceeding the limit current of each of the protection elements.

20. The step of determining the maximum number of batteries includes: A step of changing the number of batteries included in the battery system and redefining the equivalent model according to the comparison result between the short-circuit current and the limiting current; and 20. The battery system management method according to claim 19, further comprising the step of recalculating the short circuit current based on the redefined equivalent model.

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