Battery management device and its operating method

Abstract

A battery management device according to one embodiment disclosed herein includes: an information acquisition unit that measures the cell current of each of a plurality of battery cells; a controller that calculates the usable capacity of each of the plurality of battery cells based on the cell current, extracts a reference battery cell having the minimum usable capacity among the usable capacities of each of the plurality of battery cells, sets the minimum usable capacity as the reference capacity, sets a reference DOD which is a DOD value set within an arbitrary DOD (Depth of Discharge) range, calculates a first reference voltage corresponding to the reference DOD of the reference battery cell, and balances each of the plurality of battery cells based on the first reference voltage.

Description

Technical Field

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[0001] The present invention claims the benefit of priority based on Korean Patent Application No. 10-2023-0102876 filed on August 7, 2023, and all the contents disclosed in the documents of the Korean patent application are incorporated herein by reference. The embodiments disclosed in this document relate to a battery management device and an operating method thereof.

Background Art

[0002] When a battery pack is used for a long time, the degree of deterioration and the internal resistance value of each of the plurality of battery cells are different, and cell deviation between the plurality of battery cells may occur. Here, the cell deviation may mean a deviation in the available capacity (Ah) and a deviation in the cell voltage. As the cell deviation increases, overcharging or over-discharging may occur, and thus, a problem may occur in that the capacity of the entire battery pack decreases and the lifespan becomes shorter.

[0003] To solve such problems, a battery system performs cell balancing to reduce the deviation between cells. The battery system can calculate a cell balancing current value based on an open circuit voltage (OCV) value and perform cell balancing during a balancing time calculated based on the balancing current value.

[0004] On the other hand, when performing cell balancing based on a point where the SOC of the battery cell is 0% or a point where the SOC is 100%, there is a problem in that the deterioration of the battery cell is promoted by repeatedly using the lower or upper end of the SOC of the battery cell.

Summary of the Invention

Problems to be Solved by the Invention

[0006] One objective of the embodiments disclosed in this document is to provide a battery management device and a method for operating the same that can adjust the frequency of use according to the cell voltage interval of a battery cell.

[0007] The technical problems of the embodiments described herein are not limited to those mentioned above, and other technical problems not mentioned can be clearly understood by a person ordinary to the art to which the present invention pertains from the following description. [Means for solving the problem]

[0008] A battery management device according to one embodiment disclosed in this document includes: an information acquisition unit that measures the cell current of each of a plurality of battery cells; a controller that calculates the usable capacity of each of the plurality of battery cells based on the cell current, extracts a reference battery cell having the minimum usable capacity among the usable capacities of each of the plurality of battery cells, sets the minimum usable capacity as the reference capacity, sets a reference DOD which is a DOD value set within an arbitrary DOD (Depth of Discharge) range, calculates a first reference voltage corresponding to the reference DOD of the reference battery cell, and balances each of the plurality of battery cells based on the first reference voltage.

[0009] According to one embodiment, the controller can adjust the cell voltage of each of the plurality of battery cells so that the comparison voltage corresponding to the reference DOD of each of the plurality of battery cells corresponds to the first reference voltage.

[0010] According to one embodiment, the controller can set the operating voltage range of each of the plurality of battery cells so that the operating capacity of each of the plurality of battery cells corresponds to the reference capacity.

[0011] According to one embodiment, the plurality of battery cells include a first battery cell and a second battery cell having a different usable capacity from the first battery cell, and the operating voltage range of the first battery cell may differ from the operating voltage range of the second battery cell.

[0012] According to one embodiment, the usable capacity of the first battery cell is smaller than the usable capacity of the second battery cell, and the operating voltage range of the first battery cell can include the operating voltage range of the second battery cell.

[0013] According to one embodiment, the controller can set the modified State of Charge (SOC) for each of the plurality of battery cells based on the operating voltage range of each of the plurality of battery cells. According to one embodiment, the operating capacities corresponding to the operating voltage of each of the plurality of battery cells can be the same.

[0014] According to one embodiment, the controller can balance each of the plurality of battery cells if the difference between the maximum usable capacity and the minimum usable capacity of the plurality of battery cells is greater than or equal to a value that has already been set. According to one embodiment, the reference DOD can be defined as a state in which the DOD is 50% or half of the usable capacity of the battery cell.

[0015] A battery management method according to one embodiment disclosed herein includes the steps of: calculating the usable capacity of each of a plurality of battery cells; extracting a reference battery cell having the minimum usable capacity from the usable capacities of each of the plurality of battery cells, setting the minimum usable capacity as the reference capacity, setting a reference DOD which is a DOD value set within an arbitrary DOD (Depth of Discharge) range, calculating a first reference voltage corresponding to the reference DOD of the reference battery cell; and balancing each of the plurality of battery cells based on the first reference voltage.

[0016] According to one embodiment, the process may further include a step of determining whether the difference between the maximum usable capacity and the minimum usable capacity of the plurality of battery cells is greater than or equal to a previously set value, prior to the balancing step.

[0017] According to one embodiment, the balancing step may include adjusting the cell voltage of each of the plurality of battery cells so that the comparison voltage corresponding to the reference DOD of each of the plurality of battery cells corresponds to the first reference voltage.

[0018] According to one embodiment, the balancing step may include setting the operating voltage range of each of the plurality of battery cells such that the operating capacity of each of the plurality of battery cells corresponds to the reference capacity.

[0019] According to one embodiment, the balancing step may include setting a modified State of Charge (SOC) for each of the plurality of battery cells based on the operating voltage range of each of the plurality of battery cells.

[0020] According to one embodiment, the plurality of battery cells include a first battery cell and a second battery cell having a different usable capacity from the first battery cell, and the operating voltage range of the first battery cell may differ from the operating voltage range of the second battery cell.

[0021] According to one embodiment, the usable capacity of the first battery cell is smaller than the usable capacity of the second battery cell, and the operating voltage range of the first battery cell can include the operating voltage range of the second battery cell. According to one embodiment, the operating capacities corresponding to the operating voltage of each of the plurality of battery cells can be the same.

[0022] According to one embodiment, the reference DOD can be defined as a state in which the DOD is 50% or half of the usable capacity of the battery cell. Specific details of other embodiments are included in the detailed description and drawings. [Effects of the Invention]

[0023] The battery management device and its operation method according to the embodiments disclosed in this document can manage the available capacity of each of a plurality of battery cells by adjusting the operating voltage range of the battery cells.

[0024] The battery management device and its operation method according to the embodiments disclosed in this document can prevent overcharging and over-discharging problems of the battery cells and improve the lifespan of the battery cells by adjusting the operating voltage range of the battery cells.

[0025] The battery management device and its operation method according to the embodiments disclosed in this document can reduce the frequency of passive balancing and improve the lifespan of the battery. The effects of the battery management device and its operation method according to the disclosure of this document are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the disclosure of this document.

Brief Description of the Drawings

[0026] [Figure 1] It is a block diagram showing a battery system according to an embodiment disclosed in this document. [Figure 2] It is a diagram showing a method for a battery management device according to an embodiment disclosed in this document to balance a plurality of battery cells. [Figure 3] It is a flowchart showing a cell balancing method according to an embodiment disclosed in this document. [Figure 4] It is a flowchart specifically showing an operation of balancing each of a plurality of battery cells based on the first reference voltage in FIG. 3. [Figure 5] It is a block diagram showing a computing system that executes a cell balancing method according to an embodiment disclosed in this document. In relation to the description of the drawings, the same or similar reference numerals may be used for the same or similar components.

Modes for Carrying Out the Invention

[0027] Embodiments of the present invention are described below with reference to the accompanying drawings. However, this should be understood not as limiting the present invention to any particular embodiment, but rather as including various modifications, equivalents, and / or alternatives to embodiments of the present invention.

[0028] The embodiments and terminology used herein are not intended to limit the technical features described herein to any particular embodiment, but should be understood to include various modifications, equivalents, or substitutes of such embodiments. In relation to the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of a noun corresponding to an item may include one or more such items unless the context clearly indicates otherwise.

[0029] In this document, each phrase such as “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and “at least one of A, B, or C” may include any one of the items listed together with the applicable phrase, or any possible combination thereof. Terms such as “first,” “second,” “first,” “second,” “A,” “B,” “(a),” or “(b)” may be used simply to distinguish one component from other components and, unless otherwise stated, do not limit the component in any other respect (e.g., importance or order).

[0030] Wherever a component (e.g., the first) is referred to as being "coupled," "joined," or "connected" to another component (e.g., the second), with or without such terms, it means that the first component may be directly (e.g., wired or wirelessly) or indirectly (e.g., via the third component) connected to the other component.

[0031] Methods according to various embodiments disclosed herein may be provided in a computer program product. The computer program product may be traded as a commodity between a seller and a buyer. The computer program product may be distributed in the form of an instrument-readable storage medium (e.g., compact disc read-only memory, CD-ROM) or online (e.g., download or upload) via an application store or directly between two user devices. In the case of online distribution, at least a portion of the computer program product may be at least temporarily stored or temporarily generated in an instrument-readable storage medium such as the memory of a manufacturer's server, an application store server, or an intermediary server.

[0032] According to the embodiments disclosed herein, each of the aforementioned components (e.g., a module or a program) may include one or more individuals, and some of the individuals may be separated and arranged in other components. According to the embodiments disclosed herein, one or more of the aforementioned components or operations may be omitted, or one or more other components or operations may be added. Alternatively or additionally, multiple components (e.g., a module or a program) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the multiple components in the same or similar manner as those performed by the components of the multiple components before the integration. According to the embodiments disclosed herein, operations performed by a module, program, or other component may be performed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be performed in a different order, omitted, or one or more other operations may be added.

[0033] Figure 1 is a block diagram showing a battery system according to one embodiment disclosed in this document. Referring to Figure 1, the battery system 1 may include a battery pack 10 and a higher-level controller 20.

[0034] The battery pack 10 may include a plurality of battery cells 100, a battery management device 200, a sensor 300, and a switching unit 400. The plurality of battery cells 100 may be a collection of battery cells, each containing at least two or more battery cells. Each of the battery cells included in the plurality of battery cells 100 may be connected to one another in series or in parallel.

[0035] The multiple battery cells 100 may include two or more battery cells. According to one embodiment, the multiple battery cells 100 may include a first battery cell 110 and a second battery cell 120. Here, the first battery cell 110 and the second battery cell 120 may be different battery cells from each other.

[0036] The usable capacities of the battery cells included in the multiple battery cells 100 can differ from one another. Here, usable capacity may mean the amount of electrons that a battery cell can store. According to the embodiment, the degradation rate of each battery cell included in the multiple battery cells 100 can differ from one another due to the influence of production deviations, temperature, or voltage. According to the embodiment, due to the difference in the degradation rates of each battery cell included in the multiple battery cells 100, the usable capacities of each battery cell included in the multiple battery cells 100 can differ from one another.

[0037] The usable capacity of the first battery cell 110 and the usable capacity of the second battery cell 120, which are included in the multiple battery cells 100, can be different from each other. Here, the usable capacity of the first battery cell 110 can be defined as a [Ah]. Also, the usable capacity of the second battery cell 120 can be defined as b [Ah]. And a and b can be different from each other.

[0038] According to the embodiment, the usable capacity of the first battery cell 110 may be smaller than the usable capacity of the second battery cell 120. That is, the usable capacity a [Ah] of the first battery cell 110 may be smaller than the usable capacity b [Ah] of the second battery cell 120.

[0039] The battery management device 200 can manage the battery pack 10. The battery management device 200 can manage each of the multiple battery cells 100 based on information from each of the multiple battery cells 100. According to the embodiment, the battery management device 200 can monitor the voltage, current, temperature, etc., of the battery pack 10 and prevent overcharging and over-discharging. The battery management device 200 is also an interface for receiving information from multiple battery cells 100 and can include multiple terminals for receiving information input. On the other hand, the battery management device 200 can also control the ON / OFF state of the switching unit 400 and can be connected to multiple battery cells 100 to monitor the state of each of the multiple battery cells 100.

[0040] The battery management device 200 may include an information acquisition unit 210 and a controller 220. Here, the information acquisition unit 210 can acquire the current of each of the multiple battery cells 100. As a result, the information acquisition unit 210 can acquire current information of the first battery cell 110 and the second battery cell 120. According to the embodiment, the information acquisition unit 210 may be directly connected to the first battery cell 110 and the second battery cell 120 to acquire the current of the first battery cell 110 and the second battery cell 120, or it may receive current information acquired by the sensor 300 from the sensor 300. In addition, the information acquisition unit 210 can transmit the current information of the multiple battery cells 100 to the controller 220.

[0041] The controller 220 can calculate the usable capacity of each of the multiple battery cells 100. According to this embodiment, the controller 220 can calculate the usable capacity of the battery cells based on current information. Specifically, the controller 220 can calculate the usable capacity of the first battery cell 110 based on the current information of the first battery cell 110 transmitted from the information acquisition unit 210, and calculate the usable capacity of the second battery cell 120 based on the current information of the second battery cell 120. According to this embodiment, the usable capacity of the first battery cell 110 calculated by the controller 220 may be a [Ah], and the usable capacity of the second battery cell 120 may be b [Ah].

[0042] The controller 220 can balance multiple battery cells 100. Specifically, the controller 220 can balance the first battery cell 110 and the second battery cell 120. The balancing operation of the controller 220 will be explained in detail with reference to Figure 2.

[0043] The controller 220 can compare the difference between the maximum and minimum usable capacities of multiple battery cells 100 with a pre-set value. That is, the controller 220 can compare the usable capacities of each of the multiple battery cells 100 and select the maximum and minimum usable capacities. The controller 220 can also calculate the maximum and minimum usable capacities. Then, the controller 220 can compare the difference between the maximum and minimum usable capacities with a pre-set value. Here, the pre-set value can be determined based on the specifications of the battery cells included in the multiple battery cells 100.

[0044] The controller 220 can perform cell balancing if the difference between the maximum usable capacity and the minimum usable capacity of the multiple battery cells 100 is greater than or equal to a previously set value. The controller 220 can refrain from performing cell balancing if the difference between the maximum usable capacity and the minimum usable capacity is less than a previously set value.

[0045] According to the embodiment, the controller 220 can provide the user with the balancing results. When the controller 220 has balanced multiple battery cells 100, it can provide the user with information related to the balancing. For example, the controller 220 may provide information related to the balancing to the user terminal via a communication unit (not shown), or it may provide information related to the balancing via a display provided in the vehicle or charger, etc.

[0046] The sensor 300 can acquire information from multiple battery cells 100. The sensor 300 is connected to multiple battery cells 100 and can acquire information from multiple battery cells 100. The sensor 300 can then transmit the information acquired from the multiple battery cells 100 to the battery management device 200. According to this embodiment, the sensor 300 may have the same configuration as the information acquisition unit 210 included in the battery management device 200. According to this embodiment, the sensor 300 may be configured to acquire different information from the information acquisition unit 210.

[0047] The switching unit 400 can control the current flow of the multiple battery cells 100. Specifically, the switching unit 400 is connected in series with the multiple battery cells 100 and the first terminal side and / or second terminal side of the multiple battery cells 100, and can control the charge and discharge current flow of the first battery cell 110. According to the embodiment, the switching unit 400 may include at least one relay, electromagnetic contactor, etc., based on the specifications of the battery pack 10.

[0048] The higher-level controller 20 can transmit control signals to the battery management device 200 for the first battery cell 110. This allows the battery management device 200 to operate based on the signals applied from the higher-level controller 20.

[0049] Figure 2 shows a method by which a battery management device according to one embodiment disclosed in this document balances multiple battery cells. Referring to Figure 2, the controller 220 can balance multiple battery cells 100. That is, the controller 220 can balance the first battery cell 110 and the second battery cell 120. Figure 2 shows an illustrative example of cell balancing of two battery cells (i.e., the first battery cell 110 and the second battery cell 120), but the content described later can be applied substantially similarly to cell balancing of two or more battery cells.

[0050] The controller 220 can extract a reference battery cell having the minimum usable capacity. That is, the controller 220 can compare the usable capacities of each of the multiple battery cells 100 and extract a reference battery cell having the minimum usable capacity. For example, the reference battery cell having the minimum usable capacity may be the first battery cell 110.

[0051] The controller 220 can define the usable capacity of the reference battery cell as the reference capacity. This allows the reference capacity to be defined as the usable capacity of the first battery cell 110. For example, the reference capacity can be defined as a [Ah].

[0052] Furthermore, the controller 220 can set the remaining battery cells from the multiple battery cells 100, excluding the reference battery cell, as the target battery cell. For example, the target battery cell may be the second battery cell 120.

[0053] For the sake of explanation, we will assume that the reference battery cell is the first battery cell 110, and the target battery cell is the second battery cell 120. The controller 220 can set a reference DOD (Depth of Discharge) for the first battery cell 110. Here, the reference DOD may mean a DOD value set within any DOD range of the battery cell, and may include, for example, a DOD value arbitrarily set by the user between 30% and 70%.

[0054] According to the embodiment, the reference DOD can be set to the central value of the usable capacity. Here, the central value of the usable capacity can be defined as half of the usable capacity of the battery cell. In this case, the reference DOD of the first battery cell 110 may be a / 2 [Ah], which is half of the usable capacity of the first battery cell 110.

[0055] The controller 220 can acquire a first reference voltage corresponding to the reference DOD of the first battery cell 110. The controller 220 can also acquire a second reference voltage corresponding to the reference DOD of the second battery cell 120.

[0056] The controller 220 can balance each of the multiple battery cells 100 based on a first reference voltage. The controller 220 can adjust the cell voltage of the second battery cell 120 based on the first reference voltage of the first battery cell 110 and balance the second battery cell 120. Specifically, the controller 220 can sequentially adjust the cell voltage of the second battery cell 120 and balance the second battery cell 120.

[0057] First, the controller 220 can temporarily adjust the cell voltage of the second battery cell 120. The controller 220 can adjust the cell voltage of the second battery cell 120 so that the second reference voltage of the second battery cell 120 corresponds to the first reference voltage. That is, the controller 220 can maintain the operating voltage range of the first battery cell 110, which is the reference battery cell, and temporarily adjust the operating voltage range of the second battery cell 120, which is the target battery cell. According to the embodiment, the operating voltage range may mean from the voltage when the battery cell is fully discharged to the voltage when it is fully charged. The operating voltage range of the first battery cell 110 can be defined as the first operating voltage range (V1). The operating voltage range of the second battery cell 120 before the primary voltage adjustment can be defined as the second operating voltage range (V2). The operating voltage range of the second battery cell 120 after the primary voltage adjustment can be defined as the third operating voltage range (V3).

[0058] Here, the primary voltage adjustment may be an adjustment that changes the start and end points of the operating voltage range while maintaining the same magnitude of the operating voltage range. That is, the magnitudes of the second operating voltage range (V2) and the third operating voltage range (V3) may be the same, the start point of the third operating voltage range (V3) may be smaller than the start point of the second operating voltage range (V2), and the end point of the third operating voltage range (V3) may be smaller than the end point of the second operating voltage range (V2).

[0059] The controller 220 can maintain the first operating voltage range (V1) and adjust the second operating voltage range (V2) to the third operating voltage range (V3) so that the second reference voltage of the second battery cell 120 corresponds to the first reference voltage. This allows the reference DOD of the first battery cell 110 to correspond to the reference DOD of the second battery cell 120.

[0060] The controller 220 can secondarily adjust the operating voltage range of the second battery cell 120. The controller 220 can adjust the operating voltage range of the second battery cell 120 so that its usable capacity corresponds to the usable capacity of the first battery cell 110.

[0061] Since the cell voltage and capacity of the battery cells correspond to each other, the operating voltage range of the battery cells can correspond to the usable capacity of the battery cells. As a result, the controller 220 can adjust the usable capacity of the second battery cell 120 by adjusting the operating voltage range of the second battery cell 120. In other words, the controller 220 can reduce the usable capacity of the second battery cell 120 by reducing the operating voltage range of the second battery cell 120.

[0062] The controller 220 can adjust the third operating voltage range (V3) of the second battery cell 120 so that the usable capacity of the second battery cell 120 corresponds to the usable capacity of the first battery cell 110. In other words, the controller 220 can reduce the third operating voltage range (V3) of the second battery cell 120 so that the usable capacity corresponding to the operating voltage range of the second battery cell 120 corresponds to the usable capacity of the first battery cell 110.

[0063] In other words, the controller 220 can reduce the operating voltage range of the second battery cell 120 so that the usable capacity b [Ah] of the second battery cell 120 corresponds to the usable capacity a [Ah] of the first battery cell 110.

[0064] Specifically, the controller 220 can reduce the third operating voltage range (V3) of the second battery cell 120 by limiting the upper adjustment range (V6) and lower adjustment range (V5) of the third operating voltage range (V3) of the second battery cell 120. For example, the controller 220 can increase the starting point of the third operating voltage range (V3) by the lower adjustment range (V5) and decrease the ending point of the third operating voltage range (V3) by the upper adjustment range (V6). According to the embodiment, the size of the upper adjustment range (V6) and the size of the lower adjustment range (V5) may be the same, but are not limited to this. According to the embodiment, the sum of the fourth operating voltage range (V4), the lower adjustment range (V5), and the upper adjustment range (V6) may be the same as the third operating voltage range (V3).

[0065] The operating voltage range of the second battery cell 120 after secondary adjustment can be changed to the fourth operating voltage range (V4). In other words, the operating voltage range of the second battery cell 120 can be adjusted from the third operating voltage range (V3) to the fourth operating voltage range (V4) by secondary adjustment.

[0066] According to the embodiment, the fourth operating voltage range (V4) can be different from the first operating voltage range (V1). That is, the fourth operating voltage range (V4), which is the operating voltage range of the second battery cell 120 after secondary adjustment, can be different from the first operating voltage range (V1), which is the operating voltage range of the first battery cell 110. In other words, the usable capacity of the second battery cell 120 after secondary adjustment is the same as the usable capacity of the first battery cell 110, but the fourth operating voltage range (V4) can be different from the first operating voltage range (V1). According to the embodiment, the usable capacity of the first battery cell 110 and the second battery cell 120 differs before voltage adjustment due to differences in degradation rate, etc., so even if the usable capacity of the second battery cell 120 corresponds after secondary adjustment, the operating voltage ranges do not have to correspond.

[0067] According to the embodiment, the first operating voltage range (V1) may include a fourth operating voltage range (V4). That is, the starting point of the first operating voltage range (V1) may be smaller than the starting point of the fourth operating voltage range (V4), and the ending point of the first operating voltage range (V1) may be larger than the ending point of the fourth operating voltage range (V4).

[0068] The controller 220 can control the operation of the second battery cell 120 by adjusting the secondary voltage so that the second battery cell 120 does not use the capacity corresponding to the lower adjustment range (V5) and upper adjustment range (V6) of the second battery cell 120. According to the embodiment, the controller 220 can control the second battery cell 120 so that the cell voltage of the second battery cell 120 does not deviate from the starting point of the fourth operating voltage range (V4) even at maximum discharge. The controller 220 can also adjust the second battery cell 120 so that the cell voltage of the second battery cell 120 does not deviate from the ending point of the fourth operating voltage range (V4) even at maximum charge. As a result, the frequency of use of the fourth operating voltage range (V4), lower adjustment range (V5), and upper adjustment range (V6) corresponding to the third operating voltage range (V3) of the second battery cell 120 can be different.

[0069] This allows the battery system 1 to reduce the frequency of use in the upper or lower part of the battery cell's operating voltage range and increase the frequency of use in the voltage range corresponding to the middle part. This can mitigate problems such as reduced battery cell life and overcharging / over-discharging caused by frequent use of the upper and lower parts of the battery cell. In other words, the battery system 1 can improve the life of the battery cell by adjusting the frequency of use according to the battery's operating voltage.

[0070] According to the embodiment, the controller 220 can set a modified State of Charge (SOC). The controller 220 can set a modified State of Charge (SOC) for each of the multiple battery cells 100 based on the operating voltage range after balancing. The controller 220 can modify the SOC and set the modified SOC based on the operating voltage changed by primary cell voltage adjustment and secondary cell voltage adjustment.

[0071] For example, before balancing the second battery cell 120, the state of charge (SOC) corresponding to the start of the second operating voltage range (V2) may be 0%, and the SOC corresponding to the end of the second operating voltage range (V2) may be 100%.

[0072] After balancing the second battery cell 120, the controller 220 can set the corrected SOC of the second battery cell 120. The controller 220 can set the corrected SOC based on the operating voltage range of the second battery cell 120 after balancing. Specifically, the controller 220 can set the corrected SOC to 0% if the cell voltage of the second battery cell 120 corresponds to the start of the fourth operating voltage range (V4). Also, the controller 220 can set the corrected SOC to 100% if the cell voltage of the second battery cell 120 corresponds to the end of the fourth operating voltage range (V4). In other words, the controller 220 can correct the SOC based on the fourth operating voltage range (V4) and set the corrected SOC. According to the embodiment, the controller 220 may set the corrected DOD in a similar manner to setting the corrected SOC.

[0073] The controller 220 can communicate the corrected SOC to the user. According to the embodiment, the controller 220 can communicate the corrected SOC to the user for each battery cell included in the plurality of battery cells 100, or it can calculate the average of the corrected SOCs of each of the plurality of battery cells 100 and communicate the average of the corrected SOCs to the user.

[0074] The battery system 1 can reduce the frequency of passive balancing. The battery system 1 can reduce the frequency of passive balancing by performing cell balancing based on the reference DOD of the battery cell having the minimum usable capacity. In other words, the battery system 1 can reduce the frequency of passive balancing by using passive balancing only at the primary voltage adjustment stage of each of the multiple battery cells 100. As a result, the battery system 1 can prevent power consumption due to passive balancing and improve power efficiency. In addition, as a result, the battery system 1 can mitigate the risk of heat generation in the battery cells and the occurrence of fire.

[0075] Figure 3 is a flowchart showing a battery management method according to one embodiment disclosed in this document. The embodiment shown in Figure 3 is only one embodiment, and the sequence of operations in various embodiments of the present invention may differ from that shown in Figure 3. Some of the steps shown in Figure 3 may be omitted, the order of the steps may be changed, or steps may be merged.

[0076] Referring to Figure 3, the battery management method may include the following steps: calculating the usable capacity of each of the multiple battery cells 100 (S100); determining whether the difference between the maximum usable capacity and the minimum usable capacity of the multiple battery cells 100 is greater than or equal to a previously set value (S200); extracting a reference battery cell with the minimum usable capacity from among the usable capacities of each of the multiple battery cells 100, setting the minimum usable capacity as the reference capacity, setting a reference DOD (Depth of Discharge), and calculating a first reference voltage corresponding to the reference DOD of the reference battery cell (S300); and balancing each of the multiple battery cells 100 based on the first reference voltage (S400).

[0077] The operations S100 to S400 will be explained in detail below with reference to Figures 1 to 3. In operation S100, the battery management device 200 can calculate the usable capacity of each of the multiple battery cells 100. According to this embodiment, the battery management device 200 can calculate the usable capacity of each of the multiple battery cells 100 based on the current information of each of the multiple battery cells 100.

[0078] In operation S200, the battery management device 200 can determine whether the difference between the maximum usable capacity and the minimum usable capacity of the multiple battery cells 100 is greater than or equal to a previously set value.

[0079] The battery management device 200 can compare the difference between the maximum usable capacity and the minimum usable capacity of multiple battery cells 100 with a pre-set value. That is, the battery management device 200 can compare the capacities of each of the multiple battery cells 100 and select the maximum and minimum usable capacities. Furthermore, the battery management device 200 can calculate the maximum and minimum usable capacities. Then, the battery management device 200 can compare the difference between the maximum and minimum usable capacities with a pre-set value. Here, the pre-set value can be determined based on the specifications of the battery cells included in the multiple battery cells 100.

[0080] The battery management device 200 can perform operation S300 if the difference between the maximum usable capacity and the minimum usable capacity is greater than or equal to a previously set value. The battery management device 200 can terminate the battery management method if the difference between the maximum usable capacity and the minimum usable capacity is less than a previously set value.

[0081] In operation S300, the battery management device 200 can extract a reference battery cell having the minimum usable capacity from among the usable capacities of multiple battery cells 100, set the minimum usable capacity as the reference capacity, set the reference DOD (Depth of Discharge), and calculate a first reference voltage corresponding to the reference DOD of the reference battery cell.

[0082] The battery management device 200 can extract the battery cell with the minimum usable capacity. That is, the battery management device 200 can compare the usable capacities of each of the multiple battery cells 100 and extract the battery cell with the minimum usable capacity. Here, the battery cell with the minimum usable capacity can be defined as the reference battery cell.

[0083] The battery management device 200 can set a reference capacity. According to the embodiment, the battery management device 200 can define the capacity of a reference battery cell as the reference capacity. That is, the usable capacity of a battery cell having the minimum usable capacity can be defined as the reference capacity.

[0084] The battery management device 200 can set a reference DOD (Depth of Discharge) for a reference battery cell. Here, the reference DOD may be a DOD point arbitrarily set by the user between a point where the DOD is 30% and a point where it is 70%.

[0085] According to the embodiment, the user can set the center of usable capacity as a reference DOD. Here, the center of usable capacity can be defined as the point where the DOD of the battery cell is 50% or half of the usable capacity of the battery cell.

[0086] The battery management device 200 can calculate the voltage corresponding to the reference DOD of the reference battery cell. Here, the voltage corresponding to the reference DOD of the reference battery cell can be defined as the first reference voltage.

[0087] In operation S400, the battery management device 200 can balance each of the multiple battery cells 100 based on the first reference voltage. This will be explained in detail with reference to Figure 4.

[0088] Figure 4 is a flowchart that specifically illustrates the operation of balancing each of the multiple battery cells 100 based on the first reference voltage in Figure 3. Referring to Figure 4, the operation of balancing each of the multiple battery cells 100 based on a first reference voltage may include: adjusting the cell voltage of each of the multiple battery cells 100 so that the second reference voltage corresponding to the reference DOD of each of the multiple battery cells 100 corresponds to the first reference voltage (S410); setting the operating voltage range of each of the multiple battery cells 100 so that the operating capacity of each of the multiple battery cells 100 corresponds to the reference capacity (S420); and setting the modified SOC (State of Charge) of each of the multiple battery cells 100 based on the operating voltage range of each of the multiple battery cells 100 (S430).

[0089] In operation S410, the battery management device 200 can adjust the cell voltage of each of the multiple battery cells 100 so that the second reference voltage corresponding to the reference DOD of each of the multiple battery cells 100 corresponds to the first reference voltage.

[0090] The battery management device 200 can perform primary adjustment on the cell voltage of each of the multiple battery cells 100. That is, the battery management device 200 can adjust the cell voltage of each of the multiple battery cells 100 so that the voltage corresponding to the reference DOD of each of the multiple battery cells 100 corresponds to the first reference voltage. Specifically, the battery management device 200 performs passive balancing on each of the multiple battery cells 100, excluding the reference battery cell, and adjusts the cell voltage of each of the multiple battery cells 100 so that the voltage corresponding to the reference DOD of each of the multiple battery cells 100 corresponds to the first reference voltage. Here, the voltage corresponding to the reference DOD of each of the multiple battery cells 100 can be defined as the second reference voltage. In other words, the battery management device 200 can use passive balancing to adjust the second reference voltage of the multiple battery cells 100 so that it corresponds to the first reference voltage.

[0091] In operation S420, the battery management device 200 can set the operating voltage range for each of the multiple battery cells 100 so that the operating capacity of each of the multiple battery cells 100 corresponds to the reference capacity.

[0092] The battery management device 200 can secondarily adjust the cell voltages of multiple battery cells 100. The battery management device 200 can adjust the voltage of each of the multiple battery cells 100 so that the usable capacity of each of the multiple battery cells 100 corresponds to the usable capacity of the reference battery cell. Since the reference battery cell is the cell with the smallest usable capacity among the multiple battery cells 100, the battery management device 200 can adjust the usable capacity by reducing the operating voltage range of the multiple battery cells 100. That is, the battery management device 200 can reduce the operating voltage range and reduce the usable capacity of each of the multiple battery cells 100 so that the usable capacity of each of the multiple battery cells 100 corresponds to the smallest usable capacity.

[0093] Specifically, the battery management device 200 can reduce the operating voltage range of a battery cell by limiting the upper adjustment range (V6) and the lower adjustment range (V5) of the battery cell's operating voltage range. According to the embodiment, the size of the upper adjustment range (V6) and the size of the lower adjustment range (V5) may be the same. This allows the operating capacities of each battery cell included in the multiple battery cells 100 to correspond to each other.

[0094] In operation S430, the battery management device 200 can set the modified State of Charge (SOC) for each of the multiple battery cells 100 based on the operating voltage range of each of the multiple battery cells 100.

[0095] The battery management device 200 can set a modified State of Charge (SOC). The battery management device 200 can set a modified State of Charge (SOC) for each of the multiple battery cells 100 based on the operating voltage range after balancing. The battery management device 200 can modify the SOC and set the modified SOC based on the operating voltage changed by primary cell voltage adjustment and secondary cell voltage adjustment.

[0096] Figure 5 is a block diagram showing a computing system that performs a battery management method according to one embodiment disclosed in this document. Referring to Figure 5, the computing system 500 according to one embodiment disclosed in this document may include an MCU 510, a memory 520, an input / output I / F 530, and a communication I / F 540.

[0097] The MCU510 may be a processor that executes various programs stored in the memory 520 (for example, a program for calculating SOH, a program for determining which cells to perform cell balancing, etc.), processes various data including SOC and SOH of multiple battery cells through such programs, and performs the functions of the battery management device 200 as described above with reference to Figures 1 to 3.

[0098] Memory 520 can store various programs related to calculating the State of Health (SOH) of battery cells and determining which cells are to be subjected to cell balancing. Memory 520 can also store various data, such as the State of Charge (SOC) and SOH data for each battery cell.

[0099] Multiple such memory 520s may be provided as needed. Memory 520 may be volatile memory or non-volatile memory. As volatile memory, RAM, DRAM, SRAM, etc., can be used for memory 520. As non-volatile memory, ROM, PROM, EAROM, EPROM, EEPROM, flash memory, etc., can be used for memory 520. The examples of memory 520 listed above are merely illustrative and are not limiting.

[0100] The Input / Output I / F 530 can provide an interface that connects input devices (not shown), such as keyboards, mice, and touch panels, with output devices (not shown), such as displays, and the MCU 510, enabling data transmission and reception.

[0101] The communication interface 540 is configured to send and receive various data with the server and may be various devices that support wired or wireless communication. For example, programs for calculating the State of Health (SOH) of battery cells and determining which cells are to be balanced, as well as various other data, can be sent and received from a separately provided external server via the communication interface 540. Thus, the battery management method according to one embodiment disclosed in this document can be recorded in the memory 520 and executed by the MCU 510.

[0102] The above description is merely illustrative of the technical concept disclosed in this document, and any person with ordinary skill in the art to which the embodiments disclosed in this document belong can make various modifications and variations without departing from the essential characteristics of the embodiments disclosed in this document.

[0103] Therefore, the embodiments disclosed herein are for illustrative purposes only, not to limit, the technical ideas disclosed herein, and such embodiments do not limit the scope of the technical ideas disclosed herein. The scope of protection for the technical ideas disclosed herein must be interpreted according to the claims described below, and all technical ideas within an equivalent scope should be interpreted as being included in the scope of rights of this document. [Explanation of symbols]

[0104] 1: Battery system 10: Battery pack 100: Multiple battery cells 110: First battery cell 120: Second battery cell 210: Information acquisition department 220: Controller

Claims

1. An information acquisition unit that measures the cell current of each of multiple battery cells, Based on the cell current, the usable capacity of each of the plurality of battery cells is calculated. A reference battery cell having the minimum usable capacity among the usable capacities of each of the aforementioned plurality of battery cells is extracted, and the minimum usable capacity is set as the reference capacity. Set a reference DOD, which is a DOD value set within an arbitrary DOD range. The first reference voltage corresponding to the reference DOD of the aforementioned reference battery cell is calculated, A controller that balances each of the plurality of battery cells based on the first reference voltage, A battery management device, including a battery management device.

2. The battery management device according to claim 1, wherein the controller adjusts the cell voltage of each of the plurality of battery cells so that the comparison voltage corresponding to the reference DOD of each of the plurality of battery cells corresponds to the first reference voltage.

3. The battery management device according to claim 1, wherein the controller sets the operating voltage range of each of the plurality of battery cells so that the operating capacity of each of the plurality of battery cells corresponds to the reference capacity.

4. The plurality of battery cells include a first battery cell and a second battery cell having a different usable capacity from the first battery cell. The battery management device according to claim 3, wherein the operating voltage range of the first battery cell is different from the operating voltage range of the second battery cell.

5. The usable capacity of the first battery cell is smaller than the usable capacity of the second battery cell. The battery management device according to claim 4, wherein the operating voltage range of the first battery cell includes the operating voltage range of the second battery cell.

6. The battery management device according to claim 3, wherein the controller sets a modified SOC for each of the plurality of battery cells based on the operating voltage range of each of the plurality of battery cells.

7. The battery management device according to claim 3, wherein the operating capacities corresponding to the operating voltage range of each of the plurality of battery cells are the same to one another.

8. The battery management device according to any one of claims 1 to 7, wherein the controller balances each of the plurality of battery cells when the difference between the maximum usable capacity and the minimum usable capacity of the plurality of battery cells is greater than or equal to a value that has already been set.

9. The battery management device according to any one of claims 1 to 7, wherein the standard DOD is defined as a state in which the DOD is 50% or half of the usable capacity of the battery cell.

10. The steps include calculating the usable capacity of each of the multiple battery cells, A reference battery cell having the minimum usable capacity among the usable capacities of each of the aforementioned plurality of battery cells is extracted, and the minimum usable capacity is set as the reference capacity. Set a reference DOD, which is a DOD value set within an arbitrary DOD range. A step of calculating a first reference voltage corresponding to the reference DOD of the reference battery cell, A step of balancing each of the plurality of battery cells based on the first reference voltage, Battery management methods, including those mentioned above.

11. Before performing the balancing step, The battery management method according to claim 10, further comprising the step of determining whether the difference between the maximum usable capacity and the minimum usable capacity of the plurality of battery cells is greater than or equal to a value that has already been set.

12. The step of performing the balancing described above is: The battery management method according to claim 10, further comprising the step of adjusting the cell voltage of each of the plurality of battery cells so that the comparison voltage corresponding to the reference DOD of each of the plurality of battery cells corresponds to the first reference voltage.

13. The step of performing the balancing described above is: The battery management method according to claim 12, further comprising the step of setting the operating voltage range of each of the plurality of battery cells so that the operating capacity of each of the plurality of battery cells corresponds to the reference capacity.

14. The step of performing the balancing described above is: The battery management method according to claim 13, comprising the step of setting a modified SOC for each of the plurality of battery cells based on the operating voltage range of each of the plurality of battery cells.

15. The plurality of battery cells include a first battery cell and a second battery cell having a different usable capacity from the first battery cell. The battery management method according to claim 12, wherein the operating voltage range of the first battery cell is different from the operating voltage range of the second battery cell.

16. The usable capacity of the first battery cell is smaller than the usable capacity of the second battery cell. The battery management method according to claim 15, wherein the operating voltage range of the first battery cell includes the operating voltage range of the second battery cell.

17. The battery management method according to claim 15, wherein the operating capacities corresponding to the operating voltage range of each of the plurality of battery cells are the same to one another.

18. The battery management method according to any one of claims 10 to 17, wherein the standard DOD is defined as a state in which the DOD is 50% or half of the usable capacity of the battery cell.

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