Battery overcharge prevention device and method thereof, and battery pack

Abstract

To provide a solution that prevents overcharging of a specific battery module caused by charging and discharging operations between a plurality of battery modules connected in parallel, thereby eliminating risks of fire.SOLUTION: The present disclosure relates to a battery overcharge prevention device and a method thereof, and a battery pack. The present disclosure provides a configuration that detects a target battery module containing an abnormal battery cell based on voltage changes in each battery cell in parallel-connected first to N-th battery modules, and prevents overcharging of the target battery module by bypassing a current drawn into the detected target battery module through a bypass circuit unit.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a technique for preventing overcharging of a battery. [Background technology]

[0002] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries that can be charged and discharged. Low-capacity secondary batteries are used in small, portable electronic devices such as smartphones, feature phones, laptops, digital cameras, and video cameras, while high-capacity secondary batteries are widely used as motor drive power sources and power storage batteries for hybrid vehicles and electric vehicles. Such secondary batteries include an electrode assembly consisting of a positive electrode and a negative electrode, a case to house the electrode assembly, and electrode terminals connected to the electrode assembly.

[0003] The above information disclosed in the background of the invention is intended to enhance understanding of the background of the invention only, and may therefore include information that does not constitute prior art. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a battery overcharge prevention device and method that can prevent overcharging of a specific battery module caused by charging / discharging operations between multiple battery modules connected in parallel, and a battery pack to which the function is applied.

[0005] However, the technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description of the invention. [Means for solving the problem]

[0006] According to one embodiment of the present invention for solving the above technical problems, the battery overcharge prevention device includes a bypass circuit unit for bypassing current drawn into each of first to Nth battery modules connected in parallel (N is a natural number of 2 or more), each battery module including a plurality of battery cells connected in series, and a processor configured to prevent overcharging caused by charging and discharging between the first to Nth battery modules, wherein the processor detects a target battery module having an abnormal battery cell based on a voltage change of each battery cell included in the first to Nth battery modules, and prevents overcharging of the target battery module by bypassing current drawn into the detected target battery module through the bypass circuit unit. [Effects of the Invention]

[0007] According to the present invention, an abnormal battery cell in which a short circuit has occurred and a target battery module including the abnormal battery cell are detected based on the voltage behavior of the battery cells, and a configuration is adopted in which a charging current drawn into the target battery module is bypassed through a bypass circuit composed of a switch element and a resistor element, thereby preventing overcharging of the target battery module and eliminating the risk of battery fire and explosion due to overcharging.

[0008] However, the effects obtained through the present invention are not limited to the above-mentioned effects, and other technical effects not mentioned herein will be clearly understood by those skilled in the art from the following description of the invention. [Brief explanation of the drawings]

[0009] The following drawings attached to this application illustrate preferred embodiments of the present invention and, together with the detailed description of the invention to be given later, serve to facilitate a better understanding of the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited to the matters depicted in these drawings.

[0010] [Figure 1] 1 illustrates a battery module according to an embodiment of the present invention. [Figure 2A] 1 illustrates a battery pack according to an embodiment of the present invention. [Figure 2B] 1 illustrates a battery pack according to an embodiment of the present invention. [Figure 3] 1 illustrates a parallel connection structure of battery modules according to an embodiment of the present invention. [Figure 4] 1 is a block diagram illustrating a battery overcharge prevention device according to an embodiment of the present invention. [Figure 5] 1 illustrates an example of a process for detecting an abnormal battery cell in a battery overcharge prevention device according to an embodiment of the present invention. [Figure 6] 1 illustrates an example of a process for detecting an abnormal battery cell in a battery overcharge prevention device according to an embodiment of the present invention. [Figure 7] 1 illustrates a first example of a process of bypassing a charging current through a bypass circuit unit in an apparatus for preventing overcharging of a battery according to an embodiment of the present invention. [Figure 8] 1 illustrates a first example of a process of bypassing a charging current through a bypass circuit unit in an apparatus for preventing overcharging of a battery according to an embodiment of the present invention. [Figure 9] 10 illustrates a second example of a process of bypassing a charging current through a bypass circuit unit in an apparatus for preventing overcharging of a battery according to an embodiment of the present invention. [Figure 10] 10 illustrates a second example of a process of bypassing a charging current through a bypass circuit unit in an apparatus for preventing overcharging of a battery according to an embodiment of the present invention. [Figure 11] 10 illustrates a second example of a process of bypassing a charging current through a bypass circuit unit in an apparatus for preventing overcharging of a battery according to an embodiment of the present invention. [Figure 12]10 illustrates a second example of a process of bypassing a charging current through a bypass circuit unit in an apparatus for preventing overcharging of a battery according to an embodiment of the present invention. [Figure 13] 1 illustrates a flowchart of a method for preventing battery overcharging according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Prior to this, the terms and phrases used in the specification and claims should not be construed as being limited to their ordinary or dictionary meanings. Instead, they should be interpreted as meanings and concepts consistent with the technical concept of the present invention, based on the principle that the inventor can appropriately define the concepts of terms to best describe his or her invention. Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely some of the most preferred embodiments of the present invention and do not fully represent the technical concept of the present invention. Therefore, it should be understood that various equivalents and modifications may exist as of the time of filing this application. Furthermore, as used in this specification, the words "comprise," "include," and / or "comprising," "including," specify the presence of a stated shape, number, step, operation, member, element, and / or group thereof, but do not exclude the presence or addition of one or more other shapes, numbers, operations, members, elements, and / or groups. Furthermore, when describing each embodiment of the present invention, the word "may" can include "one or more embodiments of the present invention."

[0012] In order to facilitate understanding of the invention, the accompanying drawings may not be drawn to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be used to refer to the same components in different embodiments.

[0013] A statement that two comparison objects are "identical" means that they are "substantially identical." Therefore, "substantially identical" can include cases where there is a deviation that is considered to be a low level in the art, for example, a deviation within 5%. Furthermore, uniformity of any parameter in a given region can mean uniformity on average.

[0014] Although terms such as "first" and "second" are used to describe various components, it is understood that these components are not limited by these terms. These terms are merely used to distinguish one component from another, and it is understood that a first component may also be a second component unless otherwise specified.

[0015] Throughout the specification, unless otherwise specified, each element may be singular or plural.

[0016] The fact that an arbitrary structure is disposed "on (or under)" a component or "above (or below)" a component can mean not only that the arbitrary structure is disposed in contact with the upper surface (or lower surface) of the component, but also that other structures may be interposed between the component and the arbitrary structure disposed above (or below) the component.

[0017] Furthermore, when it is stated that one component is "coupled," "coupled," or "connected" to another component, it should be understood that the components may be directly coupled or connected to each other, but it should also be understood that there may be other components "intervening" between the components, or that the components may be "coupled," "coupled," or "connected" via other components. Furthermore, when it is stated that one part is electrically coupled to another part, this includes not only the case where they are directly coupled, but also the case where they are coupled via another element in between.

[0018] Throughout the specification, "A and / or B" means A or B, or A and B, unless specifically stated to the contrary. That is, "and / or" includes all or any combination of the listed items. "C through D" means greater than or equal to C and less than or equal to D, unless specifically stated to the contrary.

[0019] 1. Battery structure In this embodiment, an "abnormal battery cell" is defined as a battery cell in which a short circuit occurs inside the cell or between the cell and an external low voltage terminal (e.g., GND) and a voltage drop occurs due to self-discharge, and a "target battery module" is defined as a battery module including an abnormal battery cell. In this embodiment, short ) exists in the target battery module (M target ) to prevent overcharging of the battery module by bypassing the charging current to the abnormal battery cell (C short As a premise for explaining a mechanism for preventing overcharging of a target battery cell caused by the above-mentioned phenomenon, the structures of a battery module and a battery pack will be described first. Meanwhile, the battery cells included in the battery module may be embodied in various structures and shapes such as cylindrical secondary battery cells, prismatic secondary battery cells, or coin-type secondary battery cells.

[0020] [Battery module] FIG. 1 is a perspective view showing a battery module M according to an embodiment of the present invention.

[0021] 1, a battery module M according to the present invention includes a plurality of battery cells C having electrodes 11 and 12 and arranged in one direction, a connection tab 20 connecting a battery cell 10a to an adjacent battery cell 10b, and a protection circuit module 30 having one end connected to the connection tab 20. The protection circuit module 30 may be a battery management system (hereinafter, referred to as BMS). The connection tab 20 includes a body portion 22 contacting the electrodes 11 and 12 between the adjacent battery cells 10a and 10b, and an extension portion extending from the body portion 22 and connected to the protection circuit module 30. The connection tab 20 may be a bus bar.

[0022] First, a battery cell C may include a battery case, an electrode assembly, and an electrolyte solution housed within the battery case. The electrode assembly and the electrolyte solution react electrochemically to generate energy. One side of the battery cell C may include terminals 11 and 12 electrically connected to a connection tab 20 and a vent 13 serving as a passage for discharging gas generated therein. The terminals 11 and 12 of the battery cell C may be a positive terminal 11 and a negative terminal 12 having opposite polarities, and the terminals 11 and 12 of adjacent battery cells 10a and 10b may be electrically connected in series or parallel via a connection tab 20 (described below). While the above description has been given using a series connection as an example, the present invention is not limited to this structure and various connection structures may be adopted as needed. In addition, the number and arrangement of the battery cells C are not limited to the structure shown in FIG. 1 and may be modified as needed.

[0023] A plurality of battery cells C may be arranged in one direction such that wide surfaces of the battery cells C face each other, and the arranged plurality of battery cells C may be fixed by housings 61, 62, 63, and 64. The housings 61, 62, 63, and 64 may include a pair of end plates 61 and 62 facing the wide surfaces of the battery cells C, and a side plate 63 and a bottom plate 64 connecting the pair of end plates 61 and 62. The side plate 63 may support the side surfaces of the battery cells C, and the bottom plate 64 may support the bottom surfaces of the battery cells C. In addition, the pair of end plates 61 and 62 may be connected to the side plate 63 and the bottom plate 64 by members such as bolts 65.

[0024] The protection circuit module 30 includes electronic components and a protection circuit, and may be electrically connected to the connection tab 20 (described later). The protection circuit module 30 includes a first protection circuit module 30a and a second protection circuit module 30b extending from different positions along the direction in which the plurality of battery cells C are arranged. The first protection circuit module 30a and the second protection circuit module 30b may be positioned parallel to each other but spaced apart by a predetermined distance, and electrically connected to the adjacent connection tab 20. For example, the first protection circuit module 30a may extend from one side of the plurality of battery cells C along the direction in which the plurality of battery cells C are arranged, and the second protection circuit module 30b may extend from the other side of the plurality of battery cells C along the direction in which the plurality of battery cells C are arranged. The second protection circuit module 30b may be positioned parallel to the first protection circuit module 30a but spaced apart by a predetermined distance across the vent 13. In this way, the two protection circuit modules are arranged side by side and spaced apart in the direction in which the plurality of battery cells C are arranged, thereby minimizing the area of ​​the PCB (Printed Circuit Board) that constitutes the protection circuit module. By configuring the protection circuit module as two separate protection circuit modules, unnecessary PCM area is minimized. The first protection circuit module 30a and the second protection circuit module 30b may be connected by a conductive connecting member 50. In this case, one side of the connecting member 50 is connected to the first protection circuit module 30a, and the other side is connected to the second protection circuit module 30b, thereby establishing an electrical connection between the two protection circuit modules.

[0025] The connection may be performed by any one of soldering, resistance welding, laser welding, and projection welding.

[0026] The connecting member 50 may be, for example, an electric wire. The connecting member 50 may also be made of an elastic or flexible material. The connecting member 50 may be used to check and manage whether the voltage, temperature, and current of the plurality of battery cells C are normal. That is, information on the voltage, current, temperature, etc. transmitted from the connecting tab adjacent to the first protection circuit module and information on the voltage, current, and temperature transmitted from the connecting tab adjacent to the second protection circuit module may be integrated and managed by the protection circuit module through the connecting member 50.

[0027] In addition, when the battery cell C swells, the elasticity or flexibility of the connecting member 50 absorbs the impact, thereby preventing damage to the first and second protection circuit modules 30a and 30b.

[0028] Furthermore, the shape and structure of the connecting member 50 are not limited to the shape shown in FIG.

[0029] As described above, since the protection circuit module 30 is provided with the first and second protection circuit modules 30a and 30b, the area of ​​the PCB constituting the protection circuit module can be minimized, thereby securing space inside the battery module M. This not only facilitates the fastening operation of connecting the connection tab 20 and the protection circuit module 30, but also makes it easier to repair the battery module M when an abnormality is detected, thereby improving work efficiency.

[0030] [Battery pack] 2A and 2B illustrate a battery pack P according to a preferred embodiment of the present invention.

[0031] The battery pack P may include a number of battery modules M and a housing H for accommodating the number of battery modules M. For example, the housing H may include first and second housings H1 and H2 coupled to each other in opposing directions with the number of battery modules M interposed therebetween. The number of battery modules M may be electrically connected using bus bars 51, and the number of battery modules M may be electrically connected to each other in a series / parallel or series-parallel mixed mode to obtain a required electrical output.

[0032] The above describes a typical battery structure in which battery cells C are connected in series or parallel to form a battery module M, and the battery modules M are connected in series or parallel to form a battery pack P. Among such battery wiring structures, this embodiment, as described below, assumes a structure in which a plurality of battery cells C are connected in series to form a battery module M, and a plurality of battery modules M are connected in parallel to form a battery pack P. The battery pack P of this embodiment includes first to Nth battery modules M1 to MN connected in parallel, and each battery module M1 to MN includes a plurality of battery cells C connected in series. FIG. 3 illustrates an example in which N battery modules M, each consisting of 10 battery cells C connected in series, are connected in parallel, and the battery cell voltage in a normal state is 4.1V and the battery module voltage is 41V. Based on this battery structure, the overcharge prevention mechanism of this embodiment will be described in detail below.

[0033] 2. Battery overcharge prevention device 4 is a block diagram illustrating a battery overcharge prevention device according to an embodiment of the present invention. Referring to FIG. 4, the battery overcharge prevention device of this embodiment may include a memory 100, a processor 200, a bypass circuit unit 300, and a communication module 400. The battery overcharge prevention device of FIG. 4 may constitute a battery pack P together with a plurality of battery modules M1 to MN.

[0034] The memory 100 may store at least one instruction to be executed by the processor 200, which will be described later. The memory 100 may be embodied in a volatile storage medium and / or a non-volatile storage medium, such as a read only memory (ROM) and / or a random access memory (RAM).

[0035] In addition, the memory 100 may store values ​​of a reference current range, a first reference voltage, a second reference voltage, an allowable error range, and a reference number of times in advance, and the respective values ​​stored in the memory 100 are detected by the processor 200 as described below to identify an abnormal battery cell (C short ) and abnormal battery cell (C short ) exists in the target battery module (M target Meanwhile, the respective values ​​of the reference current range, the first reference voltage, the second reference voltage, the tolerance range and the reference count stored in the memory 100 are determined based on the capacity of the battery module M and the battery pack P, the OCV (Open Circuit Voltage), the number of battery modules M connected in parallel (i.e., N), and the abnormal battery cell (C short ) may be predefined based on the resistance value of

[0036] The processor 200 controls the target battery module (M1 to MN) to detect the charge and discharge caused by the charge and discharge between the first to Nth battery modules M1 to MN. target ) and can be embodied as a central processing unit (CPU) or a system on chip (SoC), and can drive an operation system or application to control multiple hardware or software components connected to the processor 200 and perform various data processing and calculations. The processor 200 can be configured to execute at least one instruction stored in a memory 100 (described later) and store the execution result data in the memory 100.

[0037] Meanwhile, the processor 200 may be implemented in a BMS (Battery Management System) provided in the battery pack P or an MCU (Micro Controller Unit) within the BMS, and as is well known, may be configured to sense the current, voltage, and temperature at the battery cell C level, the current, voltage, and temperature at the battery module M level, and the current, voltage, and temperature at the battery pack P level. The sensing function of such a BMS is to detect an abnormal battery cell (C short ) and target battery module (M target ) detection process, the sensing operation of the current drawn from the battery pack P, the sensing operation of the current flow between the battery modules M, and the voltage sensing operation of the battery cells C can be supported.

[0038] The communication module 400 can establish a wired or wireless communication link between the processor 200 and a user terminal (e.g., a telematics terminal carried by a user or a dedicated terminal provided for implementing this embodiment), and can be embodied as a communication circuit that establishes, for example, a CAN (Controller Area Network) communication link, a LIN (Local Interconnect Network) communication link, or an Ethernet communication link between the processor 200 and the user terminal. The communication link established by the communication module 400 can be used to detect abnormal battery cells (C short ) can serve as a channel through which detected information is transmitted from the processor 200 to the user terminal.

[0039] The bypass circuit unit 300 may be configured to bypass the charging current drawn into each of the first to Nth battery modules M1 to MN connected in parallel with each other, and in particular, to bypass the charging current drawn into the abnormal battery cell (C short ) exists in the target battery module (M target ) by bypassing the charging current drawn by the target battery module (M target) can function as an EDS (Energy Drain System) that discharges the energy applied to the battery module (M). The bypass circuit unit 300 can include a plurality of sub-bypass circuits (310: 310_1, 310_2, 310_3), and each of the sub-bypass circuits (310: 310_1, 310_2, 310_3) can include a bypass switch 311 (e.g., a relay or FET) and a bypass resistor 312. target ) a node where charging current is drawn into the top battery cell, a bypass switch 311, a bypass resistor 312 and a discharge terminal P DCG The path connected to the target battery module (M target ) to bypass the charging current drawn into the bypass The bypass operation of the charging current through the bypass circuit unit 300 will be described in detail later.

[0040] 3. Abnormal battery cell detection 5 and 6 show an example of a process for detecting an abnormal battery cell in a battery overcharge prevention device according to an embodiment of the present invention.

[0041] As shown in FIG. 5, if an internal or external short circuit occurs in one or more of the battery cells C included in the first battery module M1, as shown in FIG. 6, charging and discharging will occur between the first and second battery modules M1 and M2 connected in parallel even if charging and discharging of the battery pack P is not performed (the numerical values ​​in FIGS. 5 and 6 are examples to help understand the embodiments).

[0042] Specifically, the abnormal battery cell (C short ), the cell voltage will decrease due to self-discharge, and therefore the abnormal battery cell (C shortA voltage difference is formed between the module voltage of the first battery module M1 including the abnormal battery cell (C short ) continuously decreases, but the normal battery cells of the first battery module M1 are continuously charged by the charging current drawn from the second battery module M2 to the first battery module M1, causing their voltage to continuously increase, resulting in overcharging.

[0043] The abnormal battery cell (C short ) to prevent overcharging of normal battery cells due to the occurrence of abnormal battery cells (C short ), and abnormal battery cells (C short ) exists in the target battery module (M target ), which will be specifically described below.

[0044] As mentioned above, the abnormal battery cell (C short ) occurred in the target battery module (M target ), abnormal battery cell (C short Since the voltage change patterns of the normal battery cells are different, the processor 200 determines whether the abnormal battery cell (C short ), and abnormal battery cells (C short ) exists in the target battery module (M target ) can be detected.

[0045] In this case, the processor 200 detects the abnormal battery cell (C short ) and target battery module (M target) detection operation can be started. For example, if the load is a motor, when the motor is driven by the battery pack P, discharge and regenerative charging occur frequently, causing voltage fluctuations in the battery pack P, battery module M, and battery cells C. short ) occurs due to the occurrence of "abnormal battery cell (C short ) and the different voltage change patterns of normal battery cells cannot be accurately grasped.

[0046] That is, the abnormal battery cell (C short ) and target battery module (M target The detection operation of the abnormal battery cell (C) must be performed under the condition that charging and discharging is performed between the battery modules M, which means that charging and discharging at the battery pack P level must be performed under the condition that charging and discharging is not performed. Therefore, the processor 200 detects the abnormal battery cell (C) only when the load is not driven. short ) and target battery module (M target The processor 200 can determine whether the load is in an undriven state based on the magnitude of the current drawn from the battery pack P. For example, if the magnitude of the current drawn from the battery pack P is within a reference current range (e.g., between -1 A and 1 A) stored in the memory 100, the processor 200 determines that the load is in an undriven state and detects an abnormal battery cell (C short ) and target battery module (M target ) detection operation can be started.

[0047] Meanwhile, when no charging or discharging is performed between the first to Nth battery modules M1 to MN, the abnormal battery cell (C short ) and target battery module (M target In order to eliminate the inefficiency of the detection operation, the processor 200 detects the abnormal battery cell (C) only when a current flows between the first to Nth battery modules M1 to MN (i.e., only when the first to Nth battery modules M1 to MN are charged or discharged). short) and target battery module (M target ) detection operation.

[0048] Abnormal battery cell (C short ) and target battery module (M target When the detection operation is started, the processor 200 determines whether there are any battery cells C whose voltage increases and any battery cells C whose voltage decreases among the plurality of battery cells C included in any one battery module M. target ) can be detected.

[0049] Specifically, the processor 200 determines whether or not a first condition exists that a battery cell C whose voltage increases to or exceeds a predetermined first reference voltage and a second condition exists that a battery cell C whose voltage decreases to or falls below a predetermined second reference voltage, based on the Mth battery module (M target ) can be detected (the first reference voltage has a value greater than the second reference voltage). A battery cell C that satisfies the first condition corresponds to a normal battery cell, and a battery cell C that satisfies the second condition corresponds to an abnormal battery cell (C short ) and such normal battery cells and abnormal battery cells (C short ) is the battery module M that includes all of the battery modules (M target ) can be detected.

[0050] Abnormal battery cell (C short ) and target battery module (M target In order to improve the detection accuracy of the battery module (M th battery module in the above example), when the first and second conditions are satisfied and the voltage change amount per unit time of each of the plurality of battery cells C that satisfy the first condition is within a predetermined tolerance range, the processor 200 classifies the corresponding battery module (M th battery module in the above example) as the target battery module (M targetThat is, even if a plurality of battery cells C included in the Mth battery module satisfy the first condition and are detected as normal battery cells, if the manner of voltage increase up to the first reference voltage differs for each battery cell that satisfies the first condition, the cause of the voltage increase may be determined as an abnormal battery cell (C short ) cannot be identified as a charge / discharge between the battery module M, but an abnormal battery cell (C short When charging and discharging between the battery modules M according to the first condition, the voltage increase patterns of the normal battery cells up to the first reference voltage will be similar. Therefore, the processor 200 determines the similarity of the voltage increase patterns of the respective battery cells C that satisfy the first condition and determines the abnormal battery cell (C short ) and target battery module (M target The amount of voltage change per unit time (i.e., the rate of voltage increase per unit time) may be used as a quantitative criterion for determining the similarity of the voltage increase pattern, and accordingly, only when the amount of voltage change per unit time of each of the plurality of battery cells C that satisfy the first condition is within a predetermined allowable error range, the corresponding battery module M is determined to be a target battery module (M target ) can be detected.

[0051] Abnormal battery cell (C short ) and target battery module (M target As an additional means for improving the detection accuracy of the battery module M, the battery module M is determined to be the target battery module (M) only when the situation where the first and second conditions are satisfied is repeated more than a predetermined reference number of times. target ) may be detected.

[0052] Through the above process, abnormal battery cells (C short ) and target battery module (M target ) is detected, the processor 200 short) occurs to the user terminal through the communication module 400, so that the user can stop using the battery pack P and perform maintenance on it.

[0053] 4. Overcharge prevention mechanism Abnormal battery cell (C short ) and target battery module (M target ) is detected, the processor 200 selects the target battery module (M target ) to prevent overcharging of normal battery cells due to the charging current drawn into the target battery module (M target ) can be bypassed through the bypass circuit unit 300. Two embodiments of the overcharge prevention mechanism can be presented, and each embodiment will be described in detail below.

[0054] (1) First Example of Overcharge Prevention Mechanism 7 and 8 are diagrams illustrating a first embodiment of the overcharge prevention mechanism. Referring to FIGS. 7 and 8, the bypass circuit unit 300 of the first embodiment includes a plurality of sub-bypass circuits (310: 310_1, 310_2, 310_3), and each of the sub-bypass circuits (310: 310_1, 310_2, 310_3) may include a bypass switch 311 and a bypass resistor 312 connected in series. The bypass circuit unit 300 of the first embodiment may be provided inside the battery pack P or may be provided in a host device (e.g., a vehicle) to which the battery pack P is applied.

[0055] Referring to FIG. 7, a plurality of sub-bypass circuits 310: 310_1, 310_2, 310_3 are connected in parallel to the first to Nth battery modules M1 to MN, respectively, and form a bypass path P bypass ) can be formed.

[0056] Taking the Mth battery module as an example (M is a natural number equal to or less than N), the bypass path (P bypass ) is the current draw node N for the top battery cell of the Mth battery module IN , the bypass switch 311, the bypass resistor 312 and the discharge terminal P DCG The discharge terminal P DCG The sub-bypass circuits 310, 310_1, 310_2, 310_3 may be implemented as a terminal capable of draining the bypassed charging current, such as a ground terminal. The sub-bypass circuits 310, 310_1, 310_2, 310_3 may be provided for each of the first to Nth battery modules M1 to MN. Therefore, each of the battery modules M1 to MN may be provided with a faulty battery cell (C short ) is generated, bypassing the charging current drawn in due to the bypass ) may be provided.

[0057] Based on the above-described wiring structure of the bypass circuit unit 300, the processor 200 short ) and target battery module (M target ) (in the example of FIG. 8, the first battery module M1) is detected (which battery module M among the plurality of battery modules M1 to MN has an abnormal battery cell (C short ) occurred in the target battery module (M target ) is determined by the basic functions supported by the BMS), the target battery module (M target ) can be closed, and accordingly, the bypass switch 311 of the sub-bypass circuit connected to the target battery module (M target ) is drawn into the bypass path (P bypass )

[0058] (2) Second Example of Overcharge Prevention Mechanism 9 to 12 are exemplary diagrams illustrating a second embodiment of the overcharge prevention mechanism. Referring to FIGS. 9 to 12, the bypass circuit unit 300 of the second embodiment includes a plurality of sub-bypass circuits (310: 310_1, 310_2, 310_3), and each of the sub-bypass circuits (310: 310_1, 310_2, 310_3) may include a series-connected wiring changeover switch 313, a bypass switch 311, and a bypass resistor 312. The bypass circuit unit 300 of the second embodiment may be provided inside the battery pack P. The bypass switch 311 of the second embodiment may have a normally open structure.

[0059] The bypass circuit unit 300 may include first to Kth sub-bypass circuits. When K is quantitatively expressed with respect to N representing the number of battery modules M, K may be expressed as a natural number corresponding to floor(N / 2) (floor is a lowering operator). For example, if five battery modules M are connected in parallel (i.e., N=5), K may correspond to 2, and if six battery modules M are connected in parallel (i.e., N=6), K may correspond to 3.

[0060] In addition, when L is defined as a natural number equal to or less than K, the L-th sub-bypass circuit is a shared bypass path (P bypass ) can be constructed.

[0061] 9 illustrates an example in which N is 6 and K is 3, and six battery modules M and three sub-bypass circuits 310_1, 310_2, and 310_3 are provided. The first sub-bypass circuit 310_1 is connected between the first battery module M1 and the second battery module M2 and can form a shared bypass path for bypassing the charging currents drawn into the first battery module M1 and the second battery module M2. The second sub-bypass circuit 310_2 is connected between the third battery module M3 and the fourth battery module M4 and can form a shared bypass path for bypassing the charging currents drawn into the third battery module M3 and the fourth battery module M4. The third sub-bypass circuit 310_3 is connected between the fifth battery module M5 and the sixth battery module M6 and can form a shared bypass path for bypassing the charging currents drawn into the fifth battery module M5 and the sixth battery module M6.

[0062] That is, unlike the first embodiment in which each of the battery modules M1 to MN is provided with a sub-bypass circuit, in the second embodiment, two battery modules M share one sub-bypass circuit, and the abnormal battery cell (C short ) occurs in the battery module M. bypass ) can be formed.

[0063] The wiring structure and operation of the sub-bypass circuit will be described in detail with reference to FIG. 10, which illustrates the first and second battery modules M1, M2 and the first sub-bypass circuit 310_1 (it should be made clear that the first and second battery modules M1, M2 referred to here refer to two battery modules M adjacent to each other and connected in parallel among the first to Nth battery modules M1 to MN, and do not refer to the two battery modules M at the ends of the parallel connection structure).

[0064] The connection changeover switch 313 may have first to third nodes N1 to N3. Here, the first node N1 may be connected to a current drawing node for the uppermost battery cell of the first battery module M1, the second node N2 may be connected to a current drawing node for the uppermost battery cell of the second battery module M2, and the third node N3 may be connected to the bypass switch 311. The connection changeover switch 313 is configured to selectively connect the first and second nodes N1 and N2 to the third node N3 under the control of the processor 200. The connection changeover switch 313 may be embodied as a relay including a relay coil (not shown) and a switch element that performs contact switching by excitation of the relay coil. The wiring changeover switch 313 may be configured to have a normally closed structure (NC: Normally Close) between the first and third nodes N1, N3 and a normally open structure (NO: Normally Open) between the second and third nodes N2, N3, or to have a normally closed structure between the second and third nodes N2, N3 and a normally open structure between the first and third nodes N1, N3. To facilitate understanding of the embodiments, the following description will be given assuming that the wiring changeover switch 313 has a normally closed structure between the first and third nodes N1, N3 and a normally open structure between the second and third nodes N2, N3.

[0065] In the wiring structure of FIG. 10, the bypass path (P bypass ) is connected to the first node N1 (i.e., the current sink node for the top battery cell of the first battery module M1), the bypass switch 311, the bypass resistor 312 and the discharge terminal P DCG and a bypass path (P bypass ) is connected to the second node N2 (i.e., the current sink node for the top battery cell of the second battery module M2), the bypass switch 311, the bypass resistor 312 and the discharge terminal P DCGAccordingly, the wiring changeover switch 313, the bypass switch 311, and the bypass resistor 312 may form a shared bypass path for bypassing the charging currents respectively drawn into the first and second battery modules M1 and M2 that are adjacently connected in parallel to each other.

[0066] Based on the above-described wiring structure of the bypass circuit unit 300, the processor 200 determines whether the first battery module M1 is a target battery module (M target ), the third node N3 is connected to the first node N1, and the bypass switch 311 is closed, so that the charging current drawn into the first battery module M1 is diverted to the bypass path (P bypass When the wiring changeover switch 313 has a normally closed structure between the first and third nodes N1 and N3 and a normally open structure between the second and third nodes N2 and N3, the bypass path (P bypass ) can be formed only through the closing operation of the bypass switch 311. Accordingly, as shown in FIG. 11, the charging current drawn into the first battery module M1 passes through the bypass path (P bypass )

[0067] If the second battery module M2 is the target battery module (M target ), the processor 200 connects the third node N3 to the second node N2 and closes the bypass switch 311 to direct the charging current drawn into the second battery module M2 through the bypass path (P bypass ) can be bypassed. Accordingly, as shown in FIG. 12, the charging current drawn into the second battery module M2 can be bypassed through the bypass path (P bypass )

[0068] 5. How to prevent battery overcharging 13 is a flowchart of a method for preventing battery overcharging according to an embodiment of the present invention. The method for preventing battery overcharging according to this embodiment will be described with reference to FIG. 13. Detailed descriptions of components that overlap with those described above will be omitted, and the description will focus on the chronological configuration.

[0069] First, the processor 200 determines whether a battery cell (C short ) exists in the target battery module (M target ) is detected (S10). Step S10 may be performed when the current drawn from the battery pack P is within a preset reference current range and / or when current flows between the first to Nth battery modules M1 to MN.

[0070] In step S10, the processor 200 determines whether there are any battery cells C whose voltage increases and any battery cells C whose voltage decreases for a target battery module (M) by determining whether there are any battery cells C whose voltage increases and any battery cells C whose voltage decreases for a target battery module (M) target Specifically, the processor 200 determines whether or not a first condition exists that a battery cell C whose voltage increases to or exceeds a predetermined first reference voltage, and a second condition exists that a battery cell C whose voltage decreases to or falls below a predetermined second reference voltage, based on the Mth battery module. target ) can be detected (M is a natural number less than or equal to N).

[0071] In this case, if the first and second conditions are satisfied and the voltage change amount per unit time of each of the plurality of battery cells C that satisfy the first condition is within a predetermined tolerance range, the processor 200 determines the Mth battery module as the target battery module (M targetAdditionally, if the situation where the first and second conditions are satisfied is repeated for a predetermined number of times or more, the processor 200 may detect the Mth battery module as a target battery module (M target ) can be detected.

[0072] Subsequently, the processor 200 detects the target battery module (M target ) from other battery modules M connected in parallel to the target battery module (M target ) caused by the charging current drawn into the target battery module (M target ) is prevented from being overcharged by using the bypass circuit unit 300. target ) is bypassed (S20).

[0073] When the above-mentioned "first embodiment of the overcharge prevention mechanism" is applied, in step S20, the processor 200 target ) is connected to the target battery module (M target ) to direct the charging current drawn into the bypass path (P bypass ) can be bypassed.

[0074] When the above-described "Second embodiment of the overcharge prevention mechanism" is applied, in step S20, the processor 200 i) determines whether the first battery module M1 is a target battery module (M target ), the third node N3 is connected to the first node N1, and the bypass switch 311 is closed, so that the charging current drawn into the first battery module M1 is diverted to the bypass path (P bypass ii) the second battery module M2 bypasses the target battery module (M target ), the third node N3 is connected to the second node N2, and the bypass switch 311 is closed, so that the charging current drawn into the second battery module M2 is diverted to the bypass path (Pbypass ) can be bypassed.

[0075] In this way, according to the present invention, an abnormal battery cell in which a short circuit has occurred and a target battery module including the abnormal battery cell are detected based on the voltage behavior of the battery cells, and a configuration is adopted in which a charging current drawn into the target battery module is bypassed through a bypass circuit composed of a switch element and a resistor element, thereby preventing overcharging of the target battery module and eliminating the risk of battery fire and explosion due to overcharging.

[0076] The implementations described herein may be embodied as, for example, a method or process, an apparatus, a software program, a data stream, or a signal. Even if discussed only in the context of a single form of implementation (e.g., discussed only as a method), the discussed implementation of a feature may also be embodied in other forms (e.g., an apparatus or a program). An apparatus may be embodied in appropriate hardware, software, firmware, etc. A method may be embodied in an apparatus, such as, for example, a processor, which generally refers to a processing device including, for example, a computer, a microprocessor, an integrated circuit, or a programmable logic device. Processors also include communication devices, such as computers, mobile phones, portable / personal digital assistants (“PDAs”), and other devices that facilitate communication of information between end users.

[0077] Although the present invention has been described with reference to the embodiments shown in the drawings, it is understood that these are merely illustrative and that those skilled in the art will recognize that various modifications and equivalent alternative embodiments are possible. Therefore, the technical scope of the present invention should be determined by the following claims. [Explanation of symbols]

[0078] 100:Memory 200: Processor 300: Bypass circuit section 400: Communication module

Claims

1. a bypass circuit unit for bypassing current drawn into each of the first to Nth battery modules connected in parallel (N is a natural number of 2 or more), each battery module including a plurality of battery cells connected in series; a processor configured to prevent overcharging caused by charging and discharging between the first to Nth battery modules; The processor: a target battery module having an abnormal battery cell detected based on a voltage change of each battery cell included in the first to Nth battery modules, and preventing overcharging of the target battery module by bypassing a current drawn into the detected target battery module through the bypass circuit unit.

2. the first to Nth battery modules constitute a battery pack; 2. The device for preventing battery overcharge according to claim 1, wherein the processor starts an operation of detecting the abnormal battery cell and the target battery module when a current drawn from the battery pack is within a preset reference current range.

3. 2. The device for preventing battery overcharge of claim 1, wherein the processor starts a detection operation of the abnormal battery cell and the target battery module when a current flow occurs between the first to Nth battery modules.

4. 2. The device for preventing battery overcharge according to claim 1, wherein the processor detects the target battery module by determining whether there are battery cells whose voltages increase and battery cells whose voltages decrease among a plurality of battery cells included in any one battery module.

5. 5. The battery overcharge prevention device according to claim 4, wherein the processor detects the target battery module by determining whether or not i) a first condition that a battery cell whose voltage increases to or exceeds a predetermined first reference voltage exists, and ii) a second condition that a battery cell whose voltage decreases to or below a predetermined second reference voltage exists, based on an Mth battery module (M is a natural number equal to or less than N).

6. 6. The device for preventing battery overcharge according to claim 5, wherein the processor detects the M battery module as the target battery module when the first and second conditions are met and an amount of voltage change per unit time of each of the plurality of battery cells that satisfy the first condition is within a predetermined allowable error range.

7. 6. The device for preventing battery overcharge according to claim 5, wherein the processor detects the M battery module as the target battery module when a situation in which the first and second conditions are satisfied is repeated a predetermined number of times or more.

8. the bypass circuit unit includes a plurality of sub-bypass circuits, 2. The battery overcharge protection device according to claim 1, wherein each sub-bypass circuit includes a bypass switch and a bypass resistor connected in series.

9. the plurality of sub-bypass circuits are connected in parallel to the first to Nth battery modules, respectively, to form bypass paths for bypassing charging currents drawn into the corresponding battery modules; 9. The device for preventing overcharge of a battery according to claim 8, wherein the bypass path comprises a path connected to a current sink node for a top battery cell of the corresponding battery module, the bypass switch, the bypass resistor, and a discharge terminal.

10. 10. The device for preventing battery overcharge according to claim 9, wherein the processor closes the bypass switch of the sub-bypass circuit connected to the target battery module to bypass the charging current drawn into the target battery module through the bypass path.

11. the bypass circuit unit includes a sub-bypass circuit, 2. The battery overcharge protection device according to claim 1, wherein each sub-bypass circuit includes a series-connected wiring changeover switch, a bypass switch, and a bypass resistor.

12. 12. The device for preventing overcharge of a battery according to claim 11, wherein the connection changeover switch, the bypass switch, and the bypass resistor form a shared bypass path for bypassing charging currents respectively drawn into first and second battery modules adjacent to each other and connected in parallel.

13. The connection changeover switch includes first to third nodes and is configured to selectively connect the first and second nodes to the third node, 13. The device for preventing battery overcharge of claim 12, wherein the first node is connected to a current drawing node for a top battery cell of the first battery module, the second node is connected to a current drawing node for a top battery cell of the second battery module, and the third node is connected to the bypass switch.

14. the bypass path of the first battery module comprises a path connected to the first node, the bypass switch, the bypass resistor, and a discharge terminal; 14. The device for preventing overcharge of a battery according to claim 13, wherein the bypass path of the second battery module comprises a path connected to the second node, the bypass switch, the bypass resistor, and a discharge terminal.

15. The processor: If the first battery module is detected as the target battery module, connecting the third node to the first node and closing the bypass switch to bypass the charging current drawn into the first battery module through the bypass path; 15. The device for preventing battery overcharge of claim 14, wherein, when the second battery module is detected as the target battery module, the third node is connected to the second node and the bypass switch is closed, thereby bypassing the charging current drawn into the second battery module through the bypass path.

16. The bypass circuit unit includes first to K-th sub-bypass circuits (K is a natural number corresponding to floor(N / 2), and floor is a lowering operator); The battery overcharge protection device according to claim 13, wherein the L-th sub-bypass circuit forms a shared bypass path for bypassing charging currents drawn into the 2L-1 battery module and the 2L battery module, respectively (L is a natural number equal to or less than K).

17. a step of detecting a target battery module in which an abnormal battery cell exists based on a voltage change of each battery cell included in first to Nth battery modules connected in parallel, each battery module including a plurality of battery cells connected in series; and bypassing the current drawn into the detected target battery module so as to prevent overcharging of the target battery module caused by charging current drawn into the target battery module from other battery modules connected in parallel to the target battery module.

18. In the detecting step, the processor 18. The method of claim 17, wherein the target battery module is detected by determining whether or not there are battery cells whose voltages increase and battery cells whose voltages decrease among a plurality of battery cells included in any one battery module.

19. In the bypassing step, the processor 18. The method of claim 17, wherein the current drawn into the target battery module is bypassed using a bypass circuit unit configured to bypass the current drawn into each of the first to Nth battery modules.

20. First to Nth battery modules (N is a natural number of 2 or more) connected in parallel, each battery module including a plurality of battery cells connected in series; a BMS (Battery Management System) configured to prevent overcharging caused by charging and discharging between the first to Nth battery modules; the BMS detects a target battery module having an abnormal battery cell based on a voltage change of each battery cell included in the first to Nth battery modules, and prevents overcharging of the target battery module by bypassing a current drawn into the detected target battery module.

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