KR102580396B1 - Battery management system with resistance detection function and resistance detection method between battery cells - Google Patents

Abstract

A battery management system with a resistance detection function according to a preferred embodiment of the present invention includes a battery array unit including a plurality of battery cells connected in series with each other and a plurality of switch modules provided between the battery cells, the plurality of battery cells. a battery manager forming a bypass circuit that bypasses the at least two selected battery cells to exclude a diagnostic node between the at least two battery cells selected from among the at least two battery cells, and a diagnostic current flowing in the bypass circuit, and the battery in which the bypass circuit is formed. It includes a main control unit that calculates the diagnostic resistance of the diagnostic node using the diagnostic voltage of the array unit.

Description

Battery management system with resistance detection function, and method for detecting resistance between battery cells {BATTERY MANAGEMENT SYSTEM WITH RESISTANCE DETECTION FUNCTION AND RESISTANCE DETECTION METHOD BETWEEN BATTERY CELLS}

The present invention relates to a battery management system with a resistance detection function and a method for detecting resistance between battery cells.

In general, electric vehicles can drive on the road by supplying electric energy from a battery to an electric motor to generate driving force, and rotating wheels through the generated driving force.

The battery of an electric vehicle is classified as a very important component, with its cost accounting for close to half of the entire electric vehicle. Additionally, since the battery of an electric vehicle is required to move the electric vehicle, it is desirable to be a high-voltage battery that outputs high voltage and high current.

A type of battery for these electric vehicles is a lithium-ion battery. Lithium-ion batteries have a basic voltage of 3.75V and can have a charging voltage of 4.2V when fully charged.

The battery of an electric vehicle using a lithium-ion battery may include a plurality of battery cells connected in series to enable high voltage output, and a battery pack that accommodates the plurality of battery cells.

Since the battery of such an electric vehicle flows a very large current, if the connection between the plurality of battery cells is poor or deterioration occurs, the resistance between the plurality of battery cells increases. This increase in resistance has been pointed out as a cause of dangerous situations such as explosion of the battery of an electric vehicle or occurrence of a fire, and a method for detecting this is required.

Republic of Korea Patent No. 10-1628858

Accordingly, the present invention was developed in consideration of the above circumstances. A bypass circuit excluding the battery cells to be diagnosed is created to measure the diagnostic current, and when the diagnostic current changes beyond a certain level, a resistance component occurs between the battery cells to be diagnosed. The purpose of the present invention is to provide a battery management system with a resistance detection function that determines the resistance of the battery cells, and a method for detecting resistance between battery cells.

A battery management system with a resistance detection function according to a preferred embodiment of the present invention for achieving the above object includes a battery array unit including a plurality of battery cells connected in series with each other and a plurality of switch modules provided between the battery cells. ; a battery management unit that forms a bypass circuit that bypasses the at least two selected battery cells to exclude a diagnostic node between the at least two selected battery cells among the plurality of battery cells; and a main control unit that calculates the diagnostic resistance of the diagnostic node using the diagnostic current flowing in the bypass circuit and the diagnostic voltage of the battery array unit where the bypass circuit is formed.

Each of the plurality of switch modules may be composed of a combination of at least three N-channel MOSFETs.

Each of the plurality of switch modules may be composed of a combination of at least three transmissions.

Each of the plurality of switch modules includes: a first node connected to a positive voltage terminal or a negative voltage terminal of at least one battery cell among the plurality of battery cells; a second node connected to or disconnected from the first node by at least one switch element; and a third node connected to the first node, connected to the second node, or disconnected from the first node and the second node by at least two switch elements.

When the first node and the third node in the plurality of switch modules are connected, or the second node and the third node are connected, the bypass circuit may be formed.

The battery management unit includes a switch control unit that controls at least two switch modules provided on one side and the other side of each of the at least two selected battery cells; a balancing unit measuring the diagnostic voltage of the plurality of battery cells excluding the at least two selected battery cells; and a current measuring unit that measures the diagnostic current flowing in the bypass circuit.

The main control unit may compare the diagnostic resistance with a preset reference resistance and determine whether a resistance component has occurred in the diagnostic node according to the comparison result.

When the main control unit determines that diagnosis of a node between the plurality of battery cells is necessary, the main control unit may select at least one diagnostic node and transmit the selection result to the switch control unit.

A method of detecting resistance between battery cells according to a preferred embodiment of the present invention for achieving the above object includes a battery array unit including a plurality of battery cells connected in series with each other and a plurality of switch modules provided between the battery cells. A method for detecting resistance between battery cells of an electric vehicle, comprising forming a bypass circuit that bypasses the at least two selected battery cells to exclude a diagnostic node between the at least two battery cells preselected among the plurality of battery cells. circuit forming step; A current measurement step of measuring diagnostic current flowing in the bypass circuit; A voltage measurement step of measuring a diagnostic voltage of the battery array unit where the bypass circuit is formed; and a diagnostic resistance calculation step of calculating the diagnostic resistance of the diagnostic node using the diagnostic current and the diagnostic voltage.

Before the bypass circuit forming step, the method may further include a diagnostic node selection step of selecting the diagnostic node between at least two battery cells among the plurality of battery cells.

The bypass circuit forming step controls switching of a first switch module provided at one positive voltage terminal of the at least two selected battery cells, and a second switch module provided at the other negative voltage terminal of the at least two battery cells. The bypass circuit can be formed by connecting the first switch module and the second switch module through switching control.

It may further include a resistance comparison step of comparing the diagnostic resistance with a preset reference resistance.

An abnormality determination step of determining that a resistance component has occurred in the diagnostic node when the diagnostic resistance is greater than the reference resistance; and a normal determination step of determining that the diagnostic node is in a normal state when the diagnostic resistance is less than the reference resistance.

According to a battery management system with a resistance detection function and a method for detecting resistance between battery cells according to a preferred embodiment of the present invention, a bypass circuit is created excluding the battery cell to be diagnosed, the diagnostic current is measured, and the diagnostic current is kept constant. If there is an abnormal change, it can be determined that a resistance component has occurred between the battery cells to be diagnosed.

In addition, by diagnosing whether a resistance component of a diagnostic node between battery cells occurs, it is effective to prevent heat generation and fire phenomenon caused by resistance components between battery cells.

1 is a block diagram of a battery management system with a resistance detection function according to a preferred embodiment of the present invention.
FIG. 2 is a detailed block diagram of the battery management unit of FIG. 1.
FIG. 3 is a diagram for explaining the detailed structure of the switch module of FIG. 1.
Figure 4 is a diagram showing an example of a bypass path that bypasses a battery cell to be diagnosed.
Figure 5 is a diagram showing another example of a bypass path that bypasses at least two battery cells to be diagnosed.
Figure 6 is a diagram showing another example of a bypass path that bypasses at least two battery cells to be diagnosed.
Figure 7 is a flowchart of a method for detecting resistance between battery cells according to a preferred embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. First, when adding reference signs to components in each drawing, it should be noted that the same components are given the same reference numerals as much as possible even if they are shown in different drawings. In addition, preferred embodiments of the present invention will be described below, but the technical idea of the present invention is not limited or restricted thereto, and of course, it can be modified and implemented in various ways by those skilled in the art.

1 is a block diagram of a battery management system with a resistance detection function according to a preferred embodiment of the present invention. FIG. 2 is a detailed block diagram of the battery management unit of FIG. 1.

Referring to FIGS. 1 and 2, the battery management system 100 with a resistance detection function according to a preferred embodiment of the present invention detects the battery cells around the node when it is intended to diagnose a node between battery cells. By forming a bypass circuit excluding, the diagnostic current of the bypass circuit is measured, and if the diagnostic current changes more than a certain level, it is determined that a resistance component has occurred in the node between the battery cells to be diagnosed.

The battery management system 100 with a resistance detection function may include a battery array unit 110, a battery management unit 120, and a main control unit 130.

The battery array unit 110 may include a plurality of battery cells (Cell1 to Cell(m)) connected in series with each other and a plurality of switch modules (SW1 and SW2) provided between each battery cell.

A plurality of battery cells (Cell1 to Cell(m)) can output high voltage to the load (LOAD). When a plurality of battery cells (Cell1 to Cell(m)) are poorly connected to each other, a resistance component may be generated. If a resistance component occurs at the connection node of a plurality of battery cells (Cell1 to Cell(m)), a dangerous situation such as a fire may occur due to the resistance component. To detect such resistance components, a switch module may be provided between each of the plurality of battery cells (Cell1 to Cell(m)).

The plurality of switch modules (SW1, SW2) may connect or disconnect the plurality of battery cells (Cell1 to Cell(m)). A plurality of switch modules (SW1, SW2) may be connected to each other with at least two battery cells interposed therebetween. At this time, a bypass circuit (DT) that bypasses at least two battery cells may be formed. The detailed structure of the plurality of switch modules (SW1 and SW2) will be described later with reference to FIG. 4.

The battery management unit 120 may perform voltage balancing of a plurality of battery cells (Cell1 to Cell(m)). The battery management unit 120 may control a plurality of switch modules (SW1, SW2) to diagnose nodes between a plurality of battery cells (Cell1 to Cell(m)).

The battery management unit 120 may include a switch control unit 121, a balancing unit 123, and a current measurement unit 125. The battery management unit 120 includes a plurality of flip-flops (F/F) that maintain and store signals of various nodes (Nd1, Nd2, Nd3) of a plurality of switch modules (SW1, SW2), and a plurality of switch modules (SW1, SW2). A first mux (MUX1) that selects and outputs one signal among the signals of various nodes (Nd1, Nd2, Nd3), and among the signals of the third nodes (Nd3, Ndc) of the plurality of switch modules (SW1, SW2) A second mux (MUX2) that selects and outputs one signal, and a demux that outputs the output signal of the second mux (MUX2) to the balancing unit 123 and the current measurement unit 125 through a plurality of output terminals. (DEMUX) may be further included.

The switch control unit 121 may control the plurality of switch modules (SW1, SW2) to adjust the connection relationship of the plurality of battery cells (Cell1 to Cell(m)). The switch control unit 121 includes at least two switch modules (SW1, SW2) can be controlled. In one embodiment, the switch control unit 121 may receive signals from the first node (Nd1), the second node (Nd2), and the third node (Nd3) of the first switch module (SW1). The switch control unit 121 may determine the current state of the first switch module (SW1) through signals from the first node (Nd1), the second node (Nd2), and the third node (Nd3). Additionally, the switch control unit 121 may receive signals from the first node (Nda), the second node (Ndb), and the third node (Ndc) of the second switch module (SW2). The switch control unit 121 may determine the current state of the second switch module (SW2) through signals of the first node (Nda), the second node (Ndb), and the third node (Ndc). The switch control unit 121 generates a gate control signal in consideration of the current state of each of the plurality of switch modules (SW1, SW2), and transmits the generated gate control signal to each of the plurality of switch modules (SW1, SW2), thereby The switching operation of each switch module (SW1, SW2) can be controlled.

The balancing unit 123 may perform voltage balancing of a plurality of battery cells (Cell1 to Cell(m)). The balancing unit 123 may measure the diagnostic voltage of a plurality of battery cells (Cell1 to Cell(m)) excluding at least two battery cells (Cell1 and Cell2) connected with a diagnostic node in between. The diagnostic voltage can be expressed as Equation 1 below.

<Equation 1>

Vdiag = Vbatt - Vcell1 - Vcell2

In Equation 1, Vdiag represents the diagnostic voltage, Vbatt represents the total voltage of the plurality of battery cells (Cell1 to Cell(m)), Vcell1 represents the voltage of the first battery cell (Cell1), and Vcell2) represents the voltage of the first battery cell (Cell1). 2 Indicates the voltage of the battery cell (Cell2). Here, the first battery cell (Cell1) and the second battery cell (Cell2) may be disconnected from other battery cells when a bypass circuit is formed.

The current measurement unit 125 can measure the diagnostic current flowing in the bypass circuit. The current measurement unit 125 can measure diagnostic current at different times from the balancing unit 123.

The main control unit 130 may receive the diagnostic voltage from the balancing unit 123. The main control unit 130 may receive diagnostic current from the current measurement unit 125. The main control unit 130 may calculate the diagnostic resistance of the diagnostic node using the diagnostic voltage and diagnostic current. Hereinafter, the diagnostic resistance calculation process will be described through Equation 2 to Equation 3.

<Equation 2>

Rload,diag = Vdiag / Idiag

In Equation 2, Rload,diag represents the total diagnostic resistance, Vdiag represents the diagnostic voltage, and Idiag represents the diagnostic current.

<Equation 3>

Rdiag = Rload-Rload,diag

In Equation 3, Rdiag represents the diagnostic resistance, Rload represents the load resistance, and Rload,diag represents the total diagnostic resistance.

If it is determined that diagnosis of a node between a plurality of battery cells (Cell1 to Cell(m)) is necessary, the main control unit 130 may select one diagnosis node. The main control unit 130 transmits the selection result to the switch control unit 121 and controls switching of the plurality of switch modules SW1 and SW2 through the switch control unit 121.

The main control unit 130 may compare the diagnostic resistance and the reference resistance. The reference resistance can be set appropriately according to the user's needs. If the diagnostic resistance is greater than the reference resistance, the main control unit 130 may determine that a resistance component has occurred in the diagnostic node. The main control unit 130 may determine that the diagnostic node is in a normal state when the diagnostic resistance is less than the reference resistance.

FIG. 3 is a diagram for explaining the detailed structure of the switch module of FIG. 1.

Figure 3(a) is a diagram showing the structure of a switch module according to the first embodiment. Figure 3(b) is a diagram showing the structure of a switch module according to the second embodiment.

In Figure 3(a), the first switch module (SW1) may be composed of a combination of at least three N-channel MOSFETs (NMOS1, NMOS2, and NMOS3).

In FIG. 3(b), the first switch module SW2 may be composed of a combination of at least three transmissions TR1, TR2, and TR3.

3 (a) and (b), the first switch module SW1 is connected to the positive voltage terminal or negative voltage terminal of at least one battery cell among the plurality of battery cells (Cell1 to Cell (m)). It may include 1 node (Nd1).

Additionally, the first switch module (SW1) may include a second node (Nd2) that is connected to or disconnected from the first node (Nd1) by the first switch elements (NMOS1, TR1).

In addition, the first switch module (SW1) is connected to the first node (Nd1) or to the second node (Nd2) by the second switch elements (NMOS2, TR2) and the third switch elements (NMOS3, TR3). Alternatively, it may include a third node (Nd3) that is disconnected from the first node (Nd1) and the second node (Nd2).

The third node Nd3 of the first switch module SW1 may be connected to the third node of another switch module to form a bypass circuit DT.

Figure 4 is a diagram showing an example of a bypass path that bypasses a battery cell to be diagnosed.

Referring to FIG. 4, the main control unit 130 may select a diagnostic node between the first battery cell (Cell1) and the second battery cell (Cell2). The switch control unit 121 may control switching of the first switch module (SW1) connected to the positive voltage terminal of the first battery cell (Cell1). The switch control unit 121 may control switching of the second switch module (SW2) connected to the negative voltage terminal of the second battery cell (Cell2).

The first switch module (SW1) may have a first node (Nd1) and a third node (Nd3) connected to each other. The second switch module (SW2) may be connected to a second node (Ndb) and a third node (Ndc). The third node (Nd3) of the first switch module (SW1) and the third node (Ndc) of the second switch module (SW2) may be connected. At this time, a bypass circuit (DT) may be formed.

The balancing unit 123 may measure diagnostic voltages of a plurality of battery cells excluding the voltages of the first battery cell (Cell1) and the second battery cell (Cell2).

The current measurement unit 125 can measure the diagnostic current of the bypass circuit (DT).

The main control unit 130 may calculate the diagnostic resistance (Rdiag) between the first battery cell (Cell1) and the second battery cell (Cell2) using the diagnostic voltage and diagnostic current. If the diagnostic resistance Rdiag is greater than or equal to the reference resistance, the main control unit 130 may determine that an unnecessary resistance component has occurred in the diagnostic node. The main control unit 130 can take appropriate action by notifying the outside world of the occurrence of resistance components in the diagnostic node.

Figure 5 is a diagram showing another example of a bypass path that bypasses at least two battery cells to be diagnosed.

Referring to FIG. 5, the main control unit 130 may select a diagnostic node between the second battery cell (Cell2) and the m-1th battery cell (Cell(m-1)). Hereinafter, m is a positive integer. The switch control unit 121 may control switching of the second switch module (SW2) connected to the positive voltage terminal of the second battery cell (Cell2). The switch control unit 121 may control switching of the n-1th switch module (SW(n-1)) connected to the negative voltage terminal of the m-1th battery cell (Cell(m-1)). Hereinafter, n is a positive integer.

The second switch module (SW2) may be connected to the first node (Nd1) and the third node (Nd3). The n-1th switch module (SW(n-1)) may be connected to a second node and a third node. The third node (Nd3) of the second switch module (SW2) and the third node of the n-1th switch module (SW(n-1)) may be connected. At this time, a bypass circuit (DT) may be formed.

The balancing unit 123 may measure the diagnostic voltages of a plurality of battery cells excluding the voltages of the second battery cell (Cell2) and the m-1th battery cell (Cell(m-1)).

The current measurement unit 125 can measure the diagnostic current of the bypass circuit (DT).

The main control unit 130 may calculate the diagnostic resistance (Rdiag) between the second battery cell (Cell1) and the m-1th battery cell (Cell(m-1)) using the diagnostic voltage and diagnostic current. If the diagnostic resistance Rdiag is greater than or equal to the reference resistance, the main control unit 130 may determine that an unnecessary resistance component has occurred in the diagnostic node. The main control unit 130 can take appropriate action by notifying the outside world of the occurrence of resistance components in the diagnostic node.

Figure 6 is a diagram showing another example of a bypass path that bypasses at least two battery cells to be diagnosed.

Referring to FIG. 6, the main control unit 130 may select a diagnostic node between the m-1th battery cell (Cell(m-1)) and the mth battery cell (Cell(m)). The switch control unit 121 may control switching of the third switch module SW3 connected to the positive voltage terminal of the m-1th battery cell (Cell(m-1)). The switch control unit 121 may control switching of the nth switch module (SW(n)) connected to the negative voltage terminal of the mth battery cell (Cell(m)). Hereinafter, n is a positive integer.

In the third switch module (SW3), the first node (Nd4) and the third node (Nd6) may be connected. The nth switch module (SW(n)) may be connected to a second node (Ndf) and a third node (Ndg). The third node (Nd6) of the third switch module (SW3) and the third node (Ndg) of the n-th switch module (SW(n)) may be connected. At this time, a bypass circuit (DT) may be formed.

The balancing unit 123 may measure the diagnostic voltages of a plurality of battery cells excluding the voltages of the m-1th battery cell (Cell(m-1)) and the mth battery cell (Cell(m)).

The current measurement unit 125 can measure the diagnostic current of the bypass circuit (DT).

The main control unit 130 may calculate the diagnostic resistance (Rdiag) between the m-1th battery cell (Cell(m-1)) and the mth battery cell (Cell(m)) using the diagnostic voltage and diagnostic current. . If the diagnostic resistance Rdiag is greater than or equal to the reference resistance, the main control unit 130 may determine that an unnecessary resistance component has occurred in the diagnostic node. The main control unit 130 can take appropriate action by notifying the outside world of the occurrence of resistance components in the diagnostic node.

Figure 7 is a flowchart of a method for detecting resistance between battery cells according to a preferred embodiment of the present invention.

Referring to FIGS. 1, 2, and 7, the method for detecting resistance between battery cells according to a preferred embodiment of the present invention includes a diagnostic node selection step (S710), a bypass circuit forming step (S720), and a current measurement step ( It may include a voltage measurement step (S740), a resistance calculation step (S750), a resistance determination step (S760), an abnormality determination step (S770), and a normal determination step (S780).

In the diagnostic node selection step (S710), when there is concern about a defect or deterioration in the connection state between at least two battery cells among a plurality of battery cells, the main control unit 130 selects a node for diagnosing the state between at least two battery cells. You can select . The main control unit 130 may transmit a signal according to the selection of the diagnostic node to the switch control unit 120.

In the bypass circuit forming step (S720), when the switch control unit 121 receives a signal from the main control unit 130, the switch control unit 121 controls at least two switch modules among a plurality of switch modules to bypass the at least two selected battery cells. can be formed.

In one embodiment, when the diagnostic node between the first battery cell (Cell1) and the second battery cell (Cell2) is selected by the main control unit 130, the switch control unit 120 connects the first battery cell (Cell1) and The first switch module (SW1) and the second switch module (SW2) can be controlled to form a bypass circuit (DT) that bypasses the second battery cell (Cell2). At this time, the first switch module (SW1) may perform a switching operation so that the first node (Nd1) and the third node (Nd3) are connected. The second switch module (SW2) may perform a switching operation so that the second node (Ndb) and the third node (Ndc) are connected. Through this, the third node (Nd3) of the first switch module (SW1) and the third node (Ndc) of the second switch module (SW2) are connected to each other, so that a bypass circuit (DT) can be formed.

In the current measurement step (S730), when the bypass circuit (DT) is formed in the battery array unit 110 according to the switching operation of the plurality of switch modules, the current measurement unit 125 measures the current flowing in the bypass circuit (DT). can do. In one embodiment, the current measurement unit 125 may measure the current (hereinafter referred to as diagnostic current) flowing in the third node (Nd3) of the first switch module (SW1).

In the voltage measurement step (S740), when the bypass circuit (DT) is formed in the battery array unit 110, the balancing unit 123 measures the remaining voltages except for the voltage of at least two battery cells that are disconnected in series with other battery cells. The total voltage (hereinafter referred to as diagnostic voltage) of the battery cell can be measured. The balancing unit 123 may transmit the measured diagnostic voltage to the main control unit 130.

In the resistance calculation step (S750), the main control unit 130 may use the diagnostic current and diagnostic voltage to calculate the diagnostic resistance (Rdiag) between the other battery cell and the battery cell that is disconnected from the series.

In the resistance comparison step (S760), the main control unit 130 may compare the calculated diagnostic resistance (Rdiag) with a preset reference resistance. The reference resistance can be set appropriately according to the user's needs.

In the abnormality determination step (S770), when the diagnostic resistance (Rdiag) is greater than or equal to the reference resistance, the main control unit 130 determines that a resistance component has occurred in the diagnostic node between at least two selected battery cells, and the diagnostic node It can be determined that the connection condition is poor or deteriorated.

In the normal determination step (S780), when the diagnostic resistance Rdiag is less than the reference resistance, the main control unit 130 determines that a resistance component does not occur or is not large between the selected at least two battery cells, and It can be determined that the connection state between the battery cells is normal.

The above description is merely an illustrative explanation of the technical idea of the present invention, and various modifications, changes, and substitutions can be made by those skilled in the art without departing from the essential characteristics of the present invention. will be. Accordingly, the embodiments disclosed in the present invention and the attached drawings are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments and the attached drawings. .

Steps and/or operations according to the invention may occur simultaneously in different embodiments, in different orders, in parallel, for different epochs, etc., as would be understood by those skilled in the art. You can.

Depending on the embodiment, some or all of the steps and/or operations may include executing instructions, programs, interactive data structures, clients and/or servers stored on one or more non-transitory computer-readable media. At least a portion may be implemented or performed using one or more processors. The one or more non-transitory computer-readable media may illustratively be software, firmware, hardware, and/or any combination thereof. Additionally, the functionality of the “modules” discussed herein may be implemented in software, firmware, hardware, and/or any combination thereof.

100: Battery management system
110: Battery array unit
Cell1~Cellm: 1st to mth battery cells
SW1~SW(n): 1st~nth switch module
120: Battery management unit
121: switch control unit
123: Balancing unit
125: Current measuring unit
130: main control unit

Claims (13)

a battery array unit including a plurality of battery cells connected in series with each other and a plurality of switch modules provided between the battery cells;
a battery management unit that forms a bypass circuit that bypasses the at least two selected battery cells to exclude a diagnostic node between the at least two selected battery cells among the plurality of battery cells; and
a main control unit that calculates a diagnostic resistance of the diagnostic node using the diagnostic current flowing in the bypass circuit and the diagnostic voltage of the battery array unit where the bypass circuit is formed;
A battery management system with a resistance detection function including. According to claim 1,
A battery management system with a resistance detection function, wherein each of the plurality of switch modules is composed of a combination of at least three N-channel MOSFETs. According to claim 1,
A battery management system with a resistance detection function, wherein each of the plurality of switch modules is composed of a combination of at least three transmissions. According to claim 1,
Each of the plurality of switch modules,
a first node connected to a positive voltage terminal or a negative voltage terminal of at least one battery cell among the plurality of battery cells;
a second node connected to or disconnected from the first node by at least one switch element; and
a third node connected to the first node, connected to the second node, or disconnected from the first node and the second node by at least two switch elements;
A battery management system with a resistance detection function, comprising: According to claim 4,
A battery with a resistance detection function, wherein the bypass circuit is formed when the first node and the third node in the plurality of switch modules are connected, or the second node and the third node are connected. Management system. According to claim 1,
The battery management unit,
a switch control unit that controls at least two switch modules provided on one side and the other side of each of the at least two selected battery cells;
a balancing unit measuring the diagnostic voltage of the plurality of battery cells excluding the at least two selected battery cells; and
a current measuring unit that measures the diagnostic current flowing in the bypass circuit;
A battery management system with a resistance detection function, comprising: According to claim 1,
The main control unit,
A battery management system with a resistance detection function, characterized in that it compares the diagnostic resistance and a preset reference resistance, and determines whether a resistance component has occurred in the diagnostic node according to the comparison result. According to claim 6,
The main control unit,
A battery management system with a resistance detection function, wherein when it is determined that diagnosis of a node between the plurality of battery cells is necessary, at least one diagnosis node is selected and the selection result is transmitted to the switch control unit. In the method of detecting resistance between battery cells of an electric vehicle, including a plurality of battery cells connected in series with each other and a battery array unit including a plurality of switch modules provided between the battery cells,
A bypass circuit forming step of forming a bypass circuit to bypass the at least two selected battery cells so as to exclude a diagnostic node between the at least two battery cells preselected among the plurality of battery cells;
A current measurement step of measuring diagnostic current flowing in the bypass circuit;
A voltage measurement step of measuring a diagnostic voltage of the battery array unit where the bypass circuit is formed; and
A diagnostic resistance calculation step of calculating a diagnostic resistance of the diagnostic node using the diagnostic current and the diagnostic voltage;
A method of detecting resistance between battery cells comprising: According to clause 9,
Before the bypass circuit forming step, a diagnostic node selection step of selecting the diagnostic node between at least two battery cells among the plurality of battery cells;
A method for detecting resistance between battery cells, further comprising: According to claim 10,
The bypass circuit forming step is,
A first switch module provided at one positive voltage terminal of the at least two selected battery cells is controlled to switch, and a second switch module provided at the other negative voltage terminal of the at least two battery cells is controlled to switch the first switch. A method of detecting resistance between battery cells, characterized in that the bypass circuit is formed by connecting a module and the second switch module. According to clause 9,
A resistance comparison step of comparing the diagnostic resistance with a preset reference resistance;
A method for detecting resistance between battery cells, further comprising: According to clause 9,
An abnormality determination step of determining that a resistance component has occurred in the diagnostic node when the diagnostic resistance is greater than the reference resistance; and
a normal determination step of determining that the diagnostic node is in a normal state when the diagnostic resistance is less than the reference resistance;
A method for detecting resistance between battery cells, further comprising:

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