KR20230025186A - Apparatus for maintaining battery cells - Google Patents

Abstract

The present invention relates to an apparatus that separates a battery cell with high internal resistance from a battery module and connects an independent power source corresponding to the cell voltage of the battery cell to the battery module. The apparatus for maintaining and managing a battery cell according to one embodiment of the present invention comprises: a battery module consisting of a plurality of battery cells connected in series; a test circuit connected to both ends of each battery cell; a power pack consisting of a plurality of independent power sources connected in series and connected to one end of the battery module; and a processor that separates the battery cell from the battery module according to the size of the internal resistance of the battery cell identified by the test circuit and connects the independent power source corresponding to the separated battery cell to the battery module.

Description

Battery cell maintenance device {APPARATUS FOR MAINTAINING BATTERY CELLS}

The present invention relates to a device for separating a battery cell having a high internal resistance from a battery module and connecting an independent power source corresponding to a cell voltage of the corresponding battery cell to the battery module.

An energy storage system (ESS) is a system that converts AC electricity supplied from a grid into DC electricity, stores it in a battery, and provides the electricity stored in the battery to a load as needed.

A battery included in the ESS includes a plurality of battery cells. Specifically, the ESS includes a battery rack. The battery rack is composed of a plurality of battery modules, and the battery module is composed of a plurality of battery cells connected in series.

On the other hand, it has been confirmed that the main cause of recent ESS fire accidents is that local overheating of the battery causes a fire to start and spread to the entire system. For example, when an overvoltage is applied to a battery cell, insulation is destroyed between a negative electrode and a positive electrode, resulting in a short circuit, which may cause a fire. In addition, even if overvoltage is not applied, damage to the separator that separates the cathode and anode, and the increase in internal resistance of the battery cell due to poor bonding between the cathode and anode materials and the electrode plate may also generate abnormal heat during charging and discharging, which may cause a fire. .

In particular, an increase in the internal resistance of a battery cell generates Joule's heat due to charging and discharging current, which not only shortens the lifespan of the battery, but also can lead to a fire accident. It is necessary to identify the internal resistance of the battery and exclude a battery cell having a high internal resistance from the entire battery configuration.

An object of the present invention is to identify the internal resistance of each battery cell.

In addition, an object of the present invention is to control a connection state between a corresponding battery cell and another battery cell according to the internal resistance of the battery cell.

In addition, an object of the present invention is to connect an independent power source corresponding to a battery cell separated from a battery module to a battery module.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned above can be understood by the following description and will be more clearly understood by the examples of the present invention. It will also be readily apparent that the objects and advantages of the present invention may be realized by means of the instrumentalities and combinations indicated in the claims.

A battery cell maintenance device according to an embodiment of the present invention for achieving the above object is a battery module composed of a plurality of battery cells connected in series, a test circuit connected to both ends of each battery cell, and a plurality of independent power sources connected in series. The battery cell is separated from the battery module according to the size of the internal resistance of the battery cell identified through the power pack configured and connected to one end of the battery module and the test circuit, and an independent corresponding to the separated battery cell. It characterized in that it comprises a processor for connecting power to the battery module.

In one embodiment, the test circuit includes a test resistor, a first switch connecting the test resistor and one end of the battery cell, a second switch connected in parallel to both ends of the battery cell, and a current sensor connected in series with the test resistor. and a voltage sensor connected in parallel with both ends of the battery cell.

In one embodiment, the processor selectively connects the test circuit and the battery cell, and the battery cell based on a voltage change across the battery cell occurring before and after the test circuit is connected and a test current flowing through the test circuit. Characterized in identifying the internal resistance of.

In one embodiment, the processor may identify the internal resistance by dividing a difference between a voltage across the battery cell before the test circuit is connected and a voltage across the battery cell after the test circuit is connected, by the test current.

In one embodiment, the processor calculates a difference between the voltage across the battery cell measured in a state in which the first switch is turned off and the voltage across the battery cell measured in a state in which the first switch is controlled to be turned on, and It is characterized in that the internal resistance is identified by dividing by the test current measured in a state in which the switch is turned on and controlled.

In one embodiment, the processor may separate the battery cell from the battery module when the internal resistance exceeds a reference value.

In one embodiment, the processor may turn on the second switch when the internal resistance exceeds a reference value.

In one embodiment, the processor identifies the number of separated battery cells, identifies cell voltages corresponding to the identified number, and connects independent power sources corresponding to the identified cell voltages to the battery module. It is characterized by doing

In one embodiment, each of the plurality of independent power sources is characterized in that connected through a switch.

In one embodiment, the processor may control the switch to connect an independent power source corresponding to the separated battery cell to the battery module.

The present invention can monitor the fire risk of each battery cell by identifying the internal resistance of each battery cell.

In addition, the present invention can fundamentally prevent the risk of fire due to an increase in the internal resistance of the battery cell by separating the battery cell having a high internal resistance from the battery module.

In addition, the present invention can maintain the entire voltage of the battery module by connecting an independent power source corresponding to a battery cell separated from the battery module to the battery module, thereby preventing performance degradation of the ESS.

In addition to the effects described above, specific effects of the present invention will be described together while explaining specific details for carrying out the present invention.

1 is a diagram illustrating a battery cell maintenance device according to an embodiment of the present invention.
2 is an equivalent circuit diagram of a battery cell.
3 is an equivalent circuit diagram of a battery module;
4 and 5 are diagrams showing how the battery module is charged or discharged.
6 is a diagram showing a state in which a test circuit according to an embodiment of the present invention is connected to a battery cell.
7 is a diagram showing a state in which a test circuit according to an embodiment of the present invention is connected to a battery module;
8 and 9 are diagrams for explaining a method of identifying internal resistance of a battery cell when the battery cell is charged or discharged;
10 is a diagram illustrating disconnection of a specific battery cell from a battery module;
Fig. 11 is an equivalent circuit diagram of the circuit shown in Fig. 10;
12 is a diagram showing a power pack according to an embodiment of the present invention.
FIG. 13 is a view showing how the power pack shown in FIG. 12 is connected to a battery module;
14 is a diagram illustrating a state in which an independent power source is connected to a battery module instead of a specific battery cell being separated from the battery module.

The above objects, features and advantages will be described later in detail with reference to the accompanying drawings, and accordingly, those skilled in the art to which the present invention belongs will be able to easily implement the technical spirit of the present invention. In describing the present invention, if it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

In this specification, first, second, etc. are used to describe various components, but these components are not limited by these terms, of course. These terms are only used to distinguish one component from another component, and unless otherwise stated, the first component may be the second component, of course.

In addition, in the present specification, when a component is described as being “connected”, “coupled” or “connected” to another component, the components may be directly connected or connected to each other, but other components may be present between each component. It should be understood that elements may be “interposed,” or that each element may be “connected,” “coupled,” or “connected” through other elements.

Also, singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "consisting of" or "comprising" should not be construed as necessarily including all of the various components or steps described in the specification, and some of the components or some of the steps It should be construed that it may not be included, or may further include additional components or steps.

In addition, in this specification, when "A and / or B", unless otherwise specified, it means A, B or A and B, and when "C to D", it means a special opposite Unless otherwise specified, it means more than C and less than D

The present invention relates to a device for separating a battery cell having a high internal resistance from a battery module and connecting an independent power source corresponding to a cell voltage of the corresponding battery cell to the battery module. Hereinafter, a battery cell maintenance device according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 14 .

1 is a diagram illustrating a battery cell maintenance device according to an embodiment of the present invention.

2 is an equivalent circuit diagram of a battery cell, and FIG. 3 is an equivalent circuit diagram of a battery module.

4 and 5 are views showing how the battery module is charged or discharged.

6 is a diagram showing a state in which a test circuit according to an embodiment of the present invention is connected to a battery cell, and FIG. 7 is a diagram showing a state in which a test circuit according to an embodiment of the present invention is connected to a battery module.

8 and 9 are views for explaining a method of identifying internal resistance of a battery cell when the battery cell is charged or discharged.

FIG. 10 is a diagram illustrating disconnection of a specific battery cell from a battery module, and FIG. 11 is an equivalent circuit diagram of the circuit shown in FIG. 10 .

12 is a diagram showing a power pack according to an embodiment of the present invention, and FIG. 13 is a diagram showing how the power pack shown in FIG. 12 is connected to a battery module.

14 is a diagram illustrating a state in which an independent power source is connected to a battery module instead of a specific battery cell being separated from the battery module.

Referring to FIG. 1 , a battery cell maintenance device 1 according to an embodiment of the present invention includes a battery module 10, a test circuit 20, a power pack 30, a processor 40, and a processor 40. ) may include a memory (not shown) for the operation of. However, the battery cell maintenance device 1 shown in FIG. 1 is according to an embodiment, and its components are not limited to the embodiment shown in FIG. 1, and some components are added or changed as needed. or can be deleted.

The battery module 10 may include a plurality of battery cells 11 connected in series. Here, the battery cell 11 is used for a secondary battery and may be composed of a voltage source (Vb) for charging and discharging and an internal resistance (Rs).

Referring to FIG. 2 , the battery cell 11 may be equivalent to a circuit in which a voltage source Vb and an internal resistance Rs are connected in series. At this time, since the voltage source Vb is a circuit element capable of charging and discharging, it may be illustrated as a capacitor. Hereinafter, for convenience of description, the voltage source included in the battery cell 11 will be referred to as a cell voltage Vb.

A plurality of such battery cells 11 may be connected in series to configure the battery module 10 .

Referring to FIG. 3 as an example, the battery cell 11 may be configured by connecting 60 battery cells 11 in series. As described in FIG. 2 , each battery cell 11 may include a cell voltage Vb and an internal resistance Rs.

Such a battery module 10 may be charged or discharged by being connected to the charging/discharging circuit 100 . More specifically, the battery module 10 may be connected to the charge/discharge circuit 100 and may be charged or discharged according to the voltage level of the charge/discharge circuit 100 .

Referring to FIGS. 4 and 5 together, each battery cell 11 constituting the battery module 10 may have a cell voltage Vb of 3.7 [V], and the battery module 10 includes a charge/discharge circuit. (100) can be connected. Meanwhile, the charge/discharge circuit 100 includes a charge/discharge voltage (Vs) and a charge/discharge resistance (R _L ), where the charge/discharge resistance (R _L ) is an internal resistance of the charge/discharge circuit 100 and a charge/discharge loss. It may be a circuit element for representing.

Since 60 battery cells 11 having a cell voltage Vb of 3.7 [V] are connected, the voltage of the battery module 10 is 222 [V], and as shown in FIG. When the voltage of the battery module 10 is 228 [V], current flows toward the battery module 10 and the battery module 10 can be charged. On the other hand, as shown in FIG. 5, when the charge/discharge voltage (Vs) is 216 [V] smaller than the voltage of the battery module 10, current flows toward the charge/discharge circuit 100 and the battery module 10 is discharged. can

According to the above method, each battery cell 11 constituting the battery module 10 may be charged and discharged. At this time, when the internal resistance (Rs) of the specific battery cell 11 increases due to internal and / or external factors, Joule's heat is generated due to the charging and discharging current, and when the heating value is large, the corresponding battery cell ( A fire may start in 11) and cause a fire in the battery module 10 and the entire ESS including the battery module 10 .

In order to solve this problem, the present invention monitors the internal resistance (Rs) of the battery cell 11 using the test circuit 20, and disconnects the battery cell 11 having a high internal resistance (Rs) to internal resistance (Rs). It is possible to prevent a fire caused by an increase in resistance (Rs) in advance.

Hereinafter, specific operations of the present invention will be described.

The test circuit 20 may be connected to both ends of each battery cell 11 , and the processor 40 may selectively connect the test circuit 20 and the battery cell 11 . More specifically, the test circuit 20 may be connected to both ends of the battery cell 11 through a switch, and the processor 40 electrically connects or connects the test circuit 20 and the battery cell 11 by controlling the switch. can be released

Referring to FIG. 6 , the test circuit 20 may be connected to both ends of the battery cell 11 . The test circuit 20 includes a test resistance Rt, a first switch S1 connecting the test resistance Rt and one end of the battery cell 11, and a second switch connected in parallel to both ends of the battery cell 11 ( S2), a current sensor A connected in series with the test resistance Rt, and a voltage sensor V connected in parallel with both ends of the battery cell 11. However, the test circuit 20 shown in FIG. 6 is according to one embodiment, and its components are not limited to the embodiment shown in FIG. 6, and some components may be added, changed, or deleted as necessary. can

Meanwhile, in FIG. 6, only a state in which the test circuit 20 is connected to both ends of any one battery cell 11 is shown, but this is for convenience of description, and the test circuit 20 is all battery cells constituting the battery module 10. (11) can be connected to both ends respectively. Accordingly, although only a single test circuit 20 is mainly illustrated and described below, it is natural that the operation described later can be applied to all test circuits 20 connected to each battery cell 11 .

The processor 40 may generate a control signal Sc for opening and closing the first and second switches S1 and S2, and the first and second switches S1 and S2 respond to the corresponding control signal Sc. can operate accordingly. Specifically, the first switch S1 can be opened and closed according to the first control signal Sc1, and the second switch S2 can be opened and closed according to the second control signal Sc2.

To this end, the first and second switches S1 and S2 may be implemented as power switching devices. For example, the first and second switches S1 and S2 may be implemented as an Insulated-Gate Bipolar Transistor (IGBT), a Bipolar Junction Transistor (BJT), a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), or the like.

On the other hand, the current sensor (A) may measure the test current (It) to be described later and provide it to the processor 40, and the voltage sensor (V) may measure the voltage (Vt) across the battery cell 11 and measure the voltage (Vt) of the battery cell 11 to the processor 40. ) can be provided. The processor 40 may identify the internal resistance Rs of the battery cell 11 through calculation using values provided from the sensors A and V.

Hereinafter, the operation of the processor 40 will be described in detail.

The processor 40 selectively connects the test circuit 20 to the battery cell 11, and the voltage change across the battery cell 11 generated before and after the connection of the test circuit 20 and the voltage flowing through the test circuit 20 Based on the test current It, the internal resistance Rs of the battery cell 11 can be identified.

Referring to FIG. 7 , the test circuit 20 may be connected to the first battery cell 11, and the processor 40 controls the first switch S1 to turn on/off the test circuit 20 for the first battery. It can be selectively connected to the cell 11.

When the test circuit 20 is connected to the first battery cell 11, some of the current for charging or discharging the battery cell 11 may flow into the test circuit 20. The processor 40 measures the voltage across the battery cell 11 generated before and after the connection of the test circuit 20, and measures the test current It flowing into the test circuit 20 after the connection of the test circuit 20. Internal resistance (Rs) of the battery cell 11 may be identified.

More specifically, the processor 40 tests the difference between the voltage (Vt) across the battery cell 11 before the connection of the test circuit 20 and the voltage (Vt) across the battery cell 11 after the connection of the test circuit 20. The internal resistance Rs of the battery cell 11 can be identified by dividing by the current It. The principle of identifying the internal resistance (Rs) in this way will be described below, and below, for convenience of explanation, the voltage (Vt) across the battery cell 11 before the test circuit 20 is connected to the off voltage. (Voff), after connecting the test circuit 20, the voltage (Vt) of both ends of the battery cell 11 is expressed as the on-voltage (Von).

When the battery module 10 shown in FIG. 7 is being charged, the circuit shown in FIG. 7 may be equivalent as shown in FIG. 8, and when the battery module 10 shown in FIG. 7 is being discharged, the circuit shown in FIG. The circuit can be equalized as shown in FIG. 9 .

8 and 9, the composite voltage (Vc) is the cell voltage (Vb) of all battery cells 11 except for the battery cell 11 to which the test circuit 20 is connected in the charge and discharge voltage (Vs). It can be defined as a subtracted value (Vs-(Vb2+Vb3+...+Vb60)), and the combined resistance (Rc) is the internal resistance ( Rs) and the charge/discharge resistance (R _L ) (R _L +Rs2+Rs3+…+Rs60).

When the first switch S1 is in an off state, the off voltage may satisfy an equation such as Equation 1 below, and the circuit shown in FIG. ] can satisfy the same equation.

Meanwhile, when the first switch S1 is in an on state, the test current It flowing through the test circuit 20 may satisfy the equation as shown in [Equation 3] below, and the circuit shown in FIG. 8 is a Kirchhoff According to the law, an equation such as [Equation 4] below can be satisfied.

가 성립할 수 있으며, 이에 따라 [수학식 5]는 [수학식 6]과 같이 근사될 수 있다.When [Equation 4] is substituted into [Equation 3], an equation as in [Equation 5] below is established, and the combined resistance is much greater than the internal resistance (Rs1) of a single battery cell 11.

can be established, and thus [Equation 5] can be approximated as in [Equation 6].

According to the equations described above, the processor 40 calculates the voltage (Vt) across the battery cell 11 before the connection of the test circuit 20 and the voltage (Vt) across the battery cell 11 after the connection of the test circuit 20. The internal resistance (Rs) of the battery cell 11 can be identified by dividing the difference between the test current (It).

More specifically, the processor 40 may measure the off voltage through the voltage sensor V in a state in which the first switch S1 is off-controlled. Subsequently, the processor 40 may measure the on-voltage through the voltage sensor V and measure the test current It through the current sensor A while the second switch S2 is turned on. there is. The processor 40 may identify a value obtained by dividing the difference between the off voltage and the on voltage by the test current It as the internal resistance Rs of the battery cell 11 as shown in [Equation 6].

The processor 40 may identify the internal resistance Rs of the battery cell 11 by connecting the test circuit 20 and the battery cell 11 according to a preset test period. Here, the preset test cycle may be arbitrarily set by the user.

Real-time monitoring of the battery cell 11 may be provided due to the setting of the test period. For example, when the user sets the test cycle to 1 minute, the processor 40 can identify the internal resistance (Rs) of the battery cell 11 every minute, and the user sets the battery cell 11 every minute. ) can be monitored for abnormalities.

On the other hand, since the method for identifying the internal resistance (Rs) described above uses the voltage (Vt) and the test current (It) at a specific point in time, noise may occur in identifying the internal resistance (Rs). To prevent this, the processor 40 connects the test circuit 20 and the battery cell 11 according to a preset frequency, and calculates the Root Mean Square (RMS) value of the voltage (Vt) across the battery cell 11. The internal resistance (Rs) of the battery cell 11 may be identified based on the effective value of the test current (It) and the test current (It).

For example, the processor 40 may turn on/off the first switching element according to a cycle of 500 [Hz]. In this case, the above-described off voltage, on voltage, and test current (It) all have an AC waveform having a frequency of 500 [Hz], and the processor 40 calculates the effective value of each voltage (V _off , V _on ) and , the internal resistance Rs of the battery cell 11 can be identified using the effective value of the test current It. Specifically, the processor 40 may identify the internal resistance Rs according to Equation 7 below.

In this way, when the internal resistance Rs is identified using the effective value, accuracy in identifying the internal resistance Rs can be increased.

As described above, the present invention can accurately identify the internal resistance (Rs) of each battery cell 11 in real time, and accordingly, the user can monitor the fire risk of each battery cell 11 .

The processor 40 may separate the battery cell 11 from the battery module 10 according to the magnitude of the internal resistance Rs identified by the method described above.

More specifically, the processor 40 may compare the internal resistance (Rs) of each battery cell 11 with a reference value, and as a result of the comparison, if the internal resistance (Rs) of the battery cell 11 is less than or equal to the reference value, the corresponding battery cell 11 ) and other battery cells 11 may be maintained. On the other hand, if the internal resistance Rs of a specific battery cell 11 exceeds the reference value, the connection between the corresponding battery cell 11 and other battery cells 11 may be disconnected.

In other words, the processor 40 may separate a battery cell 11 having an internal resistance Rs exceeding a reference value among a plurality of battery cells 11 constituting the battery module 10 from the battery module 10 . . Here, the reference value may be arbitrarily set by the user, and may be set to a value lower than the limit resistance that the battery cell 11 can endure.

Referring to FIG. 10 , the processor 40 may determine that the internal resistance Rs1 of the first battery cell 11 exceeds a reference value, and the remaining battery cells 11 excluding the first battery cell 11 It can be determined that the internal resistance (Rs2, Rs3, ..., Rs60) of is less than the reference value. At this time, the processor 40 turns on the second switch S2 of the test circuit 20 connected to the first battery cell 11 to separate the first battery cell 11 from the other battery module 10. can

When the second switch S2 is controlled to be turned on, the second switch S2 may form a bypass path, and the charge/discharge current flowing in the first battery cell 11 is passed through the bypass path, that is, the second switch S2 It can flow to switch S2.

Referring to FIG. 11, when the second switch S2 of the test circuit 20 connected to the first battery cell 11 forms a bypass path, the battery module 10 is connected as shown in FIG. can That is, the first battery cell 11 having a high internal resistance Rs may be separated from the battery module 10 .

As described above, the present invention can fundamentally prevent the risk of fire due to the increase in the internal resistance (Rs) of the battery cell 11 by separating the battery cell 11 having a high internal resistance (Rs) from the battery module 10. there is.

According to the method described above, the present invention can separate the battery cell 11 with a possibility of deterioration from the battery module 10 . However, as the number of battery cells 11 separated from the battery module 10 increases, the magnitude of the overall voltage of the battery module 10 decreases, and the corresponding battery module 10 is charged using the same charge/discharge circuit 100. Or, when discharging, the charge/discharge current increases, and problems in the ESS system due to overcurrent may occur.

Referring to FIG. 4 as an example, each of the 60 battery cells 11 constituting the battery module 10 may have a cell voltage Vb of 3.7 [V]. Assuming that 20 of the 60 battery cells 11 are separated from the battery module 10 due to the operation of the processor 40 described above, the total voltage of the battery module 10 is 222 [V] to 148 [V]. can be lowered At this time, when the battery module 10 is charged with the charge/discharge circuit 100 having a charge/discharge voltage (Vs) of 228 [V], the potential difference between the battery module 10 and the charge/discharge voltage (Vs) increases. Charging by overcurrent may be performed, and if the overcurrent continues, problems may occur in the entire ESS system.

In order to solve this problem, the present invention can supplement the cell voltage Vb of the separated battery cell 11 . Hereinafter, the power supply operation of the present invention will be described in detail.

The power pack 30 is composed of a plurality of independent power sources Vi connected in series and can be connected to one end of the battery module 10, and the processor 40 selectively connects the battery module 10 and the power pack 30. can make it More specifically, the power pack 30 may be connected to one end of the battery module 10 through a switch, and the processor 40 electrically connects or connects the power pack 30 and the battery module 10 by controlling the switch. connection can be disconnected.

Referring to FIG. 12, n independent power sources Vi1, Vi2, ..., Vin constituting the power pack 30 may be connected through a power switch Si connected between each independent power source Vi. In addition, each independent power source Vi may be grounded through a grounding switch Sg. Here, the voltage of each independent power source Vi may be the same or different. However, in the following description, it is assumed that the voltage of each independent power source Vi is the same for convenience of description.

The processor 40 controls the power switch Si and/or the ground switch Sg to provide an independent power source Vi corresponding to the battery cell 11 separated from the battery module 10 to the battery module 10. can be connected.

Referring to FIG. 13 , a power pack 30 may be connected to one end of the battery module 10 . The processor 40 turns off the battery ground switch Sm connected to the end of the battery module 10 and controls the power switch Si and the ground switch Sg included in the power pack 30 to turn off the battery module 10. and the power pack 30 can be connected. For example, the processor 40 turns off the battery ground switch Sm, controls the first power switch Si1 and the first ground switch Sg1 to turn on, and controls the second power switch Si2 to turn off, A first independent power source Vi1 may be connected to the battery module 10 .

The processor 40 may identify the number of battery cells 11 separated from the battery module 10 and identify cell voltages Vb corresponding to the identified number. Subsequently, the processor 40 may connect the number of independent power sources Vi corresponding to the identified cell voltages Vb to the battery module 10 .

Referring to FIG. 14, among the 60 battery cells 11 constituting the battery module 10, the internal resistances Rs1 and Rs3 of the two battery cells 11 may exceed the reference value, and thus the two battery cells 11 (11) can be separated from the battery module (10). At this time, the processor 40 may identify the number of separated battery cells 11 . For example, the processor 40 may count the second control signal Sc2 for turning on the second switch S2 and identify the number of battery cells 11 as two.

Subsequently, the processor 40 may identify cell voltages Vb corresponding to the identified number. As in the example shown in FIG. 4 , when the cell voltage Vb of each battery cell 11 is 3.7 [V], the processor 40 determines the cell voltage corresponding to the number (two) of the separated battery cells 11 . (Vb) can be identified as 7.4[V].

Meanwhile, the voltage of each independent power source Vi constituting the power pack 30 may also be 3.7 [V]. At this time, the processor 40 may identify the number of independent power sources Vi corresponding to the previously identified cell voltage (7.4 [V]) as two, and convert the corresponding number of independent power sources Vi to the battery module 10 ) can be connected.

More specifically, the processor 40 controls the battery ground switch Sm off, controls the first and second power switches Si1 and Si2 on, controls the first ground switch Sg1 off, and The first and second independent power sources Vi1 and Vi2 may be connected to the battery module 10 by controlling the second ground switch Sg2 to be turned on and the third power switch Si3 to be turned off.

Unlike the previous assumption, if the voltage of each independent power source Vi is 7.4 [V], the processor 40 counts the number of independent power sources Vi corresponding to the cell voltage identified above (7.4 [V]) as one. , and only the first independent power source Vi1 can be connected to the battery module 10 .

As described above, the present invention can maintain the entire voltage of the battery module 10 by connecting the independent power source Vi corresponding to the battery cell 11 separated from the battery module 10 to the battery module 10, , it is possible to prevent performance degradation of the ESS through this.

As described above, the present invention has been described with reference to the drawings illustrated, but the present invention is not limited by the embodiments and drawings disclosed in this specification, and various modifications are made by those skilled in the art within the scope of the technical idea of the present invention. It is obvious that variations can be made. In addition, although the operational effects according to the configuration of the present invention have not been explicitly described and described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be recognized.

Claims (10)

A battery module composed of a plurality of battery cells connected in series;
A test circuit connected to both ends of each battery cell;
A power pack composed of a plurality of independent power sources connected in series and connected to one end of the battery module; and
A processor for separating the battery cell from the battery module according to the size of the internal resistance of the battery cell identified through the test circuit and connecting an independent power source corresponding to the separated battery cell to the battery module
Battery cell maintenance device.
According to claim 1,
The test circuit
test resistance,
A first switch connecting the test resistance and one end of the battery cell;
A second switch connected in parallel to both ends of the battery cell;
A current sensor connected in series with the test resistance and
Including a voltage sensor connected in parallel with both ends of the battery cell
Battery cell maintenance device.
According to claim 1,
The processor selectively connects the test circuit and the battery cell, and identifies the internal resistance of the battery cell based on a voltage change across the battery cell occurring before and after the test circuit is connected and a test current flowing through the test circuit. doing
Battery cell maintenance device.
According to claim 3,
The processor identifies the internal resistance by dividing the difference between the voltage across the battery cell before connection of the test circuit and the voltage across the battery cell after connection of the test circuit by the test current
Battery cell maintenance device.
According to claims 2 and 3,
The processor determines the difference between the voltage across the battery cell measured while controlling the first switch to be off and the voltage across the battery cell measured while controlling the first switch to be turned on. Identifying the internal resistance by dividing by the test current measured in the state
Battery cell maintenance device.
According to claim 1,
The processor separates the battery cell from the battery module when the internal resistance exceeds a reference value.
Battery cell maintenance device.
According to claim 2,
The processor turns on the second switch when the internal resistance exceeds a reference value.
Battery cell maintenance device.
According to claim 1,
The processor identifies the number of separated battery cells, identifies a cell voltage corresponding to the identified number, and connects independent power sources corresponding to the identified cell voltage to the battery module.
Battery cell maintenance device.
According to claim 1,
Each of the plurality of independent power sources is connected through a switch
Battery cell maintenance device.
According to claim 9,
The processor controls the switch to connect an independent power source corresponding to the separated battery cell to the battery module.
Battery cell maintenance device.

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