KR102451089B1 - Battery monitoring circuit having a circuit detecting transient voltage in battery cell - Google Patents

Abstract

According to the present invention, disclosed is a battery monitoring circuit, which includes one or more transient voltage detectors which respectively corresponds to at least one battery cell and detects the transient voltage of the corresponding battery cell based on an AC component obtained by removing the DC component of the cell voltage of the corresponding battery cell. Through this, the present invention detects a change in transient voltage due to an internal short circuit of the battery cell and detects a defective battery cell, and thus it is possible to prevent a fire or explosion of the battery due to the internal short circuit, and to present a criterion for determining reuse of the battery cell according to the presence or absence of the internal short circuit.

Description

Battery monitoring circuit having a circuit detecting transient voltage in battery cell

The present invention relates to a battery monitoring circuit, and more particularly, by detecting a change in transient voltage caused by an internal short circuit of a battery cell and detecting a bad battery cell, prevents a fire or explosion of a battery due to an internal short circuit, and prevents an internal short circuit It relates to a battery monitoring circuit capable of presenting a criterion for determining the reuse of a battery cell according to the presence or absence of a.

Lithium-ion batteries are commonly applied as energy storage devices such as electric vehicles, energy storage systems (ESSs) and uninterruptible power supplies as well as portable devices.

Unlike small-capacity batteries applied to portable devices, in the case of medium-to-large or larger batteries applied to electric vehicles or energy storage systems, a high-capacity battery device is typically implemented and used by connecting a plurality of battery cells in series or in series/parallel. will do

Such a high-capacity battery device includes a plurality of battery cells connected in series or in series/parallel, and a cell monitoring unit (CMU) for measuring and monitoring at least one parameter of the battery cells, such as voltage and temperature of the battery cells, and , may be implemented as a battery pack or a battery module including a battery monitoring unit (BMU) that manages the battery cells based on the state information of the battery cells.

1 is an exemplary view of a conventional battery device.

Referring to FIG. 1 , a conventional battery device is composed of a plurality of battery cells 11 connected in series to a charging/discharging cable 20 , various control devices, communication means with internal and external communication means and wiring, and the like, in an electric vehicle. This is also referred to as a battery pack. The plurality of battery cells 11 may be grouped into a plurality of battery modules 10 in consideration of the efficiency of managing and assembling the battery cells 11 in the battery pack.

A conventional battery device, a plurality of cell monitoring units (CMU, Cell Monitoring Unit, 12) having a direct electrical connection with the battery cells 11 of the battery module 10 for each of the battery modules 10, and a plurality of CMUs 12 and a battery monitoring unit (BMU, Battery, Battery Monitoring Unit, 30) that transmits and receives status information and control information of the battery cell 11 and controls the overall operation of the battery pack with a complex software program.

Until now, most battery devices are composed of one BMU 30 and a plurality of CMUs 12 , and one CMU 12 per battery module 10 is matched to implement a battery monitoring and control function. At this time, the CMU 12 includes a battery monitoring circuit (BMC, Battery Monitoring Circuit) electrically connected to the battery cell 11 to monitor the state of the battery cell 11 or control the operation of the battery cell 11 . The BMC is typically connected to a plurality of battery cells 11 in the battery module 10 and a conductive cell measurement wire (WCM, Wire Harness for Cell Measurement) to measure and monitor the state of the battery cells 11 and , it consists of one multi-cell battery monitoring IC (MCBMIC, Multi-Cell Battery Monitoring Integrated Circuit) that performs a discharge function if necessary.

At this time, it is a general requirement of the CMU 12 that the state of the battery cell 11 should be measured very precisely in order to maximize the battery management performance.

However, in the related art, since the length of the cell measurement wiring (WCM) and the via path are different for each battery cell 11, a difference occurs in the measurement parameters, and the section connected to a specific position with a single line is significantly exposed, which is vulnerable to common mode noise. there is a problem.

In addition, the conventional BMC uses one or two analog-to-digital converters (ADCs) that measure or monitor the state of the battery cells 11, and a multiplexer between the battery cells 11 and the ADCs. 11) is monitored, so when the selected battery cell 11 is being measured or monitored by the multiplexer, the unselected battery cell 11 cannot be measured or monitored. That is, there is a problem in that the states of all the battery cells 11 cannot be simultaneously measured or monitored and cannot be monitored during most of the operation time or in real time.

In particular, the conventional BMC has a problem in that it cannot accurately detect in real time an internal short circuit (ISC) or a micro short circuit (MSC) that occurs instantaneously inside the battery cell 11 and the resulting transient voltage. have. Accordingly, there is a problem in that it is difficult to prevent failure of the battery cell 11, fire, and explosion in advance because the battery cell 11 having a symptom of a problem cannot be detected.

2 is a circuit of an internal short circuit model of the battery cell 11 for explaining the internal short circuit of the battery cell 11, and FIG. 3 is an internal short circuit resistance (R _ISC ) when an internal short circuit occurs in the battery cell 11 . It is a graph showing the change of the drop voltage (V _DROP ) according to the

Internal short circuit or micro short circuit refers to a phenomenon in which internal and instantaneous short circuits occur internally and instantaneously by dendrites growing on the negative electrode with a separator interposed therebetween during charging of the battery cell 11, and intermittently occurring internal short circuit is the battery cell ( 11) weakens the inside of the battery or induces a more serious internal short circuit, eventually causing a thermal runaway, which may cause a fire or explosion of the battery.

In the battery cell 11 in which the internal short circuit occurs, the cell internal resistance Rs, the internal short circuit resistance R _ISC and the short circuit switch SW _ISC may be modeled as shown in FIG. 2 .

According to FIG. 2 , when an internal short circuit occurs, the short circuit switch SW _ISC is closed and a short circuit current I _ISC flows inside the cell, and the cell short circuit voltage VB _ISC is the cell voltage VB versus the drop voltage V _DROP ) as much as a voltage drop in the form of a transient voltage occurs. At this time, the generated drop voltage (V _DROP ) is given as in Equation 1 below, and changes in the form shown in FIG. 3 according to the value of the internal short-circuit resistance (R _ISC ).

[Equation 1]

Referring to FIG. 3 , assuming that the cell internal resistance Rs is 1 mohm and the internal short circuit resistance R _ISC is 1 ohm, the drop voltage V _DROP is only about 4 mV when an internal short circuit occurs.

An internal short circuit occurs randomly in time and may occur and then disappear in the form of an instantaneous transient voltage, and the phenomenon may become serious or disappear depending on the usage state and operating environment of the battery.

As it approaches the thermal runaway threshold, the size of the internal short circuit resistance (R _ISC ) becomes smaller and accordingly, the voltage drop (V _DROP ) due to the internal short circuit also increases. It should be detected, and since the cell internal resistance Rs decreases as the capacity of the battery cell 11 increases, a technology capable of detecting an excessive voltage caused by a very small drop voltage V _DROP is required.

Therefore, the present invention has been devised to solve the problems of the prior art, and by detecting a change in transient voltage due to an internal short circuit of a battery cell and detecting a defective battery cell, a fire or explosion of the battery due to an internal short circuit is prevented, An object of the present invention is to provide a battery monitoring circuit capable of presenting a criterion for determining the reuse of a battery cell according to the presence or absence of an internal short circuit.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. will be able

In order to achieve the above object, the battery monitoring circuit according to the present invention is a battery monitoring circuit configured to monitor the state or control the operation of one or more battery cells connected in series, and convert the cell voltage of the battery cell to a digital value. ADC (analog-to digital coverter) to convert to; and one or more transient voltage detection units corresponding to at least one or more of the one or more battery cells connected in series, respectively, and detecting the transient voltage of the corresponding battery cell based on an AC component from which a DC component of the cell voltage of the corresponding battery cell is removed. including, wherein each of the one or more transient voltage detection units includes: a direct current removing unit providing an alternating current component by removing a direct current component of a cell voltage of the corresponding battery cell; an amplifying unit amplifying the AC component; and a comparator configured to detect a transient voltage by comparing the amplified AC component with a predetermined threshold level, wherein the transient voltage includes a voltage randomly generated in time during charging of the battery cell do.

delete

Each of the one or more transient voltage detection units may include: a DC removal unit configured to respectively output an AC component by removing a DC component of a positive voltage and a DC component of a negative voltage of the corresponding battery cell; an amplifying unit for amplifying a difference between AC components output from the DC removing unit; and a comparator for detecting an overvoltage by comparing the difference between the amplified AC components with a predetermined threshold level.

Each of the one or more transient voltage detection units may include: a DC removal unit configured to output an AC component by removing a DC component of any one of a positive voltage or a negative voltage of the corresponding battery cell; an amplifying unit amplifying the AC component; and a comparator for detecting an overvoltage by comparing the amplified AC component with a predetermined threshold level.

The transient voltage detection unit is provided with at least two or more corresponding to at least two or more of the plurality of battery cells connected in series, and compares the AC component or the transient voltage detection result of each of the at least two or more battery cells provided from the transient voltage detection unit. The battery cell may further include an internal short-circuit verification unit that verifies whether an internal short has occurred.

The DC removing unit may include at least one capacitor configured to output an AC component by removing at least one DC component of a positive voltage or a negative voltage of the corresponding battery cell.

The DC removing unit may further include a level shifter that shifts a DC level of at least one of a positive voltage or a negative voltage of the corresponding battery cell to provide the transition to the capacitor.

In order to achieve the above object, the battery monitoring semiconductor integrated circuit according to the present invention is characterized in that the above-described battery monitoring circuit is implemented as a semiconductor integrated circuit.

In the battery monitoring semiconductor integrated circuit according to the present invention, the DC removing unit includes at least one capacitor configured to output an AC component by removing at least one DC component of a positive voltage or a negative voltage of the corresponding battery cell. can do.

In the battery monitoring semiconductor integrated circuit according to the present invention, the DC removing unit may further include a level shifter that shifts a DC level of at least one of a positive voltage or a negative voltage of the corresponding battery cell and provides the transition to the capacitor. can

In the battery monitoring semiconductor integrated circuit according to the present invention, the transient voltage detector includes at least two or more, respectively, corresponding to at least two or more of a plurality of battery cells connected in series, and at least two or more battery cells provided from the transient voltage detector The device may further include an internal short-circuit verification unit that compares each AC component or the transient voltage detection result to verify whether an internal short circuit has occurred in the battery cell.

In order to achieve the above object, the battery device according to the present invention, one or more battery cells connected in series; and a battery monitoring circuit of the present invention configured to monitor a state of the battery cell or control an operation thereof.

The battery monitoring circuit according to the present invention has an effect of preventing a fire or explosion of a battery due to an internal short circuit by detecting a change in an excessive voltage due to an internal short circuit of the battery cell and detecting a defective battery cell.

In addition, the battery monitoring circuit according to the present invention detects a change in a transient voltage caused by an internal short circuit of a battery cell and detects a bad battery cell, so that the reuse determination criterion of the battery cell is determined according to the presence or absence of an internal short circuit of the battery cell. effect that can be presented.

1 is an exemplary view of a conventional battery device.
2 is a circuit diagram of an internal short circuit model of a battery cell for explaining an internal short circuit of the battery cell.
3 is a graph illustrating a change in the drop voltage (V _DROP ) according to the internal short-circuit resistance (R _ISC ) when an internal short circuit occurs in the battery cell.
4 is a block diagram illustrating a battery monitoring circuit and a battery device having the same according to the present invention.
5 is an exemplary diagram illustrating various examples of a transient voltage detection unit according to the present invention.
6 is a diagram illustrating a configuration for verifying whether an internal short circuit has occurred using detection results of a plurality of transient voltage detection units.
7 is a diagram illustrating a specific implementation example of a DC removing unit.

A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. The following detailed description is merely exemplary, and only shows preferred embodiments of the present invention.

Terms related to the present invention will be defined as follows.

A multi-cell battery monitoring circuit (MCBMC) is electrically directly connected to a plurality of series-connected battery cells to measure/monitor/discharge the state of the cells, and to communicate with an external unit. It is a circuit that can At least a portion of this configuration may be implemented as a multi-cell battery monitoring IC (MCBMIC).

A multi-cell battery monitoring IC (MCBMIC, Multi-Cell Battery Monitoring Integrated Circuit) is an IC in which at least a part of a multi-cell battery monitoring circuit is implemented as an integrated circuit. Although there is an advantage that a circuit block inside an IC required for a function required for a plurality of battery cells can be shared, there is a disadvantage that a high voltage process must be used.

Single-Cell Battery Monitoring Circuit (SCBMC) is electrically directly connected to one or more parallel-connected battery cells, and functions to measure/monitor/discharge the state of the cells and communicate with external units. It is a circuit that can be executed. At least a portion of this configuration may be implemented as a single-cell battery monitoring IC (SCBMIC).

A single-cell battery monitoring IC (SCBMIC, Single-Cell Battery Monitoring Integrated Circuit) is an IC in which at least a part of a single-cell battery monitoring circuit is implemented as an integrated circuit. Although there is a disadvantage in that a circuit block inside an IC required for a function required for a plurality of battery cells cannot be shared, there is an advantage in that a general process of a low voltage can be used.

A cell monitoring unit (CMU) is a component that is directly connected to a battery cell to measure/monitor the state of the cell and include all functions of communicating with an external unit. It can be configured with a multi-cell battery monitoring circuit for a multi-cell, or with a single-cell battery monitoring circuit for a single-cell. Typically, EVs and ESSs have a plurality of CMUs.

A battery monitoring unit (BMU) is a set of circuits that communicates with the CMU to collect cell data, transmits a control command required to the connected CMU, and manages the entire battery pack. may be referred to separately from the CMU, or may be referred to as including the CMU. In EV, there is usually one BMU, but in a large-capacity ESS, multiple BMUs may exist.

A battery module is a physical unit configured to include a circuit capable of measuring/monitoring/balancing a plurality of battery cells, and includes a plurality of battery cells and a corresponding cell monitoring unit, but the cell monitoring unit may comprise a multi-cell battery monitoring circuit or may comprise a single-cell battery monitoring circuit. When the cell monitoring unit is configured to include a single-cell battery monitoring circuit, the battery module may be configured to include a plurality of battery units.

A battery pack is a term mainly used in EVs, and includes battery cells, electronic and electrical devices, and all necessary wiring. It may be a configuration including a plurality of battery modules, BMS and various communication wirings (WDC), or a configuration including a plurality of battery units instead of a plurality of battery modules.

A cell measurement wiring (WCM, Wire Harness for Cell Measurement) is a set of conductive wires that electrically connect a CMU and a battery cell in order to measure/monitor the voltage and temperature of the battery cell.

4 is a block diagram illustrating a battery monitoring circuit and a battery device having the same according to the present invention.

Referring to FIG. 4 , the battery cell transient voltage detection circuit according to the present invention corresponds to at least one or more of the one or more battery cells 11 , respectively, and detects one or more transient voltages of the battery cell 11 . It is characterized in that it includes a detection unit (100). In this case, when the transient voltage detection unit 100 detects the transient voltage of the battery cell 11 , it is based on the AC component obtained by removing the DC component of the cell voltage of the corresponding battery cell 11 .

Accordingly, the battery device according to the present invention is configured to monitor the state or control the operation of one or more battery cells 11 and one or more battery cells 11 connected in series to the charging/discharging cable 20, and the above-described transient voltage It may be a configuration including a battery monitoring circuit configured including the transient voltage detection circuit of the battery cell of the present invention having the detection unit 100 .

Here, the battery device of the present invention may be a battery module 10 provided in plurality and managed by the BMU 30 in the battery pack, but a plurality of battery cells 11 are provided in the battery module 10 . It may be a battery pack that is not divided into . The battery device of the present invention is sufficient as long as it has a configuration including one or more battery cells 11 connected in series to the charging/discharging cable 20 and a battery monitoring circuit for monitoring the state of the battery cells or controlling the operation of the battery cells 11 . This is not limited.

The internal short circuit of the battery cell 11 generates an overvoltage due to a small drop voltage (V _DROP ) as the cell internal resistance (Rs) is small and the farther from the thermal runaway threshold as described above, so the internal short circuit is prevented early. The transient voltage detection unit 100 needs a configuration capable of detecting the transient voltage appearing as a very small drop voltage (V _DROP ) so that it can be detected.

To this end, the transient voltage detection unit 100 of the present invention may be configured to detect the transient voltage based on the AC component from which the DC component of the cell voltage of the corresponding battery cell 11 is removed, and further increase the detection sensitivity. A configuration for amplifying an alternating current component may be further added.

As described above, the transient voltage detection unit 100 can detect the transient voltage or internal short circuit of the corresponding battery cell 11 only with the AC component of the cell voltage of the corresponding battery cell 11 , but at least one other battery cell 11 . ), it is also possible to detect the transient voltage of the corresponding battery cell 11 with reference to the detection result of the transient voltage detection unit 100 or to determine whether an internal short circuit occurs.

That is, the transient voltage detection unit 100 of the battery cell transient voltage detection circuit according to the present invention may be provided in at least two or more to correspond to at least two or more battery cells 11 among a plurality of battery cells 11 connected in series. can

In addition to this, the battery cell transient voltage detection circuit according to the present invention compares the alternating current component or the transient voltage detection result of each of the battery cells 11 provided from two or more transient voltage detection units 100 with each other to obtain the battery cell 11 . It may be configured to further include an internal short-circuit verification unit 200 for verifying whether an internal short has occurred.

Since the transient voltage in the battery cell 11 may be caused by switching noise or common mode noise during charging and discharging other than the case due to an internal short circuit, when the transient voltage is detected, it is determined whether this is due to an internal short circuit or other causes In order to do this, it is preferable to compare the AC component or the transient voltage detection result of each of the battery cells 11 with each other.

As described above, since the internal short occurs instantaneously at random in time, it is highly unlikely that the internal short circuit simultaneously occurs in the plurality of battery cells 11 .

Accordingly, the internal short-circuit verification unit 200 of the present invention compares the AC components or the transient voltage detection results of each of the battery cells 11 provided from the two or more transient voltage detection units 100 with each other to obtain a plurality of battery cells 11 . The transient voltage detected at the same time is not due to an internal short circuit, and when the transient voltage is detected in only one battery cell 11 from among the plurality of battery cells 11 in time, the internal short circuit occurs in the corresponding battery cell 11 . As such, the controller 400 may operate to determine. Here, the internal short-circuit verification unit 200 may be configured separately from the control unit 400 , but may be configured to be integrated into the control unit 400 .

In addition, the battery monitoring circuit of the present invention is electrically connected to the cell voltage nodes A1 to An between a plurality of battery cells 11 connected in series, and a multiplexer switch unit ( 310) and an ADC (analog-to-digital converter) 320 that converts the voltage across both ends of the selected specific battery cell 11 into a digital value and provides it to the controller 400 may be further included.

Accordingly, the battery monitoring circuit of the present invention can measure and monitor the cell voltage of the battery cell 11 according to charging or discharging to perform cell balancing or discharging when necessary, as well as detecting a minute transient voltage to the battery. Intermittent and momentary internal short circuits of the cell 11 can be detected.

An exemplary configuration of the transient voltage detection unit 100 of the present invention will be described below.

5 is an exemplary diagram illustrating various examples of the transient voltage detection unit 100 according to the present invention.

Referring to FIG. 5A , each of the transient voltage detection units 100 includes a DC removal unit 110 that provides an AC component by removing the DC component of the voltage between both ends of the corresponding battery cell 11 . can be Here, the DC removing unit 110 may be configured to obtain the AC component by removing the DC component from the voltage across both ends of the battery cell 11 .

In addition to this, the transient voltage detection unit 100 may further include an amplifying unit 120 for amplifying an AC component in order to increase the detection sensitivity for a minute transient voltage due to the characteristics of the transient voltage caused by an internal short circuit. In addition, the comparator 130 may include a comparator 130 that compares the amplified AC component with a predetermined threshold level th and detects whether it is a significant transient voltage.

Referring to FIG. 5B , each of the transient voltage detection units 100 removes a DC component of a positive voltage and a DC component of a negative voltage of the corresponding battery cell 11 to respectively output an AC component. It may be configured to include the removal unit 110 . Here, the DC removing unit 110 removes the DC component with respect to the absolute potential at the positive terminal and the negative terminal of the battery cell 11, respectively, to obtain AC components for the positive voltage and the negative voltage, respectively. can be configuration.

5( a ), the transient voltage detection unit 100 amplifies the difference between each AC component obtained by the DC removal unit 110 in order to increase the detection sensitivity for a minute transient voltage due to the characteristics of the transient voltage caused by an internal short circuit. It may further include an amplifying unit 120 to In this case, the amplifying unit 120 may have a differential amplifier structure that amplifies the difference between AC components. In addition, the comparator 130 may include a comparator 130 that compares the difference between the amplified AC components with a predetermined threshold level th and detects whether the voltage is a significant transient voltage.

Referring to FIG. 5( c ), each of the transient voltage detection units 100 is a DC removal unit that outputs an AC component by removing a DC component of either a positive voltage or a negative voltage of the corresponding battery cell 11 . 110 may be included. Here, the DC removing unit 110 removes the DC component with respect to the absolute potential of any one of the positive terminal and the negative terminal of the battery cell 11 to obtain an AC component for the positive voltage or the negative voltage. It may be a configuration that

5 (a) and 5 (b), the transient voltage detection unit 100, the AC component obtained by the DC removal unit 110 in order to increase the detection sensitivity to a minute transient voltage due to the characteristics of the transient voltage due to an internal short circuit. It may further include an amplifying unit 120 to amplify the . In this case, the amplifying unit 120 may have a structure that amplifies the potential of the AC component with respect to the reference potential. In addition, the comparator 130 may include a comparator 130 that compares the amplified AC component with a predetermined threshold level th and detects whether it is a significant transient voltage.

In particular, unlike FIGS. 5(a) and (b), FIG. 5(c) and FIG. 5(c) for detecting an overvoltage based on the AC component for the absolute potential of either the positive terminal or the negative terminal of the battery cell 11 In the same configuration, when an internal short circuit occurs in a specific battery cell 11, the transient voltage due to the internal short circuit is detected only by the corresponding transient voltage detection unit 100, unlike the structures of FIGS. It may appear in the battery cell 11 connected in series to the positive terminal side of the battery cell 11 , or may appear in the battery cell 11 connected in series to the negative terminal side.

Referring to FIG. 2 , the transient voltage caused by the internal short circuit of the battery cell 11 may be in the form of a notch generated below the potential of the steady state. Therefore, in order to detect the transient voltage generated in the notch form, the predetermined threshold level th compared with the AC component in the comparator 130 is a value lower than the level in the steady state of the AC component at which the transient voltage does not occur. , which is preferably set in consideration of the amplification degree and detection sensitivity of the amplification unit 120 .

In addition, although not shown in the drawings, the transient voltage detection unit 100 of the present invention includes the DC removal unit 110 to control the common mode level of the AC component after the DC component is removed from the DC removal unit 110 . It is also possible to further include a common mode level control unit (not shown) on the output side of the . Here, the common mode level may be set in consideration of an operating voltage of the transient voltage detector 100 , a power supply voltage, a semiconductor process, a noise level, and the like.

6 is a diagram illustrating a configuration for verifying whether an internal short circuit has occurred using the detection results of the plurality of transient voltage detection units 100 .

Referring to FIG. 6 , the battery device of the present invention includes a plurality of battery cells 11 connected in series and at least two or more corresponding to at least two battery cells 11 among the plurality of battery cells 11 , respectively. It may be configured to include the transient voltage detection unit 100 .

At this time, the battery monitoring circuit of the present invention compares the AC components or transient voltage detection results of each of the battery cells 11 provided from the above-described two or more transient voltage detection units 100 with each other to prevent an internal short circuit in the battery cells 11 . It may be configured to further include an internal short-circuit verification unit 200 that verifies whether or not it has occurred.

Through this, the battery monitoring circuit of the present invention determines whether the transient voltage detected in the battery cell 11 is due to an internal short circuit of the battery cell 11 or is due to other causes such as switching noise or common mode noise during charging and discharging. By distinguishing whether or not the internal short circuit event can be verified.

For example, since the internal short occurs instantaneously randomly in time, it may be assumed that the simultaneous occurrence of the internal short in the plurality of battery cells 11 is probabilistically slim.

When the transient voltage detection unit 100 is configured to detect the transient voltage based on the AC component with respect to the voltage across both ends of the specific battery cell 11 as shown in FIGS. 5 (a) and (b), the battery monitoring circuit of the present invention is , by comparing the AC components or transient voltage detection results of each of the battery cells 11 provided from the two or more transient voltage detection units 100 with each other, the transient voltages simultaneously detected in the plurality of battery cells 11 are not due to an internal short circuit. The controller 400 may operate to determine.

In contrast, in the battery monitoring circuit of the present invention, when an overvoltage is detected in only one of the battery cells 11 temporally among the plurality of battery cells 11 , the controller ( 400) may operate to determine.

In addition, the transient voltage detection unit 100 is configured to detect the transient voltage based on the AC component for the absolute potential of any one of the positive terminal or the negative terminal of the specific battery cell 11 as shown in FIG. 5( c ). At this time, the battery monitoring circuit of the present invention compares the AC component or the transient voltage detection result of each of the battery cells 11 provided from the two or more transient voltage detection units 100 with each other, and is applied to the negative side and both sides of the corresponding battery cell 11 . The controller 400 may operate to determine that the transient voltage simultaneously detected in the connected battery cells 11 is not due to an internal short circuit of the corresponding battery cell 11 .

In contrast, in the battery monitoring circuit of the present invention, an overvoltage is detected in the battery cell 11 connected in series to either side of the negative side and both sides of the corresponding battery cell 11, and the battery cell 11 connected in series to the other side is When the overvoltage is not detected, the controller 400 may operate to determine that an internal short circuit has occurred in the corresponding battery cell 11 .

Here, the control unit 400 of the battery monitoring circuit may have a configuration in which the internal short circuit verification unit 200 is integrated, but may have a configuration separate from this, and a specific implementation example is not limited thereto.

7 is a diagram illustrating a specific implementation example of the DC removal unit 110 .

Referring to FIG. 7A , the DC removing unit 110 includes two capacitors for outputting AC components by removing the DC components of the positive and negative voltages of the corresponding battery cells 11 , respectively. can be configuration.

In addition, as corresponding to the configuration of FIG. 5C , the DC removing unit 110 outputs an AC component by removing a DC component of any one of a positive voltage or a negative voltage of the corresponding battery cell 11 . It may be of a configuration including a capacitor.

The positive voltage or the negative voltage of the battery cell 11 is removed by a capacitor having one end connected to the positive terminal or the negative terminal of the battery cell 11, and only the AC component such as the transient voltage is passed to the other end. It may be amplified by the amplifying unit 120 .

The AC component from which the DC component is removed by the capacitor may be configured to have a predetermined DC level by a common mode level controller (not shown) added to the other end of the capacitor.

In addition, referring to FIG. 7B , the DC removing unit 110 includes a level shifter 111 that shifts the DC level of at least one of a positive voltage or a negative voltage of the corresponding battery cell 11 . may include more. The positive voltage or the negative voltage level shifted by the level shifter 111 passes through the capacitor to obtain an AC component from which the DC component of the battery cell 11 is removed.

Through this, since the potential of the battery cell 11 is input to the capacitor after most of the direct current is removed by the level shifter 111, there is an advantage that the capacitor can be designed in a low voltage structure.

The battery monitoring circuit having the above-described transient voltage detection circuit of the battery cell may be implemented using individual devices and may be miniaturized by being implemented as a semiconductor integrated circuit. These battery monitoring semiconductor integrated circuits are SCBMIC (Single-Cell Battery Monitoring Integrated Circuit), DCBMIC (Dual-Cell Battery Monitoring Integrated Circuit) depending on the number of battery cells 11 to be monitored (specifically, the number of battery cells connected in series). , or MCBMIC (Multi-Cell Battery Monitoring Integrated Circuit) may be configured or referred to.

Through the above-described configuration, the battery monitoring circuit according to the present invention detects the defective battery cell 11 by detecting a change in the transient voltage due to the internal short circuit of the battery cell 11, thereby causing the battery fire due to the internal short circuit. Alternatively, there is an effect of preventing an explosion and presenting a criterion for determining the reuse of the battery cell 11 according to the presence or absence of an internal short circuit.

In the foregoing, the present invention has been described and illustrated on the basis of preferred embodiments for illustrating the principles of the present invention, but the present invention is not limited to the construction and operation as shown and described as such. It should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

10, battery module 11: battery cell
12: cell monitoring unit (CMU) 20: charge/discharge cable
30: battery monitoring unit (BMU)
100: transient voltage detection unit 110: DC removal unit
111: level shifter 120: amplification unit
130: comparator 200: internal short-circuit verification unit
310: multiplexer switch unit 320: ADC
400: control unit
A1~An: cell voltage node th: threshold level
VB: cell voltage Rs: cell internal resistance
R _ISC : Internal short circuit resistance SW _ISC : Short circuit switch
VB _ISC : Cell short circuit voltage V _DROP : Drop voltage

Claims (7)

A battery monitoring circuit configured to monitor the status or control operation of one or more battery cells connected in series, the battery monitoring circuit comprising:
an analog-to-digital converter (ADC) for converting the cell voltage of the battery cell into a digital value; and
One or more transient voltage detectors corresponding to at least one or more of the series-connected one or more battery cells, respectively, and detecting the transient voltage of the corresponding battery cell based on the AC component from which the DC component of the cell voltage of the corresponding battery cell is removed including,
Each of the one or more transient voltage detection units,
a direct current removing unit providing an alternating current component by removing the direct current component of the cell voltage of the corresponding battery cell;
an amplifying unit amplifying the AC component; and
and a comparator for detecting a transient voltage by comparing the amplified AC component with a predetermined threshold level,
The transient voltage is a battery monitoring circuit, characterized in that it includes a voltage randomly generated in time during the charging of the battery cell.
delete According to claim 1,
Each of the one or more transient voltage detection units,
a direct current removing unit for outputting alternating current components by removing a direct current component of a positive voltage and a direct current component of a negative voltage of the corresponding battery cell;
an amplifying unit for amplifying a difference between AC components output from the DC removing unit; and
and a comparator for detecting a transient voltage by comparing the difference between the amplified AC components with a predetermined threshold level.
According to claim 1,
Each of the one or more transient voltage detection units,
a direct current removing unit for outputting an alternating current component by removing a direct current component of any one of a positive voltage or a negative voltage of the corresponding battery cell;
an amplifying unit amplifying the AC component; and
and a comparator for detecting a transient voltage by comparing the amplified AC component with a predetermined threshold level.
According to claim 1,
The transient voltage detection unit is provided with at least two and corresponds to at least two or more of the plurality of battery cells connected in series, respectively,
Battery monitoring circuit, characterized in that it further comprises an internal short-circuit verification unit for verifying whether an internal short circuit has occurred in the battery cell by comparing the respective AC components or the transient voltage detection result of at least two or more battery cells provided from the transient voltage detection unit .
5. The method of any one of claims 1, 3 to 4,
The DC removing unit may include at least one capacitor configured to output an AC component by removing at least one DC component of a positive voltage or a negative voltage of the corresponding battery cell.
7. The method of claim 6,
The DC removing unit may further include a level shifter that shifts a DC level of at least one of a positive voltage or a negative voltage of the corresponding battery cell and provides the transition to the capacitor.

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