KR20220129735A - Modular battery management system - Google Patents

Abstract

. Disclosed is a modular battery management system. According to one aspect of the present invention, the modular battery management system includes: a battery pack consisting of a plurality of battery modules to which a plurality of battery cells are connected; a plurality of local management units connected to each of the plurality of battery modules and monitoring a voltage and temperature of each battery module; and a central management unit electrically connected to the plurality of local management units and monitoring a voltage and temperature of the battery pack by using the voltage and temperature of the battery module transmitted from each local management unit.

Description

MODULAR BATTERY MANAGEMENT SYSTEM

The present invention relates to a modular battery management system, and more particularly, a modular battery management for accurately measuring the cell voltage of each of a plurality of battery cells in a battery pack composed of a plurality of battery modules and performing cell balancing. It's about the system.

In general, a large-capacity battery (battery module) capable of generating large-capacity power to drive an energy storage system (ESS), an electric vehicle, a hybrid vehicle, and an electric motorcycle (E-Scooter) can be used.

In particular, with the spread of new and renewable energy, interest in energy storage systems (ESS) that can maximize the efficiency of energy use and storage and quality of electricity as the core of the smart grid is also increasing. . An energy storage system (ESS) may include a large-capacity battery module having a plurality of battery cells (Battery Cells), and a power grid (grid) to supply excess power (surplus energy) when and where it is needed. ), it refers to a system that can optimize the quality and efficiency of power as a storage technology.

A device for more efficiently and stably managing a battery module is a battery management system. The battery management system may be connected to a plurality of battery cells, read a voltage value of each battery cell through an analog to digital converter (A/D), and then control charging or discharging of the battery cells.

When a plurality of battery cells are connected and used as a single battery module, a voltage difference may occur between each battery cell due to chemical difference, physical property difference, or usage period difference of the battery cells constituting the battery module. can Since the lifespan of the battery module may be shortened due to the voltage difference between the battery cells, ultimately, due to performance degradation such as a voltage drop of one single cell (single battery cell), the entire packaged battery module must be replaced with a new battery module. can Therefore, when charging or discharging a large-capacity battery used in an energy storage system (ESS) and an electric vehicle, a cell balancing process by a battery management system to maintain the same voltage of each battery cell may be required.

In addition, the conventional battery management system has a problem in that it is necessary to discard the battery management system (BMS) and manufacture a new one when the cell structure of the battery is changed due to poor compatibility.

The background technology of the present invention is disclosed in Korean Patent Registration No. 10-1571954 (a battery energy storage system capable of emergency operation when an error occurs in a battery rack and an emergency operation method of the battery energy storage system).

The present invention has been devised to improve the above problems, and an object of the present invention is to provide a modular battery management system that does not require a new battery management system even if the cell structure of a battery is changed.

Another object of the present invention is to provide a modular battery management system capable of accurately measuring a cell voltage of each of a plurality of battery cells in a battery pack including a plurality of battery modules and performing cell balancing.

The problem to be solved by the present invention is not limited to the problem(s) mentioned above, and another problem(s) not mentioned will be clearly understood by those skilled in the art from the following description.

A modular battery management system according to an aspect of the present invention includes a battery pack consisting of a plurality of battery modules to which a plurality of battery cells are connected, a plurality of each connected to the plurality of battery modules, and monitoring the voltage and temperature of each battery module. and a central management unit electrically connected to the plurality of local management units to monitor the voltage and temperature of the battery pack by using the voltage and temperature of the battery module transmitted from each local management unit. .

In the present invention, the local management unit includes a voltage monitoring unit measuring an analog cell voltage of each battery cell included in the battery module, a temperature monitoring unit measuring the temperature of the battery module, the voltage monitoring unit, and the temperature monitoring unit A battery monitoring unit that receives an analog cell voltage and a battery module temperature from the, and converts the received analog cell voltage and battery module temperature into a digital cell voltage and a battery module temperature, and digital cells of all battery cells included in the battery module and a local MCU that calculates a battery module voltage by summing voltages and transmits the battery module voltage and battery module temperature to the central management unit.

In the present invention, the voltage monitoring unit includes a discharge switch unit that measures the analog cell voltage of each battery cell and performs voltage balancing of the battery cells, and a filtering unit that filters an excessive voltage generated when a switching element of the discharge switch unit operates can do.

In the present invention, the discharging switch unit includes a switching element that is turned on or off according to a balancing control signal from the battery monitoring unit, a discharge resistor connected to the switching element and the corresponding battery cell, When the device is turned on, the discharge resistor is connected in parallel to the battery cell to discharge the battery cell to perform voltage balancing, and when the switching device is turned off, the discharge resistor is not connected to the battery cell The battery cell may operate normally.

In the present invention, the temperature monitoring unit may include a thermistor that measures the temperature of the battery module, and a first buffer that maintains an output signal of the thermistor or amplifies an output signal of the thermistor.

In the present invention, the battery monitoring unit measures a voltage difference between two adjacent battery cells, compares them with a preset threshold, and when an overvoltage or undervoltage occurs as a result of the comparison, a balancing control signal for performing a voltage balancing operation of the corresponding battery cells. The voltage may be transmitted to the discharge switch unit of the voltage monitoring unit.

In the present invention, the central management unit includes a communication unit for communication with the local management unit, a current measurement unit connected between the battery pack and a load to measure an analog current charged or discharged in the battery pack, and the current measurement unit. It may include a central MCU that converts the analog current measured by the unit into a digital current and calculates the voltage of the battery pack by summing the voltages of the battery modules respectively received from the plurality of local management units through the communication unit.

In the present invention, the communication unit may include a Serial Communication Interface (SCI) signal line and a level shifter for matching a voltage level between the local management unit and the central management unit.

In the present invention, the current measuring unit may include a shunt resistor connected between the battery pack and the load, and an operational amplifier for amplifying a voltage measured through both ends of the shunt resistor.

The modular battery management system according to an embodiment of the present invention distinguishes the local management unit from the central management unit and modularizes the local management unit, thereby providing high compatibility, even if the cell structure of the battery is changed. There is an effect that it is not necessary to create a new BMS.

The modular battery management system according to an embodiment of the present invention can increase the lifespan of a battery module by accurately measuring the cell voltage of each of a plurality of battery cells in a battery pack composed of a plurality of battery modules and performing cell balancing. can

On the other hand, the effects of the present invention are not limited to the above-mentioned effects, and various effects may be included within the range apparent to those skilled in the art from the description below.

1 is a view for explaining a modular battery management system according to an embodiment of the present invention.
2 is a diagram for explaining a local management unit according to an embodiment of the present invention.
FIG. 3 is a view for explaining the discharge switch unit shown in FIG. 2 .
FIG. 4 is a view for explaining the filtering unit shown in FIG. 2 .
FIG. 5 is a view for explaining the interface unit shown in FIG. 2 .
6 is a view for explaining a central management unit according to an embodiment of the present invention.
FIG. 7 is a view for explaining the communication unit shown in FIG. 6 .
FIG. 8 is a view for explaining the current measuring unit shown in FIG. 6 .

Hereinafter, a modular battery management system according to an embodiment of the present invention will be described with reference to the accompanying drawings. In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of explanation.

In addition, the terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to intentions or customs of users and operators. Therefore, definitions of these terms should be made based on the content throughout this specification.

Further, implementations described herein may be implemented as, for example, a method or process, an apparatus, a software program, a data stream, or a signal. Although discussed only in the context of a single form of implementation (eg, discussed only as a method), implementations of the discussed features may also be implemented in other forms (eg, as an apparatus or program). The apparatus may be implemented in suitable hardware, software and firmware, and the like. A method may be implemented in an apparatus such as, for example, a processor, which generally refers to a computer, a microprocessor, a processing device, including an integrated circuit or programmable logic device, or the like. Processors also include communication devices such as computers, cell phones, portable/personal digital assistants ("PDA") and other devices that facilitate communication of information between end-users.

1 is a view for explaining a modular battery management system according to an embodiment of the present invention.

Referring to Figure 1, the modular battery management system according to an embodiment of the present invention is a battery pack 100, local management units (200a, 200b, ..., 200n, hereinafter referred to as 200) connected to the battery pack 100. referred to) and a central management unit 300 .

The battery pack 100 may be configured through serial-parallel connection of a plurality of battery modules 110a, 110b, ... 110n, hereinafter referred to as 110 . That is, the battery module 110 may be configured through serial/parallel connection of the battery cells, and the battery pack 100 may be configured through the serial connection of the battery modules 110 . A different number of battery modules 110 may be included in one battery pack 100 depending on the application environment as to the number of battery modules 110 included in the battery pack 100 . The battery cell may be one selected from the group consisting of a lithium ion battery, a lithium polymer battery, and the like, but the present invention is not limited thereto.

The battery pack 100 may be charged by receiving power or may be discharged by supplying electric energy charged in the battery pack 100 to a load. That is, the plurality of battery modules 110 stores power in the plurality of battery modules 110 according to a charge command of the corresponding local management unit 200 or the central management unit 300 , and stores power in the plurality of batteries according to a discharge command. Power stored in the module 110 may be discharged.

Each of the plurality of local management units 200 may be electrically connected to a corresponding battery module 110 to sense a voltage and temperature of a battery cell, and manage charging, discharging, and cell balancing of the battery cell. Of course, one local management unit 200 may manage one battery module 110 .

The plurality of local management units 200 may be respectively connected to the plurality of battery modules 110 included in the battery pack 100 to control charging and discharging of each of the plurality of battery modules 110 .

The local management unit 200 may be connected to the battery module 110 and perform a function of controlling the corresponding battery module 110 . The control function of the local management unit 200 may include charge/discharge control, balancing control, switching, electrical characteristic value measurement and monitoring, error indication, on/off control, etc. of the battery cells included in the battery module 110 . In addition, various electrical and electronic control functions known at the time of filing of the present invention may be included in the control function of the local management unit 200 .

Algorithms for battery cell voltage measurement, battery module 110 temperature measurement, and battery cell balancing may be loaded in the local management unit 200 .

The central management unit 300 is electrically connected to the plurality of local management units 200 , and uses the voltage and temperature of the battery module 110 transmitted from each local management unit 200 to control the entire battery pack 100 . It can manage charging, discharging and/or balancing packs, etc.

The central management unit 300 may receive the battery module voltage data transmitted from each local management unit 200 to monitor the battery module voltage and temperature.

The central management unit 300 may be equipped with an algorithm for monitoring battery pack voltage and measuring battery pack current.

Figure 2 is a view for explaining the local management unit according to an embodiment of the present invention, Figure 3 is a view for explaining the discharge switch unit shown in Figure 2, Figure 4 is a view for explaining the filtering unit shown in Figure 2 , FIG. 5 is a view for explaining the interface unit shown in FIG. 2 .

Referring to FIG. 2 , the local management unit 200 according to an embodiment of the present invention includes a voltage monitoring unit 210 , a temperature monitoring unit 220 , a battery monitoring unit 230 , an interface unit 240 , and a local MCU. 250 may be included.

The voltage monitoring unit 210 may measure an analog cell voltage of each battery cell of the battery module 110 .

The voltage monitoring unit 210 may include a discharge switch unit 212 and a filtering unit 216 connected to each battery cell.

The discharge switch unit 212 may be connected to the battery cells, measure an analog cell voltage of each battery cell, and transmit the measured analog cell voltage to the battery monitoring unit 230 through the filtering unit 216 .

Also, the discharge switch unit 212 may discharge the battery cells. That is, when a specific battery cell voltage is higher than that of another battery cell, the discharge switch unit 212 may be used to lower the voltage of a battery cell having a high voltage.

As shown in FIG. 3 , the discharge switch unit 212 may include a field effect transistor (FET) and a discharge resistor (R).

A field effect transistor (FET) may be connected to limit the flow of current from the battery cell. Here, the field effect transistor is a switching element, and the technical scope of the present invention is not limited thereto, and an electric element performing other types of switching functions may be used. The FET may be implemented as, for example, a MOSFET.

When there is a difference in voltage of each battery cell included in the battery module 110 , the discharge switch unit 212 may perform a voltage balancing operation of the battery cell. To this end, the discharge switch unit 212 may be configured in such a way that a current path is formed at both ends of each battery cell, and an FET is provided in the current path. In this case, the battery monitoring unit 230 may lower or increase the voltage of each battery cell by controlling the FET, thereby balancing the voltage of several battery cells. That is, the battery monitoring unit 230 monitors the voltages of each battery cell and, when there is a difference in the voltages of the battery cells, transmits a balancing control signal for performing a voltage balancing operation of the corresponding battery cells to the discharge switch unit 212 . can The discharge switch unit 212 receiving the balancing control signal may turn on the FET to perform voltage balancing of the battery cells.

For example, the difference between the n-th battery cell voltage C(n) and the (n+1)-th battery cell voltage C(n+1) is compared with a preset threshold value, and as a result of the comparison, the overvoltage or undervoltage In this case, the battery monitoring unit 230 performs a balancing control signal to perform a balancing operation between the nth battery cell voltage C(n) and the (n+1)th battery cell voltage C(n+1). (S(n)) may be transmitted to the discharge switch unit 212 . The FET of the discharge switch unit 212 receiving the balancing control signal may be turned on to perform voltage balancing between the two battery cells.

In addition, the discharge switch unit 212 may include a discharge resistor (R). In this case, the discharging switch unit 212 connects a specific battery cell to the discharging resistor R, so that power of the specific battery cell is consumed by the discharging resistor R, thereby performing a balancing operation to lower the voltage of the corresponding battery cell. can be done

The FET can serve as a switch that connects and disconnects the discharge resistor (R) to each battery cell. When the FET is in the ON state, a discharge resistor is connected in parallel to the corresponding battery cell to supply power to the discharge resistor (R) connected in parallel to discharge the corresponding cell. On the other hand, when the FET is in the OFF state, the discharge resistor R is not connected to the corresponding battery cell, and thus the corresponding battery cell may operate normally.

Also, the discharge switch unit 212 may include a Zener diode. The Zener diode may serve to remove noise generated during the on/off operation of the FET and maintain a source-gate voltage required for the FET operation.

On the other hand, small transient voltages occur when the FET is turned on or off, which can reduce the accuracy of analog-to-digital (ADC) conversions in electrical circuits. Accordingly, by connecting the filtering unit 216 to the discharge switch, it is possible to filter the transient voltage and reduce an error during ADC conversion.

The filtering unit 216 may filter the transient voltage generated during the FET operation of the discharge switch unit 212 . The filtering unit 216 may be implemented as an RC filtering circuit as shown in FIG. 4 . That is, the filtering unit 216 may include a series resistor and a shunt capacitor.

The filtering unit 216 may transmit the battery cell voltage from which the transient voltage is filtered to the battery monitoring unit 230 .

The temperature monitoring unit 220 may measure the temperature of the battery module 110 . For example, the temperature monitoring unit 220 may measure an external temperature and/or an internal temperature of the battery module 110 . In addition, the temperature monitoring unit 220 may measure the temperature of various points inside the battery module 110 to determine the temperature of the battery module 110 in more detail for each part. Meanwhile, the temperature monitoring unit 220 may transmit the measured temperature information of the battery module 110 to the battery monitoring unit 230 .

The temperature monitoring unit 220 may include a thermistor 222 and a first buffer 226 .

The thermistor 222 may measure the temperature of the battery module 110 . In this case, the thermistor 222 may be implemented as, for example, a negative temperature coefficient (NTC) thermistor (Negative Temperature Coefficient-thermic).

The NTC thermistor 222 operates to decrease resistance when the temperature of the battery module 110 rises, and the thermistor voltage is proportional to the temperature, so the temperature of the battery module 110 can be calculated as the voltage of the thermistor 222 . The first buffer 226 may be used to supply a preset constant voltage (eg, 3.065V) to the NTC thermistor 222 .

The first buffer 226 may serve to maintain the output signal of the thermistor 222 or amplify the output signal of the thermistor 222 . That is, the output signal of the thermistor 222 may be lost (lost). Accordingly, by storing the output signal of the thermistor 222, the first buffer 226 can prevent loss (loss) of the output signal of the thermistor 222, thereby maintaining the output signal of the thermistor 222. have. In addition, since the output signal of the thermistor 222 is to change the voltage into temperature, the output signal of the thermistor 222 may be weak. Accordingly, the first buffer 226 may amplify the output signal of the thermistor 222 .

The battery monitoring unit 230 receives the analog cell voltage and the battery module temperature from the voltage monitoring unit 210 and the temperature monitoring unit 220 , and converts the received analog cell voltage and the battery module temperature into the digital cell voltage and the battery module temperature. can be converted

Also, the battery monitoring unit 230 may control the discharge switch unit 212 to perform a battery protection operation. If abnormal conditions such as overdischarge, overcharge, short circuit and overcurrent occur in the battery module 110, the battery monitoring unit 230 controls the discharge switch unit 212 to protect the BMS circuit and the battery from the abnormal condition. have.

That is, the battery monitoring unit 230 monitors the voltage of each battery cell, compares the voltage difference between the two battery cells with a preset threshold, and when an overvoltage or undervoltage occurs as a result of the comparison, the voltage balancing operation of the corresponding battery cell is performed. A balancing control signal to be performed may be transmitted to the discharge switch unit 212 . Here, the threshold value may include an overvoltage threshold value for determining whether the overvoltage is present and a low voltage threshold value for determining whether the voltage is undervoltage.

For example, if the voltage difference between the nth battery cell and the (n+1)th battery cell is equal to or greater than an overvoltage threshold (eg, 35mV), the battery monitoring unit 230 determines that the n+1th battery cell is the nth battery cell. The FET of the n+1th battery cell may be turned on by determining that it has a higher voltage. In addition, if the voltage difference between the n-th battery cell and the (n+1)-th battery cell is less than the low voltage threshold (eg, -35 mV), the battery monitoring unit 230 determines that the n-th battery cell is higher than the n+1-th battery cell. The FET of the nth battery cell may be turned on by determining that it has a high voltage.

The battery monitoring unit 230 may transmit the digital cell voltage and the battery module temperature to the local MCU 250 through the interface unit 240 .

The interface unit 240 may include an SPI signal line 242 and a second buffer (buffer circuits 2 and 246 ). That is, the battery monitoring unit 230 and the local MCU 250 communicate through SPI, and the SPI is a clock (SCLK), chip select (CS), master output slave input (MOSI), and master input slave output (MISO). can be configured. When the SPI signal line 242 communicates, the second buffer 246 may be used to prevent influence from the surroundings.

The second buffer 246 may be used to prevent loss of a signal from the SPI signal line 242 . The second buffer 246 may include, for example, LT1719 and NC7WZ, LT1719 may serve as a buffer for MISO signals, and NC7WZ may serve as buffers for SCLK, CS, and MOSI signals.

The local MCU 250 may monitor the battery cell voltage, calculate the battery module voltage as the sum of all battery cell voltages, and then transmit the battery module voltage and temperature to the central management unit 300 through serial communication.

The local MCU 250 may set and control a monitoring mode, a monitoring speed, the number of cells to be monitored per battery module, a discharge resistor connection configuration, an overvoltage/undervoltage threshold, and the like of the battery monitoring unit 230 .

The local MCU 250 may transmit various commands, such as a battery cell voltage, a battery module temperature, and a specific battery cell discharge degree, to the battery monitoring unit 230 and obtain corresponding information.

6 is a view for explaining a central management unit according to an embodiment of the present invention, FIG. 7 is a view for explaining the communication unit shown in FIG. 6, FIG. 8 is a view for explaining the current measuring unit shown in FIG. to be.

Referring to FIG. 6 , the central management unit 300 may include a communication unit 310 , a central MCU 320 , and a current measurement unit 330 .

The communication unit 310 is a configuration for connecting the local management unit 200 and the central management unit 300 , and may include an SCI signal line 312 and a level shifter 314 as shown in FIG. 7 .

Unlike SPI, SCI (Serial Communication Interface) only has a line from the local management unit 200 to (RX) of the central management unit 300 and a line from the central management unit 300 to (TX) of the local management unit 200 only. have. The two lines may be directly connected to the SCI RX and TX ports of the central MCU 320 .

Meanwhile, the local MCU 250 and the central MCU 320 have different voltage levels. Accordingly, the level shifter 314 may be used to ensure stable communication between two MCUs having different voltage levels.

The level shifter 314 may enable communication between the central management unit 300 (3.3V) and the local management unit 200 (5V) having different voltage levels. The level shifter 314 may use an N-channel logic level enhancement mode field effect transistor that lowers the 5V signal to 3.3V and raises the 3.3V signal to 5V. The level shifter 314 converts 3.3V and 5V serial communication interface signals between the central management unit 300 and the local management unit 200 , and the SCI exchanges data between the central management unit 300 and the local management unit 200 . It is possible to provide a communication interface that enables

The current measuring unit 330 may be connected between the battery pack 100 and the charger/load, measure analog charge/discharge current, and convert it into a digital voltage.

The current measuring unit 330 is electrically connected between the battery pack 100 and the load (charger) to detect a current input (charged) and/or an output (discharge) current to the battery pack 100 . have. The current measuring unit 330 may be any one selected from the group consisting of a Hall sensor, a shunt resistor, and the like, but the present invention is not limited thereto.

The analog voltage measured by the current measuring unit 330 may be transmitted to the ADC pin of the central MCU 320 .

The current measuring unit 330 may include a shunt resistor 332 and an operational amplifier 336 as shown in FIG. 8 .

Since the resistance value of the shunt resistor 332 is very low as 2 mΩ, the charge/discharge current passing through the shunt resistor 332 may induce a voltage proportional to the current. Accordingly, the charge/discharge current may be measured by measuring the voltage across the shunt resistor 332 .

However, a small voltage reading reduces the accuracy of the current measurement, so an operational amplifier 336 can be connected through a shunt resistor 332 to solve this problem. The operational amplifier 336 may amplify the voltage of the shunt resistor 332 with a gain of 100 mV/A.

The central MCU 320 may convert the analog current measured by the current measurement unit 330 into a digital current and monitor the battery pack voltage, current, and temperature.

The central MCU 320 may monitor both the battery pack current and voltage. In this case, the current may be collected through the battery current measuring unit 330 , and the battery pack voltage may be obtained by summing all battery module voltages. The battery module voltage is transmitted from the local MCU 250 to the central MCU 320 through serial communication, but the voltage levels of the local MCU 250 and the central MCU 320 are different. Therefore, the level shifter 314 may be used to ensure stable communication between two MCUs having different voltage levels.

As described above, the modular battery management system according to an embodiment of the present invention distinguishes the local management unit from the central management unit, and by modularizing the local management unit, it is possible to provide high compatibility, and thereby the cell of the battery. Even if the structure is changed, there is an effect that it is not necessary to create a new BMS.

The modular battery management system according to an embodiment of the present invention can increase the lifespan of a battery module by accurately measuring the cell voltage of each of a plurality of battery cells in a battery pack composed of a plurality of battery modules and performing cell balancing. can

Although the present invention has been described with reference to the embodiment shown in the drawings, this is merely exemplary, and those of ordinary skill in the art to which various modifications and equivalent other embodiments are possible. will understand

Therefore, the true technical protection scope of the present invention should be defined by the following claims.

100: battery rack
110: battery module
200: local management unit
210: voltage monitoring unit
220: temperature monitoring unit
230: battery monitoring unit
240: interface unit
250: local MCU
300: central management unit
310: communication department
320: central MCU
330: current measuring unit

Claims (9)

a battery pack comprising a plurality of battery modules to which a plurality of battery cells are connected;
a plurality of local management units respectively connected to the plurality of battery modules and monitoring voltages and temperatures of each battery module; and
A central management unit electrically connected to the plurality of local management units to monitor the voltage and temperature of the battery pack by using the voltage and temperature of the battery module transmitted from each local management unit
A modular battery management system comprising a.
According to claim 1,
The local management unit,
a voltage monitoring unit measuring an analog cell voltage of each battery cell included in the battery module;
a temperature monitoring unit for measuring the temperature of the battery module;
a battery monitoring unit receiving an analog cell voltage and a battery module temperature from the voltage monitoring unit and the temperature monitoring unit, and converting the received analog cell voltage and battery module temperature into a digital cell voltage and a battery module temperature; and
and a local MCU (main control unit) for calculating a battery module voltage by summing digital cell voltages of all battery cells included in the battery module, and transmitting the battery module voltage and battery module temperature to the central management unit A modular battery management system with
3. The method of claim 2,
The voltage monitoring unit,
a discharge switch unit for measuring an analog cell voltage of each battery cell and balancing the voltage of the battery cell; and
The modular battery management system, characterized in that it comprises a filtering unit for filtering the transient voltage generated during the operation of the switching element of the discharge switch unit.
4. The method of claim 3,
The discharge switch unit,
a switching element turned on or off according to a balancing control signal from the battery monitoring unit; and
A discharging resistor connected to the switching element and the corresponding battery cell,
When the switching element is turned on, the discharge resistor is connected in parallel to the battery cell to discharge the battery cell to perform voltage balancing,
When the switching element is turned off, the battery cell is not connected to the discharge resistor is a modular battery management system, characterized in that the normal operation of the battery cell.
3. The method of claim 2,
The temperature monitoring unit,
a thermistor for measuring the temperature of the battery module; and
A modular battery management system comprising a first buffer for maintaining the output signal of the thermistor or amplifying the output signal of the thermistor.
3. The method of claim 2,
The battery monitoring unit,
The voltage difference between two adjacent battery cells is measured and compared with a preset threshold, and when an overvoltage or undervoltage occurs as a result of the comparison, a balancing control signal for performing a voltage balancing operation of the corresponding battery cell is transmitted to the discharge switch unit of the voltage monitoring unit A modular battery management system, characterized in that.
The method of claim 1,
The central management unit,
a communication unit for communication with the local management unit;
a current measuring unit connected between the battery pack and a load to measure an analog current charged or discharged in the battery pack; and
A central MCU that converts the analog current measured by the current measurement unit into a digital current and calculates the voltage of the battery pack by summing the voltages of the battery modules received from a plurality of local management units through the communication unit. Featuring a modular battery management system.
8. The method of claim 7,
The communication unit,
SCI (Serial Communication Interface) signal line; and
and a level shifter for matching the voltage level between the local management unit and the central management unit.
8. The method of claim 7,
The current measuring unit,
a shunt resistor coupled between the battery pack and the load; and
and an operational amplifier for amplifying the voltage measured through both ends of the shunt resistor.

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