Battery Management System and Its Communication Method

Abstract

A battery management system according to an embodiment of the present invention includes: a main battery management system configured to transmit a wake-up signal to a plurality of slave battery management systems (BMSs); and a plurality of slave battery management systems configured to: transmit status information of battery modules to the main battery management system when receiving the wake-up signal from the main battery management system, wherein at least one of the plurality of slave battery management systems transmits a request signal to the main battery management system and synchronizes a reception period for receiving the wake-up signal from the main battery management system by the plurality of slave battery management systems based on the request signal.

Description

Technical Field

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to Korean Patent Application No. 10-2020-0080556, filed with the Korean Intellectual Property Office on June 30, 2020, the entire disclosure of which is incorporated herein by reference. Technical Field

[0004] The present invention relates to a battery management system for performing wireless communication and a method of wireless communication between battery management systems. Background Art

[0005] Generally, when a vehicle is parked, the power of the main battery management system of the battery management system that performs wireless communication is turned off, and only the slave battery management system installed on the battery module and receiving constant power is turned on.

[0006] If the user starts the vehicle and turns on the power of the main battery management system, the slave battery management system transmits the current state information of the battery module to the main battery management system. However, since it is difficult to predict when the main battery management system will be powered on, the slave battery management system wakes up periodically to operate the receiver and check whether there is a signal transmitted from the main battery management system.

[0007] Since these wake-up signals of the main battery management system are transmitted randomly, the receiver must be operated frequently so that the slave battery management system can quickly identify the signal from the main battery management system. However, when the receiver is operated frequently, the current consumption of the slave battery management system that uses the power of the battery module increases, so the discharge risk of the battery module increases when the vehicle is parked.

[0008] Similarly, when the slave battery management system identifies the signal transmitted from the main battery management system after the vehicle is ignited, there is a trade-off relationship between the wake-up time for the entire battery system to resume normal operation and the sleep current consumed by the slave battery management system when the vehicle is parked. Generally, unless the current consumption of the slave battery management system is improved by hardware, the current consumption of the system is determined according to the wake-up time required by the battery management system. Summary of the Invention

[0009] [Technical Problem]

[0010] The present invention is conceived to solve the above problems, and an object of the present invention is to provide a battery management system and a communication method thereof. After a request signal for requesting a wake-up signal is transmitted from the battery management system to the main battery management system, the reception cycle of the slave battery management system is synchronized, thereby reducing the current consumption of the battery module and effectively using power, and capable of shortening the wake-up time of the battery management system.

[0011] [Technical Solution]

[0012] The battery management system according to an embodiment of the present invention includes: a main battery management system configured to transmit a wake-up signal to a plurality of slave battery management systems (BMS); and a plurality of slave battery management systems configured to: transmit status information of the battery module to the main battery management system when receiving the wake-up signal from the main battery management system, wherein at least one of the plurality of slave battery management systems transmits a request signal to the main battery management system and synchronizes the reception cycle of the plurality of slave battery management systems for receiving the wake-up signal from the main battery management system based on the request signal.

[0013] The communication method of the battery management system according to an embodiment of the present invention includes: transmitting a request signal from at least one of the plurality of slave battery management systems to the main battery management system; synchronizing the reception cycle of the plurality of slave battery management systems for receiving the wake-up signal from the main battery management system based on the request signal; transmitting a wake-up signal to the plurality of slave battery management systems in response to receiving the request signal from the main battery management system; and transmitting the status information of the battery module to the main battery management system based on the plurality of slave battery management systems receiving the wake-up signal from the main battery management system.

[0014] [Advantages of the Present Invention]

[0015] According to the battery management system and the communication method thereof of the present invention, since the reception cycle of the slave battery management system is synchronized after a request signal for requesting a wake-up signal is transmitted from the slave battery management system to the main battery management system, power can be effectively used by reducing the current consumption of the battery module, and the wake-up time of the battery management system can be shortened. Brief Description of the Drawings

[0016] Figure 1 is a schematic diagram showing the operations of the main battery management system and the slave battery management system.

[0017] Figure 2a is a schematic diagram showing the communication operation of a conventional battery management system, Figure 2b is a schematic diagram showing the communication operation of the battery management system according to an embodiment of the present invention.

[0018] Figure 3a andFigure 3b It is a schematic diagram for comparing the power efficiency of a traditional battery management system and a battery management system according to an embodiment of the present invention.

[0019] Figure 4a It is a schematic diagram showing the communication operation of a traditional battery management system, Figure 4b It is a schematic diagram showing the communication operation of a battery management system according to another embodiment of the present invention.

[0020] Figure 5 It is a flowchart showing the communication method of a battery management system according to an embodiment of the present invention.

[0021] Figure 6 It is a flowchart showing the communication method of a battery management system according to another embodiment of the present invention.

[0022] Figure 7 It is a block diagram showing the hardware configuration of a battery management system according to an embodiment of the present invention. Detailed Description of the Embodiments

[0023] Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this document, the same reference numerals are used for the same components in the drawings, and repeated descriptions of the same components are omitted.

[0024] For the various embodiments of the present invention disclosed herein, the purpose of illustrating specific structures or functional descriptions is only to describe the embodiments of the present invention, and the various embodiments of the present invention can be implemented in various forms, and should not be construed as limited to the embodiments described herein.

[0025] Expressions such as "first", "second", "the first" or "the second" used in various embodiments can modify various elements regardless of their order and / or importance, and do not limit the corresponding elements. For example, without departing from the scope of the present invention, the first component can be called the second component, and similarly, the second component can be renamed and called the first component.

[0026] The terms used herein are only for describing specific embodiments and may not be intended to limit the scope of other embodiments. Unless otherwise specified, singular terms may include plural forms.

[0027] All terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by those skilled in the art. Terms defined in a common dictionary can be interpreted as having the same or similar meaning as the meaning in the context of the related art, and unless explicitly defined herein, they are not interpreted as ideal or overly formal meanings. In some cases, even terms defined herein may not be interpreted as excluding embodiments of the present invention.

[0028] Figure 1 It is a schematic diagram showing the operations of the main battery management system and the slave battery management systems.

[0029] A plurality of battery modules 2, 4, and 6 are connected in series or in parallel to the battery pack 1. Each of the battery modules 2, 4, and 6 includes a plurality of battery cells, and slave battery management systems 12, 14, and 16 are respectively arranged. Each of the slave battery management systems 12, 14, and 16 monitors by measuring the states of the plurality of battery modules 2, 4, and 6, such as temperature, voltage, or current, and transmits the monitored information to a superior system, and receives control commands for the battery cells from the superior system to control the connected battery cells.

[0030] The plurality of battery modules 2, 4, and 6 are connected in series or in parallel to form the battery pack 1. The main battery management system 10 is arranged in the battery pack 1. In addition, the main battery management system 10 receives the monitoring information of each battery module from the slave battery management systems 12, 14, and 16 respectively arranged in the battery modules 2, 4, and 6 and transmits the received monitoring information to a superior system, and receives various commands from the superior system and transmits the received various commands to the corresponding slave battery management systems 12, 14, and 16.

[0031] Meanwhile, in the battery management system according to an embodiment of the present invention, the main battery management system 10 may transmit a wake-up signal to the plurality of slave battery management systems 12, 14, and 16 during operation. Specifically, when a request signal is received from any one of the plurality of slave battery management systems 12, 14, and 16, the main battery management system 10 may transmit a wake-up signal to the plurality of slave battery management systems 12, 14, and 16.

[0032] In addition, when a wake-up signal is received from the main battery management system 10, the plurality of slave battery management systems 12, 14, and 16 may transmit the state information of the battery modules to the main battery management system 10. Additionally, at least one of the plurality of slave battery management systems 12, 14, and 16, for example, as a representative slave battery management system, sends a request signal to the main battery management system 10. Based on the corresponding request signal, the plurality of slave battery management systems 12, 14, and 16 may synchronize the reception cycles for receiving the wake-up signal from the main battery management system 10.

[0033] Figure 2a It is a schematic diagram showing the communication operations of a conventional battery management system. Figure 2b It is a schematic diagram showing the communication operations of the battery management system according to an embodiment of the present invention.

[0034] In a conventional battery management system, when the vehicle is parked, as Figure 2aAs shown, while the slave battery management system periodically performs a reception operation, it checks whether a signal is transmitted from the master battery management system. At this time, since the wake-up signal of the master battery management system is transmitted randomly, if the reception time of the slave battery management system is short or the reception cycle is long, the possibility that the slave battery management system successfully receives the signal from the master battery management system decreases. For example, it is preferable that the reception time of the slave battery management system is a time during which the signal from the master battery management system can be received at least twice or more times.

[0035] In addition, in the prior art, since the internal real-time clock (RTC) provided for each slave battery management system is used to calculate the reception cycle, it is difficult to synchronize the reception times of the slave battery management systems. Therefore, in order to successfully receive the signal from the master battery management system in all slave battery management systems, a wake-up command signal must be transmitted from the master battery management system for at least one cycle.

[0036] On the other hand, referring to Figure 2b , regarding the battery management system according to an embodiment of the present invention, one of the plurality of slave battery management systems can transmit a request signal to the master battery management system at the start time point of each reception cycle as a representative slave battery management system (first slave battery management system). In this case, the remaining slave battery management systems (second slave battery management systems) can synchronize the reception cycle based on the request signal. In addition, the representative slave battery management system can perform a wake-up signal reception operation within a predetermined time after completing the transmission of the request signal.

[0037] In the case of the master battery management system, when the vehicle starts, once the reception operation is performed, it waits until a request signal from the slave battery management system selected as a representative is received and the reception is successful, and then a wake-up command signal can be transmitted to the slave battery management system.

[0038] Thus, in the battery management system according to an embodiment of the present invention, since the master battery management system sends a wake-up signal to the slave battery management system after receiving the request signal, the slave battery management system can predict the transmission time of the wake-up signal, and since the reception cycles of the slave battery management systems are synchronized, the wake-up signal from the master battery management system can be successfully received at one time.

[0039] As Figure 2b shown, when the wake-up of both the master battery management system and the slave battery management system in the battery management system according to an embodiment of the present invention is completed, the slave battery management system can transmit data on the state of the battery module (voltage, temperature, etc. of the battery module) to the master battery management system, and the master battery management system can transmit various commands (for example, a state monitoring command, a cell balancing command, a threshold specifying command for abnormality diagnosis, etc.) to the slave battery management system based on the received state information.

[0040] Meanwhile, although it is shown in Figure 2b that one slave battery management system is selected as a representative in the battery management system according to an embodiment of the present invention, multiple slave battery management systems may be selected as the representative slave battery management system when necessary. In addition, although it is shown in Figure 2b that one representative slave battery management system continuously performs a transmission operation, when multiple representative slave battery management systems are selected, each of the multiple representative slave battery management systems alternately performs a transmission operation.

[0041] In addition, when the vehicle is turned off, before the main battery management system is turned off, based on the remaining SoC of the battery module, the selected slave battery management system can determine the order of the targets to become the representative slave battery management system and transmit the order to the remaining slave battery management systems. Therefore, each slave battery management system can act as the representative slave battery management system according to the number of times and the order determined by the remaining SoC.

[0042] However, the representative slave battery management system according to the present invention is determined not only by the SoC, but also in various ways, such as directly set by the user or sequentially selected according to the battery module order. In addition, instead of the representative slave battery management system, at least one slave battery management system can be selected as the representative slave battery management system among the multiple slave battery management systems before the main battery management system is powered off.

[0043] Figure 3a and Figure 3b are schematic diagrams comparing the power efficiency of a conventional battery management system and a battery management system according to an embodiment of the present invention.

[0044] In Figure 3a and Figure 3b , the wake-up signal transmission period of the main battery management system is set to 1 ms, and the reception periods of 12 slave battery management systems are set to 100 ms. In addition, the RF transmission (Tx) current and RF reception (Rx) current of the battery management system are set to 30 mA and 15 mA respectively, and the current consumed by the slave battery management system while the vehicle ignition is turned off is set to 50 μA. However, Figure 3a and Figure 3b the specifications shown are only exemplary, and the present invention is not limited thereto.

[0045] As Figure 3aAs shown, in the communication method of a traditional battery management system, in order to receive the wake-up signal from the main battery management system at least twice, the reception time of the slave battery management system is set to 3 ms. In this case, the current consumption per cycle of the battery management system is 59.82 mAh, and thus, based on a battery pack with a specification of 400 V / 90 kWh / SoC 30%, the number of days for parking can be 47 days of parking.

[0046] On the other hand, in Figure 3b the battery management system according to an embodiment of the present invention as shown, the reception time and transmission time of the representative (#1) slave battery management system are respectively set to 1 ms, and the reception time of the remaining slave battery management systems is set to 2 ms. In this case, the current consumption per cycle of the battery management system is 44.37 mAh, and thus, based on a battery pack with a specification of 400 V / 90 kWh / SoC 30%, the number of days for parking can be 64.8 days of parking. That is to say, compared with the prior art, the battery management system according to an embodiment of the present invention can improve the current consumption per cycle by up to 27.5%, and can also increase the number of days for parking by up to 17.8 days.

[0047] In this way, in the battery management system according to an embodiment of the present invention, since the reception cycle of the slave battery management system is synchronized after the request signal for requesting the wake-up signal is sent from the slave battery management system to the main battery management system, it is possible to effectively use power by reducing the current consumption of the battery module, and to shorten the wake-up time of the battery management system.

[0048] Figure 4a is a schematic diagram showing the communication operation of a traditional battery management system, Figure 4b is a schematic diagram showing the communication operation of a battery management system according to another embodiment of the present invention. Figure 4a and Figure 4b are used to illustrate the case of increasing the reception cycle (for example, twice the size of Figure 3a and Figure 3b ) in order to reduce the current consumption of the battery management system.

[0049] Referring to Figure 4a , when the reception cycle of the slave battery management system in the traditional battery management system is 200 ms, compared with Figure 3a , it has the effect of reducing the average current consumption to 16.45 mAh, but the time required to receive the signal from the main battery management system and wake up cannot be less than the reception cycle at least. In addition, if a specific (#n) slave battery management system misses the wake-up signal from the main battery management system even once due to a signal failure such as noise, then the total wake-up time of the battery management system may be twice the maximum reception cycle in probability.

[0050] On the other hand, asFigure 4b As shown, the battery management system according to an embodiment of the present invention further transmits a request signal to the main battery management system by reducing the transmission period of the request signal in the selected representative slave battery management system by 1 / 2. Therefore, the main battery management system increases the opportunity to receive the request signal from the representative slave battery management system.

[0051] If the representative slave battery management system that performs the transmission / reception operation in the 1 / 2 cycle receives a wake-up signal from the main battery management system, the representative slave battery management system can first copy the received wake-up signal to the request signal and then transmit the request signal to the remaining slave battery management systems.

[0052] In addition, the representative slave battery management system can reduce the reception period of the remaining battery management systems. For example, the reception period of the remaining slave battery management systems can be reduced to the minimum frame unit in which the main battery management system can collect data from the slave battery management system. In this way, even if there is a slave battery management system that fails to receive the wake-up signal, the wake-up signal can be successfully received in a short time.

[0053] In this way, according to Figure 4b the battery management system, the current consumption can be reduced to 15.96 mAh, and even if some slave battery management systems miss the wake-up signal, compared with the conventional battery management system, the total wake-up time of the battery management system can shorten the wake-up time to the reception period + α.

[0054] Figure 5 FIG. is a flowchart showing a communication method of a battery management system according to an embodiment of the present invention.

[0055] Referring to Figure 5 , first, the battery management system (the first slave battery management system) selected as a representative among the plurality of slave battery management systems transmits a request signal to the main battery management system at a preset transmission period (S110). In this case, the representative slave battery management system can be determined before driving the main battery management system based on the remaining SoC of the battery module as described above. In addition, after performing the transmission operation, the representative slave battery management system can switch to the reception operation within a predetermined time to receive a wake-up signal from the main battery management system.

[0056] Then, based on the request signal of the representative slave battery management system, the reception periods of the remaining slave battery management systems (the second slave battery management systems) are synchronized (S120). Therefore, the reception periods of all slave battery management systems for receiving the wake-up signal from the main battery management system can be the same.

[0057] When driving the main battery management system, an operation of receiving a request signal for starting a representative slave battery management system is started (S130). In this case, step S130 may be executed before step S110. That is, after driving the main battery management system and starting the reception operation, the representative slave battery management system may transmit a request signal to the main battery management system to synchronize the reception cycles of the slave battery management systems.

[0058] If the main battery management system does not receive the request signal from the representative slave battery management system (S140) (No), the main battery management system continuously performs the reception operation until it receives the request signal. Meanwhile, when the main battery management system receives the request signal from the representative slave battery management system (Yes), the main battery management system transmits a wake-up signal to a plurality of slave battery management systems (S150).

[0059] In this way, when the wake-up of both the main battery management system and the slave battery management systems in the battery management system according to an embodiment of the present invention is completed, the slave battery management system may transmit data on the state of the battery module (battery module voltage, temperature, etc.) to the main battery management system, and the main battery management system may transmit various commands (for example, a state monitoring command, a cell balancing command, a threshold specifying command for abnormality diagnosis, etc.) to the slave battery management system based on the received state information.

[0060] In this way, according to the communication method of the battery management system according to an embodiment of the present invention, since a request signal is transmitted from the representative slave battery management system to the main battery management system, and the main battery management system transmits a wake-up signal based on these request signals, the time when the main battery management system transmits the wake-up signal can be predicted. In addition, since the reception cycles of the remaining slave battery management systems are synchronized according to the request signal of the representative slave battery management system, all the slave battery management systems can receive the wake-up signal from the main battery management system simultaneously.

[0061] Figure 6 is a flowchart showing a communication method of a battery management system according to another embodiment of the present invention. Figure 6 Steps S250 to S290 in Figure 5 are substantially the same as steps S110 to S150 in

[0062] and thus their detailed descriptions are omitted. Figure 6 Referring to Figure 5 according to another embodiment of the present invention, the battery management system first determines whether the reception cycle of the slave battery management system is equal to or greater than a reference value. In this case, the reference value of the reception cycle may be, for example, 200 ms. At this time, if the reception cycle of the slave battery management system is less than the reference value (No), the process proceeds to step S250, and the same operation as Figure 5 may be performed.

[0063] If the reception period from the battery management system is equal to or greater than a reference value (Yes), the representative slave battery management system (the first slave battery management system) may reduce the transmission period of the request signal (S220). For example, the representative slave battery management system may reduce the transmission period to 1 / 2 or less, thereby increasing the possibility that the master battery management system receives the request signal from the representative slave battery management system.

[0064] Next, after successfully receiving the wake-up signal from the master battery management system, the representative slave battery management system may copy the wake-up signal and transmit the copied wake-up signal to the remaining battery management systems (the second slave battery management systems) (S230).

[0065] In addition, the representative slave battery management system may reduce the reception periods of the remaining slave battery management systems (S240). In this case, the reception periods of the remaining slave battery management systems may be reduced to the minimum frame unit in which the master battery management system can collect data from the slave battery management systems.

[0066] In this way, in the battery management system according to an embodiment of the present invention, the possibility that the remaining slave battery management systems receive the wake-up signal from the master battery management system may be increased through the operations of steps S230 and S240. Therefore, even if the reception of the wake-up signal fails due to a communication failure such as noise among the slave battery management systems, the reception time can be minimized.

[0067] In this way, in the communication method of the battery management system according to an embodiment of the present invention, since the reception periods of the slave battery management systems are synchronized after the slave battery management systems send request signals for requesting wake-up signals to the master battery management system, power can be effectively used by reducing the current consumption of the battery modules, and the wake-up time of the battery management system can be shortened.

[0068] Figure 7 is a block diagram showing the hardware configuration of a battery management system according to an embodiment of the present invention.

[0069] Referring to Figure 7 , the battery management system 700 may include a microcontroller (MCU) 710 for controlling various processes and each configuration; a memory 720 on which an operating system program and various programs (e.g., a battery state measurement program, a signal generation program, a reception synchronization program, etc.) are stored; an input / output interface 730 providing an input interface and an output interface between battery cell modules and / or semiconductor switching elements; and a communication interface 740 capable of communicating with the outside through a wired / wireless communication network. In this way, a computer program according to the present invention may be recorded in the memory 720 and processed by the microcontroller 710, and for example, may be implemented to execute with reference toFigure 2b and Figure 4b modules of the various functions described above

[0070] In the foregoing, even if all components constituting the embodiments of the present invention are described as being combined into one or combined operations, the present invention is not necessarily limited to these embodiments. That is, within the scope of the object of the present invention, all constituent elements can be selectively combined and operated one or more at a time.

[0071] In addition, unless otherwise specified, terms such as "including", "consisting of", or "having" above indicate that the corresponding components may exist, and it should be understood that other components may be further included rather than excluding other components. Unless otherwise defined, all terms, including technical or scientific terms, have the same meaning as commonly understood by those skilled in the art. Common terms such as those defined in a dictionary should be understood to have the same meaning as in the context of the relevant art, and will not be construed as having an ideal or overly formal meaning unless clearly defined in the present invention.

[0072] The above description is only an illustration of the technical concept of the present invention, and those skilled in the art can make various modifications and changes without departing from the essential features of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical concept of the present invention, but are for explanation, and the scope of the technical concept of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the appended claims, and all technical concepts within the equivalent scope thereof should be interpreted as being covered by the present invention.

Claims

1. A battery management system, comprising: A main battery management system configured to transmit a wake-up signal to a plurality of slave battery management systems (BMSs); And A plurality of slave battery management systems configured to: transmit status information of a battery module to the main battery management system when receiving the wake-up signal from the main battery management system, Wherein at least one of the plurality of slave battery management systems transmits a request signal to the main battery management system and synchronizes the reception period of receiving the wake-up signal from the main battery management system by the plurality of slave battery management systems based on the request signal, Wherein when receiving the request signal, the main battery management system transmits the wake-up signal to the plurality of slave battery management systems.

2. The battery management system according to claim 1, wherein, The plurality of slave battery management systems include: A first slave battery management system configured to transmit a request signal to the main battery management system within a preset transmission period; and A second slave battery management system configured to synchronize the reception period based on the request signal of the first slave battery management system.

3. The battery management system according to claim 2, wherein, The first slave battery management system performs a reception operation of the wake-up signal within a predetermined time after the transmission of the request signal is completed.

4. The battery management system according to claim 2, wherein, Based on the reception period of the plurality of slave battery management systems being equal to or greater than a preset reference value, the first slave battery management system reduces the transmission period of the request signal.

5. The battery management system according to claim 4, wherein, Based on the wake-up signal received from the main battery management system, the first slave battery management system transmits the wake-up signal to the second slave battery management system.

6. The battery management system according to claim 4, wherein Based on the wake-up signal received from the main battery management system, the first slave battery management system reduces the reception period of the second slave battery management system.

7. The battery management system according to claim 2, wherein, The first slave battery management system is determined as one of the plurality of slave battery management systems, Wherein the first slave battery management system alternately transmits the request signal to the main battery management system.

8. The battery management system according to claim 2, wherein, The main battery management system or the first slave battery management system determines at least one of the plurality of slave battery management systems as the first slave battery management system before the main battery management system is turned off.

9. The battery management system according to claim 8, wherein, The plurality of slave battery management systems are determined as the first slave battery management system based on the state of charge (SOC) of the battery module.

10. A communication method of a battery management system, the method comprising: Transmitting a request signal from at least one of a plurality of slave battery management systems to a main battery management system; Synchronizing the reception period of receiving a wake-up signal from the main battery management system by the plurality of slave battery management systems based on the request signal; In response to receiving the request signal from the main battery management system, transmitting the wake-up signal to the plurality of slave battery management systems; And When the plurality of slave battery management systems receive the wake-up signal from the main battery management system, transmitting status information of a battery module to the main battery management system.

11. The method according to claim 10, wherein, The plurality of slave battery management systems include: The first slave battery management system, the first slave battery management system being configured to transmit a request signal to the master battery management system within a preset transmission period; and The second slave battery management system, the second slave battery management system being configured to synchronize the reception period based on the request signal of the first slave battery management system.

12. The method according to claim 11, further comprising: The first slave battery management system performs a reception operation of the wake-up signal within a predetermined time after the transmission of the request signal is completed.

13. The method according to claim 11, further comprising: Based on the reception periods of the plurality of slave battery management systems being equal to or greater than a preset reference value, the first slave battery management system reduces the transmission period of the request signal.

Images