Battery management system and self-diagnosis method thereof

Abstract

The invention provides a battery management system and a self-diagnosis method thereof. The battery management system comprises a battery management unit, a first switch circuit and a second switch circuit. The first switching circuit and the second switching circuit respectively comprise at least one contactor which is electrically connected between the battery module and the load system. And the control ends of the contactors of the first switching circuit and the second switching circuit are electrically connected with different driving pins of at least one driver respectively so as to respond to the control of the driver to carry out respective closing and opening. According to the battery management system, whether the contactors operate normally or not can be diagnosed automatically, and whether the switches in the contactors have unexpected short circuits or open circuits or not can be diagnosed automatically.

Description

Technical Field

[0001] The present application relates to a battery management system and a self-diagnosis method thereof. Background Art

[0002] As Figure 1 shown, the battery management system 10 of the prior art includes a driver 16 controlled by a battery management unit 14 and a plurality of contactors 12 connected in parallel with each other; each contactor 12 is electrically connected to the same driving pin of the same driver 16 and each includes at least one switch. Although these contactors 12 can avoid abnormal charging and discharging operations caused by an abnormal single switch, the battery management unit 14 cannot diagnose whether each contactor 12 is operating normally, let alone diagnose whether each switch therein has an unexpected short circuit or open circuit. Summary of the Invention

[0003] In order to solve the foregoing technical deficiencies existing in the prior art, the purpose of the present application is to provide a battery management system and a self-diagnosis method thereof.

[0004] The present application provides a battery management system, which includes a battery management unit and a battery switch circuit. The battery switch circuit includes at least one driver and a plurality of contactors. Each contactor is electrically connected between a battery module and a load system and is used to conduct or disconnect the connection between the battery module and the load system. The driver is electrically connected to the battery management unit. The battery switch circuit of the present application further includes a first switch circuit and a second switch circuit, which respectively include at least one contactor; and the control ends of the plurality of contactors corresponding to the first switch circuit and the second switch circuit are respectively electrically connected to different driving pins of at least one driver to perform separate closing and opening in response to the control of the driver.

[0005] In some embodiments, the battery management unit respectively detects the closing or opening of the plurality of contactors through the battery switch circuit.

[0006] In some embodiments, each of the contactors includes a discharge switch and a charge switch connected in series with each other.

[0007] The present application also provides a self-diagnosis method for a battery management system. The battery management system includes a battery management unit, at least one driver, a first switch circuit and a second switch circuit electrically connected to the at least one driver. The first switch circuit and the second switch circuit each include at least one contactor. Each contactor is formed by connecting a discharge switch and a charge switch in series, and includes an input terminal, an output terminal and a detection terminal. The input terminal is electrically connected to a battery module, the output terminal is electrically connected to a load system, and the detection terminal is the series connection point of the discharge switch and the charge switch. The battery management unit is electrically connected to the at least one driver to control the closing or opening of the multiple contactors. The self-diagnosis method includes: when the first switch circuit and the second switch circuit are open, respectively detecting the potential of the detection terminal of each contactor; and when the potential of the detection terminal is not equal to the ground, determining that the discharge switch of the contactor is short-circuited.

[0008] In some embodiments, when the first switch circuit is conducting and the second switch circuit is open, respectively detecting the potentials of the detection terminals of the first switch circuit and the second switch circuit; when the potential of the detection terminal of the first switch circuit is not equal to the potential of the battery module, determining that the discharge switch in the first switch circuit is open; and when the potential of the detection terminal of the second switch circuit is not equal to the ground, determining that the charge switch in the second switch circuit is short-circuited.

[0009] In some embodiments, after the potential of the load system connected to the output terminal is higher than the potential of the battery module connected to the input terminal, the method further includes the steps of: when the first switch circuit is conducting and the second switch circuit is open, detecting the potential of the detection terminal of the first switch circuit; when the potential of the detection terminal of the first switch circuit is not equal to the potential of the output terminal, determining that the charge switch in the first switch circuit is open.

[0010] The present application can turn on and off the first switch circuit and the second switch circuit through the driver, respectively detect whether the circuits of the first switch circuit and the second switch circuit are normal, and whether the switching devices therein are short-circuited or open-circuited, so as to have better safety and reliability. Description of the Drawings

[0011] Figure 1 is a schematic diagram of a battery management system in the prior art;

[0012] Figure 2 is a schematic diagram of the battery management system of the present application;

[0013] Figures 3 to 6 are respectively schematic diagrams of the battery management system of the present application in different embodiments;

[0014] Figure 7 is a flowchart of the self-diagnosis method of the battery management system of the present application;

[0015] Figures 8 to 9Flowchart of the self-diagnosis method in different embodiments of the present application.

[0016] Description of reference numerals: 10 - Battery management system; 12 - Contactor; 14 - Battery management unit; 16 - Driver; 20 - Battery management system; 21 - First switch circuit; 22 - Second switch circuit; 211, 221 - Contactor; 24 - Battery management unit; 26 - Driver; 50 - Battery module; 60 - Load system. Detailed implementation manners

[0017] The present application will be described below based on embodiments, but the present application is not limited to these embodiments. In the following detailed description of the present application, some specific details are described in detail. Those skilled in the art can fully understand the present application without the description of these details. In order to avoid obscuring the essence of the present application, well-known methods, processes, flows, components, and circuits are not described in detail.

[0018] Please refer to Figure 2, which shows a schematic diagram of the battery management system of the present application. The battery management system 20 includes a battery management unit 24 and a battery switch circuit. The battery management unit 24 is a microcontroller or a microprocessor, which can collect data at monitoring points (such as the node voltage of the battery switch circuit), can perform complex operations to ensure charge and discharge control and current balance, etc., can communicate with an external load system 60 to share information or receive commands, and can monitor the health status of the battery pack to detect and handle possible faults or abnormal conditions in a timely manner. The battery switch circuit includes at least one driver 26, a first switch circuit 21 and a second switch circuit 22. The first switch circuit 21 can be understood as the main switch circuit, and the second switch circuit 22 can be understood as the redundant switch circuit. Each of the first switch circuit 21 and the second switch circuit 22 is provided with or includes at least one contactor 211, 221; the difference is that the contactors 211, 221 of the first switch circuit 21 and the second switch circuit 22 are electrically connected to different drive pins of one or more drivers 26. For example, when the number of drivers 26 is one, the contactors 211, 221 of the first switch circuit 21 and the second switch circuit 22 are electrically connected to different drive pins of this driver 26; when the number of drivers 26 is two, the contactors 211, 221 of the first switch circuit 21 and the second switch circuit 22 are respectively electrically connected to one of the drivers 26; or, when the number of drivers 26, contactors 211 and contactors 221 are all two, the two contactors 211 of the first switch circuit 21 are electrically connected to the same or different drive pins of one of the drivers 26, and the two contactors 221 of the second switch circuit 22 are electrically connected to the same or different drive pins of the other driver 26. The driver 26 is used to control the actions of the contactors 211, 221; according to the type of switching device in the contactors 211, 221, the driver 26 can be a gate driver for controlling the turn-off of field effect transistors. In addition, these contactors 211, 221 are also electrically connected between the battery module 50 and the load system 60, so as to be able to conduct or disconnect the connection between the battery module 50 and the load system 60 in response to the control of the driver 26 based on the SPI communication protocol. The load system 60 is, for example, a load module in a vehicle system or an energy system, but is not limited thereto.

[0019] Through the configuration of the battery switch circuit and the driver 26 of the present application, the battery management unit 24 can diagnose the first switch circuit 21 and the second switch circuit 22 separately. For example, the battery management unit 24 can disconnect the contactor 211 in the first switch circuit 21 and turn on the contactor 221 in the second switch circuit 22 through the driver 26, and detect whether the loop between the battery module 50 and the load system 60 is connected; vice versa. In other words, even if the failure point does not occur in the loop or node shared by the first switch circuit 21 and the second switch circuit 22 (such as V1 and V2), but occurs inside the first switch circuit 21 or the second switch circuit 22, the present application can still diagnose the abnormality, thereby avoiding the problem of unexpected disconnection. Moreover, the present application can immediately diagnose the abnormality when any one of the switch circuits is abnormal, rather than diagnosing the abnormality only after all the switch circuits are abnormal.

[0020] In some embodiments, the battery management unit 24 can also diagnose each contactor 211, 221 in the first switch circuit 21 and the second switch circuit 22. For example, when the first switch circuit 21 is provided with a plurality of contactors 211, since these contactors 211 can be electrically connected to different driving pins of the driver 26, the battery management unit 24 can separately close and turn off these contactors 211 through the driver 26, and then diagnose one by one whether any contactor 211 is abnormal.

[0021] Please refer to Figure 3, which shows a schematic diagram of a battery management system in some embodiments. In order to more accurately diagnose abnormal electronic devices, in some embodiments, each contactor 211, 221 includes a discharge switch DMOS (MOS for Discharging) and a charge switch CMOS (MOS for Charging) connected in series with each other. The drain of the discharge switch DMOS is electrically connected to the battery module 50, the drain of the charge switch CMOS is electrically connected to the load system 60, and the source of the discharge switch DMOS and the source of the charge switch CMOS are connected in series with each other and electrically connected to a resistor R grounded at one end. The battery management unit 24 can diagnose the discharge switch DMOS and the charge switch CMOS of a single contactor 211, 221. For example, the battery management unit 24 can detect the voltage drop across the resistor R when the driver 26 is not actuated; if the discharge switch DMOS is short-circuited, the voltage drop will be equal to or approximately equal to the electromotive force of the battery module 50. In some embodiments, each contactor 211, 221 includes two MOS transistors with their drains coupled to each other. According to practical requirements, the MOS transistor can be a high electron mobility NMOS device, a complementary MOS device with low power consumption characteristics, or a double-diffused MOS device or its circuit suitable for high-power applications. In each contactor 211 of the first switch circuit 21, the gates of the two MOS transistors are electrically connected to different driving pins of the same driver 26 or the driving pins of different drivers 26; similarly, the same is true for each contactor 222 of the second switch circuit 22. However, the present application is not limited thereto, please refer to Figure 4 , which shows a schematic diagram of a battery management system in some embodiments. The gates of the two MOS transistors in each contactor 211 of the first switch circuit 21 are electrically connected to the same driving pin of the driver 26, and the gates of the two MOS transistors in each contactor 221 of the second switch circuit 22 are electrically connected to another driving pin of the same driver 26. Such a structure can simplify the circuit configuration and reduce the pin requirements of the driver 26 and the battery management unit 24.

[0022] Please refer to Figure 5 , which shows a schematic diagram of a battery management system in different embodiments. In order to increase product reliability, in some embodiments, the first switch circuit 21 includes a plurality of contactors 211 arranged in parallel, and the second switch circuit 22 includes a plurality of contactors 221 arranged in parallel. The specific structures, device types, connection relationships, etc. of each contactor have been disclosed above, so they will not be elaborated here. In some embodiments, the battery management system 20 may include two drivers 26 electrically connected to the first switch circuit 21 and the second switch circuit 22 respectively to achieve separate control. In this way, not only can the specification requirements of each driver 26 be reduced, but also the battery management system 20 can maintain normal operation when a single driver 26 is abnormal. Please refer to Figure 6, which shows schematic diagrams of the battery management system in different embodiments. The number of drivers 26 increases corresponding to the number of the first switching circuit 21 and the second switching circuit 22, the number of contactors 211 in the first switching circuit 21, the number of contactors 221 in the second switching circuit 22, or the total number of the contactors 211 and 221, so as to increase product reliability. For example, the number of drivers 26 is two, which are electrically connected to the first switching circuit 21 and the second switching circuit 22 respectively to control all the contactors 211 in the first switching circuit 21 and all the contactors 221 in the second switching circuit 22 respectively.

[0023] This application also provides a self-diagnosis method based on the aforementioned battery management system. By controlling the driver 26 by the battery management unit 24 and detecting the voltage of the nodes, the switching devices in each of the contactors 211 and 221 are diagnosed. The specific structures, device types, connection relationships, etc. of the battery management unit 24, the driver 26, the first switching circuit 21 and the second switching circuit 22 have been described above, so they will not be elaborated here. Herein, one end of the contactors 211 and 221 electrically connected to the battery module 50 is defined as the input end, one end of the contactors 211 and 221 electrically connected to the load system 60 is defined as the output end, one end of the contactors 211 and 221 electrically connected to the driver 26 is defined as the control end, and the loop in the contactors 211 and 221 is defined as the detection end. The detection end is, for example, the endpoint where the discharge switch DMOS and the charge switch CMOS are connected in series. The diagnostic items of the battery management unit 24 include but are not limited to: the separate diagnoses of the first switching circuit 21 and the second switching circuit 22 as described above; the separate diagnoses of multiple contactors 211 in the first switching circuit 21 as described above; and the diagnoses of short circuits and open circuits of the discharge switch 211 and / or the charge switch CMOS in all the contactors 211 and 221 as described below.

[0024] Please refer to Figure 7, which shows a flowchart of the self-diagnosis method of the battery management system of the present application. First, it explains how to diagnose whether the discharge switch DMOS is short-circuited. As in step S100, when both the first switch circuit 21 and the second switch circuit 22 are open, the potentials of the detection ends of each contactor 211 and 221 are detected respectively. At this time, it may be that the driver 26 has not been activated by the battery management unit 24, resulting in both the first switch circuit 21 and the second switch circuit 22 being in an open state, or it may be that the driver 26 actively opens the first switch circuit 21 and the second switch circuit 22 in response to the self-diagnosis instruction of the battery management unit 24. As in step S110, when the battery management unit 24 detects that the potential of the detection end of the first switch circuit 21 is approximately equal to the ground potential, it is determined that the discharge switch DMOS of the first switch circuit 21 is not closed, and step S120 is performed; on the contrary, when the aforementioned potential is not approximately equal to the ground potential, for example, approximately equal to or equivalent to the potential of the battery module 50, it is determined that the discharge switch is short-circuited (as in step S112). As in step S120, when the battery management unit 24 detects that the potential of the detection end of the second switch circuit 22 is approximately equal to the ground potential, it is determined that the discharge switch DMOS of the second switch circuit 22 is not closed, and the diagnosis ends; on the contrary, when the aforementioned potential is not approximately equal to the ground potential, for example, approximately equal to or equivalent to the potential of the battery module 50, it is determined that the discharge switch DMOS is short-circuited (as in step S122), and the diagnosis ends. If the discharge switch DMOS of the first switch circuit 21 or the second switch circuit 22 is short-circuited, the battery management unit 24 can take necessary safety measures accordingly or send the diagnosis result to the load system 60.

[0025] In some embodiments, the battery management unit 24 can also diagnose whether the discharge switch DMOS is open-circuited and whether the charge switch CMOS is short-circuited. Please refer to Figure 8 , which continues Figure 7After step S120 and before the end of the diagnosis. As in step S210, in the state where the driver 26 actively turns on the first switch circuit 21 and turns off the second switch circuit 22 in response to the instruction of the battery management unit 24 to perform self-diagnosis, the battery management unit 24 respectively detects the potentials at the detection ends of the first switch circuit 21 and the second switch circuit 22. As in step S220, the battery management unit 24 determines whether the potential at the detection end of the first switch circuit 21 is equal to ground. When the battery management unit 24 detects that the potential at the detection end of the first switch circuit 21 is approximately equal to or equivalent to the potential of the battery module 50, it is determined that the discharge switch DMOS is indeed closed; on the contrary, when the aforementioned potential is approximately equal to ground, it is determined that the discharge switch is open (as in step S222). As in step S230, the battery management unit 24 determines whether the potential at the detection end of the second switch circuit 22 is equal to ground. When the battery management unit 24 detects that the potential at the detection end of the second switch circuit 22 is approximately equal to ground, it is determined that the charging switch CMOS is not short-circuited; on the contrary, when the aforementioned potential is not approximately equal to ground, for example, approximately equal to or equivalent to the potential of the load module 60, it is determined that the charging switch CMOS is short-circuited (as in step S232). Through the above steps, the battery management unit 24 can diagnose whether the discharge switch DMOS of the first switch circuit 21 is open and whether the charging switch CMOS of the second switch circuit 22 is short-circuited.

[0026] Then, as in step S240, in the state where the driver 26 actively turns off the first switch circuit 21 and turns on the second switch circuit 22 in response to the instruction of the battery management unit 24 to perform self-diagnosis, the battery management unit 24 again respectively detects the potentials at the detection ends of the first switch circuit 21 and the second switch circuit 22. As in step S250, the battery management unit 24 determines whether the potential at the detection end of the second switch circuit 22 is equal to ground. When the battery management unit 24 detects that the potential at the detection end of the second switch circuit 22 is approximately equal to or equivalent to the potential of the battery module 50, it is determined that the discharge switch is indeed closed; on the contrary, when the aforementioned potential is approximately equal to ground, it is determined that the discharge switch is open (as in step S252). As in step S260, the battery management unit 24 determines whether the potential at the detection end of the first switch circuit 21 is equal to ground. When the battery management unit 24 detects that the potential at the detection end of the first switch circuit 21 is approximately equal to ground, it is determined that the charging switch CMOS is not short-circuited, and the diagnosis ends; on the contrary, when the aforementioned potential is not equal to ground, for example, approximately equal to or equivalent to the potential of the load module 60, it is determined that the charging switch CMOS is short-circuited (as in step S262), and the diagnosis ends. Through the above steps, the battery management unit 24 can diagnose whether the discharge switch DMOS of the second switch circuit 22 is open and whether the charging switch CMOS of the first switch circuit 21 is short-circuited.

[0027] In some embodiments, the battery management unit 24 can also diagnose whether an open circuit occurs in the charging switch CMOS. Please refer to Figure 9 , which continues Figure 7 after step S120 and before ending the diagnosis. As in step S310, the battery management unit 24 waits for the potential at the output terminal electrically connected to the load system 60 to rise until the potential at the output terminal is slightly higher than that at the input terminal. For example, the load system 60 is a vehicle-mounted system, and the vehicle-mounted system can charge the internal battery electrically connected to the aforementioned output terminal until the potential of the internal battery is slightly higher than that of the aforementioned input terminal; or, the battery management unit 24 is electrically connected to the aforementioned output terminal and raises the potential of the aforementioned output terminal through an internal switching circuit and a voltage stabilizing circuit (not shown in the figure). As in step S320, the battery management unit 24 turns on the first switching circuit 21 and turns off the second switching circuit 22 through the driver 26, and detects the potential at the detection terminal of the first switching circuit 21. As in step S330, the battery management unit 24 determines whether the potential at the aforementioned detection terminal is approximately equal to the potential at the output terminal. When the potential at the aforementioned detection terminal is not equal to the potential at the output terminal, it is determined that an open circuit has occurred in the charging switch CMOS (as in step S332); on the contrary, when the potential at the aforementioned detection terminal is equal to the potential at the output terminal, it is determined that the charging switch CMOS is indeed closed. As in step S340, the battery management unit 24 turns off the first switching circuit 21 and turns on the second switching circuit 22 through the driver 26, and detects the potential at the detection terminal of the second switching circuit 22. As in step S350, the battery management unit 24 determines whether the potential at the aforementioned detection terminal is approximately equal to the potential at the output terminal. When the potential at the aforementioned detection terminal is not equal to the potential at the output terminal, it is determined that an open circuit has occurred in the charging switch CMOS (as in step S352), and the diagnosis ends; on the contrary, when the potential at the aforementioned detection terminal is equal to the potential at the output terminal, it is determined that the charging switch CMOS is indeed closed, and the diagnosis ends. Through the above steps, the battery management unit 24 can respectively diagnose whether an open circuit occurs in the charging switch CMOS of the first switching circuit 21 and the second switching circuit 22.

[0028] The above is only an example to illustrate the preferred embodiments of the present application, and is not intended to limit the scope of implementation. Any simple substitution and equivalent change made according to the claims and the content of the specification of the present application fall within the protection scope of the present application.

Claims

1. A battery management system, which includes a battery management unit and a battery switch circuit. The battery switch circuit includes at least one driver and a plurality of contactors. Each of the contactors is electrically connected between a battery module and a load system and is used to conduct or disconnect the connection between the battery module and the load system. The at least one driver is electrically connected to the battery management unit, and is characterized in that, the battery switch circuit further includes a first switch circuit and a second switch circuit. The first switch circuit and the second switch circuit respectively include at least one of the contactors; control terminals of the plurality of contactors corresponding to the first switch circuit and the second switch circuit are respectively electrically connected to different driving pins of the at least one driver to perform closing and opening in response to the control of the at least one driver.

2. The battery management system according to claim 1, wherein The battery management unit respectively detects the closing or opening of the plurality of contactors through the battery switch circuit.

3. The battery management system according to claim 2, wherein Each of the contactors includes a discharge switch and a charge switch connected in series with each other.

4. The battery management system according to claim 1, characterized in that, each of the contactors includes two MOS transistors with their drains coupled to each other; wherein, in at least one of the contactors of the first switch circuit, the gates of the two MOS transistors are electrically connected to different driving pins of the at least one driver; in at least one of the contactors of the second switch circuit, the gates of the two MOS transistors are electrically connected to different driving pins of the at least one driver.

5. The battery management system according to claim 1, characterized in that, each of the contactors includes two MOS transistors with their drains coupled to each other; wherein, in at least one of the contactors of the first switch circuit, the gates of the two MOS transistors are electrically connected to the same driving pin of the at least one driver; in at least one of the contactors of the second switch circuit, the gates of the two MOS transistors are electrically connected to the same driving pin of the at least one driver.

6. The battery management system according to claim 1, wherein The first switch circuit includes a plurality of the contactors arranged in parallel, and the second switch circuit includes a plurality of the contactors arranged in parallel.

7. The battery management system according to claim 1, wherein The number of the at least one driver corresponds to the number of the plurality of contactors.

8. A self-diagnosis method for a battery management system, the battery management system comprising a battery management unit, at least one driver, and a first switch circuit and a second switch circuit electrically connected to the at least one driver, the first switch circuit and the second switch circuit each comprising at least one contactor, each of the contactors being formed by a discharge switch and a charging switch connected in series, and comprising an input terminal, an output terminal, and a detection terminal, the input terminal being electrically connected to a battery module, the output terminal being electrically connected to a load system, the detection terminal being the series connection point of the discharge switch and the charging switch, the battery management unit being electrically connected to the at least one driver to control the closing or opening of the plurality of contactors, characterized in that, The self-diagnosis method includes the following steps: when the first switch circuit and the second switch circuit are open, respectively detect the potential of the detection terminal of each of the contactors; and when the potential of the detection terminal is not equal to the ground, determine that the discharge switch of the contactor is short-circuited.

9. The self-diagnosis method of the battery management system according to claim 8, wherein The steps further include: when the first switch circuit is conducting and the second switch circuit is open, respectively detect the potentials of the detection terminals of the first switch circuit and the second switch circuit; when the potential of the detection terminal of the first switch circuit is not equal to the potential of the battery module, determine that the discharge switch in the first switch circuit is open; and when the potential of the detection terminal of the second switch circuit is not equal to the ground, determine that the charge switch in the second switch circuit is short-circuited.

10. The self-diagnosis method of the battery management system according to claim 8, characterized in that, After the potential of the load system connected to the output terminal is higher than the potential of the battery module connected to the input terminal, the steps further include: When the first switch circuit is turned on and the second switch circuit is turned off, detect the potential of the detection terminal of the first switch circuit; When the potential of the detection terminal of the first switch circuit is not equal to the potential of the output terminal, determine that the charging switch in the first switch circuit is open.

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