Battery system and method for diagnosing a switching device in a battery system

Abstract

The present application provides a battery system and a method for diagnosing a switching device in the battery system. The battery system includes a battery module, N switching devices, and a battery management system. One end of the switching device is connected to the second end of the battery module, and the other end is connected to the second end of an external load and the second end of an external charging device; the battery management module is configured to control N - M of the N switching devices to be disconnected and control M of the switching devices to be turned on when the battery module is in a powered-on state, or in a powered-off state, or in a first discharging state, or in a first charging state; the battery management module is further configured to obtain the non-end voltage of a first switching device among the N - M switching devices and determine whether the first switching device is faulty based on the non-end voltage of the first switching device. The present application can detect whether the switching device is faulty when the battery system is under load.

Description

Technical Field

[0001] The present application relates to battery system diagnostic technology, and more particularly to a battery system and a method for diagnosing a switch device in the battery system. Background Art

[0002] Power batteries are the power sources for large mobile devices, mostly referring to the storage batteries that power electric vehicles, electric trains, electric bicycles, and other devices. The battery system includes components such as the battery module, a battery management system (BMS), and a switch. The switch is controlled by the BMS to shut down, thereby controlling the charge and discharge process of the battery module. The charging process of the battery module is performed by the charger, and the discharge process is performed by the battery module to power the load.

[0003] At present, the commonly used switching device is two field-effect transistors (Metal-Oxide-Semiconductor Field-Effect Transistor, referred to as MOSFET) connected in series, and the source of one MOSFET is directly connected to the source of the other MOSFET. Such a switching device is prone to losing its function of cutting off the current due to DS adhesion of the MOSFET (i.e., the MOSFET is broken down). When the switching device loses its function of cutting off the current, it will cause the battery module to have faults such as overcharging or over-discharging, which will in turn cause damage to the battery module, damage to the load and charger, and even pose a threat to personal safety. Therefore, it is necessary to monitor the status of the switching device to ensure that the function of the switching device is not damaged, thereby ensuring the power safety of the battery system.

[0004] When monitoring the status of a switch device in the existing technology, it is generally necessary to disconnect the battery module from the load and then detect the voltage conditions of the switch device in the "closed" and "open" states. This detection method will cause the load to be interrupted, and in reality, many loads need to be in use at all times and cannot be powered off. Therefore, the status monitoring of the switch device in the existing technology cannot meet the actual demand that the load cannot be powered off. Therefore, how to monitor the status of the switch device of the battery system while the battery system is under load to avoid losses caused by load power outages is currently a problem that needs to be solved urgently. Summary of the Invention

[0005] The present application provides a battery system and a method for diagnosing a switch device in the battery system, for diagnosing the switch device in the battery system without disconnecting the connection between the battery system and an external load.

[0006] On the one hand, the present application provides a battery system, including:

[0007] A battery module, the first end of which is used to connect to the first end of an external load and the first end of an external charging device;

[0008] N switching devices, one end of the switching device is connected to the second end of the battery module, and the other end is connected to the second end of the external load and the second end of the external charging device, where N is an integer greater than 1;

[0009] A battery management module, configured to control N - M of the N switching devices to be disconnected and M of the switching devices to be turned on when the battery module is in a powered - on state, or a powered - off state, or a first discharge state, or a first charge state; when the battery module is in the powered - on state and the powered - off state, the value of M is zero, and when the battery module is in the first discharge state and the first charge state, the value of M is an integer greater than zero;

[0010] The battery management module is further configured to obtain the non - end voltage of the first switching device among the N - M switching devices, and determine whether the first switching device is faulty according to the non - end voltage of the first switching device.

[0011] In one embodiment, the switching device includes:

[0012] A first field - effect transistor, the drain of the first field - effect transistor is connected to the second end of the battery module;

[0013] A second field - effect transistor, the drain of the second field - effect transistor is connected to the second end of the external load and the second end of the external charging device, and the source of the first field - effect transistor is connected to the source of the second field - effect transistor;

[0014] The non - end voltage of the switching device is the source voltage of the first field - effect transistor and the second field - effect transistor.

[0015] In one embodiment, the first discharge state is a state where the battery module is in a discharge state and the discharge current is less than a preset discharge current, and the first charge state is a state where the battery module is in a charge state and the charge current is less than a preset charge current.

[0016] In one embodiment, the battery management module is configured to:

[0017] When the non - end voltage of the first switching device is within a first preset voltage range, determine that the first switching device is fault - free;

[0018] When the non-terminal voltage of the first switching device is outside the first preset voltage range, it is determined that the first switching device is faulty.

[0019] In one embodiment, the battery management module is further configured to receive an external signal sent by an external control device, where the external signal is used to indicate that the battery module is in a powered-on state, or a powered-off state, or a charging state, or a discharging state.

[0020] In one embodiment, it further includes:

[0021] A current sampling circuit, configured to respectively collect the discharge current when the battery module is in a discharging state and the charging current when the battery module is in a charging state.

[0022] In one embodiment, N is equal to 2 and M is equal to 1.

[0023] In one embodiment, the first end of the battery module is the negative electrode of the battery module, and the second end of the battery module is the positive electrode of the battery module;

[0024] Moreover, the first end of the external load is the negative electrode of the external load, and the second end of the external load is the positive electrode of the external load;

[0025] Moreover, the first end of the external charging device is the negative electrode of the external charging device, and the second end of the external charging device is the positive electrode of the external charging device.

[0026] On the other hand, the present application provides a method for diagnosing a switching device in a battery system, which is applied to the battery management module in the battery system according to any one of claims 1-7, and includes:

[0027] When the battery module is in a powered-on state, or a powered-off state, or a first discharging state, or a first charging state, control N-M of the N switching devices to be disconnected, where N is an integer greater than 1; when the battery module is in the powered-on state and the powered-off state, the value of M is zero, and when the battery module is in the first discharging state and the first charging state, the value of M is an integer greater than zero;

[0028] Obtain the non-terminal voltage of the first switching device among the N-M switching devices;

[0029] When the non-terminal voltage is within the first preset voltage range, it is determined that the first switching device is fault-free;

[0030] When the non-terminal voltage is outside the first preset voltage range, it is determined that the first switching device is faulty.

[0031] In one embodiment, the first discharging state is a state in which the battery module is in a discharging state and the discharging current is less than a preset discharging current, and the first charging state is a state in which the battery module is in a charging state and the charging current is less than a preset charging current.

[0032] In one embodiment, it further includes:

[0033] Receiving an external signal sent by an external control device;

[0034] Determining, according to the external signal, that the battery module is in a powered-on state, or a powered-off state, or a discharging state, or a charging state.

[0035] The battery system provided in this application employs N switching devices, where N is an integer greater than 1. When the battery module is in a discharging or charging state, that is, when an external load is put into use or an external charging device is put into use, if it is necessary to detect whether the switching devices are faulty, the battery management module only needs to perform a power-off detection on a part of the N switching devices, and the other part of the switching devices remains in a normal operating state. After the power-off detection of a part of the switching devices is completed, the battery management module can control the first part of the switching devices to be put into use, and perform a power-off detection on the other part of the switching devices that have not been detected.

[0036] Therefore, the battery system provided in this application can detect whether its own switching devices are faulty without disconnecting the connection relationship between the battery system and the external load, solving the problem of forced outage of the load caused by the detection of switching devices in the prior art, and improving the practicality of the battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure.

[0038] Figure 1 A schematic diagram of a battery system provided for an embodiment of this application.

[0039] Figure 2 A schematic diagram of a battery system provided for another embodiment of this application.

[0040] Figure 3 A schematic diagram of a method for diagnosing switching devices in a battery system provided for an embodiment of this application.

[0041] Figure 4 A schematic diagram of a power battery management module provided for an embodiment of this application.

[0042] DESCRIPTION OF THE REFERENCE NUMERALS

[0043] Battery system 10

[0044] Battery module 100

[0045] Switching device 200

[0046] First switching device 210

[0047] First field-effect transistor 211

[0048] Second field-effect transistor 212

[0049] Battery management module 300

[0050] Current sampling circuit 400

[0051] External load 20

[0052] External charging device 30

[0053] Through the above-mentioned drawings, specific embodiments of the present disclosure have been shown, and there will be more detailed descriptions hereinafter. These drawings and the written description are not intended to limit the scope of the concept of the present disclosure in any way, but to illustrate the concept of the present disclosure to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0054] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all the implementation manners consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0055] Power batteries are power sources that provide power for large mobile devices, mostly referring to storage batteries that provide power for electric vehicles, electric trains, electric bicycles, etc. The battery system of a power battery includes battery modules, a battery management system (BATTERY MANAGEMENT SYSTEM, abbreviated as BMS), switching devices, and other components. Among them, the switching device is controlled by the BMS to turn off, so as to control the charging and discharging process of the battery module during the charging and discharging process of the battery module. Among them, the charging process of the battery module is that the charger charges the battery module, and the discharging process of the battery module is that the battery module supplies power to the load.

[0056] Currently, in a 12V battery system, relays, contactors, and Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs for short) are commonly used as switching devices for the 12V battery system. Among them, when using an MOSFET as a switching device, the charging MOSFET and the discharging MOSFET are connected in series to form a "back-to-back" connection. "Back-to-back" means that the source electrode of the charging MOSFET is directly connected to the source electrode of the discharging MOSFET. This switching device using MOSFETs is prone to drain-source (DS) adhesion failure, that is, the MOSFET is broken down. When the MOSFET is broken down, it will cause the BMS to be unable to disconnect the MOSFET, and then lead to serious faults such as overcharging and over-discharging of the battery module. Faults such as overcharging or over-discharging of the battery module will cause damage to the battery module, and then lead to damage to the load and the charger, and even pose a threat to personal safety.

[0057] When the prior art monitors the state of the switching device, generally, it is necessary to disconnect the connection between the battery module and the load, and then detect the voltage conditions of the switching device in the "closed" and "open" states respectively. This detection method will cause the operation of the load to be interrupted, and in reality, many loads need to be in the operating state all the time and do not allow power interruption in the middle. Therefore, the state monitoring of the switching device in the prior art cannot meet the actual requirement that the load cannot be powered off.

[0058] Based on this, the present application provides a battery system and a method for diagnosing a switching device in the battery system, providing N switching devices 200, where N is an integer greater than 1. When a part of the N switching devices 200 are being detected, they are disconnected from the load and the external charging device 30, while another part of the N switching devices 200 remain in the normal operating state. The battery management module 300 (BMS) in the battery system 10 can control which of the switching devices 200 are in the detection state and which are in the normal operating state until all N switching devices 200 are detected. That is, the battery module 100 in the battery system 10 can be normally charged and powered, without being affected by the detection of the switching devices 200, and the load can be in the operating state all the time. It realizes the state monitoring of the switching devices 200 of the battery system 10 under the condition that the battery system 10 is loaded, and avoids the losses caused by the power-off of the load.

[0059] Please refer to Figure 1 , an embodiment of the present application provides a battery system 10, which includes a battery module 100, N switching devices 200, and a battery management module 300, where N is an integer greater than 1.

[0060] The first end of the battery module 100 is connected to the first end of the external load 20 and the first end of the external charging device 30. The second end of the battery module 100 is connected to the second end of the external load 20 through the switching device 200. Similarly, the second end of the battery module 100 is connected to the second end of the external charging device 30 through the switching device 200. That is, one end of the switching device 200 is connected to the second end of the battery module 100, and the other end of the switching device 200 is connected to the second end of the external load 20 and the second end of the external charging device 30.

[0061] Optionally, the first end of the battery module 100 can be the negative electrode of the battery module 100. Correspondingly, the first end of the external load 20 is the negative electrode of the external load 20, and the first end of the external charging device 30 is the negative electrode of the external charging device. The second end of the battery module 100 can be the positive electrode of the battery module 100. Correspondingly, the second end of the external load 20 is the positive electrode of the external load 20, and the second end of the external charging device 30 is the positive electrode of the external charging device.

[0062] When the battery module 100 is in a discharging state, the battery module 100 provides electrical energy for the external load 20. At this time, the battery management module 300 (BMS) controls all or part of the N switching devices 200 to close, so that the battery module 100 outputs current to the external load 20. When the battery module 100 is in a discharging state, all or part of the switching devices 200 can be understood as discharging switching devices.

[0063] When the battery module 100 is in a charging state, the external charging device 30 provides electrical energy for the battery module 100. At this time, the battery management module 300 (BMS) controls all or part of the N switching devices 200 to close, so that the external charging device 30 outputs current to the battery module 100. When the battery module 100 is in a charging state, all or part of the switching devices 200 can be understood as charging switching devices.

[0064] In addition to the discharging state and the charging state, the state of the battery module 100 also includes a power-on state and a power-off state. When the battery module 100 is in the power-on state and the power-off state, all N switching devices 200 should be in an open state. That is, when the battery module 100 is in the power-on state and the power-off state, the battery module 100 is disconnected from both the external load 20 and the external charging device 30.

[0065] The battery management module 300 is used to control the closing or opening of the switching device 200 according to the state of the battery module 100. Optionally, the battery management module 300 can receive an external signal sent by an external control device (not shown in the figure), and the external signal is used to indicate that the battery module 100 is in a powered-on state, or a powered-off state, or a charging state, or a discharging state. The external control device is, for example, a computer, a processor, a single-chip microcomputer, etc., and the external control device can be controlled by a staff member or a user. For example, the external control device can be a touch device on an electric vehicle, and the user can control the generation of the external signal through the touch device and control the sending of the external signal to the battery management module 300. When the battery management module 300 does not receive the external signal sent by the external control device 30, the switching device 200 in the battery system 10 does not need to be detected, and at this time, the N switching devices 200 can all be in a conducting state.

[0066] Furthermore, when the switching device 200 in the battery system 10 needs to be detected, the battery management module 300 is used to control N - M of the N switching devices 200 to open and control M of the switching devices 200 to conduct when the battery module 100 is in a powered-on state, or a powered-off state, or a first discharging state, or a first charging state. Wherein, the first discharging state is a state where the battery module 100 is in a discharging state and the discharging current is less than a preset discharging current, and the first charging state is a state where the battery module 100 is in a charging state and the charging current is less than a preset charging current. Optionally, the preset discharging current can be one-half of the rated discharging current of the battery module 100, and the preset charging current can be one-half of the rated charging current of the battery module 100.

[0067] Optionally, the battery system 10 further includes a current sampling circuit 400. The first input terminal of the current sampling circuit 400 is connected to the battery module 100, and the second input terminal of the current sampling circuit 400 is connected to the external load 20 and the external charging device 30. The current sampling circuit 400 is used to respectively collect the discharging current when the battery module 100 is in a discharging state and the charging current when the battery module 100 is in a charging state.

[0068] When the battery module 100 is in the powered-on state and the powered-off state, the value of M is zero. When the battery module 100 is in the discharging state and the charging state, the value of M is an integer greater than zero. That is, as described above, when the battery module 100 is in the powered-on state and the powered-off state, the battery management module 300 is used to control all N switching devices 200 to open, and no switching device 200 in the N switching devices 200 is closed.

[0069] When the battery management module 300 controls N - M of the N switch devices 200 to be turned off, the battery management module 300 is further configured to obtain the non - end voltage of the first switch device 210 among the N - M switch devices 200, and determine whether the first switch device 210 is faulty according to the non - end voltage of the first switch device 210. The first switch device 210 refers to any one of the N - M switch devices 200. Here, only the first switch device 210 is used to describe the function of the battery management module 300, rather than the battery management module 300 only obtaining the non - end voltage of one switch device among the N - M switch devices 200.

[0070] The battery management module 300 is configured to obtain the non - end voltage of each of the N - M switch devices 200. The non - end voltage refers to the voltage at the non - end of the switch device 200. The ends of the switch device 200 refer to the ends where the switch device 200 is connected to the battery module 100, and the ends connected to the external load 20 and the external charging device 30. The non - end of the switch device 200 does not refer to the voltage in the internal components of the switch device 220, but the voltage between multiple internal components in the switch device 200. For example, if a switch device 220 includes two field - effect transistors connected in series, then the non - end voltage refers to the voltage between the two field - effect transistors.

[0071] In this embodiment, the battery module 100, the external load 20, and the external charging device 30 are all in a working state. Then the end voltage of the first switch device 210 is actually the end voltage of the battery module 100, or the external load 20, or the external charging device 30. The end voltage of the first switch device 210 cannot reflect whether the first switch device 210 is faulty. Therefore, the battery management module 300 needs to determine whether the first switch device 210 is faulty according to the non - end voltage of the first switch device 210.

[0072] When the first switch device 210 is fault - free, since the first switch device 210 is in an off state when being detected, the non - end voltage of the first switch device 210 should be equal to 0V. Therefore, it can be determined whether the first switch device 210 is faulty by judging whether the non - end voltage is 0V. If the non - end voltage of the first switch device 210 is equal to 0V, then the first switch device 210 is fault - free. If the non - end voltage of the first switch is not equal to 0V (including greater than 0V and less than 0V), then the first switch device 210 is faulty.

[0073] However, in practice, there will still be leakage current after the first switching device 210 is turned off. Therefore, the battery management module 300 can be used to determine that the first switching device 210 is fault-free when the non-end voltage of the first switching device 210 is within the first preset voltage range. The battery management module 300 can also be used to determine that the first switching device 210 is faulty when the non-end voltage of the first switching device 210 is outside the first preset voltage range. The first preset voltage range can be set according to actual needs, for example, it can be (-0.2V, 0.2V).

[0074] After detecting whether N-M of the N switching devices 200 are faulty, the battery management module 300 can close the N-M switching devices 200, then open the remaining M switching devices 200, and then detect whether the M switching devices 200 are faulty. That is, when detecting whether the N switching devices 200 are faulty, there must be a switching device 200 that can provide normal charging and discharging of the battery module 100, so that the external load 20 or the external charging device 30 can always be in a working state. Optionally, N is equal to 2 and M is equal to 1. The two switching devices 200 are in a parallel connection relationship. When one of the two switching devices 200 is being detected, the other switching device 200 is in a normal working state.

[0075] The battery system 10 provided in this embodiment can detect the switching device 200 without disconnecting from the load.

[0076] In summary, the battery system 10 provided in this embodiment provides N switching devices 200, where N is an integer greater than 1. When a part of the N switching devices 200 are being detected, they are disconnected from the load and the external charging device 30, while another part of the N switching devices 200 are still in a normal working state. That is, the battery module 100 in the battery system 10, as well as the external load 20 and the external charging device 30, can all work normally without being affected by the detection of the switching device 200. It realizes the status monitoring of the switching device 200 of the battery system 10 under the condition that the battery system 10 is loaded, avoiding situations such as damage to the battery module 100 and load damage caused by load power-off, and also avoiding situations that threaten personal safety due to damage to the battery power supply system, load, etc.

[0077] Please refer to Figure 2 (Schematic diagram of the battery system 10 when N is equal to 2 and M is equal to 1). In an embodiment of the present application, the switching device 200 includes a first field-effect transistor 211 and a second field-effect transistor 212.

[0078] The drain of the first field effect transistor 211 is connected to the second end of the battery module 100, and the drains of the second field effect transistors 212 are both connected to the second ends of the external load 20 and the external charging device 30. The source of the first field effect transistor 211 is connected to the source of the second field effect transistor 212. The second end of the battery module 100 may be the positive electrode of the battery module 100, and the second ends of the external load 20 and the external charging device 30 may be the positive electrodes of the external load 20 and the external charging device 30.

[0079] The specifications and models of the first field effect transistor 211 and the second field effect transistor 212 can both be selected according to actual needs, and are not limited in this application. The specifications and models of the first field effect transistor 211 and the second field effect transistor 212 included in each switching device 200 may be the same or different, and can be specifically selected according to actual needs.

[0080] The non-end voltage of the switching device 200 is the source voltage of the first field effect transistor 211 and the second field effect transistor 212. As Figure 2 shown, points A and B are respectively located at the sources of the two field effect transistors in each switching device 200, and the voltages at points A and B respectively represent the non-end voltage of a switching device 200.

[0081] When the battery module 100 is in the powered-on state or the powered-off state, the battery management module 300 simultaneously collects the voltages at points A and B, and determines whether the switching device 200 corresponding to point A and point B has a fault according to the voltage at point A and the voltage at point B. How to determine whether the switching device 200 is faulty can refer to the above description and will not be elaborated here.

[0082] Please refer to Figure 3 , an embodiment of the present application further provides a method for diagnosing a switching device in a battery system, which is applied to the battery management module 300 (BMS) in the battery system 10 provided in any one of the above embodiments. The method for diagnosing a switching device in the battery system includes:

[0083] S310, when the battery module is in the powered-on state, or, in the powered-off state, or, in the first discharge state, or, in the first charge state, control N - M of the N switching devices to be disconnected, where N is an integer greater than 1; when the battery module is in the powered-on state and the powered-off state, the value of M is zero, and when the battery module is in the first discharge state and the first charge state, the value of M is an integer greater than zero.

[0084] When the battery module 100 is in the discharging state, the battery module 100 provides electrical energy for the external load 20. At this time, the battery management module 300 (BMS) controls all or part of the N switching devices 200 to close, so that the battery module 100 outputs current to the external load 20. When the battery module 100 is in the discharging state, all or part of the switching devices 200 can be understood as discharging switching devices.

[0085] When the battery module 100 is in the charging state, the external charging device 30 provides electrical energy for the battery module 100. At this time, the battery management module 300 (BMS) controls all or part of the N switching devices 200 to close, so that the external charging device 30 outputs current to the battery module 100. When the battery module 100 is in the charging state, all or part of the switching devices 200 can be understood as charging switching devices.

[0086] The first discharging state is the state in which the battery module 100 is in the discharging state and the discharging current is less than the preset discharging current, and the first charging state is the state in which the battery module 100 is in the charging state and the charging current is less than the preset charging current. Optionally, the preset discharging current can be one half of the rated discharging current of the battery module 100, and the preset charging current can be one half of the rated charging current of the battery module 100.

[0087] The charging current and discharging current of the battery module 100 can be collected by the current sampling circuit 400 and then input to the external load 20.

[0088] In addition to the discharging state and the charging state, the state of the battery module 100 also includes the power-on state and the power-off state. When the battery module 100 is in the power-on state and the power-off state, all N switching devices 200 should be in the off state. That is, when the battery module 100 is in the power-on state and the power-off state, the battery module 100 is disconnected from both the external load 20 and the external charging device 30.

[0089] Optionally, the battery management module 300 can also receive an external signal sent by an external control device, and then determine that the battery module 100 is in the power-on state, or the power-off state, or the discharging state, or the charging state according to the external signal.

[0090] The external control device is, for example, a computer, a processor, a single-chip microcomputer, etc. The external control device can be controlled by a staff member or a user. For example, the external control device can be a touch device on an electric vehicle, and the user can control the generation of the external signal through the touch device and control the external signal to be sent to the battery management module 300.

[0091] S320, obtain the non-end voltage of the first switching device among the N-M switching devices.

[0092] The non-end voltage refers to the voltage at the non-end of the switching device 200. The ends of the switching device 200 refer to the ends where the switching device 200 is connected to the battery module 100, as well as the ends connected to the external load 20 and the external charging device 30.

[0093] If the battery module 100, the external load 20, and the external charging device 30 are all in working states, then the end voltages of the first switching device 210 are actually the end voltages of the battery module 100, or the external load 20, or the external charging device 30. The end voltage of the first switching device 210 cannot reflect whether the first switching device 210 is faulty. Therefore, the battery management module 300 needs to determine whether the first switching device 210 is faulty based on the non-end voltage of the first switching device 210.

[0094] S330, when the non-end voltage is within the first preset voltage range, determine that the first switching device is fault-free.

[0095] S340, when the non-end voltage is outside the first preset voltage range, determine that the first switching device is faulty.

[0096] When the first switching device 210 is fault-free, since the first switching device 210 is in an open state during detection, the non-end voltage of the first switching device 210 should be equal to 0V. Therefore, it is possible to determine whether the first switching device 210 is faulty by judging whether the non-end voltage is 0V. If the non-end voltage of the first switching device 210 is equal to 0V, then the first switching device 210 is fault-free. If the non-end voltage of the first switch is not equal to 0V (including greater than 0V and less than 0V), then the first switching device 210 is faulty.

[0097] However, in practice, there will still be leakage current after the first switching device 210 is disconnected. Therefore, the battery management module 300 can be used to determine that the first switching device 210 is fault-free when the non-end voltage of the first switching device 210 is within the first preset voltage range. The battery management module 300 can also be used to determine that the first switching device 210 is faulty when the non-end voltage of the first switching device 210 is outside the first preset voltage range. The first preset voltage range can be set according to actual needs, for example, it can be (-0.2V, 0.2V).

[0098] After detecting whether N - M of the N switch devices 200 are faulty, the battery management module 300 can close the N - M switch devices 200, then open the remaining M switch devices 200, and then detect whether the M switch devices 200 are faulty. That is, when detecting whether the N switch devices 200 are faulty, there must be switch devices 200 that can provide normal charging and discharging of the battery module 100, so that the external load 20 or the external charging device 30 can always be in the working state. Optionally, N is equal to 2, M is equal to 1, and the two switch devices 200 are in a parallel connection relationship. When one of the two switch devices 200 is being detected, the other switch device 200 is in the normal working state.

[0099] The method provided in this embodiment is applied to the battery management module 300 in the battery system 10 provided in the above embodiment. When detecting whether N switch devices 200 are faulty, the battery management module 300 can control a part of the N switch devices 200 to be in the power - off state for detection, and the other part remains in the working state. In this way, it is possible to detect the switch devices 200 under the load state of the battery system 10, avoiding the load power - off caused by the detection of the switch devices 200 and the losses caused by the load power - off.

[0100] Please refer to Figure 4 , in an embodiment of the present application, the battery management module 300 may include:

[0101] A control module 41, configured to control N - M of the N switch devices to be turned off when the battery module is in the power - on state, or in the power - off state, or in the first discharge state, or in the first charge state, where N is an integer greater than 1; when the battery module is in the power - on state and the power - off state, the value of M is zero, and when the battery module is in the first discharge state and the first charge state, the value of M is an integer greater than zero.

[0102] An acquisition module 42, configured to acquire the non - end voltage of the first switch device among the N - M switch devices.

[0103] A processing module 43, configured to determine that the first switch device is fault - free when the non - end voltage is within a first preset voltage range;

[0104] The processing module 43 is further configured to determine that the first switch device is faulty when the non - end voltage is outside the first preset voltage range.

[0105] Among them, the first discharging state is the state in which the battery module is in a discharging state and the discharging current is less than a preset discharging current, and the first charging state is the state in which the battery module is in a charging state and the charging current is less than a preset charging current.

[0106] The processing module 43 is further configured to receive an external signal sent by an external control device; and determine, according to the external signal, that the battery module is in a powered-on state, or a powered-off state, or a discharging state, or a charging state.

[0107] It should be noted that, in this document, the terms "including", "comprising" or any other variant thereof are intended to cover a non-exclusive inclusion, such that a process, method, article or device including a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including such element.

[0108] The serial numbers of the embodiments of the present application above are only for description and do not represent the superiority or inferiority of the embodiments.

[0109] The above are only the preferred embodiments of the present application, and thus do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall equally be included in the patent protection scope of the present application.

Claims

1. A battery system, characterized in that, Comprising: A battery module, the first end of which is used to connect to the first end of an external load and the first end of an external charging device; N switching devices, one end of the switching device is connected to the second end of the battery module, and the other end is connected to the second end of the external load and the second end of the external charging device, where N is an integer greater than 1; A battery management module, which is used to control N - M of the N switching devices to be disconnected and M of the switching devices to be turned on when the battery module is in a powered - on state, or a powered - off state, or a first discharging state, or a first charging state; When the battery module is in the powered - on state and the powered - off state, the value of M is zero, and when the battery module is in the first discharging state and the first charging state, the value of M is an integer greater than zero; The battery management module is further used to obtain the non - end voltage of the first switching device among the N - M switching devices, and determine whether the first switching device is faulty according to the non - end voltage of the first switching device; The switching device includes: A first field - effect transistor, the drain of the first field - effect transistor is connected to the second end of the battery module; A second field - effect transistor, the drain of the second field - effect transistor is connected to the second ends of the external load and the external charging device, and the source of the first field - effect transistor is connected to the source of the second field - effect transistor; The non - end voltage of the switching device is the source voltage of the first field - effect transistor and the second field - effect transistor; The end voltage of the switching device is the end voltage of the battery module, or the external load, or the external charging device.

2. The battery system according to claim 1, characterized in that, The first discharging state is a state where the battery module is in a discharging state and the discharging current is less than a preset discharging current, and the first charging state is a state where the battery module is in a charging state and the charging current is less than a preset charging current.

3. The battery system according to claim 2, characterized in that, The battery management module is used for: When the non - end voltage of the first switching device is within a first preset voltage range, determining that the first switching device is fault - free; When the non - end voltage of the first switching device is outside the first preset voltage range, determining that the first switching device is faulty.

4. The battery system according to claim 2, wherein The battery management module is further used to receive an external signal sent by an external control device, and the external signal is used to indicate that the battery module is in a powered - on state, or a powered - off state, or a charging state, or a discharging state.

5. The battery system according to claim 4, wherein When the battery management module does not receive the external signal sent by the external control device, all the N switching devices are in a conducting state.

6. The battery system according to claim 2, characterized in that, Further comprising: A current sampling circuit, which is used to respectively collect the discharging current when the battery module is in a discharging state and the charging current when the battery module is in a charging state.

7. The battery system according to any one of claims 1-6, characterized in that, N is equal to 2 and M is equal to 1.

8. The battery system according to any one of claims 1-6, characterized in that, The first end of the battery module is the negative electrode of the battery module, and the second end of the battery module is the positive electrode of the battery module; Moreover, the first end of the external load is the negative electrode of the external load, and the second end of the external load is the positive electrode of the external load; Moreover, the first end of the external charging device is the negative electrode of the external charging device, and the second end of the external charging device is the positive electrode of the external charging device.

9. A diagnostic method for a switching device in a battery system, applied to a battery management module in the battery system according to any one of claims 1-8, characterized in that, Including: When the battery module is in the powered-on state, or in the powered-off state, or in the first discharging state, or in the first charging state, controlling N - M of the N switching devices to be turned off, and controlling M of the switching devices to be turned on, where N is an integer greater than 1; when the battery module is in the powered-on state and the powered-off state, the value of M is zero, and when the battery module is in the first discharging state and the first charging state, the value of M is an integer greater than zero; Obtaining the non-end voltage of the first switching device among the N - M switching devices; the non-end voltage of the first switching device is the source voltage of the first field-effect transistor and the second field-effect transistor included therein; When the non-end voltage is within the first preset voltage range, determining that the first switching device is free of faults; When the non-end voltage is outside the first preset voltage range, determining that the first switching device has a fault; The end voltage of the switching device is the end voltage of the battery module, or an external load, or an external charging device.

Images