A battery management unit and energy storage system
By employing a design with four optocouplers and a controller in the battery management unit, CAN address allocation can be automatically completed regardless of the wiring sequence, solving the address allocation problem caused by wiring errors and improving wiring efficiency and address allocation reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HONGHE ELECTRONICS (HANGZHOU) CO LTD
- Filing Date
- 2026-04-13
- Publication Date
- 2026-07-10
AI Technical Summary
In the prior art, wiring errors in the battery management unit lead to low wiring efficiency, and slave address allocation is prone to errors, making it impossible to assign the correct CAN address to the slave.
The structure design employs four optocouplers and a controller, ensuring that the first and second interfaces of the battery management unit are identical. Regardless of how the upper and lower battery management units are wired, address allocation can be achieved. Through the conduction of the optocouplers and the control of the controller, CAN address allocation is completed automatically.
It improves wiring efficiency, avoids address allocation problems caused by wiring errors, ensures the reliability and uniqueness of address allocation, reduces wiring time, and ensures accurate allocation of slave addresses.
Smart Images
Figure CN122371390A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of communication control technology, specifically to a battery management unit and energy storage system. Background Technology
[0002] The energy storage system includes a Battery Control Unit (BCU) and multiple Battery Management Units (BMUs) to manage multiple battery clusters. The BCU acts as the master controller, and the BMUs act as slave controllers. The slave controller closest to the master controller is the first-level slave controller, and all slave controllers after the first-level slave controller are subordinate slave controllers.
[0003] In related technologies, wiring between master and slave controllers, and between slave controllers themselves, requires specific methods. If wiring errors occur, the correct CAN address cannot be assigned to the slave controller. This causes inconvenience in field operations, resulting in low wiring efficiency and frequent errors in slave controller address assignment. Summary of the Invention
[0004] In view of this, this application provides a battery management unit and energy storage system that can improve wiring efficiency and address allocation reliability.
[0005] To solve the above problems, the technical solution provided in this application is as follows: In a first aspect of this application, a battery management unit is provided, comprising: a first optocoupler, a second optocoupler, a third optocoupler, a fourth optocoupler, and a controller; The first input terminal of the first optocoupler is connected to the power supply, the second input terminal of the first optocoupler is connected to the power supply and the first output terminal of the second optocoupler, the first output terminal of the first optocoupler is connected to the power supply and the controller, and the second output terminal of the first optocoupler is grounded. The first input terminal of the second optocoupler is connected to the power supply, the second input terminal of the second optocoupler is connected to the controller, and the second output terminal of the second optocoupler is grounded. The first input terminal of the third optocoupler is connected to the power supply, the second input terminal of the third optocoupler is connected to the power supply and the first output terminal of the fourth optocoupler, the first output terminal of the third optocoupler is connected to the power supply and the controller, and the second output terminal of the third optocoupler is grounded. The first input terminal of the fourth optocoupler is connected to the power supply, the second input terminal of the fourth optocoupler is connected to the controller, and the second output terminal of the fourth optocoupler is grounded. The first output terminal of the second optocoupler is used to connect to other battery management units or battery control units, and the first output terminal of the fourth optocoupler is used to connect to other battery management units.
[0006] In one possible implementation, when the battery management unit is a master slave controller, the first output terminal of the second optocoupler is used to connect to the battery control unit. The battery control unit is used to send a low-level enable signal to the first output terminal of the second optocoupler, so that the first optocoupler is turned on and the first output terminal of the first optocoupler is pulled low. The controller is used to request an initial CAN address from the battery control unit via the CAN bus when it detects that the first input terminal of the first optocoupler is low.
[0007] In one possible implementation, the controller is also configured to, upon receiving the initial CAN address, control the second input terminal of the fourth optocoupler to a low level, thereby turning on the fourth optocoupler and pulling the first output terminal of the fourth optocoupler to a low level, sending a low-level enable signal to other battery management units.
[0008] In one possible implementation, when the battery management unit is not a primary slave controller, the first output terminal of the second optocoupler is used to connect to other battery management units. The controller is used to detect that the first input terminal of the first optocoupler is low, obtain the incrementing CAN address according to the CAN address of the previous slave controller, and control the second input terminal of the fourth optocoupler to be low, so that the fourth optocoupler is turned on. The first output terminal of the fourth optocoupler is low, triggering other connected battery management units.
[0009] In one possible implementation, the controller is also used to control the second input terminal of the fourth optocoupler to be low after completing the CAN address allocation, so that the fourth optocoupler is turned on; if the first output terminal of the third optocoupler is detected to be low, then it is confirmed that the next-level slave controller has completed the CAN address allocation.
[0010] In one possible implementation, the controller is also configured to report a fault to the battery control unit via the CAN bus when it detects that the first output of the first optocoupler is low and CAN address allocation has failed, or when the first output of the third optocoupler is not low.
[0011] One possible implementation also includes a resistor; The first input terminal, the second input terminal, and the third input terminal of the first optocoupler are connected to the power supply through the first resistor, the second resistor, and the third resistor, respectively. The first input terminal of the second optocoupler is connected to the power supply through the fourth resistor; The first, second, and third input terminals of the third optocoupler are connected to the power supply via the fifth, sixth, and seventh resistors, respectively. The first input terminal of the fourth optocoupler is connected to the power supply through the eighth resistor.
[0012] One possible implementation also includes a diode; The first resistor is connected to the negative terminal of the first diode, and the positive terminal of the first diode is connected to the power supply; the second resistor is connected to the negative terminal of the second diode, and the positive terminal of the second diode is connected to the power supply. The fifth resistor is connected to the negative terminal of the third diode, and the positive terminal of the third diode is connected to the power supply; the sixth resistor is connected to the negative terminal of the fourth diode, and the positive terminal of the fourth diode is connected to the power supply.
[0013] In a second aspect of this application, an energy storage system is provided, including a battery control unit and a plurality of battery management units; The battery control unit acts as the master controller, and multiple battery management units act as slave controllers; among the multiple slave controllers, one is the primary slave controller, and the rest are non-primary slave controllers.
[0014] In one possible implementation, when the master controller receives a fault report from the battery control unit, it sends a low-level enable signal to the first output terminal of the second optocoupler of the master slave controller to turn on the first optocoupler and pull the first output terminal of the first optocoupler to a low level.
[0015] The battery management unit provided in this application includes four optocouplers and a controller. The first and second interfaces of the battery management unit have identical structures, ensuring address allocation regardless of how the first and second interfaces of the upper and lower level battery management units are wired. Therefore, during field wiring, there is no need to consider the upper and lower level addresses of the battery management unit to allocate the interface wiring sequence, saving wiring time, improving wiring efficiency, avoiding wiring errors that could lead to address allocation failures, and ensuring the reliability of address allocation. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the connection relationship of a battery management unit in related technologies; Figure 2 This is a schematic diagram of a battery management unit in related technologies; Figure 3 A schematic diagram of a battery management unit provided in an embodiment of this application; Figure 4 This is a schematic diagram illustrating the connection relationship of a battery management unit as provided in an embodiment of this application. Detailed Implementation
[0017] See Figure 1 The figure is a schematic diagram of the connection relationship of a battery management unit in related technologies.
[0018] like Figure 1 As shown, in the relevant technology, multiple slave controllers are connected in series through the first interface DIO1 and the second interface DIO2. The DO interface of the master control node can only be connected to the first interface DIO1 of the first slave controller, and the second interface DIO2 of the first slave controller can only be connected to the first interface DIO1 of the lower slave controller, and so on.
[0019] See Figure 2The figure is a schematic diagram of a battery management unit in the related technology.
[0020] The following will continue to combine Figure 1 Briefly introduce the address allocation principle of slave controller.
[0021] When the master control unit (BCU) outputs a high level to the first interface DIO1 of the primary slave controller, the first optocoupler PC1 of the primary slave controller is turned on, causing the first detection pin DI1 to go low. The controller allocates an address to the primary slave controller based on the low level of the first detection pin DI1 and outputs a high level to the first control pin DO1. This turns on the second optocoupler PC2 of the primary slave controller, causing the second interface DIO2 of the primary slave controller to output a low level. Since the second interface DIO2 of the primary slave controller is connected to the first interface DIO1 of the lower-level slave controller, the first interface DIO1 of the lower-level slave controller goes low, turning on the first optocoupler PC1 of the lower-level slave controller, thus ultimately achieving address allocation for all slave controllers.
[0022] However, due to the battery management unit adopting Figure 2 The structure shown requires each slave controller to depend on... Figure 1 The sequential series connection shown in the diagram enables address allocation, which places high demands on field wiring, results in low wiring efficiency, and is prone to errors in slave address allocation. To address these issues, embodiments of this application provide a battery management unit and an energy storage system.
[0023] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the embodiments of this application will be further described in detail below with reference to the accompanying drawings and specific implementation methods.
[0024] See Figure 3 The figure is a schematic diagram of a battery management unit provided in an embodiment of this application.
[0025] The battery management unit provided in this application embodiment includes: a first optocoupler PC1, a second optocoupler PC2, a third optocoupler PC3, a fourth optocoupler PC4, and a controller 100.
[0026] The first input terminal of the first optocoupler PC1 is connected to the power supply SYS+, the second input terminal of the first optocoupler PC1 is connected to the power supply SYS+, and the first output terminal of the second optocoupler PC2 is connected to the power supply SYS+ and the controller 100. The second output terminal of the first optocoupler PC1 is grounded. The first output terminal of the second optocoupler PC2 serves as the first interface DIO1.
[0027] The first input terminal of the second optocoupler PC2 is connected to the power supply SYS+, the second input terminal DO1 of the second optocoupler PC2 is connected to the controller 100, and the second output terminal of the second optocoupler PC2 is grounded.
[0028] The first input terminal of the third optocoupler PC3 is connected to the power supply SYS+. The second input terminal of the third optocoupler PC3 is connected to the power supply SYS+ and the first output terminal of the fourth optocoupler PC4. The first output terminal DI2 of the third optocoupler PC3 is connected to the power supply SYS+ and the controller 100. The second output terminal of the third optocoupler PC3 is grounded. The first output terminal of the fourth optocoupler PC4 serves as the second interface DIO2.
[0029] The first input terminal of the fourth optocoupler PC4 is connected to the power supply SYS+, the second input terminal DO2 of the fourth optocoupler PC4 is connected to the controller 100, and the second output terminal of the fourth optocoupler PC4 is grounded.
[0030] The first output terminal of the second optocoupler PC2 is used to connect to other battery management units or battery control units, and the first output terminal of the fourth optocoupler PC4 is used to connect to other battery management units.
[0031] Since the structures of the first optocoupler PC1 and the second optocoupler PC2 corresponding to the first interface DIO1 are exactly the same as the structures of the third optocoupler PC3 and the fourth optocoupler PC4 corresponding to the second interface DIO2, the first interface and the second interface do not need to be distinguished in the battery management unit provided in this application embodiment.
[0032] The battery management unit provided in this application includes four optocouplers and a controller. The first and second interfaces of the battery management unit have identical structures. Regardless of how the first and second interfaces of the upper and lower level battery management units are wired, address allocation can still be achieved. Therefore, during field wiring, there is no need to consider the upper and lower level addresses of the battery management unit to allocate the wiring sequence of the interfaces, saving wiring time, improving wiring efficiency, avoiding the problem of address allocation failure due to wiring errors, and ensuring the reliability of address allocation.
[0033] See Figure 4 This figure is a schematic diagram of the connection relationship of a battery management unit provided in an embodiment of this application.
[0034] To enable those skilled in the art to understand the address allocation logic of the battery management unit provided in the embodiments of this application, the following description is provided in conjunction with specific embodiments.
[0035] In one possible implementation, when the battery management unit provided in this application is a master slave controller, the first output terminal of the second optocoupler PC2 is used to connect to the battery control unit.
[0036] The battery control unit is used to send a low-level enable signal to the first output terminal of the second optocoupler PC2, so that the first optocoupler PC1 is turned on and the first output terminal of the first optocoupler PC1 is pulled low.
[0037] The controller 100 is used to request an initial CAN address from the battery control unit via the CAN bus when it detects that the first input terminal of the first optocoupler PC1 is low.
[0038] After the energy storage system is powered on, the controller 100 outputs a high level to all slave controllers, while the first optocoupler PC1, the second optocoupler PC2, the third optocoupler PC3, and the fourth optocoupler PC4 are all turned off. During address allocation, the battery control unit first allocates an address to the primary slave controller. Specifically, the battery control unit sends a low-level enable signal to the first output terminal of the second optocoupler PC2, turning on the first optocoupler PC1 and pulling its first output terminal low. When the controller 100 detects that the first input terminal of the first optocoupler PC1 is low, it determines that the battery management unit is the primary slave controller and requests an initial CAN address from the battery control unit via the CAN bus. The battery control unit sends the CAN address to the primary slave controller, which then claims the CAN address. Subsequently, the battery control unit polls, and the primary slave controller responds according to the allocated address. After the address is fixed, it sends an acknowledgment message back to the battery control unit, thus completing the address allocation for the primary slave controller.
[0039] In one possible implementation, the battery management unit and controller 100 provided in this application embodiment are further configured to, after receiving the initial CAN address, control the second input terminal DO2 of the fourth optocoupler PC4 to a low level, so that the fourth optocoupler PC4 is turned on, and the first output terminal of the fourth optocoupler PC4 is pulled to a low level, so as to send a low-level enable signal to other battery management units.
[0040] The above embodiment takes the battery control unit connected to the first interface of the primary slave controller as an example. Since the structure of the first interface and the second interface are exactly the same, the above control logic can also be implemented when the battery control unit is connected to the second interface of the mobile phone slave controller, which will not be described in detail here.
[0041] In one possible implementation, when the battery management unit provided in this application is a non-primary slave controller, the first output terminal of the second optocoupler PC2 is used to connect to other battery management units.
[0042] The controller 100 is used to detect that the first input terminal of the first optocoupler PC1 is low, obtain the incrementing CAN address according to the CAN address of the previous slave controller, and control the second input terminal of the fourth optocoupler PC4 to be low, so that the fourth optocoupler PC4 is turned on and the first output terminal of the fourth optocoupler PC4 is low, triggering other connected battery management units.
[0043] This application does not specifically limit the connection method between the primary slave controller and the non-primary slave controller. The second interface DIO2 of the primary slave controller can be connected to the first interface DIO1 of the non-primary slave controller, or the second interface DIO2 of the primary slave controller can be connected to the second interface DIO2 of the non-primary slave controller. The following explanation will first use the example of connecting the second interface DIO2 of the primary slave controller to the first interface DIO1 of the non-primary slave controller.
[0044] When the controller 100 detects that the first input terminal of the first optocoupler PC1 (not the primary slave controller) is low, it obtains the incrementing CAN address according to the CAN address of the previous slave controller, confirms the address via the CAN bus, and controls the second input terminal of the fourth optocoupler PC4 (not the primary slave controller) to be low, thus turning on the fourth optocoupler PC4. The first output terminal of the fourth optocoupler PC4 (not the primary slave controller) is low, triggering other connected battery management units, thereby realizing address allocation for the non-primary slave controller.
[0045] The following explanation uses the example of connecting the second interface DIO2 of the primary slave controller to the second interface DIO2 of a non-primary slave controller. When the controller 100 detects that the first input terminal of the third optocoupler PC3 of the non-primary slave controller is low, it obtains the incrementing CAN address according to the CAN address of the previous slave controller, confirms the CAN address through the CAN bus feedback, and controls the second input terminal of the second optocoupler PC2 of the non-primary slave controller to be low, thus turning on the second optocoupler PC2 of the non-primary slave controller. The first output terminal of the second optocoupler PC2 of the non-primary slave controller is low, triggering other connected battery management units, thereby realizing the address allocation for the non-primary slave controller.
[0046] The address allocation logic between the superior non-primary slave controller and the subordinate non-primary slave controller is the same as the address allocation logic between the primary slave controller and the non-primary slave controller, and will not be repeated here.
[0047] The battery management unit provided in this application embodiment has identical structures for its first and second interfaces. Regardless of whether the second interface of the primary slave controller is connected to the first interface of a non-primary slave controller, or vice versa, address allocation for the non-primary slave controller can be achieved. That is, the battery management unit provided in this application embodiment can automatically and sequentially allocate slave controller addresses without considering the connection order of the interfaces, improving field work efficiency and reducing slave controller address allocation errors caused by wiring mistakes.
[0048] In one possible implementation, the battery management unit and controller 100 provided in this application embodiment are further configured to, after completing the CAN address allocation, control the second input terminal DO2 of the fourth optocoupler PC4 to be low, and turn on the fourth optocoupler PC4; if the first output terminal DI2 of the third optocoupler PC3 is detected to be low, then confirm that the next-level slave controller has completed the CAN address allocation.
[0049] Specifically, after the next-level slave controller completes the CAN address allocation, the controller 100 controls the second input terminal DO2 of the fourth optocoupler PC4 of the next-level slave controller to output a low level, and transmits the low-level signal to the first output terminal DI2 of the third optocoupler PC3 of the same level slave controller. Therefore, when the controller 100 detects that the first output terminal DI2 of the third optocoupler PC3 of the same level slave controller is low, it means that it has received the feedback signal from the next-level slave controller, and can confirm that the next-level slave controller has completed the CAN address allocation.
[0050] The battery management unit provided in this application embodiment allows the controller to confirm that the lower-level slave controller has completed CAN address allocation by detecting the slave controller at the same level. This forms a closed-loop confirmation process from issuing enable to allocating address and then to returning for confirmation, reducing problems such as CAN address allocation omissions and CAN address conflicts caused by signal loss.
[0051] In one possible implementation, the battery management unit, controller 100 provided in this application embodiment, is further configured to report a fault to the battery control unit via the CAN bus when the first output terminal DI1 of the first optocoupler PC1 is detected to be low and CAN address allocation fails, or when the first output terminal DI2 of the third optocoupler PC3 is not detected to be low.
[0052] The battery management unit provided in this application embodiment can report an anomaly to the battery control unit via the CAN bus when the CAN address allocation at this level fails or when no feedback signal is received from the next level slave controller. This allows the battery control unit to reassign addresses to all battery management units, ensuring the uniqueness and reliability of the CAN address allocation for each battery management unit.
[0053] In one possible implementation, the battery management unit provided in this application embodiment further includes a resistor.
[0054] See also Figure 3The first input terminal, second input terminal, and first output terminal of the first optocoupler PC1 are connected to the power supply SYS+ through the first resistor R1, the second resistor R2, and the third resistor R3, respectively; the first input terminal of the second optocoupler PC2 is connected to the power supply SYS+ through the fourth resistor R4. The first input terminal, second input terminal, and first output terminal of the third optocoupler PC3 are connected to the power supply SYS+ through the fifth resistor R5, the sixth resistor R6, and the seventh resistor R7, respectively; the first input terminal of the fourth optocoupler PC4 is connected to the power supply SYS+ through the eighth resistor R8.
[0055] This application does not specifically limit the specific resistance values of the first to eighth resistors. They can be selected according to the actual situation. The first to eighth resistors can achieve the functions of current limiting protection, level conversion and anti-interference, so that the battery management unit can accurately identify high and low level signals.
[0056] In one possible implementation, the battery management unit provided in this application embodiment further includes a diode.
[0057] See also Figure 3 The first resistor R1 is connected to the negative terminal of the first diode D1, and the positive terminal of the first diode D1 is connected to the power supply SYS+; the second resistor R2 is connected to the negative terminal of the second diode D2, and the positive terminal of the second diode D2 is connected to the power supply SYS+.
[0058] The fifth resistor R5 is connected to the negative terminal of the third diode D3, and the positive terminal of the third diode D3 is connected to the power supply SYS+; the sixth resistor R6 is connected to the negative terminal of the fourth diode D4, and the positive terminal of the fourth diode D4 is connected to the power supply SYS+.
[0059] Based on the battery management unit provided in the above embodiments, this application also provides an energy storage system. The energy storage system provided in this application includes a battery control unit and any of the battery management units provided in the above embodiments.
[0060] Among them, the battery control unit acts as the master controller, and multiple battery management units act as slave controllers; among the multiple slave controllers, one is the primary slave controller, and the rest are non-primary slave controllers.
[0061] The energy storage system provided in this application embodiment can achieve address allocation regardless of how the interfaces of the upper and lower level battery management units are wired. Therefore, when wiring in the field, there is no need to consider the upper and lower level addresses of the battery management units to allocate the wiring sequence of the interfaces, which can save wiring time, improve wiring efficiency, avoid the problem of address allocation failure due to wiring errors, and ensure the reliability of address allocation.
[0062] In one possible implementation, the energy storage system provided in this application embodiment, when the master controller receives a fault report from the battery control unit, sends a low-level enable signal to the first output terminal of the second optocoupler of the first slave controller to turn on the first optocoupler, and the first output terminal of the first optocoupler is pulled low.
[0063] The energy storage system provided in this application embodiment can reassign addresses to all battery management units when a CAN address allocation failure occurs in the battery management unit, thus ensuring the uniqueness and reliability of the CAN address allocation for each battery management unit.
[0064] The controller provided in this application embodiment may include software to implement the control methods described above. Alternatively, the controller provided in this application embodiment may include hardware to implement the control methods described above. Or, the controller provided in this application embodiment may include both software and hardware, using a combination of software and hardware to execute the control methods described above.
[0065] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0066] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A battery management unit, characterized in that, include: First optocoupler, second optocoupler, third optocoupler, fourth optocoupler and controller; The first input terminal of the first optocoupler is connected to the power supply, the second input terminal of the first optocoupler is connected to the power supply and the first output terminal of the second optocoupler, the first output terminal of the first optocoupler is connected to the power supply and the controller, and the second output terminal of the first optocoupler is grounded. The first input terminal of the second optocoupler is connected to the power supply, the second input terminal of the second optocoupler is connected to the controller, and the second output terminal of the second optocoupler is grounded. The first input terminal of the third optocoupler is connected to the power supply, the second input terminal of the third optocoupler is connected to the power supply and the first output terminal of the fourth optocoupler, the first output terminal of the third optocoupler is connected to the power supply and the controller, and the second output terminal of the third optocoupler is grounded. The first input terminal of the fourth optocoupler is connected to the power supply, the second input terminal of the fourth optocoupler is connected to the controller, and the second output terminal of the fourth optocoupler is grounded. The first output terminal of the second optocoupler is used to connect to other battery management units or battery control units, and the first output terminal of the fourth optocoupler is used to connect to other battery management units.
2. The battery management unit according to claim 1, characterized in that, When the battery management unit is a master-slave controller, the first output terminal of the second optocoupler is used to connect to the battery control unit. The battery control unit is used to send a low-level enable signal to the first output terminal of the second optocoupler to turn on the first optocoupler and pull the first output terminal of the first optocoupler to a low level. The controller is configured to request an initial CAN address from the battery control unit via the CAN bus when it detects that the first input terminal of the first optocoupler is at a low level.
3. The battery management unit according to claim 2, characterized in that, The controller is also configured to, upon receiving the initial CAN address, control the second input terminal of the fourth optocoupler to be at a low level, thereby turning on the fourth optocoupler and pulling the first output terminal of the fourth optocoupler to a low level to send a low-level enable signal to other battery management units.
4. The battery management unit according to claim 1, characterized in that, When the battery management unit is a non-primary slave controller, the first output terminal of the second optocoupler is used to connect to other battery management units; The controller is configured to detect that the first input terminal of the first optocoupler is at a low level, obtain an incrementing CAN address according to the CAN address of the previous slave controller, and control the second input terminal of the fourth optocoupler to be at a low level, so that the fourth optocoupler is turned on and the first output terminal of the fourth optocoupler is at a low level, thereby triggering the other connected battery management units.
5. The battery management unit according to any one of claims 1-4, characterized in that, The controller is also used to control the second input terminal of the fourth optocoupler to be low after completing the CAN address allocation, so that the fourth optocoupler is turned on; if the first output terminal of the third optocoupler is low, then the controller confirms that the next level slave controller has completed the CAN address allocation.
6. The battery management unit according to claim 5, characterized in that, The controller is also configured to report a fault to the battery control unit via the CAN bus when it detects that the first output terminal of the first optocoupler is at a low level and the CAN address allocation fails, or when the first output terminal of the third optocoupler is not detected to be at a low level.
7. The battery management unit according to claim 6, characterized in that, It also includes resistors; The first input terminal, the second input terminal, and the third input terminal of the first optocoupler are respectively connected to the power supply through a first resistor, a second resistor, and a third resistor; The first input terminal of the second optocoupler is connected to the power supply via a fourth resistor; The first, second, and third input terminals of the third optocoupler are connected to the power supply via the fifth, sixth, and seventh resistors, respectively. The first input terminal of the fourth optocoupler is connected to the power supply via an eighth resistor.
8. The battery management unit according to claim 7, characterized in that, It also includes diodes; The first resistor is connected to the negative terminal of the first diode, and the positive terminal of the first diode is connected to the power supply; the second resistor is connected to the negative terminal of the second diode, and the positive terminal of the second diode is connected to the power supply. The fifth resistor is connected to the negative terminal of the third diode, and the positive terminal of the third diode is connected to the power supply; the sixth resistor is connected to the negative terminal of the fourth diode, and the positive terminal of the fourth diode is connected to the power supply.
9. An energy storage system, characterized in that, Includes a battery control unit and a plurality of battery management units as described in any one of claims 1-8; The battery control unit acts as the master controller, and the multiple battery management units act as slave controllers; among the multiple slave controllers, one is the primary slave controller, and the rest are non-primary slave controllers.
10. The energy storage system according to claim 9, characterized in that, When the master controller receives a fault report from the battery control unit, it sends a low-level enable signal to the first output terminal of the second optocoupler of the master slave controller, so that the first optocoupler is turned on and the first output terminal of the first optocoupler is pulled low.