A communication circuit and battery management system

Abstract

The utility model discloses a communication circuit and battery management system. Communication circuit includes: daisy chain communication bus and isolation module, and isolation module includes capacitor isolation unit and transformer isolation unit, wherein, daisy chain communication bus is used for connecting a plurality of battery management chips, and isolation module is located in daisy chain communication bus, and adjacent battery management chip is connected through capacitor isolation unit, and / or, adjacent battery management chip is connected through transformer isolation unit. The utility model discloses a communication circuit and battery management system, and the selectivity of capacitor isolation and transformer isolation can be realized.

Description

Technical Field

[0001] This utility model relates to battery management technology, and more particularly to a communication circuit and a battery management system. Background Technology

[0002] The battery management system (BMS), as an important component of the battery system, is mainly used to monitor and protect the battery's state. A BMS consists of multiple battery management chips, which are connected via communication circuits.

[0003] Currently, existing communication circuits have the problem of not being able to select the isolation method when realizing communication between different battery management chips. Utility Model Content

[0004] This utility model provides a communication circuit and a battery management system to achieve selectivity between capacitor isolation and transformer isolation.

[0005] In a first aspect, this utility model provides a communication circuit, including: a daisy-chain communication bus and an isolation module, wherein the isolation module includes a capacitor isolation unit and a transformer isolation unit;

[0006] The daisy-chain communication bus is used to connect multiple battery management chips. The isolation module is located on the daisy-chain communication bus. Adjacent battery management chips are connected through the capacitor isolation unit, and / or adjacent battery management chips are connected through the transformer isolation unit.

[0007] Optionally, the capacitor isolation unit includes a first capacitor, a second capacitor, a third capacitor, and a fourth capacitor. The first terminal of the battery management chip is connected to the first terminal of an adjacent battery management chip in sequence through the first capacitor and the second capacitor. The second terminal of the battery management chip is connected to the second terminal of the adjacent battery management chip in sequence through the third capacitor and the fourth capacitor.

[0008] Optionally, the transformer isolation unit includes a transformer, with a first terminal of the battery management chip connected to a first terminal of the primary side of the transformer, a second terminal of the battery management chip connected to a second terminal of the primary side of the transformer, a first terminal of the secondary side of the transformer connected to a first terminal of an adjacent battery management chip, and a second terminal of the secondary side of the transformer connected to a second terminal of the adjacent battery management chip.

[0009] Optionally, the communication circuit further includes a resistor module, which includes a first resistor, a second resistor, and a third resistor. The first terminal of the battery management chip is connected to the isolation module through the first resistor, the second terminal of the battery management chip is connected to the isolation module through the second resistor, and the first terminal of the battery management chip is connected to the second terminal of the battery management chip through the third resistor.

[0010] Optionally, the communication circuit further includes a switching transistor module, which includes a first switching transistor and a second switching transistor. The first terminal of the battery management chip is grounded through the first resistor and the first switching transistor in sequence, and the second terminal of the battery management chip is grounded through the second resistor and the second switching transistor in sequence.

[0011] Optionally, the daisy-chain communication bus is a single bidirectional communication bus.

[0012] Secondly, this utility model provides a battery management system, including the communication circuit as described in the first aspect, and also including a plurality of battery management chips, with adjacent battery management chips connected through the communication circuit.

[0013] Optionally, the battery management system further includes a main control unit connected to each of the battery management chips, the main control unit being used to control the operating state of each of the battery management chips.

[0014] Optionally, the battery management system also includes a bridging chip, through which the main control unit is sequentially connected to each of the battery management chips.

[0015] Optionally, the battery management chip corresponds one-to-one with the battery cell, and the battery management chip is used to manage the corresponding battery cell.

[0016] The communication circuit and battery management system provided in this embodiment of the invention include a daisy-chain communication bus and an isolation module. The isolation module includes a capacitor isolation unit and a transformer isolation unit. The daisy-chain communication bus connects multiple battery management chips, and the isolation module is located on the daisy-chain communication bus. Adjacent battery management chips are connected via capacitor isolation units, and / or, adjacent battery management chips are connected via transformer isolation units. The isolation module includes capacitor isolation units and transformer isolation units, allowing adjacent battery management chips to be selectively connected via either capacitor isolation units or transformer isolation units, thus enabling the selection of either capacitor isolation or transformer isolation. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the structure of a communication circuit provided in an embodiment of the present utility model;

[0018] Figure 2 This is a schematic diagram of the structure of a bridging chip provided in an embodiment of the present invention. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0020] Figure 1 This is a schematic diagram of a communication circuit provided in an embodiment of this utility model. (Reference) Figure 1 The communication circuit includes a daisy-chain communication bus 10 and an isolation module 20. The isolation module 20 includes a capacitor isolation unit 21 and a transformer isolation unit 22. The daisy-chain communication bus 10 is used to connect multiple battery management chips. The isolation module 20 is located on the daisy-chain communication bus 10. Adjacent battery management chips are connected through the capacitor isolation unit 21, and / or adjacent battery management chips are connected through the transformer isolation unit 22.

[0021] In this configuration, there is at least one isolation module 20, but there can be multiple isolation modules 20. For example, there are two isolation modules 20 and three battery management chips. The battery management chips include a first battery management chip, a second battery management chip, and a third battery management chip connected sequentially. The first and second battery management chips are connected through one of the isolation modules 20, and the second and third battery management chips are connected through another isolation module 20. That is, an isolation module 20 is provided between the first and second battery management chips, and between the second and third battery management chips. The isolation module 20 between the first and second battery management chips and the isolation module 20 between the second and third battery management chips are different isolation modules 20. For example, the first and second battery management chips are connected through a capacitor isolation unit 21 of one of the isolation modules 20, and the second and third battery management chips are connected through a transformer isolation unit 22 of the other isolation module 20. Both capacitor isolation unit 21 and transformer isolation unit 22 are optional surface mount components. When the capacitor isolation unit is selected, the adjacent battery management chip connected to the capacitor isolation unit 21 is capacitor isolated. When the transformer isolation unit 22 is selected, the adjacent battery management chip connected to the transformer isolation unit 22 is transformer isolated. This allows the communication circuit to selectively use capacitor isolation and transformer isolation.

[0022] The communication circuit provided in this embodiment includes a daisy-chain communication bus and an isolation module. The isolation module includes a capacitor isolation unit and a transformer isolation unit. The daisy-chain communication bus connects multiple battery management chips. The isolation module is located on the daisy-chain communication bus. Adjacent battery management chips are connected via capacitor isolation units, and / or, adjacent battery management chips are connected via transformer isolation units. In this embodiment, the isolation module includes capacitor isolation units and transformer isolation units, allowing adjacent battery management chips to be selectively connected via either capacitor isolation units or transformer isolation units, thus enabling the choice between capacitor isolation and transformer isolation.

[0023] refer to Figure 1 Optionally, the capacitor isolation unit 21 includes a first capacitor C1, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4. The first terminal A1 of the battery management chip is connected to the first terminal B1 of the adjacent battery management chip in sequence through the first capacitor C1 and the second capacitor C2. The second terminal A2 of the battery management chip is connected to the second terminal B2 of the adjacent battery management chip in sequence through the third capacitor C3 and the fourth capacitor C4.

[0024] In this configuration, the first terminal A1 and the second terminal A2 of the battery management chip are both input terminals, and the first terminal B1 and the second terminal B2 of the adjacent battery management chip are both output terminals; alternatively, the first terminal A1 and the second terminal A2 of the battery management chip are both output terminals, and the first terminal B1 and the second terminal B2 of the adjacent battery management chip are both input terminals. The signals transmitted by the first terminal A1 and the second terminal A2 of the battery management chip are differential signals, and the signals transmitted by the first terminal B1 and the second terminal B2 of the adjacent battery management chip are also differential signals. Taking a battery management chip comprising a first battery management chip and a second battery management chip as an example, when the first terminal A1 and the second terminal A2 of the first battery management chip are both input terminals, the signal is transmitted from the first terminal B1 and the second terminal B2 of the second battery management chip to the first terminal A1 and the second terminal A2 of the first battery management chip through the capacitor isolation unit 21; when the first terminal A1 and the second terminal A2 of the first battery management chip are both output terminals, the signal is transmitted from the first terminal A1 and the second terminal A2 of the first battery management chip to the first terminal B1 and the second terminal B2 of the second battery management chip through the capacitor isolation unit 21. Each battery management chip outputs signals including signals it collects, such as battery temperature and voltage signals. Adjacent battery management chips are connected via capacitor isolation unit 21 to achieve capacitive isolation between adjacent chips.

[0025] Additionally, the third terminal A3 and the fourth terminal A4 of the battery management chip are connected to another adjacent battery management chip, or the third terminal A3 of the battery management chip is connected to one end E1 of the bridge chip, and the fourth terminal A4 of the battery management chip is connected to the other end E2 of the bridge chip. Specifically, the third terminal A3 of the battery management chip is connected to one end E1 of the bridge chip through the fourth resistor R4, and the third terminal A3 of the battery management chip is grounded in sequence through the fourth resistor R4 and the third switch D3. The fourth terminal A4 of the battery management chip is connected to the other end E2 of the bridge chip through the fifth resistor R5, and the fourth terminal A4 of the battery management chip is grounded in sequence through the fifth resistor R5 and the fourth switch D4. The fourth terminal A4 of the battery management chip is connected to the third terminal A3 of the battery management chip through the sixth resistor R6. The function of the resistors and the switch connected to the third terminal A3 and the fourth terminal A4 of the battery management chip can be referred to the function of the resistors and the switch connected to the first terminal A1 and the second terminal A2 of the battery management chip, and will not be repeated here.

[0026] It should be noted that the number of capacitors between the first terminal A1 of the battery management chip and the first terminal B1 of the adjacent battery management chip, the number of capacitors between the second terminal A2 of the battery management chip and the second terminal B2 of the adjacent battery management chip, and the number of capacitors in the capacitor isolation unit 21 are only illustrative and can be determined according to actual communication requirements, and are not limited here.

[0027] refer to Figure 1 Optionally, the transformer isolation unit 22 includes a transformer T, with the first terminal A1 of the battery management chip connected to the first terminal of the primary side of the transformer T, the second terminal A2 of the battery management chip connected to the second terminal of the primary side of the transformer T, the first terminal of the secondary side of the transformer T connected to the first terminal B1 of the adjacent battery management chip, and the second terminal of the secondary side of the transformer T connected to the second terminal B2 of the adjacent battery management chip.

[0028] In this configuration, the first terminal A1 and the second terminal A2 of the battery management chip are both input terminals, and the first terminals B1 and the second terminals B2 of the adjacent battery management chip are both output terminals; alternatively, the first terminals A1 and A2 of the battery management chip are both output terminals, and the first terminals B1 and B2 of the adjacent battery management chip are both input terminals. Taking a battery management chip comprising a first battery management chip and a second battery management chip as an example, when the first terminals A1 and A2 of the first battery management chip are both input terminals, the signal is transmitted from the first terminals B1 and B2 of the second battery management chip to the first terminals A1 and A2 of the first battery management chip via a transformer T; when the first terminals A1 and A2 of the first battery management chip are both output terminals, the signal is transmitted from the first terminals A1 and A2 of the first battery management chip to the first terminals B1 and B2 of the second battery management chip via a transformer T. The signals output by each battery management chip include signals it collects, such as battery temperature and voltage signals. Adjacent battery management chips are connected via transformer T to achieve transformer isolation between adjacent battery management chips.

[0029] refer to Figure 1 Optionally, the communication circuit also includes a resistor module 30, which includes a first resistor R1, a second resistor R2 and a third resistor R3. The first terminal A1 of the battery management chip is connected to the isolation module 20 through the first resistor R1, the second terminal A2 of the battery management chip is connected to the isolation module 20 through the second resistor R2, and the first terminal A1 of the battery management chip is connected to the second terminal A2 of the battery management chip through the third resistor R3.

[0030] Specifically, the first terminal A1 of the battery management chip is connected to the capacitor isolation unit 21 (or transformer isolation unit 22) in the isolation module 20 through the first resistor R1, and the second terminal A2 of the battery management chip is connected to the capacitor isolation unit 21 (or transformer isolation unit 22) in the isolation module 20 through the second resistor R2. That is, the signal is transmitted between the battery management chip and the isolation module 20 through the resistor module 30. The resistor module 30 can compensate for signal attenuation and stabilize the signal level, thereby improving the signal transmission quality.

[0031] refer to Figure 1 Optionally, the communication circuit also includes a switching transistor module 40, which includes a first switching transistor D1 and a second switching transistor D2. The first terminal A1 of the battery management chip is grounded through a first resistor R1 and the first switching transistor D1 in sequence, and the second terminal A2 of the battery management chip is grounded through a second resistor R2 and the second switching transistor D2 in sequence.

[0032] Specifically, when the voltage at the first terminal A1 of the battery management chip is higher than the turn-on voltage of the first switch D1, the first switch D1 is turned on to prevent the overvoltage at the first terminal A1 of the battery management chip from damaging the components in the circuit connected to the first terminal A1 of the battery management chip; when the voltage at the second terminal A2 of the battery management chip is higher than the turn-on voltage of the second switch D2, the second switch D2 is turned on to prevent the overvoltage at the second terminal A2 of the battery management chip from damaging the components in the circuit connected to the second terminal A2 of the battery management chip.

[0033] In addition, the first terminal A1 and the second terminal A2 of the battery management chip are grounded through different capacitors.

[0034] Optionally, the daisy-chain communication bus is a single bidirectional communication bus.

[0035] Specifically, the daisy-chain communication bus is a serial data transmission architecture for multiple nodes, such as multiple battery management chips. The core of the daisy-chain communication bus is the serial connection of multiple nodes. All communication nodes, such as each battery management chip, are connected end-to-end in sequence, forming a linear or ring link with the main control unit in the battery management system. The daisy-chain communication bus supports dozens to hundreds of nodes in series, eliminating the need for complex star wiring and significantly simplifying hardware design. The daisy-chain communication bus is a single-wire bidirectional communication bus, using only 2-4 differential signal lines to achieve communication between all nodes. Compared to CAN bus (requiring a separate controller) or Ethernet (multi-wire), it reduces the number of cables and wiring space, resulting in lower wiring costs. Using differential signal transmission (two lines transmit signals with equal amplitude and opposite phase, canceling out noise), it can resist high-frequency noise and ensure data transmission stability. Note that "single-wire bidirectional" in the context of the daisy-chain communication bus means that a single line in the daisy-chain communication bus can transmit signals bidirectionally, not that the daisy-chain communication bus requires only a single line.

[0036] The communication circuit provided in this embodiment includes a daisy-chain communication bus and an isolation module. The isolation module includes a capacitor isolation unit and a transformer isolation unit. The daisy-chain communication bus connects multiple battery management chips. The isolation module is located on the daisy-chain communication bus. Adjacent battery management chips are connected through capacitor isolation units, and / or, adjacent battery management chips are connected through transformer isolation units. The circuit also includes a resistor module and a switching transistor module. The battery management chips are connected to the isolation module through the resistor module, and the battery management chips are grounded sequentially through the resistor module and the switching transistor module. In this embodiment, the isolation module includes capacitor isolation units and transformer isolation units. Adjacent battery management chips can be connected either through capacitor isolation units or transformer isolation units, thus achieving selectivity between capacitor isolation and transformer isolation.

[0037] This embodiment also provides a battery management system, including the communication circuit as provided in any embodiment of this utility model, and multiple battery management chips, with adjacent battery management chips connected through the communication circuit. Adjacent battery management chips are connected in series through the communication circuit and isolated by an isolation module in the communication circuit to prevent noise interference. The specific structure of the communication circuit can be referred to in any of the above embodiments, and will not be repeated here.

[0038] Optionally, the battery management system also includes a main control unit, which is connected to each battery management chip and is used to control the operating state of each battery management chip.

[0039] Specifically, in a battery management system (BMS), the main control unit (MCU) is the core computing and control unit, typically integrating the controller, memory, timers, and various I / O interfaces onto a single chip. The MCU also monitors battery status: by connecting to voltage measurement ports, current sensors, and temperature sensors, it monitors parameters such as voltage, current, and temperature of the battery pack in real time, providing a data foundation for subsequent analysis and control. Battery protection: When the battery pack experiences abnormal conditions such as overvoltage, undervoltage, overcurrent, or overtemperature, the MCU can promptly trigger protection mechanisms. For example, by sending a shut-off signal to a contactor, it disconnects the battery pack from the load or charging circuit, preventing battery damage due to abnormal operating conditions and avoiding safety accidents. Battery performance optimization: Based on the monitored data, the MCU executes a battery balancing algorithm to manage the balance of individual cells in the battery pack, ensuring that the charge and voltage of each cell are as consistent as possible, reducing internal differences within the battery pack, and extending the overall lifespan of the battery pack. Simultaneously, the MCU can select appropriate charging modes, such as constant current charging or constant voltage charging, based on the battery status to optimize the charging process. Data logging and communication: The main control unit stores relevant data of the battery pack, such as historical voltage, current, temperature, and charge / discharge cycles, for later querying and analysis. In addition, the main control unit communicates with external devices, sending battery status information to charging piles or other host computers, and can also receive instructions from external devices to achieve remote monitoring and management of the battery management system.

[0040] In addition, the main control unit and the battery management chip are connected via a daisy-chain communication bus. The daisy-chain communication bus is the bus in the battery management system that enables efficient communication between the main control unit and multiple battery management chips. The main control unit, acting as the start or end point of data transmission and reception, sends commands to the first node (e.g., the first battery management chip) via the daisy-chain communication bus. The first node processes the command and forwards the data to the second node (e.g., the second battery management chip), and so on, until the last node (e.g., the last battery management chip). Reverse data is transmitted back to the main control unit via the opposite path. Daisy-chain communication in the battery management system is typically based on differential signal transmission to resist electromagnetic interference and common-mode noise within the battery pack. The data transmission process is as follows: Command issuance: The main control unit generates differential command signals through a bridging chip and sends them to the first battery management chip; Node processing and forwarding: After receiving the signal, each node parses the commands related to itself, such as voltage and temperature acquisition commands, executes the operation, and generates response data; simultaneously, it forwards any unprocessed commands to the next node; Data feedback: After the last node completes its processing, it transmits its response data in reverse. Each node appends its own data sequentially, and finally, the data is aggregated into a complete data packet and transmitted back to the main control unit. Battery management systems (BMS) typically monitor a large number of individual batteries; for example, an electric vehicle battery pack may contain hundreds of individual cells. Daisy-chain communication supports dozens to hundreds of nodes connected in series. A BMS can be used for electric vehicles: a daisy-chain communication bus connects the main control unit in the BMS to each battery management chip. Each battery management chip monitors different batteries, transmitting data such as battery voltage, temperature, and equalization status to the main control unit via the daisy-chain communication bus, enabling battery status estimation and protection control. A BMS can also be used for energy storage batteries: large energy storage battery packs (such as containerized energy storage) contain hundreds of battery modules. A daisy-chain communication bus connects the monitoring units of each battery module, enabling centralized monitoring of the entire system's data and supporting remote operation and maintenance. Furthermore, a BMS can be used for power battery packs: within high-voltage battery packs, multiple temperature sensors and voltage acquisition modules are connected via a daisy-chain communication bus, avoiding cable redundancy and signal interference caused by star-shaped wiring. Daisy-chain communication bus has simple wiring, multi-node adaptability, and strong anti-interference. Its design needs to combine differential signal transmission, redundant architecture and protocol optimization to balance real-time performance, reliability and cost. It is the core communication support to ensure that the battery management system can fully monitor and finely control the battery status.

[0041] Figure 2 This is a schematic diagram of the structure of a bridging chip provided in an embodiment of this utility model. (Reference) Figure 2 Optionally, the battery management system also includes a bridging chip U, through which the main control unit 100 is connected to each battery management chip in sequence.

[0042] Among them, ports C1 and C2 of the bridging chip U are connected to the battery management chip. Figure 2 The diagram illustrates the bridging chip U and its peripheral circuitry. Specifically, in the battery management system, the bridging chip U is primarily used to convert the communication protocol and transmit data between the main control unit 100 and the battery management chip, ensuring safe, reliable, and stable communication between them. Since the main control unit 100 and the battery management chip use different communication protocols, the bridging chip U can convert the battery management chip's communication protocol into one that the main control unit 100 can recognize, facilitating data transmission and processing. The bridging chip supports daisy-chain communication mode and both transformer isolation and capacitor isolation methods, and can support a single daisy-chain loopback architecture, making communication between the main control unit 100 and the battery management chip more convenient and efficient. The bridging chip U can process signals, converting the signals transmitted by the main control unit 100 into differential signals, which are then sequentially connected to each battery management chip, improving the anti-interference capability of data transmission. Simultaneously, some bridging chips U have data buffering functions, optimizing the data transmission process and ensuring the stability and efficiency of data transmission. Furthermore, the bridging chip U can be applied to the battery management system of electric vehicles, connecting multiple battery modules of the battery pack to the main control unit of the battery management system. This enables efficient transmission of information such as battery voltage, current, and temperature, helping the main control unit to monitor battery status in real time, perform battery balancing, fault diagnosis, and other operations, ensuring the safety and performance of the electric vehicle battery system. The bridging chip U can also be applied to energy storage systems: in large-scale energy storage power stations, the bridging chip U can accurately transmit data from numerous battery modules to the main control module of the energy storage battery management system, facilitating the monitoring and management of the battery status of the entire energy storage system, and improving the stability and lifespan of the energy storage system.

[0043] For example, the bridging chip is the BQ79600 chip. The BQ79600 chip is a communication interface chip designed for automotive applications, meeting the safety level requirements of automotive safety integrity. In the battery management system, it serves as a communication bridge chip between the main control unit and the battery management chip, suitable for hybrid and electric vehicles, fuel cells, and energy storage systems. The BQ79600 chip is a wide-voltage powered chip: supporting power supplies from 4.75 volts to 40 volts, it can operate stably over a wide voltage range. The BQ79600 chip has multiple communication interfaces, compatible with 3.3 volts / 5 volt logic levels, and can communicate with various microcontrollers. The BQ79600 chip supports a ring architecture, using transformer isolation or capacitor isolation to achieve isolated differential daisy-chain communication. When a fault is detected in the ring architecture, the BQ79600 chip can automatically wake up the battery management system for timely fault handling. The BQ79600 chip has a device temperature rating suitable for an ambient operating temperature range of -40°C to +125°C. It is also designed for battery charging suppression, electromagnetic interference, and electromagnetic compatibility, meeting the safety level requirements of automotive safety integrity levels and offering high reliability.

[0044] Optionally, a battery management chip corresponds one-to-one with a battery cell, and the battery management chip is used to manage the corresponding battery cell.

[0045] The battery unit can include multiple individual cells. The battery management chip can monitor the voltage, current, temperature, and other parameters of the corresponding battery unit in real time and transmit the monitored information to the main control unit via a daisy-chain communication bus. Furthermore, the battery management chip can also perform functions such as charging and discharging management, balancing control, and safety protection for the battery unit to ensure its safe and efficient operation and extend its lifespan. Specifically, the battery management chip can control the charging and discharging process of the battery unit, ensuring that the battery unit operates within a safe voltage and current range, supporting instantaneous high current output, and integrating overcharge and over-discharge protection functions. The battery management chip can also balance the charge of each individual cell in the battery unit to prevent overcharging or over-discharging of individual cells, thus extending the overall lifespan of the battery unit. The battery management chip also has functions such as overvoltage protection, undervoltage protection, overcurrent protection, short circuit protection, and overheat protection to prevent battery damage or safety accidents caused by abnormal conditions. It can monitor the current, voltage, and other states of the battery unit in real time and supports multiple safety modes such as overvoltage, undervoltage, overcurrent discharge, and overcurrent charging. In battery management systems for electric vehicles and energy storage applications, battery management chips play a crucial role in ensuring safe and efficient battery operation, protecting battery performance and lifespan, and improving system reliability and stability.

[0046] The battery management system provided in this embodiment belongs to the same inventive concept as the communication circuit provided in any embodiment of this utility model, and has corresponding beneficial effects. For technical details not covered in this embodiment, please refer to the communication circuit provided in any embodiment of this utility model.

[0047] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A communication circuit, characterized in that, include: A daisy-chain communication bus and an isolation module, wherein the isolation module includes a capacitor isolation unit and a transformer isolation unit; The daisy-chain communication bus is used to connect multiple battery management chips. The isolation module is located on the daisy-chain communication bus. Adjacent battery management chips are connected through the capacitor isolation unit, and / or adjacent battery management chips are connected through the transformer isolation unit.

2. The communication circuit according to claim 1, characterized in that, The capacitor isolation unit includes a first capacitor, a second capacitor, a third capacitor, and a fourth capacitor. The first terminal of the battery management chip is connected to the first terminal of an adjacent battery management chip in sequence through the first capacitor and the second capacitor. The second terminal of the battery management chip is connected to the second terminal of the adjacent battery management chip in sequence through the third capacitor and the fourth capacitor.

3. The communication circuit according to claim 1, characterized in that, The transformer isolation unit includes a transformer. The first end of the battery management chip is connected to the first end of the primary side of the transformer, the second end of the battery management chip is connected to the second end of the primary side of the transformer, the first end of the secondary side of the transformer is connected to the first end of an adjacent battery management chip, and the second end of the secondary side of the transformer is connected to the second end of the adjacent battery management chip.

4. The communication circuit according to any one of claims 1-3, characterized in that, It also includes a resistor module, which includes a first resistor, a second resistor, and a third resistor. The first terminal of the battery management chip is connected to the isolation module through the first resistor, the second terminal of the battery management chip is connected to the isolation module through the second resistor, and the first terminal of the battery management chip is connected to the second terminal of the battery management chip through the third resistor.

5. The communication circuit according to claim 4, characterized in that, It also includes a switching module, which includes a first switching transistor and a second switching transistor. The first terminal of the battery management chip is grounded through the first resistor and the first switching transistor in sequence, and the second terminal of the battery management chip is grounded through the second resistor and the second switching transistor in sequence.

6. The communication circuit according to any one of claims 1-3, characterized in that, The daisy chain communication bus is a single bidirectional communication bus.

7. A battery management system, characterized in that, The device includes the communication circuit described in any one of claims 1-6, and further includes a plurality of battery management chips, with adjacent battery management chips connected through the communication circuit.

8. The battery management system according to claim 7, characterized in that, It also includes a main control unit, which is connected to each of the battery management chips and is used to control the working state of each of the battery management chips.

9. The battery management system according to claim 8, characterized in that, It also includes a bridging chip, through which the main control unit is sequentially connected to each of the battery management chips.

10. The battery management system according to claim 8 or 9, characterized in that, The battery management chip corresponds one-to-one with the battery cell, and the battery management chip is used to manage the corresponding battery cell.

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