Battery cell monitoring system based on daisy chain communication

Abstract

The invention provides a daisy chain communication-based battery cell monitoring system, and relates to the technical field of energy storage monitoring, and the system comprises a battery cell monitoring unit which comprises a plurality of sensors and is used for monitoring the basic parameters of a battery cell in real time, and the basic parameters at least comprise the voltage, the current and the temperature; the communication unit is used for controlling the cell monitoring modules to be in bidirectional serial connection to form a daisy chain, and data packets among the cell monitoring modules are in bidirectional flow transmission in the daisy chain by adopting an interface configured with a daisy chain communication protocol; and the power management unit provides a stable power supply for the cell monitoring unit. The problems of complex wiring, high cost and poor expansibility of a battery cell monitoring system in the related technology are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage monitoring, and in particular to a battery cell monitoring system based on daisy chain communication. Background Art

[0002] With the widespread application of electric vehicles and large-scale energy storage systems, the requirements for battery management systems (BMS) are becoming increasingly higher, especially in terms of battery cell monitoring accuracy and communication efficiency. Traditional battery cell monitoring solutions usually adopt parallel or star communication architectures. Although these solutions can achieve fast data transmission, they face problems such as complex wiring, high cost and poor scalability in large-scale battery pack applications. Summary of the invention

[0003] The main purpose of the present invention is to provide a battery cell monitoring system based on daisy chain communication to solve the problems of complex wiring, high cost and poor scalability of the battery cell monitoring system in the related art.

[0004] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a battery cell monitoring system based on daisy chain communication is provided, comprising: a battery cell monitoring unit, comprising a plurality of sensors, for real-time monitoring of basic parameters of the battery cell, wherein the basic parameters include at least: voltage, current and temperature; a communication unit, controlling each battery cell monitoring module to be bidirectionally serially connected to form a daisy chain, using an interface configured with a daisy chain communication protocol, and data packets between each battery cell monitoring module are bidirectionally flowed and transmitted in the daisy chain; a power management unit, providing a stable power supply for the battery cell monitoring unit.

[0005] Furthermore, the battery cell monitoring unit includes: a voltage sensor: using an analog-to-digital converter to measure the voltage of the battery cell; a current sensor: using a Hall effect sensor to non-invasively measure the current passing through the battery cell; a temperature sensor: using an NTC thermistor or a digital temperature sensor to measure the temperature.

[0006] Furthermore, the battery cell monitoring system based on daisy chain communication also includes: a data acquisition unit, which at least includes a data acquisition module, a state evaluation module and a data encapsulation module; wherein the data acquisition module is used to collect data from each sensor at a regular interval and pre-process the collected data; the state evaluation module is used to evaluate the health status of the battery cell according to the state estimation algorithm; the data encapsulation module is used to encapsulate the processed data into a format that complies with the daisy chain communication protocol and send it to the main control unit.

[0007] Furthermore, the communication unit is equipped with two communication interfaces in each battery cell monitoring module, which are respectively used to connect with the previous module and the next module to form a closed-loop daisy chain.

[0008] Furthermore, the type of the communication interface equipped with the battery cell monitoring module is: RS-485 or CAN.

[0009] Furthermore, the communication unit is also equipped with a line monitoring module, which is used to use a collision access strategy to monitor whether the communication line is idle before sending data; if the communication line is idle, start sending data; if the communication line is not idle, wait for a random period of time and try again.

[0010] Furthermore, the battery cell monitoring module assigns different priorities to different types of data packets, and determines the sending order of the data packets according to the priorities.

[0011] Furthermore, the daisy chain communication protocol includes an error detection and retransmission mechanism, and each data packet contains a check bit, which is used by the receiving end to detect whether an error occurs in the data transmission process; if the receiving end finds that there is an error in the data packet, it requests the sending end to retransmit the data packet; the daisy chain communication protocol defines a confirmation mechanism for the retransmission request. After receiving the retransmission request, the sending end resends the data packet and waits for the confirmation of the receiving end. After receiving the confirmation information, it determines that the data packet transmission is successful.

[0012] Furthermore, the power management unit includes: a power isolation module, which is used to use an isolated DC-DC converter to safely isolate the monitoring unit from the high-voltage battery cell; a low-battery detection module, which monitors the power supply voltage in real time, and sends an alarm signal to the main control unit through the communication unit when it is detected that the power supply voltage is lower than a set threshold.

[0013] Furthermore, it also includes: a housing and interface design unit, which encapsulates the battery cell monitoring unit, the data processing unit, the communication unit and the power management unit, and provides an interface with external devices.

[0014] By applying the technical solution of the present invention, the battery cell monitoring system adopts a daisy chain communication method, which has simple wiring, low cost, good scalability, and can effectively improve the battery cell monitoring and management efficiency of large-scale battery packs. In addition, the modular design of the battery cell monitoring system is also convenient for maintenance and upgrading, and is suitable for various complex battery management application scenarios, thereby solving the problems of complex wiring, high cost and poor scalability of the battery cell monitoring system in related technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0016] Figure 1 is a schematic diagram of an optional battery cell monitoring system based on daisy chain communication according to the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0019] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0020] Figure 1 is a schematic diagram of an optional cell monitoring system based on daisy chain communication according to the present invention, such as Figure 1 As shown, the battery cell monitoring system based on daisy chain communication includes: a battery cell monitoring unit 101 , a communication unit 102 , and a power management unit 103 .

[0021] The battery cell monitoring unit 101 includes a plurality of sensors for real-time monitoring of basic parameters of the battery cells, wherein the basic parameters include at least voltage, current and temperature.

[0022] Furthermore, the cell monitoring unit is the core part of the battery management system, which is responsible for collecting basic parameters of the cell, such as voltage, current and temperature. Each cell monitoring unit includes: voltage sensor, current sensor, temperature sensor.

[0023] Voltage sensor: A high-precision analog-to-digital converter (ADC) is used to measure the voltage of the battery cell. In order to improve the accuracy and reliability of the measurement, a differential signal input is used to reduce noise interference.

[0024] Current sensor: Uses a Hall effect sensor to non-intrusively measure the current through the battery cell. This sensor provides high-precision current measurement and has good immunity to environmental interference.

[0025] Temperature sensor: Use NTC thermistor or digital temperature sensor for temperature measurement to ensure that the temperature is accurately monitored during the operation of the battery cell, thereby avoiding safety problems caused by overheating.

[0026] These sensors are all connected to a microprocessor, which is responsible for reading the sensor data and performing preliminary data formatting.

[0027] The communication unit 102 controls each cell monitoring module to be bidirectionally serially connected to form a daisy chain, using an interface configured with a daisy chain communication protocol, and data packets between the cell monitoring modules flow and transmit bidirectionally in the daisy chain.

[0028] In the battery monitoring module of the present invention, the daisy chain communication unit is a key component for realizing efficient and reliable data transmission between modules. The daisy chain communication protocol forms a closed-loop link, allowing data to be transmitted bidirectionally between modules, greatly improving the reliability and efficiency of communication.

[0029] The daisy chain communication protocol is a special serial communication protocol that allows multiple devices to communicate bidirectionally on a closed-loop link. Compared with the traditional star or parallel communication architecture, the daisy chain communication protocol has the advantages of simple wiring, low cost, and good scalability. It is very suitable for application scenarios such as battery cell monitoring equipment modules that require a large number of modules to be interconnected.

[0030] In this embodiment, when designing the daisy chain communication protocol, the following key factors need to be considered:

[0031] 1. Data packet format: Define a unified data packet format, including start bit, address bit, data bit, check bit and stop bit. This ensures the integrity and consistency of the data during transmission. 2. Communication rate: Select a suitable communication rate based on the actual application requirements and communication environment. A higher communication rate can improve data transmission efficiency, but it may also increase the risk of data loss. 3. Conflict detection and resolution mechanism: Design an effective conflict detection and resolution mechanism to avoid conflicts and interference during data transmission. Furthermore, the communication unit is equipped with two communication interfaces on each battery cell monitoring module, which are used to connect to the previous module and the next module respectively to form a closed-loop daisy chain.

[0032] In the daisy chain communication solution, each submodule is connected through a serial communication interface to form a closed loop link. The specific deployment method is as follows:

[0033] Series connection: Each battery cell monitoring module is connected to adjacent modules through two serial communication interfaces. For example, the output interface of module A is connected to the input interface of module B, the output interface of module B is connected to the input interface of module C, and so on. The output interface of the last module is connected back to the input interface of the first module, forming a ring link.

[0034] Bidirectional communication: Each module in the link can send and receive data in both directions. Bidirectional communication is achieved through the daisy chain communication protocol, which allows data packets to be transmitted in a circular path in the link, so that each module can communicate with other modules in the link.

[0035] Closed-loop link: The key to forming a closed loop is to ensure that the two ends of the link are connected. In this way, any module can send data to other modules through the closed-loop link to ensure the reliability and redundancy of communication. The closed-loop design also allows data to continue to be transmitted through the link in the other direction when a module fails, enhancing the fault tolerance of the system.

[0036] Optionally, in a daisy chain communication scheme, the data of each battery cell is sequentially transmitted to the communication planning unit in series, and the daisy chain communication has the advantages of low cost and easy implementation. At the same time, this embodiment provides a CAN communication module as a redundant channel for daisy chain communication, which can continue to maintain data transmission when the daisy chain communication fails to avoid information vacuum. The daisy chain communication unit monitors the integrity, bit error rate, delay and other parameters of the communication signal in real time. Through the analysis of these data, the system can timely understand the current daisy chain communication status and judge the stability and reliability of the communication.

[0037] This embodiment also provides a communication planning unit, which can decide whether to switch to CAN communication according to the situation of daisy chain communication, and comprehensively manage the data transmission between CAN communication unit and daisy chain communication unit. The communication planning unit can dynamically adjust the communication strategy of the system according to the transmission power of the CAN communication unit and the signal integrity of the daisy chain communication unit. For example, when the battery monitoring device is in a charging and discharging state, the communication planning unit will give priority to daisy chain communication with higher communication quality for data transmission. However, if it is detected that the bit error rate in the daisy chain communication increases or the signal attenuation is more serious, the communication planning unit will automatically switch to CAN communication to ensure that the data transmission is not interrupted. The communication planning unit can not only manage communications locally, but also adjust the communication strategy of the system through instructions issued by the cloud platform or server. For example, during the peak period of the energy storage system, the communication planning unit can increase the transmission rate of the data by increasing the transmission power of the daisy chain communication unit to ensure the real-time performance of key data.

[0038] Furthermore, the cell monitoring module is equipped with a communication interface of the type: RS-485 or CAN.

[0039] Each battery cell monitoring equipment module is equipped with two communication interfaces, which are used to connect to the previous module and the next module respectively, forming a closed-loop daisy chain. These communication interfaces usually use standard serial communication interfaces, such as RS-485 or CAN, because these interfaces have good anti-interference ability and long transmission distance.

[0040] In order to achieve two-way communication, the microprocessor inside each module needs to be able to automatically switch between the sending and receiving modes according to the protocol. This is usually achieved through programming, for example, when the microprocessor detects that the communication line is idle, it switches to the sending mode to send data; when receiving data sent by other modules, it switches to the receiving mode.

[0041] Furthermore, the communication unit is also equipped with a line monitoring module, which is used to use a collision access strategy to monitor whether the communication line is idle before sending data; if the communication line is idle, it starts sending data; if the communication line is not idle, it waits for a random period of time and then tries again.

[0042] In daisy chain communication, data collision is an issue that requires special attention. When two or more modules send data almost at the same time, data collision may occur, resulting in data transmission failure. To solve this problem, the following strategy is adopted: Carrier Sense Multiple Access / Collision Detection (CSMA / CD): Before sending data, the module first monitors whether the communication line is idle. If the line is idle, it starts to send data; if the line is busy, it waits for a random time and then tries again. Among them, Carrier Sense Multiple Access (Carrier Sense Multiple Access with Collision Avoidance, referred to as CSMA) is a multiple access protocol for wireless communication. In CSMA, before sending data, the device will first monitor whether there are other devices sending data on the channel. If so, it will wait for a while before trying to send to avoid collision. It can effectively reduce the probability of collision and improve communication efficiency. Collision Detection (CD): If two computers send data at the same time and a collision occurs, the CSMA / CD protocol will immediately stop sending data and send a collision signal. Each computer will wait for a random time before resending data to reduce the possibility of another collision.

[0043] Furthermore, the battery cell monitoring module assigns different priorities to different types of data packets, and determines the sending order of the data packets according to the priorities.

[0044] In order to solve the data conflict problem, this embodiment also adopts priority control: different priorities are assigned to different types of data packets. When a conflict occurs, the data packet with a high priority can be sent first, while the data packet with a low priority is delayed.

[0045] Furthermore, the daisy chain communication protocol includes an error detection and retransmission mechanism. Each data packet contains a check bit, which is used by the receiving end to detect whether an error occurs in the data transmission process. If the receiving end finds that there is an error in the data packet, it requests the sending end to retransmit the data packet. The daisy chain communication protocol defines a confirmation mechanism for the retransmission request. After receiving the retransmission request, the sending end resends the data packet and waits for the confirmation of the receiving end. After receiving the confirmation information, it determines that the data packet transmission is successful.

[0046] In order to ensure the reliability of data transmission, the daisy chain communication protocol also includes an error detection and retransmission mechanism. Each data packet contains a check bit, such as a cyclic redundancy check (CRC) code, which is used by the receiving end to detect whether an error occurred during the data transmission process. If the receiving end finds that there is an error in the data packet, it will request the sending end to retransmit the data packet. In addition, in order to avoid the loss or error of the retransmission request itself, the protocol also defines a confirmation mechanism for the retransmission request. After receiving the retransmission request, the sending end will resend the data packet and wait for the confirmation of the receiving end. Only after receiving the confirmation, the data transmission is considered successful.

[0047] It should also be noted that the microprocessor inside each module automatically switches between the transmit and receive modes through the following mechanisms:

[0048] The first step, initial setup: The microprocessor sets the working mode of the serial communication interface during initialization, enabling it to switch between receiving and transmitting modes. This is usually achieved through a combination of hardware configuration and software control.

[0049] Step 2, monitoring mode: By default, the microprocessor is in monitoring mode (i.e., receiving mode), continuously monitoring the data stream on the serial communication interface. When a valid data packet is detected, the microprocessor enters the data processing flow.

[0050] Step 3, Send Request: When data needs to be sent, the microprocessor first checks whether the communication line is idle (carrier sense). If the line is idle, the microprocessor switches to the send mode and prepares to send the data packet.

[0051] Step 4: Switch between sending and receiving: In the sending mode, after the microprocessor sends a data packet, it immediately switches back to the listening mode and waits for receiving confirmation information or other data packets. The specific implementation methods are as follows: Hardware interrupt: Using the hardware interrupt mechanism, an interrupt is triggered when the transmission is completed or data is received, notifying the microprocessor to switch modes. Software polling: The microprocessor periodically polls the serial communication interface status and switches the sending and receiving modes according to the interface status.

[0052] Step 5, collision detection: Before sending data, the microprocessor detects whether the communication line is idle through the carrier sense multiple access / collision detection (CSMA / CD) mechanism. If a collision is detected, the microprocessor will wait for a random time and then retry to send data.

[0053] Step 6, Data Confirmation and Retransmission: After sending the data packet, the microprocessor waits for confirmation information from the receiving end. If no confirmation is received or error detection information (such as CRC error) is received, the microprocessor will resend the data packet and continue to wait for confirmation until the data transmission is successful.

[0054] The power management unit 103 provides a stable power supply for the battery cell monitoring unit.

[0055] Furthermore, the power management unit includes: a power isolation module, which is used to use an isolated DC-DC converter to safely isolate the monitoring unit from the high-voltage battery cell; a low-battery detection module, which monitors the power supply voltage in real time and sends an alarm signal to the main control unit through the communication unit when it is detected that the power supply voltage is lower than a set threshold.

[0056] Among them, the low power detection module needs to monitor the power supply voltage in real time. Once it detects that the voltage is lower than the set threshold, it sends an alarm signal to the main control unit through daisy chain communication.

[0057] The battery cell monitoring system of this embodiment adopts a daisy chain communication method, which has simple wiring, low cost, good scalability, and can effectively improve the battery cell monitoring and management efficiency of large-scale battery packs. In addition, the modular design of the battery cell monitoring system is also convenient for maintenance and upgrading, and is suitable for various complex battery management application scenarios, thereby solving the problems of complex wiring, high cost and poor scalability of the battery cell monitoring system in related technologies.

[0058] Furthermore, the battery cell monitoring system based on daisy chain communication also includes: a data acquisition unit, which at least includes a data acquisition module, a state evaluation module and a data encapsulation module; wherein the data acquisition module is used to collect data from each sensor at a regular interval and pre-process the collected data; the state evaluation module is used to evaluate the health status of the battery cell according to the state estimation algorithm; the data encapsulation module is used to encapsulate the processed data into a format that complies with the daisy chain communication protocol and send it to the main control unit.

[0059] Furthermore, it also includes: a housing and interface design unit, a packaged battery cell monitoring unit, a data processing unit, a communication unit and a power management unit, and provides an interface with external devices.

[0060] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0061] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0062] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A battery cell monitoring system based on daisy chain communication, characterized in that: include: A battery cell monitoring unit, comprising a plurality of sensors, for real-time monitoring of basic parameters of the battery cell, wherein the basic parameters at least include: voltage, current and temperature; The communication unit controls each battery cell monitoring module to be connected in a bidirectional serial manner to form a daisy chain, and uses an interface configured with a daisy chain communication protocol, so that data packets between the battery cell monitoring modules flow and transmit bidirectionally in the daisy chain; The power management unit provides stable power to the battery monitoring unit.

2. The battery cell monitoring system according to claim 1, characterized in that: The battery cell monitoring unit comprises: Voltage sensor: uses an analog-to-digital converter to measure the voltage of the battery cell; Current sensor: Uses Hall effect sensors to non-intrusively measure the current through the battery cell; Temperature sensor: NTC thermistor or digital temperature sensor is used for temperature measurement.

3. The battery cell monitoring system according to claim 1, characterized in that: Also includes: The data acquisition unit at least includes a data acquisition module, a state evaluation module and a data encapsulation module; The data acquisition module is used to collect data from each sensor at a regular time and pre-process the collected data; The state evaluation module is used to evaluate the health state of the battery cell according to the state estimation algorithm; The data encapsulation module is used to encapsulate the processed data into a format that complies with the daisy chain communication protocol and send it to the main control unit.

4. The battery cell monitoring system according to claim 1, characterized in that: The communication unit is equipped with two communication interfaces in each battery cell monitoring module, which are respectively used to connect with the previous module and the next module to form a closed-loop daisy chain.

5. The battery cell monitoring system according to claim 4, characterized in that: The type of communication interface equipped with the battery cell monitoring module is: RS-485 or CAN.

6. The battery cell monitoring system according to claim 4, characterized in that: The communication unit is also equipped with a line monitoring module for monitoring whether the communication line is idle using a collision access strategy before sending data; If the communication line is in an idle state, data transmission begins; if the communication line is in a non-idle state, retry after waiting for a random period of time.

7. The battery cell monitoring system according to claim 4, characterized in that: The battery cell monitoring module assigns different priorities to different types of data packets, and determines the sending order of the data packets according to the priorities.

8. The battery cell monitoring system according to claim 4, characterized in that: The daisy chain communication protocol includes an error detection and retransmission mechanism, and each data packet includes a check bit for the receiving end to detect whether an error occurs in the data transmission process; If the receiving end finds that there is an error in the data packet, it requests the sending end to retransmit the data packet; The daisy chain communication protocol defines a confirmation mechanism for retransmission requests. After receiving the retransmission request, the sending end resends the data packet and waits for confirmation from the receiving end. After receiving the confirmation information, it is determined that the data packet transmission is successful.

9. The battery cell monitoring system according to claim 1, characterized in that: The power management unit includes: Power isolation module, used to use isolated DC-DC converter to safely isolate the monitoring unit from the high-voltage battery cell; The low power detection module monitors the power supply voltage in real time, and sends an alarm signal to the main control unit through the communication unit when it is detected that the power supply voltage is lower than a set threshold.

10. The battery cell monitoring system according to claim 1, characterized in that: Also includes: The housing and interface design unit encapsulates the battery cell monitoring unit, the data processing unit, the communication unit and the power management unit, and provides an interface with external devices.

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