Wireless BMS multi-cell multi-physics field high-speed synchronous sampling method and system

Abstract

The invention belongs to the field of battery pack performance and safety monitoring, and discloses a wireless BMS multi-cell multi-physics field high-speed synchronous sampling method and system, and the method comprises the steps: correspondingly connecting a plurality of BMS slave boards with a high-speed data collection function to each single cell in a battery pack, forming a multi-cell monitoring unit, and obtaining multi-physics field information; the data are transmitted to the BMS mainboard through RF wireless communication, so that synchronous state monitoring and safety management of the multiple battery cells are realized; each BMS slave plate can directly collect current, voltage and temperature data, and integrates a gas sensor and a pressure sensor to obtain gas production and surface pressure signals of the battery cell, and converts the signals into voltage signals of AD input; the monitoring system is based on RF wireless communication and synchronously triggers each BMS slave plate to apply a current excitation signal to a single battery cell and collect a voltage response signal, and meanwhile, the response signal is subjected to fast Fourier decomposition through a calculation function so as to complete online synchronous impedance monitoring of multiple battery cells. And each BMS slave board is provided with a FLASH memory.

Description

Technical Field

[0001] The present invention belongs to the field of battery pack performance and safety monitoring, and particularly relates to a wireless BMS multi-cell multi-physical-field high-speed synchronous sampling method and system. Background Art

[0002] Lithium batteries are currently widely used in the field of electrochemical energy storage. Considering safety and manufacturing processes, the capacity and energy density of a single lithium battery have an upper limit. Therefore, single lithium batteries are usually connected in series or parallel to form a battery pack.

[0003] The lithium battery itself is a complex strongly non-linear electrochemical system, and is also affected by the interaction between multiple physical fields. After multi-cell integration, the performance state has a strong correlation with the changes between multiple physical fields. Existing multi-cell safety management products cannot perform multi-physical-field information fusion, and are even less able to obtain impedance information that maps the internal chemical and physical changes of the cells online. There are inaccuracies and delays in multi-cell monitoring; at the same time, existing products mostly use cables to connect each monitoring unit in a daisy chain manner to transmit the collected data, and the external filters affect the signal path, resulting in different trigger and information acquisition time delays, making it difficult to achieve synchronous monitoring of multi-cells, and unable to meet the effectiveness of multi-cell consistency state monitoring and fault warning. In addition, the complex layout of the existing product's wire harness also affects the assembly efficiency and the energy consumption of multi-cells. If the wire harness fails, it will also cause the sampling data to be lost, restricting the application scenarios and safety stability of multi-cells. Therefore, there is an urgent need in the industry for a sampling scheme that comprehensively and synchronously monitors multi-cell multi-physical-field information, obtains impedance information that maps the internal state online, and simultaneously transmits it to the management system at low power consumption, high speed, and synchronously to achieve online safety and consistency state monitoring. Summary of the Invention

[0004] The present invention proposes a wireless BMS multi-cell multi-physical-field high-speed synchronous sampling method and system to solve the defects in the existing sampling methods for online safety and consistency state monitoring of multi-cells, such as high energy consumption, slow efficiency, low recognition accuracy caused by different acquisition time delays, and less application in multi-cells.

[0005] To achieve the above object, the present invention provides the following technical solution: A wireless BMS multi-cell multi-physical-field high-speed synchronous sampling system, comprising:

[0006] At least 1 BMS main board and n BMS slave boards, and the system can achieve high-precision measurement of multi-physical-field parameters such as the voltage, current, pressure, temperature, gas production, and impedance of each single cell in a multi-cell integrated system, and achieve comprehensive monitoring of multi-cells by the battery management system.

[0007] Further, the number n of the BMS slave boards ≥ the number of single cells to be collected in the system, that is, each single cell is equipped with at least one BMS slave board, and redundant design is carried out according to the functional safety requirements.

[0008] Further, the BMS main board and the n BMS slave boards all have (RF) radio frequency wireless communication functions. Each BMS slave board includes, but is not limited to: an AD (analog-to-digital converter), a CPU (data operation unit), a memory (RAM or FLASH), and an RF (radio frequency wireless communication) unit. The above units are integrated by one chip, or can also be integrated by discrete chips through a circuit board, such as an SOC chip of model XL2409.

[0009] Further, the steps of each BMS slave board collecting signals of voltage, current, temperature, gas production, and pressure through sensors and then converting the above signals into voltage signals input to the AD include:

[0010] S31, the cell voltage is directly input to the AD;

[0011] S32, the cell current becomes a voltage signal through a shunt, and then is input to the AD;

[0012] S33, the cell temperature becomes a voltage signal through a thermistor, and then is input to the AD;

[0013] S34, the cell pressure becomes a voltage signal through a flexible pressure-sensitive film arranged on the contact outer surface of each adjacent single cell, and then is input to the AD;

[0014] S35, the gas signal in the environment where the cell is located becomes a voltage signal through a gas-sensitive MEMS, and then is input to the AD.

[0015] Further, each BMS slave board monitors multiple physical quantities including, but not limited to, the voltage, current, temperature, gas production, and pressure of single cells through an AD interface.

[0016] Further, each BMS slave board transmits voltage, temperature, pressure, gas, and impedance data to the main BMS, and the main BMS processes the original data.

[0017] A wireless BMS multi-cell multi-physical field high-speed synchronous sampling method, the specific steps include:

[0018] S4, the AD of each BMS slave board works in a high-speed sampling mode according to the physical quantity characteristics and data processing algorithm requirements, and stores the collected high-frequency data segments in the memory;

[0019] S5, each BMS slave board embeds high-speed data with a sampling period of F2 during the sampling process with a sampling frequency of F1 according to the physical quantity characteristics and data processing algorithm requirements, and F2 is much larger than F1;

[0020] S6, the BMS main board provides a time synchronization function to ensure that all BMS slave boards have the same sampling start time to achieve synchronous sampling. The BMS slave boards use a time-sharing transmission method and transmit multiple sampling cycle data from their respective memories at one time according to the instructions of the BMS main board.

[0021] Furthermore, the step of the BMS main board performing high-speed synchronous sampling through each BMS slave board includes:

[0022] S61, the BMS main board sends a time synchronization command, and all BMS slave boards reset their internal timers;

[0023] S62, the BMS mainboard issues a sampling setting instruction, and all BMSs perform sampling settings, including the type and sequence of physical quantities to be collected, and the sampling time of each physical quantity;

[0024] S63, the BMS mainboard issues a sampling start command; all BMSs perform synchronous sampling according to the settings of S62;

[0025] S64, the BMS issues a command to upload data, and all BMSs upload data packets in sequence. The method of uploading synchronous data packets reduces the power consumption of wireless transmission compared to the method of real-time data transmission.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The high-frequency sampling of a wireless BMS multi-cell multi-physical field high-speed synchronous sampling method system provided by the present invention has the characteristics of synchronization and short time, so that at least one complete transient waveform can be synchronously collected, and then refined diagnosis is performed, including generating high-frequency impedance spectrum data, and only short-time sampling is performed at the same time to ensure that the amount of data is not large;

[0028] 2. The present invention realizes synchronous monitoring of multiple physical fields of multiple cells, so as to timely diagnose inconsistencies and provide safety warnings for multiple cells, and remind technicians to repair or replace faulty single cells in the multiple cells, thereby avoiding accidents that may cause thermal runaway;

[0029] 3. The present invention uses low-power RF wireless communication for signal triggering and information collection, and synchronously collects the real-time multi-physical field states of multiple battery cells based on the BMS main board for inconsistency warning, providing more accurate and reliable data for the performance and safety monitoring of the battery pack. In addition, wireless transmission eliminates complex wiring, which helps reduce the delay in multi-cell data processing and inconsistency fault diagnosis, and at the same time reduces the overall cost of the system and the energy consumption of multi-cells, and is applicable to the field of synchronous state and safety monitoring of battery packs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural diagram of a wireless BMS multi-cell multi-physical field high-speed synchronous sampling system of the present invention;

[0031] Figure 2 It is a block diagram of the composition of a wireless BMS multi-cell multi-physical field high-speed synchronous sampling system of the present invention;

[0032] Figure 3 It is a flowchart of a wireless BMS multi-cell multi-physical field high-speed synchronous sampling system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] A wireless BMS multi-cell multi-physical field high-speed synchronous sampling method and system.

[0035] As Figure 1 shown, the structure of the comprehensive synchronous monitoring system for the multi-physical field of battery cells includes:

[0036] A single-cell monitoring chip, a pressure sensor, a gas sensor, and an RF chip. Among them, the single-cell monitoring chip is used to obtain the voltage, current, temperature, and impedance information of the single battery cell, the pressure sensor and the gas sensor are used to obtain the gas generation information and surface pressure information of the single battery cell, and the RF chip is used to trigger the acquisition signal and data transmission for each BMS board, and is also used to communicate between each single-cell monitoring chip and the BMS main board to realize the synchronous sampling of each single battery cell by the BMS main board coordinating each BMS slave board. It should be noted that some of the above chips or functions are further integrated into a unified chip or decomposed onto a flexible PCB board.

[0037] In this embodiment, the single-cell monitoring chip, gas sensor, pressure sensor, and RF chip are integrated through a flexible circuit board. The flexible circuit board is welded corresponding to the tabs of the single cell, reducing the occupied space of the device to expand the application scenarios of multiple cells.

[0038] In this embodiment, the gas sensor acquires the gas production signal of the single cell and transmits it to the management unit through the conditioning circuit and AD. The pressure sensor is arranged on the contact surface between two adjacent single cells in the battery pack to acquire the pressure signal on the cell surface and transmit it to the management unit through the conditioning circuit and AD.

[0039] It should be noted that the pressure sensor uses a flexible thin-film pressure sensor or a strain gauge, the gas sensor uses a MEMS conductivity-type gas sensor, and the RF single-cell node chip and the BMS main board use the same type of chip.

[0040] In this embodiment, the flexible thin-film sensor technology and the flexible circuit board are adopted to make it easy to integrate between the monitoring device and the single-cell monitoring chip.

[0041] Furthermore, the single-cell monitoring chip has a high-speed ADC function for synchronous triggering and receiving of multi-cell information acquisition with the BMS main board. This monitoring chip can select a general MCU chip or a dedicated cell monitoring chip of NXP DNB1101.

[0042] Specifically, the system obtains the voltage, current, temperature, and impedance information of the single cell corresponding to the connected BMS slave board; obtains the gas production information in the environment where the single cell corresponding to the connected pressure sensor and gas sensor is located and the surface pressure information between adjacent single cells; receives the configuration and signal acquisition instructions sent by the main control chip to the monitoring device through the single-cell node and transmits the acquired data to the coordinator at high speed; the single-cell nodes and the main control chip communicate using RF to realize the wireless synchronous acquisition signal transmission of the main control chip coordinating each single-cell node for the voltage, current, temperature, gas production, and impedance of each single cell.

[0043] As Figure 2 shown, the wireless BMS multi-cell multi-physical field high-speed synchronous sampling system includes:

[0044] At least 1 BMS main board and n BMS slave boards. This system can achieve high-precision measurement of the multi-physical field parameters of each single cell in the multi-cell integrated system and realize the comprehensive monitoring of multiple cells by the battery management system.

[0045] In this embodiment, the number of slave boards of the BMS, n ≥ the number of single cells to be collected in the system, that is, each single cell is equipped with at least one BMS slave board, and redundant design is carried out according to functional safety requirements. Both the BMS main board and the n BMS slave boards have (RF) radio frequency wireless communication functions. Each BMS slave board includes, but is not limited to: an AD (analog-to-digital converter), a CPU (data operation unit), a memory (RAM or FLASH), and an RF (radio frequency wireless communication) unit. The above units are integrated by one chip, or can also be integrated by discrete chips through a circuit board, including an SOC chip of model XL2409.

[0046] Specifically, the BMS main board triggers each BMS slave board to synchronously collect multi-physical field information of each single cell through RF communication, and transmits the collected data to the BMS main board through the RF protocol for analysis and processing to judge the state of multiple cells. If the collected data exceeds the set threshold, a warning message is quickly sent to the cloud server or the host computer for relevant personnel to take corresponding actions. At the same time, each BMS slave board is configured with a large-capacity FLASH to locally store the multi-cell monitoring data, and packs and regularly transmits the daily data to the cloud server for monitoring when there is no fault, reducing the data transmission frequency to reduce the system power consumption. At the same time, the data packet form reduces the RF on time to reduce the wireless power consumption, realizing low-power data transmission and comprehensive monitoring of multi-physical field information of multiple cells.

[0047] As Figure 3 shown, the wireless BMS multi-cell multi-physical field high-speed synchronous sampling method includes:

[0048] The host computer sets the information collection instruction at a fixed time or at any moment for the BMS main board. The BMS main board configures the corresponding sampling parameters according to the instruction parsing result, and synchronously triggers multiple BMS slave boards through the RF chip to collect the voltage, current, temperature, gas production, pressure and impedance information of the single cells connected thereto. The collected data is transmitted to the BMS main board through each single-cell node to complete the high-speed sampling of multi-physical field information of multiple cells.

[0049] It should be noted that each BMS slave board communicates wirelessly with the BMS main board through RF.

[0050] In this embodiment, the steps for each BMS slave board to collect signals of voltage, current, temperature, gas production and pressure through sensors and then convert the above signals into voltage signals input to the AD include:

[0051] S31, the cell voltage is directly input to the AD;

[0052] S32, the cell current becomes a voltage signal through a shunt and then is input to the AD;

[0053] In S33, the temperature of the battery cell is converted into a voltage signal by a thermistor and then input into the AD.

[0054] In S34, the pressure of the battery cell is converted into a voltage signal by a flexible pressure-sensitive film arranged on the contact outer surfaces of adjacent single battery cells and then input into the AD.

[0055] In S35, the gas signal in the environment where the battery cell is located is converted into a voltage signal by a gas-sensing MEMS and then input into the AD.

[0056] It should be noted that the BMS main board wirelessly synchronously triggers each BMS slave board to adopt the same current excitation, and realizes the online synchronous monitoring of the impedance information of multiple battery cells through fast Fourier transform calculation.

[0057] In summary, this solution realizes the high-speed acquisition of multi-physical field information through the BMS slave board configured with an AD (analog-to-digital converter), a CPU (data operation unit), a memory (RAM or FLASH), and an RF (radio frequency wireless communication) unit. Based on RF wireless transmission, it solves the time delay problem caused by complex wiring, completes the high-speed packaging and uploading of monitoring data, realizes the synchronous monitoring of multiple battery cells by the battery management system, so as to timely diagnose the inconsistency and give safety warnings for multiple battery cells, remind technicians to repair or replace the faulty single battery cells in multiple battery cells, and avoid accidents that may cause thermal runaway.

[0058] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0059] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wireless BMS multi-cell multi-physical field high-speed synchronous sampling method and system, characterized by: The method comprises the following steps: S1: The system includes at least one BMS main board and n BMS slave boards, and both the BMS main board and the n BMS slave boards have RF radio frequency wireless communication function; S2: Each BMS slave board includes but is not limited to AD, i.e., analog-to-digital converter, CPU, i.e., data operation unit, memory, including RAM or FLASH, and RF, i.e., radio frequency wireless communication unit. The above units are integrated by a chip or by discrete chips through circuit board integration; S3: Each BMS slave board monitors multiple physical quantities including but not limited to the voltage, current, temperature, gas production and pressure of the single cell through the AD interface; S4: The AD of each BMS slave board works in high-speed sampling mode according to the physical quantity characteristics and data processing algorithm requirements, and stores the collected high-frequency data fragments in the memory; S5: Each BMS slave board embeds high-speed data with a sampling period of F2 during the sampling process with a sampling frequency of F1 according to the physical quantity characteristics and data processing algorithm requirements, and F2 is greater than F1; S6: The BMS main board provides a time synchronization function to ensure that all BMS slave boards have the same sampling start time to achieve synchronous sampling. The BMS slave boards use a time-sharing transmission method to transmit data of multiple sampling cycles from their respective memories at one time according to the instructions of the BMS main board.

2. A wireless BMS multi-cell multi-physical field high-speed synchronous sampling method and system according to claim 1, characterized in that: Step S1 has the following steps: the number of slave boards n≥the number of cells to be collected, that is, each cell is equipped with at least one slave board, and redundancy is performed according to functional safety design.

3. A wireless BMS multi-cell multi-physical field high-speed synchronous sampling method and system according to claim 1, characterized in that: Step S2 has the following steps: AD, namely analog-to-digital converter, CPU, namely data operation unit, memory, including RAM or FLASH and RF, namely radio frequency wireless communication unit is integrated and implemented by SOC chip, including SOC chip of model XL2409.

4. A wireless BMS multi-cell multi-physical field high-speed synchronous sampling method and system according to claim 1, characterized in that: Step S3 comprises the following steps: converting the voltage, current, temperature, gas production and pressure signals into voltage signals for AD input through sensors, including: S31: The cell voltage is directly input to AD; S32: The cell current is converted into a voltage signal through the shunt and then input into AD; S33: The cell temperature is converted into a voltage signal through the thermistor and then input into AD; S34: The cell pressure is converted into a voltage signal through a pressure sensor and then input into AD; S35: The gas generated by the battery cell is converted into a voltage signal through the gas-sensitive MEMS and then input into the AD.

5. A wireless BMS multi-cell multi-physical field high-speed synchronous sampling method and system according to claim 1, characterized in that: Step S6 has the following steps: S61: The BMS main board issues a time synchronization command, and all BMS slave boards reset their internal timers; S62: The BMS mainboard issues a sampling setting instruction, and all BMSs perform sampling settings, including the type and sequence of physical quantities to be collected, and the sampling time of each physical quantity; S63: The BMS mainboard issues a sampling start command; all BMSs perform synchronous sampling according to the settings of S62; S64: The BMS issues a command to upload data, and all BMSs upload data packets in turn.

6. A wireless BMS multi-cell multi-physical field high-speed synchronous sampling method and system according to claim 1, characterized in that: Steps S4-S6 have the following characteristics: High-frequency sampling is synchronous and short-time, which enables synchronous acquisition of at least one complete transient waveform, followed by refined diagnosis, including the generation of high-frequency impedance spectrum data, while only performing high-frequency sampling for a short time to ensure that the amount of data is not large.

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