Single-BMU multi-battery pack parallel system architecture for eVTOL and control method thereof

Abstract

The invention discloses a single-BMU multi-battery-pack parallel system architecture for eVTOL and a control method of the single-BMU multi-battery-pack parallel system architecture, and relates to the technical field of electric vertical take-off and landing aircrafts. The system architecture comprises a battery management unit, a battery junction box and a plurality of battery monomer management units, the battery management unit is respectively in communication connection with the battery junction box and each battery monomer management unit through the communication module; the battery monomer management units are respectively and correspondingly configured in different battery packs and are used for acquiring battery cell data of the corresponding battery packs; the battery junction box is used for monitoring the overall electrical parameters and the high-low voltage isolation state of the battery system. The single-BMU multi-battery pack parallel system architecture for eVTOL and the control method thereof provided by the invention are used for reducing the space occupation of a battery management system, simplifying the system complexity and improving the temperature management efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric vertical take-off and landing aircraft, and particularly relates to a single BMU multi-battery pack parallel system architecture for eVTOL and a control method thereof. BACKGROUND

[0002] As a new type of aircraft, the power core of the electric vertical take-off and landing aircraft (eVTOL) relies on a high-voltage lithium-ion power battery system, and the performance of the system directly determines the flight safety, endurance mileage and operation efficiency of the eVTOL. At present, the research on the power battery system in the eVTOL industry is still in the early stage, and the existing scheme mostly refers to the battery pack architecture design of the traditional new energy vehicle, which has significant adaptation defects: high space and weight occupation: the requirements of the eVTOL on the machine body space and the overall weight are much higher than those of the vehicle, and the weight directly affects the endurance and take-off efficiency. In the existing multi-battery management system (BMS) architecture, each battery pack is configured with an independent battery management unit (BMU), a communication module and a control circuit, the number of hardware is multiplied, which not only occupies a large amount of space, but also significantly increases the overall weight of the machine, and cannot meet the lightweight demand of the eVTOL.

[0003] High system complexity and high cost: under the multi-BMS architecture, the BMS of each battery pack needs to be independently collected, communicated and controlled, which leads to complex electrical lines, increases the number of fault points and improves the difficulty of line arrangement. At the same time, multiple sets of BMS hardware greatly increase the production cost, which is not conducive to the large-scale application of the eVTOL.

[0004] Low temperature management efficiency: the working temperature of the lithium-ion battery directly affects the discharge efficiency and service life, and the battery pack generates heat during the flight of the eVTOL, which needs efficient heat management. However, in the multi-BMS architecture, the temperature control of each battery pack is independent, and unified balancing cannot be achieved, some battery packs are overheated or overcooled, which leads to a decrease in the overall discharge efficiency, and the independent heat management components further increase the space and weight. SUMMARY

[0005] The present application aims to provide a single BMU multi-battery pack parallel system architecture for eVTOL and a control method thereof, which is used for reducing the space occupation of the battery management system, simplifying the system complexity and improving the temperature management efficiency.

[0006] In order to achieve the above object, the present application provides the following technical scheme: a single BMU multi-battery pack parallel system architecture for eVTOL, comprising a battery management unit (BMU), a battery junction box (BJB) and a plurality of battery monomer management units (CMU); the battery management unit comprises a first MCU module, and a battery pressure monitoring sensor module, a high-voltage contactor driver module, a power management module, a CAN communication module and a first daisy chain communication module electrically connected with the first MCU module respectively; the battery junction box comprises a second MCU module, and an isolation measurement module and a second daisy chain communication module electrically connected with the second MCU module respectively; the battery monomer management unit comprises a third MCU module, and a battery voltage acquisition module and a voltage balancing module electrically connected with the third MCU module respectively; the battery management unit is communicatively connected with the battery junction box and each battery monomer management unit through the first daisy chain communication module; each battery monomer management unit is correspondingly arranged in a different battery pack and used for acquiring cell data of the corresponding battery pack; and the battery junction box is used for monitoring overall electrical parameters and high-low voltage isolation states of the battery system.

[0007] Optionally, the power management module and the first MCU module of the battery management unit form a minimum working system to provide stable power supply for all modules of the battery management unit; and the high-voltage contactor driver module reserves an expansion interface for connecting a liquid cooling control component to realize expansion control of a liquid cooling system.

[0008] Optionally, the voltage balancing module of the battery monomer management unit is directly connected with the battery voltage acquisition module; the battery voltage acquisition module transmits cell voltage data to the third MCU module of the battery monomer management unit; and after receiving the balancing instruction of the battery management unit, the battery monomer management unit controls the voltage balancing module to perform charge-discharge adjustment on the cell with voltage deviation out of range, so that the voltages of the cells tend to be consistent.

[0009] Optionally, the isolation measurement module of the battery junction box is used for detecting the insulation resistance value of the low-voltage circuit and the high-voltage circuit; when the insulation resistance value is lower than a preset threshold value, the second MCU module of the battery junction box sends a fault signal to the battery management unit through the second daisy chain communication module, and the battery management unit triggers a fault processing mechanism.

[0010] Optionally, the CAN communication module of the battery management unit is used for establishing bidirectional communication with the eVTOL vehicle controller, uploading battery system state data, and receiving charge-discharge and thermal management instructions issued by the vehicle controller.

[0011] A control method for a single-BMU multi-cell-pack parallel system architecture of an eVTOL, based on the above system architecture, comprising: S1: system power-on initialization: the power management module of the BMU establishes a minimum working system, establishes communication with the BJB and each CMU through the first daisy chain communication module, and checks the initial state, and triggers a warning in an abnormal case.

[0012] S2: charging control: the BMU controls the high-voltage contactor driver module to perform pre-charging operation, switches to fast-charging mode after pre-charging is completed, and simultaneously realizes cell voltage equalization through the CMU.

[0013] S3: Discharge control: BMU controls the discharge loop to be turned on according to the power demand, and monitors the discharge current and cell state in real time, and adjusts the power supply loop in an abnormal case.

[0014] S4: Data monitoring and processing: the BJB and each CMU continuously collect system parameters and cell data, upload them to the BMU for summary analysis and feedback to the vehicle controller.

[0015] S5: Safety and temperature management: BMU warns of the risk of heat escape through battery pressure monitoring, adjusts the heat management components in combination with temperature data, and balances the temperature of each battery pack.

[0016] Optionally, the process of temperature equalization control in step S5 is: the BMU calculates the temperature difference of each battery pack uploaded by the CMU, and when the difference exceeds the preset equalization range, controls the heat exchanger to adjust the flow of heat exchange medium flowing through each battery pack, so that the temperature of each battery pack is maintained in the preset working interval.

[0017] Compared with the prior art, in the system architecture provided by the present application, a single BMU replaces multiple BMSs, reducing the hardware occupation of the BMU, and multiple battery packs are connected in parallel to realize redundancy, so that individual pack failure does not affect the power, while retaining complete cell monitoring functions, improving the available space and endurance of the eVTOL; the architecture supports adjusting the number of battery packs, voltage platforms and communication methods, and can adapt to different models of eVTOLs without significant modification of hardware, has strong scalability, and adapts to multiple scene requirements; a single BMU centrally controls, reduces the number of BMS hardware and wiring, simplifies circuit design, reduces research and development costs, and is conducive to large-scale application; a single BMU uniformly controls the temperature of multiple battery packs, temperature equalization can be realized through a single heat exchanger, without the need for independent heat management components, and the replacement cost is effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The connection diagram of the system architecture provided by the embodiment of the present application is shown.

[0019] Figure 2 The connection relationship diagram of the modules of the BMU provided by the embodiment of the present application is shown.

[0020] Figure 3 A CMU module connection relationship schematic diagram provided for an embodiment of the present application.

[0021] Figure 4 A BJB module connection relationship schematic diagram provided for an embodiment of the present application.

[0022] Figure 5 A flow chart of a control method applied to a system architecture provided for an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects more clearly understood, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0024] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0025] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited. The meaning of "several" is one or more, unless otherwise explicitly specified and limited.

[0026] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0027] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0028] Referring to Figures 1-5 The single BMU multi-battery pack and parallel system architecture for eVTOL provided by the embodiment of the application comprises a battery management unit (BMU), a battery junction box (BJB), and a plurality of battery monomer management units (CMU); the battery management unit comprises a first MCU module, and a battery pressure monitoring sensor module, a high-voltage contactor driver module, a power management module, a CAN communication module, and a first daisy chain communication module electrically connected with the first MCU module respectively; the battery junction box comprises a second MCU module, and a high-voltage measurement module, a current measurement module, a temperature measurement module, an isolation measurement module, and a second daisy chain communication module electrically connected with the second MCU module respectively; the battery monomer management unit comprises a third MCU module, and a battery voltage acquisition module, a voltage balancing module, a temperature acquisition module, and a third daisy chain communication module electrically connected with the third MCU module respectively; the battery management unit is in communication connection with the battery junction box and each battery monomer management unit through the first daisy chain communication module respectively; each battery monomer management unit is correspondingly configured in a different battery pack, and is used for acquiring cell data of the corresponding battery pack; and the battery junction box is used for monitoring overall electrical parameters and high-low voltage isolation states of the battery system.

[0029] Specifically, the battery management unit serves as a system core control unit, all modules in the BMU are electrically connected with the first MCU module, the power management module takes power from the battery system and converts it into stable voltages required by each module, and the first MCU module forms a minimum working system to ensure fast initialization after power-on; the battery pressure monitoring sensor module acquires internal pressure of the battery pack in real time, and transmits data to the first MCU to trigger a warning when the pressure is abnormal (indicating thermal runaway); the high-voltage contactor driver module receives a first MCU instruction, controls on-off of a charging and discharging circuit and a pre-charging circuit contactor, and realizes switching of a charging and discharging mode; an expansion interface is reserved, a liquid cooling control component can be connected, and liquid cooling expansion is supported in the later stage; the CAN communication module communicates with a vehicle controller of the eVTOL in both directions, uploads battery system states (such as power, temperature, and faults), receives charging and discharging and thermal management instructions, the first daisy chain communication module establishes serial communication with the BJB and each CMU, transmits data and instructions, and ensures efficient and stable communication and strong anti-interference capability.

[0030] In the application, the power management module of the battery management unit and the first MCU module form a minimum working system to provide stable power supply for all modules of the battery management unit; the high-voltage contactor driver module reserves an expansion interface for connecting a liquid cooling control component to realize expansion control of a liquid cooling system.

[0031] Referring to Figure 3In an embodiment provided in the application, the voltage balancing module of the battery cell management unit is directly connected with the battery voltage acquisition module; the battery voltage acquisition module transmits the cell voltage data to the third MCU module of the battery cell management unit, and after the battery cell management unit receives the balancing instruction of the battery management unit, the battery cell management unit controls the voltage balancing module to perform charge and discharge adjustment on the cell with voltage deviation out of range, so that the voltages of the cells tend to be consistent.

[0032] A plurality of battery cell management units are correspondingly arranged in different battery packs, and each battery pack has at least one CMU. All modules in the CMU are electrically connected with the third MCU module. The battery voltage acquisition module acquires the cell voltage in real time and uploads it to the BMU. The temperature acquisition module acquires the temperature of the cell or the shell in the battery pack to provide data for temperature balancing. The voltage balancing module receives the balancing instruction of the BMU and adjusts the cell with voltage deviation out of range through passive (resistor discharge) or active (energy transfer) methods to ensure that the voltages of the cells are consistent. The third daisy chain communication module communicates with the BMU to realize cell data uploading and balancing instruction receiving.

[0033] Please refer to Figure 4 In the application, the isolation measurement module of the battery junction box is used to detect the insulation resistance value of the low-voltage circuit and the high-voltage circuit. When the insulation resistance value is lower than a preset threshold, the second MCU module of the battery junction box sends a fault signal to the battery management unit through the second daisy chain communication module, and the battery management unit triggers a fault handling mechanism.

[0034] The battery junction box serves as an electrical parameter monitoring unit. All modules in the BJB are electrically connected with the second MCU module. The high-voltage measurement module acquires the total voltage of the battery system to provide a basis for the BMU to judge the charge and discharge state (such as whether the pre-charging is completed). The current measurement module acquires the total charge and discharge current to avoid overcurrent risk. The temperature measurement module acquires the battery cabin environmental temperature, which is complementary to the cell temperature data of the CMU to support comprehensive temperature management. The isolation measurement module detects the insulation resistance of the high and low voltage circuits and sends a fault signal to the BMU when the insulation is abnormal. The second daisy chain communication module serves as a communication bridge between the BJB and the BMU to realize bidirectional transmission of data and instructions.

[0035] In the application, the CAN communication module of the battery management unit is used to establish bidirectional communication with the eVTOL whole vehicle controller, upload battery system state data, and receive the charge and discharge and thermal management instructions issued by the whole vehicle controller.

[0036] Please refer to Figure 5In a second aspect, the application further provides a control method for a single-BMU multi-battery-pack parallel system architecture of an eVTOL, which is implemented based on the above system architecture and includes the following steps: S1: system power-on initialization: the power management module of the BMU establishes a minimum working system, communicates with the BJB and each CMU through the first daisy chain communication module, and checks the initial state. If an abnormality occurs, a warning is triggered.

[0037] Specifically, after the eVTOL is powered on, the BMU power management module establishes a minimum working system, the first MCU initializes the communication module, and communicates with the BJB and each CMU through the daisy chain to receive initial state data. The BMU checks the data. If there is a fault (such as isolation abnormality, cell overvoltage), the BMU sends a warning to the vehicle controller through the CAN and prohibits charging and discharging. If the state is normal, the BMU enters standby mode and waits for instructions.

[0038] S2: charging control: the BMU controls the high-voltage contactor driver module to perform pre-charging operation, switches to fast-charging mode after pre-charging is completed, and simultaneously realizes cell voltage equalization through the CMU.

[0039] S3: discharging control: the BMU controls the discharging circuit to be turned on according to the power demand, monitors the discharging current and cell state in real time, and adjusts the power supply circuit when an abnormality occurs.

[0040] S4: data monitoring and processing: the BJB and each CMU continuously collect system parameters and cell data, upload them to the BMU for summary analysis and feedback to the vehicle controller.

[0041] Specifically, throughout the system operation, the BJB uploads the total voltage, current, environmental temperature, and isolation resistance every preset time interval; each CMU synchronously uploads the cell voltage and battery pack temperature; the BMU summarizes the data, generates a status report, uploads it to the vehicle controller through the CAN, and stores the data for later maintenance.

[0042] S5: safety and temperature management: the BMU warns of the risk of thermal runaway through battery pressure monitoring, adjusts the thermal management components in combination with temperature data, and balances the temperature of each battery pack.

[0043] Specifically, the process of temperature equalization control in step S5 is as follows: the BMU calculates the temperature difference of each CMU uploaded battery pack, and when the difference exceeds the preset equalization range, controls the heat exchanger to adjust the flow rate of the heat exchange medium flowing through each battery pack, so that the temperature of each battery pack is maintained within the preset working interval.

[0044] It can be known from the above system architecture and control method that the single BMU replaces the multiple BMS, reduces the hardware occupation of the BMU, realizes redundancy through parallel connection of multiple battery packs, does not affect the power in case of individual pack failure, retains complete cell monitoring function, improves the available space and endurance of the eVTOL; the architecture supports adjustment of the number of battery packs, voltage platform and communication mode, can adapt to different models of eVTOL without substantial modification of hardware, has strong scalability and adapts to multiple scene requirements; the single BMU centrally controls and manages, reduces the number of BMS hardware and wiring harness, simplifies circuit design, reduces research and development cost, and is conducive to large-scale application; the single BMU uniformly controls the temperature of multiple battery packs, temperature balance can be realized through a single heat exchanger, independent thermal management components are not needed, and the replacement cost in the later period is effectively reduced.

[0045] In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0046] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A single BMU multi-battery pack parallel system architecture for eVTOL, characterized in that, The system includes a Battery Management Unit (BMU), a Battery Junction Box (BJB), and multiple Cell Management Units (CMUs). The BMU includes a first MCU module, and a battery pressure monitoring sensor module, a high-voltage contactor driver module, a power management module, a CAN communication module, and a first daisy-chain communication module, all electrically connected to the first MCU module. The BJB includes a second MCU module, and an isolation measurement module and a second daisy-chain communication module, all electrically connected to the second MCU module. Each CMU includes a third MCU module, and a battery voltage acquisition module and a voltage balancing module, all electrically connected to the third MCU module. The BMU communicates with the BJB and each CMU via the first daisy-chain communication module. Each CMU is configured within a different battery pack and is used to collect cell data from the corresponding battery pack. The BJB is used to monitor the overall electrical parameters and high / low voltage isolation status of the battery system.

2. The system architecture according to claim 1, characterized in that, The power management module of the battery management unit and the first MCU module form a minimum working system to provide stable power supply for all modules of the battery management unit; the high-voltage contactor driver module has a reserved expansion interface for connecting the liquid cooling control components to realize the expanded control of the liquid cooling system.

3. The system architecture according to claim 1, characterized in that, The voltage balancing module of the battery cell management unit is directly connected to the battery voltage acquisition module. The battery voltage acquisition module transmits the cell voltage data to the third MCU module of the battery cell management unit. After receiving the balancing command from the battery management unit, the battery cell management unit controls the voltage balancing module to adjust the charging and discharging of cells with voltage deviations exceeding the range, so that the voltage of each cell tends to be consistent.

4. The system architecture according to claim 1, characterized in that, The isolation measurement module of the battery junction box is used to detect the insulation resistance value between the low-voltage circuit and the high-voltage circuit. When the insulation resistance value is lower than a preset threshold, the second MCU module of the battery junction box sends a fault signal to the battery management unit through the second daisy-chain communication module, and the battery management unit triggers the fault handling mechanism.

5. The system architecture according to claim 1, characterized in that, The CAN communication module of the battery management unit is used to establish bidirectional communication with the eVTOL vehicle controller, upload battery system status data, and receive charging, discharging, and thermal management commands issued by the vehicle controller.

6. A control method for a single BMU multi-battery pack parallel system architecture for eVTOL, implemented based on the system architecture of any one of claims 1-5, characterized in that, include: S1: System power-on initialization: The power management module of the BMU establishes the minimum working system, establishes communication with the BJB and each CMU through the first daisy-chain communication module and verifies the initial state, and triggers an alarm when there is an abnormality; S2: Charging control: The BMU controls the high-voltage contactor driver module to perform a pre-charging operation. After the pre-charging is completed, it switches to fast charging mode. At the same time, the CMU realizes cell voltage balancing. S3: Discharge control: The BMU controls the discharge circuit to conduct according to power demand, monitors the discharge current and cell status in real time, and adjusts the power supply circuit when abnormal. S4: Data monitoring and processing: BJB and each CMU continuously collect system parameters and cell data, upload them to BMU for summary analysis and feedback to the vehicle controller; S5: Safety and Temperature Management: The BMU monitors battery pressure to warn of heat loss risks and combines temperature data to regulate thermal management components and balance the temperature of each battery pack.

7. The control method according to claim 6, characterized in that, The temperature equalization control process in step S5 is as follows: the BMU calculates the temperature difference of the battery pack uploaded by each CMU. When the difference exceeds the preset equalization range, the heat exchanger is controlled to adjust the flow rate of the heat exchange medium flowing through each battery pack so that the temperature of each battery pack is maintained within the preset operating range.

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