Electric aircraft power battery management system with fault isolation function

Abstract

The invention discloses an electric aircraft power battery management system with a fault isolation function, which comprises a series branch, the series branch comprises a plurality of battery modules connected in series, each battery module is connected in series with an isolation switch, and each battery module is connected in parallel with a bypass switch; the series branch is configured to be used for managing a battery module management unit of the battery module, and the isolating switch and the bypass switch are both controlled by the battery module management unit; the plurality of series branches are connected in parallel and converged on the high-voltage direct-current bus, and the series branches are connected with the high-voltage direct-current bus through the access switch; and the battery module management unit is connected with the main control unit through an internal data bus. The bypass switch circuit is added to the battery module in the battery pack, when the system detects that the voltage of the battery module is abnormal, the battery module can be bypassed, other battery modules can continue to work, and the safety of the battery system can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a power battery management system for an electric aircraft with a fault isolation function. Background Art

[0002] In recent years, the state has vigorously promoted the development of the low-altitude economy, and the low-altitude economy has become a typical representative of the country's strategic emerging industries and new quality productivity. As one of the typical representatives of the low-altitude economy industry - electric vertical take-off and landing aircraft (eVTOL: Electric Vertical Take-off and Landing) and its related supporting industries have developed rapidly. Similar to electric vehicles, the "three electric systems" are the three core subsystems of eVTOL. The eVTOL "three electric systems" refer to the power supply system (battery), electric drive system (motor), and electronic control system (flight control system) of the aircraft. ① Battery System: The energy storage unit of eVTOL, responsible for providing the electrical energy required by the aircraft. The battery system usually includes a battery pack, a battery management system (BMS), etc., which are used to monitor the battery state, manage the charging and discharging process, and ensure the safety and performance of the battery; ② Electric Drive System: Includes motors and controllers, which convert the electrical energy provided by the battery into mechanical energy, drive the rotors or propellers of the aircraft to rotate, and thus achieve vertical take-off and landing and hovering. The performance of the electric drive system directly affects the power performance and efficiency of eVTOL; ③ Flight Control System, responsible for receiving pilot commands or control signals from the autonomous flight system, managing the flight state of the aircraft, including attitude control, power distribution, navigation, and obstacle avoidance, etc. The flight control system is the core to ensure the safe and stable flight of eVTOL. These three systems rely on each other and work together to enable eVTOL to perform flight actions such as vertical take-off and landing, hovering, forward movement, and turning. The design and performance of the "three electric systems" have a crucial impact on the range, load capacity, safety, and economy of eVTOL.

[0003] Compared with electric vehicles, eVTOL has higher requirements for the reliability and safety of the battery system. Faults in the battery system can easily affect flight safety and even lead to catastrophic accidents such as plane crashes. Therefore, compared with the battery system of electric vehicles, the design of the eVTOL battery system should fully consider the monitoring of the health status of the battery pack and consider that the battery module unit has functions such as fault isolation and bypass. When the battery system encounters situations such as large overload impacts and short circuits, it has the function of bypassing the impacted module and bypassing the short-circuited battery module to avoid the expansion of faults and cause catastrophic consequences. In a large battery pack composed of multiple series-connected batteries, due to the inconsistency of single cells (such as voltage, capacity, internal resistance, etc.), the battery performance is prone to decay or even damage during long-term use. The existing battery management systems lack effective solutions for abnormal battery cells, often resulting in the entire battery pack being unable to work properly or having a shortened lifespan.

[0004] Although the existing battery management systems can monitor the battery status (such as voltage, current, temperature, etc.), when an abnormal single cell occurs, they often can only trigger an alarm or stop the system operation. This method not only affects the continuity of the system but also increases the maintenance and replacement costs. Therefore, there is an urgent need for a battery management system that can bypass abnormal single cells, improving the reliability and lifespan of the system while ensuring the normal operation of the battery pack. Summary of the Invention

[0005] To overcome the above defects, the present invention aims to provide a power battery management system for electric aircraft with a fault isolation function, which is a topology of a battery management system suitable for eVTOL high-voltage battery packs. A bypass switch circuit is added to the battery modules inside the battery pack. When the system detects abnormal voltage of a battery module, it can bypass it, and other battery modules can continue to work, significantly improving the safety of the battery system.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A power battery management system for electric aircraft with a fault isolation function includes a series branch. The series branch includes a plurality of serially connected battery modules. Each battery module is serially connected with a disconnect switch, and each battery module is paralleled with a bypass switch. A battery module management unit configured to manage the battery modules is provided in the series branch. The disconnect switch and the bypass switch are both controlled by the battery module management unit;

[0008] A plurality of series branches are paralleled and converge on a high-voltage DC bus. The series branch is connected to the high-voltage DC bus through an access switch;

[0009] The battery module management unit is connected to the main control unit through an internal data bus.

[0010] Preferably, the battery modules in the same series branch, the battery module management units, isolation switches, and bypass switches configured for them are encapsulated in the same battery pack.

[0011] Furthermore, a current sampling module is configured for the series branch, a voltage sampling module is configured for the battery module, a temperature detection module and an acceleration detection module are configured for the battery pack, and the current sampling module, voltage sampling module, temperature detection module, and acceleration detection module are all connected to the battery module management unit.

[0012] Preferably, the current sampling module includes a sampling resistor, the sampling resistor is connected in series in the series branch, and the sensing element of the temperature detection module is an NTC resistor.

[0013] Furthermore, a heating module is provided in the battery pack, the heating module is electrically heated, and the switch of the heating module is controlled by the main control unit.

[0014] Furthermore, the present invention further includes a charging control switch and a discharging control switch. The charging control switch is connected in series between the charging port and the high-voltage DC bus, and the discharging control switch is connected in series between the discharging port and the high-voltage DC bus. The charging control switch and the discharging control switch are both controlled by the main control unit.

[0015] Furthermore, the main control unit is connected to the flight control through a data bus.

[0016] Preferably, both the isolation switch and the bypass switch are MOS transistors.

[0017] Preferably, the battery module management unit collects current, voltage, temperature, and acceleration data in real time through the current sampling module, voltage sampling module, temperature detection module, and acceleration detection module, analyzes the data, and controls the closing or opening of the access switch, isolation switch, and bypass switch according to the analysis results.

[0018] Preferably, the main control unit collects and summarizes the working state information of each battery module management unit through an internal data bus, sends the collected information to the flight control through the data bus, and simultaneously executes the control instructions issued by the flight control for the charging control switch, discharging control switch, and heating control switch;

[0019] The main control unit monitors the working conditions of the battery modules in real time, and optimizes the battery performance, extends the battery life, and ensures safe operation through intelligent algorithms.

[0020] The present invention configures a set of solid-state switch combinations with mutually exclusive characteristics for each battery module of a battery pack to achieve series connection control and bypass control protection of the battery modules and prevent the expansion of faults. When the battery system is working, if a certain battery module has abnormal parameters, the disconnect switch in the switch combination is disconnected, and the bypass control switch is turned on to isolate the faulty battery module from the battery pack and form a bypass path, ensuring that other normal-functioning battery modules in the series circuit of the battery pack output normally. This can prevent the safety of the entire battery pack from being affected by the failure of the battery module and improve the reliability and safety of the battery system. In addition, a distributed acceleration sensor monitoring circuit is added to monitor the magnitude of the mechanical shock suffered by the battery pack in real time. When the shock received by the battery modules in a certain area is greater than the design limit of the battery pack, it can be isolated and bypassed through the solid-state switch combination with mutually exclusive characteristics to prevent faults such as short circuits in the battery modules caused by large shocks and continuous output leading to high temperature of the battery pack, resulting in serious consequences.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. The present invention can monitor the voltage and current characteristic parameters of each battery module in the battery system in real time and can judge its health status according to the characteristic parameters of the battery module.

[0023] 2. The present invention can achieve precise control of the charging and discharging of the battery module through the combination of the disconnect switch and the bypass switch according to the real-time parameters, prevent overcharging and over-discharging of the battery module, and extend the battery life.

[0024] 3. When a short-circuit fault occurs in the battery module, the combination of the disconnect switch and the bypass switch can be used to isolate and bypass the faulty battery module, prevent the expansion of the fault, and enable other battery modules connected in series in the series branch to work normally, which can improve the reliability and safety of the battery system.

[0025] 4. When some battery modules in the battery system are subjected to mechanical shocks that the battery system can withstand, the combination of the solid-state intelligent disconnect switch and the solid-state intelligent bypass switch can be used to isolate and bypass the impacted battery module, prevent the impacted battery module from discharging and short-circuiting, triggering system faults, and improve the safety of the battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the topology diagram of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0028] Embodiment 1

[0029] This embodiment discloses a power battery management system for electric aircraft with a fault isolation function, which is applicable to the power battery management of electric aircraft such as eVTOL, and can also be extended to the battery management systems of multi-electric, all-electric and electric model platforms, such as electric drones, unmanned vehicles, unmanned boats and underwater submersibles.

[0030] Specifically, as Figure 1 shown, this embodiment includes but is not limited to the following aspects:

[0031] Distributed battery management system architecture: The BMS master control unit and the battery module management unit BMU in the battery management system adopt a distributed system architecture. The BMS master control unit controls each battery module management unit through a distributed bus. Each battery module management unit manages a battery module combination formed by connecting battery modules in series with the smallest unit, realizing distributed real-time control of the battery module combination and the battery module.

[0032] Battery system health status management: The voltage sensors, current sensors, temperature sensors and acceleration sensors distributed in the battery system cooperate with the battery module management unit and the BMS master control unit to complete the monitoring and diagnosis of the real-time working status of the battery system, and can realize overcharge, over-discharge, overheat, over-shock protection, and can also realize functions such as isolation bypass of faulty battery modules.

[0033] The BMS topology of the battery management system includes a BMS master control unit, a charging control switch K in , a discharge control switch K out , a heating control switch, battery module management units BMU1-n, an access switch K 1～n , a sampling resistor R s1～sn , an isolation switch K 11～nn , a bypass switch K' 11～nn , temperature detection modules NTC1-n, acceleration detection modules g1-n, heating modules 1-n, a voltage acquisition module V 11～nn , battery modules B 11～nn .

[0034] The BMS master control unit is mainly responsible for supervising the working status of the entire system, communicating with the flight control VMC through a data bus, and communicating with the battery module management units BMU1-n through an internal data bus. The BMS master control unit is connected to the control ports of the heating control switch, the charging control switch K in and the discharge control switch K out , and can control the on and off of these switches.

[0035] The charging control switch K in acts as a charging switch. The charging control switch K inIts control port is connected to the BMS main control unit and is directly controlled by it.

[0036] Discharge control switch K out Functions as a discharge switch. Discharge control switch K out Its control port is connected to the BMS main control unit and is directly controlled by it.

[0037] The battery module management units BMU1 - n monitor the working status of each battery module. Information is exchanged with the main control unit BMS through the internal data bus. The battery module management units BMU1 - n are connected to the corresponding access switches K 1～n , isolation switches K 11～nn and bypass switches K' 11～nn at their control ports and can control the on - off of these switches. The battery module management units BMU1 - n are connected to the sampling resistors R s1～sn , temperature detection modules NTC 1～n , acceleration detection modules g 1～n and voltage acquisition modules V 11～nn at their sampling ports for collecting sensor, current, temperature, acceleration and voltage information.

[0038] Access switch K 1～n has its control port connected to the corresponding battery module management units BMU1 - n. One end of the load of access switch K 1～n is connected to the positive pole of the high - voltage DC bus, and the other end of the load is connected to the corresponding sampling resistor R s1～sn .

[0039] Sampling resistor R s1～sn has one end connected to the load ports of the corresponding battery module management units BMU1 - n and access switch K 1～n , and the other end connected to the load ports of the corresponding battery module management units BMU1 - n, isolation switch K 11～nn and bypass switch K' 11～nn .

[0040] Isolation switch K 11～nn has its control port connected to the corresponding battery module management units BMU1 - n. One end of the load of isolation switch K 11～nn is connected to the corresponding sampling resistor R s1～sn and bypass switch K' 11～nn at their ports, and the other end is connected to the corresponding battery module B 11～n1 and voltage acquisition module V 11～nnPort connection. The disconnect switch is used to control whether the battery module is connected to the series circuit. It can be combined with the bypass switch to achieve overcharge and over-discharge control of the battery module, remove the faulty battery module from the series-connected battery module combination, and form a bypass circuit without affecting the operation of other battery modules.

[0041] Bypass switch K' 11～nn The control port of is connected to the corresponding battery module management units BMU1~n. The bypass switch K' 11～nn One end of the load of is connected to the corresponding sampling resistor R s1～sn and the disconnect switch K 11～nn The port connection, and the other end is connected to the corresponding battery module B 11～n1 and the voltage acquisition module V 11～nn The other port connection. It is in parallel with the battery module. When it is turned on, it can bypass the battery module from the series-connected battery module combination. Cooperating with the disconnect switch, it can complete functions such as charge and discharge control and fault isolation bypass.

[0042] The sampling ports of the temperature detection modules NTC1~n are connected to the corresponding battery module management units BMU1~n.

[0043] The sampling ports of the acceleration detection modules g1~n are connected to the corresponding battery module management units BMU1~n.

[0044] Voltage acquisition module V 11～nn The sampling port of is connected to the corresponding battery module management units BMU1~n. The voltage acquisition module V 11～nn One end of the load of is connected to the corresponding disconnect switch K 11～nn and the battery module B 11～n1 The port connection, and the other end is connected to the corresponding battery module B 11～n1 and the bypass switch K' 11～nn The other port connection.

[0045] Battery module B 11～nn One end is connected to the corresponding disconnect switch K 11～nn and the voltage acquisition module V 11～nn The port connection, and the other end is connected to the corresponding voltage acquisition module V 11～nn The other port connection.

[0046] This embodiment adopts a three - level architecture design. The system monitors the battery pack in real - time, obtains the battery state, predicts the remaining battery capacity and battery health, and realizes the charge and discharge control of the battery pack. At the same time, in order to improve the service life and safety of the battery, the voltage, current, working temperature and acceleration of the battery module are detected in real - time. If it is judged that a certain battery module has abnormal data, the series - connected control switch in the switch combination is disconnected, and the bypass control switch is turned on to isolate the faulty battery module from the battery pack, and a bypass path is formed to ensure the normal output of other functional normal battery modules in the series circuit of the battery pack, which can prevent the safety of the entire battery pack from being affected by the battery module failure and improve the reliability and safety of the battery system.

[0047] Embodiment 2

[0048] Based on Embodiment 1, this embodiment further discloses the control strategy of this electric aircraft power battery management system as follows:

[0049] 1) The BMS main control unit is mainly responsible for supervising the working state of the entire system. The core working principle is based on the real - time monitoring of the battery state and intelligent algorithm processing to optimize battery performance, extend battery life and ensure safe operation. It collects and summarizes the working state information of each battery module management unit (BMU) through the internal data bus, and sends the collected information to the flight control (VMC) through the data bus for information interaction. At the same time, it executes the control instructions issued by the flight control (VMC) for the charge control switch, discharge control switch and heating control switch.

[0050] 2) Data acquisition: The battery module management unit (BMU) respectively collects current, temperature, acceleration and voltage data in real - time through the sampling resistor R sn , the temperature detection module NTC n , the acceleration detection module g n and the voltage acquisition module V nn .

[0051] 3) Data processing and state estimation: The battery module management unit (BMU) processes and analyzes the current, temperature, acceleration and voltage data collected in 2). It uses advanced algorithms to analyze the collected data, identify the battery state, and make corresponding decisions according to the preset strategy. These algorithms include state estimation algorithms such as the Kalman filter algorithm, which calculate battery state and health indicators such as state of charge (SOC), state of health (SOH), state of power (SOP), etc.

[0052] 4) Charge and discharge control: The battery module management unit (BMU) will make a comprehensive trade - off according to the current, temperature, acceleration and voltage data collected in 2) and combined with the battery state and health indicators obtained in 3), and through the corresponding access switch Kn Control the charging and discharging processes to ensure the safety and performance of the battery.

[0053] 5) Cell balancing: The Battery Management Unit (BMU) of the battery module determines if there are voltage differences between different cells in the battery pack based on the current, temperature, acceleration, and voltage data collected in 2). If so, the BMU will control the balance circuit inside the battery pack as needed to transfer charge from the high-voltage cell to the low-voltage cell to achieve balanced charging and discharging of the battery.

[0054] 6) Fault protection: Once the BMU detects abnormal conditions such as overvoltage, undervoltage, overcurrent, short circuit, overheating, or low temperature based on the current, temperature, acceleration, and voltage data collected in 2), the BMU will take protective measures by disconnecting the corresponding access switch Kn to ensure the safe operation of the battery system. At the same time, it will report alarm information to the main control unit of the BMS.

[0055] Fault isolation: The BMU of the battery module monitors and diagnoses the real-time working status of the battery system based on the temperature, acceleration, and voltage data collected in 2). For each battery module B 11～nn If a certain battery module B nn shows abnormal parameters such as overcharging, over-discharging, overheating, or over-shock, the BMU will disconnect the series-connected isolation switch Knn in the mutex switch combination and connect the bypass switch K'nn to isolate the faulty battery module from the battery pack and form a bypass path to ensure the normal output of other functional normal battery modules in the series circuit of the battery pack. This can prevent the safety of the entire battery pack from being affected by the failure of a battery module and improve the reliability and safety of the battery system.

[0056] The present invention discloses a battery management system topology applicable to an eVTOL high-voltage battery pack. By detecting the voltage, current, working temperature, and acceleration of the battery module, the working condition of the battery module is judged. By adding a switch circuit to each battery module inside the battery pack, the battery safety is increased. When the acceleration sensor detects a large overload impact or high temperature, the battery module is disconnected to improve safety. By adding a bypass switch circuit to the battery modules inside the battery pack, when the system detects abnormal voltage of a battery module, it can be bypassed and other battery modules can continue to work, significantly improving the safety of the battery system.

[0057] Of course, the present invention can also have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all fall within the protection scope of the appended claims of the present invention.

Claims

1. An electric aircraft power battery management system with fault isolation function, characterized in that: The invention comprises a series branch, wherein the series branch comprises a plurality of battery modules connected in series, each battery module is connected in series with an isolating switch, and each battery module is connected in parallel with a bypass switch; the series branch is configured with a battery module management unit for managing the battery modules, and the isolating switch and the bypass switch are both controlled by the battery module management unit; Several series branches are connected in parallel to the high-voltage DC bus, and the series branches are connected to the high-voltage DC bus via access switches; The battery module management unit is connected to the main control unit via an internal data bus.

2. The electric aircraft power battery management system with fault isolation function according to claim 1, characterized in that: The battery modules of the same series branch and their configured battery module management unit, isolating switch and bypass switch are packaged in the same battery pack.

3. The electric aircraft power battery management system with fault isolation function according to claim 2, characterized in that: The series branch is configured with a current sampling module, the battery module is configured with a voltage sampling module, the battery pack is configured with a temperature detection module and an acceleration detection module, and the current sampling module, voltage sampling module, temperature detection module and acceleration detection module are all connected to the battery module management unit.

4. The electric aircraft power battery management system with fault isolation function according to claim 3, characterized in that: The current sampling module comprises a sampling resistor, which is connected in series in a series branch. The sensing element of the temperature detection module is an NTC resistor.

5. The electric aircraft power battery management system with fault isolation function according to claim 3, characterized in that: The battery pack is provided with a heating module, the heating module is electrically heated, and the switch of the heating module is controlled by a main control unit.

6. The electric aircraft power battery management system with fault isolation function according to claim 5, characterized in that: It also includes a charging control switch and a discharging control switch. The charging control switch is connected in series between the charging port and the high-voltage DC bus, and the discharging control switch is connected in series between the discharging port and the high-voltage DC bus. Both the charging control switch and the discharging control switch are controlled by the main control unit.

7. The electric aircraft power battery management system with fault isolation function according to claim 1, characterized in that: The main control unit is connected to the flight control via a data bus.

8. The electric aircraft power battery management system with fault isolation function according to claim 1, characterized in that: The isolating switch and the bypass switch are both MOS tubes.

9. The electric aircraft power battery management system with fault isolation function according to claim 3, characterized in that: The battery module management unit collects current, voltage, temperature and acceleration data in real time through the current sampling module, voltage sampling module, temperature detection module and acceleration detection module, analyzes the data, and controls the access switch, isolation switch and bypass switch to close or open according to the analysis results.

10. The electric aircraft power battery management system with fault isolation function according to claim 6, characterized in that: The main control unit collects and summarizes the working status information of each battery module management unit through the internal data bus, and sends the collected information to the flight control through the data bus, and executes the control instructions of the charging control switch, the discharging control switch and the heating control switch issued by the flight control; The main control unit monitors the operating conditions of the battery modules in real time, and optimizes battery performance, extends battery life and ensures safe operation through intelligent algorithms.

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