A method and system for monitoring thermal runaway of a power battery and an electric vehicle

Abstract

The application discloses a thermal runaway monitoring method and system of a power battery and an electric vehicle. The method comprises the following steps: when the power vehicle is in a high-voltage power-on state, the battery management system takes power from the power battery pack through a DC-DC step-down converter to monitor the thermal runaway of the power battery pack in a power-off state; wherein the high-voltage end of the DC-DC step-down converter is connected to the total positive and total negative of the power battery pack, and the low-voltage end of the DC-DC step-down converter is connected to the battery management system; when the power vehicle is in a high-voltage power-on state, the battery management system takes power from the power battery pack through a high-voltage power distributor to monitor the thermal runaway of the power battery pack in a power-on state, and controls the switch control assembly inside the DC-DC step-down converter to automatically cut off the power supply line connected with the battery management system; wherein the high-voltage power distributor is connected to the total positive and total negative of the power battery pack and is controlled by the battery management system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power batteries, in particular to a thermal runaway monitoring method and system of a power battery and an electric vehicle. BACKGROUND

[0002] At present, electric vehicles have the advantages of zero tail gas emission and low energy cost. However, the thermal runaway accidents of power batteries of electric vehicles have caused obvious negative effects on the development of new energy vehicle industry, and have become an important factor restricting the development of electric vehicles.

[0003] In order to prevent the thermal runaway accidents of power batteries, the battery management system (BMS) is usually used to monitor and manage the state of the power battery.

[0004] The battery management system needs a power supply to maintain the operation of its electronic components, and can only monitor the thermal runaway state of the battery pack in the wake-up condition. When the system is powered off, the power battery no longer supplies power, and the monitoring of the battery management system is affected in many ways.

[0005] For example, most of the related equipment of the battery management system (data collector, temperature sensor, etc.) cannot work normally, the BMS cannot communicate normally with external equipment (such as the host computer monitoring system), some key electronic components in the BMS are limited in function in the powered-off state, which may cause the loss of battery state data, and when the system is powered on again, the battery management system cannot accurately obtain the complete state information of the previous battery, thereby affecting the effective monitoring and management of the battery.

[0006] Therefore, the existing technology has the problem that the battery management system is difficult to monitor the power battery all day long due to power supply problems. SUMMARY

[0007] In order to solve or partially solve the technical problem that the battery management system is difficult to monitor the power battery all day long due to power supply problems, the present application provides a thermal runaway monitoring method and system of a power battery and an electric vehicle. In the high-voltage powered-off state of the electric vehicle, the battery management system takes power from the power battery pack through a DC-DC step-down converter to monitor the thermal runaway of the power battery pack in the powered-off state. In the high-voltage powered-on state of the electric vehicle, the battery management system takes power from the power battery pack through a high-voltage power distributor to monitor the thermal runaway of the power battery pack in the powered-on state, and controls the switch control assembly inside the DC-DC step-down converter to automatically cut off the power supply line connected to the battery management system, so that the power battery can be monitored all day long, and the safety of the electric vehicle is ensured for 24 hours without interruption.

[0008] To solve the above technical problems, the first aspect of the present application discloses a thermal runaway monitoring method of a power battery, which comprises:

[0009] When the power automobile is in a high-voltage power-on state, the battery management system takes power from the power battery pack through a high-voltage power distributor to monitor the thermal runaway of the power battery pack in the power-on state, and controls a switch control assembly inside the DC-DC step-down converter to automatically cut off the power supply line connected with the battery management system; wherein the high-voltage power distributor is connected to the total positive and total negative of the power battery pack and is controlled by the battery management system.

[0010] When the power automobile is in a high-voltage power-on state, the battery management system takes power from the power battery pack through a high-voltage power distributor to monitor the thermal runaway of the power battery pack in the power-on state, and controls a switch control assembly inside the DC-DC step-down converter to automatically cut off the power supply line connected with the battery management system; wherein the high-voltage power distributor is connected to the total positive and total negative of the power battery pack and is controlled by the battery management system.

[0011] Optionally, after controlling the switch control assembly inside the DC-DC step-down converter to automatically cut off the power supply line connected with the battery management system, the method further comprises:

[0012] If the high-voltage power distributor fails, control the switch control assembly to connect the power supply line connected with the battery management system.

[0013] Optionally, the thermal runaway monitoring of the power battery pack in the power-off state specifically comprises:

[0014] Real-time collection of the operating state parameters of the power battery pack;

[0015] Uploading the operating state parameters to a cloud server, and receiving a thermal runaway early warning signal sent from the cloud server when it is detected that the operating state parameters meet the thermal runaway preset condition;

[0016] According to the thermal runaway early warning signal, an early warning processing strategy is triggered to be executed; wherein the early warning processing strategy comprises: sending thermal runaway early warning data to a vehicle controller, and / or controlling a main fuse located in the internal loop of the power battery pack to perform a fuse operation.

[0017] Optionally, the thermal runaway monitoring of the power battery pack in the power-on state specifically comprises:

[0018] Real-time collection of the operating state parameters of the power battery pack;

[0019] Detecting the operating state parameters by using the thermal runaway preset condition;

[0020] triggering an execution of a pre-warning processing strategy when the thermal runaway preset condition is met; wherein the pre-warning processing strategy comprises: sending thermal runaway pre-warning data to a vehicle controller, and / or controlling a main fuse located in an internal loop of the power battery pack to perform a fuse operation.

[0021] Optionally, the operating state parameter comprises one or more of a battery gas pressure rising rate, a battery gas pressure increase, a battery cell minimum voltage value, a battery temperature rising rate, a battery cell maximum temperature value, a battery cell maximum temperature difference value, a communication line fault signal of a battery management system, a voltage sampling short circuit fault signal, a thermistor failure signal, and a reverse wake-up signal of the battery management system.

[0022] The thermal runaway preset condition is a combination of one or more of the following conditions:

[0023] Condition A: the battery gas pressure rising rate is higher than a gas pressure rising rate threshold and the number of continuous times meets a standard;

[0024] Condition B: the battery gas pressure increase is greater than a thermal runaway gas pressure increase threshold and the number of continuous times meets a standard; wherein the battery gas pressure increase is a difference between a current collection gas pressure and an average value of previous N historical collection gas pressures at the current time;

[0025] Condition C: the battery cell minimum voltage value is less than or equal to a thermal runaway voltage pre-warning threshold;

[0026] Condition D: the battery temperature rising rate is higher than a temperature rising rate threshold and the duration meets a standard;

[0027] Condition E: the battery cell maximum temperature value is greater than or equal to a thermal runaway temperature pre-warning threshold and the duration meets a standard;

[0028] Condition F: the battery cell maximum temperature difference value is greater than or equal to a thermal runaway temperature difference pre-warning threshold and the duration meets a standard;

[0029] Condition G: a daisy chain communication line fault signal of the battery management system is reported and the duration meets a standard;

[0030] Condition H: a voltage sampling short circuit fault signal of the battery management system is reported and the duration meets a standard;

[0031] Condition I: a thermistor failure signal is reported and the number of failures meets a standard;

[0032] Condition J: a reverse wake-up signal of the battery management system is reported.

[0033] Optionally, the battery management system is connected to the main fuse through a fuse control assembly.

[0034] The control of the active fuse located in the internal loop of the power battery pack performs a fuse operation, specifically including:

[0035] The battery management system controls the active fuse to perform a fuse operation by using the fuse control component.

[0036] Optionally, the battery management system is connected with the active fuse through an auxiliary controller.

[0037] The control of the active fuse located in the internal loop of the power battery pack performs a fuse operation, specifically including:

[0038] The vehicle controller controls the auxiliary controller to generate a driving current to drive the active fuse to perform a fuse operation.

[0039] The driving current is blocked from flowing to the internal chip of the battery management system by using an anti-backflow component in the battery management system; wherein the anti-backflow component is designed in the line connecting the internal chip of the battery management system and the auxiliary controller.

[0040] In a second aspect of the present application, a thermal runaway monitoring system of a power battery is disclosed, and the system includes:

[0041] A power battery pack includes a plurality of battery monomers.

[0042] A DC-DC step-down converter is connected to the total positive and total negative of the power battery pack, and the low-voltage end is connected to the battery management system; the DC-DC step-down converter is used to take power from the power battery pack to supply power to the battery management system when the power vehicle is in a high-voltage power-on state.

[0043] A high-voltage power distributor is connected to the total positive and total negative of the power battery pack and is controlled by the battery management system, and is used to take power from the power battery pack to supply power to the battery management system when the power vehicle is in a high-voltage power-on state.

[0044] The battery management system is used to monitor the thermal runaway of the power battery pack in a power-off state when the power vehicle is in a high-voltage power-off state, and monitor the thermal runaway of the power battery pack in a power-on state when the power vehicle is in a high-voltage power-on state, and control the switch control component in the DC-DC step-down converter to automatically cut off the power supply line connected to the battery management system.

[0045] Optionally, if the high-voltage power distributor fails, the switch control component is controlled to connect the power supply line connected to the battery management system.

[0046] Optionally, the battery management system is specifically used for:

[0047] collecting, in real time, an operating state parameter of the power battery pack;

[0048] uploading the operating state parameter to a cloud server, and receiving a thermal runaway early warning signal sent from the cloud server when it is detected that the operating state parameter meets a thermal runaway preset condition;

[0049] triggering an early warning processing strategy according to the thermal runaway early warning signal; wherein the early warning processing strategy comprises sending thermal runaway early warning data to a vehicle controller, and / or controlling a fuse located in an internal loop of the power battery pack to perform a fuse operation.

[0050] Optionally, the battery management system is specifically used for:

[0051] collecting, in real time, an operating state parameter of the power battery pack;

[0052] detecting the operating state parameter using a thermal runaway preset condition;

[0053] triggering an early warning processing strategy when the thermal runaway preset condition is met; wherein the early warning processing strategy comprises sending thermal runaway early warning data to a vehicle controller, and / or controlling a fuse located in an internal loop of the power battery pack to perform a fuse operation.

[0054] Optionally, the operating state parameter comprises one or more of a battery gas pressure rising rate, a battery gas pressure increase, a battery monomer minimum voltage value, a battery temperature rising rate, a battery monomer maximum temperature value, a battery monomer maximum temperature difference value, a communication line fault signal of the battery management system, a voltage sampling short circuit fault signal, a thermistor failure signal, and a reverse wake-up signal of the battery management system.

[0055] The thermal runaway preset condition is a combination of one or more of the following conditions:

[0056] Condition A: the battery gas pressure rising rate is higher than a gas pressure rising rate threshold and the number of continuous times meets a standard;

[0057] Condition B: the battery gas pressure increase is greater than a thermal runaway gas pressure increase threshold and the number of continuous times meets a standard; wherein the battery gas pressure increase is the difference between the current collection gas pressure and the average value of the previous N historical collection gas pressures at the current time;

[0058] Condition C: the battery monomer minimum voltage value is less than or equal to a thermal runaway voltage early warning threshold;

[0059] Condition D: the battery temperature rising rate is higher than a temperature rising rate threshold and the duration meets a standard;

[0060] Condition E: the maximum temperature value of the battery cell is greater than or equal to a thermal runaway temperature warning threshold and the duration meets a standard;

[0061] Condition F: the maximum temperature difference value of the battery cell is greater than or equal to a thermal runaway temperature difference warning threshold and the duration meets a standard;

[0062] Condition G: a daisy chain communication line fault signal of the battery management system is reported and the duration meets a standard;

[0063] Condition H: a voltage sampling short circuit fault signal of the battery management system is reported and the duration meets a standard;

[0064] Condition I: a thermistor failure signal is reported and the number of failures meets a standard;

[0065] Condition J: a reverse wake-up signal of the battery management system is reported.

[0066] Optionally, the battery management system is connected with the active fuse through a fuse control component, for controlling the active fuse to perform a fuse operation by using the fuse control component.

[0067] Optionally, the battery management system is connected with the active fuse through an auxiliary controller, for triggering the auxiliary controller to generate a driving current to drive the active fuse to perform a fuse operation, and for blocking the driving current from flowing to an internal chip of the battery management system by using an anti-backflow component inside the battery management system, wherein the anti-backflow component is designed in a line connecting the internal chip of the battery management system and the auxiliary controller.

[0068] In a third aspect, the application discloses an electric vehicle, which comprises a memory, a battery management system and a computer program stored in the memory and capable of running on the battery management system, and the battery management system implements the steps of the method when executing the program.

[0069] By using one or more of the technical solutions of the application, the application has the following beneficial effects or advantages:

[0070] The application provides a thermal runaway monitoring method and system of a power battery and an electric vehicle.

[0071] The above description is only a summary of the technical scheme of the application. In order to make the technical means of the application more clearly understood and implemented according to the content of the specification, and in order to make the above and other purposes, features and advantages of the application more obvious and easy to understand, the following specific embodiments of the application are described. BRIEF DESCRIPTION OF DRAWINGS

[0072] Various other advantages and benefits will become apparent to those of ordinary skill in the art, upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of preferred embodiments, and are not meant to limit the present application. Furthermore, the same reference numerals are intended to denote the same components throughout the accompanying drawings. In the drawings:

[0073] Figure 1 Fig. 1 shows an internal structure diagram of a thermal runaway monitoring system of a power battery according to an embodiment of the application;

[0074] Figure 2 Fig. 3 shows a connection diagram of a step-down DC-DC and a battery management system according to an embodiment of the application;

[0075] Figure 3 Fig. 5 shows a design diagram of an anti-backflow assembly according to an embodiment of the application;

[0076] Figure 4 Fig. 6 shows a flowchart of a thermal runaway monitoring method of a power battery according to an embodiment of the application. DETAILED DESCRIPTION

[0077] Exemplary embodiments of the present application will be described hereinafter with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be embodied in various forms without being limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present application will be thoroughly and completely understood, and so that the scope of the present application will be completely conveyed to those skilled in the art.

[0078] In a first aspect, asFigure 1 As shown, the embodiment of the application first introduces the internal structure of the thermal runaway monitoring system of the power battery.

[0079] The thermal runaway monitoring system of the power battery of the application comprises: a battery management system, a power battery pack, a high-voltage power distribution unit (BDU, Battle Dress Uniform), and a DC-DC step-down converter (also referred to as: step-down DC-DC).

[0080] The power battery pack contains a plurality of battery monomers. Specifically, the plurality of battery monomers are connected in series to form the power battery pack, and the power battery pack has two connection ends of total positive and total negative.

[0081] The high-voltage end of the step-down DC-DC is connected to the total positive and total negative of the power battery pack, which can avoid being controlled by the high-voltage power distribution unit and its relay; the low-voltage end of the step-down DC-DC is connected to the battery management system.

[0082] The step-down DC-DC is used to take power from the power battery pack to supply power to the battery management system when the power automobile is in a high-voltage power-off state. Of course, the step-down DC-DC can also take power from the high-voltage battery pack all day long and convert it into 12V low voltage to supply the battery management system and other electrical appliances.

[0083] By installing the step-down DC-DC inside the power battery to supply power to the battery management system, the vehicle-mounted DC / DC and the low-voltage 12V storage battery originally connected to the battery management system can be cancelled, thereby avoiding the wake-up failure of the battery management system caused by the low power of the 12V storage battery.

[0084] In an optional embodiment, the step-down DC-DC is internally provided with a switch control component for automatically cutting off the power supply line connected to the battery management system when the power automobile is in a high-voltage power-on state, and conducting the power supply line connected to the battery management system when the power automobile is in a high-voltage power-off state. Optionally, if the high-voltage power distribution unit fails, the switch control component is controlled to connect the power supply line connected to the battery management system to supply power to the battery management system all day long. Specifically, the switch control component can be manually controlled by a technician to connect the power supply line connected to the battery management system. Of course, it can also automatically trigger the connection of the power supply line connected to the battery management system.

[0085] In an optional embodiment, the step-down DC-DC is internally provided with a high-voltage fuse component for cutting off the power supply line connected to the battery management system when a high-voltage fault occurs, thereby ensuring the safety of the vehicle.

[0086] The battery management system is used to monitor the thermal runaway of the power battery pack in a power-off state when the power automobile is in a high-voltage power-off state.

[0087] Referring toFigure 2 is a schematic diagram of the connection of the DC-DC step-down converter (also known as: step-down DC-DC) and the battery management system.

[0088] In Figure 2 , the total positive and total negative of the power battery pack are connected to the high-voltage end of the DC-DC step-down converter; the low-voltage end of the DC-DC step-down converter is connected to the battery management system.

[0089] When the electric vehicle is in a high-voltage power-off state (the vehicle is turned off and hibernated), the low-power monitoring mode is automatically activated. At this time, the connection line of the switch control component inside the step-down DC-DC to the battery management system is turned on, so that the step-down DC-DC takes power from the power battery pack and converts it into 12V power supply to the battery management system, supporting the battery management system to have a complete and seamless process chain from data acquisition, data storage, data transmission, analysis and calculation, instruction issuance and execution, and realizing all-round and all-weather online monitoring of the power battery and its related circuits in the high-voltage power-off state.

[0090] In this mode, the battery management system includes but is not limited to functions such as battery cell parameter acquisition, data upload, fault warning, instruction issuance, etc.

[0091] In addition, the step-down DC-DC is connected to the low-voltage electrical appliances on the vehicle side (including but not limited to the sentinel mode, OTA upgrade, data network connection, vehicle-mounted refrigerator and other equipment). The battery management system receives the power supply request of the low-voltage electrical appliances on the vehicle side, and controls the step-down DC-DC to take power from the power battery pack, convert it into low-voltage power, and distribute the power to the low-voltage electrical appliances on the vehicle side, supporting the operation of the low-voltage electrical appliances on the vehicle side. As can be seen, even in the high-voltage power-off state of the electric vehicle, through the design of the present application, the operation of the low-voltage electrical appliances on the vehicle side can also be supported.

[0092] When the electric vehicle is in a high-voltage power-on state (the vehicle is started and running), the battery management system automatically exits the low-power monitoring mode and activates all functions.

[0093] The high-voltage power distributor is connected to the total positive and total negative of the power battery pack and is controlled by the battery management system, and is used to take power from the power battery pack to supply power to the battery management system when the electric vehicle is in a high-voltage power-on state.

[0094] Specifically, the battery positive interface and the battery negative interface of the high-voltage power distributor are connected to the total positive (positive electrode of the power battery pack) and the total negative (negative electrode of the power battery pack) of the power battery pack, respectively. Through various circuits and elements inside the high-voltage power distributor, the distribution and control of the power of the power battery pack are realized, and the high-voltage power of the power battery pack is distributed to various high-voltage components of the vehicle, such as the motor controller and the charger, to ensure that these components can obtain stable and reliable power supply.

[0095] Further, the high-voltage power distributor is internally provided with a relay. Among them, one end of the total positive relay is connected to the total positive of the power battery pack, and the other end is connected to the related circuits such as the discharge positive electrode interface; one end of the total negative relay is connected to the total negative of the power battery pack, and the other end is connected to the related circuits such as the charging negative electrode interface and the discharge negative electrode interface. According to different operating modes of the vehicle, such as charging mode, discharging mode, pre-charging mode, etc., the opening and closing of the relay are controlled to realize the switching and management of the circuit, and to ensure that the charging and discharging process of the power battery pack can be carried out safely and efficiently.

[0096] The battery management system is used for monitoring the thermal runaway of the power battery pack in the high-voltage power-on state of the electric vehicle. Specifically, the battery management system is connected to each battery monomer or battery module in the power battery pack through a signal line to monitor the voltage, current, temperature and other parameters of the battery in real time. In addition, the battery management system is also connected to the control end of the relay in the high-voltage power distributor, and according to the state of the battery and the operating demand of the vehicle, the closing and opening of the relay are controlled to realize the management and protection of the charging and discharging process of the power battery pack.

[0097] In order to support the battery management system to execute the early warning processing strategy of thermal runaway on the hardware, the battery management system is connected to the active fuse through the fuse control component.

[0098] Specifically, the active fuse is usually connected in series in the power supply circuit of the power battery pack. When the power battery pack itself fails (such as internal short circuit), or the external load fails (such as motor controller short circuit) to cause the current to abnormally increase, such as reaching the early warning threshold, the active fuse will be fused to ensure the safety of the power battery.

[0099] In order to facilitate the control of the fusing time of the active fuse, the battery management system is connected to the active fuse through the fuse control component, and the fuse control component is used to control the active fuse to execute the fusing operation. Specifically, the fuse control component is an independent chip, and the battery management system generates a driving signal by controlling the fuse control component to drive the active fuse to execute the fusing operation.

[0100] Further, the fuse control component also has a feedback diagnosis function. Specifically, the fuse control component is also used to store the driving signal voltage when the driving signal voltage is higher than a set voltage (for example, 8V) and to feedback by using can communication.

[0101] In order to facilitate the control of the fusing time of the active fuse, the battery management system is connected to the active fuse through the auxiliary controller. The auxiliary controller has the function of triggering the fusing of the active fuse.

[0102] Specifically, the battery management system and the auxiliary controller (for example, the airbag controller ACU) can both trigger the active fuse to perform the fusing operation. In order to prevent the battery management system hardware from absorbing the auxiliary controller driving current, resulting in the inability to trigger the active fuse to perform the fusing operation of the power battery pack, the anti-backflow component is designed inside the battery management system. The anti-backflow component is designed in the line connected between the internal chip of the battery management system and the auxiliary controller.

[0103] Referring to Figure 3 , is a design schematic of the anti-backflow component.

[0104] When the power supply of the battery management system is disabled due to vehicle collision failure, and the power supply of the auxiliary controller is normally powered, the auxiliary controller current will backflow to the battery management system power supply through the circuit, resulting in abnormal voltage appearing across the chip IC of the battery management system, the diode D1 may be broken down, resulting in communication abnormalities or even failure of other electronic components under the same power supply.

[0105] In order to prevent the battery management system hardware from absorbing the auxiliary controller driving current, the diode D3 and the pull-up resistor R are added in the signal line between the auxiliary controller and the battery management system. The diode D3 is used to block the backflow current path. When the auxiliary controller outputs high level, the pull-up resistor R gives the chip IC of the battery management system high level; when the auxiliary controller outputs low level, the IC of the battery management system is clamped to low level by the diode D3. If the battery management system cannot be powered on, the high level output by the auxiliary controller cannot flow to the battery management system through the diode D3, thereby blocking the driving current from flowing to the battery management system.

[0106] The above is the hardware improvement designed by the present application to realize all-weather monitoring of the power battery. In the high-voltage state of the electric vehicle, the battery management system takes power from the power battery pack through the DC-DC step-down converter to monitor the thermal runaway of the power battery pack in the power-off state; in the high-voltage state of the power vehicle, the battery management system takes power from the power battery pack through the high-voltage distributor to monitor the thermal runaway of the power battery pack in the power-on state, so as to monitor the power battery all-weather, 24 hours uninterrupted to ensure the safety of the electric vehicle.

[0107] In a second aspect, based on the same inventive concept as the power battery thermal runaway monitoring system provided in the first aspect, the present application also provides a power battery thermal runaway monitoring method,

[0108] Referring to Figure 4 , the power battery thermal runaway monitoring method of the present application at least includes the following steps:

[0109] S401, when the power automobile is in a high-voltage power-off state, the battery management system takes power from the power battery pack through a DC-DC step-down converter to monitor the thermal runaway of the power battery pack in the power-off state.

[0110] The high-voltage end of the DC-DC step-down converter is connected to the total positive and total negative of the power battery pack, and the low-voltage end of the DC-DC step-down converter is connected to the battery management system. Through this design, the battery management system can be powered in the sleep state, so that the battery management system maintains all-weather monitoring of the power battery.

[0111] Specifically, in the process of monitoring the thermal runaway of the power battery pack in the power-off state, the following steps are specifically performed:

[0112] S4011, real-time acquisition of the running state parameters of the power battery pack.

[0113] The running state parameters include one or more of the following: battery gas pressure rising rate, battery gas pressure increase, battery monomer minimum voltage value, battery temperature rising rate, battery monomer maximum temperature value, battery monomer maximum temperature difference value, battery management system communication line fault signal, voltage sampling short circuit fault signal, thermistor failure signal, and battery management system reverse wake-up signal.

[0114] S4012, uploading the running state parameters to a cloud server, and receiving a thermal runaway early warning signal sent from the cloud server when it is detected that the running state parameters meet the thermal runaway preset condition.

[0115] In the high-voltage power-off state, the running state parameters are uploaded to the cloud server for analysis. It is worth noting that the running state parameters can be detected by the cloud or the vehicle using the thermal runaway preset condition. The checking process of the two is consistent, which will be described in detail later, and will not be repeated here.

[0116] Specifically, the vehicle communicates with the cloud server using wired data transmission communication or wireless data transmission communication to receive the thermal runaway early warning signal.

[0117] Wired data transmission communication includes but is not limited to using one or more of the following devices: switch, wired router, fiber transceiver, fiber cable, digital microwave device. Wireless data transmission communication includes but is not limited to using one or more of the following devices: wireless LAN, Bluetooth, network card, Zigbee. For example, the battery management system crosses the vehicle controller and uploads data to the cloud server in real time through the vehicle communication terminal T-BOX dedicated line.

[0118] S4013, triggering the early warning processing strategy according to the thermal runaway early warning signal. The early warning processing strategy includes sending thermal runaway early warning data to the vehicle controller and / or controlling the active fuse in the internal loop of the power battery pack to perform the fuse operation.

[0119] The above is the all-weather monitoring process of the high-voltage power-on state. The battery management system takes power from the internal voltage reduction DC-DC of the power battery to realize real-time data acquisition, storage, processing and transmission to the cloud server, so as to ensure that the cloud server synchronously analyzes and feeds back to the vehicle end in real time when thermal runaway occurs, reduces the calculation consumption of the vehicle end, and maximizes the protection of user life and property safety.

[0120] S402, when the power automobile is in a high-voltage power-on state, the battery management system takes power from the power battery pack through the high-voltage power distributor to monitor the thermal runaway of the power battery pack in the power-on state, and controls the switch control assembly inside the DC-DC voltage reduction converter to automatically cut off the power supply line connected with the battery management system.

[0121] The high-voltage power distributor is connected to the total positive and total negative of the power battery pack and is controlled by the battery management system. The execution logic of the high-voltage power distributor and the battery management system has been introduced in the foregoing hardware structure, and will not be described here.

[0122] In an optional embodiment, after controlling the switch control assembly inside the DC-DC voltage reduction converter to automatically cut off the power supply line connected with the battery management system, if the high-voltage power distributor fails, the switch control assembly is controlled to connect the power supply line connected with the battery management system.

[0123] In the process of monitoring the thermal runaway of the power battery pack in the power-on state, the following steps are included:

[0124] S4021, real-time acquisition of the running state parameters of the power battery pack.

[0125] The running state parameters include one or more of the following: battery gas pressure rising rate, battery gas pressure increase, battery monomer minimum voltage value, battery temperature rising rate, battery monomer maximum temperature value, battery monomer maximum temperature difference value, battery management system communication line fault signal, voltage sampling short circuit fault signal, thermistor failure signal, and battery management system reverse wake-up signal.

[0126] S4022, detecting the running state parameters by using the thermal runaway preset condition.

[0127] Specifically, the battery management system itself detects the running state parameters by using the thermal runaway preset condition, and the specific detection process will be introduced later, which will not be described here.

[0128] S4023, triggering the execution of the early warning processing strategy when the thermal runaway preset condition is met.

[0129] The early warning processing strategy includes sending thermal runaway early warning off data to the vehicle controller and / or controlling the active fuse in the power battery pack internal loop to perform a fuse operation.

[0130] It is worth noting that whether the electric vehicle is in a high-voltage power-on state or a high-voltage power-off state, the battery management system will monitor the operating state parameters of the power battery pack in real time, and store them in the storage medium after data format conversion for subsequent use.

[0131] Further, in order to save the computing power of the vehicle, whether the electric vehicle is in a high-voltage power-on state or a high-voltage power-off state, the operating state parameters can be uploaded to the cloud server, and the cloud server detects the operating state parameters using the thermal runaway preset condition, thereby saving the computing resources of the vehicle. Of course, if the electric vehicle is in a high-voltage power-on state, the operating state parameters can also be detected by the vehicle itself using the thermal runaway preset condition.

[0132] Specifically, the thermal runaway preset condition is one or a combination of the following:

[0133] Condition A: The battery gas pressure rise rate is higher than the gas pressure rise rate threshold and the duration meets the standard.

[0134] Specifically, the calculation method of the battery gas pressure rise rate is as follows:

[0135] Vn = (v j -v i ) / 0.5

[0136] Where Vn represents the battery gas pressure rise rate, n represents the number of statistics, v i represents the i-th battery gas pressure, v j represents the j-th battery gas pressure, and v i is calculated before v j , and j and i are separated by any battery gas pressure.

[0137] Specifically, after each battery gas pressure is counted, the battery gas pressure rise rate is calculated by the above formula.

[0138] Referring to Table 1, the gas pressure rise rate threshold v0 is set, and the gas pressure rise rate Vn is calculated in real time according to the above formula:

[0139] If the time series of the gas pressure signal reported by the gas pressure sensor is:

[0140] Table 1

[0141] Time (ms) 0 100 200 300 400 500 600 700 …… Battery gas pressure <![CDATA[v2]]> <![CDATA[v2]]> <![CDATA[v3]]> <![CDATA[v4]]> <![CDATA[v5]]> <![CDATA[v6]]> <![CDATA[v7]]> <![CDATA[v8]]> ……

[0142] According to Table 1, the calculated air pressure rising rates are v n =(v6-v1) / 0.5, (v7-v2) / 0.5, (v8-v3) / 0.5, ….

[0143] When Vn>V0, and the number of continuous times is greater than N times, condition A is met.

[0144] Condition B: the battery air pressure increase is greater than the thermal runaway air pressure increase threshold.

[0145] The battery air pressure increase is the difference between the current collected air pressure and the average of the previous N historical collected air pressures at the current time.

[0146] Specifically, a thermal runaway air pressure increase threshold ΔP0 is set, and the air pressure increase ΔP is calculated as follows:

[0147] The current air pressure value P n is collected. The collection air pressure interval time is 1 s, the current air pressure value is P1, the next air pressure value is P2, and so on.

[0148] The average of the previous N historical collected air pressures at the current time P0 is collected.

[0149] The battery air pressure increase is calculated as: ΔP=Pn-P0.

[0150] If ΔP>ΔP0 and the number of continuous times meets the standard, condition B is met.

[0151] Condition C: the minimum voltage value of the battery monomer is less than or equal to the thermal runaway voltage warning threshold.

[0152] Specifically, a thermal runaway voltage warning threshold U0 is set, and the minimum voltage value of the battery monomer is collected in real time as U min . If U min ≤U0, condition C is met.

[0153] Condition D: the battery temperature rising rate is higher than the temperature rising rate threshold and the duration meets the standard.

[0154] Specifically, the battery temperature rising rate is calculated as:

[0155] Kn=(T j -T i )

[0156] Wherein, Kn represents the battery temperature rising rate, n represents the number of statistics, T i represents the i-th battery temperature, T j represents the j-th battery temperature, and T i represents the k-th battery temperature, and Tj The battery temperature between j and i is calculated.

[0157] Specifically, after calculating the battery gas pressure, the battery temperature rising rate is calculated by the above formula.

[0158] Referring to Table 2, the temperature rising rate threshold k0 is set, and the battery temperature rising rate Kn is calculated according to the above formula:

[0159] If the time series of the gas pressure signal reported by the temperature sensor is:

[0160] Table 2

[0161] Time (ms) 0 200 400 600 800 1000 1200 1400 …… Battery temperature value T1 T2 T3 T4 T5 T6 T7 T8 ……

[0162] According to Table 2, the calculated temperature rising rate is Kn=(T6-T1), (T7-T2), (T8-T3), ….

[0163] When Kn>k0 and the duration is greater than N times, condition D is met.

[0164] Condition E: The maximum temperature value of the battery monomer is greater than or equal to the thermal runaway temperature warning threshold and the duration meets the standard.

[0165] Specifically, the thermal runaway temperature warning threshold T0 is set, and the maximum temperature value of the battery monomer is collected in real time as Tn,

[0166] If Tn≥T0 and the duration is greater than 2s, condition E is met.

[0167] Condition F: The maximum temperature difference value of the battery monomer is greater than or equal to the thermal runaway temperature difference warning threshold and the duration meets the standard.

[0168] Specifically, the thermal runaway temperature difference warning threshold AT0 is set, and the maximum temperature difference value of the battery monomer is calculated in real time:

[0169] ATn=Tn max -Tn min

[0170] Wherein, Tn max represents the highest temperature of the battery monomer with the maximum temperature difference, and Tn min is the lowest temperature of the battery monomer with the maximum temperature difference.

[0171] If ATn≥AT0 and the duration is greater than 2s, condition F is met.

[0172] Condition G: The daisy chain communication line fault signal of the battery management system is reported and the duration meets the standard.

[0173] For example, the daisy chain communication fault signal of the battery management system is reported, and the duration is ≥8s, which meets the condition G.

[0174] Condition H: the voltage sampling short circuit fault signal of the battery management system is reported and the duration meets the standard.

[0175] For example, the voltage sampling short circuit fault signal is reported, and the duration is ≥8s, which meets the condition H.

[0176] Condition I: the thermistor failure signal is reported and the number of failures meets the standard.

[0177] For example, the thermistor failure signal is reported, and the number of temperature sampling open circuits is ≥4, which meets the condition I.

[0178] Condition J: the reverse wake-up signal of the battery management system is reported. For example, the pressure sensor reverses the wake-up of the battery management system in the sleep state, which meets the condition J.

[0179] In the process of detecting the operating state parameters by using the thermal runaway preset condition, the thermal runaway preset condition can be obtained by combining the above-mentioned multiple conditions to detect the operating state parameters.

[0180] For example, the thermal runaway preset condition is:

[0181] Condition combination 1: (A||B||J) and (C||E||G||H||D||F) are met simultaneously within 10 minutes. “||” represents the relationship of or.

[0182] Condition combination 2: C and (D||E||F) are met simultaneously within 10 minutes.

[0183] Condition combination 3: after the D||E||F condition is met, the H condition is met within 10 minutes.

[0184] Condition combination 4: after the E||F condition is met, the G||I condition is met within 10 minutes.

[0185] If the operating state parameters meet any one of the above conditions, it means that the thermal runaway preset condition is met, and the warning processing strategy is triggered.

[0186] The warning processing strategy includes one or a combination of the following:

[0187] Warning processing strategy 1: sending thermal runaway warning related data to the vehicle controller. Specifically, the battery management system sends thermal runaway warning related data, such as alarm path and thermal runaway specific data, through network messages.

[0188] Early warning processing strategy 2: clear the early warning by the diagnostic service instruction, and prohibit the high voltage action and the hibernation wake-up action to restore the thermal runaway fault.

[0189] Early warning processing strategy 3: control the active fuse located in the internal loop of the power battery pack to perform the fuse operation.

[0190] As an optional implementation, since the battery management system is connected with the active fuse through the fuse control component, in the process of controlling the active fuse located in the internal loop of the power battery pack to perform the fuse operation, the battery management system drives the active fuse to perform the fuse operation by using the fuse control component.

[0191] Further, the battery management system is connected with the active fuse through the auxiliary controller. Both the battery management system and the auxiliary controller can control the fuse operation of the active fuse.

[0192] Specifically, the battery management system or the vehicle controller triggers the auxiliary controller to generate a driving current to drive the active fuse to perform the fuse operation. In order to prevent the battery management system hardware from absorbing the driving current of the auxiliary controller, resulting in the failure to trigger the active fuse to perform the fuse operation, the battery management system is internally designed with an anti-backflow component. The anti-backflow component is designed in the line connecting the internal chip of the battery management system and the auxiliary controller. After the auxiliary controller generates the driving current, the anti-backflow component in the battery management system is used to block the driving current from flowing to the internal chip of the battery management system.

[0193] In an optional implementation, if the running state parameter satisfies the thermal runaway condition combination containing condition J, it indicates that the electric vehicle has occurred thermal runaway in the hibernation state. After triggering the execution of the early warning processing strategy according to the thermal runaway early warning signal, the air pressure running state parameter of the previous n seconds satisfying the thermal runaway preset condition is transmitted to the battery management system, and the thermal runaway air pressure increase threshold, the thermal runaway voltage early warning threshold, and the air pressure rising rate threshold are latched for 5 seconds, so that the battery management system can obtain the relevant state information of the previous battery after the vehicle is powered on again, thereby realizing the effective monitoring and management of the battery.

[0194] In a third aspect, based on the same inventive concept as the thermal runaway monitoring method of the power battery provided in the first aspect, the embodiments of the present application also disclose an electric vehicle, which comprises a memory, a battery management system, and a computer program stored in the memory and capable of running on the battery management system, and the battery management system implements the steps of the method described in any of the preceding embodiments when executing the program.

[0195] Through one or more embodiments of the present application, the present application has the following advantages or benefits:

[0196] The application provides a thermal runaway monitoring method and system of a power battery and an electric vehicle. When the electric vehicle is in a high-voltage power-on state, a battery management system takes power from a power battery pack through a DC-DC step-down converter to monitor thermal runaway of the power battery pack in a power-off state; when the electric vehicle is in a high-voltage power-on state, the battery management system takes power from the power battery pack through a high-voltage power distributor to monitor thermal runaway of the power battery pack in a power-on state, so that the power battery can be monitored all day long, and the safety of the electric vehicle can be ensured for 24 hours without interruption.

[0197] Although preferred embodiments of the application have been described herein, those skilled in the art will readily devise numerous other variations of these preferred embodiments that, if not materially departing from the basic principles of the application, are to be considered within the scope of the application. Accordingly, it is intended that the appended claims be construed as including all such variations as fall within the scope of the application.

[0198] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A method of thermal runaway monitoring of a power cell, the method comprising: The method comprises: ​ When the electric vehicle is in a high-voltage power-off state, the battery management system takes power from the power battery pack through a DC-DC step-down converter to perform thermal runaway monitoring of the power battery pack in a power-off state; wherein the thermal runaway monitoring of the power battery pack in the power-off state specifically comprises: collecting operating state parameters of the power battery pack in real time; uploading the operating state parameters to a cloud server, and receiving a thermal runaway early warning signal sent from the cloud server when the operating state parameters are detected to meet thermal runaway preset conditions; triggering an early warning processing strategy according to the thermal runaway early warning signal; wherein the early warning processing strategy comprises: sending thermal runaway early warning data to a vehicle controller, and the battery management system using an auxiliary controller to control a main fuse located in an internal loop of the power battery pack to perform a fuse operation; wherein the battery management system is connected to the main fuse through the auxiliary controller, the battery management system triggers the auxiliary controller to generate a driving current to drive the main fuse to perform a fuse operation; using an anti-backflow component inside the battery management system to block the driving current from flowing to the internal chip of the battery management system; wherein the anti-backflow component is designed in the line connecting the internal chip of the battery management system and the auxiliary controller; the high-voltage end of the DC-DC step-down converter is connected to the total positive and total negative of the power battery pack, and the low-voltage end of the DC-DC step-down converter is connected to the battery management system; When the electric vehicle is in a high-voltage power-on state, the battery management system takes power from the power battery pack through a high-voltage power distributor to perform thermal runaway monitoring of the power battery pack in a power-on state, and controls a switch control component inside the DC-DC step-down converter to automatically cut off the power supply line connected to the battery management system; wherein the high-voltage power distributor is connected to the total positive and total negative of the power battery pack and is controlled by the battery management system.

2. The method of claim 1, wherein, After the control of the switch control component inside the DC-DC step-down converter to automatically cut off the power supply line connected to the battery management system, the method further comprises: If the high-voltage power distributor fails, control the switch control component to connect the power supply line connected to the battery management system.

3. The method of claim 1, wherein, The thermal runaway monitoring of the power battery pack in the power-on state specifically comprises: Collecting operating state parameters of the power battery pack in real time; Detecting the operating state parameters using thermal runaway preset conditions; Triggering an early warning processing strategy when the thermal runaway preset conditions are met; wherein the early warning processing strategy comprises: sending thermal runaway early warning data to a vehicle controller, and / or controlling a main fuse located in an internal loop of the power battery pack to perform a fuse operation.

4. The method of claim 1 or 3, wherein, The operating state parameters include one or more of a battery gas pressure rising rate, a battery gas pressure increase, a battery cell minimum voltage value, a battery temperature rising rate, a battery cell maximum temperature value, a battery cell maximum temperature difference value, a communication line fault signal of a battery management system, a voltage sampling short circuit fault signal, a thermistor failure signal, and a reverse wake-up signal of the battery management system; The thermal runaway preset condition is a combination of one or more of the following conditions: Condition A: the battery gas pressure rising rate is higher than a gas pressure rising rate threshold and the duration meets a standard; Condition B: the battery gas pressure increase is greater than a thermal runaway gas pressure increase threshold and the duration meets a standard; wherein the battery gas pressure increase is a difference between a current collection gas pressure and an average value of previous N historical collection gas pressures at the current time; Condition C: the battery cell minimum voltage value is less than or equal to a thermal runaway voltage warning threshold; Condition D: the battery temperature rising rate is higher than a temperature rising rate threshold and the duration meets a standard; Condition E: the battery cell maximum temperature value is greater than or equal to a thermal runaway temperature warning threshold and the duration meets a standard; Condition F: the battery cell maximum temperature difference value is greater than or equal to a thermal runaway temperature difference warning threshold and the duration meets a standard; Condition G: a daisy chain communication line fault signal of the battery management system is reported and the duration meets a standard; Condition H: a voltage sampling short circuit fault signal of the battery management system is reported and the duration meets a standard; Condition I: a thermistor failure signal is reported and the number of failures meets a standard; Condition J: a reverse wake-up signal of the battery management system is reported.

5. A thermal runaway monitoring system for a power cell, the system comprising: The system includes: a power battery pack including a plurality of battery cells; a direct-current-direct-current step-down converter connected to a total positive and a total negative of the power battery pack and having a low-voltage end connected to a battery management system; the direct-current-direct-current step-down converter is configured to supply power to the battery management system from the power battery pack when a power automobile is in a high-voltage power-on state; a high-voltage power distributor connected to the total positive and the total negative of the power battery pack and controlled by the battery management system, and configured to supply power to the battery management system from the power battery pack when the power automobile is in the high-voltage power-on state. The battery management system is configured to monitor thermal runaway of the power battery pack in a power-off state when the power automobile is in a high-voltage power-off state. The battery management system is specifically configured to: collect operating state parameters of the power battery pack in real time; upload the operating state parameters to a cloud server, and receive a thermal runaway early warning signal sent from the cloud server when the operating state parameters meet preset thermal runaway conditions; trigger an early warning processing strategy according to the thermal runaway early warning signal; the early warning processing strategy includes: sending thermal runaway early warning data to a vehicle controller, and controlling a main fuse located in an internal loop of the power battery pack to perform a fuse operation by using an auxiliary controller; the battery management system is connected to the main fuse through an auxiliary controller, and is configured to trigger the auxiliary controller to generate a driving current to drive the main fuse to perform a fuse operation; an anti-backflow component in the battery management system is configured to block the driving current from flowing to an internal chip of the battery management system; the anti-backflow component is designed in a line connected between the internal chip of the battery management system and the auxiliary controller; and the battery management system is configured to monitor thermal runaway of the power battery pack in a power-on state when the power automobile is in a high-voltage power-on state, and control a switch control component in the DC-DC voltage converter to automatically cut off a power supply line connected to the battery management system.

6. The system of claim 5, wherein, If the high-voltage power distributor fails, the switch control component is controlled to connect the power supply line connected to the battery management system.

7. An electric vehicle comprising a memory, a battery management system and a computer program stored on the memory and executable on the battery management system, characterized in that, The battery management system implements the steps of the method of any one of claims 1-4 when executing the program.

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