Power-off control method and control device of electric vehicle and electric vehicle

Abstract

The invention discloses a power-off control method and device for an electric vehicle and the electric vehicle, and the method comprises the steps: judging whether the electric vehicle meets a power-off initiation condition at present or not, and the power-off initiation condition comprises the detection of a first preset vehicle fault or the reception of a power-off instruction sent by a vehicle management system; when the electric vehicle meets the power-off initiation condition, a power-off process corresponding to the power-off initiation condition is executed, the power-off process corresponding to the first preset vehicle fault is a fault power-off process, and the power-off process corresponding to the power-off instruction is a normal power-off process; and in the process of executing the power-off process, judging whether the battery system has a hardware fault or not, and recording the hardware fault. According to the method, power-off is carried out according to the normal power-off process in the normal state, power-off is carried out according to the fault power-off process when the serious vehicle fault is detected, and the hardware fault of the battery system is diagnosed in the power-off process, so that the safety of the power-off process of the electric vehicle is improved.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control technology, and more specifically, to a power-off control method and control device for an electric vehicle, and an electric vehicle. Background Art

[0002] Electric vehicles have increasingly become a new direction for the development of today's automotive technology. The energy source of electric vehicles comes from the electrical energy stored in the battery components, and the safety requirements for electric vehicles are getting higher and higher. In the initial stage, due to the lack of a deep understanding of the safety of new energy vehicles, the control and diagnosis functions during the power-off process were relatively simple to implement. When a vehicle fails, it will cause immeasurable losses to the safety of the entire vehicle and even the driver.

[0003] At present, the power-off process of electric vehicles is mainly to simply control the contactor to disconnect in a timed sequence, without considering abnormal power-off conditions. For example, when the vehicle collides or the battery component fails seriously, the entire vehicle needs to be powered off. In other words, the current power-off control scheme does not take into account both normal power-off and abnormal power-off. In addition, the current power-off control scheme lacks a fault diagnosis mechanism during the power-off process, and pays little attention to the operational safety of the entire system. Summary of the invention

[0004] A series of simplified concepts are introduced in the Summary of the Invention, which will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0005] In view of the shortcomings of the prior art, a first aspect of an embodiment of the present invention provides a power-off control method for an electric vehicle, the method comprising:

[0006] Determining whether the electric vehicle currently meets a power-off initiation condition, wherein the power-off initiation condition includes detecting a first preset vehicle fault or receiving a power-off instruction issued by a vehicle management system;

[0007] When the electric vehicle meets the power-off initiation condition, a power-off process corresponding to the power-off initiation condition is executed, wherein the power-off process corresponding to the first preset vehicle fault is a fault power-off process, and the power-off process corresponding to the power-off instruction is a normal power-off process;

[0008] During the execution of the power-off process, it is determined whether the battery system has a hardware fault, and if it is determined that the battery system has a hardware fault, the hardware fault is recorded.

[0009] In one embodiment, the battery system includes a battery assembly and a main positive contactor connected to the battery assembly, and determining whether there is a hardware fault in the battery system includes:

[0010] issuing a disconnection instruction to the main positive contactor;

[0011] After the disconnection instruction is issued, it is determined whether the main positive contactor is disconnected. If the main positive contactor is not disconnected, it is determined that a sticking fault exists in the main positive contactor.

[0012] In one embodiment, determining whether the main positive contactor is disconnected includes:

[0013] Obtaining the external terminal voltage of the main positive contactor;

[0014] If the external terminal voltage of the main positive contactor does not drop below a preset threshold within a first preset time after the disconnection instruction is issued, it is determined that the main positive contactor is not disconnected.

[0015] In one embodiment, the preset threshold is determined according to the voltage of the battery assembly.

[0016] In one embodiment, the battery system includes a battery assembly and a main negative contactor connected to the battery assembly, and determining whether there is a hardware fault in the battery system includes:

[0017] issuing a disconnection instruction to the main negative contactor;

[0018] After the disconnection instruction is issued, it is determined whether the main negative contactor is disconnected. If the main negative contactor is not disconnected, it is determined that the main negative contactor has a sticking fault.

[0019] In one embodiment, determining whether the main negative contactor is disconnected includes:

[0020] Determining whether the main negative contactor is disconnected by a feedback voltage outputted from a feedback terminal of a feedback circuit, wherein one end of the feedback circuit is connected to an outer end of the main negative contactor, and the other end is connected to a reference voltage terminal, the feedback circuit comprises a first resistor and a second resistor, and the feedback terminal is located between the first resistor and the second resistor;

[0021] If the feedback voltage is the reference voltage of the reference voltage terminal, it is determined that the main negative contactor is disconnected.

[0022] In one embodiment, the method further comprises: grading the first preset vehicle fault according to severity, wherein the higher the severity of the first preset vehicle fault, the higher the fault level;

[0023] The executing the power-off process corresponding to the power-off initiation reason includes: determining the time used to complete the power-off process according to the fault level of the first preset vehicle fault, wherein the higher the fault level, the shorter the time used to complete the power-off process.

[0024] In one embodiment, the vehicle fault further includes a second preset vehicle fault, the severity of the second preset vehicle fault being lower than the severity of the first preset vehicle fault;

[0025] The method further includes reducing the charge and discharge power of the battery system when the second preset vehicle fault is detected.

[0026] In one embodiment, recording the detected hardware failure includes:

[0027] A hardware fault code corresponding to the hardware fault is stored.

[0028] A second aspect of an embodiment of the present invention provides a power-off control device for an electric vehicle, the power-off control device comprising a memory and a processor, the memory storing a computer program run by the processor, and the computer program, when run by the processor, executes the power-off control method for the electric vehicle as described above.

[0029] A third aspect of an embodiment of the present invention provides an electric vehicle, wherein the electric vehicle includes the power-off control device as described above.

[0030] The power-off control method, control device and electric vehicle of the embodiment of the present invention are powered off according to the normal power-off process under normal conditions, and are powered off according to the fault power-off process when a serious vehicle fault is detected, and the hardware faults of the battery system are diagnosed during the power-off process, thereby improving the safety of the power-off process of the electric vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and other purposes, features and advantages of the present invention will become more apparent by describing the embodiments of the present invention in more detail in conjunction with the accompanying drawings. The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings, the same reference numerals generally represent the same components or steps.

[0032] Figure 1 is a schematic circuit diagram of an existing battery system;

[0033] Figure 2 is a schematic flow chart of a power-off control method for an electric vehicle according to an embodiment of the present invention;

[0034] Figure 3 is a system architecture diagram of a battery system according to an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of a method for determining the disconnection state of a main positive contactor and a main negative contactor according to an embodiment of the present invention;

[0036] Figure 5 A detailed flow chart of a power-off control method for an electric vehicle according to an embodiment of the present invention;

[0037] Figure 6 The figure is a schematic block diagram of a power-off control device for an electric vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present application more obvious, the example embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present application described in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0039] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features well known in the art are not described.

[0040] It should be understood that the present application can be implemented in different forms and should not be interpreted as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0041] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0042] In order to thoroughly understand the present application, a detailed structure will be proposed in the following description to illustrate the technical solution proposed by the present application. The optional embodiments of the present application are described in detail as follows, but in addition to these detailed descriptions, the present application may also have other implementation methods.

[0043] like Figure 1 The circuit architecture of the battery system of an electric vehicle. Generally, the power-off (i.e., high-voltage power-off) strategy is that when a power-off command for the battery system is received, the main positive contactor will be disconnected first, and then the main negative contactor will be disconnected. When the bus voltage received by the high-voltage load end of the whole vehicle reaches a certain threshold, it means that the power-off is completed. However, under the existing technical solutions, the power-off strategy does not take into account the abnormal power-off state. For example, when the vehicle collides or the battery component has a serious failure, the whole vehicle must perform a power-off operation. At this time, the whole vehicle needs to enter the power-off state from different paths. The current power-off control logic cannot take into account both normal power-off and abnormal power-off.

[0044] In addition, the current power-off control scheme does not fully judge the fault of the entire system during the power-off process, which will affect the next power-on operation. For example, during the operation of disconnecting the contactor, it is not judged whether the contactor is stuck, and contactor sticking means that there is abnormal high voltage connection. Therefore, if it is not judged whether the contactor is stuck, it means that the high-voltage components of the system are not properly judged; if there is a hardware failure in the system, the validity judgment cannot be performed normally at the next power-on, which will affect the customer's normal power-on experience.

[0045] In response to the above problems, an embodiment of the present invention proposes a power-off control method for an electric vehicle, which powers off according to the normal power-off process under normal conditions, and powers off according to the fault power-off process when a serious vehicle fault is detected, and diagnoses the hardware status of the battery system during the power-off process, thereby improving the safety of the electric vehicle's power-off process.

[0046] The following describes the power-off control method, control device and electric vehicle of the electric vehicle according to the embodiment of the present invention with reference to the accompanying drawings. Figure 2 , Figure 2 FIG. 2 is a schematic flow chart of a method 200 for controlling power-off of an electric vehicle according to an embodiment of the present invention. The method 200 for controlling power-off of an electric vehicle according to an embodiment of the present invention comprises:

[0047] In step S210, it is determined whether the electric vehicle currently meets a power-off initiation condition, wherein the power-off initiation condition includes detecting a first preset vehicle fault or receiving a power-off instruction issued by a vehicle management system;

[0048] In step S220, when the electric vehicle meets the power-off initiation condition, a power-off process corresponding to the power-off initiation condition is executed, wherein the power-off process corresponding to the first preset vehicle fault is a fault power-off process, and the power-off process corresponding to the power-off instruction is a normal power-off process;

[0049] In step S230, during the execution of the power-off process, it is determined whether there is a hardware fault in the battery system, and if it is determined that there is a hardware fault in the battery system, the hardware fault is recorded.

[0050] The power-off control method of the embodiment of the present invention can be executed by a BMS (Battery Management System). The connection relationship between the BMS and other components of the vehicle is as follows: Figure 3 As shown. Among them, BMS is integrated in the power battery pack, connected to the vehicle controller, on-board charger, fast charging socket, and the on-board charger is connected to the slow charging socket and other components. On the other hand, BMS connects the main positive contactor, main negative contactor and pre-charge contactor, and controls the battery to supply power to the high-voltage load of the vehicle. BMS takes into account the needs of various operating conditions and fault diagnosis, and thus conducts careful logical control and judgment of the entire power-off process.

[0051] Specifically, when the BMS needs to cooperate with the entire vehicle to execute the power-off of the entire vehicle, it first determines the power-off initiation conditions currently satisfied by the electric vehicle, and treats them differently according to the satisfied power-off initiation conditions, and executes the power-off process corresponding to the currently satisfied power-off initiation conditions.

[0052] Among them, the power-off initiation conditions that can lead to power-off include detecting a first preset vehicle fault, or receiving a power-off command issued by the vehicle management system. Among them, when the power-off process is executed due to the detection of the first preset vehicle fault, the executed power-off process is a fault power-off process. When the power-off process is executed due to the receipt of a power-off command issued by the vehicle management system, the executed power-off process is a normal power-off process. Exemplarily, when the first preset vehicle fault is detected, the BMS will prioritize the execution of the fault power-off process regardless of whether the power-off command issued by the vehicle management system is received. Only when the first preset vehicle fault is not diagnosed and the BMS receives a power-off command issued by the vehicle management system, the normal power-off process is executed.

[0053] Since there are many possible faults of a vehicle, only serious faults will trigger power-off, while minor faults do not need to trigger power-off, therefore, the vehicle fault can be first identified, and it can be determined whether the vehicle fault is a first preset vehicle fault, so as to determine whether to execute the fault power-off process. The first preset vehicle fault is a predefined serious vehicle fault.

[0054] For example, the types of vehicle faults can be divided into single-cell undervoltage fault, overvoltage fault, total voltage overvoltage fault, total voltage undervoltage fault, high-voltage interlock fault, insulation fault, etc. The first preset vehicle fault can be defined according to the fault type, for example, once a certain type of vehicle fault occurs, it is determined to be the first preset vehicle fault. The first preset vehicle fault can also be defined according to the severity of the fault. For example, the total voltage overvoltage fault is also the first preset vehicle fault only when the severity is high.

[0055] Furthermore, the first preset vehicle fault may be graded according to severity, wherein the higher the severity of the first preset vehicle fault, the higher the fault level. Accordingly, when executing the power-off process, the time taken for the power-off process is determined according to the fault level of the first preset vehicle fault, wherein the higher the fault level, the shorter the time taken for the power-off process.

[0056] In some embodiments, vehicle faults may be classified into the following five levels according to the severity of the faults:

[0057] Level 1 fault means that the vehicle has only a minor fault, but it does not affect the normal use of the vehicle, so the BMS does not need to perform a power-off operation;

[0058] A secondary fault means that the BMS should limit the charge and discharge power to 70% within 10 seconds after the fault is diagnosed, but there is no need to disconnect the contactor;

[0059] Level 3 fault means that the BMS should limit the charge and discharge power to 0% within 10 seconds after diagnosing the fault, but it does not need to disconnect the contactor;

[0060] Level 4 fault means that the BMS should limit the charge and discharge power to 0% and disconnect the contactor within 2 seconds after diagnosing the fault;

[0061] Level 5 fault means that the BMS should limit the charge and discharge power to 0% within 0.5s and disconnect the contactor synchronously after diagnosing the fault.

[0062] When a level 4 or level 5 vehicle fault is identified, it means that the BMS needs to be powered off. In other words, level 4 and level 5 vehicle faults are the first preset vehicle faults that can trigger the power-off process. Among them, if the fault level is level 4, it means that the vehicle fault is already serious and delayed power-off can be performed. If the fault level is level 5, it means that the severity has reached the highest level and the power must be turned off immediately.

[0063] Among them, level 4 faults include, for example, serious over- or under-voltage faults of battery cells, high-voltage interlock faults, and serious insulation faults, while level 5 faults include vehicle collision, vehicle fire, serious insulation faults, single cell voltages that are too high or too low to a certain extent, and power bus short circuits, etc. The same type of fault may be divided into four or five levels due to different degrees of severity. For example, a minor insulation fault can be handled as a level 4 fault, and a serious insulation fault can be handled as a level 5 fault.

[0064] Level 2 and level 3 faults can be defined as the second preset vehicle fault. When a level 2 or level 3 fault is identified, the contactor can be cut off under load to avoid contactor burnout by reducing the charge and discharge power. Specifically, by reducing the charge and discharge power, the current of the entire high-voltage circuit can be reduced, so that when the contactor needs to be disconnected, the current obtained on the contactor contacts is very small, so that the contactor will not be cut off under load, and the contactor can be well protected. At the same time, since level 2 and level 3 faults are not serious vehicle faults, there is no need to disconnect the main positive contactor and the main negative contactor.

[0065] As described above, the second preset vehicle fault can also be divided into multiple levels (such as level 2 fault and level 3 fault) according to the severity of the fault. The higher the severity, the higher the fault level. At the same time, the higher the fault level, the lower the target value of the charging and discharging power.

[0066] After a vehicle fault is identified, the corresponding DTC fault code can be stored. The DTC fault code indicates a hardware fault. Once a DTC fault code exists, the fault status will be reconfirmed during the next power-off process. The next power-off command will not be responded to until the fault is eliminated.

[0067] During the power-off process, the embodiment of the present invention detects the hardware fault of the battery system and records the detected hardware fault to ensure that the next power-on can be performed normally. The hardware fault of the battery system can be diagnosed during both the fault power-off process and the normal power-off process; or, since the fault power-off process itself indicates that the vehicle has a serious hardware fault, the battery system can be diagnosed only during the normal power-off process.

[0068] like Figure 3 As shown, the battery system at least includes a battery assembly and a main positive contactor and a main negative contactor connected to the battery assembly. If the contactor does not disconnect after a disconnection instruction of the main positive contactor or the main negative contactor is issued, it is determined that there is a hardware fault. Such hardware fault can be determined by the control instruction of the contactor and the actual disconnection of the contactor.

[0069] Exemplarily, determining whether the main positive contactor has a hardware fault includes: issuing a disconnection instruction to the main positive contactor; after issuing the disconnection instruction, determining whether the main positive contactor is disconnected, and if the main positive contactor should be disconnected but is not disconnected, determining that the main positive contactor has a sticking fault. At this time, the sticking fault of the main positive contactor can be reported, and the corresponding DTC fault code can be stored.

[0070] Among them, the step of determining whether the main positive contactor is disconnected includes: obtaining the external terminal voltage of the main positive contactor (i.e., LINK+ voltage); if the external terminal voltage of the main positive contactor does not drop below a preset threshold within a first preset time after the disconnection command is issued, it is determined that the main positive contactor is not disconnected.

[0071] Specifically, after the BMS issues an instruction to disconnect the main positive contactor, it can read back the LINK+ voltage at the load end of the main positive contactor, and the LINK+ voltage can be used to feedback whether the main positive contactor is unable to disconnect. For example, after the BMS issues an instruction to disconnect the main positive contactor, it can determine whether the LINK+ voltage will drop to 90% of the PACK voltage (i.e., the voltage of the battery assembly) after a delay of T1 time (e.g., 500ms). If this condition is not met within the specified time, it is determined that there is a sticking fault in the main positive contactor.

[0072] Since the high-voltage charge on the power bus may not be discharged quickly at the motor controller end of the vehicle, the voltage difference at both ends of the main positive contactor is limited to a lower level, causing the problem of false alarm. Therefore, the embodiment of the present invention determines the preset threshold value according to the PACK voltage. When it is detected that the voltage difference at both ends of the main positive contactor exceeds 10%, it is determined that the main positive contactor has been disconnected. Otherwise, it is considered that the main positive contactor has a sticking fault, and the main positive contactor is reported to be in a state of being unable to disconnect (stuck close). After confirming that the main positive contactor has been disconnected, the main positive contactor will not be reported as being unable to disconnect.

[0073] In addition, if the main positive contactor is disconnected, the LINK+ voltage is closer to the PACK- voltage than the PACK voltage is to the PACK- voltage. However, the premise of this assumption is that the high-voltage load end of the vehicle can discharge a certain degree of high-voltage charge after the BMS issues a command to disconnect the main positive contactor. Only after the discharge will the LINK+ voltage drop. Therefore, after judging that the main positive contactor is disconnected, it is also possible to judge whether the LINK+ voltage drops to a certain threshold within T2. ​​If the LINK+ voltage does not drop to a certain threshold, a high-voltage load end discharge timeout fault is reported and the corresponding DTC fault code is stored.

[0074] After the main positive contactor is disconnected, the main negative contactor needs to be disconnected. After the main negative contactor disconnection instruction is issued, it is detected whether the main negative contactor is disconnected in response to the disconnection instruction. If the main negative contactor is not disconnected, it is determined that there is a adhesion fault in the main negative contactor and the corresponding DTC fault code is stored. Only when it is confirmed that the main negative contactor is disconnected, it is determined that the contactor disconnection and the total voltage discharge are completed.

[0075] Among them, the disconnection state of the main negative contactor can be determined by direct detection. Figure 4 , which shows a schematic diagram of detecting the disconnection state of the main negative contactor. Specifically, whether the main negative contactor is disconnected can be judged by the feedback voltage output by the feedback end of the feedback circuit, wherein one end of the feedback circuit is connected to the outer end of the main negative contactor, and the other end is connected to the reference voltage end (for example, a reference voltage of 5V), and the feedback circuit includes a first resistor R1 and a second resistor R2, and the feedback end is located between the first resistor R1 and the second resistor R2.

[0076] according to Figure 4 In the feedback circuit shown, when the main negative contactor is disconnected, the voltage fed back by the feedback terminal is the reference voltage (5V) of the reference voltage terminal. Therefore, if an instruction to disconnect the main negative contactor is issued, the voltage fed back by the feedback terminal is still the divided voltage on the second resistor R2, indicating that the main negative contactor is not disconnected. Therefore, the state of the main negative contactor can be judged by performing a logical comparison between the feedback voltage and the control instruction of the main negative contactor.

[0077] Below, refer to Figure 5 The flowchart of FIG. 1 is used to exemplarily describe the power-off process of an embodiment of the present invention.

[0078] like Figure 5 As shown, first, if the first preset vehicle fault is identified, the fault power-off process is executed. If the first preset vehicle fault is a level 4 fault, the DTC fault code is stored, and the charge and discharge power is linearly reduced to 0 within 1 second. If the first preset vehicle fault is a level 5 fault, the DTC fault code is stored, and the charge and discharge power is immediately reduced to 0.

[0079] If the first preset vehicle fault is not identified and a vehicle power-off command is received, the available power is first reduced to below 5 kW within 3 seconds, and then the chargeable and dischargeable power is linearly reduced to 0 at a certain slope.

[0080] Next, a command to disconnect the main positive contactor is issued, and after T1 time, it is determined whether the LINK voltage is lower than 90% of the PACK voltage. If the LINK voltage is lower than 90% of the PACK voltage, it is determined that the main positive contactor has been disconnected, otherwise it is determined that the main positive contactor has a sticking fault, and the corresponding DTC fault code is stored.

[0081] If the main positive contactor is disconnected normally, it is determined whether the LINK voltage drops to a certain threshold (for example, 60V) within the T2 time. If so, it is determined that the high-voltage load end is discharged normally. Otherwise, a high-voltage load end discharge timeout fault is reported and the corresponding DTC fault code is stored.

[0082] After the high-voltage load end is discharged, a command to disconnect the main negative contactor is issued, and it is determined whether the main negative contactor is disconnected normally. If the main negative contactor is disconnected normally, the disconnection status of the main negative contactor is reported, and the hard-line wake-up source disappears. If the main negative contactor is not disconnected, a adhesion fault of the main negative contactor is reported, and the corresponding DTC fault code is stored.

[0083] To sum up, the power-off control method 200 of the electric vehicle in the embodiment of the present invention powers off according to the normal power-off process under normal conditions, and powers off according to the fault power-off process when a serious vehicle fault is detected, and diagnoses the hardware faults of the battery system during the power-off process, thereby improving the safety of the power-off process of the electric vehicle.

[0084] Another aspect of the present invention provides a power-off control device for an electric vehicle. Figure 6 6 is a schematic diagram of the structure of a power-off control device according to an exemplary embodiment of the present invention. The power-off control device 600 includes a memory 610 and a processor 620. The memory 610 stores a computer program executed by the processor 620. When the computer program is executed by the processor 620, the power-off control method 200 described above is executed. The power-off control device 600 of the electric vehicle in the embodiment of the present invention can be implemented as a BMS (Battery Management System).

[0085] Exemplarily, the memory 610 is used to store computer programs. The memory 610 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, application programs required for multiple functions, etc. In addition, the memory 610 may include a high-speed random access memory, and may also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card, a secure digital card, a flash memory card, a plurality of disk storage devices, a flash memory device, or other volatile solid-state storage devices.

[0086] The processor 620 can be implemented by software, hardware, firmware or a combination thereof, and can use a circuit, a single or multiple application specific integrated circuits (Application Specific Integrated Circuit, ASIC), a digital signal processor (Digital Signal Processor, DSP), a digital signal processing device (Digital Signal Processing Device, DSPD), a programmable logic device (Programmable Logic Device, PLD), a field programmable gate array (Field Programmable Gate Array, FPGA), a central processing unit (Central Processing Unit, CPU), a controller, a microcontroller, and at least one of a microprocessor, so that the device can execute some steps or all steps of the power-off control method 100 in each embodiment of the present application or any combination of the steps therein.

[0087] To achieve the above-mentioned purpose, an embodiment of the present invention further proposes a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the power-off control method described in the first aspect of the embodiment is implemented. Computer-readable storage media include, but are not limited to, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROMs), optical storage devices, magnetic storage devices, or any suitable combination of the above. In this document, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in combination with an instruction execution system, apparatus, or device.

[0088] The embodiment of the present invention further provides a computer program, wherein when the computer program is executed by a processor, the method for controlling power-off of an electric vehicle described in the embodiment of the first aspect is implemented.

[0089] The embodiment of the present invention further provides an electric vehicle, comprising a power-off control device 600 as described above. The power-off control device 600 is connected to a vehicle controller, an on-board charger, a fast charging socket, and the on-board charger is connected to a slow charging socket and other vehicle components. On the other hand, the power-off control device 600 is connected to a main positive contactor, a main negative contactor and a pre-charging contactor, and controls the battery assembly to supply power to the high-voltage load of the vehicle.

[0090] To summarize, the power-off control device, computer-readable storage medium, computer program, and electric vehicle of the embodiments of the present invention are powered off according to the normal power-off process under normal conditions, and are powered off according to the fault power-off process when a serious vehicle fault is detected, and the hardware faults of the battery system are diagnosed during the power-off process, thereby improving the safety of the power-off process of the electric vehicle.

[0091] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application thereto. Various changes and modifications may be made therein by one of ordinary skill in the art without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0092] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0093] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.

[0094] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0095] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.

[0096] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0097] In addition, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0098] The various component embodiments of the present application can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all functions of some modules according to the embodiments of the present application. The application can also be implemented as a device program (e.g., computer program and computer program product) for executing a part or all of the methods described herein. Such a program implementing the present application can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0099] It should be noted that the above embodiments illustrate rather than limit the present application, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets should not be constructed as a limitation to the claims. The present application may be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In a unit claim that lists several devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names.

[0100] The above is only a specific implementation method or an explanation of a specific implementation method of the present application, and the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for controlling power-off of an electric vehicle, characterized in that: The method comprises: Determining whether the electric vehicle currently meets a power-off initiation condition, wherein the power-off initiation condition includes detecting a first preset vehicle fault or receiving a power-off instruction issued by a vehicle management system; When the electric vehicle meets the power-off initiation condition, a power-off process corresponding to the power-off initiation condition is executed, wherein the power-off process corresponding to the first preset vehicle fault is a fault power-off process, and the power-off process corresponding to the power-off instruction is a normal power-off process; During the execution of the power-off process, it is determined whether the battery system has a hardware fault, and if it is determined that the battery system has a hardware fault, the hardware fault is recorded.

2. The method according to claim 1, characterized in that The battery system includes a battery assembly and a main positive contactor connected to the battery assembly, and the determining whether there is a hardware fault in the battery system includes: issuing a disconnection instruction to the main positive contactor; After the disconnection instruction is issued, it is determined whether the main positive contactor is disconnected. If the main positive contactor is not disconnected, it is determined that a sticking fault exists in the main positive contactor.

3. The method according to claim 2, characterized in that The determining whether the main positive contactor is disconnected comprises: Obtaining the external terminal voltage of the main positive contactor; If the external terminal voltage of the main positive contactor does not drop below a preset threshold within a first preset time after the disconnection instruction is issued, it is determined that the main positive contactor is not disconnected.

4. The method according to claim 3, characterized in that The preset threshold is determined according to the voltage of the battery assembly.

5. The method according to claim 1, characterized in that The battery system includes a battery assembly and a main negative contactor connected to the battery assembly, and the determining whether there is a hardware fault in the battery system includes: issuing a disconnection instruction to the main negative contactor; After the disconnection instruction is issued, it is determined whether the main negative contactor is disconnected. If the main negative contactor is not disconnected, it is determined that the main negative contactor has a sticking fault.

6. The method according to claim 5, characterized in that The determining whether the main negative contactor is disconnected comprises: Determining whether the main negative contactor is disconnected by a feedback voltage outputted from a feedback terminal of a feedback circuit, wherein one end of the feedback circuit is connected to an outer end of the main negative contactor, and the other end is connected to a reference voltage terminal, the feedback circuit comprises a first resistor and a second resistor, and the feedback terminal is located between the first resistor and the second resistor; If the feedback voltage is the reference voltage of the reference voltage terminal, it is determined that the main negative contactor is disconnected.

7. The method according to claim 1, characterized in that The method further includes: grading the first preset vehicle fault according to severity, wherein the higher the severity of the first preset vehicle fault, the higher the fault level; The executing the power-off process corresponding to the power-off initiation reason includes: determining the time used to complete the power-off process according to the fault level of the first preset vehicle fault, wherein the higher the fault level, the shorter the time used to complete the power-off process.

8. The method according to claim 1, characterized in that: The vehicle fault further includes a second preset vehicle fault, the severity of the second preset vehicle fault being lower than the severity of the first preset vehicle fault; The method further includes reducing the charge and discharge power of the battery system when the second preset vehicle fault is detected.

9. The method according to claim 1, characterized in that: The recording of the hardware failure includes: A hardware fault code corresponding to the hardware fault is stored.

10. A power-off control device for an electric vehicle, characterized in that: The power-off control device comprises a memory and a processor, wherein the memory stores a computer program executed by the processor, and when the computer program is executed by the processor, the power-off control method for an electric vehicle according to any one of claims 1 to 9 is executed.

11. An electric vehicle, characterized in that: The electric vehicle includes the power-off control device according to claim 10 .

Images