Electric vehicle power supply system, method and equipment and storage medium

Abstract

The invention relates to an electric vehicle power supply system, method and device and a storage medium. After a whole vehicle is powered off, a low-voltage power-on request sent by a main controller is received; and based on the low-voltage power-on request, the BMS controls conduction of at least two groups of MOS transistors of an internal battery management chip AFE, so that at least one battery cell in the high-voltage power battery supplies power to the low-voltage power utilization device. By means of the method, a traditional low-voltage storage battery is omitted, accessories such as a relay and a wire harness of the low-voltage storage battery are reduced, the manufacturing cost and weight of the whole vehicle are reduced, the endurance potential is improved, and when the whole vehicle is dormant, the battery cell energy of the high-voltage power battery is directly called, and the self-discharge loss of the low-voltage storage battery is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to an electric vehicle power supply system, method, device, and storage medium. Background Art

[0002] Currently, the low-voltage power supply system of electric vehicles generally uses a low-voltage battery as the power source to supply power to low-voltage electrical components. During normal operation, the high-voltage power battery is stepped down by a step-down DC-DC converter (Direct Current-to-Direct Current Converter, DCDC) and then connected in parallel with the low-voltage battery for power supply. The electrical components consume the energy stored in the high-voltage power battery. When the high-voltage system is not working, the low-voltage battery comes into play to supply power to the low-voltage electrical components. The low-voltage battery has a single application scenario, resulting in redundancy and waste in the low-voltage power supply system.

[0003] In related technologies, it is mostly a combination of relays and high-voltage power batteries. By controlling the opening and closing states of the relays, multiple battery cells of the power battery are multiplexed time-divisionally to achieve power supply from the power battery to the low-voltage power supply system, so as to eliminate the low-voltage battery. However, the combination of multiple relays and connecting wire harnesses may not necessarily be more advantageous in terms of weight and cost than independent low-voltage battery power supply. Summary of the Invention

[0004] One of the objectives of the present invention is to provide an electric vehicle power supply system, method, device, vehicle, and storage medium, which can eliminate the low-voltage battery while reducing the usage of relays and wire harnesses, avoid redundancy and waste in the low-voltage power supply system, and reduce the weight and cost of the entire vehicle.

[0005] To achieve the above objective, the technical solution adopted by the present invention is as follows: An electric vehicle power supply system includes: a high-voltage power battery, a step-down DCDC, a BMS, a vehicle controller, and low-voltage electrical components; The high-voltage power battery is connected to the input end of the step-down DCDC, the high-voltage power battery is connected to the BMS, the low-voltage electrical components are connected in parallel to the output end of the step-down DCDC and the output end of the BMS, and the vehicle controller is communicatively connected to the step-down DCDC and the BMS; The BMS internally integrates an AFE, and the AFE internally integrates multiple groups of MOS transistors; The high-voltage power battery integrates multiple series-connected battery cells; Each battery cell is connected to a group of MOS transistors; The BMS is used to control at least two groups of MOS transistors inside the AFE to conduct, so that at least one battery cell in the high-voltage power battery supplies power to the low-voltage electrical components.

[0006] In a possible implementation manner, each group of MOS transistors includes a high-side MOS transistor and a low-side MOS transistor; The first end of the high-side MOS transistor is connected to the positive electrode of the corresponding battery cell, and the second end of the high-side MOS transistor is connected to the positive electrode of the low-voltage electrical device; The first end of the low-side MOS transistor is connected to the negative electrode of the corresponding battery cell, and the second end of the low-side MOS transistor is connected to the negative electrode of the low-voltage electrical device.

[0007] In a possible implementation manner, the BMS is further configured to automatically switch to the backup battery cell group and report a fault code to the vehicle controller when the AFE detects overcurrent or short circuit of the MOS transistor.

[0008] In a possible implementation manner, the step-down DCDC is configured to step down the high voltage output by the high-voltage power battery and supply power to the low-voltage electrical device.

[0009] An electric vehicle power supply method, which applies the BMS in the electric vehicle power supply system described in any one of the above, the method includes: After the vehicle is powered off, receive a low-voltage power-on request sent by the main controller; Based on the low-voltage power-on request, the BMS controls at least two groups of MOS transistors of the internal battery management chip AFE to conduct, so that at least one battery cell in the high-voltage power battery supplies power to the low-voltage electrical device.

[0010] In a possible implementation manner, the method further includes: After the BMS wakes up and starts the battery cell inspection function, send a sleep feedback message to the main controller, so that the main controller controls the step-down DCDC to stop power supply.

[0011] In a possible implementation manner, the method further includes: After the vehicle is powered on, receive a power supply switching instruction sent by the main controller; Based on the power supply switching instruction, disconnect the conducting MOS transistors in the AFE and stop supplying power to the low-voltage electrical device.

[0012] In a possible implementation manner, the method further includes: After the BMS enables the battery cell inspection function, control the AFE to detect the voltage of the currently powered battery cell at a preset period; When the voltage of the currently powered battery cell is lower than a preset discharge cut-off threshold, the AFE triggers a hardware interrupt to wake up the BMS; After the BMS collects the voltages of all the high-voltage power batteries, screen the battery cell group with the highest voltage priority as the next group of powered battery cells; The BMS controls the AFE to disconnect the current power supply circuit and turn on the MOS transistors corresponding to the next set of power supply battery cells, so that the next set of power supply battery cells supply power to the low-voltage electrical appliances.

[0013] A BMS includes: a storage unit, a processing unit; The storage unit stores computer-executable instructions; The processing unit executes the computer-executable instructions stored in the storage unit, so that the processing unit executes the method described in any one of the above.

[0014] A computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, they are used to implement the method described in any one of the above.

[0015] A computer program product includes a computer program, and when the computer program is executed by a processor, it implements the method described in any one of the above.

[0016] Advantages of the present invention: In this solution, the high-voltage power battery is respectively connected to the step-down DCDC and the BMS. After the step-down DCDC and the BMS are connected in parallel, they supply power to the low-voltage electrical appliances. The vehicle controller coordinates the switching of the power supply mode. When the vehicle is running, the step-down DCDC supplies power after stepping down the voltage. When the vehicle is in sleep mode, the BMS controls the battery cells directly to supply power to the low-voltage system through its integrated AFE. During the start / stop phase, the vehicle controller schedules the switching of the power supply circuit. By canceling the low-voltage battery, weight reduction and cost reduction are achieved. The dual-path power supply redundancy design improves the system reliability. The dynamic battery cell switching and balancing management extend the service life of the power battery. The low-power sleep mode optimizes the standby endurance, effectively solving the problems of redundant waste, high self-discharge, and short service life in traditional low-voltage power supply. Description of the drawings

[0017] Figure 1 It is the architecture diagram of the electric vehicle power supply system provided by this application; Figure 2 It is the internal structure diagram of the high-voltage power battery provided by this application; Figure 3 It is the schematic flow chart of the electric vehicle power supply method provided by the embodiment of this application Figure 1 ; Figure 4 It is the schematic flow chart of the electric vehicle power supply method provided by the embodiment of this application Figure 2 ; Figure 5 It is the schematic flow chart of the electric vehicle power supply method provided by the embodiment of this application Figure 3 ; Figure 6 It is the schematic diagram of the BMS structure provided by the embodiment of this application. Detailed implementation manners

[0018] The following will illustrate the implementation manners of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention rather than limiting the protection scope of the present invention.

[0019] It should be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of the present invention. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0020] Figure 1 is the architecture diagram of the electric vehicle power supply system provided for this application, as Figure 1As shown in the figure, the system includes 1 - high - voltage power battery, 2 - step - down DCDC, 3 - BMS, 4 - low - voltage electrical appliances, and 5 - VCU (vehicle control unit). The 1 - high - voltage power battery is connected to the input end of the 2 - step - down DCDC through a high - voltage power bus, which is used to transmit the high - voltage electricity generated by the 1 - high - voltage power battery. Another connection line between the 1 - high - voltage power battery and the 2 - step - down DCDC in the figure is used to transmit control signals, such as the status information fed back by the 2 - step - down DCDC to the 1 - high - voltage power battery, etc. The 1 - high - voltage power battery is connected to the 3 - BMS. Among the two connection lines between the 1 - high - voltage power battery and the 3 - BMS in the figure, one is used for the 1 - high - voltage power battery to transmit information such as the voltage and temperature of the battery cells to the 3 - BMS, and the other connection is used for the 3 - BMS to transmit the drive signals for the control components related to the battery cells to achieve the control operation of the battery cells. The 4 - low - voltage electrical appliances are connected in parallel to the output end of the 2 - step - down DCDC and the output end of the 3 - BMS through low - voltage power lines. Among them, for the connection line between the 2 - step - down DCDC and the 4 - low - voltage electrical appliances, one is used for the 2 - step - down DCDC to convert high - voltage electricity into low - voltage electricity and supply power to the 4 - low - voltage electrical appliances through this line to meet their working voltage requirements, and the other connection line is used to return the current passing through the 4 - low - voltage electrical appliances to the 2 - step - down DCDC to form a complete current path. For the two connection lines between the 3 - BMS and the 4 - low - voltage electrical appliances, one is used for the 3 - BMS to control the battery cells through internal AFE chips, etc., draw out the electrical energy of the battery cells, and supply power to the 4 - low - voltage electrical appliances through this line. The other is also for forming a current loop, so that the current drawn from the battery cells can return to the battery cell loop controlled by the 3 - BMS through this return line after passing through the 4 - low - voltage electrical appliances, ensuring the integrity of the current path when the 3 - BMS controls the battery cells to supply power to the 4 - low - voltage electrical appliances. The 5 - VCU is communicatively connected to the 2 - step - down DCDC and the 3 - BMS.

[0021] Among them, an AFE is integrated inside the BMS, and multiple groups of MOS transistors are integrated inside the AFE. Figure 2 The internal structure diagram of the high - voltage power battery provided by this application is as Figure 2 shown. The 1 - high - voltage power battery integrates multiple series - connected battery cells.

[0022] Each battery cell is connected to a group of MOS transistors. Optionally, each group of MOS transistors includes a high - side MOS transistor and a low - side MOS transistor. The first end of the high - side MOS transistor is connected to the positive electrode of the corresponding battery cell, the second end of the high - side MOS transistor is connected to the positive electrode of the low - voltage electrical appliance, the first end of the low - side MOS transistor is connected to the negative electrode of the corresponding battery cell, and the second end of the low - side MOS transistor is connected to the negative electrode of the low - voltage electrical appliance.

[0023] In a possible implementation, the 4 low-voltage electrical devices are simultaneously connected to the output terminals of the 2 step-down DCDCs and the output terminals of the 3 BMSs, forming a dual-path parallel power supply topology of "DCDC main supply + BMS standby".

[0024] Specifically, the 1 high-voltage power battery is connected to the AFE inside the 3 BMS through the cell sampling harness and the MOS drive line to realize cell state monitoring and power supply path control.

[0025] The 5 VCU is connected to the communication interface of the 3 BMS through the CAN bus / hardwired enable signal to send control instructions such as "low-voltage power-on request" and "power supply switching instruction" (such as triggering the BMS to start AFE power supply when the vehicle is powered off); The 5 VCU is connected to the communication interface of the 2 step-down DCDCs through the CAN bus / hardwired enable signal to send control instructions such as "wake up DCDC" and "stop DCDC" (such as waking up the DCDC to resume power supply when the vehicle starts); The 5 VCU receives status signals such as "AFE power supply stable" and "abnormal cell voltage" fed back by the 3 BMS through the CAN bus to realize closed-loop control.

[0026] The 3 BMS receives the control instructions from the 5 VCU and triggers the cell switching logic of the AFE chip; The 3 BMS feeds back status signals such as "AFE power supply stable" and "cell voltage threshold warning" to the 5 VCU to cooperate with the 5 VCU to complete the power supply mode switching; The AFE chip and the cells of the 1 high-voltage power battery interact data and control signals in real time through the sampling line (voltage / temperature) + MOS drive line (switch control).

[0027] The 2 step-down DCDCs receive the wake-up / stop instructions from the 5 VCU and control their own start and stop; The 2 step-down DCDCs feed back status signals such as "DCDC output voltage stable" and "DCDC fault" to the 5 VCU to assist the 5 VCU in judging the power supply safety.

[0028] Figure 3 Schematic diagram of the power supply method for the electric vehicle provided by the embodiment of the present application Figure 1 , as Figure 3 shown, this method should be used in the BMS of the aforementioned electric vehicle power supply system. This method mainly includes: S301: After the vehicle is powered off, receive the low-voltage power-on request sent by the main controller.

[0029] In this step, when the electric vehicle stops working, the vehicle controller responds to the vehicle power-off signal. After controlling most controllers to power off, the traditional solution relies on an independent low-voltage battery (such as a lead-acid battery) to maintain the power supply for low-voltage loads (anti-theft system, T-BOX, door controller, etc.). However, the low-voltage battery has inherent defects such as serious self-discharge. In this step, the vehicle control dominates the power-off timing. First, the high-voltage circuit is safely disconnected (the main relay of the high-voltage power battery is cut off to ensure the safety of the high-voltage side), and then the BMS is triggered to start the "direct supply of low voltage by battery cells" mode, replacing the traditional low-voltage battery with the battery cells of the high-voltage power battery, eliminating the defects of the low-voltage battery from the root cause.

[0030] Specifically, the main controller first turns off non-essential high-voltage loads (such as the drive motor, air-conditioning compressor), and disconnects the high-voltage main relay of the high-voltage power battery (which is a conventional safety design of the high-voltage circuit and is not explicitly marked in the attached drawings), cutting off the external power supply of the high-voltage power bus, and only retaining the low-voltage control power supply of the BMS. After the high-voltage circuit is safely powered off, the vehicle controller sends a "low-voltage power-on request" to the BMS through the CAN bus or a hard-wired enable signal (which can be defined as a dedicated CAN message, such as frame ID 0x123, and the data field contains a request flag bit).

[0031] Among them, the BMS is in the "low-power standby for wake-up" state during the vehicle power-off stage (only maintaining the operation of the communication module). When detecting the "low-voltage power-on request" from the vehicle controller, it activates the internal control logic to prepare for the MOS tube control of the subsequent AFE chip.

[0032] S302: Based on the low-voltage power-on request, the BMS controls at least two groups of MOS tubes of the internal battery management chip AFE to conduct, so that at least one battery cell in the high-voltage power battery supplies power to the low-voltage electrical appliances.

[0033] In this step, in the traditional solution, the low-voltage load is only powered by a single path of "high-voltage power battery → DCDC → low-voltage load" (when driving) or "low-voltage battery → low-voltage load" (after DCDC sleeps). In order to cancel the low-voltage battery and its accessories and achieve cost reduction and weight reduction, after DCDC sleeps, the battery cells of the high-voltage power battery directly supply power to the low-voltage load, completely eliminating the independent low-voltage battery.

[0034] Specifically, after the BMS receives the low-voltage power-on request sent by the vehicle controller, it realizes the "direct supply of low voltage by high-voltage power battery cells to low-voltage load" through three steps: battery cell group selection → MOS tube conduction → power supply loop establishment.

[0035] The BMS pre-stores the number of battery cells in the high-voltage power battery for electric vehicles (e.g., 10 cells in series) and the nominal voltage of each cell (e.g., 3.7V ternary lithium), and automatically calculates the number of cells in series that meet the low-voltage system (e.g., for a 12V system, 3 to 4 cells in series are required, 3.7V×3 = 11.1V≈12V, taking advantage of the voltage fluctuation tolerance of the cells or an internal micro-voltage regulator).

[0036] Specific cell selection rules may include: cells in the "middle voltage range" (avoiding fully charged / discharged cells to reduce the equalization pressure); or the cell group with the least number of historical discharge times (equalizing the cycle life of each cell).

[0037] The BMS sends instructions to the internal AFE. Each cell in the AFE corresponds to a group of high-side MOS transistors (controlling the positive electrode of the cell → the positive electrode of the low voltage) and low-side MOS transistors (controlling the negative electrode of the cell → the negative electrode of the low voltage). Taking "selecting the 3rd and 6th cells in series for power supply" as an example: Control the high-side MOS transistor of the 3rd cell to conduct, so that its positive electrode is connected to the positive bus of the low-voltage electrical device. Control the low-side MOS transistor of the 6th cell to conduct, so that its negative electrode is connected to the negative bus of the low-voltage electrical device. After the two groups of MOS transistors conduct, the series voltage of the 3rd to 6th (a total of 4 cells) cells (3.7V×4 = 14.8V, if 12V is required, it is regulated by the internal voltage regulator of the AFE or directly adapted to the load voltage tolerance range) directly supplies power to the low-voltage electrical device.

[0038] The electric vehicle power supply method provided by this application, after the vehicle is powered off, receives a low-voltage power-on request sent by the main controller. Based on the low-voltage power-on request, the BMS controls at least two groups of MOS transistors in the internal battery management chip AFE to conduct, so that at least one cell in the high-voltage power battery supplies power to the low-voltage electrical device. By the above method, the traditional low-voltage battery is cancelled, and the accessory components such as the relay and wiring harness of the low-voltage battery are reduced, reducing the vehicle manufacturing cost and weight, improving the endurance potential, and directly calling the cell energy of the high-voltage power battery when the vehicle is in sleep mode, avoiding the self-discharge loss of the low-voltage battery.

[0039] Figure 4 Schematic diagram of the electric vehicle power supply method provided by the embodiment of this application Figure 2 , such as Figure 4 shown, this method further includes: S401: After the vehicle is powered on, receive a power supply switching instruction sent by the main controller.

[0040] The power-on of the whole vehicle (such as key start, remote wake-up) is the state transition of the vehicle from "sleep standby" to "operation ready". When in sleep, the low-voltage load only needs to maintain micro-power-consuming devices such as security (such as T-BOX, anti-theft controller) and communication. When in operation, the low-voltage load needs to support high-power devices (in the hundreds of watts level) such as air conditioners, entertainment systems, and electric power steering assist. In the traditional low-voltage power supply scheme (relying on an independent low-voltage battery), the DCDC starts after the whole vehicle is powered on, but the low-voltage battery and the DCDC are in parallel for a long time (without an active disconnection logic), and the voltage difference between the DCDC output and the low-voltage battery causes "circulating current" (for example, the DCDC outputs 14V and the low-voltage battery is 12V. When the two are in parallel, the battery is continuously charged, wasting energy). The low-voltage battery is independently managed by its own BMS and has no coordination with the vehicle VCU, and cannot accurately synchronize the timing of "DCDC start → battery stops power supply", which is likely to cause voltage fluctuations at the load end (for example, when the DCDC starts, the low-voltage battery is still discharging, causing a voltage spike). Then, the main controller can be used to dominate the transmission of the mode switching instruction of "sleep power supply (BMS cell direct supply) → operation power supply (DCDC main supply)", ensuring the safety of the timing and seamless power supply during the switching process, that is, first allowing the DCDC to stably output low-voltage electricity, and then cutting off the BMS cell direct supply, to avoid power-off of the low-voltage load or double-power supply parallel conflict.

[0041] Specifically, the vehicle controller first wakes up the step-down DCDC. After the step-down DCDC starts and stably outputs low-voltage electricity, it then sends a switching instruction to the BMS, ensuring that the step-down DCDC power supply is stable before cutting off the BMS cell direct supply, eliminating the circulating current and voltage fluctuations of the double-power supply parallel connection.

[0042] S402: Based on the power supply switching instruction, disconnect the conducting MOS tube in the AFE to stop power supply to the low-voltage electrical appliances.

[0043] In this step, when the vehicle is running, the power demand of the low-voltage load increases significantly (such as the air conditioner compressor, electric power steering assist, etc., with a power of up to hundreds of watts), while the "cell direct supply" implemented by the BMS through the MOS tube in the AFE can only meet the micro-power-consuming load in the sleep state (such as T-BOX, anti-theft controller, with a power < 10W). If the cell direct supply continues to supply the high-load in the running state, it will cause a single cell / few cells to continuously discharge at a large current, accelerating the aging of the cells, and the cell voltage will quickly drop under high load, triggering an under-voltage fault in the low-voltage system (such as ECU restart). Therefore, after the step-down DCDC takes over the power supply, the BMS cell direct supply circuit is cut off in time, allowing the energy of the high-voltage power battery to be transmitted through the conventional path of "DCDC step-down → low-voltage load", which not only meets the high-power demand in the running state but also protects the cell life. [[ID=ll]]

[0044] Specifically, after receiving the power supply switching instruction sent by the main controller, the BMS disconnects the conducting MOS tube to cut off the BMS cell direct supply circuit. \

[0045] The electric vehicle power supply method provided by this application, after the vehicle is powered on, receives a power supply switching instruction sent by the main controller. Based on the power supply switching instruction, disconnects the conducting MOS tube in the AFE and stops supplying power to the low-voltage electrical appliances. Through the above method, it solves the control pain points of non-coordination and easy conflict in the traditional low-voltage power supply mode switching, as well as the physical pain points that the direct supply of battery cells cannot meet the high load in the operating state and accelerates the aging of battery cells. It not only ensures the life of battery cells, but also reduces redundant hardware and control logic, and reduces the vehicle cost.

[0046] Figure 5 Schematic diagram of the electric vehicle power supply method provided by the embodiment of this application Figure 3 As Figure 5 shown, this method further includes: S501: After the BMS enables the battery cell inspection function, control the AFE to detect the voltage of the currently powered battery cell at a preset period.

[0047] In this step, during the vehicle sleep stage (only the AFE of the BMS supplies power to the low-voltage load), continuously monitor the voltage state of the currently powered battery cell, which can pre-warn the under-voltage risk and provide data basis for subsequent battery cell switching. The traditional low-voltage power supply relies on independent lead-acid / lithium batteries, and its voltage monitoring is independently completed by the BMS of the battery itself. It is necessary to additionally arrange voltage sampling harnesses, protection boards, and communication modules for the low-voltage battery, increasing the vehicle cost and weight. The BMS of the low-voltage battery communicates with the vehicle controller through CAN (message period ≥ 20ms), and the under-voltage warning delay is high, which is likely to cause deep discharge of the battery cell. Therefore, after the BMS enables the battery cell inspection function, the AFE can be controlled to detect the voltage of the currently powered battery cell at a preset period.

[0048] S502: When the voltage of the currently powered battery cell is lower than the preset discharge cut-off threshold, the AFE triggers a hardware interrupt to wake up the BMS.

[0049] In this step, when the voltage of the currently powered battery cell drops to the discharge cut-off threshold (such as 2.8V for ternary lithium and 2.5V for lithium iron phosphate), quickly wake up the BMS to perform battery cell switching to avoid deep discharge of the battery cell.

[0050] S503: After the BMS collects the voltages of all high-voltage power batteries, screen the battery cell group with the highest voltage priority as the next group of powered battery cells.

[0051] In this step, in order to ensure normal power supply, select a battery cell group with sufficient voltage and balanced life among multiple battery cells as the next power supply source, avoid over-discharge of a single battery cell, and extend the life of the entire high-voltage power battery pack.

[0052] Exemplarily, an intelligent priority algorithm can be adopted. First priority: the voltage is within ±5% of the average voltage of the battery cell group (to avoid selecting fully charged / discharged battery cells and reduce the equalization pressure); Second priority: the least cumulative discharge times (equalize the cycle times of each battery cell to make the difference in discharge times of the whole pack of battery cells less than 10%).

[0053] S504: The BMS controls the AFE to disconnect the current power supply circuit and turn on the MOS tube corresponding to the next group of power supply battery cells, so that the next group of power supply battery cells supply power to the low-voltage electrical appliances.

[0054] In this step, while disconnecting the current power supply battery cells, quickly turn on the MOS tubes of the next group of battery cells to achieve "seamless power switching" and ensure the continuous operation of low-voltage loads (such as T-BOX and anti-theft controller).

[0055] The electric vehicle power supply method provided by this application, after the BMS enables the battery cell inspection function, controls the AFE to detect the voltage of the current power supply battery cells at a preset period. When the voltage of the current power supply battery cells is lower than the preset discharge cut-off threshold, the AFE triggers a hardware interrupt to wake up the BMS. After the BMS collects the voltages of all high-voltage power batteries, it screens out the battery cell group with the highest voltage priority as the next group of power supply battery cells. The BMS controls the AFE to disconnect the current power supply circuit and turn on the MOS tube corresponding to the next group of power supply battery cells, so that the next group of power supply battery cells supply power to the low-voltage electrical appliances. Through the above method, deep discharge of the battery cells is avoided, the battery cell life is maximized, the low-voltage power supply continuity is ensured, the low-voltage battery and the attached BMS are cancelled, which not only reduces the weight but also reduces the cost, and completely eliminates the vicious cycle of "under-voltage power-off → load restart → increased power consumption" of the traditional low-voltage battery, and the reliability of the vehicle electrical system is improved.

[0056] Figure 6 It is a schematic structural diagram of the BMS provided by the embodiment of this application, as Figure 6 shown, the BMS 600 includes: a storage unit 602 and a processing unit 601; The storage unit 602 stores computer execution instructions; The processing unit 601 executes the computer execution instructions stored in the storage unit 602, so that the processing unit 601 executes the above method.

[0057] Optionally, the BMS further includes a communication component 603. Among them, the processing unit 601, the storage unit 602 and the communication component 603 are connected through a bus 604.

[0058] In the above embodiments, it should be understood that the processor may be a central processing unit (CPU for short), or other general-purpose processors, digital signal processors (DSP for short), application specific integrated circuits (ASIC for short), etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The steps of the method disclosed in combination with the invention can be directly implemented by the execution of the hardware processor, or by the combination of hardware and software modules in the processor.

[0059] The memory may include a high-speed random access memory (RAM), and may also include non-volatile memory (NVM), such as at least one disk memory.

[0060] The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, the bus in the drawings of this application is not limited to only one bus or one type of bus.

[0061] This application also provides a computer program product, including a computer program which, when executed by a processor, implements the above method.

[0062] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above method.

[0063] The above-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, a magnetic disk or an optical disk. The readable storage medium can be any available medium accessible by a general-purpose or special-purpose computer.

[0064] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an Application Specific Integrated Circuits (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in a device.

[0065] The division of units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Additionally, the couplings or direct couplings or communication connections shown or discussed among each other can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0066] The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0067] In addition, in each embodiment of the present invention, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0068] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or part of this technical solution can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in each embodiment of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks or optical discs that can store program codes.

[0069] Those of ordinary skill in the art will understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments; and the aforementioned storage medium includes: various media such as ROM, RAM, magnetic disks, or optical discs that can store program codes.

[0070] Finally, it should be noted that those skilled in the art will readily think of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention, which follow the general principles of the present invention and include common general knowledge or conventional technical means in the technical field not disclosed in the present invention. It is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. An electric vehicle power supply system, characterized in that, Including: A high-voltage power battery, a step-down DC-DC converter DCDC, a battery management controller BMS, a vehicle controller, and low-voltage electrical appliances; The high-voltage power battery is connected to the input end of the step-down DCDC, the high-voltage power battery is connected to the BMS, the low-voltage electrical appliances are connected in parallel to the output end of the step-down DCDC and the output end of the BMS, and the vehicle controller is communicatively connected to the step-down DCDC and the BMS; The BMS internally integrates a battery management chip AFE, and the AFE internally integrates multiple groups of metal-oxide-semiconductor field effect transistors MOS; The high-voltage power battery integrates multiple series-connected battery cells; Each battery cell is connected to a group of MOS transistors; The BMS is used to control at least two groups of MOS transistors inside the AFE to conduct, so that at least one battery cell in the high-voltage power battery supplies power to the low-voltage electrical appliances.

2. The system according to claim 1, wherein Each group of MOS transistors includes a high-side MOS transistor and a low-side MOS transistor; The first end of the high-side MOS transistor is connected to the positive electrode of the corresponding battery cell, and the second end of the high-side MOS transistor is connected to the positive electrode of the low-voltage electrical appliance; The first end of the low-side MOS transistor is connected to the negative electrode of the corresponding battery cell, and the second end of the low-side MOS transistor is connected to the negative electrode of the low-voltage electrical appliance.

3. The system according to claim 1, wherein The BMS is also used to automatically switch to a backup battery cell group and report a fault code to the vehicle controller when the AFE detects overcurrent or short circuit of the MOS transistor.

4. The system according to claim 1, characterized in that, The step-down DCDC is used to step down the high voltage output by the high-voltage power battery and supply power to the low-voltage electrical appliances.

5. A method for supplying power to an electric vehicle, characterized in that, A battery management controller BMS applied to the electric vehicle power supply system according to any one of claims 1 to 4, the method includes: After the vehicle is powered off, receive a low-voltage power-on request sent by the main controller; Based on the low-voltage power-on request, the BMS controls at least two groups of metal-oxide-semiconductor field effect transistors MOS in the internal battery management chip AFE to conduct, so that at least one battery cell in the high-voltage power battery supplies power to the low-voltage electrical appliances.

6. The method according to claim 5, wherein The method further includes: After the BMS wakes up and starts the battery cell inspection function, send a sleep feedback message to the main controller, so that the main controller controls the step-down DC-DC converter DCDC to stop supplying power.

7. The method according to claim 5, wherein The method further includes: After the vehicle is powered on, receive a power supply switching instruction sent by the main controller; Based on the power supply switching instruction, disconnect the conducting MOS transistors in the AFE and stop supplying power to the low-voltage electrical appliances.

8. The method according to claim 6, characterized in that, The method further includes: After the BMS enables the battery cell inspection function, control the AFE to detect the voltage of the currently powered battery cell at a preset period; When the voltage of the currently powered battery cell is lower than a preset discharge cut-off threshold, the AFE triggers a hardware interrupt to wake up the BMS; After the BMS collects the voltages of all the high-voltage power batteries, screen the battery cell group with the highest voltage priority as the next group of powered battery cells; The BMS controls the AFE to disconnect the current power supply circuit and conduct the MOS transistors corresponding to the next group of powered battery cells, so that the next group of powered battery cells supply power to the low-voltage electrical appliances.

9. A BMS, characterized in that, Comprising: A storage unit and a processing unit; The storage unit stores computer-executable instructions; The processing unit executes the computer-executable instructions stored in the storage unit, such that the processing unit executes the method according to any one of claims 5-8.

10. A computer-readable storage medium, characterized in that, Computer-executable instructions are stored in the computer-readable storage medium, and when the computer-executable instructions are executed by a processor, they are used to implement the method according to any one of claims 5-8.

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