Processing method for communication loss of vehicle control unit and battery controller

Abstract

The invention relates to the technical field of electric vehicle control, in particular to a method for processing communication loss of a vehicle control unit and a battery controller, which comprises the following steps that: 1, when a VCU detects that a BMS key message or the whole BMS message is not received and lasts for a certain time, the VCU judges a communication loss fault with the BMS; 2, when diagnosing that the communication loss fault with the BMS is equal to 1, the VCU immediately locks some important parameters of the whole vehicle at the moment when the loss fault occurs; 3, the VCU judges according to the important parameters, so that the whole vehicle smoothly transits to a safe state; 5, the VCU sends information to the ICM instrument to be displayed, the display character can be a BMS communication loss super limphome mode, and meanwhile a whole vehicle system fault lamp and a battery system fault lamp are turned on to warn a driver; the problems that at the present stage, after a VCU cannot receive CAN information of a BMS controller, zero-power processing is adopted, the whole vehicle is in the state of being not powered on and not capable of being driven and can only wait for rescue, certain economic losses are caused to a driver, and the safety is affected are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle control, and in particular to a method for processing communication loss between a vehicle controller and a battery controller. Background Art

[0002] In new energy electric vehicles, the vehicle controller VCU and the battery controller BMS are two very important controllers, which exchange signals and process control strategies through the CAN bus.

[0003] Most manufacturers will report and determine the serious fault level of the vehicle and make corresponding fault handling after the VCU fails to receive the CAN information of the BMS controller, and most of them will handle the fault with zero power, stop the motor system from being enabled, and perform high voltage processing on the vehicle. The vehicle is in a state where it cannot be powered on and cannot be driven. In this case, the driver can only wait for rescue and tow the vehicle, which will cause certain economic losses to the driver. Sometimes there will be more expensive towing fees and the vehicle will directly break down and lose power, which will also affect certain safety. Summary of the invention

[0004] The present invention provides a processing method for the loss of communication between a vehicle controller and a battery controller, so as to solve the problem that at present, after the VCU fails to receive the CAN information of the BMS controller, most of the processing is zero power, the motor system is stopped, and the whole vehicle is subjected to high voltage processing. The whole vehicle is in a state where it cannot be powered on and cannot be driven, and can only wait for rescue and tow. This causes certain economic losses to the driver, and sometimes there are relatively expensive towing fees, and the vehicle directly breaks down and loses power, which also affects the safety to a certain extent.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a method for processing the communication loss between a vehicle controller and a battery controller, comprising a vehicle controller VCU, a battery controller BMS and an engine motor, wherein the engine motor is connected to a battery, and a DCDC, an OBC, an MCU and a PDU are connected in parallel between the engine motor and the battery. In the vehicle CAN network architecture, VCU, BMS, MCU, PDU, DCDC, OBC and ICM exchange information through a CAN bus, and the specific steps are as follows: Step S1, VCU detects that the BMS key message or the entire BMS message has not been received and continues for a certain period of time, then VCU determines that the communication with the BMS is lost; Step S2, when the diagnosis of the communication loss fault with the BMS = 1, the VCU will immediately lock some important vehicle parameters at the time of the loss fault; Step S3, the VCU will make a judgment based on important parameters to allow the vehicle to smoothly transition to a safe state; Step S4, the VCU sends information to the ICM instrument for display, and the displayed words may be "BMS communication lost super limphome mode", and the vehicle system fault light and the battery system fault light are lit at the same time to warn the driver; Step S5, VCU always wakes up BMS. BMS can detect various parameters of its own battery system, such as battery voltage, temperature, and whether there are serious faults. If BMS detects a serious fault during driving, it will cut off the contactor to protect its own battery system.

[0006] It is further defined that the important parameters in step S2 include the battery SOC, the highest / lowest cell voltage Vmax-Vmin of the power battery, the highest / lowest cell temperature Tmax-Tmin of the power battery, and whether the battery system has other serious faults.

[0007] Further defined, the determination according to the important parameters in step S3 refers to whether all the following conditions are met at the same time, if so, the VCU outputs "BMS communication lost super limphome mode = 1, if not, the VCU outputs "BMS communication lost super limphome mode = 0, the conditions are as follows: A. Battery soc ≥ 30% of the rated value; B. The maximum cell voltage of the power battery Vmax ≥ 3.4V; the minimum cell voltage Vmin ≥ 3.2V. The specific voltage data are set as calibration values, which need to be set and referenced according to the specific cell type and cell voltage performance curve; C. The maximum cell temperature of the power battery is: -10℃≤Tmax≤40℃, and the minimum cell temperature is: -10℃≤Tmin≤40℃. The specific temperature data are set as calibration values, which need to be set and referenced according to the specific cell type and cell temperature performance curve; D. There are no other serious faults in the battery system.

[0008] It is further defined that during step S2, the VCU will perform the maximum amplification power P of the battery under the current circumstances according to the battery sop table stored in the memory. The battery sop is a map table. The input is the maximum voltage value of the battery cell / the maximum temperature value of the battery cell, and the output is the maximum power value in the current state. If the current maximum power value P>10kw, then the VCU sets the current maximum available power of the internal BMS battery system to P(liphome)=10kw for the whole vehicle. P(liphome) is a calibration value. The specific setting needs to consider the following factors: 1.1. It can be determined according to the specific battery discharge power matrix map table and the vehicle's driving resistance parameters. 2.1. This value can ensure that the whole vehicle can drive at the standard value of 10km / h. 3.1. It can ensure that the whole vehicle can pass through ordinary speed bumps and lanes with a certain slope. 4.1. Most of the power values ​​in the entire battery discharge power map data are greater than this value, mainly to ensure the discharge safety of the battery.

[0009] Further limitation, VCU will transition from the discharge power value at step S2 to the current P (liphome) value with a certain slope gradient to prevent the vehicle from losing power too quickly, causing comfort problems and bad feelings of power loss too quickly; the slope gradient can be calibrated to 1kw / s, at this time the power output formula of the vehicle is motor power = P (liphome) - P (DCDC) - P air conditioning, at the same time, VCU will receive the bus current of DCDC and the high-voltage bus current of the air conditioning system in real time, and perform ampere-hour integration AH = bus current of DCDC * t + high-voltage bus current of the air conditioning system * t, time t represents the VCU program operation cycle, which is 10ms, VCU uses the consumed ampere-hour data to estimate the subsequent soc, if SOC = 0, VCU controls the vehicle to power off at high voltage, and cannot continue to drive; ampere-hour integration AH = SOC value that can be reported by the battery when communication is lost * stable ampere-hour capacity of the battery system; It is further defined that the serious faults described in step S5 will be carefully constrained and considered during the development process; only when a battery over-discharge fault, a battery over-temperature fault, or a battery thermal runaway fault occurs, the BMS will activate the secondary redundant self-protection processing, allowing the BMS to automatically cut off the contactor and power off the high voltage.

[0010] The beneficial effects of adopting the above technical solution are: Through the above strategy, when the communication between VCU and BMS is lost, the vehicle can still continue to drive, ensuring that the driver can go to the maintenance point for timely maintenance and avoid economic losses such as towing fees; at the same time, the strategy also protects the battery to the greatest extent, and gives the vehicle sufficient maximum power output to ensure a certain vehicle power performance; at critical moments, it also gives the BMS battery system the greatest safety protection. Under special circumstances, the battery system's secondary self-protection measures can be activated to protect the safety of the battery and the entire vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a high voltage system architecture diagram of the present invention; Figure 2 This is a network architecture information interaction diagram of the present invention; Figure 3 It is a logical relationship schematic diagram of the present invention. DETAILED DESCRIPTION

[0012] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0013] The present invention is a processing method for the loss of communication between a vehicle controller and a battery controller, which solves the problem that at present, after the VCU fails to receive the CAN information of the BMS controller, most of the processing is zero power, the motor system is stopped, the whole vehicle is subjected to high voltage processing, the whole vehicle is in a state where it cannot be powered on and cannot be driven, and can only wait for rescue and tow the vehicle, which causes certain economic losses to the driver, and sometimes there are relatively expensive towing fees, and the vehicle directly breaks down and loses power, which also affects certain safety issues. Specifically, Figure 1-Figure 3 As shown, a method for processing the loss of communication between a vehicle controller and a battery controller is characterized in that: it includes a vehicle controller VCU, a battery controller BMS and an engine motor, the engine motor is connected to a battery, and a DCDC, an OBC, an MCU and a PDU are connected in parallel between the engine motor and the battery. In the high-voltage architecture, the pre-charge contactor, the main positive contactor, and the main and auxiliary contactors are all specifically controlled in two directions by the PDU high-voltage distribution unit and the BMS, that is, as long as one party drives the contactor to close, the contactor will be closed, and only when both parties are in the open state, the contactor will be in the open state; the PDU's control closing and opening instructions for the contactor are output by the VCU. In the vehicle CAN network architecture, VCU, BMS, MCU, PDU, DCDC, OBC, and ICM exchange information through the CAN bus. The specific steps are as follows: Step S1: If the VCU detects that the BMS key message or the entire BMS message has not been received for a certain period of time (the calibration value of the duration is generally 3-5 times the message cycle), the VCU determines that the communication with the BMS is lost; Step S2, when the diagnosis fault of communication loss with BMS = 1, the VCU will immediately lock some important parameters of the vehicle at the time of the loss fault, including the battery SOC, the highest / lowest single cell voltage Vmax-Vmin of the power battery, the highest / lowest single cell temperature Tmax-Tmin of the power battery, and whether the battery system has other serious fault parameters, such as insulation, high-voltage interlock, etc. At the same time, the VCU will perform the maximum amplification power P of the battery in the current situation according to the battery sop table stored in the memory. The battery sop is a map table. The input is the maximum value of the battery cell voltage / the maximum value of the battery cell temperature, and the output is the maximum power value in the current state. If the current power value P>10kw, then the VCU sets the current maximum available power of the internal BMS battery system to P(liphome)=10kw , for the whole vehicle, P (liphome) is a calibration value, and the specific setting needs to consider the following factors: 1.1, it can be determined according to the specific battery discharge power matrix map table and the vehicle's driving resistance parameters, 2.1, this value can ensure that the whole vehicle can drive at the standard value of 10km / h, 3.1, it can ensure that the whole vehicle can pass through ordinary speed bumps and lanes with a certain slope, 4.1, most of the power values ​​in the entire battery discharge power map data are greater than this value, mainly to ensure the discharge safety of the battery, VCU will transition from the discharge power value at the moment of step S2 to the current P (liphome) value with a certain slope gradient to prevent the whole vehicle from losing power too quickly, causing comfort problems and unpleasant feelings of losing power too quickly; the slope gradient can be calibrated to 1kw / s, at this time the power output formula of the whole vehicle is motor power = P(liphome)-P(DCDC)-P air conditioning. At the same time, VCU will receive the bus current of DCDC and the high-voltage bus current of the air conditioning system in real time, and perform ampere-hour integration AH=DCDC bus current*t+high-voltage bus current of the air conditioning system*t. Time t represents the VCU program operation cycle, which is 10ms. VCU uses the consumed ampere-hour data to estimate the subsequent SOC. If SOC=0, VCU controls the vehicle to power off at high voltage and cannot continue to drive; ampere-hour integration AH=SOC value reported by the battery when communication is lost*stable ampere-hour capacity of the battery system; Step S3, VCU will make a judgment based on important parameters to allow the vehicle to smoothly transition to a safe state. When the following conditions are met at the same time, VCU outputs "BMS communication loss super limphome mode = 1", otherwise VCU outputs "BMS communication loss super limphome mode = 0", the conditions are as follows: A. Battery soc ≥ 30% of the rated value; B. The maximum cell voltage of the power battery Vmax ≥ 3.4V; the minimum cell voltage Vmin ≥ 3.2V. The specific voltage data are set as calibration values, which need to be set and referenced according to the specific cell type and cell voltage performance curve; C. The maximum cell temperature of the power battery is: -10℃≤Tmax≤40℃, and the minimum cell temperature is: -10℃≤Tmin≤40℃. The specific temperature data are set as calibration values, which need to be set and referenced according to the specific cell type and cell temperature performance curve; D. There are no other serious faults in the battery system; Step S4, when the VCU outputs "BMS communication lost super limphome mode = 1, the VCU sends information to the ICM instrument for display, and the displayed words may be "BMS communication lost super limphome mode", and the vehicle system fault light and the battery system fault light are lit to warn the driver; In step S5, the VCU always wakes up the BMS. The BMS can detect various parameters of its own battery system, such as battery voltage, temperature, and whether there are serious faults. If the BMS detects a serious fault during driving, it will cut off the contactor to protect its own battery system. The detected serious faults will be carefully constrained and considered during the development process; only when a battery over-discharge fault, battery over-temperature fault, or battery thermal runaway fault occurs, the BMS will start the secondary redundant self-protection processing, allowing the BMS to cut off the contactor by itself and power off the high voltage.

[0014] In order to let the vehicle controller get the information that the battery BMS starts the secondary protection, the BMS will transmit a hard-wired high-level signal to the VCU while outputting the contactor cut-off signal. Normally, the signal is a low-level signal. After the VCU receives the high-level secondary protection signal, it will send a contactor disconnection command to the PDU at the same time. The PDU will also disconnect the contactor. At this time, the high-voltage contactor of the whole vehicle will be completely disconnected normally, and the whole vehicle will be in a high-voltage cut-off state to protect the battery from dangerous faults.

[0015] Through the above strategy, when the communication between VCU and BMS is lost, the vehicle can still continue to drive, ensuring that the driver can go to the maintenance point for timely maintenance and avoid economic losses such as towing fees; at the same time, the strategy also protects the battery to the greatest extent, and gives the vehicle sufficient maximum power output to ensure a certain vehicle power performance; at critical moments, it also gives the BMS battery system the greatest safety protection. Under special circumstances, the battery system's secondary self-protection measures can be activated to protect the safety of the battery and the entire vehicle.

[0016] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above-mentioned concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for processing the loss of communication between a vehicle controller and a battery controller, characterized in that: It includes a vehicle controller VCU, a battery controller BMS and an engine motor. The engine motor is connected to the battery. DCDC, OBC, MCU and PDU are connected in parallel between the engine motor and the battery. In the vehicle CAN network architecture, VCU, BMS, MCU, PDU, DCDC, OBC and ICM exchange information through the CAN bus. The specific steps are as follows: Step S1, VCU detects that the BMS key message or the entire BMS message has not been received and continues for a certain period of time, then VCU determines that the communication with the BMS is lost; Step S2, when the diagnosis of the communication loss fault with the BMS = 1, the VCU will immediately lock some important vehicle parameters at the time of the loss fault; Step S3, the VCU will make a judgment based on important parameters to allow the vehicle to smoothly transition to a safe state; Step S4, the VCU sends information to the ICM instrument for display, and the displayed words may be "BMS communication lost super limphome mode", and the vehicle system fault light and the battery system fault light are lit at the same time to warn the driver; Step S5, VCU always wakes up BMS. BMS can detect various parameters of its own battery system, such as battery voltage, temperature, and whether there are serious faults. If BMS detects a serious fault during driving, it will cut off the contactor to protect its own battery system.

2. A method for processing loss of communication between a vehicle controller and a battery controller according to claim 1, characterized in that: The important parameters in step S2 include the battery SOC, the highest / lowest cell voltage Vmax-Vmin of the power battery, the highest / lowest cell temperature Tmax-Tmin of the power battery, and whether the battery system has other serious faults.

3. A method for processing loss of communication between a vehicle controller and a battery controller according to claim 1, Features: The determination according to the important parameters in step S3 refers to whether all the following conditions are met at the same time. If so, the VCU outputs "BMS communication lost super limphome mode = 1, otherwise the VCU outputs "BMS communication lost super limphome mode = 0", and the conditions are as follows: A. Battery soc ≥ 30% of the rated value; B. The maximum cell voltage of the power battery Vmax ≥ 3.4V; the minimum cell voltage Vmin ≥ 3.2V. The specific voltage data are set as calibration values, which need to be set and referenced according to the specific cell type and cell voltage performance curve; C. The maximum cell temperature of the power battery is: -10℃≤Tmax≤40℃, and the minimum cell temperature is: -10℃≤Tmin≤40℃. The specific temperature data are set as calibration values, which need to be set and referenced according to the specific cell type and cell temperature performance curve; D. There are no other serious faults in the battery system.

4. A method for processing loss of communication between a vehicle controller and a battery controller according to claim 1, characterized in that: During step S2, the VCU will use the battery sop table stored in the memory to calculate the maximum amplified power P of the battery in the current situation. The battery sop is a map table. The input is the maximum voltage value of the battery cell / the maximum temperature value of the battery cell. The output is the maximum power value in the current state. If the current maximum power value P>10kw, then the VCU sets the current maximum available power of the internal BMS battery system to P(liphome)=10kw for the whole vehicle. P(liphome) is a calibrated value. The specific setting needs to consider the following factors: 1.

1. It can be determined based on the specific battery discharge power matrix map table and the vehicle's driving resistance parameters. 2.

1. This value can ensure that the vehicle can travel at the standard value of 10km / h. 3.

1. It can ensure that the vehicle can pass through ordinary speed bumps and lanes with a certain slope. 4.

1. Most of the power values ​​in the entire battery discharge power map data are greater than this value, which mainly ensures the discharge safety of the battery.

5. A method for processing loss of communication between a vehicle controller and a battery controller according to claim 4, Features: The VCU will transition from the discharge power value at step S2 to the current P (liphome) value at a certain slope gradient to prevent the vehicle from losing power too quickly, causing comfort problems and unpleasant feelings due to too fast power loss; the slope gradient can be calibrated to 1kw / s, at which time the power output formula of the vehicle is motor power = P (liphome) - P (DCDC) - P air conditioning. At the same time, the VCU will receive the bus current of the DCDC and the high-voltage bus current of the air conditioning system in real time, and perform ampere-hour integration AH = bus current of the DCDC * t + high-voltage bus current of the air conditioning system * t. Time t represents the VCU program operation cycle, which is 10ms. The VCU uses the consumed ampere-hour data to estimate the subsequent soc. If SOC = 0, the VCU controls the vehicle to power off at high voltage and cannot continue to drive. Ah integral AH = SOC value reported by the battery when communication is lost * stable Ah capacity of the battery system.

6. A method for processing loss of communication between a vehicle controller and a battery controller according to claim 1, characterized in that: The serious faults in step S5 will be carefully constrained and considered during the development process; Only when a battery over-discharge fault, battery over-temperature fault, or battery thermal runaway fault occurs, the BMS will activate the secondary redundant self-protection processing, allowing the BMS to automatically cut off the contactor and power off the high voltage.

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