48v battery system emergency cold start method

Abstract

The present application relates to the field of lithium ion battery, disclose a kind of 48V battery system emergency cold start method, including 12V battery starting system, 48V battery system, DC / DC converter, VCU / EMS control system, BSG motor;The low-voltage system includes 12V battery, starter, display instrument and the like;The 48V battery system includes 48V battery, 48V battery management system and accessory structure;The strategy of the present application does not need to increase other components in the original battery starting system, does not need to design separately, solve the 48V micro-hybrid vehicle in 12V battery can guarantee for 48V battery management system and DCDC control chip provides energy, but cannot start the whole vehicle state under the predicament.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion batteries, and in particular to an emergency cold start method for a 48V battery system. Background Technology

[0002] With increasingly stringent fuel consumption and emission regulations both domestically and internationally, major OEMs have begun to focus on developing powertrain systems with ultra-high fuel economy, leading to the emergence of the 48V mild hybrid system. The 48V mild hybrid system utilizes a 48V battery system to achieve automatic start-stop, engine-off coasting, coasting and braking energy recovery, acceleration assist, and electric cruise control. The 12V battery provides energy for vehicle starting, 12V vehicle load, and 48V battery management. The 48V battery, in turn, provides energy to the 12V system via a DC / DC converter.

[0003] In certain situations, such as prolonged parking or recreational use while parked, the 12V battery may become depleted due to power consumption. Since the 48V battery management system is not operational, it cannot supply power to the 12V battery via the DC / DC converter. The most common solution is to jump-start the 12V battery or use other external charging methods. Once the 12V battery has sufficient power to start the vehicle, the vehicle's power supply system can function normally. However, this method is time-consuming and laborious, significantly impacting the driving experience of 48V mild hybrid vehicles. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the aforementioned technologies by providing a strategy that enables the vehicle to start normally when the 12V battery is depleted and cannot be started, but can provide power to the 48V battery management system and DC / DC control communication chip.

[0005] An emergency cold start method for a 48V battery system, in the case where the 12V battery is depleted but the 48V battery management system (BMS) is operational, involves the following steps:

[0006] A key / button start, the VCU / EMS control system receives the start signal, the 48V battery management system BMS is powered on, and the cold start counting system starts;

[0007] B determines whether the number of emergency cold starts for the 48V battery has reached the maximum emergency start limit m times. If it is determined that the maximum number of emergency cold starts m times has been reached, the instrument panel will prompt "The number of emergency cold starts has reached the limit, and the start has failed," and the process will be terminated. If the limit has not been reached, the current charge level of the 48V battery will be judged. If the charge level of the 48V battery does not meet the preset state of charge value requirement, the emergency cold start process will not be initiated, and the instrument panel will prompt "The 48V battery charge is insufficient, and the emergency cold start cannot be initiated." If the charge level of the 48V battery meets the preset state of charge value requirement, the 48V battery management system (BMS) will send information to the instrument panel, and the instrument panel will prompt "The 12V battery is low on charge, and the emergency cold start will be initiated." The 48V battery relay will be closed through the VCU / EMS control system, and the 48V battery will replenish the 12V battery through the DC / DC converter. The replenishment time is T. After the replenishment time is reached, the 48V battery management system (BMS) will send information to the instrument panel, and the instrument panel will prompt "Charging complete, start the vehicle again."

[0008] When starting via C key / button, the 12V battery and DC / DC converter discharge together to provide cold start energy for the entire vehicle upon restarting.

[0009] D determines whether the vehicle has started successfully (if the vehicle starter / engine is running normally, it is considered a successful start): If the start is successful, the instrument panel will display "Emergency cold start successful", and the cold start counter system will be reset to zero; if the cold start fails, the cold start counter system will increment by 1.

[0010] If steps B, C, and D are repeated m times consecutively, the emergency cold start will fail, and a notification will be sent indicating that the maximum number of emergency cold starts has been reached, resulting in a failed start and aborting the process.

[0011] The value of m is 3.

[0012] In step B, the instrument prompts "12V battery low, start emergency cold start", and after a 2-second delay, the instrument prompts "Emergency cold start activated".

[0013] An emergency cold start system for a 48V battery system, comprising:

[0014] Cold start counting system to count the number of emergency cold starts of a 48V battery;

[0015] The comparison module checks whether the number of emergency cold starts of the 48V battery counted by the cold start counting system has reached the emergency start limit m times. If the limit m times has been reached, the termination process is executed. If the limit has not been reached, the current power level of the 48V battery is assessed. If the 48V battery power level does not meet the preset state of charge (SCC) requirement, the emergency cold start process is not initiated. If the 48V battery power level meets the preset SCC requirement, the 48V battery management system (BMS) sends information to the instrument, which prompts "12V battery low, initiate emergency cold start" and controls the 48V battery relay to close via the VCU / EMS control system. The 48V battery then replenishes the 12V battery through the DC / DC converter for a replenishment time of T.

[0016] The start-up judgment module determines whether the vehicle has started successfully. If it starts successfully, the cold start counting system is reset to zero. If the cold start fails, the cold start counting system is incremented by 1. When the number of emergency cold starts for the 48V battery reaches m times, the emergency cold start fails. The system will remind you that the number of emergency cold starts has reached the limit and the start-up process will be terminated.

[0017] The display module shows the results of the comparison module and the start judgment module on the instrument.

[0018] A control system for the above-mentioned emergency cold start method of a 48V battery system includes a 12V battery starting system, a 48V battery system, a DC / DC converter, and a VCU / EMS control system. The 12V battery starting system includes a 12V battery, a starter motor, and an instrument panel. The 48V battery system includes a 48V battery, a 48V battery management system, and a BSG motor. The negative terminals of the 12V and 48V batteries are grounded, and the positive terminal of the 48V battery is connected to the high-voltage input terminal of the BSG motor and the DC / DC converter in the 48V battery system. The 48V battery management system is powered by the 12V battery. The 48V battery management system, the BSG motor, and the DC / DC converter communicate with the VCU / EMS control system via a CAN bus. The 48V battery system emergency cold start system is located within the VCU / EMS control system.

[0019] The 12V battery starting system also includes a 12V electrical device and a low-voltage load. One end of the 12V electrical device and the low-voltage load are connected to the negative terminal of the 12V battery, and the other end of the 12V electrical device and the low-voltage load are connected to the positive terminal of the 12V battery.

[0020] The 48V battery system also includes a 48V high-voltage load, one end of which is connected to the negative terminal of the power battery and the other end of which is connected to the positive terminal of the power battery management system.

[0021] To achieve the above objectives, the 48V battery emergency cold start strategy designed in this invention detects and determines the 12V battery status through the VCU / EMS system. If the current battery system can meet the operating requirements of the 48V battery system and DC / DC converter, a 48V battery relay closing command can be used to convert the 48V voltage to 12V, providing energy to the 12V battery and enabling the normal start of the 48V vehicle system. The vehicle components involved in this strategy include the 12V battery starting system, the 48V battery system, the DC / DC converter, the BSG motor, and the VCU / EMS controller. The system includes, but is not limited to, a 12V lead-acid battery, a starter motor, and display instruments; the 48V battery system includes, but is not limited to, a 48V lithium-ion battery and a 48V battery management system; the negative terminals of the 12V and 48V batteries are grounded, and the positive terminal of the 48V battery is connected to the high-voltage input terminal of the BSG and DC / DC converter in the 48V system; the 48V battery management system is powered by the 12V battery; the 48V battery management system, the BSG motor, and the DC / DC converter communicate with the VCU / EMS management system via a CAN bus. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart of the emergency cold start method of the present invention;

[0024] Figure 2 This is a block diagram of the control system used for emergency cold start of a 48V battery system. Detailed Implementation

[0025] The technical solution of the present invention will now be clearly and completely described with reference to specific embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] The specific start-up process of the hybrid electric vehicle start-up system of the present invention is as follows: When the vehicle receives a start signal, the cold start counting system of the 48V battery management system (hereinafter referred to as BMS) is activated to determine whether the number of emergency cold starts of 48V has reached the start limit. If the emergency cold start limit is reached, the system will remind that the number of emergency cold starts has reached the limit, the start-up has failed, and the process will be terminated. If the limit has not been reached, the system will determine the current 48V power.

[0027] If the 48V battery has sufficient charge for a cold start, the emergency cold start procedure will be initiated. The 48V relay will close via the VCU / EMS, and the 48V battery will replenish the 12V battery through the DC / DC converter. After a specified time, the emergency cold start will be complete, and the vehicle can be started again. Upon restarting, the 12V battery and the DC / DC converter will discharge together to provide cold start energy for the entire vehicle.

[0028] If the cold start is successful, the process ends. If the cold start fails, the counter is incremented by 1, and the emergency cold start count is checked again. If the number of emergency cold starts fails 3 times within a counting cycle, a reminder is issued that the maximum number of emergency cold starts has been reached, the start fails, and the process is terminated.

[0029] Figure 2 This invention relates to a control system for emergency cold start of a 48V battery system, comprising a 12V battery starting system, a 48V battery system, a DC / DC converter 2, and a VCU / EMS control system 7. The 12V battery starting system includes a 12V battery 8, a starter motor 3, and an instrument panel 4. The 48V battery system includes a 48V battery 5, a 48V battery management system 6, and a BSG motor 1. The negative terminals of the 12V battery 8 and the 48V battery 5 are grounded, and the positive terminal of the 48V battery 5 is connected to the high-voltage input terminals of the BSG motor 1 and the DC / DC converter 2 in the 48V battery system. The 48V battery management system 6 is powered by the 12V battery 8. The 48V battery management system 6, the BSG motor 1, and the DC / DC converter 2 communicate with the VCU / EMS control system 7 via a CAN bus. The emergency cold start system is integrated within the VCU / EMS control system. The 12V battery starting system also includes a 12V electrical device and a low-voltage load. One end of each of the 12V electrical device and the low-voltage load is connected to the negative terminal of the 12V battery, and the other end is connected to the positive terminal of the 12V battery. The 48V battery system also includes a 48V high-voltage load. One end of the 48V high-voltage load is connected to the negative terminal of the power battery, and the other end is connected to the positive terminal of the power battery management system.

Claims

1. A method for emergency cold start of a 48V battery system, characterized in that: If the 12V battery is depleted but the 48V battery management system (BMS) is still operational, follow these steps: A key / button start, the VCU / EMS control system receives the start signal, the 48V battery management system BMS is powered on, and the cold start counting system starts; B determines whether the number of emergency cold starts for the 48V battery has reached the emergency start limit m times. If it is determined that the emergency cold start limit m times has been reached, the instrument will remind "the number of emergency cold starts has reached the limit, the start has failed" and abort the process. If the upper limit is not reached, the current charge level of the 48V battery is assessed. If the 48V battery charge does not meet the preset state of charge (SCC) requirement, the emergency cold start procedure is not initiated, and the instrument panel displays the message "48V battery charge is insufficient, emergency cold start cannot be initiated." If the 48V battery charge meets the preset SCC requirement, the 48V battery management system (BMS) sends information to the instrument panel, which displays the message "12V battery is low, initiate emergency cold start." The BMS then controls the 48V battery relay to close via the VCU / EMS control system. The 48V battery then charges the 12V battery through the DC / DC converter for a charging time of T. After the charging time is reached, the 48V battery management system (BMS) sends information to the instrument panel, which displays the message "Charging complete, start the vehicle again." When starting via C key / button, the 12V battery and DC / DC converter discharge together to provide cold start energy for the entire vehicle upon restarting. D determines whether the vehicle has started successfully: If it starts successfully, the instrument panel will display "Emergency cold start successful" and the cold start counter system will be reset to zero; if the cold start fails, the cold start counter system will increment by 1. If steps B, C, and D are repeated m times consecutively, the emergency cold start will fail, and a notification will be sent indicating that the maximum number of emergency cold starts has been reached, resulting in a failed start and aborting the process.

2. The emergency cold start method for a 48V battery system according to claim 1, characterized in that: The value of m is 3.

3. The emergency cold start method for a 48V battery system according to claim 1, characterized in that: In step B, the instrument prompts "12V battery low, start emergency cold start", and after a 2-second delay, the instrument prompts "Emergency cold start activated".

4. An emergency cold start system for a 48V battery system, characterized in that: include: Cold start counting system to count the number of emergency cold starts of a 48V battery; The comparison module checks whether the number of emergency cold starts of the 48V battery counted by the cold start counting system has reached the emergency start limit m times; if the emergency cold start limit m times has been reached, the abort process is executed. If the upper limit is not reached, the current power level of the 48V battery is judged; if the power level of the 48V battery does not meet the preset state of charge value requirement, the emergency cold start process is not initiated. If the 48V battery power meets the preset state of charge value requirement, the 48V battery management system (BMS) will send information to the instrument. The instrument will remind "12V battery is low, start emergency cold start" and control the 48V battery relay to close through the VCU / EMS control system. The 48V battery will then replenish the 12V battery through the DC / DC converter. The replenishment time is T. The start-up judgment module determines whether the vehicle has started successfully. If it starts successfully, the cold start counting system is reset to zero. If the cold start fails, the cold start counting system is incremented by 1. When the number of emergency cold starts for the 48V battery reaches m times, the emergency cold start fails. The system will remind you that the number of emergency cold starts has reached the limit and the start-up process will be terminated. The display module shows the results of the comparison module and the start judgment module on the instrument.

5. A control system for the emergency cold start method of the 48V battery system as described in any one of claims 1-3, characterized in that: It includes a 12V battery starting system, a 48V battery system, a DC / DC converter, and a VCU / EMS control system; the 12V battery starting system includes a 12V battery, a starter motor, and an instrument panel. The 48V battery system includes a 48V battery, a 48V battery management system, and a BSG motor; The negative terminals of the 12V and 48V batteries are grounded, and the positive terminal of the 48V battery is connected to the high-voltage input terminal of the BSG motor and DC / DC converter in the 48V battery system. The 48V battery management system is powered by the 12V battery. The 48V battery management system, BSG motor, and DC / DC converter communicate with the VCU / EMS control system through the CAN bus. The 48V battery system emergency cold start system is set in the VCU / EMS control system.

6. The control system according to claim 5, characterized in that: The 12V battery starting system also includes a 12V electrical device and a low-voltage load. One end of the 12V electrical device and the low-voltage load are connected to the negative terminal of the 12V battery, and the other end of the 12V electrical device and the low-voltage load are connected to the positive terminal of the 12V battery.

7. The control system according to claim 5, characterized in that: The 48V battery system also includes a 48V high-voltage load, one end of which is connected to the negative terminal of the power battery and the other end of which is connected to the positive terminal of the power battery management system.

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