CN114475349A

CN114475349A - Electric vehicle battery output power control method and system, storage medium and vehicle

Info

Publication number: CN114475349A
Application number: CN202011150485.4A
Authority: CN
Inventors: 高斌; 吴红; 李德伟
Original assignee: Beiqi Foton Motor Co Ltd
Current assignee: Beiqi Foton Motor Co Ltd
Priority date: 2020-10-23
Filing date: 2020-10-23
Publication date: 2022-05-13

Abstract

The application provides a method and a system for controlling battery output power of an electric vehicle, a storage medium and a vehicle. The method comprises the following steps: the battery management system responds to the switching of a vehicle to a limit output mode, and determines a limit output power parameter of a battery according to the current state parameter of the battery; the battery management system sends a limit output power parameter to the vehicle controller; and the vehicle control unit controls the first output power of the battery according to the limit output power parameter. And configuring a limit output mode, when the vehicle is switched to the limit output mode, determining a limit output power parameter of the battery by the battery management system according to the current state parameter of the battery, and sending the limit output power parameter to the vehicle control unit, and controlling the output power of the battery by the vehicle control unit according to the limit output power parameter. Thereby enabling the energy type battery to realize energy supply by discharging to the outside at the limit output power parameter.

Description

Electric vehicle battery output power control method and system, storage medium and vehicle

Technical Field

The application relates to the technical field of battery energy storage, in particular to a method and a system for controlling battery output power of an electric vehicle, a storage medium and a vehicle.

Background

More and more vehicles are driven by electric energy, and the vehicles mainly adopt power batteries to store the electric energy. Power batteries are generally classified into energy type batteries and power type batteries. The space for arranging the power battery in the vehicle is limited, and in order to enable the power battery arranged in the limited space to store as much electric energy as possible, the energy type lithium ion battery is mostly adopted by the electric vehicle, and the battery has the main characteristics of high energy density but low power performance. In the related art, the control method for the output power of the energy type battery has been able to satisfy the traveling power demand of a general vehicle, but has not been able to satisfy the high acceleration power demand of a medium-high end passenger vehicle (e.g., a sports car) or the high load operation power demand of a special vehicle (e.g., a forklift).

Disclosure of Invention

The application provides a method and a system for controlling the output power of an electric vehicle battery, a storage medium and a vehicle, which are used for solving the problem that the control method of the output power of an energy type battery in the related technology cannot meet the high acceleration power requirement of a medium-high-end passenger vehicle or the high load operation power requirement of a special vehicle.

A first aspect of an embodiment of the present application provides a method for controlling output power of a battery of an electric vehicle, where the method includes:

the battery management system responds to the switching of a vehicle to a limit output mode, and determines a limit output power parameter of a battery according to the current state parameter of the battery;

the battery management system sends a limit output power parameter to the whole vehicle controller;

and the vehicle control unit controls the first output power of the battery according to the limit output power parameter.

Optionally, the battery management system, in response to the vehicle switching to the limit output mode, determines the limit output power parameter of the battery according to the current state parameter of the battery, and includes:

the battery management system detects whether the state of charge of the battery is greater than a first threshold value in response to a vehicle switching to a limit output mode;

and the battery management system responds to the detection result that the state of charge of the battery is larger than a first threshold value, and determines the limit output power parameter of the battery according to the current state parameter of the battery.

the battery management system responds to the vehicle switching to the limit output mode, and detects whether the state of charge of the battery is larger than a first threshold value and whether the working environment temperature of the battery is within a first temperature interval;

and the battery management system determines the limit output power parameter of the battery according to the current state parameter of the battery in response to the detection result that the state of charge of the battery is larger than a first threshold and the working environment temperature of the battery is within a first temperature interval.

Optionally, the limit output power parameter includes a limit output total power, and the method further includes:

the battery management system detects the output current of the battery;

the battery management system monitors the instantaneous output power of the battery in response to detecting that the output current reaches the output current of the limit mode;

when the battery management system monitors that the accumulated value of the instantaneous output power reaches the limit output total power, the battery management system determines the common output power parameter of the battery according to the current state parameter of the battery;

the battery management system sends the common output power parameter to the vehicle control unit;

the vehicle control unit controls second output power of the battery according to the common output power parameter so as to control the vehicle to be switched to a common output mode;

wherein the first output power is greater than the second output power.

Optionally, the method further includes:

the battery management system monitors the output duration of the battery output power of the vehicle in the common output mode;

the battery management system responds to the switching of the vehicle to a peak output mode and judges whether the output duration reaches a first preset duration or not;

the battery management system responds to the judgment result that the output time length reaches the first preset time length, and determines a peak output power parameter of the battery according to the current state parameter of the battery;

the battery management system sends the peak output power parameter to the vehicle control unit;

the vehicle control unit controls third output power of the battery according to the peak output power parameter;

wherein the first output power is greater than the third output power; the third output power is greater than the second output power.

Optionally, the method further includes:

the battery management system responds to the condition that the vehicle is switched to the limit output mode again, and judges whether the output duration reaches a second preset duration or not;

the battery management system responds to the judgment result that the output time length reaches the second preset time length, and determines the limit output power parameter of the battery according to the current state parameter of the battery;

the battery management system sends the limit output power parameter to the vehicle control unit;

and the vehicle control unit controls the output power of the battery according to the limit output power parameter.

the battery management system responds to the detection of a limit output signal and/or the reception of a limit output instruction, and determines a limit output power parameter of the battery according to the current state parameter of the battery; the limit output signal is a level signal triggered by the closing of a limit gear switch; the limit output instruction is a control instruction sent by the vehicle control unit to the battery management system in response to a level signal triggered by the closing of the limit gear switch.

Optionally, determining the limit output power parameter of the battery according to the current state parameter of the battery includes:

obtaining the state of charge and the working environment temperature of the battery;

inquiring the limit output power parameters under the state of charge and the working environment temperature in a limit output power distribution table; the limit output power distribution table is established by a standard test when a sample battery is used for discharging in the limit output mode in advance, and the model specification of the sample battery is the same as that of the battery.

Optionally, the method further includes:

and after receiving the limit output power parameter, the vehicle control unit controls a signal lamp on an instrument panel to indicate that the vehicle is allowed to work in the limit output mode to be lightened.

A second aspect of the embodiments of the present application provides an electric vehicle battery output power control system, including:

the battery management system is in communication connection with the vehicle control unit;

the battery management system is used for responding to the switching of the vehicle to a limit output mode, determining a limit output power parameter of the battery according to the current state parameter of the battery, and sending the limit output power parameter to the vehicle control unit;

and the vehicle control unit is used for receiving the limit output power parameter and controlling the first output power of the battery according to the limit output power parameter.

Optionally, the battery management system is further configured to detect whether the state of charge of the battery is greater than a first threshold in response to a vehicle switching to a limit output mode, and determine a limit output power parameter of the battery according to the current state parameter of the battery in response to a detection result that the state of charge of the battery is greater than the first threshold.

Optionally, the battery management system is further configured to detect whether the state of charge of the battery is greater than a first threshold and whether the operating environment temperature of the battery is within a first temperature interval in response to a switching of the vehicle to the limit output mode, and determine the limit output power parameter of the battery according to the current state parameter of the battery in response to a detection result that the state of charge of the battery is greater than the first threshold and the operating environment temperature of the battery is within the first temperature interval.

Optionally, the limit output power parameter includes a limit output total power;

the battery management system is further configured to detect an output current of the battery, monitor instantaneous output power of the battery in response to detecting that the output current reaches the output current of the limit mode, determine a common output power parameter of the battery according to a current state parameter of the battery when monitoring that an accumulated value of the instantaneous output power reaches the limit output total power, and send the common output power parameter to the vehicle control unit;

the vehicle control unit is used for receiving the common output power parameter and controlling second output power of the battery according to the common output power parameter so as to control the vehicle to be switched to a common output mode;

wherein the first output power is greater than the second output power.

Optionally, the battery management system is further configured to monitor an output duration of the battery output power of the vehicle in the normal output mode, switch to a peak output mode in response to the vehicle, determine whether the output duration reaches a first preset duration, determine a peak output power parameter of the battery according to the current state parameter of the battery in response to a determination result that the output duration reaches the first preset duration, and send the peak output power parameter to the vehicle controller;

the vehicle control unit is used for receiving the peak output power parameter and controlling the third output power of the battery according to the peak output power parameter;

Optionally, the method further includes:

the battery management system is further used for responding to the condition that the vehicle is switched to the limit output mode again, judging whether the output time length reaches a second preset time length, responding to the judgment result that the output time length reaches the second preset time length, determining a limit output power parameter of the battery according to the current state parameter of the battery, and sending the limit output power parameter to the vehicle control unit;

and the vehicle control unit is used for receiving the limit output power parameter and controlling the output power of the battery according to the limit output power parameter.

Optionally, the system further includes: a limit gear switch;

the limit gear switch is electrically connected with the battery management system and used for inputting a level signal to the battery management system when the limit gear switch is closed; and/or the limit gear switch is electrically connected with the vehicle control unit and is used for inputting a level signal to the vehicle control unit when the vehicle control unit is closed;

the battery management system is used for responding to the detection of a limit output signal and/or the reception of a limit output instruction, and determining a limit output power parameter of the battery according to the current state parameter of the battery; the limit output signal is a level signal input into the battery management system when the limit gear switch is closed; the limit output instruction is a control instruction sent by the vehicle control unit to the battery management system in response to a level signal input by the vehicle control unit when the limit gear switch is closed.

Optionally, the battery management system is further configured to obtain a state of charge and a working environment temperature of the battery, and query the state of charge and the limiting output power parameter at the working environment temperature in a limiting output power distribution table; the limit output power distribution table is established by testing the sample battery in the limit output mode in advance, and the model specification of the sample battery is the same as that of the battery.

Optionally, the system further includes: an instrument panel; the instrument panel is in communication connection with the vehicle control unit;

and the vehicle control unit is further used for controlling the instrument panel to light a signal lamp which is used for indicating that the vehicle is allowed to work in the limit output mode after receiving the limit output power parameter.

A third aspect of embodiments of the present application provides a computer-readable storage medium, on which a computer program is stored, which when executed by a processor, performs the steps in the method according to the first aspect of the present application.

A fourth aspect of the embodiments of the present application provides a vehicle, including:

Compared with the prior art, the method has the following advantages:

when the vehicle is switched to the limit output mode, the battery management system determines a limit output power parameter of the battery according to a current state parameter of the battery, namely a limit output power capability which can be provided by the battery in the current state, and transmits the limit output power parameter to the vehicle control unit, and the vehicle control unit controls the load of the battery according to the limit output power parameter, for example, controls the load power of a driving motor, so that the vehicle works in the limit output mode, and therefore the first output power of the battery is indirectly controlled to meet the high acceleration power or high load operation power requirement. Therefore, the energy type battery can realize the energy supply by discharging outwards according to the limit output power parameter, thereby meeting the high acceleration power requirement of medium and high-end passenger vehicles or the high load operation power requirement of special vehicles.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of an output power control system of a battery according to an embodiment of the present application;

fig. 2 is a flowchart of a method for controlling output power of a battery of an electric vehicle according to an embodiment of the present application;

fig. 3 is a flowchart of a method for controlling output power of a battery of an electric vehicle according to another embodiment of the present application.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, the present application is described in further detail with reference to the accompanying drawings and the detailed description.

In the current industry standard, the "30 min continuous discharge rate" of an energy battery is 1C (C is the unit of the charge and discharge rate of the battery; for example, assuming that the rated capacity of one battery cell is 3000mAh, a current of 3000mA is used for constant current discharge, namely 1C is used for discharge, and min represents one minute), and the "10S peak discharge rate" is about 3C (S represents one second), which can already meet the driving power requirement of a general vehicle.

Of course, when the battery is supplied with power, the magnitude of the discharge current and the magnitude of the output power of the battery are not controlled by the battery itself, but determined by the load and the loss of the external circuit. In an electric vehicle, a load of a battery is mainly a driving motor, and therefore, a load current and a load power of the driving motor of the vehicle generally have the greatest influence on a discharge current level and an output power level of the battery. Therefore, the following description will be made mainly by taking the example of controlling the operation of the driving motor to indirectly control the output power of the battery while the vehicle is running as an example, but it should be particularly noted that this is not a specific limitation of the present application, and those skilled in the art should know that the output power of the battery is substantially determined by the power (including external circuit loss) of all the loads carried by the battery.

After an energy type Battery is calibrated and tested in the industry, a 30min continuous MAP table is calibrated for 30min continuous output power of the energy type Battery, a 10S peak MAP table is calibrated for 10S peak output power, and the tables are stored in a BMS (Battery Management System); the MAP table (power road MAP) is a battery power distribution table, and records output power parameters that the battery can provide when the battery is calibrated under different SOC (State of Charge) and working environment temperatures.

During the running of the vehicle, the BMS monitors current state parameters of the battery in real time, including the SOC of the battery and the operating environment temperature of the battery. When the Vehicle is in the normal output mode, the BMS queries, according to the monitored SOC of the battery and the operating environment temperature of the battery, a 30-min continuous MAP table for a normal output power parameter that the battery can provide in the current state (the current SOC and the operating environment temperature), and sends the normal output power parameter to a VCU (Vehicle control unit), so that the VCU controls the load power of a driving motor (load) according to the received normal output power parameter, thereby causing the driving motor to consume the electric energy of the battery according to the calibrated load power, and further causing the battery to supply energy according to the calibrated normal output power (corresponding discharge current). Similarly, when the vehicle is switched to the peak output mode and the vehicle is allowed to enter the peak output mode, the BMS queries a peak output power parameter that can be provided by the battery in a current state (current SOC and operating environment temperature) according to the monitored SOC of the battery and the operating environment temperature of the battery in a "10S peak MAP table" and sends the peak output power parameter to the VCU, so that the VCU controls the load power of the driving motor (load) according to the received common output power parameter, thereby enabling the driving motor to consume the electric energy of the battery according to the calibrated load power, and further enabling the battery to supply energy according to the calibrated peak output power (corresponding discharge current).

However, the middle-high-end passenger cars have higher sprint acceleration requirements, for example, when the sports cars enter a track for racing, the acceleration performance of the sports cars is directly related to the competition result; special vehicles also have high load operation requirements, for example, when an electric forklift carries goods, the load capacity of the electric forklift is directly related to the carrying capacity of the forklift. No matter the rush acceleration requirement of medium and high-end passenger vehicles or the high load requirement of special vehicles, the pulse power of the driving motor configured by the vehicle is very large, and the battery in the vehicle is required to be discharged outwards at a higher discharge rate to supply energy so as to meet the pulse power of the driving motor, for example, the battery is expected to supply energy outwards at a discharge rate of more than 4C, even 5C, that is, the battery is required to output higher power outwards so as to meet the high-power output requirement, and obviously, the 3C discharge rate in the industry standard is not enough to meet the requirement.

Therefore, how to provide a method for controlling the output power of an energy battery to achieve a higher power output of the energy battery so as to meet the high acceleration power requirement of medium and high end passenger vehicles or the high load operation power requirement of special vehicles is a problem to be solved urgently.

As described above, in the related art, when controlling the output power of the battery in the electric vehicle, the BMS queries the "30 min duration MAP table" and the "10S peak MAP table" in response to the normal output mode or the peak output mode, according to the current state parameter of the battery, to obtain the corresponding normal output power parameter or peak output power parameter representing the power output capability of the battery, and transmits the normal output power parameter and the peak output power parameter to the VCU, and the VCU controls the load power of the driving motor (load) according to the received normal output power parameter or peak output power parameter, thereby controlling the output power of the battery, i.e., the battery is switched between the normal output mode and the peak output mode.

However, during the research process of calibration test on the energy-type battery, the inventor of the present application creatively finds that the energy-type battery can also realize 4C and even 5C rate discharge. Therefore, the inventor selects a certain amount of sample batteries (the sample batteries refer to batteries with the same specification and model as those of batteries assembled by an actual vehicle), and performs recalibration tests by using the sample batteries, so that a 30min continuous MAP table and a 10S peak MAP table are established for the batteries, and a 10S limit MAP table is established for the batteries.

The 30min continuous MAP table is established by a standard test when the sample battery is discharged in a normal output mode, the 10S peak MAP table is established by a standard test when the sample battery is discharged in a peak output mode, and the 10S limit MAP table is established by a standard test when the sample battery is discharged in a limit output mode.

In addition, the 30min continuous MAP table records common output power parameters which can be provided by the battery under different SOC and working environment temperature of the battery, for example, when the vehicle runs at a constant speed, the common output mode is the common output mode, the load power of the driving motor is almost constant, and the battery can bear the load power of the driving motor by supplying energy outwards according to the common output power parameters so as to keep the vehicle running at a constant speed. The "10S peak MAP table" records the peak output power parameter that the battery can provide under different SOCs and operating environment temperatures, for example, when the vehicle is in a normal acceleration driving mode, the load power of the driving motor is increased, and the battery needs to be powered outwards according to the peak output power parameter to carry the load power of the driving motor, so as to implement the normal acceleration driving of the vehicle. The '10S limit MAP table' records the limit output power parameter that the battery can provide under different SOC and working environment temperature, for example, when the vehicle is running at high acceleration, which is the limit output mode, the load power of the driving motor increases sharply, and the battery needs to be powered outwards according to the limit output power parameter to carry the load power of the driving motor, so as to realize high acceleration of the vehicle.

That is, the output power of the battery in the limit output mode is greater than the output power of the battery in the peak output mode, and the output power of the battery in the peak output mode is greater than the output power of the battery in the normal output mode.

Based on this, in the present application, a "10S limit MAP" with higher power performance is added, and a corresponding electric vehicle battery output power control method is proposed to control the output power of the battery in three different output modes (a normal output mode, a peak output mode, and a limit output mode) of the vehicle, so that the energy type can provide higher output power in the limit output mode in addition to the normal mode or the peak output mode of the vehicle, so as to meet the requirement that the vehicle operates in the limit output mode, and provide higher acceleration performance or work load performance for the vehicle. That is, in the method for controlling the output power of the battery of the electric vehicle, the BMS queries the corresponding MAP table ("30 min sustained MAP table", "10S peak MAP table", and "10S limit MAP table") for the corresponding output power parameter according to the output mode of the vehicle and the current state parameter of the battery, and transmits the queried output power parameter to the VCU, so that the VCU controls the output power of the battery according to the received output power parameter.

In order to more clearly explain the technical solution proposed in the present application, a brief description will be given below of an electric vehicle battery output power control system to which the electric vehicle battery output power control method proposed in the present application is applied, and on this basis, a description will be given of an electric vehicle battery output power control method proposed in the present application.

Referring to fig. 1, a schematic structural diagram of a control system for battery output power according to an embodiment of the present application is shown. As shown in fig. 1, the control system is configured in an electric-only vehicle or an electric-plug hybrid vehicle, and the control system at least includes:

battery system 10 and vehicle control unit VCU.

The battery system 10 includes at least a battery E and a battery management system BMS that establishes a communication connection with the VCU via a low-voltage communication interface 103 on the battery system 10 and communicates based on the CAN protocol.

And a voltage acquisition terminal (U) of the BMS receives the terminal voltage of the battery E sensed by the voltage sensor, and a temperature acquisition terminal (T) of the BMS receives the working environment temperature of the battery E sensed by the temperature sensor.

A current sensor 101 may also be included in the battery system 10. The current sensor is connected in series with the output loop of the battery E, for example, is connected in series between the battery E and the negative electrode output end (P2) of the battery E, and is used for collecting the output current of the battery E.

On the basis of the above, the following describes in detail a method for controlling the output power of the battery of the electric vehicle, which is applied to the control system illustrated in fig. 1. Referring to fig. 2, a flow chart of a method for controlling the output power of an electric vehicle battery according to the present application is shown. As shown in fig. 2, the method includes:

s101: the battery management system responds to the vehicle switching to the limit output mode, and determines the limit output power parameter of the battery according to the current state parameter of the battery.

When the vehicle switches to the limit output mode means that the user desires the vehicle to provide high acceleration or perform high-load work.

In an alternative embodiment, the control system shown in fig. 1 further comprises a limit gear switch K1 (in real vehicle applications, also referred to as Boost gear switch, for controlling whether the vehicle is switched to a limit output mode, i.e. Boost power output). The limit output switch K1 is electrically connected to the BMS via the low voltage communication interface 103 on the battery system 10, and the limit output switch K1 is also electrically connected to the VCU.

When the limit gear switch K1 is closed, a level signal is simultaneously input to BMS and VCU. The BMS receives the level signal and receives the limit output signal. After receiving the level signal, the VCU sends a control instruction (i.e., a limit output instruction) carrying a "Boost mode allowed" message to the BMS in response to the level signal. When the BMS detects both the limit output signal and the limit output command, the BMS determines that the vehicle enters the limit output mode.

In an alternative embodiment, in contrast to the embodiment shown in fig. 1, the limit gear switch K1 is only electrically connected to the BMS, which then only detects the level signal (i.e. the limit output signal) which is triggered when the limit output switch K1 is closed. The BMS detects the level signal triggered when the limit output switch K1 is closed, and the BMS determines that the vehicle enters the limit output mode.

In yet another alternative embodiment, unlike the embodiment shown in fig. 1, the limit output switch K1 is only electrically connected to the VCU, and the BMS only receives the limit output command sent by the VCU, which is triggered by the VCU in response to the detection of the level signal input when the limit output switch K1 is closed. The BMS receives the limit output command sent by the VCU, and the BMS determines that the vehicle enters a limit output mode.

By comparison, as shown in the control system shown in fig. 1, the limit gear switch K1 is electrically connected to the BMS and the VCU at the same time, and the BMS finally determines that the vehicle enters the limit output mode only by detecting the limit output signal and receiving the limit output command sent by the VCU at the same time, and performs subsequent steps in the limit output mode (for example, determining the limit output power parameter of the battery according to the current state parameter of the battery), so as to avoid the "Boost mode" start caused by the false alarm of a single signal. Therefore, in a real vehicle application, such an embodiment as shown in fig. 1 is more recommended.

It is of course not excluded that in other embodiments the vehicle is switched to the limit output mode in other ways. For example, a voice recognition model is configured in a vehicle machine of the vehicle, the voice recognition model can recognize a voice command of 'start Boost mode', the vehicle machine sends a switch-to-limit output command to the VCU in response to the recognized voice command, the VCU sends a limit output command to the BMS in response to the switch-to-limit output command, the BMS receives the limit output command sent by the VCU, and the BMS determines that the vehicle enters the limit output mode.

When the BMS detects that the vehicle enters the limit output mode, current state parameters of the battery E, such as a terminal voltage v of the battery E collected by a voltage sensor, an output current i of the battery E collected by a current sensor 101, and an operating environment temperature T of the battery E, are determined, and the SOC of the battery is estimated based on the terminal voltage v. And based on the obtained working environment temperature T and SOC of the battery E, querying a limit output power parameter corresponding to the working environment temperature T and SOC (i.e., representing the capability of the battery E to provide output power at the working environment temperature T and SOC) in a "10S limit MAP table" (i.e., "limit output power distribution table") calibrated for the battery E in advance.

S102: and the battery management system sends the limit output power parameter to the vehicle control unit.

The BMS transmits the limit output power parameter determined from the "10S limit MAP table" to the VCU.

S103: and the vehicle control unit controls the first output power of the battery according to the limit output power parameter.

The VCU controls the power of a driving motor (load) according to the received limit output power parameter, thereby indirectly controlling the limit output power (namely the first output power) of the battery E to meet the requirement of high acceleration or high load operation power and realizing that the battery provides higher output power. The VCU is also used with the instrument panel for indicating the signal lights (Boost instrument lights) that allow the battery to limit the output power. After receiving the parameter of the limit output power, the VCU of the vehicle controller sends a message for lighting a signal lamp to the instrument panel, and controls the signal lamp on the instrument panel to indicate that the vehicle is allowed to work in the limit output mode to be lighted, that is, when the signal lamp is lighted, the VCU prompts a user that the current state allows the battery to output power in the limit output mode, allows high-power work, and the vehicle can provide high acceleration performance or high-load performance. Therefore, the consistency of the data of the '10S limit MAP' received by the VCU and the display of the instrument signal can be ensured, and the customer complaints caused by the inconsistency of the actual performance of the vehicle and the display of the instrument can be reduced.

In the application, an output mode which is specially used for controlling a battery to provide high accelerating power or high-liability working power is configured for an electric vehicle, namely, a limit output mode, when the vehicle is switched to the limit output mode, a battery management system determines a limit output power parameter of the battery according to a current state parameter of the battery, namely, a limit output power capability which can be provided by the battery in a current state, and sends the limit output power parameter to a vehicle control unit, and the vehicle control unit controls a load of the battery according to the limit output power parameter, for example, controls the load power of a driving motor, so that the vehicle works in the limit output mode, and therefore, the first output power of the battery is indirectly controlled to meet the high accelerating power or high-load working power requirement. Therefore, the energy type battery can realize the energy supply by discharging outwards according to the limit output power parameter, thereby meeting the high acceleration power requirement of medium and high-end passenger vehicles or the high load operation power requirement of special vehicles.

However, if the battery is discharged at unreasonably high power, the battery may be overdischarged, accelerating battery aging, which is an irreversible process. That is, discharging the battery at unreasonably high power will greatly shorten the life of the battery, affecting the normal use of the vehicle.

The inventor of the application creatively discovers that the energy type battery can be outwards supplied with energy at a larger discharge rate (namely, outwards supplied with larger output power) as long as the discharge of the energy type battery is reasonably controlled, the service life of the battery is not abnormally damaged, and the normal service life of the battery can be ensured. Specifically, in the calibration test, the inventors found that when the SOC of the energy type battery is greater than a certain threshold (i.e., the first threshold), constant current continuous discharge is performed for 10S at a discharge rate of 4C to 5C, with little effect on the normal life of the battery. Taking the above sample battery as an example, the inventors found that when the SOC of the battery is greater than 60%, the energy type battery can be discharged continuously at a constant current for 10S at a discharge rate of 4C to 5C, and the normal life of the battery is little affected.

Therefore, the inventor of the present application further proposes that when the vehicle switches to the limit output mode, whether the current state parameter of the battery allows the limit output is further detected, and the control system enters the limit output mode in response to the vehicle and controls the first output power output by the battery only when the current state parameter of the battery allows the limit output. The method comprises the following specific steps:

in an alternative embodiment, step S101 includes steps S1011 to S1012.

S1011, the battery management system responds to the vehicle switching to the limit output mode, and detects whether the state of charge of the battery is larger than a first threshold value.

Illustratively, the BMS detects whether the SOC of the battery is estimated to be greater than 60% based on the terminal voltage v.

And S1012, the battery management system determines the limit output power parameter of the battery according to the current state parameter of the battery in response to the detection result that the state of charge of the battery is greater than a first threshold value.

For example, when the BMS detects that the SOC of the battery is estimated to be greater than 60% based on the terminal voltage v, the limit output power parameter of the battery E is determined according to the current state parameters (SOC and T) of the battery E, and the determination method is described in the foregoing related description and will not be described herein again.

In the process of performing a calibration test on a sample battery, the inventor further creatively finds that when the SOC of the energy type battery is greater than a certain threshold (i.e., a first threshold), and within an optimal working environment temperature (i.e., a first temperature interval), constant-current continuous discharge is performed for 10S at a discharge rate of 4C to 5C, and the normal life of the battery is hardly affected. Taking the sample battery as an example, the inventor finds that when the SOC of the battery is more than 60% and the working environment temperature T epsilon of the battery is 20 ℃, 35 ℃, the constant current continuous discharge for 10S at the discharge rate of 4C to 5C has little influence on the normal service life of the battery.

Therefore, the inventor of the present application further proposes that, in an alternative embodiment, step S101 includes step S1013 to step S1014.

S1013, the battery management system responds to the vehicle switching to the limit output mode, and detects whether the state of charge of the battery is larger than a first threshold value and whether the working environment temperature of the battery is in a first temperature interval.

And S1014, the battery management system determines the limit output power parameter of the battery according to the current state parameter of the battery in response to the detection result that the state of charge of the battery is greater than a first threshold and the working environment temperature of the battery is within a first temperature interval.

Different from the above embodiment, when the BMS switches to the limit output mode in response to the vehicle, it is not only detected whether the state of charge SOC of the battery E is greater than 60%, but also detected whether the current operating environment temperature T of the battery E is within the temperature interval [20 ℃, 35 ℃ ], and when it is determined that the SOC of the battery E is greater than 60% and the operating environment temperature T E of the battery is [20 ℃, 35 ℃ ], the limit output power parameter of the battery E is determined according to the current state parameters (SOC and T) of the battery E, and the determination method is not described in detail herein, referring to the related description above.

The first threshold is a critical value allowing the battery to discharge at the limit output power, and can be determined during a calibration test according to the actual performance parameters of the battery. For example, after the energy-type battery is subjected to a calibration test, the first threshold is determined as SOC 60%. The first temperature interval is an optimal working environment temperature range allowing the battery to discharge at the limit output power, and can be determined during a calibration test according to actual performance parameters of the battery. For example, after calibration testing of the energy type battery, the first temperature interval is determined to be [20 ℃, 35 ℃).

During calibration test, the inventor finds that when the SOC of the battery is more than 60% and the working environment temperature T epsilon [20 ℃, 35 ℃) of the battery is high, constant current continuous discharge for 10S is carried out at the discharge rate of 4C-5C, and the normal service life of the battery is hardly influenced. However, in a real vehicle, it is impossible to discharge the battery at a constant current, and it is obviously not reasonable if the discharge time period 10S is taken as the time period for discharging the battery in the limit output mode. In the present application, therefore, the inventors further propose to carry in the limit output power parameter sent by the BMS to the VCU a limit output total power, which characterizes the total power that the battery can provide in the current state and in the limit output mode. Therefore, in an alternative embodiment, the control method further includes steps S103 to S107. The method comprises the following specific steps:

s103, the battery management system detects the output current of the battery.

The BMS acquires the output current i of the battery E in real time through the current sensor 101.

And S104, monitoring the instantaneous output power of the battery by the battery management system in response to detecting that the output current reaches the output current of the limit mode.

When the vehicle is normally operated in the normal output mode, the output current of the battery is relatively small, for example, the output current mentioned above is generally about 1C, and when the vehicle is switched to the limit output mode, the output current of the battery is gradually increased, for example, the output current mentioned above is generally about 4C to 5C, so that the minimum threshold value of the output current in the limit mode, for example, 4C, can be set. When the BMS monitors that the output current i reaches the minimum threshold value of the output current of the limit mode through the current sensor 101, for example, when the output current i of the battery E reaches 4C, the BMS starts monitoring the instantaneous output power of the battery.

And S105, when the battery management system monitors that the accumulated value of the instantaneous output power reaches the limit output total power, the battery management system determines the common output power parameter of the battery according to the current state parameter of the battery.

Because constant current discharge of the battery is impossible, the instantaneous output power of the battery is monitored by an integration method. The BMS monitors the output power of the battery through a power integration method, and specifically monitors the output power through the following formula:

wherein, t₁Is the initial time, t, at which the battery begins to discharge₂Is the current moment when the battery starts to discharge, v is the discharge real-time terminal voltage of the battery, and i is the discharge real-time current of the battery.

When the monitored Paccumulated value reaches the limit output total power P_maxThen, the current state parameters of the battery E are re-determined, such as the terminal voltage v of the battery E collected by the voltage sensor, the output current i of the battery E collected by the current sensor 101, and the operating environment temperature T of the battery E, and the SOC of the battery is estimated based on the terminal voltage v. And based on the obtained working environment temperature T and SOC of the battery E, querying a common output power parameter corresponding to the working environment temperature T and SOC (i.e., representing the capability of the output power that the battery E can provide when the battery E is at the working environment temperature T and SOC) in a "30 min continuous MAP table" (i.e., "common output power distribution table") calibrated for the battery E in advance.

And S106, the battery management system sends the common output power parameter to the vehicle control unit.

The BMS transmits the general output power parameter determined from the '30 min persistent MAP table' to the VCU.

S107, the vehicle controller controls second output power of the battery according to the common output power parameter so as to control the vehicle to be switched to a common output mode; wherein the first output power is greater than the second output power.

The VCU controls the power of the driving motor (load) according to the received normal output power parameter, thereby indirectly controlling the normal output power (i.e., the second output power) of the battery E to meet the power requirement of the normal output mode.

If the battery is discharged for a long time in the high-power mode, not only the aging speed of the battery is accelerated, but also the temperature of the battery itself may be too high, and even the battery may explode. Therefore, the inventor proposes to monitor the discharge condition of the battery through steps S103 to S107, and to notify the VCU to switch the output mode of the vehicle to the normal output mode when the BMS monitors that the integrated value of the instantaneous output power of the battery reaches the limit output total power, so as to protect the life of the battery and driving safety.

In industry standards, the battery is generally discharged stably at about 1C rate in the normal output mode, and is discharged in pulses at about 3C rate in the peak output mode, and may be discharged in pulses at about 4C to 5C rate in the present application. However, the battery can not be discharged continuously for a long time under the multiplying power of 3C to 5C, the battery needs to be switched to stable discharge immediately after pulse discharge, switching from one pulse discharge mode to another pulse discharge mode is not allowed, a certain time interval is needed between every two pulse discharges to ensure the safety of the battery, and the time intervals between every two pulse discharges are different corresponding to the discharge currents with different multiplying powers. For example, it is not allowed to directly switch from the limit output mode to the peak output mode, it is also not allowed to directly switch from the peak output mode to the limit output mode, but only the normal output mode is allowed to switch to the limit output mode or the peak output mode, and after the output power in the limit output mode or the peak output mode meets the requirement, it is switched to the normal output mode again; and the interval duration of switching from the normal output mode to the peak output mode again is shorter than the interval duration of switching from the normal output mode to the limit output mode again.

Taking the sample battery as an example, the time interval between the pulse discharge in the peak output mode and the last pulse discharge is 5S (i.e., the first preset time), and the time interval between the pulse discharge in the limit output mode and the last pulse discharge is 25S (i.e., the second preset time).

Therefore, when the vehicle enters the normal output mode, the BMS further monitors an output period during which the battery outputs power in the normal mode, and decides whether to allow the vehicle to switch from the normal output mode to the peak output mode or the limit output mode according to the different output periods. In an optional embodiment, the method specifically includes the following steps S108 to S116:

and S108, monitoring the output duration of the battery output power of the vehicle in the common output mode by the battery management system.

After step S107, the vehicle enters the normal output mode, and the BMS monitors the output period t of the battery E in the normal output mode.

And S109, responding to the switching of the vehicle to a peak output mode by the battery management system, and judging whether the output time length reaches a first preset time length.

Illustratively, the BMS determines whether an output period t of the battery E in the normal output mode is greater than 5S, i.e., whether an interval period from the last pulse discharge is greater than 5S, in response to the switching of the vehicle from the normal mode to the peak output mode, to decide whether to allow the switching of the vehicle to the peak output mode.

And S110, in response to the judgment result that the output time length reaches the first preset time length, the battery management system determines a peak output power parameter of the battery according to the current state parameter of the battery.

I.e., determining that the interval duration from the last pulse discharge is greater than 5S, allowing the vehicle to switch to the peak output mode, the BMS determines the current state parameters of the battery, e.g., the terminal voltage v of the battery E collected by the voltage sensor, the output current i of the battery E collected by the current sensor 101, and the operating environment temperature T of the battery E, and estimates the SOC of the battery based on the terminal voltage v. And based on the obtained operating environment temperature T and SOC of battery E, querying a "10S peak MAP table" (i.e., "peak output power distribution table") calibrated for battery E in advance for a limit output power parameter corresponding to the operating environment temperature T and SOC (i.e., representing the capability of battery E to provide output power at the operating environment temperature T and SOC).

And S111, the battery management system sends the peak output power parameter to the vehicle control unit.

The BMS sends the peak output power parameter determined from the "10S peak MAP table" to the VCU.

S112, the vehicle controller controls third output power of the battery according to the peak output power parameter; wherein the first output power is greater than the third output power; the third output power is greater than the second output power.

The VCU controls the power of the driving motor (load) according to the received peak output power parameter, thereby indirectly controlling the peak output power (i.e., the third output power) of the battery E to meet the peak output mode power demand.

Further, the following steps S113 to S116 are also included, and it is determined whether the vehicle can enter the limit output mode again, specifically as follows:

and S113, responding to the condition that the vehicle is switched to the limit output mode again by the battery management system, and judging whether the output time length reaches a second preset time length.

Illustratively, the BMS determines whether the output period t of the battery E in the normal output mode is greater than 25S, i.e., whether the interval period from the last pulse discharge is greater than 25S, in response to the vehicle being switched from the normal mode to the limit output mode again, to decide whether to allow the vehicle to be switched to the limit output mode.

And S114, in response to the judgment result that the output time length reaches the second preset time length, the battery management system determines the limit output power parameter of the battery according to the current state parameter of the battery.

That is, it is determined that the interval duration from the last pulse discharge is greater than 25S, the vehicle is allowed to switch to the limit output mode, and the BMS re-determines the limit output power parameter in the current state of the battery according to the current state parameter of the battery, for details, refer to step S101 described above, which is not described herein again.

And S115, the battery management system sends the limit output power parameter to the vehicle control unit.

Please refer to step S102, which is not described herein again.

And S116, controlling the output power of the battery by the vehicle control unit according to the limit output power parameter.

Please refer to step S103, which is not described herein again.

Of course, when step S114 is executed, step S1011 to step S1012 or step S1013 to step S1014 may be executed in order to take safety into consideration, and will not be described again here.

After the limited output mode is switched to, step S103 to step S107 are executed again, so that the battery is switched to the normal output mode again after the total output power of the battery in the limited output mode meets the requirement.

When the battery management system detects a level signal triggered when the limit output switch is closed and/or receives a limit output instruction sent by the vehicle control unit, the battery management system detects whether the state of charge of the battery is greater than a first threshold value and whether the temperature of the working environment of the battery is within a first temperature interval so as to judge whether the current working condition of the battery allows the energy to be supplied to the outside by using a limit output power parameter; and when the detection result shows that the state of charge of the battery is greater than a first threshold value and the temperature of the working environment of the battery is within a first temperature interval, determining that the current working condition of the battery is that the battery is allowed to be supplied with energy outwards by using a limit output power parameter, sending the limit output power parameter to the vehicle control unit by the battery management system, and controlling the load of the battery by the vehicle control unit according to the received limit output power parameter. Therefore, the energy type battery can realize the energy supply by discharging outwards according to the limit output power parameter, thereby meeting the high acceleration power requirement of medium and high-end passenger vehicles or the high load operation power requirement of special vehicles.

The method further comprises the following steps: when the SOC of the battery is detected to be less than 60% and/or the current operating environment temperature T of the battery is not within the temperature interval [20 ℃, 35 ℃) ] indicating that the current battery state does not support the limit output power mode, the BMS determines the general output power parameter of the battery according to the state parameter of the battery and sends the general output power parameter to the VCU, and the VCU controls the output power of the battery according to the general output power parameter, specifically refer to steps S106 to S107.

In an alternative embodiment, in the control system shown in fig. 1, the BMS is also electrically connected to the ignition switch ON of the vehicle via a low voltage communication interface 103 ON the battery system 10. Referring to fig. 3, a flow chart of the electric vehicle battery output power control method of the present application is shown, which illustrates in detail the flow of the control method proposed in the present application from power-up. As shown in fig. 3, the method includes:

after the vehicle starts, i.e., after the ignition switch ON is turned ON, the BMS performs step S201: and detecting a Boost gear switch signal and receiving a start-up Boost message sent by a VCU of the vehicle control unit.

After detecting a Boost gear switch signal and receiving a start Boost message, executing step S202: the BMS detects whether the SOC of the battery is greater than 60% and whether the operating environment temperature T of the battery is between 15 ℃ and 35 ℃. Otherwise, executing step S203: and the BMS determines the peak output power parameter of the battery according to the current state parameter of the battery and sends the peak output power parameter to the VCU.

After power-on is completed, when a limit output mode is not started (namely a Boost gear switch signal is received and/or a start Boost message is received), or the battery does not support the limit output mode (when the SOC of the battery is not more than 60% and/or the current working environment temperature T of the battery is not within a temperature interval [20 ℃ and 35 ℃), or the battery is switched to a peak output mode from a common output mode in the follow-up process, the BMS inquires a peak output power parameter of the battery from a 10S peak MAP table according to the current state parameter of the battery, sends the inquired peak output power parameter to the VCU, and the VCU controls the output power condition output power of the battery according to the peak output power parameter in the received power data of the 10S peak MAP table.

When the actual discharge current of the battery reaches the 10S peak discharge rate (e.g., 3C), the BMS, in response to step S203, performs S204: the BMS begins monitoring the output power of the battery by a power integration method, specifically by the following formula:

wherein, t₁Is the initial time, t, at which the battery begins to discharge in peak mode₂Is the current time when the battery is discharged, v is the discharge real-time terminal voltage of the battery, and i is the discharge real-time current of the battery.

When the monitored P accumulated overflow power reaches the set value P_maxThen, step S205 is executed: the BMS inquires a 30min continuous MAP table according to the current SOC and the working environment temperature T of the battery, the inquired common output power parameter is sent to the VCU, and the VCU continuously reduces the output current of the battery according to the received common output power parameter, so that the battery outputs power according to the common output power parameter.

And performs step S206: monitoring the output duration of the battery for outputting the power according to the common output power parameter, and when the monitored output duration reaches a first preset duration, for example, 5S, allowing the vehicle to switch to the peak output mode, that is, returning to step S203.

When it is detected that the SOC of the battery is greater than 60% and the current operating environment temperature T of the battery is within the temperature interval [20 ℃, 35 ℃), step S207 is executed: the BMS determines a limit output power parameter of the battery according to the current state parameter of the battery, and sends the limit output power parameter to the VCU, and the VCU controls the output power of the battery according to the limit output power parameter; and after receiving the limit output power parameter, the VCU controls a signal lamp (Boost instrument lamp) on the instrument panel for indicating the limit output power of the allowed battery to be lightened.

The BMS inquires a 10S limit MAP table according to the monitored current parameters of the battery, sends power data (namely limit output power parameters) inquired to a 30min continuous MAP table to the VCU, and the VCU controls the output power of the battery according to the continuous output power parameters in the received power data of the 30min continuous MAP table.

Step S208 is performed corresponding to step S207: the BMS monitors instantaneous output power of the battery in response to detecting that the output current of the battery reaches the output current of the limit mode. And when the BMS monitors that the accumulated value of the instantaneous output power reaches the limit output total power, the BMS determines the common output power parameter of the battery according to the current state parameter of the battery. And the BMS sends the ordinary output power parameters to the VCU, and the VCU controls the output power of the battery according to the received ordinary output power parameters so as to control the vehicle to be switched to an ordinary output mode. For details, please refer to the description from step S103 to step S107, which is not repeated herein.

When executed in response to step S208, step S209 is synchronously executed: the output duration of the battery in the normal output mode is monitored, and when the monitored output duration is greater than 5S, the vehicle is allowed to enter the peak output mode (i.e., step S210 and step S212), for details, see the related description of step S108 to step S112 and step S204. When the monitored output duration is greater than 25S, the vehicle is allowed to enter the limit output mode (i.e., step S210), and when the vehicle switches to the limit output mode, the monitored output duration is greater than 25S, the SOC of the battery is greater than 60%, and the operating environment temperature of the battery is between 15 ℃ and 35 ℃, see steps S108 to S112.

Based on the same inventive concept, an embodiment of the present application provides a control system for battery output power. Referring to fig. 1, a schematic structural diagram of a control system for battery output power according to an embodiment of the present application is shown. The electric vehicle battery output power control system includes: the battery management system is in communication connection with the vehicle control unit;

Optionally, the battery management system is further configured to detect whether the state of charge of the battery is greater than a first threshold and whether the operating environment temperature of the battery is within a first temperature interval in response to switching of the vehicle to the limit output mode, and determine the limit output power parameter of the battery according to the current state parameter of the battery in response to a detection result that the state of charge of the battery is greater than the first threshold and the operating environment temperature of the battery is within the first temperature interval.

Optionally, the limit output power parameter comprises a limit output total power;

wherein the first output power is greater than the second output power.

Optionally, the battery management system is further configured to monitor an output duration of the battery output power of the vehicle in the normal output mode, determine whether the output duration reaches a first preset duration in response to switching of the vehicle to a peak output mode, determine a peak output power parameter of the battery according to the current state parameter of the battery in response to the determination result that the output duration reaches the first preset duration, and send the peak output power parameter to the vehicle control unit;

the vehicle control unit is used for receiving the peak output power parameter and controlling third output power of the battery according to the peak output power parameter;

Optionally, the method further comprises:

Optionally, the system further comprises: a limit gear switch;

Optionally, the battery management system is further configured to obtain a state of charge and a working environment temperature of the battery, and query the limit output power parameters under the state of charge and the working environment temperature in a limit output power distribution table; the limit output power distribution table is established by a standard test when a sample battery is used for discharging in the limit output mode in advance, and the model specification of the sample battery is the same as that of the battery.

Optionally, the system further comprises: an instrument panel; the instrument panel is in communication connection with the vehicle control unit;

Based on the same inventive concept, another embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored, which when executed by a processor implements the steps in the method according to any of the above-mentioned embodiments of the present application.

Based on the same inventive concept, another embodiment of the present application provides a vehicle, including: the battery management system is in communication connection with the vehicle control unit;

For the system embodiment, since it is basically similar to the method embodiment, the description is simple, and for the relevant points, refer to the partial description of the method embodiment.

The embodiments in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

As will be appreciated by one of skill in the art, embodiments of the present application may be provided as a method, apparatus, or computer program product. Accordingly, embodiments of the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

Embodiments of the present application are described with reference to flowchart illustrations and/or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing terminal to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing terminal to cause a series of operational steps to be performed on the computer or other programmable terminal to produce a computer implemented process such that the instructions which execute on the computer or other programmable terminal provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While preferred embodiments of the present application have been described, additional variations and modifications of these embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including the preferred embodiment and all changes and modifications that fall within the true scope of the embodiments of the present application.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or terminal equipment comprising the element.

The foregoing detailed description is directed to a method and system for controlling battery output power of an electric vehicle, a storage medium, and a vehicle, which are provided by the present application, and the principles and embodiments of the present application are described herein using specific examples, and the description of the foregoing examples is only provided to help understand the method and the core concept of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. An electric vehicle battery output power control method, characterized by comprising:

2. The method of claim 1, wherein the battery management system determines a limit output power parameter of the battery based on a current state parameter of the battery in response to the vehicle switching to a limit output mode, comprising:

3. The method of claim 1, wherein the battery management system determines a limit output power parameter of the battery based on a current state parameter of the battery in response to the vehicle switching to a limit output mode, comprising:

4. The method of any of claims 1-3, wherein the limiting output power parameter comprises a limiting total output power, the method further comprising:

the battery management system detects the output current of the battery;

wherein the first output power is greater than the second output power.

5. The method of claim 4, further comprising:

6. The method of claim 5, further comprising:

7. The method of any one of claims 1 to 6, wherein the battery management system determining a limit output power parameter of the battery based on a current state parameter of the battery in response to the vehicle switching to a limit output mode comprises:

8. The method according to any one of claims 1 to 7, wherein determining the limit output power parameter of the battery according to the current state parameter of the battery comprises:

9. The method according to any one of claims 1 to 7, further comprising:

10. An electric vehicle battery output power control system, comprising: the battery management system is in communication connection with the vehicle control unit;

11. The system of claim 10, wherein the battery management system is further configured to detect whether the state of charge of the battery is greater than a first threshold in response to the vehicle switching to the limit output mode, and determine the limit output power parameter of the battery according to the current state parameter of the battery in response to the detection result indicating that the state of charge of the battery is greater than the first threshold.

12. The system of claim 10, wherein the battery management system is further configured to detect whether the state of charge of the battery is greater than a first threshold and whether the operating environment temperature of the battery is within a first temperature interval in response to the vehicle switching to the limit output mode, and determine the limit output power parameter of the battery according to the current state parameter of the battery in response to the detection result being that the state of charge of the battery is greater than the first threshold and the operating environment temperature of the battery is within the first temperature interval.

13. The system of any one of claims 10 to 12, wherein the limit output power parameter comprises a limit total output power;

wherein the first output power is greater than the second output power.

14. The system of claim 13, wherein the battery management system is further configured to monitor an output duration of the battery output power of the vehicle in the normal output mode, determine whether the output duration reaches a first preset duration in response to the vehicle switching to a peak output mode, determine a peak output power parameter of the battery according to the current state parameter of the battery in response to the determination that the output duration reaches the first preset duration, and send the peak output power parameter to the vehicle controller;

15. The system of claim 14, wherein the method further comprises:

the battery management system is further used for responding to the condition that the vehicle is switched to the limit output mode again, judging whether the output duration reaches a second preset duration, responding to the judgment result that the output duration reaches the second preset duration, determining a limit output power parameter of the battery according to the current state parameter of the battery, and sending the limit output power parameter to the vehicle control unit;

16. The system of any one of claims 10 to 15, further comprising: a limit gear switch;

17. The system of any one of claims 10 to 16, wherein the battery management system is further configured to obtain a state of charge and an operating ambient temperature of the battery, and look up the limit output power parameter in a limit output power distribution table; the limit output power distribution table is established by testing the sample battery in the limit output mode in advance, and the model specification of the sample battery is the same as that of the battery.

18. The system of any one of claims 10 to 16, further comprising: an instrument panel; the instrument panel is in communication connection with the vehicle control unit;

19. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 9.

20. A vehicle, characterized by comprising: the battery management system is in communication connection with the vehicle control unit;