Vehicle low temperature starting method, device, vehicle and storage medium

Abstract

The present application relates to a low-temperature starting method, device, vehicle and storage medium for a vehicle, including: when there is a low-temperature starting demand, controlling the PTC heater to heat the fuel cell system, and when receiving the actuator ice breaking end signal, obtaining the current temperature and target temperature of the coolant outlet, determining the total required heat for low-temperature starting, and determining the target starting current of the stack according to the total required heat, and controlling the stack to start according to the target starting current, when the temperature of the coolant outlet reaches the target temperature, controlling the PTC heater to stop working, and determining the load current of the stack according to the real-time temperature of the coolant outlet, and controlling the stack according to the load current until the current power of the fuel cell system reaches the idle power, and determining that the vehicle has successfully started at low temperature. Thus, the problem that the related technology fails to accurately control the heat generation, resulting in the failure of low-temperature starting, is solved. The present application can accurately calculate the heat generation and improve the success rate of low-temperature starting.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a low-temperature starting method and device for a vehicle, a vehicle, and a storage medium. Background Art

[0002] The property of a fuel cell is to generate electricity, water, and heat through an electrochemical reaction between hydrogen and oxygen. As a product of the electrochemical reaction, water is both the medium that proton transfer relies on during the power generation process of the fuel cell and the main medium that hinders the transmission of hydrogen and oxygen gases. When the fuel cell is started at or below the freezing point, the reaction product water will freeze during the startup process, hindering the reaction gas from reaching the catalyst surface for an electrochemical reaction. If the water freezes and completely blocks the gas reaction channel, it will cause a low-temperature start failure; at the same time, ice will damage the fuel cell membrane electrode and shorten the life of the fuel cell. Therefore, in order to successfully start the fuel cell at low temperature, it is necessary to accurately monitor the startup temperature so that the heat generated by the fuel cell is sufficient to suppress the freezing rate, and quickly raise the temperature of the stack away from the freezing point of the reaction water to shorten the low-temperature start time.

[0003] Related technologies usually use PTC auxiliary heating or stack self-heating to perform low-temperature cold start of fuel cells. However, related technologies fail to accurately control the heat generation, resulting in low-temperature start failure. The main reasons for low-temperature start failure are:

[0004] (1) The sum of the residual water in the membrane electrode after the stack is purged and the water produced by the electrochemical reaction is greater than the maximum amount of frozen water that the membrane electrode can withstand. The ice completely blocks the reaction channel, resulting in a failure in low-temperature startup (excessive ice will damage the membrane electrode);

[0005] (2) The temperature difference during the start-up of the fuel cell stack is not accurately judged, and the melting rate of the heat generated by the reaction is lower than the freezing rate, resulting in failure of low-temperature start-up or extended low-temperature start-up time. Summary of the invention

[0006] The present application provides a low-temperature starting method, device, vehicle and storage medium for a vehicle to solve the problem that the related technology fails to accurately control the heat generation, resulting in low-temperature starting failure. The present application can accurately calculate the heat generation so that the melting speed of the fuel cell stack is greater than the freezing speed, thereby improving the success rate of low-temperature starting of fuel cell vehicles.

[0007] A first aspect of the present application provides a low-temperature starting method for a vehicle, comprising the following steps:

[0008] When the current vehicle has the low-temperature starting requirement, control the PTC heater to heat the fuel cell system, and upon receiving the ice breaking completion signal of the actuator of the fuel cell system, obtain the current temperature and target temperature of the coolant outlet;

[0009] Determine a total heat requirement for low-temperature startup according to the current temperature and the target temperature, determine a target startup current of the fuel cell stack according to the total heat requirement, control the startup of the fuel cell stack according to the target startup current, and determine whether the temperature of the coolant outlet reaches the target temperature;

[0010] If the temperature of the coolant outlet reaches the target temperature, the PTC heater is controlled to stop working, and the load current of the fuel cell stack is determined according to the real-time temperature of the coolant outlet, and the fuel cell stack is controlled according to the load current until the current power of the fuel cell system reaches the idle power, and it is determined that the low-temperature start of the vehicle is successful.

[0011] Optionally, in some embodiments, determining the target starting current of the fuel cell stack according to the total required heat comprises:

[0012] Obtain the heat generation of the stack, the heat generation of the PTC heater and the maximum water content of the proton exchange membrane;

[0013] The target starting current is calculated according to the total required heat, the heat generated by the fuel cell stack, the heat generated by the PTC heater, and the maximum water content of the proton exchange membrane.

[0014] Optionally, in some embodiments, before calculating the starting current of the stack according to the total required heat, the heat generated by the stack, the heat generated by the PTC heater and the maximum water content of the proton exchange membrane, the method further includes:

[0015] Obtaining the current high-frequency impedance of the battery stack;

[0016] Based on a preset high-frequency impedance-membrane electrode residual water content mapping relationship, the membrane electrode residual water content of the stack is determined according to the current high-frequency impedance, and based on a preset high-frequency impedance-maximum frozen water content mapping relationship, the maximum frozen water content of the stack is determined according to the current high-frequency impedance;

[0017] The maximum water content of the proton exchange membrane is determined according to the difference between the maximum frozen water content and the residual water content of the membrane electrode.

[0018] Optionally, in some embodiments, determining the load current of the fuel cell stack according to the real-time temperature of the coolant outlet further includes:

[0019] Obtaining a load current curve of the battery stack, wherein the load current curve is obtained through a low temperature start calibration test on a battery bench;

[0020] Based on the load current curve, the load current of the fuel cell stack is determined according to the real-time temperature of the coolant outlet.

[0021] Optionally, in some embodiments, after obtaining the current temperature and the target temperature of the coolant outlet, the method further includes:

[0022] Acquire the ambient temperature of the current location of the vehicle, the initial temperature of the coolant outlet, and the first duration of controlling the PTC heater to heat the fuel cell system until receiving the actuator deicing end signal of the fuel cell system, wherein the initial temperature of the coolant outlet is acquired when the current vehicle has the low-temperature starting requirement;

[0023] If the initial temperature of the coolant outlet is greater than the ambient temperature, the temperature rise rate of the coolant outlet is determined according to the initial temperature of the coolant outlet, the current temperature of the coolant outlet and the first time length; otherwise, the temperature rise rate of the coolant outlet is determined according to the ambient temperature, the current temperature of the coolant outlet and the first time length;

[0024] The heating power of the PTC heater is determined according to the temperature rise rate of the coolant outlet.

[0025] Optionally, in some embodiments, after determining that the low-temperature start of the vehicle is successful, the method further includes:

[0026] Obtaining a second time duration from receiving an actuator ice breaking completion signal of the fuel cell system to the temperature of the coolant outlet reaching the target temperature;

[0027] acquiring a third time period from when the temperature of the coolant outlet reaches the target temperature to when determining that the low-temperature start of the vehicle is successful;

[0028] The low-temperature starting performance of the current vehicle is obtained according to the sum of the first time period, the second time period and the third time period.

[0029] A second aspect of the present application provides a low-temperature starting device for a vehicle, comprising:

[0030] An acquisition module, used to control the PTC heater to heat the fuel cell system when the current vehicle has the low-temperature starting requirement, and to acquire the current temperature and target temperature of the coolant outlet when receiving the ice breaking completion signal of the actuator of the fuel cell system;

[0031] a first control module, configured to determine a total heat requirement for low-temperature startup according to the current temperature and the target temperature, determine a target startup current of the fuel cell stack according to the total heat requirement, control startup of the fuel cell stack according to the target startup current, and determine whether the temperature of the coolant outlet reaches the target temperature;

[0032] The second control module is used to control the PTC heater to stop working when the temperature of the coolant outlet reaches the target temperature, and determine the load current of the fuel cell stack according to the real-time temperature of the coolant outlet, and control the fuel cell stack according to the load current until the current power of the fuel cell system reaches the idle power, and it is determined that the low-temperature start of the vehicle is successful.

[0033] Optionally, in some embodiments, the first control module is specifically configured to:

[0034] Obtain the heat generation of the stack, the heat generation of the PTC heater and the maximum water content of the proton exchange membrane;

[0035] The target starting current is calculated according to the total required heat, the heat generated by the fuel cell stack, the heat generated by the PTC heater, and the maximum water content of the proton exchange membrane.

[0036] Optionally, in some embodiments, before calculating the starting current of the stack according to the total required heat, the heat generated by the stack, the heat generated by the PTC heater and the maximum water content of the proton exchange membrane, the first control module is further configured to:

[0037] Obtaining the current high-frequency impedance of the battery stack;

[0038] Based on a preset high-frequency impedance-membrane electrode residual water content mapping relationship, the membrane electrode residual water content of the stack is determined according to the current high-frequency impedance, and based on a preset high-frequency impedance-maximum frozen water content mapping relationship, the maximum frozen water content of the stack is determined according to the current high-frequency impedance;

[0039] The maximum water content of the proton exchange membrane is determined according to the difference between the maximum frozen water content and the residual water content of the membrane electrode.

[0040] Optionally, in some embodiments, the second control module is specifically configured to:

[0041] Obtaining a load current curve of the battery stack, wherein the load current curve is obtained through a low temperature start calibration test on a battery bench;

[0042] Based on the load current curve, the load current of the fuel cell stack is determined according to the real-time temperature of the coolant outlet.

[0043] Optionally, in some embodiments, after obtaining the current temperature and the target temperature of the coolant outlet, the obtaining module is further used to:

[0044] Acquire the ambient temperature of the current location of the vehicle, the initial temperature of the coolant outlet, and the first duration of controlling the PTC heater to heat the fuel cell system until receiving the actuator deicing end signal of the fuel cell system, wherein the initial temperature of the coolant outlet is acquired when the current vehicle has the low-temperature starting requirement;

[0045] If the initial temperature of the coolant outlet is greater than the ambient temperature, the temperature rise rate of the coolant outlet is determined according to the initial temperature of the coolant outlet, the current temperature of the coolant outlet and the first time length; otherwise, the temperature rise rate of the coolant outlet is determined according to the ambient temperature, the current temperature of the coolant outlet and the first time length;

[0046] The heating power of the PTC heater is determined according to the temperature rise rate of the coolant outlet.

[0047] Optionally, in some embodiments, after determining that the low-temperature start of the vehicle is successful, the second control module is further configured to:

[0048] Obtaining a second time duration from receiving an actuator ice breaking completion signal of the fuel cell system to the temperature of the coolant outlet reaching the target temperature;

[0049] acquiring a third time period from when the temperature of the coolant outlet reaches the target temperature to when determining that the low-temperature start of the vehicle is successful;

[0050] The low-temperature starting performance of the current vehicle is obtained according to the sum of the first time period, the second time period and the third time period.

[0051] A third aspect of the present application provides a vehicle, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the low-temperature starting method for the vehicle as described in the above embodiment.

[0052] A fourth aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, the program being executed by a processor to implement the low-temperature starting method for a vehicle as described in the above embodiment.

[0053] Therefore, when there is a need for low-temperature starting, the PTC heater is controlled to heat the fuel cell system, and when the actuator ice breaking end signal is received, the current temperature and target temperature of the coolant outlet are obtained, the total required heat for low-temperature starting is determined, and the target starting current of the stack is determined according to the total required heat, and the stack is started according to the target starting current. When the temperature of the coolant outlet reaches the target temperature, the PTC heater is controlled to stop working, and the load current of the stack is determined according to the real-time temperature of the coolant outlet, and the stack is controlled according to the load current until the current power of the fuel cell system reaches the idle power, and the vehicle is judged to have successfully started at low temperature. Therefore, the problem that the related technology fails to accurately control the heat generation, resulting in the failure of low-temperature starting is solved. The present application can accurately calculate the heat generation, so that the melting speed of the stack is greater than the freezing speed, and the success rate of low-temperature starting of fuel cell vehicles is improved.

[0054] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0056] Figure 1 A flowchart of a low-temperature starting method for a vehicle provided according to an embodiment of the present application;

[0057] Figure 2 A flowchart of a low-temperature starting method for a vehicle provided according to an embodiment of the present application;

[0058] Figure 3 is a block diagram of a low-temperature starting device for a vehicle according to an embodiment of the present application;

[0059] Figure 4 It is a schematic diagram of the structure of a vehicle provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0060] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0061] The following describes the low-temperature starting method, device, vehicle and storage medium of the vehicle of the embodiment of the present application with reference to the accompanying drawings. In view of the problem that the related technology mentioned in the above background technology fails to accurately control the heat generation, resulting in the failure of low-temperature starting, the present application provides a low-temperature starting method for a vehicle, in which the total required heat for low-temperature starting is determined by controlling the PTC heater to heat the fuel cell system when there is a low-temperature starting demand, and when receiving the actuator ice breaking end signal, the current temperature and target temperature of the coolant outlet are obtained, and the target starting current of the stack is determined according to the total required heat, and the stack is controlled to start according to the target starting current. When the temperature of the coolant outlet reaches the target temperature, the PTC heater is controlled to stop working, and the load current of the stack is determined according to the real-time temperature of the coolant outlet, and the stack is controlled according to the load current until the current power of the fuel cell system reaches the idle power, and the vehicle is judged to be successfully started at low temperature. Thus, the problem that the related technology fails to accurately control the heat generation, resulting in the failure of low-temperature starting, the present application can accurately calculate the heat generation, so that the stack melting speed is greater than the freezing speed, and the success rate of low-temperature starting of fuel cell vehicles is improved.

[0062] Specifically, Figure 1 A schematic flow chart of a low-temperature starting method for a vehicle provided in an embodiment of the present application.

[0063] like Figure 1 As shown, the low temperature starting method of the vehicle includes the following steps:

[0064] In step S101, when the current vehicle has a low-temperature starting requirement, the PTC heater is controlled to heat the fuel cell system, and when an actuator deicing end signal of the fuel cell system is received, the current temperature and target temperature of the coolant outlet are obtained.

[0065] It is understandable that fuel cell vehicles have the ability to provide heating by the PTC heater alone. After starting at low temperature, the PTC heater can provide heating. At the same time, the fuel cell auxiliary system actuator is controlled to break the ice. The actuator requires a certain amount of ice-breaking time. Within this time difference, the starting temperature of the stack is difficult to accurately control. The embodiment of the present application can obtain the current temperature of the coolant outlet when receiving the ice-breaking end signal of the actuator of the fuel cell system.

[0066] Specifically, the low-temperature starting method for a vehicle in an embodiment of the present application divides the low-temperature starting into three stages. In the first stage, the actuator breaks ice and the PTC performs heating alone. After the actuator finishes breaking ice, a signal indicating the end of ice breaking is received, and the current temperature and target temperature of the coolant outlet are obtained to determine the total required heat for the second stage through the current temperature and target temperature of the coolant outlet.

[0067] During the actual implementation process, after the vehicle obtains a low-temperature start signal, it sends a high-voltage power supply request signal to the lithium battery to control the PTC to start heating, and sends a low-voltage power supply request signal to control the fuel cell actuator to start breaking ice. After the actuator breaks ice, it obtains a feedback signal, obtains the current temperature of the coolant outlet through the coolant outlet sensor, and determines the target temperature of the coolant outlet. Preferably, the target temperature of the coolant outlet is 0 degrees Celsius.

[0068] Optionally, in some embodiments, after obtaining the current temperature and target temperature of the coolant outlet, it also includes: obtaining the ambient temperature of the current vehicle location, the initial temperature of the coolant outlet, and controlling the PTC heater to heat the fuel cell system until the first duration of receiving the actuator ice breaking end signal of the fuel cell system, wherein the initial temperature of the coolant outlet is collected when the current vehicle has a low-temperature start-up requirement; if the initial temperature of the coolant outlet is greater than the ambient temperature, the temperature rise rate of the coolant outlet is determined based on the initial temperature of the coolant outlet, the current temperature of the coolant outlet and the first duration, otherwise, the temperature rise rate of the coolant outlet is determined based on the ambient temperature, the current temperature of the coolant outlet and the first duration; the heating power of the PTC heater is determined based on the temperature rise rate of the coolant outlet.

[0069] Specifically, in the embodiment of the present application, when the current vehicle has a low-temperature starting requirement, the initial temperature of the coolant outlet is obtained, and the first duration of PTC heating is determined when the actuator ice breaking end signal is received. If the initial temperature of the coolant outlet is higher than the ambient temperature, the first temperature difference between the current temperature of the coolant outlet and the initial temperature of the coolant outlet is determined, and the temperature rise rate of the coolant outlet is obtained by dividing the first temperature difference by the first duration; if the initial temperature of the coolant outlet is less than or equal to the ambient temperature, the second temperature difference between the current temperature of the coolant outlet and the ambient temperature is determined, and the temperature rise rate of the coolant outlet is obtained by dividing the second temperature difference by the first duration. After determining the temperature rise rate of the coolant outlet, the heating power of the PTC heater is determined according to the temperature rise rate of the coolant outlet. Through the above-mentioned technical means, the embodiment of the present application can reduce the influence of ambient temperature on the PTC heating power.

[0070] In step S102, the total required heat for low-temperature startup is determined based on the current temperature and the target temperature, and the target starting current of the fuel cell stack is determined based on the total required heat. The startup of the fuel cell stack is controlled based on the target starting current, and it is determined whether the temperature of the coolant outlet reaches the target temperature.

[0071] It should be noted that after the actuator breaks the ice, the vehicle enters the second stage of low-temperature start. In the second stage, the PTC and the battery stack are used for joint heating. The total required heat for low-temperature start is determined by the current temperature and target temperature of the coolant outlet obtained in the first stage. The target starting current of the battery stack is calculated based on the total required heat, and the battery stack start is controlled according to the target starting current, so as to accurately determine the starting temperature of the low-temperature start and accurately calculate the calorific value, so that the heat generated by the fuel cell is sufficient to suppress the freezing speed, and quickly increase the temperature of the battery stack to break away from the freezing point of the reaction water, thereby shortening the low-temperature start time.

[0072] Specifically, the total heat demand is:

[0073] Q 需 =C P *m 总 *(T 2 -T 1 ); (1)

[0074] Among them, Q 需 is the total heat demand, C P is the total specific heat capacity of the battery stack and small cycle components, m 总 is the total mass of the battery stack and small cycle components, T 2 is the target temperature, T 1 is the current temperature.

[0075] Furthermore, in some embodiments, the target starting current of the fuel cell stack is determined based on the total heat requirement, including: obtaining the heat generation of the fuel cell stack, the heat generation of the PTC heater and the maximum water content of the proton exchange membrane; and calculating the target starting current based on the total heat requirement, the heat generation of the fuel cell stack, the heat generation of the PTC heater and the maximum water content of the proton exchange membrane.

[0076] In the second stage, the PTC and the stack are heated together, so

[0077] Q 需 =Q stack +Q ptc ; (2)

[0078] Among them, Q stack is the heat generated by the battery stack, Q ptc is the heat generated by the PTC.

[0079] The heat generation of the battery stack is:

[0080]

[0081] Among them, Q stack is the heat generated by the battery stack, N is the number of cells, V 0 is the stack voltage when the current power of the fuel cell system reaches the idle power, and I is the starting current of the stack.

[0082] In the second stage, the heat generation of the PTC heater is:

[0083] Q ptc =P v *(tt 0 ); (4)

[0084] Among them, Q ptc P is the heat generated by the PTC heater. v is the heating power of the PTC heater, t 0 To obtain the time corresponding to the current temperature of the coolant outlet, t is the time corresponding to reaching the target temperature.

[0085] Furthermore, in some embodiments, before calculating the starting current of the fuel cell stack based on the total required heat, the heat generated by the fuel cell stack, the heat generated by the PTC heater and the maximum water content of the proton exchange membrane, it also includes: obtaining the current high-frequency impedance of the fuel cell stack; based on a preset mapping relationship of high-frequency impedance-residual water content of the membrane electrode, determining the residual water content of the membrane electrode of the fuel cell stack according to the current high-frequency impedance, and based on a preset mapping relationship of high-frequency impedance-maximum freezing water content, determining the maximum freezing water content of the fuel cell stack according to the current high-frequency impedance; determining the maximum water content of the proton exchange membrane according to the difference between the maximum freezing water content and the residual water content of the membrane electrode.

[0086] It can be understood by those skilled in the art that when the stack satisfies the maximum frozen water content>membrane electrode residual water content+fuel cell water production, the ice melting rate is greater than the freezing rate. At this time, the low-temperature start of the stack is not likely to fail due to water freezing. On the contrary, if the stack does not satisfy the maximum frozen water content>membrane electrode residual water content+fuel cell water production, the ice melting rate is less than the freezing rate. At this time, water freezing may completely block the gas reaction channel, resulting in a low-temperature start failure. If the sum of the membrane electrode residual water and the electrochemical reaction water production is greater than the maximum amount of frozen water that the membrane electrode can withstand, it will cause ice to completely block the reaction channel, resulting in a low-temperature start failure. The embodiment of the present application can make the fuel cell at the best performance by controlling the maximum water content of the proton exchange membrane. At this water content, the proton conductivity of the membrane is optimal, which can ensure the efficient operation of the battery.

[0087] It should be noted that the embodiment of the present application can obtain in advance through a test bench the mapping relationship between the high-frequency impedance of the fuel cell stack under low-temperature sensitivity and the residual water content of the membrane electrode and the mapping relationship between the preset high-frequency impedance and the maximum freezing water content to obtain the mapping relationship between the preset high-frequency impedance and the residual water content of the membrane electrode and the mapping relationship between the preset high-frequency impedance and the maximum freezing water content.

[0088] Specifically, the embodiment of the present application can obtain the current high-frequency impedance of the fuel cell stack, and obtain the membrane electrode residual water content and the maximum frozen water content based on the high-frequency impedance, the preset high-frequency impedance-membrane electrode residual water content mapping relationship, and the preset high-frequency impedance-maximum frozen water content mapping relationship.

[0089]

[0090] The water output of the battery stack is:

[0091]

[0092] Among them, m H20 is the water production of the battery stack, t is the target time, t0 is the initial time, N is the number of cells, I is the starting current, F is the Faraday constant, M H20 is the molar mass of the product water.

[0093] The maximum water content of proton exchange membrane is:

[0094]

[0095] in, is the maximum water content of the proton exchange membrane, λm is the water content coefficient of the proton exchange membrane, β is the reverse osmosis water coefficient of the proton exchange membrane, t 0 is the time corresponding to the current temperature of the coolant outlet, t is the time corresponding to the target temperature, N is the number of cells, is the molar mass of water, I is the starting current of the battery stack, and F is the Faraday constant.

[0096] By combining formulas (1)(2)(3)(4) and (7), the starting current I of the battery stack and the time t corresponding to reaching the target temperature can be calculated.

[0097] In step S103, if the temperature of the coolant outlet reaches the target temperature, the PTC heater is controlled to stop working, and the load current of the fuel cell stack is determined according to the real-time temperature of the coolant outlet, and the fuel cell stack is controlled according to the load current until the current power of the fuel cell system reaches the idle power, and it is determined that the low-temperature start of the vehicle is successful.

[0098] It is understandable that when the temperature of the coolant reaches 0 degrees, there is no risk of the coolant freezing. At this time, the PTC heating can be stopped to save energy.

[0099] Specifically, in the second stage of low-temperature starting, the PTC and the battery stack are heated together, and when the ambient temperature is higher than 0 degrees, the PTC heating is stopped. After the PTC heater stops working, the vehicle enters the third stage of low-temperature starting. In the third stage, the battery stack is heated alone until the vehicle reaches idle power.

[0100] Furthermore, in some embodiments, determining the load current of the fuel cell stack according to the real-time temperature of the coolant outlet also includes: obtaining a load current curve of the fuel cell stack, wherein the load current curve is obtained by a low-temperature start-up calibration test on a battery bench; and determining the load current of the fuel cell stack according to the real-time temperature of the coolant outlet based on the load current curve.

[0101] Specifically, in order to optimize the heating performance of the battery stack, the embodiment of the present application can determine the load current curve through the battery bench low temperature start calibration test, obtain the real-time temperature of the coolant outlet, determine the load current of the battery stack according to the real-time temperature of the coolant outlet and the load current curve, and control the battery stack to heat separately according to the load current until the vehicle reaches the idle power. Among them, there are many ways to perform low temperature start calibration tests on battery benches in the related art, and no specific limitation is made here to avoid redundancy.

[0102] Therefore, the embodiment of the present application can accurately monitor the starting temperature of the fuel cell stack heating, so that the heat generated by the fuel cell is sufficient to suppress the freezing rate, and quickly increase the temperature of the fuel cell stack to break away from the freezing point of the reaction water, shorten the low-temperature start-up time, increase the success rate of the vehicle's low-temperature start-up, and improve the heating performance of the fuel cell stack.

[0103] Optionally, in some embodiments, after determining that the vehicle has successfully started at a low temperature, it also includes: obtaining a second time duration from when a signal from the fuel cell system's actuator ice-breaking ends to when the temperature at the coolant outlet reaches a target temperature; obtaining a third time duration from when the temperature at the coolant outlet reaches the target temperature to when determining that the vehicle has successfully started at a low temperature; and obtaining the current vehicle's low temperature starting performance based on the sum of the first time duration, the second time duration, and the third time duration.

[0104] It is understandable that if the vehicle has difficulty starting or the starting time increases significantly at low temperatures, it may be a sign of deteriorating vehicle performance and requires inspection and maintenance. The embodiment of the present application can obtain the duration of the vehicle's low-temperature start-up and determine the current vehicle's low-temperature starting performance based on the duration of the vehicle's low-temperature start-up.

[0105] Specifically, the low-temperature starting method of the embodiment of the present application is divided into three stages. In the first stage, from the start of the low-temperature start to the receipt of the actuator ice-breaking end signal of the fuel cell system, the PTC is used for heating alone. In the second stage, from the moment the actuator ice-breaking end signal of the fuel cell system is received to the moment the coolant outlet temperature reaches the target temperature, the PTC and the fuel cell stack are used for heating together. In the third stage, from the moment the coolant outlet temperature reaches the target temperature to the moment the vehicle power reaches the idle power, the fuel cell stack is used for heating alone.

[0106] The embodiment of the present application can obtain the first time duration from controlling the PTC heater to heat the fuel cell system until the actuator ice-breaking end signal of the fuel cell system is received (i.e., the first stage heating time duration), the second time duration from the actuator ice-breaking end signal of the fuel cell system to the temperature of the coolant outlet reaching the target temperature (i.e., the second stage heating time duration), and the third time duration from obtaining the coolant outlet temperature reaching the target temperature to determining that the vehicle low-temperature start is successful (i.e., the third stage heating time duration), and determine the low-temperature starting performance of the current vehicle based on the sum of the first time duration, the second time duration, and the third time duration, wherein there are many ways to determine the low-temperature starting performance of the current vehicle, for example, judging whether the sum of the first time duration, the second time duration, and the third time duration is in a preset performance threshold interval, if the sum of the first time duration, the second time duration, and the third time duration is in the preset performance threshold interval, then the low-temperature starting performance of the vehicle is judged to be normal, otherwise, the low-temperature starting performance of the vehicle is judged to be abnormal. For another example, the embodiment of the present application obtains the total low-temperature start time by the sum of the first time, the second time, and the third time, and obtains the low-temperature start time of the same type of vehicles through the Internet of Vehicles, and determines the ranking of the total low-temperature start time of the current vehicle in the low-temperature start time of the same type of vehicles. If the ranking is in the first interval, it is determined that the low-temperature start performance of the current vehicle is excellent; if the ranking is in the second interval, it is determined that the low-temperature start performance of the current vehicle is medium; if the ranking is in the third interval, it is determined that the low-temperature start performance of the current vehicle is poor.

[0107] After determining the low-temperature starting performance of the current vehicle, the vehicle can be optimized according to the low-temperature starting performance of the current vehicle. For example, the stage to be optimized in the three stages of low-temperature starting is analyzed according to the first duration, the second duration and the third duration, and the stage to be optimized is optimized.

[0108] In order to enable relevant technical personnel in the field to further understand the low-temperature starting method of a vehicle according to the embodiment of the present application, it is described in detail below in conjunction with specific embodiments.

[0109] like Figure 2 As shown, Figure 2 The present invention is a flow chart of a low-temperature starting method for a vehicle provided according to an embodiment of the present application.

[0110] S0, when the vehicle has a low-temperature starting requirement, obtain the ambient temperature of the current vehicle location and the initial temperature of the coolant outlet, and determine the heating power of the PTC heater according to the ambient temperature and the initial temperature of the coolant outlet.

[0111] S1, the vehicle enters the first stage of low-temperature starting, controls the PTC heater to heat with heating power, and controls the actuator to break ice.

[0112] S2, obtains a signal indicating that the actuator has finished breaking ice, and obtains the current temperature and target temperature of the coolant outlet, determines the total heat requirement of the vehicle according to the current temperature and target temperature of the coolant outlet, and determines the target starting current of the battery according to the total heat requirement.

[0113] The target starting current is calculated as follows:

[0114] Determine the total heat requirement based on the target temperature and current temperature of the coolant outlet.

[0115] Q 需 =C P *m 总 *(T 2 -T 1 );

[0116] The total required heat is generated by PTC and the battery stack.

[0117] Q 需 =Q stack +Q ptc ;

[0118] The heat generation of the battery stack is:

[0119]

[0120] The heat generation of the PTC heater is:

[0121] Q ptc =P v *(tt 0 );

[0122] The maximum water content of proton exchange membrane is:

[0123]

[0124] Combining the above formulas, we can obtain the target starting current I and the time to reach the target temperature.

[0125] S3, the vehicle enters the second stage of low-temperature starting, and controls the PTC and the battery stack to heat together, wherein the PTC heater heats with the heating power, and the battery stack heats with the target starting current.

[0126] S4, when the temperature of the coolant outlet reaches the target temperature, the vehicle enters the third stage of low-temperature start-up, stops the PTC heater for heating, obtains the real-time temperature of the coolant outlet, determines the load current of the battery stack based on the real-time temperature, and controls the battery stack to heat alone with the load current until the vehicle power reaches the idle power.

[0127] According to the low-temperature starting method of the vehicle proposed in the embodiment of the present application, when there is a low-temperature starting demand, the PTC heater is controlled to heat the fuel cell system, and when the actuator ice breaking end signal is received, the current temperature and target temperature of the coolant outlet are obtained to determine the total required heat for low-temperature starting, and the target starting current of the stack is determined according to the total required heat, and the stack is started according to the target starting current. When the temperature of the coolant outlet reaches the target temperature, the PTC heater is controlled to stop working, and the load current of the stack is determined according to the real-time temperature of the coolant outlet, and the stack is controlled according to the load current until the current power of the fuel cell system reaches the idle power, and the vehicle is judged to have successfully started at low temperature. Thus, the problem that the related technology fails to accurately control the heat generation, resulting in the failure of low-temperature starting is solved. The present application can accurately calculate the heat generation, so that the stack melting speed is greater than the freezing speed, and the success rate of low-temperature starting of fuel cell vehicles is improved.

[0128] Next, the low-temperature starting device for a vehicle proposed in accordance with an embodiment of the present application will be described with reference to the accompanying drawings.

[0129] Figure 3 It is a block diagram of a low-temperature starting device for a vehicle according to an embodiment of the present application.

[0130] like Figure 3 As shown, the low-temperature starting device 10 of the vehicle includes: an acquisition module 100 , a first control module 200 and a second control module 300 .

[0131] Among them, the acquisition module 100 is used to control the PTC heater to heat the fuel cell system when the current vehicle has a low-temperature start-up requirement, and to obtain the current temperature and target temperature of the coolant outlet when receiving the actuator ice breaking end signal of the fuel cell system.

[0132] The first control module 200 is used to determine the total required heat for low-temperature startup based on the current temperature and the target temperature, determine the target starting current of the fuel cell stack based on the total required heat, control the startup of the fuel cell stack based on the target starting current, and determine whether the temperature of the coolant outlet reaches the target temperature.

[0133] The second control module 300 is used to control the PTC heater to stop working when the temperature of the coolant outlet reaches the target temperature, and determine the load current of the fuel cell stack according to the real-time temperature of the coolant outlet, and control the fuel cell stack according to the load current until the current power of the fuel cell system reaches the idle power, and it is determined that the low-temperature start of the vehicle is successful.

[0134] Optionally, in some embodiments, the first control module 200 is specifically used to: obtain the heat generation of the fuel cell stack, the heat generation of the PTC heater and the maximum water content of the proton exchange membrane; calculate the target starting current according to the total required heat, the heat generation of the fuel cell stack, the heat generation of the PTC heater and the maximum water content of the proton exchange membrane.

[0135] Optionally, in some embodiments, before calculating the starting current of the fuel cell stack based on the total required heat, the heat generated by the fuel cell stack, the heat generated by the PTC heater and the maximum water content of the proton exchange membrane, the first control module 200 is also used to: obtain the current high-frequency impedance of the fuel cell stack; determine the residual water content of the membrane electrode of the fuel cell stack according to the current high-frequency impedance based on a preset mapping relationship between high-frequency impedance and residual water content of the membrane electrode, and determine the maximum frozen water content of the fuel cell stack according to the current high-frequency impedance based on a preset mapping relationship between high-frequency impedance and maximum frozen water content; determine the maximum water content of the proton exchange membrane according to the difference between the maximum frozen water content and the residual water content of the membrane electrode.

[0136] Optionally, in some embodiments, the second control module 300 is specifically used to: obtain a load current curve of the fuel cell stack, wherein the load current curve is obtained through a low-temperature start-up calibration test on a battery bench; based on the load current curve, determine the load current of the fuel cell stack according to the real-time temperature of the coolant outlet.

[0137] Optionally, in some embodiments, after obtaining the current temperature and target temperature of the coolant outlet, the acquisition module 100 is further used to: obtain the ambient temperature of the current vehicle location, the initial temperature of the coolant outlet, and control the PTC heater to heat the fuel cell system until the first duration of time when the actuator ice breaking end signal of the fuel cell system is received, wherein the initial temperature of the coolant outlet is collected when the current vehicle has a low-temperature start-up requirement; if the initial temperature of the coolant outlet is greater than the ambient temperature, the temperature rise rate of the coolant outlet is determined based on the initial temperature of the coolant outlet, the current temperature of the coolant outlet and the first duration, otherwise, the temperature rise rate of the coolant outlet is determined based on the ambient temperature, the current temperature of the coolant outlet and the first duration; the heating power of the PTC heater is determined based on the temperature rise rate of the coolant outlet.

[0138] Optionally, in some embodiments, after determining that the vehicle has successfully started at a low temperature, the second control module 300 is further used to: obtain a second time duration from when a signal indicating that the actuator ice breaking of the fuel cell system has ended to when the temperature of the coolant outlet reaches a target temperature; obtain a third time duration from when the temperature of the coolant outlet reaches the target temperature to when determining that the vehicle has successfully started at a low temperature; and obtain the low temperature starting performance of the current vehicle based on the sum of the first time duration, the second time duration, and the third time duration.

[0139] It should be noted that the above explanation of the embodiment of the low-temperature starting method for a vehicle is also applicable to the low-temperature starting device for a vehicle of this embodiment, and will not be repeated here.

[0140] According to the low-temperature starting device of the vehicle proposed in the embodiment of the present application, when there is a low-temperature starting demand, the PTC heater is controlled to heat the fuel cell system, and when the actuator ice breaking end signal is received, the current temperature and target temperature of the coolant outlet are obtained to determine the total required heat for low-temperature starting, and the target starting current of the stack is determined according to the total required heat, and the stack is started according to the target starting current. When the temperature of the coolant outlet reaches the target temperature, the PTC heater is controlled to stop working, and the load current of the stack is determined according to the real-time temperature of the coolant outlet, and the stack is controlled according to the load current until the current power of the fuel cell system reaches the idle power, and the vehicle is judged to have successfully started at low temperature. Thus, the problem that the related technology fails to accurately control the heat generation, resulting in the failure of low-temperature starting is solved. The present application can accurately calculate the heat generation, so that the stack melting speed is greater than the freezing speed, and the success rate of low-temperature starting of fuel cell vehicles is improved.

[0141] Figure 4 A schematic diagram of the structure of a vehicle provided in an embodiment of the present application. The vehicle may include:

[0142] Memory 401 , processor 402 , and a computer program stored in the memory 401 and executable on the processor 402 .

[0143] When the processor 402 executes the program, the low-temperature starting method for the vehicle provided in the above embodiment is implemented.

[0144] Furthermore, the vehicle also includes:

[0145] The communication interface 403 is used for communication between the memory 401 and the processor 402 .

[0146] The memory 401 is used to store computer programs that can be executed on the processor 402 .

[0147] The memory 401 may include a high-speed RAM (Random Access Memory) memory, and may also include a non-volatile memory, such as at least one disk memory.

[0148] If the memory 401, the processor 402 and the communication interface 403 are implemented independently, the communication interface 403, the memory 401 and the processor 402 can be connected to each other through a bus and communicate with each other. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 4 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0149] Optionally, in a specific implementation, if the memory 401, the processor 402 and the communication interface 403 are integrated on a chip, the memory 401, the processor 402 and the communication interface 403 can communicate with each other through an internal interface.

[0150] The processor 402 may be a CPU (Central Processing Unit), or an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present application.

[0151] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned low-temperature starting method for a vehicle.

[0152] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0153] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0154] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0155] It should be understood that the various parts of the present application can be implemented in hardware, software, firmware or a combination thereof. In the above embodiment, the N steps or methods can be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or a combination thereof: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array, a field programmable gate array, etc.

[0156] A person skilled in the art may understand that all or part of the steps in the above-mentioned embodiment method may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0157] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for starting a vehicle at low temperature, characterized in that: The following steps are involved: When the current vehicle has the low-temperature starting requirement, control the PTC heater to heat the fuel cell system, and upon receiving the ice breaking completion signal of the actuator of the fuel cell system, obtain the current temperature and target temperature of the coolant outlet; Determine a total heat requirement for low-temperature startup according to the current temperature and the target temperature, determine a target startup current of the fuel cell stack according to the total heat requirement, control the startup of the fuel cell stack according to the target startup current, and determine whether the temperature of the coolant outlet reaches the target temperature; as well as If the temperature of the coolant outlet reaches the target temperature, the PTC heater is controlled to stop working, and the load current of the fuel cell stack is determined according to the real-time temperature of the coolant outlet, and the fuel cell stack is controlled according to the load current until the current power of the fuel cell system reaches the idle power, and it is determined that the low-temperature start of the vehicle is successful, wherein, Determining the target starting current of the fuel cell stack according to the total required heat comprises: Obtain the heat generation of the stack, the heat generation of the PTC heater and the maximum water content of the proton exchange membrane; The target starting current is calculated according to the total required heat, the heat generated by the fuel cell stack, the heat generated by the PTC heater, and the maximum water content of the proton exchange membrane.

2. The method according to claim 1, characterized in that Before calculating the starting current of the stack according to the total required heat, the heat generated by the stack, the heat generated by the PTC heater and the maximum water content of the proton exchange membrane, the method further includes: Obtaining the current high-frequency impedance of the battery stack; Based on a preset high-frequency impedance-membrane electrode residual water content mapping relationship, the membrane electrode residual water content of the stack is determined according to the current high-frequency impedance, and based on a preset high-frequency impedance-maximum frozen water content mapping relationship, the maximum frozen water content of the stack is determined according to the current high-frequency impedance; The maximum water content of the proton exchange membrane is determined according to the difference between the maximum frozen water content and the residual water content of the membrane electrode.

3. The method according to claim 1, characterized in that The method of determining the load current of the stack according to the real-time temperature of the coolant outlet further includes: Obtaining a load current curve of the battery stack, wherein the load current curve is obtained through a low temperature start calibration test on a battery bench; Based on the load current curve, the load current of the fuel cell stack is determined according to the real-time temperature of the coolant outlet.

4. The method according to claim 1, characterized in that: After obtaining the current temperature and the target temperature of the coolant outlet, the method further includes: Acquire the ambient temperature of the current location of the vehicle, the initial temperature of the coolant outlet, and the first duration of controlling the PTC heater to heat the fuel cell system until receiving the actuator deicing end signal of the fuel cell system, wherein the initial temperature of the coolant outlet is acquired when the current vehicle has the low-temperature starting requirement; If the initial temperature of the coolant outlet is greater than the ambient temperature, the temperature rise rate of the coolant outlet is determined according to the initial temperature of the coolant outlet, the current temperature of the coolant outlet and the first time length; otherwise, the temperature rise rate of the coolant outlet is determined according to the ambient temperature, the current temperature of the coolant outlet and the first time length; The heating power of the PTC heater is determined according to the temperature rise rate of the coolant outlet.

5. The method according to claim 4, characterized in that After determining that the low-temperature start of the vehicle is successful, the method further includes: Obtaining a second time duration from receiving an actuator ice breaking completion signal of the fuel cell system to the temperature of the coolant outlet reaching the target temperature; acquiring a third time period from when the temperature of the coolant outlet reaches the target temperature to when determining that the low-temperature start of the vehicle is successful; The low-temperature starting performance of the current vehicle is obtained according to the sum of the first time period, the second time period and the third time period.

6. A low-temperature starting device for a vehicle, characterized in that: include: An acquisition module, used to control the PTC heater to heat the fuel cell system when the current vehicle has the low-temperature starting requirement, and to acquire the current temperature and target temperature of the coolant outlet when receiving the ice breaking completion signal of the actuator of the fuel cell system; a first control module, configured to determine a total heat requirement for low-temperature startup according to the current temperature and the target temperature, determine a target startup current of the fuel cell stack according to the total heat requirement, control startup of the fuel cell stack according to the target startup current, and determine whether the temperature of the coolant outlet reaches the target temperature; The second control module is used to control the PTC heater to stop working when the temperature of the coolant outlet reaches the target temperature, and determine the load current of the fuel cell stack according to the real-time temperature of the coolant outlet, and control the fuel cell stack according to the load current until the current power of the fuel cell system reaches the idle power, and determine that the low-temperature start of the vehicle is successful, wherein, The first control module is specifically used to: Obtain the heat generation of the stack, the heat generation of the PTC heater and the maximum water content of the proton exchange membrane; The target starting current is calculated according to the total required heat, the heat generated by the fuel cell stack, the heat generated by the PTC heater, and the maximum water content of the proton exchange membrane.

7. A vehicle, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the low-temperature starting method for a vehicle according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the low-temperature starting method for a vehicle according to any one of claims 1 to 5.

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