Fuel cell low temperature start-up control method, control device, readable storage medium

Abstract

The application discloses a fuel cell low-temperature starting control method, a control device and a readable storage medium. The method comprises the following steps: S1, acquiring the minimum power FCU_P of a fuel cell system in real time fcsmin , the maximum allowed continuous charging power BMS_P of a power battery maxchg , the heating film heating power BMS_P of the power battery heat , and the real-time power VCU_P of a vehicle auxiliary system aux ; S2, judging whether FCU_P fcsmin <BMS_P maxchg +BMS heat +VCU_P aux -δ1 is true, wherein δ1 is a designed reserved power difference; if true, executing S3; if not true, executing S4 and re-judging whether the above condition is true until FCU_P fcsmin <BMS_P maxchg +BMS heat +VCU_P aux -δ1 is true, and then executing S5; S2, sending a fuel cell system starting enable signal to the FCU and sending a battery thermal management electronic three-way valve opening enable signal to the BMS; S3, sending a fuel cell non-starting enable signal and a fuel cell PTC heater starting enable signal to the FCU and sending a battery thermal management electronic three-way valve opening enable to the BMS; and S4, sending a fuel cell system starting enable signal to the FCU. The application has small damage to the power battery during low-temperature starting.

Description

Technical Field

[0001] This invention relates to the field of hydrogen fuel cell vehicles, specifically to a method, control device, and readable storage medium for controlling the low-temperature start-up of a hydrogen fuel cell vehicle. Background Technology

[0002] Fuel cell vehicles are clean and pollution-free, and have now entered the commercial demonstration operation stage. Due to the soft output characteristics and slow dynamic response of fuel cells, most fuel cell vehicles adopt a hybrid power system consisting of a fuel cell and a power battery.

[0003] A power battery is a battery system that stores chemical energy internally and can directly provide electrical energy to an electric motor. A fuel cell relies on externally supplied fuel and reacts it with oxygen to generate electrical energy. The electrical energy generated by a hydrogen fuel cell can be directly converted into mechanical energy to drive the vehicle, or it can be stored in a power battery for later use.

[0004] Low-temperature start-up is one of the main factors affecting the commercialization of fuel cell vehicles. It refers to the ability of a fuel cell vehicle to start successfully at temperatures below 0°C and to rapidly raise the internal temperature of the fuel cell to 70-80°C to meet normal operating performance requirements.

[0005] When a fuel cell vehicle starts in low temperatures, it is powered by the power battery and uses an electric heater to heat the cooling medium in the fuel cell cooling pipe, thus achieving low-temperature start-up. For example, Chinese Patent Application No. 201611199616.1 discloses a fuel cell system including a fuel cell and a fuel cell cooling pipeline. The fuel cell cooling pipeline is equipped with an electric heater for heating the cooling medium in the fuel cell cooling pipeline during fuel cell start-up. The electric heater is connected to the power battery to draw power from it. The fuel cell system also includes a heat exchanger for heat preservation of the power battery. The first set of ports of the heat exchanger is connected in series in the fuel cell cooling pipeline, and the second set of ports is connected in series in the power battery cooling pipeline. After the fuel cell is operating normally, when the power battery temperature is low, the high-temperature cooling medium at the inlet of the fuel cell cooling pipeline exchanges heat with the cooling medium in the power battery cooling pipeline through the heat exchanger to keep the power battery warm and improve its low-temperature adaptability.

[0006] Currently, fuel cells generate electricity when starting up at low temperatures. The remaining electricity, after being used for vehicle consumption, is used to charge the power battery. However, the charging capacity of the power battery is relatively poor at the moment of fuel cell startup at low temperatures. Therefore, there is a great risk of damaging the power battery when fuel cells start up at low temperatures. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a fuel cell low-temperature start-up control method, control device, and readable storage medium, which minimizes damage to the power battery during low-temperature start-up.

[0008] A fuel cell low-temperature start-up control method, executed by the vehicle control unit (VCU), includes the following steps:

[0009] Step S1: Obtain the minimum power FCU_P of the fuel cell system in real time. fcs min Maximum permissible continuous charging power of the power battery (BMS_P) max chg Power battery heating film heating power BMS-P heat Real-time power VCU_P of the vehicle auxiliary system aux ;

[0010] Step S2: Determine FCU_P fcs min <BMS_P max chg +BMS_P heat +VCU_P aux -Whether δ1 is true or false, where δ1 is the design reserve power difference. If true, proceed to step S3; if false, proceed to step S4 and re-evaluate whether the above conditions are true or false, until FCU_P is satisfied. fcs min <BMS_P max chg +BMS_P heat +VCU_P aux After -δ1, proceed to step S5;

[0011] Step S3: Send a fuel cell system start-up enable signal to the FCU and a power battery thermal management electronic three-way valve opening enable signal to the BMS;

[0012] Step S4: Send a fuel cell non-start enable signal and a fuel cell PTC heater start enable signal to the FCU, and send a power battery thermal management electronic three-way valve open enable signal to the BMS;

[0013] Step S5: Send a fuel cell system start-up enable signal to the FCU.

[0014] Preferably, the start-up enable value VCU_P in the fuel cell system start-up enable signal in steps S3 and S5 is... fcs For VCU_P fcs =FCU_P fcs min .

[0015] Preferably, step S6 is also included:

[0016] When BMS_Temp_OUT≥BMS_Temp_SET is true, a battery thermal management electronic three-way valve closing enable signal is sent to the BMS, where BMS_Temp_OUT is the power battery outlet coolant temperature and BMS_Temp_SET is the preset power battery coolant control temperature.

[0017] Preferably, it also includes a step S7 set after step S6:

[0018] When FCU_Temp_OUT > FCU_Temp_SET is true, a fuel cell PTC heater shutdown enable signal is sent to the FCU, where FCU_Temp_OUT is the fuel cell outlet coolant temperature and FCU_Temp_SET is the preset fuel cell PTC heater shutdown temperature.

[0019] Preferably, the maximum permissible continuous charging power BMS_P of the power battery is obtained. max chg At that time, the maximum allowable continuous charging power (BMS_P) of the power battery is obtained by looking up the data table based on the battery temperature. max chg The data table contains the temperature of the power battery and the corresponding maximum allowable continuous charging power (BMS_P) for each temperature. max chg .

[0020] The present invention also discloses a fuel cell cryogenic start-up control device, including a memory and a processor; the memory is used to store a computer program; the processor is used to implement the fuel cell cryogenic start-up control method described in any of the above technical solutions when the computer program is executed.

[0021] The present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the fuel cell cryogenic start-up control method described in any of the above technical solutions.

[0022] In summary, the present invention has the following beneficial effects:

[0023] This invention, through pre-judgment, ensures that the fuel cell will not be started when the power battery is not allowed to be charged before the fuel cell is started at low temperatures, thereby protecting the power battery.

[0024] 2: In this invention, step S6 controls the temperature of the power battery to prevent performance degradation or even thermal runaway caused by excessively high battery temperature.

[0025] 3: In this invention, step S7 avoids damage to the fuel cell caused by excessively high temperature.

[0026] 4: In this invention, the maximum permissible continuous charging power BMS_P of the power battery is obtained. max chg At that time, the maximum allowable continuous charging power (BMS_P) of the power battery is obtained by looking up the data table based on the battery temperature. max chg The data collection is simple and convenient, which helps to shorten the data collection time and thus facilitates rapid startup.

[0027] 5: In this invention, a data judgment step is further provided between step S1 and step S2: if the minimum power of the battery system FCU_P fcs min When the value is 0, a fuel cell start-up enable signal is sent to the FCU, along with an alarm command; otherwise, step S2 is executed. This step prevents a situation where the condition in step S2 is met, but the power battery is not actually allowed to charge. Attached Figure Description

[0028] Figure 1 A flowchart for a low-temperature start-up control method for a hydrogen fuel cell vehicle.

[0029] Figure 2 This is a connection diagram between the fuel cell management system and the power battery management system.

[0030] Figure 3 This is a connection diagram for a hydrogen fuel cell vehicle.

[0031] Figure 4 This is another flowchart for a low-temperature start-up control method. Detailed Implementation

[0032] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings to further illustrate the technical solutions of the present invention. However, the present invention is not limited to these embodiments.

[0033] Example 1: Existing hydrogen fuel cell vehicles, such as Figure 3 As shown, it includes a fuel cell system, a power battery, a power battery management system (BMS), a control system, and a vehicle auxiliary system. The control system includes a vehicle control unit (VCU).

[0034] A fuel cell system includes a fuel cell and a fuel cell management system. The fuel cell system communicates with the vehicle control unit (VCU) through the fuel cell controller (FCU), transmitting parameters such as the minimum power of the fuel cell system (FCU_P). fcs min That is, the power of the fuel cell is fed back to the vehicle controller (VCU), and the fuel cell management system can manage the battery temperature of the fuel cell.

[0035] The power battery management system (BMS) is connected to the vehicle control unit (VCU) for communication. It can feed back some performance parameters of the power battery, such as the maximum allowable continuous charging power of the power battery, to the vehicle control unit (VCU). At the same time, it can also manage the battery temperature of the power battery itself through the instructions issued by the vehicle control unit (VCU).

[0036] See Figure 2 The diagram shows the connection between the fuel cell management system and the power battery management system. The fuel cell management system includes a fuel cell cooling pipe 11. The fuel cell coolant in the fuel cell cooling pipe 11 can absorb and dissipate heat to prevent the fuel cell 3 from overheating. The fuel cell cooling pipe 11 is equipped with a fuel cell water pump 1, a fuel cell outlet temperature sensor 2, a fuel cell thermal management three-way valve 8, a fuel cell PTC heater 9, and a fuel cell thermal management electronic three-way valve 10. The fuel cell PTC heater 9 is used to connect to the power battery and is powered by the power battery. The other outlet of the fuel cell thermal management three-way valve 8 and the other outlet of the fuel cell thermal management electronic three-way valve 10 are used to connect to a radiator.

[0037] The power battery management system includes a power battery cooling pipe 12 connected to the fuel cell cooling pipe 11 via a battery thermal management three-way valve 4 and a power battery thermal management electronic three-way valve 7. The power battery cooling pipe 12 contains power battery coolant. A battery thermal management heat exchanger outlet temperature sensor 5 and a battery thermal management heat exchanger 6 are installed on the power battery cooling pipe 12. After the battery thermal management three-way valve 4 and the power battery thermal management electronic three-way valve 7 switch channels, the fuel cell cooling pipe 11 and the power battery cooling pipe 12 are connected, thereby realizing heat exchange between the fuel cell coolant and the power battery coolant, and achieving control of the battery temperature of the power battery.

[0038] The vehicle auxiliary system is connected to the vehicle controller (VCU) for communication.

[0039] Based on existing hydrogen fuel cell vehicles, this invention proposes a novel low-temperature start-up control method for hydrogen fuel cell vehicles, executed by the vehicle control unit (VCU), such as... Figure 1 As shown, it includes the following steps:

[0040] Step S1: Obtain the minimum power FCU_P of the fuel cell system in real time. fcs min Maximum permissible continuous charging power of the power battery (BMS_P) max chg Power battery heating film heating power BMS_P heat (This refers to the power generated by the battery itself, not the power transferred through heating the coolant), the real-time power VCU_P of the vehicle's auxiliary systems. aux (The vehicle's auxiliary systems include the car's inherent air pump, steering pump, air conditioning, heating, and other systems.)

[0041] Step S2: Determine FCU_P fcs min <BMS_P max chg +BMS_P heat +VCU_P aux -Whether δ1 holds true, where δ1 is the design reserve power difference;

[0042] If true, it means that if fuel cell 3 is turned on at minimum power generation, the amount of charge from fuel cell 3 to power battery is controlled within the maximum allowable charging range of power battery. Therefore, power battery can be charged at present and will not be damaged during charging. At this time, step S3 is executed. Step S3 includes: ① The vehicle controller VCU sends a fuel cell system start-up enable signal to the FCU, so that the FCU controls the fuel cell 3 to start at low temperature; ② The vehicle controller VCU sends a power battery thermal management electronic three-way valve 7 opening enable signal to the BMS, so that the fuel cell cooling pipe 11 is connected to the power battery cooling pipe, thereby allowing the fuel cell coolant that has heated up after the fuel cell 3 is turned on to transfer heat to the power battery coolant, thereby heating the power battery and improving the charging performance of the power battery.

[0043] If this condition is not met, it means that even if fuel cell 3 is turned on at minimum power output, its charging capacity to the power battery still exceeds the maximum allowable charging range of the power battery. Therefore, the power battery is currently not allowed to be charged. In this case, step S4 is executed. Step S4 includes: ① The vehicle controller (VCU) sends a fuel cell non-start enable signal to the fuel cell controller (FCU), preventing the FCU from controlling the start of the fuel cell and thus protecting the power battery; ② The VCU sends a fuel cell PTC heater start enable signal to the FCU, causing the fuel cell PTC heater 9 to start. When the fuel cell PTC heater 9 starts, it draws power from the power battery, which increases the effective discharge current of the power battery, thereby promoting the heating of the power battery and increasing the maximum allowable continuous charging power (BMS_P) of the power battery. max chg This refers to the temperature of the power battery and the maximum allowable continuous charging power (BMS_P) at each temperature. max chg The data is pre-stored in the register as a data table. The vehicle control unit (VCU) looks up the data table based on the battery temperature to obtain the real-time maximum allowable continuous charging power of the battery, BMS_P. max chgData collection is simple and convenient, which helps to shorten the data collection time. On the other hand, when the fuel cell PTC heater 9 is started, it heats the coolant in the fuel cell cooling pipe 11, causing the fuel cell coolant to rise in temperature. ③ The vehicle controller VCU sends an enable signal to the power battery thermal management electronic three-way valve 7 to the BMS, so that the fuel cell cooling pipe 11 is connected to the power battery cooling pipe, thereby allowing the fuel cell coolant, which has risen in temperature due to the start of the fuel cell PTC heater 9, to transfer heat to the power battery coolant, thereby heating the power battery and further improving the charging performance of the power battery.

[0044] After step S4, FCU_P needs to be re-evaluated. fcs min <BMS-P max chg +BMS-P heat +VCU_P aux Whether -δ1 holds true until FCU_P is satisfied. fcs min <BMS_P max chg +BMS_P heat +VCU_P aux -δ1 and then execute step S5; Step S5: Send a fuel cell system start-up enable signal to the FCU to enable the FCU to control the start of fuel cell 3.

[0045] As can be seen, this method, before the fuel cell starts at low temperatures, pre-judgments to ensure that the fuel cell does not start when the power battery is not allowed to charge, thereby protecting the power battery. When the start-up conditions are not met, it sends a fuel cell PTC heater start-up enable signal to the FCU and a power battery thermal management electronic three-way valve open-up enable signal to the BMS to improve the charging performance of the power battery and achieve the fastest possible start-up of the fuel cell.

[0046] In step S3, the startup enable value VCU_P in the startup enable signal fcs For VCU_P fcs =FCU_P fcs min This means starting the fuel cell with minimum power to achieve the fastest possible startup. Similarly, in step S5, the startup enable value VCU-P in the startup enable signal... fcs Also for VCU_P fcs =FCU_P fcs min .

[0047] After the fuel cell starts up at low temperatures, the temperature of the power battery will gradually rise. It is necessary to consider controlling the temperature of the power battery to avoid performance degradation or even thermal runaway caused by excessively high battery temperature. Therefore, the method in this invention also includes step S6:

[0048] When BMS_Temp_OUT ≥ BMS_Temp_SET, a battery thermal management electronic three-way valve closing enable signal is sent to the BMS. Here, BMS_Temp_OUT is the power battery outlet coolant temperature, one of the real-time feedback signals from the power battery management system (BMS) to the vehicle control unit (VCU), and BMS_Temp_SET is the preset power battery coolant control temperature. Step S6 is set after steps S3 and S5.

[0049] The method of this invention further includes a step S7 set after step S6:

[0050] When FCU_Temp_OUT > FCU_Temp_SET, a fuel cell PTC heater shutdown enable signal is sent to the FCU. Here, FCU_Temp_OUT is the fuel cell outlet coolant temperature, one of the real-time feedback signals from the fuel cell controller (FCU) to the vehicle controller (VCU), and FCU_Temp_SET is the preset fuel cell PTC heater shutdown temperature. This method prevents damage to the fuel cell due to excessively high temperatures.

[0051] Example 2: In low-temperature environments, especially below -10 to -20 degrees Celsius, data transmission devices such as data cables and wireless modules may become icy or damaged, leading to data acquisition failure. This occurs when the fuel cell system's minimum power (FCU-P) is reached. fcs min When the value is 0, if the judgment condition in step S2 is executed directly, a situation may occur where the judgment condition is met but the power battery is not actually allowed to charge. Therefore, this embodiment differs from embodiment 1, as follows: Figure 4 As shown, a data judgment step is also set between step S1 and step S2: if the minimum power of the battery system FCU-P fcs min When the value is 0, a fuel cell start-up enable signal is sent to the FCU, along with an alarm command; otherwise, step S2 is executed. This step effectively avoids the aforementioned situation.

[0052] Example 3 relates to a fuel cell cryogenic start-up control device, including a memory and a processor; the memory is used to store a computer program; the processor is used to implement the fuel cell cryogenic start-up control method as described in Example 1 when the computer program is executed.

[0053] Example 4 relates to a computer-readable storage medium storing a computer program that, when executed by a processor, implements the fuel cell cryogenic start-up control method as described in Example 1.

[0054] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the concept and scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the design concept of the present invention should fall within the protection scope of the present invention. All technical contents for which protection is sought in this invention have been fully described in the claims.

Claims

1. A method for controlling the low-temperature start-up of a fuel cell, applied to a hydrogen fuel cell vehicle, the hydrogen fuel cell vehicle comprising a fuel cell management system and a power battery management system; The fuel cell management system includes a fuel cell cooling pipe (11), on which a fuel cell water pump (1), a fuel cell outlet temperature sensor (2), a fuel cell thermal management tee (8), a fuel cell PTC heater (9), and a fuel cell thermal management electronic tee valve (10) are installed. The fuel cell PTC heater (9) is used to connect to the power battery, and one outlet of the fuel cell thermal management tee (8) and one outlet of the fuel cell thermal management electronic tee valve (10) are used to connect to the radiator. The power battery management system includes a power battery cooling pipe (12) connected to the fuel cell cooling pipe (11) via a battery thermal management three-way valve (4) and a power battery thermal management electronic three-way valve (7). The power battery cooling pipe (12) contains power battery coolant. A battery thermal management heat exchanger outlet temperature sensor (5) and a battery thermal management heat exchanger (6) are installed on the power battery cooling pipe (12). After the battery thermal management three-way valve (4) and the power battery thermal management electronic three-way valve (7) switch channels, the fuel cell cooling pipe (11) and the power battery cooling pipe (12) are connected, thereby realizing the heat exchange between the fuel cell coolant and the power battery coolant. Its features are, Includes the following steps: Step S1: Obtain the minimum power of the fuel cell system in real time Maximum permissible continuous charging power of the power battery Heating power of power battery heating film Real-time power of vehicle auxiliary systems ; Step S2: Determine Whether it is true or not, among which, To allow for a power difference in the design, if the condition is met, proceed to step S3; if not, proceed to step S4 and re-evaluate the condition until it is satisfied. Then, proceed to step S5; Step S3: Send a fuel cell system start-up enable signal to the fuel cell controller FCU and a power battery thermal management electronic three-way valve opening enable signal to the power battery management system BMS, so that the fuel cell cooling pipe (11) and the power battery cooling pipe (12) are connected, thereby allowing the fuel cell coolant that has heated up after the fuel cell (3) starts to transfer heat to the power battery coolant, thereby heating the power battery. Step S4: Send a fuel cell non-start enable signal and a fuel cell PTC heater start enable signal to the FCU and a power battery thermal management electronic three-way valve open enable signal to the BMS, so that the fuel cell cooling pipe (11) and the power battery cooling pipe (12) are connected, thereby allowing the fuel cell coolant heated by the start of the fuel cell PTC heater (9) to transfer heat to the power battery coolant, thereby heating the power battery. Step S5: Send a fuel cell system start-up enable signal to the FCU.

2. The fuel cell cryogenic start-up control method according to claim 1, characterized in that, The start-up enable value in the fuel cell system start-up enable signal in steps S3 and S5 for .

3. The fuel cell cryogenic start-up control method according to claim 1, characterized in that, It also includes step S6: when Upon establishment, a power battery thermal management electronic three-way valve closing enable signal is sent to the BMS, wherein... This refers to the outlet coolant temperature of the power battery. The preset temperature is set for the power battery coolant.

4. The fuel cell cryogenic start-up control method according to claim 3, characterized in that, It also includes setting step S7 after step S6: when Upon establishment, a fuel cell PTC heater shutdown enable signal is sent to the FCU, wherein, This refers to the outlet coolant temperature of the fuel cell. This is the preset shut-off temperature for the fuel cell PTC heater.

5. The fuel cell cryogenic start-up control method according to claim 1, characterized in that, In step S1, the maximum allowable continuous charging power of the power battery is obtained. At that time, the maximum allowable continuous charging power of the power battery is obtained by looking up the data table based on the temperature of the power battery. The data table contains the temperature of the power battery and the maximum allowable continuous charging power of the power battery at each temperature. .

6. The fuel cell cryogenic start-up control method according to claim 1, characterized in that, A data judgment step is also set between step S1 and step S2: if the fuel cell system has the minimum power When the value is 0, a fuel cell start-up enable signal is sent to the FCU, and an alarm command is sent; otherwise, step S2 is executed.

7. A fuel cell cryogenic start-up control device, characterized in that, It includes a memory and a processor; the memory is used to store a computer program; the processor is used to implement the fuel cell cryogenic start-up control method as described in any one of claims 1-6 when the computer program is executed.

8. A computer-readable storage medium, characterized in that, The storage medium stores a computer program that, when executed by a processor, implements the fuel cell cryogenic start-up control method as described in any one of claims 1-6.

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