A fuel cell cold start system

Abstract

The application discloses a fuel cell cold starting system, comprising: a stack body, a main cooling liquid flow path, an auxiliary cooling liquid flow path and a main control module, the main cooling liquid flow path flows through a first electrically controlled three-way valve, a main radiator and a heater, the input end of the first electrically controlled three-way valve is connected with the inlet end of the main cooling liquid flow path, the first output end is connected with the main radiator, and the second output end is connected with the heater; the auxiliary cooling liquid flow path sequentially flows through an auxiliary radiator, an air compressor controller and an air compressor, the auxiliary cooling liquid flow path is provided with a bypass branch parallel to the auxiliary radiator, and the input end of the auxiliary radiator and the inlet end of the bypass branch are provided with a conduction control component; and the main control module is used for changing the conduction state of the first electrically controlled three-way valve and the conduction control component according to a first temperature sensor and a second temperature sensor. The application can improve the cold starting speed of the system.

Description

Technical Field

[0001] This application relates to the field of fuel cell technology, and in particular to a fuel cell cold start system. Background Technology

[0002] With the scarcity of traditional energy sources such as fossil fuels and the ongoing global warming, humanity faces a massive energy and survival crisis. There is an urgent need to find new, efficient, and clean energy sources to gradually replace traditional energy sources in order to address this crisis. Fuel cells, with their superior performance, have become a research hotspot in countries worldwide, playing a significant role in power generation, mobile power supplies, and on-board power. Research on fuel cell vehicles is progressing rapidly, but their commercialization still faces technological bottlenecks. Besides battery durability and cost factors, improving low-temperature start-up performance is also a key issue.

[0003] When the temperature inside a fuel cell drops below freezing, the water produced during fuel cell operation will freeze. If the water in the catalyst layer freezes before the temperature inside the cell rises to zero degrees Celsius, the electrochemical reaction will stop due to the freezing of the reaction area. Furthermore, the expansion of the ice during formation can severely damage the structure of the membrane electrode assembly. Currently, auxiliary heating is typically used to address the cold start problem, most commonly through PTC (Positive Temperature Coefficient) water heaters. However, current PTC water heaters have limited heating power; in 20–200 kW systems, 6 kW or 8 kW PTC water heaters are typically used. Higher power water heaters are larger, and due to technological and system space limitations, it is difficult to improve the cold start speed using high-power PTC water heaters. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a fuel cell cold start system that can improve the cold start speed of the system.

[0005] This application provides a fuel cell cold start system, including: The fuel cell stack body includes a coolant inlet and a coolant outlet; A main coolant flow path is provided, with a first temperature sensor at the outlet end of the main coolant flow path and connected to the coolant inlet. A second temperature sensor at the inlet end of the main coolant flow path is also provided and connected to the coolant outlet. The main coolant flow path passes through a first electrically controlled three-way valve, a main radiator, and a heater. The input end of the first electrically controlled three-way valve is connected to the inlet end of the main coolant flow path. The first output end of the first electrically controlled three-way valve is connected to the input end of the main radiator. The second output end of the first electrically controlled three-way valve is connected to the input end of the heater. The output end of the main radiator is connected to the output end of the heater and to the outlet end of the main coolant flow path. A coolant auxiliary flow path is provided, wherein the inlet end of the coolant auxiliary flow path is connected to the pipeline between the heater and the outlet end of the main coolant flow path, and the outlet end of the coolant auxiliary flow path is connected to the pipeline between the first electrically controlled three-way valve and the inlet end of the main coolant flow path. The coolant auxiliary flow path flows sequentially through the auxiliary radiator, the air compressor controller and the air compressor. The coolant auxiliary flow path is also provided with a bypass branch connected in parallel with the auxiliary radiator. Conduction control components are provided at the input end of the auxiliary radiator and the inlet end of the bypass branch. The main control module is used to change the conduction state of the first electrically controlled three-way valve and the conduction control component based on the temperature values ​​detected by the first temperature sensor and the second temperature sensor.

[0006] The fuel cell cold start system according to the embodiments of this application has at least the following beneficial effects: the temperature of the coolant entering the fuel cell stack body and the temperature of the coolant flowing out of the fuel cell stack body can be obtained based on the temperature values ​​detected by the first temperature sensor and the second temperature sensor. When the temperature inside the fuel cell stack body is lower than the freezing point, the water generated by the operation of the fuel cell stack body will freeze. At this time, a cold start needs to be performed in advance before the fuel cell stack body starts working, that is, the temperature of the coolant needs to be raised in advance. In the main coolant flow path, the heater can be activated to heat the flowing coolant, thereby rapidly increasing the coolant temperature entering the fuel cell stack. Simultaneously, the first electrically controlled three-way valve can be controlled to ensure that most or all of the coolant in the main flow path flows through the heater. On the other hand, in the auxiliary coolant flow path, to further increase the coolant temperature, the conduction control component controls the flow of most or all of the coolant through the bypass branch, preventing the coolant temperature from dropping again after passing through the auxiliary radiator. The air compressor controller and air compressor generate a significant amount of heat during operation, especially the air compressor. The coolant flowing from the bypass branch carries away the heat generated by these electronic components after passing through the air compressor controller and air compressor, thus increasing the coolant temperature. Through the combined action of the main coolant flow path and the auxiliary coolant flow path, the coolant temperature rise is accelerated, thereby improving the cold start speed of the fuel cell system.

[0007] According to some embodiments of this application, the conduction control component is a second electrically controlled three-way valve. The input end of the second electrically controlled three-way valve is connected to the pipeline between the heater and the outlet end of the main coolant flow path. The first output end of the second electrically controlled three-way valve is connected to the input end of the auxiliary radiator, and the second output end of the second electrically controlled three-way valve is connected to the inlet end of the bypass branch. The main control module is specifically used to: when the temperature value detected by the second temperature sensor is less than a preset first temperature threshold, open the heater and adjust the opening degree of the first electrically controlled three-way valve and the second electrically controlled three-way valve so that the coolant in the main coolant flow path only flows through the branch with the heater, and the coolant in the auxiliary coolant flow path only flows through the bypass branch.

[0008] According to some embodiments of this application, the coolant auxiliary flow path is provided with a third temperature sensor at the pipeline after the auxiliary radiator and the bypass branch and before the air compressor. The main control module is further configured to: when the temperature value detected by the first temperature sensor is greater than or equal to a preset second temperature threshold, adjust the opening of the second electrically controlled three-way valve so that the coolant in the coolant auxiliary flow path only flows through the branch where the auxiliary radiator is located; when the temperature value detected by the third temperature sensor is greater than or equal to a preset third temperature threshold, turn on the cooling fan of the auxiliary radiator and control the speed of the cooling fan of the auxiliary radiator so that the temperature value detected by the third temperature sensor reaches a preset first target temperature value; wherein, the third temperature threshold is greater than or equal to the second temperature threshold; when the first temperature sensor... When the temperature value detected by the sensor is greater than or equal to a preset fourth temperature threshold, the heater is turned off, and the opening of the first electrically controlled three-way valve is adjusted so that the coolant in the main coolant flow path flows simultaneously through the branch with the heater and the branch with the main radiator; wherein, the fourth temperature threshold is greater than or equal to the second temperature threshold; when the temperature value detected by the first temperature sensor is greater than or equal to a preset fifth temperature threshold, the cooling fan of the main radiator is turned on and the speed of the cooling fan of the auxiliary radiator is controlled so that the temperature value detected by the first temperature sensor reaches a preset second target temperature value, and the opening of the first electrically controlled three-way valve is adjusted so that the coolant in the main coolant flow path flows only through the branch with the main radiator; wherein, the fifth temperature threshold is greater than or equal to the fourth temperature threshold.

[0009] According to some embodiments of this application, the conduction control component is a solenoid valve, which is disposed on the bypass branch; the main control module is specifically used to: when the temperature value detected by the second temperature sensor is less than a preset first temperature threshold, open the heater, adjust the opening of the first electrically controlled three-way valve, and control the solenoid valve to open, so that the coolant in the main coolant flow path flows only through the branch with the heater, and the coolant in the auxiliary coolant flow path flows only through the bypass branch; when the temperature value detected by the first temperature sensor is greater than a preset second temperature threshold, control the solenoid valve to close, so that the coolant in the auxiliary coolant flow path flows only through the branch with the auxiliary radiator.

[0010] According to some embodiments of this application, the coolant auxiliary flow path is further provided with a hydrogen pump controller and a booster module. The hydrogen pump controller and the booster module are located after the auxiliary radiator and the bypass branch, and the pipeline corresponding to the hydrogen pump controller, the pipeline corresponding to the booster module, and the pipeline corresponding to the air compressor controller and the air compressor are connected in parallel.

[0011] According to some embodiments of this application, the fuel cell stack body further includes an air inlet and an air outlet; the fuel cell cold start system further includes an air intake path and an air outlet path; the inlet end of the air intake path is used to allow external air to enter, the air in the air intake path flows through the air compressor, the air intake path is divided into an air purging branch and an air intake branch after the air compressor, the air purging branch is provided with a first back pressure valve, the outlet end of the air purging branch is connected to the outer shell of the fuel cell stack body, the outlet end of the air intake branch is connected to the air inlet, and the air intake branch is provided with a second back pressure valve; the inlet end of the air outlet path is connected to the air outlet; the main control module is also used to change the conduction state of the first back pressure valve and the second back pressure valve according to the temperature values ​​detected by the first temperature sensor and the second temperature sensor.

[0012] According to some embodiments of this application, a third back pressure valve is provided in the air outlet flow path, and an exhaust branch connected to the front of the third back pressure valve is provided on the rear side of the output end of the first back pressure valve in the air purging branch, and a ball valve is provided on the exhaust branch; the main control module is specifically used to: when the temperature value detected by the second temperature sensor is less than a preset first temperature threshold, control the opening degree of the first back pressure valve to 50%, completely close the second back pressure valve and completely open the third back pressure valve, and adjust the opening degree of the ball valve so that part of the air in the inlet end of the air inlet flow path is purged to the outer shell of the fuel cell body; wait for a preset first time, and control the air compressor to operate.

[0013] According to some embodiments of this application, the air intake flow path is provided with an intercooler on the rear side of the output end of the air compressor. The intercooler is also provided with a coolant branch. The inlet end of the coolant branch is connected to the pipeline between the heater and the outlet end of the main coolant flow path. The outlet end of the coolant branch is connected to the pipeline between the first electrically controlled three-way valve and the inlet end of the main coolant flow path. The coolant in the coolant branch is used to exchange heat for the gas in the air intake flow path.

[0014] According to some embodiments of this application, the fuel cell stack body further includes a hydrogen inlet and a hydrogen outlet; the fuel cell cold start system further includes a hydrogen flow path, the first inlet end of the hydrogen flow path is connected to an external hydrogen supply device, the second inlet end of the hydrogen flow path is connected to the hydrogen outlet, and the outlet end of the hydrogen flow path is connected to the hydrogen inlet. Gas received at the first inlet end of the hydrogen flow path flows sequentially through a hydrogen filter, a shut-off valve, and a proportional valve to the outlet end of the hydrogen flow path. Gas received at the second inlet end of the hydrogen flow path flows sequentially through a gas-liquid separator and a circulation pump to the outlet end of the hydrogen flow path. The output end of the circulating pump is connected to the output end of the proportional valve, and the drain port of the gas-liquid separator is connected to the output end of the third back pressure valve through a drain valve. The main control module is also used to: control the operating state of the air compressor, open the shut-off valve, the proportional valve and the circulating pump, and control the conduction state of the drain valve when the temperature value detected by the second temperature sensor is greater than the preset sixth temperature threshold, so as to adjust the gas pressure at the hydrogen inlet; and adjust the first back pressure valve, the second back pressure valve and the third back pressure valve to adjust the air flow rate at the inlet end of the air intake flow path and the gas pressure at the air inlet.

[0015] According to some embodiments of this application, the main control module is further configured to: reduce the opening of the first back pressure valve when the temperature detected by the first temperature sensor is greater than a preset seventh temperature threshold, control the second back pressure valve to be fully opened, adjust the opening of the third back pressure valve and the speed of the air compressor, so that the air flow rate at the inlet end of the air intake path and the air pressure at the air inlet reach the standard of the working idle speed point of the fuel cell stack.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] Additional aspects and advantages of this application will become apparent and readily understood in conjunction with the following description of the embodiments, in which: Figure 1 This is a schematic diagram of the structure of a fuel cell cold start system according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a fuel cell cold start system according to another embodiment of this application.

[0018] The attached icons are numbered as follows: The fuel cell stack body is 100; the coolant inlet is 110; the coolant outlet is 120; the air inlet is 130; the air outlet is 140; the hydrogen inlet is 150; and the hydrogen outlet is 160. Coolant main flow path 200; First temperature sensor 210; Second temperature sensor 220; First electronically controlled three-way valve 230; Main radiator 240; Heater 250; Expansion tank 261; Water pump 262; Particulate filter 263; Deionizer 264; First pressure sensor 270; Coolant auxiliary flow path 300; auxiliary radiator 310; bypass branch 320; second electrically controlled three-way valve 331; solenoid valve 332; air compressor controller 341; air compressor 342; hydrogen pump controller 350; booster module 360; third temperature sensor 370; Air intake path 400; air purging branch 410; first back pressure valve 411; exhaust branch 412; ball valve 413; second flow meter 414; fourth pressure sensor 415; air intake branch 420; second back pressure valve 421; intercooler 430; air filter 440; first flow meter 450; humidifier 460; Air outlet flow path 500; third back pressure valve 510; mixing chamber 520; silencer 530; Hydrogen flow path 600; hydrogen filter 610; shut-off valve 620; proportional valve 630; gas-liquid separator 640; circulating pump 650; drain valve 660; second pressure sensor 670; third pressure sensor 680. Detailed Implementation

[0019] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0020] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0021] In the description of this application, the use of "first" and "second" is for the purpose of distinguishing technical features only, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0022] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0023] With the scarcity of traditional energy sources such as fossil fuels and the ongoing global warming, humanity faces a massive energy and survival crisis. There is an urgent need to find new, efficient, and clean energy sources to gradually replace traditional energy sources and address this crisis. Fuel cells, with their superior performance, have become a research hotspot in countries worldwide, playing a significant role in power generation, mobile power, and vehicle power. Research on fuel cell vehicles is progressing rapidly, but their commercialization still faces technological bottlenecks. Besides battery durability and cost factors, improving low-temperature start-up performance is also a key issue. When the temperature inside the fuel cell drops below freezing, the water produced during fuel cell operation freezes. If the water in the catalyst layer freezes before the internal temperature rises to zero degrees Celsius, the electrochemical reaction will stop due to the ice covering the reaction area. Furthermore, the expansion of ice formation can severely damage the structure of the membrane electrode assembly. Currently, auxiliary heating is typically used to address the cold start problem, most commonly through a PTC water heater. Due to the limited heating power of current PTC water heaters, 6kW or 8kW PTC water heaters are usually used in 20-200kW systems. However, the larger the power of the water heater, the larger the volume. Due to technical and system space limitations, it is difficult to improve the cold start speed by using high-power PTC water heaters.

[0024] Based on this, this application provides a fuel cell cold start system to solve the aforementioned technical problems. The technical solution provided by this application will be described in detail below.

[0025] Reference Figure 1 and Figure 2This application provides a fuel cell cold start system, including a fuel cell stack body 100, a main coolant flow path, a main coolant flow path 300, and a main control module. Specifically, the fuel cell stack body 100 includes a coolant inlet 110 and a coolant outlet 120. A first temperature sensor 210 is provided at the outlet end of the main coolant flow path and is connected to the coolant inlet 110. A second temperature sensor 220 is provided at the inlet end of the main coolant flow path and is connected to the coolant outlet 120. The main coolant flow path passes through a first electrically controlled three-way valve 230, a main radiator 240, and a heater 250. The input end of the first electrically controlled three-way valve 230 is connected to the inlet end of the main coolant flow path. The first output end of the first electrically controlled three-way valve 230 is connected to the input end of the main radiator 240, and the second output end of the first electrically controlled three-way valve 230 is connected to the input end of the heater 250. The main radiator 240... The output terminal of the 0 is connected to the output terminal of the heater 250 and the outlet terminal of the main coolant flow path; the inlet terminal of the coolant auxiliary flow path 300 is connected to the pipeline between the heater 250 and the outlet terminal of the main coolant flow path, and the outlet terminal of the coolant auxiliary flow path 300 is connected to the pipeline between the first electrically controlled three-way valve 230 and the inlet terminal of the main coolant flow path. The coolant auxiliary flow path 300 flows sequentially through the auxiliary radiator 310, the air compressor controller 341, and the air compressor 342. The coolant auxiliary flow path 300 is also provided with a bypass branch 320 connected in parallel with the auxiliary radiator 310. A conduction control component is provided at the input terminal of the auxiliary radiator 310 and the inlet terminal of the bypass branch 320. The main control module is used to change the conduction state of the first electrically controlled three-way valve 230 and the conduction control component according to the temperature values ​​detected by the first temperature sensor 210 and the second temperature sensor 220. Among them, the heater 250 can be a PTC heater 250.

[0026] Based on the temperature values ​​detected by the first temperature sensor 210 and the second temperature sensor 220, the temperature at which the coolant enters the fuel cell stack 100 and the temperature at which it flows out of the fuel cell stack 100 can be obtained. When the temperature inside the fuel cell stack 100 is lower than the freezing point, the water generated by the operation of the fuel cell stack 100 will freeze. At this time, a cold start needs to be performed in advance before the fuel cell stack 100 starts working, that is, the temperature of the coolant needs to be raised in advance. In the main coolant flow path, the heater 250 can be activated to heat the flowing coolant, thereby rapidly increasing the temperature of the coolant entering the fuel cell stack 100. Simultaneously, the first electrically controlled three-way valve 230 can be controlled to ensure that most or all of the coolant in the main coolant flow path flows through the heater 250. On the other hand, in the auxiliary coolant flow path 300, to increase the coolant temperature, the conduction control component controls most or all of the coolant to flow through the bypass branch 320, preventing the coolant temperature from dropping again after passing through the auxiliary radiator 310. The air compressor controller 341 and air compressor 342 generate a large amount of heat during operation, especially the air compressor 342. The coolant flowing from the bypass branch 320 carries away the heat generated by the electronic components after passing through the air compressor controller 341 and air compressor 342, thus increasing the coolant temperature. Through the combined action of the main coolant flow path and the auxiliary coolant flow path 300, the increase in coolant temperature is accelerated, significantly improving the cold start speed of the fuel cell system.

[0027] Furthermore, refer to Figure 1 The main coolant flow path is followed by a water pump 262 and a particulate filter 263 after the output of the main radiator 240 and heater 250. The input of the water pump 262 is connected to the water supply end of the expansion tank 261. A first pressure sensor 270 is also provided next to the first temperature sensor 210.

[0028] Reference Figure 1It is understood that the conduction control component is the second electrically controlled three-way valve 331. The input end of the second electrically controlled three-way valve 331 is connected to the pipeline between the heater 250 and the outlet end of the main coolant flow path. The first output end of the second electrically controlled three-way valve 331 is connected to the input end of the auxiliary radiator 310, and the second output end of the second electrically controlled three-way valve 331 is connected to the inlet end of the bypass branch 320. The main control module is specifically used to: when the temperature value detected by the second temperature sensor 220 is less than or equal to the preset first temperature threshold, open the heater 250 and adjust the opening degree of the first electrically controlled three-way valve 230 and the second electrically controlled three-way valve 331 so that the coolant in the main coolant flow path only flows through the branch with the heater 250, and the coolant in the auxiliary coolant flow path 300 only flows through the bypass branch 320. The main control module can control the opening degree of the first electrically controlled three-way valve 230 to control the amount of coolant flowing through the heater 250 and the main radiator 240 in the main coolant flow path. Simultaneously, it can control the opening degree of the second electrically controlled three-way valve 331 to control the amount of coolant flowing through the auxiliary radiator 310 and the bypass branch 320 in the auxiliary coolant flow path 300. In this embodiment, the first temperature threshold is 0 degrees Celsius. Specifically, before executing the steps of this application, the ambient temperature around the fuel cell system can be detected. When the ambient temperature is below 0°C, the first and second electrically controlled three-way valves are adjusted to 50% opening. After 5 seconds, the water pump 262 is turned on and runs for 5 seconds. The temperature value detected by the second temperature sensor 220 is used to obtain the desired temperature. If the coolant outlet temperature is detected to be ≤0℃, the cold start procedure is initiated. The opening of the first electric three-way valve and the second electric three-way valve 2 is set to 0%, and the PTC water heater 250 is turned on. This ensures that the coolant in the main coolant flow path flows only through the branch equipped with heater 250, and the coolant in the auxiliary coolant flow path 300 flows only through the bypass branch 320. By activating heater 250 to heat the flowing coolant, and by the coolant flowing out of bypass branch 320 passing through air compressor controller 341 and air compressor 342, the heat generated by the electronic device during operation is carried away. Through the combined action of the main coolant flow path and the auxiliary coolant flow path 300, the coolant temperature can be increased more quickly, thereby improving the cold start speed of the fuel cell system.

[0029] Continue to refer to Figure 1It is understandable that the coolant auxiliary flow path 300 is equipped with a third temperature sensor 370 after the auxiliary radiator 310 and the bypass branch 320 and before the air compressor 342. The main control module is also used to: when the temperature value detected by the first temperature sensor 210 is greater than or equal to a preset second temperature threshold, adjust the opening of the second electrically controlled three-way valve 331 so that the coolant in the coolant auxiliary flow path 300 only flows through the branch equipped with the auxiliary radiator 310; when the temperature value detected by the third temperature sensor 370 is greater than or equal to a preset third temperature threshold, turn on the cooling fan of the auxiliary radiator 310 and control the speed of the cooling fan of the auxiliary radiator 310 so that the temperature value detected by the third temperature sensor 370 reaches a preset first target temperature value; wherein, the third temperature threshold is greater than or equal to the second temperature threshold; when the first temperature threshold is greater than or equal to the second temperature threshold, adjust the opening of the second electrically controlled three-way valve 331 so that the coolant in the coolant auxiliary flow path 300 only flows through the branch equipped with the auxiliary radiator 310; when the temperature value detected by the third temperature sensor 370 ... When the temperature value detected by the first temperature sensor 210 is greater than or equal to a preset fourth temperature threshold, the heater 250 is turned off, and the opening of the first electrically controlled three-way valve 230 is adjusted so that the coolant in the main coolant flow path flows simultaneously through the branch with the heater 250 and the branch with the main radiator 240; wherein, the fourth temperature threshold is greater than or equal to the second temperature threshold; when the temperature value detected by the first temperature sensor 210 is greater than or equal to a preset fifth temperature threshold, the cooling fan of the main radiator 240 is turned on and the speed of the cooling fan of the auxiliary radiator 310 is controlled so that the temperature value detected by the first temperature sensor 210 reaches the preset second target temperature value, and the opening of the first electrically controlled three-way valve 230 is adjusted so that the coolant in the main coolant flow path flows only through the branch with the main radiator 240; wherein, the fifth temperature threshold is greater than or equal to the fourth temperature threshold.

[0030] In the embodiments of this application, the second temperature threshold is set to 58°C, the third and fourth temperature thresholds are both set to 60°C, the fifth temperature threshold is 65°C, the first target temperature is 50°C, and the second target temperature is 70°C. Specifically, when the coolant inlet temperature detected by the first temperature sensor 210 is ≥58°C, the opening of the second electronically controlled three-way valve 331 is adjusted to 100% (i.e., all the coolant in the coolant auxiliary flow path 300 flows through the auxiliary radiator 310). When the temperature detected by the third temperature sensor 370 is ≥60°C, the auxiliary fan in the auxiliary radiator 310 is turned on. The auxiliary fan speed is adjusted using a PID (Proportional Integral Derivative) algorithm to control the temperature at 50°C, with 50°C as the target temperature. When the coolant inlet temperature detected by the first temperature sensor 210 is ≥60℃, the PTC water heater 250 is shut down (the heater 250 is only restarted when the temperature of the fuel cell stack body 100 is less than 40℃), and the first electrically controlled three-way valve 230 is slowly opened to a small opening degree (to prevent the temperature drop of the fuel cell inlet water from being less than 5℃). In addition, in the scheme where the temperature value detected by the first temperature sensor 210 is greater than or equal to a preset fifth temperature threshold, the cooling fan of the main radiator 240 is turned on and the speed of the cooling fan of the auxiliary radiator 310 is controlled, and the opening degree of the first electrically controlled three-way valve 230 is adjusted, more specifically, when the coolant inlet temperature is ≥65℃, the opening degree of the electrically controlled three-way valve 1 is slowly increased until the electrically controlled three-way valve 1 is fully open; when the coolant inlet temperature is ≥68℃, the main radiator 240 is turned on, and the fan speed of the main radiator 240 is adjusted using a PID algorithm with a target temperature of 70℃ to control the temperature at 70℃.

[0031] Reference Figure 2 It is understandable that the conduction control component is a solenoid valve 332, which is located on the bypass branch 320. The main control module is specifically used to: when the temperature value detected by the second temperature sensor 220 is less than a preset first temperature threshold, open the heater 250, adjust the opening of the first electrically controlled three-way valve 230, and control the solenoid valve 332 to open, so that the coolant in the main coolant flow path only flows through the branch with the heater 250, and the coolant in the coolant auxiliary flow path 300 only flows through the bypass branch 320; when the temperature value detected by the first temperature sensor 210 is greater than a preset second temperature threshold, control the solenoid valve 332 to close, so that the coolant in the coolant auxiliary flow path 300 only flows through the branch with the auxiliary radiator 310. If, to reduce costs, the more expensive electrically controlled three-way valve is not used, the relatively cheaper solenoid valve 332 can be used. Figure 2In the connection method described above, a solenoid valve 332 is installed on the bypass branch 320. During cold start, the solenoid valve 332 opens. Since the flow resistance of the open solenoid valve 332 branch is much smaller than that of the auxiliary radiator 310 branch, the flow rate is basically through the bypass branch 320, and only a small flow rate flows through the auxiliary radiator 310. Therefore, it will not cause any cooling to the water circuit. When the water circuit is hot and needs to dissipate heat, the solenoid valve 332 is closed, so that the flow rate in the circuit is all through the auxiliary radiator 310 for cooling.

[0032] Reference Figure 1 The coolant auxiliary flow path 300 also includes a hydrogen pump controller 350 and a booster module 360. The hydrogen pump controller 350 and the booster module 360 ​​are located after the auxiliary radiator 310 and the bypass branch 320, and the pipelines corresponding to the hydrogen pump controller 350, the booster module 360, and the air compressor controller 341 and the air compressor 342 are connected in parallel. After passing through the bypass branch 320, a portion of the coolant in the coolant auxiliary flow path 300 is diverted to the pipelines corresponding to the hydrogen pump controller 350, the booster module 360, and the air compressor controller 341 and the air compressor 342, respectively. The coolant carries away some of the heat generated by the hydrogen pump controller 350, the booster module 360, the air compressor controller 341, and the air compressor 342 during operation, thereby further accelerating the temperature rise of the coolant and improving the cold start speed of the fuel cell system.

[0033] Reference Figure 1 and Figure 2It is understood that the fuel cell stack body 100 also includes an air inlet 130 and an air outlet 140; the fuel cell cold start system also includes an air intake path 400 and an air outlet path 500; the inlet end of the air intake path 400 is used to allow external air to enter, and the air in the air intake path 400 flows through the air compressor 342. After the air compressor 342, the air intake path 400 is divided into an air purging branch 410 and an air intake branch 420. The air purging branch 410 is equipped with a first back pressure valve 411, and the outlet end of the air purging branch 410 is connected to the outer shell of the fuel cell stack body 100. The first back pressure valve 411 and the air purging branch 410 are connected. A second flow meter 414 is also provided between the outlet ends to measure the air flow rate blown out of the air purge branch 410. A fourth pressure sensor 415 is also provided at the input end of the first back pressure valve 411 to measure the air pressure entering the air purge branch 410. The outlet end of the air intake branch 420 is connected to the air inlet 130. A second back pressure valve 421 is provided on the air intake branch 420. The inlet end of the air outlet branch 500 is connected to the air outlet 140. The main control module is also used to change the conduction state of the first back pressure valve 411 and the second back pressure valve 421 according to the temperature values ​​detected by the first temperature sensor 210 and the second temperature sensor 220. The airflow direction is controlled by the first back pressure valve 411, and the compressed air after the air compressor 342 can pass through the outer shell of the fuel cell stack 100 instead of the stack body 100 through the air purging branch 410. Not flowing through the stack body 100 can prevent the air inlet pressure from being too high when the system is not started, thereby shortening the life of the stack body 100. Passing through the stack shell can utilize the heat of the compressed air to heat the stack body 100, so that the temperature of the stack body 100 can quickly reach the temperature point where it can operate normally, that is, quickly reach above the freezing point temperature, further improving the cold start efficiency of the fuel cell system.

[0034] It should be noted that a humidifier 460 is also installed on the air intake branch 420. Specifically, the air intake branch 420 passes through the humidification channel of the humidifier 460, and the air outlet branch 500 passes through the outlet channel of the humidifier 460. The compressed air and humid air exchange humidity, thereby humidifying the compressed air entering the fuel cell stack 100, maintaining the proton exchange membrane's moisture content at its optimal state, and improving the efficiency of the fuel cell system. After passing through the humidifier 460, the air outlet branch 500 also sequentially passes through the third back pressure valve 510, the mixing chamber 520, and the silencer 530.

[0035] Continue to refer to Figure 1 and Figure 2The air outlet flow path 500 is equipped with a third back pressure valve 510. The air purging branch 410 is equipped with an exhaust branch 412 connected to the front of the third back pressure valve 510 on the rear side of the output end of the first back pressure valve 411. The exhaust branch 412 is equipped with a ball valve 413. The main control module is specifically used to: control the opening degree of the first back pressure valve 411 to 50%, completely close the second back pressure valve 421 and completely open the third back pressure valve 510 when the temperature value detected by the second temperature sensor 220 is less than or equal to the preset first temperature threshold, and adjust the opening degree of the ball valve 413 so that part of the air in the inlet end of the air inlet flow path 400 is purged to the outer shell of the fuel cell body 100; and control the air compressor 342 to operate after waiting for a preset first time. It should be noted that the first temperature threshold mentioned above is 0℃. Specifically, the coolant outlet temperature is obtained by detecting the temperature value through the second temperature sensor 220. If the detected temperature is ≤0℃, the cold start procedure is initiated. The third back pressure valve 510 is fully opened, the second back pressure valve 421 is fully closed, and the opening of the first back pressure valve 411 is adjusted to 50%. The ball valve 413 is initially fully open (the ball valve 413 can be calibrated and adjusted to a certain opening degree according to the test results, and then the opening degree remains unchanged). After waiting for 6 seconds, the air compressor 342 is turned on, and the compressor speed is adjusted to the highest speed at a certain slope. At the same time, the opening of the first back pressure valve 411 is adjusted so that the air compressor 342 operates at the optimal efficiency point at this speed. According to the map at this speed, the optimal efficiency operating point is determined by the pressure to atmospheric pressure ratio monitored by the fourth pressure sensor 415 and the flow rate read by the flow meter.

[0036] Understandably, the air intake flow path 400 has an intercooler 430 located behind the output end of the air compressor 342. The intercooler 430 also has a coolant branch. The inlet of the coolant branch is connected to the pipe between the heater 250 and the outlet of the main coolant flow path, and the outlet is connected to the pipe between the first electrically controlled three-way valve 230 and the inlet of the main coolant flow path. The coolant in the coolant branch is used for heat exchange with the gas in the air intake flow path 400. The coolant in the main coolant flow path flows through the intercooler 430 and exchanges heat with the compressed air in the air intake flow path 400, thus cooling the compressed air and increasing the temperature of the coolant. The increased temperature of the coolant after passing through the intercooler 430 further improves the cold start efficiency of the fuel cell system. Simultaneously, the compressed air in the air intake flow path 400 blows any unused heat from the intercooler 430 to the outer casing of the fuel cell stack body 100 via the air purging branch 410. The exhaust branch 412, which is equipped with a ball valve 413, is to prevent excessive flow and velocity in the air purging branch 410 from affecting the internal components of the fuel cell stack. The ball valve 413 can adjust the flow distribution between the air purging branch 410 and the exhaust branch 412 by adjusting the opening of the ball valve 413.

[0037] Reference Figure 1 and Figure 2It is understood that the fuel cell stack body 100 also includes a hydrogen inlet 150 and a hydrogen outlet 160; the fuel cell cold start system also includes a hydrogen flow path 600, the first inlet of the hydrogen flow path 600 is connected to an external hydrogen supply device, the second inlet of the hydrogen flow path 600 is connected to the hydrogen outlet 160, and the outlet of the hydrogen flow path 600 is connected to the hydrogen inlet 150. The gas received at the first inlet of the hydrogen flow path 600 flows sequentially through a hydrogen filter 610, a shut-off valve 620, and a proportional valve 630 to the outlet of the hydrogen flow path 600. The gas received at the two inlet ends flows sequentially through the gas-liquid separator 640 and the circulating pump 650 to the outlet of the hydrogen flow path 600. The output end of the circulating pump 650 is connected to the output end of the proportional valve 630. The drain port of the gas-liquid separator 640 is connected to the output end of the third back pressure valve 510 through the drain valve 660, specifically to the mixing chamber 520. The gas-liquid separator 640 separates the water generated by the reaction and the remaining hydrogen. The separated water enters the mixing chamber 520 through the drain valve 660, and the remaining hydrogen can be re-entered into the fuel cell stack through the circulating pump 650 for recycling. The system includes a second pressure sensor 670 at the outlet of the hydrogen flow path 600 and a third pressure sensor 680 at the second inlet. The main control module is also used to: control the operation of the air compressor 342, open the shut-off valve 620, the proportional valve 630 and the circulating pump 650, and control the conduction state of the drain valve 660 when the temperature value detected by the second temperature sensor 220 is greater than the preset sixth temperature threshold, so as to adjust the gas pressure at the hydrogen inlet 150; and adjust the first back pressure valve 411, the second back pressure valve 421 and the third back pressure valve 510 to adjust the air flow rate at the inlet of the air intake flow path 400 and the gas pressure at the air inlet 130.The sixth temperature threshold is 2℃. Specifically, when the coolant outlet temperature detected by the second temperature sensor 220 is greater than 2℃, the air compressor 342 first reduces its speed at a certain slope until it reaches its minimum speed, then shuts off the air compressor 342. After 5 seconds, the shut-off valve 620, the proportional valve 630, and the circulation pump 650 are opened, and the hydrogen pressure reaches 125 kPa. Afterwards, drain valve 660 is opened for flushing. The opening interval of drain valve 660 is 1 second, and the opening time is 0.4 seconds. Flushing is performed 3 times. The hydrogen inlet 150 pressure of 125 kPa is established by adjusting the opening of circulating pump 650 and proportional valve 630. Drain valve 660 is closed for 2 seconds and opened for 0.5 seconds. Then, air compressor 342 is turned on and the compressor speed is adjusted to the highest speed at a certain slope. The first back pressure valve 411, the second back pressure valve 421 and the third back pressure valve 510 are adjusted to make the flow rate of the first flow meter 450 50 g / s and the pressure of the fuel cell stack air inlet 130 120 kPa, establishing... If the open-circuit voltage is determined to be ≥0.95V, the load is applied at a slope of 20A / s to the 90A idle point. The system then operates stably at the idle point while the water circuit heats up. At this time, the fuel cell stack 100 generates heat through reaction, the heater 250 heats the main flow path of the coolant, the intercooler 430 exchanges heat in the main flow path of the coolant, the air in the air intake branch 420 blows the surface of the fuel cell stack 100, and the coolant auxiliary flow path 300 absorbs heat from the heating components, all of which together heat the fuel cell stack 100, causing the coolant temperature to rise rapidly and greatly shortening the cold start time of the fuel cell system.

[0038] Understandably, the main control module is also used to: reduce the opening of the first back pressure valve 411 when the temperature detected by the first temperature sensor 210 is greater than the preset seventh temperature threshold, control the second back pressure valve 421 to be fully opened, and adjust the opening of the third back pressure valve 510 and the speed of the air compressor 342 so that the air flow rate at the inlet end of the air intake passage 400 and the air pressure at the air inlet 130 reach the standard of the working idle speed point of the fuel cell stack body 100. Specifically, when the first temperature sensor 210 detects that the coolant inlet temperature has been heated to >40°C, the air compressor 342 reduces its speed at a certain slope, and then adjusts the first back pressure valve 411 to a certain small opening degree (the specific opening degree is based on the actual calibration to a small flow rate. At this time, the main function of this circuit is to use a small flow rate to purge the outer shell of the fuel cell stack 100 to reduce the hydrogen concentration inside the shell, and it can also purge the condensate in the shell). The second back pressure valve 421 is fully opened, and the speed of the air compressor 342 and the third back pressure valve 510 are adjusted so that the flow rate of the first flow meter 450 and the pressure of the fuel cell stack air inlet 130 are at the idle point. The cold start ends, and normal load power is allowed.

[0039] This application integrates the main coolant flow path and the auxiliary coolant flow path 300, reducing the number of components and lowering costs. While the main coolant flow path heater 250 heats the coolant, the intercooler 430 also heats the coolant in the main coolant flow path. Furthermore, the heat that cannot be utilized by the intercooler 430 is reused by purging the outer casing of the fuel cell stack 100. At the same time, the heat generated by the operation of heat-generating components such as the air compressor 342 and the air compressor controller 341 is utilized. By combining these multiple methods, the cold start speed is improved.

[0040] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. A fuel cell cold start system, characterized in that, include: The fuel cell stack body includes a coolant inlet, a coolant outlet, an air inlet, and an air outlet; A main coolant flow path is provided, with a first temperature sensor at the outlet end of the main coolant flow path and connected to the coolant inlet. A second temperature sensor at the inlet end of the main coolant flow path is also provided and connected to the coolant outlet. The main coolant flow path passes through a first electrically controlled three-way valve, a main radiator, and a heater. The input end of the first electrically controlled three-way valve is connected to the inlet end of the main coolant flow path. The first output end of the first electrically controlled three-way valve is connected to the input end of the main radiator. The second output end of the first electrically controlled three-way valve is connected to the input end of the heater. The output end of the main radiator is connected to the output end of the heater and to the outlet end of the main coolant flow path. A coolant auxiliary flow path is provided, wherein the inlet end of the coolant auxiliary flow path is connected to the pipeline between the heater and the outlet end of the main coolant flow path, and the outlet end of the coolant auxiliary flow path is connected to the pipeline between the first electrically controlled three-way valve and the inlet end of the main coolant flow path. The coolant auxiliary flow path flows sequentially through the auxiliary radiator, the air compressor controller and the air compressor. The coolant auxiliary flow path is also provided with a bypass branch connected in parallel with the auxiliary radiator. Conduction control components are provided at the input end of the auxiliary radiator and the inlet end of the bypass branch. An air intake flow path is provided, with its inlet end for allowing external air to enter. The air in the air intake flow path flows through the air compressor. The air intake flow path is divided into an air purging branch and an air intake branch after the air compressor. A first back pressure valve is provided on the air purging branch. The outlet end of the air purging branch is connected to the outer shell of the fuel cell stack body. The outlet end of the air intake branch is connected to the air inlet. A second back pressure valve is provided on the air intake branch. An intercooler is provided on the rear side of the output end of the air compressor in the air intake flow path. The intercooler is also provided with a coolant branch. The inlet end of the coolant branch is connected to the pipeline between the heater and the outlet end of the main coolant flow path. The outlet end of the coolant branch is connected to the pipeline between the first electrically controlled three-way valve and the inlet end of the main coolant flow path. The coolant in the coolant branch is used to exchange heat for the gas in the air intake flow path. An air outlet flow path, wherein the inlet end of the air outlet flow path is connected to the air outlet; The main control module is used to change the conduction state of the first electrically controlled three-way valve and the conduction control component based on the temperature values ​​detected by the first temperature sensor and the second temperature sensor. The main control module is also used to change the conduction state of the first back pressure valve and the second back pressure valve according to the temperature values ​​detected by the first temperature sensor and the second temperature sensor.

2. The fuel cell cold start system according to claim 1, characterized in that, The conduction control component is a second electrically controlled three-way valve. The input end of the second electrically controlled three-way valve is connected to the pipeline between the heater and the outlet end of the main coolant flow path. The first output end of the second electrically controlled three-way valve is connected to the input end of the auxiliary radiator, and the second output end of the second electrically controlled three-way valve is connected to the inlet end of the bypass branch. The main control module is specifically used for: When the temperature value detected by the second temperature sensor is less than or equal to the preset first temperature threshold, the heater is turned on, and the opening of the first and second electrically controlled three-way valves is adjusted so that the coolant in the main flow path flows only through the branch with the heater, and the coolant in the auxiliary flow path flows only through the bypass branch.

3. The fuel cell cold start system according to claim 2, characterized in that, The coolant auxiliary flow path is equipped with a third temperature sensor at the pipeline after the auxiliary radiator and the bypass branch and before the air compressor. The main control module is also used for: When the temperature value detected by the first temperature sensor is greater than or equal to the preset second temperature threshold, the opening of the second electronically controlled three-way valve is adjusted so that the coolant in the coolant auxiliary flow path flows only through the branch equipped with the auxiliary radiator. When the temperature value detected by the third temperature sensor is greater than or equal to a preset third temperature threshold, the cooling fan of the auxiliary heat sink is turned on and the speed of the cooling fan of the auxiliary heat sink is controlled so that the temperature value detected by the third temperature sensor reaches a preset first target temperature value; wherein, the third temperature threshold is greater than the second temperature threshold. When the temperature value detected by the first temperature sensor is greater than or equal to the preset fourth temperature threshold, the heater is turned off, and the opening of the first electronically controlled three-way valve is adjusted so that the coolant in the main coolant flow path flows through the branch with the heater and the branch with the main radiator at the same time; wherein, the fourth temperature threshold is greater than the second temperature threshold. When the temperature value detected by the first temperature sensor is greater than or equal to the preset fifth temperature threshold, the cooling fan of the main radiator is turned on and the speed of the cooling fan of the main radiator is controlled so that the temperature value detected by the first temperature sensor reaches the preset second target temperature value, and the opening of the first electronically controlled three-way valve is adjusted so that the coolant in the main coolant flow path only flows through the branch where the main radiator is located; wherein, the fifth temperature threshold is greater than the fourth temperature threshold.

4. The fuel cell cold start system according to claim 1, characterized in that, The conduction control component is a solenoid valve, which is located on the bypass branch; the main control module is specifically used for: When the temperature value detected by the second temperature sensor is less than the preset first temperature threshold, the heater is turned on, and the opening degree of the first electronically controlled three-way valve is adjusted and the solenoid valve is opened, so that the coolant in the main flow path flows only through the branch with the heater, and the coolant in the auxiliary flow path flows only through the bypass branch. When the temperature value detected by the first temperature sensor is greater than the preset second temperature threshold, the solenoid valve is controlled to close so that the coolant in the coolant auxiliary flow path flows only through the branch with the auxiliary radiator.

5. The fuel cell cold start system according to claim 1, characterized in that, The coolant auxiliary flow path is also equipped with a hydrogen pump controller and a booster module. The hydrogen pump controller and the booster module are located after the auxiliary radiator and the bypass branch, and the pipelines corresponding to the hydrogen pump controller, the booster module, the air compressor controller, and the air compressor are connected in parallel.

6. The fuel cell cold start system according to claim 1, characterized in that, A third back pressure valve is provided in the air outlet flow path, and an exhaust branch connected to the front of the third back pressure valve is provided on the rear side of the output end of the first back pressure valve in the air purging branch, and a ball valve is provided on the exhaust branch; the main control module is specifically used for: When the temperature value detected by the second temperature sensor is less than or equal to the preset first temperature threshold, the opening degree of the first back pressure valve is controlled to 50%, the second back pressure valve is completely closed and the third back pressure valve is completely opened, and the opening degree of the ball valve is adjusted so that part of the air in the inlet end of the air intake airflow path is blown to the outer shell of the fuel cell body. Wait for the preset first time, then control the air compressor to operate.

7. The fuel cell cold start system according to claim 6, characterized in that, The fuel cell stack body also includes a hydrogen inlet and a hydrogen outlet; the fuel cell cold start system also includes a hydrogen flow path, the first inlet of the hydrogen flow path is connected to an external hydrogen supply device, the second inlet of the hydrogen flow path is connected to the hydrogen outlet, and the outlet of the hydrogen flow path is connected to the hydrogen inlet. Gas received at the first inlet of the hydrogen flow path flows sequentially through a hydrogen filter, a shut-off valve, and a proportional valve to the outlet of the hydrogen flow path. Gas received at the second inlet of the hydrogen flow path flows sequentially through a gas-liquid separator and a circulation pump to the outlet of the hydrogen flow path. The output of the circulation pump is connected to the output of the proportional valve. The drain port of the gas-liquid separator is connected to the output of the third back pressure valve via a drain valve. The main control module is also used for: When the temperature value detected by the second temperature sensor is greater than the preset sixth temperature threshold, the operating state of the air compressor is controlled, the shut-off valve, the proportional valve and the circulating pump are opened, and the conduction state of the drain valve is controlled to adjust the gas pressure at the hydrogen inlet. Adjust the first back pressure valve, the second back pressure valve, and the third back pressure valve to adjust the airflow rate at the inlet end of the air intake path and the air pressure at the air inlet.

8. The fuel cell cold start system according to claim 7, characterized in that, The main control module is also used to: when the temperature detected by the first temperature sensor is greater than the preset seventh temperature threshold, reduce the opening of the first back pressure valve, control the second back pressure valve to be fully opened, and adjust the opening of the third back pressure valve and the speed of the air compressor so that the air flow rate at the inlet end of the air intake path and the air pressure at the air inlet reach the standard of the working idle speed point of the fuel cell stack.

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