Fuel cell stack temperature control system

Abstract

The invention discloses a fuel cell stack temperature control system, and belongs to the technical field of fuel cells, the fuel cell stack temperature control system comprises an air processing assembly, a cooling circulation assembly and a flow adjusting device, the air processing assembly comprises an air compressor and an intercooler which are connected in sequence; external air is compressed by the air compressor, flows through the hot side of the intercooler, is conveyed to the cathode inlet and flows out from the cathode outlet; the cooling circulation assembly comprises a main loop arranged between the cooling liquid inlet and the cooling liquid outlet and a branch loop communicated with the main loop, a main water pump and a temperature control valve are arranged on the main loop, and cooling liquid is shunted from the main loop to the branch loop and flows back to the main loop through the cold side of the intercooler; the flow adjusting device is arranged on the main loop and / or the branch loop and used for adjusting the flow of cooling liquid flowing through the cold side of the intercooler. By integrating a collaborative operation mechanism of the air treatment assembly and the cooling circulation assembly and cooperating with the flow regulation device, high-precision dynamic regulation and control of the working temperature of the fuel cell stack are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and particularly to a temperature control system for a fuel cell stack. Background Art

[0002] As an efficient and clean energy conversion device, fuel cells have received extensive attention and applications in many fields such as automobiles and distributed power generation. As the core component of a fuel cell system, the stable operation and performance of a fuel cell stack highly depend on an appropriate operating temperature.

[0003] During the actual operation of a fuel cell, the fuel cell needs to obtain oxygen from the air and supply it as an oxidant required for the electrochemical reaction to the fuel cell stack. This is generally achieved by compressing external air with an air compressor and then inputting it into the cathode of the fuel cell stack. However, after being compressed by the air compressor, the temperature of the external air rises, and as the pressure after compression increases, the temperature of the external air will be much higher than the upper limit of the air temperature required by the cathode of the fuel cell stack, so additional cooling of the compressed air is required. In addition, during this process, a large amount of reaction heat is generated by the electrochemical reaction. If these heats cannot be discharged to the outside of the system in a timely and effective manner, the temperature of the fuel cell stack will rise rapidly. Excessive temperature will not only accelerate the aging and degradation of the internal materials of the fuel cell, but also reduce the power generation efficiency and even pose safety risks.

[0004] The currently existing fuel cell stack temperature control systems on the market usually adopt relatively basic cooling methods, such as simple air cooling or water cooling. Such cooling methods are often difficult to accurately adjust the cooling intensity according to the real-time heat generation situation of the fuel cell stack and the oxygen supply situation. In actual use, the temperature conditions of the cathode are easily disturbed by changes or offsets in the atmospheric environment, which will cause the fuel cell stack to not be able to achieve the best performance, and even cause irreversible damage to the performance due to improper thermal management, affecting the reliability and durability of the fuel cell stack. Summary of the Invention

[0005] The purpose of the present invention is to provide a temperature control system for a fuel cell stack to solve the technical problem in the prior art that the adaptability of the fuel cell stack cooling system is poor and it is impossible to adjust the cooling intensity in real time based on the actual situation.

[0006] With the above concept, the technical solution adopted by the present invention is as follows: A temperature control system for a fuel cell stack is applied to a battery stack main body. The battery stack main body has a coolant inlet, a coolant outlet, a cathode inlet, and a cathode outlet. This fuel cell stack temperature control system includes: An air treatment assembly, including an air compressor and an intercooler connected in sequence. External air is compressed by the air compressor and then flows through the hot side of the intercooler and is conveyed to the cathode inlet, and flows out from the cathode outlet; A cooling circulation assembly, including a main circuit arranged between the coolant inlet and the coolant outlet and a branch circuit communicated with the main circuit. A main water pump and a temperature control valve are arranged on the main circuit. The coolant is diverted from the main circuit to the branch circuit and returns to the main circuit after passing through the cold side of the intercooler; A flow regulating device is arranged on the main circuit and / or the branch circuit for regulating the flow rate of the coolant flowing through the cold side of the intercooler.

[0007] Preferably, the flow regulating device includes an auxiliary water pump. The auxiliary water pump is arranged on the branch circuit and is located between the main water pump and the intercooler. The auxiliary water pump is used for regulating the flow rate of the coolant flowing through itself.

[0008] Preferably, the flow regulating device includes a flow resistance regulating valve. The flow resistance regulating valve is arranged on the main circuit and is located between the main water pump and the coolant inlet. The flow resistance regulating valve is used for regulating the flow rate of the coolant flowing through itself. The input end of the branch circuit is located between the main water pump and the flow resistance regulating valve.

[0009] Preferably, the output end of the branch circuit is located between the flow resistance regulating valve and the coolant inlet.

[0010] Preferably, the battery stack body further includes a sealed box purge inlet and a sealed box purge outlet. Among the external air flowing through the hot side of the intercooler, a part is conveyed to the cathode inlet, and another part is conveyed to the sealed box purge inlet and flows out from the sealed box purge outlet.

[0011] Preferably, a first temperature sensor and a first pressure sensor are arranged at the coolant inlet, and a second temperature sensor and a second pressure sensor are arranged at the coolant outlet; and / or, a third temperature sensor and a third pressure sensor are arranged at the cathode inlet, and a fourth temperature sensor and a fourth pressure sensor are arranged at the cathode outlet.

[0012] Preferably, a humidifying device is arranged between the intercooler and the cathode inlet for increasing the humidity of the external air flowing through itself.

[0013] Preferably, a stop valve is arranged between the intercooler and the cathode inlet. The stop valve is used for opening or closing the passage between the intercooler and the cathode inlet; and / or, a back pressure regulating valve is arranged at the cathode outlet. The back pressure regulating valve is used for controlling the flow rate of the external air flowing out of the cathode outlet.

[0014] Preferably, the air treatment assembly includes an air filter, an air flow meter, and an air temperature sensor. The air filter is communicated with the input end of the air compressor and is used for filtering the external air. The air flow meter and the air temperature sensor are arranged between the air filter and the air compressor.

[0015] Preferably, a radiator is connected in parallel between the temperature control valve and the main water pump. The radiator is used for reducing the temperature of the coolant flowing through itself.

[0016] Advantages of the present invention: For the fuel cell stack temperature control system proposed by the present invention, the air treatment assembly arranges the air compressor and the intercooler in series. When the compressed high-temperature external air flows through the hot side of the intercooler, it can directly exchange heat with the coolant in the cooling cycle assembly, so as to quickly eliminate the additional heat introduced during the compression process before the external air enters the cathode inlet, and avoid the direct impact of the high-temperature external air on the inside of the battery stack body. At the same time, the cooling cycle assembly adopts a topological structure with a main circuit and a branch circuit connected in parallel. The main water pump drives the coolant to circulate in the battery stack body to absorb the heat generated by the electrochemical reaction, and part of the coolant is guided to the cold side of the intercooler through the branch circuit for secondary heat exchange. This shunt design enables the same coolant flow path to undertake the dual functions of heat dissipation of the battery stack body and pre-cooling of the intake air at the cathode inlet, improving the utilization rate of the coolant. The flow regulating device can accurately match the cooling demand based on the real-time working conditions by dynamically adjusting the flow rate of the coolant flowing through the cold side of the intercooler. When the load of the air compressor increases or the intake air temperature rises due to external environmental reasons, the flow rate of the coolant in the branch circuit can be increased to improve the heat exchange efficiency of the intercooler; on the contrary, when the load is low or the environment is low temperature, reducing the flow rate of the branch circuit can not only avoid the energy waste caused by excessive cooling, but also maintain the uniformity of the internal temperature of the battery stack body. Through this adaptive flow distribution mechanism, combined with the closed-loop regulation of the overall temperature of the main circuit by the temperature control valve, the fuel cell stack temperature control system can synchronously respond to the dual disturbances of the heat generation fluctuation of the battery stack body and the change of the intake air temperature. To sum up, the fuel cell stack temperature control system provided by the present invention realizes the high-precision dynamic regulation of the working temperature of the fuel cell stack by integrating the cooperative operation mechanism of the air treatment assembly and the cooling cycle assembly and cooperating with the flow regulating device. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of the fuel cell stack temperature control system provided by Embodiment 1 of the present invention; Figure 2 is a schematic structural diagram of the fuel cell stack temperature control system provided by Embodiment 2 of the present invention; Figure 3It is a schematic structural diagram of the fuel cell stack temperature control system provided in Embodiment 3 of the present invention.

[0018] In the figure: 100, battery stack main body; 101, coolant inlet; 102, coolant outlet; 103, cathode inlet; 104, cathode outlet; 105, enclosure purge inlet; 106, enclosure purge outlet; 1, air treatment assembly; 11, air compressor; 12, intercooler; 13, air filter; 14, air flow meter; 15, air temperature sensor; 2, cooling circulation assembly; 201, main circuit; 202, branch circuit; 21, main water pump; 22, temperature control valve; 23, humidifying device; 24, stop valve; 25, back pressure regulating valve; 26, radiator; 27, tail exhaust pipe; 31, auxiliary water pump; 32, flow resistance regulating valve; 41, first temperature sensor; 42, first pressure sensor; 51, second temperature sensor; 52, second pressure sensor; 61, third temperature sensor; 62, third pressure sensor; 71, fourth temperature sensor; 72, fourth pressure sensor. Detailed implementation manners

[0019] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where 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 by referring to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as a limitation to the present invention.

[0020] In the description of the present invention, unless otherwise clearly specified and defined, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0021] In the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact of the first and second features, or may include the non-direct contact of the first and second features but through other features between them. Moreover, the first feature being "above", "above", and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature is at a higher horizontal height than the second feature. The first feature being "below", "below", and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature is at a lower horizontal height than the second feature.

[0022] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. Embodiment 1

[0023] The embodiment of the present invention provides a fuel cell stack temperature control system, which can compress, cool and transport external air to the cathode of the fuel cell stack to provide oxygen required for the chemical reaction of the fuel cell, and cool the fuel cell stack to ensure the power generation efficiency.

[0024] Refer to Figure 1 , the fuel cell stack temperature control system provided by the embodiment of the present invention is applied to the battery stack main body 100. The battery stack main body 100 has a coolant inlet 101, a coolant outlet 102, a cathode inlet 103 and a cathode outlet 104. The fuel cell stack temperature control system includes an air treatment component 1, a cooling circulation component 2 and a flow regulating device. Among them, the air treatment component 1 includes an air compressor 11 and an intercooler 12 connected in sequence. The external air is compressed by the air compressor 11, flows through the hot side of the intercooler 12 and is transported to the cathode inlet 103, and flows out from the cathode outlet 104; the cooling circulation component 2 includes a main circuit 201 arranged between the coolant inlet 101 and the coolant outlet 102 and a branch circuit 202 communicated with the main circuit 201. A main water pump 21 and a temperature control valve 22 are provided on the main circuit 201. The coolant is diverted from the main circuit 201 to the branch circuit 202 and returns to the main circuit 201 after passing through the cold side of the intercooler 12; the flow regulating device is arranged on the main circuit 201 and / or the branch circuit 202 for regulating the flow rate of the coolant flowing through the cold side of the intercooler 12.

[0025] The fuel cell stack temperature control system proposed by the present invention arranges the air compressor 11 and the intercooler 12 in series in the air handling component 1. When the compressed high-temperature external air flows through the hot side of the intercooler 12, it can directly exchange heat with the coolant in the cooling cycle component 2, so as to quickly eliminate the extra heat introduced during the compression process before the external air enters the cathode inlet 103, and avoid the direct impact of the high-temperature external air on the inside of the fuel cell stack body 100. At the same time, the cooling cycle component 2 adopts a topological structure with a main loop 201 and a branch loop 202 in parallel. The main water pump 21 drives the coolant to circulate in the fuel cell stack body 100 to absorb the heat generated by the electrochemical reaction, and part of the coolant is guided to the cold side of the intercooler 12 through the branch loop 202 for secondary heat exchange. This shunt design enables the same coolant flow path to undertake the dual functions of heat dissipation of the fuel cell stack body 100 and pre-cooling of the air inlet at the cathode inlet 103, improving the utilization rate of the coolant. The flow regulating device can accurately match the cooling demand based on the real-time working conditions by dynamically adjusting the flow rate of the coolant flowing through the cold side of the intercooler 12. When the load of the air compressor 11 increases or the intake air temperature rises due to external environmental reasons, the flow rate of the coolant in the branch loop 202 can be increased to improve the heat exchange efficiency of the intercooler 12; conversely, when the load is low or the environment is cold, reducing the flow rate of the branch loop 202 can not only avoid the energy waste caused by excessive cooling, but also maintain the uniformity of the internal temperature of the fuel cell stack body 100. Through this adaptive flow distribution mechanism, combined with the closed-loop regulation of the overall temperature of the main loop 201 by the temperature control valve 22, the fuel cell stack temperature control system can synchronously respond to the dual disturbances of the heat generation fluctuation of the fuel cell stack body 100 and the change of the intake air temperature. In summary, the fuel cell stack temperature control system provided by the present invention realizes the high-precision dynamic regulation of the working temperature of the fuel cell stack by integrating the cooperative operation mechanism of the air handling component 1 and the cooling cycle component 2 and cooperating with the flow regulating device.

[0026] The specific structure and working principle of the fuel cell stack temperature control system will be elaborated below.

[0027] When the fuel cell stack temperature control system is in use, external air first enters the air compressor 11 and is pressurized and heated. Subsequently, it flows through the hot side channel of the intercooler 12. During this process, the high-temperature compressed air exchanges heat with the coolant flowing on the cold side of the intercooler 12. The cooled air is then transported to the cathode inlet 103 of the fuel cell stack main body 100 to participate in the electrochemical reaction. At the same time, the main water pump 21 drives the coolant to flow out from the coolant outlet 102, flows along the main circuit 201 through the temperature control valve 22, and then returns to the coolant inlet 101, forming a main circulation to continuously absorb the reaction heat generated inside the fuel cell stack main body 100. During the process of the coolant flowing through the main circuit 201, part of the coolant is diverted through the branch circuit 202 to the cold side channel of the intercooler 12, absorbs the heat of the compressed air through heat exchange, and then rejoins the main circuit 201. The flow regulating device dynamically adjusts the coolant distribution ratio of the main circuit 201 or the branch circuit 202 according to the real-time working conditions. When the output temperature of the air compressor 11 increases or the heat generation of the fuel cell stack main body 100 intensifies, the flow rate of the branch circuit 202 is increased to enhance the heat exchange capacity of the intercooler 12. At the same time, the temperature control valve 22 synchronously increases the flow rate of the main circuit 201 to enhance the overall heat dissipation intensity. When the heat load decreases, the adjustment is reversed to reduce the coolant consumption. Through the coordinated control of the flow rates of the main circuit 201 and the branch circuit 202, the system synchronously completes the dual tasks of cooling the fuel cell stack main body 100 and pre-cooling the intake air in a single cycle, and finally realizes the dynamic balance of the working temperature of the fuel cell stack.

[0028] The function of the main water pump 21 is to provide power for the flow of the coolant in the cooling circulation assembly 2, and to promote the circulation of the coolant in the main circuit 201 and the branch circuit 202. Its working principle is to suck the coolant from the coolant outlet 102 through mechanical power, and pressurize and transport it to the coolant inlet 101, forming a forced circulation path. The circulating flow of the coolant is realized, so as to take away the heat generated by the fuel cell stack and the heat of the air on the hot side of the intercooler 12.

[0029] The temperature control valve 22 is integrated in the main circuit 201 and is used to dynamically adjust the overall circulation intensity of the coolant in the main circuit 201 according to the actual temperature of the fuel cell stack main body 100. When the temperature of the fuel cell stack main body 100 rises, the valve opening of the temperature control valve 22 increases to increase the flow rate of the main circuit 201 and accelerate heat dissipation. When the temperature drops below the set threshold, the valve of the temperature control valve 22 is moderately closed to reduce the circulation flow rate and avoid over-cooling. This adjustment process forms a coordination with the flow regulating device of the branch circuit 202, which not only ensures the temperature stability of the fuel cell stack main body 100 itself, but also takes into account the heat exchange requirements of the intake air pre-cooling link, and realizes the precise heat balance under all working conditions.

[0030] Preferably, a radiator 26 is connected in parallel between the temperature control valve 22 and the main water pump 21. The radiator 26 is used to reduce the temperature of the coolant flowing through it. After flowing out of the coolant outlet 102 of the battery stack body 100, the coolant is divided into two paths under the drive of the main water pump 21. One path flows through the temperature control valve 22 and directly returns to the coolant inlet 101, and the other path enters the parallel-connected radiator 26 for forced heat dissipation. After the temperature of the coolant flowing through the radiator 26 is reduced through heat exchange with the ambient air or an external cold source, it re-enters the main circuit 201 and mixes with the non-dissipated coolant, and then flows into the coolant inlet 101 together. When the heat generated by the battery stack body 100 is low, the temperature control valve 22 reduces its opening degree, and most of the coolant preferentially flows through the radiator 26 for deep cooling to ensure that the temperature of the battery stack body 100 does not drop excessively under low-temperature conditions; when the heat generation surges, the opening degree of the temperature control valve 22 increases, allowing more non-dissipated coolant to quickly return to the battery stack body 100. At the same time, the radiator 26 continuously processes the shunt fluid to prevent the coolant temperature from rising due to insufficient heat dissipation capacity of the main circuit 201. As an independent heat dissipation unit, the radiator 26 forms a complement with the temperature control valve 22 of the main circuit 201. For example, in an extremely high-temperature environment, even if the temperature control valve 22 is fully open (no heat dissipation in the main circuit 201), effective temperature reduction can still be achieved by increasing the shunt ratio of the coolant flowing through the radiator 26; when the radiator 26 fails due to a fault, the system can completely rely on the temperature control valve 22 to adjust the flow rate of the main circuit 201 to maintain the basic heat dissipation function, improving the fault tolerance of the system. By adjusting the shunt ratio of the radiator 26, the temperature of the coolant entering the battery stack body 100 after mixing can be precisely controlled, avoiding the repeated heating energy consumption caused by excessive cooling of the coolant in the traditional series radiator 26.

[0031] In this embodiment, the flow rate regulating device includes an auxiliary water pump 31. The auxiliary water pump 31 is arranged in the branch circuit 202 and is located between the main water pump 21 and the intercooler 12. The auxiliary water pump 31 is used to regulate the flow rate of the coolant flowing through it.

[0032] Specifically, the auxiliary water pump 31 is arranged at the starting end of the coolant shunt in the branch circuit 202 (between the main water pump 21 and the intercooler 12). Its working principle is to directly control the flow rate of the coolant entering the cold side of the intercooler 12 by adjusting the valve opening degree. When the temperature of the compressed air output by the air compressor 11 rises or the heat generation of the battery stack body 100 intensifies, the auxiliary water pump 31 increases its opening degree, so that more coolant is shunted from the main circuit 201 to the branch circuit 202, thereby improving the heat exchange capacity of the intercooler 12 and quickly reducing the temperature of the compressed air; at the same time, the remaining coolant in the main circuit 201 can still adjust the flow rate through the temperature control valve 22 to ensure the heat dissipation requirements of the battery stack body 100 itself. Conversely, under low heat load conditions, the auxiliary water pump 31 reduces its opening degree to reduce the flow rate of the branch circuit 202 and avoid energy waste caused by excessive coolant flowing through the intercooler 12.

[0033] Through the independent regulation function of the auxiliary water pump 31, this design can accurately distribute the coolant ratio between the main circuit 201 and the branch circuit 202, thereby implementing decoupled control for the two links of intake air precooling and the heat dissipation of the battery stack main body 100. For example, when the ambient temperature suddenly rises, resulting in too high an initial temperature of the compressed air, the flow rate of the branch circuit 202 can be quickly increased by the auxiliary water pump 31 preferentially, and the intake heat input can be preferentially suppressed without significantly changing the overall flow rate of the main circuit 201, avoiding disturbing the temperature stability of the battery stack main body 100. This hierarchical control strategy not only simplifies the system response logic but also improves the reliability of dynamic regulation by reducing the control interference between the temperature control valve 22 and the auxiliary water pump 31. In addition, since the auxiliary water pump 31 directly acts on the fluid path of the branch circuit 202, its regulating action is less sensitive to the coolant pressure fluctuation, further enhancing the stability of the flow control.

[0034] Specifically, a first temperature sensor 41 and a first pressure sensor 42 are provided at the coolant inlet 101, and a second temperature sensor 51 and a second pressure sensor 52 are provided at the coolant outlet 102. The first temperature sensor 41 and the first pressure sensor 42 arranged at the coolant inlet 101 are used to monitor the temperature and pressure of the coolant before entering the battery stack main body 100 in real time, while the second temperature sensor 51 and the second pressure sensor 52 at the coolant outlet 102 synchronously detect the state of the coolant after heat dissipation. Based on the temperature difference and pressure difference data between the inlet and the outlet, the actual heat generation amount inside the battery stack main body 100 and the coolant circulation resistance can be accurately calculated, providing a direct basis for subsequent coolant flow control and the regulation of the temperature control valve 22.

[0035] And / or, a third temperature sensor 61 and a third pressure sensor 62 are provided at the cathode inlet 103, and a fourth temperature sensor 71 and a fourth pressure sensor 72 are provided at the cathode outlet 104. The third temperature sensor 61 and the third pressure sensor 62 at the cathode inlet 103 continuously collect the temperature and pressure values of the compressed air before entering the cathode of the battery stack main body 100. Combining the detection results of the fourth temperature sensor 71 and the fourth pressure sensor 72 at the cathode outlet 104, the heat exchange efficiency and gas diffusion state of the air flow path can be dynamically evaluated.

[0036] Specifically, regarding the cooperation between the temperature control valve 22 and the auxiliary water pump 31, there are the following four situations: When the third temperature sensor 61 at the cathode inlet 103 feeds back that the external air temperature at the cathode inlet 103 is lower than the cathode temperature set value and the first temperature sensor 41 at the coolant inlet 101 feeds back that the temperature at the coolant inlet 101 is lower than the coolant temperature set value, the rotational speed of the auxiliary water pump 31 is reduced and it is ensured that its rotational speed is higher than or equal to the minimum operating speed. At this time, the coolant flow rate through the intercooler 12 is reduced, and the heat exchange of the intercooler 12 is reduced, thereby increasing the temperature at the cathode inlet 103. At the same time, the opening degree of the temperature control valve 22 is reduced (by default, when the temperature control valve 22 is at the minimum opening degree, the external heat exchange system is cut off and in the "small circulation state", and when the temperature control valve 22 is at the maximum opening degree, all the flow passes through the external heat exchange system and is in the "large circulation state") and the instantaneous opening degree is maintained not less than the minimum opening degree to increase the temperature at the coolant inlet 101 of the stack.

[0037] When the third temperature sensor 61 at the cathode inlet 103 feeds back that the external air temperature at the cathode inlet 103 is higher than the cathode temperature set value and the first temperature sensor 41 at the coolant inlet 101 feeds back that the temperature at the coolant inlet 101 is higher than the coolant temperature set value, the rotational speed of the auxiliary water pump 31 is increased and it is ensured that its rotational speed is lower than or equal to the maximum operating speed. At this time, the coolant flow rate through the intercooler 12 is increased, and the heat exchange of the intercooler 12 is increased, thereby reducing the temperature at the cathode inlet 103. At the same time, the opening degree of the temperature control valve 22 is increased and the instantaneous opening degree is maintained not greater than the maximum opening degree to reduce the temperature at the coolant inlet 101.

[0038] When the third temperature sensor 61 at the cathode inlet 103 feeds back that the external air temperature at the cathode inlet 103 is lower than the cathode temperature set value but the first temperature sensor 41 at the coolant inlet 101 feeds back that the temperature at the coolant inlet 101 is higher than the coolant temperature set value, the rotational speed of the auxiliary water pump 31 is reduced and it is ensured that its rotational speed is higher than or equal to the minimum operating speed. At this time, the coolant flow rate through the intercooler 12 is reduced, and the heat exchange of the intercooler 12 is reduced, thereby increasing the temperature at the cathode inlet 103. At the same time, the opening degree of the temperature control valve 22 is increased and the instantaneous opening degree is maintained not greater than the maximum opening degree to reduce the temperature at the coolant inlet 101.

[0039] When the third temperature sensor 61 at the cathode inlet 103 feeds back that the external air temperature at the cathode inlet 103 is higher than the cathode temperature set value but the first temperature sensor 41 at the coolant inlet 101 feeds back that the temperature at the coolant inlet 101 is lower than the coolant temperature set value, the rotational speed of the auxiliary water pump 31 is increased and it is ensured that its rotational speed is lower than or equal to the maximum operating speed. At this time, the coolant flow rate through the intercooler 12 is increased, and the heat exchange of the intercooler 12 is increased, thereby increasing the temperature at the cathode inlet 103. At the same time, the opening degree of the temperature control valve 22 is reduced and the instantaneous opening degree is maintained not less than the minimum opening degree to increase the temperature at the coolant inlet 101.

[0040] The fuel cell stack temperature control system is equipped with a central control unit (CCU), which is electrically connected to various sensors. The first temperature sensor 41 at the coolant inlet 101 uses a thermistor to sense the coolant temperature, converting temperature changes into electrical signals. After amplification and filtering by the signal conditioning circuit, the signals are transmitted as digital signals via a data transmission line to the CCU. The first pressure sensor 42 uses a pressure-sensitive element to sense the coolant pressure, similarly converting pressure changes into electrical signals, which are then processed and transmitted to the CCU. The second temperature sensor 51 and the second pressure sensor 52 at the coolant outlet 102 follow the same principles as the sensors at the inlet, respectively collecting temperature and pressure data at the coolant outlet 102 and transmitting them to the CCU. The third temperature sensor 61 and the third pressure sensor 62 at the cathode inlet 103 measure the temperature and pressure of the compressed air entering the cathode, converting the sensed physical changes into electrical signals, which are then processed and transmitted to the CCU. The fourth temperature sensor 71 and the fourth pressure sensor 72 at the cathode outlet 104 collect temperature and pressure data of the air flowing out of the cathode and transmit them as electrical signals to the CCU.

[0041] After receiving data from the coolant inlet and outlet sensors, the CCU uses built-in algorithms to calculate the actual heat generated within the battery stack body 100 based on thermodynamic formulas and preset coolant specific heat capacity and mass parameters. Simultaneously, based on the principles of fluid mechanics, it evaluates the coolant circulation resistance based on the pressure difference between the coolant inlet 101 and coolant outlet 102, as well as relevant system piping parameters. For data from the cathode inlet and outlet sensors, the CCU runs a gas analysis software module. Combined with preset air property parameters, the CCU utilizes heat exchange principles and a gas diffusion model to analyze and compare temperature and pressure changes at the cathode inlet 103 and cathode outlet 104, dynamically assessing the heat exchange efficiency and gas diffusion state of the air flow path.

[0042] If the calculated heat generation from the battery stack increases and the coolant circulation resistance is normal, the CCU determines that increased heat dissipation is necessary. At this point, the CCU sends an electrical signal to the temperature control valve 22 to increase the valve opening, and simultaneously sends a signal to the main water pump 21 to appropriately increase its speed to accelerate coolant circulation and enhance heat dissipation. If the air flow path heat exchange efficiency is assessed to be low, the CCU sends control instructions to the air handling unit 1 based on the specific situation. For example, if it is determined that the intercooler 12 is insufficiently exchanging heat, the CCU sends an electrical signal to the auxiliary water pump 31 to increase its opening, allowing more coolant to flow through the cold side of the intercooler 12 and improving the intercooler's cooling capacity for the compressed air. If poor gas diffusion is detected, the CCU sends a command to the backpressure regulating valve 25 to adjust its opening to optimize the air pressure environment within the battery stack body 100, ensuring smooth gas diffusion and maintaining optimal conditions for the electrochemical reaction.

[0043] In particular, during the cold start phase, especially when the ambient temperature is extremely low, the fuel cell stack needs to quickly warm up to its normal operating temperature. During this phase, the system reduces the speed of the auxiliary water pump 31 to zero (i.e., completely stops operation), causing the coolant flow through the cold side of the intercooler 12 to approach zero, thereby minimizing the heat exchange function of the intercooler 12. Since the compressed air output by the air compressor 11 cannot be cooled when passing through the hot side of the intercooler 12, the heat it carries is completely retained. The high-temperature air is directly delivered to the cathode inlet 103, where the heat generated during the compression process is used to heat the interior of the fuel cell stack body 100, shortening the temperature rise time during the cold start phase.

[0044] When the temperature of the battery stack body 100 gradually rises but remains below the target temperature, a temperature threshold (e.g., 80% of the target temperature) is set for the auxiliary water pump 31 to activate. Below this threshold, the auxiliary water pump 31 maintains a minimal coolant flow at its lowest speed, avoiding the risk of freezing pipes due to a complete stop while also ensuring that the heat exchange capacity of the intercooler 12 remains extremely low, allowing the waste heat of the compressed air to continue accelerating the temperature rise of the battery stack body 100. Simultaneously, the closed-loop control strategy of the auxiliary water pump 31 is still in place during this phase, monitoring the temperature of the cathode inlet 103 in real time. If the temperature approaches or exceeds the set value, the auxiliary water pump 31 speed is gradually increased to restore the cooling function of the intercooler 12 and prevent overheating.

[0045] Specifically, during use, the CCU runs a self-test program, testing the circuit connections and functionality of all connected sensors and actuators. The CCU then reads preset low-temperature cold start parameters from an internal storage module, including the target start temperature, the minimum operating speed of the auxiliary water pump 31, the opening range of the temperature control valve 22, and the normal operating parameter ranges of each sensor, completing system initialization.

[0046] The first temperature sensor 41 at the coolant inlet 101 monitors the initial coolant temperature in real time and transmits this temperature data to the CCU in the form of an electrical signal. The CCU compares the received coolant temperature with a preset low-temperature cold start threshold. If the coolant temperature is below the threshold, the system is determined to be in a low-temperature cold start state and the low-temperature cold start control strategy is initiated.

[0047] When the control strategy is activated, the CCU sends a command to the air compressor 11 to operate at a specific starting speed to ensure that the compressed air can carry enough heat to heat the battery stack body 100. The starting speed is pre-set based on the heat required by the battery stack body 100 in a low-temperature environment and the performance of the air compressor 11.

[0048] Afterwards, the CCU controls the shut-off valve 24 to be in a closed state to prevent unheated cold air from entering the cathode and to avoid heat loss from the battery stack.

[0049] Meanwhile, the CCU sends a signal to reduce the rotational speed of the auxiliary water pump 31 to zero, making the coolant flow rate through the cold side of the intercooler 12 approach zero, maximizing the suppression of the heat exchange effect of the intercooler 12, and ensuring that the heat carried by the compressed air can be fully used for internal heating of the fuel cell stack main body 100.

[0050] Moreover, the CCU dynamically adjusts the rotational speed of the main water pump 21 according to the coolant temperature fed back by the first temperature sensor 41 and in combination with a preset heating rate model. In the initial stage, the rotational speed of the main water pump 21 is appropriately reduced to reduce the coolant circulation volume, enabling the heat inside the fuel cell stack main body 100 to accumulate and accelerating the heating speed. As the temperature of the fuel cell stack main body 100 gradually rises, the CCU gradually increases the rotational speed of the main water pump 21 to ensure that the coolant can transfer heat evenly and maintain the consistency of the temperature inside the fuel cell stack main body 100.

[0051] The temperature control valve 22 maintains a small opening degree, enabling the coolant to circulate inside the fuel cell stack main body 100 in a small loop, reducing the heat exchange with the external radiator 26, avoiding excessive reduction of the coolant temperature, and ensuring the heating efficiency of the fuel cell stack.

[0052] During the cold start process, each sensor continuously feeds back data to the CCU in real time. The third temperature sensor 61 at the cathode inlet 103 monitors the air temperature entering the cathode, and the temperature sensors at the coolant inlet 101 and the coolant outlet 102 respectively monitor the change in the coolant temperature.

[0053] Based on this real-time data, the CCU uses the built-in algorithm model to evaluate the heating situation of the fuel cell stack main body 100. If it is found that the air temperature at the cathode inlet 103 is too high, which may cause local overheating of the fuel cell stack, the CCU will appropriately increase the rotational speed of the auxiliary water pump 31 to allow a small amount of coolant to flow through the intercooler 12 and moderately cool the compressed air. If the overall heating speed of the fuel cell stack is too slow, the CCU will further optimize the rotational speed of the air compressor 11 or adjust the working states of the main water pump 21 and the temperature control valve 22 to accelerate the heating process.

[0054] When the temperature fed back by the first temperature sensor 41 at the coolant inlet 101 reaches the preset starting temperature threshold of the auxiliary water pump 31 (e.g., 80% of the target temperature), the CCU commands the auxiliary water pump 31 to operate at the lowest rotational speed to maintain a trace amount of coolant flow. On the one hand, this avoids the risk of pipeline freezing caused by complete stoppage, and on the other hand, it ensures that the heat exchange amount of the intercooler 12 is at an extremely low level, and continues to use the waste heat of the compressed air to accelerate the heating of the fuel cell stack.

[0055] Meanwhile, the CCU activates the closed-loop control strategy for the temperature of the cathode inlet 103. It compares in real time the temperature of the cathode inlet 103 fed back by the third temperature sensor 61 with the set value. If it detects that the temperature approaches or exceeds the set value, the CCU gradually increases the rotational speed of the auxiliary water pump 31 to restore the cooling function of the intercooler 12 and prevent the fuel cell stack from overheating.

[0056] As the temperature of the fuel cell stack continues to rise and approaches the target operating temperature, the CCU gradually adjusts the operating states of each component to enable a smooth transition to the normal operating mode. For example, it gradually increases the opening degree of the temperature control valve 22 to enable the coolant to circulate in a large loop, strengthening the heat exchange with the external radiator 26; it precisely adjusts the rotational speeds of the auxiliary water pump 31 and the air compressor 11 according to the actual heat generation of the fuel cell stack and the air intake temperature, etc., to ensure that the fuel cell stack can operate stably and efficiently after reaching the operating temperature.

[0057] Preferably, the branch circuit 202 has a parallel dual-channel structure, including a conventional cooling channel and a heat storage channel. The heat storage channel is filled with a phase change material whose solid-liquid phase change temperature matches the optimal operating temperature of the fuel cell stack. The inlet ends of the two channels are connected to the input end of the branch circuit 202 through a three-way switching valve, and the outlet ends jointly merge into the output end of the branch circuit 202. When the main body 100 of the fuel cell stack needs to be quickly heated up, the three-way switching valve guides the branch coolant to the heat storage channel. When flowing through the phase change material, it absorbs the latent heat stored therein, and the heated coolant enters the cold side of the intercooler 12 to exchange heat with the compressed air, rapidly increasing the air temperature at the cathode inlet 103; when enhanced heat dissipation is required, it is switched to the conventional cooling channel, and the coolant efficiently cools down through sensible heat exchange when flowing through the intercooler 12. The phase change material absorbs the waste heat of the coolant and stores thermal energy during the normal operation of the fuel cell (for example, when the coolant in the branch circuit 202 flows through the heat storage channel during the high-temperature operation of the main body 100 of the fuel cell stack, the phase change material absorbs heat and melts), and releases heat under cold start or low-temperature conditions (the phase change material solidifies and releases heat), realizing the temporal and spatial allocation of energy and improving the system's heating response speed; in addition, the dual-channel switching mechanism and the temperature control valve 22 of the main circuit 201 form a coordinated control. For example, during cold start in winter, it is switched to the heat storage channel and the opening degree of the temperature control valve 22 is adjusted smaller, enabling the high-temperature coolant to concentrate on heating the main body 100 of the fuel cell stack, which can save energy consumption compared with the traditional single-channel scheme.

[0058] Specifically, the switching logic of the three-way switching valve is linked with the temperature sensor network. When the third temperature sensor 61 detects that the temperature at the cathode inlet 103 is lower than the cathode temperature set value and the temperature at the coolant inlet 101 is also low, the controller preferentially switches to the heat storage channel and adjusts the auxiliary water pump 31 to increase the total branch flow rate, using the heat storage of the phase change material to rapidly increase the intake air temperature; after the main body 100 of the fuel cell stack enters the steady-state operation, it automatically switches back to the conventional channel and restores the branch flow rate reference value.

[0059] Preferably, a humidifying device 23 is provided between the intercooler 12 and the cathode inlet 103, which is used to increase the humidity of the external air flowing through itself. The compressed air flowing through the hot side of the intercooler 12 and preliminarily cooled can absorb moisture and increase humidity when flowing through the humidifying device 23 before entering the cathode, so that the air humidity is increased to the optimal range required for the electrochemical reaction. This process forms a synergy with the temperature control. The intercooler 12 first cools the high-temperature compressed air to an appropriate temperature range to avoid excessive evaporation of the humidifying moisture caused by high temperature, while the humidifying device 23 accurately compensates for the humidity on this basis to ensure that the air entering the cathode meets the dual parameter requirements of temperature and humidity. By compensating for humidity downstream of the intercooler 12, the moisture loss caused by temperature changes during the air compression and cooling process can be offset. Moreover, the sequential layout of the humidifying device 23 and the intercooler 12 forms a hierarchical processing logic of "adjusting temperature first and then humidity", which not only avoids the waste of moisture caused by high-temperature humidification (the moisture absorption capacity of high-temperature air is too strong and more water is consumed), but also prevents the icing risk that may be caused by low-temperature humidification (if humidification is carried out first and then cooling, the moisture may condense during subsequent cooling). In addition, the humidification process can utilize the waste heat of the system waste heat or the coolant circulation to realize the cascade utilization of heat energy and reduce the dependence on external humidification energy.

[0060] Among them, the humidifying device 23 can select existing equipment such as existing membrane humidifiers and steam injection humidifiers. Regarding its specific structure and working principle, it will not be elaborated here.

[0061] A stop valve 24 is provided between the intercooler 12 and the cathode inlet 103. The stop valve 24 is used to open or close the passage between the intercooler 12 and the cathode inlet 103, and can flexibly control the external air passage entering the cathode inlet 103. When the fuel cell stack is in a specific working condition, such as at the initial stage of startup, the shutdown stage or when the system needs to be overhauled, the passage between the intercooler 12 and the cathode inlet 103 can be cut off by closing the stop valve 24 to prevent air from entering the cathode, which helps to protect the internal structure of the fuel cell stack main body 100.

[0062] And / or, a back pressure regulating valve 25 is provided at the cathode outlet 104. The back pressure regulating valve 25 is used to control the flow rate of the external air flowing out of the cathode outlet 104 and accurately control the flow rate of the external air flowing out of the cathode outlet 104. By reasonably adjusting the external air flow rate, the air pressure environment inside the fuel cell stack main body 100 can be optimized to ensure that the electrochemical reaction proceeds under appropriate pressure conditions, thereby improving the power generation efficiency and performance stability of the fuel cell stack.

[0063] In addition, the fuel cell stack body 100 further includes a casing purge inlet 105 and a casing purge outlet 106. Among the external air flowing through the hot side of the intercooler 12, a part is delivered to the cathode inlet 103, and another part is delivered to the casing purge inlet 105 and flows out from the casing purge outlet 106. The compressed air pressurized by the air compressor 11 and flowing through the hot side of the intercooler 12 is divided into two independent airflows. The main airflow is delivered to the cathode inlet 103 along the conventional path to participate in the electrochemical reaction, while the other diverted airflow is guided to the casing purge inlet 105. After flowing through the inside of the casing, the diverted airflow is discharged out of the system from the purge outlet, continuously carrying away the water vapor, unreacted residual gas or possible impurities accumulated in the casing during this process, thereby maintaining the inside of the casing dry and clean. Through this design, by utilizing the pressure and waste heat characteristics carried by the compressed air itself, active gas replacement of the casing is achieved without additionally increasing a purge power source.

[0064] Furthermore, the air treatment assembly 1 includes an air filter 13, an air flow meter 14, and an air temperature sensor 15. The air filter 13 is communicated with the input end of the air compressor 11 and is used for filtering the external air. The air flow meter 14 and the air temperature sensor 15 are arranged between the air filter 13 and the air compressor 11. The air compressor 11 sucks the external air filtered by the air filter 13 from the atmospheric environment, and the air flow meter 14 and the air temperature sensor 15 respectively measure the flow rate and temperature of the external air entering the air compressor 11 after filtration. The compressed external air is cooled by the intercooler 12.

[0065] When the fuel cell system is operating, the shut-off valve 24 is opened, and the external air filtered by the air filter 13 is sucked into the air compressor 11 and compressed. The compressed external air is cooled by the intercooler 12 and is divided into the fuel cell stack casing purge gas and the fuel cell stack cathode gas. Among them, the fuel cell stack casing purge gas flows into the casing from the casing purge inlet 105 and flows out of the casing from the casing purge outlet 106. According to the humidification requirement of the gas at the cathode inlet 103, the cooled compressed air enters the humidification device 23 for humidification (for a system without external humidification, this component is not available), and enters the cathode inlet 103 after passing through the shut-off valve 24, the third temperature sensor 61, and the third pressure sensor 62. The external air flowing out of the fuel cell stack flows out from the cathode outlet 104, and the fourth temperature sensor 71 and the fourth pressure sensor 72 respectively measure the temperature and pressure of the external air. The back pressure regulating valve 25 controls the pressure of the cathode of the fuel cell stack body 100 following the pressure target, and after merging with the fuel cell casing purge gas downstream of the back pressure regulating valve 25, enters the tail pipe 27 and is discharged to the atmosphere.

[0066] More specifically, the hot side outlet of the intercooler 12 and the cathode inlet 103 are connected by a retractable bellows section. The input end of the air compressor 11 is also provided with an air pressure sensor, and the retractable bellows section is connected to the air pressure sensor signal. When the air pressure sensor detects a high-altitude and low-pressure environment, the bellows is driven to contract to shorten the flow path length from the intercooler 12 to the cathode inlet 103, thereby reducing the heat loss and pressure drop of the compressed air during the transportation process, ensuring that sufficient compressed air can efficiently enter the cathode inlet 103 and maintain the stable electrochemical reaction; at the same time, the speed of the air compressor 11 is adjusted in conjunction to compensate for the decrease in intake density, ensuring that the quality and flow of the compressed air entering the battery stack body 100 meet the reaction requirements, and avoiding the impact of insufficient air intake on power generation efficiency. When the air pressure sensor detects a low-altitude, high-pressure environment, it drives the bellows to extend to increase the heat dissipation area of the flow channel, which helps the compressed air to further dissipate heat naturally during transportation and reduce the cooling burden of the intercooler 12; and simultaneously increases the coolant flow on the cold side of the intercooler 12 to enhance the cooling effect of the intercooler 12, doubly ensuring that the air temperature entering the cathode inlet 103 is appropriate.

[0067] Preferably, the air treatment assembly 1 further includes a multi-stage temperature adjustment module, which is disposed between the hot-side outlet of the intercooler 12 and the cathode inlet 103. When the compressed air, initially cooled by the intercooler 12, flows through the multi-stage temperature adjustment module, it undergoes secondary temperature adjustment based on the real-time temperature requirements of the cathode inlet 103. When the ambient temperature is extremely low, the coolant flow rate on the cold side of the intercooler 12 is preferentially reduced to reduce heat exchange, thereby maintaining a relatively high temperature at the outlet of the intercooler 12. The compressed air is then precisely reheated by the multi-stage temperature adjustment module. When the ambient temperature is high, the intercooler 12 cools the air at maximum efficiency, and the multi-stage temperature adjustment module is shut down or in a low-power state.

[0068] Among them, the multi-stage temperature adjustment module can use an existing electric heater, a heat pump or a heat exchange gas-gas heater. Its working principle and specific structure are not described in detail here. Example 2

[0069] Figure 2 The second embodiment is shown, wherein the components identical or corresponding to those in the first embodiment are denoted by the corresponding reference numerals in the first embodiment. For simplicity, only the differences between the second embodiment and the first embodiment are described. The differences are: The flow regulating device includes a flow resistance regulating valve 32, which is arranged in the main circuit 201 and located between the main water pump 21 and the coolant inlet 101. The flow resistance regulating valve 32 is used to regulate the flow of coolant flowing through itself. The input end of the branch circuit 202 is located between the main water pump 21 and the flow resistance regulating valve 32.

[0070] Specifically, the flow resistance regulating valve 32 is installed on the main circuit 201 between the main water pump 21 and the coolant inlet 101. The input end of the branch circuit 202 is located at the shunt point downstream of the main water pump 21 and upstream of the flow resistance regulating valve 32. When the opening of the flow resistance regulating valve 32 decreases, the flow resistance of the main circuit 201 decreases, resulting in a decrease in pressure at the shunt point. Consequently, the pressure difference between the branch circuit 202 and the main circuit 201 decreases, causing the flow rate of the branch circuit 202 to naturally decrease. Conversely, when the opening of the flow resistance regulating valve 32 increases, the flow resistance of the main circuit 201 increases, the pressure difference of the branch circuit 202 increases, and more coolant is driven to enter the branch circuit 202 from the shunt point and flow through the cold side of the intercooler 12. Through the throttling-shunt coupling effect of the flow resistance regulating valve 32 on the fluid in the main circuit 201, the active regulation of the main circuit 201 is organically combined with the passive response of the branch circuit 202, forming a flow distribution mechanism with self-balancing characteristics.

[0071] More specifically, regarding the cooperation between the flow resistance regulating valve 32 and the auxiliary water pump 31, there are the following four situations: When the third temperature sensor 61 at the cathode inlet 103 feeds back that the external air temperature at the cathode inlet 103 is lower than the cathode temperature set value and the first temperature sensor 41 at the coolant inlet 101 feeds back that the temperature at the coolant inlet 101 is lower than the coolant temperature set value, the opening of the flow resistance regulating valve 32 is reduced (the opening is the minimum opening at the default minimum flow resistance and the maximum opening at the highest flow resistance), and it is ensured that its opening is higher than or equal to the minimum opening. At this time, the flow resistance (inlet and outlet pressure difference) allocated to the entire branch circuit 202 of the intercooler 12 decreases, the coolant flow rate through the intercooler 12 decreases, the heat exchange of the intercooler 12 is reduced, and thus the temperature at the cathode inlet 103 is increased. At the same time, the opening of the temperature control valve 22 is reduced and the instantaneous opening is maintained not less than the minimum opening to increase the temperature at the coolant inlet 101 of the stack.

[0072] When the third temperature sensor 61 at the cathode inlet 103 feeds back that the external air temperature at the cathode inlet 103 is higher than the cathode temperature set value and the first temperature sensor 41 at the coolant inlet 101 feeds back that the temperature at the coolant inlet 101 is higher than the coolant temperature set value, the opening of the flow resistance regulating valve 32 is increased, and it is ensured that its opening is less than or equal to the maximum opening. At this time, the flow resistance (inlet and outlet pressure difference) allocated to the entire branch circuit 202 of the intercooler 12 increases, the coolant flow rate through the intercooler 12 increases, the heat exchange of the intercooler 12 is increased, and thus the temperature at the cathode inlet 103 is reduced. At the same time, the opening of the temperature control valve 22 is increased and the instantaneous opening is maintained not greater than the maximum opening to reduce the temperature at the coolant inlet 101.

[0073] When the third temperature sensor 61 at the cathode inlet 103 feeds back that the external air temperature at the cathode inlet 103 is lower than the cathode temperature set value, but the first temperature sensor 41 at the coolant inlet 101 feeds back that the temperature at the coolant inlet 101 is higher than the coolant temperature set value, the opening of the flow resistance regulating valve 32 is reduced, and it is ensured that its opening is greater than or equal to the minimum opening. At this time, the flow resistance (inlet and outlet pressure difference) distributed by the 12 branch circuits 202 of the intercooler 12 is reduced, the coolant flow rate through the intercooler 12 is reduced, the heat exchange of the intercooler 12 is reduced, thereby increasing the temperature of the cathode inlet 103. At the same time, the opening of the temperature control valve 22 is increased and the instantaneous opening is maintained not greater than the maximum opening to reduce the temperature of the coolant inlet 101.

[0074] When the third temperature sensor 61 at the cathode inlet 103 feeds back that the external air temperature at the cathode inlet 103 is higher than the cathode temperature set value, but the first temperature sensor 41 at the coolant inlet 101 feeds back that the temperature at the coolant inlet 101 is lower than the coolant temperature set value, the opening of the flow resistance regulating valve 32 is increased, and it is ensured that its opening is less than or equal to the maximum opening. At this time, the flow resistance (inlet and outlet pressure difference) distributed by the 12 branch circuits 202 of the intercooler 12 is increased, the coolant flow rate through the intercooler 12 is increased, the heat exchange of the intercooler 12 is increased, thereby reducing the temperature of the cathode inlet 103. At the same time, the opening of the temperature control valve 22 is reduced and the instantaneous opening is maintained not less than the minimum opening to increase the temperature of the coolant inlet 101.

[0075] Preferably, the output end of the branch circuit 202 is located between the flow resistance regulating valve 32 and the coolant inlet 101. The output end of the branch circuit 202 is arranged on the section of the main circuit 201 between the flow resistance regulating valve 32 and the coolant inlet 101. When the system is in the low-temperature cold start state, the flow resistance regulating valve 32 is controlled to be less than or equal to the maximum opening. At this time, the flow rate of the main circuit 201 decreases significantly, while the branch circuit 202 obtains a higher proportion of the coolant flow rate due to the increased pressure difference at the shunt point. The coolant flowing through the cold side of the intercooler 12 increases in temperature after absorbing the heat of the compressed air, and then directly merges into the section of the main circuit 201 adjacent to the coolant inlet 101, mixing with a small amount of uncooled coolant in the main circuit 201 to form a mixed coolant with an increased temperature and enter the coolant inlet 101. Through the special topological principle of the coolant branch circuit 202, a relatively high proportion of the branch flow rate can be actively maintained in a low-temperature environment, continuously introducing the heat recovered by the intercooler 12 into the battery stack body 100, avoiding the heat loss caused by the repeated flow of the coolant through the radiator 26 in the traditional system, thereby improving the temperature uniformity inside the battery stack body 100; this design does not require additional electric heating devices, and realizes the self-supply of the cold start heat source only through the optimization of the flow path topology, which not only simplifies the system structure but also avoids the energy loss caused by auxiliary heating. For example, during a cold start at an extremely low temperature of -30°C, the temperature of the compressed air output by the air compressor 11 can reach above 80°C. After the coolant in the branch circuit 202 absorbs heat through the intercooler 12, the temperature rises to 40 - 50°C, and directly injecting it into the inlet of the battery stack body 100 can cause the core area inside to break through the freezing point within a few minutes, which is superior to the starting performance of the traditional series cooling architecture. In addition, under normal operating conditions, the flow resistance regulating valve 32 resumes its normal opening, and the preheated coolant output from the branch can still maintain an appropriate inlet temperature after mixing with the coolant in the main circuit 201, realizing a seamless switch between the cold start mode and the steady-state operation mode. Embodiment III

[0076] Figure 3 Embodiment III is shown, in which the same or corresponding components as those in Embodiment I and Embodiment II are denoted by the corresponding reference numerals in Embodiment I. For simplicity, only the differences between Embodiment III and Embodiment I and Embodiment II are described. The differences are as follows: The flow rate regulating device includes an auxiliary water pump 31 and a flow resistance regulating valve 32. The auxiliary water pump 31 is arranged in the branch circuit 202 and is located between the main water pump 21 and the intercooler 12. The auxiliary water pump 31 is used to regulate the flow rate of the coolant flowing through itself; the flow resistance regulating valve 32 is arranged in the main circuit 201 and is located between the main water pump 21 and the coolant inlet 101. The flow resistance regulating valve 32 is used to regulate the flow rate of the coolant flowing through itself. The input end of the branch circuit 202 is located between the main water pump 21 and the flow resistance regulating valve 32.

[0077] It can be understood that the technical solution of Embodiment 3 constructs a dual regulation mechanism for the flow rates of the main loop 201 and the branch loop 202 by setting the auxiliary water pump 31 and the flow resistance regulating valve 32 simultaneously. Its specific operation principle and process integrate the cooperative control logics of Embodiment 1 and Embodiment 2. When the system is running, the auxiliary water pump 31 directly affects the heat exchange amount of the intercooler 12 by actively regulating the flow rate of the branch loop 202, while the flow resistance regulating valve 32 indirectly adjusts the flow division ratio of the branch loop 202 by changing the flow resistance of the main loop 201, and the two form a complementary flow distribution strategy. For example, when the cathode inlet air temperature fluctuates rapidly, the auxiliary water pump 31 gives priority to quickly and roughly adjusting the branch flow rate, and the flow resistance regulating valve 32 finely corrects the flow rate of the main loop 201, and the dynamic balance of the coolant distribution is achieved through the cooperative action of the dual valves. This design further improves the adaptability of the system to complex working conditions by superimposing the control dimensions of Embodiment 1 and Embodiment 2. The specific implementation method is based on the teachings of the foregoing embodiments, so it will not be repeated here.

[0078] The above embodiments only illustrate the basic principles and characteristics of the present invention. The present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, the present invention has various changes and modifications, and these changes and modifications all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A fuel cell stack temperature control system is applied to a fuel cell stack main body (100). The fuel cell stack main body (100) has a coolant inlet (101), a coolant outlet (102), a cathode inlet (103), and a cathode outlet (104), and is characterized in that The fuel cell stack temperature control system includes: An air treatment component (1), including an air compressor (11) and an intercooler (12) connected in sequence. External air is compressed by the air compressor (11), flows through the hot side of the intercooler (12), and is transported to the cathode inlet (103), and flows out from the cathode outlet (104); A cooling circulation component (2), including a main circuit (201) arranged between the coolant inlet (101) and the coolant outlet (102) and a branch circuit (202) communicated with the main circuit (201). A main water pump (21) and a temperature control valve (22) are arranged on the main circuit (201). The coolant is diverted from the main circuit (201) to the branch circuit (202), and returns to the main circuit (201) after passing through the cold side of the intercooler (12); A flow regulating device, arranged on the main circuit (201) and / or the branch circuit (202), for regulating the flow rate of the coolant flowing through the cold side of the intercooler (12).

2. The fuel cell stack temperature control system according to claim 1, characterized in that, The flow regulating device includes an auxiliary water pump (31). The auxiliary water pump (31) is arranged on the branch circuit (202) and is located between the main water pump (21) and the intercooler (12). The auxiliary water pump (31) is used for regulating the flow rate of the coolant flowing through itself.

3. The fuel cell stack temperature control system according to claim 1, characterized in that The flow regulating device includes a flow resistance regulating valve (32). The flow resistance regulating valve (32) is arranged on the main circuit (201) and is located between the main water pump (21) and the coolant inlet (101). The flow resistance regulating valve (32) is used for regulating the flow rate of the coolant flowing through itself. The input end of the branch circuit (202) is located between the main water pump (21) and the flow resistance regulating valve (32).

4. The fuel cell stack temperature control system according to claim 3, characterized in that, The output end of the branch circuit (202) is located between the flow resistance regulating valve (32) and the coolant inlet (101).

5. The fuel cell stack temperature control system according to claim 1, wherein The battery stack main body (100) further includes a sealed box purge inlet (105) and a sealed box purge outlet (106). Among the external air flowing through the hot side of the intercooler (12), a part is transported to the cathode inlet (103), and another part is transported to the sealed box purge inlet (105) and flows out from the sealed box purge outlet (106).

6. The fuel cell stack temperature control system according to claim 1, wherein A first temperature sensor (41) and a first pressure sensor (42) are arranged at the coolant inlet (101), and a second temperature sensor (51) and a second pressure sensor (52) are arranged at the coolant outlet (102); And / or, a third temperature sensor (61) and a third pressure sensor (62) are arranged at the cathode inlet (103), and a fourth temperature sensor (71) and a fourth pressure sensor (72) are arranged at the cathode outlet (104).

7. The fuel cell stack temperature control system according to claim 1, characterized in that, A humidifying device (23) is arranged between the intercooler (12) and the cathode inlet (103) for increasing the humidity of the external air flowing through itself.

8. The fuel cell stack temperature control system according to claim 1, characterized in that, A shut-off valve (24) is provided between the intercooler (12) and the cathode inlet (103), and the shut-off valve (24) is used to open or close the passage between the intercooler (12) and the cathode inlet (103); And / or, a back-pressure regulating valve (25) is provided at the cathode outlet (104), and the back-pressure regulating valve (25) is used to control the flow rate of the external air flowing out of the cathode outlet (104).

9. The fuel cell stack temperature control system according to claim 1, characterized in that, The air treatment assembly (1) includes an air filter (13), an air flow meter (14) and an air temperature sensor (15). The air filter (13) is communicated with the input end of the air compressor (11) and is used to filter the external air. The air flow meter (14) and the air temperature sensor (15) are arranged between the air filter (13) and the air compressor (11).

10. The fuel cell stack temperature control system according to claim 1, wherein A radiator (26) is connected in parallel between the temperature control valve (22) and the main water pump (21), and the radiator (26) is used to reduce the temperature of the coolant flowing through itself.

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