Fuel cell system and cooling unit therefor

Abstract

The embodiment of the present application discloses a fuel cell system, which comprises a stack and a cooling unit. The stack comprises a cooling liquid inlet and a cooling liquid outlet. The cooling unit comprises a tank, a booster pump, a pressure valve and a filter screen. The tank stores the cooling liquid inside, and the air pressure is not higher than the standard atmospheric pressure. One end of the booster pump is connected to the tank, and the other end is used to connect the cooling liquid inlet, so as to output the cooling liquid in the tank to the stack after boosting. One end of the pressure valve is connected to the tank, and the other end is used to connect the cooling liquid outlet, so as to keep the pressure of the cooling liquid in the stack higher than that in the tank. The filter screen is arranged upstream of the booster pump, and the mesh size of the filter screen is such that the size of the bubbles passing through the filter screen is smaller than the narrowest part of the cooling liquid flow channel after the bubbles are boosted by the booster pump. The application can avoid the bubbles from blocking the cooling liquid flow channel, and is beneficial to the discharge of the bubbles in the cooling liquid.

Description

Technical Field

[0001] This application relates to the field of fuel cells, and more specifically, to fuel cell systems and their cooling units. Background Technology

[0002] As a clean energy source, fuel cells can convert the chemical energy of hydrogen and oxygen into electrical energy directly through an electrochemical reaction under isothermal conditions without combustion. However, this process also generates heat and water. If the heat generated by the reaction is not removed in time, the accumulated heat may reduce the water content within the membrane, disrupting the water balance within the fuel cell stack and consequently affecting proton conduction and the lifespan of the fuel cell.

[0003] Currently, one side of the fuel cell electrode plate has a flow channel for hydrogen or oxygen, while the other side has a coolant channel to dissipate heat from the fuel cell. Common coolants include water, and heat dissipation efficiency is improved by lowering the coolant temperature and / or increasing the coolant flow rate.

[0004] However, existing fuel cells with coolant passages still suffer from insufficient heat dissipation. Summary of the Invention

[0005] One of the key points of this invention is the inventor's discovery of another reason for the insufficient heat dissipation in current fuel cells. The inventor found that air bubbles mixed in the coolant, when the coolant circulates repeatedly through the delicate flow channels of the fuel cell, gradually clog the channels, preventing the coolant from continuing to flow and thus hindering the timely dissipation of heat in that area. Based on the inventor's discovery, this invention proposes a fuel cell system and its cooling unit, aiming to solve the aforementioned problems in the prior art.

[0006] To achieve the above objectives, the present invention provides a cooling unit for cooling a fuel cell stack in a fuel cell system. The fuel cell stack includes a coolant inlet, a coolant outlet, and a coolant flow channel connecting the coolant inlet and the coolant outlet. The unit is characterized by comprising:

[0007] The enclosure contains coolant, and the air pressure inside the enclosure does not exceed the standard atmospheric pressure.

[0008] A booster pump, with one end connected to the housing and the other end connected to the coolant inlet, is used to pressurize the coolant in the housing and output it to the fuel cell stack.

[0009] A pressure valve, one end of which is connected to the housing and the other end of which is connected to the coolant outlet, to maintain the pressure of the coolant in the fuel cell stack higher than the pressure of the coolant in the housing;

[0010] A filter screen is located upstream of the booster pump, and its mesh size is such that the size of the air bubbles passing through the filter screen is smaller than the narrowest part of the coolant flow channel after being pressurized by the booster pump.

[0011] In some embodiments,

[0012] The cooling unit also includes:

[0013] A negative pressure device, connected to the housing, is used to reduce the pressure of the coolant inside the housing.

[0014] In some embodiments,

[0015] The cooling unit also includes:

[0016] A deionizer is connected between the booster pump and the housing.

[0017] In some embodiments,

[0018] The pressure valve is an adjustable pressure valve;

[0019] The cooling unit also includes:

[0020] A bubble sensor is positioned upstream of the pressure valve to detect the amount of bubbles at the coolant outlet;

[0021] The controller is connected to the bubble sensor, the pressure valve, and the booster pump. When the bubble quantity is greater than or equal to a preset bubble quantity, the controller increases the output pressure of the booster pump and the pressure threshold of the pressure valve by the same magnitude.

[0022] In some embodiments,

[0023] The cooling unit also includes:

[0024] A first pressure sensor, connected to the controller, is located downstream of the booster pump to detect the first pressure value of the coolant entering the fuel cell stack.

[0025] A second pressure sensor, connected to the controller, is positioned upstream of the pressure valve to detect a second pressure value of the coolant leaving the fuel cell stack.

[0026] The controller adjusts the output pressure of the booster pump and the pressure threshold of the pressure valve based on the difference between the first pressure value and the second pressure value.

[0027] In some embodiments,

[0028] When the controller detects that the difference between the first pressure value and the second pressure value is greater than or equal to a preset pressure value, it controls the booster pump to increase the output pressure by a first amplitude and controls the pressure valve to increase the pressure threshold by a second amplitude, wherein the first amplitude is greater than the second amplitude.

[0029] Furthermore, to achieve the above objectives, the present invention also proposes a fuel cell system, characterized in that it comprises:

[0030] The fuel cell stack includes a coolant inlet and a coolant outlet;

[0031] The cooling unit as described in the foregoing embodiments.

[0032] Furthermore, to achieve the above objectives, the present invention also proposes a fuel cell system, characterized in that it comprises:

[0033] The fuel cell stack includes a coolant inlet and a coolant outlet;

[0034] The cooling unit as described in the foregoing embodiments;

[0035] The third pressure sensor, connected to the controller, is used to measure the pressure of the reactant gas in the fuel cell stack and transmit it to the controller.

[0036] The pressure value of the reaction gas corresponds to a first pressure range of the output pressure of the booster pump and a second pressure range of the pressure valve.

[0037] The controller adjusts the booster pump within the first pressure range and the pressure valve within the second pressure range.

[0038] In some embodiments,

[0039] The fuel cell system also includes:

[0040] Output device, connected to the controller;

[0041] When the output pressure of the booster pump exceeds the first pressure range and / or the pressure threshold of the pressure valve exceeds the second pressure range, the controller controls the output device to output preset information.

[0042] Furthermore, to achieve the above objectives, the present invention also proposes a control method for a fuel cell system, characterized in that the method is used to control the fuel cell system as described in the foregoing embodiments, and is implemented by the controller, comprising:

[0043] Based on the pressure value of the reactant gas, determine the first pressure range of the booster pump output pressure and the second pressure range of the pressure valve;

[0044] When the bubble quantity is greater than or equal to the preset bubble quantity, the output pressure of the booster pump is increased within the first pressure range, and the pressure threshold of the pressure valve is increased by the same magnitude within the second pressure range.

[0045] When the difference between the first pressure value and the second pressure value is greater than or equal to a preset pressure value, the output pressure of the booster pump is increased by a first amplitude, and the pressure threshold of the pressure valve is increased by a second amplitude, wherein the first amplitude is greater than the second amplitude;

[0046] When the output pressure of the booster pump exceeds the first pressure range and / or the pressure threshold of the pressure valve exceeds the second pressure range, the output device is controlled to output preset information.

[0047] The cooling unit proposed in this application utilizes a booster pump to pressurize the coolant before outputting it to the fuel cell stack. A pressure valve connects to the coolant outlet of the fuel cell stack to maintain the pressure of the coolant inside the stack. Therefore, air bubbles in the coolant within the stack become smaller under high pressure, making them easier to pass through the narrow coolant channels. Furthermore, due to the pressure valve, the pressure of the coolant in the fuel cell stack is higher than the pressure of the coolant inside the tank. Therefore, after the coolant enters the tank, the air bubbles grow larger due to the pressure drop, making them more likely to aggregate and rise, and then be discharged from the coolant. Air bubbles that are not discharged from the coolant in the tank in time are filtered by a filter screen and pressurized by the booster pump, reducing their size to below the narrowest point of the coolant channels, thus preventing air bubbles from clogging the coolant channels.

[0048] The cooling unit proposed in this application has a bubble sensor installed at the coolant outlet of the fuel cell stack when the preset bubble amount is reached. The pressure threshold of the pressure valve is controlled according to the bubble amount detected by the bubble sensor. When the bubble amount is greater than the preset bubble amount, the pressure threshold of the pressure valve is increased to further reduce the bubble size in the fuel cell stack coolant. At the same time, the output pressure of the booster pump is increased by the same magnitude. This can help reduce the bubble size on the one hand, and avoid large fluctuations in the coolant flow rate on the other hand.

[0049] The cooling unit proposed in this application uses a first pressure sensor and a second pressure sensor to detect the first and second pressure values ​​at the inlet and outlet of the fuel cell coolant, respectively. When the difference between the two pressure values ​​is greater than a preset pressure value, it indicates that there is bubble blockage in the fuel cell. By controlling the booster pump to increase the output pressure by a first amplitude and controlling the pressure valve to increase the pressure threshold by a second amplitude, the bubble size is reduced. At the same time, the first amplitude being greater than the second amplitude increases the pressure difference across the bubble blockage, which is beneficial for expelling the blocked bubbles and solving the blockage problem. Attached Figure Description

[0050] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0051] The methods, systems, and / or procedures shown in the accompanying drawings will be further described with reference to exemplary embodiments. These exemplary embodiments will be described in detail with reference to the drawings. These exemplary embodiments are non-limiting exemplary embodiments, wherein reference numerals in the various views of the drawings represent similar mechanisms. It should be noted that the electrode thickness features are not shown in the cross-sectional views of this application to avoid conflict and clutter with the display of other features.

[0052] Figure 1 Here are structural diagrams of fuel cell systems involved in some embodiments of this application;

[0053] Figure 2 This is a structural diagram of a fuel cell system according to other embodiments of this application;

[0054] Figure 3 Here are structural diagrams of fuel cell systems involved in some embodiments of this application;

[0055] Figure 4 This is a structural diagram of a fuel cell system according to some embodiments of this application;

[0056] Figure 5 Here are structural diagrams of fuel cell systems according to other embodiments of this application;

[0057] Figure 6 This is a structural diagram of a fuel cell system according to some further embodiments of this application.

[0058] Icons: 100-Fuel stack, 110-Coolant inlet, 120-Coolant outlet, 200-Tank, 210-Coolant, 300-Boost pump, 400-Pressure valve, 500-Negative pressure device, 600-Deionizer, 700-Controller, 810-Bubble sensor, 820-First pressure sensor, 830-Second pressure sensor, 840-Third pressure sensor, 900-Output device. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0060] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0061] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0062] In the description of this application, it should be noted that the use of terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" to indicate orientation or positional relationships is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships commonly used when the product is in use. These terms are used solely for the convenience of describing this application and for 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. Furthermore, the use of terms such as "first" and "second" in the description of this application is only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0063] Furthermore, the use of terms such as "horizontal" and "vertical" in the description of this application does not imply that the component is required to be absolutely horizontal or suspended, but rather that it may be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but rather that it may be slightly tilted.

[0064] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0065] Please refer to Figure 1, Figure 1 This is a structural diagram of a fuel cell system according to an embodiment of this application. The fuel cell system includes a fuel cell stack 100 and a cooling unit connected to the fuel cell stack 100. The cooling unit is used to cool the fuel cell stack 100. The fuel cell stack 100 includes a coolant inlet 110, a coolant outlet 120, and a coolant flow channel connecting the coolant inlet 110 and the coolant outlet 120. Coolant 210 enters the coolant flow channel within the fuel cell stack 100 through the coolant inlet 110, absorbs the heat generated by the fuel cell stack 100 in the coolant flow channel, and then flows out from the coolant outlet 120, thereby reducing the temperature of the fuel cell stack 100.

[0066] The cooling unit includes a housing 200, a booster pump 300, a pressure valve 400, and a filter.

[0067] The housing 200 contains coolant 210, and the air pressure inside the housing 200 is not higher than the standard atmospheric pressure. As a feasible implementation, the housing 200 has an opening at the top that connects to the outside, so that the air pressure inside the housing 200 is equal to the standard atmospheric pressure.

[0068] One end of the booster pump 300 is connected to the housing 200 via a pipe, with the connection point located below the surface of the coolant 210 in the housing 200 to prevent air bubbles from being drawn in; the other end of the booster pump 300 is connected to the coolant inlet 110 via a pipe, and the booster pump 300 can pressurize the coolant 210 in the housing 200 and then output it.

[0069] One end of the pressure valve 400 is connected to the housing 200 via a pipe, with the connection point located below the surface of the coolant 210 in the housing 200 to prevent gas from being mixed in when the coolant 210 flows into the housing 200. The other end of the pressure valve 400 is connected to the coolant outlet 120 via a pipe.

[0070] A filter screen is positioned upstream of the booster pump 300. Its mesh size ensures that air bubbles passing through the filter, after being pressurized by the booster pump 300, are smaller than the narrowest point of the coolant flow channel, preventing air bubbles from clogging the coolant flow channel. As a feasible implementation, the filter screen is positioned inside the housing 200 at the pipe opening connecting to the booster pump 300. This limits the size of air bubbles flowing to the booster pump 300 after passing through the filter screen, while also not interfering with the process of air bubbles rising and discharging after settling within the housing 200. It is understood that since the air bubbles in the coolant 210 shrink under pressure after passing through the booster pump 300, the mesh size of the filter screen can be slightly larger than the narrowest point of the flow channel. The specific mesh size can be determined based on factors such as the size of the narrowest point of the flow channel and the pressure increase of the booster pump 300 on the coolant 210.

[0071] In this embodiment, the pressure valve 400 is a relief valve or other valve that can stabilize pressure. The pressure valve 400 maintains the upstream coolant 210 at a relatively high pressure and the downstream coolant 210 at a relatively low pressure, that is, keeps the pressure of the coolant 210 in the fuel cell stack 100 higher than the pressure of the coolant 210 in the housing 200. Specifically, the pressure threshold of the pressure valve 400 is 1.5-2 times the standard atmospheric pressure, which can ensure that the pressure of the coolant 210 in the fuel cell stack 100 is not lower than the pressure threshold, effectively reducing the bubble size in the coolant 210.

[0072] In this embodiment, the cooling unit uses a booster pump 300 to pressurize the coolant 210 and output it to the fuel cell stack 100. A pressure valve 400 is used to connect to the coolant outlet 120 of the fuel cell stack 100, ensuring that the pressure of the coolant 210 inside the fuel cell stack 100 is not less than the pressure threshold of the pressure valve 400, which is 1.5-2 times the standard atmospheric pressure. Under high pressure, air bubbles in the coolant 210 inside the fuel cell stack 100 become smaller, making it easier for them to pass through the narrow coolant channels. Furthermore, under the action of the pressure valve 400, the pressure of the coolant 210 in the fuel cell stack 100 is higher than the pressure of the coolant 210 inside the housing 200. After the coolant 210 enters the housing 200, the air bubbles grow larger due to the pressure drop, making them easier to aggregate and rise, and then be discharged from the coolant 210. Air bubbles that are not discharged in time are filtered by a filter screen and pressurized by the booster pump 300, reducing their size to below the narrowest point of the coolant channels, thus preventing air bubbles from clogging the coolant channels. The cooling unit in this embodiment can prevent air bubbles from clogging the flow channels of the coolant 210, which is beneficial for the discharge of air bubbles.

[0073] like Figure 2 As shown, in some embodiments, the cooling unit also includes a negative pressure device 500 and a deionizer 600. The deionizer 600 is connected between the booster pump 300 and the housing 200, and is used to remove ions from the coolant 210. The negative pressure device 500 is connected to the housing 200 and is used to reduce the pressure of the coolant 210 inside the housing 200. Specifically, the negative pressure device 500 can be a negative pressure pump or similar device, which reduces the pressure of the coolant 210 by lowering the gas pressure inside the housing 200 to below standard atmospheric pressure, thus helping the bubbles to grow larger and be discharged from the coolant 210. As an optional implementation, the housing 200 is also provided with a bubble removal device, which can be an ultrasonic defoamer.

[0074] like Figure 3As shown, in some embodiments, the cooling unit further includes a bubble sensor 810 and a controller 700. The bubble sensor 810 is disposed between the pressure valve 400 and the coolant outlet 120 to detect the amount of bubbles in the coolant 210 flowing out of the coolant outlet 120. In this embodiment, the pressure valve 400 is an adjustable pressure valve 400, and the controller 700 is connected to the bubble sensor 810, the pressure valve 400, and the booster pump 300. The controller 700 receives the detected amount of bubbles from the bubble sensor 810 and compares the amount of bubbles with a preset amount of bubbles. When the detected amount of bubbles is greater than or equal to the preset amount of bubbles, it indicates that too many bubbles have been generated in the fuel cell stack 100, which are prone to condensing into larger bubbles and thus blocking the coolant flow channel. At this time, the controller 700 will increase the pressure threshold of the pressure valve 400 by a certain amplitude to reduce the size of the bubbles in the coolant 210 of the fuel cell stack 100. At the same time, similar to the increase in pressure valve 400, controller 700 increases the output pressure of booster pump 300 to ensure that the difference between the output pressure of booster pump 300 and the pressure threshold of pressure valve 400 remains constant before and after the increase. On the one hand, increasing the output pressure of booster pump 300 can help increase the pressure of coolant 210 in fuel cell stack 100. On the other hand, ensuring a constant pressure difference can prevent large fluctuations in the flow rate of coolant 210.

[0075] like Figure 4As shown, in some embodiments, the cooling unit further includes a first pressure sensor 820 and a second pressure sensor 830. The first pressure sensor 820 is disposed between the booster pump 300 and the coolant inlet 110 to detect a first pressure value of the coolant 210 entering the fuel cell stack 100. The second pressure sensor 830 is disposed between the pressure valve 400 and the coolant outlet 120 to detect a second pressure value of the coolant 210 leaving the fuel cell stack 100. Both the first pressure sensor 820 and the second pressure sensor 830 are connected to the controller 700 to send the detected first and second pressure values ​​to the controller 700. The controller 700 adjusts the output pressure of the booster pump 300 and the pressure threshold of the pressure valve 400 based on the difference between the first and second pressure values ​​to maintain the cooling unit in normal operating condition as much as possible. Specifically, in this embodiment, the difference between the first and second pressure values ​​is used to help determine the flow of coolant 210 in the fuel cell stack 100: when the pressure difference is less than a preset pressure value, it indicates that the coolant 210 is flowing normally. At this point, with the bubble volume stable, the controller 700 fixes the pressure threshold of the pressure valve 400 and adjusts the output pressure of the booster pump 300 to maintain a stable difference between the first and second pressure values. When the pressure difference exceeds the preset pressure value, it indicates that bubbles are blocking the flow channel, causing poor flow of the coolant 210. In this case, the controller 700 controls the booster pump 300 to increase its output pressure by a first amplitude, and the pressure valve 400 to increase the pressure threshold by a second amplitude, thereby increasing the pressure of the coolant 210 in the fuel cell stack 100, reducing the bubble size. Since the first amplitude is greater than the second amplitude, this further increases the pressure difference across the blockage, which helps to expel the blocked bubbles and resolve the blockage problem.

[0076] Furthermore, in this embodiment, to prevent drastic pressure changes caused by the sudden unblocking of air bubbles, the output pressure of the booster pump 300 and the pressure threshold of the pressure valve 400 should increase gradually over time under the control of the controller 700. For example, when the difference ΔP between the first pressure value and the second pressure value is detected to be greater than the preset pressure value P0, the booster pump 300 is controlled to increase the output pressure P1 and the pressure valve 400 is controlled to increase the pressure threshold P2 during the first T1 time period, where P1 > P2. If no significant drop is observed in the curve of ΔP over time at the end of the first T1 time period, the booster pump 300 is controlled to increase the output pressure P1 and the pressure valve 400 is controlled to increase the pressure threshold P2 during the next T1 time period. If a significant drop is observed in the curve of ΔP over time at the end of the first T1 time period, the output pressure of the booster pump 300 and the pressure threshold of the pressure valve 400 are controlled to gradually return to the initial state.

[0077] like Figure 5As shown, in some embodiments, the fuel cell system further includes a third pressure sensor 840. The third pressure sensor 840 is connected to the controller 700 and is used to measure the pressure of the reactant gas in the fuel cell stack 100 and send the detected value to the controller 700. The fuel cell stack 100 includes multiple stacked individual cells, with the front and back sides of the electrode plates of each individual cell forming reactant gas flow channels and coolant flow channels, respectively. In this embodiment, there is a certain correspondence between the pressure of the reactant gas and the output pressure of the booster pump 300 and the pressure threshold of the pressure valve 400. It can be understood that when the output pressure of the booster pump 300 and the pressure threshold of the pressure valve 400 are too large or too small compared to the reactant gas pressure, the pressure difference between the two sides of the electrode plates may cause damage to the reactant gas flow channels and / or coolant flow channels of the electrode plates. Therefore, in this embodiment, while prioritizing the reaction rate, a first pressure range for the output pressure of the booster pump 300 and a second pressure range for the pressure valve 400 are obtained according to the pressure of the reactant gas. The controller 700 adjusts the booster pump 300 within the first pressure range and adjusts the pressure valve 400 within the second pressure range to ensure the safety of the electrode plate structure.

[0078] like Figure 6 As shown, in some embodiments, the fuel cell system also includes an output device 900. The output device 900 is connected to the controller 700. When the output pressure of the booster pump 300 exceeds a first pressure range and / or the pressure threshold of the pressure valve 400 exceeds a second pressure range, it indicates that the controller 700 has failed to control the amount of bubbles or blockage while ensuring the safety of the electrode structure. The controller 700 controls the output device 900 to output preset information to remind the user to stop the system for maintenance or take other control measures.

[0079] Some embodiments of this application relate to a control method for a fuel cell system, used to control the fuel cell system in the foregoing embodiments. This control method is implemented by a controller 700 and includes:

[0080] Step S100: Based on the pressure value of the reactant gas, determine the first pressure range of the output pressure of the booster pump 300 and the second pressure range of the pressure valve 400.

[0081] In step S200, when the amount of bubbles is greater than or equal to the preset amount of bubbles, the output pressure of the booster pump 300 is increased within the first pressure range, and the pressure threshold of the pressure valve 400 is increased by the same magnitude within the second pressure range.

[0082] In step S300, when the difference between the first pressure value and the second pressure value is greater than or equal to the preset pressure value, the output pressure of the booster pump 300 is increased by the first amplitude, and the pressure threshold of the pressure valve 400 is increased by the second amplitude, wherein the first amplitude is greater than the second amplitude.

[0083] In step S400, when the output pressure of the booster pump 300 exceeds the first pressure range and / or the pressure threshold of the pressure valve 400 exceeds the second pressure range, the control output device 900 outputs preset information.

[0084] By implementing this control method, the controller 700 in this embodiment can effectively control the amount of air bubbles in the coolant 210 of the fuel cell stack 100, and prevent or solve the problem of air bubbles clogging the coolant flow channel.

[0085] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A cooling unit for cooling a fuel cell stack (100) in a fuel cell system, the stack (100) comprising a coolant inlet (110), a coolant outlet (120), and a coolant flow channel connecting the coolant inlet (110) and the coolant outlet (120), characterized in that, include: The housing (200) contains coolant (210), and the air pressure inside the housing (200) is not higher than the standard atmospheric pressure; A booster pump (300) is connected at one end to the housing (200) and at the other end to the coolant inlet (110), and is used to boost the coolant (210) in the housing (200) and output it to the fuel cell stack (100). A pressure valve (400) is connected at one end to the housing (200) and at the other end to the coolant outlet (120) to maintain the pressure of the coolant (210) in the fuel cell stack (100) higher than the pressure of the coolant (210) in the housing (200). The pressure valve (400) is an adjustable pressure valve. A filter screen is disposed upstream of the booster pump (300), and its mesh size is such that the size of the air bubbles passing through the filter screen is smaller than the narrowest part of the coolant flow channel after being pressurized by the booster pump. A bubble sensor (810) is disposed upstream of the pressure valve (400) to detect the amount of bubbles at the coolant outlet (120); The controller (700) is connected to the bubble sensor (810), the pressure valve (400) and the booster pump (300). When the bubble quantity is greater than or equal to the preset bubble quantity, the controller increases the output pressure of the booster pump (300) and the pressure threshold of the pressure valve (400) by the same magnitude.

2. The cooling unit as described in claim 1, characterized in that, The cooling unit also includes: A negative pressure device (500) is connected to the housing (200) to reduce the pressure of the coolant (210) inside the housing (200).

3. The cooling unit as described in claim 1, characterized in that, The cooling unit also includes: A deionizer (600) is connected between the booster pump (300) and the housing (200).

4. The cooling unit as described in claim 1, characterized in that, The cooling unit also includes: A first pressure sensor (820), connected to the controller (700), is located downstream of the booster pump (300) to detect the first pressure value of the coolant (210) entering the fuel cell stack (100); A second pressure sensor (830), connected to the controller (700), is located upstream of the pressure valve (400) to detect a second pressure value of the coolant (210) leaving the fuel cell (100); The controller (700) adjusts the output pressure of the booster pump (300) and the pressure threshold of the pressure valve (400) based on the difference between the first pressure value and the second pressure value.

5. The cooling unit as described in claim 4, characterized in that, When the controller (700) detects that the difference between the first pressure value and the second pressure value is greater than or equal to a preset pressure value, it controls the booster pump (300) to increase the output pressure by a first amplitude and controls the pressure valve (400) to increase the pressure threshold by a second amplitude, wherein the first amplitude is greater than the second amplitude.

6. A fuel cell system, characterized in that, include: The fuel cell stack (100) includes a coolant inlet (110) and a coolant outlet (120). The cooling unit as described in any one of claims 1-5.

7. A fuel cell system, characterized in that, include: The fuel cell stack (100) includes a coolant inlet (110) and a coolant outlet (120). The cooling unit as described in claim 4 or 5; The third pressure sensor (840), connected to the controller (700), is used to measure the pressure value of the reactant gas in the fuel cell stack (100) and transmit it to the controller (700). The pressure value of the reactant gas corresponds to a first pressure range of the output pressure of the booster pump (300) and a second pressure range of the pressure valve (400); The controller (700) adjusts the booster pump (300) within the first pressure range and adjusts the pressure valve (400) within the second pressure range.

8. The fuel cell system as described in claim 7, characterized in that, The fuel cell system also includes: Output device (900) is connected to the controller (700); When the output pressure of the booster pump (300) exceeds the first pressure range and / or the pressure threshold of the pressure valve (400) exceeds the second pressure range, the controller (700) controls the output device (900) to output preset information.

9. A control method for a fuel cell system, characterized in that, The method is used to control the fuel cell system as described in claim 8, and is implemented by the controller (700), comprising: Based on the pressure value of the reactant gas, determine the first pressure range of the output pressure of the booster pump (300) and the second pressure range of the pressure valve (400); When the amount of bubbles is greater than or equal to the preset amount of bubbles, the output pressure of the booster pump (300) is increased within the first pressure range, and the pressure threshold of the pressure valve (400) is increased by the same magnitude within the second pressure range. When the difference between the first pressure value and the second pressure value is greater than or equal to a preset pressure value, the output pressure of the booster pump (300) is increased by a first amplitude, and the pressure threshold of the pressure valve (400) is increased by a second amplitude, wherein the first amplitude is greater than the second amplitude; When the output pressure of the booster pump (300) exceeds the first pressure range and / or the pressure threshold of the pressure valve (400) exceeds the second pressure range, the output device (900) is controlled to output preset information.

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