A fuel cell cooling system

Abstract

The application relates to the technical field of fuel cells and discloses a fuel cell cooling system which comprises a stack, a cooling main circuit, a heating branch circuit, an exhaust branch circuit, a pressure detection device and a control device. The water pump rotating speed and the opening degree of a switching valve group are controlled by the control device, the heating branch circuit and the cooling main circuit are respectively exhausted, the exhaust state of the pipeline is effectively judged based on the change rate of the inlet stack pressure during the exhaust process, deviation caused by artificial judgment is avoided, and the exhaust efficiency is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fuel cell technology, and more particularly to a fuel cell cooling system. BACKGROUND

[0002] Before matching the whole vehicle, the fuel cell system needs to be filled with coolant and to be deaerated, and in the case of changing coolant into antifreeze in the season, the fuel cell system also needs to be deaerated, and the deaeration effect will directly affect the heat dissipation effect of the fuel cell system. If there is a large amount of air in the cooling water pipeline, the fuel cell system will be poor in heat dissipation, and then the local temperature of the fuel cell will be too high, and the pressure of the coolant will fluctuate greatly, and further, the fuel cell will be shut down.

[0003] The current method for deaerating the fuel cell cooling pipeline is to set a transparent silicone hose at the water outlet of the stack, and to deaerate the air in the cooling pipeline by manually squeezing, and the deaeration effect is detected by observing the amount of air bubbles carried in the transparent silicone tube. This method often has a large human accidental error, is not convenient for quantitative analysis, and when the fuel cell system is mounted on the vehicle, the transparent silicone tube at the stack outlet needs to be replaced with a black silicone tube of vehicle specification, and the human eye cannot be observed, so the deaeration state of the cooling pipeline cannot be judged. SUMMARY

[0004] The purpose of the present application is to provide a fuel cell cooling system, which deaerates each branch of the fuel cell cooling system respectively, and determines the deaeration cutoff time of different branches through the control system, so as to avoid the deviation caused by human judgment and improve the deaeration efficiency.

[0005] To achieve the above purpose, the fuel cell cooling system used by the present application comprises:

[0006] a stack, the stack having a liquid inlet and a liquid outlet;

[0007] a cooling main path, the cooling main path comprising a water pump, a switching valve group and a radiator connected in sequence by a pipeline, the radiator being connected with the liquid inlet through a first pipeline, and the water pump being connected with the liquid outlet through a second pipeline;

[0008] a heating branch, the heating branch being connected in parallel with the radiator, one end of the heating branch being connected with a first branch point of the first pipeline, and the other end being connected to the pipeline connecting the water pump and the radiator, and a PTC being arranged on the heating branch;

[0009] a water tank, the liquid outlet of the water tank being connected to the second pipeline;

[0010] an exhaust branch, one end of which is connected to the second supporting point of the first pipeline, and the other end of which is connected to the water tank, the second supporting point being located at the downstream end of the first supporting point;

[0011] a pressure detection device for detecting the inlet stack pressure in the second pipeline at the downstream end of the second supporting point;

[0012] the opening degree of the switching valve group can be adjusted between 0 and 100%, when the opening degree of the switching valve group is 0, the water pump is in communication with the PTC and is disconnected from the radiator, and when the opening degree of the switching valve group is 100%, the water pump is in communication with the radiator and is disconnected from the PTC;

[0013] a control device, which is electrically connected to the water pump, the switching valve group and the pressure detection device respectively, and is configured to:

[0014] start the water pump during the exhaust process, and control the rotating speed of the water pump to be an initial rotating speed;

[0015] exhaust the cooling main pipeline and the heating branch pipeline respectively;

[0016] when the cooling main pipeline is exhausted, the opening degree of the switching valve group is controlled to be 0, and when the heating branch pipeline is exhausted, the opening degree of the switching valve group is controlled to be 100%;

[0017] the exhaust of the cooling main pipeline and the exhaust of the heating branch pipeline both adopt an automatic emptying step, the automatic emptying step comprising:

[0018] obtain the actual inlet stack pressure detected by the pressure detection device, and calculate the actual inlet stack pressure change rate of the cooling liquid according to the actual inlet stack pressure;

[0019] compare the actual inlet stack pressure change rate with a preset set inlet stack pressure change rate;

[0020] when the actual inlet stack pressure change rate is less than the set inlet stack pressure change rate, the exhaust is completed.

[0021] as a preferred solution, the control device is further configured to:

[0022] after the exhaust of the cooling main pipeline and the exhaust of the heating branch pipeline, a residual air emptying step is further included;

[0023] the residual air emptying step specifically comprises:

[0024] control the opening degree of the switching valve group to be greater than 0 and less than 100%, and the water pump is in communication with the PTC and the radiator respectively;

[0025] The automatic emptying step is used to empty the internal residual air.

[0026] As a preferred solution, the control of the opening degree of the switching valve group greater than 0 and less than 100% specifically includes: controlling the opening degree of the switching valve group to be 20%, 50%, and 80% respectively.

[0027] As a preferred solution, the comparison of the actual inlet pressure change rate with the preset set inlet pressure change rate specifically includes:

[0028] The speed of the water pump is controlled to be an initial speed, and after a preset time, when the actual inlet pressure change rate is greater than or equal to the set inlet pressure change rate, the speed of the water pump is increased to a driving speed for operation until the actual inlet pressure change rate is less than the set inlet pressure change rate.

[0029] As a preferred solution, the switching valve group is a three-way valve, and the three interfaces of the three-way valve are in communication with the water pump, the radiator, and the PTC respectively.

[0030] As a preferred solution, a button is further included, and the button is electrically connected with the control device.

[0031] As a preferred solution, an exhaust method of a fuel cell cooling system is further provided, which includes:

[0032] Starting the water pump, and controlling the speed of the water pump to be an initial speed;

[0033] Exhausting the cooling main circuit and the heating branch circuit respectively;

[0034] When exhausting the cooling main circuit, the opening degree of the switching valve group is controlled to be 0, and when exhausting the heating branch circuit, the opening degree of the switching valve group is controlled to be 100%;

[0035] The automatic emptying step is used to exhaust the cooling main circuit and the heating branch circuit.

[0036] The actual inlet pressure detected by the pressure detection device is obtained, and the actual inlet pressure change rate of the cooling liquid is calculated according to the actual inlet pressure;

[0037] The actual inlet pressure change rate is compared with the preset set inlet pressure change rate;

[0038] When the inlet pressure change rate is less than the set inlet pressure change rate, the exhaust is completed.

[0039] As a preferred solution, after the exhausting of the cooling main circuit and the heating branch circuit respectively, a residual air emptying step is further included;

[0040] The residual air emptying step specifically includes:

[0041] The opening degree of the switching valve group is controlled to be greater than 0 and less than 100%, and the water pump is connected to the PTC and the radiator respectively;

[0042] The automatic emptying step is used to empty the internal residual air.

[0043] As a preferred solution, the control of the opening degree of the switching valve group greater than 0 and less than 100% specifically includes: the opening degree of the switching valve group is controlled to be 20%, 50% and 80% respectively.

[0044] As a preferred solution, the comparison of the actual inlet pressure change rate with the preset set inlet pressure change rate specifically includes:

[0045] The speed of the water pump is controlled to be the initial speed, and after a preset time, when the actual inlet pressure change rate is greater than the set inlet pressure change rate, the speed of the water pump is increased to the driving speed for operation until the actual inlet pressure change rate is less than the set inlet pressure change rate.

[0046] A fuel cell cooling system in the application controls the speed of the water pump and the opening degree of the switching valve group through a control device to exhaust the heating branch and the cooling main branch respectively, and air is exhausted from the exhaust branch. During the exhaust process, the inlet pressure in the second pipeline downstream of the second branch point is detected in real time through a pressure detection device, and the actual inlet pressure change rate is calculated by a control system, and the size of the actual inlet pressure change rate is compared with the preset set inlet pressure change rate. When the actual inlet pressure change rate is less than the set inlet pressure change rate, it indicates that the air in the cooling liquid has been exhausted at this time, and the exhaust is completed. The application can effectively judge the exhaust state of the pipeline, avoid the deviation caused by artificial judgment, affect the accuracy of the exhaust, and step by step exhaust different branches, effectively improve the exhaust efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0047] The application will be further described in detail below in combination with the drawings and preferred embodiments, but those skilled in the art will appreciate that the drawings are only drawn for the purpose of explaining the preferred embodiments and therefore should not be regarded as a limitation on the scope of the application. In addition, unless specifically indicated, the drawings are only intended to conceptually represent the composition or structure of the described objects and may include exaggerated displays, and the drawings are not necessarily drawn to scale.

[0048] Fig. 1 The structure and the flow direction of the cooling liquid of the application are shown in the schematic diagram;

[0049] Fig. 2 The control flow chart of the application is shown in the schematic diagram;

[0050] Wherein: 1, cooling main path; 11, water pump; 12, switching valve group; 13, radiator; 2, heating branch; 21, PTC; 3, exhaust branch; 4, electric pile; 41, liquid inlet; 42, liquid outlet; 5, pressure detection device; 6, water tank. DETAILED DESCRIPTION

[0051] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0052] Please see Figs. 1-2 A fuel cell cooling system provided by the embodiments of the present application comprises:

[0053] An electric pile 4, the electric pile 4 having a liquid inlet 41 and a liquid outlet 42;

[0054] A cooling main path 1, the cooling main path 1 comprising a water pump 11, a switching valve group 12 and a radiator 13 connected in sequence by pipelines, the radiator 13 being connected to the liquid inlet 41 by a first pipeline, and the water pump 11 being connected to the liquid outlet 42 by a second pipeline;

[0055] A heating branch 2, the heating branch 2 being connected in parallel to the radiator 13, one end of the heating branch 2 being connected to a first branch point of the first pipeline, and the other end being connected to a pipeline connecting the water pump 11 and the radiator 13, and the heating branch 2 being provided with a PTC 21;

[0056] A water tank 6, an outlet of the water tank 6 being connected to the second pipeline;

[0057] An exhaust branch 3, one end of the exhaust branch 3 being connected to a second branch point of the first pipeline, and the other end being connected to the water tank 6, the second branch point being located at a downstream end of the first branch point;

[0058] A pressure detection device 5 for detecting the inlet pressure of the electric pile at a downstream end of the second branch point in the second pipeline;

[0059] The opening degree of the switching valve group 12 can be adjusted between 0-100%, when the opening degree of the switching valve group 12 is 0, the water pump 11 is in communication with the PTC 21 and is disconnected from the radiator 13, and when the opening degree of the switching valve group 12 is 100%, the water pump 11 is in communication with the radiator 13 and is disconnected from the PTC 21;

[0060] A control device is electrically connected with the water pump 11, the switching valve group 12 and the pressure detecting device 5 respectively, and is configured to:

[0061] During the exhaust process, the water pump 11 is started, and the rotating speed of the water pump 11 is controlled to be an initial rotating speed;

[0062] The cooling main line 1 and the heating branch line 2 are respectively exhausted;

[0063] When the cooling main line 1 is exhausted, the opening degree of the switching valve group 12 is controlled to be 0, and when the heating branch line 2 is exhausted, the opening degree of the switching valve group 12 is controlled to be 100%;

[0064] The automatic exhaust step is adopted for both the exhaust of the cooling main line 1 and the exhaust of the heating branch line 2, and the automatic exhaust step comprises:

[0065] The actual charging pressure detected by the pressure detecting device 5 is obtained, and the actual charging pressure change rate of the cooling liquid is calculated according to the actual charging pressure;

[0066] The actual charging pressure change rate is compared with a preset set charging pressure change rate;

[0067] When the actual charging pressure change rate is less than the set charging pressure change rate, the exhaust is completed.

[0068] In the embodiment, before the exhaust, the cooling liquid is added to the water tank 6 to a proper position, the set charging pressure change rate is input, the water pump 11 is started, and the water pump 11 is adjusted to the initial rotating speed. The control system controls the opening degree of the switching valve group 12 to be 0, so that the water pump 11 is connected with the PTC 21, the heating branch line 2 is exhausted, the pressure detecting device 5 detects the charging pressure of the second line at the downstream end of the second branch point in real time, the control system calculates the actual charging pressure change rate according to the obtained charging pressure data, and compares the actual charging pressure change rate with the set charging pressure change rate. When the actual charging pressure change rate is less than the set charging pressure change rate, it is determined that the exhaust of the heating branch line 2 is completed. The control system controls the opening degree of the switching valve group 12 to be 100%, so that the water pump 11 is connected with the radiator 13, the cooling main line 1 is exhausted, and the automatic exhaust step is repeated. When the actual charging pressure change rate is less than the set charging pressure change rate, it is determined that the exhaust of the cooling main line 1 is completed, and the exhausted air is discharged through the exhaust branch line 3.

[0069] It is particularly pointed out that the exhaust sequence of each branch can be adjusted according to actual needs. It is shown by multiple experiments that the exhaust efficiency is higher when the heating branch 2 is first exhausted and then the cooling main branch 1 is exhausted. During the entire fuel cell cooling system exhaust process, the water tank 6 liquid level change needs to be noted at all times, and the cooling liquid is supplemented to a reasonable liquid level in a timely manner to ensure the smooth implementation of the exhaust step.

[0070] As a preferred solution, the control device is further configured to:

[0071] After the exhaust of the cooling main branch 1 and the heating branch 2, respectively, a residual air exhaust step is further included.

[0072] The residual air exhaust step specifically includes:

[0073] The opening degree of the switching valve group 12 is controlled to be greater than 0 and less than 100%, and the water pump 11 is connected to the PTC 21 and the radiator 13, respectively.

[0074] The automatic exhaust step is used to exhaust the internal residual air.

[0075] In this embodiment, because the opening degree of the switching valve group 12 is controlled from 0 to 100%, that is, from the switching of the water pump 11 connected to the PTC 21 to the switching of the water pump 11 connected to the radiator 13, the air in the cooling main branch 1 enters the heating branch 2 that has completed the exhaust at the time of switching, so that residual air exists in the heating branch 2. Therefore, the opening degree of the switching valve group 12 is adjusted to be greater than 0 and less than 100%, so that the water pump 11 is connected to the PTC 21 and the radiator 13, respectively, that is, the cooling main branch 1 and the heating branch 2 are connected, and the residual air exhaust step is started to exhaust the residual air in the pipeline, so as to ensure that the residual air is exhausted and improve the accuracy of the exhaust.

[0076] As a preferred solution, the control of the opening degree of the switching valve group 12 to be greater than 0 and less than 100% specifically includes: the opening degree of the switching valve group 12 is controlled to be 20%, 50%, and 80%, respectively. Under the three opening degrees, the residual air exhaust step is started to exhaust the residual air in the pipeline multiple times, so as to ensure that the residual air is exhausted and further improve the accuracy of the exhaust.

[0077] As a preferred solution, the comparison of the actual inlet pressure change rate with the preset set inlet pressure change rate specifically includes:

[0078] The speed of the water pump 11 is controlled to be an initial speed, and after a preset time, when the actual inlet pressure change rate is greater than or equal to the set inlet pressure change rate, the speed of the water pump 11 is increased to a driving speed for operation until the actual inlet pressure change rate is less than the set inlet pressure change rate.

[0079] In the embodiment, when the actual charging pressure change rate is greater than the set charging pressure change rate, it indicates that there is more air in the cooling liquid at this time, and at this time the control device needs to control the water pump 11 to increase the rotating speed, so that the cooling liquid flow rate in the cooling pipeline changes sharply, and the air in the cooling liquid is squeezed and discharged.

[0080] As a preferred solution, the switching valve group 12 is a three-way valve, and the three interfaces of the three-way valve are respectively communicated with the water pump 11, the radiator 13 and the PTC 21. The three-way valve can better control the communication of the water pump 11 with the PTC 21 and the radiator 13, and facilitate the adjustment of the opening degree of the three-way valve.

[0081] As a preferred solution, a button is further included, and the button is electrically connected with the control device. The button can be clicked to start the emptying program.

[0082] The application further provides an emptying method of a fuel cell cooling system, which comprises:

[0083] Starting the water pump 11, and controlling the rotating speed of the water pump 11 to be an initial rotating speed;

[0084] Respectively emptying the cooling main pipeline 1 and the heating branch pipeline 2;

[0085] When emptying the cooling main pipeline 1, the opening degree of the switching valve group 12 is controlled to be 0, and when emptying the heating branch pipeline 2, the opening degree of the switching valve group 12 is controlled to be 100%;

[0086] The emptying of the cooling main pipeline 1 and the emptying of the heating branch pipeline 2 both adopt an automatic emptying step, and the automatic emptying step comprises:

[0087] Obtaining an actual charging pressure detected by the pressure detection device 5, and calculating an actual charging pressure change rate of the cooling liquid according to the actual charging pressure;

[0088] Comparing the actual charging pressure change rate with a preset set charging pressure change rate;

[0089] When the charging pressure change rate is less than the set charging pressure change rate, the emptying is completed.

[0090] Further, after the respective emptying of the cooling main pipeline 1 and the heating branch pipeline 2, a residual air emptying step is further included;

[0091] The residual air emptying step specifically comprises:

[0092] Controlling the opening degree of the switching valve group 12 to be greater than 0 and less than 100%, and the water pump 11 is respectively communicated with the PTC 21 and the radiator 13;

[0093] The automatic emptying step is used to empty the internal residual air.

[0094] Further, the control of the opening degree of the switching valve group 12 greater than 0 and less than 100% specifically includes: controlling the opening degree of the switching valve group 12 to be 20%, 50%, and 80%, respectively.

[0095] Further, the comparison of the actual inlet pressure change rate with the preset set inlet pressure change rate specifically includes:

[0096] The rotational speed of the water pump 11 is controlled to be the initial rotational speed, and after a preset time, when the actual inlet pressure change rate is greater than or equal to the set inlet pressure change rate, the rotational speed of the water pump 11 is increased to the driving speed for operation until the actual inlet pressure change rate is less than the set inlet pressure change rate.

[0097] In the embodiment, the exhaust method of the fuel cell cooling system can exhaust each branch of the fuel cell cooling system respectively, and perform secondary exhaust on the residual air in the exhaust process, so as to ensure that the air in the pipeline is exhausted, the steps are simple, the exhaust efficiency is high, and the accuracy is strong.

[0098] In summary, the fuel cell cooling system provided in the embodiment can ensure the accuracy of the exhaust of the cooling system, shorten the exhaust time, and improve the exhaust efficiency.

[0099] This specification discloses the present application with reference to the accompanying drawings, and also enables those skilled in the art to implement the present application, including manufacturing and using any device or system, using appropriate materials, and using any combined method. The scope of the present application is defined by the claimed technical solutions, and includes other examples thought by those skilled in the art. As long as such other examples include structural elements not different from the literal language of the claimed technical solutions, or such other examples contain equivalent structural elements not substantially different from the literal language of the claimed technical solutions, such other examples should be considered to be within the protection scope determined by the claimed technical solutions of the present application.

Claims

1. A fuel cell cooling system, characterized by, The application relates to a cooling system for a fuel cell, which comprises: a fuel cell having an inlet and an outlet; a cooling main circuit comprising a water pump, a switching valve group and a radiator connected in sequence by pipelines, the radiator being connected to the inlet by a first pipeline, and the water pump being connected to the outlet by a second pipeline; a heating branch connected in parallel to the radiator, one end of the heating branch being connected to a first branch point of the first pipeline, and the other end being connected to a pipeline connecting the water pump and the radiator, a PTC being arranged in the heating branch; a water tank, the outlet of which being connected to the second pipeline; an exhaust branch, one end of which being connected to a second branch point of the first pipeline, and the other end being connected to the water tank, the second branch point being located downstream of the first branch point; a pressure detection device for detecting the inlet pressure of the second pipeline downstream of the second branch point; the opening degree of the switching valve group can be adjusted between 0 and 100%, when the opening degree of the switching valve group is 0, the water pump is communicated with the PTC and disconnected with the radiator, and when the opening degree of the switching valve group is 100%, the water pump is communicated with the radiator and disconnected with the PTC; a control device, which is electrically connected to the water pump, the switching valve group and the pressure detection device, and is configured to: start the water pump and control the rotating speed of the water pump to be an initial rotating speed during the exhaust process; exhaust the cooling main circuit and the heating branch respectively; control the opening degree of the switching valve group to be 0 when the cooling main circuit is exhausted, and control the opening degree of the switching valve group to be 100% when the heating branch is exhausted; both the exhaust of the cooling main circuit and the exhaust of the heating branch adopt an automatic exhaust step, the automatic exhaust step comprising: acquiring the actual inlet pressure detected by the pressure detection device, and calculating the actual inlet pressure change rate of the cooling liquid according to the actual inlet pressure; comparing the actual inlet pressure change rate with a preset set inlet pressure change rate; when the actual inlet pressure change rate is less than the set inlet pressure change rate, the exhaust is completed.

2. The fuel cell cooling system of claim 1, wherein, the control device is further configured to: after the exhaust of the cooling main circuit and the exhaust of the heating branch, a residual air exhaust step is further included; the residual air exhaust step specifically comprises: controlling the opening degree of the switching valve group to be greater than 0 and less than 100%, and the water pump being communicated with the PTC and the radiator respectively; adopting the automatic exhaust step to exhaust the internal residual air.

3. The fuel cell cooling system of claim 2, wherein, controlling the opening degree of the switching valve group to be greater than 0 and less than 100% specifically comprises: controlling the opening degree of the switching valve group to be 20%, 50% and 80% respectively.

4. The fuel cell cooling system of claim 1, wherein, the comparison of the actual inlet pressure change rate with the preset set inlet pressure change rate specifically comprises: controlling the rotating speed of the water pump to be the initial rotating speed, and after a preset time, when the actual inlet pressure change rate is greater than or equal to the set inlet pressure change rate, increasing the rotating speed of the water pump to a driving speed until the actual inlet pressure change rate is less than the set inlet pressure change rate.

5. The fuel cell cooling system of claim 1, wherein, The switching valve group is a three-way valve, and three interfaces of the three-way valve are communicated with the water pump, the radiator and the PTC respectively.

6. The fuel cell cooling system of claim 1, wherein, A button is further included, and the button is electrically connected with the control device.

7. An exhaust method of a fuel cell cooling system, characterized by, The method comprises: starting the water pump, and controlling the rotating speed of the water pump to be an initial rotating speed; respectively exhausting the cooling main circuit and the heating branch circuit; when exhausting the cooling main circuit, the opening degree of the switching valve group is controlled to be 0, and when exhausting the heating branch circuit, the opening degree of the switching valve group is controlled to be 100%. The automatic exhausting step is adopted for both exhausting the cooling main circuit and exhausting the heating branch circuit, and the automatic exhausting step comprises: acquiring an actual charging pressure detected by a pressure detection device, and calculating an actual charging pressure change rate of the cooling liquid according to the actual charging pressure; comparing the actual charging pressure change rate with a preset set charging pressure change rate; when the charging pressure change rate is less than the set charging pressure change rate, the exhausting is completed.

8. The exhaust method of a fuel cell cooling system according to claim 7, characterized by, After the step of respectively exhausting the cooling main circuit and the heating branch circuit, a residual air exhausting step is further included. The residual air exhausting step specifically comprises: controlling the opening degree of the switching valve group to be greater than 0 and less than 100%, and the water pump is communicated with the PTC and the radiator respectively; the automatic exhausting step is adopted to exhaust the internal residual air.

9. The exhaust method of a fuel cell cooling system according to claim 8, characterized by, The step of controlling the opening degree of the switching valve group to be greater than 0 and less than 100% specifically comprises: controlling the opening degree of the switching valve group to be 20%, 50% and 80% respectively.

10. The exhaust method of a fuel cell cooling system according to claim 7, characterized by, The step of comparing the actual charging pressure change rate with the preset set charging pressure change rate specifically comprises: controlling the rotating speed of the water pump to be the initial rotating speed, and after a preset time, when the actual charging pressure change rate is greater than or equal to the set charging pressure change rate, increasing the rotating speed of the water pump to a driving speed until the actual charging pressure change rate is less than the set charging pressure change rate.

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