In-situ testing device and method for proton exchange membrane fuel cell under cold-heat shock cycle

Abstract

This invention relates to an in-situ testing device and method for thermal shock cycles of proton exchange membrane fuel cells. The device includes a heat source module, a cold source module, and a transition module. The heat source module is connected to the test piece via a heat source pipe to form a high-temperature shock circuit. The cold source module is connected to the test piece via a cold source pipe to form a low-temperature shock circuit. The transition module is connected to the test piece via a transition pipe. The heat source pipe is divided into a heat source inlet pipe and a heat source return pipe, with a heat source pump installed on the heat source inlet pipe and a heat source solenoid valve installed on the heat source return pipe. The cold source pipe is divided into a cold source inlet pipe and a cold source return pipe, with a cold source pump installed on the cold source return pipe and a cold source solenoid valve installed on the cold source return pipe. Compared with the prior art, this invention adds a transition module to maintain the temperature stability of the high and low temperature liquids in the entire testing device for a long time, thereby enabling efficient evaluation of the high and low temperature durability and lifespan of the in-pile materials and component structures.

Description

Technical Field

[0001] This invention relates to the field of proton exchange membrane fuel cell durability testing, and in particular to an in-situ testing apparatus and method for thermal shock cycles of proton exchange membrane fuel cells. Background Technology

[0002] The operating temperature range of proton exchange membrane fuel cells (PEMFCs) is typically -40°C to 90°C. Within this temperature range, all components and structures within the stack must maintain stability and reliability for long-term operation. For the development of new fuel cell materials and components, such as novel sealing materials, membrane electrode structures, composite bipolar plate materials, and metal bipolar plate coatings, it is difficult to accurately assess their durability and stability under actual operating temperatures and temperature cycling conditions using non-in-situ / ex-situ experimental methods. Therefore, an in-situ experimental device is needed that can simulate the actual operating temperature of a PEMFC and rapidly switch between high and low temperature environments, thereby efficiently evaluating the lifespan and durability of the fuel cell stack and its components.

[0003] In the prior art, Chinese patent CN217277990U provides a high and low temperature cycle life testing system for fuel cell materials. This system switches between high and low temperatures in the tested fuel cell by setting up cold and hot circulation networks. This external heating / cooling method results in heat loss, and there is a delay in temperature transfer to the inside of the fuel cell. Furthermore, it is difficult to maintain a uniform internal temperature below -30°C when there are multiple cells. Chinese patent CN114006012A provides a high and low temperature scouring test system for fuel cell bipolar plates. However, due to the mixing of high and low temperature liquids, it is difficult for this device to maintain the ideal ultra-low temperature (e.g., -35°C) for extended periods when performing hundreds of thousands or more high and low temperature cycle tests. Moreover, prolonged operation of the environmental chamber leads to excessive laboratory energy consumption, making it economically unsatisfactory.

[0004] Chinese patent CN113237823A discloses a high and low temperature cycling test system for proton exchange membrane fuel cells. A single cell or stack is used as the test piece. The low-temperature cycling impact structure and the high-temperature cycling impact structure are respectively equipped with a working channel and a self-circulation channel. The self-circulation channel can alleviate the working pressure of the internal drive pumps of the heat source and cold source, avoiding pressure buildup and ensuring effective rapid switching between hot and cold. During thermal shock testing, high-temperature and low-temperature liquids need to be alternately circulated into the test piece. However, after multiple thermal shocks, the high-temperature liquid residue in the test piece and the inlet / outlet pipes of the battery water chamber mixes with the cold source, causing the cold source to heat up. Conversely, the low-temperature liquid residue in the test piece and the inlet / outlet pipes of the battery water chamber mixes with the heat source, causing the heat source to cool down. Therefore, prolonged thermal shock testing is not possible, or additional devices are needed to maintain the temperature stability of the cold and heat sources.

[0005] In summary, there is a need to develop a stable, reliable, wide-range, precisely temperature-controlled, and rapidly switching cyclic shock in-situ experimental device for the internal environment of fuel cells. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects of the prior art by providing an in-situ testing device and method for thermal shock cycles of proton exchange membrane fuel cells.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A proton exchange membrane fuel cell thermal shock cycle in-situ testing device includes a heat source module, a cold source module, and a transition module. The heat source module is connected to the test piece via a heat source pipe to form a high-temperature shock circuit. The cold source module is connected to the test piece via a cold source pipe to form a low-temperature shock circuit. The transition module is connected to the test piece via a transition pipe. Multiple one-way valves are installed on the heat source pipe, cold source pipe, and transition pipe. The heat source pipe is divided into a heat source inlet pipe and a heat source return pipe, with a heat source pump installed on the heat source inlet pipe and a heat source solenoid valve installed on the heat source return pipe. The cold source pipe is divided into a cold source inlet pipe and a cold source return pipe, with a cold source pump installed on the cold source return pipe and a cold source solenoid valve installed on the cold source return pipe.

[0009] The first design scheme for the transition device is:

[0010] The transition device is a nitrogen source module. The heat source pump and the cold source pump are magnetically driven gear pumps. The transition pipeline is divided into a first purging channel and a second purging channel. The nitrogen source module is connected to the test piece and the heat source module in sequence through the first purging channel, and the second purging channel is connected to the test piece and the cold source module in sequence.

[0011] Furthermore, the first purge channel includes a first air inlet pipe and a heat source return pipe, and a first connection point is provided between the heat source pump and the test piece. The two ends of the first air inlet pipe are respectively connected to the nitrogen source module and the first connection point. The second purge channel includes a second air inlet pipe and a cold source return pipe, and a second connection point is provided between the cold source pump and the test piece. The two ends of the second air inlet pipe are respectively connected to the nitrogen source module and the second connection point. A first air inlet solenoid valve and a second air inlet solenoid valve are respectively provided on the first air inlet pipe and the second air inlet pipe.

[0012] Furthermore, the nitrogen source module includes a nitrogen source and a pressure regulating valve.

[0013] The second design scheme for the transition device is:

[0014] The transition device is an auxiliary cold source module. The transition module is connected to the test piece through a transition pipe to form a transition loop. The transition pipe is divided into a transition inlet pipe and a transition return pipe. A transition pump is installed on the transition inlet pipe. The transition pump is a magnetic drive gear pump. The heat source pump and the cold source pump are water pumps.

[0015] Furthermore, a third connection point is provided between the heat source pump and the test piece. The two ends of the transition inlet pipe are respectively connected to the auxiliary cold source module and the third connection point. A fourth connection point is provided between the heat source solenoid valve and the heat source module. The two ends of the transition return pipe are respectively connected to the auxiliary cold source module and the fourth connection point. A transition return solenoid valve is provided on the transition return pipe.

[0016] Furthermore, it also includes a heat source branch pipe and a cold source branch pipe. A fifth connection point is provided between the heat source pump and the third connection point, and a sixth connection point is provided between the heat source module and the fourth connection point. The two ends of the heat source branch pipe are respectively connected to the fifth connection point and the sixth connection point to form a heat source circulation loop including the heat source module and the heat source pump. A heat source circulation solenoid valve is provided on the heat source branch pipe. A seventh connection point is provided between the cold source pump and the test piece, and an eighth connection point is provided between the cold source solenoid valve and the cold source module. The two ends of the cold source branch pipe are respectively connected to the seventh connection point and the eighth connection point to form a cold source circulation loop including the cold source module and the cold source pump.

[0017] Furthermore, a cold source recirculation solenoid valve is installed on the cold source branch pipe; a high-temperature impact solenoid valve is installed between the third and fifth connection points; a low-temperature impact solenoid valve is installed between the seventh connection point and the test piece; and an auxiliary solenoid valve is installed between the fourth and sixth connection points.

[0018] Furthermore, in both design schemes of the transition device, the liquid medium used in the heat source module, cold source module, and auxiliary cold source module is an aqueous solution of ethylene glycol. Of course, other liquids, such as alcohol, cold kerosene, methanol, etc., can also be used.

[0019] A method for in-situ testing of thermal shock cycles in a proton exchange membrane fuel cell, corresponding to the first design scheme of the transition device, is as follows:

[0020] A high-temperature impact circuit is used to perform a high-temperature impact on the test piece. A transition device is used to purge the high-temperature liquid inside the test piece and a portion of the heat source pipe to the heat source module. A low-temperature impact circuit is used to perform a low-temperature impact on the test piece. A transition device is used to purge the low-temperature liquid inside the test piece and a portion of the cold source pipe to the cold source module. This process is repeated.

[0021] A method for in-situ testing of thermal shock cycles in proton exchange membrane fuel cells, corresponding to the second design scheme of the transition device, is as follows:

[0022] The test piece is subjected to a high-temperature impact using a high-temperature impact circuit, cooled using a transition device, and then subjected to a low-temperature impact using a low-temperature impact circuit. This process is repeated.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) It can quickly switch between high and low temperatures in the internal environment of the fuel cell under test, and the response is rapid and without delay. This allows for efficient evaluation of the high and low temperature durability and lifespan of the materials and components in the stack. In addition, a transition module is added to keep the high and low temperature liquids of the entire test device stable for a long time.

[0025] (2) The transition module adopts the nitrogen purging technique to directly purge and remove the high-temperature liquid / low-temperature liquid, which can prevent the high-temperature liquid / low-temperature liquid remaining in the fuel cell stack and water cavity inlet / outlet pipes from mixing into the cold source / heat source, thereby avoiding the continuous rise of the liquid temperature in the cold source and the continuous drop of the liquid temperature in the heat source.

[0026] (3) Since heating is much easier than cooling, the transition module adopts the auxiliary cold source module technology route, which can cool down the fuel cell stack between high and low temperature impacts, thereby cooling down the fuel cell stack and pipelines, avoiding the continuous rise of liquid temperature in the cold source, and allowing high temperature impact to be carried out directly after low temperature impact, with less resource and energy consumption and lower experimental cost. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the present invention in Embodiment 1;

[0028] Figure 2 This is a schematic diagram of the high-temperature impact in Example 1;

[0029] Figure 3 This is a schematic diagram of the first purging in Example 1;

[0030] Figure 4 This is a schematic diagram of the low-temperature shock in Example 1;

[0031] Figure 5 This is a schematic diagram of the second purging in Example 1;

[0032] Figure 6 This is a schematic diagram of the structure of the present invention in Embodiment 2;

[0033] Figure 7 This is a schematic diagram of the high-temperature impact in Example 2;

[0034] Figure 8 This is a schematic diagram of the fuel cell stack cooling in Example 2;

[0035] Figure 9 This is a schematic diagram of the low-temperature shock in Example 2;

[0036] Figures 1-5 The accompanying figure labels are as follows:

[0037] 100. Fuel cell stack; 101. Fuel cell stack inlet; 102. Fuel cell stack outlet; 1. Heat source module; 2. Cold source module; 3. Heat source pump; 4. Cold source pump; 5. Nitrogen source; 6. Pressure regulating valve; 7-13. Check valve.

[0038] Figures 6-9 The accompanying figure labels are as follows:

[0039] 100. Fuel cell stack or test piece; 101. Water chamber inlet; 102. Water chamber outlet; 1. Heat source module; 2. Cold source module; 3. Heat source pump; 4. Cold source pump; 5. Auxiliary cold source module; 6. Transition valve; 7-10. Check valve. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0041] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, some components are appropriately exaggerated in the drawings.

[0042] In the description of the embodiments of this application, it should be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly placed when the product of this application is used, or the orientation or positional relationship commonly understood by those skilled in the art. They are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or component 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.

[0043] Furthermore, the terms "first," "second," and "third" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0044] In the description of the embodiments of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set," "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 of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0045] Example 1:

[0046] This application designs a heat source module 1 and a cold source module 2 to perform alternating thermal shocks, and also adds a transition module to prevent high-temperature liquid / low-temperature liquid from mixing into the cold source / heat source after high-temperature shock and low-temperature shock.

[0047] A proton exchange membrane fuel cell thermal shock cycle in-situ testing device includes a heat source module 1, a cold source module 2, and a transition module. The heat source module 1 is connected to the test piece 100 through a heat source pipe to form a high-temperature shock circuit. The cold source module 2 is connected to the test piece 100 through a cold source pipe to form a low-temperature shock circuit. The transition module is connected to the test piece 100 through a transition pipe.

[0048] In this embodiment, the transition device is a nitrogen source module, the heat source module 1 provides high-temperature liquid, and the cold source module 2 provides low-temperature liquid. The transition pipeline is divided into a first purging channel and a second purging channel. The nitrogen source module is connected to the test piece 100 and the heat source module 1 in sequence through the first purging channel, and the second purging channel is connected to the test piece 100 and the cold source module 2 in sequence. In this way, after a high-temperature impact / low-temperature impact, the transition device can be used to purge the high-temperature / low-temperature liquid inside the test piece 100 and in the water cavity inlet / outlet pipelines to the heat source module 1 / cold source module 2. When a low-temperature impact / high-temperature impact is performed again, there will be no situation where the high-temperature / low-temperature liquid mixes into the cold / heat source.

[0049] Specifically, such as Figure 1 As shown, the heat source pipeline is divided into a heat source inlet pipe and a heat source return pipe. A heat source pump 3 is installed on the heat source inlet pipe, which is a magnetic drive gear pump. Figure 1 In the GP-Ⅰ system, a heat source solenoid valve SV1 is installed on the heat source return pipe. The cold source pipeline is divided into a cold source inlet pipe and a cold source return pipe. A cold source pump 4 is installed on the cold source return pipe, which is a magnetic drive gear pump. Figure 1In the GP-II, the heat source pump 3 and the cold source pump 4 are magnetically driven gear pumps, whose starting and stopping speeds are controlled by external electrical signals and are only turned on when needed. A cold source solenoid valve SV2 is installed on the cold source return pipe. The first purge channel includes a first air inlet pipe and a heat source return pipe. A first connection point P1 is provided between the heat source pump 3 and the test piece 100. The two ends of the first air inlet pipe are connected to the nitrogen source module and the first connection point P1, respectively. The second purge channel includes a second air inlet pipe and a cold source return pipe. A second connection point P2 is provided between the cold source pump 4 and the test piece 100. The two ends of the second air inlet pipe are connected to the nitrogen source module and the second connection point P2, respectively. A first air inlet solenoid valve SV3 and a second air inlet solenoid valve SV4 are installed on the first air inlet pipe and the second air inlet pipe, respectively.

[0050] The nitrogen source module includes a nitrogen source 5 and a pressure regulating valve 6. The nitrogen source 5 provides the purging gas, and the pressure regulating valve 6 is used for pressure regulation, thereby adjusting the purging pressure. Multiple one-way valves are installed on the heat source pipeline, cold source pipeline, and transition pipeline, specifically, as follows... Figure 1 As shown, a one-way valve 7 is provided between the nitrogen source module and the first and second air inlet pipes; a one-way valve 8 is provided between the heat source pump 3 and the first connection point P1; a one-way valve 9 is provided between the first connection point P1 and the water chamber inlet 101; a one-way valve 10 is provided between the heat source solenoid valve SV1 and the heat source module 1; a one-way valve 11 is provided between the cold source pump 4 and the second connection point P2; a one-way valve 12 is provided between the second connection point P2 and the water chamber inlet 101; and a one-way valve 13 is provided between the cold source solenoid valve SV2 and the cold source module 2. The one-way valves are mainly used to ensure that the high / low temperature liquids can only flow in one direction and can prevent liquid backflow.

[0051] Understandable Figures 1-5 This embodiment only presents one feasible design scheme, including pipeline connection design, valve selection, and valve arrangement. In other embodiments, those skilled in the art can flexibly use different valves (such as adding a three-way valve), set branch pipes, merge pipelines, adjust the number and arrangement of valves, etc., to adjust the scheme. For example, one-way valves can be arranged on the first and second air intake pipes respectively to realize the technical solution of purging using nitrogen source 5 after high / low temperature impact. Further details are omitted here. It should also be noted that the positions and distances of components in the figure do not represent the actual scheme, but are only used to clearly illustrate the connection relationship between components and should not be construed as a limitation of this application.

[0052] The liquids for heat source module 1 and cold source module 2 can be aqueous solutions of ethylene glycol. Of course, other liquids such as alcohol, chilled kerosene, and methanol can also be used. For safety reasons and ease of access, it is recommended to use an aqueous solution of ethylene glycol with a volume concentration of approximately 52%, a freezing point < -40℃, and a boiling point > 100℃, which meets the requirements of all operating temperature ranges of the PEMFC.

[0053] In addition, depending on the testing requirements, filters, temperature sensors, pressure sensors, flow meters, and other sensors can be installed on the heat source pipes, cold source pipes, and transition pipes, as those skilled in the art will understand.

[0054] It is understandable that the heat source pump 3 and the cold source pump 4 can be controlled by external electrical signals to start, stop and speed. The heat source solenoid valve SV1, the cold source solenoid valve SV2, the first intake solenoid valve SV3 and the second intake solenoid valve SV4 can also be controlled by external electrical signals to start and stop. A controller can be set to control the above components and the thermal shock test can be controlled by the host computer.

[0055] When conducting in-situ thermal shock cycling tests on a proton exchange membrane fuel cell using the thermal shock cycling in-situ device provided in this embodiment, a cyclical approach of "high-temperature shock + purging + low-temperature shock + purging" is adopted. One cycle of "high-temperature shock + purging + low-temperature shock + purging" constitutes one high-low temperature cycle. Repeating this process allows for the testing of the fuel cell's high-low temperature cycle shock durability. Specifically, one cycle of "high-temperature shock + purging + low-temperature shock + purging" involves:

[0056] like Figure 2 As shown, during high-temperature shock, heat source pump 3 is turned on, cold source pump 4 is turned off, heat source solenoid valve SV1 is turned on, cold source solenoid valve SV2 is turned off, first intake solenoid valve SV3 and second intake solenoid valve SV4 are turned off, and high-temperature liquid in heat source module 1 enters the fuel cell stack through water cavity inlet 101 and then returns to heat source module 1 through water cavity outlet 102.

[0057] like Figure 3 As shown, during the first purging, the heat source pump 3 and the cold source pump 4 are shut down, the heat source solenoid valve SV1 and the cold source solenoid valve SV2 are shut down, the first intake solenoid valve SV3 is opened, and the second intake solenoid valve SV4 is closed. At this time, the high-temperature liquid inside the fuel cell stack and in the water chamber inlet / outlet pipes is purged back to the heat source module 1.

[0058] like Figure 4As shown, during cryogenic shock, heat source pump 3 is turned off, cold source pump 4 is turned on, heat source solenoid valve SV1 is turned off, cold source solenoid valve SV2 is turned on, first intake solenoid valve SV3 and second intake solenoid valve SV4 are turned off, and cryogenic liquid in cold source module 2 enters the fuel cell stack through water cavity inlet 101 and then returns to cold source module 2 through water cavity outlet 102.

[0059] like Figure 5 As shown, during the second purging, the heat source pump 3 and the cold source pump 4 are shut down, the heat source solenoid valve SV1 and the cold source solenoid valve SV2 are shut down, the first intake solenoid valve SV3 is shut down, and the second intake solenoid valve SV4 is opened. At this time, the cryogenic liquid inside the fuel cell stack and in the water chamber inlet / outlet pipes is purged back to the cold source module 2.

[0060] This application enables rapid switching between high and low temperatures of the internal environment of the fuel cell under test, with a fast and undelayed response, thereby allowing for efficient evaluation of the high and low temperature durability and lifespan of the materials and components within the stack.

[0061] The technical solution provided in this embodiment can subject the fuel cell under test to temperature alternation cycle shock within the range of -40℃ to 90℃. Nitrogen purging is added between the high and low temperature shocks to the fuel cell stack to prevent residual high temperature / low temperature liquid in the fuel cell stack and water chamber inlet / outlet pipes from mixing into the cold / heat source, thereby keeping the high and low temperature liquids of the entire test device at a stable temperature for a long time.

[0062] The main function of purging is to purge liquid into the heat source module 1 and the cold source module 2. However, purging cannot cause the temperature of the fuel cell stack water chamber and pipes to drop or rise rapidly. Therefore, inevitably, the low-temperature liquid will still cause the cold source to heat up to some extent after flowing through the high-temperature fuel cell stack and water chamber inlet / outlet pipes, and the high-temperature liquid will still cause the heat source to cool down to some extent after flowing through the low-temperature fuel cell stack and water chamber inlet / outlet pipes. However, by setting the low-temperature impact / high-temperature impact time, such as extending the high-temperature impact time, the temperature of the cold / heat source modules can be stabilized at the set value for a longer period of time. Compared with the solution without a transition module, the transition module added in this embodiment plays a very good role in maintaining the temperature stability of the heat source / cold source.

[0063] Example 2:

[0064] In Example 1, a nitrogen source module was selected as the transition device, and a corresponding pipeline design was implemented to connect the test piece 100, the cold source module 2, and the heat source module 1. This prevented the high-temperature / low-temperature liquid from mixing into the cold / heat source through liquid purging. However, after the high-temperature impact on the fuel cell stack, only nitrogen purging was performed on the stack. The internal parts of the stack and the inlet / outlet pipes of the water cavity remained at a high temperature. When the low-temperature impact was then performed, the low-temperature liquid flowed through the stack and the inlet / outlet of the water cavity and returned to the cold source, inevitably causing the cold source temperature to rise. Although extending the high-temperature impact time could allow the cold source module to obtain more cooling time, practice has shown that it is difficult to keep the cold source liquid below -35°C for a long time. Therefore, the solution in Example 1 is suitable for experimental applications at low temperatures above -35°C to 100°C for long periods (more than one month or more than 100,000 cold / heat cycles). In this solution, the high / low temperature impact circuit and the nitrogen purging circuit are independent of each other and are not affected by each other. The system is stable and reliable and suitable for long-term high and low temperature cyclic impact tests. For high and low temperature cycles below -35°C, such as -40 / 90°C, the scheme in Example 1 is not recommended.

[0065] Based on this, the applicant proposed a transition device design scheme that differs from Embodiment 1.

[0066] A proton exchange membrane fuel cell thermal shock cycle in-situ testing device includes a heat source module 1, a cold source module 2, and a transition module. The heat source module 1 is connected to the test piece 100 through a heat source pipe to form a high-temperature shock circuit. The cold source module 2 is connected to the test piece 100 through a cold source pipe to form a low-temperature shock circuit. The transition module is connected to the test piece 100 through a transition pipe.

[0067] In this embodiment, the transition device is an auxiliary cold source module 5. The heat source module 1 provides high-temperature liquid, the cold source module 2 provides low-temperature liquid, and the auxiliary cold source module 5 provides low-temperature liquid. The transition module is connected to the test piece 100 via a transition pipe to form a transition loop. The transition pipe is divided into a transition inlet pipe and a transition return pipe, and a transition pump 6 is installed on the transition inlet pipe. The transition pump 6 is a magnetically driven gear pump, i.e. Figure 6 In the middle GP, the transition pump 6 is controlled by an external electrical signal to start, stop and speed, and is only turned on when needed. The heat source pump 3 and cold source pump 4 are ordinary water pumps that work continuously after the power is connected without start-stop control, thereby reducing the control complexity and cost of the entire system and helping to improve the stability and reliability of the entire system operation.

[0068] In this embodiment, the transition scheme uses an auxiliary cold source module. After a high-temperature impact, the transition device can remove the residual high-temperature liquid inside the test piece 100 and in the inlet / outlet pipes of the water cavity, simultaneously lowering the temperature inside the test piece 100 and the inlet / outlet pipes of the water cavity. Therefore, during a low-temperature impact, there will be no rapid temperature rise of the low-temperature liquid in the cold source, allowing the cold source module to remain stable at the ideal ultra-low temperature. Since heating is much easier than cooling, a high-temperature impact can be performed directly after the low-temperature impact. This can be achieved by appropriately extending the low-temperature impact time or setting the heat source temperature approximately 5°C higher than the target temperature, ensuring that the hydrothermal liquid temperature during the high-temperature impact does not fall below the target value. Alternatively, an auxiliary heat source module could be added to the transition module to heat the fuel cell stack after the low-temperature impact, but this would increase cost and the overall system control complexity. Therefore, those skilled in the art should weigh the options carefully as needed.

[0069] The liquids for the heat source module 1, cold source module 2, and auxiliary cold source module 5 can be aqueous solutions of ethylene glycol. Of course, other liquids such as alcohol, chilled kerosene, and methanol can also be used. For safety reasons and ease of access, it is recommended to use an aqueous solution of ethylene glycol with a volume concentration of approximately 52%, a freezing point < -40℃, and a boiling point > 100℃, which meets the requirements of all operating temperature ranges of the PEMFC.

[0070] Specifically, such as Figure 6 As shown, the heat source pipeline is divided into a heat source inlet pipe and a heat source return pipe. A heat source pump 3 is installed on the heat source inlet pipe, which is a water pump. Figure 6 In section M-Ⅰ, a heat source solenoid valve SV6 is installed on the heat source return pipe. The cold source pipeline is divided into a cold source inlet pipe and a cold source return pipe. A cold source pump 4 is installed on the cold source return pipe; a water pump is selected. Figure 6 In the M-II system, the heat source pump 3 and the cold source pump 4 are not controlled by external electrical signals to start or stop, and the system continues to work after being powered on; a cold source solenoid valve SV5 is installed on the cold source return pipe; a third connection point P3 is provided between the heat source pump 3 and the test piece 100; the two ends of the transition inlet pipe are respectively connected to the auxiliary cold source module 5 and the third connection point P3; a fourth connection point P4 is provided between the heat source solenoid valve SV6 and the heat source module 1; the two ends of the transition return pipe are respectively connected to the auxiliary cold source module 5 and the fourth connection point P4; and a transition return solenoid valve SV8 is installed on the transition return pipe.

[0071] It also includes a heat source branch pipe and a cold source branch pipe. A fifth connection point P5 is provided between the heat source pump 3 and the third connection point P3, and a sixth connection point P6 is provided between the heat source module 1 and the fourth connection point. The two ends of the heat source branch pipe are connected to the fifth connection point P5 and the sixth connection point P6 respectively, forming a heat source circulation loop including the heat source module 1 and the heat source pump 3. A heat source circulation solenoid valve SV4 is provided on the heat source branch pipe. A seventh connection point P7 is provided between the cold source pump 4 and the test piece 100. A cold source solenoid valve is provided between the cold source module 2 and the cold source module 2. An eighth connection point P8 is provided. The two ends of the cold source branch pipe are connected to the seventh connection point P7 and the eighth connection point P8 respectively, forming a cold source circulation loop including the cold source module 2 and the cold source pump 4. A cold source circulation solenoid valve SV3 is provided on the cold source branch pipe. A high temperature impact solenoid valve SV1 is provided between the third connection point P3 and the fifth connection point P5. A low temperature impact solenoid valve SV2 is provided between the seventh connection point P7 and the test piece 100. An auxiliary solenoid valve SV7 is provided between the fourth connection point P4 and the sixth connection point.

[0072] This embodiment is designed with heat source branch pipes and cold source branch pipes, so that heat source module 1 and cold source module 2 can have separate small circulation when they are not flowing through the fuel cell stack. This can alleviate the working pressure of heat source pump 3 and cold source pump 4, so that when they are subjected to high temperature / low temperature shocks, cold source pump 4 / heat source pump 3 will not have pressure build-up, thereby extending their service life and improving the stability of the entire system device.

[0073] Multiple check valves are installed on the heat source pipeline, cold source pipeline, and transition pipeline. Specifically, for example... Figure 6 As shown, a one-way valve 7 is provided between the third connection point P3 and the water chamber inlet 101, a one-way valve 8 is provided between the seventh connection point P7 and the water chamber inlet 101, a one-way valve 9 is provided between the cold source solenoid valve and the eighth connection point P8, and a one-way valve 10 is provided between the transition pump 6 and the third connection point P3. The one-way valves are mainly used to ensure that the high / low temperature liquids can only flow in one direction and can prevent liquid backflow.

[0074] Understandable Figures 6-9 This embodiment only presents one feasible design scheme, including pipeline connection design, valve selection, and valve arrangement. In other embodiments, those skilled in the art can flexibly use different valves (such as adding a three-way valve), set branch pipes, merge pipelines, adjust the number and arrangement of valves, etc., to adjust the scheme, such as adjusting the number of check valves, to achieve the technical solution of using nitrogen source 5 for cooling after high-temperature impact. Further details are omitted here. It should also be noted that the positions and distances of components in the figure do not represent the actual scheme, but are only used to clearly illustrate the connection relationships between components and should not be construed as limiting this application.

[0075] In addition, depending on the testing requirements, filters, temperature sensors, pressure sensors, flow meters, and other sensors can be installed on the heat source pipes, cold source pipes, and transition pipes, as those skilled in the art will understand.

[0076] Understandably, heat source pump 3 and cold source pump 4 are not controlled by external electrical signals to start or stop; they operate continuously after the system is powered on. Transition pump 6, however, can be controlled by external electrical signals to start, stop, and adjust its speed. This arrangement aims to reduce the control complexity and cost of the entire system, while improving its stability and reliability. The high-temperature shock solenoid valve SV1, low-temperature shock solenoid valve SV2, cold source self-circulation solenoid valve SV3, heat source self-circulation solenoid valve SV4, cold source solenoid valve SV5, heat source solenoid valve SV6, auxiliary solenoid valve SV7, and transition return solenoid valve SV8 can all be controlled by external electrical signals. A controller can be installed to manage these components, allowing for thermal shock testing controlled by a host computer.

[0077] When conducting in-situ thermal shock cycling tests on a proton exchange membrane fuel cell using the thermal shock cycling in-situ device provided in this embodiment, a cyclical approach of "high-temperature shock + water-cooled stack + low-temperature shock" is adopted. One cycle of "high-temperature shock + water-cooled stack + low-temperature shock" constitutes one high-low temperature cycle. Repeating this process allows for the testing of the fuel cell's high-low temperature cycle shock durability. Specifically, one cycle of "high-temperature shock + water-cooled stack + low-temperature shock" involves:

[0078] After the system is powered on, heat pump 3 and cold pump 4 are connected to the power supply and continue to work.

[0079] like Figure 7 As shown, during high-temperature shock, the transition pump 6 is closed, the high-temperature shock solenoid valve SV1 is open, the low-temperature shock solenoid valve SV2 is closed, the cold source recirculation solenoid valve SV3 is open, the heat source recirculation solenoid valve SV4 is closed, the cold source solenoid valve SV5 is closed, the heat source solenoid valve SV6 is open, the auxiliary solenoid valve SV7 is open, and the transition return solenoid valve SV8 is closed. The high-temperature liquid in the heat source module 1 enters the fuel cell stack through the water chamber inlet 101 and then returns to the heat source module 1 through the water chamber outlet 102. The cold source module 2 performs a small circulation, and the low-temperature liquid in the cold source module 2 flows back to the cold source module 2 through the cold source recirculation solenoid valve SV3. The transition circuit where the auxiliary cold source module 5 is located is not working.

[0080] like Figure 8As shown, during the water-cooled fuel cell stack operation, the transition pump 6 is activated, the high-temperature impact solenoid valve SV1 is closed, the low-temperature impact solenoid valve SV2 is closed, the cold source recirculation solenoid valve SV3 is open, the heat source recirculation solenoid valve SV4 is open, the cold source solenoid valve SV5 is closed, the heat source solenoid valve SV6 is open, the auxiliary solenoid valve SV7 is closed, and the transition return solenoid valve SV8 is open. The low-temperature liquid in the auxiliary cold source module 5 enters the fuel cell stack through the water chamber inlet 101 and then returns to the auxiliary cold source module 5 through the water chamber outlet 102. The heat source module 1 undergoes a small circulation, and the high-temperature liquid in the heat source module 1 flows through the heat source recirculation solenoid valve SV4 back to the heat source module 1. The cold source module 2 undergoes a small circulation, and the low-temperature liquid in the cold source module 2 flows through the cold source recirculation solenoid valve SV3 back to the cold source module 2.

[0081] like Figure 9 As shown, during cryogenic shock, the transition pump 6 is closed, the high-temperature shock solenoid valve SV1 is closed, the cryogenic shock solenoid valve SV2 is open, the cold source recirculation solenoid valve SV3 is closed, the heat source recirculation solenoid valve SV4 is open, the cold source solenoid valve SV5 is open, the heat source solenoid valve SV6 is closed, the auxiliary solenoid valve SV7 is closed, and the transition return solenoid valve SV8 is closed. The high-temperature liquid in the cold source module 2 enters the fuel cell stack through the water chamber inlet 101 and then returns to the cold source module 2 through the water chamber outlet 102. The heat source module 1 performs a small circulation, and the high-temperature liquid in the heat source module 1 flows through the heat source recirculation solenoid valve SV4 to return to the heat source module 1. The transition circuit where the auxiliary cold source module 5 is located is not working.

[0082] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A test method for an in-situ testing device for thermal shock cycles of a proton exchange membrane fuel cell, characterized in that, The testing device includes a heat source module, a cold source module, and a transition module. The heat source module is connected to the test piece via a heat source pipe to form a high-temperature impact circuit. The cold source module is connected to the test piece via a cold source pipe to form a low-temperature impact circuit. The transition module is connected to the test piece via a transition pipe. Multiple one-way valves are installed on the heat source pipe, cold source pipe, and transition pipe. The heat source pipe is divided into a heat source inlet pipe and a heat source return pipe, with a heat source pump installed on the heat source inlet pipe and a heat source solenoid valve installed on the heat source return pipe. The cold source pipe is divided into a cold source inlet pipe and a cold source return pipe, with a cold source pump installed on the cold source return pipe and a cold source solenoid valve installed on the cold source return pipe. The transition module is an auxiliary cold source module. The transition module is connected to the test piece through a transition pipe to form a transition loop. The transition pipe is divided into a transition inlet pipe and a transition return pipe. A transition pump is installed on the transition inlet pipe. The transition pump is a magnetic drive gear pump. The heat source pump and the cold source pump are water pumps. A third connection point is provided between the heat source pump and the test piece. The two ends of the transition liquid inlet pipe are respectively connected to the auxiliary cold source module and the third connection point. A fourth connection point is provided between the heat source solenoid valve and the heat source module. The two ends of the transition liquid return pipe are respectively connected to the auxiliary cold source module and the fourth connection point. A transition liquid return solenoid valve is provided on the transition liquid return pipe. The testing method includes: The test piece is subjected to a high-temperature impact using a high-temperature impact circuit, cooled using a transition device, and then subjected to a low-temperature impact using a low-temperature impact circuit. This process is repeated.

2. The test method of the in-situ testing device for thermal shock cycling of a proton exchange membrane fuel cell according to claim 1, characterized in that, The testing device also includes a heat source branch pipe and a cold source branch pipe. A fifth connection point is provided between the heat source pump and the third connection point, and a sixth connection point is provided between the heat source module and the fourth connection point. The two ends of the heat source branch pipe are respectively connected to the fifth connection point and the sixth connection point to form a heat source circulation loop including the heat source module and the heat source pump. A heat source circulation solenoid valve is provided on the heat source branch pipe. A seventh connection point is provided between the cold source pump and the test piece, and an eighth connection point is provided between the cold source solenoid valve and the cold source module. The two ends of the cold source branch pipe are respectively connected to the seventh connection point and the eighth connection point to form a cold source circulation loop including the cold source module and the cold source pump.

3. The test method of the in-situ testing device for thermal shock cycling of a proton exchange membrane fuel cell according to claim 2, characterized in that, A cold source self-circulation solenoid valve is installed on the cold source branch pipe; a high-temperature impact solenoid valve is installed between the third and fifth connection points; a low-temperature impact solenoid valve is installed between the seventh connection point and the test piece; and an auxiliary solenoid valve is installed between the fourth and sixth connection points.

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