An integrated fuel cell stack assembly with activation function and method

Abstract

The application discloses an integrated electric pile clamping device with activation function, which comprises a clamping table, a lower tool plate, an upper tool plate, a fuel cell electric pile, an external power source, an air inlet device, an air outlet device and a pressing device; the lower tool plate is fixed on the clamping table, the fuel cell electric pile is installed on the lower tool plate, the positive and negative poles of the fuel cell electric pile are connected with the external power source through wires respectively, and the top of the fuel cell electric pile is provided with the upper tool plate; a vertical air inlet channel is formed in one side of the fuel cell electric pile; and a vertical air outlet channel is formed in the other side of the fuel cell electric pile. The application has the beneficial effects that the fuel cell electric pile assembling, leakage detection and activation are integrated on the same device, the hydrogen pump can be used for activation after the leakage detection, the electric pile activation time can be effectively reduced, the additional fuel consumption and waste can be reduced, the time consumed by the transfer between multiple devices of the electric pile can be reduced, and the batch production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and specifically to an integrated fuel cell stack clamping device and method with activation function. Background Technology

[0002] A proton exchange membrane fuel cell is an energy conversion device that can directly convert the chemical energy in hydrogen into electrical energy. It has advantages such as high power density, fast start-up speed, high conversion efficiency, environmental friendliness, readily available raw materials, and clean and efficient operation, and has broad application prospects in the field of new energy vehicles.

[0003] Before fuel cell stacks can be put into formal operation, their normal operating conditions and safety during operation must be ensured. Therefore, an airtightness check is required after the stack is assembled. After assembly, the stack is transported to a leak detection device for airtightness testing. If the airtightness fails to meet the requirements, the stack is returned to the assembly device for disassembly and reassembly, which reduces stack assembly efficiency. The electrochemical activity of the stack is very low during initial operation, so activation treatment is necessary beforehand. The traditional method is to continuously discharge the stack under a constant high current, a process that often takes a long time, typically 12 to 48 hours. Both leak detection and activation significantly impact the production efficiency of assembling the stack for formal operation. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing an integrated fuel cell stack clamping device with activation function that is time-efficient and has high production efficiency.

[0005] The technical solution adopted in this invention is as follows: an integrated fuel cell stack clamping device with activation function, including a clamping platform, a lower tooling plate, an upper tooling plate, a fuel cell stack, an external power supply, an air inlet device, an air outlet device, and a clamping device; the lower tooling plate is fixed on the clamping platform, the fuel cell stack is mounted on the lower tooling plate, the positive and negative electrodes of the fuel cell stack are respectively connected to the external power supply through wires, the upper tooling plate is provided on the top of the fuel cell stack, and the clamping device is arranged on the top of the upper tooling plate; an air inlet pipe is opened in the upper tooling plate, and the inlet of the air inlet pipe is connected to the air inlet device; a vertical air inlet channel is opened on one side of the fuel cell stack, and the upper inlet of the air inlet channel is connected to the outlet of the air inlet pipe; a vertical air outlet channel is opened on the other side of the fuel cell stack, and the lower outlet of the air outlet channel is connected to the inlet of the air outlet pipe opened in the lower tooling plate, and the outlet of the air outlet pipe is connected to the air outlet device.

[0006] According to the above scheme, three sets of air intake channels are opened on one side of the fuel cell stack, namely a hydrogen air intake channel, an air intake channel, and a cooling water air intake channel. Each set of air intake channels is configured with an air intake pipe, that is, three air intake pipes are opened on the upper tooling plate, and the air intake pipes are connected to the air intake device. Three sets of air outlet channels are opened on the other side of the fuel cell stack, namely a hydrogen air outlet channel, an air outlet channel, and a cooling water air outlet channel. Each set of air outlet channels is configured with an air outlet pipe, that is, three air outlet pipes are opened on the lower tooling plate, and each air outlet pipe is connected to the corresponding air outlet device. The air intake channel and the air outlet channel together form an air channel, the hydrogen intake channel and the hydrogen outlet channel together form a hydrogen channel, and the cooling water intake channel and the cooling water outlet channel together form a cooling water channel.

[0007] According to the above scheme, the fuel cell stack includes, from bottom to top, a first end plate, a first insulating plate, a first current collector, a core composed of alternating stacks of multiple bipolar plates and membrane electrode assemblies, a second current collector, a second insulating plate, and a second end plate; the first end plate is disposed on a lower tooling plate; the second end plate is topped with an upper tooling plate, and a sealing ring is provided between the two; the first current collector is a cathode current collector, connected to the negative terminal of an external power supply via a wire, and the second current collector is an anode current collector, connected to the positive terminal of an external power supply via a wire; the first end plate, the first insulating plate, and the first... The stack core and the manifold are each provided with three sets of gas outlet channels that are perpendicularly connected to the gas outlet pipes. These are hydrogen gas outlet channels, air gas outlet channels, and cooling water gas outlet channels. The stack core, the second manifold, the second insulating plate, and the second end plate are each provided with three sets of gas outlet channels that are perpendicularly connected to the gas inlet pipes. These are hydrogen gas inlet channels, air inlet channels, and cooling water inlet channels. The three sets of gas inlet channels and the three sets of gas outlet channels are located on both sides of the fuel cell stack. The gas entering through each gas inlet channel can flow laterally within the stack core to the corresponding gas outlet channel and be discharged through the corresponding gas outlet pipes and gas outlet devices.

[0008] According to the above scheme, the air outlet device includes an air outlet pipe, and an outlet temperature and pressure sensor and an outlet solenoid valve installed on the air outlet pipe; one end of the air outlet pipe is connected to the outlet of the air outlet pipeline; the outlet temperature and pressure sensor is used to detect the temperature and pressure of the air outlet pipe.

[0009] According to the above scheme, the air intake device includes a first air intake pipe and a second air intake pipe. One end of the first air intake pipe is connected to the air intake channel and the cooling water intake channel through two branch pipes and corresponding air intake pipes, respectively. Temperature and pressure sensors and inlet solenoid valves are respectively installed on the two branch pipes. The other end of the first air intake pipe is connected to a nitrogen cylinder. A flow meter, a pressure regulating valve a and a pressure reducing valve are also installed on the first air intake pipe in sequence.

[0010] According to the above scheme, one end of the second intake pipe is connected to the hydrogen intake channel through a corresponding intake pipe, and the other end of the second intake pipe is connected to the hydrogen cylinder. The second intake pipe is sequentially equipped with an inlet temperature and pressure sensor, an inlet solenoid valve d, a pressure regulating valve b, and a pressure reducing valve. The first intake pipe and the second intake pipe are connected by a bypass pipe, and an inlet solenoid valve c is installed on the bypass pipe.

[0011] The present invention also discloses a leak detection and activation method based on the above-described fuel cell stack clamping device, comprising the following steps:

[0012] Step 1: Prepare the fuel cell stack and install the entire fuel cell stack between the upper and lower tooling plates of the clamping table. Apply a set force to the fuel cell stack using a clamping device to bring the fuel cell stack to the designed fastening height.

[0013] Step 2: Perform leak tests on the hydrogen passage, air passage, and cooling water passage of the fuel cell stack.

[0014] Step 3: Open or close the corresponding valves according to the hydrogen pump activation principle, and activate the fuel cell stack according to the specified test conditions;

[0015] Step 4: Securely assemble the activated fuel cell stack.

[0016] According to the above scheme, in step two, the specific leak detection method is as follows: close all solenoid valves of the outlet and inlet devices, adjust the pressure regulating valve to the leak detection pressure, open the pressure regulating valve a of the inlet device to allow nitrogen to enter the fuel cell stack and maintain constant pressure, observe the flow meter value until the flow count value remains stable and record the leakage flow of the air channel; in the same way, by closing other solenoid valves, open the corresponding nitrogen gas to flow into the cooling water channel, hydrogen channel and air channel respectively, record the gas leakage of the corresponding cooling water channel, air channel and hydrogen channel under constant pressure. If the detected leakage value is ≤ the number of stacked membrane electrode assemblies of the fuel cell stack × 1.0, the airtightness of the fuel cell stack can be judged to be qualified.

[0017] According to the above scheme, the leak detection pressure is 50-150 kPaG.

[0018] According to the above scheme, the specified test conditions for activation are as follows: the current applied for stack activation is (0.5~1.5A·cm). -2 () × active area; nitrogen supply flow rate is twice the metering ratio of the corresponding fuel cell stack activation current, hydrogen supply flow rate is twice the metering ratio of the corresponding fuel cell stack activation current; activation time is 5-10 min.

[0019] The beneficial effects of this invention are as follows: This invention integrates the assembly, leak detection, and activation of fuel cell stacks into the same device. After leak detection, activation can be performed via a hydrogen pump, which can effectively reduce the stack activation time, reduce additional fuel consumption and waste, and also reduce the time spent on transferring multiple devices of the stack, thereby improving the efficiency of mass production and increasing production capacity. This invention also allows for direct leak detection and activation after assembly, avoiding the need for repeated disassembly and reassembly of the stack due to unqualified airtightness testing after assembly or unqualified performance after activation, which wastes time. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of a specific embodiment of the present invention.

[0021] Figure 2 For the present invention Figure 1 Vertical section view of AA.

[0022] Figure 3 For the present invention Figure 1 Vertical cross-section view of B1-B1 (structural schematic diagram of the anode plate side).

[0023] Figure 4 For the present invention Figure 1 Vertical cross-section view of B2-B2 (schematic diagram of the cathode plate side).

[0024] Figure 5 For the present invention Figure 1 Vertical cross-section of the CC section.

[0025] Figure 6 This is a schematic diagram of a fuel cell stack clamping device with leak detection and activation functions applied to U-shaped fuel cell stack assembly according to the present invention.

[0026] Figure 7 The graphs show the performance test curves of the stack current density and average voltage in this embodiment, including the unactivated, conventionally activated, and hydrogen pump activated stacks.

[0027] Wherein: 1-Clamping platform; 2-Lower tooling plate; 3-Upper tooling plate; 4-Electric stack; 5-Inlet device; 6-Outlet device; 7-First end plate; 8-First insulating plate; 9-First current collector plate; 10-Core; 11-Second current collector plate; 12-Second insulating plate; 13-Second end plate; 14-External power supply; 15-Outlet temperature / pressure sensor; 16-Outlet solenoid valve; 17-Inlet / outlet temperature / pressure sensor; 18-Inlet solenoid valve; 19-Flow meter; 2 0-Pressure regulating valve; 21-Pressure reducing valve; 22-Gas cylinder; 23-Pressure clamping device; 24-Inlet solenoid valve a; 25-Inlet solenoid valve b; 26-Inlet solenoid valve c; 27-Inlet solenoid valve d; 28-Outlet solenoid valve e; 29-Outlet solenoid valve f; 30-Outlet solenoid valve g; 31-Nitrogen cylinder; 32-Hydrogen cylinder; 33-Pressure regulating valve a; 34-Pressure regulating valve b; 35-Anode plate; 36-Cathode plate; 37-First inlet pipe; 38-Second inlet pipe. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figure 1 An integrated fuel cell stack clamping device with activation function is shown, comprising a clamping platform 1, a lower tooling plate 2, an upper tooling plate 3, a fuel cell stack 4, an external power supply 14, an air inlet device 5, an air outlet device 6, and a clamping device 23. The lower tooling plate 2 is fixed on the clamping platform 1, and the fuel cell stack 4 is mounted on the lower tooling plate 2. The positive and negative terminals of the fuel cell stack 4 are connected to the external power supply 14 via wires. The upper tooling plate 3 is located on the top of the fuel cell stack 4, and the clamping device 23 is mounted on the top of the upper tooling plate 3. An air inlet pipe is provided in the upper tooling plate 3, and the inlet of the air inlet pipe is connected to the air inlet device 5. A vertical air inlet channel is provided on one side of the fuel cell stack 4, and the upper inlet of the air inlet channel is connected to the outlet of the air inlet pipe. A vertical air outlet channel is provided on the other side of the fuel cell stack 4, and the lower outlet of the air outlet channel is connected to the inlet of the air outlet pipe located in the lower tooling plate 2. The outlet of the air outlet pipe is connected to the air outlet device 6.

[0030] In this invention, the fuel cell stack 4 has three sets of air inlet channels on one side: a hydrogen inlet channel, an air inlet channel, and a cooling water inlet channel. Each set of air inlet channels corresponds to an air inlet pipe, meaning the upper tooling plate has three air inlet pipes connected to the air inlet device. The fuel cell stack 4 also has three sets of air outlet channels on the other side: a hydrogen outlet channel, an air outlet channel, and a cooling water outlet channel. Each set of air outlet channels corresponds to an air outlet pipe, meaning the lower tooling plate has three air outlet pipes, each connected to a corresponding air outlet device. In this invention, the air inlet channel and the air outlet channel together constitute an air channel, the hydrogen inlet channel and the hydrogen outlet channel together constitute a hydrogen channel, and the cooling water inlet channel and the cooling water outlet channel together constitute a cooling water channel.

[0031] Preferably, the fuel cell stack 4 includes, from bottom to top, a first end plate 7, a first insulating plate 8, a first current collector 9, a core 10 composed of alternating stacks of multiple bipolar plates and membrane electrode assemblies, a second current collector 11, a second insulating plate 12, and a second end plate 13; the first end plate 7 is disposed on the lower tooling plate 2, and the side of the first end plate 7 of the fuel cell stack 4 near the lower tooling plate 2 has a sealing ring groove, in which a matching silicone rubber sealing ring is installed to seal between the first end plate 7 and the lower tooling plate 2; the second end plate 13 is topped with an upper tooling plate 3, and a sealing ring is provided between the two for sealing; the first current collector 9 is a cathode current collector and is connected to the negative terminal of an external power supply 14 via a wire, and the second current collector 11 is an anode current collector and is connected to the positive terminal of the external power supply 14 via a wire. The first end plate 7, the first insulating plate 8, the first current collector 9, and the core 10 are each provided with three sets of gas outlet channels that are perpendicularly connected to the gas outlet pipeline, namely a hydrogen gas outlet channel, an air gas outlet channel, and a cooling water gas outlet channel; the core 10, the second current collector 11, the second insulating plate 12, and the second end plate 13 are each provided with three sets of gas outlet channels that are perpendicularly connected to the gas inlet pipeline, namely a hydrogen gas inlet channel, an air gas inlet channel, and a cooling water gas inlet channel. The three sets of inlet channels and the three sets of outlet channels are located on both sides of the fuel cell stack 4; the gas entering through each inlet channel can flow laterally within the core 10 to the corresponding outlet channel (e.g., hydrogen flowing in through the hydrogen gas inlet channel flows laterally within the core 10 to the hydrogen gas outlet channel), and is finally discharged through the corresponding outlet pipeline and outlet device.

[0032] Preferably, the air outlet device 6 includes an air outlet pipe, and an outlet temperature and pressure sensor 15 and an outlet solenoid valve 16 installed on the air outlet pipe; one end of the air outlet pipe is connected to the outlet of the air outlet pipeline; the outlet temperature and pressure sensor 15 is used to detect the temperature and pressure of the air outlet pipe. Figure 2As shown, the three outlet pipes of the three sets of air outlet devices are respectively equipped with outlet solenoid valves a28, b29 and c30.

[0033] In this invention, the air intake device 5 includes a first air intake pipe 37 and a second air intake pipe 38. One end of the first air intake pipe 37 is connected to an air intake channel and a cooling water intake channel via two branch pipes, respectively, through corresponding air intake pipes. Temperature and pressure sensors and inlet solenoid valves 18 (specifically, inlet solenoid valves a24 and b25) are respectively installed on the two branch pipes. The other end of the first air intake pipe is connected to a nitrogen cylinder 31. A flow meter 19, a pressure regulating valve a33, and a pressure reducing valve 21 are also sequentially installed on the first air intake pipe. One end of the second air intake pipe 38 is connected to a hydrogen intake channel via a corresponding air intake pipe, and the other end of the second air intake pipe 38 is connected to a hydrogen cylinder. An inlet temperature and pressure sensor 17, an inlet solenoid valve d27, a pressure regulating valve b34, and a pressure reducing valve 21 are sequentially installed on the second air intake pipe 38. The first air intake pipe 37 and the second air intake pipe 38 are connected by a bypass pipe, and an inlet solenoid valve c26 is installed on the bypass pipe.

[0034] In this invention, Figure 1 The imported solenoid valve 18 includes imported solenoid valve a24, imported solenoid valve b25, imported solenoid valve c26 and imported solenoid valve d27. Figure 1 The pressure regulating valve 20 includes pressure regulating valve a33 and pressure regulating valve b34; Figure 1 The gas cylinder 22 includes a nitrogen cylinder 31 and a hydrogen cylinder 32. Inlet solenoid valves a24, b25, and c26 control the supply of nitrogen to the air intake channel, cooling water intake channel, and hydrogen intake channel of the fuel cell stack 4, respectively; inlet solenoid valve d27 controls the supply of hydrogen to the hydrogen intake channel. Pressure regulating valve 20 consists of two valves: pressure regulating valve a33 regulates the nitrogen pressure, and pressure regulating valve b33 regulates the hydrogen pressure. The outlet solenoid valve of the outlet device 16 consists of three valves: outlet solenoid valves e28, f29, and g30 control the opening and closing of the hydrogen outlet channel, cooling water outlet channel, and air outlet channel of the fuel cell stack 4, respectively.

[0035] Figure 2 This is a cross-sectional view of the air intake pipe design on the upper tooling plate 3. The gas is controlled by the inlet solenoid valve 18 and pressure regulating valve 20 in the air intake device 5 to enter the holes corresponding to the hydrogen intake pipe, cooling water intake pipe, and air intake pipe on the side of the upper tooling plate 3, and then vertically enters the hydrogen intake channel, cooling water intake channel, and air intake channel of the fuel cell stack 4. In this invention, the bipolar plate 10 is composed of a cathode plate 35 and an anode plate 36. Figure 3This is a cross-sectional view of the anode plate 35 of the fuel cell stack 4. The gas entering the hydrogen inlet channel of the fuel cell stack 4 flows out through the flow channel of the anode plate 35 from another port of the anode plate 35 (that is, from the hydrogen outlet channel of the anode plate 35). Figure 4 This is a cross-sectional view of the cathode plate 36 of the fuel cell stack. The gas entering the air intake channel of the fuel cell stack 4 flows out through the flow channel of the cathode plate 36 from another port of the cathode plate 36 (that is, the air outlet channel of the cathode plate 36). The gas flowing into the cooling water intake channel also flows in the same way. Figure 5 This is a cross-sectional view of the air inlet design of the lower tooling plate 2. The gas flowing out from the flow channels of the anode plate 35 and the cathode plate 36 is discharged through the air outlet pipe designed in the lower tooling plate 2, and then flows horizontally into the air outlet device 6. The gas discharge is controlled by the solenoid valve 16 of the air outlet device 6.

[0036] like Figure 6 As shown, when the present invention is applied to a U-shaped fuel cell stack, the air intake device 5 and the air outlet device 6 can be integrated on the lower tooling plate 2 according to the specific structure of the U-shaped fuel cell stack 4. Multiple air intake pipes and multiple air outlet pipes are opened in the lower tooling plate 2.

[0037] In this embodiment, the clamping platform 1 serves as an assembly table for other components, providing planar space and positioning holes for functions such as fuel cell stack assembly, leak detection, and activation. The lower tooling plate 2 is located on and fixed to the clamping platform 1. Hydrogen, air, and cooling water pipes are also arranged on the lower tooling plate 2 on its projection plane perpendicular to the gas outlet channel of the fuel cell stack 4, and are connected to the side gas outlet device through a hole inside the lower tooling plate 2. The gas outlet device 6 at the lower tooling plate 2 is located near the hole in the lower tooling plate 2 and includes gas outlet pipes sequentially connected to the lower tooling plate 2. The upper tooling plate 3 is located on the fuel cell stack 4 and is mounted on the second end plate of the fuel cell stack 4 via positioning pins. The hydrogen, air, and cooling water inlet pipes correspond to the second end plate 13. The external power supply 14 provides the current required for the activation of the fuel cell stack 4. The two ends of the external power supply 14 are connected to the upper and lower current collectors of the fuel cell stack 4 via cables. The anode of the fuel cell stack 4 is connected to the negative terminal of the external power supply 14, and the cathode of the fuel cell stack 4 is connected to the positive terminal of the external power supply 14. The clamping device 23 provides clamping force for the assembly of the fuel cell stack 4. In the fuel cell stack 4, the number of stacked cores 10 is related to the stroke of the clamping platform 1 during clamping.

[0038] A leak detection and activation method based on the above-mentioned fuel cell stack clamping device includes the following steps:

[0039] Step 1: Prepare the fuel cell stack 4 and install the fuel cell stack 4 as a whole between the upper tooling plate 3 and the lower tooling plate 2 of the clamping table 1. Apply a set force to the fuel cell stack 4 through the clamping device to make the fuel cell stack 4 reach the designed fastening height.

[0040] The fuel cell stack 4 includes a first end plate 7, a first insulating plate 8, a first current collector 9, a stack core 10 formed by alternating stacks of multiple bipolar plates and membrane electrode assemblies, a second current collector 11, a second insulating plate 12, and a second end plate 13. After the fuel cell stack 4 is installed on the lower tooling plate, the upper tooling plate 14 is installed. A certain pressing force is applied to the fuel cell stack 4 by the pressing device 23 of the stack assembly equipment to make the fuel cell stack 4 reach the designed fastening height.

[0041] Step 2: Conduct leak tests on the hydrogen passage, air passage, and cooling water passage of fuel cell stack 4.

[0042] Nitrogen gas is used to perform an airtightness leak test on the fuel cell stack 4. All solenoid valves of the outlet device 6 and the inlet device 5 are closed. The pressure regulating valve a33 is adjusted to a leak test pressure of 50-150 kPaG (100 kPaG in this embodiment). The pressure regulating valve a24 of the inlet device 5 is opened to allow nitrogen gas to enter the fuel cell stack 4 and maintain a constant pressure. The value of the flow meter 19 is observed until the value of the flow meter 19 remains stable, and the leakage flow rate of the air channel is recorded. In the same way, by closing other solenoid valves, the corresponding nitrogen gas flows into the cooling water channel, air channel and hydrogen channel respectively. The gas leakage of the corresponding cooling water channel, air channel and hydrogen channel under constant pressure is recorded. If the above-detected leakage value is ≤ the number of membrane electrode stacks of the core 10 of the fuel cell stack 4 × 1.0, the airtightness of the fuel cell stack can be judged to be qualified, and then the subsequent steps can be performed.

[0043] Step 3: Open or close the corresponding valves according to the hydrogen pump activation principle, and activate the fuel cell stack according to the specified test conditions.

[0044] The specified activation test conditions are as follows: the current applied for stack activation is related to the active area of ​​the stack, and its current range is (0.5~1.5A·cm). -2 ) × active area, where the active area is in cm 2The nitrogen supply flow rate is twice the stoichiometric ratio of the activation current of the corresponding fuel cell stack 4, and the hydrogen supply flow rate is twice the stoichiometric ratio of the activation current of the corresponding fuel cell stack 4; the activation time is 5-10 minutes; the activation temperature is room temperature, and the activation pressure is atmospheric pressure. In this embodiment, for the hydrogen pump activation of the fuel cell stack 4, the inlet and outlet solenoid valves connecting the cooling water inlet and outlet channels of the fuel cell stack 4 are closed, the inlet solenoid valve a24 and the outlet solenoid valve e28 are opened to allow nitrogen to enter the air channel of the fuel cell stack 4; the inlet solenoid valve d27 and the outlet solenoid valve g30 are opened to allow hydrogen to enter the hydrogen channel of the fuel cell stack 4; the pressure regulating valves a33 and b34 are adjusted to allow atmospheric pressure intake of the air and hydrogen channels of the fuel cell stack 4, while other solenoid valves are closed; the nitrogen flow rate in the air channel and the hydrogen flow rate in the hydrogen channel are controlled to be 1.0 A / cm², which is the current density of the fuel cell stack 4. 2 Under the condition of 2 times the stoichiometric ratio, and maintaining the hydrogen pump activation time at 5 minutes, the activation is complete. After the fuel cell stack 4 is activated, open the inlet solenoid valves a24, c26, e28, and g30, and purge the air and hydrogen passages of the fuel cell stack 4 with nitrogen for 2 minutes to remove excess hydrogen from the inside of the fuel cell stack 4 and prevent hydrogen leakage in the room.

[0045] Step 4: After the activated fuel cell stack 4 is fastened and assembled, it is taken off the production line, thus successfully completing the stack assembly and activation.

[0046] After the fuel cell stack 4 has been activated, the air intake device 5, the air outlet device 6, and the external power supply 14 are removed (at this time, the fuel cell stack 4 is in a tight state). The fuel cell stack 4 is then tightened, and the tightening force applied by the clamping device 23 is unloaded after the tightening is completed.

[0047] The off-line fuel cell stack 4 was assembled on the fuel cell stack test bench for performance evaluation and verification to determine whether its performance was consistent with that after normal activation. This evaluation and verification method is a standard technical means in the industry and will not be described in detail here.

[0048] In this embodiment, as Figure 7 The image shows 10 tablets with an active area of ​​260 cm². 2The polarization curves of fuel cell stack 4, assembled from single fuel cells, are shown in the test graphs after unactivated, conventional load activation, and hydrogen pump activation. The test conditions for conventional activation were: fuel cell stack 4 temperature 80℃, anode and cathode humidity 100 / 100%, excess coefficient 1.6 / 2.0, hydrogen and air inlet pressures 150 / 140 kPaG respectively, average single-cell voltage maintained at 0.55V, and activation time 5h. The test conditions for hydrogen pump activation were: hydrogen gas introduced into the anode, nitrogen gas introduced into the cathode, hydrogen and nitrogen gas flow rates both 20 L / min, stack maintained at room temperature and pressure, external power supply 14 applied 260A DC current to the stack for 10min. The test conditions for the activated stack were: stack temperature 80℃, anode and cathode humidity 40 / 80%, excess coefficient 1.6 / 2.0, hydrogen and air inlet pressures 150 / 140 kPaG. Figure 7 It can be seen that the performance curve of the hydrogen pump after activation of 10 fuel cell stacks achieved by this invention is basically consistent with the performance obtained by normal activation, at 1.2 A / cm 2 At a current density of 2.0 A / cm², the average voltage after normal activation of the fuel cell stack is 0.668 V, and the average voltage after activation of the fuel cell stack hydrogen pump is 0.667 V, with a difference of only 1 mV; 2 At the specified current density, the average voltage of the fuel cell stack after normal activation is 0.589V, and the average voltage after hydrogen pump activation is 0.588V, with a difference of only 1mV. Comparing the performance of the fuel cell stack after normal activation and after hydrogen pump activation, the integrated fuel cell stack clamping device with activation function designed in this patent can achieve integrated functions of stack assembly, leak detection, and activation while achieving the same performance as the activated stack. Simultaneously, it shortens the activation time by more than 90% and reduces excessive gas consumption caused by normal activation.

[0049] Contents not described in detail in this specification are existing technologies known to those skilled in the art. Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. However, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A leak detection and activation method based on a fuel cell stack clamping device, characterized in that, Includes the following steps: Step 1: Prepare the fuel cell stack and install the entire fuel cell stack between the upper and lower tooling plates of the clamping table. Apply a set force to the fuel cell stack using a clamping device to bring the fuel cell stack to the designed fastening height. Step 2: Perform leak tests on the hydrogen passage, air passage, and cooling water passage of the fuel cell stack. Step 3: Open or close the corresponding valves according to the hydrogen pump activation principle, and activate the fuel cell stack according to the specified test conditions; Step 4: Securely assemble the activated fuel cell stack; The specified activation test conditions are as follows: the current applied for stack activation is (0.5~1.5A•cm). -2 () × active area; nitrogen supply flow rate is twice the metering ratio of the corresponding fuel cell stack activation current, hydrogen supply flow rate is twice the metering ratio of the corresponding fuel cell stack activation current; activation time is 5~10min; An integrated fuel cell stack clamping device with activation function includes a clamping platform, a lower tooling plate, an upper tooling plate, a fuel cell stack, an external power supply, an air inlet device, an air outlet device, and a clamping device. The lower tooling plate is fixed on the clamping platform, and the fuel cell stack is mounted on the lower tooling plate. The positive and negative terminals of the fuel cell stack are connected to the external power supply via wires. The upper tooling plate is located on the top of the fuel cell stack, and a clamping device is installed on the top of the upper tooling plate. An air inlet pipe is opened in the upper tooling plate, and the inlet of the air inlet pipe is connected to the air inlet device. A vertical air inlet channel is opened on one side of the fuel cell stack, and the upper inlet of the air inlet channel is connected to the outlet of the air inlet pipe. A vertical air outlet channel is opened on the other side of the fuel cell stack, and the lower outlet of the air outlet channel is connected to the inlet of the air outlet pipe opened in the lower tooling plate. The outlet of the air outlet pipe is connected to the air outlet device. The fuel cell stack has three sets of air intake channels on one side: a hydrogen intake channel, an air intake channel, and a cooling water intake channel. Each set of air intake channels is equipped with one air intake pipe, meaning there are three air intake pipes on the upper tooling plate, and each air intake pipe is connected to an air intake device. The fuel cell stack also has three sets of air outlet channels on the other side: a hydrogen outlet channel, an air outlet channel, and a cooling water outlet channel. Each set of air outlet channels is equipped with one air outlet pipe, meaning there are three air outlet pipes on the lower tooling plate, and each air outlet pipe is connected to a corresponding air outlet device. The air intake channel and the air outlet channel together form an air channel, the hydrogen intake channel and the hydrogen outlet channel together form a hydrogen channel, and the cooling water intake channel and the cooling water outlet channel together form a cooling water channel.

2. The leak detection and activation method based on the fuel cell stack clamping device as described in claim 1, characterized in that, In step two, the specific leak detection method is as follows: close all solenoid valves of the outlet and inlet devices, adjust the pressure regulating valve to the leak detection pressure, open the pressure regulating valve a of the inlet device to allow nitrogen to enter the fuel cell stack and maintain constant pressure, observe the flow meter value until the flow count value remains stable and record the leakage flow of the air channel; in the same way, close other solenoid valves and open the corresponding nitrogen gas to flow into the cooling water channel, air channel and hydrogen channel respectively, and record the gas leakage of the corresponding cooling water channel, air channel and hydrogen channel under constant pressure.

3. The leak detection and activation method based on the fuel cell stack clamping device as described in claim 1, characterized in that, Leak detection pressure is 50~150 kPaG.

4. The leak detection and activation method based on the fuel cell stack clamping device as described in claim 1, characterized in that, The fuel cell stack includes, from bottom to top, a first end plate, a first insulating plate, a first current collector, a core composed of alternating stacks of multiple bipolar plates and membrane electrode assemblies, a second current collector, a second insulating plate, and a second end plate; the first end plate is mounted on a lower fixture plate; the second end plate is topped by an upper fixture plate, and a sealing ring is provided between the two; the first current collector is a cathode current collector connected to the negative terminal of an external power source via a wire, and the second current collector is an anode current collector connected to the positive terminal of an external power source via a wire; the first end plate, the first insulating plate, and the first current collector... The core has three sets of gas outlet channels that are perpendicularly connected to the gas outlet pipeline, namely hydrogen gas outlet channel, air gas outlet channel and cooling water gas outlet channel; the core, the second current collector, the second insulation plate and the second end plate also have three sets of gas outlet channels that are perpendicularly connected to the gas inlet pipeline, namely hydrogen gas inlet channel, air gas inlet channel and cooling water gas inlet channel. The three sets of gas inlet channels and the three sets of gas outlet channels are located on both sides of the fuel cell stack; the gas entering through each gas inlet channel can flow laterally in the core to the corresponding gas outlet channel and be discharged through the corresponding gas outlet pipeline and gas outlet device.

5. The leak detection and activation method based on the fuel cell stack clamping device as described in claim 4, characterized in that, The air outlet device includes an air outlet pipe, and an outlet temperature and pressure sensor and an outlet solenoid valve installed on the air outlet pipe; one end of the air outlet pipe is connected to the outlet of the air outlet pipeline; the outlet temperature and pressure sensor is used to detect the temperature and pressure of the air outlet pipe.

6. The leak detection and activation method based on the fuel cell stack clamping device as described in claim 5, characterized in that, The air intake device includes a first air intake pipe and a second air intake pipe. One end of the first air intake pipe is connected to the air intake channel and the cooling water intake channel through two branch pipes and corresponding air intake pipes, respectively. Temperature and pressure sensors and inlet solenoid valves are respectively installed on the two branch pipes. The other end of the first air intake pipe is connected to a nitrogen cylinder. A flow meter, a pressure regulating valve a, and a pressure reducing valve are also installed on the first air intake pipe in sequence.

7. The leak detection and activation method based on the fuel cell stack clamping device as described in claim 6, characterized in that, One end of the second intake pipe is connected to the hydrogen intake channel through a corresponding intake pipe, and the other end of the second intake pipe is connected to the hydrogen cylinder. The second intake pipe is sequentially equipped with an inlet temperature and pressure sensor, an inlet solenoid valve d, a pressure regulating valve b, and a pressure reducing valve. The first intake pipe and the second intake pipe are connected by a bypass pipe, and an inlet solenoid valve c is installed on the bypass pipe.

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