Fuel cell stack structure and fuel cell system

Abstract

The invention provides a fuel cell stack structure and a fuel cell system, and the fuel cell stack structure comprises a membrane electrode assembly and a first bipolar plate located at the first side of the membrane electrode assembly; a second bipolar plate located on a second side of the membrane electrode assembly; heating channels are arranged on the first bipolar plate and the second bipolar plate; an inlet of the heating channel is communicated with a fuel cell stack cooling water outlet, and an outlet of the heating channel is connected with an external water source. According to the invention, water at the outlet of the fuel cell stack is used for reversely heating the first bipolar plate and the second bipolar plate, and along with heat consumption, the condition that the inlet temperature is high and the outlet temperature is low can be presented, which is just consistent with the temperature of the fuel cell stack; and the membrane electrode assemblies at the two ends of the fuel cell stack can work under the working conditions of high temperature and temperature difference gradient.

Description

Technical Field

[0001] The present invention belongs to the field of fuel cell technology, and in particular relates to a fuel cell stack structure and a fuel cell system. Background Technology

[0002] The fuel cell stack structure can be applied to multiple fuel cells, high-power fuel cells, and working conditions where the ambient temperature changes significantly. The fuel cell stack is composed of multiple groups of graphite plates and membrane electrodes repeatedly stacked and packaged under appropriate stacking force. In order to ensure that the stack can still achieve good sealing and pressure retention after assembly, the packaging is generally composed of metal materials and insulating materials to ensure that the packaging structure of the stack has higher insulation strength and higher rigidity.

[0003] Usually, the graphite plates near the two ends of the fuel cell stack are in contact with the insulating plates. There is coolant in the graphite plates to dissipate the heat generated during the power generation process of the fuel cell stack. Because the insulating plates themselves have thermal conductivity, the plates at both ends are cooled, causing the single cells at the head and tail of the fuel cell stack to operate at a slightly lower temperature. On the one hand, the reaction efficiency of the fuel cell catalyst is reduced under relatively low working conditions, affecting performance. On the other hand, due to the relatively low temperature, the humidity of the group of cells is too high, making it difficult to drain water or even flooding. Long-term operation causes the performance of one or more groups of single cells at the head and tail to decay rapidly, thus affecting the life of the stack.

[0004] At present, the problem of low single-cell fuel cell is solved by control strategy, mainly by adjusting the working conditions, such as increasing the gas metering ratio, reducing the air inlet humidity through bypass, and increasing the water temperature.

[0005] Existing fuel cell stacks usually add one or more groups of dummy cells (single cells that do not participate in the reaction) at the head and tail of the stack to alleviate the problem of low performance caused by low temperature at the head and tail. This method mainly alleviates the uneven intake caused by gas turbulence at the head and tail, and cannot solve the low temperature caused by the temperature of the stack. SUMMARY OF THE INVENTION

[0006] The present invention provides a polarization measurement device and system for optical fiber, which can solve the problem that any measurement error will have a huge impact on the result. At present, the adjustment of polarization angle in experiments is done manually, and the movement of optical components has a certain impact on the power measurement. Manual operation leads to low measurement accuracy and low repeatability, which will lead to test uncertainty and increase the experimental cycle.

[0007] The technical solution provided by the present invention is as follows: On the one hand, a fuel cell stack structure is provided, comprising: Membrane electrode assembly, A first bipolar plate, located on a first side of the membrane electrode assembly; A second bipolar plate, located on a second side of the membrane electrode assembly; The first bipolar plate and the second bipolar plate are both provided with heating channels; The inlet of the heating channel is connected to the cooling water outlet of the fuel cell stack, and the outlet of the heating channel is used to connect to an external water source.

[0008] In an optional embodiment, the heating channel includes a first pipeline arranged along a first direction and a second pipeline arranged along a second direction; The first pipeline is connected to the second pipeline; The first direction and the second direction intersect.

[0009] In an optional embodiment, there are multiple first pipelines, and the multiple first pipelines are arranged side by side along the second direction, and the multiple first pipelines arranged side by side are branches of the second pipeline and are connected to the second pipeline.

[0010] In an optional embodiment, the first pipeline includes a plurality of first sub-pipelines, and the second pipeline includes a plurality of second sub-pipelines; A plurality of first sub-pipelines are arranged along a first direction, and a plurality of second sub-pipelines are arranged along a second direction; Adjacent first sub-pipelines are connected in series through the second sub-pipeline.

[0011] In an optional embodiment, the first bipolar plate includes a metal plate and an insulating plate; The heating channel is arranged on the metal plate or the insulating plate; or The heating channel is arranged on the metal plate and the insulating plate.

[0012] In an optional embodiment, it also includes a conductor, which is arranged between the membrane electrode assembly and the metal plate.

[0013] In an optional embodiment, a water flow channel is provided on the conductor, the inlet of the water flow channel is connected to the cooling water outlet of the fuel cell stack, and the outlet of the water flow channel is used to connect to an external water source.

[0014] In an optional embodiment, an elastic body is further included, and the elastic body is arranged between the metal plate and the insulating plate near the hydrogen outlet end of the fuel cell stack.

[0015] In an optional embodiment, the membrane electrode assembly includes graphite plates and membrane electrodes that are spaced apart.

[0016] In another aspect, a fuel cell system is provided, comprising any of the above-mentioned fuel cell stack structures.

[0017] The optical fiber polarization measurement device provided by the embodiment of the present invention has at least the following beneficial effects: The fuel cell stack structure provided by the embodiment of the present invention is characterized by arranging the first bipolar plate and the second bipolar plate on both sides of the membrane electrode assembly, and arranging heating channels on the first bipolar plate and the second bipolar plate, respectively. The water at the cooling water outlet of the fuel cell stack contains a certain amount of heat. The cooling water heats and insulates the first bipolar plate, the second bipolar plate, and the first single cell sheet in the fuel cell stack adjacent to the first bipolar plate and the second bipolar plate through the first bipolar plate, thereby ensuring that the membrane electrodes at both ends of the stack can operate under reasonable and controllable temperature conditions; and the water at the outlet of the fuel cell stack is used to reversely heat the first bipolar plate and the second bipolar plate. As the heat is consumed, the inlet (first bipolar plate) temperature is high and the outlet (second bipolar plate) temperature is low, which is exactly consistent with the temperature of the fuel cell stack, thereby ensuring that the membrane electrode assemblies at both ends of the fuel cell stack can operate under high temperature and temperature gradient working conditions. Brief Description of the Figures

[0018] The above and other purposes, features and advantages of the present disclosure will become more apparent through a more detailed description of the exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present disclosure.

[0019] Figure 1 This is a schematic diagram of the fuel cell stack structure provided by an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of a heating channel provided on a metal plate in a fuel cell stack structure provided by an embodiment of the present invention.

[0021] Figure 3 A schematic diagram of a heating channel provided on an insulating plate in a fuel cell stack structure provided by an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of providing a heating channel on a conductor in a fuel cell stack structure provided by an embodiment of the present invention.

[0023] Figure 5 and Figure 6 A schematic diagram of the structure of the first pipeline and the second pipeline in the heating channel provided by an embodiment of the present invention.

[0024] Wherein, the accompanying drawings are marked as: 1- membrane electrode assembly, 100- heating channel, 101- first pipeline, 102- second pipeline, 2- first bipolar plate, 21- metal plate, 22- insulation plate, 3- second bipolar plate, 4- conductor, 5- elastomer. Specific implementation method

[0025] The following will describe the embodiments of the present disclosure in more detail with reference to the accompanying drawings. Although the embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0026] The term "including" and its variations used in this document represent open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0027] At present, the problem of low single temperature in fuel cells is solved through control strategies, mainly by adjusting the working conditions, such as increasing the gas metering ratio, reducing the humidity of the air inlet through bypass, increasing the water temperature, etc. Existing fuel cell stacks usually alleviate the problem of low performance caused by low temperature at the head and tail pieces by adding one or more groups of dummy cells (not participating in the reaction) at the head and tail pieces of the stack. This method mainly alleviates the uneven air intake caused by gas turbulence at the head and tail ends, and cannot solve the problem of low single temperature caused by temperature on the stack. Based on this problem, the present invention provides a better solution, which reasonably designs the head and tail side structures of the stack and utilizes the waste heat generated during the operation of the fuel cell to heat it, ensuring that all single cells of the stack work within the project temperature range, thereby solving the problem of low temperature at the head and tail pieces of the fuel cell stack.

[0028] Please see Figure 1 , Figure 1 A schematic diagram of the structure of a fuel cell stack provided in an embodiment of the present invention, comprising: a membrane electrode assembly 1, a first bipolar plate 2 and a second bipolar plate 3; wherein the first bipolar plate 2 is located on the first side of the membrane electrode assembly 1; the second bipolar plate 3 is located on the second side of the membrane electrode assembly 1; a heating channel 100 is provided on both the first bipolar plate 2 and the second bipolar plate 3; the inlet of the heating channel 100 is connected to the cooling water outlet of the fuel cell stack, and the outlet of the heating channel 100 is used to connect to an external water source.

[0029] The optical fiber polarization measurement device provided by the embodiment of the present invention has at least the following beneficial effects: The fuel cell stack structure provided by the embodiment of the present invention is characterized by arranging the first bipolar plate 2 and the second bipolar plate 3 on both sides of the membrane electrode assembly 1, and arranging heating channels 100 on the first bipolar plate 2 and the second bipolar plate 3, respectively. The water at the cooling water outlet of the fuel cell stack contains a certain amount of heat. The cooling water heats and insulates the first bipolar plate 2, the second bipolar plate 3, and the first single cell sheet in the fuel cell stack adjacent to the first bipolar plate 2 and the second bipolar plate 3 through the first bipolar plate 2, so as to ensure that the membrane electrodes at both ends of the stack can work under reasonable and controllable temperature conditions; and the water at the outlet of the fuel cell stack is used to reversely heat the first bipolar plate 2 and the second bipolar plate 3. As the heat is consumed, the temperature of the inlet (first bipolar plate 2) is high and the temperature of the outlet (second bipolar plate 3) is low, which is exactly consistent with the temperature of the fuel cell stack, so as to ensure that the membrane electrode assemblies 1 at both ends of the fuel cell stack can work under high temperature and temperature gradient working conditions.

[0030] The embodiment of the present invention reasonably designs the front and rear side structures of the stack and utilizes the waste heat generated during the operation of the fuel cell system to heat it, ensuring that all cells in the fuel cell stack operate within the project temperature range, ensuring that the front and rear end cells of the fuel cell operate within the ideal temperature range, and avoiding low reaction efficiency due to too low operating temperature and drainage difficulties or even flooding due to excessive humidity.

[0031] Please see Figure 2 , Figure 2 The arrow direction in indicates the water flow direction in the heating channel 100 in the embodiment of the present invention. Please also refer to Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of a heating channel provided on a metal plate in a fuel cell stack structure provided by an embodiment of the present invention. Figure 3 A schematic diagram of a heating channel provided on an insulating plate in a fuel cell stack structure provided by an embodiment of the present invention.

[0032] In an optional embodiment, the membrane electrode assembly 1 includes graphite plates and membrane electrodes that are spaced apart.

[0033] In the embodiment of the present invention, a plurality of spaced graphite plates and membrane electrodes form a membrane electrode assembly 1, providing a chemical reaction center for the fuel cell structure.

[0034] Please see Figure 5 and Figure 6 , in an optional embodiment, the heating channel 100 includes a first pipeline 101 arranged along a first direction and a second pipeline 102 arranged along a second direction; the first pipeline 101 and the second pipeline 102 are connected; the first direction intersects the second direction.​

[0035] As an example, the angle between the first direction and the second direction may be 30°-90°. Preferably, the angle between the first direction and the second direction may be 90°.

[0036] The first pipeline 101 can be connected to the cooling water outlet of the fuel cell stack, and the second pipeline 102 can be used to connect to an external water source.

[0037] Please see Figure 5 , it should be noted that there are two ways to set the heating channel 100 provided in the embodiment of the present invention, namely the first way: there are multiple first pipelines 101, the multiple first pipelines 101 are arranged side by side along the second direction, and the multiple first pipelines 101 arranged side by side are branches of the second pipeline 102 and are connected to the second pipeline 102.

[0038] In the embodiment of the present invention, the first direction may be a direction perpendicular to the horizontal plane, and the second direction may be a direction parallel to the horizontal plane.

[0039] Please see Figure 6 , the second way is: the first pipeline 101 includes multiple first sub-pipelines, the second pipeline 102 includes multiple second sub-pipelines; the multiple first sub-pipelines are arranged along the first direction, and the multiple second sub-pipelines are arranged along the second direction; adjacent first sub-pipelines are connected in series through the second sub-pipelines.

[0040] In other words, the first sub-pipeline and the second sub-pipeline in the first pipeline 101 are connected in series to form a "Z"-shaped connection.

[0041] The third method is: the first method and the second method are arranged alternately, that is, the heating channel 100 can be partially arranged with multiple first pipelines 101 arranged side by side along the second direction as needed, and the multiple first pipelines 101 arranged side by side are branches of the second pipeline 102 and are connected to the second pipeline 102. It is also possible to partially set the first sub-pipeline and the second sub-pipeline in the first pipeline 101 in series as needed to form a "Z"-shaped connection.

[0042] Through the above arrangement, the heating efficiency of the heating channel 100 on the first bipolar plate 2, the second bipolar plate 3 and the first and last monolithic cells of the fuel cell stack can be improved. And the heating speed and heating efficiency can be better controlled, making the heating easy to control.

[0043] In an optional embodiment, the first bipolar plate 2 includes a metal plate 21 and an insulating plate 22; the heating channel 100 is disposed on the metal plate 21 or the insulating plate 22; or the heating channel 100 is disposed on the metal plate 21 and the insulating plate 22.

[0044] The heating channel 100 provided in the embodiment of the present invention can be arranged on the metal plate 21 or the insulating plate 22; or it can be arranged on the metal plate 21 and the insulating plate 22.

[0045] The above arrangement can improve the selection of heating for the first and last cells of the fuel cell stack, that is, the heating channel 100 can be set on the metal plate 21 and the insulating plate 22 as needed to improve the heating efficiency, or the heating channel 100 can be set only on the metal plate 21 or only on the insulating plate 22 as needed.

[0046] Please see Figure 4 , in an optional embodiment, it also includes a conductor 4, which is arranged between the membrane electrode assembly 1 and the metal plate 21.

[0047] In the embodiment of the present invention, a conductor 4 can be arranged between the membrane electrode assembly 1 and the metal plate 21, and the conductor is directly in contact with the first bipolar plate 2 or the second bipolar plate 3, so that heat transfer is more direct.

[0048] In an optional embodiment, a water flow channel is provided on the conductor 4, the inlet of the water flow channel is connected to the cooling water outlet of the fuel cell stack, and the outlet of the water flow channel is used to connect to an external water source.

[0049] It is understandable that when setting the conductor 4, it is necessary to perform anti-corrosion treatment on the conductor 4, and it is necessary to design a water flow channel in the conductor, and use the water at the outlet of the stack to reversely heat the component to ensure that the membrane electrodes at both ends of the stack can work under high temperature and temperature gradient working conditions. In view of this, the embodiment of the present invention sets a water flow channel on the conductor 4, which can enable the conductor 4 to transfer heat on the one hand, and on the other hand, can ensure that the conductor 4 is not corroded.

[0050] Please see Figure 3 , in an optional embodiment, it also includes an elastic body 5, which is arranged between the metal plate 21 and the insulating plate 22 near the hydrogen outlet end of the fuel cell stack.

[0051] On the other hand, a fuel cell system is provided, comprising any of the above fuel cell stack structures.

[0052] When the fuel cell system provided by the embodiment of the present invention is turned on, the cooling water outlet of the fuel cell stack is controlled to be connected with the inlet of the heating channel 100, so as to quickly heat the first bipolar plate 2 and the second bipolar plate 3 so that the first bipolar plate 2 and the second bipolar plate 3 can reach the rated operating temperature as soon as possible.

[0053] During the operation of the fuel cell system, the temperature of the first and last monolithic cells of the fuel cell is obtained in real time. When the temperature of the first and last monolithic cells of the fuel cell is lower than the preset temperature, the heating channels 100 on the first bipolar plate 2 and the second bipolar plate 3 provided in the embodiment of the present invention can be used to heat and keep them warm, so as to avoid abnormal operation due to too low ambient temperature. During the shutdown process, the plate can continue to be maintained at a higher temperature to avoid the temperature dropping too fast, which will cause liquid water in the internal performance and affect the product performance.

[0054] Furthermore, the embodiment of the present invention can obtain the temperature of the first and last monolithic cells of the fuel cell, and determine whether to pass water through the heating channel 100 on the metal plate 21 or the insulating plate 22 or pass water through the heating channel 100 on the metal plate 21 and the insulating plate 22 to heat at the same time according to the temperature of the first and last monolithic cells of the fuel cell, so as to improve the heating efficiency.

[0055] The above has described various embodiments of the present disclosure, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used in this article is intended to best explain the principles of the embodiments, practical applications or technical improvements in the market, or to enable other ordinary technicians in the art to understand the embodiments disclosed herein.

Claims

1. A fuel cell stack structure, characterized in that: include: Membrane electrode assembly, a first bipolar plate located on a first side of the membrane electrode assembly; a second bipolar plate located on a second side of the membrane electrode assembly; The first bipolar plate and the second bipolar plate are both provided with heating channels; The inlet of the heating channel is in communication with the cooling water outlet of the fuel cell stack, and the outlet of the heating channel is used to connect to an external water source.

2. The fuel cell stack structure according to claim 1, characterized in that: The heating channel includes a first pipeline arranged along a first direction and a second pipeline arranged along a second direction; The first pipeline is connected to the second pipeline; The first direction and the second direction intersect.

3. The fuel cell stack structure according to claim 2, characterized in that: There are multiple first pipelines, and the multiple first pipelines are arranged side by side along the second direction. The multiple first pipelines arranged side by side are branches of the second pipeline and are connected to the second pipeline.

4. The fuel cell stack structure according to claim 2, characterized in that: The first pipeline includes a plurality of first sub-pipelines, and the second pipeline includes a plurality of second sub-pipelines; A plurality of first sub-pipelines are arranged along a first direction, and a plurality of second sub-pipelines are arranged along a second direction; Adjacent first sub-pipelines are connected in series via the second sub-pipelines.

5. The fuel cell stack structure according to claim 1, characterized in that: The first bipolar plate includes a metal plate and an insulating plate; The heating channel is arranged on the metal plate or the insulating plate; or The heating channel is disposed on the metal plate and the insulating plate.

6. The fuel cell stack structure according to claim 5, characterized in that: Also included is an electrical conductor, which is disposed between the membrane electrode assembly and the metal plate.

7. The fuel cell stack structure according to claim 6, characterized in that: The conductor is provided with a water flow channel, the inlet of the water flow channel is connected with the cooling water outlet of the fuel cell stack, and the outlet of the water flow channel is used to connect to an external water source.

8. The fuel cell stack structure according to claim 5, characterized in that: The invention also includes an elastic body, which is arranged between the metal plate and the insulating plate near the hydrogen outlet end of the fuel cell stack.

9. The fuel cell stack structure according to claim 1, characterized in that: The membrane electrode assembly comprises graphite plates and membrane electrodes which are arranged at intervals.

10. A fuel cell system, characterized in that: A fuel cell stack structure comprising the structure described in any one of claims 1 to 9.

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