Fuel cell stack and fuel cell system having the same

Abstract

The present invention discloses a fuel cell stack and a fuel cell system having the same. The fuel cell stack comprises: a plurality of bipolar plates and membrane electrodes stacked alternately, with glue lines provided on both sides of the bipolar plates for sealing with the membrane electrodes, and areas on both sides of the bipolar plates corresponding to the glue lines comprising a first glue area and a second glue area, wherein the projections of the first glue areas on both sides of the bipolar plates in the thickness direction of the bipolar plates overlap, and the projections of the second glue areas on both sides of the bipolar plates in the thickness direction of the bipolar plates are staggered, and the thickness of the glue lines on the second glue areas is greater than that of the glue lines on the first glue areas, thereby ensuring that the compression rate and sealing performance of the glue lines on the second glue areas are the same as those of the glue lines on the first glue areas, thereby preventing problems such as increased contact resistance, sealing failure, gas leakage, and liquid leakage in the fuel cell stack, thereby improving the performance and reliability of the fuel cell stack.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of batteries, in particular to a fuel cell stack and a fuel cell system having the same. BACKGROUND

[0002] In the related art, during the packaging process of the fuel cell stack, the bipolar plate is easily deformed under the influence of the pressing force, thereby causing the compression rates of the glue lines on different areas of the bipolar plate matched with the membrane electrode to have differences. If the glue lines are excessively compressed, the service life of the glue lines will be affected. If the pressing force is reduced to ensure that the glue lines are at an appropriate compression rate, the contact force between the membrane electrode and the bipolar plate can be lower than the design value, thereby causing problems such as an increase in the contact resistance and a decrease in the performance of the fuel cell stack. SUMMARY

[0003] Therefore, the present application aims to provide a fuel cell stack to improve the performance and reliability of the stack.

[0004] To achieve the above-mentioned purpose, the technical solution of the present application is as follows:

[0005] A fuel cell stack comprises a plurality of bipolar plates and membrane electrodes which are alternately stacked, the two sides of the bipolar plate are provided with glue lines adapted to be sealingly matched with the membrane electrode, the areas corresponding to the glue lines on the two sides of the bipolar plate comprise first glue areas and second glue areas, the projections of the first glue areas on the two sides of the bipolar plate in the thickness direction of the bipolar plate coincide, the projections of the second glue areas on the two sides of the bipolar plate in the thickness direction of the bipolar plate are staggered, and the thickness of the glue line on the second glue area is greater than the thickness of the glue line on the first glue area.

[0006] According to some embodiments of the present application, the thickness a of the glue line on the second glue area and the thickness b of the glue line on the first glue area satisfy the following relationship: 102%b≤a≤105%b.

[0007] According to some embodiments of the present application, the thickness of the glue line is 0.2mm-1.5mm.

[0008] According to some embodiments of the present application, the first glue area and the second glue area are configured as grooves formed on the two sides of the bipolar plate.

[0009] According to some embodiments of the present application, the first glue area is arranged at the circumferential edge of the bipolar plate to be configured as an annular structure, and the second glue area is located in the inner side area of the annular structure.

[0010] According to some embodiments of the present application, one side of the bipolar plate is an anode plate, the other side of the bipolar plate is a cathode plate, the anode plate and the cathode plate are both provided with a layer jump area, and the second glue area is located in the layer jump area.

[0011] According to some embodiments of the present application, the layer jump area is further provided with inlets and outlets of fuel, oxidant and coolant.

[0012] Further, the cathode plate and the anode plate are stamping-formed metal plates.

[0013] Further, the cathode plate and the anode plate are fixed by laser welding.

[0014] Compared with the prior art, the fuel cell stack has the following advantages:

[0015] In the fuel cell stack, the projections of the first glue areas on the thickness direction of the bipolar plate coincide, the projections of the second glue areas on the thickness direction of the bipolar plate are staggered, and the thickness of the glue lines on the second glue areas is greater than that of the glue lines on the first glue areas, so that the compression rate and sealing performance of the glue lines on the second glue areas are the same as those of the glue lines on the first glue areas, to prevent the fuel cell stack from having problems such as increased contact resistance, sealing failure, stack gas leakage and liquid leakage, thereby facilitating the performance and reliability of the fuel cell stack.

[0016] Another object of the present application is to provide a fuel cell system to improve the performance and reliability of the fuel cell system.

[0017] To achieve the above object, the technical scheme of the present application is as follows:

[0018] A fuel cell system comprises the fuel cell stack.

[0019] Compared with the prior art, the fuel cell system has the following advantages:

[0020] In the fuel cell system, the projections of the first glue areas on the thickness direction of the bipolar plate coincide, the projections of the second glue areas on the thickness direction of the bipolar plate are staggered, and the thickness of the glue lines on the second glue areas is greater than that of the glue lines on the first glue areas, so that the compression rate and sealing performance of the glue lines on the second glue areas are the same as those of the glue lines on the first glue areas, to prevent the fuel cell stack from having problems such as increased contact resistance, sealing failure, stack gas leakage and liquid leakage, thereby facilitating the performance and reliability of the fuel cell system. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve the purpose of explaining the present application. The present application should not be limited by the accompanying drawings.

[0022] Figure 1is a schematic view of the bipolar plate of the embodiment of the present application on the side of the anode plate;

[0023] Figure 2 is a schematic view of the bipolar plate of the embodiment of the present application on the side of the cathode plate;

[0024] Figure 3 is Figure 1 sectional view at A-A.

[0025] BRIEF DESCRIPTION OF DRAWINGS

[0026] bipolar plate 100, anode plate 1, cathode plate 2, first glue line 31, second glue line 32, layer jump area 4, anode plate first layer jump area 411, anode plate second layer jump area 412, cathode plate first layer jump area 421, cathode plate second layer jump area 422, first air manifold port layer jump 5, first coolant layer jump 6, first hydrogen layer jump 7, hydrogen gas outlet 8, hydrogen gas inlet 9, second coolant layer jump 10, second air manifold port layer jump 11, second hydrogen layer jump 12, air inlet 13, air outlet 14. DETAILED DESCRIPTION

[0027] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0028] The fuel cell stack of the embodiment of the present application will be described in detail below Figures 1-3 with reference to the accompanying drawings and in conjunction with the embodiments.

[0029] The fuel cell stack according to the embodiment of the present application comprises a plurality of bipolar plates 100 and membrane electrode assemblies (MEAs) arranged in an alternating stack. One membrane electrode assembly and one bipolar plate 100 constitute a basic unit of fuel cell power generation: a single cell. The bipolar plate 100 serves to separate the reaction gas and uniformly guide the reaction gas into the membrane electrode assembly through the flow field, collect and conduct the current, and support the membrane electrode assembly, etc. At the same time, the bipolar plate 100 also undertakes the functions of draining water and dissipating heat of the cell system. The membrane electrode assembly can catalyze the fuel and oxidant guided by the bipolar plate 100 and undergo an electrochemical reaction to generate an electric current and release water and heat to the outside.

[0030] Since the voltage of the single cell is very low (<1V) to achieve the function of fuel cell application, a plurality of single cells need to be connected in series to form an electric stack in order to uniformly distribute the fuel and oxidant to each single cell. Therefore, the sealing between the membrane electrode assembly and the bipolar plate 100 is particularly important. The bipolar plate 100 is provided with glue lines suitable for sealing cooperation with the membrane electrode assembly. The membrane electrode assembly can be correspondingly provided with a sealing frame. Thus, the cooperation of the glue lines on the bipolar plate 100 and the sealing frame on the membrane electrode assembly can ensure the sealing of the fuel cell stack.

[0031] The regions corresponding to the adhesive lines on the two sides of the bipolar plate 100 include a first adhesive region and a second adhesive region, that is, the adhesive lines are fixed on the first adhesive region and the second adhesive region on the two sides of the bipolar plate 100, the projections of the first adhesive region on the two sides of the bipolar plate 100 in the thickness direction of the bipolar plate 100 coincide, and the projections of the second adhesive region on the two sides of the bipolar plate 100 in the thickness direction of the bipolar plate 100 are offset.

[0032] In some embodiments of the present application, the projections of the second adhesive region on the two sides of the bipolar plate 100 in the thickness direction of the bipolar plate 100 are partially offset. In other embodiments of the present application, the projections of the second adhesive region on the two sides of the bipolar plate 100 in the thickness direction of the bipolar plate 100 are completely offset.

[0033] It can be understood that the regions where the adhesive lines are symmetrically arranged on the two sides of the bipolar plate 100 are the first adhesive regions, and the regions where the adhesive lines are asymmetrically arranged on the two sides of the bipolar plate 100 are the second adhesive regions. Since the bipolar plate 100 needs to realize the functions of separating the reaction gas, uniformly introducing the reaction gas into the membrane electrode through the flow field, etc., the second adhesive regions need to be provided on the bipolar plate 100.

[0034] When the fuel cell stack assembly test is performed, a pressurizing force will be applied to the two sides of the bipolar plate 100. Since the adhesive lines on the first adhesive regions on the two sides of the bipolar plate 100 are symmetrically arranged, the stress on the two sides of the bipolar plate 100 at the first adhesive regions is the same, and since the adhesive lines on the second adhesive regions on the two sides of the bipolar plate 100 are asymmetrically arranged, the adhesive lines on the second adhesive regions will cause the bipolar plate 100 to deform under the action of the pressurizing force. To avoid the deformation of the bipolar plate 100 causing the compression rate of the adhesive lines to be lower than the design requirement, resulting in problems such as increased contact resistance, sealing failure, stack gas leakage, liquid leakage, etc., the thickness of the adhesive lines on the second adhesive regions is greater than the thickness of the adhesive lines on the first adhesive regions, so that the increased thickness of the adhesive lines on the second adhesive regions can compensate for the deformation of the bipolar plate 100, thereby ensuring that the compression rate and sealing performance of the adhesive lines on the second adhesive regions are the same as those of the adhesive lines on the first adhesive regions.

[0035] Referring to Figures 1-3 It can be understood that the regions where the adhesive lines are symmetrically arranged on the two sides of the bipolar plate 100 are the first adhesive regions, and the regions where the adhesive lines are asymmetrically arranged on the two sides of the bipolar plate 100 are the second adhesive regions. Since the bipolar plate 100 needs to realize the functions of separating the reaction gas, uniformly introducing the reaction gas into the membrane electrode through the flow field, etc., the second adhesive regions need to be provided on the bipolar plate 100.

[0036] According to the fuel cell stack of the embodiment of the present application, the projections of the first glue areas on the two sides of the bipolar plate 100 in the thickness direction of the bipolar plate 100 coincide, the projections of the second glue areas on the two sides of the bipolar plate 100 in the thickness direction of the bipolar plate 100 are staggered, and the thickness of the glue lines on the second glue areas is greater than the thickness of the glue lines on the first glue areas, so as to ensure that the compression rate and sealing performance of the glue lines on the second glue areas are the same as those of the glue lines on the first glue areas, thereby preventing the fuel cell stack from having problems such as increased contact resistance, sealing failure, gas leakage, liquid leakage and the like, and thus facilitating improvement of the performance and reliability of the fuel cell stack.

[0037] In some embodiments of the present application, the thickness a of the glue lines on the second glue areas and the thickness b of the glue lines on the first glue areas satisfy the following relationship: 102%b≤a≤105%b, that is, the thickness a of the glue lines on the second glue areas is increased by 2% to 5% than the thickness b of the glue lines on the first glue areas, wherein the specific value of the increase of the thickness a of the glue lines on the second glue areas than the thickness b of the glue lines on the first glue areas can be calibrated according to the structure of the bipolar plate 100 and the size of the press-fit force, so as to ensure that the compression amount of the glue lines on the second glue areas is not less than that of the glue lines on the first glue areas, thereby ensuring the effectiveness of the sealing of the glue lines on the second glue areas. For example, when a=103%b, the glue lines on the first glue areas and the glue lines on the second glue areas can both maintain the theoretical compression rate in the assembled fuel cell stack, and the power generation performance of the fuel cell stack is ensured.

[0038] In some embodiments of the present application, the increase value of the thickness a of the glue lines on the second glue areas than the thickness b of the glue lines on the first glue areas is the deformation amount of the bipolar plate 100 caused by the press-fit force on the second glue areas.

[0039] In some embodiments of the present application, the thickness of the glue lines is 0.2mm to 1.5mm, and the thickness of the glue lines can be selected according to the performance of the glue lines and the size of the press-fit force, so as to ensure that the glue lines are maintained within the theoretical compression rate in the assembled fuel cell stack, thereby ensuring the service life of the glue lines and the performance of the fuel cell stack.

[0040] In an embodiment of the present application, the thickness of the glue lines on the first glue areas is 1mm, and the thickness of the glue lines on the second glue areas is 1.03mm.

[0041] In some embodiments of the present application, the first glue areas and the second glue areas are configured as grooves formed on the two sides of the bipolar plate 100, and the grooves are suitable for fixing the glue lines, so as to facilitate the fixation of the glue lines on the two sides of the bipolar plate 100, and a part of the glue lines can be arranged in the grooves, so as to ensure the fixation effect of the glue lines on the bipolar plate 100.

[0042] In some embodiments of the present application, the first glue area is arranged at the circumferential edge of the bipolar plate 100 to form a ring structure, so that the side surface of the bipolar plate 100, the glue line on the first glue area, and the corresponding membrane electrode form a first space, and the second glue area is located at the inner side area of the ring structure to divide the first space into a plurality of sub-first spaces through the glue line on the second glue area to achieve different functions, for example, one of the sub-first spaces can be used for air inlet.

[0043] Referring to Figures 1-3 As shown, one side of the bipolar plate 100 is an anode plate 1, and the other side of the bipolar plate 100 is a cathode plate 2, and the anode plate 1 and the cathode plate 2 are both provided with a layer jump area 4, and the second glue area is located in the layer jump area 4. It can be understood that the layer jump area 4 is used to form a reverse support structure area of the channel between the manifold port B of the bipolar plate 100 and the distribution area C of the bipolar plate 100.

[0044] In some embodiments of the present application, the layer jump area 4 is also provided with inlets and outlets of fuel, oxidant and coolant to achieve the functions of separating reaction gas, uniformly introducing reaction gas into the membrane electrode through the flow field and cooling.

[0045] Referring to Figures 1-3 As shown, the layer jump area 4 on the anode plate 1 includes an anode plate first layer jump area 411 and an anode plate second layer jump area 412, and the distribution area can be located between the anode plate first layer jump area 411 and the anode plate second layer jump area 412. The anode plate first layer jump area 411 is provided with a first air manifold port layer jump 5, a first coolant layer jump 6, a first hydrogen layer jump 7 and a hydrogen outlet 8. The anode plate second layer jump area 412 is provided with a hydrogen inlet 9, a second coolant layer jump 10 and a second air manifold port layer jump 11.

[0046] The layer jump area 4 on the cathode plate 2 includes a cathode plate first layer jump area 421 and a cathode plate second layer jump area 422, and the distribution area can be located between the cathode plate first layer jump area 421 and the cathode plate second layer jump area 422. The cathode plate first layer jump area 421 is provided with a second hydrogen layer jump 12, a second coolant layer jump 10 and an air inlet 13. The cathode plate second layer jump area 422 is provided with an air outlet 14, a first air manifold port layer jump 5, a first coolant layer jump 6 and a first hydrogen layer jump 7.

[0047] In some embodiments of the present application, the cathode plate 2 and the anode plate 1 are stamping formed metal plates, and the stamping forming can ensure the consistency of the shape of each cathode plate 2 and the consistency of the shape of each anode plate 1 in the fuel cell stack, for example, the cathode plate 2 and the anode plate 1 are both precisely stamping formed to ensure the shape accuracy of the cathode plate 2 and the anode plate 1.

[0048] In some embodiments of the present application, the cathode plate 2 and the anode plate 1 are fixed by laser welding to reduce the deformation of the cathode plate 2 and the anode plate 1 during welding, to ensure the welding accuracy of the cathode plate 2 and the anode plate 1, and at the same time, since the thickness of the cathode plate 2 and the anode plate 1 is very thin, generally less than 0.15 mm, laser welding can prevent the phenomenon of re-melting of the cathode plate 2 and the anode plate 1 during welding, to ensure the welding effect.

[0049] According to the fuel cell stack in the embodiments of the present application, the glue lines can be modularly designed in different regions of the bipolar plate 100, and different thicknesses and / or different shapes of the sealing glue lines can be designed in different regions according to the overall structure of the bipolar plate 100 and the pressure deformation state of the bipolar plate 100 during assembly, to avoid problems such as too low sealing compression and sealing failure caused by structural deformation of the bipolar plate 100. In addition, through the modular design of the glue lines, the membrane electrode gas diffusion layer (GDL) can be ensured to be at the theoretical compression rate, and at the same time, the sealing glue lines in the layer jump region are also at the theoretical compression rate, to balance the sealing and power generation performance of the fuel cell stack.

[0050] According to another aspect of the embodiments of the present application, the fuel cell system comprises the fuel cell stack of the above-mentioned embodiments.

[0051] In some embodiments of the present application, the fuel cell stack further comprises end plates and current collecting plates, and the fuel cell stack can be a proton exchange membrane fuel cell (PEMFC). The proton exchange membrane fuel cell is a fuel cell that generates electricity by using hydrogen and air or hydrogen and oxygen as fuel. It does not need to undergo a hydrogen-oxygen combustion reaction, but directly converts the chemical energy of hydrogen and oxygen into electrical energy by using a proton exchange membrane as an electrolyte, without the need for gas compression or heating.

[0052] According to the fuel cell system in the embodiments of the present application, the projections of the first glue areas on the two sides of the bipolar plate 100 in the thickness direction of the bipolar plate 100 coincide, the projections of the second glue areas on the two sides of the bipolar plate 100 in the thickness direction of the bipolar plate 100 are staggered, and the thickness of the glue lines on the second glue areas is greater than the thickness of the glue lines on the first glue areas, so as to ensure that the compression rate and sealing performance of the glue lines on the second glue areas are the same as those of the glue lines on the first glue areas, to prevent problems such as increased contact resistance, sealing failure, stack gas leakage, and liquid leakage of the fuel cell stack, thereby facilitating the improvement of the performance and reliability of the fuel cell system.

[0053] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A fuel cell stack, characterized in that: include: A plurality of bipolar plates (100) and membrane electrodes are alternately stacked, wherein glue lines suitable for sealing with the membrane electrodes are provided on both sides of the bipolar plates (100), and the areas on both sides of the bipolar plates (100) corresponding to the glue lines include a first glue area and a second glue area, the projections of the first glue areas on both sides of the bipolar plates (100) in the thickness direction of the bipolar plates (100) overlap, the projections of the second glue areas on both sides of the bipolar plates (100) in the thickness direction of the bipolar plates (100) are staggered, and the thickness of the glue lines on the second glue areas is greater than the thickness of the glue lines on the first glue areas.

2. The fuel cell stack according to claim 1, characterized in that: The thickness a of the glue line on the second glue area and the thickness b of the glue line on the first glue area satisfy the following relationship: 102%b≤a≤105%b.

3. The fuel cell stack according to claim 1, characterized in that: The thickness of the glue line is 0.2 mm to 1.5 mm.

4. The fuel cell stack according to claim 1, wherein: The first glue area and the second glue area are configured as grooves formed on both sides of the bipolar plate (100).

5. The fuel cell stack according to claim 1, characterized in that: The first glue area is arranged on the circumferential edge of the bipolar plate (100) to form an annular structure, and the second glue area is located in the inner area of ​​the annular structure.

6. The fuel cell stack according to claim 1, characterized in that: One side of the bipolar plate (100) is an anode plate (1), and the other side of the bipolar plate (100) is a cathode plate (2). Both the anode plate (1) and the cathode plate (2) are provided with a layer jump region (4), and the second glue region is located in the layer jump region (4).

7. The fuel cell stack according to claim 6, characterized in that: Inlet and outlet of fuel, oxidant and coolant are also provided in the jump zone (4).

8. The fuel cell stack according to claim 6, characterized in that: The cathode plate (2) and the anode plate (1) are stamped metal plates.

9. The fuel cell stack according to claim 6, characterized in that: The cathode plate (2) and the anode plate (1) are fixed by laser welding.

10. A fuel cell system, characterized in that: Comprising a fuel cell stack according to any one of claims 1 to 9.

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