Single cell, stack cell and automobile

Abstract

The application provides a single cell, a stack cell and an automobile, relates to the technical field of fuel cells, and comprises two polar plates which are arranged in a stack, and the opposite sides of the two polar plates are each provided with a protruding strip which is used for limiting and / or for guiding flow; along a first direction, a membrane electrode is clamped between the protruding strips of the two polar plates, the membrane electrode comprises a proton exchange membrane, a membrane frame and carbon paper, the membrane frame comprises a hard frame and an inner frame, the inner frame is arranged around the edge of the proton exchange membrane, the hard frame is arranged around the edge of the inner frame and is connected with the proton exchange membrane through the inner frame, the projection range of the hard frame in the first direction is a limiting area, the projection range of the overlapping part of the inner frame and the carbon paper in the first direction is an overlapping area, and the projection range of the proton exchange membrane in the first direction is a reaction area; the protruding height of the protruding strip of the polar plate in the limiting area is H1, the protruding height of the protruding strip in the overlapping area is H2, the protruding height of the protruding strip in the reaction area is H3, and H1 The limiting structure of the carbon paper is simple and easy to produce and manufacture.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, specifically to a single cell, a fuel cell stack, and an automobile. Background Technology

[0002] A fuel cell stack consists of electrodes and a membrane electrode assembly (MEA), forming a power generation unit that converts chemical energy into electrical energy, while simultaneously generating water and releasing heat. Currently, there are two forms of electrode and MEA combination. The first is a separate MEA and bipolar plate structure, where the stack is formed by stacking two main components: bipolar plates and MEA. The second is a single-cell structure, where the MEA has a first and a second electrode mounted on both sides using bonding or other methods, forming a sandwich structure to create a complete power generation unit.

[0003] Because fuel cell individual cells using proton exchange membranes (PEMs) have relatively low voltages (approximately 0.7V), they are often connected in parallel to form a fuel cell stack to meet the demands of high-power automotive fuel cells. The compression force during the assembly of adjacent cells into the fuel cell stack is crucial. Excessive compression force may affect the internal structure of the carbon paper, hindering the transport of reactant gases and thus reducing the performance of both the individual cells and the fuel cell stack. Conversely, insufficient compression force may result in insufficient contact area between the carbon paper and the PEM, leading to excessive contact resistance in the individual cells and negatively impacting the performance of both. Therefore, during the fuel cell stack assembly process, it is essential to ensure appropriate compression of the carbon paper to guarantee optimal performance of both the individual cells and the fuel cell stack.

[0004] Chinese patent (publication number CN116682988A) discloses a single cell and a fuel cell. The single cell includes a bipolar plate, a limiting component, and a membrane electrode assembly (MEA). A gas flow channel is provided on the bipolar plate. The limiting component is disposed on the bipolar plate around the gas flow channel, defining an installation area. A portion of the MEA is connected to the gas flow channel within the installation area, and the remaining portion of the MEA is spaced apart from the limiting component in the thickness direction of the single cell. The length of the MEA in the thickness direction of the single cell is greater than the length of the limiting component in the thickness direction of the single cell. This solution, by setting the limiting component, can effectively avoid overpressure of the carbon paper, ensuring that the proton exchange membrane does not wrinkle or misalign under the compressed state of the fuel cell stack assembly, improving local mechanical strength and the service life of the proton exchange membrane, etc. However, it requires setting the limiting component at specific positions on the electrode plate, making manufacturing relatively complicated.

[0005] A Chinese patent (publication number CN113594486A) discloses an asymmetric fuel cell electrode plate adapted to the size of carbon paper. The plate includes a first electrode plate and a second electrode plate. A cathode carbon paper, an anode carbon paper, and a membrane electrode assembly (MEA) are disposed between the first and second electrode plates. The MEA includes a proton exchange membrane and a rigid frame. The cathode and anode carbon papers are located at one end, and the rigid frame is located at the other end. The proton exchange membrane is located between the cathode and anode carbon papers. The connection between the cathode carbon paper and the rigid frame is a trapezoidal structure. The second electrode plate has stepped slots of corresponding sizes at the flow channel positions of the trapezoidal structure, based on the compression ratio of the cathode and anode carbon papers. This solution effectively avoids over-compression of the carbon paper. While adjusting the compression ratio of the cathode and anode carbon papers by setting the stepped slots is relatively complex to manufacture, this method is quite cumbersome. Summary of the Invention

[0006] One of the objectives of this invention is to provide a single battery, a battery stack, and an automobile to solve the problem that the compression method of carbon paper in the prior art is too cumbersome.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A single battery includes two stacked electrode plates, each of which has a protrusion strip on its opposite side for limiting and / or guiding current, the protrusion strip protruding along a first direction, the thickness direction of the electrode plate being the first direction;

[0009] Along the first direction, a membrane electrode is sandwiched between the protrusions of the two electrode plates. The membrane electrode includes a stacked proton exchange membrane, a membrane frame, and carbon paper. The membrane frame is connected to the edge of the proton exchange membrane and surrounds the proton exchange membrane. The membrane frame includes a rigid frame and an inner frame. The inner frame surrounds the edge of the proton exchange membrane, and the rigid frame surrounds the edge of the inner frame and is connected to the proton exchange membrane through the inner frame. The projection range of the rigid frame in the first direction is a limiting region. The projection range of the overlap between the inner frame and the carbon paper in the first direction is an overlap region. The projection range of the proton exchange membrane in the first direction is a reaction region.

[0010] The height of the protrusion of the electrode plate in the limiting area is H1, the height of the protrusion of the electrode plate in the overlapping area is H2, and the height of the protrusion of the electrode plate in the reaction area is H3, wherein the height of the protrusion of the protrusion of at least one electrode plate is H1 < H2 < H3.

[0011] Optionally, the height of the protrusions on both electrode plates is H1 < H2 < H3.

[0012] Optionally, the portion of the raised strip in the overlapping area that contacts the carbon paper has a dimension along the second direction that is the length of the clearance area, which is 230mm to 240mm.

[0013] Optionally, the single cell includes the reaction region and two distribution regions, the second direction is the length direction of the electrode plate, along the second direction, the reaction region is located between the two distribution regions, the overlapping region is located on the distribution region, and the protrusions in the distribution region are all gap-fitted with the membrane frame.

[0014] Optionally, the single cell includes a reaction zone and two distribution zones. The second direction is the length direction of the electrode plate. Along the second direction, the reaction zone is located between the two distribution zones. In the reaction zone or the distribution zone, a flow channel for gas circulation is formed between adjacent protrusions on the same electrode plate. A vent is provided on the single cell along the first direction, and a flow guiding structure is provided between the vent and the distribution zone. The vent is connected to the flow channel of the distribution zone through the flow guiding structure.

[0015] Optionally, the edge of the vent includes an inlet / outlet edge close to the proton exchange membrane, and the membrane frame has an extension portion extending into the vent in a second direction corresponding to the position of the inlet / outlet edge. The flow guiding structure includes a connecting hole penetrating the extension portion in a first direction and a flow guiding groove formed on the membrane frame. The flow guiding groove extends from the connecting hole to the proton exchange membrane and connects the connecting hole and the flow channel in the corresponding distribution area.

[0016] Optionally, along the extension direction of the inlet and outlet sides, a plurality of connecting holes are arranged at uniform intervals on the protruding portion.

[0017] Optionally, the spacing between two adjacent connecting holes is 0.5mm to 1.5mm, and the width of each connecting hole is 1mm to 2mm; the connecting hole has a connecting edge near the vent, and the connecting edge is arc-shaped.

[0018] Optionally, a diffusion groove is formed on the wall of the connecting hole along the extension direction of the inlet / outlet edge, and the diffusion groove connects each of the connecting holes.

[0019] Optionally, the width of the diffusion groove along the first direction is 0.1mm to 0.2mm.

[0020] The present invention provides a battery stack, comprising single cells as described above, wherein at least two of the single cells are stacked along a first direction to form the battery stack.

[0021] Optionally, the battery stack includes multiple stacked and spaced anode plates and cathode plates. Each anode plate and cathode plate has a first side and a second side. The first side of the anode plate is opposite to the first side of the adjacent cathode plate, and the second side of the anode plate is opposite to the second side of the adjacent cathode plate. Both the anode plate and the cathode plate have raised strips on their first sides, and both the anode plate and the cathode plate have liquid guiding strips on their second sides. The liquid guiding strips on the second side of the anode plate and the liquid guiding strips on the second side of the adjacent cathode plate are arranged intersectingly to form a mesh.

[0022] The present invention also provides an automobile comprising a single battery as described above.

[0023] The beneficial effects of this invention are as follows: By setting protrusions with a height difference in the limiting area and the reaction area of ​​the electrode plate, the compression amount of the carbon paper can be controlled, avoiding excessive or insufficient compression of the carbon paper. This structure is simple and easy to process and manufacture. By setting protrusions in the overlapping area of ​​the electrode plate, the carbon paper surface can be kept flat during the assembly of the single cell, avoiding the carbon paper from curling or wrinkling during the compression process in the reaction area. Attached Figure Description

[0024] Figure 1 This is an exploded schematic diagram of a single cell of the present invention;

[0025] Figure 2 This is a cross-sectional view of the overlapping area of ​​a single cell in this invention along a third direction;

[0026] Figure 3 This is a schematic diagram of the structure between the inlet distribution area and the membrane electrode in this invention;

[0027] Figure 4 This is a schematic diagram of the membrane electrode structure in this invention;

[0028] Figure 5 This is an enlarged schematic diagram of the diffusion groove and connecting hole on the membrane electrode in this invention;

[0029] Figure 6 This is a cross-sectional view of the membrane electrode in this invention, taken along the flow direction of the fuel gas.

[0030] Figure 7 This is an enlarged structural diagram of one end of a single battery in this invention;

[0031] Figure 8 This is a CFD simulation pressure distribution cloud map of the vent of the membrane electrode in this invention.

[0032] Figure 9 This is a schematic diagram of the anode plate in this invention.

[0033] Figure 10 This is a schematic diagram of the anode distribution region in this invention.

[0034] Figure 11 for Figure 10 An enlarged schematic diagram of point A.

[0035] Figure 12 This is a schematic diagram of the cathode plate in this invention.

[0036] Figure 13 This is a schematic diagram of the structure of one electrode in the comparative example.

[0037] Figure 14 This is a schematic diagram of the structure of the other electrode in the comparative example.

[0038] Among them, 1. Anode plate; 101. Anode plate distribution area; 102. Anode plate reaction area; 103. First flow guiding structure; 104. Second flow guiding structure; 105. First branch structure; 106. Second branch structure; 107. First flow guiding channel; 108. Second flow guiding channel; 109. First branch flow channel; 110. Second branch flow channel; 2. Membrane electrode; 201. Connecting hole; 202. Flow guiding groove; 203. Membrane frame; 204. Proton exchange membrane; 205. Extension; 206. Diffusion groove; 207. Hard frame; 208. Inner frame; 209. Membrane electrode fuel gas inlet; 210. Membrane electrode coolant inlet; 211. Membrane electrode oxidation gas inlet; 212. Membrane electrode fuel gas outlet; 213. Membrane electrode coolant outlet; 1. Coolant outlet; 2.14. Oxidizing gas outlet of membrane electrode; 3. Cathode plate; 301. Third flow split structure; 302. Fourth flow split structure; 303. Third branch structure; 4. Gap; 5. Fuel gas inlet; 6. Coolant inlet; 7. Oxidizing gas inlet; 8. Fuel gas outlet; 9. Coolant outlet; 10. Oxidizing gas outlet; 11. Flow channel; 12. Carbon paper; 13. Comparative electrode plate one; 1301. First structure of electrode plate one; 1302. Second structure of electrode plate one; 1303. Third structure of electrode plate one; 1304. Fourth structure of electrode plate one; 14. Comparative electrode plate two; 1401. First structure of electrode plate two; 1402. Second structure of electrode plate two; 1403. Third structure of electrode plate two; 1404. Fourth structure of electrode plate two. Detailed Implementation

[0039] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0040] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0041] This paper will first provide a brief introduction to the technical field involved in this application. Fuel cells are power generation devices that directly convert chemical energy into electrical energy, and they are receiving increasing attention due to their high efficiency, stability, and environmental friendliness. Proton exchange membrane fuel cells are among the most rapidly developing types, possessing advantages such as low operating temperature, high energy conversion efficiency, high energy density, fast start-up, and zero emissions. They are one of the ideal choices for future clean energy, and their applications in new energy, aerospace, military, and defense fields have attracted significant attention and become a research hotspot for many scholars and experts.

[0042] The gas diffusion layer is a crucial component of a proton exchange membrane fuel cell, serving to support the catalyst layer, transport gas, conduct current, and expel water. The gas diffusion layer material needs to possess good permeability, low resistivity, sufficient mechanical strength, and good chemical and thermal stability. Carbon paper 12, manufactured using textile or papermaking techniques and carbonization / graphitization processes, is lightweight, has a smooth surface, is corrosion-resistant, has uniform pore size, high strength, adjustable thickness, and stable performance, making it the preferred material for preparing gas diffusion layers.

[0043] Carbon paper 12 is a composite material with a carbon content as high as 90%, mainly composed of carbon fibers. Carbon fibers have excellent electrical conductivity, so carbon paper 12 also exhibits high electrical conductivity. The carbon fibers in carbon paper 12 are arranged in a disordered manner, resulting in a suitable porosity and good air permeability. Therefore, carbon paper 12 is used as the matrix material for the gas diffusion layer of proton exchange membrane fuel cells. Since carbon paper 12 needs to control the transport of reactant gases from the flow field to the catalyst layer, the irregular arrangement of carbon fibers and its porous structure facilitate the passage of reactant gases, thereby improving battery performance.

[0044] However, carbon paper 12 also suffers from drawbacks such as low overall mechanical strength and high brittleness, making it prone to breakage during use. During the assembly of a single cell, it needs to be sealed using sealing rings or similar methods, inevitably compressing the carbon paper 12 during this process. Appropriate compression of the carbon paper 12 ensures tight contact between it and the protrusions of the proton exchange membrane and the electrode plates, resulting in good cell performance. Excessive compression may damage the internal structure of the carbon paper 12, affecting the transport of reactant gases and reducing cell performance. Insufficient compression makes it difficult to effectively confine the carbon paper 12 within the cell, causing it to slip or wrinkle. It may also result in insufficient contact area between the carbon paper 12 and the protrusions of the protrusions of the protrusions, leading to excessive contact resistance and affecting cell performance. The technical solution in this application addresses these problems, and is further described below:

[0045] Please see Figure 1 and Figure 2 This embodiment proposes a single battery with two electrode plates. Each electrode plate has protruding strips on its opposite sides for limiting and / or guiding current. These protruding strips protrude along a first direction, which is the thickness direction of the electrode plates. A membrane electrode is sandwiched between the protruding strips of the two electrode plates along this first direction. The membrane electrode includes a stacked proton exchange membrane, a membrane frame, and carbon paper. The membrane frame is connected to the edge of the proton exchange membrane and surrounds it. The membrane frame includes a rigid frame and an inner frame. The inner frame surrounds the edge of the proton exchange membrane, and the rigid frame surrounds... The rigid frame is located at the edge of the inner frame and connected to the proton exchange membrane via the inner frame. The projection range of the rigid frame in the first direction is the limiting zone, the projection range of the inner frame overlapping with the carbon paper in the first direction is the overlapping zone, and the projection range of the proton exchange membrane in the first direction is the reaction zone. The height of the protruding strip on the electrode plate within the limiting zone is H1, the height of the protruding strip on the electrode plate within the overlapping zone is H2, and the height of the protruding strip on the electrode plate within the reaction zone is H3. At least one electrode plate has a protruding strip with a height difference of H1 < H2 < H3. By setting protruding strips with height differences in the limiting zone and reaction zone of the electrode plate, the compression amount of the carbon paper can be controlled, avoiding excessive or insufficient compression. This structure is simple and easy to process and manufacture. By setting protruding strips in the overlapping zone of the electrode plate, the carbon paper surface can be kept flat during the assembly of the single cell, preventing the carbon paper from curling or wrinkling during compression in the reaction zone.

[0046] In this embodiment, the height of the protruding strips on both electrodes is H1 < H2 < H3. Both electrodes have the same structure for compressing the carbon paper 12, allowing for more uniform compression of the carbon paper 12 and improving the uniformity of compression. This also avoids the situation where only one side compresses the carbon paper 12, resulting in a larger force on the proton exchange membrane 204 and potentially damaging it. In this embodiment, the difference between the protruding strips in the limiting region and the reaction region of one electrode is C1, and the difference is C2 for the other electrode. It should be noted that when C1 = C2, the compression effect on the carbon paper 12 is optimal. During assembly, a sealing ring ensures the seal between the two electrodes and the membrane electrode 2. During the assembly of a single cell, compression of the carbon paper 12 is unavoidable. When the compression of the carbon paper 12 is too small, the contact area between the carbon paper 12 and the electrode plate is insufficient, resulting in inadequate contact of the reactant gases within the single cell and excessive contact resistance. Conversely, when the compression of the carbon paper 12 is too large, it damages the internal network structure of the carbon paper 12, leading to excessive deformation and affecting its diffusion of reactant gases. Therefore, in actual single-cell assembly, it is necessary to compress the carbon paper 12 while controlling the amount of compression.

[0047] The difference between H2 and H3 is 5μm to 10μm. By limiting the difference between H2 and H3, contact between the raised strip and the carbon paper 12 can be achieved even when there are processing errors in actual assembly. This ensures an interference fit between the raised strip and the carbon paper 12 in the overlapping area, and the carbon paper 12 is still compressed by the raised strip in the overlapping area without affecting the overall compression of the carbon paper 12 in the reaction zone. The above electrode structure is simple, and the raised strip structure of the electrode itself can be used to limit and compress the carbon paper 12 without adding other structures. It also takes into account the incomplete compression of the carbon paper 12 due to tolerances, and has good market promotion value.

[0048] The portion of the raised strip located in the overlapping area that contacts the carbon paper 12 has a clearance length along the second direction, which is 230-240 mm. This raised strip effectively limits the position of the proton exchange membrane 204. (See also...) Figure 5The membrane frame 203 includes a hard frame 207, an inner frame 208, and another hard frame 207 stacked sequentially along a first direction. The hard frame 207 is only disposed at the edge of the inner frame 208. The inner frame 208 is a square frame, and a proton exchange membrane 204 is sandwiched in the middle of the inner frame 208. In this embodiment, one electrode plate is an anode plate 1, and the other electrode plate is a cathode plate 3. When the anode plate 1 is sealed, it cooperates with the hard frame 207. When the protrusion of the anode plate 1 in the overlapping area contacts the carbon paper 12, it has a small clamping compression amount along the first direction. By setting the above clamping compression amount, the carbon paper 12 can be limited during the clamping and limiting process, and the flatness of the carbon paper 12 can be ensured.

[0049] In this embodiment, the contact portions of each protrusion strip in the overlapping area with the proton exchange membrane 204 are arranged along the width direction of the electrode plate. This arrangement can increase the neatness and aesthetics of the protrusion strip arrangement on the electrode plate.

[0050] In this embodiment, four inner frame layers 208 are located near the rigid frame. Within the overlapping area of ​​the membrane frame 203, this is reduced to two inner frame layers 208. The outer two inner frame layers 208 are removed, and the carbon paper 12 is placed on top. Since the carbon paper 12 also provides support, the membrane electrode 2 still maintains good support even after removing the outer two inner frame layers 208. Furthermore, because the four inner frame layers 208 are reduced to two, limiting steps are formed on the outer surfaces of both sides of the inner frame layers 208, further limiting the placement of the carbon paper 12 on the membrane electrode 2.

[0051] Please see Figure 3 The single cell includes a reaction zone and two distribution zones. The second direction is the length direction of the electrode plates. Along this second direction, the reaction zone is positioned between the two distribution zones. The protrusions in the distribution zones are all clearance-fitted with the membrane frame 203 along the first direction. Simultaneously, the distribution zones include overlapping zones, which are close to the reaction zone. The protrusions in the distribution zones are all clearance-fitted with the membrane frame 203 along the first direction, forming gaps 4. Flow channels 11 are formed between adjacent protrusions on the electrode plates. During the flow of the reactive gas in the flow channels 11, it can also diffuse through the gaps 4 between the protrusions and the membrane frame 203 along the first direction, adjusting its own pressure distribution during flow. The gaps 4 improve the uniformity of the reactive gas distribution within the single cell. In this embodiment, the depth of the gaps 4 along the first direction is 20~30μm.

[0052] The single cell includes a reaction zone and two distribution zones. The second direction is along the length of the electrode plate. Along this second direction, the reaction zone is positioned between the two distribution zones. Adjacent protrusions on the same electrode plate form flow channels 11 for gas circulation. A vent is provided on the single cell along a first direction, penetrating the cell. A flow guiding structure is provided between the vent and the outlet or inlet distribution zone. The vent is connected to the flow channels 11 in the distribution zones via the flow guiding structure. The flow guiding structure facilitates the distribution of reactant gas within the distribution zones.

[0053] Please see Figure 6 and Figure 7 As shown, specifically, the edge of the vent includes an inlet / outlet edge near the proton exchange membrane. The membrane frame 203 has a protrusion 205 corresponding to the inlet / outlet edge, overlapping the vent in a first direction. The flow guiding structure includes a connecting hole 201 extending through the protrusion 205 in the first direction and a flow guiding groove 202 formed on the membrane frame 203. The protrusion 205 is located on the side of the vent near the reaction zone. The flow guiding groove 202 extends from the connecting hole 201 towards the proton exchange membrane 204 and connects the connecting hole 201 with the flow channel 11 in the corresponding distribution zone. In the original single cell, the connecting hole 201 is not provided. The reactant gas enters the flow guiding groove 202 through the gas flow opening formed between the flow guiding groove 202 and the corresponding electrode plate. When the connecting hole 201 is not formed on the membrane frame, the reactant gas enters the flow guiding groove 202 of different single cells through the flow guiding opening in the cross-section of the flow guiding groove 202 within the same vent of the stack battery. However, at this point, due to the different reactive gas pressures at the flow openings of different individual cells, the amount of reactive gas entering each individual cell varies, thus affecting the performance of the individual cells and the battery stack. By setting the connecting hole 201, the uniformity of the reactive gas pressure when the reactive gas enters the individual cells in the electric propulsion battery can be improved.

[0054] Please see Figure 8 CFD simulation pressure distribution cloud map of vent opening design, in Figure 8 In the comparison, a battery stack without the connecting hole 201 and a battery stack with the connecting hole 201 in this application are compared. Figure 8 The diagram distinguishes between cells with and without holes. A cell with holes represents the simulated pressure distribution cloud map of a battery stack with a connecting hole 201, while a cell without holes represents the simulated pressure distribution map of a battery stack without the connecting hole 201. It should be noted that in this embodiment, the vent includes an air chamber for air inlet and outlet and a hydrogen chamber for hydrogen inlet and outlet. Simulated pressure tests are conducted using either the air or hydrogen inlet. The battery stack in the comparative example is identical to the battery stack in this application except for the absence of the connecting hole 201. Figure 8 In the diagram, colors represent the pressure values ​​of the reacting gases, from dark blue to red, with the pressure increasing as the reaction gas pressure increases. Figure 8The comparison shows that when a single cell does not have the connecting hole 201, the pressure at the guide channel 202 of the first single cell through which air enters is relatively high, and the concentrated red area is large, indicating that the air pressure at this location is high and the air pressure distribution within the air cavity is extremely uneven. In contrast, with the battery stack having the connecting hole 201, the red concentrated area is significantly reduced, indicating that the gas pressure distribution within the battery stack's air cavity is more balanced after the connecting hole 201 is installed. Similarly, when a single cell does not have the connecting hole 201, the pressure at the guide channel 202 of the first single cell through which hydrogen enters is relatively high, and the concentrated red area is large, indicating that the hydrogen gas pressure at this location is high and the hydrogen gas pressure distribution within the hydrogen cavity is extremely uneven. In contrast, with the battery stack having the connecting hole 201, the red concentrated area becomes a uniform distribution along the hydrogen flow direction, and the pressure at the guide channel 202 is reduced due to being more evenly distributed.

[0055] Please see Figure 4-7 Specifically, the edge of the vent includes an inlet / outlet edge near the proton exchange membrane 204, and a plurality of connecting holes 201 are arranged at uniform intervals along the protrusion 205 of the inlet / outlet edge. The multiple connecting holes 201 increase the flow rate of the reactant gas, and the uniform spacing between the connecting holes 201 further improves the uniformity of the reactant gas distribution in and out of the single cell. Furthermore, the arrangement of the connecting holes 201 is neat and aesthetically pleasing.

[0056] Specifically, the spacing between two adjacent connecting holes is 0.5mm to 1.5mm, and the width of each connecting hole is 1mm to 2mm; the connecting hole has a connecting edge near the vent, and the connecting edge is arc-shaped. By reasonably setting the gap between adjacent connecting holes, the uniformity of the reactant gas when entering and exiting different single cells can be improved. Setting the connecting edge to arc-shaped can reduce the resistance to the entry and exit of reactant gas, and improve the uniformity of gas distribution when the reactant gas enters and exits the single cell.

[0057] Understandably, in a single cell, two different reactive gases flow through both sides of the membrane electrode 2. These two reactive gases undergo a chemical reaction at the proton exchange membrane 204 of the membrane electrode 2 to generate electrical energy. The two reactive gases are fuel gas and oxidizing gas, respectively. The membrane electrode has a positive side for fuel gas and a negative side for oxidizing gas. The membrane electrode 2 is provided with fuel gas inlet 209, fuel gas outlet 212, oxidizing gas outlet 211, oxidizing gas outlet 214, coolant inlet 210, and coolant outlet 213, corresponding to the vents of the single cell. On the positive side, the fuel gas inlet 209 and fuel gas outlet 212 are each provided with a flow guide structure connected to the flow channel of the anode plate in the distribution area, corresponding to their respective inlet and outlet positions. On the negative side, the oxidizing gas outlets 211 and oxidizing gas outlet 214 are each provided with a flow guide structure connected to the flow channel of the cathode plate in the distribution area, corresponding to their respective inlet and outlet positions.

[0058] Please see Figure 7 The anode plate 1 and cathode plate 3 each have an extension portion extending into the vent. Each extension portion overlaps with the projection portion of the connecting hole 201 along the first direction, and each extension portion is located away from the membrane electrode 2 along the first direction. By providing extension portions on the anode plate 1 and cathode plate 3, the opening of the channel for the reaction gas to enter and exit the single cell can be increased, and the path of the reaction gas when entering or leaving the guide groove 202 can be lengthened, thereby reducing the reaction gas pressure when entering and exiting the guide groove and making the gas pressure in the guide groove 202 of each single cell in the stack battery more balanced.

[0059] In detail, the vent includes a fuel gas inlet 5, a fuel gas outlet 8, an oxidation gas inlet 7, and an oxidation gas outlet 10. Each cell has a first end and a second end opposite each other along a first direction. The first end is provided with the fuel gas inlet 5 and the oxidation gas inlet 7, and the second end is provided with the fuel gas outlet 8 and the oxidation gas outlet 10. It should be noted that in this application, the fuel cell has an anode plate 1 and a cathode plate 3, with a membrane electrode 2 sandwiched between the anode plate 1 and the cathode plate 3. The flow channel 11 on the anode plate 1 is used for passing fuel gas, and the flow channel 11 on the cathode plate 3 is used for passing oxidation gas. The reaction gases mentioned in this application are fuel gas and oxidation gas. The fuel gas is hydrogen, and the oxidation gas is air. Hydrogen actually reacts chemically with oxygen in the air to generate electricity. Air and hydrogen are abundant in nature, and hydrogen has a high calorific value, resulting in high energy output after the chemical reaction. Furthermore, the product of the reaction between hydrogen and oxygen is water, which does not pollute the environment. In some embodiments, the fuel gas may also be methane. The type of fuel gas can be adjusted according to actual working needs.

[0060] The third direction is perpendicular to the first direction and the second direction, respectively. The fuel gas inlet 5 and the fuel gas outlet 8 are arranged along the third direction, and the oxidation gas inlet 7 and the oxidation gas outlet 10 are arranged opposite to each other along the third direction. This can increase the uniformity of the distribution of oxidation gas and fuel gas on the electrode plate, thereby improving the overall performance of the single cell.

[0061] In detail, a diffusion groove 206 is formed on the wall of the connecting hole 201 along the extension direction of the inlet and outlet sides, and the diffusion groove 206 connects each connecting hole 201. After the reactant gas enters the connecting hole 201, it diffuses along the hole of the diffusion groove 206, increasing the uniformity of the reactant gas when entering the single cell, so as to improve the overall uniformity of the reactant gas inside the single cell.

[0062] Specifically, the orientation of the connecting hole 201 is perpendicular to the orientation of the diffusion groove 206. This arrangement ensures good diffusion of the reactant gas entering the connecting hole 201, and also results in an aesthetically pleasing and regular structure.

[0063] It should be noted that the first direction mentioned above is the thickness direction of the electrode, the second direction is the length direction of the electrode, and the third direction is the width direction of the electrode.

[0064] The present invention provides a battery stack, comprising a single cell as described above, wherein at least two of the single cells are stacked along a first direction to form the battery stack.

[0065] The battery stack includes multiple stacked and spaced anode plates 1 and cathode plates 3. Both anode plates 1 and cathode plates 3 have a first side and a second side. The first side of the anode plate 1 faces the first side of the adjacent cathode plate, and the second side of the anode plate faces the second side of the adjacent cathode plate. Raised strips are provided on the first side of both the anode and cathode plates, and liquid guiding strips are provided on the second side of both the anode and cathode plates. The liquid guiding strips on the second side of the anode plate and the second side of the adjacent cathode plate intersect and form a mesh. It should be noted that a cooling chamber is formed between the opposing cathode and anode plates of two adjacent cells. This cooling chamber allows coolant to enter and cool the individual cells, preventing excessive heat generation and potential safety hazards. The mesh-like liquid guiding strips within the cooling chamber guide the coolant to diffuse in a third direction, increasing the diffusion area of ​​the coolant and achieving a better cooling effect on the individual cells. It should be noted that a coolant inlet 6 is provided at the first end of the single battery, and a coolant outlet 9 is provided at the second end of the single battery. Coolant enters the single battery through the coolant inlet 6 to cool it, and then flows out through the coolant outlet 9. In this embodiment, the coolant inlet 6 is located at the midpoint of the first end along a third direction, and the coolant outlet 9 is located at the midpoint of the second end along a third direction. The mesh-like protrusions between the two plates guide the coolant flow along a third direction, resulting in good cooling effect on the single battery.

[0066] In this embodiment, the two plates are an anode plate 1 and a cathode plate 3. Both the anode plate 1 and the cathode plate 3 are formed by stamping. Both the anode plate and the cathode plate have a first side and a second side. When the anode plate is stamped, a recess is formed on the first side, and a protrusion is formed on the corresponding second side. If the first side is used for the flow of fuel gas and the other side is used for the flow of coolant, the recess can be a flow channel for the flow of fuel gas, and the protrusion can be a guide strip for the flow of coolant.

[0067] like Figures 9 to 11As shown, in this embodiment, the anode plate 1 is rectangular, and the anode plate has an anode plate vent corresponding to the vent of a single cell. The anode plate has an anode plate distribution area 101 corresponding to the distribution area of ​​a single cell and an anode plate reaction area 102 corresponding to the reaction area of ​​a single cell. The two anode plate distribution areas 101 are located at both ends of the anode plate, and the anode plate reaction area 102 is located in the middle of the two anode plate distribution areas 101. Each anode plate distribution area 101 is provided with an anode plate flow channel distribution structure group. Two anode plate vents are respectively connected to the reaction zone through the corresponding anode plate flow channel distribution structure group of the anode plate distribution area 101. The anode plate flow channel distribution structure group includes a first guide structure 103, a second guide structure 104, a first branch structure 105, and a second branch structure 106 connected in sequence. The vents are respectively connected to the first guide structure 103 of the anode plate flow channel distribution structure group of the anode plate distribution area 101. The second branch structures 106 of the anode plate flow channel distribution structure group of the anode plate distribution area 101 are respectively connected to both ends of the reaction zone. The first guide structure 103 is provided with multiple parallel first guide channels 107, and the second guide structure 104 is provided with multiple parallel second guide channels 105. The two guide channels 108, the first branch structure 105 is provided with multiple first branch channels 109, the second branch structure 106 is provided with multiple second branch channels 110, the second guide structure 104 is split by the first branch structure 105 and then by the second branch structure 106 to connect with the reaction zone, the angle between the first guide channel 107 in the inlet distribution zone and the first direction is the first guide angle, the first guide channel 107 angle is an acute angle, the first guide channel 107 and the second guide channel 108 form a second guide angle, the second guide channel 108 and the first branch channel 109 form a first branch angle, the first branch channel 109 and the second branch channel 110 form a second branch angle, the second guide angle, the first branch angle and the second branch angle are all obtuse angles.

[0068] like Figure 12As shown, in this embodiment, the cathode plate 3 is rectangular and has a cathode plate vent corresponding to the vent of a single cell. The cathode plate has a cathode plate distribution area corresponding to the distribution area of ​​a single cell and a cathode plate reaction area corresponding to the reaction area of ​​a single cell. The two cathode plate distribution areas are located at both ends of the cathode plate, and the cathode plate reaction area is located in the middle of the two cathode plate distribution areas. The cathode plate distribution area has a third diversion structure 301, a fourth diversion structure 302, and a third branch structure 303 connected in sequence. The cathode plate vents are all connected to the third diversion structure 301, and the third branch structures 303 are all connected to the cathode plate reaction area. The third diversion structure 301 is provided with multiple parallel third guide channels, the fourth diversion structure 302 is provided with multiple parallel fourth guide channels, and the third branch structure 303 is provided with multiple parallel third branch channels. The angle between the third guide channel and the first direction is the third guide angle, which is an acute angle. The third guide channel and the fourth guide channel form the fourth guide angle, and the fourth guide channel and the third branch channel form the third branch angle. Both the fourth guide angle and the third branch angle are obtuse angles.

[0069] As can be seen from the above, the second flow guiding structure 104 on the anode plate 1 and the fourth flow splitting structure 302 on the cathode plate 3 are interwoven to form a mesh, and the coolant diffuses in a third direction by means of large-angle flow guidance. At the same time, the flow channels of the distribution areas of the cathode plate and the anode plate are interwoven, so that the cooling chamber in the battery stack has a good cooling effect, forming a mesh structure, increasing the fluid flow channel, forming a fluid outward diffusion trend, and also facilitating the flow and uniform distribution of coolant.

[0070] Please refer to the flow path details of the cathode and anode plates in the distribution area in the comparative example. Figure 11In the comparative example, electrode 13, corresponding to the single-cell distribution area, is sequentially connected to electrode 1 first structure 1301, electrode 1 second structure 1302, electrode 1 third structure 1303, and electrode 1 fourth structure 1304. Each of these structures contains an electrode 1 flow channel. Similarly, in the comparative example, electrode 14, corresponding to the single-cell distribution area, is sequentially connected to electrode 2 first structure 1401, electrode 2 second structure 1402, electrode 2 third structure 1403, and electrode 2 fourth structure 1404. Each of these structures contains an electrode 2 flow channel. When the comparative electrode 13 and the comparative electrode 2 14 are closed to form a cooling chamber, the flow channel of the first electrode of the second structure 1302 and the flow channel of the second electrode of the third structure 1403 guide the coolant to flow along the width direction of the comparative electrode 13. The flow range is small and it is easy to form a flow dead zone. In particular, the second structure 1302 and the third structure 1403 of the second electrode are close to the inlet of the coolant. The trend of the guide strip at the inlet affects the flow uniformity and increases the flow resistance. This structural design is not conducive to the diffusion of the cooling fluid to ensure the flow uniformity and heat dissipation efficiency.

[0071] It should be noted that, except for the different bending directions of the flow channels in the embodiments and comparative examples, all other settings are the same, including the same cross-sectional width and depth of the flow channels in the distribution area in the embodiments and comparative examples, and the same position of the coolant entering the electrode plate.

[0072] This invention provides a comparison with common distribution area water cavity structures compared to this embodiment, for example... Figure 13 and Figure 14 As shown in Table 1, under the same reaction zone flow channel and the same current density, the simulation and measured results of the overall coolant flow resistance of this embodiment and the comparative example are as follows:

[0073]

[0074] It can be seen that the mesh-like arrangement of the protruding strips of the guiding coolant has lower flow resistance compared to the comparative example, both from simulation results and actual measurements. This ensures that the pressure difference across the single cell is within a reasonable range, preventing damage to the membrane electrode due to excessive pressure difference, and also provides good cooling effect for the single cell.

[0075] The present invention provides an automobile comprising a single battery as described above.

[0076] In summary, by setting raised strips with height differences in the limiting area and reaction area of ​​the electrode plates, the compression amount of the carbon paper can be controlled, avoiding excessive or insufficient compression. This structure is simple and easy to process and manufacture. By setting raised strips in the overlapping area of ​​the electrode plates, the carbon paper surface can be kept flat during the assembly of the single cell, preventing the carbon paper from curling or wrinkling during the compression process in the reaction area.

[0077] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A single cell characterized by, The single cell comprises two polar plates arranged in a stack, and a raised strip is arranged on the opposite side of each of the two polar plates for limiting and / or for guiding flow, the raised strip protrudes in a first direction, and the thickness direction of the polar plate is the first direction; In the first direction, a membrane electrode is arranged between the raised strips of the two polar plates, the membrane electrode comprises a proton exchange membrane, a membrane frame and a carbon paper, the membrane frame is connected to the edge of the proton exchange membrane and arranged around the proton exchange membrane, the membrane frame comprises a hard frame and an inner frame, the inner frame is arranged around the edge of the proton exchange membrane, and the hard frame is arranged around the edge of the inner frame and connected to the proton exchange membrane through the inner frame, the projection range of the hard frame in the first direction is a limiting area, the projection range of the inner frame and the carbon paper in the first direction is an overlapping area, and the projection range of the proton exchange membrane in the first direction is a reaction area; The protruding height of the raised strip of the polar plate in the limiting area is H1, the protruding height of the raised strip of the polar plate in the overlapping area is H2, and the protruding height of the raised strip of the polar plate in the reaction area is H3, wherein the protruding height of the raised strip on at least one of the polar plates is H1 The single cell comprises a reaction area and two distribution areas, a second direction is the length direction of the polar plate, along the second direction, the reaction area is located between the two distribution areas, the overlapping area is located on the distribution area, the raised strips in the distribution area are in clearance fit with the membrane frame, the flow channel is formed between the adjacent raised strips on the polar plate, and the reaction gas flows in the flow channel and diffuses through the clearance between the raised strip and the membrane frame in the first direction; in the reaction area or the distribution area, the flow channel for flowing gas is formed between the adjacent raised strips on the same polar plate, the single cell is provided with a gas inlet opening through the single cell in the first direction, the gas inlet opening and the distribution area are provided with a flow guide structure, and the gas inlet opening and the flow channel of the distribution area are in communication through the flow guide structure; The edge of the gas inlet opening comprises an inlet and outlet edge close to the proton exchange membrane, the membrane frame has a protruding part extending into the gas inlet opening in the second direction at the position corresponding to the inlet and outlet edge, the flow guide structure comprises a communication hole penetrating through the protruding part in the first direction and a flow guide groove arranged on the membrane frame, the flow guide groove extends from the communication hole to the proton exchange membrane and communicates the communication hole and the flow channel in the corresponding distribution area.

2. The single cell according to claim 1, characterized by: The protruding height of the raised strip on the two polar plates is H1 3. The single cell according to claim 1 or 2, characterized by: The difference between H2 and H3 is 5 μm to 10 μm.

4. The single cell according to claim 1 or 2, characterized by: The size of the part of the raised strip in the overlapping area in contact with the carbon paper in the second direction is the length of the avoiding area, and the length of the avoiding area is 230 mm to 240 mm.

5. The single cell according to claim 1, characterized by: A plurality of communication holes are arranged on the protruding part in sequence and uniformly in the extension direction of the inlet and outlet edge.

6. The cell according to claim 1 or 5, characterized in that: The distance between two adjacent communicating holes is 0.5-1.5 mm, and the width of each communicating hole is 1-2 mm; the communicating hole has a communicating edge close to the air inlet, and the communicating edge is arc-shaped.

7. The cell according to claim 1 or 5, characterized in that: A diffusion groove is formed on the wall of the communicating hole along the extension direction of the inlet / outlet edge, and the diffusion groove communicates with each communicating hole.

8. The single cell according to claim 7, characterized by: The width of the diffusion groove along the first direction is 0.1-0.2 mm.

9. A stack cell characterized by: The application further discloses a single cell stack comprising at least two single cells as claimed in any one of claims 1-8.

10. The stack cell of claim 9, wherein: The single cell stack comprises a plurality of anode plates and cathode plates which are stacked and arranged at intervals, and each of the anode plates and the cathode plates has a first side and a second side; the first side of the anode plate faces the first side of the adjacent cathode plate, and the second side of the anode plate faces the second side of the adjacent cathode plate; a protruding strip is arranged on the first side of each of the anode plates and the cathode plates; a liquid guide strip is arranged on the second side of each of the anode plates and the cathode plates; the liquid guide strips on the second side of the anode plates and the second side of the adjacent cathode plates are arranged in an intersecting manner to form a mesh shape.

11. An automobile characterized by comprising: The application further discloses a single cell stack comprising at least two single cells as claimed in any one of claims 1-8.

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