Fuel cell bipolar plate flow field structure and fuel cell stack

Abstract

The invention discloses a fuel cell bipolar plate flow field structure and a fuel cell stack, the fuel cell bipolar plate flow field structure comprises a cathode monopole plate and an anode monopole plate which are stacked, an air flow field is arranged on the outer side of the cathode monopole plate, and a plurality of cathode plate convex ridges and cathode plate flow channel grooves which are sequentially arranged in a staggered manner are arranged on the side of the air flow field; the depths of every two adjacent cathode plate runner grooves are different, and the depths of the multiple cathode plate runner grooves are distributed in a deep-shallow staggered mode; a fuel gas flow field is arranged on the outer side of the anode monopole plate, the anode monopole plate comprises a plurality of anode plate convex ridges and anode plate runner grooves which are sequentially arranged in a staggered manner on the fuel gas flow field side, the widths of two adjacent anode plate convex ridges are different, and the widths of the plurality of anode plate convex ridges are distributed in a wide-narrow staggered manner; the positions of the plurality of cathode plate runner grooves and the positions of the plurality of anode plate convex ridges are in one-to-one correspondence; the bipolar plate is high in strength, and when the bipolar plate is applied to a fuel cell stack, the volume power density of the stack can be improved, and the reaction rate of a fuel cell is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a bipolar plate flow field structure of a fuel cell and a fuel cell stack. Background Art

[0002] With the continuous development of the new energy industry, fuel cells are being used in more and more scenarios. Fuel cells are energy conversion devices that can directly convert chemical energy of reactive fuels such as hydrogen into electrical energy through electrochemical reactions. They have broad development and application prospects in the future due to their high power density, fast start-up speed, high conversion efficiency, low environmental pollution, easy access to raw materials, clean and efficient.

[0003] The fuel cell includes a membrane electrode and a bipolar plate. The bipolar plate is fixed on both sides of the membrane electrode and serves to separate the oxidant, reductant and coolant. The membrane electrode includes a gas diffusion layer and a catalyst layer. The oxidant or reductant passes through the gas diffusion layer and reacts in the catalyst layer, and water is generated in the reaction. The gas side and water side of the stamped plate affect each other in structure. The ridge structure on the gas side of the plate is a flow channel structure in the water channel. These structures form a channel for the circulation of cooling water on the bipolar plate.

[0004] Most of the existing stamped anode and cathode plates adopt a structure in which the depth of all flow channels is consistent, which makes it difficult for the reaction gas to flow between adjacent flow channels, and is not conducive to removing the liquid water in the diffusion layer under the ridge. The accumulation of liquid water will reduce the performance of the fuel cell. In addition, the plate combination strength is not high, and it is easy to fall apart and leak when impacted or bumped, further reducing the electrochemical performance of the battery. Summary of the invention

[0005] The purpose of the present invention is to provide a fuel cell bipolar plate flow field structure and a fuel cell stack to solve the following technical problems:

[0006] How to improve the strength and electrochemical performance of the flow field structure of fuel cell bipolar plates.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] In a first aspect, the present invention discloses a bipolar plate flow field structure for a fuel cell, comprising a cathode monopolar plate and an anode monopolar plate arranged in a stacked manner, with a cooling water flow field formed between the two;

[0009] The cathode monopolar plate has an air flow field outside, and the cathode monopolar plate includes a plurality of cathode plate ridges and cathode plate flow channels arranged in sequence and staggered on the air flow field side, the depths of two adjacent cathode plate flow channels are different, and any cathode plate flow channel is the same as the depth of two separated cathode plate flow channels, so that the depths of the plurality of cathode plate flow channels are staggered in deep and shallow distribution;

[0010] The outer side of the anode monopolar plate is a fuel gas flow field, and the anode monopolar plate includes a plurality of anode plate ridges and anode plate flow channel grooves arranged in sequence on the fuel gas flow field side, the widths of two adjacent anode plate ridges are different, and any anode plate ridge is the same as the width of two separated anode plate ridges, so that the widths of the plurality of anode plate ridges are staggered in wide and narrow distribution;

[0011] The positions of the plurality of cathode plate flow channel grooves and the plurality of anode plate ridges correspond one to one.

[0012] In a further embodiment of the present invention, the deeper cathode plate flow channel grooves correspond to the positions of the narrower anode plate ridges, and the shallower cathode plate flow channel grooves correspond to the positions of the wider anode plate ridges.

[0013] In a further embodiment of the present invention, the deeper cathode plate flow channel groove forms a ridge on the cooling water flow field side, and the narrower anode plate ridge forms a groove on the cooling water flow field side, and the ridge is embedded and fits in the corresponding groove to form a nested structure.

[0014] In a further embodiment of the present invention, a wider anode plate ridge and anode plate flow channel grooves on both sides thereof

[0015] and

[0016] A coolant cavity is formed between a shallow cathode plate flow channel groove and cathode plate ridges on both sides thereof on the cooling water flow field side.

[0017] In a further embodiment of the present invention, the depth of the deeper cathode plate flow channel grooves ranges from 0.3 to 0.5 mm, and the depth of the shallower cathode plate flow channel grooves ranges from 0.2 to 0.3 mm.

[0018] In a further embodiment of the present invention: the widths of two adjacent cathode plate flow channel grooves are the same; the widths and heights of two adjacent cathode plate ridges are the same.

[0019] In a further embodiment of the present invention, the width of the narrower anode plate ridge is in the range of 0.5-1.0 mm, and the width of the wider anode plate ridge is in the range of 0.6-1.2 mm; the depth of the anode plate flow channel groove is in the range of 0.2-0.35 mm.

[0020] In a further embodiment of the present invention, the heights of the ridges of two adjacent anode plates are the same; the widths and depths of the flow channel grooves of two adjacent anode plates are the same.

[0021] In a further embodiment of the present invention, the cathode monopolar plate and the anode monopolar plate are processed by stamping, molding and etching.

[0022] In a second aspect, the present invention further discloses a fuel cell stack, comprising bipolar plates and membrane electrodes stacked in series, wherein the bipolar plates are the fuel cell bipolar plate flow field structure as described above.

[0023] Beneficial effects of the present invention:

[0024] (1) In the flow field structure of the fuel cell bipolar plate of the present invention, the depths of the two adjacent cathode plate flow channel grooves on the cathode plate are different, and the widths of the anode plate ridges are different. The deeper cathode plate flow channel groove forms a ridge in the cooling water flow field, and the narrower anode plate ridge forms a groove in the cooling water flow field. The nested structure formed by the ridges embedded in the corresponding grooves plays a positioning role in the bipolar plate. Through the positioning of these nested structures, the cathode plate and the anode plate form a stable cooling water cavity, which can be used as a channel for the circulation of the coolant. On the other hand, the ridge formed by the cathode plate flow channel groove is tightly connected with the groove formed by the cathode plate flow channel groove to form an electron path for the bipolar plate. In addition, the nested structure also strengthens the structural strength of the bipolar plate, supports the cooling liquid cavity and supports the membrane electrode at the same time.

[0025] (2) In the fuel cell stack of the present invention, since the depths of adjacent cathode plate flow channel grooves vary alternately between deep and shallow, and the widths of adjacent anode plate ridges vary alternately between narrow and wide, the deeper cathode plate flow channel grooves can form ridges in the cooling water flow field, and the narrower cathode plate flow channel grooves can form grooves in the cooling water flow field. The ridges are embedded in the corresponding grooves to realize a bipolar plate combination structure. This embedded structure can make the overall thickness of the bipolar plate smaller, which is beneficial to reducing the length of the stack core and thereby improving the volume power density of the stack.

[0026] (3) In the fuel cell stack of the present invention, since the depths of adjacent cathode plate flow channel grooves show alternating changes between deep and shallow, the flow velocities of the gas in adjacent cathode plate flow channel grooves can be different, which can promote the flow of gas between the grooves of the cathode plate flow channel grooves with fast flow rates through the sub-ridge diffusion layer, blow the water accumulated in the sub-ridge diffusion layer to the adjacent cathode plate flow channel grooves with slow flow rates, and discharge it along with the flow channel gas, thereby preventing the reaction from being affected by the accumulated water and improving the reaction rate of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below in conjunction with the accompanying drawings.

[0028] Figure 1 is a schematic structural diagram of the flow field structure of the bipolar plate of a fuel cell in Example 1 of the present invention;

[0029] Figure 2 is a schematic structural diagram of the cathode monopolar plate 1 in Example 1 of the present invention;

[0030] Figure 3 is a schematic structural diagram of the anode monopolar plate 2 in Example 1 of the present invention;

[0031] Figure 4 It is a cross-sectional view of the flow field structure of the bipolar plate of the fuel cell in Example 1 of the present invention.

[0032] Figure numerals: 1, cathode monopolar plate; 101, cathode plate ridge; 102, cathode plate flow channel groove; 2, cathode monopolar plate; 201, anode plate ridge; 202, anode plate flow channel groove. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] See also Figure 1 The present invention discloses a fuel cell bipolar plate flow field structure, comprising a cathode monopolar plate 1 and an anode monopolar plate 2 arranged in a stacked manner, an air flow field is arranged on the outer side of the cathode monopolar plate 1, a fuel gas flow field is arranged on the outer side of the anode monopolar plate 2, and a cooling water flow field is formed between the cathode monopolar plate 1 and the anode monopolar plate 2.

[0036] See also Figure 2 The cathode monopolar plate 1 on the air flow field side includes a plurality of cathode plate ridges 101 and cathode plate flow channels 102 arranged alternately in sequence, the heights and widths of the cathode plate ridges 101 are all kept the same, the widths of two adjacent cathode plate flow channels 102 are the same, but the depths are different, and the depths of the plurality of cathode plate flow channels 102 are alternately distributed in deep and shallow depths, wherein the depth of the deeper cathode plate flow channel 102 is 0.4 mm, and the depth of the shallower cathode plate flow channel 102 is 0.25 mm.

[0037] It should be noted that the depth of the cathode plate flow channel groove 102 is not limited to the depth in this embodiment. In other embodiments, the depth of the cathode plate flow channel groove 102 can also be adjusted according to the situation, as long as the depth range of the deeper cathode plate flow channel groove 102 is 0.3-0.5mm, and the depth range of the shallower cathode plate flow channel groove 102 is 0.2-0.3mm, but it is necessary to satisfy that the depth of the deeper cathode plate flow channel groove 102 is greater than the depth of the shallower cathode plate flow channel groove 102.

[0038] See also Figure 3The fuel gas flow field of the anode monopolar plate 2 on the fuel gas flow field side includes a plurality of staggered anode plate ridges 201 and anode plate flow channel grooves 202. The depths of two adjacent anode plate ridges 201 are the same, but the widths are different. The widths of the plurality of anode plate ridges 201 are staggered in narrow and wide widths. Among them, the width of the narrower anode plate ridge 201 is 0.8 mm, and the width of the wider anode plate ridge 201 is 1.0 mm. The depths of the anode plate flow channel grooves 202 remain the same, which is 0.30 mm.

[0039] It should be noted that the width of the anode plate ridge 201 is not limited to the width in the present embodiment. In other embodiments, the width of the anode plate ridge 201 can also be adjusted according to the situation, as long as the width range of the narrower anode plate ridge 201 is 0.5-1.0mm and the width range of the wider anode plate ridge 201 is 0.6-1.2mm; similarly, in other embodiments, the depth range of the anode plate flow channel groove 202 can be maintained at 0.2-0.35mm.

[0040] See also Figure 4 , the positions of the plurality of cathode plate flow channel grooves 102 and the plurality of anode plate ridges 201 correspond one to one, specifically, the deeper cathode plate flow channel grooves 102 correspond to the narrower anode plate ridges 201, and the shallower cathode plate flow channel grooves 102 correspond to the wider anode plate ridges 201; at the same time, the deeper cathode plate flow channel grooves 102 form ridges in the cooling water flow field, and the narrower anode plate ridges 201 form grooves in the cooling water flow field, and the ridges are embedded and fit in the corresponding grooves to form a nested structure, thereby realizing the stacking of the cathode monopolar plate 1 and the anode monopolar plate 2; at the same time, a coolant cavity is formed on the cooling water flow field side between a wider anode plate ridge 201 and the anode plate flow channel grooves 202 on both sides thereof and a shallower cathode plate flow channel groove 102 and the cathode plate ridges 101 on both sides thereof. , for the coolant to pass through.

[0041] Specifically, the nested structure formed by the ridges embedded in the corresponding grooves plays a positioning role in the bipolar plate on the one hand, and through the positioning of these nested structures, the cathode monopolar plate 1 and the anode monopolar plate 2 form a stable cooling water flow field, and these cooling water flow fields can be used as channels for the circulation of coolant; on the other hand, these nested structures also form a circuit path and can play a role of structural support. The ridges formed by the cathode plate flow channel grooves 102 are tightly connected with the grooves formed by the cathode plate flow channel grooves 102 to form an electronic path for the bipolar plate; in addition, the nested structure also strengthens the structural strength of the bipolar plate, supports the cooling liquid cavity and supports the membrane electrode at the same time.

[0042] Example 2

[0043] This embodiment discloses a fuel cell stack, including bipolar plates and membrane electrodes stacked in series, wherein the bipolar plates are the fuel cell bipolar plate flow field structure described in Embodiment 1. The cathode monopolar plate 1 and the anode monopolar plate 2 are processed by stamping, molding, and etching. The working principle of the present invention is:

[0044] On the one hand, since the depths of adjacent cathode plate flow channel grooves 102 show alternating changes between deep and shallow, and the widths of adjacent anode plate ridges 201 show alternating changes between narrow and wide, the deeper cathode plate flow channel grooves 102 can form ridges in the cooling water flow field, and the narrower cathode plate flow channel grooves 102 can form grooves in the cooling water flow field. The ridges are embedded in the corresponding grooves to realize a bipolar plate combination structure. This mosaic structure can make the overall thickness of the bipolar plate smaller, which is beneficial to reducing the length of the fuel cell core and thereby improving the volume power density of the fuel cell.

[0045] On the other hand, since the depths of adjacent cathode plate flow grooves 102 show alternating changes between deep and shallow, the flow velocities of the gas in adjacent cathode plate flow grooves 102 can be different, which can promote the flow of gas between the grooves of the cathode plate flow grooves 102 with fast flow velocities to flow through the sub-ridge diffusion layer, and blow the water accumulated in the sub-ridge diffusion layer to the adjacent cathode plate flow grooves 102 with slow flow velocities, and discharge it along with the flow groove gas, thereby preventing the reaction from being affected by water accumulation and improving the reaction rate of the fuel cell.

[0046] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction and a specific direction structure and operation, and therefore, cannot be understood as a limitation on the present invention. In addition, "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0047] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A fuel cell bipolar plate flow field structure, characterized in that: It comprises a cathode monopolar plate (1) and an anode monopolar plate (2) which are stacked and a cooling water flow field is formed between the two; The cathode monopolar plate (1) has an air flow field outside, and the cathode monopolar plate (1) comprises a plurality of cathode plate ridges (101) and cathode plate flow channel grooves (102) arranged in sequence and staggered on the air flow field side, the depths of two adjacent cathode plate flow channel grooves (102) are different, and any cathode plate flow channel groove (102) has the same depth as two separated cathode plate flow channel grooves (102), so that the depths of the plurality of cathode plate flow channel grooves (102) are distributed in a deep and shallow staggered manner; The outer side of the anode monopolar plate (2) is a fuel gas flow field, and the anode monopolar plate (2) comprises a plurality of anode plate ridges (201) and anode plate flow channel grooves (202) arranged in sequence and staggered on the fuel gas flow field side, the widths of two adjacent anode plate ridges (201) are different, and any anode plate ridge (201) is the same as the width of two separated anode plate ridges (201), so that the widths of the plurality of anode plate ridges (201) are distributed in a wide and narrow staggered manner; The positions of the plurality of cathode plate flow channel grooves (102) and the plurality of anode plate ridges (201) correspond one to one.

2. The fuel cell bipolar plate flow field structure according to claim 1, characterized in that: The deeper cathode plate flow channel groove (102) corresponds to the position of the narrower anode plate ridge (201), and the shallower cathode plate flow channel groove (102) corresponds to the position of the wider anode plate ridge (201).

3. The fuel cell bipolar plate flow field structure according to claim 2, characterized in that: The deeper cathode plate flow channel groove (102) forms a ridge on the cooling water flow field side, and the narrower anode plate ridge (201) forms a groove on the cooling water flow field side, and the ridge is embedded and fits in the corresponding groove to form a nested structure.

4. The fuel cell bipolar plate flow field structure according to claim 2, characterized in that: A wider anode plate ridge (201) and anode plate flow channel grooves (202) on both sides thereof and A coolant cavity is formed between a shallow cathode plate flow channel groove (102) and cathode plate ridges (101) on both sides thereof on the cooling water flow field side.

5. The fuel cell bipolar plate flow field structure according to claim 2, characterized in that: The depth of the deeper cathode plate flow channel groove (102) ranges from 0.3 to 0.5 mm, and the depth of the shallower cathode plate flow channel groove (102) ranges from 0.2 to 0.3 mm.

6. The fuel cell bipolar plate flow field structure according to claim 5, characterized in that: The widths of two adjacent cathode plate flow channel grooves (102) are the same; the widths and heights of two adjacent cathode plate ridges (101) are the same.

7. The fuel cell bipolar plate flow field structure according to claim 2, characterized in that: The width of the narrower anode plate ridge (201) is in the range of 0.5-1.0 mm, and the width of the wider anode plate ridge (201) is in the range of 0.6-1.2 mm; the depth of the anode plate flow channel groove (202) is in the range of 0.2-0.35 mm.

8. The fuel cell bipolar plate flow field structure according to claim 7, characterized in that: The heights of two adjacent anode plate ridges (201) are the same; the widths and depths of two adjacent anode plate flow channel grooves (202) are the same.

9. The fuel cell bipolar plate flow field structure according to claim 1, characterized in that: The processing methods of the cathode monopolar plate (1) and the anode monopolar plate (2) include stamping, molding and etching.

10. A fuel cell stack comprising bipolar plates and membrane electrodes stacked in series, characterized in that: The bipolar plate is the fuel cell bipolar plate flow field structure as described in any one of claims 1-7.

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