Bipolar plate and cell stack

Abstract

Provided are a bipolar plate and a cell stack. The bipolar plate comprises a plate body; the plate body comprises an anode surface and a cathode surface; the anode surface and the cathode surface are each provided with a flow field area; the flow field area of the anode surface is provided with an anode gas flow field area and an anode surface cooling flow channel area; the flow field area of the cathode surface is provided with a cathode gas flow field area and a cathode surface cooling flow channel area; the anode surface cooling flow channel area and the cathode surface cooling flow channel area are communicated with each other; and when a plurality of bipolar plates are stacked, the anode surface cooling flow channel areas and the cathode surface cooling flow channel areas of every adjacent plate bodies are correspondingly communicated with each other. By means of the design of three flow fields on one plate, the anode gas flow field area, the cathode gas flow field area, and the cooling flow channel areas can be realized by means of the plate body; and by stacking plate bodies, the cooling flow channel areas are communicated with each other, thereby greatly reducing the thickness of the bipolar plate and the cell stack, reducing costs.

Description

Bipolar plates and stacks Technical Field

[0001] The present invention relates to the technical field of bipolar plates, and more particularly to a bipolar plate and a battery stack. In particular, it preferably relates to a horizontal heat-conducting, one-plate, three-field ultra-thin flexible graphite bipolar plate. Background Art

[0002] Thinning bipolar plates is crucial for increasing the volumetric power density of fuel cells. Typically, bipolar plate designs combine anode and cathode monopolar plates to form a two-plate, three-field structure. To reduce the thickness of these two-plate, three-field bipolar plates, industry solutions typically employ material-focused approaches such as process improvements and material modifications to thin the substrate. Additionally, thinning of bipolar plates can be achieved through design improvements, such as interlocking anode and cathode cooling cavities and troughs.

[0003] The Chinese invention patent document with publication number CN115954496A discloses a flexible graphite bipolar plate, comprising: a main plate body, a corrugated plate groove is provided in the middle thereof, and a through-port group is provided on both sides of the main plate body; and a plate assembly, which includes an upper plate and a lower plate of the same shape and size, and the upper and lower plates are coated with adhesive and are respectively attached to the front and back sides of the main plate body, and a notch group is provided on both sides of the upper plate, and the notch group is correspondingly connected to the through-port group.

[0004] Chinese invention patent publication CN109921051A discloses an ultra-thin flexible graphite bipolar plate and its preparation method. The flexible graphite bipolar plate comprises two upper and lower flexible graphite plates, with a graphene film interlayer between them. The graphene film is sandwiched between the two flexible graphite plates, forming a flexible graphite-based bipolar plate structure with a graphene film core. This document utilizes this flexible graphite bipolar plate structure with a graphene film core to improve the design of graphite bipolar plates.

[0005] Chinese invention patent publication CN111916782A discloses a rapidly cold-pressed, ultra-thin graphite composite bipolar plate base material and its preparation method. The base material and raw materials are composed by weight of: 40-60% 150-200 mesh natural flake graphite powder, 5-20% 100-150 mesh graphite worms, 5-15% 200-300 mesh graphite worms, 15-35% synthetic resin, and 1-3% surfactant. This document improves the graphite bipolar plate material by varying the components and raw material percentages of the graphite composite bipolar plate.

[0006] Chinese invention patent publication CN113224339A discloses a flexible, ultra-thin graphite bipolar plate and its preparation method. The preparation method comprises: providing a graphite powder material comprising expanded graphite, carbon fibers, carbon nanotubes, and a low-viscosity liquid binder; providing a carbon nanotube film and roughening the surface of the carbon nanotube film using physical or chemical methods; applying graphite powder layers on both sides of the carbon nanotube film, and combining the two graphite powder layers with the carbon nanotube film using hot pressing to form a flexible, ultra-thin graphite bipolar plate. This document improves the materials and process of graphite bipolar plates by modifying materials such as graphite powder and performing processes such as roughening and hot pressing.

[0007] Chinese invention patent publication CN115472859A discloses a graphite bipolar plate material with high airtightness and strength, a method for manufacturing the same, and the graphite bipolar plate. The graphite bipolar plate material comprises an aluminum-magnesium alloy phase and a graphite matrix, with the aluminum-magnesium alloy phase embedded within the pores of the graphite matrix via high-pressure injection. This document improves the material and process of the graphite bipolar plate by modifying the graphite bipolar plate material and employing a high-pressure injection process.

[0008] The two-plate three-field bipolar plate includes an anode plate and a cathode plate; the front of the anode plate is provided with an anode gas flow field area; the back of the anode plate is provided with an anode plate cooling flow channel groove; the front of the cathode plate is provided with a cathode gas flow field area, and the back of the cathode plate is provided with a cathode plate cooling flow channel groove, and the anode plate cooling flow channel groove and the cathode plate cooling flow channel groove form a cooling flow channel cavity accordingly. When the two-plate three-field bipolar plate is in use, the bipolar plates are stacked, and can be stacked in groups of two, three, four, etc. MEA is used between adjacent bipolar plates to separate the cathode gas flow field area and the anode gas flow field area. The cathode gas flow field area and the anode gas flow field area are respectively located on both sides of the MEA, forming a bipolar plate stack (including multiple bipolar plates and MEA). A cathode plate, an MEA, and an anode plate constitute a single cell. The series connection of multiple single cells is a battery stack. Due to the manufacturing characteristics of graphite bipolar plates, a cathode plate and an anode plate are usually bonded together to form a bipolar plate, and then an MEA is attached to one side to form a single cell. However, this single cell is actually a battery with half a cycle.

[0009] Regarding the above-mentioned related technologies, the inventor believes that the above-mentioned two-plate three-field bipolar plate has a cooling flow channel cavity formed between the anode plate and the cathode plate, and the anode gas flow field area and the cathode gas flow field area are respectively located on both sides of the bipolar plate. The anode plate and the cathode plate work together to form a bipolar plate, which requires at least two monopolar plates to be combined. The design thinning is difficult, and stacking multiple bipolar plates makes the bipolar plate stack thicker. The above-mentioned patent documents mainly thin the graphite plates through design improvements, process improvements or material modifications, but the thickness of the bipolar plates is still relatively thick; the cost is high after material modification.

[0010] Summary of the Invention

[0011] In view of the defects in the prior art, an object of the present invention is to provide a bipolar plate and a battery stack.

[0012] A bipolar plate provided according to the present invention includes a plate body;

[0013] The plate body includes an anode surface and a cathode surface;

[0014] The anode surface and the cathode surface are both provided with flow field areas;

[0015] The flow field area of ​​the anode surface is provided with an anode gas flow field area and an anode surface cooling flow channel area;

[0016] The cathode surface flow field area is provided with a cathode gas flow field area and a cathode surface cooling flow channel area;

[0017] The anode surface cooling channel area and the cathode surface cooling channel area are connected;

[0018] When a plurality of bipolar plates are stacked, the anode surface cooling channel areas and the cathode surface cooling channel areas between adjacent plates are correspondingly connected.

[0019] Preferably, the plate body is provided with an anode gas common channel hole and a cathode gas common channel hole;

[0020] When a plurality of bipolar plates are stacked, the anode gas common channel holes on the stacked plates form an anode gas common channel, and the cathode gas common channel holes on the stacked plates form a cathode gas common channel;

[0021] The anode gas common channel is connected to the anode gas flow field area;

[0022] The cathode gas common channel is connected to the cathode gas flow field area.

[0023] Preferably, a gas distribution area is provided on the anode surface and the cathode surface respectively;

[0024] The gas distribution area on the anode surface is connected to the anode gas flow field area;

[0025] The gas distribution area on the cathode surface is connected to the cathode gas flow field area.

[0026] Preferably, the anode surface cooling channel area includes an anode surface cooling channel groove and an anode surface cooling liquid common channel hole;

[0027] The cathode surface cooling channel area includes cathode surface cooling channel grooves and cathode surface cooling liquid common channel holes;

[0028] The anode surface cooling liquid common channel hole and the cathode surface cooling liquid common channel hole are in communication;

[0029] When a plurality of bipolar plates are stacked, the anode surface cooling liquid common channel holes and the cathode surface cooling liquid common channel holes between adjacent plates are connected;

[0030] The anode surface cooling channel grooves and the cathode surface cooling channel grooves between adjacent plates are connected to each other to form a cooling channel cavity;

[0031] The anode surface cooling liquid common channel holes and the cathode surface cooling liquid common channel holes of the stacked plates together constitute a cooling liquid common channel;

[0032] The cooling liquid common channel is connected to the cooling channel cavity.

[0033] Preferably, the anode surface cooling liquid common channel hole is arranged in the anode surface cooling channel groove;

[0034] The cathode surface cooling liquid common channel hole is arranged in the cathode surface cooling channel groove.

[0035] Preferably, the anode surface cooling channel area includes anode surface cooling liquid common channel holes;

[0036] The cathode surface cooling channel area includes cathode surface cooling liquid common channel holes;

[0037] The anode surface cooling liquid common channel hole and the cathode surface cooling liquid common channel hole are in communication;

[0038] When a plurality of bipolar plates are stacked, the anode surface cooling liquid common channel holes and the cathode surface cooling liquid common channel holes between adjacent plates are connected.

[0039] Preferably, the anode surface cooling channel area further includes anode surface cooling slot openings;

[0040] The cathode surface cooling flow channel area also includes cathode surface cooling slot openings;

[0041] The anode surface cooling groove opening is connected and arranged in the anode surface cooling flow channel groove;

[0042] The cathode surface cooling slot opening is connected and arranged in the cathode surface cooling channel slot;

[0043] The anode surface cooling slot opening is connected to the cathode surface cooling slot opening.

[0044] Preferably, the gas flow field of the anode gas flow field region is wavy or straight;

[0045] The gas flow field in the cathode gas flow field area is wavy or straight.

[0046] Preferably, the flow field area on the anode surface and the flow field area on the cathode surface are both provided with sealing grooves;

[0047] The sealing grooves are respectively arranged around the anode surface cooling channel area and the cathode surface cooling channel area.

[0048] According to the present invention, a battery stack is provided, comprising a plurality of bipolar plates and separators;

[0049] The bipolar plates are stacked;

[0050] The separator is arranged between the anode gas flow field area and the cathode gas flow field area, and is used to separate the anode gas flow field area and the cathode gas flow field area;

[0051] An anode gas flow channel is formed between the separator and the anode gas flow field area;

[0052] A cathode gas flow channel is formed between the separator and the cathode gas flow field area. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0054] Figure 1 is a schematic diagram of a "one plate, three fields" straight-flow bipolar plate design where the coolant flows along the flow field direction;

[0055] FIG2 is a partial enlarged schematic diagram of the dotted line portion in FIG1 ;

[0056] Figure 3 is a schematic diagram of a "one plate, three fields" straight flow bipolar plate design where the coolant flows perpendicular to the flow field direction;

[0057] FIG4 is a partial enlarged schematic diagram of the dotted line portion in FIG3 ;

[0058] FIG5 is a schematic diagram of a bipolar plate design with a "one plate, three fields" direct current path and mixed coolant flow;

[0059] FIG6 is a partial enlarged schematic diagram of the dotted line portion in FIG5 ;

[0060] FIG7 is a schematic diagram of a “one plate, three fields” wavy flow channel bipolar plate design in which the coolant flows perpendicular to the flow field direction;

[0061] FIG8 is a partial enlarged schematic diagram of the dotted line portion in FIG7 ;

[0062] Figure 9 is a schematic diagram of a “one plate, three fields” bipolar plate combination.

[0063] Figure numerals: "One plate, three cooling cavities, slots 3033" direct flow bipolar plate 1011 with coolant flowing along the flow field direction; common air channel 1021; "One plate, three fields" wavy flow channel bipolar plate 4011 with coolant flowing perpendicular to the flow field direction; common hydrogen channel 1022; membrane coated with catalytic layer 5011; common coolant channel 1023; gas diffusion layer 5012; gas distribution area 1031; seal 5021 in the sealing groove; gas flow field area 1032; bipolar plate 5031 in the fuel cell stack; cooling cavity 1033; heat conduction plane of the cooling groove 5032; cooling cavity sealing groove structure 1034; cooling cavity 5033 formed by two bipolar plates; "One plate, three fields" direct flow bipolar plate 2011 with coolant flowing perpendicular to the flow field direction; "One plate, three fields" direct flow cathode gas flow field 5035 with mixed coolant flow Bipolar plate 3011 DETAILED DESCRIPTION

[0064] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0065] Embodiment 1 of the present invention discloses a horizontally heat-conducting, one-plate, three-field ultra-thin flexible graphite bipolar plate, as shown in Figures 1 and 2. The plate comprises a plate body, including an anode surface and a cathode surface; both the anode surface and the cathode surface are provided with flow fields; the anode surface flow field comprises an anode gas flow field and an anode surface cooling channel; the cathode surface flow field comprises a cathode gas flow field and a cathode surface cooling channel; the anode surface cooling channel and the cathode surface cooling channel are interconnected; and when multiple bipolar plates are stacked, the anode surface cooling channel and the cathode surface cooling channel between adjacent plates are interconnected. The anode gas can be hydrogen, and the cathode gas can be air. This bipolar plate is a "one-plate, three-field" straight-flow bipolar plate 1011, in which the coolant flows along the flow field direction. This bipolar plate is a graphite bipolar plate. The gas flow field 1032 comprises an anode gas flow field and a cathode gas flow field.

[0066] There may be multiple anode gas flow fields and multiple anode surface cooling channel regions, and the anode gas flow fields and the anode surface cooling channel regions are uniformly distributed and interspersed in parallel with the anode surface flow field region. There may be multiple cathode gas flow fields and multiple cathode surface cooling channel regions, and the cathode gas flow fields and the cathode surface cooling channel regions are uniformly distributed and interspersed in parallel with the cathode surface flow field region. Each anode gas flow field region includes multiple uniformly distributed anode gas flow channel grooves; each cathode gas flow field region includes multiple uniformly distributed cathode gas flow channel grooves.

[0067] The plates are provided with anode gas common channel holes and cathode gas common channel holes. When multiple bipolar plates are stacked, the anode gas common channel holes on the stacked plates form an anode gas common channel, and the cathode gas common channel holes on the stacked plates form a cathode gas common channel. The anode gas common channel connects to the anode gas flow field, while the cathode gas common channel connects to the cathode gas flow field. The cathode gas common channel is an air common channel 1021. The anode gas common channel is a hydrogen common channel 1022.

[0068] The anode gas common channel holes are respectively located on both sides of the flow field area along the length direction; the cathode gas common channel holes are respectively located on both sides of the flow field area along the length direction; the connecting lines between the anode gas common channel holes and the connecting lines between the cathode gas common channel holes intersect.

[0069] Gas distribution areas 1031 are provided on the anode and cathode surfaces, respectively. The anode gas distribution area 1031 is connected to the anode gas flow area, while the cathode gas distribution area 1031 is connected to the cathode gas flow area. Gas distribution areas 1031 are located on either side of the flow area, between the gas channel holes (the anode gas common channel hole and the cathode gas common channel hole) and the flow area.

[0070] The anode surface cooling channel region includes an anode surface cooling channel groove and an anode surface coolant common channel hole. There can be two anode surface coolant common channel holes, located at either end of the anode surface cooling channel groove along its length. The cathode surface cooling channel region includes a cathode surface cooling channel groove and a cathode surface coolant common channel hole. There can be two cathode surface coolant common channel holes, located at either end of the cathode surface cooling channel groove along its length. The anode surface coolant common channel hole and the cathode surface coolant common channel hole are connected.

[0071] When multiple bipolar plates are stacked, the anode and cathode cooling channel holes between adjacent plates are connected; the anode and cathode cooling channel grooves between adjacent plates are connected to form a cooling channel cavity; the anode and cathode cooling channel holes of the stacked plates together form a cooling channel 1023; and the anode and cathode cooling channel holes at each end are connected to form a cooling channel 1023. Cooling channel 1023 is connected to the cooling channel cavity (cooling cavity 1033).

[0072] The anode surface cooling liquid common channel hole is connected and arranged in the anode surface cooling channel groove; the cathode surface cooling liquid common channel hole is connected and arranged in the cathode surface cooling channel groove.

[0073] As shown in Figures 5 and 6, the anode surface cooling channel area also includes anode surface cooling slot openings; the cathode surface cooling channel area also includes cathode surface cooling slot openings; the anode surface cooling slot openings are connected and arranged in the anode surface cooling channel slot; the cathode surface cooling slot openings are connected and arranged in the cathode surface cooling channel slot; the anode surface cooling slot openings and the cathode surface cooling slot openings are each one or more. In the stacked plate body, the cathode surface cooling slot openings and the cathode surface cooling slot openings are distributed in a straight line in the stacking direction. The anode surface cooling slot openings are connected to the cathode surface cooling slot openings. As shown in Figure 5, at this time, the bipolar plate is a "one plate, three fields" direct current bipolar plate 3011 with mixed coolant flow. At this time, the cooling slot openings are slots 3033 in the cooling cavity.

[0074] The gas flow field in the anode gas flow field is either wavy or linear; the gas flow field in the cathode gas flow field is either wavy or linear. As shown in Figures 7 and 8, the gas flow field is wavy; in this case, the bipolar plate is a "one plate, three fields" wavy flow channel bipolar plate 4011, where the coolant flows perpendicular to the flow field direction. As shown in Figures 1 and 2, the gas flow is linear; in this case, the bipolar plate is a "one plate, three fields" straight flow channel bipolar plate 1011, where the coolant flows along the flow field direction.

[0075] The anode and cathode flow fields are both provided with sealing grooves (cooling chamber sealing groove structures 1034); these grooves surround the anode and cathode cooling flow channel regions, respectively. These grooves accommodate seals (seals 5021 within the grooves, as shown in FIG9 ). These seals can be made of PIB glue, silicone rubber, or fluororubber.

[0076] The present invention discloses a design method for a horizontal heat-conducting one-plate-three-field ultra-thin flexible graphite plate, which belongs to the field of fuel cells. By utilizing the high horizontal heat conduction characteristics of flexible graphite, a cooling zone is set between the plate mainstream field (gas flow field area 1032) to cool the plate, thereby eliminating the cooling cavity formed by the commonly used anode and cathode monopolar plates. Through the design of a flexible graphite plate with one plate and three fields, a significant thinning of the bipolar plate is achieved. Mainstream field is a general term in the field of fuel cell plates. The mainstream field of a fuel cell refers to the flow field structure of the internal body, and the part outside the mainstream field is the transition zone (or distribution zone).

[0077] Flexible graphite is different from other bipolar plate materials. Because its graphite phase microstructure presents a continuous layered structure in the horizontal direction, the material has significant anisotropy, that is, the thermal conductivity and electrical conductivity in the horizontal direction are much higher than those in the vertical direction. Compared with other bipolar plate materials (such as metal materials, composite plate graphite materials, etc.), flexible graphite has a significant advantage in horizontal thermal conductivity, which makes it possible to use the horizontal thermal conductivity of the material to cool the plate. The thickness of existing bipolar plates generally exceeds 0.8mm. In order to achieve an ultra-thin graphite bipolar plate with a thickness of less than 0.6mm, a one-plate three-field flow field design is used to achieve horizontal cooling of the plate, thereby achieving the purpose of significantly reducing the thinning of the bipolar plate and significantly reducing the amount of material used.

[0078] The one-plate, three-field bipolar plate design can not only significantly reduce the thickness, but also significantly reduce material usage and greatly reduce material and process costs.

[0079] As shown in FIG1 , the coolant enters the bipolar plate from the common channel perpendicular to the gas flow field, and then flows along the gas flow direction to cool the plate.

[0080] As shown in Figure 5, the coolant enters the bipolar plate through a common channel perpendicular to the gas flow field, then flows along the gas flow path to cool the plates. As the coolant passes through the slots in the cooling cavity 1033, the coolant flow is redistributed, optimizing its flow.

[0081] As can be seen in FIG7 , the coolant enters the bipolar plate directly from the cooling channel perpendicular to the gas flow field to cool the plate.

[0082] The second embodiment of the present invention also discloses a bipolar plate, as shown in Figures 3 and 4. This differs from the first embodiment in that the anode cooling channel region includes a common anode coolant channel hole; the cathode cooling channel region includes a common cathode coolant channel hole; and the anode and cathode coolant channels are interconnected. This bipolar plate is a "one-plate, three-field" straight-flow bipolar plate 2011, in which the coolant flows perpendicular to the flow field.

[0083] When multiple bipolar plates are stacked, the anode and cathode cooling channels between adjacent plates are connected. The anode and cathode cooling channels of the stacked plates together form a cooling channel 1023.

[0084] As can be seen in FIG2 , the coolant enters the bipolar plate directly from the cooling channel perpendicular to the gas flow field to cool the plate.

[0085] The third embodiment of the present invention also discloses a fuel cell stack, as shown in FIG9 , comprising a plurality of bipolar plates (bipolar plates 5031 in the fuel cell stack) and a separator; the bipolar plates are stacked; the separator is disposed between the anode gas flow field region and the cathode gas flow field region to separate the anode gas flow field region from the cathode gas flow field region; an anode gas flow channel is formed between the separator and the anode gas flow field region (anode gas flow channel groove); and a cathode gas flow channel is formed between the separator and the cathode gas flow field region (cathode gas flow channel groove). There may be multiple anode gas flow channels and cathode gas flow channels, with the anode gas common channel connecting to the anode gas flow channel groove; and the cathode gas common channel connecting to the cathode gas flow channel groove. The separator comprises a membrane 5011 (CCM) coated with a catalyst layer and a gas diffusion layer 5012 (GDL). The gas diffusion layer 5012 is respectively arranged on both sides of the membrane 5011 coated with the catalyst layer. The gas diffusion layer 5012 blocks the notch of the cathode gas flow channel groove to form a cathode gas flow field 5035 (cathode gas flow channel). The gas diffusion layer 5012 blocks the notch of the anode gas flow channel groove to form an anode gas flow field 5034 (anode gas flow channel). The membrane 5011 coated with the catalyst layer respectively contacts the seals on both sides. The cooling flow channel cavity formed between adjacent plates is a cooling cavity 5033 formed by two bipolar plates, and the membrane 5011 coated with the catalyst layer is respectively located between the cooling cavity 5033 formed by the two bipolar plates. The bottom of the cooling flow channel groove is the heat conducting plane 5032 of the cooling groove (that is, the upper and lower surfaces of the cooling cavity 5033 formed by the two bipolar plates). The fixation between the bipolar plates is a common practice in the industry, and is fixed by friction and positive pressure. The full name of CCM in English is catalyst-coated membrane, which is a common term in the industry. The full English name of GDL is gas diffusion layer, which is a common term in the industry.

[0086] Figure 9 is a schematic diagram of a bipolar plate combination, taking a "one plate, three fields" straight channel bipolar plate in which the coolant flows along the flow field direction as an example. It can be seen from the figure that due to the high thermal conductivity of flexible graphite in the horizontal direction, the reaction heat in the mainstream field is conducted horizontally through the plate to the cooling cavity 1033, thereby realizing the cooling of the fuel cell stack.

[0087] The present invention defines the main flow field area between the two cooling slots as a flow field module, and the cooling slots including the sealing area as a cooling module. Compared to bipolar plates with a two-plate, three-field design, this invention uses nearly half the plate material, significantly reducing bipolar plate costs.

[0088] Embodiment 4 of the present invention also discloses a bipolar plate with a total length of 430 mm and a width of 200 mm (the mainstream field area is 350 mm long and 175 mm wide, and the gas flow field direction is designed along the length direction of the plate), a straight channel "one plate three fields" flexible graphite bipolar plate with a thickness of 0.55 mm, and a cooling channel designed to flow along the direction of the gas flow field (corresponding to Figure 1), and the coolant flows along the flow field direction.

[0089] The cathode gas flow field has a groove depth of 0.35mm, a groove width of 0.8mm, and a ridge width of 0.4mm. The ridge is the portion of the flow field that contacts the GDL. The anode and cathode flow fields are staggered, with the anode gas flow field groove depth of 0.35mm, a groove width of 0.6mm, and a ridge width of 0.6mm. The overall plate structure has a draft angle of 15°. The draft angle is the angle of inclination between the flow groove and the ridge, a common term in the industry. The material thickness at the cathode and anode plate ridges is 0.2mm. The common coolant channel 1023 is 4.6mm wide and 15mm long. The cooling cavity 1033 is 0.4mm deep, corresponding to a 0.15mm thickness on the heat-conducting surface of the cooling groove. The cooling cavity 1033 is 4.6mm wide. The gas flow field center-to-center distance is 1.2mm. Every 12 cathode or anode gas flow channels form a flow field module. The sealing groove area is 3mm per side, meaning the total width of each module is 20.4mm. The total width of a single cooling cavity and single flow field module is 25mm. Two half-block gas flow field modules (a half-block gas flow field module consists of six cathode or anode gas flow channels) are distributed on both sides of the entire electrode plate along the width direction. Inward along the width direction, there are six gas flow field modules and seven cooling modules. The MEA (membrane electrode assembly) has a borderless design at the cooling groove, that is, the MEA in this area is discontinuous, but the MEA in gas distribution area 1031 is a continuous design. The bipolar plates and MEAs form a single battery unit, which is repeatedly stacked to form a battery stack.

[0090] Embodiment 5 of the present invention also discloses a bipolar plate with a total length of 380 mm and a width of 250 mm (the length of the mainstream field area is 360 mm and the width is 180 mm, and the gas flow field direction is designed along the width direction of the plate), a wavy flow channel "one plate three fields" flexible graphite bipolar plate with a thickness of 0.5 mm, and a cooling channel designed to flow along the direction of the gas flow field, and the coolant flows in a mixed manner.

[0091] The wave channel has a 25° inclination angle, and the angle between the wave flow field and the DC field is the wave channel inclination angle. The cathode gas flow field has a groove depth of 0.34mm, a groove width of 0.85mm, and a ridge width of 0.35mm. The anode and cathode flow fields are staggered, with the anode gas flow field groove depth of 0.3mm, a groove width of 0.6mm, and a ridge width of 0.6mm. The overall plate structure has a draft angle of 10°. The material thickness at the cathode ridge of the plate is 0.16mm, and the material thickness at the anode ridge is 0.2mm. The coolant common channel 1023 is 4.8mm wide and 15mm long. The slot 3033 in the cooling cavity is 4.8mm wide and 10mm long. Three slots 3033 in the cooling cavity are evenly distributed along the cooling cavity 1033, with a spacing of 40mm. The cooling cavity 1033 is 0.4mm deep, corresponding to a 0.15mm thickness of the cooling groove heat conduction surface, and the cooling cavity width is 4.8mm. The center distance of the gas flow field is 1.2mm, and every 16 cathode or anode gas flow channels form a flow field module. The single side of the sealing groove area is 3mm, that is, the total width of each module is 25.2mm, and the total width of the single cooling cavity and the single flow field module is 30mm. The two half-block gas flow field modules (the half-block gas flow field module consists of 8 cathode or anode gas flow channels) are distributed on both sides of the entire plate along the length direction. Inward along the length direction, there are 11 gas flow field modules and 12 cooling modules. The MEA has a borderless design at the cooling groove, that is, the MEA in this area is discontinuous, but the MEA in the gas distribution area 1031 is a continuous design. The bipolar plate and MEA form a single battery unit, which is repeatedly stacked to form a battery stack. The design of the cooling channel along the width direction of the plate can reduce the cooling path and improve the cooling effect.

[0092] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0093] Compared with the prior art, the present invention has the following beneficial effects:

[0094] 1. The present invention adopts a one-plate, three-field design, which allows the plate to contain the anode gas flow field area, the cathode gas flow field area, and the cooling channel area. By stacking the plates, the cooling channel areas are interconnected, which greatly reduces the thickness of the bipolar plates and the stack, thereby reducing costs.

[0095] 2. When the plates are stacked, the present invention seals the plates by embedding a sealant into the sealing groove, thereby effectively improving the sealing performance of the bipolar plates and the stack.

[0096] 3. In the present invention, the anode gas and cathode gas are distributed through the gas distribution area and then enter the cathode gas flow field area and the anode gas flow field area respectively; thus, the gas uniformity of the cathode gas flow field area and the anode gas flow field can be improved.

[0097] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A bipolar plate, characterized in that: Including the board body; The plate body comprises an anode surface and a cathode surface; The anode surface and the cathode surface are both provided with flow field areas; The flow field area of ​​the anode surface is provided with an anode gas flow field area and an anode surface cooling flow channel area; The cathode surface flow field area is provided with a cathode gas flow field area and a cathode surface cooling flow channel area; The anode surface cooling channel area and the cathode surface cooling channel area are connected and arranged; When a plurality of the bipolar plates are stacked, the anode surface cooling channel areas and the cathode surface cooling channel areas between adjacent plates are connected to each other.

2. The bipolar plate according to claim 1, characterized in that: The plate body is provided with an anode gas common channel hole and a cathode gas common channel hole; When a plurality of the bipolar plates are stacked, the anode gas common channel holes on the stacked plates form an anode gas common channel, and the cathode gas common channel holes on the stacked plates form a cathode gas common channel; The anode gas common channel is connected to the anode gas flow field area; The cathode gas common channel is connected to the cathode gas flow field area.

3. The bipolar plate according to claim 1, characterized in that: The anode surface and the cathode surface are respectively provided with a gas distribution area (1031); The gas distribution area (1031) on the anode surface is connected to the anode gas flow field area; The gas distribution area (1031) on the cathode surface is connected to the cathode gas flow field area.

4. The bipolar plate according to claim 1, characterized in that: The anode surface cooling channel area includes an anode surface cooling channel groove and an anode surface cooling liquid common channel hole; The cathode surface cooling channel area includes cathode surface cooling channel grooves and cathode surface cooling liquid common channel holes; The anode surface cooling liquid common channel hole is connected to the cathode surface cooling liquid common channel hole; When a plurality of bipolar plates are stacked, the anode surface cooling liquid common channel holes and the cathode surface cooling liquid common channel holes between adjacent plates are connected; The cooling channel grooves on the anode surface and the cooling channel grooves on the cathode surface between adjacent plates are connected to each other to form a cooling channel cavity; The cooling liquid common channel holes on the anode side and the cooling liquid common channel holes on the cathode side of the stacked plates together constitute a cooling liquid common channel (1023); The cooling liquid common channel (1023) is connected to the cooling channel cavity.

5. The bipolar plate according to claim 4, characterized in that: The anode surface cooling liquid common channel hole is connected and arranged in the anode surface cooling channel groove; The cathode surface cooling liquid common channel hole is arranged in the cathode surface cooling channel groove.

6. The bipolar plate according to claim 1, characterized in that: The anode surface cooling channel area includes anode surface cooling liquid common channel holes; The cathode surface cooling channel area includes cathode surface cooling liquid common channel holes; The anode surface cooling liquid common channel hole is connected to the cathode surface cooling liquid common channel hole; When a plurality of the bipolar plates are stacked, the anode surface cooling liquid common channel holes and the cathode surface cooling liquid common channel holes between adjacent plates are connected.

7. The bipolar plate according to claim 4, characterized in that: The anode surface cooling channel area also includes anode surface cooling slot openings; The cathode surface cooling flow channel area also includes cathode surface cooling slot openings; The anode surface cooling groove opening is connected and arranged in the anode surface cooling flow channel groove; The cathode surface cooling groove opening is connected and arranged in the cathode surface cooling flow channel groove; The anode surface cooling slot opening is connected to the cathode surface cooling slot opening.

8. The bipolar plate according to claim 1, characterized in that: The gas flow field of the anode gas flow field area is wavy or straight; The gas flow field in the cathode gas flow field area is wavy or straight.

9. The bipolar plate according to claim 1, characterized in that: The flow field area on the anode surface and the flow field area on the cathode surface are both provided with sealing grooves; The sealing grooves are respectively arranged around the anode surface cooling channel area and the cathode surface cooling channel area.

10. A battery stack, characterized in that: Comprising a plurality of bipolar plates and separators as described in any one of claims 1 to 9; The bipolar plates are stacked; The partition layer is arranged between the anode gas flow field area and the cathode gas flow field area, and is used to separate the anode gas flow field area and the cathode gas flow field area; An anode gas flow channel is formed between the separator and the anode gas flow field area; A cathode gas flow channel is formed between the separator and the cathode gas flow field area.

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