CN214625111U - Bipolar plate and single cell comprising same - Google Patents
Bipolar plate and single cell comprising same Download PDFInfo
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- CN214625111U CN214625111U CN202120992781.2U CN202120992781U CN214625111U CN 214625111 U CN214625111 U CN 214625111U CN 202120992781 U CN202120992781 U CN 202120992781U CN 214625111 U CN214625111 U CN 214625111U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
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Abstract
The utility model discloses a bipolar plate and monocell that contains it, wherein bipolar plate for fuel cell, bipolar plate include at least one gas flow channel that is used for the gas circulation, still have drainage channel on the bipolar plate, drainage channel has entrance point and exit end along the rivers direction, and the entrance point communicates in all gas flow channels, and drainage channel's exit end extends to gas flow channel's below and is linked together with bipolar plate's outside. The bipolar plate adopts the structure form, is beneficial to the discharge of liquid water in the bipolar plate and further prevents the liquid water from blocking the gas flow passage, so as to prevent the phenomenon that the gas flow amount flowing into the whole gas flow passage or a large section of gas flow passage is less due to water blocking and further influence the performance of the fuel cell. And the gas in the gas flow channel can also flow into different gas flow channels through the drainage channel, so that the flow distribution of the gas in different gas flow channels is realized, and the mass transfer effect of the bipolar plate is improved.
Description
Technical Field
The utility model relates to a fuel cell field, in particular to bipolar plate and monocell that contains it.
Background
A fuel cell is a power generation system that directly converts chemical energy into electrical energy in a fuel cell stack using an electrochemical process. The fuel cell can be applied not only to industrial, household electric appliances and vehicles but also to power supplies of small-scale electric and electronic devices such as portable devices.
The main core components of the fuel cell are a membrane electrode and a bipolar plate, wherein the membrane electrode mainly comprises a catalyst layer, a diffusion layer, a proton exchange membrane and the like, and the bipolar plate is divided into a cathode bipolar plate and an anode bipolar plate. When the fuel cell is operated, fuel gas passes through the anode bipolar plate, oxidant passes through the cathode bipolar plate, and electrochemical reaction occurs on both sides of the membrane electrode. When the fuel cell is operated in a high-current high-power state, a large amount of fuel gas and oxidant gas are required to enter the membrane electrode of the fuel cell, while a large amount of water produced by the electrochemical reaction is discharged from the membrane electrode. If the fuel gas and oxidant gas required by the electrochemical reaction of the fuel cell cannot be timely fed into the membrane electrode and the tail gas and generated water of the fuel cell cannot be timely discharged out of the membrane electrode, mass transfer polarization and flooding of the fuel cell can occur, which affects further improvement of the performance of the fuel cell and even degrades the performance of the fuel cell. Therefore, it is very important to improve the mass transfer capability and the water discharge capability inside the fuel cell for the fuel cell operated at high current and high power.
In the prior art, a plurality of trapezoidal convex parts are arranged in a channel groove of a flow channel, when gas flows from the upstream to the downstream of the flow channel and meets the convex parts arranged at the bottom of the flow channel, the cross section area of the flow channel is reduced, the flow speed is reduced, the pressure of the gas is improved, and the gas in the flow channel is pushed to a gas diffusion layer of a membrane electrode so as to enter an electrode, so that the mass transfer capacity of a fuel cell is improved, and the performance of the fuel cell is improved. However, with the adoption of the mode, the mass transfer capacity of the gas is only enhanced, the problem of liquid water drainage is not solved, and if the liquid water cannot be drained in time, a flow channel is easily blocked, so that the mass transfer is influenced, and even the water flooding is caused.
Certainly, the flow channel groove is arranged in a step form, and the variable cross-section flow channel can disturb the flow of the reaction gas, so that the gas flowing through the flow channel generates turbulent flow, and the diffusion capacity of the gas is enhanced; the cathode bipolar plate adopts a structure that the depth of the middle flow channel is greater than that of the outer flow channel, so that the uneven flow velocity distribution caused by different paths of oxygen transmitted to the flow channel inlet through the transition region via the oxygen inlet can be eliminated, the power density uniformity of each area of the polar plate is improved, and the drainage of the flow channel is enhanced. However, with this structure, there are problems that the structure is complicated, and the matching between the anode side bipolar plate and the cathode side bipolar plate is limited.
In summary, the prior art improves the mass transfer uniformity of fuel cells by different technical means, and the drainage of the fuel cell system still relies on the reactant gas to sweep the liquid water out of the bipolar plate. But the situation that the bipolar plate is blocked or even flooded due to poor drainage performance still exists.
SUMMERY OF THE UTILITY MODEL
The to-be-solved technical problem of the utility model is to provide a bipolar plate and contain its monocell in order to overcome the defect such as bipolar plate drainage performance among the fuel cell pile among the prior art is poor.
The utility model discloses an above-mentioned technical problem is solved through following technical scheme:
a bipolar plate for a fuel cell, the bipolar plate having at least one gas flow channel for conveying a reactant gas, the bipolar plate further having a water drainage channel, the water drainage channel having an inlet end and an outlet end along a water flow direction, the inlet end communicating with each of the gas flow channels, the outlet end of the water drainage channel extending below the gas flow channels and communicating with the outside of the bipolar plate.
In this embodiment, the drainage channel is used to drain the liquid water in the gas channels, and the inlet end of the drainage channel is connected to all the gas channels, so that the liquid water in each gas channel can flow into the drainage channel from the inlet end and be drained from the outlet end. The outlet end extends to the lower part of the gas flow channel and is communicated with the outside of the bipolar plate, so that liquid water in the bipolar plate passes through the drainage channel under the action of gravity and is discharged out of the bipolar plate from the outlet end of the drainage channel, the discharge of the liquid water in the bipolar plate is facilitated, the gas flow channel is prevented from being blocked by the liquid water, meanwhile, the phenomenon of gas shortage caused by the fact that the amount of gas flowing into the whole gas flow channel or a large section of gas flow channel is small due to the fact that the water is blocked is avoided, and the performance of a fuel cell is prevented from being influenced. In addition, because the inlet end of the drainage channel is communicated with the gas flow channel, the drainage performance of the bipolar plate is improved, and meanwhile, gas in the gas flow channel can flow into different gas flow channels through the drainage channel, so that the flow distribution of the gas in different gas flow channels is realized, and the mass transfer effect of the bipolar plate is improved. According to the technical scheme, the drainage performance and the mass transfer performance of the bipolar plate can be improved only by adding the drainage channel, so that the bipolar plate is simple in structure and low in production cost.
Preferably, the drain passage includes:
the confluence groove is arranged at the lower end of the reaction area of the bipolar plate and is spaced from the gas flow channel at the lowest part, the confluence groove extends along the flowing direction of the reaction gas, and the outlet end is positioned on the confluence groove;
the splitter box is communicated with the gas flow channel and the confluence groove.
In the scheme, liquid water in the gas flow channel flows into the confluence groove through the diversion groove and then is discharged out of the bipolar plate from the outlet end. And will converge the groove and set up the below at the gas flow channel of below for liquid water finally passes through the groove drainage of converging, prevents that the gas flow channel of below from being moved and play the effect that converges the groove, thereby is blockked up by liquid water, and then loses some reaction area. The confluence groove extends along the flow channel direction of the reaction gas, so that liquid water in the confluence groove is discharged from the outlet end under the pressure of the gas. The splitter box can discharge liquid water in the gas flow channel in time, and the gas flow channel is communicated with each other, so that even if a certain section of the gas flow channel is blocked, gas can flow into other unblocked gas flow channels through the splitter box, and the influence of blockage of the gas flow channel is reduced.
Preferably, the gas flow channels are direct flow channels or wave-shaped flow channels, the plurality of gas flow channels are arranged at intervals, a ridge is formed between two adjacent gas flow channels, each ridge is provided with a first groove, the first grooves are communicated with the two adjacent gas flow channels, and the flow channels after the first grooves are communicated with the gas flow channels are the diversion channels.
In this scheme, the structural style of the gas flow channels is not limited, and the gas flow channels may be straight flow channels or wave flow channels, wherein, as a preferred scheme, the gas flow channels are spaced and parallel to each other. Two adjacent gas channels form a ridge rising upward from the bottom of the gas channel. The first groove is arranged on the ridge, two adjacent gas flow channels are communicated through the first groove, so that liquid water in the gas flow channel positioned above can flow into the next gas flow channel downwards along the first groove, then flows into the next gas flow channel from the first groove on the next ridge until flowing into the confluence groove, and flows out of the bipolar plate from the outlet end of the confluence groove. The first groove has the function of discharging liquid water in the gas flow channel, and meanwhile, the two adjacent gas flow channels are communicated through the first groove, so that gas can be distributed to different gas flow channels from the gas flow channels.
Preferably, each of the ridges is provided with a plurality of first grooves spaced from each other, and the first grooves are distributed in an array on the bipolar plate. The plurality of first grooves are arranged on one ridge back, so that the drainage performance and the mass transfer performance of the bipolar plate can be further improved. The first grooves are distributed on the bipolar plate in an array mode, so that the water drainage balance and the mass transfer uniformity of the bipolar plate are improved, and the bipolar plate has the advantage of convenience in processing.
Preferably, the angle between the first groove and the extension direction of the ridge is in the range of 45-135 °. The liquid water can be discharged into the confluence groove along the first groove by setting the included angle between the first groove and the extension direction of the ridge within the range of 45-135 degrees. The ridges at different positions and the included angles between the first grooves at different positions of the same ridge and the flowing direction of the gas are not limited, and the included angles can be the same or different, as long as the communication between the adjacent gas channels can be realized. Preferably, the first groove is perpendicular to the extending direction of the ridge. On the one hand, the liquid water flows out along the first groove under the action of gravity, and on the other hand, the structure is simple and the processing is convenient. And is
The first grooves in the same row are in the same straight line. The first grooves on the same row are arranged on the same straight line, when liquid water in the gas flow channel is discharged from the first grooves under the action of gravity, the liquid water directly flows from the first grooves above to the first grooves below through the gas flow channel, flows into the confluence groove along the first grooves in sequence, and is discharged out of the galvanic pile. Therefore, the adoption of the structural form is beneficial to further improving the drainage performance of the bipolar plate.
Preferably, when the gas flow channel is a wave-shaped flow channel, the gas flow channel has a wave crest and a wave trough along the gas flow direction, and the first groove is disposed at the position of the wave trough. Because the trough is in the minimum of gas flow channel, liquid water easily collects in trough department, consequently sets up first recess in the position of trough, and liquid water in the gas flow channel can discharge along first recess after the crest of flowing to the trough along the gas flow channel from the gas flow channel under the effect of gravity to improve the drainage ability of gas flow channel, and then prevent that the phenomenon that the gas flow channel is blockked up in trough department from taking place, still have the characteristics that improve the homogeneity of bipolar plate's mass transfer simultaneously.
Preferably, the gas flow channel is a serpentine flow channel, and the diversion channel is communicated with a transverse part of the lower end of the gas flow channel. For the serpentine flow channel, the transverse part at the lower end is at the lowest point of the gas flow channel, liquid water is easy to collect at the lowest point, so that the diversion channel is communicated with the gas flow channel, and when the liquid water flows downwards to the position of the transverse part at the lower end along the vertical part of the gas flow channel, the liquid water can flow into the confluence channel from the diversion channel and is discharged out of the pile. It is advantageous to prevent the gas flow passage from being blocked at the lateral portion at the lower end by liquid water.
Preferably, a second groove is formed in the ridge between the vertical portions of the gas flow channels, and two ends of the second groove penetrate through the vertical portions of the gas flow channels on two sides of the ridge respectively. And a second groove is formed on the ridge between the vertical parts of the gas flow channel, so that the second groove is communicated with the two adjacent vertical parts, and gas can flow from one vertical part to the other vertical part of the gas flow channel through the second groove. Even if the bottom of the gas flow channel is blocked, mass transfer in other parts of the gas flow channel is not affected. Thus, the use of this structural form has the advantage of improving the mass transfer properties of the bipolar plate.
Preferably, the outlet end is communicated with a gas common outlet communicated with the gas flow channel, the bottom of the drainage channel is flush with the bottom of the gas flow channel, and the width of the drainage channel is not less than that of the gas flow channel. The bottoms of the splitter box and the confluence box are arranged to be flush with the bottom of the gas flow channel, so that the liquid water in the gas flow channel can be discharged, and the drainage performance of the bipolar plate can be further improved. The width of the drainage channel is set to be not less than that of the gas flow channel, so that the drainage of liquid water is facilitated. The outlet end of the drainage channel is communicated with the gas common outlet communicated with the gas flow channel, so that the structure is simple, a drainage port is not additionally arranged on the bipolar plate, and liquid water is drained under the pressure of reaction gas.
Preferably, a plurality of protruding portions are arranged at intervals in the gas flow channel at positions avoiding the water drainage channel, the protruding portions protrude from the bottom of the gas flow channel to a direction close to the membrane electrode plate, and the top surfaces of the protruding portions are lower than the top surfaces of the ridges on the two sides of the gas flow channel; and a coolant bridge is arranged on one side of the cooling surface of the bipolar plate, a third groove is formed at the position corresponding to the bulge, and two ends of the coolant bridge are respectively communicated with the third groove and a coolant inlet on the bipolar plate. Set up the bellying in gas flow path at interval for when gas passes through the position of bellying from gas flow path's ordinary section, gas takes place to deflect in the gas flow direction, produces the velocity component of perpendicular to gas diffusion layer, is favorable to reacting gas to the diffusion of gas diffusion layer, moreover, owing to set up the bellying, the cross-section of gas flow path diminishes, and the velocity of flow improves, also is favorable to taking away the liquid water of diffusion layer. The third groove formed by the bulge on the reaction surface is communicated with the coolant inlet through the coolant bridge hole to form a flow channel of the cooling liquid, so that the design of the cooling flow channel is simplified.
A cell characterized in that it comprises a bipolar plate as described above.
In this aspect, the use of the bipolar plate as described above in the cell can improve not only the drainage performance of the cell but also the mass transfer performance of the cell, and thus the performance of the cell.
On the basis of the common knowledge in the field, the above preferred conditions can be combined at will to obtain the preferred embodiments of the present invention.
The utility model discloses an actively advance the effect and lie in: the utility model provides a bipolar plate is through setting up the drainage channel who is linked together with gas flow channel on bipolar plate for the liquid water in each gas flow channel can both be discharged through drainage channel. The outlet end of the drainage channel extends to the lower part of the gas flow channel and is communicated with the outside of the bipolar plate, so that liquid water in the bipolar plate is discharged out of the bipolar plate from the outlet end through the drainage channel under the action of gravity, the discharge of the liquid water in the bipolar plate is facilitated, the gas flow channel is prevented from being blocked by the liquid water, meanwhile, the phenomenon of gas shortage caused by the fact that the amount of gas flowing into the whole gas flow channel or a large section of gas flow channel is small due to the fact that water is blocked can be prevented, and the performance of a fuel cell is further influenced. Moreover, because the drainage channel is communicated with the gas flow channel, the drainage performance of the bipolar plate is improved, and meanwhile, gas in the gas flow channel can flow into different gas flow channels through the drainage channel, so that the flow distribution of the gas in different gas flow channels is realized, and the mass transfer effect of the bipolar plate is improved. According to the scheme, the drainage performance and the mass transfer performance of the bipolar plate can be improved only by adding the drainage channel, the structure is simple, and the production cost is low.
Drawings
Fig. 1 is a schematic structural view of an anode-side bipolar plate according to embodiment 1 of the present invention.
Fig. 2 is a partially enlarged schematic structural view of an anode-side bipolar plate according to embodiment 1 of the present invention.
Fig. 3 is a partially enlarged schematic structural view of the case where the first groove in the anode-side bipolar plate of embodiment 1 of the present invention has the same groove depth as the gas flow channel.
Fig. 4 is a partially enlarged view of a bipolar plate according to embodiment 2 of the present invention in which the groove depth of the first groove is smaller than the groove depth of the gas flow channel.
Fig. 5 is a partially enlarged view of a bipolar plate according to embodiment 2 of the present invention, in which the groove depth of the first groove is the same as the groove depth of the gas flow channel.
Fig. 6 is a partially enlarged schematic view of a bipolar plate according to embodiment 3 of the present invention, in which no second groove is provided.
Fig. 7 is a partially enlarged view of a bipolar plate according to embodiment 3 of the present invention in the case where a second groove is provided in the bipolar plate.
Description of reference numerals:
Back 102
Upstream gas distribution section 60
Downstream gas distribution section 70
Detailed Description
The present invention will be more clearly and completely described below by way of examples and with reference to the accompanying drawings, but the present invention is not limited thereto.
The fuel cell system is a power generation system which takes a fuel cell stack as a core and consists of a fuel supply and circulation unit, an oxidant supply unit, a water management unit, a heat management unit, a control unit and the like. The fuel cell stack is formed by stacking a plurality of fuel cells in series. Each single cell comprises a proton exchange membrane, and a cathode/anode catalyst layer, a cathode/anode gas diffusion layer and a cathode/anode bipolar plate are symmetrically and sequentially arranged on two sides of the proton exchange membrane. The fuel cell stack is a place where electrochemical reactions occur, and is a core part of a fuel cell system. When the fuel cell stack works, hydrogen and oxygen are respectively distributed to the bipolar plates of each single cell through the main gas channels of the fuel cell stack, are guided by the bipolar plates and are uniformly distributed to the proton exchange membrane and are in contact with the catalyst to perform electrochemical reaction. The adjacent single cells are separated by bipolar plates, and the bipolar plates are used for connecting the front single cell and the rear single cell in series and providing a gas flow path of the single cells. The bipolar plate is a framework in a fuel cell stack, and plays roles of supporting, collecting current, providing channels for cooling liquid, separating an oxidant and a reducing agent and the like in the fuel cell. The structure of the bipolar plate directly influences the performances of the fuel cell such as water drainage, mass transfer, cooling and the like.
The following embodiments of the present invention are improvements made to the poor drainage performance and mass transfer performance of bipolar plates in the prior art. These specific embodiments are described in detail below.
Example 1
As shown in fig. 1 to 3, the present embodiment provides a bipolar plate for a fuel cell. Wherein, the two sides of the thickness direction of the bipolar plate are respectively a reaction surface and a cooling surface. The reaction surface is used for the circulation of reaction gas, and the cooling surface is used for the circulation of cooling liquid. A fuel gas inlet 20 and an oxidant gas inlet 30 are provided at one end of the bipolar plate in the longitudinal direction, and a fuel gas outlet 40 and an oxidant gas outlet 50 are provided at the other end. A sealant groove or sealant line 120 boss is disposed between the gas inlets and the gas outlets to prevent gas from being transmitted between the gas inlets or the gas outlets. After a plurality of single cells are stacked, the fuel gas inlets 20 in the bipolar plates form a fuel gas inlet common flow channel, the oxidant gas inlets 30 form an oxidant gas inlet common flow channel, and a fuel gas outlet common flow channel and an oxidant outlet common flow channel are also formed. The reaction zone 10 of the bipolar plate is located in the middle of the reaction face of the bipolar plate and the gas distribution zones are divided into an upstream gas distribution zone 60 and a downstream gas distribution zone 70. For an anode side bipolar plate, the upstream gas distribution region 60 communicates with both the fuel gas inlet 20 and the reaction zone 10, and the downstream gas distribution region 70 communicates with both the fuel gas outlet 40 and the reaction zone 10; for a cathode side bipolar plate, the upstream gas distribution section 60 communicates with both the oxidant gas inlet 30 and the reaction zone 10, and the downstream gas distribution section 70 communicates with both the oxidant gas outlet 50 and the reaction zone 10. With the above configuration, the flow path of the reaction gas is formed.
In this embodiment, a gas flow channel 101 formed by at least one concave-convex groove for gas circulation is disposed on the reaction surface of the bipolar plate, and at least one drain channel 103 different from the gas flow channel is further disposed on the bipolar plate, the drain channel 103 has an inlet end and an outlet end along the water flow direction (the direction indicated by the arrow in the figure), the inlet end is communicated with each gas flow channel, and the outlet end of the drain channel extends to the lower side of the gas flow channel and is communicated with the outside of the bipolar plate.
For the sake of easy understanding, the present embodiment will be described by taking bipolar plates on the anode side as an example. The drain channel is used for draining liquid water in the gas flow channels 101, and the inlet end of the drain channel is communicated with all the gas flow channels 101, so that the liquid water in each gas flow channel 101 can flow into the drain channel from the inlet end of the drain channel and can be drained out of the bipolar plate from the outlet end. And the outlet end extends below the gas flow channel 101 and communicates with the exterior of the bipolar plate so that the bipolar plate is discharged through the drain channel and out of the outlet end of the drain channel by gravity. By adopting the structure, the discharge of liquid water in the bipolar plate is facilitated, the gas flow channel 101 is prevented from being blocked by the liquid water, and meanwhile, the phenomenon of gas shortage or water flooding caused by less gas amount flowing into the whole gas flow channel 101 or the large-section gas flow channel 101 due to water blocking can be prevented, so that the performance of the fuel cell is prevented from being influenced. Moreover, because the inlet end of the drainage channel is communicated with the gas flow channel 101, the drainage performance of the bipolar plate is improved, and meanwhile, gas in the gas flow channel 101 can flow into different gas flow channels 101 through the inlet end of the drainage channel, so that the flow distribution of the gas in different gas flow channels 101 is realized, and the mass transfer effect of the bipolar plate is improved. According to the scheme, the drainage performance and the mass transfer performance of the bipolar plate can be improved only by adding the drainage channel 103, the structure is simple, and the production cost is low.
In this embodiment, the outlet end of the drain passage communicates with a gas common outlet that communicates with the gas flow passage. The outlet end of the water drainage channel 103 is communicated with the gas common outlet communicated with the gas flow channel 101, so that the structure is simple, a water drainage port is not additionally arranged on the bipolar plate, and liquid water is favorably drained under the pressure of reaction gas. Of course, for the bipolar plate on the cathode side, a drain port dedicated for draining water may be provided at the lower end of the bipolar plate, and then the outlet end of the drain channel is communicated with the drain port, and the water in the drain channel is drained out of the bipolar plate through the drain port.
It should be noted that, the structure of the drainage channel is not limited, and may be one drainage channel or multiple drainage channels, multiple drainage channels may be respectively communicated with the gas channel 101 and respectively discharged from the gas common outlet, or multiple drainage channels may be respectively communicated with the gas channel 101, and liquid water in the gas channel 101 is discharged, then collected together, and then discharged. In this embodiment, the latter is used to advantage in saving space on the bipolar plate. The specific structure is as follows:
the drain passage includes at least one branch flow groove 1031 and a confluence groove 1032 for collecting and discharging liquid water in the branch flow groove 1031 together into the same passage. The confluence groove 1032 is arranged at the lower end of the reaction region 10 of the bipolar plate and is spaced from the lowermost gas flow channel 101, and the confluence groove 1032 is communicated with the downstream gas distribution region 70; the flow dividing groove 1031 is communicated with the gas flow passage 101, and the flow dividing groove 1031 is also communicated with the flow converging groove 1032. Wherein, set up the little arch that a plurality of intervals set up in the gas distribution district, these little archs are used for the vortex, and then make gas can distribute in each gas flow channel 101 uniformly, perhaps, can discharge in following bipolar plate fast through the vortex effect, are favorable to discharging of liquid water simultaneously. The liquid water in the gas flow channels 101 flows into the manifold groove 1032 through the diversion grooves 1031, then flows from the manifold groove 1032 to the downstream gas distribution region 70, and exits the bipolar plate under the pressure of the gas. And the flow converging groove 1032 is arranged below the lowermost gas flow channel 101, so that liquid water is finally drained through the flow converging groove 1032, the gas flow channel 101 below is prevented from passively playing a role of the flow converging groove 1032, and the liquid water is blocked, and a part of reaction area is further lost. The diversion grooves 1031 can not only discharge liquid water in the gas flow channels 101 in time, but also establish a communication relationship between the gas flow channels 101, so that even if a certain section of the gas flow channel 101 is blocked, gas can flow into other unblocked gas flow channels 101 through the diversion grooves 1031, and further the influence of the blockage of the gas flow channel 101 is reduced.
Of course, the structural form of the diversion grooves 1031 and the confluence grooves 1032 are not limited, the diversion grooves 1031 and the confluence grooves 1032 may be linear or curved, and the groove depths of the diversion grooves 1031 and the confluence grooves 1032 may be the same or different. The groove depths of the diversion grooves 1031 and the converging grooves 1032 may be flush with the bottom of the gas flow channel 101, may also be deeper than the bottom of the gas flow channel 101, and of course may also be shallower than the bottom of the gas flow channel 101, as a preferred technical solution, the ratio of the groove depth of the converging grooves 1032 to the groove depth of the gas flow channel 101 is between 1/2-1. The width of the diversion groove 1031 is not limited as long as the liquid water in the gas flow passage 101 can be discharged. In order to further facilitate the discharge of the liquid water, the width of the drain passage is set to be not smaller than the width of the gas flow passage in the present embodiment. As a more preferable mode, the ratio between the groove width of the dividing groove 1031 and the width of the gas flow passage 101 is between 1 and 2, and likewise, the ratio between the groove width of the merging groove 1032 and the width of the gas flow passage 101 is between 1 and 2.
In the present embodiment, the bottom of the flow dividing grooves 1031 and the flow merging grooves 1032 are flush with the bottom of the gas flow passage 101. The bottom of the diversion grooves 1031 and the bottom of the confluence grooves 1032 are arranged to be flush with the bottom of the gas flow channel 101, which is beneficial to discharging liquid water in the gas flow channel 101, so as to further improve the water discharging performance of the bipolar plate.
Specifically, the gas flow passages 101 are straight flow passages, the plurality of gas flow passages are arranged at intervals, a ridge 102 rising upward from the bottom of the gas flow passage 101 is formed between two adjacent gas flow passages 101, a first groove 1031a is formed on the ridge 102 between two adjacent gas flow passages 101, the first groove 1031a is communicated with the two adjacent gas flow passages 101, and a diversion groove 1031 is formed after the first groove 1031a is communicated with the gas flow passages 101. Preferably, the plurality of dc channels are parallel to each other, and each of the ridges 102 has the same width. Of course, in other embodiments, the DC channels may not be parallel to each other, and the width of the ridges 102 may also be different. The first grooves 1031a are provided on the ridge 102, and the two adjacent gas flow passages 101 are communicated through the first grooves 1031a, so that the liquid water in the gas flow passage 101 located above can flow down along the first grooves 1031a into the next gas flow passage 101, then flow into the next gas flow passage 101 from the first grooves 1031a on the next ridge 102 until flowing into the flow-merging groove 1032, flow into the gas distribution region from the flow-merging groove 1032, and finally flow into the gas outlet common flow passage from the downstream gas distribution region 70 and flow out of the fuel cell stack. The first recess 1031a not only plays a role of discharging liquid water in the gas flow passages 101, but also enables gas to be distributed from the gas flow passages 101 to different gas flow passages 101 by the first recess 1031a communicating two adjacent gas flow passages 101.
Further, the angle between the first recess 1031a and the extension direction of the ridge is in the range of 45 ° -135 °. Setting the angle between the first recesses 1031a and the extending direction of the ridge within the range of 45 ° to 135 ° can achieve the discharge of liquid water into the confluence groove 1032 along the first recesses 1031 a. The included angles between the ridges 102 at different positions and the extending directions of the first grooves 1031a and the ridges at different positions of the same ridge 102 are not limited, and may be the same or different, as long as the communication between the adjacent gas flow passages 101 is realized.
Further, each of the ridges is provided with a plurality of first grooves spaced apart from each other. The plurality of first grooves are arranged on one ridge back, so that the drainage performance and the mass transfer performance of the bipolar plate can be further improved. The first grooves 1031a are distributed in an array on the bipolar plate. The first grooves 1031a are distributed on the bipolar plate in an array manner, so that the water drainage balance and the mass transfer uniformity of the bipolar plate are improved, and the bipolar plate has the advantage of convenience in processing.
In the present embodiment, the first recess 1031a is perpendicular to the extending direction of the ridge. On the one hand, the liquid water flows out along the first groove 1031a under the action of gravity, and on the other hand, the liquid water processing device is simple in structure and convenient to process. And, the first recesses 1031a located on the same column are on the same straight line. The first recesses 1031a in the same row are arranged on the same straight line, and when the liquid water in the gas flow passage 101 is discharged from the first recesses 1031a by gravity, the liquid water directly flows from the upper first recesses 1031a to the lower first recesses 1031a through the gas flow passage 101, and flows into the collecting tank 1032 along the first recesses 1031a in sequence and is discharged out of the stack. Therefore, the adoption of the structural form is beneficial to further improving the drainage performance of the bipolar plate.
In order to further improve the drainage performance and mass transfer performance of the bipolar plate, in the present embodiment, a plurality of protrusions 80 are provided at intervals on the gas flow channel 101 at positions avoiding the drainage channel 103, the protrusions 80 protrude from the bottom of the gas flow channel 101 toward the membrane plate, and the top surface of the protrusion 80 is lower than the top surface of the ridge 102 formed by the two gas flow channels 101. The convex parts 80 are arranged in the gas flow channel 101 at intervals, so that when gas is transferred to the positions of the convex parts 80 from the common section of the gas flow channel 101, the flowing direction of reaction gas deflects to generate a velocity component perpendicular to the gas diffusion layer, which is beneficial to the diffusion of the reaction gas to the gas diffusion layer, and meanwhile, due to the arrangement of the convex parts 80, the cross section of the gas flow channel 101 is reduced, the flow velocity is improved, and the liquid water in the diffusion layer is also beneficial to being taken away. In the present embodiment, the length of the convex portion 80 in the gas flow direction is between 1mm and 5mm, and the distance between two adjacent convex portions 80 is between 5mm and 20 mm.
A plurality of coolant inlets 110 are provided at the upper end of the bipolar plate at intervals along the length of the bipolar plate, and a plurality of coolant outlets 90 are provided at the lower end of the bipolar plate at intervals along the length of the bipolar plate. On the other hand, a coolant bridge 130 is provided on one side of the cooling surface of the bipolar plate, and the coolant bridge 130 is a groove recessed toward the reaction surface of the bipolar plate. The gas flow channel 101 has a third groove formed at a position corresponding to the raised portion 80, and both ends of the coolant bridge 130 are respectively connected to the third groove and the coolant inlet 110 of the bipolar plate. The third grooves formed by the bosses 80 on the reaction surface communicate with the coolant inlet 110 through the coolant bridge holes to form flow channels for the coolant, thereby simplifying the design of the cooling flow path.
Example 2
As shown in fig. 4 to 5, this embodiment is substantially the same as the embodiment 1, except that:
the gas flow channels 101 are wave-shaped flow channels, and a plurality of wave-shaped flow channels are arranged at intervals on the bipolar plate and extend in the horizontal direction. With the gas flow passage 101 having a wave shape, the gas flow passage 101 has peaks and valleys along the direction in which the gas flows, and the first recesses 1031a are provided at the positions of the valleys. Because the trough is in the lowest point of gas runner 101, liquid water easily collects in the trough department, consequently with first recess 1031a setting in the position of trough, can discharge along first recess 1031a after the liquid water in gas runner 101 flows to the trough along gas runner 101 from the crest of gas runner 101 under the effect of gravity in gas runner 101 to improve the drainage ability of gas runner 101, and then prevent that gas runner 101 from taking place at the phenomenon that the trough department is blockked up, still have the characteristics that improve the homogeneity of the mass transfer of bipolar plate simultaneously. Of course, in other embodiments, the first recess 1031a may also be disposed at other positions besides the peak, and the first recess 1031a may also be perpendicular to the flow path direction of the whole gas, or may have a certain angle, and may be disposed according to actual conditions.
Example 3
As shown in fig. 6 to 7, this embodiment is substantially the same as the embodiment 2, except that:
the gas flow path 101 is a serpentine flow path, and the diverting groove 1031 is communicated with a transverse portion of a lower end of the gas flow path 101. With the serpentine flow passage, the lateral portion at the lower end is at the lowest point of the gas flow passage where liquid water is likely to collect, thus communicating the diversion grooves 1031 to the gas flow passage 101 where the liquid water can flow from the diversion grooves into the collection grooves 1032 and out of the stack as it flows down the vertical portion of the gas flow passage 101 to the location of the lateral portion at the lower end. It is advantageous to prevent the gas flow channel 101 from being blocked at the lateral portion at the lower end by liquid water.
Further, a second groove 140 is formed on the ridge 102 between the vertical portions of the gas channels 101, and two ends of the second groove 140 respectively penetrate through the vertical portions of the gas channels 101 on two sides of the ridge 102. A second groove 140 is formed on the ridge 102 between the vertical portions of the gas flow channel 101 so that the second groove 140 communicates the adjacent two vertical portions, so that gas can flow from one vertical portion to the other vertical portion of the gas flow channel 101 through the second groove 140. Even if the bottom of the gas flow channel 101 is blocked, mass transfer in other parts of the gas flow channel 101 is not affected. Thus, the use of this structural form has the advantage of improving the mass transfer properties of the bipolar plate.
In this embodiment, one serpentine channel may be disposed on the bipolar plate, or a plurality of serpentine channels may be disposed in parallel and spaced apart from each other. With the latter, the splitter box communicates the transverse portion of the bottom of each serpentine channel.
Example 4
This example provides a single cell in which a bipolar plate has the structure as in any one of examples 1 to 3. The bipolar plate used in the single cell can improve the drainage performance of the single cell, improve the mass transfer performance of the single cell and further improve the performance of the single cell.
Here, the operation of the hydrogen fuel cell system using the single cell in the present embodiment will be briefly described, taking the hydrogen fuel cell system as an example: hydrogen enters a fuel gas inlet common channel in the fuel cell stack from a hydrogen inlet, enters the bipolar plate on the anode side from a fuel gas inlet 20, and is distributed into a gas channel 101 through an upstream gas distribution region 60; the same air enters the common oxidant inlet flow channel in the fuel cell stack from the oxidant inlet and enters the bipolar plates on the cathode side from the oxidant gas inlet 30, flows into the gas flow channels through the upstream gas distribution section 60, the hydrogen and air diffuse toward the membrane electrodes, and after electrochemical reaction on the membrane electrodes, the remaining hydrogen and air flow out of the gas flow channels on the anode and cathode sides, respectively. Most of the water generated during the electrochemical reaction is discharged from the fuel gas outlet common flow passage and the oxidant outlet common flow passage under the force of the surplus gas. And a part of the liquid water is collected in the gas flow passage, and as the part of the liquid water increases, the liquid water flows into the confluence groove through the first recess 1031a during the flow in the gas flow passage 101, and finally is discharged out of the stack through the gas common outlet, or is discharged out of the stack through a special water discharge outlet.
Although specific embodiments of the present invention have been described above, it will be understood by those skilled in the art that this is by way of example only and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and the principles of the present invention, and these changes and modifications are all within the scope of the present invention.
Claims (10)
1. A bipolar plate for a fuel cell, the bipolar plate having at least one gas flow channel for conveying a reactant gas, the bipolar plate further having a water drainage channel, the water drainage channel having an inlet end and an outlet end along a water flow direction, the inlet end communicating with each of the gas flow channels, the outlet end of the water drainage channel extending below the gas flow channels and communicating with the outside of the bipolar plate.
2. The bipolar plate of claim 1, wherein the drainage channel comprises:
the confluence groove is arranged at the lower end of the reaction area of the bipolar plate and is spaced from the gas flow channel at the lowest part, the confluence groove extends along the flowing direction of the reaction gas, and the outlet end is positioned on the confluence groove;
the splitter box is communicated with the gas flow channel and the confluence groove.
3. The bipolar plate of claim 2, wherein the gas flow channels are straight flow channels or wavy flow channels, the plurality of gas flow channels are arranged at intervals, a ridge is formed between two adjacent gas flow channels, each ridge is provided with a first groove, the first groove is communicated with two adjacent gas flow channels, and a flow path formed by the first groove and the gas flow channels after being communicated is the diversion channel.
4. The bipolar plate of claim 3 wherein each of said lands has a plurality of said first grooves spaced apart from one another; the first grooves are distributed on the bipolar plate in an array.
5. The bipolar plate of claim 3 wherein the angle between said first groove and the direction of extension of said ridge ranges between 45 ° and 135 °.
6. The bipolar plate of claim 3, wherein the gas flow channels have peaks and valleys in a direction of gas flow when the gas flow channels are wave-shaped channels, and the first grooves are provided at positions of the valleys.
7. The bipolar plate of claim 2, wherein the gas flow channels are serpentine flow channels, and the divided flow channel communicates with a lateral portion of a lower end of the gas flow channels;
and a second groove is formed in the ridge between the vertical parts of the gas flow channels, and two ends of the second groove are respectively communicated with the vertical parts of the gas flow channels on two sides of the ridge.
8. The bipolar plate of any one of claims 1 to 7, wherein said outlet end communicates with a common gas outlet port communicating with said gas flow channels; the bottom of the drainage channel is flush with the bottom of the gas flow channel; the width of the drainage channel is not less than the width of the gas flow channel.
9. The bipolar plate as claimed in any one of claims 1 to 7, wherein a plurality of protrusions are provided at intervals in the gas flow channel at positions avoiding the water drain channel, the protrusions protruding from the bottom of the gas flow channel toward the membrane plate, and the top surfaces of the protrusions are lower than the top surfaces of the ridges on both sides of the gas flow channel;
and a coolant bridge is arranged on the side surface of the bipolar plate, which is far away from the gas flow channel, a third groove is formed at the position corresponding to the bulge, and two ends of the coolant bridge are respectively communicated with the third groove and a coolant inlet on the bipolar plate.
10. A cell comprising a bipolar plate according to any one of claims 1 to 9.
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| CN113097525A (en) * | 2021-05-10 | 2021-07-09 | 上海电气集团股份有限公司 | Bipolar plate and single cell comprising same |
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| CN113097525A (en) * | 2021-05-10 | 2021-07-09 | 上海电气集团股份有限公司 | Bipolar plate and single cell comprising same |
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