fuel cell

Abstract

Fuel cell, comprising: a reaction layer (100) comprising a membrane electrode assembly MEA (120) and gas diffusion layers GDL (140) each disposed on both side surfaces of the MEA (120); a porous separation layer (200) having a surface adhered to a surface of the reaction layer (100) and to which a reaction gas is supplied; and a cathode bipolar plate (300) having a panel shape and held on another surface of the porous separating layer (200), wherein a front end portion of the cathode bipolar plate (300) has a distributor (320) to which the reaction gas is supplied, and a plurality of diffusion channels (340) via which the reaction gas leads from the distributor (320) towards the porous separation layer (200), wherein some of the diffusion channels (340) extend to a rear end portion of the cathode bipolar plate (300), and wherein the cathode bipolar plate (300) has a partition wall channel (342) separating the porous separation layer (200), extending in a direction in which the reaction gas flows, and extending from the distributor (320) in an oblique direction.

Description

[0001] The invention relates generally to a fuel cell, and more particularly to a fuel cell capable of distributing a uniform flow of reaction gas and cooling water throughout the reaction area and smoothly discharging condensate generated by a chemical reaction in the fuel cell.

[0002] A fuel cell typically comprises a membrane electrode assembly (MEA) with a catalyst layer that generates a chemical reaction between hydrogen and oxygen. Bipolar plates are arranged on both sides of the MEA and facilitate the removal of water while supplying hydrogen and oxygen to the MEA.

[0003] The MEA and the bipolar plates, which are arranged on both sides of the MEA and supply either hydrogen or oxygen, form the fuel cell. The fuel cell is stacked multiple times to form a fuel cell stack.

[0004] To maximize fuel cell performance, a porous element of the bipolar plate evenly distributes surface pressure and improves the performance of diffusing reaction gas and dissipating generated water. The porous element includes elements having a microporous structure of conductive porous bodies, such as a three-dimensional structure made of a metal or carbon material with micropores, a three-dimensional structure with a porous structure formed by weaving a metal wire into a mesh, a three-dimensional structure formed by forming holes in a thin metal plate or by creating grooves in the thin metal plate, and so on. All of these elements evenly distribute surface pressure.

[0005] However, according to the current technology, the flow of reaction gas and generated water cannot be controlled due to the use of the porous element, and the reaction surface cannot be utilized efficiently. Furthermore, if moisture is maintained in a supersaturated state in the fuel cell, the micropores of the porous element become clogged, reducing the stability and efficiency of the fuel cell.

[0006] DE 10 2015 205 227 A1 describes a fuel cell comprising a conductive microscopic body formed on a reaction surface of a separator corresponding to a membrane electrode assembly and configured to supply a reaction gas to the membrane electrode assembly, wherein partition walls dividing the microporous body into a plurality of sections are formed on the reaction surface of the separator.

[0007] The invention provides a fuel cell capable of distributing a uniform flow of reaction gas and cooling water over the entire reaction area and gently discharging condensate generated by a chemical reaction in the fuel cell.

[0008] According to the invention, a fuel cell comprises a reaction layer including a membrane electrode assembly (MEA) and gas diffusion layers (GDL) respectively disposed on both side surfaces of the MEA, a porous separator layer having a surface adhered to one surface of the reaction layer and to which a reaction gas is supplied, and a cathode bipolar plate having a panel shape and adhered to another surface of the porous separator layer, having a front end portion provided with a manifold to which the reaction gas is supplied, and a plurality of diffusion channels through which the reaction gas flows from the manifold toward the porous separator layer. Some of the diffusion channels extend to a rear end portion of the cathode bipolar plate.The cathode bipolar plate has a partition channel which separates the porous separation layer, extends in a direction in which the reaction gas flows, and extends in an oblique direction.

[0009] The partition wall channel of the cathode bipolar plate may extend in the oblique direction, which is a gravitational direction, so as to lead from an upper side to a lower side in a state in which the partition wall channel is used in the fuel cell.

[0010] The fuel cell may further comprise an anode bipolar plate configured to be held to a surface of the cathode bipolar plate and bent a plurality of times in one lateral direction and the opposite lateral direction to form a gas channel through which the reaction gas passes through a first open space of one side of the anode bipolar plate and a cooling channel through which a coolant passes through a second open space of another side of the anode bipolar plate.

[0011] The cooling channel and the gas channel of the anode bipolar plate may have front end sections which are connected to the distributor in such a way that the coolant and the reaction gas can be supplied to them.

[0012] The partition wall channel of the cathode bipolar plate may have a recessed portion recessed in a direction from one side to the other side of the anode bipolar plate to form a third open space, the second open space overlapping with the third open space to share the cooling medium of the cooling channel with the partition wall channel.

[0013] The cooling channel and the gas channel of the anode bipolar plate may extend from the manifold in a straight direction, and the partition wall channel of the cathode bipolar plate may extend from the manifold in the oblique direction, such that a partition wall channel overlaps with a plurality of different cooling channels.

[0014] The partition wall channel of the cathode bipolar plate may extend in a straight direction toward the direction in which the reaction gas flows and then extend in the oblique direction.

[0015] The reaction layer and the porous separation layer may extend in the straight direction toward the direction in which the reaction gas flows and then extend in the oblique direction.

[0016] The distributor may include an inlet-side distributor provided at the front end portion of the cathode bipolar plate and an outlet-side distributor provided at the rear end portion of the cathode bipolar plate.

[0017] As can be seen from the above description, the fuel cell has the advantage that the flow of reaction gas and cooling water can be evenly distributed over the entire reaction area, and the condensate generated by the chemical reaction in the fuel cell can be smoothly discharged, thereby preventing the flow of reaction gas from being blocked due to the condensate.

[0018] The invention is explained in more detail with reference to the drawing. The drawing shows: Fig. 1 is a plan view of the configuration of a fuel cell according to a first exemplary embodiment of the invention; Fig. 2 and Fig. 3 sectional views of the fuel cell configuration from Fig. 1; Fig. 4 a view describing the fuel cell from Fig. 1; and Fig. 5 a view of a fuel cell according to a second exemplary embodiment of the invention.

[0019] The following is based on the Fig. 1 to 5 describe a fuel cell according to exemplary embodiments of the invention.

[0020] A fuel cell according to exemplary embodiments of the invention is supplied with reaction gas formed from oxygen gas and hydrogen gas and utilizes a chemical reaction of hydrogen and oxygen to generate electrical energy.

[0021] Here, heat is generated as a reaction by-product, and generated water is discharged as condensate.

[0022] According to exemplary embodiments of the invention, cooling efficiency is increased by discharging generated water in a fuel cell and by smoothly moving the flow of a coolant that cools heat.

[0023] As in the Fig. 1 and Fig. As shown in Figure 2, a fuel cell according to a first exemplary embodiment of the invention includes a reaction layer 100 having a membrane electrode assembly (MEA) 120 and gas diffusion layers (GDL) 140 disposed on both side surfaces of the MEA 120. A porous separation layer 200 has a surface adhered to one surface of the reaction layer 100 and is supplied with reaction gas. A cathode bipolar plate 300 has a panel shape and is adhered to another surface of the porous separation layer 200. The cathode bipolar plate 300 has a front end portion with a manifold 320 to which reaction gas is supplied and a plurality of diffusion channels 340 through which the reaction gas flows from the manifold 320 toward the porous separation layer 200. Some of the diffusion channels 340 extend to a rear end portion of the cathode bipolar plate 300.The cathode bipolar plate 300 further includes a partition wall channel 342 that separates the porous separation layer 200. The partition wall channel 342 extends in a direction in which the reaction gas flows and then extends in an oblique direction.

[0024] The MEA 120 and the GDL 140 of the reaction layer 100 generate electrical energy through an electrochemical reaction in the reaction gas comprising hydrogen gas and oxygen gas. Furthermore, the porous separation layer 200 is adhered to a surface of the reaction layer 100 supplied with the reaction gas and guides the reaction gas to the reaction layer 100 depending on the flow. Here, the porous separation layer 200 may be made of a metal or carbon material formed in a wire mesh structure, or a material provided with a plurality of micro-openings formed by forming holes in a thin metal plate or scoring the thin metal plate.

[0025] The above-mentioned reaction layer 100 and the porous separation layer 200 are known in the technical field of fuel cells, so their detailed description is omitted.

[0026] According to the invention, in order to efficiently flow the reaction gas and discharge the generated water, the cathode bipolar plate 300 has a panel shape and adheres to one surface of the porous separation layer 200. The front end portion of the cathode bipolar plate 300 includes the manifold 320 to which the reaction gas is supplied and the plurality of diffusion channels 340 through which the reaction gas flows from the manifold 320 toward the porous separation layer 200. Some of the diffusion channels 340 extend to the rear end portion of the cathode bipolar plate 300. The cathode bipolar plate 300 further includes the partition wall channel 342 that separates the porous separation layer 200. The partition wall channel 342 extends in a direction in which the reaction gas flows and extends in an oblique direction.

[0027] The front end portion of the cathode bipolar plate 300 includes the manifold 320, which includes an inlet-side manifold 322 provided at the front end portion of the cathode bipolar plate 300 and an outlet-side manifold 324 provided at the rear end portion of the cathode bipolar plate 300. That is, the reaction gas is supplied from the inlet-side manifold 322 to generate the electric power, and the discharged generated water or the like is discharged via the outlet-side manifold 324.

[0028] In particular, the cathode bipolar plate 300 has the plurality of diffusion channels 340 such that they lead from the manifold 320 toward the porous separation layer 200 to supply the reaction gas supplied from the manifold 320 to the porous separation layer 200, wherein some of the diffusion channels 340 extend to the rear end portion and traverse the porous separation layer 200 to form the partition wall channel 342 separating the porous separation layer 200.

[0029] The partition wall channel 342 may extend in an oblique direction, which is a gravitational direction, such that it leads from an upper side to a lower side in a state where the partition wall channel 342 is used in the fuel cell. According to the invention, in order to collect the water generated by the electrochemical reaction between the porous separation layer 200 and the reaction layer 100, as shown in Fig. As shown in FIG. 1, in a state where the fuel cell stack is arranged in a direction perpendicular to the direction of gravity, the water generated by the porous separator layer 200 can be smoothly discharged while flowing downward from the top to the bottom in the direction of gravity. Therefore, under the condition that excessively generated water is generated, the generated water is discharged to the outlet-side manifold 324 so that it cannot accumulate in the fuel cell, thereby ensuring and maintaining the efficiency of the fuel cell.

[0030] With reference to Fig. 2, the fuel cell may further comprise an anode bipolar plate 400 which is fixed to a surface of the cathode bipolar plate 300 and bent a plurality of times in one direction and the opposite direction so as to form a gas channel 420 through which the reaction gas passes through an open space 422 on one side thereof, and a cooling channel 440 through which a coolant passes through an open space 442 on the opposite side thereof.

[0031] The cooling channel 440 and the gas channel 420 of the anode bipolar plate 400 have front end portions that are connected to the distributor 320 such that the coolant and the reaction gas can be supplied to them, respectively.

[0032] That is, the anode bipolar plate 400 adheres to one surface of the cathode bipolar plate 300 and is bent several times in one direction and the opposite direction to form the gas channel 420 and the cooling channel 440. Here, the reaction gas supplied from the manifold 320 passes through the gas channel 420 formed on one side of the anode bipolar plate 400, and the coolant passes through the cooling channel 440 formed on the other side thereof. Thus, the reaction gas is supplied to the reaction layer 100 adhered to one side of the anode bipolar plate 400, and a space is formed for moving the coolant through the cathode bipolar plate 300 adhered to another side of the anode bipolar plate 400, thereby smoothly moving the coolant.

[0033] In particular, as in Fig. 3, since the partition wall channel 342 of the cathode bipolar plate 300 protrudes to the opposite side to form an open space 344 on one side, and the cooling channel 440 of the anode bipolar plate 400 has the open space 442 on the other side, a portion overlapping with the cooling channel 440 may be formed at an extension line of the partition wall channel 342 to share the coolant of the cooling channel 440 with the partition wall channel 342.

[0034] As a result, the space 344 of the partition channel 342 of the cathode bipolar plate 300 is open on one side, and the open space 442 of the cooling channel 440 of the anode bipolar plate 400 is formed on the other side. Specifically, the partition channel 342 extends in the oblique direction to form the portion where the partition channel 342 overlaps with the cooling channel 440 at the extension line of the partition channel 342, so as to share the coolant of the cooling channel 440 with the partition channel 342, thereby improving cooling efficiency.

[0035] That is, the cooling channel 440 and the gas channel 420 of the anode bipolar plate 400 extend from the manifold 320 in a straight direction, and the partition wall channel 342 of the cathode bipolar plate 300 extends from the manifold 320 in an oblique direction, so that a partition wall channel 342 overlaps with a plurality of different cooling channels 440. As shown in Fig. 3, the partition wall passage 342 may extend in the oblique direction so as not to share the open space 344 with any cooling passage 440 and to share the open space 344 with other cooling passages 440, thereby preventing the coolant flowing in the cooling passage 440 from excessively circulating to the partition wall passage 342 side.

[0036] Since the cooling channel 440 of the anode bipolar plate 400 extends in the straight direction, the heat generated by the electrochemical reaction in the gas channel 420, the porous separation layer 200 and the reaction layer 100 can be cooled. In particular, as shown in Fig. As shown in Figure 4, since the partition wall channel 342 extends in the oblique direction, the portion where the partition wall channel 342 overlaps with the plurality of cooling channels 440, and therefore, the coolant of the cooling channel 440 moves through the partition wall channel 342 in such a way that a pressure difference due to the flow of the coolant is reduced, thereby increasing the cooling efficiency. The coolant moving through the cooling channel 440 of the anode bipolar plate 400 can also be distributed into the partition wall channel 342 to prevent the cooling water from penetrating the space where the electrochemical reaction is carried out due to the excessive pressure difference.

[0037] As described above, the fuel cell has a structure in which the reaction layer 100, the anode bipolar plate 400, the cathode bipolar plate 300, and the reaction layer 100 are stacked sequentially from one side to the other, and in which the reaction gas supplied from the manifold 320 moves through the porous separation layer 200, the reaction layer 100, and the gas channel 420 of the anode bipolar plate 400 to generate electrical energy through electrochemical reaction. The coolant supplied from the manifold 320 is distributed and moved into the cooling channel 440 of the anode bipolar plate 400 and the partition wall channel 342 of the cathode bipolar plate 300 to perform efficient cooling and prevent the pressure difference of the cooling water from being reduced.

[0038] With reference to Fig.5, in a fuel cell according to a second exemplary embodiment of the invention, the partition wall channel 342 of the cathode bipolar plate 300 may extend a predetermined distance in a straight direction to a direction in which the reaction gas flows, and then may extend in the oblique direction.

[0039] That is, the reaction gas supplied via the inlet-side manifold 322 is evenly distributed in the diffusion channel 340 of the cathode bipolar plate 300. Due to the reaction gas supplied via the manifold 320, the generated water does not stagnate in the inlet-side manifold 322, and the generated water is collected from a specific point extending a predetermined distance. Since the partition wall channel 342 of the cathode bipolar plate 300 extends in the straight direction with respect to the portion where the generated water does not stagnate, the reaction gas is evenly distributed from the manifold 320, and the partition wall channel 342 extends in the oblique direction from the point where the reaction gas stagnates, allowing the generated water to flow smoothly in the gravitational direction, thereby discharging the generated water.

[0040] Here, the point where the generated water is generated and stagnates depending on the flow of the reaction gas can be derived from an experiment and set differently according to the specifications of the fuel cell.

[0041] In addition, like the partition wall channel 342, the reaction layer 100 and the porous separation layer 200 may extend a predetermined distance in the straight direction to the direction in which the reaction gas flows, and then may extend in the oblique direction.

[0042] The reaction layer 100 and the porous separation layer 200 equally extend in the oblique direction at the point where the partition wall channel 342 extends in the oblique direction, and therefore the reaction gas uniformly distributed in the inlet-side manifold 322 is uniformly distributed and moved up to the outlet-side manifold 324.

[0043] Thereby, due to the uniform distribution of the reaction gas, the uniformity of the pressure difference and the utilization of the reaction area can be ensured, and the generated water generated in the specific point can easily flow over the cathode bipolar plate 300 to be discharged.

[0044] According to the invention, the flow of reaction gas and cooling water can be evenly distributed over the entire reaction area, and the discharge of the condensate generated by the chemical reaction in the fuel cell can be smoothly carried out, thereby preventing the flow of reaction gas from being blocked due to the condensate.

Claims

[1] Fuel cell, comprising: a reaction layer (100) comprising a membrane electrode assembly MEA (120) and gas diffusion layers GDL (140) each disposed on both side surfaces of the MEA (120); a porous separation layer (200) having a surface adhered to a surface of the reaction layer (100) and to which a reaction gas is supplied; and a cathode bipolar plate (300) having a panel shape and held on another surface of the porous separating layer (200), wherein a front end portion of the cathode bipolar plate (300) has a distributor (320) to which the reaction gas is supplied, and a plurality of diffusion channels (340) via which the reaction gas leads from the distributor (320) towards the porous separation layer (200), wherein some of the diffusion channels (340) extend to a rear end portion of the cathode bipolar plate (300), and wherein the cathode bipolar plate (300) has a partition wall channel (342) separating the porous separation layer (200), extending in a direction in which the reaction gas flows, and extending from the distributor (320) in an oblique direction. [2] The fuel cell according to claim 1, wherein the partition wall channel (342) of the cathode bipolar plate (300) extends in the oblique direction, which is a gravitational direction, so as to lead from an upper side to a lower side in a state in which the partition wall channel (342) is used in the fuel cell. [3] Fuel cell according to claim 1 or 2, further comprising: an anode bipolar plate (400) which is fixed to a surface of the cathode bipolar plate (300) and is bent several times in one direction and the opposite direction so as to form a gas channel (420) via which the reaction gas passes through a first open space (422) formed on one side of the anode bipolar plate (400), and a cooling channel (440) via which a coolant passes through a second open space (442) formed on another side of the anode bipolar plate (400). [4] The fuel cell according to claim 3, wherein the cooling channel (440) and the gas channel (420) of the anode bipolar plate (400) have front end portions each connected to the manifold (320). [5] The fuel cell according to claim 3 or 4, wherein the partition wall channel (342) of the cathode bipolar plate (300) has a recessed portion recessed in a direction from one side to the other side of the anode bipolar plate (400) to form a third open space (344), the second open space (442) overlapping with the third open space (344) to share the coolant of the cooling channel (440) with the partition wall channel (342). [6] The fuel cell according to claim 5, wherein the cooling channel (440) and the gas channel (420) of the anode bipolar plate (400) extend from the manifold (320) in a straight direction, and the partition wall channel (342) of the cathode bipolar plate (300) extends from the manifold (320) in the oblique direction, so that one partition wall channel (342) overlaps with a plurality of different cooling channels (440). [7] The fuel cell according to any one of claims 1 to 6, wherein the partition wall channel (342) of the cathode bipolar plate (400) extends in a straight direction toward the direction in which the reaction gas flows and then extends in the oblique direction. [8] The fuel cell according to any one of claims 1 to 7, wherein the reaction layer (100) and the porous separation layer (200) extend in the straight direction toward the direction in which the reaction gas flows and then extend in the oblique direction. [9] The fuel cell according to any one of claims 1 to 8, wherein the manifold (320) comprises an inlet-side manifold (322) provided at the front end portion of the cathode bipolar plate (300) and an outlet-side manifold (324) provided at the rear end portion of the cathode bipolar plate (300).

Images