TWM450081U - Fuel cell stack and separator thereof - Google Patents

Description

Fuel cell stack and its separator

The present invention relates to a fuel cell stack and a partition plate thereof, and particularly to a separator plate of the same structure for use in a positive electrode and a cathode of a fuel cell, respectively, to reduce the manufacturing cost of the fuel cell, and the gas flow path The formed cluster-shaped block enables the fuel gas and the oxidant to be evenly distributed on the gas flow path surface to improve the power generation efficiency of the fuel cell.

According to the traditional petrochemical energy has been exhausted, and the use of petrochemical energy will have a great impact on the ecological environment, the development of low-pollution and high-efficiency energy use has become an important issue; In the development of new energy utilization methods (such as solar cells, biochemical energy, or fuel cells, etc.), the high power generation efficiency (about 60%) and low pollution of fuel cells make them attract attention; fuel cells are a kind of utilizing chemical energy. A power generation device directly converted into electric energy, the fuel may be methanol, ethanol, hydrogen or other hydrocarbons, and then oxygen is used as an oxidant to generate electric energy, and water is generated as a by-product in such an electrochemical reaction; Compared with the conventional power generation method, the fuel cell has the advantages of low pollution, low noise, high energy conversion efficiency, and the fuel cell is directly generated by the oxidation of the fuel, so that the discharge current can increase as the fuel supply increases, and As long as fuel and oxygen are continuously supplied, electricity can be generated continuously, so there is no power failure. Charging problem, and become very forward-looking and clean energy.

Basically, a fuel cell is a power generation device that converts chemical energy into electrical energy by using a reverse reaction of water electrolysis; in the case of a proton exchange membrane fuel cell, it is mainly composed of a membrane electrode assembly (MEA) and The two separator plates are formed, and the membrane electrode group is the core of the fuel cell. As a function of the electrochemical reaction, the membrane electrode group can be divided into three-layer, five-layer or seven-layer structures according to the number of structural layers; The five-layer membrane electrode assembly consists of a proton exchange membrane, an anode catalyst layer, a cathode catalyst layer, an anode gas diffusion layer (GDL), and a cathode gas diffusion layer. Composition; wherein the proton exchange membrane is disposed in the middle, which is itself a high molecular polymer, as a function of conducting (hydrogen ions) and isolating the reaction gases on both sides, which can be regarded as a solid electrolyte, An anode catalyst layer and a cathode catalyst layer are respectively disposed on both sides of the sub-exchange membrane. The main function of the catalyst layer is to accelerate the reaction efficiency, and the anode gas diffusion layer and the cathode gas diffusion layer are respectively disposed on the anode catalyst layer and the cathode contact layer. Above the medium layer, the two partition plates comprise an anode and a cathode respectively disposed on the anode gas diffusion layer and the cathode gas diffusion layer, wherein the gas diffusion layer mainly functions to effectively uniformly disperse the anode end of the methanol (DMFC) or It is hydrogen (PEMFC), and the oxygen at the cathode end, while eliminating the water generated at the cathode end; usually, the material of the gas diffusion layer is mainly carbon paper or carbon cloth.

In general, the partition plate is one of the key factors affecting the commercialization of fuel cells. There are many problems to be solved in the material of the separator plate, the flow field structure and the processing cost. The conventional separator materials are mainly graphite and composite. Carbon materials and metal substrates, for graphite and composite carbon separators, have the advantages of electrical conductivity and corrosion resistance, but the process is complicated, labor-intensive, and the thickness of the separator made of the material is limited. About 3mm is not conducive to the miniaturization of the fuel cell; while for the metal substrate, although the thickness is small and the quality is light, the volume and quality of the fuel cell can be reduced, but since the fuel of the fuel cell is through the flow channel Transportation, so the transport capacity of the flow channel affects the power generation efficiency of the fuel cell; therefore, how to use the geometry or flow field characteristics of the flow channel on a small partition plate to design a fuel cell stack that is conducive to fuel diffusion The partition has become an important issue.

In view of this, the creators have improved the creation of a fuel cell stack and its separators with years of experience in the design, development and practical production of the relevant industries. The purpose is to provide a partition plate with the same structure. The use of the anode and cathode of the fuel cell avoids the need for two differently designed separator plates for conventional fuel cells to reduce the manufacturing cost of the fuel cell and the cluster-shaped blocks formed by the gas flow paths. Both the fuel gas and the oxidant can be evenly distributed on the gas flow path surface to improve the power generation efficiency of the fuel cell.

In order to achieve the above-mentioned object, the present inventors propose a fuel cell stack and a partition plate thereof, and a partition plate of a metal substrate (for example, stainless steel) has a gas flow surface formed by multiple press working and corresponding a coolant flow passage surface of the gas flow passage surface, the gas flow passage surface and the coolant flow passage surface have a plurality of grooves corresponding to opposite recesses and projections, and the groove of the gas flow passage surface is formed with a first gas flow passage, a second gas flow channel, and a plurality of third gas flow channels between the first gas flow channel and the second gas flow channel, the first to third gas flow channels each having a plurality of bends, and the first and second gas flows The two curved connecting lines are respectively a straight shape and a cluster shape, and the two bending connecting lines of the third gas flow path are all corresponding arrow cluster shapes, and the tips of the arrow shapes are located on the same horizontal line. Thereby, the partition plate utilizes the cluster-shaped block formed by the first to third gas flow passages of the crucible, so that the fuel gas can be uniformly distributed on the gas flow passage surface, ensuring that the reaction gas has a sufficient concentration to enter the membrane electrode assembly. To It can fully react with the thin film electrode group to improve the power generation efficiency of the fuel cell; in addition, when the two partition plates are joined by the coolant flow path surface, the space not contacted between the two partition plates forms a three-dimensional flow field of the coolant, that is, The groove of the coolant passage surface forms a linear flow path for conveying the coolant, thereby reducing the flow resistance of the coolant, avoiding the problem of clogging of the coolant in the fuel cell stack, effectively cooling the fuel cell, and thereby stabilizing the operating temperature of the battery. Demand, avoiding excessive temperature and affecting battery performance and even causing component damage; furthermore, since the partition plate of the present invention is made of a metal substrate, it has the advantages of small thickness and light weight, and can not only reduce the volume of the fuel cell. It can also meet the demand for light weight, and only need to design (open the mold) a separator plate that can be used for the anode and cathode of the fuel cell, so as to avoid the need for two different designs of the separator plate for the conventional fuel cell. Effectively reduce the manufacturing cost of fuel cells due to mold complexity.

Furthermore, a corresponding coolant inlet passage and a coolant outflow channel are respectively disposed at the center of the two side ends of the partition plate, and a first gas intake manifold and a second portion are respectively disposed on the two sides of the coolant entering the manifold. a gas intake manifold, and a first gas exhaust manifold and a second gas exhaust manifold are respectively disposed on two sides of the coolant outflow channel, wherein the first gas intake manifold and the first gas exhaust manifold The diagonal is set, and the second gas intake manifold and the second gas exhaust manifold are also diagonally disposed, and the first and second gas intake manifolds are combined with the first and second gas exhaust manifolds. The groove of the gas flow passage surface communicates, and the coolant enters the manifold and the coolant outflow channel communicates with the groove of the coolant flow passage surface; in addition, the gas flow passage surface may further be provided with a gastight structure, and the airtight structure The system is disposed around the first gas intake manifold and the first gas exhaust manifold so as not to communicate with the groove of the gas flow passage surface, or the airtight structure is disposed on the second gas intake manifold and the first The circumference of the two gas exhaust manifolds is not connected to the grooves of the gas flow passage surface; thereby, The gas inlet and outlet can be arranged diagonally to increase the uniform distribution of the gas on the gas flow path surface, and also prevent the fuel gas and the coolant from leaking into the environment, thereby causing the battery performance to be degraded and damaged, or even caused by leakage. safe question.

The fuel cell stack separator as described above, wherein the total lengths of the first to third gas flow paths are respectively the same.

The fuel cell stack separator as described above, wherein the total number of bends of the first to third gas flow paths are the same.

The fuel cell stack separator plate as described above, wherein the two partition plates are bonded by solder joint or conductive glue, and the solder joints are used for transferring electrons between the partition plates; further, the soldering method is preferably laser. Spot welding and two partition plates, because of the high energy density, low heat input and small heat impact, the laser welding (LBW) can effectively reduce the occurrence of weld hot cracking and welding sensitization.

The present invention further provides that the fuel cell stack separators are respectively disposed at the two side ends of the conventional membrane electrode assembly to form the fuel cell unit, and the plurality of fuel cell units are formed to form the fuel cell stack.

The purpose of this creation and its structural and functional advantages will be explained in accordance with the structure shown in the following figure, in conjunction with specific examples, so that the review committee can have a deeper and more specific understanding of the creation.

First, please refer to the first figure, which is a three-dimensional exploded view of the cell structure of the preferred embodiment. It is worth noting that the main function of the separator (1) of the fuel cell stack is to guide the reaction gas (oxidant). And the fuel and the coolant are respectively introduced into the flow channel by the first and second gas intake manifolds (17), (18) and the coolant entering the channel (15), and the reaction gas and the coolant are distributed by the design of the flow channel. In the reaction area, the unused reaction gas, product water and coolant are then discharged from the flow channel; for convenience of explanation, the unit cell structure is located on the left side of the membrane electrode group (2) (1) Defined as a first partition plate (1a), and the first partition plate (1a) serves as an anode for fuel (which may be, for example, hydrogen), and a partition plate (1) on the right side of the membrane electrode group (2) Defined as a second dividing plate (1b), and the second dividing plate (1b) acts as a cathode for the oxidant (for example, air); and its operation principle is that the fuel gas enters from the anode of the fuel cell, oxygen Or air) enters the fuel cell from the cathode, and through the action of the membrane electrode assembly (2), the hydrogen atoms of the anode are decomposed into two hydrogen protons and two electrons, wherein the hydrogen protons are attracted to the cathode by oxygen. The electrons form a current through an external circuit and reach the cathode, and hydrogen protons, oxygen, and electrons react at the cathode to form water molecules. The operation of the electrons is well-known in the art, and is not the focus of this creation. Therefore, the technical features of the present invention focus on the arrangement and arrangement of the flow path through the partition plate (1), so that the space between the partition plate (1) and the partition plate (1) can be formed into a straight line. Shaped cooling water flow path, and the flow path of the arrow cluster shape can also make the reaction gas more evenly distributed on the gas flow channel surface (11); please refer to the second and third figures together, respectively, which is a preferred embodiment of the present invention. The schematic diagram of the gas flow channel surface of the single cell separator plate and the coolant flow channel surface, the fuel cell stack separator plate (1) of the present invention has a plurality of stamping processes. The gas flow passage surface (11) and the coolant flow passage surface (12) corresponding to the gas flow passage surface (11), the gas flow passage surface (11) and the coolant flow passage surface (12) have corresponding opposite depressions and projections An alternating plurality of grooves (13), the groove (13) of the gas flow path surface (11) is formed with a first gas flow path (111), a second gas flow path (112), and a first gas flow a plurality of third gas flow passages (113) between the passage (111) and the second gas flow passage (112), and the first, second, and third gas flow passages (111), (112), and (113) each have a plurality of bends Folding (114), and the first and second gas flow passages (111), (112) and the two bending (114) connecting lines are respectively a linear shape and an arrow cluster shape, and the third gas flow passage (113) The bending (114) connecting lines are all in the shape of the corresponding arrow clusters, and the tip ends (14) of the arrow cluster shapes are located on the same horizontal line; wherein, the two partition plates (1) are in the coolant flow channel surface (12) When joining, the space that is not in contact between the two partition plates (1) forms a three-dimensional flow field of the coolant, that is, the groove (13) of the two coolant flow passage faces (12) forms a straight flow path for conveying the coolant (121) ).

Furthermore, a corresponding coolant inlet passage (15) and a coolant outflow passage (16) are respectively disposed at the center of the two side ends of the partition plate (1). In the present embodiment, the coolant may be water; The first gas inlet manifold (17) and the second gas inlet manifold (18) are respectively disposed on the two sides of the coolant inlet manifold (15), and are respectively disposed on two sides of the coolant outflow channel (16). a first gas exhaust manifold (19) and a second gas exhaust manifold (20), wherein the first gas of the embodiment may be, for example, a hydrogen fuel, and the second gas may be, for example, oxygen (air), and The first gas intake manifold (17) and the first gas exhaust manifold (19) are diagonally disposed, and the second gas intake manifold (18) and the second gas exhaust manifold (20) are also For the diagonal setting, the first and second gas intake manifolds (17), (18) and the first and second gas exhaust manifolds (19), (20) are all connected to the gas flow passage surface (11). The tank (13) is connected, and the coolant enters the lane (15) and the coolant The outflow channel (16) is in communication with the groove (13) of the coolant flow passage surface (12); in addition, the gas flow passage surface (11) may further be provided with a gastight structure (115), and the airtight structure (115) The system is disposed around the first gas intake manifold (17) and the first gas exhaust manifold (19) so as not to communicate with the groove (13) of the gas flow passage surface (11), or the airtight structure (115) is disposed around the second gas intake manifold (18) and the second gas exhaust manifold (20) so as not to communicate with the groove (13) of the gas flow passage surface (11); That is, the airtight structure (115) between the first partition plate (1a) and the membrane electrode group (2) is disposed on the second gas intake manifold (18) and the second gas exhaust manifold (20) Around the airtight structure (115) between the second partition plate (1b) and the membrane electrode assembly (2) is disposed on the first gas intake manifold (17) and the first gas exhaust manifold (19) around; wherein, in this embodiment, the airtight junction (115) may be a gasket, or silicone may be applied to the place where the airtight structure (115) is located, and is not limited thereto; further, the airtight structure (115) of the embodiment is further set. The coolant enters the channel (15) and the coolant outflow channel (16), and is disposed around the gas channel face (11) to avoid leakage of fuel gas.

In the actual implementation of the above preferred embodiment, please refer to the fourth figure, which is a perspective exploded view of the dual battery structure of the preferred embodiment. First, the partition plate (1) of the present invention is The metal substrate (which may be, for example, made of stainless steel) has a thickness of about 0.002 to 0.02 inches. The processing method uses stamping to extrude the desired flow path and fluid into and out of the manifold. The separator (1) can be used as both a cathode flow channel and an anode flow channel, thereby saving design and processing production costs; and the practical application of the fuel cell is generally to connect a plurality of fuel cell units in series to form a fuel cell stack to obtain sufficient The power generated in the fuel cell stack, the adjacent partition plates (1) are joined to each other by the corresponding coolant flow passage surface (12), and the contact between the partition plate (1) and the partition plate (1) is generated. The barrier, and the contactless groove (13) forms a straight flow path (121) capable of transporting the coolant (please refer to the fifth to seventh figures together), wherein the two partition plates (1) are Welding joint or conductive adhesive bonding, and welding may have different welding methods such as laser welding, argon welding, arc welding, oxyacetylene welding; this embodiment is to weld the two partition plates (1) by laser spot welding, because of laser welding (LBW) has the advantages of high energy density, low heat input and small heat influence, which can effectively reduce the occurrence of hot cracking and weld sensitization of the weld bead. Therefore, the bonding of the thin metal separator (1) is the best way. And the solder joints are used for transferring electrons between the partition plates (1); further, in the embodiment, the gas flow passage surface (11) has nine gas flow paths, that is, except for the uppermost end a first gas flow path (111) and a lowermost second gas flow path (112), and a total of seven third gas flow paths (113) between the first and second gas flow paths (111) and (112) In addition, the total lengths of the first gas flow path (111), the second gas flow path (112), and the third gas flow path (113) are the same, and the total number of bends (114) of each gas flow path is also The same, making The body flow channel surface (11) forms nine cluster-shaped blocks of respective turns; it is worth noting that the number of gas flow paths is only a preferred embodiment thereof, and the reading and understanding of the creation is guided. Thereafter, the skilled artisan knows that the number of the second gas flow paths (112) of the present creation may be less than seven or more than seven, without affecting the implementation of the present creation.

Referring to FIG. 8 again, a schematic diagram of gas and coolant flow distribution of the fuel cell stack according to the preferred embodiment of the present invention is provided, wherein the separator plates (1) of the above preferred embodiment are respectively disposed on conventional thin film electrodes. After the two ends of the group (2), a fuel gas (for example, hydrogen) is introduced through the first gas intake manifold (17) of the first partition plate (1a), and through the first to third gas flow paths ( 111), (112), (113) uniformly diffuse throughout the gas flow path surface (11), so that the fuel gas can be sufficiently reacted with the thin film electrode assembly (2) and then discharged through the first gas exhaust manifold (19). The dotted line "--" indicates the path of the fuel gas; and the oxygen (air) is introduced through the second gas inlet manifold (18) of the second partition plate (1b) through the first to third gas flow paths ( 111), (112), (113) uniformly diffuse throughout the gas flow path surface (11), so that oxygen (air) can also be fully reacted with the thin film electrode group (2) and then exhausted through the second gas The channel (20) is discharged, wherein the dot line "---" indicates the path of oxygen (air); for the coolant, when the outer sides of the two separator plates (1) are superposed on each other, a grid-like straight line is generated. The flow channel (121) can reduce the resistance of the coolant flowing in the linear flow channel (121), so as to effectively cool the fuel cell, thereby stabilizing the operating temperature of the battery, avoiding excessive temperature and affecting battery performance or even causing components Damage, where the solid line "-" indicates the path of the coolant; here, the thin film electrode set (2) is well known in the art and is not the focus of this creation, so the internals thereof will not be described The principle of construction and its chemical reaction.

In summary, the solar power supply system of the present invention has the following advantages:

1. The partition plate of the creation is formed by the arrow-shaped blocks formed by the first, second and third gas flow passages of the crucible, so that the fuel gas and the oxidant can be uniformly distributed on the gas flow passage surface, ensuring sufficient reaction gas. The concentration enters the membrane electrode group to fully react with the membrane electrode assembly, thereby improving the power generation efficiency of the fuel cell.
2. The present invention forms a fuel gas flow path by forming a metal partition plate in a plurality of press forming processes, and the metal substrate (which may be stainless steel) has a small thickness and a light weight, which not only reduces the volume of the fuel cell but also achieves light weight. To quantify the need, and only need to design (open the mold) a separator plate that can be used for the anode and cathode of the fuel cell (the first partition plate and the second partition plate), so as to avoid the need for two conventional fuel cells. A differently designed separator plate effectively reduces the manufacturing cost of the fuel cell.
3. The fuel cell stack of the present invention utilizes adjacent partition plates to join the coolant flow passage surfaces to form a straight flow passage for conveying coolant, reducing the resistance of the coolant flowing in the straight flow passage, and avoiding cooling in the fuel cell stack. The problem of blockage of the agent effectively achieves the need to cool the fuel cell, thereby stabilizing the operating temperature of the battery, and avoiding excessive temperature and affecting battery performance and even causing component damage.
4. The partition plate of the creation is matched with the corresponding airtight structure, which not only makes the gas inlet and outlet be diagonally arranged, but also increases the effect of the gas evenly distributed on the gas flow channel surface, and also prevents the fuel gas and the coolant from leaking into the environment. Causes battery performance degradation and damage, and even safety problems caused by leakage.

However, the illustrations and descriptions disclosed above are only preferred embodiments of the present invention, and are not intended to limit the scope of protection of the present invention; those who are familiar with the skill are otherwise characterized by the scope of the creation. Equivalent changes or modifications shall be considered as not departing from the design of this creation.

(1) ‧ ‧ partition board (1a) ‧ ‧ first partition

(1b)‧‧‧Second partition plate (11) ‧‧‧ gas passage surface

(111)‧‧‧First gas flow path (112)‧‧‧second gas flow path

(113) ‧‧‧ Third gas flow path (114) ‧ ‧ bend

(115) ‧ ‧ airtight structure (12) ‧ ‧ coolant channel surface

(121) ‧‧‧Linear runners (13)‧‧‧ trenches

(14) ‧ ‧ cutting edge

(15) ‧‧‧ coolant enters the lane

(16) ‧‧‧ coolant outflow manifold

(17)‧‧‧First gas intake manifold

(18)‧‧‧Second gas intake manifold

(19) ‧‧‧First gas exhaust manifold

(20)‧‧‧Second gas exhaust manifold

(2) ‧‧‧Thin electrode group

The first figure: a schematic exploded view of the unit cell structure of the preferred embodiment of the present invention

Second Figure: Schematic diagram of the gas flow path surface of the single cell separator plate of the preferred embodiment of the present invention

Fig. 3 is a plan view showing the coolant flow path surface of the single cell separator plate of the preferred embodiment of the present invention

Fourth figure: a three-dimensional exploded view of the dual battery structure of the preferred embodiment of the present invention

Fig. 5 is a cross-sectional view showing a double-cell structure of the preferred embodiment of the present invention in which a coolant flow path surface is joined to form a straight flow path

Figure 6 is a cross-sectional view showing another embodiment of the dual battery structure of the preferred embodiment in which the coolant flow path faces are joined to form a straight flow path.

Figure 7: Description of the coolant straight flow path of the double battery structure of the preferred embodiment of the present invention

Figure 8 is a schematic diagram showing the distribution of gas and coolant flow in a fuel cell stack of the preferred embodiment of the present invention.

(1)‧‧‧ partition board

(1a)‧‧‧First partition

(1b)‧‧‧Second divider

(11) ‧‧‧ gas flow surface

(115) ‧ ‧ airtight structure

(12) ‧‧‧ coolant channel surface

(15) ‧‧‧ coolant enters the lane

(16) ‧‧‧ coolant outflow manifold

(17)‧‧‧First gas intake manifold

(18)‧‧‧Second gas intake manifold

(19) ‧‧‧First gas exhaust manifold

(20)‧‧‧Second gas exhaust manifold

(2) ‧‧‧Thin electrode group

Claims (10)

The fuel cell stack separator has a gas flow passage surface formed by press working and a coolant flow passage surface corresponding to the gas flow passage surface, and the gas flow passage surface and the coolant flow passage surface have corresponding opposite depressions a plurality of grooves alternated with the protrusions, the groove of the gas flow path surface is formed with a first gas flow path, a second gas flow path, and a plurality of grooves between the first gas flow path and the second gas flow path a third gas flow channel, the first, second, and third gas flow channels each have a plurality of bends, and the two bending connecting lines of the first and second gas flow paths are respectively a linear shape and an arrow shape, and The two bending connecting lines of the third gas flow path are all in the shape of a corresponding arrow cluster, and the tips of the arrow cluster shapes are located on the same horizontal line; when the two partition plates are joined by the coolant flow channel surface, the two cooling The groove of the agent flow passage surface forms a straight flow path for conveying the coolant. The fuel cell stack partition plate according to claim 1, wherein a corresponding coolant inlet passage and a coolant outflow passage are respectively disposed at the center of the two side ends of the partition plate, and the coolant enters the manifold. The first gas intake manifold and the second gas intake manifold are respectively disposed on the two sides of the pipeline, and the first gas exhaust manifold and the second gas exhaust manifold are respectively disposed on two sides of the coolant outflow manifold. The first gas intake manifold and the first gas exhaust manifold are diagonally disposed, and the second gas intake manifold and the second gas exhaust manifold are also diagonally disposed, and the The first and second gas intake manifolds and the first and second gas exhaust manifolds are all in communication with the groove of the gas flow passage surface, the coolant entering the manifold and the coolant outflow manifold and the coolant The grooves of the runner surface are connected. The fuel cell stack separator according to claim 2, wherein a gas tight structure is further disposed on the gas flow passage surface, and the airtight structure is disposed on the first gas intake manifold and the first The gas exhaust manifold is disposed not to communicate with the groove of the gas flow passage surface, or the airtight structure is disposed around the second gas intake manifold and the second gas exhaust manifold It is not in communication with the groove of the gas flow passage surface. The fuel cell stack separator according to claim 3, wherein the airtight structure is further disposed around the coolant inlet manifold and the coolant outflow channel, and is disposed on the gas flow channel surface. Around it, avoid leakage of fuel gas. The fuel cell stack separator according to claim 1, wherein the first gas flow path, the second gas flow path, and the third gas flow path have the same total length. The fuel cell stack separator according to claim 1, wherein the first gas flow path, the second gas flow path, and the third gas flow path have the same total number of bends. The fuel cell stack separator according to claim 1, wherein the partition plate is a metal substrate. The fuel cell stack separator according to claim 7, wherein the metal substrate is stainless steel. The fuel cell stack separator according to claim 1, wherein the two partition plates are bonded by a solder joint or a conductive paste, and the solder joints of the solder joints transmit electrons between the partition plates. The fuel cell stack is formed by a plurality of fuel cell units connected in series, and the fuel cell unit comprises:
a conventional membrane electrode assembly (MEA); and two separator plates respectively disposed at two side ends of the membrane electrode group, the separator panel being as claimed in any one of claims 1 to 9 The fuel cell stack separator plate.