CN111477909A - Gas-permeable bipolar plates for fuel cell stacks, fuel cell stacks - Google Patents

Abstract

The invention provides a gas permeable bipolar plate suitable for a fuel cell stack and a fuel cell stack, comprising: an anode plate, a cathode plate and a cathode gas permeable plate; the cathode plate is arranged on the anode plate and the cathode gas permeable plate between the plates; the cathode gas permeable plate has holes so that the cathode gas flowing through the cathode gas plate in the fuel cell can pass through the cathode gas permeable plate to reach the membrane electrode; the anode plate is provided with an anode plate flow channel, and the cathode gas A cathode plate flow channel is arranged on the ventilation plate. The invention enables the oxygen in the cathode gas to better diffuse into the membrane electrode area pressed by the cathode flow channel ridge in the traditional bipolar plate to participate in the reaction, thereby enhancing the mass transfer of the cathode gas and improving the fuel cell compared with the traditional bipolar plate. Average current density, improve fuel cell power generation performance, suitable for proton exchange membrane fuel cell stack.

Description

Gas-permeable bipolar plates for fuel cell stacks, fuel cell stacks

technical field

The invention relates to the technical field of batteries, in particular to a gas permeable bipolar plate and a fuel cell stack, in particular to a gas permeable bipolar plate and a fuel cell stack suitable for a fuel cell stack.

Background technique

A fuel cell is a power generation device that can directly convert the chemical energy of fuel and oxidant into electrical energy. Since the voltage of a single cell of a hydrogen fuel cell is very low, in order to meet certain power and voltage requirements, it is often necessary to connect multiple cells in series to form a fuel cell stack in practical applications. The fuel cell stack structure includes end plates, current collector plates, bipolar plates, membrane electrodes, seals, and the like. The performance of each single cell affects the overall performance of the entire stack.

Patent document CN107946605A discloses a bipolar plate flow channel manufacturing process and bipolar plate flow channel. The bipolar plate is a structure composed of two polar plates. In a fuel cell stack, two polar plates sandwich a membrane The electrodes form a single cell, and a plurality of single cells are connected in series to form a stack. The bipolar plate has the following functions: one is to connect the cells in series, the other is to isolate the gas in the adjacent cells, the third is to serve as a structural support for the stack, the fourth is to transfer heat, and the fifth is to provide a certain structure of flow channels to ensure performance. At present, the metal bipolar plates of fuel cells are all welded by an anode plate and a cathode plate. In a fuel cell, the main functions of the plate flow channel are to conduct electricity and heat, and the second is to transport the reaction gas and discharge the produced water. The ridge of the flow channel is in contact with the carbon paper of the membrane electrode, which plays the role of conducting electrons; the groove of the flow channel transports the reaction gas, and the reaction gas diffuses from the groove of the flow channel to the carbon paper. In order to ensure the performance of the battery, the contact surface between the ridge of the electrode plate flow channel and the carbon paper must ensure a certain contact area and contact pressure, otherwise the gas in the flow channel groove will not be able to diffuse to the part of the flow channel ridge pressing on the membrane electrode. The current density distribution of the fuel cell will be uneven, thereby affecting the performance of the cell. For the current fuel cell stack, due to the existing bipolar plate flow channel structure, the oxygen partial pressure in the membrane electrode region is low, and the gas diffusion is not uniform, thus affecting the performance of the battery.

SUMMARY OF THE INVENTION

In view of the defects in the prior art, the purpose of the present invention is to provide a gas permeable bipolar plate and a fuel cell stack suitable for a fuel cell stack.

A gas permeable bipolar plate suitable for a fuel cell stack provided according to the present invention comprises: an anode plate 11, a cathode plate 13 and a cathode gas permeable plate 12;

The cathode plate 13 is arranged between the anode plate 11 and the cathode gas permeable plate 12;

The cathode gas permeable plate 12 has holes so that the cathode gas flowing through the cathode gas permeable plate 13 in the fuel cell can pass through the cathode gas permeable plate 12 to reach the membrane electrode;

The anode plate 11 is provided with an anode plate flow channel 15 , and the cathode gas permeable plate 12 is provided with a cathode plate flow channel 14 .

Preferably, both the cathode plate 13 and the anode plate 12 include a plurality of flow channel ridges;

The flow channel ridges of the cathode plate 13 protrude toward the side where the cathode gas permeable plate 12 is located, and the cathode plate flow channels 14 are formed between two adjacent flow channel ridges;

The flow channel ridges of the anode plate 11 protrude toward the other side of the side where the cathode gas permeable plate 12 is located, and the anode plate flow channels 15 are formed between two adjacent flow channel ridges;

The back surfaces of the flow channel ridges of the cathode plate 13 and the anode plate 11 constitute cooling medium flow channels 16 .

Preferably, the ratio of the width of the flow channel ridge to the flow channel of the cathode plate 13 is 0.1-10.

Preferably, both the cathode plate 13 and the anode plate 11 include corresponding positions: a shunt area 8 , a flow field area 9 , an anode manifold port 2 , a cathode manifold port 3 , an anode branch port 5 and a cathode branch port 6;

The flow channel ridge is located in the flow field region 9;

The anode reactant gas enters the anode plate flow channel 15 of the flow field region 9 of the anode plate 11 after passing through the anode manifold port 2, the anode branch port port 5, and the distribution area 8 in sequence;

The cathode reactant gas enters the cathode plate flow channel 14 of the flow field area 9 of the cathode plate 13 through the cathode manifold port 3, the cathode branch port 6, and the distribution area 8 in sequence, and then passes through the cathode gas permeable plate 12 and diffuses into the membrane electrode.

Preferably, both the cathode plate 13 and the anode plate 11 include: a water manifold port 4 and a moisture pipe port 7 corresponding to their positions;

The cooling medium enters the cooling medium flow channel 16 between the anode plate 11 and the cathode plate 13 after passing through the water manifold port 4 , the moisture pipe port 7 and the distribution area 8 in sequence.

Preferably, the cathode gas permeable plate 12 covers the flow field region 9 of the cathode plate 13 .

Preferably, the shape of the holes on the cathode gas permeable plate 12 includes: circle, ellipse, polygon, waist-shaped hole or irregular shape hole.

Preferably, the anode plate 11 , the cathode plate 13 and the cathode gas permeable plate 12 are fixedly connected together.

A fuel cell stack provided according to the present invention includes a gas permeable bipolar plate suitable for the fuel cell stack.

Preferably, the anode plate 11 is in contact with the anode of the membrane electrode, and the cathode gas permeable plate 12 and the cathode plate 13 are in contact with the cathode of the membrane electrode.

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

1. The position of the cathode gas permeable plate is the gas flow side of the cathode plate. To be precise, it is sandwiched between the membrane electrode and the cathode plate in the fuel cell. The contact area between the ridge of the cathode flow channel and the membrane electrode is increased. According to this method, the problem of excessive pressure on the gas diffusion layer of the membrane electrode caused by the narrowing of the flow channel ridge of the cathode plate can be effectively solved and the membrane electrode is damaged. Solve the problem of excessive contact resistance caused by the narrowing of the cathode plate, and improve the power generation efficiency of the fuel cell.

2. The narrowing of the flow channel ridge of the cathode plate and the widening of the groove can reduce the area of the compression area of the cathode flow channel ridge on the membrane electrode, so that the oxygen in the cathode gas can better diffuse to the membrane electrode to participate in the reaction.

3. The gas permeable bipolar plate with three-layer structure effectively solves the problem that exists in the current conventional bipolar plate, the oxygen concentration in the membrane electrode area corresponding to the cathode flow channel ridge is low due to the shielding of the flow channel ridge, which leads to fuel The problem of lower battery performance. The efficiency of the diffusion of the cathode gas to the membrane electrode is improved, thereby improving the power generation efficiency of the fuel cell.

Description of drawings

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

1 is a plan view of a breathable bipolar plate;

Figure 2 is an exploded view of a breathable bipolar plate;

Fig. 3 is the sectional view of the first kind of opening structure;

4 is a cross-sectional view of a second type of opening structure;

FIG. 5 is a cross-sectional view of a third opening structure.

Detailed ways

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

Example 1

As shown in FIG. 1 and FIG. 2 , a gas permeable bipolar plate suitable for a fuel cell stack provided in this embodiment includes an anode manifold port 2 , a cathode manifold port 3 , a water manifold port 4 , and an anode branch port 5 , Cathode branch port 6, moisture pipe port 7, shunt area 8, flow field area 9, sealing area 10. As shown in FIG. 2 , the gas permeable bipolar plate of the present invention is mainly divided into three parts, which are an anode plate 11 , a cathode gas permeable plate 12 and a cathode plate 13 respectively.

The anode plate structure of the present invention includes an anode manifold port 2, a cathode manifold port 3, a water manifold port 4, an anode manifold port 5, a cathode manifold port 6, a moisture manifold port 7, a shunt area 8, a flow field area 9, a seal District 10. The anode plate is processed by stamping.

The structure of the cathode plate 13 of the present invention includes an anode manifold port 2 , a cathode manifold port 3 , a water manifold port 4 , an anode manifold port 5 , a cathode manifold port 6 , a moisture manifold port 7 , a shunt area 8 , and a sealing area 10 . The ridges of the flow channels in the flow field region 9 of the cathode plate 13 are narrowed and the grooves are widened, and the specific ratio can be modified according to the needs of use. The shielding area of the ridges of the modified flow channel region 9 to the membrane electrode is reduced, and the oxygen in the cathode gas can better diffuse to all parts of the membrane electrode and the cathode to participate in the reaction. The processing method of the cathode plate 13 is stamping. The processing material of the cathode plate 13 includes but is not limited to stainless steel, pure titanium, titanium alloy and the like.

The cathode gas permeable plate 12 mainly includes a flow field area 9. The cathode gas permeable plate 12 is processed with dense small holes, so that the cathode can pass through the cathode gas permeable plate 12 to reach the membrane electrode to participate in the reaction. The processing method of the cathode gas permeable plate 12 may be punching, laser cutting, wire cutting, or the like. The processing materials of the cathode gas permeable plate 12 include but are not limited to stainless steel, pure titanium, titanium alloy, etc., and the processing materials of the cathode gas permeable plate 12 and the cathode plate 13 can be the same material or different materials. The connection method of the cathode gas permeable plate 12 and the cathode plate 13 includes, but is not limited to, welding, gluing, mechanical limit or direct pressure contact. The connection method between the cathode plate 13 and the anode plate includes but is not limited to welding, gluing, and the like.

The anode plate mainly plays the role of sealing the anode gas, evenly distributing the anode gas, evenly distributing the water flow field and conducting electricity. The cathode structure is decomposed into two parts, namely the cathode plate and the cathode gas permeable plate. The cathode plate mainly plays the role of sealing the cathode gas, evenly distributing the cathode gas, evenly distributing the water flow field and conducting electricity. The cathode gas permeable plate mainly plays the role of transitioning the membrane electrode and the cathode plate and conducting electricity.

During the use of the fuel cell gas permeable bipolar plate of the present invention, the gas permeable bipolar plate composed of the anode plate 11, the cathode gas permeable plate 12 and the cathode plate 13 is stacked with the fuel cell membrane electrode to form a fuel cell stack. The anode plate 11 is in contact with the anode of the membrane electrode, and the cathode gas permeable plate 12 and the cathode plate 13 are in contact with the cathode of the membrane electrode. The anode reactant gas passes through the anode manifold port 2 , the anode branch port 5 , and the distribution area 8 in sequence, and then enters the flow field area 9 to participate in the reaction. The cathode reactant gas passes through the cathode manifold port 3, the cathode branch port 6, and the shunt area 8 in sequence, and then enters the cathode plate 13 flow field area 9, and then passes through the cathode gas permeable plate 12, and diffuses into the membrane electrode to participate in the reaction. The cooling medium enters the cooling medium flow channel 16 between the anode plate 11 and the cathode plate 13 after passing through the water manifold port 4 , the moisture pipe port 7 , and the distribution area 8 in sequence, and plays a cooling role.

In the above-mentioned gas permeable bipolar plate, the cathode gas permeable plate material includes but is not limited to stainless steel, titanium alloy, pure titanium, etc., and the cathode gas permeable plate material and the cathode plate material can use the same or different materials. The cathode plate and the cathode gas permeable plate can be combined together, and the combination methods include but are not limited to welding, gluing, mechanical limit or direct pressure contact. The cathode plate can be combined with the anode plate to form a bipolar plate, and the combination methods include but are not limited to welding, gluing, and the like.

As shown in FIG. 3 , on the basis of Example 1, the openings on the cathode gas permeable plate 12 are circular openings. The present invention does not limit the shape of the openings of the cathode gas permeable plate 12, and the shape and size of the openings are beneficial to enable the cathode gas to diffuse to the membrane electrode to participate in the reaction.

The gas permeable bipolar plate provided by the present invention is suitable for the proton exchange membrane fuel cell stack.

Variation 1

As shown in FIG. 4 , on the basis of the basic embodiment, the openings on the cathode ventilation plate 12 are polygonal openings. The present invention does not limit the shape of the openings of the cathode gas permeable plate 12, and the shape and size of the openings are beneficial to enable the cathode gas to diffuse to the membrane electrode to participate in the reaction.

Variation 2

As shown in FIG. 5 , on the basis of the basic embodiment, the openings on the cathode ventilation plate 12 are waist-shaped openings. The present invention does not limit the shape of the openings of the cathode gas permeable plate 12, and the shape and size of the openings are beneficial to enable the cathode gas to diffuse to the membrane electrode to participate in the reaction.

In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", The orientation or positional relationship indicated by "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying the indicated device. Or elements must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as a limitation of the present application.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essential content of the present invention. The embodiments of the present application and features in the embodiments may be combined with each other arbitrarily, provided that there is no conflict.

Claims (10)

1. A gas permeable bipolar plate suitable for a fuel cell stack, characterized in that it comprises: an anode plate (11), a cathode plate (13) and a cathode gas permeable plate (12); The cathode plate (13) is arranged between the anode plate (11) and the cathode gas permeable plate (12); The cathode gas permeable plate (12) has holes so that the cathode gas flowing through the cathode gas permeable plate (13) in the fuel cell can pass through the cathode gas permeable plate (12) to reach the membrane electrode; The anode plate (11) is provided with an anode plate flow channel (15), and the cathode gas permeable plate (12) is provided with a cathode plate flow channel (14). 2. The gas-permeable bipolar plate suitable for a fuel cell stack according to claim 1, wherein the cathode plate (13) and the anode plate (12) both comprise a plurality of flow channel ridges; The flow channel ridges of the cathode plate (13) protrude toward the side where the cathode gas permeable plate (12) is located, and the cathode plate flow channels (14) are formed between two adjacent flow channel ridges; The flow channel ridge of the anode plate (11) protrudes toward the other side of the side where the cathode gas permeable plate (12) is located, and the anode plate flow channel (15) is formed between two adjacent flow channel ridges; The back surfaces of the flow channel ridges of the cathode plate (13) and the anode plate (11) constitute cooling medium flow channels (16). 3. The gas permeable bipolar plate suitable for a fuel cell stack according to claim 2, wherein the ratio of the width of the flow channel ridge to the flow channel of the cathode plate (13) is 0.1-10. 4. The gas-permeable bipolar plate suitable for a fuel cell stack according to claim 1, characterized in that, the cathode plate (13) and the anode plate (11) both comprise: a shunt area ( 8), flow field area (9), anode manifold port (2), cathode manifold port (3), anode manifold port (5) and cathode manifold port (6); The flow channel ridge is located in the flow field region (9); The anode reactant gas enters the anode plate flow channel (15) of the flow field region (9) of the anode plate (11) after passing through the anode manifold port (2), the anode branch port (5), and the flow distribution area (8) in sequence; The cathode reactant gas enters the cathode plate flow channel (14) of the flow field region (9) of the cathode plate (13) after passing through the cathode manifold port (3), the cathode branch port (6), and the distribution area (8) in sequence, and then passes through the cathode plate flow channel (14) of the flow field area (9) of the cathode plate (13). Through the cathode gas permeable plate (12), diffuse into the membrane electrode. 5. The gas-permeable bipolar plate suitable for a fuel cell stack according to claim 4, wherein the cathode plate (13) and the anode plate (11) both comprise a water manifold corresponding in position mouth (4) and water pipe mouth (7); The cooling medium enters the cooling medium flow channel (16) between the anode plate (11) and the cathode plate (13) after passing through the water manifold port (4), the moisture pipe port (7) and the distribution area (8) in sequence. 6. The gas permeable bipolar plate suitable for a fuel cell stack according to claim 4, wherein the cathode gas permeable plate (12) covers the flow field region (9) of the cathode plate (13) )superior. 7. The gas-permeable bipolar plate suitable for a fuel cell stack according to claim 1, wherein the shape of the hole on the cathode gas-permeable plate (12) comprises: circle, ellipse, polygon, waist shape Holes or irregularly shaped holes. 8. The gas permeable bipolar plate suitable for a fuel cell stack according to claim 1, wherein the anode plate (11), the cathode plate (13) and the cathode gas permeable plate (12) are fixed connected. 9 . A fuel cell stack, characterized in that it comprises the gas permeable bipolar plate suitable for a fuel cell stack according to any one of claims 1 to 8 . 10. The fuel cell stack according to claim 9, wherein the anode plate (11) is in contact with the anode of the membrane electrode, and the cathode gas permeable plate (12) and the cathode plate (13) are in contact with the membrane electrode. The cathode contacts of the electrodes.

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