Bipolar plate, electric pile and fuel cell

Abstract

The present invention relates to the technical field of bipolar plates, and discloses a bipolar plate, an electric pile and a fuel cell, the bipolar plate comprises a bipolar plate body, the bipolar plate body is provided with at least one main flow field, the main flow field is provided with a plurality of flow channels, the two sides of the main flow field are respectively provided with a gas inlet, a cooling liquid inlet, a gas outlet and a cooling liquid outlet, the gas inlet and the cooling liquid inlet are formed in one side of the main flow field, and the gas outlet and the cooling liquid outlet are formed in the other side of the main flow field. According to the scheme provided by the invention, the main flow field is divided into two parts under the condition that the total reaction area is not changed, the hydrogen-air-water inlet is formed in the middle of the flow field, the hydrogen-air-water outlets are formed in the two sides of the flow field, and the two flow fields share one inlet, so that the fluid distribution of the two flow fields can be effectively improved, and the total flow resistance is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of bipolar plates, and in particular to a bipolar plate, a battery stack and a fuel cell. Background Art

[0002] The bipolar plate is mainly composed of a mainstream field, a distribution area, a sealing groove, and gas and liquid inlets and outlets. The fuel cell stack is assembled by bipolar plates. The more bipolar plates there are, the more gas volume entering each bipolar plate will change. The longer the stack length, the lower the uniformity of gas distribution to each bipolar plate. The design of the inlet and outlet structure will also affect the consistency of gas distribution between bipolar plates. Bipolar plates usually design the inlet and outlet area and size to be the same. The larger the inlet and outlet, the higher the consistency of gas distribution.

[0003] Patent number CN116072908A, patent name bipolar plate, proposes to increase the number of inlets and segment the flow field into multiple reaction areas to ensure that the fluid pressures of some inlets or outlets in multiple reaction areas are the same, thereby achieving roughly the same fluid distribution in multiple reaction areas, thereby solving the problem of uneven fluid distribution in large-area bipolar plates.

[0004] However, too many inlets will increase the difficulty of the process and the tolerance will also increase. More inlets solve the problem of reduced flow resistance, but it may also lead to a decrease in the performance of the bipolar plate, and to achieve the same inlet flow, the distribution design requirements at the front end of the manifold are higher; and by increasing the number of inlets to reduce the flow resistance and thus increase the reaction area, the volume power density of the bipolar plate will be reduced, resulting in a decrease in the utilization rate of the bipolar plate. Summary of the invention

[0005] In order to solve the problem in the prior art that the volume power density and utilization rate of the bipolar plate are reduced by increasing the number of inlets on the bipolar plate to ensure uniform distribution of the flow field fluid, the present invention provides a bipolar plate, a stack and a fuel cell.

[0006] The technical solution of the present invention is as follows:

[0007] A bipolar plate comprises a bipolar plate body, wherein at least one mainstream field is arranged on the bipolar plate body, a plurality of flow channels are arranged on the mainstream field, a gas inlet, a coolant inlet, a gas outlet and a coolant outlet are arranged on both sides of the mainstream field, the gas inlet and the coolant inlet are arranged on one side of the mainstream field, and the gas outlet and the coolant outlet are arranged on the other side of the mainstream field.

[0008] Furthermore, two mainstream fields are arranged on the bipolar plate body, the two mainstream fields are connected in parallel, the gas inlet and the coolant inlet are arranged between the two mainstream fields, and the two mainstream fields are provided with a gas outlet and a coolant outlet on one side away from the gas inlet and the coolant inlet.

[0009] Furthermore, the flow channel period on the mainstream field is less than 1 mm.

[0010] Furthermore, the length of the gas inlet is not less than the length of the gas outlet, and the length of the coolant inlet is not less than the length of the coolant outlet.

[0011] Furthermore, the gas inlet width and the coolant inlet width are not greater than the gas outlet width and the coolant outlet width.

[0012] Furthermore, the width of the gas outlet and the width of the coolant outlet are not greater than twice the width of the gas inlet and the width of the coolant inlet.

[0013] Furthermore, the gas inlet includes a hydrogen inlet and an air inlet, and the hydrogen inlet and the air inlet are respectively arranged on the upper and lower sides of the coolant inlet.

[0014] Furthermore, the gas outlet includes a hydrogen outlet and an air outlet, and the air outlet and the hydrogen outlet are respectively arranged on the upper and lower sides of the coolant outlet.

[0015] The present invention further provides a battery stack, comprising any of the bipolar plates described above.

[0016] The present invention also provides a fuel cell, comprising the fuel cell stack described above.

[0017] The beneficial effects of the present invention include: the scheme provided by the present invention divides the mainstream field into two while ensuring that the total reaction area remains unchanged, and a hydrogen, air and water inlet is set in the middle of the flow field, and hydrogen, air and water outlets are set on both sides. The two flow fields share one inlet, which can effectively improve the fluid distribution of the two flow fields and reduce the total flow resistance; at the same time, the flow velocities of several flow channels in the flow field remain unchanged, and the flow rates entering the flow channels are also the same, which effectively improves the distribution of the main pipe; compared with the single inlet and single outlet of the traditional bipolar plate, the bipolar plate provided by the present invention has a single inlet and double outlets, and the size ratio of the inlet and outlet is optimized, so that the flow distribution between the bipolar plate sheets is more uniform, and the consistency of the flow distribution between the sheets is effectively provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of the bipolar plate provided by the present invention.

[0019] Figure 2 A schematic diagram of the air flow direction structure of the bipolar plate provided by the present invention.

[0020] Figure 3 This is a schematic diagram of the size structure of the inlet and outlet of the bipolar plate provided by the present invention.

[0021] in:

[0022] 1-hydrogen inlet; 2-coolant inlet; 3-air inlet; 4, 7-air outlet; 5, 8-coolant outlet; 6, 9-hydrogen outlet; 10-first mainstream field; 11-second mainstream field; 12-bipolar plate body. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] The present embodiment provides a bipolar plate, including a bipolar plate body 12, on which at least one mainstream field is arranged, on which a plurality of flow channels are arranged, and on both sides of the mainstream field are respectively provided a gas inlet, a coolant inlet, a gas outlet and a coolant outlet, wherein the gas inlet and the coolant inlet are arranged on one side of the mainstream field, and the gas outlet and the coolant outlet are arranged on the other side of the mainstream field.

[0026] The gas inlet comprises a hydrogen inlet and an air inlet, which are respectively arranged on the upper and lower sides of the coolant inlet; the gas outlet comprises a hydrogen outlet and an air outlet, which are respectively arranged on the upper and lower sides of the coolant outlet.

[0027] The mainstream flow field on the bipolar plate is a dense flow field, and a number of flow channels of the same size are arranged.

[0028] Example 2

[0029] Combination Figure 1-3 As described in Example 1, this embodiment provides a bipolar plate. When the designed flow resistance in the mainstream field is greater than twice the required flow resistance, two mainstream fields are arranged on the bipolar plate body 12, that is, a large whole mainstream field is divided into two smaller mainstream fields in parallel. The total reaction area remains unchanged. After the mainstream field is divided into two, the total flow resistance of the bipolar plate is reduced, so that it has two reaction zones, namely the first mainstream field 10 and the second mainstream field 11.

[0030] The first mainstream field 10 is connected in parallel with the second mainstream field 11, and the gas inlet and coolant inlet 2 are arranged between the two mainstream fields. The two mainstream fields are provided with gas outlets and coolant outlets 5 and 8 on one side away from the gas inlet and coolant inlet, thereby optimizing the single-inlet and single-outlet form of the traditional bipolar plate into a single-inlet and double-outlet form, thereby effectively improving the consistency between the battery stack sheets.

[0031] The two smaller mainstream fields provided in this embodiment share the same inlet, which can effectively improve the fluid distribution of the first mainstream field 10 and the second mainstream field 11. When the flow channels on the first mainstream field 10 and the second mainstream field 11 are the same, the flow rates entering the two flow fields through the inlets are also the same, which can effectively improve the distribution of the main pipe.

[0032] Furthermore, the flow channel period on the mainstream field is less than 1 mm, the flow rate and velocity in each flow channel remain unchanged, and mass transfer and gas diffusion are not affected. After the overall flow resistance is divided into two, the overall flow resistance of the bipolar plate is reduced.

[0033] In order to improve the consistency of manifold distribution, the size ratio of the inlet and outlet is adjusted to make the flow distribution between the slices more uniform. Specifically:

[0034] The length of the gas inlet is not less than the length of the gas outlet, and the length of the coolant inlet 2 is not less than the length of the coolant outlets 5 and 8.

[0035] The width of the gas inlet and the width of the coolant inlet 2 are not greater than the width of the gas outlet and the width of the coolant outlets 5 and 8.

[0036] The width of the gas outlet and the width of the coolant outlets 5 and 8 are not greater than twice the width of the gas inlet and the width of the coolant inlet 2.

[0037] The gas inlet comprises a hydrogen inlet 1 and an air inlet 3 , and the hydrogen inlet 1 and the air inlet 3 are respectively arranged on the upper and lower sides of the coolant inlet 2 .

[0038] The gas outlets include hydrogen outlets 6, 9 and air outlets 4, 7. The air outlets 4, 7 and hydrogen outlets 6, 9 are arranged on the upper and lower sides of the coolant outlets 5, 8, respectively.

[0039] like Figure 3 As shown, a is the lateral size of the three-cavity opening, b, c, d are the longitudinal sizes of the cavities for hydrogen, coolant and air respectively, the sizes of b, c, d are adjusted according to the needs, a is the key parameter affecting the distribution consistency, different reaction areas and stacking numbers store the best suitable value within this range, the specific proportion design is as follows:

[0040] b1=b2=b3, c1=c2=c3, d1=d2=d3 or b1>b2=b3, c1>c2=c3, d1>d2=d3;

[0041] a2≤a1≤2a2, a2=a3.

[0042] The above-mentioned adjustment of the size ratio of the inlet and outlet is a solution proposed to address the problem of increased length of the battery stack and poor consistency in distribution between plates. When the inlet area is smaller than the outlet area, it can effectively provide consistency in flow distribution between plates.

[0043] Example 3

[0044] According to Example 2, this embodiment provides a fuel cell stack, including any of the bipolar plates described above, including at least one bipolar plate to form a fuel cell stack.

[0045] Example 4

[0046] According to Example 3, this embodiment provides a fuel cell, including the fuel cell stack described above.

[0047] The present invention is suitable for bipolar plates with a dense flow field or a flow field with large flow resistance. It can reduce the flow resistance of the battery stack to a certain extent, improve the consistency of the fluid flow between the sheets of the battery stack through a single inlet and dual outlet, and provide a bipolar plate with one plate and two fields. A single bipolar plate has two reaction areas with a single inlet in the form of diversion on both sides, which is beneficial to the flow distribution of the two mainstream fields and makes the flow distribution more uniform.

[0048] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A bipolar plate, characterized in that: It includes a bipolar plate body, on which at least one mainstream field is arranged, on which a plurality of flow channels are arranged, and on both sides of the mainstream field are respectively provided a gas inlet, a coolant inlet, a gas outlet and a coolant outlet, wherein the gas inlet and the coolant inlet are arranged on one side of the mainstream field, and the gas outlet and the coolant outlet are arranged on the other side of the mainstream field.

2. The bipolar plate according to claim 1, characterized in that: Two mainstream fields are arranged on the bipolar plate body, the two mainstream fields are connected in parallel, the gas inlet and the coolant inlet are arranged between the two mainstream fields, and the two mainstream fields are provided with a gas outlet and a coolant outlet on one side away from the gas inlet and the coolant inlet.

3. The bipolar plate according to claim 2, characterized in that: The flow channel period on the main flow field is less than 1 mm.

4. The bipolar plate according to claim 2, characterized in that: The length of the gas inlet is not less than the length of the gas outlet, and the length of the coolant inlet is not less than the length of the coolant outlet.

5. The bipolar plate according to claim 2, characterized in that: The gas inlet width and the coolant inlet width are not greater than the gas outlet width and the coolant outlet width.

6. The bipolar plate according to claim 2, characterized in that: The width of the gas outlet and the width of the coolant outlet are not greater than twice the width of the gas inlet and the width of the coolant inlet.

7. The bipolar plate according to claim 2, characterized in that: The gas inlet comprises a hydrogen inlet and an air inlet, and the hydrogen inlet and the air inlet are respectively arranged on the upper and lower sides of the coolant inlet.

8. The bipolar plate according to claim 2, characterized in that: The gas outlet comprises a hydrogen outlet and an air outlet, and the air outlet and the hydrogen outlet are respectively arranged on the upper and lower sides of the coolant outlet.

9. A battery stack, characterized in that: Comprising the bipolar plate as described in any one of claims 1 to 8.

10. A fuel cell, characterized in that: Comprising the battery stack as claimed in claim 9.

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