A bipolar plate and solid oxide electrolytic cell stack and applications thereof

Abstract

The present invention discloses a bipolar plate and a solid oxide electrolytic cell stack and applications thereof, comprising an upper fixed plate, a lower fixed plate, an insulating plate, an upper collector plate, a lower collector plate and a plurality of single cell repeating units located between the upper and lower collector plates; the single cell repeating unit comprises a bipolar plate, a cathode collector grid, an anode collector grid, a membrane electrode and a sealing material; the upper collector plate is connected to the anode collector grid of the uppermost single cell repeating unit, and the lower collector plate is connected to the cathode collector grid of the lowermost single cell repeating unit; the upper collector plate is separated from the upper fixed plate by an insulating plate, and the lower collector plate is separated from the lower fixed plate by an insulating plate. The electrolytic cell stack of the present invention has a simple sealing structure, is not prone to failure problems, and has higher reliability.

Description

Technical Field

[0001] The present invention relates to the field of solid oxide electrolytic cells, and in particular to a bipolar plate and a solid oxide electrolytic cell stack and applications thereof. Background Art

[0002] The solid oxide electrolyzer is the reverse process of the solid oxide fuel cell. It has a fully solid structure and can avoid the evaporation, corrosion and electrolyte loss problems caused by the use of liquid electrolytes. It does not require the use of precious metal electrodes and has a lower preparation cost. It operates at high temperatures (above 700°C) and can couple industrial waste heat, with an electrical efficiency of 100%. The solid oxide electrolyzer can electrolyze water vapor to produce hydrogen, electrolyze carbon dioxide to produce carbon monoxide, and electrolyze water vapor / carbon dioxide to produce synthesis gas, etc., and has broad application prospects.

[0003] The solid oxide electrolytic cell stack is the core component of the system. Compared with the tubular electrolytic cell stack, the flat-plate electrolytic cell stack has a higher electrolysis current density and is currently a hot topic of research. However, the flat-plate electrolytic cell stack has higher requirements for sealing and current collection, and it is easy to have sealing failure problems, resulting in poor reliability. In the prior art, the assembly of the solid oxide electrolytic cell stack includes the sealing between the membrane electrode and the battery frame, the sealing between the battery frame and the bipolar plate, and the sealing between the bipolar plates. There are many sealing surfaces involved, and it is easy to have sealing failure problems, resulting in the inability of the entire electrolytic cell stack to operate. Summary of the invention

[0004] In order to overcome the problem of difficult sealing of a solid oxide electrolytic cell stack, the present invention provides a bipolar plate and an electrolytic cell stack structure that is easy to seal.

[0005] A bipolar plate, the bipolar plate is provided with an anode surface and a cathode surface, the cathode surface of the bipolar plate is provided with a cathode gas distribution groove and a cathode sealing material filling groove, the anode surface of the bipolar plate is provided with an anode gas distribution groove and an anode sealing material filling groove, the cathode gas distribution groove and the anode gas distribution groove of the bipolar plate are grooves on both sides of the bipolar plate and are inwardly concave, and the bottoms are respectively provided with gas flow channels;

[0006] The cathode sealing material filling groove and the anode sealing material filling groove on the bipolar plate are distributed around the gas inlet and outlet;

[0007] The cathode gas distribution groove and the anode gas distribution groove of the bipolar plate are surrounded by sealing material filling grooves, which are used to seal the membrane electrode.

[0008] A solid oxide electrolytic cell stack, the electrolytic cell stack sequentially comprising an upper fixing plate, a first insulating plate, an upper current collecting plate, a plurality of single cell repeating units, a lower current collecting plate, a second insulating plate, and a lower fixing plate;

[0009] The single-cell repeating unit includes a bipolar plate, a cathode collector network, a membrane electrode, and an anode collector network in sequence, wherein the bipolar plate is provided with an anode surface and a cathode surface, the cathode surface of the bipolar plate is provided with a cathode gas distribution groove and a cathode sealing material filling groove, and the anode surface of the bipolar plate is provided with an anode gas distribution groove and an anode sealing material filling groove.

[0010] The cathode gas distribution groove and the anode gas distribution groove of the bipolar plate are grooves on both sides of the bipolar plate and are recessed inwards, used to accommodate the collector plate and the membrane electrode, and gas flow channels are respectively provided at the bottom.

[0011] The cathode collector grid and the anode collector grid are respectively placed in the cathode gas distribution groove and the anode gas distribution groove, the membrane electrode cathode is connected to the cathode collector grid, the membrane electrode anode is connected to the anode collector grid, the cathode collector grid is connected to the cathode surface of the bipolar plate, and the anode collector grid is connected to the anode surface of the next bipolar plate; the cathode sealing material filling groove and the anode sealing material filling groove are filled with sealing material; the membrane electrode is directly encapsulated into the cathode gas distribution groove and the anode gas distribution groove of two adjacent bipolar plates.

[0012] Furthermore, in the above technical solution, an anode gas distribution groove is provided on one side of the upper collector plate; the anode gas distribution groove of the upper collector plate is connected to the anode collector network of the topmost single-cell repeating unit, and a cathode gas distribution groove is provided on one side of the lower collector plate, and the cathode gas distribution groove of the lower collector plate is connected to the cathode collector network of the bottommost single-cell repeating unit; the membrane electrode is encapsulated in the anode gas distribution groove of the upper collector plate and the cathode gas distribution groove of the adjacent bipolar plate; the membrane electrode is encapsulated in the cathode gas distribution groove of the lower collector plate and the anode gas distribution groove of the adjacent bipolar plate.

[0013] Furthermore, in the above technical solution, the bipolar plate has a thickness of 0.5 mm to 3 mm, preferably 1.5 mm to 2 mm.

[0014] Furthermore, in the above technical solution, the upper collector plate of the electrolytic cell stack has a side with an anode gas distribution groove provided with a sealing material filling groove, and the lower collector plate has a side with a cathode gas distribution groove provided with a sealing material filling groove; the sealing material filling grooves of the upper collector plate are distributed around the gas inlet and outlet; the sealing material filling grooves of the lower collector plate are distributed around the gas inlet and outlet; the anode gas distribution groove of the upper collector plate is provided with sealing material filling grooves around the inside; the cathode gas distribution groove of the lower collector plate is provided with sealing material filling grooves around the inside; and they are used to seal the membrane electrode.

[0015] Furthermore, in the above technical solution, the upper collector plate and the upper fixed plate of the electrolytic cell stack are separated by a first insulating plate, and the lower collector plate and the lower fixed plate are separated by a second insulating plate. The first insulating plate and the second insulating plate can be one of an alumina ceramic plate, a zirconia ceramic plate, a mica plate, and an asbestos plate.

[0016] Furthermore, in the above technical solution, the upper fixing plate and the lower fixing plate of the electrolytic cell stack are connected by bolts.

[0017] Furthermore, in the above technical solution, both the cathode gas and the anode gas of the electrolytic cell stack can be recovered.

[0018] Further, in the above technical solution, the cathode sealing material filling groove and the anode sealing material filling groove of two adjacent bipolar plates are sealed together by a sealing material;

[0019] Furthermore, in the above technical solution, the anode sealing material filling groove of the upper collector plate and the cathode sealing material filling groove of the topmost bipolar plate are sealed together by sealing material; the cathode sealing material filling groove of the lower collector plate and the anode sealing material filling groove of the bottom bipolar plate are sealed together by sealing material.

[0020] Furthermore, in the above technical solution, the electrolytic cell stack is suitable for electrolyzing water vapor, electrolyzing carbon dioxide, electrolyzing water vapor and carbon dioxide, and electrolyzing hydrocarbon fuels.

[0021] The beneficial effects of the present invention are as follows: the assembly process of the existing flat-plate electrolytic cell stack includes sealing between the membrane electrode and the battery frame, sealing between the battery frame and the bipolar plate, and sealing between the bipolar plates. There are many sealing surfaces involved, and the problem of sealing failure is prone to occur, resulting in the inability of the entire electrolytic cell stack to operate. The electrolytic cell stack of the present invention contains a bipolar plate that can directly encapsulate the membrane electrode. The assembly of the electrolytic cell stack only involves sealing between the membrane electrode and the bipolar plate, and sealing between the bipolar plates. The sealing area is small and the reliability is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the electrolytic cell stack of Example 1;

[0023] Figure 2 Schematic diagram of the bipolar plate structure;

[0024] In the figure, 1 is an upper fixing plate, 2 is a first insulating plate, 3 is an upper current collecting plate, 4 is an anode collecting grid, 5 is a membrane electrode, 6 is a cathode collecting grid, 7 is a bipolar plate, 8 is a lower current collecting plate, 9 is a second insulating plate, and 10 is a lower fixing plate;

[0025] 11 cathode sealing material filling slot, 12 cathode gas distribution slot, 13 anode gas distribution slot, 14 anode sealing material filling slot. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0027] Example 1

[0028] Take a set of electrolytic cell stacks as an example, the structure is as shown in the attached Figure 1 As shown, it includes an upper fixing plate 1, a first insulating plate 2, an upper current collecting plate 3, 5 single-cell repeating units, a lower current collecting plate 8, a second insulating plate 9, and a lower fixing plate 10 in sequence.

[0029] The single cell repeating unit includes bipolar plates, cathode collector grid, membrane electrode, and anode collector grid in sequence.

[0030] The bipolar plate 7 is made of 430 stainless steel with a thickness of 1.5 mm. The cathode collector grid 6 is made of nickel foam, the anode collector grid 4 is made of Ag mesh, and the membrane electrode 5 is an anode-supported membrane electrode with a composition of NiO-YSZ / / YSZ / / LSCF. The effective electrode area is about 80 cm 2 , the sealing material is a modified sodium silicate ceramic oxide. Among them, the anode surface and the cathode surface are set on both sides of the bipolar plate, the anode surface of the bipolar plate is arranged with an anode gas distribution groove and an anode sealing material filling groove, and the cathode surface of the bipolar plate is arranged with a cathode gas distribution groove and a cathode sealing material filling groove, and the depth of the anode sealing material filling groove and the cathode sealing material filling groove is 0.2-0.3mm. The cathode gas distribution groove and the anode gas distribution groove of the bipolar plate are grooves on both sides of the bipolar plate and are concave inward, which are used to accommodate the collector plate and the membrane electrode, and the bottom is respectively provided with a gas flow channel; the upper collector plate 3 and the lower collector plate 8 are made of 430 stainless steel with a thickness of 8mm. The upper collector plate 3 is provided with an anode gas distribution groove and a sealing material filling groove on one side, and the lower collector plate 8 is provided with a cathode gas distribution groove and a sealing material filling groove on one side, and the depth of the sealing material filling groove is 0.2-0.3mm. The membrane electrode is directly packaged into the cathode gas distribution groove and the anode gas distribution groove of two adjacent bipolar plates; the upper fixed plate 1 and the lower fixed plate 10 are made of 310 stainless steel with a thickness of 10 mm. The first insulating plate 2 between the upper fixed plate 1 and the upper collector plate 3 is an alumina ceramic plate with a thickness of 2 mm, and the second insulating plate 9 between the lower fixed plate and the lower collector plate is a mica plate with a thickness of 5 mm.

[0031] The anode gas distribution groove of the upper collector plate is connected to the anode collector network of the uppermost single-cell repeating unit, and the cathode gas distribution groove of the lower collector plate is connected to the cathode collector network of the lowermost single-cell repeating unit; the anode gas distribution groove of the upper collector plate is provided with sealing material filling grooves around the inside; the cathode gas distribution groove of the lower collector plate is provided with sealing material filling grooves around the inside; the sealing material is used to seal the membrane electrode; the membrane electrode is packaged in the anode gas distribution groove of the upper collector plate and the cathode gas distribution groove of the adjacent bipolar plate; the membrane electrode is packaged in the cathode gas distribution groove of the lower collector plate and the anode gas distribution groove of the adjacent bipolar plate.

[0032] The stack assembly process is as follows: place the lower fixing plate on the mounting table, place the second insulating plate 9 on the lower fixing plate, place the lower collector plate on the second insulating plate 9, place the side of the lower collector plate with the cathode gas distribution groove on the top and connected to the cathode collector grid of the first single-cell repeating unit, and then place the single-cell repeating units in sequence, wherein the cathode collector grid and the anode collector grid are placed in the cathode gas distribution groove and the anode gas distribution groove respectively, the membrane electrode anode is connected to the anode collector grid, the anode collector grid is connected to the anode surface of the next bipolar plate, until the anode collector grid of the last repeating unit is connected to the upper collector plate. The anode gas distribution slot of the upper collector plate is connected; the first insulating plate and the upper fixing plate are added on the upper collector plate, and the upper fixing plate and the lower fixing plate are connected by bolts. After pressurization, the distance between the upper fixing plate and the lower fixing plate is reduced to the specified distance, and the cathode sealing material filling slot and the anode sealing material filling slot of the two adjacent bipolar plates are sealed together by sealing materials; the sealing material filling slot of the upper collector plate is sealed together with the cathode sealing material filling slot of the uppermost bipolar plate and the sealing material; the sealing material filling slot of the lower collector plate is sealed together with the anode sealing material filling slot of the lower bipolar plate; a complete electrolytic cell stack is formed. The electrolytic cell stack has good airtightness, and there is no cross-talk between the cathode and anode gases.

[0033] The electrolytic cell stack was tested in the water vapor electrolysis mode: the electrolysis current density was -43A at 800°C and 1.3V, and the hydrogen production rate reached 90L / h.

[0034] Example 2

[0035] A solid oxide electrolytic cell stack, the electrolytic cell stack sequentially comprising an upper fixing plate 1, a first insulating plate 2, an upper current collecting plate 3, a single cell repeating unit, a lower current collecting plate 8, a second insulating plate 9, and a lower fixing plate 10;

[0036] The single-cell repeating unit includes a bipolar plate, a cathode collector network, a membrane electrode, and an anode collector network in sequence, wherein the bipolar plate is provided with an anode surface and a cathode surface, the cathode surface of the bipolar plate is provided with a cathode gas distribution groove and a cathode sealing material filling groove, and the anode surface of the bipolar plate is provided with an anode gas distribution groove and an anode sealing material filling groove.

[0037] The cathode gas distribution groove and the anode gas distribution groove of the bipolar plate are grooves on both sides of the bipolar plate and are inwardly concave, and gas flows are respectively arranged at the bottom.

[0038] The cathode collector grid and the anode collector grid are respectively placed in the cathode gas distribution groove and the anode gas distribution groove, the membrane electrode cathode is connected to the cathode collector grid, the membrane electrode anode is connected to the anode collector grid, the cathode collector grid is connected to the cathode surface of the bipolar plate, and the anode collector grid is connected to the anode surface of the next bipolar plate; the cathode sealing material filling groove and the anode sealing material filling groove are filled with sealing material; the membrane electrode is directly encapsulated into the cathode gas distribution groove and the anode gas distribution groove of two adjacent bipolar plates.

[0039] Furthermore, in the above technical scheme, an anode gas distribution groove is provided on one side of the upper collector plate; the anode gas distribution groove of the upper collector plate is connected to the anode collector network of the uppermost single-cell repeating unit, and a cathode gas distribution groove is provided on one side of the lower collector plate, and the cathode gas distribution groove of the lower collector plate is connected to the cathode collector network of the lowermost single-cell repeating unit; sealing material filling grooves are provided around the inside of the anode gas distribution groove of the upper collector plate; sealing material filling grooves are provided around the inside of the cathode gas distribution groove of the lower collector plate; used to fill the sealing material to seal the membrane electrode; the membrane electrode is encapsulated in the anode gas distribution groove of the upper collector plate and the cathode gas distribution groove of the adjacent bipolar plate; the membrane electrode is encapsulated in the cathode gas distribution groove of the lower collector plate and the anode gas distribution groove of the adjacent bipolar plate.

[0040] The bipolar plate has a thickness of 0.5 mm to 3 mm, preferably 1.5 mm to 2 mm.

[0041] The upper collector plate of the electrolytic cell stack has a sealing material filling groove on one side with the anode gas distribution groove, and the lower collector plate has a sealing material filling groove on one side with the cathode gas distribution groove.

[0042] The upper collector plate and the upper fixing plate of the electrolytic cell stack are separated by a first insulating plate, and the lower collector plate and the lower fixing plate are separated by a second insulating plate. The first insulating plate and the second insulating plate can be one of an alumina ceramic plate, a zirconia ceramic plate, a mica plate, and an asbestos plate.

[0043] The upper fixing plate and the lower fixing plate of the electrolytic cell stack are connected by bolts. The cathode sealing material filling slot and the anode sealing material filling slot of two adjacent bipolar plates are sealed together by sealing materials; the sealing material filling slot of the upper collector plate and the cathode sealing material filling slot of the uppermost bipolar plate are sealed together by sealing materials; the sealing material filling slot of the lower collector plate and the anode sealing material filling slot of the lowermost bipolar plate are sealed together by sealing materials.

[0044] Both cathode gas and anode gas of the electrolytic cell stack can be recovered.

[0045] The electrolytic cell stack is suitable for electrolyzing water vapor, electrolyzing carbon dioxide, electrolyzing water vapor and carbon dioxide, and electrolyzing hydrocarbon fuels.

Claims

1. A solid oxide electrolytic cell stack, characterized in that: The electrolytic cell stack comprises, in sequence, an upper fixing plate, a first insulating plate, an upper current collecting plate, a plurality of single-cell repeating units, a lower current collecting plate, a second insulating plate, and a lower fixing plate; The single cell repeating unit includes bipolar plates, cathode collector grid, membrane electrode, and anode collector grid in sequence; The bipolar plate is provided with an anode surface and a cathode surface, a cathode gas distribution groove and a cathode sealing material filling groove are provided on the cathode surface of the bipolar plate, and an anode gas distribution groove and an anode sealing material filling groove are provided on the anode surface of the bipolar plate. The cathode gas distribution groove and the anode gas distribution groove of the bipolar plate are grooves that are inwardly concave on both sides of the bipolar plate, and gas flow channels are provided at the bottom respectively; the cathode sealing material filling groove and the anode sealing material filling groove on the bipolar plate are distributed around the gas inlet and outlet; the cathode gas distribution groove and the anode gas distribution groove of the bipolar plate are provided with sealing material filling grooves around the inside thereof; The cathode collector grid and the anode collector grid are respectively placed in the cathode gas distribution groove and the anode gas distribution groove, the membrane electrode cathode is connected to the cathode collector grid, the membrane electrode anode is connected to the anode collector grid, the cathode collector grid is connected to the cathode surface of the bipolar plate, and the anode collector grid is connected to the anode surface of the next bipolar plate; the cathode sealing material filling groove and the anode sealing material filling groove are filled with sealing material; the membrane electrode is directly encapsulated into the cathode gas distribution groove and the anode gas distribution groove of two adjacent bipolar plates.

2. The solid oxide electrolytic cell stack according to claim 1, characterized in that: An anode gas distribution groove is provided on one side of the upper collector plate; the anode gas distribution groove of the upper collector plate is connected to the anode collector grid of the uppermost single-cell repeating unit, and a cathode gas distribution groove is provided on one side of the lower collector plate, and the cathode gas distribution groove of the lower collector plate is connected to the cathode collector grid of the lowermost single-cell repeating unit; the membrane electrode is encapsulated in the anode gas distribution groove of the upper collector plate and the cathode gas distribution groove of the adjacent bipolar plate; the membrane electrode is encapsulated in the cathode gas distribution groove of the lower collector plate and the anode gas distribution groove of the adjacent bipolar plate.

3. The solid oxide electrolytic cell stack according to claim 1, characterized in that: The bipolar plate has a thickness of 0.5 mm to 3 mm.

4. The solid oxide electrolytic cell stack according to claim 2, characterized in that: The upper collector plate of the electrolytic cell stack has a sealing material filling groove on one side with an anode gas distribution groove, and a sealing material filling groove on the side with a cathode gas distribution groove; the sealing material filling grooves of the upper collector plate are distributed around the gas inlet and outlet; the sealing material filling grooves of the lower collector plate are distributed around the gas inlet and outlet; the anode gas distribution groove of the upper collector plate is provided with sealing material filling grooves around the inside; the cathode gas distribution groove of the lower collector plate is provided with sealing material filling grooves around the inside.

5. The solid oxide electrolytic cell stack according to claim 1, characterized in that: The upper collector plate and the upper fixing plate of the electrolytic cell stack are separated by a first insulating plate, and the lower collector plate and the lower fixing plate are separated by a second insulating plate. The first insulating plate and the second insulating plate are selected from one of an alumina ceramic plate, a zirconia ceramic plate, a mica plate, and an asbestos plate.

6. The solid oxide electrolytic cell stack according to claim 1, characterized in that: The upper fixing plate and the lower fixing plate of the electrolytic cell stack are connected by bolts.

7. The solid oxide electrolytic cell stack according to claim 1, characterized in that: Both cathode gas and anode gas of the electrolytic cell stack can be recovered.

8. The solid oxide electrolytic cell stack according to claim 1, characterized in that: The cathode sealing material filling groove and the anode sealing material filling groove of two adjacent bipolar plates are sealed together by a sealing material; The sealing material filling groove of the upper collector plate is sealed together with the cathode sealing material filling groove of the uppermost bipolar plate by the sealing material; The sealing material filling groove of the lower collector plate and the anode sealing material filling groove of the lowermost bipolar plate are sealed together by the sealing material.

9. The use of a solid oxide electrolysis cell stack according to any one of claims 1 to 8, wherein the electrolysis cell stack is suitable for electrolysis of water vapor, electrolysis of carbon dioxide, electrolysis of water vapor and carbon dioxide, and electrolysis of hydrocarbon fuels.

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