Solid oxide fuel cell and stack

Abstract

The invention discloses a solid oxide fuel cell unit and a cell stack, and the cell unit comprises a first connecting plate, a second connecting plate and a cell metal support ring connected between the first connecting plate and the second connecting plate. A concave pressing ring bearing groove and a battery bearing through groove formed in the pressing ring bearing groove are formed in one side, close to the first connecting plate, of the battery metal supporting ring; a battery piece is arranged in the battery bearing through groove, and a gap is formed between the periphery of the battery piece and the inner side wall of the battery bearing through groove; an opening of the gap is covered with an annular buffering sealing piece, the outer edge part of the annular buffering sealing piece is attached to the surface of the groove bottom of the pressing ring bearing groove, and the inner edge part of the annular buffering sealing piece is attached to the surface of the side, close to the first connecting plate, of the battery piece. A porous ceramic pressing ring is pressed between the first connecting plate and the annular buffering sealing piece in an abutting mode, so that the annular buffering sealing piece seals an opening of the gap.

Description

Technical Field

[0001] The present invention relates to the technical field of solid oxide fuel cells, and in particular to a solid oxide fuel cell unit and a cell stack. Background Art

[0002] Solid oxide fuel cells (SOFC), solid oxide electrolysis cells (SOEC), and reversible solid oxide cells (RSOC) need to undergo thermal cycles during actual operation. For extended-range SOFCs used in transportation, the number of thermal cycles is the most frequent; for RSOCs used for energy storage, there is also a high possibility of thermal cycles depending on weather conditions.

[0003] SOC stack refers to solid oxide fuel cell stack. During the thermal cycle of SOC stack, a major challenge is the inconsistency of thermal expansion coefficient between the battery and the connecting plate. This inconsistency may induce thermal stress, which in turn has the potential risk of causing the electrolyte membrane in the battery cell to rupture. In particular, in recent years, with the pursuit of high current density, the electrolyte membrane has been designed to be thinner and thinner, which has led to a significant reduction in the tensile stress it bears, making it very easy to rupture during thermal cycling.

[0004] Among the traditional sealing methods, one is a completely fastened type, which uses glass ceramic sealing materials. For example, the anode gasket and cathode gasket in the Chinese patent "A Solid Oxide Fuel Cell Stack" with publication number CN218975482U are both made of glass ceramic sealing materials. This sealing method performs well in terms of sealing effect, but it does not have a stress release mechanism. Therefore, during the thermal cycle, the battery cell may be warped or damaged, which will not only reduce its performance, but also cause its electrolyte membrane to rupture, thereby causing damage to the entire battery stack; the other is a compression seal, which uses multi-layer inorganic materials such as mica and vermiculite. These inorganic materials achieve sealing effects through their own deformation under a certain positive pressure. Although this structure has a certain slip mechanism that can relieve lateral thermal stress, its sealing effect is not satisfactory, and it is difficult to achieve a completely sealed state. In addition, it is difficult to control the positive pressure, and the positive pressure required for sealing may cause the battery to break.

[0005] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgement or any form of suggestion that the information constitutes the prior art already known to ordinary technicians in this field. Summary of the invention

[0006] Purpose of the invention: The technical problem to be solved by the present invention is to provide a solid oxide fuel cell unit and a battery stack in view of the deficiencies in the prior art, which can not only achieve complete sealing but also resist thermal cycle stress and meet the frequent thermal cycle requirements of the battery stack.

[0007] In order to solve the above technical problems, the present invention discloses a solid oxide fuel cell unit, which includes a first connecting plate, a second connecting plate and a battery metal support ring directly or indirectly connected between the first connecting plate and the second connecting plate, wherein the battery metal support ring is formed with a concave pressure ring bearing groove and a battery bearing through groove formed in the pressure ring bearing groove on the inner circle of one side close to the first connecting plate. A battery sheet is arranged in the battery bearing through groove, and a gap is arranged between the outer periphery of the battery sheet and the inner side wall of the battery bearing through groove. The opening of the gap is covered with an annular buffer seal, the outer edge of the annular buffer seal is attached to the groove bottom surface of the pressure ring bearing groove, and the inner edge of the annular buffer seal is attached to the side surface of the battery sheet close to the first connecting plate. The porous ceramic pressure ring is arranged in the pressure ring bearing groove, and is pressed between the first connecting plate and the annular buffer seal, so that the annular buffer seal closes the opening of the gap.

[0008] Specifically, the annular buffer seal comprises a deformable buffer ring portion, the buffer ring portion is located in the gap, and the outer edge portion, the buffer ring portion and the inner edge portion are connected in sequence to form the annular buffer seal.

[0009] Specifically, the buffer ring portion is a groove ring structure, and its cross-sectional shape is U-shaped.

[0010] Specifically, the annular buffer seal is made of a ductile metal material, preferably silver.

[0011] Specifically, the distance between the bearing surface of the battery bearing through groove and the bottom of the pressure ring bearing groove is consistent with the thickness of the battery sheet. Correspondingly, the side surface of the porous ceramic pressure ring close to the annular buffer seal is set as a plane.

[0012] Furthermore, the battery cell also includes a first insulating sealing ring and a second insulating sealing ring, wherein the first insulating sealing ring is arranged between the battery metal support ring and the first connecting plate, and the second insulating sealing ring is arranged between the battery metal support ring and the second connecting plate.

[0013] Specifically, the first insulating sealing ring and the second insulating sealing ring are both made of glass ceramic material.

[0014] Specifically, a first current collecting film is arranged on one side of the battery cell close to the first connecting plate, and a first gas flow channel structure is arranged on one side of the first connecting plate close to the battery cell. The first gas flow channel structure is located on the inner side of the porous ceramic pressure ring and contacts the first current collecting film.

[0015] Specifically, a second current collecting film is disposed on a side of the battery cell close to the second connecting plate, a second gas flow channel structure is disposed on a side of the second connecting plate close to the battery cell, and the second gas flow channel structure contacts the second current collecting film.

[0016] Specifically, the first connecting plate, the first insulating sealing ring, the battery metal support ring, the second insulating sealing ring and the second connecting plate are provided with a first air inlet hole, a first air outlet hole, a second air inlet hole and a second air outlet hole, and the groove wall of the pressure ring bearing groove is provided with a first air inlet channel and a first air outlet channel, and the first air inlet hole, the first air inlet channel, the first gas flow channel structure, the first air outlet channel and the first air outlet hole are connected in sequence to form a first air channel. The groove wall of one end of the battery bearing groove close to the second connecting plate is provided with a second air inlet channel and a second air outlet channel, and the second air inlet hole, the second air inlet channel, the second gas flow channel structure, the second air outlet channel and the second air outlet hole are connected in sequence to form a second air channel.

[0017] Specifically, the first air inlet and the first air outlet are symmetrically arranged, and the second air inlet and the second air outlet are symmetrically arranged.

[0018] Specifically, the first current collecting film is an air electrode current collecting film, the second current collecting film is a fuel electrode current collecting film, the first air channel is used for air to flow through, and the second air channel is used for fuel gas to flow through.

[0019] The present invention also provides a solid oxide fuel cell stack, which includes the solid oxide fuel cell unit as described above.

[0020] Beneficial effects:

[0021] 1. The solid oxide fuel cell unit provided by the present invention is provided with an annular buffer seal at the gap between the battery metal support ring and the periphery of the battery cell to cover the opening of the gap, and the porous ceramic pressure ring is pressed against the annular buffer seal to stably isolate the two opposite sides of the battery cell in an airtight manner. Specifically, the gap provides a thermal expansion space in the lateral direction of the battery cell under thermal shock to prevent the battery cell from warping under thermal shock; the annular buffer seal itself can be deformed to adapt to the change in the gap width under thermal cycle shock, to achieve a stable compression seal between the battery cell and the annular buffer seal and between the annular buffer seal and the battery metal support ring, and then combined with the high temperature seal of the battery metal support ring between the first connecting plate and the second connecting plate, the overall stable airtight isolation of the two opposite sides of the battery cell under thermal cycle is achieved.

[0022] 2. In the present invention, the battery cell and the annular buffer seal, as well as the annular buffer seal and the battery metal support ring are compressed and sealed by a high-strength porous ceramic pressure ring. The positive pressure required for sealing is borne by the high-strength porous ceramic pressure ring, which has little impact on the battery.

[0023] 3. An embodiment of the present invention provides an annular buffer seal with a deformable buffer ring portion between its outer edge portion and inner edge portion, and the deformable buffer ring portion can be arranged in a gap, and the gap provides a deformation space for the buffer ring portion. When the thermal cycle needs to release stress, the expansion and contraction of the buffer ring portion provides stress release space for the battery cell.

[0024] 4. The present application may adopt a secondary sealing method, the process of which is to first assemble the battery metal support ring, battery cell, annular buffer seal and porous ceramic pressure ring and perform high-temperature sealing connection after assembly, that is, to achieve anti-gas seal, and then assemble the first connecting plate, the first insulating sealing ring, the second connecting plate, the second insulating sealing ring and the aforementioned components together and perform high-temperature sealing connection after assembly, that is, to achieve anti-leakage seal. Compared with primary sealing, secondary sealing can avoid the misalignment problem during the assembly of multiple components during the primary sealing process. In addition, the secondary sealing method has clear sealing goals by handling leakage and blowby separately, and it is easy to achieve a high level of quality management. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0026] Figure 1 An exploded view of a solid oxide fuel cell unit provided for a first embodiment of the present invention;

[0027] Figure 2 for Figure 1A top view of a solid oxide fuel cell unit is shown;

[0028] Figure 3 For along Figure 2 Sectional view taken along line AA;

[0029] Figure 4 for Figure 3 A partial enlarged view of the cross-sectional view shown;

[0030] Figure 5 For along Figure 2 Sectional view along the midline BB;

[0031] Figure 6 for Figure 5 A partial enlargement of the cross-sectional view shown.

[0032] Figure 7 A partially enlarged cross-sectional view of a solid oxide fuel cell unit provided in accordance with a second embodiment of the present invention.

[0033] The description of the accompanying drawings is:

[0034] 1. First connecting plate; 2. Second connecting plate; 3. Battery metal support ring; 31. Pressure ring bearing groove; 32. Battery bearing through groove; 4. Battery cell; 5. Porous ceramic pressure ring; 6. Annular buffer seal; 61. Outer edge portion; 62. Inner edge portion; 63. Buffer ring portion; 7. First current collecting membrane; 8. Second current collecting membrane; 9. First insulating sealing ring; 10. Second insulating sealing ring; 11. First gas flow channel structure; 12. First air inlet; 13. First air outlet; 14. Second air inlet; 15. Second air outlet; 16. First air inlet channel; 17. First air outlet channel; 18. Second air inlet channel; 19. Second air outlet channel; 21. Second gas flow channel structure. DETAILED DESCRIPTION

[0035] Example 1

[0036] Figure 1 This is an exploded view of a solid oxide fuel cell unit provided in Example 1 of the present invention. Figure 2 for Figure 1 A top view of a solid oxide fuel cell unit is shown. Figure 3 and Figure 5 For along Figure 2 The cross-sectional view obtained by cutting along the AA and BB lines. Figure 3 and Figure 5 The part of the porous ceramic pressure ring 5 where the gas flow channel structure can be seen is not shown.

[0037] Combination Figures 1 to 6As shown, an embodiment of the present invention provides a solid oxide fuel cell unit. The battery unit includes a first connecting plate 1, a second connecting plate 2 and a battery metal support ring 3. Figure 6 For example, the first connecting plate 1, the second connecting plate 2 and the battery metal support ring 3 are arranged from top to bottom. The battery metal support ring 3 is directly or indirectly sealed and connected between the first connecting plate 1 and the second connecting plate 2. The battery metal support ring 3 is formed with a concave pressure ring bearing groove 31 and a battery bearing through groove 32 formed in the pressure ring bearing groove 31 on the inner circle of the side close to the first connecting plate 1. A battery cell 4 is arranged in the battery bearing through groove 32, and a gap is arranged between the outer periphery of the battery cell 4 and the inner side wall of the battery bearing through groove 32. The gap is annular as a whole. The opening of the gap is covered with an annular buffer seal 6. The outer edge portion 61 of the annular buffer seal 6 is attached to the bottom surface of the groove of the pressure ring bearing groove 31, and the inner edge portion 62 of the annular buffer seal 6 is attached to the side surface of the battery cell 4 close to the first connecting plate 1. A breathable porous ceramic pressure ring 5 is arranged between the first connecting plate 1 and the annular buffer seal 6, and the porous ceramic pressure ring 5 is arranged in the pressure ring bearing groove 31 and is located above the annular buffer seal 6. The porous ceramic pressure ring 5 is pressed between the first connecting plate 1 and the annular buffer seal 6. The annular buffer seal 6 closes the opening of the gap under the pressure of the porous ceramic pressure ring 5, thereby achieving stable airtight isolation of the upper and lower opposite sides of the battery cell 4, that is, achieving isolation of fuel gas and air, and preventing gas leakage on both sides of the battery cell 4.

[0038] The solid oxide fuel cell unit provided by the present invention can not only achieve complete sealing, but also resist thermal cycle stress, and meet the frequent thermal cycle requirements of the battery stack. Specifically, the annular buffer seal 6 closes the opening of the gap under the pressure of the porous ceramic pressure ring 5 to avoid gas leakage on both sides of the battery cell in a static state; the above-mentioned gap provides thermal expansion space in the lateral direction of the battery cell 4 under thermal shock to avoid the battery cell 4 from warping under thermal shock; at the same time, the annular buffer seal 6 is deformed to adapt to the change in the gap width under thermal cycle shock, and a stable sealed connection between the battery cell and the battery metal support ring and between the annular buffer seal and the battery metal support ring is achieved, that is, the opening of the gap is stably closed during the thermal cycle process to avoid gas leakage on both sides of the battery cell under thermal cycle shock. Combined with the battery metal support ring 3, the sealing connection between the first connecting plate 1 and the second connecting plate 2 finally achieves stable airtight isolation of the two opposite sides of the battery cell 4 under thermal cycle.

[0039] Specifically, in order to match the thermal expansion coefficients, the first connecting plate 1, the second connecting plate 2 and the battery metal support ring 3 are preferably made of the same dense metal material, such as imported Crofer 22 or domestic 430 stainless steel.

[0040] In this embodiment, the first connecting plate 1, the second connecting plate 2 and the battery metal support ring 3 are made of the same material to achieve thermal expansion matching among the three in the lateral direction.

[0041] Specifically, the battery cell may be the battery cell described in patent CN222008079U, and all planar batteries mentioned in the patent may be used in the present application.

[0042] Specifically, the annular buffer seal 6 is made of a metal material with good compactness, good ductility and low hardness, so that it has good plasticity and is easy to deform, and can form a better fit with other components to achieve a sealing effect. Preferably, the annular buffer seal 6 is made of silver, such as S999 sterling silver.

[0043] Specifically, combined Figure 4 As shown, the annular buffer seal 6 includes a deformable buffer ring portion 63, which is located in the gap, so as to use the gap as a receiving space for the buffer ring portion 63 and a deformation space under thermal cycle impact. The outer edge portion 61, the buffer ring portion 63 and the inner edge portion 62 are connected in sequence to form the annular buffer seal 6.

[0044] In some embodiments, in combination Figure 4 As shown, the buffer ring part 63 is a groove ring structure, and its cross-section is U-shaped, and its cross-section opening faces the porous ceramic pressure ring 5. The annular buffer seal 6 of this embodiment can be manufactured by pressing.

[0045] Compared to the flat annular seal, the outer edge portion 61 of the annular buffer seal 6 is stably fitted and connected to the battery metal support ring 3, and the inner edge portion 62 of the annular buffer seal 6 is stably fitted and connected to the battery cell 4. The lateral width of the U-shaped buffer ring portion 63 decreases as the battery cell 4 expands due to temperature rise, and the length in the height direction increases accordingly, thereby adapting to the change in the gap width under thermal shock. In some embodiments, the gap can provide sufficient space for the U-shaped buffer ring portion 63 to undergo the above-mentioned deformation. In some other embodiments, since the material used to prepare the annular buffer seal 6, such as silver, has creep properties at high temperatures, when the size of the gap in the height direction is not enough to accommodate the increased portion of the buffer ring portion 63 in the height direction, the buffer ring portion 63 will change from U-shape to W-shape to adapt to the space size of the gap.

[0046] Specifically, the porous ceramic pressure ring 5 is made of ceramic material with good strength because it needs to withstand pressure, and is also required to have good air permeability to allow gas to pass through the gas chamber on one side of the battery cell.

[0047] Preferably, the porous ceramic pressure ring 5 adopts the ceramic material disclosed in the Chinese patent application "Double-layer porous ceramic plate and its preparation method and application" with publication number CN118751084A. The air permeability of the ceramic material is 60% to 80%, and the mechanical strength is between 0.5Mpa and 2.6Mpa.

[0048] In some embodiments, in combination Figure 4 As shown, the distance between the bearing surface of the battery bearing groove 32 and the bottom of the pressure ring bearing groove 31 is consistent with the thickness of the battery cell 4. Correspondingly, the side surface of the porous ceramic pressure ring 5 close to the annular buffer seal 6 is set to be a plane.

[0049] In this example, the battery sheet 4 inserted into the battery carrying through groove 32 and the groove bottom of the pressure ring carrying groove 31 are located in the same plane, thereby ensuring uniform force and stable sealing.

[0050] In some embodiments, the pressure ring bearing groove 31 and the battery bearing through groove 32 of the battery metal support ring 3 are obtained by machining an integral blank. In some other embodiments, the battery metal support ring 3 is obtained by combining separate metal ring parts and then brazing them.

[0051] Specifically, combined Figure 1 and Figure 3 As shown, a first current collecting film 7 is provided on one side of the battery cell 4 close to the first connecting plate 1 , and a first gas flow channel structure 11 is provided on one side of the first connecting plate 1 close to the battery cell 4 . The first gas flow channel structure 11 is located on the inner side of the porous ceramic pressure ring 5 and contacts the first current collecting film 7 .

[0052] Specifically, combined Figure 1 and Figure 3 As shown, a second current collecting film 8 is disposed on one side of the battery cell 4 close to the second connecting plate 2 , and a second gas flow channel structure 21 is disposed on one side of the second connecting plate 2 close to the battery cell 4 . The second gas flow channel structure 21 contacts the second current collecting film 8 .

[0053] The first gas flow channel structure 11 and the second gas flow channel structure 21 can both adopt structures in the prior art, and their specific compositions are not the main improvement points of the present application, and therefore will not be described in detail here.

[0054] In some embodiments, the depth of the pressure ring bearing groove 31 is equivalent to the thickness of the first gas flow channel structure 11 on the corresponding side, and the distance from the bearing surface of the battery bearing through groove 32 to the end surface of the battery metal support ring 3 close to the second connecting plate 2 is equivalent to the thickness of the second gas flow channel structure 21 on the corresponding side. These clear correspondences bring convenience to the battery stack design and quality management.

[0055] Specifically, in order to realize the sealing connection between the first connecting plate 1 and the second connecting plate 2, the battery metal support ring 3 is combined with Figure 1 and Figure 3 As shown, the battery cell also includes a first insulating sealing ring 9 and a second insulating sealing ring 10. The first insulating sealing ring 9 is arranged between the battery metal support ring 3 and the first connecting plate 1, and the second insulating sealing ring 10 is arranged between the battery metal support ring 3 and the second connecting plate 2. The first insulating sealing ring 9 and the second insulating sealing ring 10 can be made of the same material. The first insulating sealing ring 9 and the second insulating sealing ring 10 are preferably made of glass ceramic material, such as the glass ceramic material produced by the Shanghai Institute of Ceramics, Chinese Academy of Sciences, which is disclosed in the Chinese patent with publication number CN102386345A. Compared with other insulating sealing rings made of vermiculite, mica and other materials used for compression sealing or fastening sealing, the insulating sealing ring made of glass ceramic material used for fully fastened sealing has a better sealing effect.

[0056] Specifically, combined Figures 3 to 6 As shown, the first connecting plate 1, the first insulating sealing ring 9, the battery metal support ring 3, the second insulating sealing ring 10 and the second connecting plate 2 are provided with a first air inlet 12, a first air outlet 13, a second air inlet 14 and a second air outlet 15. Figure 5 The first inlet channel 16 and the first outlet channel 17 are arranged in the groove wall of the pressure ring bearing groove 31. The first inlet hole 12, the first inlet channel 16, the first gas channel structure 11, the first outlet channel 17 and the first outlet hole 13 are connected in sequence to form a first gas channel. Figure 3 A second air inlet channel 18 and a second air outlet channel 19 are provided on the groove wall at one end of the battery carrying groove 32 close to the second connecting plate 2. The second air inlet hole 14, the second air inlet channel 18, the second gas flow channel structure 21, the second air outlet channel 19 and the second air outlet hole 15 are connected in sequence to form a second air channel.

[0057] Specifically, Figure 3 and Figure 5 For example, the first air inlet channel 16, the first air outlet channel 17, the second air inlet channel 18, and the second air outlet channel 19 are all arranged in the transverse direction. Figure 3 The first inlet channel 16 extends from the side groove wall corresponding to the inlet side of the first gas channel structure 11 in the pressure ring bearing groove 31 to the hole wall of the first inlet hole 12. The first outlet channel 17 extends from the side groove wall corresponding to the outlet side of the first gas channel structure 11 in the pressure ring bearing groove 31 to the hole wall of the first outlet hole 13. Figure 5The second inlet channel 18 extends from the side groove wall corresponding to the inlet side of the second gas flow channel structure 21 in the pressure ring bearing groove 31 to the hole wall of the second inlet hole 14. The second outlet channel 19 extends from the side groove wall corresponding to the outlet side of the second gas flow channel structure 21 in the pressure ring bearing groove 31 to the hole wall of the second outlet hole 15.

[0058] Optionally, combined Figure 1 and Figure 2 As shown, the first air inlet 12 and the first air outlet 13 are symmetrically arranged, and the second air inlet 14 and the second air outlet 15 are symmetrically arranged.

[0059] In a specific embodiment, the first air channel is used for air to flow through, and the second air channel is used for fuel to flow through. The first current collecting film is an air electrode current collecting film, and the second current collecting film is a fuel electrode current collecting film.

[0060] The battery cells of this embodiment can be sealed and connected once or twice. Specifically, the process of the single sealing connection is to first place the battery cell 4 in the battery bearing groove 32 of the battery metal support ring 3, and then place the annular buffer seal 6 in the gap between the battery cell 4 and the inner walls around the battery bearing groove 32. The buffer ring portion 63 of the annular buffer seal 6 is accommodated in the gap, and the outer edge portion 61 of the annular buffer seal 6 is attached to the bottom surface of the pressure ring bearing groove 31, and the inner edge portion 62 of the annular buffer seal 6 is attached to the side surface of the battery cell 4 close to the first connecting plate 1. Then the porous ceramic pressure ring 5 is set above the annular buffer seal 6. Then the first connecting plate 1, the first insulating sealing ring 9, the above-mentioned components, the second insulating sealing ring 10 and the second connecting plate 2 are stacked from top to bottom and clamped for high-temperature sealing, see. Figure 6 During high-temperature sealing, the annular buffer seal 6 closes the opening of the gap under the pressure of the porous ceramic pressure ring 5, and the battery metal support ring 3 is sealed between the first connecting plate 1 and the second connecting plate 2, thereby achieving isolation between the inside and outside of the battery unit and anti-gas sealing on both sides of the battery cell 4.

[0061] In the present application, high temperature sealed connection means that the components are clamped at high temperature and after cooling down, the components are connected as a whole.

[0062] There are two ways of secondary sealing. The process of the first secondary sealing method is: first assemble the battery metal support ring 3, the second connecting plate 2 and the second insulating sealing ring 10 and perform high-temperature sealing connection, and then assemble the first connecting plate 1, the first insulating sealing ring 9, the annular buffer seal 6, the porous ceramic pressure ring 5 and the battery cell 4 in the aforementioned assembly and perform high-temperature sealing connection after assembly. The process of the first secondary sealing method is: first assemble the battery metal support ring 3, the battery cell 4, the annular buffer seal 6 and the porous ceramic pressure ring 5 and perform high-temperature sealing connection after assembly, that is, to achieve anti-gas sealing, and then assemble the first connecting plate 1, the first insulating sealing ring 9, the second connecting plate 2, the second insulating sealing ring 10 with the aforementioned assembly together and perform high-temperature sealing connection after assembly, that is, to achieve anti-leakage sealing.

[0063] Compared with primary sealing, secondary sealing can avoid the misalignment problem during the assembly of multiple parts during primary sealing. In addition, the second secondary sealing method can handle leakage and blowby separately, with clear sealing targets and easy to achieve high-level quality management.

[0064] The embodiment of the present invention further provides a solid oxide fuel cell stack, the stack comprising a plurality of the above-mentioned battery cells. The first connecting plate and the second connecting plate of adjacent battery cells can be combined into one part, that is, a full connecting plate in the art. Figure 3 and Figure 5 As shown, a first gas flow channel structure 11 and a second gas flow channel structure 21 are respectively disposed on two opposite sides of the full connection plate.

[0065] Example 2

[0066] Different from the embodiment 1, the buffer ring portion 63 opens toward the first connecting plate 1, see Figure 7 The buffer ring portion 63 of this embodiment may also open toward the second connecting plate 2 , and accordingly, the porous ceramic pressure ring 5 of this embodiment corresponding to the buffer ring portion 63 may be provided with an inward groove to accommodate the buffer ring portion 63 .

[0067] The present invention provides a concept and method for a solid oxide fuel cell unit and a battery stack. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A solid oxide fuel cell unit, characterized in that: include: A first connecting plate (1); A second connecting plate (2); A battery metal support ring (3) connected between the first connecting plate (1) and the second connecting plate (2), wherein the battery metal support ring (3) is formed with an inwardly concave pressure ring bearing groove (31) and a battery bearing through groove (32) formed in the pressure ring bearing groove (31) on an inner circle of a side close to the first connecting plate (1); A battery cell (4) is arranged in the battery carrying groove (32), and a gap is provided between the outer periphery of the battery cell (4) and the inner side wall of the battery carrying groove (32); an annular buffer seal (6) covering the opening of the gap, wherein the outer edge portion (61) of the annular buffer seal (6) is in contact with the bottom surface of the pressure ring bearing groove (31), and the inner edge portion (62) of the annular buffer seal (6) is in contact with the surface of one side of the battery cell (4) close to the first connecting plate (1); and a porous ceramic pressure ring (5) disposed in the pressure ring bearing groove (31), wherein the porous ceramic pressure ring (5) is pressed between the first connecting plate (1) and the annular buffer seal (6), so that the annular buffer seal (6) closes the opening of the gap.

2. The solid oxide fuel cell unit according to claim 1, characterized in that: The annular buffer seal (6) comprises a deformable buffer ring portion (63), wherein the buffer ring portion (63) is located in the gap; the outer edge portion (61), the buffer ring portion (63) and the inner edge portion (62) are connected in sequence to form the annular buffer seal (6).

3. The solid oxide fuel cell unit according to claim 2, characterized in that: The buffer ring part (63) is a groove ring structure, and its cross-sectional shape is U-shaped.

4. The solid oxide fuel cell unit according to claim 3, characterized in that: The material of the annular buffer seal (6) is a ductile metal material, preferably silver.

5. The solid oxide fuel cell unit according to claim 1, characterized in that: The distance between the bearing surface of the battery bearing through groove (32) and the bottom of the pressure ring bearing groove (31) is consistent with the thickness of the battery sheet (4); correspondingly, the surface of one side of the porous ceramic pressure ring (5) close to the annular buffer seal (6) is set to be a plane.

6. The solid oxide fuel cell unit according to claim 1, characterized in that: The battery unit also includes a first insulating sealing ring (9) and a second insulating sealing ring (10), wherein the first insulating sealing ring (9) is arranged between the battery metal support ring (3) and the first connecting plate (1), and the second insulating sealing ring (10) is arranged between the battery metal support ring (3) and the second connecting plate (2).

7. The solid oxide fuel cell unit according to claim 6, characterized in that: The first insulating sealing ring (9) and the second insulating sealing ring (10) are both made of glass ceramic material.

8. The solid oxide fuel cell unit according to claim 6, characterized in that: A first current collecting film (7) is arranged on the side of the battery cell (4) close to the first connecting plate (1), and a first gas flow channel structure (11) is arranged on the side of the first connecting plate (1) close to the battery cell (4), and the first gas flow channel structure (11) is located on the inner side of the porous ceramic pressure ring (5) and contacts the first current collecting film (7); a second current collecting film (8) is arranged on the side of the battery cell (4) close to the second connecting plate (2), and a second gas flow channel structure (21) is arranged on the side of the second connecting plate (2) close to the battery cell (4), and the second gas flow channel structure (21) contacts the second current collecting film (8).

9. The solid oxide fuel cell unit according to claim 8, characterized in that: The first connecting plate (1), the first insulating sealing ring (9), the battery metal support ring (3), the second insulating sealing ring (10) and the second connecting plate (2) are provided with a first air inlet hole (12), a first air outlet hole (13), a second air inlet hole (14) and a second air outlet hole (15); a first air inlet channel (16) and a first air outlet channel (17) are provided in the groove wall of the pressure ring bearing groove (31); the first air inlet hole (12), the first air inlet channel (16), the first air outlet hole (15) and the second air outlet hole (15) are provided in the groove wall of the pressure ring bearing groove (31); A gas flow channel structure (11), a first gas outlet channel (17) and the first gas outlet hole (13) are connected in sequence to form a first gas channel; a second gas inlet channel (18) and a second gas outlet channel (19) are provided on a groove wall at one end of the battery supporting groove (32) close to the second connecting plate (2); the second gas inlet hole (14), the second gas inlet channel (18), the second gas flow channel structure (21), the second gas outlet channel (19) and the second gas outlet hole (15) are connected in sequence to form a second gas channel.

10. A solid oxide fuel cell stack, characterized in that: It comprises the solid oxide fuel cell unit as claimed in claim 1.

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