JP5648378B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack using solid polymer type or solid oxide type unit cells.

As this type of fuel cell stack, there is a configuration disclosed in Patent Document 1.
The fuel cell stack disclosed in Patent Document 1 includes a plurality of unit cells each having a joined body in which an electrolyte is interposed between an anode side electrode and a cathode side electrode, and a set of separators that sandwich the joined body. And at least one of the set of separators has a set of metal plates each having a portion where recesses and projections are alternately continuous, and between the set of metal plates. A leaf spring is interposed.
Further, the above-described plate spring is in contact with the top of each convex portion of the pair of metal plates, and the concave portion of one metal plate and the convex portion of the other metal plate are opposed to each other via the plate spring. It has become.
With the above configuration, it is intended to absorb the change in the unit cell dimensions due to thermal expansion, swelling of the electrolyte membrane, and the like during operation of the fuel cell by elastically deforming the leaf spring.

JP 2002-367665 A

However, in the conventional fuel cell stack, if the pitch of the unit cell is reduced while maintaining the power generation performance, the pitch of the cooling water passage is inevitably reduced together with the pitch of the gas passage.
For this reason, the pitch of the leaf springs is also reduced, and the rigidity of the leaf springs is increased so that a predetermined load and stroke cannot be secured, so that it is difficult to absorb the expansion / contraction deformation of the unit cells, and it is difficult to reduce the pitch of the unit cells. In addition, there is a drawback that the separator and the leaf spring slide relative to each other.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fuel cell stack that can be reduced in size by absorbing expansion / contraction deformation of unit cells even when the stacking pitch of unit cells is reduced.

In the fuel cell stack for achieving the above object, a plurality of unit cells in which a joined body in which an electrolyte is joined between an anode side electrode and a cathode side electrode are sandwiched between a pair of separators are laminated to each other. In a fuel cell stack that generates power by flowing two types of power generation gas separately from each other on both electrodes of each unit cell, the cooling fluid is circulated between the unit cells and the two separators facing each other. A cooling layer for partitioning is formed and laminated, and a conductive deformation absorbing member for absorbing at least electrolyte expansion / contraction deformation of the unit cell is disposed between the separators, and the displacement absorption is performed. In a region where the member is equivalent to the power generation area of the unit cell, a plurality of wave-shaped elastic deformation portions are arranged in a direction intersecting the flow direction of the cooling medium, and elastic The top of the shaped part is made conductive contact with the two separators, and at least a portion of the displacement absorption member, is fixed to them the separators, wherein the separators is a rectangular convex portion to each other the same shape and size , which has a plurality of rectifying portion formed at a constant pitch at the direction crossing the flow direction of the cooling medium, and then define a distribution layer of the cooling layer and the power generation gas, the displacement absorbing member The pitch of the elastic deformation part is larger than the pitch of the rectifying part of the separator, and the top part of the elastic deformation part of the displacement absorbing member is fixed to the separator.

According to the present invention, even when the stacking pitch of the unit cells is reduced, it is possible to reduce the size by absorbing at least electrolyte swelling and expansion / contraction deformation due to drying of the unit cells.
Further, even if the displacement absorbability of the disc spring or the gas diffusion layer is removed, the increase / decrease displacement of the unit cell during operation can be absorbed, and the lamination load necessary for power generation can be stably maintained. Further, by fixing by welding, it is possible to suppress sliding between the separator and the deformation absorbing member and to reduce fluctuations in the surface pressure with respect to the displacement of the unit cell.

1 is an external perspective view of a fuel cell stack according to an embodiment of the present invention. It is a disassembled perspective view of the fuel cell stack which concerns on one Embodiment same as the above. It is a schematic front view of the unit cell which concerns on an example which makes a part of fuel cell stack same as the above. It is a cross-sectional perspective view for demonstrating the cooling layer divided and formed between the unit cells which concern on an example which adjoins, and the deformation | transformation absorption member which concerns on the example inserted by this cooling layer. It is a disassembled perspective view which shows the fixed state of the cooling layer divided and formed between the unit cells which concern on an example which adjoins, the separator which makes a part of the unit cell, and the deformation | transformation absorption member which concerns on an example. It is for demonstrating the cooling layer partition-formed between the unit cells which concern on an adjacent example, and the deformation | transformation absorption member which concerns on the example inserted by this cooling layer, and shows the state which the unit cell expanded and deformed It is a fragmentary sectional view. (A) is the side view of the deformation | transformation absorption member which concerns on an example, (B) is the front view, (C) is the elements on larger scale which expand and show the part shown by the surrounding line I shown to (A). . It is a partial expanded side view which expands and shows partially the deformation | transformation absorption member which concerns on a 1st modification, and the unit cell which concerns on an example which contacts this. It is the partial expansion side view which expands and shows partially the deformation | transformation absorption member which concerns on an example, and the unit cell which concerns on the other example which contacts this. It is a cross-sectional perspective view which shows the fixation aspect of the separator which concerns on another example, and a deformation | transformation absorption member, and simplifies the structure. It is a cross-sectional perspective view which shows the fixation aspect of the separator which concerns on another example, and the deformation | transformation absorption member which concerns on an example, and simplifies and shows the structure. It is a cross-sectional perspective view which shows the fixation aspect of the separator which concerns on another example, and the deformation | transformation absorption member which concerns on an example, and simplifies and shows the structure. It is a cross-sectional perspective view which shows the fixation aspect of the separator which concerns on another example, and the deformation | transformation absorption member which concerns on an example, and simplifies and shows the structure. It is the partial expansion side view which expands and shows partially the deformation | transformation absorption member which concerns on a 2nd modification, and the unit cell which concerns on the other example which contacts this. It is a fragmentary perspective view of the deformation | transformation absorption member which concerns on a 3rd modification. It is a front view of the deformation | transformation absorption member which concerns on a 3rd modification.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated with reference to drawings. FIG. 1 is an external perspective view of a fuel cell stack according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the fuel cell stack, and FIG. 3 is a unit according to an example forming a part of the fuel cell stack. It is a schematic front view of a cell. 4 is a cross-sectional perspective view for explaining a cooling layer partitioned between unit cells according to an example adjacent to each other and a deformation absorbing member interposed in the cooling layer, and FIG. 5 is adjacent to each other. It is a disassembled perspective view which shows the fixed state of the cooling layer divided and formed between the unit cells which concern on an example, the separator which makes a part of the unit cell, and a deformation | transformation absorption member. 4 and 5, one of the pair of separators is omitted.

As shown in FIGS. 1 and 2, a fuel cell stack A according to an embodiment of the present invention includes a case 20 in which a rectangular cell stack B in which unit cells 10 according to a plurality of examples are stacked together is accommodated in a case 20. It is.
The unit cell 10 has a structure in which a joined body 40 is sandwiched between a pair of separators 30 and 31.

  As shown in FIGS. 2, 4, and 5, the separators 30 and 31 are metal plates formed in a rectangular shape in a front view, and long side edges 30b, 30b, 31b, and 31b formed with a constant width between both ends. A plurality of rectifying units 30a and 31a are formed in a required region therebetween.

In order to distribute the hydrogen-containing gas that is one power generation gas, the cooling medium, and the oxygen-containing gas that is the other power generation gas, in the vicinity of both ends, that is, both ends of the regions where the rectifying units 30a and 31a are formed. The inflow holes 32I, 33I, and 34I and the outflow holes 32O, 33O, and 34O are formed in a square shape.
In the present embodiment, hydrogen gas will be described as an example of hydrogen-containing gas, air as oxygen-containing gas, and cooling water as a cooling medium.

  The required region in which the rectifying units 30a and 31a are formed is a surface facing the cooling layer S, the details of which will be described later. In this embodiment, the rectifying units 30a and 31a are rectangular shapes having the same shape and the same size. The protrusions are formed at a constant pitch P1 in the direction orthogonal to the flow direction α shown in FIGS.

  By forming the rectifying portions 30a and 31a in a rectangular shape, the contact area with the deformation absorbing member 50, which will be described in detail later, can be increased, but the shape is not limited to this, and other known shapes may be used. Of course. In short, what is necessary is just to be able to rectify the cooling water flowing through the cooling layer S.

  Hydrogen gas, air, and cooling water flowing from the inflow holes 32I, 33I, and 34I toward the outflow holes 32O, 33O, and 34O are provided at the outer peripheral edges of the inflow holes 32I, 33I, and 34I and the outflow holes 32O, 33O, and 34O. A path forming wall (not shown) for projecting each of them along a required path is projected.

As shown in FIGS. 4 and 5, the joined body 40 has a structure in which an electrolyte 43 is inserted and joined between an anode side electrode 41 and a cathode side electrode 42, and is attached to a frame 44. Note that the frame 44 may be disposed as necessary.
The joined body 40 is configured to generate power by causing the anode side electrode 41 and the cathode side electrode 42 to flow in contact with the two kinds of power generation gases described above.

The frame 44 is formed in a rectangular shape having the same shape and size as the separators 30 and 31, and the inflow holes 32I, 33I, and 34I and the outflow holes 32O, 33O, and 34O are provided at both ends of the frame 44, respectively. A rectangular opening is formed.
In this frame 44, a required region where the joined body 40 is disposed is also referred to as a “power generation area”.

  The anode side electrode 41 and the cathode side electrode 42 are composed of a gas diffusion layer (not shown) made of carbon cloth, carbon paper, or the like, and porous carbon particles carrying a platinum alloy on the surface. The electrode catalyst layers (not shown) are applied to the solid polymer electrolyte membrane 43 so that the electrode catalyst layers face each other with the solid polymer electrolyte membrane 43 therebetween. Yes.

  The solid polymer electrolyte membrane 43 is formed, for example, by impregnating water into a perfluorosulfonic acid thin film.

The unit cell 10 described above is hermetically stacked via the sealing material 11 (FIG. 4) wound along the outer edges of the separators 30 and 31 adjacent to each other, so that the separators 30 and 31 facing each other. The cooling layer S for circulating the cooling water described above is defined in the middle.
The sealing material 11 is made of a material that can be elastically deformed in accordance with the expansion / contraction deformation of the unit cell 10.
“Expansion / contraction deformation of the unit cell 10” refers to a dimensional change accompanying expansion and contraction of the unit cell 10 mainly in the stacking direction.

  In the present embodiment, the conductive deformation absorbing members 50 according to an example for absorbing expansion / contraction deformation of the unit cells 10 are provided in each cooling layer S partitioned for each adjacent unit cell 10, 10. The separators 30 and 31 are inserted in conductive contact.

  FIG. 6 is a diagram for explaining a cooling layer partitioned between unit cells according to an example adjacent to each other and a deformation absorbing member according to an example interposed between the cooling layers. 7A is a side view of a deformation absorbing member according to an example, FIG. 7B is a front view thereof, and FIG. 7C is a portion indicated by an encircling line I shown in FIG. FIG. In FIGS. 6, 7 </ b> A and 7 </ b> C, the direction orthogonal to the drawings is the flow direction of the cooling water.

  As shown in FIG. 7B, the deformation absorbing member 50 according to an example is made of metal formed in a rectangular shape in a front view, and a plurality of deformation absorbing members 50 parallel to the flow direction α of the cooling water in the cooling layer S described above. The elastic deformation portion 51 is integrally coupled between the long side edge portions 52 and 52 having a required width so as to be an area equivalent to the above-described power generation area.

  The elastic deformation portion 51 is in conductive contact with the separators 30 and 31 and elastically deforms according to the expansion / contraction deformation of the unit cell 10, and as shown in FIG. It has a shape.

  Adjacent elastic deformation portions 51 and 51 are formed at a predetermined pitch in a direction orthogonal to the flow direction α, and specifically, project at a constant pitch P2 in the direction orthogonal to the flow direction α. Yes.

  Furthermore, in this embodiment, the pitch P2 of the elastic deformation parts 51 and 51 is made larger than the pitch P1 of the rectification parts 30a and 31a. Thereby, it can prevent that the elastic deformation part 51 of the deformation | transformation absorption member 50 fits into the rectification | straightening parts 30a and 31a, and a required spring function is impaired.

  A part of the deformation absorbing member 50 described above is fixed to the separator 31. In the present embodiment, arbitrary one row of elastically deforming portions 51, 51 located on the outermost side portions are fixed to the separator 31 by welding.

Specifically, the top part of the elastic deformation part 51 is fixed to the opposing wall surface 31c of the rectification part 31a of the separator 31 by welding. In FIGS. 5 and 6, the fixed portion by welding is indicated by a symbol “M”.
By performing the fixing by welding, it is possible to suppress the sliding between the separator 31 and the deformation absorbing member 50 and to reduce the surface pressure fluctuation with respect to the displacement of the unit cell 10.

  In the present embodiment, an arbitrary row of elastic deformation portions 51 located on both sides, in other words, the fixing portions of the deformation absorbing member 50 and the separator 31 are positioned in the power generation area of the unit cell 10. Thereby, the improvement of the current collection property and electroconductivity of the deformation | transformation absorption member 50 and the separator 31 is realizable.

Further, the deformation absorbing member 50 and the separator 31 are welded and fixed to the deformation absorbing member 50 by line welding in which the rectifying portion 31a is linearly welded over the entire length of the rectifying portion 31a. You may fix by the stitch welding which welds.
Further, as a welding method, laser welding, electron beam welding, arc welding, plasma welding, resistance welding, friction welding, ultrasonic welding, diffusion welding, or a combination thereof can be performed. By these welding modes, the deformation absorbing member 50 and the separator 31 can be firmly fixed.

  In addition, in this embodiment, although the example which weld-fixed arbitrary one line of elastic deformation parts 51 and the rectification | straightening part 31a is demonstrated, arbitrary two or more rows of elastic deformation parts 51 and the rectification | straightening part 31a are welded. It may be fixed.

By the way, the pitch P2 of the elastic deformation part 51 can be set wide and narrow considering the circulation state of the cooling water, and the pitch may be changed regularly.
For example, the pitch is gradually narrowed from the long edge portions 52 and 52 to the central portion, and the pitch is gradually widened from the long edge portions 52 and 52 to the central portion.
Note that the deformation absorbing member 50 may be inserted into at least one of the cooling layers S in consideration of expansion / contraction deformation of the unit cell 10 without being inserted into all the cooling layers S.

As described above, the following effects can be obtained by inserting the deformation absorbing member 50 in the cooling layer S formed between the unit cells 10 and 10.
First, by disposing the deformation absorbing member 50 only in the power generation area, it is possible to prevent the cooling water from flowing unnecessarily outside the power generation area where much heat is generated. That is, if there is a lot of useless amount of cooling water, the temperature variation in the unit cell 10 increases, and it becomes easy to dry out during power generation.

In addition, the stacking structure parts of the fuel cell stack A, and particularly the membrane / electrode catalyst layer and the gas diffusion layer disposed in the power generation area, are easily damaged when the stacking load is excessively increased. The contact resistance between the membrane and the electrode catalyst layer, between the gas diffusion layer and the separator, and between the separator and the deformation absorbing member increases, and the resistance of the unit cell at the time of power generation increases and the performance decreases.
That is, as shown in the present embodiment, the load absorption in the power generation area important for the performance of the fuel cell stack A can be appropriately performed by interposing and arranging the deformation absorbing member 50 corresponding to the power generation area. .

  Further, since a part of the deformation absorbing member 50 is fixed to the separator 31, even when the deformation absorbing member 50 is compressed and tries to displace in the direction orthogonal to the stacking direction, the amount of displacement is limited by the fixing portion. The deformation absorbing member 50 can be kept at a position in the power generation area of the separator 31.

  Also, if the elasticity of the sealing material 11 is small, even when the separators 30 and 31 accompanying power generation are displaced, the deformation absorbing member 50 can be functioned without stretching the sealing material 11, while the elasticity of the sealing material 11 is large. If the surface rigidity of the separators 30 and 31 is low, the separators 30 and 31 can be bent and function as springs. Ideally, both the elasticity of the sealing material 11 and the surface elasticity of the separators 30 and 31 should be as small as possible.

Next, the case 20 will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the case 20 is formed in a rectangular parallelepiped shape having an internal volume that accommodates the cell stack B by fastening plates 21 and 21, reinforcing plates 22 and 22, and end plates 23 and 24.

  Current collector plates 60 and 61 are disposed between both end faces of the cell stack B and the end plates 23 and 24, and a spacer 62 is disposed between the one current collector plate 61 and the end plate 24. It is installed. “A” is a bolt.

  One end plate 23 has plate-side inflow holes 23 a, 23 b, approximately the same shape and size as the inflow holes 32 I, 33 I, 34 I and outflow holes 32 O, 33 O, 34 O of the unit cell 10. 23c and plate side outflow holes 23d, 23e, and 23f are formed.

  The current collecting plate 60 is formed in the same shape and size as the unit cell 10, and is substantially at positions facing the inflow holes 32I, 33I, 34I and the outflow holes 32O, 33O, 34O of the unit cell 10, respectively. Plate-side inflow holes 60a, 60b and 60c and plate-side outflow holes 60d, 60e and 60f having the same shape and size are formed.

The operation of the fuel cell stack A having the above configuration will be described with reference to FIGS.
When each unit cell 10 shown in FIG. 4 expands due to heat and the solid polymer electrolyte membrane 43 swells, the separators 30 and 31 facing each other in the adjacent unit cells 10 and 10 are separated by a distance L1 shown in FIG. To the interval L2 shown in FIG.

  When the interval between the separators 30 and 31 facing each other in the adjacent unit cells 10 and 10 is reduced, the deformation absorbing member 50 in the cooling layer S is elastically deformed as shown in FIG. To do.

On the other hand, when a displacement occurs in the direction in which the lamination load is removed due to heat shrinkage during operation, drying of the solid polymer electrolyte membrane 43, creep of components, etc., the deformation absorbing member 50 is lowered following the displacement. Prevent too much.
In other words, the “direction in which the stacking load is released” is synonymous with an increase in the distance between the separators 30 and 31, in other words, the height dimension of the cooling layer S.

  As a result, even if the conventional disc spring or gas diffusion layer displacement absorption is removed, the unit cell 10 during operation will absorb the increase / decrease displacement, the laminating load required for power generation (the upper limit is determined by the strength of the component, The lower limit side can be stably held (determined by the load necessary to ensure contact resistance).

Further, by inserting the deformation absorbing member 50 in the cooling layer S, the height of the circulating layer through which the hydrogen gas and air are circulated and the height of the cooling layer S can be optimally designed independently of each other.
Therefore, both the height (interval) of the flow layer and the cooling layer S can be reduced, and the size of the unit cell 10 in the stacking direction can be reduced, so that the fuel cell stack A itself can be downsized.

Furthermore, since the flow layer and the cooling layer S can be formed independently of each other, the flow direction of the cooling water and the flow direction of the air and hydrogen gas can be made different from each other, thus increasing the degree of freedom in design. be able to.
For example, the inflow direction of the cooling water and the rectifying units 30a and 31a are formed in a direction intersecting with the flow direction of air and hydrogen gas.

  Since the deformation absorbing member 50 and the separator 31 are fixed by welding, the electrical conductivity between the deformation absorbing member 50 and the separator 31 can be improved, and the surface pressure against the reduction of the sliding and the expansion / contraction displacement of the unit cell can be improved. The fluctuation can be reduced.

  Next, the deformation | transformation absorption member which concerns on a 1st modification is demonstrated with reference to FIG. FIG. 8 is a partially enlarged side view showing the deformation absorbing member according to the first modification and the unit cell according to an example in contact with the deformation absorbing member in a partially enlarged manner. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and description is abbreviate | omitted.

  The deformation absorbing member 70 according to the first modification is a metal member formed in a rectangular shape in a front view, and includes a plurality of elastic deformation portions 71 parallel to the flow direction α of the cooling water in the cooling layer S described above. , And integrally formed on a rectangular substrate (not shown).

  The elastic deformation portion 71 is in conductive contact with the separators 30 and 31 in FIG. 8 and elastically deforms according to the expansion / contraction deformation of the unit cell 10. In this embodiment, the elastic deformation portion 71 is in contact with the separators 30 and 31. It has a substantially sinusoidal cross-sectional shape in which a flat surface contact portion 71a is formed so as to increase the area.

  The adjacent elastic deformation portions 71, 71 are formed at a predetermined pitch in a direction orthogonal to the flow direction α, and project at a constant pitch in the direction orthogonal to the flow direction α as described above. It is the same.

  In this embodiment, the surface roughness of the contact surface on the separator 30, 31 side or the deformation absorbing member 70 side is increased. That is, when the surface roughness increases, the contact area increases, so the contact resistance decreases, and a certain point tends to increase again as a minimum value.

Further, by making the surface contact portion 71a flat (planar), it becomes surface contact, the contact area similarly increases and the contact resistance decreases, and therefore the power generation performance can be improved.
Furthermore, in this example, the surface contact portion 71a is fixed by welding to the rectifying portions 31a and 31a of the separator 31. Thereby, the two rectification | straightening parts 31a and 31a can be fixed to the one elastic deformation part 71, and the separator 31 and the deformation | transformation absorption member 70 can be fixed firmly. In addition, you may make it fix three or more rectification | straightening parts to the one elastic deformation part 71. FIG.

  Next, with reference to FIGS. 9 and 10, a fixing mode of a unit cell using the separator according to another example and the deformation absorbing member according to the example will be described. FIG. 9 is a partially enlarged side view illustrating a partially enlarged deformation absorbing member according to an example and a unit cell according to another example that contacts the deformation absorbing member, and FIG. 10 illustrates a separator and a deformation absorbing member according to another example. It is a cross-sectional perspective view which shows a fixed aspect and shows the structure in a simplified manner. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and description is abbreviate | omitted.

The unit cell 80 employs separators 81, 81 that do not form a rectification unit, in other words, have both surfaces formed flat.
In this case, the pitch P2 of the elastic deformation portion 51 of the deformation absorbing member 50 can be set regardless of the pitch of the rectifying portions 30a and 31a, and the separators 81 and 81 can be provided without providing a surface contact portion. Can be easily slid.
As shown in FIG. 10, among the elastically deformable portions 51, one row of elastically deformable portions 51, 51 located on both sides are fixed to the separator 81 by line welding.

  With reference to FIGS. 11-13, the fixed aspect of the unit cell using the separator which concerns on another example, and the deformation | transformation absorption member which concerns on an example is demonstrated. FIGS. 11-13 show the fixation aspect of the separator and deformation | transformation absorption member which concern on another example, and are the cross-sectional perspective views which show the structure simply. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and description is abbreviate | omitted.

  In the fixing mode shown in FIG. 11, among the elastically deformable portions 51, one row of elastically deformable portions 51, 51 located on both sides are fixed to the separators 81, 81 on both sides by line welding, respectively.

  The fixing mode shown in FIG. 12 is to fix the elastic deformation portions 51 and 51 located on the most opposite side of the elastic deformation portion 51 to the separators 81 and 81 on both sides by line welding, respectively, The plurality of elastically deformable portions 51 positioned at the position are welded and fixed to the one separator 81 by stitch welding discontinuously.

  In this case, the contact area of the fixed part between the deformation absorbing member 50 and the separator 81 is set to 10% or more of the contact area between the deformation absorbing member 50 and the separator 81. Thereby, the welding area of the deformation | transformation absorption member 50 and the separator 81 which are the minimum required for an electroconductive improvement can be limited, and welding cost can be suppressed. In addition, it is possible to ensure conductivity equal to or higher than the conductivity when the surface treatment is performed between the deformation absorbing member 50 and the separator 81 with a weld area of 10% or more of the contact area.

  In the fixing mode shown in FIG. 13, among the elastic deformation portions 51, one row of elastic deformation portions 51, 51 located on both sides is fixed to the separators 81, 81 on both sides by line welding, respectively, and at the center portion. The one elastic deformation part 51 and 51 located is fixed by the line welding which welds a contact part continuously.

  Also in this fixed form, the contact area of the fixed part between the deformation absorbing member 50 and the separator 81 is 10% or more of the contact area between the deformation absorbing member 50 and the separator 81. Thereby, the effect equivalent to what was demonstrated in FIG. 12 can be acquired.

  FIG. 14 is a partially enlarged side view showing the deformation absorbing member according to the second modification and the unit cell according to another example in contact with the deformation absorbing member partially enlarged. In addition, about the thing equivalent to what was demonstrated in the said FIG. 9, the code | symbol same as them is attached | subjected and description is abbreviate | omitted.

The deformation absorbing member 90 according to the second modification includes a plurality of elastic deformation portions 91 parallel to the flow direction α of the cooling water in the cooling layer S described above, on a substrate (not shown) formed in a rectangular shape in front view. It is formed by projecting together.
In the present embodiment, the elastic deformation portions 91 are formed at regular intervals along the flow direction α of the cooling water. In addition, the distribution direction α in FIG. 14 is a direction orthogonal to the screen.

The elastic deformation portion 91 is in conductive contact with the separator and elastically deforms according to the expansion / contraction deformation of the unit cell 80. In the present embodiment, the stress distribution portion 92 for dispersing the stress generated in the unit cell 80 is provided as a contact portion. It has a substantially sinusoidal cross-sectional shape formed on both sides of 91a.
The stress dispersion portion 92 has a bent portion 92a protruding upward and a bent portion 92b protruding downward, but may have three or more bent portions.

The adjacent elastic deformation portions 91, 91 are formed at a predetermined pitch in the direction orthogonal to the flow direction α, and project at a constant pitch in the direction orthogonal to the flow direction α as described above. It is the same.
Further, the contact portion 91a is welded to the separator 81 to perform stronger fixation.

  FIG. 15 is a partial perspective view of a deformation absorbing member according to a third modified example, and FIG. 16 is a front view of the deformation absorbing member according to the modified example. In addition, about the thing equivalent to what was demonstrated in each embodiment mentioned above, the code | symbol same as them is attached | subjected and description is abbreviate | omitted.

The deformation absorbing member 100 according to the third modification is provided with a plurality of elastic deformation portions 101 corresponding to the partial expansion / contraction deformation of the unit cell 10 described above.
In the present embodiment, an elastic band 103 in which a plurality of elastically deforming portions 101 are formed at a constant pitch P2 between the long edge portions 102, 102 having a constant width and orthogonal to the circulation direction α of the cooling water, They are constructed with a certain distance T from each other.
Furthermore, it is the same as that of the above-mentioned example that it can fix more firmly by welding the contact part 91a to the separator 81. FIG.

According to this configuration, variations in surface pressure can be made uniform, and a predetermined load and stroke can be secured as a spring displacement absorbing function.
The “stroke” is a dimension capable of being displaced in the stacking direction of the unit cells 10.
Further, by putting a constant interval T between each other, the spring reaction force for a certain stroke is reduced by the area (the number of spring peaks × the spring length) in the interval T. For this reason, the target lamination load can be shifted to a low region.

The present invention is not limited to the above-described embodiments, and the following modifications can be made.
In the above-described embodiment, a conductive deformation absorbing member that is in conductive contact with both separators defining the cooling layer and absorbs expansion / contraction deformation of the unit cell is interposed in the cooling layer, and Although the structure which fixed a part of deformation | transformation absorption member with the separator was demonstrated, it does not restrict to this.
That is, a conductive deformation absorbing member for absorbing expansion / contraction deformation of the unit cell is brought into conductive contact with the two separators, and at least a part of the deformation absorbing member is fixed to the two separators. It only has to be. That is, it is not restricted to the structure which inserted the deformation | transformation absorption member in the cooling layer.

-A deformation | transformation absorption member may be a leaf | plate spring, a wave spring, a coil spring, a grit spring, a disc spring, a fibrous thing, or those combinations.
In the above-described embodiment, the elastic deformation portion is described as an example having a substantially sinusoidal waveform, but may be formed in a rectangular wave, a triangular wave, a sawtooth shape, or the like.

The deformation absorbing member 90 according to the fourth embodiment shown in FIGS. 10 and 11 includes elastic bands 93 each having a plurality of elastic deformation portions 91 formed at a constant pitch so as to be orthogonal to the coolant flow direction α. Although an example in which the unit cell 10 is installed at a constant interval T has been described as an example, the elastically deformable portion 91 may be disposed in correspondence with partial expansion / contraction deformation of the unit cell 10.
For example, in the direction orthogonal to the flow direction α of the cooling water, the pitch of the elastic deformation portions 91 and 91 is increased from the long edge portions 92 and 92 toward the center portion, and the pitch is decreased.
Further, in the direction along the flow direction α of the cooling water, the pitch of the elastic deformation portions 91 and 91 is increased from both end portions toward the central portion, and the pitch is decreased.

  In the above-described embodiment, the example in which the deformation absorbing member is disposed in the power generation area where the combined body is disposed has been described. However, the deformation absorbing member may be disposed in a wide region including the power generation area.

  As described above in detail, in any case, each configuration described in each of the above embodiments is not limited to being applied only to each of the above embodiments, but the configuration described in one embodiment is replaced by another embodiment. It should be noted that it can be applied mutatis mutandis or applied, and can be arbitrarily combined.

10 Unit cells 30, 31 Separator 30a, 31a Rectifier 40 Assembly 41 Anode side electrode 42 Cathode side electrode 43 Electrolyte 50, 100 Deformation absorbing member 51, 91 Elastic deformation part 92 Stress dispersion part A Fuel cell stack S Cooling layer α Cooling Media distribution direction

Claims (7)

A plurality of unit cells in which an electrolyte is joined between an anode side electrode and a cathode side electrode are sandwiched between a pair of separators, and two types of power generation are provided on both electrodes of each unit cell. In a fuel cell stack that generates power by flowing gas separately from each other,
The unit cell is formed by laminating and laminating a cooling layer for circulating a cooling medium between the two separators facing each other.
Between the separators, a conductive deformation absorbing member for absorbing at least electrolyte expansion / contraction deformation of the unit cell is disposed,
In the region equivalent to the power generation area of the unit cell, the displacement absorbing member has a plurality of wave-shaped elastic deformation portions arranged in a direction intersecting with the flow direction of the cooling medium, and the top portions of the elastic deformation portions are connected to the separators. And at least a part of the displacement absorbing member is fixed to both separators,
Wherein the separators is a rectangular convex portion to each other the same shape and size, and having a plurality of rectifying portion formed at a constant pitch at the direction crossing the flow direction of the cooling medium, the cooling layer and the generator The gas distribution layer is divided and formed,
The pitch of the elastically deforming portion of the displacement absorbing member is larger than the pitch of the rectifying portion of the separator,
A fuel cell stack, wherein a top portion of an elastically deforming portion of the displacement absorbing member is fixed to a separator. While the deformation absorbing member is inserted in the cooling layer,
The deformation absorbing member has a plurality of elastic deformation portions arranged in a direction intersecting with the flow direction of the cooling medium, and among these elastic deformation portions, the elastic deformation portions located on both sides are respectively fixed to the separator. The fuel cell stack according to claim 1, wherein   3. The fuel cell stack according to claim 1, wherein a fixed portion between the deformation absorbing member and the separator is positioned in the power generation area of the unit cell.   The fuel according to any one of claims 1 to 3, wherein a contact area of a fixed portion between the deformation absorbing member and the separator is 10% or more of a contact area between the deformation absorbing member and the separator. Battery stack. While fixing the deformation absorbing member and the separator by welding,
The fuel cell stack according to any one of claims 1 to 4 , wherein the welding mode is line welding in which the contact portions are continuously welded.   The fuel cell stack according to claim 5, wherein the welding mode is stitch welding in which the contact portions are discontinuously welded.   The fuel according to claim 5 or 6, wherein the welding mode is laser welding, electron beam welding, arc welding, plasma welding, resistance welding, friction welding, ultrasonic welding, diffusion welding, or a combination thereof. Battery stack.

Images