JP5305893B2 - External manifold fuel cell - Google Patents

Description

  The present invention relates to an external manifold type fuel cell in which a manifold is disposed outside a stacked body in which a plurality of unit cells are stacked.

  A fuel cell laminate using a solid polymer electrolyte membrane having proton conductivity as an electrolyte has gas flow passages on both sides of a membrane electrode assembly (MEA) in which the electrolyte membrane is sandwiched between a fuel electrode and an oxidant electrode. A single cell battery is configured by arranging the provided electrically conductive separator, and both ends of the laminate in which a plurality of single cell batteries are stacked are held by end plates, and a plurality of studs are passed through holes penetrating both end plates, The laminate is tightened via a spring.

  For such a fuel cell stack, in the external manifold system, the gas flow path provided in the separator is extended to the end of the separator and opened to the side of the stack, and a separate external manifold is provided on the side to provide gas. Is distributed. In this external manifold method, since the separator does not include a manifold, the size is equivalent to the effective area of the membrane electrode assembly, and the separator can be made compact, which is advantageous for cost reduction. In addition, an insulating and inexpensive plastic can be used for the external manifold, and the cost increase can be minimized. The volume of the manifold can also be set without being restricted by the size of the separator, and gas and cooling water can be evenly distributed by the gas / cooling water flow passage of each single cell battery constituting the laminate.

  In the external manifold system, it is necessary to seal liquid (cooling water) and gas (fuel gas, oxidant gas) between the manifold and the side surface of the laminate. As a seal, a method of sealing by applying a low-viscosity adhesive (see, for example, Patent Document 1), a method of sealing by holding a rubber sponge, a method of sealing by inserting an O-ring, and the like are known. ing.

JP2008-218087

  However, the method of sealing with an adhesive and the method of sealing with a rubber sponge have a problem in that durability is low due to deterioration of the adhesive force over time and sag due to bubbles being removed from the sponge. Further, in the method of inserting and sealing the O-ring, there is a problem in that the crushing margin of the O-ring to be used is small and the bending of the manifold and the unevenness on the side surface of the laminated body cannot be absorbed, resulting in low sealing performance.

  That is, the manifold is fastened and fixed at several places to the laminate. On the other hand, the manifold is molded of resin, and the thickness of the resin is relatively thin although considering its strength and safety. Therefore, due to the influence of the internal pressure of the manifold and the difference in tightening pressure, the resin manifold is slightly deformed, and there is a gap between the edge of the manifold and the side of the laminate between the place close to the fixed part and the place away from it. Dimensional differences are inevitable.

  In the prior art, the gap size difference is filled by an adhesive that seals the gap between the edge of the manifold and the side surface of the laminate or the elastic deformation force of the O-ring. However, in the case of an adhesive, there is a problem of aging deterioration as described above, which is not a preferable means. On the other hand, in the case of an O-ring, the thickness of the manifold is small, so that the diameter that can be used for sealing the edge of the manifold and the side surface of the fuel cell is limited. Such a small-diameter O-ring has a small crushing allowance (deformable dimension), and cannot absorb the dimensional difference in the gap between the edge of the manifold and the side surface of the laminate.

  The present invention has been made in order to solve the above-described problems, and has a long shrinkage allowance, can absorb dimensional changes such as manifold deflection and unevenness on the side surface of the laminate, and has an excellent sealing structure. An object is to provide a manifold type fuel cell.

In order to achieve the above object, an external manifold type fuel cell according to the present invention includes a fuel cell stack, an external manifold disposed around the fuel cell stack, a junction between the fuel cell stack and the external manifold, or the external manifold. In an external manifold type fuel cell provided with a sealing material that seals a joint portion between each other, the sealing material is disposed in a groove provided on a joint surface of either the external manifold or the fuel cell stack, The seal material is formed of a string-like elastic material that is deformed by a load applied to the external manifold, and the seal material has a width dimension that fits within the thickness of the external manifold, and a dimension in the load direction that is larger than the width. has a vertically long cross section having, with the sealing member, the space is provided on at least a portion between the inner peripheral surface of the groove, Shrinkage allowance of the load direction of the sealing material, the said fuel cell stack definitive external manifold upon fixed to the a size enough to absorb the gap error generated between the external manifolds to the fuel cell stack Features.

Incidentally, the sealing member, or a substantially T-shaped or dumbbell-shaped cross-section, in addition to the seal structure of the fuel cell stack and the external manifold, also be sealed by a sealant of similar structure to each other outside manifold, the present invention It is one mode.

  According to the present invention having the above-described configuration, it has a long shrinkage, can absorb dimensional changes such as manifold deflection and unevenness on the side surface of the laminate, and has a structure of a sealing material that is excellent in durability. An excellent and highly reliable external manifold fuel cell can be provided.

  Embodiments of an external manifold type fuel cell according to the present invention will be described below with reference to the drawings. Here, in each embodiment, the same code | symbol is attached | subjected to the same or similar component, and the overlapping description is abbreviate | omitted.

[First Embodiment]
The configuration of the first embodiment will be described with reference to FIG. FIG. 1 is a sectional view showing a fuel cell according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the sealing material portion.

  In FIG. 1, reference numeral 1 denotes an external manifold constituting the fuel cell of the present invention. The manifold 1 is provided with an oxidant gas inlet / outlet port 1a, a fuel gas inlet / outlet port 1b, and a cooling water inlet / outlet port 1c. Supply cooling water at a flow rate to cool the heat generated by the reaction.

  Reference numeral 2 denotes a sealing material disposed at the joint between the opening of the manifold 1 and the laminate 3. The sealing material 2 is a string-like member that is deformed by a load applied to the manifold 1, and compressively deforms by a load applied to the manifold 1 to seal the manifold 1 and the laminate 3. This sealing material 2 is manufactured by compression molding or injection molding a rubber material such as silicon, fluorine, EPDM, etc. with a mold.

  In the present embodiment, the sealing material 2 has a substantially T-shaped cross section in which a projection having a rectangular cross section is provided on a flat base fixed to the manifold 1 with an adhesive. That is, the width of the base is set to a dimension equal to or smaller than the thickness of the manifold 1, the dimension in the load direction from the manifold 1 is set to be larger than the width of the base, and the entire sealing material 2 has a substantially long and substantially T-shaped cross-sectional shape. The shrinkage allowance in the load direction of the sealing material 2 is a size that absorbs a gap error generated between the laminate 3 and the manifold 1 when the laminate 3 and the manifold 1 are joined. That is, since the shrinkage allowance of the sealing material 2 is determined by the ratio of the lateral width and height of the protrusion, in order to secure the shrinkage allowance in the load direction, the width dimension of the base and the dimension in the load direction of the rectangular protrusion portion. A predetermined dimensional difference is set in (height dimension).

  The operation of the first embodiment having the above configuration will be described. FIG. 2A is a diagram showing a state before a load is applied to the manifold 1. In this state, since no load is applied to the sealing material 2, the protruding portion of the sealing material 2 remains rectangular. FIG. 2B is a diagram illustrating a state in which a load is applied to the manifold 1. In this state, a load is applied to the sealing material 2, and the protrusions are shrunk by the load, a sealing pressure is applied to the contact surfaces of the manifold 1 and the laminate 3 and the sealing material 2, and the contact surfaces of the manifold 1 and the laminate 3 and the sealing material 2. Is in close contact.

  In the first embodiment as described above, the manifold 1 and the laminated body 3 can be hermetically sealed by bringing the contact surfaces of the manifold 1 and the laminated body 3 and the sealing material 2 into close contact. By making the shape of the sealing material 2 into a flat base and a protrusion having a rectangular cross-sectional shape, it is advantageous in terms of the shrinkage allowance over the shape of only the flat base, and it is possible to secure a shrinkage allowance of 1 mm or more. it can. Thereby, even when there is a dimensional difference in the gap between the manifold 1 and the laminated body 3 due to the flatness of the side surface of the laminated body 3 and the distortion due to the load by the manifold 1, it can be reliably absorbed.

  In addition, since the base portion of the sealing material 2 is fixed to the manifold 1 by an adhesive, when the load is applied to the sealing material 2 from a direction other than the loading direction of the manifold 1, the sealing material 2 is shifted laterally. Can be prevented. It is also possible to prevent the sealing material 2 from shifting laterally by using friction between the manifold 1 and the laminate 3 and the sealing material 2 due to a load from the manifold 1 without using an adhesive. Furthermore, since the sealing material 2 can be manufactured with a mold, post-processing is unnecessary, and the sealing material 2 can be manufactured in large quantities and at low cost.

[Second Embodiment]
The configuration of the second embodiment will be described with reference to FIG. FIG. 3 is an enlarged cross-sectional view of a sealing material portion showing a second embodiment according to the present invention. 2nd Embodiment changes the shape of the sealing material 2 of 1st Embodiment.

  In the present embodiment, the sealing material 2 has a substantially dumbbell shape in which a recessed portion having a rectangular cross section is provided in a central portion sandwiched between upper and lower flat bases. That is, the width dimension of the upper and lower bases is a dimension equal to or less than the thickness of the manifold 1, the dimension (height dimension) in the load direction from the manifold 1 is larger than the width dimension of the base, and the entire sealing material 2 is vertically long. The cross-sectional shape is substantially dumbbell. The dimension in the load direction is such that the shrinkage allowance in the load direction of the sealing material 2 absorbs a gap error generated between the laminate 3 and the manifold 1 when the laminate 3 and the manifold 1 are joined. Note that at least one of the manifold 1 and the laminate 3 is fixed to the top and bottom with an adhesive.

  The operation of the first embodiment having the above configuration will be described. FIG. 3A is a diagram illustrating a state before a load is applied to the manifold 1. In this state, since no load is applied to the sealing material 2, the protruding portion of the sealing material 2 remains rectangular. FIG. 3B is a diagram showing a state in which a load is applied to the manifold 1. In this state, a load is applied to the sealing material 2, and the central dent portion is shrunk by the load, a sealing pressure is applied to the contact surface between the manifold 1 and the laminate 3 and the sealing material 2, and the manifold 1, the laminate 3 and the sealing material 2 are applied. The contact surface is closely attached.

  As an effect of the second embodiment as described above, in addition to the effect of the first embodiment, the seal member 2 is formed in a substantially dumbbell shape so that the manifold 1 and the laminate 3 can be sealed. A wide contact area with the material 2 can be taken. Therefore, when a load is applied to the sealing material 2 from a direction other than the load direction of the manifold 1 (for example, the lateral direction), the sealing material 2 is difficult to be displaced.

[Third Embodiment]
The configuration of the third embodiment will be described with reference to FIG. FIG. 4 is an enlarged cross-sectional view of a sealing material portion showing a third embodiment according to the present invention. In the third embodiment, a groove 4 for inserting the sealing material 2 is provided at a joint portion with the laminate 3. This groove 4 is a groove perpendicular to the contact surface of the manifold 1 with the laminate 3 and is provided over the entire periphery of the joint portion of the manifold 1 with the laminate 3.

  The shape of the sealing material 2 is a substantially T-shaped cross section in which a flat base is provided with a protrusion having a rectangular cross section. The width dimension of the T-shaped base is the same as the lateral width of the groove 4, and the width dimension of the rectangular protrusion is smaller than the width of the groove 4. In addition, the dimension (height dimension) in the load direction of the sealing material 2 is a dimension in which the total height of the base and the rectangular portion is larger than the depth of the groove 4. That is, when the sealing material 2 is disposed in the groove 4, a part of the rectangular portion of the sealing material 2 protrudes from the groove 4. The protruding portion is compressed when the laminated body 3 and the manifold 1 are joined, and has a size that absorbs a gap error generated between the laminated body 3 and the manifold 1. Further, since the contact between the manifold 1 and the laminated body 3 is not hindered, the size of the protruding portion is set within the contraction allowance of the seal material 2 in the load direction.

  The operation of the third embodiment having the above configuration will be described. FIG. 4A is a diagram illustrating a state before a load is applied to the manifold 1. Since no load is applied to the sealing material 2, the protruding portion of the sealing material 2 remains rectangular, and neither the manifold 1 nor the laminate 3 is in contact. When a load is applied to the manifold 1 from this state, a load is applied to the sealing material 2 and the protrusions are shrunk by the load, and a sealing pressure is applied to the contact surface between the manifold 1 and the laminated body 3 and the sealing material 2. And the contact surface of the sealing material 2 are in close contact with each other.

  FIG. 4B is a diagram showing a state in which a load is further applied to the manifold 1 from the state of FIG. In this state, due to the load from the manifold 1, the seal material 2 contracts by the difference between the depth of the groove 4 and the height of the seal material 2, and the manifold 1 and the laminate 3 come into contact with each other. In this case, if there is a gap between the manifold 1 and the laminated body 3 other than the place where the manifold 3 is in contact, the degree of compression of the sealing material 2 at that portion is reduced, but the shrinkage allowance of the sealing material 2 is reduced. Is a dimension that absorbs the gap error, and the gap is also sealed with the sealing material 2.

  As described above, the effect of the third embodiment is that the load applied to the manifold 1 can be uniformly distributed in addition to the effects of the respective embodiments. That is, the manifold 1 comes into contact with the laminated body 3 by setting the dimension of the portion of the sealing material 2 protruding from the groove 4 within the contraction allowance of the sealing material 2 in the load direction. As a result, even if a large load (clamping force) is applied to the manifold 1, it is not further applied to the sealing material 2. Therefore, it is not necessary to keep the load on the manifold 1 constant in consideration of the deformation amount of the sealing material 2, and the spring and the disc spring that keep the load constant can be eliminated, and the tightening portion can be made a simple and inexpensive structure. . Further, by providing the groove 4 in the manifold 1, it is possible to combine with the existing laminated body 3 only by changing the design of the manifold 1.

  Furthermore, even when the base portion of the sealing material 2 and the manifold 1 are not fixed with an adhesive, since the sealing material 2 is fixed by the groove 4, it is possible to prevent the sealing material 2 from shifting laterally. Furthermore, since most of the sealing material 2 is not exposed by disposing the sealing material 2 in the groove 4, it is possible to prevent the sealing material 2 from being deteriorated or damaged.

[Fourth Embodiment]
The configuration of the fourth embodiment will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional view of a sealing material portion showing a fourth embodiment according to the present invention. In the fourth embodiment, the groove 4 of the third embodiment is provided in the laminate 3. This groove 4 is a groove perpendicular to the contact surface of the laminate 3 with the manifold 1, and is provided over the entire circumference of the joint portion of the laminate 3 with the manifold 1.

  By disposing the sealing material 2 having a T-shaped cross section in the groove 4, it is possible to prevent the sealing material 2 from shifting in the lateral direction when a load is applied to the sealing material 2 from a direction other than the load direction. Moreover, since the part which the sealing material 2 exposes can be decreased, the failure | damage and deterioration of the sealing material 2 can be prevented.

  In the fourth embodiment, as shown in FIGS. 5A and 5B, the joint surface between the manifold 1 and the laminate 3 is sealed by the sealing material 2. In particular, in addition to the effects of the above-described embodiments, by providing the groove 4 in the laminated body 3 portion, the durability of the portion where the groove 4 is provided can be enhanced. That is, by providing the groove 4 in the laminated body 3 that can secure a sufficient space on both sides of the groove rather than in the plastic manifold 1 having a small thickness, the durability of the joint portion between the manifold 1 and the laminated body 3 can be improved. Get higher.

  Further, the manifold 1 used in the present embodiment can be provided with the groove 4 as in the third embodiment. By providing the groove 4 in each of the laminated body 3 and the manifold 1, the sealing material 2 is not displaced at the time of assembly, so that the sealing material 2 can be easily disposed between the manifold 1 and the laminated body 3.

[Fifth Embodiment]
The configuration of the fifth embodiment will be described with reference to FIG. FIG. 6 is an enlarged cross-sectional view of a sealing material portion showing a fifth embodiment according to the present invention. 5th Embodiment changes the shape of the sealing material 2 of 3rd Embodiment.

  In this embodiment, the shape of the sealing material 2 is a substantially cross-shaped cross section in which protrusions having a rectangular cross section are provided above and below a flat base. The width of the base of the substantially cross-shaped sealing material 2 is the same as the width of the groove 4, and the width of the upper and lower rectangular protrusions is smaller than that of the groove 4. The dimension in the load direction of the sealing material 2 is the same as that in the third embodiment.

  In the fifth embodiment having the above-described configuration, as shown in FIGS. 6A and 6B, when a load is applied to the manifold 1 and the manifold 1 and the laminated body 3 are in contact with each other, the seal from the manifold 1 is applied. The manifold 2 and the laminated body 3 are sealed in a state in which the material 2 is compressed and the upper and lower protrusions spread laterally.

  As described above, the effect of the fifth embodiment includes the ratio of the height to the lateral width of each protrusion by making the shape of the sealing material 2 into a substantially cross-sectional shape in addition to the effects of the above embodiments. Can be lowered. That is, when the height of the protrusion is constant with respect to the height of the base, the height of the protrusion is halved in the case of two protrusions compared to the case of one protrusion. it can. Thereby, it is possible to prevent the rectangular portion from being bent by the load from the manifold 1. Further, by making the width dimension of the groove 4 equal to the width dimension of the flat plate-like base portion of the sealing material 2, the sealing material 2 can be reliably fixed.

[Sixth Embodiment]
The configuration of the sixth embodiment will be described with reference to FIG. FIG. 7 is an enlarged cross-sectional view of a sealing material portion showing a sixth embodiment according to the present invention. In the sixth embodiment, in the fuel cell in which the joint portion between the manifold 1 and the laminated body 3 in each of the embodiments is sealed with the sealing material 2, the joint portion between the manifold 1 and the second manifold 6 is also described above. The second sealing material 7 is added.

  In the present embodiment, the contact surface between the second manifold 6 and the second seal material 7 and the contact surface between the second seal material 7 and the second manifold 6 are brought into close contact with each other, and gas and cooling water are supplied to the laminate 3. The surface of the manifold 1 can be sealed instead of the surface. Further, since the amount of contraction of the manifold 7 can be secured to 1 mm or more, the flatness of the manifold 1 and the distortion due to the load by the second manifold 6 can be absorbed. This eliminates the need to design the size of the second manifold 6 in accordance with the size of the stacked body 3, thereby increasing the degree of freedom in designing the second manifold 6. Moreover, even if the laminated body 3 is not a rectangular parallelepiped, there is an advantage that the same member as the second manifold 6 and the manifold 1 is used, and it is not necessary to redesign the manifold when the laminated body 3 is changed in design. Have.

[Other Embodiments]
The embodiments described above are merely examples, and the present invention is not limited to these. Moreover, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim.

  In each embodiment, the shape of the sealing material 2 or the sealing material 2 is a substantially T-shaped cross-section or a substantially cross-shaped cross-section, but the same effect can be obtained if the shape is triangular or semicircular. For example, even in a sealing material having an elliptical cross section that is long in the vertical direction as shown in FIG. 8, the center part contacts the left and right groove side surfaces after loading and exhibits the same effect as the flat plate part of the base, and the upper and lower semicircular shapes It is sealed at the part and exhibits the same effect. The sealing material 2 having such a shape has an advantage that the work for arranging the sealing material 2 in the groove 4 can be easily performed. Furthermore, since it is a simple shape, it is easy to process and can be manufactured in large quantities and at low cost.

1 is a cross-sectional view of a fuel cell according to a first embodiment of the present invention. The expanded sectional view of the seal part in a 1st embodiment of the present invention. The expanded sectional view of the seal part in a 2nd embodiment of the present invention. The expanded sectional view of the seal part in a 3rd embodiment of the present invention. The expanded sectional view of the seal part in a 4th embodiment of the present invention. The expanded sectional view of the seal part in a 5th embodiment of the present invention. The expanded sectional view of the seal part in a 6th embodiment of the present invention. The expanded sectional view of the seal part in other embodiments of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Manifold 2 ... Seal material 3 ... Laminated body 4 ... Seal material groove | channel 6 ... 2nd manifold 7 ... 2nd seal material

Claims (6)

An external manifold type fuel cell comprising: a fuel cell stack; an external manifold disposed around the fuel cell stack; and a sealing material for sealing a joint between the fuel cell stack and the external manifold or a joint between the external manifolds In
The sealing material is disposed in a groove provided on a joint surface of either the external manifold or the fuel cell stack,
The sealing material is constituted by a string-like elastic material that is deformed by a load applied to the external manifold,
This sealing material has a vertically long cross-sectional shape having a width dimension that fits within the wall thickness of the external manifold, and a dimension in the load direction that is larger than the width,
A space is provided in at least a part between the sealing material and the inner peripheral surface of the groove,
That this contraction potential of the load direction of the seal member is sized enough to absorb the gap error generated between the fuel cell stack definitive upon fixing the external manifold the fuel cell stack and the external manifold Features an external manifold fuel cell. The sealing material, outer manifold type fuel cell according to claim 1, characterized in that it comprises a substantially T-shaped cross section having a rectangular projection on a flat plate-like base. The sealing material, outer manifold type fuel cell according to claim 1, characterized in that it has a dumbbell-like cross-sectional shape having a recess held between the upper and lower flat plate-like base central portion. 2. The external manifold type fuel cell according to claim 1, wherein the sealing material has a cross-shaped cross-sectional shape in which protrusions having a rectangular cross section are provided above and below a flat base. The external manifold fuel cell according to claim 1, wherein the sealing material has an elliptical cross-sectional shape that is long in the vertical direction. A second manifold disposed at a right angle to the external manifold on a side surface different from the position of the external manifold in the fuel cell stack;
The second manifold, wherein the width of the fuel cell stack opening wider than the width of the fuel cell stack, the opening edge is characterized in that abuts against the outer side of the outer manifold Item 6. The external manifold type fuel cell according to any one of Items 1 to 5 .

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