JP5227015B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack.

  In a fuel cell stack having a laminate in which a plurality of power generators each having electrodes disposed on both sides of an electrolyte membrane are stacked with a separator interposed therebetween, conventionally, in order to prevent leakage of fuel gas or oxidant gas, In order to reduce the contact resistance, a fastening load is applied in the stacking direction of the fuel cell stack. For example, there is a method in which end plates are provided at both ends of a laminate, and end plates at both ends are fastened via a tension plate to apply a fastening load in the stacking direction of the laminate.

  Incidentally, stack components such as a power generator and a separator constituting the fuel cell stack expand due to heat generated during power generation of the fuel cell stack. On the other hand, the tension plate hardly expands because heat during power generation is hardly transmitted. That is, even during operation of the fuel cell stack, the tension plate does not expand (expand) in the stacking direction of the fuel cell stack, so that each stack component expands with both ends of the fuel cell stack fixed. In some cases, a load (hereinafter, also referred to as “surface pressure”) applied in the stacking direction of the stacked body increases.

  In addition, with the operation / stop of the fuel cell stack, the respective thickness may decrease due to the creep of the electrolyte membrane and the electrode. In such a case, the load applied in the stacking direction of the stacked body is reduced, and the contact resistance of the electrode may increase or the sealing performance may decrease.

  Therefore, a spring module in which a plurality of coil springs are sandwiched between two plates is disposed between the laminated body and the end plate, and the spring module expands and contracts in response to expansion and contraction in the stacking direction of the laminated body. A technique for adjusting the surface pressure applied in the stacking direction of the stack has been proposed (see, for example, Patent Document 1).

JP 2004-288618 A

  However, in the above-described laminated body, for example, due to an electrode manufacturing error, a thickness non-uniformity may occur in the surface direction of the electrode. Similarly, the electrolyte membrane and the separator may each have non-uniform thickness in the surface direction. By stacking components having such a non-uniform thickness, the stacked surface at one end of the stacked body may be inclined with respect to the stacked surface at the other end.

  Also, during power generation, in each component of the laminated body such as electrodes, electrolyte membranes, separators, etc., if a biased heat distribution occurs in the respective surface direction, it does not expand uniformly in the laminating direction. The surface may be inclined with respect to the laminated surface at the other end.

  In such a case, in the above-described spring module, the two plates may be displaced in the direction of the stacking surface. As a result, the spring does not expand and contract in parallel with the stacking direction, but tilts and expands and contracts with respect to the stacking direction, so that a desired load may not be obtained in the stacking direction with respect to the stacked body. In addition, an unnecessary load may be applied in a direction perpendicular to the stacking direction.

  Such a problem is not limited to the case of using a coil spring, and is common to members that adjust the surface pressure applied in the stacking direction of the stacked body using various elastic bodies such as a disc spring, rubber, sponge, and the like. It is a problem. This invention is made | formed in view of such a subject, and it aims at providing the technique which adjusts the surface pressure concerning a laminated body.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
In one embodiment of the present invention, a power generation body in which electrodes are disposed on both surfaces of an electrolyte membrane is disposed by stacking a plurality of layers, and disposed at an end portion of the multilayer body, and can be expanded and contracted in the stacking direction of the multilayer body. A stretchable member comprising: a first plate; a second plate disposed opposite to the first plate; the first plate; An elastic body disposed between the second plate and a shaft protruding from the second plate, and the first plate has a through-hole through which the shaft is inserted. The diameter of the through hole is larger than the diameter of the shaft, and the shaft can move obliquely with respect to the through hole. According to the fuel cell stack of this embodiment, since the shaft protruding from the second plate is inserted into the through hole provided in the first plate of the elastic member, the first plate and the second plate that face each other. It is possible to prevent the position in the surface direction from shifting or the angle at which the plates face each other from being greatly inclined.

Application Example 1 A power generating body in which electrodes are disposed on both surfaces of an electrolyte membrane is a stacked body in which a plurality of layers are stacked, and an expansion / contraction that is disposed at an end of the stacked body and can expand and contract in the stacking direction of the stacked body. A fuel cell stack comprising members,
The elastic member is
A first plate;
A second plate disposed opposite the first plate;
An elastic body disposed between the first plate and the second plate;
A shaft protruding from the second plate;
With
The first plate includes
A fuel cell stack, wherein a through hole through which the shaft is inserted is formed.

  According to the fuel cell stack of the present invention, since the shaft protruding from the second plate is inserted into the through-hole provided in the first plate of the elastic member, the first plate and the second plate that face each other. It is possible to prevent the position in the surface direction from shifting or the angle at which the plates face each other from being greatly inclined.

  In addition, the elastic body should just be a member which has elasticity. For example, various springs such as a coil spring, a disc spring, and a leaf spring, and various elastic bodies such as rubber and sponge can be used.

[Application Example 2] In the fuel cell stack according to Application Example 1,
The fuel cell stack, wherein the second plate is located closer to the stacked body than the first plate.

[Application Example 3] In the fuel cell stack according to Application Example 1 or 2,
The elastic member is
Further comprising a through-hole covering member covering the inner periphery of the through-hole,
The fuel cell stack, wherein a friction coefficient of the through hole covering member with respect to the shaft is smaller than a friction coefficient of the through hole of the first plate with respect to the shaft.

  In this case, the frictional force generated by contact with the shaft is smaller than when no through-hole covering member is provided, so that it is possible to suppress an extra load from being applied to the laminate due to the frictional force. . Moreover, when a shaft and the through-hole of a 1st plate contact directly, the contact part can be scraped off and it can suppress that an expansion-contraction member deteriorates.

  Note that the friction coefficient may be either a dynamic friction coefficient or a static friction coefficient, or may be defined by both.

[Application Example 4] In the fuel cell stack according to Application Example 3,
The fuel cell stack, wherein the through hole covering member is made of resin.

Application Example 5 In the fuel cell stack according to any one of Application Examples 1 to 4,
The elastic member is
A fastener for fastening the shaft so as not to come out of the through hole;
The first plate is
The fuel cell stack further comprising a recess communicating with the through hole and receiving at least a part of the fastener.

  As the fastener, for example, a bolt, a screw, a pin or the like can be used. Since the shaft does not come out of the through hole by the fastener, the elastic member is integrated. And since the 1st plate is provided with the recessed part into which at least one part of a fastener enters, the amount of protrusions from which a fastener protrudes rather than the 1st plate can be reduced.

Application Example 6 In the fuel cell stack according to any one of Application Examples 1 to 5,
The elastic body is
A coil spring,
The first and second plates include
A concave spring hole is formed that opens on each facing surface.
The spring hole is
A fuel cell stack, wherein the diameter of the fuel cell stack increases from the bottom surface toward the opening.

  Since the diameter of the spring hole is increased from the bottom surface toward the opening, for example, when the coil spring expands and contracts obliquely with respect to the first plate or the second plate, It becomes difficult to hit the surface. For this reason, the coil spring can be prevented from being worn by contacting the spring hole.

Application Example 7 In the fuel cell stack according to any one of Application Examples 1 to 5,
The elastic body is
A coil spring,
The first and second plates include
A concave spring hole is formed in each facing surface, and a concave spring hole is formed.
A spring hole covering member that covers the inner periphery of the spring hole;
A fuel cell stack, wherein a coefficient of friction of the spring hole covering member with respect to the coil spring is smaller than a coefficient of friction of the spring hole provided in the first and second plates with respect to the coil spring.

  In this case, for example, when the coil spring expands and contracts obliquely with respect to the first plate or the second plate, even if the coil spring and the spring hole covering member come into contact, the coil spring and the spring hole Since the frictional force generated in the coil spring is smaller than in the case of direct contact, it is possible to suppress the coil spring from being worn.

[Application Example 8] In the fuel cell stack according to Application Example 7,
The fuel cell stack, wherein the spring hole covering member is made of resin.

  The present invention can be realized in various forms. For example, the present invention can be realized in the form of a fuel cell stack, a fuel cell system including the fuel cell stack, a moving body equipped with the fuel cell system, and the like. Can do.

A. First embodiment:
A1. Example configuration:
FIG. 1 is an explanatory diagram showing the configuration of a fuel cell stack 100A as a first embodiment of the present invention. The fuel cell stack 100A is a solid polymer type fuel cell that generates power using hydrogen and air. As shown in FIG. 1, an end plate 11, an insulating plate 12, a current collecting plate 13, and a laminate are provided from one end. 14, a current collector plate 15, an insulating plate 16, a spring member 30, a pressure plate 17, and an end plate 18 are stacked in this order.

  Then, the tension plate 19 is fastened to the end plates 11 and 18 with bolts 20 and the pressure plate 17 is pressed with a predetermined pressing force with the adjusting screw 21, whereby the fuel cell stack 100 </ b> A is attached to the stacked body 14. It is held in a state where a predetermined pressing force is applied in the stacking direction (X direction in the figure). A through hole into which the adjustment screw 21 is inserted is provided at the approximate center of the end plate 18, and a screw thread is formed on the inner periphery thereof. A thread is also formed on the outer periphery of the adjustment screw 21, and the thread of the adjustment screw 21 is screwed to a thread formed on the inner periphery of the through hole of the end plate 18, thereby adjusting the screw 21. Is fixed, and the pressure plate 17 is pressed with a predetermined pressing force. Each of the current collecting plates 13 and 15 is provided with an output terminal (not shown) so that the power generated by the fuel cell stack 100A can be output.

  As shown in the figure, the laminated body 14 is configured by alternately laminating MEA (Membrane-Electrode Assembly) 14m and separators 14s. The MEA 14m includes an electrolyte membrane made of an ion exchange membrane, an anode and a cathode respectively disposed on both surfaces of the electrolyte membrane, and a diffusion layer laminated on the anode and the cathode. The separator 14s is formed with a gas flow path for supplying hydrogen as a fuel gas to the anode and air as an oxidant gas to the cathode, and a cooling water flow path for flowing cooling water for cooling the fuel cell. In this embodiment, the MEA 14m corresponds to the power generator in the claims, and the spring member 30 corresponds to the elastic member in the claims.

A1-1. Configuration of the spring member 30:
FIG. 2 is a perspective view showing the overall configuration of the spring member 30, and FIG. 3 is an explanatory view schematically showing an AA cut surface in FIG. As shown in FIGS. 2 and 3, the spring member 30 mainly includes an upper plate 31, a lower plate 32, a plurality of coil springs 33, a shaft 34, a washer 37, and a bolt 38.

  As shown in the drawing, the upper plate 31 is an aluminum flat plate having a substantially rectangular shape similar to the laminated surface shape of the laminated body 14. The upper plate 31 is formed with a total of six through holes 35 through which the shaft 34 is inserted, near four corners and near the center. The inner periphery of the through hole 35 is covered with a covering member 36 made of POM (polyacetal). The through hole 35 forms a substantially cylindrical cavity, and its diameter is slightly larger than the diameter of the cross section of the shaft 34.

  The covering member 36 has a substantially ring shape, and claws 36n projecting outward are formed at both ends thereof. The covering member 36 is pushed into the through hole 35 of the upper plate 31 to be shown in FIG. As described above, the claw 36n is caught by the upper plate 31 and covers the inner periphery of the through hole 35.

  In addition, a plurality of spring holes 39u into which one end of the coil spring 33 is fitted are formed on the facing surface of the upper plate 31 that faces the lower plate 32.

  The lower plate 32 is an aluminum flat plate having a substantially rectangular shape similar to the upper plate 31. The lower plate 32 is provided with the same number of spring holes 39l as the above-described 39u on the opposite surface of the lower plate 32 that faces the upper plate 31 to which the other end of the coil spring 33 is fitted.

  The coil spring 33 is made of spring steel. Examples of the spring steel include silicon manganese steel (SUP6, SUP7), manganese chrome steel (SUP9, SUP9A), chrome vanadium steel (SUP10), manganese chrome boron steel (SUP11A) specified in JIS G 4801. ), Silicon chrome steel (SUP12), and chrome molybdenum steel (SUP13).

  The shaft 34 is an iron hollow cylinder plated with nickel-phosphorus alloy, and protrudes from a total of six locations near the four corners and near the center of the lower plate 32. When the spring member 30 is completed, the shaft 34 is inserted into the through hole 35. A screw thread is formed on the inner periphery of the shaft 34 and also functions as a nut.

  As shown in FIG. 3, one end of the coil spring 33 is fitted into the spring hole 391 of the lower plate 32 and the other end of the coil spring 33 is fitted into the spring hole 39 u of the upper plate 31. Then, the upper plate 31 and the lower plate 32 are fastened via the shaft 34 by screwing the bolts 38 into the threads formed on the inner periphery of the shaft 34 inserted through the through hole 35.

  A washer 37 is sandwiched between the shaft 34 and the bolt 38. Since the diameter of the washer 37 is larger than the diameter of the through hole 35, the shaft 34 cannot be removed from the through hole 35 by tightening the bolt 38. The spring member 30 is integrated. In addition, if the length of the shaft 34 is changed, the height (length in the X direction in the figure) of the coil spring 33 when it is a single unit can be changed.

  In this embodiment, the upper plate 31 is the first plate in the claims, the lower plate 32 is the second plate in the claims, the coil spring 33 is the elastic body in the claims, and the shaft 34 is the shaft in the claims. The through hole 35 corresponds to the through hole in the claims, and the covering member 36 corresponds to the through hole covering member in the claims.

A2. Example operation:
Next, the operation of the spring member 30 in the fuel cell stack 100A of the present embodiment will be described based on FIG. FIG. 4 is an enlarged view of a portion X1 in FIG. 1 of the fuel cell stack 100A. 4A shows that the operation of the fuel cell stack 100A is stopped, and FIG. 4B shows that the fuel cell stack 100A is in operation.

  As shown in FIG. 4 (a), during the operation stop of the fuel cell stack 100A, the stacked body 14 is not stretched and has an initial length (length in the stacking direction (X direction)). 30 is also an initial state. That is, the washer 37 is in a position where it contacts the upper plate 31.

  During operation of the fuel cell stack 100A, each component of the stacked body 14 expands due to heat generated by power generation, so the length of the stacked body 14 in the stacking direction becomes long. Then, the laminated body 14 pushes the lower plate 32 of the spring member 30, but the upper plate 31 is pressed by the pressure plate 17 and the position is substantially fixed, so that the coil spring 33 contracts. That is, by disposing the spring member 30 between the laminate 14 and the end plate 18, the spring member 30 absorbs the change in the length of the laminate 14 in the stacking direction. Therefore, compared with the case where the spring member 30 is not disposed, the load (surface pressure) applied to the stacked body 14 when the stacked body 14 expands and contracts can be kept within a predetermined load range.

A3. Effects of the embodiment:
The effect of the fuel cell stack 100A of the present embodiment will be described in comparison with the fuel cell stack 100P of the comparative example. FIG. 5 is an explanatory view for explaining the effect of the fuel cell stack 100A, FIG. 6 is an explanatory view showing a configuration of a spring member 30P used in the fuel cell stack 100P of the comparative example, and FIG. 7 is a fuel cell stack 100P. It is the elements on larger scale for demonstrating the structure of this.

  The fuel cell stack 100P of the comparative example uses a spring member 30P instead of the spring member 30 in the fuel cell stack 100A of the first embodiment. Since the configuration of the fuel cell stack 100P other than the spring member 30P is the same as that of the fuel cell stack 100A of the first embodiment, description of the overall configuration of the fuel cell stack 100P is omitted. In FIGS. 6 and 7, the same components as those in the first embodiment are denoted by the same reference numerals.

  As shown in FIG. 6, the spring member 30 </ b> P mainly includes an upper plate 31 </ b> P, a lower plate 32 </ b> P, and a plurality of coil springs 33. The upper plate 31P is an aluminum flat plate having a substantially rectangular shape similar to that of the upper plate 31 of the first embodiment. Similar to the first embodiment, the upper surface of the upper plate 31P is opposed to the lower plate 32P. A plurality of spring holes 39u into which one end of the coil spring 33 is fitted are formed. The lower plate 32P is an aluminum flat plate having a substantially rectangular shape similar to the upper plate 31P. Further, on the opposite surface of the lower plate 32P facing the upper plate 31P, the spring hole 39l into which the other end of the coil spring 33 is fitted is provided on the opposite surface of the lower plate 32 of the first embodiment. The same number is drilled. When both ends of the coil spring 33 are fitted into the spring holes 39u and 39l, the spring member 30P is integrated by being positioned and fixed.

  During operation of the fuel cell stack 100P, if the heat distribution due to heat generated by power generation has a deviation in the stacking surface direction of the stack 14, the stack 14 may not expand uniformly. For example, as shown in FIG. 7, when the laminated surface of the laminated body 14 is inclined and expanded with respect to the upper plate 31, the lower plate 32P is pushed in an inclined state. Therefore, as illustrated, the lower plate 32P may be displaced in the Z-axis direction in the drawing with respect to the surface direction of the upper plate 31P.

  Then, the coil spring 33 contracts obliquely with respect to the stacking direction (X direction). Therefore, the pressing force with which the coil spring 33 pushes the lower plate 32P due to the expansion and contraction of the coil spring 33 is inclined with respect to the stacking direction as indicated by the solid arrow in FIG. That is, since the pressing force that pushes the laminated surface of the laminated body 14 is dispersed as shown by the broken line arrows in FIG. 7, there is a possibility that a desired load along the lamination direction of the laminated body 14 cannot be obtained. In addition, an unnecessary load may be applied in a direction (Z direction) perpendicular to the stacking direction.

  On the other hand, in the fuel cell stack 100A of the present embodiment, the spring member 30 is integrated in a state where the shaft 34 is inserted through the through hole 35. Therefore, as shown in FIG. 5, even if the laminated body 14 expands in the same manner as described above, the laminated surface is inclined with respect to the opposed surface of the upper plate 31, and the opposed surface of the lower plate 32 is Even if it is inclined with respect to the opposing surface of the upper plate 31, the inclination and deviation are limited by the through hole 35 and the shaft 34.

  Therefore, as indicated by solid line arrows in FIG. 5, the pressing force by which the coil spring 33 presses the lower plate 32 due to the expansion and contraction of the coil spring 33 is slightly inclined with respect to the stacking direction (X direction). That is, as indicated by broken line arrows in FIG. 5, the pressing force with which the coil spring 33 presses the lower plate 32 is hardly dispersed and is applied in the stacking direction. Therefore, it can suppress that the load along the lamination direction (X direction) of the laminated body 14 reduces. Moreover, it can suppress that an unnecessary load is applied to the direction (Z direction) perpendicular | vertical to a lamination direction. 5 and 7, the inclination of the laminated body 14 and the displacement of the lower plate 32 are shown slightly larger for the sake of clarity.

  Further, as shown in FIG. 5, when the shaft 34 moves obliquely with respect to the through hole 35, the through hole 35 and the shaft 34 come into contact with each other, and the corners of the through hole 35 are scraped or contacted. There is a possibility that an extra load is applied to the laminate 14 due to the frictional force. To solve this problem, it is conceivable to increase the diameter of the through hole 35 so that the shaft 34 and the through hole 35 do not come into contact with each other. However, when the diameter of the through-hole 35 is increased, the range in which the shaft 34 can move in the direction of the stacking surface of the stacked body 14 is widened, which may increase the amount of deviation between the upper plate 31 and the lower plate 32.

  On the other hand, the spring member 30 of this embodiment includes a covering member 36 that covers the inner periphery of the through hole 35. The friction coefficient of the POM covering member 36 with respect to the shaft 34 rather than the friction coefficient (including the static friction coefficient and the dynamic friction coefficient) with respect to the nickel-phosphorus alloy-plated iron shaft 34 of the through hole 35 provided in the aluminum upper plate 31 Is smaller. Therefore, as shown in FIG. 5, even when the shaft 34 is in contact with the covering member 36, the frictional force acting on the contact portion is smaller than that without the covering member 36. Therefore, it is possible to reduce an extra load on the laminate 14 due to the frictional force. Further, it is possible to suppress the deterioration of the spring member 30 due to the frictional force by cutting the corner of the opening portion of the through hole 35 by providing the covering member 36.

B. Second embodiment:
B1. Example configuration:
FIG. 8 is an explanatory diagram showing the configuration of the fuel cell stack 100B of the present embodiment. As shown in the figure, the fuel cell stack 100B of the present embodiment uses a spring member 30B instead of the spring member 30 in the fuel cell stack 100A of the first embodiment. The configuration is the same as that of the fuel cell stack 100A of the embodiment. Therefore, the same reference numerals are given to the same components as those of the fuel cell stack 100A of the first embodiment, and the description thereof is omitted.

B1-1. Configuration of the spring member 30B:
FIG. 9 is a perspective view showing the overall configuration of the spring member 30B, and FIG. 10 is an explanatory view schematically showing an AA cut surface in FIG. As shown in FIGS. 9 and 10, the spring member 30 </ b> B mainly includes an upper plate 31 </ b> B, a lower plate 32, a plurality of coil springs 33, a shaft 34 </ b> B, a washer 37, and a bolt 38. In the spring member 30B of the present embodiment, the configuration of the upper plate 31B and the length of the shaft 34B are different from those of the spring member 30 of the first embodiment, but other configurations are the same as in the spring member 30 of the first embodiment. Therefore, the same reference numerals as those in the first embodiment are used, and the description thereof is omitted.

  As shown in FIG. 9, the upper plate 31 </ b> B is an aluminum flat plate having a substantially rectangular shape similar to that of the first embodiment. A through hole 35B is provided at the same location as the upper plate 31 of the first embodiment. Further, the upper plate 31B communicates with the through-hole 35B, forms a substantially cylindrical cavity concentric with the through-hole 35B, and has a larger diameter than the through-hole 35B and opens on the end plate 18 side surface. A recess 40 is provided. The diameter of the recess 40 is slightly larger than the diameter of the washer 37. In addition, the washer 37 and the bolt 38 in this embodiment correspond to the fastener in the embodiment, and the recess 40 corresponds to the recess in the claims.

  Then, like the spring member 30 of the first embodiment, one end of the coil spring 33 is fitted into the spring hole 391 of the lower plate 32 and the other end of the coil spring 33 is fitted into the spring hole 39u of the upper plate 31B. The spring member 30B is integrated by fastening the bolt 38 to the shaft 34B inserted through the through hole 35 via the washer 37. At this time, as shown in FIG. 10, the head of the bolt 38 is buried in the recess 40 and does not protrude from the surface of the upper plate 31B on the end plate 18 side. In the integrated state, the distance between the upper plate 31B and the lower plate 32 in the spring member 30B of this embodiment is equal to the distance between the upper plate 31 and the lower plate 32 in the spring member 30 of the first embodiment.

B2. Example operation:
Next, the operation of the spring member 30B in the fuel cell stack 100B of the present embodiment will be described based on FIG. FIG. 11 is an enlarged view of a portion X1 in FIG. 8 of the fuel cell stack 100B. 11A shows that the operation of the fuel cell stack 100B is stopped, and FIG. 11B shows that the fuel cell stack 100B is in operation.

  As shown in FIG. 11A, during the operation stop of the fuel cell stack 100B, the stacked body 14 is not expanded and contracted and has an initial length (length in the stacking direction (X direction)). 30B is also an initial state. That is, the head of the bolt 38 is buried in the recess 40, and the top surface of the head of the bolt 38 is in a position that coincides with the surface of the upper plate 31B on the end plate 18 side.

  During operation of the fuel cell stack 100B, each component of the stacked body 14 expands due to heat generated by power generation, so that the length of the stacked body 14 in the stacking direction increases. Then, the laminated body 14 pushes the lower plate 32 of the spring member 30B, but the upper plate 31B is pressed by the pressure plate 17 and the position is substantially fixed, so that the coil spring 33 contracts. As shown in FIG. 11B, the shaft 34B protrudes from the upper plate 31B by the amount that the coil spring 33 contracts.

B3. Effects of the embodiment:
The effect of the fuel cell stack 100A of the present embodiment will be described in comparison with the fuel cell stack 100A of the first embodiment. For example, in the first embodiment, as shown in FIG. 4, when the laminated body 14 expands, the laminated body 14 becomes a maximum length Ls in the lamination direction (X direction in the figure). And the distance between the upper surface of the head of the bolt 38 and the upper plate 31 is Lh. When the laminated body 14 expands to the maximum extent, if a margin of a distance Lr is provided between the upper surface of the head of the bolt 38 and the end plate 18, the distance L1 between the end plate 18 and the upper plate 31 is It is preferable to leave at least the length (Ls + Lh + Lr). If it is left as it is, the head of the bolt 38 does not come into contact with the end plate 18 when the laminated body 14 is expanded to the maximum, so that no load is applied to the laminated body 14 by the end plate 18.

  On the other hand, in the second embodiment, as shown in FIG. 11, when the laminated body 14 expands, the maximum length is increased by the length Ls in the stacking direction. When the body 14 is expanded to the maximum extent, if a margin of a distance Lr is provided between the upper surface of the head of the bolt 38 and the end plate 18, the distance L2 between the end plate 18 and the upper plate 31B is increased. It is only necessary to leave as much as (Ls + Lr). If it is left as much as it is, the load by the end plate 18 will not be applied when the laminate 14 expands to the maximum extent.

  As described above, the first and second embodiments have the same configuration except for the spring members 30 and 30B, and the upper plate 31 (31B) in the initial state of the spring members 30 and 30B. The distance between the lower plates 32 is equal. Therefore, the length in the stacking direction of the entire fuel cell stacks 100A and 100B is determined by the distance between the upper plate 31 (31B) and the end plate 18. Therefore, the fuel cell stack 100B of the second embodiment can be made shorter in the stacking direction by Lh than the fuel cell stack 100A of the first embodiment. That is, in the spring member 30B in the present embodiment, the concave portion 40 is formed in the upper plate 31B so that the head of the bolt 38 is buried, so that the fuel cell is more than the fuel cell stack 100A of the first embodiment. The stack 100B can be reduced in size.

C. Third embodiment:
The fuel cell stack of the present embodiment uses a spring member 30C instead of the spring member 30 in the fuel cell stack 100A of the first embodiment, but the other configuration is the fuel cell of the first embodiment. The configuration is the same as that of the stack 100A. Therefore, hereinafter, the spring member 30C will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the structure same as the spring member 30 in a 1st Example, and the description is abbreviate | omitted.

C1. Configuration of the spring member 30C:
FIG. 12 is an explanatory diagram showing a cross-sectional configuration by enlarging a part of the spring member 30C. Similar to the spring member 30 in the first embodiment, the spring member 30C in the present embodiment includes an upper plate 31C, a lower plate 32C, a plurality of coil springs 33, a shaft 34, a washer 37, and a bolt 38. Is mainly provided. The upper plate 31C of this embodiment is different from the upper plate 31 of the first embodiment in that it includes a POM (polyacetal) spring hole covering member 41u that covers the inside of the spring hole 39u. The lower plate 32C of the embodiment is different from the lower plate 32 of the first embodiment in that it includes a spring hole covering member 41l made of POM that covers the inside of the spring hole 39l. The spring hole covering members 41u and 41l in the present embodiment correspond to the spring hole covering members in the claims.

C2. Effects of the embodiment:
As described above, in the spring member 30C according to the present embodiment, the spring holes 39u and 39l provided in the upper plate 31C and the lower plate 32C are covered with the spring hole covering members 41u and 41l made of POM, respectively. As described above, the coil spring 33 is made of spring steel, and the upper plates 31C and 32C are made of aluminum. The friction coefficient of the coil spring 33 with respect to the spring hole covering members 41u and 41l is smaller than the friction coefficient of the coil spring 33 with respect to the spring holes 39u and 39l of the upper plates 31C and 32C. Therefore, even if the laminated body 14 is inclined and expands, and the coil spring 33 contracts obliquely and displaces in contact with the spring hole covering members 41u and 41l, it displaces in contact with the spring holes 39u and 39l. Compared with the case where it does, the frictional force which arises in the coil spring 33 becomes small. Therefore, it is possible to suppress the wear of the spring due to friction.

D. Fourth embodiment:
The fuel cell stack of the present embodiment uses a spring member 30D instead of the spring member 30 in the fuel cell stack 100A of the first embodiment, but the other configuration is the fuel cell of the first embodiment. The configuration is the same as that of the stack 100A. Therefore, below, spring member 30D is demonstrated based on FIG. In addition, the same code | symbol is attached | subjected to the structure same as the spring member 30 in a 1st Example, and the description is abbreviate | omitted.

D1. Configuration of the spring member 30D:
FIG. 13 is an explanatory diagram showing a cross-sectional configuration by enlarging a part of the spring member 30D. Similar to the spring member 30 in the first embodiment, the spring member 30D in the present embodiment includes an upper plate 31D, a lower plate 32D, a plurality of coil springs 33, a shaft 34, a washer 37, and a bolt 38. Is mainly provided. The spring member 30D of this embodiment is different from the spring member 30 of the first embodiment in the shapes of a spring hole 39uD provided in the upper plate 31D and a spring hole 39lD provided in the lower plate 32D. As shown in the figure, the spring holes 39uD and 391D of this embodiment have rounded corners of the openings.

D2. Effects of the embodiment:
As described above, in the spring member 30D in the present embodiment, the spring holes 39uD and 391D provided in the upper plate 31D and the lower plate 32D are rounded at the corners of the openings. Therefore, even if the laminated body 14 is inclined and expands and the coil spring 33 contracts obliquely, it is difficult to contact the spring holes 39uD and 391D. Therefore, it is possible to suppress the wear of the spring due to friction.

E. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

  (1) In the above-described embodiment, the coil spring 33 is used as the elastic body disposed between the upper plate 31 and the lower plate 32. However, the present invention is not limited to this, for example, a disc spring, rubber, sponge, etc. Various elastic bodies can be used. Even when such an elastic body is used, the same effect can be obtained by using the above-described embodiment.

  (2) In the above-described embodiment, the upper plate 31 made of aluminum, the lower plate 32, the shaft 34 made of iron, the coil spring 33 made of spring steel, the covering member 36 made of POM, and the spring hole covering members 41u and 41l. Although used, it is not limited to those materials. For example, the covering member 36 may be selected from a material whose friction coefficient with respect to the shaft 34 of the covering member 36 is smaller than the friction coefficient with respect to the shaft 34 of the through hole 35 of the upper plate 31, and is not limited to plastic. It may be a rubber material, ceramic, or metal.

  (3) In the above-described embodiment, the spring member 30 is disposed between the stacked body 14 and the end plate 18. However, for example, the spring member 30 may be disposed between the stacked body 14 and the end plate 11. The two spring members 30 may be disposed both between the laminate 14 and the end plate 11 and between the laminate 14 and the end plate 18. Further, the spring member 30 may be disposed in place of the end plate 11 and the end plate 18. By doing so, the length of the entire fuel cell stack 100 in the stacking direction can be shortened.

  (4) In the above-described embodiment, the shaft 34 is formed at a total of six locations near the four corners and the center of the lower plate 32, and the through holes 35 are also provided at the same locations on the upper plate 31. However, the number and arrangement of these are not limited to the above-described embodiments. For example, one shaft 34 may be provided at the center of the lower plate 32 and only one through hole 35 may be provided at the center of the upper plate 31. Even if it does in this way, it can control that upper plate 31 and lower plate 32 shift greatly.

  (5) In the fourth embodiment, the corners of the openings of the spring holes 39uD and 39lD are rounded. For example, the shapes of 39uD and 39lD are directed from the bottom to the opening. A shape that expands in a tapered shape (the shape of the hole is a truncated cone shape) may be used. Even if it does in this way, when the coil spring 33 expands and contracts diagonally, it becomes difficult to contact the spring holes 39uD and 391D, so that it is possible to prevent the spring from being worn by friction.

  (6) In the above-described embodiment, the lower plate 32 is positioned closer to the laminated body 14 than the upper plate 31, but the upper plate 31 is positioned closer to the laminated body 14 than the lower plate 32. Also good. In that case, when the laminated body 14 expands, the coil spring 33 contracts and the shaft 34 protrudes from the upper plate 31 toward the laminated body 14. Therefore, for example, when the upper plate 31 and the lower plate 32 are formed larger than the size of the laminated surface of the laminated body 14, the shaft 34 is projected from the peripheral portion thereof, and the spring member 30 is configured, the shaft 34 Is arranged around the laminate 14. Then, even if the shaft 34 protrudes toward the laminated body 14, it does not hit the laminated body 14. Further, since it is not necessary to provide a space between the lower plate 32 and the end plate 18, the length of the fuel cell stack 100 in the stacking direction (X direction in the figure) can be shortened.

  (7) In the above embodiment, the spring hole 39l is provided in the upper plate 31 and the spring hole 39u is provided in the lower plate 32 to determine the position of the coil spring 33. For example, the upper plate 31 and the lower plate 32 are provided with The position of the coil spring 33 may be determined by providing a protrusion and inserting the protrusion into a ring of the coil spring 33.

  (8) In the above-described embodiment, the washer 37 and the bolt 38 are used as the fastener that prevents the shaft 34 from coming out of the through hole 35, but the fastener is not limited to this. For example, only a bolt whose head is larger than the opening area of the through hole 35 may be used. Even in this case, the head of the bolt can be caught by the upper plate 31 so that the shaft 34 does not come out of the through hole 35. Alternatively, a through hole may be provided perpendicular to the length direction of the shaft 34, a pin may be inserted into the through hole, and the shaft 34 may be secured so as not to come out of the through hole 35 by the pin.

It is explanatory drawing which shows the structure of 100 A of fuel cell stacks as 1st Example of this invention. FIG. 3 is a perspective view showing an overall configuration of a spring member 30. It is explanatory drawing which shows typically the AA cut surface in FIG. FIG. 2 is an enlarged view of a portion X1 in FIG. 1 of a fuel cell stack 100A. It is explanatory drawing for demonstrating the effect of fuel cell stack 100A. It is explanatory drawing which shows the structure of the spring member 30P used for the fuel cell stack 100P of a comparative example. It is the elements on larger scale for demonstrating the structure of the fuel cell stack 100P. It is explanatory drawing which shows the structure of the fuel cell stack 100B as 2nd Example of invention. It is a perspective view which shows the whole structure of the spring member 30B. It is explanatory drawing which shows typically the AA cut surface in FIG. FIG. 9 is an enlarged view of part X1 in FIG. 8 of the fuel cell stack 100B. It is explanatory drawing which expands a part of spring member 30C, and shows a cross-sectional structure. It is explanatory drawing which expands a part of spring member 30D and shows a cross-sectional structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 18 ... End plate 12, 16 ... Insulation plate 13, 15 ... Current collecting plate 14 ... Laminated body 14m ... MEA
14s ... Separator 17 ... Pressure plate 19 ... Tension plate 20 ... Bolt 21 ... Adjust screw 30, 30B, 30C, 30D, 30P ... Spring member 31, 31B, 31C, 31D, 31P ... Upper plate 32, 32C, 32D, 32P ... Lower plate 33 ... Coil spring 34, 34B ... Shaft 35, 35B ... Through hole 36 ... Cover member 36n ... Claw 37 ... Washer 38 ... Bolt 39l, 39u, 39lD, 39uD ... Spring hole 40 ... Recessed 41l, 41u ... Spring hole covered Member 100, 100A, 100B, 100P ... Fuel cell stack

Claims (8)

A power generation body in which electrodes are disposed on both surfaces of an electrolyte membrane includes a multilayer body in which a plurality of layers are stacked, and a telescopic member that is disposed at an end of the multilayer body and can expand and contract in the stacking direction of the multilayer body. A fuel cell stack,
The elastic member is
A first plate;
A second plate disposed opposite the first plate;
An elastic body disposed between the first plate and the second plate;
A shaft protruding from the second plate;
With
The first plate includes
The shaft through hole is formed to be inserted, the diameter of the through hole is larger than the diameter of said shaft, said shaft, characterized in can der Rukoto be moved obliquely with respect to the through hole Fuel cell stack. The fuel cell stack according to claim 1, wherein
The fuel cell stack, wherein the second plate is located closer to the stacked body than the first plate. The fuel cell stack according to claim 1 or 2,
The elastic member is
Further comprising a through-hole covering member covering the inner periphery of the through-hole,
The fuel cell stack, wherein a friction coefficient of the through hole covering member with respect to the shaft is smaller than a friction coefficient of the through hole of the first plate with respect to the shaft. The fuel cell stack according to claim 3,
The fuel cell stack, wherein the through hole covering member is made of resin. The fuel cell stack according to any one of claims 1 to 4,
The elastic member is
A fastener for fastening the shaft so as not to come out of the through hole;
The first plate is
The fuel cell stack further comprising a recess communicating with the through hole and receiving at least a part of the fastener. The fuel cell stack according to any one of claims 1 to 5,
The elastic body is
A coil spring,
The first and second plates include
A concave spring hole is formed that opens on each facing surface.
The spring hole is
A fuel cell stack, wherein the diameter of the fuel cell stack increases from the bottom surface toward the opening. The fuel cell stack according to any one of claims 1 to 5,
The elastic body is
A coil spring,
The first and second plates include
A concave spring hole is formed in each facing surface, and a concave spring hole is formed.
A spring hole covering member that covers the inner periphery of the spring hole;
A fuel cell stack, wherein a coefficient of friction of the spring hole covering member with respect to the coil spring is smaller than a coefficient of friction of the spring hole provided in the first and second plates with respect to the coil spring. The fuel cell stack according to claim 7,
The fuel cell stack, wherein the spring hole covering member is made of resin.

Images