JP2009059535A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide fuel cell in which a deterioration of a battery performance due to normalization of a cell combination force can be controlled and a failure due to a shock can be solved as well. <P>SOLUTION: The fuel cell 10 is provided with a fixing plate 120 on an outer side of an end plate 110, and the fixing plate 120 has, on its side facing the end plate 110, an inclined surface 122S which is inclined against a cell lamination direction. The fixing plates 120 are arranged on both ends of a fuel cell stack, and the inclined surfaces 122S are made to face each other so that a distance between the inclined surfaces can be wider on the one end side of the end plate 110 and narrower one the other end. Between the end plate 110 and the fixing plate 120 there is arranged a rolling roller 112, and the rolling roller 112 rolls on the inclines surface 122S by an external force rendered in crossing a the cell lamination direction and moves the fuel cell stack between the fixing plates toward a narrower side of the inclined surface distance. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell in which a plurality of fuel cells are stacked between end plates.

  Such a fuel cell is being mounted on a moving body such as a vehicle. For example, when mounting a vehicle, various countermeasures against an impact that may be applied while the vehicle is running have been proposed (for example, Patent Document 1). ). In this patent document, the impact applied to the fuel cell from the direction intersecting the cell stacking direction is mitigated by an energy absorbing part away from the fuel cell mounting location, a buffer material disposed close to the fuel cell, or the like. .

Japanese Patent Laid-Open No. 2003-123779

  By the way, the fuel cells are fastened along the stacking direction regardless of whether or not there is an impact. The degree of fastening, that is, the magnitude of the fastening force, is such that the cell surface pressure due to the fastening force causes damage to the membrane electrode assembly. It is often limited to the extent that it does not occur. By doing so, a decrease in battery performance is suppressed. On the other hand, even if the impact is mitigated as described above, the impact is still applied to the fuel cell from the direction intersecting the cell stacking direction. For this reason, depending on the degree of impact, there is a concern that the fuel cells in the stacked state may be displaced. In order to avoid such a situation, it is effective to increase the fastening force along the stacking direction of the fuel cells in advance, but the cell surface pressure increases due to the fastening force increase, and the membrane electrode assembly is damaged. As battery performance is expected to decline due to the above, there is a limit to dealing with impacts due to increased fastening force.

  In view of the above-described problems, an object of the present invention is to achieve both the suppression of a decrease in battery performance with an appropriate cell fastening force and the handling of a malfunction when an impact is applied to a fuel cell.

  In order to achieve at least a part of the above object, the present invention adopts the following configuration.

[Application: Fuel cell]
A fuel cell in which a plurality of fuel cells are stacked between end plates,
In order to maintain the stacking state of the fuel cells, the end plate is restrained along the stacking direction of the fuel cells, and an initial fastening force along the stacking direction is applied to the fuel cells via the end plate. With a fastening force applying mechanism to be applied to
The fastening force applying mechanism is:
When an external force is applied to the fuel cell from a direction crossing the stacking direction, a fastening force larger than the initial fastening force in the absence of the external force is applied to the fuel cell via the end plate. And

  In the fuel cell having the above configuration, since the initial fastening force along the stacking direction is applied to the fuel cell through the end plate by the fastening force applying mechanism, the initial fastening force does not cause damage to the membrane electrode assembly. If so, a decrease in battery performance can be suppressed. On the other hand, when an external force is applied to the fuel cell from a direction crossing the cell stacking direction, in the situation where the external force is applied, a fastening force larger than the initial fastening force when there is no external force is applied to the fuel cell via the end plate. Since it gives to a cell, the malfunction called the shift | offset | difference of the laminated | stacked fuel battery cell can be effectively suppressed by fastening force increase. In addition, since the increase in the fastening force is brought about only when the above-described external force is applied, a decrease in battery performance can be suppressed by an appropriate initial fastening force during normal operation in which no external force is applied. In this case, when the external force once applied disappears, if the fastening force is returned to the initial fastening force, the increase in the fastening force is also quickly eliminated, which is beneficial in suppressing the deterioration of the battery performance.

  The fuel cell described above can be configured as follows. For example, the fastening force applying mechanism includes a pair of fixing plates positioned outside the end plate, and fixes an interval between the plates, and an engagement member between the fixing plate and the end plate. With the engagement member engaged, the fixed plate and the end plate are engaged with each other, and the initial fastening force is transmitted from the fixed plate to the end plate. When the external force is applied, the engaging member is displaced to the engagement state between the fixed plate and the end plate, so that a fastening force larger than the initial fastening force is applied from the fixed plate to the end. Communicate to the plate. In this way, it is possible to easily cope with a problem such as a shift of the cell due to an increase in the fastening force, simply by configuring the engagement member to be displaced when an external force is applied.

  Such a displacement in the engaged state can be easily achieved as follows. For example, in the pair of fixed plates, the side facing the end plate is an inclined surface inclined with respect to the stacking direction, and the inclined surface is wide at one end of the end plate and narrow at the other end. Make them face each other. The engaging member is interposed between each of the end plates and the fixed plate, and moves along the inclined surface, thereby stacking the fuel cells between the end plates and the end plates. The initial fastening force is allowed to move between the opposing inclined surfaces, and the initial fastening force is applied to the fixed plate when the end plate and the fuel cell in the stacked state are positioned on the wide side of the opposing inclined surfaces. When the external force is applied to the end plate, the stacked end plate and the fuel cell are moved along the inclined surface so that the opposed inclined surface moves to the narrower side. . That is, the engagement member moves by moving along the inclined surface of the engaging member from the wide side of the inclined surface where the end plate and the fuel cell in the stacked state face each other to the narrow side. Since the end plate and the fuel cell in a stacked state are restrained by a fixing plate and sandwiched between inclined surfaces with a narrow interval, a fastening force larger than the initial fastening force is applied to the fixing plate. You will receive it from the side. As a result, it is possible to easily cope with a problem caused by an increase in fastening force. The movement along the inclined surface caused by the engaging member occurs when the engaging member rolls on the inclined surface or slides on the inclined surface.

  In this case, each of the pair of fixed plates is provided with two inclined surfaces having the inclined surfaces opposite to each other in the inclination direction, and the engaging member is provided on each of the two inclined surfaces having the opposite inclination directions. It can be interposed between the end plate and the fixed plate so as to move (eg, roll). In this way, even if the direction of the external force applied across the cell stacking direction is opposite, the end plate and the fuel cell in the stacked state are inclined surfaces having a narrow interval along the direction in which the external force is applied. Will move to the side. That is, the versatility with respect to the direction of the external force is increased by the amount of the inclined surface having the opposite inclination direction, so that the degree of freedom in mounting the fuel cell is increased.

  Further, as another mode of causing the engagement state to be displaced, for example, the pair of fixing plates are positioned on the side of the first fixing plate fixed to one end plate and the other end plate. A second fixed plate having a curved surface that is concave toward the center of the plate, and the engaging member is interposed between the second fixed plate and the other end plate. By rolling on the curved surface, the end plate and the fuel battery cell between the end plates are bent while being stacked between the first fixed plate and the second fixed plate, and the end in the stacked state When the plate and the fuel cell are positioned at the center of the curved surface, the initial fastening force is transmitted from the second fixed plate to the end plate, and when the external force is applied, The fuel cell and the end plates in a stacked state to roll to deflect off-center of the curved surface. In other words, the end plate and the fuel cell in the stacked state are displaced from the center of the curved surface by the movement (for example, rolling) along the curved surface of the engaging member, thereby being brought into the engaged state by the engaging member. Cause displacement. This bend is obtained by stacking the end plate and the fuel cell after one end plate is fixed to the first fixing plate, and bending on the other side, that is, the side where the above-described bending occurs. Since it is restrained by the second fixed plate having the surface, the bent end plate and the fuel cell receive a fastening force larger than the initial fastening force from the side of the fixed plate. . As a result, it is possible to easily cope with a problem caused by an increase in fastening force.

  In this case, if the curved surface is a spherical surface, the end plate and the fuel cell in the stacked state bend in the direction in which the external force is applied regardless of the direction of the external force applied across the cell stacking direction. Become. That is, since the versatility with respect to the direction of the external force is increased, the degree of freedom in how to mount the fuel cell is increased.

  Hereinafter, embodiments of the present invention will be described based on examples. FIG. 1 is an explanatory diagram schematically showing the overall configuration of a fuel cell 10 as an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the periphery of a fixed plate 120 and an end plate 110, which are the main parts of the fuel cell 10. 3 is an explanatory diagram showing a partially broken state of the fuel cell 10 in a steady state, and FIG. 4 is an explanatory diagram showing a partially broken behavior of the fuel cell 10 when an external force is applied across the cell stacking direction. It is.

  As shown in FIG. 1, the fuel cell 10 includes a plurality of fuel cells 100 stacked between upper and lower end plates 110 in the drawing. In this case, a current collecting plate 102 is disposed between the end plate 110 and the fuel cell 100. Each fuel cell 100 includes a membrane electrode assembly (MEA) (not shown) in which electrodes are joined to both sides of an electrolyte membrane, and a porous gas diffusion layer on both sides, and a separator is provided. Have. The MEA, the gas diffusion layer and the separator are not directly related to the gist of the present invention, so the illustration is simplified and the description thereof is also omitted.

  The fuel cell 10 includes a fixed plate 120 on the outer side of the end plate 110 in order to maintain the engagement of the fuel cell 100 and to secure a stacked state. The fixed plates 120 at both ends of the fuel cell are fixed in three directions by an H-shaped reinforcing material 140, and the interval between the fixed plates is predetermined. The plate interval is determined so that the number of stacked cells and the fuel cell 100 can receive an appropriate surface pressure and can perform power generation operation without any problem, which will be described later. The reinforcing member 140 may be variously adopted as long as it can reinforce the fixed plate 120 and maintain the distance between the fixed plates.

  As shown in FIG. 2, one fixed plate 120 has an inclined surface 122S that is inclined with respect to the cell stacking direction on the side facing the end plate 110, and includes a raised portion 124 on the inclined front end side. Although the other fixed plate 120 has the same shape, the fixed plates 120 at both ends of the fuel cell end with the inclined surfaces 122S on the end when the fixed plates are fixed by the reinforcing member 140 described above. It is made to oppose so that a space | interval may be wide on the one end side of the plate 110, more specifically, the side of the protruding part 124, and a space | interval may become narrow on the other end side.

  The end plate 110 has a bottom surface that is an inclined surface that follows the inclined surface 122S of the fixed plate 120, and includes rolling rollers 112 at the corners of the plate 4. The rolling roller 112 is composed of a roller bearing or the like, and is interposed between the end plate 110 and the fixed plate 120 and rolls on the inclined surface 122S. That is, the rolling roller 112 rolls on the inclined surface 122S, so that the fuel cell 100 stacked between the end plate 110 and the plate moves between the opposed inclined surfaces 122S in the stacked state. Make it possible. For convenience of explanation, the fuel cell 100 stacked between the end plate 110 and the plate will be referred to as a fuel cell stack in the following explanation.

  As shown in FIG. 3, the fuel cell 10 includes a spring member 130 on the opposite side of the raised portion 124 of the fixed plate 120. Since the spring member 130 exerts its urging force on the fuel cell stack, the fuel cell stack is normally positioned on the raised portion 124 side. In this embodiment, the urging force of the spring member 130, the interval between the fixed plates 120, and the inclination of the inclined surface 122S are set to an appropriate cell surface pressure for ensuring the number of stacked cells and the steady power generation operation of the fuel cell 100. Was determined in consideration of In the steady state power generation operation, the fuel cell stack has an initial position where the rolling roller 112 is in contact with the raised portion 124 as shown in FIG. 3 (that is, a position on the opposite inclined surface 122S on the side where the interval is wide). When the fuel cell stack is in this initial position, the fastening force (initial fastening force) indicated by the black arrow in the figure is transferred from the fixed plate 120 via the rolling roller 112 due to the interval between the fixed plates. To the end plate 110. Therefore, in the situation where the fuel cell stack is located at the initial position shown in FIG. 3, each fuel cell 100 receives the above-described initial fastening force via the end plate 110, and is appropriate for this initial fastening force. The power generation operation is performed without hindrance due to a large cell surface pressure.

  Now, as shown in FIG. 4, it is assumed that an external force indicated by an outlined arrow in the drawing is applied across the cell stacking direction. Such a situation is assumed, for example, when an impact is applied to the vehicle from the front-rear direction after the fuel cell 10 is mounted on the vehicle and the direction intersecting the cell stacking direction is the front-rear direction of the vehicle. . Since this external force acts on the fuel cell stack from the right to the left in the figure, in response to this external force, the rolling roller 112 rolls toward the side where the interval between the inclined surfaces 122S facing each other on the inclined surface 122S is narrow. Even in the fuel cell stack, the opposed inclined surface 122S moves to the narrower side. In this case, the fuel cell stack moves to the side where the inclined surface interval is narrow while shrinking the spring member 130.

  Then, the fuel cell stack is moved by the above-described rolling of the rolling roller 112, and the engagement state between the fixed plate 120 and the fuel cell stack by the rolling roller 112 is displaced. After being constrained by the fixed plate 120, it is sandwiched between inclined surfaces with a narrow interval between inclined surfaces. Therefore, the fuel cell stack has a fastening force larger than the initial fastening force that is received when the stack is located on the side of the raised portion 124 having the wide inclined surface interval (that is, the fastening force in a situation where no external force is received), It will be received from the fixed plate 120 side at both ends. As a result, it is possible to effectively suppress problems such as misalignment of each fuel cell 100 in the fuel cell stack by temporarily increasing the fastening force when an external force is input. Moreover, this increase in fastening force occurs only when the above-described external force is applied and the fuel cell stack moves to the side where the inclined surface interval is narrow, so that an appropriate initial fastening force can be obtained during normal operation where no external force is applied. Thus, it is possible to suppress a decrease in battery performance in each of the fuel battery cells 100.

  Further, in this embodiment, once the applied external force disappears, the spring member 130 exerts the spring force on the fuel cell stack, so that the fuel cell stack moves to the side where the inclined surface interval is wide, that is, the raised portion 124 side. To return to the initial position. For this reason, the increase in the fastening force is quickly eliminated after the external force disappears, and the force received by the fuel cell 100 returns to the initial fastening force. Therefore, the decrease in the battery performance due to the increase in the surface pressure in each cell is quickly suppressed after the external force disappears. it can.

  Next, another embodiment will be described. FIG. 5 is an explanatory view schematically showing the overall configuration of a fuel cell 10A as another embodiment, and FIG. 6 is an explanatory view showing a fixed plate 120A, which is a main part of the fuel cell 10A, through the end plate 110A. 7 is an explanatory diagram showing a partially broken state of the fuel cell 10A when no external force is input. This embodiment is characterized in that, when an external force is applied crossing the cell stacking direction, a countermeasure is taken even when the direction of the external force is reversed.

  As shown in the figure, the fuel cell 10A includes a fuel cell stack in which a plurality of fuel cells 100 are stacked, restrained by upper and lower fixing plates 120A in the figure, like the fuel cell 10 described above. Unlike the fixed plate 120 described above, the fixed plate 120A includes two inclined surfaces 122RS and 122LS having opposite directions of inclination on the end plate 110A side, as shown in detail in FIG. Both inclined surfaces are formed by dividing the end plate 110A side of the fixed plate 120A into two. Even in the fixed plate 120A, since they face each other as shown in FIG. 5, the two fixed plates facing each other have their inclined surfaces 122RS spaced widely on one end side of the end plate 110A and spaced on the other end side. Oppositely, the inclined surfaces 122LS face each other so that the interval is narrow on one end side of the end plate 110 and the interval is wide on the other end side.

  The end plate 110A is provided with a first bottom portion 110RB and a second bottom portion 110LB that are divided into two according to the two inclined surfaces, and the first and second bottom portions have their bottom surfaces inclined with respect to the fixed plate 120. It is an inclined surface that follows the surface 122RS or the inclined surface 122LS, and includes rolling rollers 112 at the four corners of each bottom. The rolling roller 112 is configured by a roller bearing or the like, and rolls on the inclined surfaces 122RS and 122LB, respectively, interposed between the first and second bottom portions of the end plate 110A and the fixed plate 120A. That is, the rolling roller 112 of the first bottom portion 110RB rolls in the same direction along the respective inclined surfaces on the inclined surface 122RS, and the rolling roller 112 of the second bottom portion 110LB rolls in the same direction along the inclined surface 122LS. The fuel cell stack in between moves between the inclined surface 122RS and the inclined surface 122LS facing each other.

  As shown in FIG. 7, the fuel cell 10A exerts a biasing force of the spring member 130 on both sides of the fuel cell stack, and normally places the fuel cell stack at the intersection of the inclined surfaces 122RS and 122LB. That is, in this embodiment, the intersection of the inclined surfaces is the initial position during steady power generation operation, and when the fuel cell stack is at the initial position shown in the figure, the black plate is shown in the figure due to the interval between the fixed plates described above. A fastening force (initial fastening force) indicated by an arrow is transmitted from the fixed plate 120A to the end plate 110A via the rolling roller 112.

  In the fuel cell 10A of this embodiment, even when the external force indicated by the white arrow in the horizontal direction shown in FIG. 7 is applied across the cell stacking direction, the external force is applied in the same manner as the fuel cell 10 described above. This will increase the fastening force. That is, when an external force R in the figure is applied, the rolling roller 112 receives the external force R and rolls toward the side where the interval between the inclined surfaces facing each other on the inclined surface 122RS is narrow. On the other hand, when the external force L in the figure is applied, the rolling roller 112 rolls toward the side where the interval between the inclined surfaces facing each other on the inclined surface 122LS is narrow. When such roller rolling occurs, the fastening force increases as in the above-described embodiment. Therefore, even if an external force is input from either the left or right direction in FIG. It is possible to achieve both the suppression of inconveniences such as misalignment of each fuel battery cell 100 in the fuel cell stack due to the increase and the suppression of deterioration in battery performance.

  Moreover, even in this embodiment, since the increase in the fastening force is quickly eliminated after the external force disappears by the spring members 130 arranged on both sides of the fuel cell stack, there is an advantage in suppressing the deterioration of the cell performance.

  Moreover, in the fuel cell 10A, as described above, since it is possible to deal with a problem with respect to the external force input from the left and right directions in FIG. 7, for example, the degree of freedom when the fuel cell 10A is mounted on the vehicle increases, and the vehicle The above advantages can be exhibited not only for external force input from the front but also for external force input from the rear of the vehicle.

  Next, another embodiment will be described. FIG. 8 is an explanatory diagram schematically illustrating the configuration of a fuel cell 10B of another embodiment and the behavior when an external force is input. This embodiment is characterized in that the fastening force is increased by bending the fuel cell stack when an external force is input.

  As shown in the figure, the fuel cell 10B does not change in that the fuel cell stack in which a plurality of fuel cells 100 are stacked is constrained by the upper and lower fixing plates in the figure, as in the fuel cell 10 described above. . The fuel cell 10B includes an end plate 151 on one end side of the fuel cell stack that is fitted and fixed to the first fixing plate 121, and includes a second fixing plate 120B outside the end plate 152 on the other end side. . The first fixing plate 121 and the second fixing plate 120B located at both ends of the fuel cell stack are fixed by a reinforcing material (not shown) so that the plate interval and the facing position do not change.

  The second fixed plate 120 </ b> B includes a recess facing the end plate 152, and the recess is a curved surface 122 </ b> Q that is curved so that the degree of the recess increases toward the center of the end plate 152. Since the second fixed plate 120B has a so-called arch shape, the curved surface 122Q is curved in the left-right direction in the figure, but is not curved from the front side to the back side in the figure.

  The fuel cell 10B includes a rolling roller 112 interposed between the end plate 152 and the second fixed plate 120B, and the rolling roller 112 can roll on the curved surface 122Q of the second fixed plate 120B. ing. Note that both ends of the curved surface 122Q are curved end surfaces 122QE whose degree of curvature is increased, and the rolling roller 112 is prevented from coming off by the curved end surfaces 122QE.

  In the fuel cell 10B of this embodiment, as shown in FIG. 8A, the initial position is when the fuel cell stack is located at the center of the curved surface 122Q. At this time, each fuel cell 100 is The interval between the first fixed plate 121 and the second fixed plate 120B and the degree of bending of the curved surface 122Q are defined so as to receive the initial fastening force. In addition, since the rolling roller 112 of the end plate 152 can roll on the curved surface 122Q, as shown in FIG. 8B, when an external force R is applied from the right side in the drawing, the rolling roller 112 rolls. The roller 112 rolls on the curved surface 122Q to shift the engagement state between the end plate 152 and the second fixed plate 120B, and deflects the fuel cell stack between the first fixed plate 121 and the second fixed plate 120B. . In this case, on the side where the distance between the end plate 152 and the end plate 151 is reduced due to the bending, the fastening force increases as shown in the figure. Therefore, as in the above-described embodiment, the fuel due to the temporary increase of the fastening force when the external force is input. It is possible to achieve both the suppression of inconveniences such as misalignment of each fuel battery cell 100 in the battery stack and the suppression of battery performance degradation. In this embodiment, the rolling of the rolling roller 112 can suppress the above-described problem and the battery performance even when an external force L is applied from the left side in FIG. 8B.

  Further, this fuel cell 10B can cope with a problem with respect to the external force input from the left and right direction in FIG. 8 similarly to the fuel cell 10A, so that the degree of freedom of mounting on the vehicle and the external force input from the front and rear direction of the vehicle are improved. However, the above advantages can be exhibited.

  As mentioned above, although the embodiment of the present invention has been described in the embodiments, the present invention is not limited to the above-described embodiments and modifications, and can be implemented in various modes without departing from the gist thereof. Is possible. For example, the curved surface 122Q included in the second fixed plate 120B shown in FIG. 8 may be a spherical surface. That is, the second fixed plate 120B has a spherical dome shape. In this case, the rolling roller 112 shown in FIG. 8 may be a rolling roller having an arbitrary trackball-like rolling direction. Thus, if the curved surface 122Q is a spherical surface, the input direction of the external force applied across the cell stacking direction is any direction, and the fuel cell stack is arranged in the first fixed plate in accordance with the input direction. It can bend between 121 and the 2nd fixed plate 120B, and the above-mentioned fastening force increase by this bending can be brought about. Therefore, in this case, the versatility in the input direction of the external force applied across the cell stacking direction is further increased, so that the degree of freedom for mounting on the vehicle is further increased, which is preferable.

  In addition, a separate fastening mechanism is provided to apply a fastening force (appropriate fastening force) for obtaining an appropriate cell surface pressure to the end plates at both ends of the fuel cell. It is also possible to exert a fastening force of.

  In addition, instead of the rolling roller 112, a leg that slides along the inclined surface 122S may be provided on the end plate 110. In this case, a slider structure may be adopted, a rail may be provided on the end plate, and the leg may be a piece that engages with the rail.

1 is an explanatory diagram schematically showing an overall configuration of a fuel cell 10 as an embodiment of the present invention. FIG. FIG. 3 is an explanatory view showing the periphery of a fixed plate 120 and an end plate 110 that are main parts of the fuel cell 10. FIG. 2 is an explanatory view showing a state of the fuel cell 10 in a stationary state with a part broken away. It is explanatory drawing which shows a partially broken behavior of the fuel cell 10 when an external force is applied across the cell stacking direction. It is explanatory drawing which shows roughly the whole structure of 10 A of fuel cells as another Example. It is explanatory drawing which shows the fixed plate 120A which is the principal part of 10 A of fuel cells, seeing through the end plate 110A. It is explanatory drawing which partially fractures and shows the mode of 10 A of fuel cells when there is no input of external force. It is explanatory drawing which illustrates roughly the structure at the time of external force input, and the structure of the fuel cell 10B of another Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 10A ... Fuel cell 10B ... Fuel cell 100 ... Fuel cell 102 ... Current collecting plate 110 ... End plate 110A ... End plate 110RB ... 1st bottom part 110LB ... 2nd bottom part 112 ... Rolling roller 120 ... Fixed plate 120A ... fixed plate 121 ... first fixed plate 120B ... second fixed plate 122Q ... curved surface 122S ... inclined surface 122QE ... curved end surface 122LS ... inclined surface 122RS ... inclined surface 124 ... raised portion 130 ... spring member 140 ... reinforcing material 151 ... end Plate 152 ... End plate

Claims (6)

A fuel cell in which a plurality of fuel cells are stacked between end plates,
In order to maintain the stacked state of the fuel cells, the end plate is restrained along the stack direction of the fuel cells, and an initial fastening force along the stack direction is applied to the fuel cells via the end plate. With a fastening force applying mechanism to be applied to
The fastening force applying mechanism is:
When an external force is applied to the fuel cell from a direction intersecting the stacking direction, a fastening force larger than the initial fastening force when there is no external force is applied to the fuel cell via the end plate. The fuel cell according to claim 1,
The fastening force applying mechanism is
A pair of fixed plates located outside the end plate, the fixed plate having a fixed interval between the plates;
An engagement member that is interposed between the fixed plate and the end plate, engages the fixed plate and the end plate, and transmits the initial fastening force from the fixed plate to the end plate;
The engaging member is
When the external force is applied, the fastening plate and the end plate are displaced into an engaged state, thereby transmitting a fastening force larger than the initial fastening force from the fixed plate to the end plate. The fuel cell according to claim 2, wherein
The pair of fixing plates is
The side facing the end plate is an inclined surface inclined with respect to the stacking direction, and the inclined surface is opposed so that the interval is wide at one end side of the end plate and the interval is narrowed at the other end side,
The engaging member is
The opposed inclined surfaces remain in a state where the end plates and the fuel cells between the end plates are stacked by interposing between the end plates and the fixed plate and causing movement along the inclined surfaces. The initial fastening force is transmitted from the fixed plate to the end plate when the end plate in the stacked state and the fuel cell are positioned on the wide side of the opposed inclined surface. Then, when the external force is applied, the end plate and the fuel cell in the stacked state cause movement along the inclined surface such that the opposed inclined surface moves to the narrower side. The fuel cell according to claim 3, wherein
Each of the pair of fixed plates includes the inclined surface as two inclined surfaces having opposite directions of inclination,
The engagement member is interposed between the end plate and the fixed plate so as to cause movement along the inclined surfaces in the two inclined surfaces having opposite directions of inclination. The fuel cell according to claim 2, wherein
The pair of fixing plates is
A first fixed plate fixed to one of the end plates, and a second fixed plate positioned on the other end plate side and facing the end plate and having a concave curved surface toward the center of the plate Prepared,
The engaging member is
By interposing between the second fixed plate and the other end plate and causing movement along the curved surface, the first end plate and the fuel cells between the end plates are stacked in the first state. When the end plate and the fuel cell in the stacked state are bent between the fixed plate and the second fixed plate and the fuel cell is positioned at the center of the curved surface, the initial fastening force is transferred from the second fixed plate to the end plate. When the external force is applied, the end plate and the fuel cell in the stacked state cause movement along the curved surface so as to bend from the center of the curved surface.   The fuel cell according to claim 5, wherein the curved surface is a spherical surface.

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