JP5765252B2 - Manufacturing method of fuel cell - Google Patents

Description

  The present invention relates to a fuel cell in which a fuel cell stack is fastened using a fastening member.

  As a method for fastening a fuel cell stack formed by stacking a plurality of fuel cells with a predetermined load, for example, a technique disclosed in Patent Document 1 below is known. This is a technology for adjusting the load in the stacking direction applied to the fuel cell stack by adjusting the amount of protrusion of a plurality of load adjusting screws provided on the fastening member after the fuel cell stack is fastened using the fastening member. is there.

  However, this technique adjusts the protruding amount of the plurality of load adjustment screws so that the load is uniformly applied in the surface direction of the laminated surface of each fuel cell after fastening, while setting the fastening load to a specified value. It was difficult.

JP 2008-159414 A

  The present invention has been made to solve the above-described conventional problems, and an object thereof is to provide a technique capable of appropriately fastening a fuel cell stack.

In order to solve at least a part of the problems described above, the present invention can take the following forms or application examples. One aspect of the present invention is a method of manufacturing a fuel cell, the step of preparing a fuel cell stack including a stacked body in which a plurality of fuel cells are stacked; and sandwiching both ends in the stacking direction of the fuel cell stack; A step of preparing a fastening member capable of fastening the fuel cell stack while maintaining a state in which a fastening load is applied in a direction; a step of determining a value of the fastening load after the fastening and setting as a specified load; and the fuel cell Applying a load equal to the specified load in the stacking direction in the stack to obtain a load stack length that is a length of the fuel cell stack in the stacking direction; and applying the fastening load in the fastening member A load equal to the length in the stacking direction of the fastening member is applied by applying a load equal to the specified load to the direction of the reaction force received from the fuel cell stack by the fastening. Obtaining a member length; obtaining a difference between the load stack length and the load fastening member length; and a plurality of load adjusting screws provided on a surface of the fastening member sandwiching the fuel cell stack. Adjusting each protruding amount to a length corresponding to the difference so that each of the plurality of load adjusting screws contacts the surface of the fuel cell stack; and after adjusting the protruding amount, the fastening member Fastening the fuel cell stack with the specified load using In such a configuration, the fuel cell stack is fastened after adjusting the amount of protrusion of the load adjustment screw before fastening, so the fastening load can be adjusted by individually adjusting the amount of protrusion of the plurality of load adjustment screws after fastening. As compared with the case where the adjustment is performed, the fastening can be performed while maintaining a state in which a load is uniformly applied to the stacked surface of the fuel cells after the fastening. In addition, the present invention can also be realized as the following forms.

[Application Example 1]
A method of manufacturing a fuel cell, the step of preparing a fuel cell stack including a stacked body in which a plurality of fuel cells are stacked, and sandwiching both ends in the stacking direction of the fuel cell stack, and applying a fastening load in the stacking direction A step of preparing a fastening member capable of fastening the fuel cell stack while maintaining the state, a step of determining a fastening load value after the fastening and setting it as a specified load, and in the fuel cell stack, in the stacking direction. Applying a load equal to the specified load to obtain a load stack length that is a length of the fuel cell stack in the stacking direction; and in the fastening member, the fuel cell by the fastening with the fastening load applied A load equal to the specified load is applied in the direction of the reaction force received from the stack to obtain a load fastening member length that is the length of the fastening member in the stacking direction. A step of obtaining a difference between the load stack length and the load fastening member length, and a projecting amount of each of a plurality of load adjusting screws provided on a surface of the fastening member sandwiching the fuel cell stack. A method of manufacturing a fuel cell, comprising: adjusting the length corresponding to the difference; and, after adjusting the amount of protrusion, fastening the fuel cell stack with the specified load using the fastening member.

  According to this method of manufacturing a fuel cell, the fuel cell stack is fastened after adjusting the amount of protrusion of the load adjustment screw before fastening. Therefore, the amount of protrusion of the plurality of load adjustment screws can be adjusted individually after fastening. As compared with the case where the load is adjusted, it is possible to perform the fastening while maintaining a state in which the load is uniformly applied to the stacked surface of the previous fuel cell after the fastening. Here, the load stack length refers to the distance between the contact surfaces at both ends in the stacking direction in contact with the fastening member by clamping by the fastening member.

  Note that the present invention can be realized in various modes. For example, it can be realized in the form of a fuel cell stack fastening method, a fuel cell system, or the like.

2 is an explanatory diagram showing a configuration of a fuel cell 10. FIG. It is explanatory drawing explaining the flow of a fastening process.

A. First embodiment:
(A1) Fuel cell structure:
FIG. 1 is an explanatory view showing the structure of a fuel cell 10 manufactured as an embodiment of the present invention. The fuel cell 10 is a solid polymer fuel cell. The fuel cell 10 includes a fuel cell stack 18 in which a stacked body in which a plurality of fuel cells 12 are stacked is sandwiched between a pressure plate 14 and an end plate 16. Further, the fuel cell 10 includes a stack case 22 having a U-shaped cross section as a fastening member for fastening the fuel cell stack 18. The fuel cell stack 18 is fastened by an end plate 16 that is a part of the stack cases 22 and 18 in a state where a predetermined load is applied in the stacking direction of the fuel cells 12 (hereinafter also simply referred to as stacking direction). ing. As shown in the drawing, the end plate 16 which is a part of the fuel cell stack 18 and the stack case 22 are fastened by being fixed by four fastening bolts 26.

  The stack case 22 is provided with eight through screw holes on the surface in contact with the pressure plate 14, and a load for adjusting a load in the stacking direction (hereinafter also referred to as a fastening load) applied to the fuel cell stack 18. Eight adjustment screws 30 are inserted. The load adjusting screw 30 protrudes from the stack case 22 toward the pressure plate 14 and presses the pressure plate 14. The protruding length of the load adjusting screw 30 (hereinafter, also referred to as the protruding amount) can be adjusted by tightening or loosening due to the rotation of the load adjusting screw 30. The fastening load is adjusted by adjusting the protruding amount of the load adjusting screw 30.

(A2) Fastening process:
Next, as a method for manufacturing the fuel cell 10, a step of fastening the fuel cell stack 18 by the end plate 16 and the stack case 22 (hereinafter also referred to as a fastening step) will be described. In the fastening process in the present embodiment, a prescribed fastening load (hereinafter also referred to as a prescribed load) is applied, and fastening is performed so that the applied fastening load is uniformly applied in the surface direction of the stacked surface of each fuel cell 12. It is processing.

  FIG. 2 is an explanatory view illustrating the flow of the fastening process. As a first step in the fastening step, an expected value of the length in the stacking direction of the fuel cell stack 18 after fastening is obtained when the fuel cell stack 18 is fastened with a specified load. Specifically, as shown in the first step of FIG. 2, in order to apply a specified load in the stacking direction to the fuel cell stack 18, a pressure cylinder SL1 including a load cell LD1 for measuring the load is prepared. The displacement meter MS1 is installed in the fuel cell stack 18 in order to measure the displacement of the length in the stacking direction of the fuel cell stack 18 before and after applying the load. In this embodiment, a laser measuring meter is used as the displacement meter MS1. Thereafter, the fuel cell stack 18 is installed in the pressure cylinder SL1. Further, in order to apply a specified load to the fuel cell stack 18 in a state close to the state fastened by the stack case 22, when the fuel cell stack 18 is installed in the pressure cylinder SL1, the pressure plate 14 and the pressure cylinder SL1 are pressed. Between the surfaces, a cylindrical metal piece MT having the same diameter as the load adjusting screw 30 is installed.

  After the fuel cell stack 18 is installed in the pressure cylinder SL1 in this way, a specified load in the stacking direction is applied to the fuel cell stack 18 by the pressure cylinder SL1 while measuring the load with the load cell LD1. In this embodiment, the specified load is 40 [KN]. When a load is applied to the fuel cell stack 18, each member constituting the fuel cell stack 18 is distorted, and the length in the stacking direction is shortened. Thereafter, the displacement of the length in the stacking direction of the fuel cell stack 18 is measured by the displacement meter MS1 in a state where the specified load is applied. After the displacement measurement, the length in the stacking direction of the fuel cell stack 18 in a state where a specified load is applied (hereinafter, referred to as a difference between the known length of the fuel cell stack 18 such as a master gauge and the measured displacement) (Also referred to as load stack length P) is calculated, and the load stack length P is set as an expected value of the length in the stacking direction of the fuel cell stack 18 after fastening. Further, in the present embodiment, the load stack length P is, as shown in the figure, from the contact surface of the end plate 16 with the fuel cell 12 in a state where a specified load is applied to the fuel cell stack 18 to the pressure plate 14. The length in the stacking direction up to the surface facing the stack case 22 is said.

  After obtaining the load stack length P in the first step, as a second step in the fastening step, the stack case 22 in the stacking direction of the stack case 22 when the fuel cell stack 18 is fastened with the specified load using the stack case 22 is used. Get the expected length. Specifically, as shown in the second step of FIG. 2, a specified load is applied to the stack case 22 in the direction of the reaction force against the fastening load received from the fuel cell stack 18 by fastening (hereinafter also referred to as the reaction force direction). For this purpose, a pressure cylinder SL2 including a load cell LD2 for measuring a load is prepared. The displacement meter MS2 is installed in the stack case 22 in order to measure the displacement of the stack case 22 in the stacking direction. In this embodiment, a laser measuring meter is used as the displacement meter MS2. Thereafter, the stack case 22 is installed in the pressure cylinder SL2. Further, in order to apply a specified load to the stack case 22 in a state close to the state in which the fuel cell stack 18 is fastened, the eight load adjustment screws 30 included in the stack case 22 are protruded by a predetermined length equal to each other. To do.

  After the stack case 22 is installed in the pressure cylinder SL2 in this way, a specified load in the reaction force direction is applied to the stack case 22 by the pressure cylinder SL2 while measuring the load with the load cell LD2. In the present embodiment, the specified load is 40 [KN] as in the first step. The stack case 22 is distorted by applying a load, and the length in the stacking direction is increased. And the displacement of the length of the stacking direction of the stack case 22 is measured by the displacement meter MS2 in a state where the specified load is applied. Thereafter, the length of the stack case 22 in a state where a specified load is applied (hereinafter also referred to as a load fastening member length Q) based on the difference between the known length in the stacking direction of the stack case 22 such as a master gauge and the measured displacement. ) And the load fastening member length Q is set as an expected value of the length in the stacking direction of the stack case 22 after fastening. Further, in the present embodiment, the load fastening member length Q is, as shown in the figure, a lamination from a surface facing the pressure plate 14 to a contact surface with the end plate 16 when a specified load is applied to the stack case 22. Say the length of the direction.

  As a third step in the fastening step, the load adjusting screw 30 is pushed out in the stack case 22 before fastening. The protruding amount of the load adjusting screw 30 is set to a difference R (= Q−P) between the load stack length P and the load fastening member length Q. Specifically, a load adjusting screw 30 corresponding to the difference R is used by using a calculation device (hereinafter also referred to as a rotation number calculation device) that performs a calculation using a function that represents the relationship between the rotation speed and the protruding amount of the load adjustment screw 30. The number of rotations is calculated. Then, each of the eight load adjustment screws 30 that the stack case 22 actually has is rotated by the calculated number of rotations, and the protrusion of the difference R is realized from the contact surface of the stack case 22 with the pressure plate 14. By doing so, the protruding amounts of the eight load adjusting screws 30 are equal to each other. For convenience of explanation, the load stack length P and the load fastening member length Q are acquired from the first step to the third step, and the difference R is calculated from the acquired load stack length P and the load fastening member length Q. Although it has been described that the rotation speed is calculated, actually, the rotation speed calculation device calculates the difference R using the displacement of the fuel cell stack 18 acquired in the first process and the displacement of the stack case 22 acquired in the second process. Calculate and output the number of rotations of the load adjusting screw 30.

  In the third step, the load adjustment screw 30 with the difference R is projected. However, in the second step, the load adjustment screw 30 is projected in advance by a predetermined amount, so the third step. In step 2, the adjustment amount of the load adjusting screw 30 may be adjusted by calculating the amount of protrusion adjusted from the predetermined amount of protrusion in the second step.

  After projecting the load adjusting screw 30 in the third step, as a fourth step in the fastening step, the fuel cell stack 18 is sandwiched between the stack case 22 and the pressing plate 28 that is a pressing jig, and in the stacking direction. The fuel cell stack 18 is fastened while applying a load. Specifically, a separate pressurizing cylinder is prepared (not shown), and the stack case 22 and the pressing plate 28 that sandwich the fuel cell stack 18 are pressed. As described with reference to FIG. 16 is fixed with a fastening bolt 26. In this embodiment, a load cell is installed in the pressure cylinder used for fastening, and the fastening load is obtained from the relationship between the pressure applied by the pressure cylinder and the pressure when releasing the pressure after fastening. Then, it is confirmed that the fastening load of the fuel cell stack 18 is the specified load (40 [KN]). In this way, the fuel cell stack 18 is fastened using the stack case 22 and the end plate 16, and the fastening process is completed.

  As described above, when the fuel cell 10 is manufactured by employing the fastening process described in this embodiment, the protruding amounts of the eight load adjusting screws 30 are set to be equal before fastening, and then fastening is performed. The eight load adjustment screws 30 each press the pressure plate 14 with an equal load. Therefore, the fuel cell stack 18 can be fastened in a state where the fastening load is uniformly applied in the surface direction of the stacked surface of the fuel battery cells 12. That is, the phenomenon that at least one of the eight load adjusting screws 30 does not press the pressure plate 14 can be avoided. Further, the amount of protrusion of the load adjusting screw 30 can be easily adjusted as compared with the case where the amount of protrusion of each load adjusting screw 30 is individually adjusted so that each load adjusting screw 30 presses the pressure plate 14 evenly after fastening. Can be concluded. Furthermore, in the fastening process in the present embodiment, the amount of protrusion of the load adjusting screw 30 is set in advance so that the fastening load becomes the specified load in consideration of the distortion of the fuel cell stack 18 and the stack case 22. The value of the fastening load applied to the fuel cell stack 18 after fastening can be accurately set to the specified load.

  In this embodiment, the rotation speed of the load adjustment screw 30 is calculated using the rotation speed calculation device, and the amount of protrusion of the load adjustment screw 30 is set, so that the fastening load can be accurately set to the specified load. . In addition, as described above, it is possible to confirm whether the fastening load is the specified load by installing a load cell in the pressure cylinder used at the time of fastening. Can do.

B. Variation:
The present invention is not limited to the above-described examples and embodiments, and can be carried out in various modes without departing from the gist thereof. For example, the following modifications are possible.
(B1) Modification 1:
In the above embodiment, in the stack case 22, the screw hole for installing the load adjusting screw 30 is a through-hole penetrating from the contact surface with the pressure plate 14 toward the outside, but is recessed from the contact surface. It is good also as a bottomed hole provided in. By doing in this way, the lid | cover and resin which block | close the recessed part made outside the stack case 22 after performing the protrusion of the load adjustment screw 30 can be made unnecessary.

(B2) Modification 2:
In the above-described embodiment, the load adjusting screw 30 is described as eight. However, the load adjusting screw 30 may adopt any number within the range in which the load adjusting screw 30 can be installed in the stack case 22, whether it is eight or more. it can. Even if it does in this way, the effect similar to the said Example can be acquired. Further, when the stack case 22 including four or more load adjusting screws 30 is employed, a phenomenon that at least one of the load adjusting screws 30 does not press the pressure plate 14 can be avoided.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 12 ... Fuel cell 14 ... Pressure plate 16 ... End plate 18 ... Fuel cell stack 22 ... Stack case 26 ... Fastening bolt 28 ... Pressing plate 30 ... Load adjustment screw P ... Load stack length Q ... Load fastening member length R ... Difference MT ... Metal piece LD1, LD2 ... Load cell SL1, SL2 ... Pressure cylinder MS1, MS2 ... Displacement meter

Claims (1)

A fuel cell manufacturing method comprising:
Preparing a fuel cell stack comprising a laminate in which a plurality of fuel cells are laminated;
Preparing a fastening member that sandwiches both ends of the fuel cell stack in the stacking direction and holds the state in which a fastening load is applied in the stacking direction and can fasten the fuel cell stack;
Determining the value of the fastening load after the fastening and setting as a specified load;
In the fuel cell stack, applying a load equal to the specified load in the stacking direction to obtain a load stack length that is the length of the fuel cell stack in the stacking direction;
In the fastening member, a load that is a length in the stacking direction of the fastening member by applying a load equal to the specified load in a direction of a reaction force received from the fuel cell stack by the fastening with the fastening load applied. Obtaining a fastening member length;
Obtaining a difference between the load stack length and the load fastening member length;
In the fastening member, the amount of protrusion of each of the plurality of load adjustment screws provided on the surface sandwiching the fuel cell stack is set such that each of the plurality of load adjustment screws contacts the surface of the fuel cell stack. Adjusting to a length corresponding to the difference;
And a step of fastening the fuel cell stack with the specified load using the fastening member after the adjustment of the protruding amount.

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