JP2010010049A - Detector and fuel cell unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the measuring accuracy of a fastening load on a fuel cell stack. <P>SOLUTION: A fuel cell unit includes the fuel cell stack wherein a laminated body including a membrane-electrode conjugant is held by a pair of pushing plates, a fixing member for fixing the fuel cell stack on a mounted section where the fuel cell stack is mounted, and a detector arranged on the fixing member and detecting a strain of the fixing member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a detector for detecting distortion and a fuel cell unit.

  Conventionally, a fuel cell stack in which a plurality of unit cells including a membrane electrode assembly are stacked is known. A predetermined fastening load is applied to the fuel cell stack in the stacking direction by a pressing member such as an end plate in order to reduce the contact resistance between the constituent members. If the fuel cell stack is continuously operated, the applied load is changed due to the thermal expansion of the constituent members and the swelling of the electrolyte membrane, and the power generation efficiency decreases due to non-uniform surface pressure in the power generation region. There was a fear. Therefore, grasping the state of the fastening load is important for suppressing the decrease in power generation efficiency, and as a method for measuring the fastening load, a measurement method using distortion of the constituent members of the fuel cell stack is known. ing. (Patent Document 1).

JP 2004-127809 A JP 2001-325985 A

  However, when the fastening load is measured based on the distortion of the constituent members of the fuel cell stack, the distortion of the constituent members is not only due to the change in the fastening load, but also due to the temperature change of the constituent members due to heat generation. As a result, the measurement accuracy of the fastening load may be reduced.

  The present invention has been made to solve at least a part of the above-described conventional problems, and an object thereof is to improve the measurement accuracy of the fastening load in the fuel cell stack.

  In order to solve at least a part of the above problems, the present invention employs the following aspects.

  A first aspect of the present invention provides a detector that detects distortion. The detector according to the first aspect of the present invention is disposed on a fixing member that fixes a fuel cell stack formed by sandwiching a laminated body including a membrane electrode assembly between a pair of pressing plates.

  According to the detector according to the first aspect of the present invention, since the detector is disposed on the fixing member that fixes the fuel cell stack, the distortion in which the influence of the distortion due to the temperature difference in the component member is suppressed is detected. And the measurement accuracy of the fastening load can be improved.

  A second aspect of the present invention provides a fuel cell unit. A fuel cell unit according to a second aspect of the present invention includes a fuel cell stack in which a laminate including a membrane electrode assembly is sandwiched between a pair of pressing plates, and an installation portion where the fuel cell stack is installed. A fixing member that fixes the fuel cell stack; and a detector that is disposed on the fixing member and detects distortion of the fixing member.

  According to the fuel cell unit according to the second aspect of the present invention, since the detector is disposed on the fixed member, it is possible to output a strain in which the influence of the strain due to the temperature difference in the component member is suppressed. The fastening load measurement accuracy can be improved.

  In the fuel cell unit according to the second aspect of the present invention, the fixing member may be connected to an outer peripheral portion of the pressing plate. In this case, the influence of the strain caused by the temperature difference in the component member is suppressed, and the distortion reflecting the influence of the strain caused by the fastening load of the fuel cell stack can be output well. Accuracy can be improved.

  In the fuel cell unit according to the second aspect of the present invention, the fixing member includes a first fastening member that connects the pressing plate and the fixing member, and the detector is connected to the first fastening member. It may be installed. In this case, the fastening load can be measured satisfactorily by outputting the strain of the first fastening member.

  In the fuel cell unit according to the second aspect of the present invention, the fixing member includes a second fastening member that connects the installed portion and the fixing member, and the detector includes the second fastening member. It may be installed in. In this case, the fastening load can be measured satisfactorily by outputting the distortion of the second fastening member.

  In the fuel cell unit according to the second aspect of the present invention, the detector may be a strain gauge, and the strain gauge may be installed at a position facing each other with the fixing material interposed therebetween. In this case, it is possible to improve the detection accuracy of the distortion of the fixing member and to measure the fastening load satisfactorily.

  The present invention can be realized in various forms. For example, the present invention can be realized in the form of a fuel cell system including a fuel cell unit, a moving body on which the fuel cell system is mounted, and the like. It can be applied by omitting a part.

  Hereinafter, a fuel cell according to the present invention will be described based on examples with reference to the drawings.

A. First Example A1. Fuel cell unit configuration:
FIG. 1 is an explanatory diagram illustrating a schematic configuration of a fuel cell unit according to a first embodiment of the invention. The fuel cell unit 10 according to this embodiment includes a fuel cell stack 100, a fuel cell case 150, a mount portion 160, and a strain gauge 200. The fuel cell unit 10 is mounted on, for example, a fuel cell vehicle and is used as a unit that supplies electric power to the fuel cell vehicle.

  The fuel cell stack 100 constitutes a solid polymer type fuel cell that receives supply of hydrogen and air and generates electric power through an electrochemical reaction. The fuel cell stack 100 includes a stacked body 110, an end plate 130, a fastening bolt 140, and a tension shaft 145. In this embodiment, the fuel cell stack 100 is a solid polymer fuel cell, but may be a fuel cell other than this.

  The stacked body 110 has a configuration in which a plurality of fuel cells 120 are stacked. The fuel cell 120 includes MEA (Membrane-Electrode Assembly) in which catalyst layers 122 functioning as an anode and a cathode are disposed on both surfaces of the electrolyte membrane 121, and diffusion disposed on both sides of the MEA. The layer 123 and the separators 124 disposed on both sides of the diffusion layer 123 are formed.

  The electrolyte membrane 121 is formed of a polymer electrolyte membrane made of a fluorine resin. The catalyst layer 122 is formed of a carbon carrier carrying platinum and a platinum alloy as a catalyst. The diffusion layer 123 is made of carbon paper. The separator 124 is a conductive member that collects electricity generated in the MEA, and can be formed of a thin plate made of stainless steel, for example. The configuration of the fuel battery cell 120 is not limited to this, and may be different from this. Moreover, the laminated body 110 may laminate | stack two or more types of fuel battery cells 120 from which a structure differs.

  The end plates 130 are respectively disposed at both ends of the stack 110 of the fuel cells 120 in the stack 110 (hereinafter simply referred to as “stacking direction”) via insulators 125 and terminal plates 126. When the end plate 130 is abutted with the laminate 110, a flange portion 132 that does not contact the laminate 110 is formed in the vicinity of the outer peripheral portion.

  Between the flange portions 132 of the end plates 130 disposed at both ends of the laminated body 110, tension shafts 145 are disposed along the laminating direction. Both ends of the tension shaft 145 are screwed together by fastening bolts 140 penetrating the flange portion 132. By tightening the fastening bolt 140, the end plate 130 presses the laminated body 110 from both sides and sandwiches the laminated body 110 in a state where a predetermined fastening load is applied in the laminating direction.

  The fuel cell case 150 has a substantially bowl shape and stores the fuel cell stack 100 therein. In the present embodiment, the fuel cell case 150 has a configuration in which an installation portion (bottom surface) for installing the fuel cell stack 100 and a covering portion (side surface, top surface) covering the fuel cell stack 100 are integrated. You may comprise as a separate member. The fuel cell case 150 can be formed of resin, metal, or the like.

  The mount part 160 is configured by a combination of a metal such as stainless steel or an insulating elastic body such as rubber. The mount unit 160 is a gantry member that is disposed under the end plates 130 disposed at both ends of the stacked body 110 and supports the fuel cell stack 100. The mount portion 160 is a fixing member that fixes the fuel cell stack 100 to the fuel cell case 150 by connecting to the flange portion 132, and insulates the fuel cell stack 100 from the fuel cell case 150. The configuration of the mount unit 160 will be described in detail later. The mount portion 160 corresponds to a “fixing member” in the claims.

  The strain gauge 200 is a thin plate sensor and is disposed on the mount unit 160. The arrangement position in the mount unit 160 will be described later. The strain gauge 200 is deformed following the strain generated in the mount portion 160 when the strain gauge 200 is attached to the mount portion 160, and the internal resistance value is changed by the deformation. By applying a voltage from the conductive wire 201 connected to the strain gauge 200 to the strain gauge 200, the change in the resistance value can be detected, and the strain amount of the mount unit 160 can be measured based on the output value.

  The dynamic strain measurement circuit 210 is connected to the strain gauge 200 and is a circuit that measures the strain amount of the mount unit 160 from the output value of the strain gauge 200. As the dynamic strain measuring circuit 210, a commercially available dynamic strain measuring device can be used.

  The axial force calculation circuit 220 is connected to the dynamic strain measurement circuit 210 and measures the fastening load of the fuel cell stack 100 from the strain amount of the mount unit 160 output from the dynamic strain measurement circuit 210. The axial force calculation circuit 220 may be configured to be connected to a temperature sensor that measures the temperature of the tension shaft 145 or the laminated body 110 and to input temperature information for the temperature correction for the strain amount. In the present embodiment, the dynamic strain measurement circuit 210 and the axial force calculation circuit 220 are illustrated as different configurations from the fuel cell unit 10, but may be configured as a part of the fuel cell unit 10.

A2. Mount configuration:
FIG. 2 is an explanatory view illustrating a cross-sectional configuration of the mount portion. As shown in FIG. 2, the mount unit 160 includes a first mount member 161, a second mount member 162, a third mount member 163, a fourth mount member 164, an end plate fixing bolt 165, and a mount fixing bolt. 166. In the present embodiment, the first mount member 161 and the third mount member 163 are made of metal, and the second mount member 162 and the fourth mount member 164 are made of insulating elastic bodies. It may be constituted by. The first mount member 161, the second mount member 162, the third mount member 163, and the fourth mount member 164 are stacked in order, and the first mount member 161 contacts the end surface formed on the flange portion 132 of the end plate 130. The fourth mount member 164 is in contact with the portion where the fuel cell case 150 is installed.

  The first mount member 161, the second mount member 162, and the third mount member 163 each have a hollow portion that communicates by being stacked. The end plate fixing bolt 165 passes through the hollow portion, and the tip portion is screwed to the end plate 130. As a result, the first mount member 161, the second mount member 162, and the third mount member 163 are fixed to the end plate 130. The end plate fixing bolt 165 corresponds to the “first fastening member” in the claims.

  Similarly, the third mount member 163 and the fourth mount member 164 each have a hollow portion that communicates by being laminated. The mount fixing bolt 166 passes through this hollow portion, and the tip end portion is fastened with a nut on the third mount member 163. As a result, the third mount member 163 and the fourth mount member 164 are fixed to the fuel cell case 150. The mount fixing bolt 166 corresponds to the “second fastening member” in the claims.

  As described above, the fuel cell stack 100 is fixed to the fuel cell case 150. In the present embodiment, the mount fixing bolt 166 is used to fix the third mount member 163 and the fourth mount member 164 and the fuel cell case 150. Furthermore, the automobile in which the fuel cell case 150 is installed. The fuel cell case 150 and these may be fixed by penetrating through the side frame or the cross member passed to the side frame.

A3. Position of strain gauge:
Two strain gauges 200 are arranged on each of the end plate fixing bolt 165 and the mount fixing bolt 166. The two strain gauges 200 are arranged so as to face each other in the stacking direction via an end plate fixing bolt 165 and a mount fixing bolt 166, respectively. Of the two strain gauges 200 arranged on the end plate fixing bolt 165 and the mount fixing bolt 166, the one closer to the laminate 110 is called an inner strain gauge 200a, and the one far from the laminate 110 is called an outer strain gauge 200b. . The strain gauge 200 is disposed in a direction in which expansion and contraction in the axial direction of the end plate fixing bolt 165 and the mount fixing bolt 166 can be detected. In this embodiment, two strain gauges 200 are arranged on each of the end plate fixing bolt 165 and the mount fixing bolt 166, but the number of the strain gauges 200 is not limited to two, and the end plate fixing bolt 165 and The number of the mounting fixing bolts 166 may be different. Moreover, you may arrange | position only to either one of the end plate fixing bolt 165 and the mount fixing bolt 166.

A4. Fastening load measurement:
FIG. 3 is an explanatory view showing a state in which the mount portion is distorted. The electrolyte membrane 121 swells and increases its thickness by continuing power generation. Therefore, the stacked body 110 expands in the stacking direction, and the end plate 130 is curved toward the outside of the fuel cell stack 100 at the central portion that contacts the stacked body 110. At this time, the end plate fixing bolt 165 receives a stress F from the connected end plate 130 toward the outside of the fuel cell stack 100.

  When the stress F is received, in the cross section of the end plate fixing bolt 165, a tensile force is generated along the axial direction on the laminated body 110 side, and a compressive force is generated on the opposite side. Therefore, a strain due to tension is detected in the inner strain gauge 200a, and a strain due to compression is detected in the outer strain gauge 200b. In addition, the mounting fixing bolt 166 is also subjected to bending stress when the end plate fixing bolt 165 receives stress F. Like the end plate fixing bolt 165, the inner strain gauge 200a detects strain due to tension, and the outer strain gauge 200b. Then, distortion due to compression is detected.

Based on the strain amounts detected from the inner strain gauge 200a and the outer strain gauge 200b disposed on the end plate fixing bolt 165 and the mount fixing bolt 166, respectively, an axial force applied to the end plate fixing bolt 165 and the mount fixing bolt 166 ( The fastening load of the fuel cell stack 100 can be measured by canceling the tensile stress and the compressive stress.

A5. Heat transfer:
Since the fuel cell 120 becomes high temperature (for example, 100 ° C.) during power generation, the region closer to the stacked body 110 also becomes higher in the end plate 130. The heat generated from the laminated body 110 moves from the center portion of the end plate 130 to the flange portion 132 and is transmitted from the flange portion 132 to the end plate fixing bolt 165. The mount fixing bolt 166 is further transmitted via the third mount member 163 and the like. Therefore, the temperature change of the end plate fixing bolt 165 and the mount fixing bolt 166 is smaller than that of the end plate 130, and the distortion caused by the temperature change is smaller than that of the end plate 130.

  According to the strain gauge 200 according to the first embodiment described above, since the strain gauge 200 is disposed on the mount portion 160 that fixes the fuel cell stack 100, the strain in which the influence of the strain due to the temperature difference in the member is suppressed is suppressed. And the measurement accuracy of the fastening load of the fuel cell stack 100 can be improved. Specifically, the mount portion 160 is not easily affected by the heat generated by the fuel cell stack 100, and the influence of distortion due to the temperature difference is suppressed. Therefore, distortion caused by a change in the fastening load of the fuel cell stack 100 can be detected well, and the measurement accuracy of the fastening load of the fuel cell stack 100 can be improved.

  Further, since it is possible to detect a strain in which the influence of the strain due to the temperature difference in the member is suppressed, the fastening load of the fuel cell stack 100 can be measured without using a temperature correction sensor or the like. The apparatus for can be simplified.

  According to the fuel cell unit 10 according to the first embodiment, since the strain gauge 200 is disposed in the mount portion 160, it is possible to output the strain due to the change in the fastening load of the fuel cell stack 100 satisfactorily. The measurement accuracy of the fastening load can be improved. Specifically, the distortion due to the temperature difference is suppressed in the mount portion 160 during operation of the fuel cell. Therefore, the strain resulting from the change in the fastening load of the fuel cell stack 100 can be output satisfactorily by disposing the strain gauge 200 on the mount portion 160.

  According to the fuel cell unit 10 according to the first embodiment, since the mount portion 160 on which the strain gauge 200 is disposed is connected to the flange portion 132 of the end plate 130, a distance from the heat generating portion can be secured, By connecting to the end plates 130 disposed at both ends of the stacked body 110, distortion is favorably caused due to a change in the tightening load of the stacked body 110, so that the measurement accuracy of the fastening load of the fuel cell stack 100 is improved. be able to.

  According to the fuel cell unit 10 according to the first embodiment, since the strain gauge 200 is disposed on the end plate fixing bolt 165 or the mount fixing bolt 166, the fastening load can be measured satisfactorily. Specifically, the bolt has a comparatively small cross section and deforms well with the stress caused by the fastening load, so that it is easy to detect the distortion. Moreover, since it may arrange | position anywhere on the surface of a volt | bolt, it is hard to receive the restriction | limiting of the place and number of arrangement | positioning. Furthermore, since it sticks to the bolt for fixing the fuel cell stack 100, it is not necessary to prepare a new member for arranging the strain gauge 200.

  According to the fuel cell unit 10 according to the first embodiment, since the strain gauges 200 are respectively arranged at opposing positions via the end plate fixing bolt 165 or the mount fixing bolt 166, the fuel cell stack 100 can be satisfactorily used. The fastening load can be measured. Specifically, the axial force (tensile stress, compressive stress) applied to the end plate fixing bolt 165 and the mount fixing bolt 166 can be canceled based on the strain amounts detected from the two strain gauges 200.

B. Modifications Note that 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 implementations are also possible. .

B1. Modification 1:
FIG. 4 is an explanatory view illustrating a cross-sectional configuration of a mount portion according to a modification. In the first embodiment, the strain gauge 200 is disposed on the end plate fixing bolt 165 and the mount fixing bolt 166. However, if the strain gauge 200 is on the mount portion 160, for example, the first mount member 161, the fourth mount member 164, etc. You may arrange in. Even in this case, it is difficult to be affected by the heat generation of the fuel cell stack 100, and the influence of distortion due to the temperature difference is suppressed. Further, the influence of the expansion and contraction of the stacked body 110 can be satisfactorily received through the end plates 130 disposed at both ends of the stacked body 110, and the measurement accuracy of the fastening load of the fuel cell stack 100 can be improved.

B2. Modification 2:
In the first embodiment, the mount portion 160 is disposed below the end plate 130, but is not limited thereto, and may be disposed, for example, below the tension shaft 145. The mount unit 160 may be configured to include a lock mechanism or the like instead of one or both of the end plate fixing bolt 165 and the mount fixing bolt 166.

B3. Modification 3:
In the first embodiment, the mount unit 160 includes a first mount member 161, a second mount member 162, a third mount member 163, and a fourth mount member 164. The structure which is not provided may be sufficient, or the structure provided with another member may be sufficient. In addition, the number of mount portions 160 disposed under the end plate 130 is not particularly limited, and may be one or two for each end plate 130. The plate 130 may be connected.

B4. Modification 4
Although not described in the first embodiment, the fuel cell unit 10 further stores an electric actuator capable of controlling the fastening load and an appropriate value of the axial force set in advance corresponding to the fuel cell stack 100. And a function of comparing the measured fastening load with an appropriate value and controlling the fastening load to be a predetermined value by using an electric actuator. Thereby, for example, it is possible to suppress a decrease in power generation efficiency caused by nonuniform surface pressure in the power generation region.

B5. Modification 5
In the present embodiment, the fuel cell unit 10 has been described as an embodiment of the present invention. In addition, for example, a step of preparing the fuel cell stack 100 fixed to the mount portion 160 and a distortion in the mount portion 160 are described. A method for measuring the fastening load of the fuel cell stack 100 including a step of arranging the gauge 200 and a step of measuring the fastening load of the fuel cell stack 100 from the strain detected by the gauge 200, and measurement using this measurement method It can be realized as a device.

  As mentioned above, although the Example of this invention was described, it cannot be overemphasized that this invention is not limited to these Examples, and can take a various structure in the range which does not deviate from the meaning.

It is explanatory drawing which illustrated schematic structure of the fuel cell unit which concerns on 1st Example of this invention. It is explanatory drawing which illustrated the cross-sectional structure of the mount part. It is explanatory drawing which shows the state which distortion generate | occur | produced in the mount part. It is explanatory drawing which illustrated the cross-sectional structure of the mount part which concerns on a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell unit 100 ... Fuel cell stack 110 ... Laminated body 120 ... Fuel cell 130 ... End plate 132 ... Flange part 140 ... Fastening bolt 145 ... Tension shaft 150 ... Fuel cell case 160 ... Mount part 161 ... 1st mount member 162 ... 2nd mount member 163 ... 3rd mount member 164 ... 4th mount member 165 ... End plate fixing bolt 166 ... Mount fixing bolt 200 ... Strain gauge 201 ... Conductive wire 210 ... Dynamic strain measuring circuit 220 ... Axial force calculation circuit

Claims (7)

A detector for detecting distortion,
The detector arrange | positioned at the fixing member which fixes the fuel cell stack formed by pinching | stacking the laminated body containing a membrane electrode assembly with a pair of press plate. A fuel cell unit,
A fuel cell stack in which a laminate including a membrane electrode assembly is sandwiched between a pair of pressing plates;
A fixing member for fixing the fuel cell stack to an installation portion where the fuel cell stack is installed;
A fuel cell unit comprising: a detector that is disposed on the fixing member and detects distortion of the fixing member. The fuel cell unit according to claim 2, wherein
The fixing member is a fuel cell unit connected to an outer peripheral portion of the pressing plate. The fuel cell unit according to claim 3, wherein
The fixing member includes a first fastening member that connects the pressing plate and the fixing member,
The detector is a fuel cell unit installed on the first fastening member. In the fuel cell unit according to claim 3 or 4,
The fixing member includes a second fastening member that connects the portion to be installed and the fixing member,
The detector is a fuel cell unit installed on the second fastening member. The fuel cell unit according to any one of claims 2 to 5,
The detector is a strain gauge;
The said strain gauge is a fuel cell unit each installed in the position which opposes via the said fixing member. A method for measuring a fastening load of a fuel cell stack,
A step of preparing a fuel cell stack formed by sandwiching a laminate including a membrane electrode assembly by a pair of pressing plates and being fixed to an installation portion by a fixing member;
Arranging a detector for detecting distortion of the fixing member on the fixing member;
Measuring the fastening load of the fuel cell stack from the strain detected by the detector.

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