JP2005078970A - Fuel battery and fuel battery radiation heat utilization system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel battery and a fuel battery system using the fuel battery capable of effectively radiating the heat generated in a solid polymer fuel battery to outside with simple configuration. <P>SOLUTION: Each of a plurality of first heat pipes 4a is structured of a conductive pinched part 41 pinched between each two fuel battery cells 20 and a projection 42 protruded outside from the space between the adjacent fuel cells 20. The projection 42 is structured of a protruded root part 421 extended in the same direction as the conductive pinched part 41, and a folded part 422 extended in parallel with a side face 28 of a stack 2. In the conductive pinched parts 41, operating liquid inside the fuel cells 20 is boiled and evaporated by their radiation heat to move toward the folded parts 422 at a low-temperature end, and cooled at the folded part, and the radiation heat is transferred to second heat pipes 6 installed outside the stack 2, and transferred from the second heat pipes 6 to a heat exchanger 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell, for example, a fuel cell including a laminate in which a plurality of fuel cells using a solid polymer membrane as an electrolyte are stacked, and a fuel cell heat radiation utilization system utilizing heat radiation from the fuel cell. More particularly, the present invention relates to a fuel cell having an improved cooling structure for the fuel cell and a fuel cell heat radiation utilization system having an improved recovery mechanism for heat radiation from the fuel cell.

  In a conventional polymer electrolyte fuel cell, a cooling plate having a cooling medium flow path is arranged between a plurality of stacked fuel cells, and the cooling medium is circulated by a cooling water pump to recover waste heat generated by power generation. They are reused in heat exchangers. Further, from Patent Document 1 described later, a heat pipe in which a tubular pipe portion on the high temperature side is built in each of the conductive separator for fuel gas and the conductive separator for oxidant gas constituting the fuel cell is arranged, A technique is also known in which a heat radiating fin is provided at the other end of the heat pipe, and heat generated in the polymer electrolyte fuel cell is guided to the outside of the fuel cell through the heat pipe and radiated into the air.

By the way, in the conventional method for cooling a polymer electrolyte fuel cell using a cooling medium flow path, a pump for circulating the cooling medium and a pipe for feeding the cooling medium are required. Therefore, the fuel cell system is complicated and expensive. There was a problem of becoming something. Moreover, in the technique of patent document 1, it is necessary to incorporate the cylindrical pipe part used as the high temperature side of the said heat pipe in each separator, and to adhere. At this time, the laminated separators need to be in close contact with the adjacent separators without any gap, and there is a problem that the manufacturing cost becomes high in order to realize such a structure with a circular heat pipe.
JP 2000-353536 A (Claim 1, Claim 2, Paragraph 0017, FIG. 1)

  The present invention has been made to solve the above-described problems in the prior art, and is capable of effectively releasing heat generated in the fuel cell to the outside with a simple configuration. It is an object of the present invention to provide a fuel cell heat radiation utilization system using a fuel cell.

  According to a first aspect of the present invention, there is provided a fuel cell stack comprising: a plurality of fuel cell stacks; and a plate-like conductive sandwiched portion sandwiched between the fuel cells and an external portion between the fuel cells. And a first heat dissipating device for releasing heat generated in the fuel cell to the outside. The fuel cell according to claim 4 of the present invention is adjacent to the fuel cell. The ends of the protruding portions of the first heat radiating device protrude outward from the fuel cells in different directions so as not to contact each other, or are bent in opposite directions to each other. Furthermore, the fuel cell according to claim 5 of the present invention is characterized in that a second heat dissipating device is provided on the outer surface of the protruding portion bent through an electric insulating sheet.

  A fuel cell heat radiation utilization system according to claim 8 of the present invention includes a heat exchanger for exchanging heat from the fuel cell collected in the second heat radiation device of the fuel cell. It is.

  In the fuel cell of the present invention, since the first heat radiating device having a flat conductive sandwiched portion sandwiched between the fuel cells is adopted, it is unnecessary to circulate the cooling medium as in the prior art. Thus, the structure of the fuel cell is simplified. Further, the conductive sandwiching portion is not built in the separator as in the case of Patent Document 1, but is simply sandwiched between the fuel cells, so that the fuel cell manufacturing process is simplified. However, the manufacturing cost can be reduced. At that time, the conductive sandwiched portion is flat, facilitating the sandwich installation between the fuel cells, and the electrical connection between the fuel cells in the sandwich installation state is easy and stable. There is also an effect that.

  In the fuel cell heat radiation utilization system of the present invention, the heat radiation from the fuel cell collected in the second heat radiation device of the fuel cell is heat-exchanged by the heat exchanger, so that the heat can be efficiently removed from the battery with a simple structure. The heat dissipation can be reused.

  In the following, when the same part as the part shown in the earlier figure of the description is shown in the subsequent figure, the same part is given the same symbol and the description of the part is omitted in the subsequent figure Sometimes.

Embodiment 1 FIG.
1 to 5 illustrate a first embodiment of the fuel cell according to the present invention. FIG. 1 is a perspective view of the first embodiment, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. 3 is a partially enlarged view of FIG. 2, FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 1, and FIG. 5 is a perspective view of the first heat pipe 4a used in the first embodiment. . 1 to 5, the fuel cell 1 includes, as main parts, a stack 2 of a plurality of fuel cells 20, a terminal electrode 31, a terminal electrode 32, and a plurality of first heats as an example of the first heat dissipation device. A pipe 4a, an electrical insulating sheet 5, and a flat plate-like second heat pipe 6 as an example of the second heat radiating device are provided. The terminal electrode 31 and the terminal electrode 32 have a terminal 311 and a terminal 321 for connecting wires, respectively.

  As shown in FIG. 2, each of the plurality of fuel cells 20 includes a solid polymer film 21, a fuel electrode 22 provided on one surface of the solid polymer film 21, and having both conductivity and air permeability, a solid polymer Provided on the other surface of the membrane 21 is an oxidizer electrode 23 having both conductivity and air permeability, and a fuel gas passage 24 for supplying gas to the fuel electrode 22 or discharging gas from the fuel electrode 22. A fuel gas separator 25 and an oxidant gas separator 27 having an oxidant gas flow path 26 are provided. In addition, on the side surface of each fuel cell 20, the side surfaces of the respective elements indicated by the reference numerals 21, 22, 23, 25, and 27 are usually exposed. However, in FIG. 1 and subsequent drawings, the drawing is simplified. Therefore, the description of each element on the side surface of the fuel cell 20 is omitted.

  As shown in FIG. 5, each of the plurality of first heat pipes 4a includes a conductive sandwiched portion 41 sandwiched between the fuel cells 20 and between adjacent fuel cells 20, in other words, a laminate. The projecting portion 42 projects outward from the two side surfaces 28, and the projecting portion 42 is substantially parallel to the projecting root portion 421 extending in the same direction as the conductive sandwiching portion 41 and the side surface 28 of the laminate 2. It is comprised from the bending part 422 extended to. The dotted line DL in FIG. 5 is the level of the side surface 28 of the stacked body 2, and thus becomes a dividing line between the conductive sandwiched portion 41 and the protruding portion 42.

  The dimension of the protruding root 421, that is, the distance between the side surface 28 and the inner surface of the bent portion 422 (the surface facing the side surface 28) is determined from the standpoint of miniaturizing the fuel cell 1 as much as possible. As long as the problem of electrical short circuit with 422 can be safely avoided, it is preferably as short as possible, for example, about 1 to 5 mm is appropriate. On the other hand, the larger the bending length BL of the bent portion 422, the better the heat dissipation performance. However, if the bent length BL is excessive, the bent length 422 contacts the protruding root portion 421 of the adjacent first heat pipe 4a and is electrically short-circuited. In order to safely avoid such a short circuit problem, there is at least about 0.3 mm, particularly at least 0, between the bent tip of the bent portion 422 and the protruding root portion 421 of the adjacent first heat pipe 4. It is preferable to create a gap of about 5 mm.

  Each first heat pipe 4a is composed of a thin conductive plate material having a thickness of about 0.1 mm. Inside the space, a working liquid such as water, ammonia, acetone or the like is sealed under vacuum. In order to return the working fluid condensed and liquefied at the curved portion 422 to the conductive sandwiching portion 41 at the high temperature end, a capillary action is generated on the inner surface of the conductive sandwiching portion 41 by a groove type or a protrusion type method. ing. The conductive sandwiching portion 41 of each first heat pipe 4a has contact resistance with the fuel gas separator 25 of the fuel cell 20 on one side and the oxidant gas separator 27 of the fuel cell 20 on the other side. In order to reduce the contact resistance between the fuel cell 20 and the fuel cell 20 on both sides, the pressure is applied between the terminal electrode 31 and the terminal electrode 32. The conductive sandwiching portion 41 includes therein a plurality of block conductors 411 that electrically bridge the opposing plate members constituting the conductive sandwiching portion 41, and the block conductor 411 includes the electrical conductors described above. In addition to the bridging action, the crushing prevention action that protects the conductive sandwiching portion 41 from being crushed even by the pressure contact force between the fuel cells 20 on both sides described above, and further, the heat radiation from the fuel battery cells 20 is conducted. It also acts to efficiently transmit within the sex pinching portion 41.

  One plane is formed on the side surface 28 of the laminate 2 by the bent portions 422 of the plurality of first heat pipes 4a, and the second heat pipe 6 is installed on the plane via the electrical insulating sheet 5. . The 2nd heat pipe 6 is flat form, and in order to prevent the electrical short by the 2nd heat pipe 6 between the bending parts 422 of the 1st heat pipe 4a, it bends via the electric insulation sheet 5. It is installed on the part 422 group.

  Next, the operation of the fuel cell 1 of Embodiment 1 will be described. In the first heat pipe 4a configured as described above, the internal working fluid is boiled and evaporated by the heat radiation from the fuel cell 20 in the conductive sandwiching portion 41 that is the high temperature end, toward the bent portion 422 that is the low temperature end. Move. Then, it is cooled at the low temperature end, returned to the liquid state, and returned to the high temperature end by capillary action, whereby the heat radiation is transmitted to the second heat pipe 6 installed outside the laminate 2, and the fuel cell is transmitted from the second heat pipe 6. 1 is dissipated to the outside.

  As a result, the heat generated from the fuel cell 20 including the solid polymer film 21, the fuel electrode 22, the oxidant electrode 23, the fuel gas separator 25, and the oxidant gas separator 27 is transferred to the first heat pipe 4a. Since it is quickly transmitted from the sex pinching portion 41 toward the projecting portion 42, particularly the bent portion 422, there is no need to provide a cooling medium flow path for circulating the cooling medium as in the prior art. By adopting the heat pipe 4a, the adhesion with the fuel cell group 20 is improved, and heat radiation can be transmitted efficiently.

Embodiment 2. FIG.
6 to 7 illustrate the second embodiment of the fuel cell of the present invention. FIG. 6 is a perspective view of the second embodiment, and FIG. 7 is the first heat used in the second embodiment. It is a perspective view of the pipe 4b. The first heat pipe 4b is different from the first heat pipe 4a used in the first embodiment in that the width of the protruding portion 42 is the width of the conductive sandwiched portion 41 (as indicated by the dotted line DL in FIG. 5). The other structure is the same except that it is slightly smaller than 1/2 of the width shown. Moreover, in the fuel cell of Embodiment 2, the first heat pipe 4b has the bent portions 422 extending in the opposite directions, in other words, the first heat pipe 4b shown in FIG. The first heat pipe 4b is installed so that the S surface and the R surface alternate in the direction from the terminal electrode 31 to the terminal electrode 32 when the one surface is the S surface and the back surface is the R surface. The left half is a bent portion 422 of the first heat pipe 4b with the S surface facing the terminal electrode 32, while the right half of FIG. 6 is the first with the R surface facing the terminal electrode 32. Flat surfaces are formed by the bent portions 422 of the heat pipe 4b, and the electrical insulating sheet 5 and the second heat pipe 6 are installed on both the flat surfaces. As a result, substantially the entire top surface of the side surface 28 of the laminate 2 can be used as the installation area of the second heat pipe 6 and the heat dissipation performance is improved.

  The first heat pipe 4b has the advantage that it is easier to manufacture industrially than the first heat pipe 4a, although the heat dissipation function is slightly reduced in that the width of the protrusion 42 is smaller than that of the first heat pipe 4a. The reason is that the first heat pipe 4a is provided with a space in which the working liquid is sealed between the thin conductive plates having a thickness of about 0.1 mm as described above, and is usually a flat plate having a thickness of about 1 mm. The casing is first manufactured, and a portion of several mm at one end thereof is bent at, for example, 90 degrees to form a bent portion 422. The length BL of the bent portion 422 (see FIG. 5) Since the size is slightly smaller than the thickness of the battery cell 20 (usually about 3 to 8 mm), it is generally not easy to bend the battery cell 20 uniformly over the entire width of the flat plate. If the width is reduced, for example, if it is 1/2, the bending work is facilitated, and the production efficiency of the first heat pipe 4b is improved.

  As an embodiment of the modification of the second embodiment, the entire S surface of the first heat pipe 4b may be directed toward the terminal electrode 32 or directed toward the terminal electrode 31. However, in those cases, the plane of the bent portion 422 is formed only in the right half or the left half as viewed in FIG.

Embodiment 3 FIG.
8 to 9 illustrate the third embodiment of the fuel cell of the present invention. FIG. 8 is a plan view of the third embodiment, and FIG. 9 is a side view of the third embodiment. . However, FIG. 8 shows a state where the electrical insulating sheet 5 and the second heat pipe 6 are removed. In the third embodiment, the first heat pipe 4c is used instead of the first heat pipe 4b used in the second embodiment. Like the first heat pipe 4b, the first heat pipe 4c has a width of the protruding portion 42 that is less than ½ of the width of the conductive sandwiching portion 41 (see FIG. 7), but the bent portion 422 thereof. This length BL has a length close to the thickness of two fuel cells 20. The first heat pipe 4c is installed in the direction from the terminal electrode 31 to the terminal electrode 32 so that the S surface and the R surface are alternated as in the case of the second embodiment. The upper side in FIG. 8 is due to the bent portion 422 of the first heat pipe 4b with the S surface facing the terminal electrode 32, while the lower surface in FIG. Flat surfaces are formed by the bent portions 422 of the first heat pipe 4b facing each other, and the electric insulating sheet 5 and the second heat pipe 6 are installed on both the flat surfaces.

  In the first heat pipe 4c, the width of the protruding portion 42 is less than ½ of the width of the conductive sandwiching portion 41, and the bent length BL of each bent portion 422 is long. The formation of the curved portion 422 is easier, which has the advantage that the production efficiency of the first heat pipe 4c is further improved.

Embodiment 4 FIG.
10 to 11 illustrate the fourth embodiment of the fuel cell of the present invention. FIG. 10 is a plan view of the fourth embodiment, and FIG. 11 is a side view of the fourth embodiment. However, FIG. 10 shows a state where the electrical insulating sheet 5 and the second heat pipe 6 are removed. In the fourth embodiment, a first heat pipe 4d is used instead of the first heat pipe 4c used in the third embodiment. Like the first heat pipe 4c, the first heat pipe 4d has a width of the projecting portion 42 that is less than ½ of the width of the conductive sandwiching portion 41, but the bent portion 422 is a fuel cell. The first heat pipe 4d has a length BL close to the thickness of 20 pieces, and the first heat pipe 4d has each bent portion 422 on both upper and lower side surfaces of the laminate 2 in FIG. Is sandwiched between the fuel cells 20 in the state described later so that the A and B surfaces are formed.

  That is, the case where the surface of the first heat pipe 4d from the terminal electrode 31 to the terminal electrode 32 is the S surface is indicated as S, and the case where the surface from the terminal electrode 31 to the terminal electrode 32 is the R surface is indicated as R. Further, when the case where the bent portion 422 is installed on the A surface side is indicated as A, and the case where the bent portion 422 is provided on the B surface side is indicated as B, the first heat pipe 4d is connected to the terminal electrode 31 from FIG. 32, from the left end of the figure, the pipe 4d is installed so that the first is in the SB state, the second is in the SA state, the third is in the RB state, and the fourth is in the RA state. Is repeated.

Embodiment 5 FIG.
FIG. 12 is a schematic perspective view of Embodiment 5 in the fuel cell heat radiation utilization system of the present invention. In FIG. 12, the fuel cell heat radiation utilization system includes a fuel cell 1 including a first heat pipe 4 and a second heat pipe 6, and a heat exchanger 7. The high temperature end 61 of the second heat pipe 6 is in thermal contact with the first heat pipe 4 via the electrical insulating sheet 5, and the low temperature end 62 is in contact with the heat exchanger 7. The heat released from the fuel cell 1 released from the first heat pipe 4 is conveyed to the heat exchanger 7 by the second heat pipe 6 and is heat-exchanged to warm water or the like here. As a result, the cooling medium circulation pump and the circulation pipe used in the prior art become unnecessary, and the heat radiation from the fuel cell 1 is efficiently sent to the heat exchanger 7 with a simple structure, and this is effectively reused. become able to.

  The present invention is not limited to the first to fifth embodiments described above, and includes various modifications in accordance with the problems of the present invention and the spirit of the solution. For example, in the first to fourth embodiments, the plane formed by the bent portion 422 is arranged in one row or two rows on a straight line in the stacking direction of the fuel cells 20, respectively. It is good also as a multi-row of 6 rows or more. Moreover, it may replace with the 1st heat pipes 4a-4d and a flat fin may be sufficient.

  The fuel cell and the fuel cell heat radiation utilization system of the present invention have a simple structure and can be made compact as compared with the prior art, and are therefore suitable for mass production and suitable for installation in a narrow space. ing.

1 is a perspective view of Embodiment 1 in a fuel cell of the present invention. Sectional drawing along the II-II line of FIG. FIG. 3 is a partially enlarged view of FIG. 2. Sectional drawing along the IV-IV line of FIG. FIG. 3 is a perspective view of a first heat pipe 4a used in the first embodiment. The perspective view of Embodiment 2 in the fuel cell of this invention. The perspective view of the 1st heat pipe 4b used in Embodiment 2. FIG. The top view of Embodiment 3 in the fuel cell of this invention (however, the state which removed the electrical insulation sheet 5 and the 2nd heat pipe 6). FIG. 9 is a side view of the third embodiment. The top view of Embodiment 4 in the fuel cell of this invention (however, the state which removed the electrical insulation sheet 5 and the 2nd heat pipe 6). FIG. 6 is a side view of a fourth embodiment. The schematic perspective view of Embodiment 5 in the fuel cell heat radiation utilization system of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell, 2 laminated body, 20 fuel battery cell, 21 solid polymer membrane,
22 fuel electrode, 23 oxidant electrode, 24 fuel gas flow path,
25 Separator for fuel gas, 26 Oxidant gas flow path, 27 Separator for oxidant gas, 28 Side surface of laminate 2, 31 terminal electrode, 32 terminal electrode,
4a-4d 1st heat pipe, 41 electroconductive clamping part, 411 block conductor,
42 Protruding part, 421 Protruding root part, 422 Bending part, 5 Electrical insulation sheet,
6 Second heat pipe, 61 High temperature end, Low temperature end 62, 7 Heat exchanger.

Claims (8)

  A stack of a plurality of fuel cells, a flat conductive sandwiched portion sandwiched between the fuel cells, and a projecting portion projecting outside from between the fuel cells and the inside of the fuel cell A fuel cell comprising a first heat radiating device for releasing the heat generated in the above to the outside.   The fuel cell includes: a solid polymer membrane; a fuel electrode disposed on one surface of the solid polymer membrane; an oxidant electrode disposed on the other surface of the solid polymer membrane; and the fuel electrode. A fuel gas conductive separator for supplying a fuel gas in contact with the oxidant gas; and an oxidant gas conductive separator for contacting the oxidant electrode and supplying an oxidant gas. The fuel cell according to claim 1.   3. The fuel cell according to claim 1, wherein the protruding portion has a flat plate shape, and an end portion of the protruding portion is bent so as to be substantially parallel to a side surface of the laminated body.   The ends of the protruding portions of the adjacent first heat radiating devices are bent in opposite directions so as not to contact each other, or protruded to the outside in different directions from between the fuel cells. 4. The fuel cell according to claim 3, wherein   5. The fuel cell according to claim 3, further comprising a second heat dissipating device on an outer surface of the bent portion of the protruding portion via an electric insulating sheet.   The fuel cell according to any one of claims 1 to 5, wherein the first heat dissipation device is a heat pipe.   The fuel cell according to claim 6, wherein the conductive sandwiching portion of the heat pipe has a block conductor that electrically bridges between opposing plate members constituting the conductive sandwiching portion.   A fuel comprising the fuel cell according to any one of claims 5 to 7, further comprising a heat exchanger for exchanging heat from the fuel cell collected in the second heat radiating device. Battery heat dissipation system.

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