JP5111036B2 - Fuel cell stack and fuel cell - Google Patents

Description

  The present invention relates to a fuel cell stack formed by arranging a plurality of fuel cells and a fuel cell containing the fuel cell stack.

  In recent years, as a next generation energy, a fuel cell stack formed by arranging a plurality of fuel cells that can obtain electric power using fuel gas and air (oxygen-containing gas) and connecting them in series electrically. Various fuel cells stored in a storage container have been proposed.

  Hydrogen gas is used as the fuel gas used for power generation in this fuel cell, the hydrogen gas is brought into contact with the fuel-side electrode layer of the fuel cell, and the oxygen-containing gas is brought into contact with the air-side electrode layer of the fuel cell. Electric power is generated by causing an electrode reaction of

  Here, many fuel cell stacks in which a plurality of fuel cells are arranged have been proposed (see, for example, Patent Document 1).

FIG. 7 shows a schematic diagram of an example of such a fuel cell stack. FIG. 7 is a side view (a) schematically showing a conventional fuel cell stack 51 and a partially enlarged plan view (b), in which a plurality of fuel cells are arranged side by side and adjacent fuel cells are arranged. The intervals between the cells are arranged uniformly. In addition, in (b), the part corresponding to the part surrounded by the dotted line frame shown in (a) is indicated by an arrow for clarity.
JP 2003-308857 A

  Here, the fuel cells constituting the fuel cell stack generate heat with power generation. Then, the heat generated by the power generation of the fuel cell is dissipated through a gap between adjacent fuel cells.

  However, in a fuel cell stack in which a plurality (particularly a large number) of fuel cells are arranged, the fuel cells dissipate thermal energy due to Joule heat or reaction heat of the fuel cells themselves during power generation. In a plurality of fuel cells arranged in the center part in the arrangement direction, since a large number of fuel cells are arranged on both sides of the fuel cells, heat energy is not easily dissipated and tends to become high temperature.

  On the other hand, the plurality of fuel cells arranged at the end in the arrangement direction of the fuel cells has few or no fuel cells arranged adjacent to each other, and heat energy is easily dissipated. Thereby, the temperature of the fuel cells arranged on the end side in the arrangement direction of the fuel cells tends to decrease.

  For this reason, the temperature in the arrangement direction of the fuel cells is used as the fuel cell stack because the temperature in the central portion in the arrangement direction of the fuel cells is high and the temperature on the end side in the arrangement direction of the fuel cells is low. Becomes non-uniform (mountainous) and power generation efficiency may be reduced.

  Accordingly, an object of the present invention is to provide a fuel cell stack capable of making the temperature distribution in the arrangement direction of the fuel cells uniform (to make it uniform) and suppressing a decrease in power generation efficiency, and the fuel cell stack. It is to provide a fuel cell.

  The fuel cell stack of the present invention is arranged in such a manner that a plurality of fuel cells formed by sequentially laminating a fuel side electrode layer, a solid electrolyte layer and an air side electrode layer on a support substrate are connected in series. The fuel cell stack is configured such that an interval between the plurality of fuel cells arranged in the center portion in the arrangement direction of the fuel cells is arranged at an end portion in the arrangement direction of the fuel cells. It is characterized by being wider than the interval between the plurality of fuel cells.

  In such a fuel cell stack, an interval between a plurality of fuel cells arranged in a central portion (hereinafter sometimes abbreviated as a central portion) in the arrangement direction of the fuel cells is defined as the distance between the fuel cells. The temperature distribution in the arrangement direction of the fuel cell stack is made uniform because it is wider than the interval between the plurality of fuel cells arranged at the end in the arrangement direction (hereinafter sometimes abbreviated as the end). (Can be made uniform).

  That is, in a fuel cell stack in which a plurality of fuel cells are arranged, the fuel cells dissipate thermal energy due to the Joule heat or reaction heat of the fuel cells themselves during power generation, but are arranged in the center. Since a large number of fuel cells are arranged in both directions of the fuel cell, this heat energy is difficult to dissipate and becomes high temperature.

  On the other hand, the fuel cells arranged at the end in the arrangement direction of the fuel cells have few or no fuel cells arranged in one direction, and the heat energy is easily dissipated, so that the temperature is lowered. There is a tendency.

  As a result, the temperature distribution at the center of the fuel cell stack is high and the temperature at the end of the fuel cell stack is low, resulting in a non-uniform temperature distribution, which may reduce power generation efficiency.

  Therefore, in the fuel cell stack of the present invention, the interval between the plurality of fuel cells arranged in the center portion in the arrangement direction of the fuel cells is arranged at the end portion in the arrangement direction of the fuel cells. By making it wider than the interval between the plurality of fuel cells, the plurality of fuel cells arranged in the central portion can easily dissipate heat, and the temperature of the plurality of fuel cells arranged in the central portion can be reduced. Can be lowered. Further, in the plurality of fuel cells arranged at the end in the arrangement direction of the fuel cells, the interval between the fuel cells is narrower than the interval between the plurality of fuel cells arranged in the central portion. It is difficult to dissipate heat and the temperature can be suppressed from decreasing (or the temperature increases). Thereby, the temperature distribution of the fuel cell stack can be made uniform (approached uniformly), and the power generation efficiency of the fuel cell stack can be prevented from being lowered.

  In the fuel cell stack of the present invention, in the plurality of fuel cells arranged at the end, the fuel cells are adjacent to the end in the arrangement direction of the fuel cells. It is preferable that the intervals between the fuel cells be arranged so as to gradually become narrower.

  In such a fuel cell stack, in the plurality of fuel cells arranged at the end, the fuel cells are spaced from each other toward the end in the arrangement direction of the fuel cells. Since the fuel cells are arranged so as to gradually become narrower, the temperature distribution of the fuel cell stack can be made more uniform (approached uniformly), and the power generation efficiency of the fuel cell stack can be reduced. Can be suppressed.

  Further, in the plurality of fuel cells arranged at the end, the fuel cells are arranged so that the distance between the adjacent fuel cells gradually decreases toward the end in the arrangement direction of the fuel cells. Therefore, for example, an excessive stress is suppressed from being applied to a plurality of fuel cells arranged at the end portion by, for example, a gap between adjacent fuel cells rapidly widening (or narrowing). Thus, the reliability of the fuel cell stack can be improved.

  Further, in the fuel cell stack of the present invention, the thickness of the plurality of fuel cells arranged in the central portion in the arrangement direction of the fuel cells is arranged at the end in the arrangement direction of the fuel cells. It is preferable that the thickness is smaller than the thickness of the plurality of fuel cells.

  In such a fuel cell stack, when forming a fuel cell stack by arranging a plurality of fuel cells, in addition to forming the fuel cells with the same size (thickness in the arrangement direction), Different fuel cells can also be used.

  In this case, the distance between the central portions of adjacent fuel cells (for example, the distance between the fuel gas passages) is constant, and a plurality of fuel cells arranged in the central portion in the arrangement direction of the fuel cells. By making the thickness of the fuel cell smaller than the thickness of the plurality of fuel cells arranged at the end in the arrangement direction, the interval between the plurality of fuel cells arranged in the center is changed to the end. It can be made wider than the interval between the plurality of fuel cells arranged in the. Thereby, the temperature distribution in the arrangement direction of the fuel cell stack can be made uniform (approached uniformly).

  In the fuel cell stack of the present invention, the fuel cell is a hollow plate type fuel cell and is erected on a manifold for supplying fuel gas to the fuel cell. It is preferable.

  In such a fuel cell stack, the fuel cell is a hollow plate type, and the fuel cell is arranged upright on a manifold for supplying fuel gas to the fuel cell. A fuel cell stack in which fuel cells are arranged by changing the interval between adjacent fuel cells can be easily manufactured, and fuel gas can be supplied to the fuel cells.

  In addition, by making the fuel cell into a hollow flat plate type, it is possible to easily produce a fuel cell stack in which electric resistance is low, high power generation performance can be expressed, and the interval between adjacent fuel cells is different. can do.

  A fuel cell according to the present invention is a fuel obtained by storing a fuel cell stack according to any one of the above and an oxygen-containing gas supply means for supplying an oxygen-containing gas to the fuel cell in a storage container. A battery, wherein oxygen-containing gas is supplied from a side surface side of the fuel battery cell stack along the arrangement direction of the fuel battery cells, and the oxygen-containing gas flows between the fuel battery cells. To do.

  In such a fuel cell, a fuel cell stack and an oxygen-containing gas supply means for supplying an oxygen-containing gas to the fuel cell are accommodated in a storage container, and the fuel cell is arranged along the arrangement direction of the fuel cells. Since the oxygen-containing gas is supplied from the side surface side of the battery cell stack and the supplied oxygen-containing gas flows between the fuel battery cells, the temperature of the fuel battery cell is lowered by the oxygen-containing gas flowing between the fuel battery cells. be able to.

  In this case, in the fuel cell stack formed by arranging a plurality of fuel cells, since the interval between the plurality of fuel cells arranged in the center in the arrangement direction of the fuel cells is wide, This increases the flow rate of the oxygen-containing gas flowing between the plurality of fuel cells arranged in (1), thereby increasing the cooling effect of the plurality of fuel cells arranged in the center.

  On the other hand, in the plurality of fuel cells arranged at the end in the arrangement direction of the fuel cells, the interval between adjacent fuel cells is more than the interval between the plurality of fuel cells arranged in the center. Therefore, the flow rate of the oxygen-containing gas flowing between the plurality of fuel cells arranged at the end is less than the flow rate between the fuel cells arranged at the center, and is arranged at the end. The cooling effect of the plurality of fuel cells thus made is smaller than the cooling effect of the plurality of fuel cells arranged in the center.

  As a result, the temperature distribution of the fuel cell stack can be made more uniform (can be made more uniform), the power generation efficiency of the fuel cell stack can be prevented from being lowered, and a fuel cell with improved power generation efficiency can be obtained. it can.

  In the fuel cell of the present invention, the fuel cells are electrically connected in series via a current collecting member, and the current collecting member has a shape through which the oxygen-containing gas can flow. Is preferred.

  In such a fuel cell, since the fuel cells are electrically connected in series via the current collecting member, the electricity generated by the fuel cells can be collected efficiently.

  Further, since the current collecting member has a shape through which the oxygen-containing gas can flow, the oxygen-containing gas supplied from the side surface side of the fuel cell stack along the arrangement direction of the fuel cells is adjacent to the fuel cell. Since it can distribute | circulate easily between cells and the temperature distribution of a fuel cell stack can also be equalize | homogenized (approached uniformly), it can be set as the fuel cell which improved electric power generation efficiency.

  In the fuel cell of the present invention, the oxygen-containing gas supply means is arranged so that the oxygen-containing gas flows from the upper side to the lower side along the fuel cell in the oxygen-containing gas supply means. Is preferred.

  In such a fuel cell, since the oxygen-containing gas supply means is arranged so that the oxygen-containing gas flows from the upper side to the lower side along the fuel cell in the oxygen-containing gas supply means, the fuel battery cell The temperature distribution in the vertical direction can be made uniform (approximated to be uniform).

  Here, in the fuel cells constituting the fuel cell stack, the temperature tends to be higher at the upper part of the fuel cell and lower at the lower part of the fuel cell.

  Therefore, the oxygen-containing gas is warmed as the oxygen-containing gas flows from the upper side to the lower side through the fuel cell by flowing the inside of the oxygen-containing gas supply means along the fuel cell from the upper side to the lower side. .

  And the temperature of the lower part of a fuel cell can be raised because the warmed oxygen-containing gas flows toward the lower part of a fuel cell.

  Thereby, since the temperature distribution in the vertical direction of the fuel cell can be made uniform, the power generation efficiency of the fuel cell can be improved, and a fuel cell with improved power generation efficiency can be obtained.

  In the fuel cell of the present invention, it is preferable that a reformer for generating fuel gas to be supplied to the fuel cell is disposed above the fuel cell stack.

  In such a fuel cell, a reformer for generating fuel gas to be supplied to the fuel cell is arranged above the fuel cell stack. It will be warmed by.

  Here, since the fuel cell stack of the present invention can make the temperature distribution in the arrangement direction of the fuel cells uniform (close to the uniformity), the temperature of the reformer can be increased more efficiently. Thereby, the reforming reaction in the reformer can be performed efficiently. Therefore, a fuel cell with improved power generation efficiency can be obtained.

  In the fuel cell stack of the present invention, the interval between the plurality of fuel cells arranged in the center in the arrangement direction is between the plurality of fuel cells arranged at the end in the arrangement direction of the fuel cells. Since it is wider than the interval, the temperature distribution in the arrangement direction of the fuel cells of the fuel cell stack can be made uniform, and the decrease in power generation efficiency can be suppressed.

  FIG. 1 shows a fuel cell stack device 10 having a fuel cell stack 1, (a) is a side view schematically showing the fuel cell stack device 10, and (b) is a fuel cell stack of (a). FIG. 2 is a partially enlarged plan view of the device 10 and shows an excerpted portion surrounded by a dotted frame shown in FIG. In addition, in (b), the part corresponding to the part surrounded by the dotted line frame shown in (a) is indicated by an arrow for clarity. The same members are assigned the same numbers, and so on. Furthermore, the arrow shown with the dotted line in FIG. 1 has shown the flow direction of oxygen-containing gas.

  Here, the fuel cell stack apparatus 10 electrically connects a plurality of fuel cells 2, which are formed by sequentially laminating a fuel side electrode layer 5, a solid electrolyte layer 6, and an air side electrode layer 4 on a support substrate 8. A fuel cell stack 1 connected in series with each other is fixed to a manifold 12 with fuel cells 2 arranged in a line. In addition, a current collecting member 3a is interposed between adjacent fuel cells 2, and the fuel cell stack 1 is sandwiched from both sides in the arrangement direction of the fuel cells 2 via the end current collecting members 3b. In addition, a holding member 13 made of an alloy is provided which is erected and fixed to a manifold 12 for supplying fuel gas to the fuel cell 2.

  Note that one end (lower end portion) of the fuel battery cell 2 and the holding member 13 is embedded and joined to the manifold 12 by, for example, a glass sealing material (not shown) having excellent heat resistance.

  In the present embodiment, the fuel battery cell 2 has a hollow flat plate shape, and the fuel-side electrode layer 5, the solid electrolyte layer 6, and the air on one flat surface of a columnar conductive support substrate 8 having a pair of opposed flat surfaces. The side electrode layer 4 is laminated, and the interconnector 7 is provided on the other flat surface. In addition, a fuel gas passage 9 for circulating a reaction gas (fuel gas) is provided inside the conductive support substrate 8. In the present invention, such a shape is referred to as a hollow flat plate type.

  A P-type semiconductor 11 can also be provided on the outer surface (upper surface) of the interconnector 7. By connecting the current collecting member 3a to the interconnector 7 via the P-type semiconductor 11, the contact between the two becomes an ohmic contact, the potential drop can be reduced, and the deterioration of the current collecting performance can be effectively avoided. Become. In addition, each member which comprises the fuel cell 2 is explained in full detail later.

  Alternatively, the conductive support substrate 8 can also serve as the fuel-side electrode layer 5, and the fuel cell 2 can be configured by sequentially laminating the solid electrolyte layer 6 and the air-side electrode layer 4 on the surface thereof.

  Here, in the fuel cell stack 1 of the present invention, the interval between the plurality of fuel cells 2 arranged at the center in the arrangement direction of the fuel cells 2 is at the end in the arrangement direction of the fuel cells 2. It is characterized by being wider than the interval between the plurality of arranged fuel cells 2.

  In the present invention, the plurality of fuel cells 2 arranged at the center in the arrangement direction of the fuel cells 2 (hereinafter sometimes abbreviated as the center) are the plurality of fuel cells 2. It means the fuel cells arranged in the central part in the arrangement direction and in the vicinity thereof, and the number of the corresponding fuel cells is appropriately set according to the length of the fuel cells 2 in the arrangement direction, the size of the fuel cells 2, etc. can do.

  Conversely, the plurality of fuel cells 2 arranged at the end in the arrangement direction of the fuel cells 2 are appropriately determined depending on the length in the arrangement direction of the fuel cells 2, the size of the fuel cells 2, and the like. The number of corresponding fuel cells can be set.

  Therefore, specifically, the fuel cell 2 arranged in the region of about 1/3 of the length in the arrangement direction with the center in the arrangement direction of the fuel cell 2 as the center is arranged in the center. A plurality of fuel cells 2 can be formed, and the fuel cells 2 arranged in an area of about 1/3 of the length in the arrangement direction from the end in the arrangement direction to the center of the fuel cells 2 A plurality of fuel cells 2 arranged at the end can be formed. In addition, the fuel cell 2 which does not belong to both can also be arrange | positioned between the some fuel cell 2 arrange | positioned in the center part, and the some fuel cell 2 arrange | positioned at the edge part.

  By the way, the fuel cell stack formed by arranging a plurality of fuel cells generates heat as the fuel cells 2 generate power.

  Here, the fuel cell dissipates thermal energy by the Joule heat or reaction heat of the fuel cell itself during power generation, but the fuel cell 2 disposed at the center and the fuel cell 2 disposed at the end portion There is a difference in the dissipation of this thermal energy.

  That is, since a large number of fuel cells 2 are arranged on both sides of the fuel cell 2 arranged at the center, this heat energy is hardly dissipated, and the fuel cell 2 arranged at the end is unidirectional. In this case, since there are few or no adjacent fuel cells, thermal energy is likely to be dissipated.

  Therefore, in the fuel cell stack configured by arranging a plurality of fuel cells, a temperature distribution in the arrangement direction of the fuel cells is generated (the center portion is at a high temperature, and the end portion side is at a low temperature). As a result, the power generation performance of the fuel cell stack may be reduced.

  As is clear from FIG. 1, the fuel cell stack 1 of the present invention has an interval between the plurality of fuel cells 2 arranged at the center in the arrangement direction of the fuel cells 2. By making it wider than the interval between the plurality of fuel cells 2 arranged at the end in the arrangement direction, the fuel cells 2 arranged in the center portion can more easily dissipate heat energy, and the fuel cell stack The temperature of the central part of 1 can be lowered.

  On the other hand, in the plurality of fuel cells 2 arranged at the end, the interval between the adjacent fuel cells 2 is narrower than the interval between the plurality of fuel cells 2 arranged in the center. Thus, it is difficult to dissipate the heat energy than the center portion, and the temperature on the end side of the fuel cell stack 1 is suppressed from decreasing or the temperature on the end side is increased.

  Therefore, the fuel cell stack 1 of the present invention can have a gentler temperature distribution than the conventional fuel cell stack, and further, by adjusting the interval between the adjacent fuel cells 2, the fuel cell The temperature distribution of the cell stack 1 can be made close to uniform.

  Therefore, the fuel cell stack 1 of the present invention can be a fuel cell stack 1 with improved power generation performance.

  Moreover, the space | interval between the some fuel cell 2 arrange | positioned at an edge part should just be narrower than the space | interval between the some fuel cell 2 arrange | positioned at a center part, and it arrange | positions at a center part or an edge part. In the plurality of fuel cells 2 formed, the interval between the adjacent fuel cells 2 can be made constant, and in the plurality of fuel cells 2 arranged at the end, the adjacent fuel cells 2 It is good also as a structure which becomes a space | interval between gradually widening toward an edge part.

  In addition, the other member which comprises the fuel cell stack 1 of this invention is demonstrated below.

  The support substrate 8 is required to be gas permeable in order to permeate the fuel gas to the fuel side electrode layer 5, and to be conductive in order to collect current via the interconnector 7. Therefore, as the support substrate 8, it is necessary to adopt a material satisfying such a requirement as a material, and for example, conductive ceramics, cermet, or the like can be used.

  The current collecting member 3a and the end current collecting member 3b can be composed of a member made of an elastic metal or alloy, or a member obtained by adding a required surface treatment to a felt made of metal fiber or alloy fiber. Note that the current collecting member 3a in the present invention is more preferably a member made of an alloy having elasticity in order to electrically connect the fuel cells 2 having different intervals. Thereby, the fuel cell 2 can be electrically connected. Note that, for example, the current collecting member 3 a can be arranged in a different size in accordance with the interval between the fuel cells 2. The shape of the current collecting member 3a will be described later.

The air-side electrode layer 4 is not particularly limited as long as it is generally used. For example, the air-side electrode layer 4 can be formed from a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. The air-side electrode layer 4 needs to have gas permeability, and the open porosity is preferably 20% or more, particularly preferably in the range of 30 to 50%.

As the fuel-side electrode layer 5, generally known ones can be used, and porous conductive ceramics such as ZrO ₂ (referred to as stabilized zirconia) in which a rare earth element is dissolved, Ni and / or It can be formed from NiO.

The solid electrolyte layer 6 has a function as an electrolyte for bridging electrons between the electrodes, and at the same time, has to have a gas barrier property in order to prevent leakage between the fuel gas and the oxygen-containing gas. , 3 to 15 mol% of rare earth elements are formed from ZrO ₂ as a solid solution. In addition, as long as it has the said characteristic, you may form using another material etc.

The interconnector 7 can be formed from conductive ceramics, but since it is in contact with a fuel gas (hydrogen gas) and an oxygen-containing gas (such as air), it is necessary to have reduction resistance and oxidation resistance. Therefore, a lanthanum chromite-based perovskite oxide (LaCrO ₃ -based oxide) is preferably used. The interconnector 7 must be dense in order to prevent leakage of the fuel gas passing through the fuel gas passage 9 formed in the support substrate 8 and the oxygen-containing gas flowing outside the support substrate 8. In particular, it is preferable to have a relative density of 95% or more.

  The support substrate 8 can be, for example, a hollow plate type support substrate. Such a supporting substrate 8 is a plate-like piece that is elongated in the standing direction, and has both flat surfaces and both sides of a semicircular shape. A plurality (six in FIG. 1B) of fuel gas passages 9 are formed in the support substrate 8 so as to penetrate the interior in the standing direction. Each of the fuel cells 2 is joined to an upper wall (top plate) of a manifold 12 that supplies fuel gas by, for example, a glass seal material 12 having excellent heat resistance. A gas chamber (not shown) is communicated.

  Incidentally, when manufacturing the support substrate 8 by simultaneous firing with at least one of the fuel-side electrode layer 5 and the solid electrolyte layer 6, it is preferable to form the support substrate 8 from the iron group metal component and the specific rare earth oxide. . The conductive support substrate 8 preferably has an open porosity of 30% or more, particularly 35 to 50% in order to provide required gas permeability, and the conductivity is 300 S / cm or more. In particular, it is preferably 440 S / cm or more.

Furthermore, as the P-type semiconductor layer 11, a layer made of a transition metal perovskite oxide can be exemplified. Specifically, a material having higher electron conductivity than a lanthanum chromite-based perovskite oxide (LaCrO ₃ -based oxide) constituting the interconnector 7, for example, LaMnO in which Mn, Fe, Co, etc. exist in the B site. P-type semiconductor ceramics made of at least one of _three- based oxides, LaFeO ₃ -based oxides, LaCoO ₃ -based oxides and the like can be used. In general, the thickness of the P-type semiconductor layer 6 is preferably in the range of 30 to 100 μm.

  In FIG. 1, the fuel cell 2 constituting the fuel cell stack 1 is a hollow plate type fuel cell, and the fuel cell 2 having the same thickness (the same thickness in the arrangement direction) is used. An example is shown. Thereby, the fuel cell stack 1 in which the interval between the fuel cells 2 is changed can be easily manufactured by arranging the fuel cells 2 while changing the interval. For example, the thickness (thickness in the arrangement direction) can be changed when the fuel cells are arranged with a predetermined interval between the fuel cells.

  Further, in the case where the interval between adjacent fuel cells arranged in the central portion is made wider than the interval between adjacent fuel cells arranged on the end side, the interval is determined depending on the shape of the fuel cell or the fuel. It can be set appropriately depending on the number of battery cells. For example, the fuel cell spacing at the center can be 3 mm, and the fuel cell spacing at the end can be 2 mm. In addition, the space | interval of a fuel cell can be made between the surfaces of an adjacent fuel cell here.

  In FIG. 2, in the plurality of fuel cells in which the fuel cells 2 are arranged at the ends, the distance between the adjacent fuel cells 2 is gradually narrowed toward the ends in the arrangement direction of the fuel cells 2. The example of the fuel cell stack apparatus 14 arrange | positioned so that it may become is shown. (A) is a side view schematically showing the fuel cell stack device 14, (b) is a partially enlarged plan view of the fuel cell stack device 14 of (a), and is shown in (a). The part enclosed by the dotted line frame is extracted and shown. In addition, in (b), the part corresponding to the part surrounded by the dotted line frame shown in (a) is indicated by an arrow for clarity.

  In such a fuel cell stack 15, in the plurality of fuel cells 2 arranged at the end, the interval between the adjacent fuel cells 2 is directed toward the end in the arrangement direction of the fuel cells 2. The temperature distribution of the fuel cell stack 15 can be made more uniform because it is arranged so as to become gradually narrower.

  Here, in the plurality of fuel cells arranged at the end, the fuel cells are arranged so that the interval between the adjacent fuel cells 2 is gradually narrowed toward the end in the arrangement direction. Thus, for example, when the interval between the adjacent fuel cells 2 is suddenly widened (or narrowed), it is possible to suppress excessive stress from being applied to the fuel cells 2 and the current collecting member 3a. The reliability of the cell stack 14 can be improved.

  Furthermore, in a fuel cell stack in which a plurality of fuel cells 2 are arranged, the fuel cells 2 are arranged in the direction of the fuel cells 2 from the center to the end in the arrangement direction of the fuel cells 2. It can arrange | position so that a space | interval may become narrow gradually.

  FIG. 2 shows such a fuel cell stack device 14, whereby the temperature distribution of the fuel cell stack 15 can be made more uniform.

  FIG. 3 shows a fuel cell stack in which the thickness of the plurality of fuel cells 2 arranged at the center is made thinner than the thickness (thickness in the arrangement direction) of the plurality of fuel cells 2 arranged at the end. An example of the device 16 is shown. (A) is a side view schematically showing the fuel cell stack device 16, (b) is a partially enlarged plan view of the fuel cell stack device 16 of (a), and is shown in (a). The part enclosed by the dotted line frame is extracted and shown. In addition, in (b), the part corresponding to the part surrounded by the dotted line frame shown in (a) is indicated by an arrow for clarity.

  In such a fuel cell stack 17, a distance between adjacent fuel cells (for example, a distance between the central portions of the fuel cells 2 in a plan view) is set to a predetermined distance, and a plurality of fuel cells arranged in the central portion are arranged. By making the thickness of each of the fuel cells 2 thinner than the thickness of the plurality of fuel cells 2 arranged at the end, adjacent fuel cells 2 in the plurality of fuel cells arranged in the center portion The interval between them can be made wider than the interval between adjacent fuel cells 2 in the plurality of fuel cells arranged at the end.

  Specifically, for example, the distance between the adjacent fuel cells 2 (the distance between the central portion of the fuel cells 2 and the central portion of the fuel cells 2 adjacent thereto) is 5 mm, and a plurality of the fuel cells arranged in the central portion. By setting the thickness of the fuel cell 2 of 2 mm and the thickness of the plurality of fuel cells 2 arranged at the end to 3 mm, the interval between the plurality of fuel cells 2 arranged at the center is The interval between the plurality of fuel cells 2 arranged at the end can be made wider. Note that the distance between adjacent fuel cells 2 and the thickness of the fuel cells 2 can be appropriately set according to the size of the fuel cells, the size of the fuel cell stack, etc., for example, a plurality of fuel cells at the end. In the cell, the thickness of the fuel cell 2 can be appropriately changed within a range that is thinner than the thickness of the plurality of fuel cells 2 arranged in the center.

  As a result, the plurality of fuel cells 2 arranged in the center portion can more easily dissipate heat energy, and the temperature of the center portion of the fuel cell stack 17 can be lowered, and the temperature distribution of the fuel cell stack 17 can be reduced. Can be made uniform.

  Then, the fuel cell stack as described above and the oxygen-containing gas supply means for supplying the oxygen-containing gas (usually air) to the fuel cell 2 are housed in the housing container. The fuel cell can be obtained.

  FIG. 4 is an external perspective view showing an example of the fuel cell of the present invention. The fuel cell 18 is configured by housing the above-described fuel cell stack and the oxygen-containing gas supply means 20 for supplying the oxygen-containing gas to the fuel cell 2 inside a rectangular parallelepiped storage container 19. In addition, as a fuel cell stack, the example using the fuel cell stack 1 shown in FIG. 1 is shown.

  Further, in order to obtain hydrogen gas used in the fuel cell 2, a reformer 21 for reforming fuel such as natural gas or kerosene to generate hydrogen gas is disposed on the upper part of the fuel cell stack 1. is doing. In FIG. 4, the fuel cell stack device 10 is shown as a configuration including the reformer 6.

  FIG. 4 shows a state in which a part (front surface and rear surface) of the storage container 19 is removed and the fuel cell stack device 10 stored in the storage container 19 is taken out rearward. Here, in the fuel cell 18 shown in FIG. 4, the fuel cell stack device 10 can be slid and stored in the storage container 19.

  FIG. 5 is a cross-sectional view of the fuel cell 18 shown in FIG. The storage container 19 constituting the fuel cell 18 has a double structure having an inner wall 22 and an outer wall 23, and an outer frame of the storage container 19 is formed by the outer wall 23, and the fuel cell stack 1 (fuel cell) is formed by the inner wall 22. A power generation chamber 24 for accommodating the cell stack device 10) is formed. In addition, between the inner wall 22 and the outer wall 23, it is set as the flow path of the reactive gas introduce | transduced into the fuel cell 2, for example, oxygen-containing gas etc. which are introduce | transduced into the fuel cell 2 flow.

  Here, the inner wall 22 extends from the upper surface of the inner wall 22 to the side surface side of the fuel cell stack 1 and corresponds to the width of the fuel cell stack 1 in the arrangement direction, and is formed by the inner wall 22 and the outer wall 23. , An oxygen-containing gas introduction member 20 which is an oxygen-containing gas supply means for introducing the oxygen-containing gas into the fuel cell 2 is provided. A blower outlet 25 for introducing an oxygen-containing gas into the fuel cell 2 is provided at the lower end side of the oxygen-containing gas introduction member 20 (lower end side of the fuel cell 2).

  In FIG. 5, the oxygen-containing gas introduction member 20 is formed by forming an oxygen-containing gas introduction flow path by a pair of plate members arranged in parallel at a predetermined interval and joining the bottom member on the lower end side. Yes. In FIG. 5, the oxygen-containing gas introduction member 20 is disposed so as to be positioned between two fuel cell stacks 1 (fuel cell stack device 10) juxtaposed inside the storage container 19. Note that the oxygen-containing gas introduction member 20 may be disposed so as to be sandwiched from, for example, both side surfaces of the fuel cell stack 1 depending on the number of the fuel cell stacks 1 accommodated.

  Further, a temperature sensor 26 (for example, a thermocouple) having a temperature measuring unit 27 is inserted into the oxygen gas introduction member 20 from the upper surface side of the storage container 2. Thereby, the temperature of the fuel cell stack 1 (fuel cell 2) can be measured. In addition, a heat insulating material 28 is appropriately disposed in the storage container 19. A plurality of temperature sensors 26 may be disposed. In that case, it is preferable to dispose the temperature sensor 26 at the center portion and the end portion side of the fuel cell stack.

  In the fuel cell stack 1, fuel gas is supplied from the manifold 12 to the fuel cell 2, and oxygen-containing gas is supplied to the fuel cell 2, and electricity is generated using these.

  In FIG. 5, oxygen-containing gas is supplied from the side surface side of the fuel cell stack 1 along the arrangement direction of the fuel cells 2 by the oxygen-containing gas introduction member 20, and the oxygen-containing gas is interposed between the fuel cells 2. Circulate.

  That is, the oxygen-containing gas is supplied from the side of the fuel cell stack 1 and flows between the fuel cells 2, whereby heat exchange is performed between the fuel cells 2 and the oxygen-containing gas. The temperature can be lowered.

  Here, when supplying the oxygen-containing gas, it is preferable to supply the oxygen-containing gas toward the entire fuel cell stack 1 from a specific portion in the side surface direction of the fuel cell 2 (fuel cell stack 1).

  In the fuel cell stack 1 (see FIG. 4) stored in the storage container 19 shown in FIG. 5, the interval between the plurality of fuel cells 2 arranged at the center in the arrangement direction of the fuel cells 2. Since the flow rate is large, the flow rate of the oxygen-containing gas flowing between the plurality of fuel cells 2 arranged in the center increases, and the cooling effect (heat exchange) of the plurality of fuel cells 2 arranged in the center is increased. Can be increased.

  On the other hand, in the plurality of fuel cells 2 arranged at the end in the arrangement direction of the fuel cells 2, the interval between the adjacent fuel cells 2 is narrow, so that the plurality of cells arranged at the end The flow rate of the oxygen-containing gas flowing between the fuel cells 2 is smaller than the flow rate of the oxygen-containing gas flowing between the plurality of fuel cells 2 arranged in the central portion, and the fuel cell 2 in the central portion is reduced. Cooling effect is reduced.

  Therefore, the temperature of the plurality of fuel cells 2 arranged in the central portion in the arrangement direction of the fuel cells 2 is further lowered, and the temperature distribution of the fuel cell stack 1 can be made more uniform, It can suppress that the power generation efficiency of the battery cell stack 1 falls.

  Further, in the oxygen-containing gas introducing member 20 shown in FIG. 5, the oxygen-containing gas is arranged so as to flow from the upper side to the lower side along the fuel cell 2 in the oxygen-containing gas supply means 20.

  Further, in FIG. 5, a reformer 21 for supplying fuel gas (reformed gas) to the fuel cell 2 (manifold 12) is disposed above the fuel cell stack 1.

  Here, in the fuel cell having a configuration in which unreacted fuel gas is burned on the upper end side of the fuel cell 2 and the reformer 21 is heated, the fuel cell in the fuel cell 2 constituting the fuel cell stack 1 is the fuel cell. The temperature tends to be high at the top of the cell 2 and low at the bottom of the fuel cell 2.

  Therefore, the oxygen-containing gas is warmed as the oxygen-containing gas flows through the fuel cell 2 from above by flowing inside the oxygen-containing gas supply means 20 along the fuel cell 2 from above to below. It will be.

  Then, the warmed oxygen-containing gas is supplied toward the lower part of the fuel cell 20 from the air outlet 25 provided on the lower end side of the oxygen-containing gas introduction member 20. The temperature can be raised.

  Thereby, the temperature distribution in the vertical direction (standing direction) of the fuel cell 20 can be made uniform, so that the power generation efficiency of the fuel cell 20 can be improved.

  At the same time, the heat of the fuel cell stack 1 is transmitted to the reformer 21 to heat the bottom surface of the reformer 21. Thereby, the reformer 21 can advance the reforming reaction by effectively using the heat of the fuel cell stack 1.

  And since the fuel cell 18 of this invention can make the temperature distribution in the arrangement direction of the fuel cell 2 close to uniform, the temperature of the reformer 21 can also be heated more uniformly. Therefore, the reforming reaction in the reformer 21 can be performed efficiently, and the fuel cell 18 with improved power generation efficiency can be obtained.

  FIG. 6 shows an example of a current collecting member 3 a provided between adjacent fuel cells 2 in the fuel cell stack 1.

  The current collecting member 3a includes a first conductor piece 30 that contacts the flat surface of one adjacent fuel battery cell 2, and the other fuel battery cell 2 adjacent to the other fuel battery cell 2 from the end of the one adjacent fuel battery cell 2. A second conductor piece 31 extending obliquely toward the end, a third conductor piece 32 in contact with the flat surface of the other fuel cell 2, and one end from one end of the other fuel cell 2. A fourth conductor piece 33 extending obliquely toward the other end of the fuel cell 2 is provided as a basic element. The first to fourth conductive elements are connected to each other one after another in this order, and the conductor pieces are repeatedly connected in this order, so that a continuous current collecting member extending in the axial direction. 3a is formed.

  By using such a current collecting member 3a, the electricity generated by the fuel battery cell 2 can be efficiently collected and supplied from the side surface side of the fuel battery cell stack 1 along the arrangement direction of the fuel battery cells 2. The oxygen-containing gas flowing through the gap between the current collecting members 3 a can easily flow between the fuel cells 2 and can exchange heat with the fuel cells 2. The end current collecting member 3b can also have the same shape.

  Therefore, since the temperature distribution of the fuel cell stack 1 can be made closer to uniform, the power generation efficiency of the fuel cell stack 1 can be suppressed from decreasing. That is, a fuel cell with improved power generation efficiency can be obtained.

  Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention.

  For example, in the description of the fuel cell stack of the present invention, the fuel cell has been described using a hollow plate type fuel cell, but a plate type or cylindrical type fuel cell can also be used. In this case, the interval between the fuel cells can be changed by changing the sizes of the oxygen-side electrode layer, the fuel-side electrode layer, the separator, and the like constituting the fuel cell.

1 shows an example of a fuel cell stack apparatus having a fuel cell stack of the present invention, (a) is a side view schematically showing the fuel cell stack apparatus, and (b) is a fuel cell stack of (a). It is a partially expanded plan view of the apparatus. 2 shows another embodiment of a fuel cell stack device having a fuel cell stack of the present invention, (a) is a side view schematically showing the fuel cell stack device, and (b) is a diagram of (a). It is a partial enlarged plan view of a fuel cell stack device. FIG. 5 shows still another embodiment of a fuel cell stack apparatus having a fuel cell stack according to the present invention, wherein (a) is a side view schematically showing the fuel cell stack apparatus, and (b) is (a) 2 is a partially enlarged plan view of the fuel cell stack device of FIG. It is an external appearance perspective view which shows an example of the fuel cell of this invention. It is sectional drawing seen from the cut surface line XX of the fuel cell shown in FIG. It is a perspective view which shows an example of the current collection member for electrically connecting the fuel cell of this invention. 1 shows an example of a fuel cell stack device having a conventional fuel cell stack, (a) is a side view schematically showing the fuel cell stack device, and (b) is a fuel cell stack device of (a). FIG.

Explanation of symbols

1, 15, 17: Fuel cell stack 2: Fuel cell 3a: Current collecting member 3b: End current collecting member
4: Air-side electrode layer 5: Fuel-side electrode layer 6: Solid electrolyte layer 7: Interconnector 8: Support substrate 9: Fuel gas passages 10, 14, 16: Fuel cell stack device 18: Fuel cell 19: Storage container 20 : Oxygen-containing gas introduction member 21: Reformer

Claims (8)

A fuel cell stack in which a plurality of fuel cells, in which a fuel side electrode layer, a solid electrolyte layer, and an air side electrode layer are sequentially laminated, are arranged on a support substrate and electrically connected in series. The interval between the plurality of fuel cells arranged at the center in the arrangement direction of the fuel cells is the interval between the plurality of fuel cells arranged at the end in the arrangement direction of the fuel cells. A fuel cell stack characterized by being wider. In the plurality of fuel cells arranged at the end, the interval between the adjacent fuel cells gradually decreases toward the end of the fuel cells in the arrangement direction of the fuel cells. The fuel cell stack according to claim 1, wherein the fuel cell stack is disposed in a stack. The thickness of the plurality of fuel cells arranged at the center in the arrangement direction of the fuel cells is larger than the thickness of the plurality of fuel cells arranged at the end in the arrangement direction of the fuel cells. The fuel cell stack according to claim 1, wherein the fuel cell stack is thin. 2. The fuel cell according to claim 1, wherein the fuel cell is a hollow plate type fuel cell and is erected on a manifold for supplying fuel gas to the fuel cell. 4. The fuel cell stack according to any one of 3. A fuel cell comprising: a fuel cell stack according to any one of claims 1 to 4; and an oxygen-containing gas supply means for supplying an oxygen-containing gas to the fuel cell. The oxygen-containing gas is supplied from the side surface side of the fuel cell stack along the arrangement direction of the fuel cells, and the oxygen-containing gas flows between the fuel cells. Fuel cell. 6. The fuel cell is electrically connected in series via a current collecting member, and the current collecting member has a shape that allows the oxygen-containing gas to flow therethrough. Fuel cell. 6. The oxygen-containing gas supply means is arranged so that the oxygen-containing gas flows from the upper side to the lower side along the fuel cell in the oxygen-containing gas supply means. Item 7. The fuel cell according to Item 6. The reformer for producing | generating the fuel gas supplied to the said fuel battery cell is arrange | positioned above the said fuel battery cell stack, The any one of Claims 5-7 characterized by the above-mentioned. Fuel cell.

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