Abstract:
A case configuring a fuel cell system is divided into a module section, a first fluid supply section, a second fluid supply section, and an electric section. The electric section is provided with a first intake vent for intake of an oxidant gas from outside the case into the electric section. The second fluid supply section is provided with a second intake vent for intake of the oxidant gas subjected to intake from the first intake vent, into an oxidant gas supply device. The case is internally provided with first and second internal partitions which generate a bypass path for blocking straight flow of the oxidant gas from the first intake vent to the second intake vent.

Description:
RELATED APPLICATIONS 
     This application is a 35 U.S.C. 371 national stage filing of International Application No. PCT/JP2009/063544, filed Jul. 30, 2009, which claims priority to Japanese Patent Application No. 2008-229675 filed on Sep. 8, 2008 in Japan. The contents of the aforementioned applications are hereby incorporated by reference. 
     TECHNICAL FIELD 
     The present invention relates to a fuel cell system including a fuel cell module, an oxygen-containing gas supply apparatus, a power converter, a control device, and a casing at least containing the fuel cell module, the oxygen-containing gas supply apparatus, the power converter, and the control device. 
     BACKGROUND ART 
     Typically, a solid oxide fuel cell (SOFC) employs a solid electrolyte of ion-conductive oxide such as stabilized zirconia. The solid electrolyte is interposed between an anode and a cathode to form an electrolyte electrode assembly. The electrolyte electrode assembly is interposed between separators (bipolar plates). In use, normally, predetermined numbers of the electrolyte electrode assemblies and the separators are stacked together to form a fuel cell stack. 
     As the fuel gas supplied to the fuel cell, normally, a hydrogen gas produced from hydrocarbon raw material by a reformer is used. In general, in the reformer, a reformed raw material gas is obtained from hydrocarbon raw material of a fossil fuel or the like, such as methane or LNG, and the reformed raw material gas undergoes steam reforming, partial oxidation reforming, or autothermal reforming to produce a reformed gas (fuel gas). 
     In this regard, a fuel cell system (fuel cell apparatus) having a single unit case containing a fuel cell, a reformer, a power converter for converting direct power electrical energy generated in the fuel cell according to a power supply output specification, a control device, and auxiliary devices is known. 
     In particular, in the case where a high temperature fuel cell (such as a solid oxide fuel cell or a molten carbonate fuel cell) or a medium temperature fuel cell (such as a phosphoric acid fuel cell and a hydrogen membrane fuel cell) is used, the temperature in the unit case tends to be considerably high. However, the temperature of the atmosphere around the power converter, the control device, and the auxiliary devices needs to be maintained at relatively low temperature for preventing degradation in the performance and reduction in the product life. 
     For example, in a packaged fuel cell power generator apparatus disclosed in Japanese Laid-Open Patent Publication No. 04-075263, as shown in  FIG. 20 , a package  1  is provided. The package  1  includes an upstream side package chamber  1 A and a downstream side package chamber  1 B. The upstream side package chamber  1 A has a ventilation fan  3  at an intake port for intake of the external air. The downstream side package chamber  1 B is connected to a ventilation discharge port of the upstream side package chamber  1 A through a coupling duct  1 C. 
     The upstream side package chamber  1 A contains therein a power converter unit  4  including a chopper  4 A, an inverter  4 B and a controller  4 C. The downstream side package chamber  1 B contains therein a fuel cell unit  8  including a fuel cell  5 , a reactant air blower  6 A, a combustion air blower  6 B, and a fuel reformer  7 . 
     The air at normal temperature supplied into the upstream side package chamber  1 A by the ventilation fan  3  cools the power converter unit  4  by ventilation, and then, the air is supplied to the downstream side package chamber  1 B through the coupling duct  1 C. After the air is used for cooling and ventilation of the fuel cell unit  8 , the air is discharged to the outside through an exhaust port  9 . 
     Further, in a ventilating structure of a packaged fuel cell power generator apparatus disclosed in Japanese Laid-Open Patent Publication No. 05-290868, as shown in  FIG. 21 , a package  1   a  is provided. The space in the package  1   a  is divided by a heat insulating partition  3   a  having a ventilation hole  2   a  into a high temperature device chamber  4   a  and an electrical device chamber  4   b . There is formed a ventilation port  5   a  for intake of the external air, on the outer wall of the electrical device chamber  4   b . The high temperature device chamber  4   a  contains therein a fuel cell  6   a  and a fuel cell reformer  7   a.    
     The high temperature device chamber  4   a  contains therein a reactant air blower  6   b  connected to the fuel cell  6   a , and the electrical device chamber  4   b  contains therein a fuel air blower  7   b  connected to the fuel cell reformer  7   a . The electrical device chamber  4   b  contains therein a power converter  8   a , a measurement controller  8   b , auxiliary devices  8   c , and a raw fuel tank  8   d . It is required to control the temperature of the atmosphere around these devices in the electrical device chamber  4   b.    
     In this package  1   a , in the presence of the heat insulating partition  3   a , the electrical device chamber  4   b  is not influenced by the heat from the high temperature device chamber  4   a . Further, according to the disclosure, the external air at normal temperature is sucked through the ventilation port  5   a  into the electrical device chamber  4   b  for forced ventilation in the electrical device chamber  4   b  to lower the temperature of the atmosphere around the power converter  8   a , the measurement controller  8   b , the auxiliary devices  8   c , the raw fuel tank  8   d  or the like. 
     SUMMARY OF INVENTION 
     In Japanese Laid-Open Patent Publication No. 04-075263, the fuel cell  5 , the reactant air blower  6 A, and the combustion air blower  6 B are placed in the downstream side package chamber  1 B. Therefore, in particular, in the case where a high temperature fuel cell is used, the optimum layout of the devices in the fuel cell system cannot be achieved depending on the operating temperature ranges and functions. Further, heat management and fluid management such as heat insulation and prevention of fluid diffusion or the like are not performed sufficiently. 
     Further, in Japanese Laid-Open Patent Publication No. 05-290868, the raw fuel tank  8   d  is placed in the electrical device chamber  4   b . Therefore, in particular, in the case where the high temperature fuel cell is used, the optimum layout of the devices in the fuel cell system cannot be achieved depending on the operating temperature ranges and functions. Further, the high temperature device chamber  4   a  is directly connected to the electrical device chamber  4   b , and heat management and fluid management such as heat insulation and prevention of fluid diffusion or the like are not performed sufficiently. 
     The present invention has been made to solve the problems of this type, and an object of the present invention is to provide a fuel cell system having a relatively simple structure in which the maintenance operation can be carried out easily, respective devices are arranged depending on the operating temperature ranges and the functions to minimize diffusion of heat and fluid and to prevent heat influence on the devices that should be operated at relatively low temperature as much as possible, improvement in the operating efficiency is achieved by effectively recovering heat radiated from the devices. 
     The present invention relates to a fuel cell system including a fuel cell module for generating electrical energy by electrochemical reactions of a fuel gas and an oxygen-containing gas, an oxygen-containing gas supply apparatus for supplying the oxygen-containing gas to the fuel cell module, a power converter for converting direct current electrical energy generated in the fuel cell module to electrical energy according to requirements specification, a control device for controlling the amount of electrical energy generated in the fuel cell module, and a casing containing at least the fuel cell module, the oxygen-containing gas supply apparatus, the power converter, and the control device. 
     The casing is divided into a module section where the fuel cell module is provided, a fluid supply section where the oxygen-containing gas supply apparatus is provided, and an electrical equipment section where the power converter and the control device are provided. 
     The electrical equipment section has a first air intake port for sucking the oxygen-containing gas from the outside of the casing into the electrical equipment section. The fluid supply section has a second air intake port for sucking the oxygen-containing gas sucked through the first air intake port into the oxygen-containing gas supply apparatus. The casing contains therein an inner partition that forms a detour channel for preventing the oxygen-containing gas from flowing straight from the first air intake port to the second air intake port. 
     In the present invention, the space in the casing is divided into the module section where the fuel cell module is provided, the fluid supply section where the oxygen-containing gas supply apparatus is provided, and the electrical equipment section where the power converter and the control device are provided. In the structure, the space in the casing is divided depending on the operating temperatures and functions, thereby to minimize diffusion of heat and fluid. In terms of functionality, the optimum layout is achieved advantageously. 
     Further, the fluid supply section forms part of an outer wall of the casing. Accordingly, the fluid supply section is cooled efficiently, and does not become hot easily. Likewise, the electrical equipment section forms part of the outer wall of the casing. Accordingly, the electrical equipment section is cooled efficiently, and does not become hot easily. Thus, heat influence on the devices that should be used at low temperature, such as the fluid supply section containing pumps and the electrical equipment section containing the control device is prevented as much as possible. The desired functions of devices are maintained, and the devices are operated reliably. 
     Further, the inner partition is provided in the casing in order to form the detour channel for preventing the oxygen-containing gas from flowing straight from the first air intake port to the second air intake port. In the structure, the oxygen-containing gas (cool air), which is external atmosphere that has been suctioned from the outside of the casing into the electrical equipment section through the first air intake port, can effectively recover heat radiated from devices in the electrical equipment section, such as the power generator and the control device. 
     Further, the oxygen-containing gas heated by recovering the radiated heat (heated air) is sucked from the electrical equipment section into the fluid supply section through the second air intake port. In the structure, it becomes possible to supply the heated oxygen-containing gas to the fuel cell module. Thus, the efficiency of operating the fuel cell module can be improved. 
     Further, since the detour channel is formed by the inner partition, the oxygen-containing gas channel in the casing becomes longer. Thus, natural convection is suppressed and forced convection is facilitated in the electrical equipment section and the fluid supply section (low temperature sections), and rise in the temperatures of the low temperature sections can be suppressed. 
     Further, since the external atmosphere, i.e., the air is directly supplied to the respective devices in the electrical equipment section through the first air intake port, rise in the temperatures of the devices can be suppressed effectively. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view schematically showing a fuel cell system according to a first embodiment of the present invention; 
         FIG. 2  is a plan view showing the fuel cell system; 
         FIG. 3  is a front view showing the fuel cell system; 
         FIG. 4  is a circuit diagram showing the fuel cell system; 
         FIG. 5  is a table showing a state where an inner partition is provided in a casing of the fuel cell system; 
         FIG. 6  is a perspective view schematically showing a fuel cell system according to a second embodiment of the present invention; 
         FIG. 7  is a plan view showing the fuel cell system; 
         FIG. 8  is a front view showing the fuel cell system; 
         FIG. 9  is a perspective view schematically showing a fuel cell system according to a third embodiment of the present invention; 
         FIG. 10  is a plan view showing the fuel cell system; 
         FIG. 11  is a front view showing the fuel cell system; 
         FIG. 12  is a perspective view schematically showing a fuel cell system according to a fourth embodiment of the present invention; 
         FIG. 13  is a plan view showing the fuel cell system; 
         FIG. 14  is a front view showing the fuel cell system; 
         FIG. 15  is a perspective view schematically showing a fuel cell system according to a fifth embodiment of the present invention; 
         FIG. 16  is a plan view showing the fuel cell system; 
         FIG. 17  is a front view showing the fuel cell system; 
         FIG. 18  is a perspective view schematically showing a fuel cell system according to a sixth embodiment of the present invention; 
         FIG. 19  is a front view showing the fuel cell system; 
         FIG. 20  is a perspective view schematically showing a fuel cell power generator apparatus disclosed in Japanese Laid-Open Patent Publication No. 04-075263; and 
         FIG. 21  is a view schematically showing a ventilation structure disclosed in Japanese Laid-Open Patent Publication No. 05-290868. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     As shown in  FIGS. 1 to 3 , a fuel cell system  10  according to a first embodiment of the present invention is used in various applications, including stationary and mobile applications. For example, the fuel cell system  10  is mounted on a vehicle. The fuel cell system  10  includes a fuel cell module  12  for generating electrical energy in power generation by electrochemical reactions of a fuel gas (hydrogen gas) and an oxygen-containing gas (air), a combustor  14  for raising the temperature of the fuel cell module  12 , a fuel gas supply apparatus (including a fuel gas pump)  16  for supplying the fuel gas to the fuel cell module  12 , an oxygen-containing gas supply apparatus (including an air pump)  18  for supplying an oxygen-containing gas to the fuel cell module  12 , a water supply apparatus (including a water pump)  20  for supplying water to the fuel cell module  12 , a power converter  22  for converting the direct current electrical energy generated in the fuel cell module  12  to electrical energy according to the requirements specification, and a control device  24  for controlling the amount of electrical energy generated in the fuel cell module  12 . The fuel cell module  12 , the combustor  14 , the fuel gas supply apparatus  16 , the oxygen-containing gas supply apparatus  18 , the water supply apparatus  20 , the power converter  22 , and the control device  24  are disposed in a single casing  26 . 
     As shown in  FIG. 4 , the fuel cell module  12  includes a fuel cell stack  34  formed by stacking a plurality of solid oxide fuel cells  32  in a vertical direction. The fuel cells  32  are formed by stacking electrolyte electrode assemblies and separators. Though not shown, each of the electrolyte electrode assemblies includes a cathode, an anode, and a solid electrolyte (solid oxide) interposed between the cathode and the anode. For example, the electrolyte is made of ion-conductive solid oxide such as stabilized zirconia. 
     As shown in  FIG. 3 , at an upper end of the fuel cell stack  34  in the stacking direction, a heat exchanger  36  for heating the oxygen-containing gas by heat-exchange with a consumed reactant gas discharged from the fuel cell stack  34  before the oxygen-containing gas is supplied to the fuel cell stack  34 , an evaporator  38  for evaporating water to produce a mixed fuel of a raw fuel (e.g., city gas) chiefly containing hydrocarbon and water vapor, and a reformer  40  for reforming the mixed fuel to produce a reformed gas are provided. 
     At a lower end of the fuel cell stack  34  in the stacking direction, a load applying mechanism  42  for applying a tightening load to the fuel cells  32  of the fuel cell stack  34  in the stacking direction indicated by the arrow A is provided (see  FIG. 4 ). 
     The reformer  40  is a preliminary reformer for reforming higher hydrocarbon (C 2+ ) such as ethane (C 2 H 6 ), propane (C 3 H 6 ), and butane (C 4 H 10 ) contained in the city gas, into raw fuel gas chiefly containing methane (CH 4 ), by steam reforming. The operating temperature of the reformer  40  is several hundred ° C. 
     The operating temperature of the fuel cell  32  is high, at several hundred ° C. In the electrolyte electrode assembly, methane in the fuel gas is reformed to obtain hydrogen, and the hydrogen is supplied to the anode. The fuel cell module  12  and the combustor  14  are surrounded by heat insulating material  68  (see  FIG. 3 ). 
     As shown in  FIG. 4 , the fuel gas supply apparatus  16  is connected to a raw fuel channel  56 , and a raw fuel branch channel  72  is provided at a position in the middle of the raw fuel channel  56  through a switching valve  70 . The raw fuel branch channel  72  is connected to the combustor  14 . 
     The oxygen-containing gas supply apparatus  18  is connected to the air supply pipe  52 , and the air branch channel  76  is connected to a switching valve  74  provided at a position in a middle of the air supply pipe  52 . The air branch channel  76  is connected to the combustor  14 . For example, the combustor  14  has a burner, and as described above, the raw fuel and the air are supplied to the combustor  14 . Instead of the burner, other means (e.g., electric heater) may be adopted. In this case, the raw fuel, the air, and electricity should be supplied selectively as necessary. 
     The water channel  58  is connected to the water supply apparatus  20 . The fuel gas supply apparatus  16 , the oxygen-containing gas supply apparatus  18 , and the water supply apparatus  20  are controlled by the control device  24 . A detector  78  for detecting the fuel gas is electrically connected to the control device  24 . For example, a commercial power source  80  (or other components such as a load or a secondary battery) is connected to the power converter  22 . 
     As shown in  FIGS. 1 to 3 , the casing  26  includes an outer frame  82  having a rectangular shape as a whole. In the outer frame  82 , a first vertical partition plate  84  and second vertical partition plates  86   a ,  86   b  are provided. The first vertical partition plate  84  divides the space in the casing  26  in a horizontal direction indicated by the arrow B. The second vertical partition plates  86   a ,  86   b  divide the space in the casing  26  in a horizontal direction indicated by the arrow C (in the direction intersecting with the direction indicated by the arrow B). 
     As shown in  FIGS. 1 and 2 , the module section  88  has a rectangular shape (polygonal shape) in a plan view, and includes the first vertical partition plate  84  as a first side surface and the second vertical partition plate  86   a  as a second side surface on both sides of one corner. There is provided a first fluid supply section  90   a  between the first vertical partition plate  84  and the outer frame  82 . Also, there is provided an electrical equipment section  92  between the second vertical partition plates  86   a ,  86   b  and the outer frame  82 . Thus, the first fluid supply section  90   a  and the electrical equipment section  92  partially form an outer wall of the casing  26 . Further, there is disposed a second fluid supply section  90   b  under the module section  88 , i.e., under a lateral partition plate  94 . 
     As shown in  FIGS. 1 and 3 , the fuel cell module  12  and the combustor  14  are disposed in the module section  88 . The fuel cell module  12  is provided above the combustor  14 . It should be noted that the fuel cell module  12  may be provided under the combustor  14 . The fuel cell module  12  and the combustor  14  are surrounded by heat insulating material  68 . The power converter  22  and the control device  24  are placed in the electrical equipment section  92 . The power converter  22  is provided above the control device  24 . 
     The first fluid supply section  90   a  contains therein the water supply apparatus  20 , the fuel gas supply apparatus  16 , and a detector  78 . The water supply apparatus  20  is placed at the lowermost position of the first fluid supply section  90   a , and the detector  78  is provided above the fuel gas supply apparatus  16 . The fuel gas supply apparatus  16  is held on a table  96  in the first fluid supply section  90   a . The oxygen-containing gas supply apparatus  18  is placed in the second fluid supply section  90   b.    
     As shown in  FIGS. 1 and 2 , the casing  26  has a rectangular shape in a plan view. The casing  26  is equipped with a first open/close door  102   a , a second open/close door  102   b , a third open/close door  102   c , and a fourth open/close door  102   d  on side surfaces of the casing  26 . Each of the first to fourth open/close doors  102   a  to  102   d  can be opened or closed at one end, with respect to the outer frame  82  of the casing  26  through hinges  104 . 
     The first open/close door  102   a  partially opens/closes the module section  88 , the second fluid supply section  90   b , and the electrical equipment section  92 . The second open/close door  102   b  partially opens/closes the module section  88 , the second fluid supply section  90   b , and the first fluid supply section  90   a . The third open/close door  102   c  partially opens/closes the first fluid supply section  90   a  and the electrical equipment section  92 . Further, the fourth open/close door  102   d  partially opens/closes the electrical equipment section  92 . 
     As shown in  FIGS. 1 and 3 , the casing  26  is rotatable about a vertical axis through a rotation mechanism  110 . The rotation mechanism  110  has, for example, a known structure such as a rotation table. 
     In the first embodiment, the electrical equipment section  92  has a first air intake port  112  for sucking the oxygen-containing gas from the outside of the casing  26  into the electrical equipment section  92 . Further, the second fluid supply section  90   b  has a second air intake port  114  for sucking the oxygen-containing gas sucked through the first air intake port  112 , into the oxygen-containing gas supply apparatus  18 . 
     The fourth open/close door  102   d  has the first air intake port  112  at an upper portion of the electrical equipment section  92  and on a side spaced from the power converter  22  and the control device  24 . The second air intake port  114  is positioned at a lower portion of the first vertical partition plate  84 , and the first air intake port  112  is provided above the second air intake port  114 . 
     There are provided a first inner partition  118  and a second inner partition  120  in the casing  26 . The first inner partition  118  and the second inner partition  120  form a detour channel  116  for preventing the oxygen-containing gas from flowing straight from the first air intake port  112  to the second air intake port  114 . As shown in  FIG. 2 , the first inner partition  118  is provided in the electrical equipment section  92 , in parallel with the second vertical partition plates  86   a ,  86   b . There is formed a clearance between the first inner partition  118  and the first open/close door  102   a  to form the detour channel  116 . 
     The distance L 1  between one wall surface  118   a  of the first inner partition  118  and the second vertical partition plate  86   a  as a wall surface of the module section  88  is smaller than the distance L 2  between the fourth open/close door  102   d  as a wall surface on a side opposite to the module section  88  and the other wall surface  118   b  of the first inner partition  118  (L 1 &lt;L 2 ). 
     Devices in the electrical equipment section  98 , i.e., the power converter  22  and the control device  24  are attached to the other wall surface  118   b  of the first inner partition  118 . The second inner partition  120  is provided in the first fluid supply section  90   a  in parallel with the first vertical partition plate  84 . An end of the second inner partition  120  is connected to the second vertical partition plate  86   b.    
     The distance L 1  between one wall surface  120   a  of the second inner partition  120  and the first vertical partition plate  84  as a wall surface of the module section  88  is smaller than the distance L 2  between the third open/close door  102   c  as a wall surface on a side opposite to the module section  88  and the other wall surface  120   b  of the second inner partition  120  (L 1 &lt;L 2 ). The water supply apparatus  20 , the fuel gas supply apparatus  16 , and the detector  78  are attached to the other wall surface  120   b  of the second inner partition  120 . 
     The first inner partition  118  and the second inner partition  120  are made of insulating material (material having low heat conductivity). For this heat insulating material (member), for example, rubber material such as Bakelite or nitrile butadiene rubber, resin material, fiberglass molded member or Honeycomb structure member may be used. At least in the first inner partition  118 , the ratios between the distance L 1  and the distance L 2  (L 1 :L 2 ) is determined to be within a range of 1:10 to 5:6. 
     Operation of the fuel cell system  10  will be described below. 
     As shown in  FIG. 4 , by operation of the fuel gas supply apparatus  16 , for example, a raw fuel such as the city gas (including CH 4 , C 2 H 6 , C 3 H 8 , C 4 H 10 ) is supplied to the raw fuel channel  56 . Further, by operation of the water supply apparatus  20 , water is supplied to the water channel  58 , and by operation of the oxygen-containing gas supply apparatus  18 , the oxygen-containing gas such as the air is supplied to the air supply pipe  52 . 
     As shown in  FIG. 3 , in the evaporator  38 , the raw fuel flowing through the raw fuel channel  56  is mixed with the water vapor, and a mixed fuel is obtained. The mixed fuel is supplied to the inlet of the reformer  40 . The mixed fuel undergoes steam reforming in the reformer  40 . Thus, hydrocarbon of C 2+  is removed (reformed), and a reformed gas (fuel gas) chiefly containing methane is obtained. The reformed gas flows through the outlet of the reformer  40 , and the reformed gas is supplied to the fuel cell stack  34 . Thus, the methane in the reformed gas is reformed, and the hydrogen gas is obtained. The fuel gas chiefly containing the hydrogen gas is supplied to the anodes (not shown). 
     The air supplied from the air supply pipe  52  to the heat exchanger  36  moves along the heat exchanger  36 , and is heated to a predetermined temperature by heat exchange with the exhaust gas as described later. The air heated by the heat exchanger  36  is supplied to the fuel cell stack  34 , and the air is supplied to the cathodes (not shown). 
     Thus, in each of the electrolyte electrode assemblies, by electrochemical reactions of the fuel gas and the air, power generation is performed. The hot exhaust gas (several hundred ° C.) discharged to the outer circumferential region of each of the electrolyte electrode assemblies flows through the heat exchanger  36 , and heat exchange with the air is carried out. The air is heated to a predetermined temperature, and the temperature of the exhaust gas is decreased. 
     In the first embodiment, the space in the casing  26  is divided into the module section  88  containing the fuel cell module  12 , the second fluid supply section  90   b  where the oxygen-containing gas supply apparatus  18  is provided, and the electrical equipment section  92  where the power converter  22  and the control device  24  are provided. That is, the space in the casing  26  is divided depending on the operating temperatures and the functions. In the structure, diffusion of heat and fluid is minimized. In terms of functionality, the optimum layout of the devices in the fuel cell system can be achieved. 
     Further, the second fluid supply section  90   b  is positioned under the lower surface (lateral partition plate  94 ) of the module section  88 . Since the second fluid supply section  90   b  partially forms a lower wall (outer wall) of the casing  26 , the second fluid supply section  90   b  is cooled efficiently, and does not become hot easily. 
     Further, the first fluid supply section  90   a  is provided on a first side surface (first vertical partition plate  84 ) of the module section  88 . Since the first fluid supply section  90   a  partially form the outer wall of the casing  26 , the first fluid supply section  90   a  is cooled efficiently, and does not become hot easily. 
     Likewise, the electrical equipment section  92  is provided on a second side surface (second vertical partition plates  86   a ,  86   b ) of the module section  88 . Since the electrical equipment section  92  partially forms the outer wall of the casing  26 , the electrical equipment section  92  is cooled efficiently, and does not become hot easily. 
     The temperatures of the electrical equipment section  92  containing the control device  24  and the second fluid supply section  90   b  containing the pumps need to be maintained at low temperature (around 40° C.). In the structure, functions of the devices in the electrical equipment section  92  and the second fluid supply section  90   b  are maintained suitably, and the devices are operated reliably. 
     Further, in the first embodiment, the first air intake port  112  for sucking the oxygen-containing gas (external air) from the outside of the casing  26  is provided in the electrical equipment section  92 , and the second air intake port  114  for sucking the oxygen-containing gas sucked through the first air intake port  112  into the oxygen-containing gas supply apparatus  18  is provided in the second fluid supply section  90   b . The first inner partition  118  and the second inner partition  120  are provided in the casing  26 , and the first inner partition  118  and the second inner partition  120  form the detour channel  116  in the casing  26 . The detour channel  116  prevents the oxygen-containing gas from flowing straight from the first air intake port  112  to the second air intake port  114 . 
     In the structure, the oxygen-containing gas sucked from the outside of the casing  26  to the electrical equipment section  92  through the first air intake port  112  can effectively recover heat radiated from the power converter  22  and the control device  24  in the electrical equipment section  92 . Then, after the oxygen-containing gas is heated by recovering the radiated heat, the heated oxygen-containing gas from the electrical equipment section  92  flows through the detour channel  116 , and the oxygen-containing gas is sucked through the second air intake port  114  into the second fluid supply section  90   b . Thus, by the sucking action of the oxygen-containing gas supply apparatus  18 , the heated oxygen-containing gas is supplied to the fuel cell module  12 , and improvement in the efficiency of operating the fuel cell module  12  is achieved. 
     Further, in the casing  26 , the detour channel  116  is formed by the first inner partition  118  and the second inner partition  120 . Therefore, the oxygen-containing gas channel in the casing  26  becomes longer, and as a result, natural convection is suppressed and forced convection is facilitated in the low temperature sections, i.e., the electrical equipment section  92  and the second fluid supply section  90   b . Thus, the low temperature sections effectively do not become hot excessively. 
     Further, the oxygen-containing gas (fresh air) in the outside atmosphere can be supplied directly to the power converter  22  and the control device  24  in the electrical equipment section  92  through the first air intake port  112 . Thus, rise in temperatures of the power converter  22  and the control device  24  is suppressed effectively. 
     Further, as shown in  FIG. 2 , the distance L 1  between one wall surface  118   a  of the first inner partition  118  and the second vertical partition plate  86   a  as a wall surface of the module section  88  is smaller than the distance L 2  between the other wall surface  118   b  of the first inner partition  118  and the fourth open/close door  102   d  as a wall surface on a side opposite to the module section  88  (L 1 &lt;L 2 ). 
     In the structure, the flow rate of the oxygen-containing gas flowing between the second vertical partition plate  86   a  and the first inner partition  118  is increased. Natural convection is suppressed, and forced convection is facilitated in the electrical equipment section  92 . Thus, rise in temperature of the electrical equipment section  92  (low temperature section) is suppressed effectively. 
     The oxygen-containing gas flowing between the second vertical partition plate  86   a  and the first inner partition  118  can effectively recover heat radiated from the high temperature section, i.e., the module section  88 . Thus, it becomes possible to supply the oxygen-containing gas heated to a high temperature to the fuel cell module  12 . Thus, improvement in the efficiency of operating the fuel cell module  12  is achieved. 
     Further, as shown in  FIG. 5 , preferably, the ratio between the distance L 1  and the distance L 2  (L 1 :L 2 ) is determined to be within a range of 1:10 to 5:6. If the distance L 1  is smaller than in the above range, the first inner partition  118  is positioned close to the hot second vertical partition plate  86   a . Therefore, heat conductance tends to occur, and the power converter  22  and the control device  24  attached to the first inner partition  118  may be influenced by the heat undesirably. 
     If the distance L 1  is larger than in the above range, the flow rate of the oxygen-containing gas flowing between the second vertical partition plate  86   a  and the first inner partition  118  becomes considerably small. Therefore, natural convection occurs, and the efficiency in recovering the high heat is lowered, and the power converter  22  and the control device  24  attached to the first inner partition  118  may be influenced by the heat undesirably. 
     Therefore, by determining the relationship between the distance L 1  and the distance L 2  to satisfy the above range, natural convection is suppressed, and rise in the temperature of the low temperature section is accordingly suppressed. Further, the efficiency in recovering the radiated heat by the oxygen-containing gas is improved. 
     In the first embodiment, the power converter  22  and the control device  24  are attached to the other wall surface  118   b  of the first inner partition  118 . Thus, the power converter  22  and the control device  24  are not influenced by the heat radiated from the module section  88  (high temperature section), and rise in the temperatures of the power converter  22  and the control device  24  is suppressed suitably. 
     Further, since the oxygen-containing gas (fresh air) sucked through the first air intake port  112  is directly supplied to the power converter  22  and the control device  24  in the electrical equipment section  92 , rise in the temperature in the power converter  22  and the control device  24  is suppressed further reliably. Further, the second inner partition  120  is provided in the first fluid supply section  90   a , and the same advantages as in the case of the electrical equipment section  92  are achieved. 
     Further, in the electrical equipment section  92 , the power converter  22  which radiates a large amount of heat is provided at an upper position of the casing  26 , i.e., above the control device  24 . In the structure, the control device  24  which radiates a small amount of heat is not influenced by the heat radiated from the power converter  22  having the large amount of heat radiation. Thus, rise in the temperature of the control device  24  is suppressed. 
     Further, the first air intake port  112  is provided above the second air intake port  114 . Thus, the oxygen-containing gas from the outside flows from the first air intake port  112  at the upper position through the detour channel  116 , and flows smoothly into the second air intake port  114  at the lower position. Thus, natural convection in the electrical equipment section  92  and the first fluid supply section  90   a  (low temperature sections) is suppressed, and forced convection is facilitated. Thus, rise in the temperatures in the low temperature sections is suppressed effectively. 
     Further, the first inner partition  118  is made of heat insulating material. Thus, the power converter  22  and the control device  24  attached to the other wall surface  118   b  of the first inner partition  118  are not influenced easily by the heat radiated from the module section  88 . Thus, rise in the temperatures of the power converter  22  and the control device  24  is suppressed reliably. 
     It should be noted that the first inner partition  118  may be made of heat conductive material (material having high heat conductivity) instead of heat insulating material. As the heat conductive material, for example, a zinc-coated steel plate, an aluminum plate, a copper plate may be used. Further, it is preferable to increase the contact area between the first inner partition  118  and the power converter  22  and the control device  24  or apply grease or the like to the contact area between the first inner partition  118  and the power converter  22  and the control device  24  for reducing the contact heat resistance. In this manner, heat is radiated from the power converter  22  and the control device  24  through the first inner partition  118 . Thus, rise in the temperatures of the power converter  22  and the control device  24  is suppressed advantageously. 
     Further, the fuel cell module  12  is particularly advantageous when it is a solid oxide fuel cell (SOFC) module used for a high temperature fuel cell system. However, instead of the solid oxide fuel cell module, the present invention is also suitably applicable to the other types of high temperature fuel cell modules and medium temperature fuel cell modules. For example, molten-carbonate fuel cells (MCFC), phosphoric acid fuel cells (PAFC), hydrogen membrane fuel cells (HMFC), and the like can be adopted suitably. 
       FIG. 6  is a perspective view schematically showing a fuel cell system  130  according to a second embodiment of the present invention.  FIG. 7  is a plan view showing a fuel cell system  130 .  FIG. 8  is a front view showing the fuel cell system  130 . 
     The constituent elements that are identical to those of the fuel cell system  10  according to the first embodiment are labeled with the same reference numerals, and descriptions thereof will be omitted. Further, also in third to sixth embodiments as described later, the constituent elements that are identical to those of the fuel cell system  10  according to the first embodiment are labeled with the same reference numerals, and descriptions thereof will be omitted. 
     A fluid supply section  90  is provided between a first vertical partition plate  84  and an outer frame  82  of a casing  132  of the fuel cell system  130 . The fluid supply section  90  is vertically divided into two sections, i.e., a first supply section  136  and a second supply section  138  by a lateral partition plate  134 . A fuel gas supply apparatus  16  and a detector  78  are placed in the first supply section  136 , and the detector  78  is provided above the fuel gas supply apparatus  16 . An oxygen-containing gas supply apparatus  18  and a water supply apparatus  20  are placed in the second supply section  138 , and the water supply apparatus  20  is provided at the lowermost position of the fluid supply section  90 . The oxygen-containing gas supply apparatus  18  is placed on a table  140  in the second supply section  138 . 
     A second inner partition  120  is provided in the fluid supply section  90 , and a second air intake port  114  is formed at a lower position of the second inner partition  120 . The detector  78 , the fuel gas supply apparatus  16 , the oxygen-containing gas supply apparatus  18 , and the water supply apparatus  20  are attached to the other wall surface  120   b  of the second inner partition  120 . 
     In the second embodiment, when the oxygen-containing gas supply apparatus  18  is operated, the oxygen-containing gas (external air) is sucked through the first air intake port  112  into the electrical equipment section  92 , and the oxygen-containing gas cools the interior of the electrical equipment section  92 . Further, after the oxygen-containing gas flows through the detour channel  116 , the oxygen-containing gas is sucked through the second air intake port  114  of a second external partition  122  into the fluid supply section  90 . 
     In the structure, the same advantages as in the case of the first embodiment are obtained. In particular, it is possible to prevent the oxygen-containing gas supply apparatus  18  provided in the fluid supply section  90  from being influenced by the heat radiated from the module section  88  as much as possible. 
       FIG. 9  is a perspective view schematically showing a fuel cell system  150  according to a third embodiment of the present invention.  FIG. 10  is a plan view showing the fuel cell system  150 , and  FIG. 11  is a front view showing the fuel cell system  150 . 
     The space in a casing  152  of the fuel cell system  150  is divided in a direction indicated by an arrow B by a first vertical partition plate  84  and a second vertical partition plate  86  arranged at a predetermined interval in the direction indicated by the arrow B. 
     The space in the casing  152  is divided in the direction indicated by the arrow B, into the module section  88 , the fluid supply section  90 , and the electrical equipment section  92 . The fluid supply section  90  is interposed between the module section  88  and the electrical equipment section  92 . The fluid supply section  90  has the same structure as in the case of the second embodiment, and the description thereof will be omitted. 
     An inner partition  154  having a substantially L-shape in a plan view (see  FIG. 10 ) is provided in the fluid supply section  90 . The distance L 1  between one wall surface  154   a  of the inner partition  154  and the first vertical partition plate  84  serving as a wall of the module section  88  is smaller than the distance L 2  between the other wall surface  154   b  of the inner partition  154  and the second vertical partition plate  86  (and the distance L 2  between the second vertical partition plate  86  and an outer frame  82 ) (L 1 &lt;L 2 ). 
     A first air intake port  112  is provided adjacent to an upper corner of the electrical equipment section  92 , and a second air intake port  114  is provided adjacent to a lower corner of the inner partition  154 . 
     In the third embodiment, when the oxygen-containing gas supply apparatus  18  is operated, the external air as the oxygen-containing gas is sucked through the first air intake port  112  into the electrical equipment section  92 . After the oxygen-containing gas cools the devices in the electrical equipment section  92 , the oxygen-containing gas flows through a detour channel  116  formed on the fluid supply section  90 , and the oxygen-containing gas is sucked through the second air intake port  114  into the second supply section  138 . 
     Thus, in particular, the oxygen-containing gas flows suitably and smoothly between the first vertical partition plate  84  and the inner partition  154 . Thus, it becomes possible to prevent the devices in the fluid supply section  90  from being influenced by the heat radiated from the module section  88  (high temperature section). 
     In the third embodiment, as in the cases of the first and second embodiments, open/close doors may be provided on the casing  152 . Additionally, rotation tables, traveling wheels or the like may be provided. Further, also in fourth to sixth embodiments, rotation tables, traveling vehicles or the like may be provided. 
       FIG. 12  is a perspective view schematically showing a fuel cell system  160  according to a fourth embodiment of the present invention.  FIG. 13  is a plan view showing the fuel cell system  160 , and  FIG. 14  is a front view showing the fuel cell system  160 . 
     As in the case of the third embodiment, the space in a casing  162  of the fuel cell system  160  is divided in a direction indicated by an arrow B by a first vertical partition plate  84  and a second vertical partition plate  86 . A fluid supply section  90  and an electrical equipment section  92  are provided on both sides of a module section  88  in the direction indicated by the arrow B. 
     A first inner partition  164  is provided at the electrical equipment section  92  of the casing  162 , and a second inner partition  166  is provided at the module section  88  of the casing  162 . Further, a third inner partition  168  is provided at the fluid supply section  90 . The first inner partition  164  is provided in parallel with the second vertical partition plate  86 , and spaced from the second vertical partition plate  86  by the distance L 1 . One end of the first inner partition  164  is positioned inside the outer frame  82 , and partially forms the detour channel  116 . The second inner partition  166  extends in the direction indicated by the arrow B, and the second inner partition  166  is connected to the ends of the first vertical partition plate  84  and the second vertical partition plate  86 . The third inner partition  168  is provided in parallel with the first vertical partition plate  84 , and spaced from the first vertical partition plate  84  by the distance L 1 . 
     The distance L 2  between the first inner partition  164  and the outer frame  82  in the electrical equipment section  92  is determined, and the distance L 2  between the third inner partition  168  and the outer frame  82  in the fluid supply section  90  is determined. A first air intake port  112  is formed at an upper position of the electrical equipment section  92 , and a second air intake port  114  is formed at a lower position of the third inner partition  168 . 
     In the fourth embodiment, by operation of the oxygen-containing gas supply apparatus  18 , the oxygen-containing gas is sucked through the first air intake port  112  into the electrical equipment section  92 , and the oxygen-containing gas flows through the detour channel  116  formed by the first inner partition  164 , the second inner partition  166 , and the third inner partition  168 . Then, the oxygen-containing gas is sucked through the second air intake port  114  into the second supply section  138 . Thus, in the fourth embodiment, the same advantages as in the case of the first to third embodiments are obtained. 
       FIG. 15  is a perspective view schematically showing a fuel cell system  170  according to a fifth embodiment of the present invention.  FIG. 16  is a plan view showing the fuel cell system  170 , and  FIG. 17  is a front view showing the fuel cell system  170 . 
     As in the case of the fourth embodiment, the space in a casing  172  of the fuel cell system  170  is divided in a direction indicated by an arrow B through a first vertical partition plate  84  and a second vertical partition plate  86 . The space in the casing  172  is divided into a module section  88 , and a first fluid supply section  90   a  and an electrical equipment section  92  on both sides of the module section  88  in the direction indicated by the arrow B. 
     A second fluid supply section  90   b  is provided under the module section  88 , i.e., under a lateral partition plate  94 . A first air intake port  112  is provided at an upper position of the electrical equipment section  92 , and a second air intake port  114  is provided at a lower position of the first vertical partition plate  84 . 
     A first inner partition  164 , a second inner partition  166 , and a third inner partition  168  forming a detour channel  116  are provided in the casing  172 . The detour channel  116  prevents the oxygen-containing gas from flowing straight from the first air intake port  112  into the second air intake port  114 . 
     In the fifth embodiment, the same advantages as in the case of the first to fourth embodiments are obtained. 
       FIG. 18  is a perspective view schematically showing a fuel cell system  180  according to a sixth embodiment of the present invention.  FIG. 19  is a front view showing the fuel cell system  180 . 
     A second fluid supply section  90   b  is provided in a casing  182  of the fuel cell system  180 . The second fluid supply section  90   b  has a gas discharging port  184  for discharging the oxygen-containing gas that has not been consumed in the oxygen-containing gas supply apparatus  18  (unconsumed oxygen-containing gas) to the outside of the casing  182 . A gas discharging fan  186  is attached to the external side of the casing  182 , at the gas discharging port  184 . 
     In the sixth embodiment, the unconsumed oxygen-containing gas that has been sucked through the first air intake port  112  by operation of the oxygen-containing gas supply apparatus  18 , does not stagnate in the second fluid supply section  90   b . This is because the unconsumed oxygen-containing gas in the second fluid supply section  90   b  is forcibly discharged to the outside through the gas discharging port  184  by operation of the gas discharging fan  186 . 
     Thus, the oxygen-containing gas sucked through the first air intake port  112  into the casing  182  is forcibly supplied from the second air intake port  114  to the second fluid supply section  90   b  through the detour channel  116 . Accordingly, supply of the heated oxygen-containing gas to the fuel cell module  12   a  is facilitated, and improvement in the efficiency of operating the fuel cell module  12   a  is achieved. 
     Moreover, natural convection is suppressed to a greater extent, and forced convection is facilitated in the electrical equipment section  92  and the second fluid supply section  90   b  (low temperature sections). Thus, rise in the temperatures of the low temperature sections is suppressed suitably. 
     In the sixth embodiment, in effect, the fuel cell system  10  according to the first embodiment is used. However, the present invention is not limited in this respect. The features of the sixth embodiment are also applicable to the second to fifth embodiments.