Fuel battery system

Abstract

To provide a fuel battery system capable of performing heating of a canister and cooling of a fuel battery stack without a need for external energy.SOLUTION: A fuel battery system 11 includes: a canister holder 13 that holds a canister 27 filled with a fuel gas; and a fuel battery stack 12. The fuel battery stack 12 includes a fuel gas supply hole 17, a fuel gas discharge hole 18, an oxygen-containing gas supply hole 19, an oxygen-containing gas discharge hole 20, a cooling fluid supply hole 21, and a cooling fluid discharge hole 22. The canister holder 13 comprises an internal channel 35 having an inflow port 29 and an outflow port 31. The canister 27 communicates with the fuel gas supply hole 17 through a first communication pipe 36. The coolant discharge hole 22 and the inflow port 29 communicate with each other through a second communication pipe 37. The outflow port 31 and the coolant supply hole 21 communicate with each other through a third communication pipe 38.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fuel cell system. [Background technology]

[0002] Generally, in a fuel cell system, when hydrogen is continuously supplied from a tank to a fuel cell, the tank cools due to an endothermic reaction that accompanies the release of hydrogen from the tank. This reduces the flow rate of hydrogen supplied from the tank to the fuel cell. On the other hand, when a fuel cell continuously generates electricity, the fuel cell generates heat. This reduces the efficiency of power generation by the fuel cell.

[0003] Thus, a conventional fuel cell system is known, for example, as disclosed in Patent Document 1. This fuel cell system includes a system housing. The system housing includes two holding shelves that divide the internal space into upper and lower sections. A fuel cell stack is disposed below the lower holding shelf. A hydrogen cylinder is disposed above the lower holding shelf. An air pump that supplies air to the fuel cell stack is disposed above the upper holding shelf.

[0004] A fuel cell guide is arranged around the fuel cell stack, surrounding it. A ventilation passage for cooling the fuel cell stack is provided inside the fuel cell guide. Openings are provided at the top and bottom of the fuel cell guide. A fan that blows air upward is arranged in the upper opening of the fuel cell guide. A vent is provided in the lower holding shelf.

[0005] When the temperature of the fuel cell stack rises due to power generation in the fuel cell stack, the fan is driven, drawing air in through an opening on the lower side of the fuel cell guide. This drawn air cools the fuel cell stack by passing through the ventilation passage. By cooling the fuel cell stack, the air that has absorbed the waste heat from the fuel cell stack is supplied by the fan to the surface of the hydrogen cylinder through the vent. This heats the hydrogen cylinder.

[0006] In this way, in the above-described fuel cell system, the fuel cell stack is air-cooled by driving the fan, and the hydrogen cylinder is heated by utilizing the exhaust heat from the fuel cell stack when air-cooling the fuel cell stack. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-181378 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the fuel cell system described above, a fan powered by external energy is essential to both heat the hydrogen cylinder and cool the fuel cell stack. Therefore, there is a demand for a fuel cell system that can both heat the hydrogen cylinder and cool the fuel cell stack without requiring external energy. [Means for solving the problem]

[0009] The means for solving the above problems and their effects will be described below. A fuel cell system that solves the above problem comprises a canister holder that holds a canister filled with fuel gas, and a fuel cell stack that generates electricity by supplying the fuel gas and oxidant gas from the canister, wherein the fuel cell stack comprises a fuel gas supply hole to which the fuel gas is supplied, a fuel gas discharge hole from which the fuel gas is discharged, an oxidant gas supply hole to which the oxidant gas is supplied, an oxidant gas discharge hole from which the oxidant gas is discharged, a coolant supply hole to which a coolant is supplied, and a coolant discharge hole from which the coolant is discharged, and the canister holder comprises an internal flow path having an inlet and an outlet, the canister and the fuel gas supply hole are connected by a first connecting pipe, the coolant discharge hole and the inlet are connected by a second connecting pipe, and the outlet and the coolant supply hole are connected by a third connecting pipe.

[0010] Normally, when fuel gas in a canister is continuously supplied to the fuel cell stack through the first connecting pipe and the fuel gas supply hole, the canister is cooled by an endothermic reaction accompanying the release of fuel gas from the canister. This reduces the flow rate of fuel gas supplied from the canister to the fuel cell stack. On the other hand, when the fuel cell stack continuously generates power, the fuel cell stack generates heat, reducing the power generation efficiency of the fuel cell stack.

[0011] In this regard, with the above configuration, the coolant supplied to the fuel cell stack from the coolant supply hole is heated within the fuel cell stack and then flows into the internal flow path via the coolant discharge hole, the second communicating pipe, and the inlet. As the coolant flows into the internal flow path, it exchanges heat with the canister via the canister holder. This heats the canister and cools the coolant. The coolant cooled in the internal flow path flows into the fuel cell stack from the coolant supply hole via the outlet and the third communicating pipe and exchanges heat with the fuel cell stack. This cools the fuel cell stack and heats the coolant. Therefore, both the canister and the fuel cell stack can be heated without requiring external energy. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram of a fuel cell system according to one embodiment. [Figure 2] FIG. 2 is a perspective view of a fuel cell stack in the fuel cell system of FIG. [Figure 3] FIG. 2 is a perspective view of a canister holder in the fuel cell system of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of a fuel cell system will now be described with reference to the drawings. <Fuel Cell System 11> As shown in FIG. 1, the fuel cell system 11 includes a fuel cell stack 12 and a canister holder 13.

[0014] <Fuel cell stack 12> As shown in FIGS. 1 and 2, the fuel cell stack 12 includes a stack 15 formed by horizontally stacking a plurality of rectangular plate-shaped unit cells 14 that generate electricity, and a pair of rectangular plate-shaped metal end plates 16 that sandwich the stack 15 from both sides in the stacking direction X of the unit cells 14.

[0015] Each unit cell 14 has a synthetic resin support frame (not shown) that supports a membrane electrode assembly (not shown) in a rectangular opening in the center, and a pair of metal separators (not shown) that sandwich the support frame supporting the membrane electrode assembly. When a fuel gas is supplied to one side (anode side) of the membrane electrode assembly in the stacking direction X and an oxidant gas is supplied to the other side (cathode side) of the membrane electrode assembly, the unit cell 14 generates electricity based on an electrochemical reaction between the fuel gas and the oxidant gas in the membrane electrode assembly. In other words, the fuel cell stack 12 generates electricity when supplied with a fuel gas and an oxidant gas. In this embodiment, the fuel gas is hydrogen and the oxidant gas is air.

[0016] The end plates 16 are made of a metal such as aluminum, and are set to be slightly larger than the unit cells 14. The pair of end plates 16 are fastened to each other at their outer edges with a plurality of bolts (not shown) and a plurality of nuts (not shown), thereby compressing the stack 15 in the stacking direction X.

[0017] One end plate 16 is formed with a fuel gas inlet 17, a fuel gas outlet 18, an oxidant gas inlet 19, an oxidant gas outlet 20, a coolant inlet 21, and a coolant outlet 22. The fuel gas inlet 17 is a hole for supplying fuel gas to the stack 15. The fuel gas outlet 18 is a hole for discharging excess fuel gas from the stack 15. The oxidant gas inlet 19 is a hole for supplying oxidant gas to the stack 15.

[0018] The oxidant gas discharge hole 20 is a hole for discharging excess oxidant gas and water produced during power generation from the stack 15. The coolant supply hole 21 is a hole for supplying a coolant W, such as cooling water, to the stack 15. The coolant discharge hole 22 is a hole for discharging the coolant W that has been heated by cooling the stack 15. The coolant supply hole 21 is located below the coolant discharge hole 22.

[0019] A pair of insulating plates 23, each having a rectangular plate shape and insulating properties, are disposed between the laminate 15 and the pair of end plates 16. The insulating plates 23 are made of, for example, synthetic resin. The size of the insulating plates 23 is set to be approximately the same as that of the end plates 16.

[0020] A pair of rectangular terminal plates 24 for collecting current are disposed between the stack 15 and the pair of insulating plates 23. The size of the terminal plates 24 is set to be approximately the same as that of the single cells 14. The terminal plates 24 have terminals 25 at their upper ends.

[0021] One insulating plate 23 and one terminal plate 24 located on the side of the end plate 16 where the holes 17 to 22 are formed have through holes (not shown) formed at positions corresponding in the stacking direction X to the holes 17 to 22. The laminate 15 has flow paths (not shown) formed at positions corresponding in the stacking direction X to the holes 17 to 22, respectively.

[0022] <Canister Holder 13> 1 and 3, the canister holder 13 is, for example, a cylindrical shape that extends vertically and has an open top and a bottom. The canister holder 13 is made of a metal such as aluminum that has a relatively high thermal conductivity. The canister holder 13 has a storage section 26 inside.

[0023] The canister holder 13 holds a metal canister 27 filled with fuel gas, with the canister 27 accommodated in the accommodation section 26 through an opening at the top end. When the canister 27 is accommodated in the accommodation section 26 of the canister holder 13, the top end of the canister 27 protrudes from the opening at the top end of the canister holder 13.

[0024] An inlet forming member 30 that forms an inlet 29 and an outlet forming member 32 that forms an outlet 31 are provided at the upper end of the peripheral wall 28 of the canister holder 13. The inlet forming member 30 and the outlet forming member 32 are arranged to face each other across the opening at the upper end of the canister holder 13.

[0025] The inlet forming member 30 and the outlet forming member 32 are connected by a pipe 34 that extends through the peripheral wall 28 and the bottom wall 33 of the canister holder 13. That is, one end of the pipe 34 is connected to the inlet forming member 30 and the other end is connected to the outlet forming member 32. The pipe 34 is made of a metal with a relatively high thermal conductivity, such as aluminum or copper.

[0026] The inlet 29 and the outlet 31 are connected by a flow path within the inlet forming member 30, a flow path within the pipe 34, and a flow path within the outlet forming member 32. The flow path from the inlet 29 to the outlet 31 forms an internal flow path 35 of the canister holder 13. Therefore, the internal flow path 35 has the inlet 29 and the outlet 31. In other words, the canister holder 13 has the internal flow path 35 having the inlet 29 and the outlet 31.

[0027] In the canister holder 13 when the canister 27 is accommodated in the accommodation portion 26, the pipe 34 forming the internal flow path 35 extends as follows: First, the pipe 34 extends spirally from the inlet-forming member 30 through the peripheral wall 28 to a position on the bottom wall 33 directly below the inlet-forming member 30 so as to surround the canister 27.

[0028] The pipe 34 then extends in a serpentine manner within the bottom wall 33 from a position directly below the inlet-forming member 30 on the bottom wall 33 to a position directly below the outlet-forming member 32. The pipe 34 then extends spirally from a position directly below the outlet-forming member 32 on the bottom wall 33 through the peripheral wall 28 to the outlet-forming member 32, surrounding the canister 27. In this manner, the pipe 34 extends from the inlet-forming member 30 to the outlet-forming member 32.

[0029] In this case, the portion of the pipe 34 that extends spirally from the inlet forming member 30 to the bottom wall 33 and the portion of the pipe 34 that extends spirally from the bottom wall 33 to the outlet forming member 32 form a double spiral structure.

[0030] <Piping configuration of fuel cell system 11> As shown in FIG. 1, the fuel cell system 11 includes a first communicating pipe , a second communicating pipe 37, and a third communicating pipe .

[0031] The first communication pipe 36 communicates the inside of the canister 27 with the fuel gas supply hole 17. Therefore, the fuel gas (hydrogen) filled inside the canister 27 is supplied from the fuel gas supply hole 17 to the fuel cell stack 12 via the first communication pipe 36. The first communication pipe 36 is formed of, for example, a flexible tube.

[0032] A supply pipe 40 extending from an oxidizing gas supply device 39 such as a pump is connected to the oxidizing gas supply hole 19. When driven, the oxidizing gas supply device 39 supplies oxidizing gas (air) from the oxidizing gas supply hole 19 to the fuel cell stack 12 via the supply pipe 40. The supply pipe 40 is formed of, for example, a flexible tube.

[0033] The second communicating pipe 37 communicates the coolant discharge hole 22 with the inlet 29. Therefore, the coolant W discharged from the coolant discharge hole 22 is supplied from the inlet 29 to the internal flow path 35 of the canister holder 13 via the second communicating pipe 37. The second communicating pipe 37 is formed of, for example, a flexible tube. A cooling pump 41 and a buffer tank 42 are provided midway along the second communicating pipe 37.

[0034] When the cooling pump 41 is driven, it causes the coolant W in the second communication pipe 37 to flow toward the inlet 29. The buffer tank 42 is disposed at a position on the second communication pipe 37 closer to the coolant discharge hole 22 than the cooling pump 41. The buffer tank 42 has a two-layer structure in which an air layer 43 where air accumulates is disposed in an upper layer and a coolant layer 44 where the coolant W accumulates is disposed in a lower layer.

[0035] The second communicating pipe 37 is cut at a certain position in the buffer tank 42, and one end of the cut portion, which is on the upstream side, is inserted into an air layer 43 inside the buffer tank 42, while the other end, which is on the downstream side, is inserted into a coolant layer 44 inside the buffer tank 42. The buffer tank 42 temporarily stores the coolant W flowing through the second communicating pipe 37, thereby removing air that has become mixed in the coolant W.

[0036] The third communication pipe 38 communicates between the outlet 31 and the coolant supply hole 21. Therefore, the coolant W flowing out from the outlet 31 is supplied to the fuel cell stack 12 from the coolant supply hole 21 via the third communication pipe 38. The third communication pipe 38 is formed of, for example, a flexible tube.

[0037] <Operation of the embodiment> 1 and 2, power generation in the fuel cell system 11 is performed as follows: Fuel gas (hydrogen) in the canister 27 is supplied to the stack 15 through the fuel gas inlet 17, and oxidant gas (air) is supplied to the stack 15 through the oxidant gas inlet 19 by driving the oxidant gas supply device 39. Furthermore, coolant W is supplied to the stack 15 through the coolant inlet 21 by driving the cooling pump 41. As a result, power generation is performed in the fuel cell stack 12 based on the electrochemical reaction of the fuel gas and oxidant gas in the membrane electrode assembly in the stack 15.

[0038] At this time, if the fuel gas (hydrogen) in the canister 27 is continuously supplied to the fuel cell stack 12, the canister 27 is cooled by an endothermic reaction accompanying the release of the fuel gas from the canister 27. This causes a problem of a decrease in the flow rate of the fuel gas supplied from the canister 27 to the fuel cell stack 12. On the other hand, if the fuel cell stack 12 is continuously generating power, the stack 15 generates heat, which causes a problem of a decrease in the power generation efficiency of the stack 15.

[0039] In this regard, in the fuel cell system 11 of this embodiment, the coolant W supplied to the fuel cell stack 12 from the coolant supply hole 21 is heated as the heat-generating stack 15 is cooled, and then discharged from the coolant discharge hole 22. The heated coolant W discharged from the coolant discharge hole 22 flows into the internal flow path 35 via the second communication pipe 37 and the inlet 29. In this case, since the coolant W discharged from the coolant discharge hole 22 contains air, the air is removed as the coolant W flows through the buffer tank 42 provided midway along the second communication pipe 37.

[0040] The coolant W, which has been heated by the laminate 15 and has had air removed in the buffer tank 42 and then flows into the internal flow path 35, exchanges heat with the canister 27 via the canister holder 13 as it flows through the internal flow path 35 from the inlet 29 to the outlet 31. In this case, the pipe 34 forming the internal flow path 35 extends spirally so as to surround the canister 27, so that heat exchange between the coolant W and the canister 27 takes place over a longer period of time.

[0041] As a result, the canister 27, which has been cooled by an endothermic reaction accompanying the release of fuel gas from the canister 27, is heated by the coolant W, and the coolant W is cooled by the cooled canister 27. The coolant W, which has been cooled by the canister 27 while flowing through the internal flow path 35, is supplied to the stack 15 from the coolant supply hole 21 via the outlet 31 and the third communicating pipe 38.

[0042] The coolant W supplied to the stack 15 from the coolant supply hole 21 exchanges heat with the stack 15. As a result, the stack 15, which has generated heat due to power generation, is cooled by the coolant W, and the coolant W is heated by the heated stack 15. After exchanging heat with the stack 15, the coolant W is discharged from the coolant discharge hole 22 to the second communicating pipe 37.

[0043] As described above, in the fuel cell system 11 of this embodiment, the circulation of the coolant W efficiently heats the canister 27 and cools the fuel cell stack 12 without requiring external energy. This ensures a sufficient flow rate of fuel gas supplied from the canister 27 to the fuel cell stack 12, and also suppresses temperature rises due to heat generation in the laminate 15 of the fuel cell stack 12. As a result, the power generation efficiency of the fuel cell system 11 is improved.

[0044] <Effects of the embodiment> According to the embodiment described above in detail, the following effects are achieved. (1) A fuel cell system 11 includes a canister holder 13 that accommodates and holds a canister 27 filled with fuel gas, and a fuel cell stack 12 that generates power by receiving fuel gas and oxidant gas from the canister 27. The fuel cell stack 12 includes a fuel gas inlet 17 through which the fuel gas is supplied, a fuel gas outlet 18 through which the fuel gas is discharged, an oxidant gas inlet 19 through which the oxidant gas is supplied, an oxidant gas outlet 20 through which the oxidant gas is discharged, a coolant inlet 21 through which the coolant W is supplied, and a coolant outlet 22 through which the coolant W is discharged. The canister holder 13 includes an internal flow path 35 having an inlet 29 and an outlet 31. The canister 27 and the fuel gas inlet 17 are connected by a first connecting pipe 36. The coolant outlet 22 and the inlet 29 are connected by a second connecting pipe 37. The outlet 31 and the coolant supply hole 21 are connected by a third connecting pipe 38.

[0045] According to the above configuration, the operation of the above embodiment makes it possible to both heat the canister 27 and cool the fuel cell stack 12 without requiring external energy.

[0046] (2) In the fuel cell system 11 , the internal flow passage 35 extends so as to surround the canister 27 . According to the above configuration, heat exchange between the coolant W flowing through the internal flow path 35 and the canister 27 can be efficiently performed.

[0047] (3) In the fuel cell system 11, the internal flow passage 35 extends in a spiral shape. According to the above configuration, heat exchange between the coolant W flowing through the internal flow path 35 and the canister 27 can be performed more efficiently.

[0048] (4) In the fuel cell system 11, a buffer tank 42 for temporarily storing the coolant W is provided midway along the second communication pipe 37. According to the above configuration, air mixed in the coolant W can be removed in the buffer tank .

[0049] <Example of change> The above embodiment can be modified as follows: Furthermore, the above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0050] The buffer tank 42 may be omitted. The internal flow path 35 does not necessarily have to extend in a spiral shape on the peripheral wall 28 of the canister holder 13. That is, the internal flow path 35 may extend in a serpentine shape on the peripheral wall 28 of the canister holder 13, for example.

[0051] The internal flow path 35 does not necessarily have to extend so as to surround the canister 27 on the peripheral wall 28 of the canister holder 13. In other words, the internal flow path 35 may extend linearly on the peripheral wall 28 of the canister holder 13, for example, along the canister 27.

[0052] The posture of the canister holder 13 and the fuel cell stack 12 in the fuel cell system 11 may be changed as needed. The arrangement of the canister holder 13 and the fuel cell stack 12 in the fuel cell system 11 may be changed as appropriate. [Explanation of symbols]

[0053] 11...Fuel cell system 12...Fuel cell stack 13...Canister holder 14...Single cell 15...Laminate 16...End plate 17...Fuel gas supply hole 18...Fuel gas exhaust hole 19...Oxidant gas supply hole 20...Oxidant gas exhaust hole 21…Cooling liquid supply hole 22…Cooling liquid discharge hole 23...Insulating plate 24...Terminal plate 25...Terminal 26...Storage section 27...Canister 28...peripheral wall 29…Inlet 30... Inlet forming member 31... Outlet 32...Outlet forming member 33...Bottom wall 34...Pipe 35...Internal flow path 36…1st communication pipe 37…Second communication pipe 38…Third communication pipe 39...Oxidant gas supply device 40…Supply pipe 41...Cooling pump 42...Buffer tank 43...Air layer 44…Cooling liquid layer W...coolant X: stacking direction

Claims

1. A fuel cell system comprising: a canister holder that holds a canister filled with fuel gas in a housed state; and a fuel cell stack that generates electricity by being supplied with the fuel gas and an oxidant gas supplied from the canister, the fuel cell stack includes a fuel gas inlet to which the fuel gas is supplied, a fuel gas outlet hole from which the fuel gas is discharged, an oxidant gas inlet to which the oxidant gas is supplied, an oxidant gas outlet hole from which the oxidant gas is discharged, a coolant inlet to which a coolant is supplied, and a coolant outlet hole from which the coolant is discharged, the canister holder includes an internal flow passage having an inlet and an outlet; the canister and the fuel gas supply hole are connected by a first communication pipe, the coolant discharge hole and the coolant inlet are communicated with each other by a second communication pipe, The fuel cell system is characterized in that the outlet and the coolant supply hole are connected to each other by a third connecting pipe.

2. 2. The fuel cell system according to claim 1, wherein the internal flow passage extends so as to surround the canister.

3. 3. The fuel cell system according to claim 2, wherein the internal flow passage extends in a spiral shape.

4. 4. The fuel cell system according to claim 1, wherein a buffer tank for temporarily storing the cooling liquid is provided in the second communication pipe.

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