JP4971545B2 - Humidification system for fuel cell - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell humidification system including a humidifier having a water-permeable hollow fiber membrane. More specifically, the humidification is such that a low-humidity gas can suitably recover moisture from a high-humidity gas. The present invention relates to a humidifying system for a fuel cell equipped with a vessel.
[0002]
[Prior art]
As a conventional humidifier using a water-permeable hollow fiber membrane, for example, there is one disclosed in JP-A-7-71795. As shown in FIG. 13, the humidifier 100 has a cylindrical housing 101. A first inflow port 102 and a first outflow port 103 for dry air are formed in the housing 101. A plurality of hollow fiber membrane bundles 104, for example, 5000 hollow fiber membranes are formed inside the housing 101. Is stored.
Further, at both ends of the housing 101, fixing portions 105 and 105 ′ for fixing the both ends of the hollow fiber membrane bundle 104 in an open state are provided. The fixing portions 105 and 105 ′ are covered with a first head cover 108 and a second head cover 109, respectively. The first head cover 108 is provided with a second inlet 106 for introducing wet air, and the second head cover 109 discharges wet air from which moisture has been separated and removed by the hollow fiber membrane bundle 104. A second outlet 107 is formed.
[0003]
In the humidifier 100 using the water-permeable hollow fiber membrane configured as described above, wet air is supplied from the first inflow port 106 to pass through each hollow fiber membrane constituting the hollow fiber membrane bundle 104. At this time, moisture in the humid air is separated by the capillary condensation action of the hollow fiber membrane, passes through the capillary of the hollow fiber membrane, and moves to the outside of the hollow fiber membrane. The moist air from which moisture has been separated is discharged from the second outlet 107.
On the other hand, dry air (low wet gas) is supplied from the first inlet 102. The dry air supplied from the first inlet 102 passes outside the hollow fiber membranes constituting the hollow fiber membrane bundle 104. The water separated from the wet air has moved to the outside of the hollow fiber membrane, and the dry air is humidified by this water. Then, the humidified dry air is discharged from the first outlet 103.
[0004]
[Problems to be solved by the invention]
However, in order to supply the humidified gas sufficiently humidified to the fuel cell stack using the humidifier having such a configuration and action, the module has a large number of hollow fiber membranes (for example, 40,000). It is necessary to increase the diameter of the hollow fiber membrane module (housing diameter) used in the humidifier or increase the number of hollow fiber membrane modules used.
However, when the diameter of the hollow fiber membrane module is increased or the number of hollow fiber membrane modules used is increased, there are the following problems.
(1) The cross-sectional area of the gas passage flowing in the hollow fiber membrane module is increased, the flow velocity is decreased, and a sufficient humidification amount cannot be secured for increasing the number of hollow fiber membranes. As a result, the power generation performance of the fuel cell stack is reduced.
(2) Further, in order to secure a predetermined humidification amount, a membrane area is further required, so that the hollow fiber membrane needs to be enlarged.
On the other hand, there is a close relationship between the cross-sectional area of the gas passage in the hollow fiber membrane module and the flow velocity and pressure loss. In order to increase the flow velocity, the cross-sectional area of the gas passage must be reduced, When the cross-sectional area of the passage is reduced to increase the gas flow rate, there are the following problems.
(3) Since the flow rate of gas increases, the amount of humidification in the gas supplied to the fuel cell increases and the power generation output of the fuel cell stack improves, but the piping pressure loss increases and the power consumption of the turbocharger increases. The ratio of the actual output that can be actually supplied to the load (for example, a traveling motor of an automobile) decreases. In the worst case, when the pressure loss increases, the temperature of the supercharger rises and breaks.
[0005]
The present invention has been made to solve the above-described problems, and can make the flow rate of the low wet gas faster than the flow rate of the high wet gas, and make the pressure loss on the low wet gas side appropriate pressure loss. An object of the present invention is to provide a fuel cell humidification system including a humidifier that can secure a sufficient humidification amount of gas supplied to the fuel cell.
[0006]
[Means for Solving the Problems]
A humidifying system for a fuel cell according to claim 1 of the present invention, which has been made to solve the above problems, includes a water-permeable hollow fiber membrane inside, and is discharged from the fuel cell by the water-permeable hollow fiber membrane. Heading to the fuel cell from highly humid gas , Higher pressure than the highly humid gas In a fuel cell humidification system comprising a humidifier that moves moisture to a gas in a low wet state, when the humidifier is obtained in a cross-section in the thickness direction of the hollow fiber membrane, the low wet state in the humidifier The total cross-sectional area of the gas passage is set to be less than the total cross-sectional area of the high-humidity state gas passage in the humidifier.
[0007]
In the fuel cell humidification system according to the first aspect of the invention, the total cross-sectional area of the low-humidity state gas passage in the humidifier is set to be less than the total cross-sectional area of the high-humidity state gas passage. The flow rate on the low wet gas side can be made faster than the flow rate on the high wet gas side. As a result, the amount of water recovered from the high wet gas side to the low wet gas side can be improved, and the efficiency of the fuel cell can also be improved.
[0008]
The invention of the humidifying system for a fuel cell according to claim 2 In the fuel cell humidification system, The total cross-sectional area of the low-humidity gas passage in the humidifier is 1500 mm. ² Over 5600mm ² It is characterized by being set to be less than.
[0009]
In the fuel cell humidification system according to the second aspect of the present invention, the total cross-sectional area of the low-humidity state gas passage in the humidifier is 1500 mm. ² Over 5600mm ² By setting it to be less than the value, the pressure loss on the low wet gas side can be set to an appropriate pressure loss, and the humidification amount of the gas supplied to the fuel cell can be set to a sufficiently satisfactory value. As a result, it is possible to operate with the most efficient performance of the actual output of the fuel cell system.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
First, an embodiment of a hollow fiber membrane module used in a humidifier of a fuel cell humidification system of the present invention will be described with reference to the drawings.
As shown to (a) of FIG. 1, the hollow fiber membrane module 1 is comprised including the housing 1a and the hollow fiber membrane bundle 1b accommodated in this housing 1a. The housing 1a has a hollow cylindrical shape with both ends open. The housing 1a is provided with a plurality of openings (around eight in the circumferential direction) in the vicinity of both ends thereof. Here, reference numeral 1w _in The opening indicated by is a high-humidity gas inlet and is denoted by 1w _out The opening indicated by is a high-humidity gas outlet. Also, reference numeral 1d _in One end of the housing 1a indicated by is a low-humidity gas inlet, _out The other end of the housing 1a indicated by is a low-humidity gas outlet.
On the other hand, the hollow fiber membrane bundle 1b accommodated in the housing 1a is obtained by bundling thousands of hollow fiber membranes HF having the hollow passage shown in FIG. 1 (b), and both end surfaces (circumferential direction) of the housing 1a. The hollow fiber membrane HF is secured with an adhesive so that the hollow passages of the hollow fiber membrane HF are not scattered.
Portions where the hollow fiber membrane bundle 1b is bonded to the housing 1a are referred to as potting portions 1g and 1h, but the gas in a low wet state flows through the hollow passage inside the hollow fiber membrane HF by the potting portions 1g and 1h. And a highly humid gas flowing outside the hollow fiber membrane HF are not mixed.
Incidentally, in such a hollow fiber membrane module 1, a bundle of a predetermined number of hollow fiber membranes HF, HF,.. Is inserted into the housing 1a, and both sides are sufficiently adhered and fixed with an adhesive, and then along the both ends of the housing 1a. Then, the bundle of hollow fiber membranes HF, HF,.
[0011]
Next, features of the hollow fiber membrane module 1 of the humidifier constituting the fuel cell humidification system will be described with reference to the drawings. In addition, as the hollow fiber membrane module 1, what filled 20-50% of hollow fiber membranes HF with an internal diameter of 0.3-0.5 mm and an external shape of 0.5-0.7 mm in the housing 1a was used.
Further, the definition of terms used as the cross-sectional area of the gas passages used thereafter will be described here with reference to FIG.
(1) The total cross-sectional area S1 in the hollow fiber membrane is a value obtained by calculating the cross-sectional area on the basis of the inner diameter of one hollow fiber membrane HF in the housing 1a and multiplying that value by the total number of hollow fiber membranes HF filled. It is.
(2) The total outside cross-sectional area S2 of the hollow fiber membrane is the total of the hollow fiber membranes HF filled with the cross-sectional area value obtained on the basis of the outer shape of one hollow fiber membrane HF from the value of the cross-sectional area based on the inner diameter of the housing 1a. The value multiplied by the number is taken as the value.
[0012]
As one embodiment using the hollow fiber membrane module 1, the relationship between the output of the fuel cell and the dew point of the low wet gas supplied to the fuel cell when moisture is exchanged between the low wet gas and the high wet gas Is shown in FIG. At this time, the flow rates per unit time of both gases introduced into the hollow fiber membrane module 1 are the same.
As can be seen from this figure, as the output of the fuel cell increases, the dew point increases and the amount of humidification improves. However, when compared with the total cross-sectional area of the gas passage, as shown by the symbol A in FIG. 2, the total cross-sectional area of the gas passage of the low wet gas is set to be less than the total cross-sectional area of the gas passage of the high wet gas. It can be seen that the dew point of the low-humidity gas becomes higher as compared with that indicated by the symbol B, which is the opposite condition. That is, it can be seen that it is preferable to improve the humidification amount so that the flow rate of the low wet gas exceeds the flow rate of the high wet gas.
On the other hand, when the total cross-sectional area of the high-humidity gas gas passage is set to be less than the total cross-sectional area of the low-humidity gas gas passage, as shown by symbol B in FIG. Since it is less than the gas flow velocity, the amount of humidification cannot be improved as indicated by the symbol A in FIG.
Accordingly, if the total cross-sectional area S1 in the hollow fiber membrane and the total cross-sectional area S2 outside the hollow fiber membrane in FIG. It can be seen that a high gas can be supplied to the fuel cell.
[0013]
Next, FIG. 3 shows the relationship between the flow rate of the low wet gas in the hollow fiber membrane module 1 and the water recovery amount. As can be seen from this figure, the amount of water recovered from the high wet gas increases as the flow rate of the low wet gas increases. However, it does not exceed the maximum value determined from the relationship between the flow rate of the low wet gas and the amount of recovered water.
[0014]
FIG. 4 shows the relationship between the total cross-sectional area of the gas passage of the low wet gas and the flow velocity. As can be seen from this figure, when the gas flow rate is constant, there is a point that the flow rate of the low wet gas decreases rapidly when the total cross-sectional area of the gas passage of the low wet gas is increased.
On the other hand, FIG. 5 shows the relationship between the total cross-sectional area of the low-humidity gas passage and the pressure loss. As can be seen from this figure, when the total cross-sectional area of the low-humidity gas passage is reduced by the method of reducing the number of hollow fiber membranes HF, the point that the pressure loss suddenly increases appears. The total cross-sectional area of the gas passage at that time is approximately 1500 mm. ² To 2000mm ² It is a point. From the results of FIGS. 4 and 5, 1500 mm, which is the total cross-sectional area of the gas passage of the low-humidity gas when the pressure loss is 20 kPa, which is the point where the gas flow velocity does not decrease rapidly and the pressure loss does not increase rapidly. ² Was the lower limit of the total cross-sectional area of the gas passage of the low wet gas.
[0015]
Next, FIG. 6 shows the relationship between the total cross-sectional area of the low-humidity gas passage and the water recovery amount. As can be seen from FIG. 6, when the total cross-sectional area of the low-humidity gas gas passage is increased, the water recovery amount also increases. However, the water recovery amount is the difference between the total cross-sectional area of the low-humidity gas gas passage and the water recovery amount. Saturation or down occurs for the following reasons with the saturation value of the water recovery amount obtained from the relationship.
That is, as shown in FIG. 4, when the total cross-sectional area of the low-humidity gas passage is increased, the flow rate of the low-humidity gas decreases. As shown in FIG. Decrease. On the other hand, as shown in FIG. 6, when the total cross-sectional area of the gas passage of the low wet gas is increased, the water recovery amount increases to a certain value. In this embodiment, the total cross-sectional area of the gas passage suitable for the low-humidity gas is approximately 5500 mm at which the water recovery amount is maximum ² From 5600mm ² It is a point.
Eventually, the optimum total cross-sectional area of the gas passage of the low-humidity gas is determined by these trade-offs. In the present embodiment, the upper limit value of the total cross-sectional area of the gas passage of the low wet gas is 5600 mm. ² Set to.
[0016]
Next, in this way 1500mm ² <Total cross-sectional area of low-humidity gas passage <5600mm ² A fuel cell humidification system using the hollow fiber membrane module 1 set to 1 will be described with reference to the drawings.
First, the fuel cell humidification system of the first embodiment will be described with reference to FIGS.
As shown in FIG. 7, the fuel cell humidification system of the first embodiment reacts hydrogen in the fuel gas supplied to the anode electrode with oxygen in the air that is an oxidant gas supplied to the cathode electrode. The fuel cell 10 that generates electric power and the two humidifiers that humidify the gas supplied to the anode and cathode of the fuel cell 10 by exchanging moisture with the gas discharged from each electrode of the fuel cell, respectively. 11 and 12, an ejector 13 that supplies fuel gas to the anode electrode while circulating the fuel gas, and an S / C (supercharger) 14 that supplies air as an oxidant gas to the cathode electrode (fuel) The battery 10 is included in the configuration of the humidification system).
[0017]
The fuel cell 10 is a solid polymer fuel cell, and generates electricity by reacting hydrogen in fuel gas with oxygen in air. The reaction formula is as follows. Formula (1) represents the reaction at the anode electrode, Formula (2) represents the reaction at the cathode electrode, and the reaction shown in Formula (3) proceeds as the entire battery. Thus, in the fuel cell 10, generated water is generated at the cathode electrode as the cell reaction proceeds. Usually, the produced water is vaporized in the air supplied to the cathode electrode and discharged from the fuel cell 10 together with the unreacted air.
H ₂ → 2H ⁺ + 2e ^- ------------------ (1)
2H ⁺ + (1/2) O ₂ + 2e ^- → H ₂ O ------- (2)
H ₂ + (1/2) O ₂ → H ₂ O ---------------- (3)
The solid polymer type fuel cell 10 uses a solid polymer membrane as an electrolyte layer, a pair of gas diffusion electrodes that sandwich the solid polymer membrane, and a gas diffusion electrode that is further sandwiched from the outside. And a structure in which a plurality of single cells having separators for separating air are stacked.
[0018]
Humidifiers 11 and 12 are humidifiers in which a module is formed using the above-described water-permeable hollow fiber membrane HF. ² <Total cross-sectional area of low-humidity gas passage <5600mm ² It is a humidifier set to.
[0019]
The ejector 13 is a kind of vacuum pump for circulating the fuel gas supplied to the anode electrode, and the main part is composed of a nozzle, a diffuser, a suction chamber and the like. It has a simple structure, is easy to operate and maintain, and has high durability because it has no moving parts such as rotation and sliding. In addition, there is an advantage that a corrosion-resistant material can be freely selected depending on the nature of the suction gas.
[0020]
The S / C (supercharger) 14 is a mechanical supercharger that sucks and pressurizes atmospheric air and supplies it to the cathode electrode of the fuel cell 10.
Instead of the S / C (supercharger) 14, a Rishorum type positive displacement compressor may be used.
[0021]
The operation of the fuel cell humidification system of the first embodiment configured as described above will be described.
The fuel gas that is a low wet gas supplied to the ejector 13 is sucked and pressurized by the ejector 13 and supplied to the humidifier 11.
The fuel gas (low-humidity gas) supplied to the humidifier 11 has a large gas passage cross-sectional area while passing through a passage having a smaller total cross-sectional area of gas passages in the hollow fiber membrane module 1 in the humidifier 11. After being humidified by exhaust gas (highly humid gas) discharged from the anode electrode of the fuel cell 10 that passes through the other passage, the fuel cell 10 is supplied to the anode electrode.
Hydrogen in the fuel gas sent to the anode electrode of the fuel cell 10 reacts with oxygen in the air supplied from the S / C (supercharger) 14 to the cathode electrode of the fuel cell 10 to generate electricity. The fuel gas that has not been used for the reaction in the fuel cell 10 becomes an exhaust gas (off gas) that is a highly humid gas, and is supplied to the humidifier 11 again.
The exhaust gas supplied to the humidifier 11 gives moisture to the fuel gas supplied from the ejector 13 to the humidifier 11 while passing through the passage having the larger total cross-sectional area of the gas passages in the hollow fiber membrane module 1. After that, it is supplied to a subsequent process (for example, a catalytic combustor). A part of the exhaust gas exiting the humidifier 11 is sucked into the ejector 13 and is circulated again as fuel gas to the anode electrode.
On the other hand, air as a low wet gas in the atmosphere is sucked and pressurized by the S / C (supercharger) 14 and supplied to the humidifier 12.
While the air (low-humidity gas) supplied to the humidifier 12 passes through the passage having the smaller total cross-sectional area of the gas passage in the hollow fiber membrane module 1 in the humidifier 12, the total cross-sectional area of the gas passage. After being humidified by exhaust gas (highly humid gas) discharged from the cathode electrode of the fuel cell 10 that passes through the larger passage, the fuel cell 10 is supplied to the cathode electrode.
The air that has not been used for the reaction with hydrogen in the fuel gas in the fuel cell 10 becomes exhaust gas, which is a highly humid gas, and is supplied to the humidifier 12 again. The exhaust gas, which is a highly humid gas supplied to the humidifier 12, passes from the S / C (supercharger) 14 to the humidifier while passing through the passage having the larger total cross-sectional area of the gas passage in the hollow fiber membrane module 1. The air supplied to 12 is moistened with moisture and supplied to a subsequent process (for example, a catalytic combustor).
[0022]
The operation results of the fuel cell humidification system of the first embodiment having the configuration and operation described above will be described with reference to FIGS. 8 to 11.
First, the relationship between the humidification amount and the stack output is shown in FIG. As can be seen from FIG. 8, when the humidification amount (moisture recovery amount) in the low-humidity gas is increased, the output of the stack increases accordingly. However, if the humidification amount increases too much, the fuel increases due to the increase of moisture. The membrane resistance of the proton conductive membrane of the battery 10 increased and the stack output did not increase.
[0023]
FIG. 9 shows the relationship between the stack pressure and the stack output. As can be seen from FIG. 9, as the stack pressure is increased, the water vapor partial pressure in the stack increases accordingly, and the stack output increases. However, if the stack pressure becomes too high, condensed water is generated in the stack. It was generated and the discharge of water worsened, and the stack output did not increase further.
[0024]
FIG. 10 shows the relationship between the discharge pressure of the S / C (supercharger) 14 and the power consumption. As can be seen from FIG. 10, in the case of a supercharger such as S / C (supercharger) 14, the current consumption increased when the discharge pressure was increased (pressure loss increased).
[0025]
Finally, FIG. 11 shows the relationship between the low wet gas pressure loss of the hollow fiber membrane module 1 and the actual output of the fuel cell. As can be seen from FIG. 11, when the pressure loss of the low wet gas in the hollow fiber membrane module 1 exceeds 20 kPa due to the balance with FIGS. 8 to 10, the pressure loss increases and the power consumption of the S / C (supercharger) 14 Since the ratio of the actual output of the fuel cell 10 that can be actually used decreases, the pressure loss is preferably 20 kPa or less.
[0026]
In the fuel cell humidification system including the fuel cell 10 and the humidifiers 11 and 12 as described above, when the humidifiers 11 and 12 obtain a cross section in the thickness direction of the hollow fiber membrane, the humidifiers 11 and 12 are obtained. The total cross-sectional area of the low-humidity gas passage is 1500mm ² Over 5600mm ² By setting the pressure to be less than the value, the pressure loss on the low-humidity gas side can be set to an appropriate pressure loss, and the humidification amount of the gas supplied to the fuel cell 10 can be set to a sufficiently satisfactory value. As a result, it has become possible to operate with the most efficient performance of the actual output of the fuel cell system.
[0027]
Next, a fuel cell humidification system according to a second embodiment will be described with reference to FIG.
The difference in configuration between the fuel cell humidification system of the second embodiment and the fuel cell humidification system of the first embodiment is to perform water exchange between the fuel gas supplied to the anode electrode and the exhaust gas discharged from the cathode electrode. A humidifier 11 ′ is provided, and a humidifier 12 ′ for humidifying the exhaust gas discharged from the humidifier 11 ′ and the air supplied to the cathode electrode of the fuel cell 10 by the S / C (supercharger) 14. It is different in that it is supplied to.
In the fuel cell humidification system of the first embodiment, the hollow fiber membranes used in the two humidifiers 11 and 12 are both porous membranes, but for the fuel cell of the second embodiment. The hollow fiber membrane used in the humidification system is a non-porous membrane that can move only the moisture in the gas in contact with the humidifier 11 'using ionic hydration, and the humidifier 12' has a capillary condensation action. The porous membrane which can permeate | transmit the water | moisture content in the gas to be used is used.
By using a non-porous membrane in a humidifier 11 'that humidifies and supplies fuel gas supplied to the anode electrode of the fuel cell 10, fuel gas (hydrogen-containing gas) and exhaust gas (oxygen gas) discharged from the cathode electrode When the moisture exchange with the contained gas) is performed, only the moisture can be passed from the cathode side to the anode side without passing the gas, so that the hydrogen gas and the oxygen gas pass through the membrane in the humidifier. There is no mixing.
[0028]
The operation of the fuel cell humidification system of the second embodiment configured as described above will be described below. In addition, the same code | symbol is attached | subjected and demonstrated about the same member as the fuel cell humidification system of 1st Embodiment.
The fuel gas, which is a low wet gas supplied to the ejector 13, is sucked and pressurized by the ejector 13 and supplied to the humidifier 11 ′.
The fuel gas (low wet gas) supplied to the humidifier 11 ′ passes through the gas passage in the hollow fiber membrane module in the humidifier 11 ′ while passing through the smaller cross-sectional area of the gas passage. After being humidified by exhaust gas (highly humid gas) discharged from the cathode electrode of the fuel cell 10 passing through the passage having the larger area, the fuel cell 10 is supplied to the anode electrode. Hydrogen in the fuel gas sent to the anode electrode of the fuel cell 10 reacts with oxygen in the air supplied from the S / C (supercharger) 14 to the fuel cell 10 to generate electricity. The fuel gas that has not been used for the reaction in the fuel cell 10 becomes exhaust gas, and is supplied to a subsequent process (for example, a catalytic combustor). A part of the exhaust gas is sucked into the ejector 13 and circulated again as fuel gas.
On the other hand, air, which is a low wet gas in the atmosphere, is sucked and pressurized by the S / C (supercharger) 14 and supplied to the humidifier 12 '.
The air (low wet gas) supplied to the humidifier 12 ′ passes through the passage having the larger total cross-sectional area of the gas passage while passing through the passage having the smaller total cross-sectional area of the gas passage of the hollow fiber membrane module. After being humidified by the exhaust gas (highly humid gas) discharged from the humidifier 11 ', it is supplied to the cathode electrode. Air that has not been used for the reaction with hydrogen in the fuel gas in the fuel cell 10 becomes exhaust gas, which is a highly humid gas, and is supplied to the humidifier 11 ′. The exhaust gas supplied to the humidifier 11 ′ gives moisture to the fuel gas supplied from the ejector 13 to the humidifier 11 ′ while passing through the passage having the larger total cross-sectional area of the gas passage of the hollow fiber membrane module. Humidified and discharged from the humidifier 11 '. The exhaust gas discharged from the humidifier 11 ′ is further supplied to the humidifier 12 ′. While passing through the passage having the larger total cross-sectional area of the gas passage of the hollow fiber membrane module, the S / C (super The air supplied from the charger 14 to the humidifier 12 'is given moisture and humidified. The exhaust gas discharged from the humidifier 12 'is supplied to a subsequent process (for example, a catalytic combustor).
[0029]
As described above, regarding the total cross-sectional area of each gas passage of the low wet gas and the high wet gas supplied to the hollow fiber membrane module, the total cross-sectional area of the low wet gas passage and the total cross-sectional area of the high wet gas passage Is set so that the total cross-sectional area of the low-humidity gas passage is less than the total cross-sectional area of the high-humidity gas passage, so that the flow rate of the low-humidity gas can be higher than the flow rate of the high-humidity gas. A sufficient amount of humidification of the gas supplied to 10 can be secured.
Further, since the amount of water recovered from the high wet gas is improved by increasing the flow rate of the low wet gas, the number of hollow fiber membranes can be reduced, and as a result, the module can be downsized.
The total cross-sectional area of the low-humidity gas passage is 1500mm. ² <Total cross-sectional area of low-humidity gas passage <5600mm ² As a result, it is possible to secure both an appropriate pressure loss and a sufficient amount of humidification, and the most efficient performance of the actual output of the fuel cell system can be found.
[0030]
【Effect of the invention】
According to the present invention having the above configuration and operation, the following effects can be obtained.
(1) According to the invention of claim 1, in the humidifying system for a fuel cell provided with the humidifier, when the humidifier is obtained in a cross section in the thickness direction of the hollow fiber membrane, the low wet gas in the humidifier By setting the total cross-sectional area of the passage to be less than the total cross-sectional area of the high-humidity gas passage in the humidifier, the flow rate on the low-humidity gas side can be made faster than the flow rate on the high-humidity gas side. As a result, the amount of water recovered from the high wet gas side to the low wet gas side can be improved, and the efficiency of the fuel cell can also be improved.
(2) According to the invention of claim 2, in the humidification system for a fuel cell provided with the humidifier, when the humidifier is obtained in a cross section in the thickness direction of the hollow fiber membrane, the low wet gas in the humidifier The total cross-sectional area of the passage is 1500mm ² Over 5600mm ² By setting it to be less than the value, the pressure loss on the low wet gas side can be set to an appropriate pressure loss, and the humidification amount of the gas supplied to the fuel cell can be set to a sufficiently satisfactory value. As a result, it is possible to operate with the most efficient performance of the actual output of the fuel cell system.
[Brief description of the drawings]
FIG. 1A is a configuration diagram showing a hollow fiber membrane module used in a humidifier of a fuel cell humidification system of the present invention.
(B) It is a figure which shows the flow of the gas in each hollow fiber membrane of the said hollow fiber membrane module.
(C) AA 'sectional view of FIG. 1 (a); It is a diagram for explaining the definition of the terms used to express the total sectional area of the gas passage.
FIG. 2 shows a fuel cell humidification system according to the present invention; an output of a fuel cell and a fuel cell when moisture is exchanged between dry air as a low-humidity gas and off-gas of the fuel cell as a high-humidity gas. It is a figure which shows the relationship with the dew point of the dry air supplied.
3 is a graph showing the relationship between the flow rate of low wet gas in the hollow fiber membrane module shown in FIG. 1 and the amount of water recovered.
FIG. 4 is a diagram showing the relationship between the total cross-sectional area of the gas passage of low wet gas and the flow velocity.
FIG. 5 is a diagram showing a relationship between a total cross-sectional area of a gas passage of low wet gas and pressure loss.
FIG. 6 is a graph showing the relationship between the total cross-sectional area of the gas passage of low wet gas and the amount of recovered water.
FIG. 7 is a diagram illustrating an overall configuration of a fuel cell humidification system according to a first embodiment.
FIG. 8 is a diagram showing a relationship between a humidification amount and a stack output of the fuel cell humidification system according to the first embodiment.
FIG. 9 is a diagram showing the relationship between the stack pressure and the stack output of the fuel cell humidification system of the first embodiment.
FIG. 10 is a diagram showing the relationship between the S / C (supercharger) discharge pressure and the power consumption of the fuel cell humidification system of the first embodiment.
FIG. 11 is a diagram showing the relationship between the low wet gas pressure loss of the hollow fiber membrane module of the fuel cell humidification system of the first embodiment and the actual output of the fuel cell.
FIG. 12 is a diagram showing an overall configuration of a fuel cell humidification system according to a second embodiment.
FIG. 13 is a longitudinal sectional view of a humidifier using a conventional water-permeable hollow fiber membrane.
[Explanation of symbols]
10 Fuel cell
11,12 Humidifier
13 Ejector
14 S / C (Supercharger)
S ₁ Total cross-sectional area in hollow fiber membrane
S ₂ Hollow fiber membrane outer cross-sectional area
HF hollow fiber membrane

Claims (2)

A water-permeable hollow fiber membrane is provided in the interior, and the water-permeable hollow fiber membrane allows high-pressure, low-humidity from the high-humidity gas discharged from the fuel cell to the fuel cell. In a fuel cell humidification system equipped with a humidifier that moves moisture to a gas in a state,
When obtaining a cross section of the humidifier in the thickness direction of the hollow fiber membrane,
A humidifying system for a fuel cell, characterized in that a total cross-sectional area of the low-humidity state gas passage in the humidifier is set to be less than a total cross-sectional area of the high-humidity state gas passage in the humidifier. . The humidification system for a fuel cell according to claim 1, the total cross-sectional area of the passage of the low wet gas is characterized in that set to be 5600mm less than ² exceed 1500 mm ² in the previous SL humidifier.

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