KR20220108569A - Fuel cell membrane humidifier and fuel cell system comprising it - Google Patents

Abstract

The present invention relates to a fuel cell membrane humidifier and fuel cell system comprising the same, capable of improving humidification efficiency by introducing exhaust gas discharged from a fuel cell stack into a fuel cell membrane humidifier in both directions. The fuel cell system according to one embodiment of the present invention comprises: a blower supplying dry gas; a fuel cell stack; and a fuel cell membrane humidifier. The fuel cell membrane humidifier comprises: a mid-case; a first inclined exhaust gas inlet into which exhaust gas discharged from the fuel cell stack is introduced and which is formed in a direction inclined at a predetermined angle on one side of one surface of the mid-case and a second inclined exhaust gas outlet which is formed in a direction inclined at a predetermined angle on the other side of the one surface of the mid-case; and an exhaust gas discharge hole which is formed on the other surface of the mid-case.

Description

Fuel cell membrane humidifier and fuel cell system comprising it

The present invention relates to a fuel cell membrane humidifier capable of improving humidification efficiency by introducing exhaust gas discharged from a fuel cell stack into the fuel cell membrane humidifier in both directions, and a fuel cell system including the same.

A fuel cell is a power generation type cell that produces electricity by combining hydrogen and oxygen. Unlike general chemical cells such as dry cells and storage batteries, fuel cells can continuously produce electricity as long as hydrogen and oxygen are supplied, and there is no heat loss, so the efficiency is about twice that of an internal combustion engine.

In addition, since chemical energy generated by the combination of hydrogen and oxygen is directly converted into electrical energy, the emission of pollutants is small. Accordingly, the fuel cell has the advantage of being environmentally friendly and reducing concerns about resource depletion due to increased energy consumption.

These fuel cells are largely dependent on the type of electrolyte used: Polymer Electrolyte Membrane Fuel Cell (PEMFC), Phosphoric Acid Fuel Cell (PAFC), Molten Carbonate Fuel Cell (Molten Carbonate Fuel Cell) : MCFC), Solid Oxide Fuel Cell (SOFC), and Alkaline Fuel Cell (AFC).

Each of these fuel cells operates on the same principle, but the type of fuel used, operating temperature, catalyst, electrolyte, etc. are different from each other. Among them, the polymer electrolyte fuel cell (PEMFC) is known to be the most promising not only in small-scale stationary power generation equipment but also in transportation systems because it operates at a low temperature compared to other fuel cells and can be miniaturized due to its high output density.

One of the most important factors in improving the performance of a polymer electrolyte fuel cell (PEMFC) is a certain amount or more of a polymer electrolyte membrane (Polymer Electrolyte Membrane or Proton Exchange Membrane: PEM) of a membrane-electrode assembly (MEA). It is to maintain moisture content by supplying moisture. This is because when the polymer electrolyte membrane is dried, the power generation efficiency is rapidly reduced.

As a method of humidifying the polymer electrolyte membrane, 1) a bubbler humidification method in which water is supplied by passing a target gas through a diffuser after filling a pressure-resistant container with water, 2) the amount of supplied water required for fuel cell reaction There are a direct injection method in which moisture is calculated and directly supplying moisture to a gas flow pipe through a solenoid valve, and 3) a humidification membrane method in which moisture is supplied to a fluidized bed of gas using a polymer membrane.

Among them, the membrane humidification method of humidifying the polymer electrolyte membrane by providing water vapor to the gas supplied to the polymer electrolyte membrane using a membrane that selectively transmits only water vapor contained in the exhaust gas is advantageous in that the humidifier can be reduced in weight and size.

The selective permeable membrane used in the membrane humidification method is preferably a hollow fiber membrane having a large permeation area per unit volume when forming a module. That is, when a humidifier is manufactured using a hollow fiber membrane, the high integration of the hollow fiber membrane with a large contact surface area is possible, so that the fuel cell can be sufficiently humidified even with a small capacity, low-cost materials can be used, and the fuel cell discharges at high temperature. It has the advantage that it can be reused through a humidifier by recovering moisture and heat contained in the off-gas.

1 is a view showing a fuel cell membrane humidifier according to the prior art and a fuel cell system including the same.

1, the fuel cell system of the prior art includes a blower (B), a membrane humidifier (10), a fuel cell stack (S), and flow paths (P1, P2, P3, P4). P1 is a dry gas supply passage for supplying the dry gas collected by the blower (B) to the membrane humidifier 10, and P2 is a humidifying gas supply for supplying the gas humidified by the membrane humidifier 10 to the fuel cell stack (S). it is euro P3 is an exhaust gas supply passage for supplying the exhaust gas discharged from the fuel cell stack S to the membrane humidifier 10, and P4 is an exhaust gas discharge passage for discharging the exhaust gas after water exchange to the outside.

The membrane humidifier 10 is a humidification module 11 and both ends of the humidification module 11 in which moisture exchange occurs between the dry gas supplied from the blower (B) and the exhaust gas (wet gas) discharged from the fuel cell stack (S). It includes caps (12, 13) coupled to.

A drying gas inlet 12a is formed in the cap 12 on the blower (B) side to supply the drying gas supplied from the blower (B) to the humidification module 11, and the cap 13 on the stack (S) side has a The dry gas outlet 13a is formed to supply the gas humidified by the humidification module 11 to the fuel cell stack S.

The humidification module 11 is a mid-case having an off-gas inlet 11aa and an off-gas outlet 11ab and a mid-case 11a and a mid-case 11a). It includes a plurality of hollow fiber membranes (11b) in the. Both ends of the bundle of hollow fiber membranes 11b are fixed to the potting part 11c. The potting part 11c is generally formed by curing a liquid polymer such as a liquid polyurethane resin through a casting method.

Dry gas supplied from the blower (B) flows along the hollow of the hollow fiber membranes (11b). The exhaust gas introduced into the mid-case 11a through the exhaust gas inlet 11aa comes into contact with the outer surface of the hollow fiber membranes 11b and then is discharged from the mid-case 11a through the exhaust gas outlet 11ab. When the exhaust gas comes into contact with the outer surface of the hollow fiber membranes 11b, moisture contained in the exhaust gas penetrates the hollow fiber membranes 11b, thereby humidifying the dry gas flowing along the hollow of the hollow fiber membranes 11b.

However, in general, it takes a considerable amount of time to be introduced through the flue gas inlet 11aa and discharged through the flue gas outlet 11ab. Although the concentration of the substance is relatively high, the concentration of the substance to be permeated gradually decreases over time. That is, as the exhaust gas flows from the exhaust gas inlet (11aa) side to the exhaust gas outlet (11ab) side, the concentration of the material to be transmitted through the hollow fiber membrane is gradually reduced, so that it is transmitted through the hollow fiber membrane placed on the side of the exhaust gas outlet (11ab). The amount of the material is also gradually reduced, so there is a problem in that the overall efficiency of the fuel cell is lowered.

Republic of Korea Patent Publication No. 10-2014-0076385

An object of the present invention is to provide a fuel cell membrane humidifier capable of improving humidification efficiency by introducing exhaust gas discharged from a fuel cell stack into the fuel cell membrane humidifier in both directions, and a fuel cell system including the same.

A fuel cell membrane humidifier according to an embodiment of the present invention,

mid-case; The exhaust gas discharged from the fuel cell stack is introduced, and a first inclined exhaust gas inlet formed in a direction inclined at a predetermined angle to one side of one side of the mid-case, and one surface of the mid-case inclined at a predetermined angle to the other side of the mid-case a second inclined type exhaust gas inlet formed in the direction; It includes; one exhaust gas outlet formed on the other surface of the mid-case.

In the fuel cell membrane humidifier according to the embodiment of the present invention, a partition wall dividing the inner space of the mid-case into a first space and a second space is included, wherein the first exhaust gas inlet is formed in the first space, , the second exhaust gas inlet may be formed in the second space.

In the fuel cell membrane humidifier according to the embodiment of the present invention, the exhaust gas outlet may be formed between the first space and the second space.

In the fuel cell membrane humidifier according to the embodiment of the present invention, the exhaust gas outlet may be formed between a partition wall dividing the first space and the second space.

A fuel cell system according to an embodiment of the present invention,

Blower for supplying dry gas; fuel cell stack; The mid-case, the exhaust gas discharged from the fuel cell stack is introduced, and a first inclined exhaust gas inlet formed in a direction inclined at a predetermined angle on one side of one side of the mid-case; and a fuel cell membrane humidifier including a second inclined exhaust gas inlet formed in an angled direction and one exhaust gas outlet formed on the other surface of the mid-case.

In the fuel cell system according to an embodiment of the present invention, a partition wall dividing the inner space of the mid-case into a first space and a second space is included, wherein the first exhaust gas inlet is formed in the first space, The second exhaust gas inlet may be formed in the second space.

In the fuel cell system according to the embodiment of the present invention, the exhaust gas outlet may be formed between the first space and the second space.

In the fuel cell system according to an embodiment of the present invention, the exhaust gas outlet may be formed between a partition wall dividing the first space and the second space.

In a fuel cell system according to an embodiment of the present invention, there is provided a fuel cell system comprising: a humidification gas supply passage for supplying the gas humidified in the fuel cell membrane humidifier to the fuel cell stack; an exhaust gas supply passage for supplying the exhaust gas discharged from the fuel cell stack to the fuel cell membrane humidifier; It may include; branching from the exhaust gas supply passage, a first exhaust gas branch passage connected to the first exhaust gas inlet and a second exhaust gas branch passage connected to the second exhaust gas inlet.

In the fuel cell system according to an embodiment of the present invention, it is formed between the first exhaust gas branch passage and the second exhaust gas branch passage, and controls the amount of exhaust gas flow to the first exhaust gas branch passage and the second exhaust gas branch passage. It may include a flow control means for.

Other details of implementations according to various aspects of the invention are included in the detailed description below.

According to the embodiment of the present invention, the flue gas introduced through the inclined flue gas inlet initially flows into the potting part, and then changes direction in the potting part and flows in the opposite direction, so that it is possible to increase the flow time in the humidification module. It becomes possible to improve the humidification efficiency.

In addition, the exhaust gas flows in from both directions through the inclined type exhaust gas inlets provided on both sides of the mid-case, respectively, and the exhaust gas introduced from both directions flows in the direction of the exhaust gas outlet formed in the center to be transmitted through the hollow fiber membrane. Since it is possible to minimize the reduction in the concentration of the material, it is possible to improve the overall fuel cell efficiency.

1 is a view showing a fuel cell membrane humidifier according to the prior art and a fuel cell system including the same.
2 is a diagram illustrating a fuel cell membrane humidifier and a fuel cell system including the same according to an embodiment of the present invention.
3 is a diagram conceptually illustrating an exhaust gas flow in a fuel cell membrane humidifier according to an embodiment of the present invention.

Since the present invention can apply various transformations and can have various embodiments, specific embodiments are illustrated and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

The terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present invention, terms such as 'comprise' or 'have' are intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, and one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof. Hereinafter, a fuel cell membrane humidifier and a fuel cell system including the same according to an embodiment of the present invention will be described with reference to the drawings.

2 is a view showing a fuel cell membrane humidifier and a fuel cell system including the same according to an embodiment of the present invention.

2, the fuel cell membrane humidifier and the fuel cell system including the same according to an embodiment of the present invention include a blower (B) and a fuel cell membrane humidifier (100, hereinafter also referred to as a 'membrane humidifier') and a fuel cell stack S and flow paths P10 , P20 , P30 , and P40 connecting them.

The blower (B) collects gas in the atmosphere and supplies it to the membrane humidifier 100 . The output size of the blower (B) may be determined according to the output size of the fuel cell stack (S). Optionally, a filter (not shown) for removing fine dust may be installed at the front end of the blower (B), and between the blower (B) and the membrane humidifier 100, dry gas supplied to the membrane humidifier 100 A cooler (not shown) may be installed to cool the .

The membrane humidifier 100 humidifies the dry gas and supplies it to the fuel cell stack (S). The membrane humidifier 100 includes a humidification module 110 for humidifying the dry gas supplied from the blower (B) with moisture in the exhaust gas discharged from the fuel cell stack (S). Each of both ends of the humidification module 110 is coupled to the caps (120, 130). The humidification module 110 and the caps 120 and 130 may be formed separately or may be formed integrally.

A drying gas inlet 121 is formed in the cap 120 on the side of the blower (B) to supply the drying gas supplied from the blower (B) to the humidification module 110, and the cap 130 on the side of the stack (S) has The dry gas outlet 131 is formed to supply the gas humidified by the humidification module 110 to the fuel cell stack S.

The dry gas inlet 121 is connected to the dry gas supply passage P10 connecting the blower B and the membrane humidifier 100, and the dry gas outlet 131 is a cap 130 on the fuel cell stack (S) side. It is connected to the humidification gas supply passage P20 connecting the fuel cell stack S and the fuel cell stack S.

The humidification module 110 is a device in which moisture exchange occurs between the dry gas supplied from the blower (B) and the exhaust gas, and a mid-case having a pair of inclined exhaust gas inlets (111a1, 111a2) and an exhaust gas outlet (111b) (mid-case) 111 and a plurality of hollow fiber membranes 112 accommodated in the mid-case 111 . Both ends of the bundle of hollow fiber membranes 112 are fixed to the potting part 113 .

Alternatively, the humidification module 110 may include at least one cartridge including a plurality of hollow fiber membranes 112 and a potting part 113 for fixing them to each other, in this case, the hollow fiber membranes 112 . And the potting unit 113 may be formed in a separate cartridge case (not shown, referred to as "inner case"). In this case, the hollow fiber membranes 112 may be accommodated in the inner case, and the potting part 113 may be formed at the end of the inner case. When the humidification module 110 includes a cartridge, a resin layer for fixing the cartridge is formed between both ends of the cartridge and the mid-case 111, or it may further include a gasket assembly for airtight coupling through mechanical assembly. can

The mid-case 111 and the caps 120 and 130 may each independently be formed of a hard plastic or metal, and may have a circular or polygonal cross-section in the width direction. A circle includes an ellipse, and a polygon includes a polygon with rounded corners. For example, the rigid plastic may be polycarbonate, polyamide (PA), polyphthalamide (PPA), polypropylene (PP), or the like.

The hollow fiber membranes 112 may include polysulfone resin, polyethersulfone resin, sulfonated polysulfone resin, polyvinylidene fluoride (PVDF) resin, polyacrylonitrile (PAN) resin, polyimide resin, polyamideimide resin, It may include a polyester imide resin, or a polymer film formed of a mixture of at least two or more thereof, and the potting part 113 is formed by curing a liquid resin such as a liquid polyurethane resin through a casting method such as deep potting or centrifugal potting. can be

In the embodiment of the present invention, the inclined type exhaust gas inlet (111a1, 111a2) may be provided as a pair on both sides of the mid-case (111). The inclined exhaust gas inlets 111a1 and 111a2 may be provided on either side of the mid-case 111 in the longitudinal direction (left and right direction in the drawing) on either side of the mid-case 111, respectively. In addition, a pair of inclined exhaust gas inlets 111a1 and 111a2 are formed in a direction inclined at a predetermined angle with respect to one surface of the mid-case 111 .

More specifically, the inclined flue gas inlets 111a1 and 111a2 are formed so that the lower ends of the flue gas inlets 111a1 and 111a2 are inclined toward the potting part 113 so that the exhaust gas flows toward the potting part 113 .

As the inclined exhaust gas inlets 111a1 and 111a2 are formed to be inclined in the potting part 113 direction, the exhaust gas is introduced while forming an inclination in the potting part 113 direction. Therefore, the exhaust gas initially flows into the potting unit 113, and then is changed in the potting unit 113 and flows in the opposite direction, so that it is possible to increase the flow time in the humidification module 110, thereby improving the overall humidification efficiency. be able to do Of course, depending on the design, the exhaust gas inlet may be provided in a plurality of three or more.

The exhaust gas discharged from the fuel cell stack S is introduced into the membrane humidifier 100 through the exhaust gas supply passage P30 and the inclined exhaust gas inlets 111a1 and 111a2. The exhaust gas supply passage P30 is branched into a first exhaust gas branch passage P31 and a second exhaust gas branch passage P32. The exhaust gas discharged from the fuel cell stack (S) flows through the flue gas supply channel P30, the first flue gas branch channel P31, and the second flue gas branch channel P32, while a pair of inclined flue gas inlets 111a1, 111a2) respectively.

If necessary, between the first exhaust gas branch passage (P31) and the second branch exhaust gas passage (P32), a flow rate control means for adjusting the amount of exhaust gas flow to the first exhaust gas branch passage (P31) and the second exhaust gas branch passage (P32) 140 may be installed. The flow rate control means 140 may be, for example, a valve.

Meanwhile, the inner space of the mid-case 111 may be divided into a first space S1 and a second space S2 by the partition wall 114 . The partition wall 114 may prevent the exhaust gas flowing into the inclined first exhaust gas inlet 111a1 from flowing directly into the second exhaust gas inlet 111a2 by bypassing the hollow fiber membrane 112 without exchanging moisture.

In an embodiment of the present invention, the exhaust gas outlet 111b is connected to the exhaust gas discharge passage P40, and may be formed in one on the opposite side of the surface on which the inclined exhaust gas inlets 111a1 and 111a2 are formed. For example, when a pair of inclined exhaust gas inlets 111a1 and 111a2 are formed on the upper surface of the mid-case 111 , the exhaust gas outlet 111b may be formed on the lower surface of the mid-case 111 .

In addition, the exhaust gas outlet 111b may be formed between the partition walls 114 that partition the first space S1 and the second space S2 . When the exhaust gas outlet (111b) is formed in the first space (S1) or the second space (S2), the exhaust gas introduced into any one inclined type exhaust gas inlet (111a1 or 111a2) does not exchange moisture with the hollow fiber membrane (112). It can be directly discharged to the outside through the exhaust gas outlet (111b) without.

For example, when the exhaust gas outlet 111b is formed in the first space S1 in FIG. 2 , the exhaust gas introduced through the first exhaust gas branch passage P31 and the first inclined exhaust gas inlet 111a1 is the first space Water is not sufficiently exchanged in (S1), and may flow directly to the exhaust gas outlet (111b).

Therefore, the exhaust gas outlet 111b is preferably formed between the first space (S1) and the second space (S2). The exhaust gas outlet 111b is preferably formed between the partition walls 114 dividing the first space S1 and the second space S2.

Next, an exhaust gas flow in the fuel cell membrane humidifier according to an embodiment of the present invention will be described with reference to FIG. 3 . 3 is a diagram conceptually illustrating an exhaust gas flow in a fuel cell membrane humidifier according to an embodiment of the present invention. In FIG. 3, the exhaust gas flow is shown to flow while winding the outside of the hollow fiber membranes 112, but the exhaust gas flow also flows into the bundle made of the hollow fiber membranes 112, but for convenience of explanation, this is omitted. shown.

The exhaust gas discharged from the fuel cell stack (S) flows through the flue gas supply channel P30, the first flue gas branch channel P31, and the second flue gas branch channel P32, while a pair of inclined flue gas inlets 111a1, 111a2) respectively.

The exhaust gas introduced into the first flue gas branch passage P31 and the first inclined flue gas inlet 111a1 initially flows into the potting part 113 in the first space S1, and then the direction is changed in the potting part 113. The dry gas is humidified by exchanging moisture with the hollow fiber membrane 112 while flowing in the opposite direction. The exhaust gas introduced into the second flue gas branch passage P32 and the second inclined flue gas inlet 111a2 initially flows into the potting part 113 in the second space S2, and then the direction is changed in the potting part 113. The dry gas is humidified by exchanging moisture with the hollow fiber membrane 112 while flowing in the opposite direction.

The exhaust gas, which has been exchanged with water in the first space (S1) and the second space (S2), is formed between the first space (S1) and the second space (S2), the exhaust gas outlet (111b) and the exhaust gas discharge passage (P40) discharged to the outside through

According to the prior art, it takes a considerable amount of time to be introduced through the exhaust gas inlet (11aa) and discharged through the exhaust gas outlet (11ab), and as the exhaust gas flows from the exhaust gas inlet (11aa) side to the exhaust gas outlet (11ab) side, the hollow As the concentration of the material to be transmitted through the desert gradually decreases, the amount of the material transmitted through the hollow fiber membrane placed on the side of the exhaust gas outlet 11ab also decreases gradually.

According to an embodiment of the present invention, the exhaust gas initially flows to the potting unit 113 and then is changed in the potting unit 113 to flow in the opposite direction, so that the flow time in the humidification module 110 can be increased. Thus, it becomes possible to improve the humidification efficiency as a whole.

In addition, the exhaust gas is introduced from both directions through the inclined exhaust gas inlet (111a1, 111a2) provided on both sides of the mid-case 111, respectively, and the exhaust gas introduced from both directions is formed in the center of the exhaust gas outlet (111b) As the flow in the direction of flow, it is possible to minimize the decrease in the concentration of the material to be transmitted through the hollow fiber membrane, thereby improving the overall efficiency of the fuel cell.

Above, an embodiment of the present invention has been described, but those of ordinary skill in the art can add, change, delete or add components within the scope that does not depart from the spirit of the present invention described in the claims. The present invention may be variously modified and changed by such as, and it will be said that it is also included within the scope of the present invention.

100: fuel cell membrane humidifier 110: humidification module
111: mid-case 112: hollow fiber membrane
113: potting unit 114: bulkhead
111a1, 111a2: inclined flue gas inlet 111b: flue gas outlet
B : Blower S : Fuel cell stack
P10: Dry gas supply passage P20: Humidifying gas supply passage
P30: flue gas supply flow path P31: first flue gas branch flow path
P32: 2nd flue gas branch flow path P40: flue gas discharge flow path

Claims (10)

mid-case;
The exhaust gas discharged from the fuel cell stack is introduced, and a first inclined exhaust gas inlet formed in a direction inclined at a predetermined angle on one side of one side of the mid-case, and one side of the mid-case inclined at a predetermined angle on the other side of the mid-case a second inclined type exhaust gas inlet formed in the direction; and,
one exhaust gas outlet formed on the other surface of the mid-case;
A fuel cell membrane humidifier comprising a.
The method according to claim 1,
and a partition wall dividing the inner space of the mid-case into a first space and a second space,
The first exhaust gas inlet is formed in the first space, and the second exhaust gas inlet is formed in the second space.
The method according to claim 2, The exhaust gas outlet,
A fuel cell membrane humidifier formed between the first space and the second space.
The method according to claim 2, The exhaust gas outlet,
A fuel cell membrane humidifier formed between the partition wall dividing the first space and the second space.
Blower for supplying dry gas;
fuel cell stack; and,
The mid-case, the exhaust gas discharged from the fuel cell stack is introduced, and a first inclined type exhaust gas inlet formed in a direction inclined at a predetermined angle on one side of one side of the mid-case; a fuel cell membrane humidifier including a second inclined exhaust gas inlet formed in an angled direction and one exhaust gas outlet formed on the other surface of the mid-case;
A fuel cell system comprising a.
6. The method of claim 5,
and a partition wall dividing the inner space of the mid-case into a first space and a second space,
The first exhaust gas inlet is formed in the first space, and the second exhaust gas inlet is formed in the second space.
The method according to claim 6, The exhaust gas outlet,
A fuel cell system formed between the first space and the second space.
The method according to claim 6, The exhaust gas outlet,
A fuel cell system formed between a partition wall dividing the first space and the second space.
6. The method of claim 5,
a humidification gas supply passage for supplying the gas humidified in the fuel cell membrane humidifier to the fuel cell stack;
an exhaust gas supply passage for supplying the exhaust gas discharged from the fuel cell stack to the fuel cell membrane humidifier;
a first exhaust gas branching passage branched from the exhaust gas supply passage and connected to the first exhaust gas inlet and a second exhaust gas branching passage connected to the second exhaust gas inlet;
A fuel cell system comprising a.
10. The method of claim 9,
and a flow rate control means formed between the first branch exhaust gas flow path and the second branch exhaust gas flow passage, and configured to adjust an exhaust gas flow amount to the first branch exhaust gas flow passage and the second branch exhaust gas flow passage.

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