Patent Description:
A fuel cell is a power generation cell that combines hydrogen and oxygen to generate electricity. Such a fuel cell has advantages in that it is possible to continuously generate electricity as long as hydrogen and oxygen are supplied, unlike a general chemical cell, such as a dry cell or a storage cell, and in that there is no heat loss, whereby efficiency of the fuel cell is about twice as high as efficiency of an internal combustion engine.

In addition, the fuel cell directly converts chemical energy generated by combination of hydrogen and oxygen into electrical energy, whereby the amount of contaminants that are discharged is small. Consequently, the fuel cell has advantages in that the fuel cell is environmentally friendly and in that a concern about depletion of resources due to an increase in energy consumption can be reduced.

Based on the kind of an electrolyte that is used, such a fuel cell may be classified as a polymer electrolyte membrane fuel cell (PEMFC), a phosphoric acid fuel cell (PAFC), a molten carbonate fuel cell (MCFC), a solid oxide fuel cell (SOFC), or an alkaline fuel cell (AFC).

These fuel cells are operated fundamentally by the same principle, but are different from each other in terms of the kind of fuel that is used, operating temperature, catalyst, and electrolyte. Among these fuel cells, the polymer electrolyte membrane fuel cell (PEMFC) is known as being the most favorable to a transportation system as well as small-scale stationary power generation equipment, since the polymer electrolyte membrane fuel cell is operated at a lower temperature than the other fuel cells and the output density of the polymer electrolyte membrane fuel cell is high, whereby it is possible to miniaturize the polymer electrolyte membrane fuel cell.

One of the most important factors that improve the performance of the polymer electrolyte membrane fuel cell (PEMFC) is to supply a predetermined amount or more of moisture to a polymer electrolyte membrane or a proton exchange membrane (PEM) of a membrane electrode assembly (MEA) in order to retain moisture content. The reason for this is that, in the case in which the polymer electrolyte membrane or the proton exchange membrane is dried, power generation efficiency is abruptly reduced.

Among these methods, the humidification membrane method, which provides water vapor to a gas that is supplied to the polymer electrolyte membrane or the proton exchange membrane using a membrane configured to selectively transmit only water vapor included in an exhaust gas in order to humidify the polymer electrolyte membrane or the proton exchange membrane, is advantageous in that it is possible to reduce the weight and size of a humidifier. Hollow fibre membrane humidifiers with a seal between the cap and the housing and the potting are known, e.g. from <CIT>, <CIT>.

In the case in which a module is formed, a hollow fiber membrane having large transmission area per unit volume is preferably used as the selective transmission membrane used in the humidification membrane method. That is, in the case in which a membrane humidifier is manufactured using a hollow fiber membrane, high integration of the hollow fiber membrane having large contact surface area is possible, whereby it is possible to sufficiently humidify a fuel cell even in the case of a small capacity, it is possible to use a low-priced material, and it is possible to collect moisture and heat included in a non-reaction gas discharged from the fuel cell at a high temperature and to reuse the collected moisture and heat through the humidifier.

Meanwhile, in a general membrane humidifier for a fuel cell, hollow fiber membranes are accommodated in a housing unit, and the hollow fiber membranes are adhered to the inner wall of the housing unit by a potting unit. The number of hollow fiber membranes accommodated in the housing unit is determined based on a desired output value of a stack, and the hollow fiber membranes are adhered and fixed to the housing unit by the potting unit. High-temperature air from a blower and high-temperature, high-humidity air from the stack are introduced into the membrane humidifier for a fuel cell. The coefficient of thermal expansion and the coefficient of thermal shrinkage of the potting unit are high, whereby a gap is formed between the housing unit and the potting unit and air leaks therethrough. In order to prevent this, a sealant is coated in the gap between the housing unit and the potting unit.

In the case in which air leaks, the air introduced from the blower leaks from the membrane humidifier for a fuel cell, whereby the amount of air that is introduced into the stack is reduced. For this reason, it is necessary for the blower to supply a larger amount of air than the amount of air actually necessary for the stack, whereby the power consumption of the blower is increased, which leads to system power loss. Consequently, maximum leakage prevention is advantageous in terms of overall power efficiency.

It is an object of the present disclosure to provide a membrane humidifier for a fuel cell capable of performing a hermetic sealing function in high-temperature/high-pressure/high-humidity environments through a mechanical assembly structure.

A membrane humidifier for a fuel cell according to the present disclosure includes a middle case accommodating a plurality of hollow fiber membranes, a cap case coupled to the middle case, a potting unit formed at ends of the plurality of hollow fiber membranes, an assembly member disposed between the cap case and an end of the middle case, the assembly member being configured to perform hermetic coupling therebetween, and a projection portion extending from the inside of the cap case toward the edge of the potting unit, the projection portion being configured to perform hermetic coupling between the cap case and the potting unit.

The cap case may include a large-diameter portion coupled to the middle case, the large-diameter portion having an inner diameter greater than the outer diameter of the potting unit, and a small-diameter portion protruding from a surface of the large-diameter portion, the small-diameter portion having an inner diameter less than the outer diameter of the potting unit.

The assembly member may include a main body disposed between the cap case and the end of the middle case, a first leg portion extending from the outer end of the main body in a longitudinal direction of the hollow fiber membranes so as to be in contact with the outer side surface of the end of the middle case, and a second leg portion extending from the inner end of the main body in the longitudinal direction of the hollow fiber membranes so as to be in contact with the inner side surface of the end of the middle case.

The assembly member may further include a filling portion filling an area between the projection portion of the cap case and the second leg portion.

The projection portion of the cap case may be formed so as to be in contact with the second leg portion.

The outer side surface of the end of the middle case may be provided with a step portion configured to receive the first leg portion.

The cap case may include a protrusion protruding from the surface thereof opposite the end of the middle case.

The projection portion may include an inclined surface formed at the inner side surface thereof, and the potting unit may include an inclined surface formed at the outer side surface thereof so as to press against the inclined surface of the projection portion.

A membrane humidifier for a fuel cell according to the present disclosure is capable of performing a hermetic sealing function in high-temperature/high-pressure/high-humidity environments through a mechanical assembly structure.

In addition, a mechanical sealing method is used instead of a chemical sealing method, whereby it is possible to omit a polyurethane/sealant coating and curing process necessary for a conventional chemical sealing method, and therefore it is possible to shorten working time, to improve work efficiency, and to construct a mass production system.

In addition, when unit cartridges disposed in the membrane humidifier are defective, reworkability is excellent, whereby it is possible to reduce a part scrap rate.

In addition, the membrane humidifier may be disassembled, only defective cartridges may be replaced, and then the membrane humidifier may be reassembled, whereby the present disclosure is advantageous in terms of reworkability and reuse of parts.

Furthermore, it is possible to simultaneously perform hermetic coupling between two or more parts through assembly members and projecting portions of cap cases, whereby manufacture and assembly are very convenient and efficient.

The present disclosure may be changed in various manners and may have various embodiments, wherein specific embodiments will be illustrated and described in detail in the following detailed description. However, the present disclosure is not limited to the specific embodiments, and it should be understood that the present disclosure includes all modifications, equivalents, or substitutions included in the idea and technical scope of the present disclosure.

The terms used in the present disclosure are provided only to describe the specific embodiments, and do not limit the present disclosure. Singular forms are intended to include plural forms as well, unless the context clearly indicates otherwise. In the present disclosure, it should be understood that the terms "includes," "has," etc. specify the presence of features, numbers, steps, operations, elements, components, or combinations thereof described in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, components, or combinations thereof. Hereinafter, a membrane humidifier for a fuel cell according to an embodiment of the present disclosure will be described with reference to the accompanying drawings.

<FIG> and <FIG> are exploded perspective views showing a membrane humidifier for a fuel cell according to an embodiment of the present disclosure. As shown in <FIG> and <FIG>, the membrane humidifier for a fuel cell according to the embodiment of the present disclosure includes a middle case <NUM>, cap cases <NUM>, potting units <NUM>, and assembly members <NUM>.

The middle case <NUM> is coupled to the cap cases <NUM> to define the external appearance of the membrane humidifier. Each of the middle case <NUM> and the cap cases <NUM> may be made of hard plastic, such as polycarbonate, or metal. The lateral sectional shape of each of the middle case <NUM> and the cap cases <NUM> may be a circle, as shown in <FIG>, or the lateral sectional shape thereof may be a polygon, as shown in <FIG>. The polygon may be a rectangle, a square, a trapezoid, a parallelogram, a pentagon, or a hexagon, and corners of the polygon may be round. In addition, the circle may be an oval. The middle case <NUM> is provided with a second fluid inlet <NUM>, through which a second fluid is introduced, and a second fluid outlet <NUM>, through which the second fluid is discharged. Alternatively, reference numeral <NUM> may indicate the second fluid inlet, and reference numeral <NUM> may indicate the second fluid outlet.

A hollow fiber membrane module, in which a plurality of hollow fiber membranes is accommodated, is disposed in the middle case <NUM>. The hollow fiber membrane module may include a hollow fiber membrane bundle comprising a plurality of integrated hollow fiber membranes or a plurality of hollow fiber membrane cartridges <NUM> (see <FIG>), in each of which hollow fiber membranes are accommodated. The drawings illustrate the case in which the hollow fiber membrane module includes hollow fiber membrane cartridges <NUM>; however, the case in which the hollow fiber membrane module includes a hollow fiber membrane bundle is not excluded.

The cap cases <NUM> are coupled to opposite ends of the middle case <NUM>. The cap cases <NUM> are provided with fluid introduction and discharge ports <NUM>, one of which is a first fluid inlet and the other of which is a first fluid outlet. A first fluid introduced through the fluid introduction and discharge port <NUM> of one of the cap cases <NUM> passes through an inner pipeline of each of the hollow fiber membranes accommodated in each of the hollow fiber membrane cartridges <NUM> and is then discharged outside through the fluid introduction and discharge port <NUM> of the other cap case <NUM>. Each hollow fiber membrane may be a hollow fiber membrane made of, for example, Nafion, polyetherimide, polyimide (PI), polyphenylsulfone, polysulfone (PS), or polyethersulfone (PES).

In the case in which the hollow fiber membrane module includes a plurality of hollow fiber membrane cartridges <NUM>, the hollow fiber membrane cartridges <NUM> may be provided at one side thereof with a first mesh unit <NUM> configured to allow the second fluid introduced into the membrane humidifier through the second fluid inlet <NUM> to be introduced into the hollow fiber membrane cartridges <NUM> therethrough, and may be provided at the other side thereof with a second mesh unit (not shown) configured to allow the second fluid that has performed moisture exchange in the hollow fiber membrane cartridges <NUM> to be discharged from the hollow fiber membrane cartridges <NUM> therethrough.

The hollow fiber membrane bundle or the hollow fiber membrane cartridges <NUM> are provided at opposite ends thereof with potting units <NUM> configured to bind the hollow fiber membranes and to fill the gaps between the hollow fiber membranes. As a result, the opposite ends of the hollow fiber membrane module are blocked by the potting units <NUM>, whereby a flow channel configured to allow the second fluid to pass therethrough is defined in the hollow fiber membrane module. Each of the potting units <NUM> is made of a known material, and a detailed description thereof will be omitted from this specification.

<FIG> is a sectional view showing a membrane humidifier according to a first embodiment of the present disclosure, <FIG> is a perspective view showing a hollow fiber membrane cartridge according to an embodiment of the present disclosure, and <FIG> is a perspective view showing an assembly member according to an embodiment of the present disclosure.

Hereinafter, embodiments in which a hollow fiber membrane module includes a hollow fiber membrane cartridge <NUM> will be shown and described. In addition, only a single hollow fiber membrane cartridge <NUM> is shown in the drawings; however, the case in which a plurality of hollow fiber membrane cartridges <NUM> is included in the membrane humidifier is not excluded.

The hollow fiber membrane cartridge <NUM> of <FIG> is one of a plurality of cartridges disposed in the case of the membrane humidifier. <FIG> shows an assembly member in the case in which a single cartridge and potting units are provided, wherein the shown assembly member <NUM> is generally configured so as to have a structure in which a pair of linear portions opposite each other is connected to a pair of semicircular portions opposite each other. <FIG> is a perspective view when viewed from the side at which the assembly member contacts a corresponding one of the cap cases <NUM>, and <FIG> is a perspective view when viewed from the opposite side.

The inner surface of the cap case <NUM> is assembled so as to be spaced apart from the end <NUM> of the middle case <NUM> by the assembly member <NUM>. In addition, the inner surface of the cap case <NUM> is assembled so as to be spaced apart also from the potting unit <NUM>.

In addition, according to the invention, the outer surfaces of the potting unit <NUM> and cartridge <NUM> are spaced apart from the inner surface of the middle case <NUM>. Consequently, the second fluid flows to the space between the potting unit <NUM> and the middle case <NUM>.

The middle case <NUM> and the cap case <NUM> are assembled using various fastening methods (not shown), such as fastening using a plurality of bolts, pressing, welding, and clamping. At this time, assembly is performed such that the assembly member <NUM> is inserted into the gap between the middle case and the cap case and is then pressed. <FIG> and the following figures are sectional views taken along planes that do not pass through fastening units, such as bolts, and therefore fastening units, such as bolts, are not shown.

As previously described, each of the middle case <NUM> and the cap case <NUM> may have a polygonal or circular section. The sectional views of <FIG> and the following figures show the case in which each of the middle case <NUM> and the cap case <NUM> has a quadrangular section.

The cap case <NUM> may include a large-diameter portion <NUM> coupled to the middle case <NUM>, the large-diameter portion having an inner diameter L1 greater than the outer diameter L3 of the potting unit <NUM>, and a small-diameter portion <NUM> protruding from a surface of the large-diameter portion <NUM>, the small-diameter portion having an inner diameter L2 less than the outer diameter L3 of the potting unit <NUM>.

Here, the outer diameter, the inner diameter, the large-diameter portion, and the small-diameter portion are generally terms related to the diameter of a circular pipe; however, the cases in which a housing of the membrane humidifier is circular, oval, and polygonal are all included.

Particularly, in the case in which the housing of the membrane humidifier is polygonal, the distance L2 between opposite inner surfaces of the small-diameter portion <NUM> of the cap case <NUM>, in which the fluid introduction and discharge port <NUM> is formed, is less than the distance L3 between opposite outer surfaces of the potting unit <NUM>. Consequently, the potting unit <NUM> may be pressed and fixed in the longitudinal direction by a projecting portion <NUM>, a description of which will follow. The shape of the cap case <NUM> may be applied to all of the following embodiments as well as the first embodiment without change.

In addition, the distance L3 between opposite outer surfaces of the potting unit <NUM> is less than the distance between opposite inner surfaces of the middle case <NUM>, whereby the potting unit <NUM> is disposed in the middle case <NUM> so as to be spaced apart therefrom. Consequently, the assembly member <NUM> is disposed between the middle case <NUM> and the potting unit <NUM> to fix the potting unit <NUM> such that the potting unit cannot move relative to the middle case <NUM>.

The assembly member <NUM> is disposed between the cap case <NUM> and the end of the middle case <NUM>, and is assembled so as to perform hermetic coupling therebetween. The cap case <NUM> includes a projecting portion <NUM> extending from the inside thereof toward the edge of the potting unit <NUM> so as to perform hermetic coupling between the cap case <NUM> and the potting unit <NUM>.

The assembly member <NUM> includes a main body <NUM> disposed between the cap case <NUM> and the end of the middle case <NUM>, a first leg portion <NUM> extending from the outer end of the main body <NUM> in the longitudinal direction of the hollow fiber membranes so as to be in contact with the outer side surface of the end <NUM> of the middle case <NUM>, and a second leg portion <NUM> extending from the inner end of the main body <NUM> in the longitudinal direction of the hollow fiber membranes so as to be in contact with the inner side surface of the end of the middle case <NUM>.

A pair of assembly members <NUM> is shown as being disposed in a horizontally symmetrical fashion in the sectional view of <FIG>; however, it will be understood that, in actuality, a single assembly member <NUM> is generally formed so as to have a quadrangular ring shape.

The main body <NUM> is disposed so as to be pressed by the inner surface of the cap case <NUM> and the end <NUM> of the middle case <NUM>.

The first leg portion <NUM> extends from the outer end of the main body <NUM> downwards, i.e. in the longitudinal direction of the hollow fiber membranes, based on <FIG>, and is disposed so as to be in contact with the outer side surface of the end <NUM> of the middle case <NUM>.

The second leg portion <NUM> extends from the inner end of the main body <NUM> downwards, i.e. in the longitudinal direction of the hollow fiber membranes, and is disposed so as to be in contact with the inner side surface of the end <NUM> of the middle case <NUM>.

As a result, a recess, into which the end of the middle case <NUM> is inserted, may be formed between the first leg portion <NUM> and the second leg portion <NUM>.

In addition, although the outer surface of the first leg portion <NUM> may be in contact with the inner surface of the cap case <NUM>, it is also possible that, as illustrated, they are not in contact with each other.

A step portion <NUM> configured to receive the first leg portion <NUM> may be provided at the outer side surface of the end <NUM> of the middle case <NUM>. As a result, the outer surface of the middle case <NUM> and the outer surface of the first leg portion <NUM> may form almost the same plane.

The projecting portion <NUM> extends from the inside of the cap case <NUM> toward the potting unit <NUM>, i.e. in the longitudinal direction of the hollow fiber membranes, and is formed so as to press against the edge of the potting unit <NUM>. The projecting portion <NUM> may extend by a length greater than the distance between the inner surface of the cap case <NUM> and a side surface of the potting unit <NUM>. In general, the potting unit <NUM> is made of a softer material than the cap case <NUM>. At the time of assembly, therefor, the potting unit <NUM> presses the cap case <NUM> such that the cap case is shrunk.

In <FIG>, the shape of the potting unit <NUM> before the edge of the potting unit is pressed by the projection portion <NUM> is shown in dotted lines. That is, according to the invention, when the potting unit <NUM> is pressed by the projecting portion <NUM>, the edge of the potting unit <NUM> is shrunk by a predetermined depth by the projection portion <NUM>, whereby hermetic coupling therebetween is achieved.

In the sectional view of <FIG>, the projection portion <NUM> is shown as being constituted by two members. In actuality, however, the projection portion <NUM> is formed integrally with the cap case <NUM>, and is formed so as to have the shape of a polygonal or circular rib. The outer surface of the projection portion <NUM> may be formed so as to have the same plane as the outer surfaces of the potting unit <NUM> and hollow fiber membrane cartridge <NUM>.

Preferably, the cap case <NUM> includes a protrusion <NUM> protruding from the surface thereof that is opposite the end <NUM> of the middle case <NUM>. The protrusion <NUM> may be formed in the shape of a rib having a semicircular section or any of various other shapes. In particular, the protrusion <NUM> serves to further press the main body <NUM> of the assembly member <NUM>, thereby improving hermetic sealing, and to fix the main body <NUM> such that the main body cannot move when pressed.

In the membrane humidifier according to the invention, the assembly member <NUM> may perform hermetic coupling between the end of the middle case and the cap case <NUM>, and at the same time the projection portion <NUM> of the cap case <NUM> performs hermetic coupling between the cap case <NUM> and the potting unit <NUM>.

<FIG> is a sectional view showing a membrane humidifier according to a second embodiment of the present disclosure. The membrane humidifier according to the second embodiment is different from the membrane humidifier according to the first embodiment in that the assembly member <NUM> further includes a filling portion <NUM> filling the area between the projection portion <NUM> of the cap case <NUM> and the second leg portion <NUM>.

As previously described, in the embodiments shown in <FIG>, according to the invention, a plurality of hollow fiber membranes are accommodated in a cartridge <NUM>, and the cartridge or a plurality of cartridges is/are disposed in the middle case <NUM>.

Since the inner surface of the cap case <NUM> and the potting unit <NUM> are disposed so as to be spaced apart from each other, as described above, the filling portion <NUM> is formed so as to fill the area between the projecting portion <NUM> of the cap case <NUM> and the second leg portion <NUM>. Consequently, it is possible to further prevent the second fluid introduced into the space between the inner surface of the cap case <NUM> and the cartridge <NUM> from leaking to the fluid introduction and discharge port <NUM> without passing through the hollow fiber membranes.

The vertical length of the filling portion <NUM> may be formed so as to be equal to the length of the projecting portion <NUM>, or may be formed so as to be equal to the length of the second leg portion <NUM>, as shown in <FIG>. Also, in <FIG>, the length of each of the first leg portion <NUM> and the second leg portion <NUM> is formed so as to be greater than the length of the projecting portion <NUM>. The length of each of the first leg portion <NUM> and the second leg portion <NUM> may be formed so as to be equal to the length of the projecting portion <NUM>. In this case, the vertical length of the filling portion <NUM> may be formed so as to be equal to the length of each of the second leg portion <NUM> and the projecting portion <NUM>.

The assembly member <NUM> is made of a soft material that has lower hardness than the cap case <NUM>. The width of the filling portion <NUM> may be formed so as to be slightly greater than the width between the inner surface of the second leg portion <NUM> and the outer surface of the projecting portion <NUM>, such that the filling portion can be shrunk by pressing at the time of assembly.

<FIG> is a sectional view showing a membrane humidifier according to a third embodiment of the present disclosure. The membrane humidifier according to the third embodiment is different from the membrane humidifier according to the first embodiment in that the projection portion <NUM> of the cap case <NUM> is formed so as to be in contact with the second leg portion <NUM>.

In the first embodiment, the outer surface of the projection portion <NUM> is formed so as to have the same plane as the outer surface of the potting unit <NUM>. In the third embodiment, however, the projection portion <NUM> is formed so as to have an increased thickness in the leftward-rightward direction such that the outer surface of the projection portion is in contact with the inner surface of the second leg portion <NUM> of the assembly member <NUM>.

As a result, the space between the inner surface of the projection portion <NUM> and the end <NUM> of the middle case <NUM> may be completely filled with the projection portion <NUM> and the assembly member <NUM>. Consequently, it is possible to further prevent the second fluid introduced into the space between the inner surface of the cap case <NUM> and the cartridge <NUM> from leaking to the fluid introduction and discharge port <NUM> without passing through the hollow fiber membranes.

The vertical length of the projection portion <NUM> is formed so as to be less than the vertical length of the assembly member <NUM>. Alternatively, the projection portion may be formed so as to have the same length as the assembly member <NUM>.

In addition, the protrusion <NUM> formed on the inner surface of the cap case <NUM> presses the main body <NUM>, whereby the main body <NUM> may securely perform hermetic coupling between the cap case <NUM> and the end <NUM> of the middle case <NUM>.

<FIG> is a sectional view showing a membrane humidifier according to a fourth embodiment of the present disclosure. The membrane humidifier according to the fourth embodiment is different from the membrane humidifier according to the first embodiment in that an inclined surface <NUM> is formed at the inner side surface of the projection portion <NUM> and an inclined surface <NUM> is formed at the outer side surface of the potting unit <NUM> so as to press against the inclined surface <NUM> of the projection portion <NUM>.

The inclined surface <NUM> is formed at the inner side surface of the projection portion <NUM>, and the inclined surface <NUM> is formed at the edge of the upper end of the potting unit <NUM>. At the time of assembly, the inclined surface <NUM> of the potting unit <NUM> is inserted inside the inclined surface <NUM> of the projection portion <NUM> while pressing against it, whereby the airtightness between the cap case <NUM> and the potting unit <NUM> may be improved.

Since the hardness of the cap case <NUM> is generally higher than the hardness of the potting unit <NUM>. As such, at the time of assembly, the inclined surface <NUM> of the projection portion <NUM> is pressed against the inclined surface <NUM> of the potting unit <NUM> such that the potting unit <NUM> shrinks.

Since the inclined surface of the projection portion <NUM> of the cap case <NUM> and the inclined surface of the potting unit <NUM> are pressed against each other, hermetic sealing performance may be improved more than in the other embodiments.

In addition, the inclined surface <NUM> may be formed only at the projection portion <NUM>, although both the inclined surface <NUM> of the projection portion <NUM> and the inclined surface <NUM> of the potting unit <NUM> may be formed. In this case, since the hardness of the projection portion <NUM> is higher than the hardness of the potting unit <NUM>, the inclined surface <NUM> of the projection portion <NUM> may press the edge of the potting unit <NUM> such that the potting unit is deformed to have an inclined surface.

<FIG> is a sectional view showing a membrane humidifier according to a fifth embodiment of the present disclosure. The membrane humidifier according to the fifth embodiment is different from the membrane humidifier according to the fourth embodiment in that the assembly member <NUM> further includes a filling portion <NUM> filling the area between the projection portion <NUM> of the cap case <NUM> and the second leg portion <NUM>.

The assembly member <NUM> is made of a soft material that has lower hardness than the cap case <NUM>. The width of the filling portion <NUM> may be formed so as to be slightly greater than the width between the inner surface of the second leg portion <NUM> and the outer surface of the projecting portion <NUM> such that the filling portion can be shrunk by pressing at the time of assembly.

<FIG> is a sectional view showing a membrane humidifier according to a sixth embodiment of the present disclosure. The membrane humidifier according to the sixth embodiment is different from the membrane humidifier according to the fourth embodiment in that the projection portion <NUM> of the cap case <NUM> is formed so as to be in contact with the second leg portion <NUM>.

In the fourth embodiment, the outer surface of the projection portion <NUM> is formed so as to have the same plane as the outer surface of the potting unit <NUM>. In the sixth embodiment, however, the projection portion <NUM> is formed so as to have an increased thickness in the leftward-rightward direction such that the outer surface of the projection portion is in contact with the inner surface of the second leg portion <NUM> of the assembly member <NUM>.

In addition, the membrane humidifier according to each of the fifth embodiment and the sixth embodiment is identical to the membrane humidifier according to the fourth embodiment in that the assembly member <NUM> includes a main body <NUM>, a first leg portion <NUM>, and a second leg portion <NUM>, the inner side surface of the projection portion <NUM> is formed as an inclined surface, and the protrusion <NUM> formed on the inner surface of the cap case <NUM>, i.e. the surface of the cap case that is opposite the end <NUM> of the middle case <NUM>, so as to protrude therefrom presses the main body <NUM>.

Although embodiments of the present disclosure have been described above, it will be apparent to a person having ordinary skill in the art to which the present disclosure pertains that the present disclosure can be variously modified and altered through addition, change, deletion, or supplement of components without departing from the idea of the present disclosure recited in the following claims and that such modifications and alterations fall within the scope of right of the present disclosure.

A membrane humidifier for a fuel cell including an assembly member according to each of various embodiments of the present disclosure is capable of performing a hermetic sealing function in high-temperature/highpressure/high-humidity environments through a mechanical assembly structure.

In addition, a mechanical sealing method is used instead of a chemical sealing method, whereby it is possible to omit a polyurethane/sealant coating and curing process necessary in a conventional chemical sealing method, and therefore it is possible to shorten working time, to improve work efficiency, and to construct a mass production system.

Claim 1:
A membrane humidifier for a fuel cell, the membrane humidifier comprising:
a middle case (<NUM>) accommodating a plurality of hollow fiber membranes; and
a cap case (<NUM>) coupled to the middle case (<NUM>);
a cartridge (<NUM>) disposed in the middle case (<NUM>), wherein the hollow fiber membranes are accommodated in the cartridge (<NUM>); and
a potting unit (<NUM>) provided at an end of the cartridge (<NUM>), wherein the potting unit (<NUM>) is formed at ends of the plurality of hollow fiber membranes and is configured to bind the hollow fiber membranes and to fill gaps between the hollow fiber membranes,
characterized in that: the membrane humidifier further comprises an assembly member (<NUM>) disposed between the cap case (<NUM>) and an end (<NUM>) of the middle case (<NUM>), the assembly member (<NUM>) being configured to perform hermetic coupling therebetween;
the cap case (<NUM>) includes a projection portion (<NUM>) extending from an inside of the cap case (<NUM>) toward an edge of the potting unit (<NUM>), the projection portion (<NUM>) being configured to perform hermetic coupling between the cap case (<NUM>) and the potting unit (<NUM>);
the assembly member (<NUM>) is made of a soft material that has lower hardness than the cap case (<NUM>) and, when assembled, is inserted into a gap between the cap case (<NUM>) and the end (<NUM>) of the middle case (<NUM>) and then pressed by the cap case (<NUM>) and the end (<NUM>) of the middle case (<NUM>) so as to perform hermetic coupling therebetween;
the potting unit (<NUM>) is pressed by the projection portion (<NUM>) and the edge of the potting unit (<NUM>) is shrunk by a predetermined depth by the projection portion (<NUM>), whereby the hermetic coupling between the cap case (<NUM>) and the potting unit (<NUM>) is achieved; and
an outer surface of the potting unit (<NUM>) and an outer surface of the cartridge (<NUM>) are spaced apart from an inner surface of the middle case (<NUM>).