Hollow fiber membrane cartridge, humidifier for fuel cell, and fuel cell containing the same

Abstract

The present invention relates to a hollow fiber membrane cartridge, a humidifier for a fuel cell, and a fuel cell including the same, which have excellent heat resistance and hydrolysis resistance, a heat distortion temperature of 120°C or higher, and a moisture absorption rate of 1% or less, so as to minimize deterioration of mechanical properties and dimensional deformation that may occur during use of the fuel cell and increase the durability life of the product.

Description

Technical Field

[0001] The present invention relates to a hollow fiber membrane cartridge, a fuel cell humidifier, and a fuel cell including the same, which are characterized by having heat resistance and hydrolysis resistance against a humidifying fluid at high temperature and high humidity.

Background Art

[0002] A fuel cell is a power generation type battery that combines hydrogen and oxygen to produce electricity. Different from general chemical batteries such as dry batteries and storage batteries, a fuel cell can continuously produce electricity as long as hydrogen and oxygen are supplied, has no heat loss, and has the advantage of being more efficient than an internal combustion engine. In addition, since the chemical energy generated by the combination of hydrogen and oxygen is directly converted into electrical energy, there is less emission of pollutants. Therefore, a fuel cell has the advantages of being environmentally friendly and being able to reduce the concern about resource depletion accompanying the increase in energy consumption. Among various types of fuel cells, a polymer electrolyte fuel cell (PEMFC) can operate at low temperature, has a large output density and can be miniaturized. Therefore, it is known not only as a small-scale stationary power generation device but also as a promising transportation system. One of the important factors in improving the performance of a polymer electrolyte fuel cell (PEMFC) is to supply a certain amount or more of moisture to the polymer electrolyte membrane (Polymer Electrolyte Membrane or Proton Exchange Membrane: PEM) of the membrane-electrode assembly (MEA) to maintain the water content rate. Humidification is required to maintain the water content rate. As the selective permeable membrane used for humidification, a hollow fiber membrane with a large permeable area per unit volume can be used. When manufacturing a humidifier using a hollow fiber membrane, it is possible to integrate a large number of hollow fiber membranes with a large contact surface area, which allows for sufficient humidification of the fuel cell even in small capacities, enables the use of low-cost materials, and has the advantage of recovering the moisture and heat contained in the exhaust gas (off-gas) discharged at high temperature from the fuel cell and reusing it through the humidifier. During the humidification process using the aforementioned hollow fiber membrane humidifier, the humidifier is exposed to high-temperature and high-humidity humidifying fluid. Therefore, the materials constituting the humidifier require heat resistance and hydrolysis resistance. Accordingly, there is a need to develop humidifier materials with excellent heat resistance and hydrolysis resistance. [Overview of the project] [Problems that the invention aims to solve]

[0003] One embodiment of the present invention was devised in consideration of the above-mentioned points, and aims to provide a hollow fiber membrane cartridge having excellent heat resistance. Another embodiment of the present invention aims to provide a hollow fiber membrane cartridge having excellent hydrolysis resistance. Another embodiment of the present invention aims to provide a hollow fiber membrane cartridge having excellent mechanical properties and dimensional stability. Another embodiment of the present invention aims to provide a humidifier for a fuel cell that includes the hollow fiber membrane cartridge described above. Another embodiment of the present invention aims to provide a fuel cell including a humidifier for fuel cells as described above. [Means for solving the problem]

[0004] To solve the aforementioned problems, embodiments of the present invention may include the following configurations. A hollow fiber membrane cartridge according to one embodiment of the present invention may include an inner case having an internal space, a plurality of hollow fiber membranes arranged in the internal space of the inner case, a first potting portion arranged on one side of the inner case and fixing one side of the plurality of hollow fiber membranes, and a second potting portion arranged on the other side of the inner case and fixing the other side of the plurality of hollow fiber membranes. The inner case may have a heat distortion temperature of 120°C or higher and a hygroscopicity of 1% or less. The inner case may have a moisture absorption rate of 0.5% or less. The inner case may contain a polymer resin. The polymer resin may contain at least one selected from polyphenylene ether (PPE), polyphenyl sulfone (PPSU), polysulfone (PSU), polyether ether ketone (PEEK), and polyarylate (PAR). The polyphenylene ether (PPE) may be a polyphenylene ether (m-PPE) modified with polystyrene-butadiene copolymer (HIPS). The m-PPE may contain 90-99% by weight of polyphenylene ether (PPE) and 1-10% by weight of polystyrene-butadiene copolymer (HIPS) relative to the total weight of the m-PPE. The inner case may have a weight reduction rate of 10% or less after high-temperature and high-humidity treatment. Here, the high-temperature and high-humidity treatment means placing the inner case inside an autoclave containing water, and then setting the autoclave to a temperature of 120°C ± 3°C and treating it for 200 hours. The aforementioned inner case is 100 x 10 -6 It can have a coefficient of thermal expansion (CTE) of mm / mm / °C or less. The aforementioned inner case has a specific gravity of 1.5 g / cm³. 3 The following is also acceptable. A humidifier for a fuel cell according to another embodiment of the present invention may include a mid-case having an internal space, an exhaust gas inlet and an exhaust gas outlet, the aforementioned hollow fiber membrane cartridge disposed in the internal space of the mid-case, a first cap coupled to one end of the mid-case, and a second cap coupled to the other end of the mid-case. A fuel cell according to yet another embodiment of the present invention may include a battery stack and a humidifier for the fuel cell connected to the battery stack. [Effects of the Invention]

[0005] A hollow fiber membrane cartridge according to one embodiment of the present invention can have excellent heat resistance and excellent hydrolysis resistance. Furthermore, the hollow fiber membrane cartridge according to one embodiment of the present invention can have excellent mechanical properties and dimensional stability. A fuel cell humidifier according to another embodiment of the present invention, including the hollow fiber membrane cartridge, can have excellent heat resistance, hydrolysis resistance, mechanical properties, and dimensional stability. A fuel cell according to another embodiment of the present invention, including the aforementioned humidifier for fuel cell, can have excellent heat resistance, hydrolysis resistance, mechanical properties, and dimensional stability. A fuel cell according to yet another embodiment of the present invention can have excellent durability and long lifespan, and can prevent or suppress problems such as breakage and failure. [Brief explanation of the drawing]

[0006] [Figure 1] This is a schematic perspective view of a hollow fiber membrane cartridge according to one embodiment of the present invention. [Figure 2] This is a perspective view of a hollow fiber membrane according to one embodiment of the present invention. [Figure 3] This is a schematic exploded perspective view of a fuel cell humidifier according to another embodiment of the present invention. [Modes for carrying out the invention]

[0007] The present invention can be modified in various ways and may have multiple embodiments, but below, a specific embodiment will be described in detail with reference to the attached drawings. Wherever "includes," "possesses," "performs," ​​etc., as used herein, other parts may be added unless the expression "only" is used. Where a component is expressed singularly, it includes multiple components unless otherwise explicitly stated. Furthermore, when interpreting a component, it shall be interpreted as including a margin of error, even without further explicit statement. The terms "First," "Second," etc., can be used to describe various components, but the components are not limited by the terms, and the terms are used solely for the purpose of distinguishing one component from another. Figure 1 is a schematic perspective view of a hollow fiber membrane cartridge (100) according to one embodiment of the present invention. Referring to Figure 1, a hollow fiber membrane cartridge (100) according to one embodiment of the present invention may include an inner case (110), a plurality of hollow fiber membranes (120), a first potting section (131), and a second potting section (132). The inner case (110) may have an internal space. The inner case (110) may have a box shape with both ends open. One of the open ends of the inner case (110) is called one side, and the other side is called the other side. Multiple hollow fiber membranes (120) can be arranged in the internal space of the inner case (110). Figure 2 is a perspective view of a hollow fiber membrane (120) according to one embodiment of the present invention. Referring to Figure 2, a hollow fiber membrane (120) according to one embodiment of the present invention may have a hollow (121). For example, the hollow fiber membrane (120) may have a tubular shape including an open center. A commercially available hollow fiber membrane can be used for the hollow fiber membrane (120). According to one embodiment of the present invention, one end of a tubular hollow fiber membrane (120) is referred to as one side, and the other end is referred to as the other side. The first potting section (131) is connected to one side of the inner case (110) and can fix one side of the multiple hollow fiber membranes (120). The second potting section (132) is connected to the other side of the inner case (110) and can fix the other side of the multiple hollow fiber membranes (120). Both ends of the hollow fiber membrane cartridge (100) are potted by a first potting section (131) and a second potting section (132). In this case, the first potting section (131) and the second potting section (132) can be formed so as not to block the hollows of the multiple hollow fiber membranes (120). The first potting section (131) and the second potting section (132) are generally formed by curing a liquid polymer such as liquid polyurethane (PU) resin using a casting method. An inner case (110) according to one embodiment of the present invention can have a heat distortion temperature of 120°C or higher.

[0008] The thermal distortion temperature can be measured using a test specimen of the inner case (110). The test specimen of the inner case (110) is, for example, a test specimen made from the material used for the inner case. Hereinafter, the test specimen of the inner case (110) will also be referred to as the "test specimen". According to one embodiment of the present invention, the heat distortion temperature can be measured by ASTM D 648. For measuring the heat distortion temperature, a test specimen with a thickness of 4 mm and in an unannealed (unheat-treated) state is prepared. A pressure stress of 1.8 MPa is applied to the test specimen while increasing the temperature from room temperature (25°C) at a rate of 2°C / min, and the temperature at which the test specimen bends by 0.25 mm is defined as the heat distortion temperature. If the thermal deformation temperature of the inner case (110) is below 120°C, dimensional or morphological deformation may occur due to the high-temperature humidifying fluid. This may lead to problems such as delamination of the adhesive interface between the first potting portion (131) and the inner case (110) or between the second potting portion (132) and the inner case (110). The heat distortion temperature of the inner case (110) according to an embodiment of the present invention may be, for example, 140 °C or higher. More specifically, the heat distortion temperature of the inner case (110) according to an embodiment of the present invention may be 150 °C or higher, or may be 160 °C or higher. The inner case (110) according to an embodiment of the present invention can have a moisture absorption of 1% or less. The moisture absorption can be determined, for example, by measuring the amount of moisture absorbed by a test piece of the inner case (110) after immersing it in water at 23 °C for 24 hours according to ASTM D 570. The moisture absorption can be measured by the following formula 1.

Number

[0009] According to one embodiment of the present invention, the m-PPE may contain 90 to 99% by weight of polyphenylene ether (PPE) and 1 to 10% by weight of polystyrene-butadiene copolymer (HIPS) relative to the total weight of the m-PPE. If the polyphenylene ether (PPE) content is less than 90% by weight of the total weight of m-PPE, problems may arise with heat resistance or mechanical strength. If it exceeds 99% by weight, the specific gravity of polyphenylene ether (PPE) is too high, making it difficult for HIPS to exhibit its properties and potentially causing problems with moldability. According to one embodiment of the present invention, the m-PPE may have a Mw molecular weight (weight-average molecular weight) of 70,000 to 100,000. According to one embodiment of the present invention, the inner case (110) can have excellent hydrolysis resistance. If the inner case (110) is not hydrolysis resistant, the polymer constituting the inner case (110) may be hydrolyzed by the high-temperature and high-humidity humidifying fluid. This may cause a rapid deterioration of the mechanical properties of the inner case (110). As a result, problems such as delamination between the inner case (110) and the potting parts (131, 132) of the hollow fiber membrane cartridge (100) may occur. According to one embodiment of the present invention, the hydrolysis resistance of the inner case (110) can be evaluated by the weight loss rate of the inner case (110). An inner case (110) according to one embodiment of the present invention has excellent hydrolysis resistance and exhibits little to no weight loss even after high-temperature and high-humidity treatment. An inner case (110) according to one embodiment of the present invention can have a weight reduction rate (WR) of 10% or less. The weight loss rate (WR) can be measured by the following formula 2.

number

[0010] To evaluate the peeling characteristics, according to one embodiment of the present invention, after treating the hollow fiber membrane cartridge (100) at high temperature and high humidity, it is possible to check whether or not peeling occurs between the inner case (110) and the potting portion (131, 132). The hollow fiber membrane cartridge (100) can be treated at high temperature and high humidity using an autoclave. According to one embodiment of the present invention, the high-temperature and high-humidity treatment conditions for evaluating peeling characteristics are as follows: After placing the hollow fiber membrane cartridge (100) in an autoclave containing water, the autoclave is heated to 120°C ± 3°C and treated for 200 hours. According to one embodiment of the present invention, if separation or detachment occurs between the inner case (110) and the potting portion (131, 132), it is evaluated that delamination has occurred between the inner case (110) and the potting portion (131, 132). According to one embodiment of the present invention, even after high temperature and high humidity treatment, delamination does not occur between the inner case (110) and the potting portion (131, 132) of the hollow fiber membrane cartridge (100). According to one embodiment of the present invention, delamination between the inner case (110) and the potting parts (131, 132) does not occur, and failure or damage to the humidifier or fuel cell including the inner case (110) can be prevented. An inner case (110) according to one embodiment of the present invention is 100 × 10 -6 It can have a coefficient of thermal expansion (CTE) of mm / mm / °C or less. The coefficient of thermal expansion can be measured, for example, using Thermomechanical Analysis (TMA) according to the TMA-Method and ASTM E 696. For Thermomechanical Analysis (TMA), for example, TA Instrument's Q400 can be used. The coefficient of thermal expansion is 100 × 10 -6 If the temperature exceeds mm / mm / °C, repeated temperature changes during use will increase the range of dimensional changes, and the resulting stress accumulation may cause the adhesive interface between the inner case (110) and the potting parts (131, 132) to peel off, or damage to the humidifier or fuel cell, including the inner case (110), leading to failure. An inner case (110) according to one embodiment of the present invention has a specific gravity of 1.5 g / cm³. 3 The following is also acceptable. The specific gravity of the inner case (110) can be measured, for example, according to ASTM D 792. The inner case (110) according to one embodiment of the present invention has a low specific gravity while possessing excellent mechanical properties, and can contribute to the lightweight design of products. Figure 3 is a schematic exploded perspective view of a fuel cell humidifier (200) according to another embodiment of the present invention. Referring to Figure 3, a humidifier for a fuel cell (200) according to another embodiment of the present invention may include a mid-case (210), a first cap (221), and a second cap (222).

[0011] The mid-case (210) may have an internal space. At least one or more hollow fiber membrane cartridges (100) can be placed in the internal space of the mid-case (210). The mid-case (210) may have a box shape with both ends open. One of the open ends of the mid-case (210) is called one end, and the other end is called the other end. A first cap (221) can be attached to one end of the mid-case (210). A second cap (222) can be attached to the other end of the mid-case (210). The resin layer (213) can be positioned between the midcase (210) and the hollow fiber membrane cartridge (100) so that the hollow fiber membrane cartridge (100) is fixed to the midcase (210). For example, the resin layer (213) can be positioned at one end and the other end of the midcase (210). One space can be created by the first cap (221) and the resin layer (213), and another space can be created by the second cap (222) and the resin layer (213). Yet another space can be created by the resin layer (213) located at one end of the midcase (210) and the resin layer (213) located at the other end of the midcase (210). The resin layer (213) can be placed in the internal space of the mid-case (210), for example, by a casting method. The resin layer (213) can be formed by curing a liquid polymer such as liquid polyurethane (PU) resin. The mid-case (210) may include an off-gas inlet (211) and an off-gas outlet (212). Exhaust gas flowing into the mid-case (210) through the off-gas inlet (211) can come into contact with the outer surfaces of the multiple hollow fiber membranes (120) and then be discharged from the mid-case (210) through the off-gas outlet (212). When the exhaust gas comes into contact with the outer surfaces of the multiple hollow fiber membranes (120), moisture contained in the exhaust gas permeates through the multiple hollow fiber membranes (120), thereby humidifying the air flowing along the hollows of the multiple hollow fiber membranes (120). Another embodiment of the present invention provides a fuel cell comprising a battery stack (not shown) and a fuel cell humidifier (200) connected to the battery stack. The present invention will be described below through more specific examples and comparative examples. However, the following examples are merely for the purpose of aiding understanding the present invention and do not limit the scope of the present invention.

[0012] <Example 1> (1) Manufacturing of the inner case (110) m-PPE (Mw molecular weight: 85,000), which contains polyphenylene ether (PPE) and polystyrene-butadiene copolymer (HIPS), was used as the polymer resin, and an inner case (110) having an internal space was manufactured by melting and molding this resin. (2) Manufacturing of hollow fiber membrane cartridge (100) A bundle was fabricated using hollow fiber membranes (120) and placed in the internal space of the inner case (110). Polyurethane (PU) was prepared for the formation of the first potting section (131) and the second potting section (132). A first potting section (131) is formed on one side of the inner case (110) using a casting method, and a second potting section (132) is formed on the other side of the inner case (110) so that the hollow fiber membrane (120) is fixed to the inner case (110). By this method, the hollow fiber membrane cartridge (100) according to Example 1 was manufactured. <Example 2> (1) Manufacturing of the inner case (110) An inner case (110) was manufactured using polyphenylsulfone (PPSU) instead of m-PPE, in the same manner as in Example 1 (1). (2) Manufacturing of hollow fiber membrane cartridge (100) A hollow fiber membrane cartridge (100) was manufactured in the same manner as in Example 1 (2), except that an inner case (110) made using polyphenylsulfone (PPSU) was used. <Example 3> (1) Manufacturing of the inner case (110) An inner case (110) was manufactured using polysulfone (PSU) instead of m-PPE, in the same manner as in Example 1 (1). (2) Manufacturing of hollow fiber membrane cartridge (100) A hollow fiber membrane cartridge (100) was manufactured in the same manner as in Example 1 (2), except that an inner case (110) made using polysulfone (PSU) was used. <Example 4> (1) Manufacturing of the inner case (110) An inner case (110) was manufactured using polyetheretherketone (PEEK) instead of m-PPE, in the same manner as in Example 1 (1). (2) Manufacturing of hollow fiber membrane cartridge (100) A hollow fiber membrane cartridge (100) was manufactured in the same manner as in Example 1 (2), except that an inner case (110) manufactured using polyetheretherketone (PEEK) was used.

[0013] <Example 5> (1) Manufacturing of the inner case (110) An inner case (110) was manufactured using polyarylate (PAR) instead of m-PPE, in the same manner as in Example 1 (1). (2) Manufacturing of hollow fiber membrane cartridge (100) A hollow fiber membrane cartridge (100) was manufactured in the same manner as in Example 1 (2), except that an inner case (110) made of polyarylate (PAR) was used. <Comparative Example> (1) Manufacturing of the inner case (110) An inner case (110) was manufactured using polycarbonate (PC) instead of m-PPE, in the same manner as in (1) of Example 1. (2) Manufacturing of hollow fiber membrane cartridge (100) A hollow fiber membrane cartridge (100) was manufactured in the same manner as in (2) of Example 1, except that an inner case (110) made of polycarbonate (PC) was used. The physical properties of the inner cases (110) and hollow fiber membrane cartridges (100) manufactured in Examples 1-5 and the Comparative Example were measured. The measurement method is as follows. <Heat Distortion Temperature (HDT) Measurement> 1) The heat distortion temperature of the inner cases (110) manufactured according to Examples 1 to 5 and the comparative examples was determined by supporting both ends of the test specimen in a heating bath, placing a rod on the center of the test specimen, applying a predetermined bending stress, and raising the temperature of the heating medium from room temperature (25°C) at a rate of 2°C / min, and measuring the temperature of the heating medium when the warpage of the test specimen reached a predetermined value. 2) More specifically, the heat distortion temperature of the inner cases (110) manufactured according to Examples 1-5 and the Comparative Example was measured according to ASTM D 648. For the measurement of the heat distortion temperature, test specimens according to Examples 1-5 and the Comparative Example were prepared with a thickness of 4 mm and in an unannealed (non-heat-treated) state. After placing them in a heated bath as described in 1), a pressure stress of 1.8 MPa was applied to the test specimen while increasing the temperature of the heating medium from room temperature (25°C) at a rate of 2°C / min. The temperature at which the test specimen warped by 0.25 mm was defined as the heat distortion temperature (HDT) and measured. <Hygroscopicity measurement> The hygroscopic properties of the inner cases (110) manufactured according to Examples 1-5 and the comparative examples were measured as follows. Test specimens of inner cases (110) manufactured according to Examples 1-5 and Comparative Examples were dried in a 50°C oven for 24 hours, then cooled in a desiccator. The weight after this drying was defined as the "initial specimen weight" and measured. The inner cases (110) test specimens with the initial weight were then immersed in 23°C water for 24 hours, removed, and the surface moisture was wiped off. The weight after this drying was defined as the "test specimen weight after moisture absorption" and measured. The "initial specimen weight" and the "test specimen weight after moisture absorption" were then compared, and the amount of moisture absorbed (adsorbed) by the inner cases (110) test specimens was measured according to ASTM D 570. The hygroscopicity of the inner cases (110) manufactured according to Examples 1-5 and the comparative examples was calculated using the following formula 1.

number

[0014] <Weight loss rate measurement> The weight loss rate (WR) of the inner cases (110) manufactured according to Examples 1-5 and the Comparative Example was measured by subjecting test specimens of the inner cases (110) manufactured according to Examples 1-5 and the Comparative Example to high temperature and high humidity using an autoclave. The high-temperature and high-humidity treatment conditions for measuring the weight loss rate (WR) are as follows: the test specimen of the inner case (110) is placed in an autoclave filled with water, and then the autoclave is heated to 120°C ± 3°C for 200 hours. The weight loss rate (WR) of the inner cases (110) manufactured according to Examples 1 to 5 and the comparative examples was calculated using the following formula 2.

number

[0015] <Specific gravity measurement> The specific gravity of the inner cases (110) manufactured according to Examples 1-5 and the Comparative Example was measured in accordance with ASTM D 792 using the water displacement method, which involves measuring the mass of each inner case (110) test specimen in air, then measuring the apparent mass when immersed in a liquid, and finally calculating the specific gravity. The measurement results are shown in Table 1 below. [Table 1] Referring to Table 1, it can be confirmed that the inner cases (110) and hollow fiber membrane cartridges (100) according to Examples 1 to 5 have excellent heat distortion temperatures, excellent hydrolysis resistance, low hygroscopicity, low thermal expansion coefficients, and low specific gravity. On the other hand, the inner cases (110) and hollow fiber membrane cartridges (100) according to the comparative examples have excellent thermal expansion coefficients and specific gravity, but can be confirmed to have low heat distortion temperatures and high hygroscopicity. In particular, after high-temperature and high-humidity treatment using an autoclave, the weight loss rate of the inner case (110) test specimen compared to the comparative example was as high as 40%. Furthermore, after high-temperature and high-humidity treatment using an autoclave, delamination appears between the inner case (110) and the potting portion (131, 132) in the comparative example hollow fiber membrane cartridge (100), confirming that it lacks sufficient hydrolysis resistance. The above description is merely illustrative of the technical concept of the present invention, and any person with ordinary skill in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Furthermore, the embodiments disclosed herein are for illustrative purposes only, not to limit the technical concept of the present invention, and these embodiments do not limit the scope of the technical concept of the present invention. Accordingly, the scope of protection of the present invention should be interpreted by the claims, and all technical concepts within an equivalent scope should be interpreted as being included within the scope of the rights of the present invention. [Explanation of symbols]

[0016] 100: Hollow fiber membrane cartridge 110: Inner case 120: Hollow fiber membrane 121: Hollow 131: First potting section 132: Second potting section 200: Humidifier for fuel cell 210: Mid-case 211: Exhaust gas inlet 212: Exhaust gas outlet 213: Resin layer 221: First cap 222: Second Cap

Claims

1. An inner case with an internal space; A plurality of hollow fiber membranes arranged in the internal space of the inner case; A first potting portion disposed on one side of the inner case and fixing one side of the plurality of hollow fiber membranes; and A second potting portion is disposed on the other side of the inner case and fixes the other side of the plurality of hollow fiber membranes; The aforementioned inner case contains a polymer resin, The aforementioned polymer resin contains at least one selected from polyphenylene ether (PPE), polyphenyl sulfone (PPSU), polyether ether ketone (PEEK), and polyarylate (PAR). The inner case has a heat distortion temperature of 120°C or higher and a hygroscopicity of 1% or less. Hollow fiber membrane cartridge.

2. The hollow fiber membrane cartridge according to claim 1, wherein the inner case has a hygroscopicity of 0.5% or less.

3. The hollow fiber membrane cartridge according to claim 1, wherein the polyphenylene ether (PPE) is a polyphenylene ether (m-PPE) modified with polystyrene-butadiene copolymer (HIPS).

4. The hollow fiber membrane cartridge according to claim 3, wherein the m-PPE comprises 90 to 99% by weight of polyphenylene ether (PPE) and 1 to 10% by weight of polystyrene-butadiene copolymer (HIPS) relative to the total weight of the m-PPE.

5. The hollow fiber membrane cartridge according to claim 1, wherein the inner case has a weight reduction rate of 10% or less after high temperature and high humidity treatment: Here, the high-temperature and high-humidity treatment means placing the inner case inside an autoclave containing water, and then setting the autoclave to a temperature of 120°C ± 3°C and treating it for 200 hours.

6. The aforementioned inner case is 100 x 10 -6 A hollow fiber membrane cartridge according to claim 1, having a coefficient of thermal expansion (CTE) of mm / mm / ℃ or less.

7. The aforementioned inner case has a specific gravity of 1.5 g / cm³. 3 The hollow fiber membrane cartridge according to claim 1, which is as follows:

8. A mid-case having an internal space, an exhaust gas inlet, and an exhaust gas outlet; A hollow fiber membrane cartridge according to any one of claims 1 to 7, disposed in the internal space of the mid-case; A first cap coupled to one end of the mid-case; and A fuel cell humidifier, including a second cap coupled to the other end of the mid-case.

9. Battery stack; and A fuel cell comprising a humidifier for a fuel cell according to claim 8, connected to the battery stack;

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