Hydrogen storage composition, hydrogen storage container and method for producing hydrogen storage container with hydrogen storage composition

Abstract

A hydrogen storage composition, a hydrogen storage container and a method for producing the hydrogen storage container are provided. The hydrogen storage composition includes a thermally-conductive material, a hydrogen storage material, and optionally a granular elastic material. The hydrogen storage container includes a canister body and the hydrogen storage composition. After the hydrogen storage composition is placed into a canister body, a vacuum environment within the canister body is created, and a first weight of the canister body is recorded. Then, hydrogen gas is charged into the canister body, and a second weight of the canister body is recorded. Then, a hydrogen storage amount is calculated according to the first weight and the second weight. If the hydrogen storage amount reaches the predetermined value, the hydrogen storage container is produced.

Claims

1. A hydrogen storage composition, comprising: a hydrogen storage material; a granular elastic material mixed with the hydrogen storage material and configured to alleviate a deformation that is resulted from a volume expansion or shrinkage of the hydrogen storage material; and a thermally-conductive material mixed with the hydrogen storage material and the granular elastic material and configured to conduct heat among the hydrogen storage material and alleviate a displacement of the granular elastic material relative to the hydrogen storage material, wherein each of the hydrogen storage material, the granular elastic material and the thermally-conductive material has the same physical and chemical properties as those before mixing and is removable from the hydrogen storage composition by sieving.

2. The hydrogen storage composition according to claim 1, wherein the hydrogen storage composition comprises 1 to 15 weight parts of the thermally-conductive material and 1 to 35 weight parts of the granular elastic material, based on a total of 100 weight parts of the hydrogen storage material, the granular elastic material and the thermally-conductive material.

3. The hydrogen storage composition according to claim 1, wherein the granular elastic material is an elastic resin, or a solid polymeric material selected from the group consisting of polyurethane, rubber, elastomer, poly (vinyl chloride), acrylonitrile-butadiene-styrene copolymer, high density polyethylene, low density polyethylene, polystyrene, polycarbonate, poly (methyl methacrylate), thermoplastic elastomer and polypropylene.

4. The hydrogen storage composition according to claim 1, wherein the granular elastic material includes a solid polymeric material having a deformation ratio higher than or equal to the deformation ratio of the hydrogen storage material.

5. The hydrogen storage composition according to claim 1, wherein the hydrogen storage material, the granular elastic material and the thermally-conductive material are separable by physical classification.

6. The hydrogen storage composition according to claim 1, wherein the thermally-conductive material is carbon, copper, titanium, zinc, iron, vanadium, chromium, manganese, cobalt, nickel or aluminum.

7. The hydrogen storage composition according to claim 1, wherein the thermally-conductive material has a length larger than a diameter of the granular elastic material, and the diameter of the granular elastic material is larger than a diameter of the hydrogen storage material.

8. A hydrogen storage container, comprising: a canister body; and a hydrogen storage composition contained in the canister body, wherein the hydrogen storage composition comprises a hydrogen storage material; a granular elastic material mixed with the hydrogen storage material and configured to alleviate a deformation that is resulted from a volume expansion or shrinkage of the hydrogen storage material; and a thermally-conductive material mixed with the hydrogen storage material and the granular elastic material and configured to conduct heat among the hydrogen storage material and alleviate a displacement of the granular elastic material relative to the hydrogen storage material, wherein each of the hydrogen storage material, the granular elastic material and the thermally-conductive material has the same physical and chemical properties as those before mixing and is removable from the hydrogen storage composition by sieving.

9. The hydrogen storage container according to claim 8, wherein the hydrogen storage composition comprises 1 to 15 weight parts of thermally-conductive material and 1 to 35 weight parts of the granular elastic material, based on a total of 100 weight parts of the hydrogen storage material, the granular elastic material and the thermally-conductive material.

10. The hydrogen storage container according to claim 8, wherein the granular elastic material is an elastic resin, or a solid polymeric material selected from the group consisting of polyurethane, rubber, elastomers, poly (vinyl chloride), acrylonitrile-butadiene-styrene copolymer, high density polyethylene, low density polyethylene, polystyrene, polycarbonate, poly (methyl methacrylate), thermoplastic elastomer and polypropylene.

11. The hydrogen storage container according to claim 8, wherein the granular elastic material includes a solid polymeric material having deformation ratio higher than or equal to the deformation ratio of the hydrogen storage material.

12. The hydrogen storage container according to claim 8, wherein the hydrogen storage material, the granular elastic material and the thermally-conductive material are separable by physical classification.

13. The hydrogen storage container according to claim 8, wherein the thermally-conductive material is carbon, copper, titanium, zinc, iron, vanadium, chromium, manganese, cobalt, nickel or aluminum.

14. The hydrogen storage container according to claim 8 wherein the thermally-conductive material has a length larger than a diameter of the granular elastic material, and the diameter of the granular elastic material is larger than a diameter of the hydrogen storage material.

15. A method for producing a hydrogen storage container, the method comprising steps of: (a) placing a hydrogen storage composition into a canister body, wherein the hydrogen storage composition comprises a hydrogen storage material, a granular elastic material mixed with the hydrogen storage material and configured to alleviate a deformation that is resulted from a volume expansion or shrinkage of the hydrogen storage material, and a thermally-conductive material mixed with the hydrogen storage material and the granular elastic material and configured to conduct heat among the hydrogen storage material and the canister body, and alleviate a displacement of the granular elastic material relative to the hydrogen storage material, wherein each of the hydrogen storage material, the granular elastic material and the thermally-conductive material has the same physical and chemical properties as those before mixing and is removable from the hydrogen storage composition by sieving; (b) creating a vacuum environment within the canister body, and recording a first weight of the canister body; (c) charging hydrogen gas into the canister body to activate the hydrogen the hydrogen storage material, and recording a second weight of the canister body; and (d) calculating a hydrogen storage amount according to the first weight and the second weight, and judging whether the hydrogen storage amount reaches a predetermined value, wherein if the hydrogen storage amount reaches the predetermined value, the hydrogen storage container is produced, wherein if the hydrogen storage amount does not reach the predetermined value, the steps (b), (c) and (d) are repeatedly done.

16. The method according to claim 15, wherein in the step (a), the hydrogen storage composition comprises 1 to 15 weight parts of thermally-conductive material and 1 to 35 weight parts of the granular elastic material, based on a total of 100 weight parts of the hydrogen storage material, the granular elastic material and the thermally-conductive material.

17. The method according to claim 15, wherein the hydrogen storage composition is prepared by steps of: mixing the thermally-conductive material and the granular elastic material in a pretreatment vessel; creating a vacuum environment within the pretreatment vessel; and adding the hydrogen storage material into the pretreatment vessel, so that the hydrogen storage composition is prepared.

18. The method according to claim 15, wherein after the thermally-conductive material and the granular elastic material are mixed in the pretreatment vessel, the pretreatment vessel is sealed and placed in a constant temperature environment at 60° C. or higher, and a vacuum pump is used to create the vacuum environment within the pretreatment vessel.

19. The method according to claim 15, wherein in the step (c), after the hydrogen storage composition is placed into a canister body, the canister body is sealed and placed in a constant temperature environment at 60° C. or higher, and a vacuum pump is used to create the vacuum environment within the canister body.

20. The method according to claim 15, wherein the step of charging hydrogen gas into the canister body is performed by placing the canister body in a hydrogen supply system at 5° C. to 20° C. and charging pure hydrogen gas into the canister body for at least one hour.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a detailed diagram of the hydrogen storage composition an embodiment of the present invention;

(2) FIG. 2 is a flowchart illustrating a process of forming and pretreating a hydrogen storage composition according to an embodiment of the present invention;

(3) FIG. 3 is a flowchart illustrating a method for producing a hydrogen storage container according to an embodiment of the present invention;

(4) FIG. 4 schematically illustrates some positions of measuring the deformation of the hydrogen storage container according to an embodiment of the present invention; and

(5) FIG. 5 is a plot illustrating the hydrogen desorption curves of four hydrogen storage compositions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(6) The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed.

(7) FIG. 1 shows a detailed diagram of the hydrogen storage composition an embodiment of the present invention. According to the present invention, a hydrogen storage composition 1 is provided. The hydrogen storage composition is filled in a canister body 30 of a hydrogen storage container 3 (see FIG. 4). In an embodiment, the hydrogen storage composition 1 comprises a hydrogen storage material 11, a granular elastic material 12 and a thermally-conductive material 13. The hydrogen storage material 11, the granular elastic material 12 and the thermally-conductive material 13 are mixed with each other by for example a physical mixing method. Namely, the hydrogen storage composition 1 is a mixture of pure separable states, wherein the hydrogen storage material 11, the granular elastic material 12 and the thermally-conductive material 13 are separable by physical classification. The granular elastic material 12 is optionally configured to alleviate a deformation that is resulted from a volume expansion or shrinkage of the hydrogen storage material 11. The thermally-conductive material 13 is configured to conduct heat among the hydrogen storage material 11 and the canister body 30, and alleviate a displacement of the granular elastic material 12 relative to the hydrogen storage material 11. In the embodiment, the diameter of the hydrogen storage material 11 can be for example ranged from 30 μm to 900 μm. For alleviating the deformation, the granular elastic material 12 can have an average diameter about 1000 μm to 3000 μm which is larger than that of the hydrogen storage material 11. In addition, for conducting the heat and alleviating the displacement, the thermally-conductive material 13 can be for example strip-like or needle-like and have the length for example ranged from 1500 μm to 9900 μm and the cross-sectional diameter ranged from 50 μm to 250 μm. It is noted that the length of the thermally-conductive material 13 is larger than the diameter of the granular elastic material 12. The weight fraction of the thermally-conductive material 13 is preferably 1 to 15 weight parts, more preferably 1 to 10 weight parts, and the most preferably 1 to 5 weight parts, based on a total of 100 weight parts of the thermally-conductive material 13, the hydrogen storage material 11 and the granular elastic material. In case that the fraction of the thermally-conductive material 13 is higher than 1 weight part, the thermally-conductive material 13 can conduct heat to the hydrogen storage material 11 and alleviate the displacement of the granular elastic material 12 relative to the hydrogen storage material 11. In case that the fraction of the thermally-conductive material 13 is lower than 30 weight part, the thermally-conductive material 13 can conduct heat to the hydrogen storage material 11 thoroughly in order to effectively heat or cool the hydrogen storage material 11. In the meantime, the displacement of the granular elastic material 12 relative to the hydrogen storage material 11 is alleviated. Consequently, the efficiency of charging/discharging hydrogen gas is increased and the durability and safety of the canister body 30 are enhanced. The fraction of the granular elastic material 12 is preferably 1 to 35 weight parts, more preferably 1 to 20 weight parts, and the most preferably 1 to 10 weight parts, based on a total of 100 weight parts of the thermally-conductive material 13, the hydrogen storage material 11 and the granular elastic material 12. In case that the fraction of the granular elastic material 12 is higher than 1 weight part, the granular elastic material 12 can alleviate the strain or deformation that is resulted from the volume expansion or shrinkage of the hydrogen storage material 11. In case that the fraction of the granular elastic material 12 is lower than 35 weight part, the fraction of the hydrogen storage material 11 is at least 50 weight parts in order to increase the hydrogen storage amount of the hydrogen storage container. It is noted that the fraction of the hydrogen storage material 11, the granular elastic material 12 and the thermally-conductive material 13 can be adjustable according to the practical requirements and obtain that an optimized packing density of the hydrogen storage composition 1, and not redundantly described herein.

(8) The cross section of the canister body 30 has a circular shape, an elliptic shape, a triangular shape, a square shape, a polygonal shape or an irregular shape. It is noted that the shape of the cross section of the canister body 30 is not restricted. In an embodiment, the canister body 30 is a cylinder-shaped canister body. Preferably but not exclusively, the hydrogen storage container 3 is made of a metallic material (e.g., steel or aluminum alloy) or a carbon fiber-reinforced composite material. Moreover, the container 3 is a gas storage canister or a hydrogen storage canister. The hydrogen storage container 3 is suitably used as a hydrogen gas source. Moreover, the hydrogen storage container 3 is applied to any electronic device using fuel cells. An example of the electronic device includes but is not limited to a mobile electric vehicle, a stationary power generator or a 3C product. The hydrogen storage container 3 has an accommodation space for accommodating the hydrogen storage composition 1 and storing the hydrogen gas.

(9) An example of optionally the thermally-conductive material 13 includes but is not limited to carbon, copper, titanium, zinc, iron, vanadium, chromium, manganese, cobalt, nickel or aluminum, an alloy wire, a fiber yarn, a needle-like structure or a strip: like structure of the above components, or any other appropriate thermally-conductive material 13 with thermal conductivity in the range between 90 W/mk and 500 W/mk. Due to the thermal conductivity of the alloy wire, the fiber yarn or the needle-type structure, the surface area of the thermally-conductive material 13 is effectively increased and the thermal conduction efficacy of the hydrogen storage material 11 is enhanced. Furthermore, the length of the thermally-conductive material 13 is larger than the diameter of the granular elastic material 12. It facilitates the thermally-conductive materials 13 to alleviate the displacement of the granular elastic material 12 relative to the hydrogen storage material 11 during the charging/discharging process.

(10) In the embodiment, the hydrogen storage material 11 is optionally a hydrogen storage alloy or a hydrogen storage nanomaterial. The hydrogen storage material 11 can absorb or desorb hydrogen gas at different operating temperatures and pressures in order to achieve the purpose of storing or releasing the hydrogen gas. In an embodiment, the hydrogen storage material 11 includes an AB alloy, an A2B alloy, an AB2 alloy, an AB5 alloy or a body-centered cubic (BCC) alloy. In the AB5 alloy, A is lanthanum (La) alone or the mixture of at least one rare earth element and lanthanum. Particularly, lanthanum (La) or a portion of lanthanum (La) is substituted by cerium (Ce), praseodymium (Pr), neodymium (Nd) or other rare-earth element. For example, A is a cerium-rich alloy (Mm). Moreover, B is iron (Fe), nickel (Ni), manganese (Mn), cobalt (Co) or aluminum (Al). In the AB2 alloy, A is titanium (Ti) or zirconium (Zr), B is manganese (Mn), chromium (Cr), vanadium (V) or iron (Fe), and the ratio of A to B is in the range between 1:1 and 1:2 (e.g., 1:2). For example, the AB alloy includes titanium-iron (TiFe) alloy or titanium-cobalt (TiCo) alloy, wherein the B component can be partially substituted by a variety of elements. For example, the A2B is magnesium-nickel alloy (Mg2Ni). The BCC alloy is a body-centered cubic alloy consisting of titanium (Ti), chromium (Cr), vanadium (V), molybdenum (Mo) and the like. Preferably, the hydrogen storage material includes but is not limited to lanthanum-nickel alloy series, iron-titanium alloy series or magnesium-nickel alloy series. In addition, the carbon nanomaterial is also suitably used as the hydrogen storage material 11.

(11) An example of optionally the granular elastic material 12 includes but is not limited to an elastic resin, or a solid polymeric material selected from the group consisting of polyurethane (PU), rubber, elastomer, poly vinyl chloride (PVC), acrylonitrile-butadiene-styrene copolymer (ABS copolymer), high density polyethylene (HDPE), low density polyethylene (LDPE), polystyrene (PS), polycarbonate (PC), poly (methyl methacrylate) (PMMA), thermoplastic elastomer (TPE) and polypropylene (PP). Preferably, the elastic material is polyurethane (PU). The granular elastic material 12 is used for alleviating the deformation of the hydrogen storage material 11 from volume expansion or shrinkage. More preferably, the granular elastic material 12 can be for example a PU granule. It is noted that the granular elastic material 12 is not limited to the above-mentioned materials. Preferably, the granular elastic material 12 includes a solid polymeric material having a deformation ratio higher than or equal to the deformation ratio of the hydrogen storage material 11. Consequently, the granular elastic material 12 can alleviate the strain or deformation that is resulted from the volume expansion or shrinkage of the hydrogen storage material 11.

(12) FIG. 2 is a flowchart illustrating a process of forming and pretreating a hydrogen storage composition according to an embodiment of the present invention. The structures, elements and functions of the hydrogen storage composition 1 are similar to those of the hydrogen storage composition 1 in FIG. 1, and are not redundantly described herein. In a step S11, a thermally-conductive material 13 and a granular elastic material 12 are mixed and placed into a pretreatment vessel (not shown), and then the pretreatment vessel is sealed. Consequently, the pretreatment vessel is in an airtight state. Then, in a step S12, a vacuum environment within the pretreatment vessel is created. For example, after the pretreatment vessel with the thermally-conductive material 13 and the granular elastic material 12 is placed in a constant temperature water tank and maintained at a constant temperature, a vacuum pump (not shown) is turned on to create the vacuum environment within the pretreatment vessel. Preferably but not exclusively, the constant temperature water tank is maintained at 60° C. or higher, and the vacuum pump is operated for at least one hour to create the vacuum environment within the pretreatment vessel. In a step S13, the thermally-conductive material 13 and the granular elastic material 12 are removed from the pretreatment vessel and mixed with a hydrogen storage material 11, and the thermally-conductive material 13, the granular elastic material 12 and the hydrogen storage material 11 are stirred for a specified time period (e.g., the stirring time includes but is not limited to 5 minutes) and uniformly mixed. Consequently, the process of forming and pretreating the hydrogen storage composition 1 is completed.

(13) FIG. 3 is a flowchart illustrating a method for producing a hydrogen storage container according to an embodiment of the present invention. Firstly, in a step S21, the hydrogen storage composition 1 is placed into a canister body 30. In an embodiment, the hydrogen storage composition 1 (see FIG. 1) comprises a thermally-conductive material 13, a hydrogen storage material 11 and a granular elastic material 12 in a specified weight ratio. The fraction of the thermally-conductive material 13 is preferably 1 to 15 weight parts, and the fraction of the granular elastic material 12 is preferably 1 to 35 weight parts, based on a total of 100 weight parts of the thermally-conductive material 13, the hydrogen storage material 11 and the granular elastic material 12. Optionally, the step S21 further comprises a sub-step of pretreating the hydrogen storage composition 1. The way of pretreating the hydrogen storage composition 1 is similar to the flowchart of FIG. 2. That is, after the thermally-conductive material 13 and the granular elastic material 12 are mixed in the pretreatment vessel, a vacuum environment within the pretreatment vessel is created. Then, the hydrogen storage material 11 is added and uniformed mixed with the thermally-conductive material 13 and the granular elastic material 12, and thus the hydrogen storage composition 1 is formed. After the hydrogen storage composition 1 is formed and placed into a canister body 30, the canister body 30 is sealed. Consequently, the canister body 30 is in an airtight state.

(14) Then, in a step S22, a vacuum environment within the canister body 30 is created, and the weight of the canister body 30 is recorded. The weight of the canister body 30 indicates the weight of the canister body 30 before the canister body 30 is charged with hydrogen gas. In an embodiment of the step S22, after the canister body 30 is in the airtight state, the canister body 30 is placed in a constant temperature water tank and maintained at a constant temperature, and a vacuum pump (not shown) is turned on to create the vacuum environment within the canister body 30. Preferably but not exclusively, the constant temperature water tank is maintained at 60° C. or higher.

(15) Then, in a step S23, hydrogen gas is charged into the canister body 30 to activate the hydrogen storage material 11, and the weight of the canister body 30 is recorded. The weight of the canister body 30 indicates the weight of the canister body 30 after the canister body 30 is charged with hydrogen gas. In an embodiment, for charging hydrogen gas into the canister body 30, the canister body 30 is placed in a hydrogen supply system with cold water circulation (5° C.˜20° C.) and pure hydrogen gas is charged into the canister body 30 at a pressure of 1 MPa for at least one hour. The process of charging hydrogen gas into the canister body may be varied according to the practical requirements.

(16) Then, in a step S24, a hydrogen storage amount is calculated according to the result of comparing the weight of the canister body 30 before charged with hydrogen gas and the weight of the canister body 30 after charged with hydrogen gas. Then, a step S25 is performed to judge whether the hydrogen storage amount reaches a predetermined value. If the judging condition of the step S25 is satisfied, it means that the hydrogen storage container is produced. Whereas, if the judging condition of the step S25 is not satisfied, the above steps are repeatedly done until the hydrogen storage amount reaches the predetermined value. It is noted that the hydrogen storage material 11, the granular elastic material 12 and the thermally-conductive material 13 are directly mixed with each other by a physical mixing method. The granular elastic material 12 is not further heated for curing or forming a fixed block. It is noted that the hydrogen storage composition 1 is a mixture of pure separable states. The hydrogen storage material 11, the granular elastic material 12 and the thermally-conductive material 13 are separable by physical classification. Namely, the hydrogen storage composition 1 is reworkable. While the relative ratio of the hydrogen storage composition 1 has to be adjusted, the hydrogen storage container 3 with the hydrogen storage composition 1 can be reworked easily.

(17) The present invention will be further understood in more details with reference to the following examples.

(18) Four formulations of the hydrogen storage compositions 1 are prepared by mixing different amounts of thermally-conductive material 13 (e.g., aluminum fiber), a fixed amount of granular elastic material 12 (e.g., PU granule) and a fixed amount of hydrogen storage material 11. After 50 grams of thermally-conductive material 13, 70 grams of granular elastic material 12 and 3000 grams of hydrogen storage material 11 are mixed, a formulation A is prepared. After 100 grams of thermally-conductive material 13, 70 grams of granular elastic material 12 and 3000 grams of hydrogen storage material 11 are mixed, a formulation B is prepared. After 150 grams of thermally-conductive material 13, 70 grams of granular elastic material 12 and 3000 grams of hydrogen storage material 11 are mixed, a formulation C is prepared. After 200 grams of thermally-conductive material 13, 70 grams of granular elastic material 12 and 3000 grams of hydrogen storage material 11 are mixed, a formulation D is prepared. Then, the hydrogen storage compositions 1 with the formulations A, B, C and D are placed into four different canister bodies 30, respectively. After the subsequent hydrogen activating process and measuring process, four hydrogen storage containers 3 are produced. In addition, some experimental data are acquired for comparison.

(19) Pretreatment of Hydrogen Storage Composition

(20) Firstly, 50 grams of thermally-conductive material 13 and 70 grams of granular elastic material 12 are mixed and placed into a pretreatment vessel. Then, the pretreatment vessel is sealed, and thus the pretreatment vessel is in an airtight state. Then, the pretreatment vessel is placed in a constant temperature water tank and maintained at 60° C. or higher. Then, a vacuum pump is turned on for at least one hour in order to create a vacuum environment within the pretreatment vessel. Then, the thermally-conductive material 13 and the granular elastic material 12 are removed from the pretreatment vessel and poured into a stirring device. Then, 3000 grams of hydrogen storage material 11 is poured into the stirring device. The stirring device is operated for at least 5 minutes to uniformly mix these components. Meanwhile, the process of forming and pretreating the hydrogen storage composition 1 is completed. Meanwhile, the formulation A is produced.

(21) The processes of producing the formulations B, C and D are similar to the process of producing the formulation A except for the weight of the thermally-conductive material 13. The processes of pretreating the hydrogen storage compositions 1 containing the formulations B, C and D are similar to the process of pretreating the hydrogen storage composition containing the formulation A.

(22) Production of Hydrogen Storage Container and Hydrogen Activation

(23) The canister body 30 of the hydrogen storage container 3 is a cylindrical canister body with the following dimensions. For example, the length is 297 mm, the diameter is 76.2 mm, and the wall thickness 2.0 mm. Moreover, the designed pressure is 3.2 MPa.

(24) Firstly, a canister body 30 is provided. The canister body 30 is sealed and contains at least one gas conducting element (e.g., a through-hole or a gas-penetrative pipe). Then, the formulation A after pretreatment is placed into the canister body 30. Then, the airtight canister body 30 is placed in a constant temperature water tank and maintained at 60° C. or higher. Then, a vacuum pump is turned on to create a vacuum environment within the canister body 30, and the weight of the canister body 30 is recorded. The weight of the canister body 30 indicates the weight of the canister body 30 before the canister body 30 is charged with hydrogen gas. Then, the canister body 30 is placed in a hydrogen supply system with cold water circulation (5˜20° C.) and pure hydrogen gas is charged into the canister body 30 at a pressure of 1 MPa for at least one hour. Consequently, hydrogen gas is charged into the canister body 30 to activate the hydrogen storage material 11. The weight of the canister body 30 is recorded. The weight of the canister body 30 indicates the weight of the canister body 30 after the canister body 30 is charged with hydrogen gas. Then, a hydrogen storage amount is calculated according to the result of comparing the weight of the canister body 30 before charged with hydrogen gas and the weight of the canister body 30 after charged with hydrogen gas. If the hydrogen storage amount reaches the predetermined value, the hydrogen storage container 3 is produced. If the hydrogen storage amount does not reach the predetermined value, the above processes are repeatedly done until the hydrogen storage amount reaches the predetermined value.

(25) The components of the formulations B, C and D are similar to the components of the formulation A except for the weight of the thermally-conductive material 13 (e.g., aluminum fiber). The processes of producing the hydrogen storage container 3 containing the formulations B, C and D are similar to the process of producing the hydrogen storage container 3 containing the formulation A, and are not redundantly described herein.

(26) Results of Experiment

(27) As mentioned above, the four formulations A, B, C and D are prepared by mixing different amounts of thermally-conductive material 13 (e.g., aluminum fiber), a fixed amount of granular elastic material 12 (e.g., PU granule) and a fixed amount of hydrogen storage material 11. The hydrogen storage amounts of the hydrogen storage containers containing different formulations are listed in Table 1.

(28) TABLE-US-00001 TABLE 1 Weight(g) Weight(g) hydrogen before charged with after charged with storage amount Formulation hydrogen hydrogen (g) A 3791.68 3839.78 45.37 B 3840.39 3888.51 45.39 C 3873.72 3922.92 46.41 D 3952.87 4002.06 46.35

(29) Please refer to Table 1. As the fraction of the thermally-conductive material 13 increases, the hydrogen storage amount gradually increases. Moreover, in each formulation, the weight percentage of the hydrogen storage amount of the hydrogen storage material 11 (i.e., the hydrogen storage amount of the hydrogen storage container 3) with respect to the weight of the hydrogen storage material 11 is about 1.5%.

(30) FIG. 4 schematically illustrates some positions of measuring the deformation of the hydrogen storage container according to an embodiment of the present invention. For example, the deformation values at the positions a, b, c, d, e and f of the canister body 30 are measured. The measuring results are listed in Table 2.

(31) TABLE-US-00002 TABLE 2 Formula Before/after A B C D charged with hydrogen Before After Before After Before After Before After Deformation a 76.35 76.38 76.1 76.1 76.2 76.2 76.1 76 measured b 76.1 76.38 76 76 75.9 75.8 76.1 75.95 at c 76.32 76.28 76.05 76 75.95 75.9 76.15 76 different d 76.3 76.28 76.2 76.25 76.25 76.25 75.85 76 positions e 76.32 76.42 76.3 76.3 76.25 76.25 75.8 76.05 (mm) f 76.18 76.24 76.25 76.25 76.1 76.15 75.8 76.05

(32) Please refer to Table 2 again. In the hydrogen storage container 3 containing the formulation A, B, C or D, the deformation values measured at different positions before charged with hydrogen gas and after charged with hydrogen gas are very small. In other words, the addition of the granular elastic material 12 can alleviate the deformation (or strain) that is resulted from the volume expansion or shrinkage of the hydrogen storage material 11. Furthermore, there is no obvious displacement of the hydrogen storage material 11 with respect to the granular elastic material 13 and thermally-conductive material 13. Since the deformation of the canister body 30 is reduced and the displacements of the hydrogen storage composition 1 is avoided, the durability and safety of the canister body 30 are enhanced.

(33) FIG. 5 is a plot illustrating the hydrogen desorption curves of the hydrogen storage compositions 1 containing the formulations A, B, C and D. The experiments of acquiring the hydrogen desorption curves are carried out in water (50° C.). Initially, hydrogen gas is discharged from the hydrogen storage container 3 at the hydrogen desorption rate of 8 liter/min. Until the hydrogen desorption rate is 0.5 liter/min, the discharge of hydrogen gas is stopped. The hydrogen desorption curves of the hydrogen storage compositions 1 containing the formulations A, B, C and D are shown in FIG. 5. The hydrogen storage composition 1 containing the formulation A can discharge hydrogen gas at the hydrogen desorption rate of 8 liter/min for 1300 seconds. The hydrogen storage composition 1 containing the formulation B can discharge hydrogen gas at the hydrogen desorption rate of 8 liter/min for 2200 seconds. The hydrogen storage composition 1 containing the formulation C can discharge hydrogen gas at the hydrogen desorption rate of 8 liter/min for 2900 seconds. The hydrogen storage composition 1 containing the formulation D can discharge hydrogen gas at the hydrogen desorption rate of 8 liter/min for 3200 seconds. The results of the experiments demonstrate that the hydrogen desorption duration increases with the increasing amount of the thermally-conductive material 13. Since the thermally-conductive material 13 has the strip-like structure, the thermal conduction efficacy of the hydrogen storage composition 1 is enhanced. Under this circumstance, the efficiency of discharging hydrogen gas, the discharged amount of hydrogen gas and the hydrogen desorption duration increase. Since the thermally-conductive material 13, the hydrogen storage material 11 and the elastic material 12 of the hydrogen storage composition 1 are directly mixed with each other, the hydrogen storage composition 1 possesses the function of the aluminum boxes of the conventional technology. According to the present invention, the necking procedure is previously performed because it is not necessary to place the aluminum boxes into the canister body 30. When compared with the conventional technology, the process of pouring the hydrogen storage material into plural aluminum boxes, the process of placing the aluminum boxes into the canister body and the two thermally-treating processes are not required. Consequently, the method of producing the hydrogen storage container 3 according to the present invention is time-saving and labor-saving.

(34) From the above descriptions, the thermally-conductive material and the granular elastic material of the hydrogen storage composition are used for replacing the aluminum boxes of the conventional technology. The use of the granular elastic material can alleviate a deformation resulted from a volume expansion or shrinkage of the hydrogen storage material. The use of the thermally-conductive material can increase the thermal conduction efficacy of the hydrogen storage composition and alleviate a displacement of granular elastic material relative to the hydrogen storage material. Consequently, it facilitates the hydrogen storage composition to achieve an optimized packing density and the discharged amount of hydrogen gas and the hydrogen desorption duration increase. Moreover, the addition of the granular elastic material can alleviate the deformation (or strain) that is resulted from the volume expansion or shrinkage of the hydrogen storage material and limited by the thermally-conductive material. Since the deformation of the canister body is reduced, the durability and safety of the canister body are enhanced. Since the hydrogen storage composition is a mixture of pure separable states, and the hydrogen storage material, the granular elastic material and the thermally-conductive material are separable by physical classification, it facilitates the hydrogen storage composition to be adjustable and reworked according to the practical requirements. Furthermore, the process of pouring the hydrogen storage material into plural aluminum boxes, the process of placing the aluminum boxes into the canister body and the two thermally-treating processes are not needed, the method of producing the hydrogen storage container according to the present invention is cost-effective, material-saving, labor-saving and time-saving. In other words, the hydrogen storage composition and the method for producing the hydrogen storage container according to the present invention are industrially valuable.

(35) While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.