阅读说明：本技术 含碳复合储氢合金及其制备方法、复合固态储氢罐及储放氢性能测试方法 (Carbon-containing composite hydrogen storage alloy and preparation method thereof, composite solid hydrogen storage tank and hydrogen storage performance testing method ) 是由 武英 原建光 张宝 阎有花 周少雄 于 2019-11-07 设计创作，主要内容包括：本发明公开了一种含碳复合储氢合金及其制备方法、利用所述含碳复合储氢合金制成的复合固态储氢罐,以及对该复合固态储氢罐进行储氢性能测试的方法。一种含碳复合储氢合金,按质量百分比计,所述含碳复合储氢合金由90％-98％的储氢合金粉末和2％-10％的碳材料制成。一种制备上述含碳复合储氢合金的方法,包括以下步骤：制备储氢合金粉末的步骤；准备所述碳材料的步骤；将所述碳材料与所述储氢合金粉末混合制成所述含碳复合储氢合金的步骤。本发明制备的复合固态储氢罐可以用于氢气纯化、燃料电池氢源及固定式储能等领域。(The invention discloses a carbon-containing composite hydrogen storage alloy and a preparation method thereof, a composite solid hydrogen storage tank made of the carbon-containing composite hydrogen storage alloy, and a method for testing the hydrogen storage performance of the composite solid hydrogen storage tank. A carbon-containing composite hydrogen storage alloy is prepared from 90-98% of hydrogen storage alloy powder and 2-10% of carbon material by mass percentage. A method for preparing the carbon-containing composite hydrogen storage alloy comprises the following steps: a step of preparing hydrogen storage alloy powder; preparing the carbon material; and a step of mixing the carbon material with the hydrogen storage alloy powder to produce the carbon-containing composite hydrogen storage alloy. The composite solid hydrogen storage tank prepared by the invention can be used in the fields of hydrogen purification, fuel cell hydrogen sources, fixed energy storage and the like.)

1. A carbon-containing composite hydrogen storage alloy is characterized in that the carbon-containing composite hydrogen storage alloy is prepared from 90-98% of hydrogen storage alloy powder and 2-10% of carbon material by mass percentage.

2. The carbon-containing composite hydrogen occluding alloy according to claim 1,

the carbon material comprises one or more of graphite, activated carbon, carbon black, carbon fiber, carbon aerogel, carbon nanotubes and graphene;

preferably, when the carbon material is a graphite material, the particle size of the carbon material is 1mm or less, preferably 100-; more preferably, the graphite material is one or more of high purity graphite, expanded graphite and flake graphite nodules;

when the carbon material is activated carbon, the particle size of the activated carbon is mainly in the order of μm; more preferably 80% or more of the size is in the order of μm; more preferably, the activated carbon is one or more of black powdered, blocky, granular and honeycomb activated carbon; more preferably, the particle size of the activated carbon is 100-500 μm.

When the carbon material is carbon black, the particle size of the carbon black is in the order of μm, preferably 100-500 μm;

when the carbon material is carbon aerogel, the porosity of the carbon material is 80-99.8%, and the typical pore size range is 1-100 nm;

when the carbon material is carbon fiber, the carbon fiber is a microcrystalline graphite material which is formed by stacking flake graphite microcrystalline organic fibers along the axial direction of the fiber and is obtained through carbonization and graphitization treatment, the carbon fiber is short carbon fiber, the fiber length of the carbon fiber is 1-100 mm, and the fiber diameter is 1-10 mu m;

when the carbon material is a carbon nanotube, the inner diameter of the carbon nanotube is 10-50 nm, and the length of the carbon nanotube is 100 nm-1 μm;

when the carbon material is graphene, the graphene is a graphene nanosheet, the graphene nanosheet has a transverse dimension of 5-20 μm and a thickness of less than 20 nm.

3. The carbon-containing composite hydrogen occluding alloy according to claim 1 or 2,

the hydrogen storage alloy powder comprises rare earth AB₅Type, titanium AB type₂One or more of type and titanium vanadium solid solution type hydrogen storage alloy powder;

preferably, the average particle size of the hydrogen storage alloy powder is 75-300 μm;

preferably, the rare earth system AB₅In the hydrogen occluding alloy powder of type A, the A-side metal is composed of La and at least 1 of the elements of the group of Ce, Pr, Nd, Sm, Gd, Dy, Mg, Ti and Zr, and the B-side metal is composed of Ni and at least 1 of the elements of the group of Co, Mn, Cu, Fe, Si, Ge, Sn, Cr, Zn, B, V, W, Mo, Ta and Nb.

4. A method for producing the carbon-containing composite hydrogen occluding alloy as recited in any one of claims 1 to 3, comprising the steps of:

a step of preparing hydrogen storage alloy powder;

preparing the carbon material;

and a step of mixing the carbon material with the hydrogen storage alloy powder to produce the carbon-containing composite hydrogen storage alloy.

5. The method of claim 4,

the step of preparing the hydrogen storage alloy powder includes:

smelting the raw materials of the hydrogen storage alloy powder to prepare a hydrogen storage alloy ingot, and then carrying out vacuum annealing homogenization treatment on the alloy ingot, wherein the smelting temperature is 1300-1500 ℃, the vacuum annealing homogenization treatment temperature is 800-1150 ℃, and the annealing time is 5-10 h; and then crushing and ball-milling the annealed hydrogen storage alloy ingot to obtain the hydrogen storage alloy powder.

6. The method of claim 4,

in the step of mixing the carbon material with the hydrogen storage alloy powder to produce the carbon-containing composite hydrogen storage alloy,

and stirring and mixing the prepared hydrogen storage alloy powder and a carbon material for 1-5 hours to prepare the carbon-containing composite hydrogen storage alloy.

7. A composite solid hydrogen storage tank comprising a tank body and the carbon-containing composite hydrogen storage alloy according to any one of claims 1 to 3 provided in the tank body;

preferably, the material of the tank body is metal aluminum or aluminum alloy, and is more preferably 616 aluminum alloy; further preferably, the can body includes a straight tube portion and an opening portion extending from the straight tube portion and narrowing;

more preferably, the composite solid-state hydrogen storage tank further comprises a filter and a valve, wherein the filter is embedded in the opening portion of the tank body, and the valve is mounted on the opening portion and used for closing or opening the opening portion of the tank body;

preferably, the inner diameter of the tank body of the hydrogen storage tank is 70-80mm, the outer diameter is 80-90mm, the length of the straight cylinder part is 275-285mm, and the volume is 1-1.5L; more preferably, the outer diameter of the body of the hydrogen storage tank is 85mm, the inner diameter is 85mm, the length of the straight cylinder part is 280mm, and the volume is 1L.

8. The method for testing the hydrogen storage performance of a composite solid hydrogen storage tank of claim 7, comprising the steps of:

installing the composite solid hydrogen storage tank into a hydrogen storage tank hydrogen charging and activating treatment device, and sequentially performing activation, hydrogen charging and hydrogen discharging performance tests on the carbon-containing composite hydrogen storage alloy in the composite solid hydrogen storage tank;

preferably, the activating and charging comprises: controlling the temperature of the composite solid hydrogen storage tank within the range of 80-120 ℃, and simultaneously carrying out vacuum pumping treatment on the composite solid hydrogen storage tank for 5-10 h; filling hydrogen into the composite solid hydrogen storage tank, wherein the pressure of the hydrogen in the composite solid hydrogen storage tank is 2-10MPa, and the pressure holding time is 5-10 h;

preferably, the hydrogen discharge performance test comprises: controlling the hydrogen release temperature to be 5-50 ℃, controlling the hydrogen release flow rate to be 2-8L/min, monitoring the pressure value in the hydrogen storage tank in real time, and stopping hydrogen release time recording when the hydrogen release flow rate is reduced to a preset flow rate to obtain the hydrogen release time and the hydrogen release amount of the hydrogen storage tank at a specific speed;

obtaining the hydrogen release amount percentage of the hydrogen storage tank in a specific time according to the obtained ratio of the hydrogen release amount to the total hydrogen storage amount of the hydrogen storage tank;

preferably, the hydrogen discharge flow rate is controlled to be 8L/min at 50 ℃, and when the hydrogen discharge flow rate is reduced to 6L/min, the hydrogen discharge time recording is stopped.

9. The test method according to claim 8,

the hydrogen storage tank hydrogen filling and activating treatment device comprises: a vacuum pump, a gaseous hydrogen cylinder and a water bath;

the vacuum pump is connected with the composite solid-state hydrogen storage tank through a vacuum pumping pipeline and is used for vacuumizing the composite solid-state hydrogen storage tank, and preferably, a vacuum pumping switch valve is arranged on the vacuum pumping pipeline;

the gaseous hydrogen cylinder is connected with the composite solid hydrogen storage tank through a hydrogen charging pipeline and used for supplying hydrogen to the hydrogen storage tank, and preferably, a pressure reducing valve, a mass flow controller and a hydrogen charging switch valve are sequentially arranged on the hydrogen charging pipeline along the hydrogen flow direction;

the water bath is arranged outside the composite solid hydrogen storage tank and used for heating the composite solid hydrogen storage tank.

10. The test method according to claim 9, wherein the hydrogen storage tank hydrogen charging and activation processing device further comprises:

the pressure sensor is arranged on a hydrogen discharge pipeline, one end of the hydrogen discharge pipeline is connected with the composite solid hydrogen storage tank, and the pressure sensor is used for monitoring the real-time pressure of the composite solid hydrogen storage tank during hydrogen discharge; preferably, an electromagnetic valve, a mass flow controller, a back pressure valve, a hydrogen discharge switch valve and a one-way valve are sequentially arranged on the hydrogen discharge pipeline along the gas flowing direction.

Technical Field

The invention belongs to the technical field of hydrogen storage material preparation, and particularly relates to a carbon-containing composite hydrogen storage alloy prepared by matching a carbon material with a hydrogen storage alloy, a preparation method of the carbon-containing composite hydrogen storage alloy, a composite solid hydrogen storage tank prepared by using the carbon-containing composite hydrogen storage alloy, and a method for testing the hydrogen storage performance of the composite solid hydrogen storage tank.

Background

Exhaustion of fossil energy and environmental pollution crisis force human to develop renewable clean energy. Hydrogen is a clean secondary energy source, and is an ideal carrier of renewable primary energy sources. In the 70 s of the 20 th century, the U.S. general automobile company proposed the concept of "hydrogen economy era" to describe the future use of hydrogen instead of petroleum and natural gas as the main energy economy supporting global economy. Therefore, the development and utilization of hydrogen energy has become a scientific field of particular interest to countries throughout the world. In the research and development aspect of hydrogen energy, three major problems of hydrogen generation, storage and utilization are faced at present. The storage of hydrogen is the key to the development and utilization of hydrogen energy, and the research of hydrogen storage technology is regarded as an important technical project in many developed countries at present. The storage and transportation of hydrogen can be divided into 3 types according to the storage method of hydrogen: the first is a gas hydrogen storage technology, which stores hydrogen gas in a high-pressure container after compression, and has the disadvantages of small volume and small hydrogen storage amount of a steel cylinder for storing hydrogen gas and explosion risk; the second is a liquid hydrogen storage technology, i.e. the liquefied hydrogen is stored in a heat-insulating container, the liquid hydrogen storage is generally applied to major projects such as aerospace, and the hydrogen can be liquefied only by cooling to about-253 ℃, so that the energy consumption is high, the liquid storage tank is large, a good heat-insulating device is needed for heat insulation, the leakage is easy, the requirement on the heat-insulating property of the storage tank is high, and the problems restrict the wide application of the hydrogen energy; the third is solid hydrogen storage technology, namely a solid hydrogen storage mode that hydrogen and hydrogen storage materials are combined in a physical or chemical mode, can effectively overcome the defects of a gas storage mode and a liquid storage mode, and has the advantages of large hydrogen storage volume density, high safety degree, convenient transportation and easy operation. With the application of the hydrogen storage alloy, hydrogen can be stored in the hydrogen storage alloy in the form of atoms or hydrides, and the hydrogen storage alloy has the advantages of high hydrogen storage density, relatively low requirements on high pressure resistance and heat insulation performance of a storage container, good safety and the like, and becomes a potential ideal mode for storing hydrogen.

In recent years, various researchers in various countries have made a lot of research works on solid-state hydrogen storage technology, so that solid-state hydrogen storage alloys have been rapidly developed and put into commercial use. The hydrogen storage tank using the hydrogen storage alloy as the storage medium has high storage density, can conveniently provide hydrogen sources for fuel cells used in various occasions, and is particularly suitable for providing safe and reliable hydrogen sources for mobile tools driven by various fuel cells, such as electric automobiles, electric motorcycles and electric bicycles.

However, the hydrogen storage alloy absorbs hydrogen and expands with about 25% volume, and the volume shrinks after hydrogen release, so after a plurality of hydrogen absorption and release cycles, the hydrogen storage alloy can be gradually pulverized, and meanwhile, the hydrogen storage alloy powder is easy to flow along with the flow of hydrogen in the hydrogen absorption and release process, so that the hydrogen storage alloy powder is accumulated, a hydrogen storage device loses gaps locally, and a hydrogen storage tank deforms, even cracks and damages in the hydrogen absorption and release process of the hydrogen storage alloy, thereby causing safety accidents. The hydrogen storage alloy powder has serious heat effect, and the heat of hydrogen absorption reaction can be timely transmitted out and the heat of hydrogen desorption reaction can be timely provided.

Therefore, it is highly desired to develop a composite hydrogen storage tank made of a hydrogen storage material which can effectively prevent the pulverization of the hydrogen storage alloy, improve the heat exchange performance, and release hydrogen at a stable flow rate.

Disclosure of Invention

The invention provides a carbon-containing composite hydrogen storage alloy and a preparation method thereof.

The invention also provides a composite solid hydrogen storage tank made of the carbon-containing composite hydrogen storage alloy and a method for testing the hydrogen storage performance of the composite solid hydrogen storage tank.

The technical scheme of the invention is as follows:

a carbon-containing composite hydrogen storage alloy is prepared from 90-98% of hydrogen storage alloy powder and 2-10% of carbon material by mass percentage.

In the above carbon-containing composite hydrogen storage alloy, as a preferred embodiment, the carbon material includes one or more of graphite, activated carbon, carbon black, carbon fiber, carbon aerogel, carbon nanotube, and graphene; preferably, when the carbon material is a graphite material, the particle size of the carbon material is 1mm or less, preferably 100-; more preferably, the graphite material is one or more of high purity graphite, expanded graphite and flake graphite nodules; when the carbon material is activated carbon, the particle size of the activated carbon is mainly in the order of μm; more preferably 80% or more of the size is in the order of μm; more preferably, the activated carbon is one or more of black powdered, blocky, granular and honeycomb activated carbon; more preferably, the particle size of the activated carbon is 100-500 μm. When the carbon material is carbon black, the particle size of the carbon black is in the order of μm, preferably 100-500 μm; when the carbon material is carbon aerogel, the porosity of the carbon material is 80-99.8%, and the typical pore size range is 1-100 nm; when the carbon material is carbon fiber, the carbon fiber is a microcrystalline graphite material which is formed by stacking flake graphite microcrystalline organic fibers along the axial direction of the fiber and is obtained through carbonization and graphitization treatment, the carbon fiber is short carbon fiber, the fiber length of the carbon fiber is 1-100 mm, and the fiber diameter is 1-10 mu m; when the carbon material is a carbon nanotube, the inner diameter of the carbon nanotube is 10-50 nm, and the length of the carbon nanotube is 100 nm-1 μm; when the carbon material is graphene, the graphene is a graphene nanosheet, the graphene nanosheet has a transverse dimension of 5-20 μm and a thickness of less than 20 nm.

In the above-mentioned carbon-containing composite hydrogen storage alloy, as a preferred embodiment, the hydrogen storage alloy powder includes a rare earth-based AB₅Type and titanium ABType and titanium AB₂One or more of type and titanium vanadium solid solution type hydrogen storage alloy powder; preferably, the average particle size of the hydrogen storage alloy powder is 75-300 μm; preferably, the rare earth system AB₅In the hydrogen occluding alloy powder of type A, the A-side metal is composed of La and at least 1 of the elements of the group of Ce, Pr, Nd, Sm, Gd, Dy, Mg, Ti and Zr, and the B-side metal is composed of Ni and at least 1 of the elements of the group of Co, Mn, Cu, Fe, Si, Ge, Sn, Cr, Zn, B, V, W, Mo, Ta and Nb.

The method for preparing the carbon-containing composite hydrogen storage alloy is characterized by comprising the following steps of: a step of preparing hydrogen storage alloy powder; preparing the carbon material; and a step of mixing the carbon material with the hydrogen storage alloy powder to produce the carbon-containing composite hydrogen storage alloy.

In the above method, as a preferred embodiment, the step of preparing the hydrogen occluding alloy powder includes: smelting the raw materials of the hydrogen storage alloy powder to prepare a hydrogen storage alloy ingot, and then carrying out vacuum annealing homogenization treatment on the alloy ingot, wherein the smelting temperature is 1300-1500 ℃, the vacuum annealing homogenization treatment temperature is 800-1150 ℃, and the annealing time is 5-10 h; and then crushing and ball-milling the annealed hydrogen storage alloy ingot to obtain the hydrogen storage alloy powder.

In the above method, as a preferred embodiment, in the step of mixing the carbon material with the hydrogen storage alloy powder to produce the carbon-containing composite hydrogen storage alloy, the produced hydrogen storage alloy powder and the carbon material are stirred and mixed for 1 to 5 hours to produce the carbon-containing composite hydrogen storage alloy.

A composite solid hydrogen storage tank comprises a tank body and the carbon-containing composite hydrogen storage alloy arranged in the tank body; preferably, the material of the tank body is metal aluminum or aluminum alloy, and is more preferably 616 aluminum alloy; further preferably, the can body includes a straight tube portion and an opening portion extending from the straight tube portion and narrowing; more preferably, the composite solid-state hydrogen storage tank further comprises a filter and a valve, wherein the filter is embedded in the opening portion of the tank body, and the valve is mounted on the opening portion and used for closing or opening the opening portion of the tank body; preferably, the inner diameter of the tank body of the hydrogen storage tank is 70-80mm, the outer diameter is 80-90mm, the length of the straight cylinder part is 275-285mm, and the volume is 1-1.5L; more preferably, the outer diameter of the body of the hydrogen storage tank is 85mm, the inner diameter is 85mm, the length of the straight cylinder part is 280mm, and the volume is 1L.

A method for testing the hydrogen storage performance of a composite solid hydrogen storage and discharge tank comprises the following steps: installing the composite solid hydrogen storage tank into a hydrogen storage tank hydrogen charging and activating treatment device, and sequentially performing activation, hydrogen charging and hydrogen discharging performance tests on the carbon-containing composite hydrogen storage alloy in the composite solid hydrogen storage tank; preferably, the activating and charging comprises: controlling the temperature of the composite solid hydrogen storage tank within the range of 80-120 ℃, and simultaneously carrying out vacuum pumping treatment on the composite solid hydrogen storage tank for 5-10 h; filling hydrogen into the composite solid hydrogen storage tank, wherein the pressure of the hydrogen in the composite solid hydrogen storage tank is 2-10MPa, and the pressure holding time is 5-10 h; preferably, the hydrogen discharge performance test comprises: controlling the hydrogen release temperature to be 5-50 ℃, controlling the hydrogen release flow rate to be 2-8L/min, monitoring the pressure value in the hydrogen storage tank in real time, and stopping hydrogen release time recording when the hydrogen release flow rate is reduced to a preset flow rate to obtain the hydrogen release time and the hydrogen release amount of the hydrogen storage tank at a specific speed; obtaining the hydrogen release amount percentage of the hydrogen storage tank in a specific time according to the obtained ratio of the hydrogen release amount to the total hydrogen storage amount of the hydrogen storage tank; preferably, the hydrogen discharge flow rate is controlled to be 8L/min at 50 ℃, and when the hydrogen discharge flow rate is reduced to 6L/min, the hydrogen discharge time recording is stopped.

In the above test method, as a preferred embodiment, the hydrogen tank charging and activating treatment apparatus includes: a vacuum pump, a gaseous hydrogen cylinder and a water bath; the vacuum pump is connected with the composite solid-state hydrogen storage tank through a vacuum pumping pipeline and is used for vacuumizing the composite solid-state hydrogen storage tank, and preferably, a vacuum pumping switch valve is arranged on the vacuum pumping pipeline; the gaseous hydrogen cylinder is connected with the composite solid hydrogen storage tank through a hydrogen charging pipeline and used for supplying hydrogen to the hydrogen storage tank, and preferably, a pressure reducing valve, a mass flow controller and a hydrogen charging switch valve are sequentially arranged on the hydrogen charging pipeline along the hydrogen flow direction; the water bath is arranged outside the composite solid hydrogen storage tank and used for heating the composite solid hydrogen storage tank.

In the above test method, as a preferred embodiment, the hydrogen tank charging and activating treatment apparatus further includes: the pressure sensor is arranged on a hydrogen discharge pipeline, one end of the hydrogen discharge pipeline is connected with the composite solid hydrogen storage tank, and the pressure sensor is used for monitoring the real-time pressure of the composite solid hydrogen storage tank during hydrogen discharge; preferably, an electromagnetic valve, a mass flow controller, a back pressure valve, a hydrogen discharge switch valve and a one-way valve are sequentially arranged on the hydrogen discharge pipeline along the gas flowing direction.

The invention discloses the technical effects that:

(1) the carbon material is low in price, has good thermal conductivity and thermal stability, reduces grain boundary migration and grain growth of the hydrogen storage alloy due to hydrogen absorption and desorption thermal effects, and can be used as a good catalyst carrier in the hydrogen storage alloy. Meanwhile, the composite material has the characteristics of developed internal pore structure, low bulk density, strong adsorption capacity, low density, high specific surface area, high heat conductivity and the like, and can play the roles of a grinding aid and a surfactant. And the carbon-based material has certain hydrogen storage performance, and the carbon-based material is compounded with the hydrogen storage alloy, so that the hydrogen storage performance of the hydrogen storage alloy can be effectively improved in an auxiliary manner.

(2) The hydrogen storage tank has the characteristics of good safety, high hydrogen storage density, pulverization resistance, high heat conduction rate, excellent hydrogen absorption and desorption rate and the like, and solves the technical problems of poor hydrogen storage safety, high energy consumption, low hydrogen storage density and the like in the prior art.

(3) The composite solid hydrogen storage tank prepared by the invention can be used in the fields of hydrogen purification, fuel cell hydrogen sources, fixed energy storage and the like.

(4) The composite solid hydrogen storage tank provided by the invention discharges hydrogen at the hydrogen discharge flow rate of 8L/Min at 50 ℃, the hydrogen discharge time can reach 58Min, the hydrogen discharge amount can reach 464L, and the hydrogen discharge amount can reach 92.8% of the hydrogen storage amount of the hydrogen storage tank.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. Wherein:

FIG. 1 is a cross-sectional view of a composite solid hydrogen storage canister provided by the present invention;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a schematic system diagram of a hydrogen storage tank charging and activating device according to the present invention;

FIG. 4 is a graph showing the change of the hydrogen desorption flow rate and the hydrogen desorption pressure with time of the composite hydrogen storage alloy powder (example 1) containing 20 to 100nm of high purity graphite (carbon content of graphite > 99.99%) in an amount of 10 wt.% in a hydrogen storage tank;

FIG. 5 is a graph showing the change of the hydrogen desorption flow rate and the hydrogen desorption pressure with time, in the hydrogen storage tank, with the multiwall carbon nanotube composite hydrogen storage alloy powder (example 6) having a length of 1 μm and an inner diameter of a tube of 10 to 20nm, in an amount of 10 wt.%.

Reference numerals:

1. a gaseous hydrogen cylinder, 2, a vacuum pump;

3. a composite solid hydrogen storage tank 31, a tank body, 32 carbon-containing composite hydrogen storage alloy, 33, a filter and 34, a valve;

41. the device comprises a vacuumizing switch valve, 42, a hydrogen charging switch valve, 43, a hydrogen discharging switch valve, 5, a mass flow controller, 6, a pressure reducing valve, 7, a pressure sensor, 8, an electromagnetic valve, 9, a back pressure valve, 10, a one-way valve and 11, a water bath.

Detailed Description

The invention will be described in detail below with reference to specific embodiments with reference to the attached drawings. The various examples are provided by way of explanation of the invention, and not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. It is therefore intended that the present invention encompass such modifications and variations as fall within the scope of the appended claims and equivalents thereof.

A carbon-containing composite hydrogen storage alloy is made of, by mass, 90% to 98% of hydrogen storage alloy powder and 2% to 10% (e.g., 3%, 4%, 5%, 6%, 7%, 8%, 9%) of a carbon material. The carbon-containing composite hydrogen storage alloy is preferably used in a hydrogen storage tank having a volume of 1L. More preferably, the mass percentage of the carbon material is 8 to 10%.

The carbon material is low in price, has good thermal conductivity and thermal stability, reduces grain boundary migration and grain growth of the hydrogen storage alloy due to hydrogen absorption and desorption thermal effects, and can be used as a good catalyst carrier in the hydrogen storage alloy. Meanwhile, the composite material has the characteristics of developed internal pore structure, low bulk density, strong adsorption capacity, low density, high specific surface area, high heat conductivity and the like, and can play the roles of a grinding aid and a surfactant. And the carbon-based material has certain hydrogen storage performance, and the carbon-based material is compounded with the hydrogen storage alloy, so that the hydrogen storage performance of the hydrogen storage alloy can be effectively improved in an auxiliary manner. Therefore, the carbon material is selected to be matched with the hydrogen storage alloy for use, so that the problem of heat conduction of the hydrogen storage material can be effectively solved, the hydrogen discharge flow rate of the hydrogen storage alloy is improved, and the pulverization degree of the hydrogen storage alloy can be reduced to a certain degree.

The carbon material selected by the invention comprises one or more of graphite, activated carbon, carbon black, carbon fiber, carbon aerogel, carbon nano tube and graphene.

The average particle size of the hydrogen storage alloy powder selected by the invention is 75-300 μm, preferably 80-90 μm or 100-200 μm, including rare earth 5 series AB₅Type, titanium AB type₂One or more of type and titanium vanadium solid solution type hydrogen storage alloy. Preferably AB thereof₅In the rare earth type hydrogen occluding alloy, the A side is composed of La and at least 1 of the elements of Ce, Pr, Nd, Sm, Gd, Dy, Mg, Ti and Zr, and the B side metal is composed of Ni and at least 1 of the elements of Co, Mn, Cu, Fe, Si, Ge, Sn, Cr, Zn, B, V, W, Mo, Ta and Nb.

The method for preparing the carbon-containing composite hydrogen storage alloy comprises the following steps:

the preparation method of the hydrogen storage alloy powder comprises the following steps: smelting raw materials to prepare a hydrogen storage alloy ingot, and then carrying out vacuum annealing homogenization treatment on the alloy ingot, wherein the smelting temperature is 1300-1500 ℃, the vacuum annealing homogenization treatment temperature is 800-1150 ℃, and the annealing time is 5-10 h; and then crushing and ball-milling the annealed hydrogen storage alloy ingot to obtain hydrogen storage alloy powder with the granularity of 75-300 mu m.

Preparing a carbon material;

when the carbon material is a graphite material, the graphite material can be one or more of high-purity graphite, expanded graphite and scale graphite nodules, and the particle size of the graphite material is micron-level size, preferably 100-500 microns, and more preferably 100-200 microns; when the carbon material is activated carbon, the activated carbon can be one or more of black powdery or blocky, granular and honeycomb activated carbon, and the particle size of the activated carbon is micron-level size, preferably 100-500 microns, and more preferably 100-200 microns; when the carbon material is carbon black, the particle size of the carbon black is micron-sized, preferably 100-500 μm, more preferably 100-200 μm; when the carbon material is carbon aerogel, the porosity is 80% -99.8%, and the typical pore size range is 1-100 nm; when the carbon material is carbon fiber, the carbon fiber is preferably a microcrystalline graphite material obtained by stacking organic fibers such as flaky graphite microcrystals along the axial direction of the fiber and performing carbonization and graphitization treatment, and the carbon fiber is preferably short carbon fiber, the fiber length of the short carbon fiber is 1-100 mm, and the fiber diameter is 1-10 μm; when the carbon material is a carbon nanotube, the inner diameter of the carbon nanotube can be 10-50 nm, and the length is 100 nm-1 μm; when the carbon material is graphene, the graphene is preferably graphene nanosheet, the thickness of the two-dimensional graphite nanomaterial is nanoscale, the transverse dimension of the nanosheet is 5-20 microns, and the thickness of the nanosheet is not more than 20 nm. The carbon materials with different sizes and the hydrogen storage alloy powder have larger difference of volume and apparent density after being mixed, thereby causing larger influence on the heat conduction performance of the material.

The carbon material is mixed with hydrogen storage alloy powder to prepare the carbon-containing composite hydrogen storage alloy used in the hydrogen storage tank.

As shown in fig. 1, which is a cross-sectional view of the composite solid hydrogen storage tank provided by the present invention, fig. 2 is a top view of the hydrogen storage tank, which comprises a tank body 31, a filter 33 (for preventing powder from entering a charging or discharging line), a valve 34, and a carbon-containing composite hydrogen storage alloy 32 according to the present invention,

the tank body 31 of the hydrogen storage tank is made of 616 aluminum alloy, is a cylindrical cavity, and is provided with an opening part at one end, wherein the caliber of the opening part is 1/3 of the width of the cylindrical cavity; the filter 33 is embedded in the opening part of the can body, and the valve 34 is arranged on the opening part and is used for closing or opening the opening of the can body 31; the carbon-containing composite hydrogen storage alloy is filled in the cavity of the hydrogen storage tank. The inner diameter of the body 31 of the hydrogen storage tank can be set to 70-80mm, the outer diameter of the body 31 of the hydrogen storage tank is set to 80-90mm, the length of the straight cylinder is set to 275-285mm, and the volume is 1-1.5L.

The method for testing the hydrogen storage performance of the composite solid-state hydrogen storage tank comprises the following steps:

installing the composite solid hydrogen storage tank into a hydrogen storage tank hydrogen charging and activating treatment device, and sequentially performing activation, hydrogen charging and hydrogen discharging performance tests on the carbon-containing composite hydrogen storage alloy in the composite solid hydrogen storage tank;

in the above test method, preferably, the activating and charging comprises: controlling the temperature of the composite solid hydrogen storage tank within the range of 80-120 ℃, and simultaneously carrying out vacuum pumping treatment on the composite solid hydrogen storage tank for 5-10 h; filling hydrogen into the composite solid hydrogen storage tank, wherein the pressure of the hydrogen in the composite solid hydrogen storage tank is 2-10MPa, and the pressure holding time is 5-10 h;

in the above test method, preferably, the hydrogen discharge performance test includes: controlling the hydrogen release temperature to be 5-50 ℃, controlling the hydrogen release flow rate to be 2-8L/min, monitoring the pressure value in the hydrogen storage tank in real time, stopping hydrogen release time recording when the hydrogen release flow rate is reduced to a preset flow rate (for example, the hydrogen release flow rate is 8L/min, and then the preset flow rate is 6L/min), and obtaining the hydrogen release time and the hydrogen release amount of the hydrogen storage tank in the time, wherein the hydrogen release time can be the hydrogen release time at the hydrogen release flow rate of 8L/min;

obtaining the hydrogen release amount percentage of the hydrogen storage tank in a specific time according to the obtained ratio of the hydrogen release amount to the total hydrogen storage amount of the hydrogen storage tank;

preferably, the hydrogen discharge flow rate is controlled to be 8L/min at 50 ℃, and when the hydrogen discharge flow rate is reduced to 6L/min, the hydrogen discharge time recording is stopped.

The scheme of the invention, and the method and the result of the hydrogen storage performance detection by using the hydrogen storage tank provided by the invention are specifically described by the following specific examples.

The hydrogen storage alloys selected in the following examples are all rare earth based AB₅A type alloy in which the A side is composed of La and at least 1 of the elements of Ce, Pr, Nd, Sm, Gd, Dy, Mg, Ti and Zr, and the B side metal is composed of Ni and at least 1 of the elements of Co, Mn, Cu, Fe, Si, Ge, Sn, Cr, Zn, B, V, W, Mo, Ta and Nb as raw materials. The hydrogen occluding alloy used in the following examples and comparative examples was La_0.9Ce_0.1Ni_4.7Co_0.1Mn_0.1Al_0.1(the subscripts of each element represent the molar ratio of each element).

In the following examples, in order to facilitate the test of the hydrogen storage performance of the hydrogen storage tanks, hydrogen storage tanks having an outer diameter of 85mm, an inner diameter of 85mm, a straight cylinder portion of 280mm in length and a capacity of 1L were used.

The hydrogen storage tank hydrogen filling and activating treatment device comprises: a vacuum pump, a gaseous hydrogen cylinder and a water bath;

the vacuum pump is connected with the composite solid-state hydrogen storage tank through a vacuum pumping pipeline and is used for vacuumizing the composite solid-state hydrogen storage tank, and preferably, a vacuum pumping switch valve is arranged on the vacuum pumping pipeline;

the gaseous hydrogen cylinder is connected with the composite solid hydrogen storage tank through a hydrogen charging pipeline and used for supplying hydrogen to the hydrogen storage tank, and preferably, a pressure reducing valve, a mass flow controller and a hydrogen charging switch valve are sequentially arranged on the hydrogen charging pipeline along the hydrogen flow direction;

the water bath is arranged outside the composite solid hydrogen storage tank and used for heating the composite solid hydrogen storage tank.

The pressure sensor is arranged on a hydrogen discharge pipeline, one end of the hydrogen discharge pipeline is connected with the composite solid hydrogen storage tank, and the pressure sensor is used for monitoring the real-time pressure of the composite solid hydrogen storage tank during hydrogen discharge; preferably, an electromagnetic valve, a mass flow controller, a back pressure valve, a hydrogen discharge switch valve and a one-way valve are sequentially arranged on the hydrogen discharge pipeline along the gas flowing direction. The mass flow controller needs to have a certain pressure difference when measuring the flow, so a back pressure valve and a one-way valve are added to ensure that the front side and the rear side of the mass flow controller are in the range of the test pressure difference.

The gaseous hydrogen cylinder, the vacuum pump and the pressure sensor are connected with the gas storage tank through a gas path interface;

preferably, the air passage interface is connected with the opening of the air storage tank through a metal braided hose and 1/4 quick connector.

The specific preparation method of the hydrogen occluding alloy powder used in the following examples was:

pretreatment of raw materials: polishing to remove surface oxides of the raw material rare earth metal, and drying moisture in the raw material metal such as nickel;

vacuum induction melting: adding Al into raw material metal according to the sequence of melting point and boiling point from bottom to top (bottom melting point and boiling point are highest)₂O₃Vacuumizing a crucible to 0.001-0.01 Pa, then baking and washing the crucible, filling inert gas to 0.04-0.05 MPa, adjusting power to start smelting, controlling the melt temperature to be 1300-1500 ℃, refining for 3-10 minutes after molten steel is completely melted, pouring into a water-cooled copper mold, and cooling for 40min and taking out;

and (3) heat treatment: and (3) carrying out heat treatment at the temperature of 800-1150 ℃ for 5-10h by using a high vacuum annealing furnace to finally obtain the hydrogen storage alloy block.

Preparing hydrogen storage alloy powder: and under the nitrogen protection atmosphere, carrying out high-energy crushing on the hydrogen storage alloy blocks to prepare powder by adopting 5MPa high-pressure gas nitrogen formed by compression of an air compressor, and grinding and screening by adopting a multi-layer rotary vibration screen after crushing to finally obtain hydrogen storage alloy powder with the granularity of 75-300 mu m.

The various starting materials used in the following examples and comparative examples are commercially available products.