Energy storage elements, their preparation methods and applications

Abstract

This invention discloses an energy storage element, its preparation method, and its applications. The energy storage element of this invention includes an elastic matrix; an energy storage material and a thermally conductive material are dispersed within the elastic matrix, and pores are distributed within the elastic matrix, the volume of which is 15-40% of the volume of the energy storage element. The energy storage element of this invention exhibits low strain, good shape retention, and minimal impact on the energy storage capacity of the energy storage material.

Description

Technical Field

[0001] This invention relates to an energy storage element, its preparation method, and its applications. Background Technology

[0002] Solid-state hydrogen storage involves a reversible reaction between a hydrogen storage alloy and hydrogen gas to form a metal hydride. This reaction releases a significant amount of heat during hydrogen absorption and absorbs a large amount of heat during hydrogen release. If the heat released during absorption cannot be dissipated in time, or the heat required for release cannot be replenished, the reaction will be limited or even stop. During hydrogen absorption and release, the hydrogen atoms moving in and out of the crystal lattice cause the hydrogen storage alloy to expand and contract, leading to alloy pulverization. Pulverized hydrogen storage alloys have reduced thermal conductivity, further affecting heat transfer between the alloy and the external environment. Moreover, pulverized hydrogen storage alloys are easily dispersed by the hydrogen flow, accumulating in the pipes and internal corners of the hydrogen storage equipment, clogging pipes, creating localized stress concentrations, damaging the container, and posing safety hazards.

[0003] CN114440123A discloses a hydrogen storage bed element for a solid-state hydrogen storage tank, comprising a hydrogen storage alloy, a gelling material, and a thermally conductive material. The gelling material is a two-component addition-type silica gel, which includes silica gel liquid A and silica gel liquid B. First, silica gel liquid A and the thermally conductive material are mixed evenly in a certain proportion to obtain a modified silica gel. Then, the energy storage alloy is mixed evenly with the modified silica gel. Next, silica gel liquid B is added and mixed evenly to solidify it into a granular mixture. Finally, the solidified granular mixture is pressed using a mold to obtain a block-shaped hydrogen storage bed element.

[0004] CN101636451B discloses a resin composition comprising a resin and a hydrogen storage alloy powder, wherein the deformation α generated on the wall of the hydrogen storage container is 1000 × 10⁻⁶ when hydrogen is absorbed and released in the container. -6 The hydrogen storage container is obtained by filling a container with a resin composition such that the volume ratio of the hydrogen storage alloy powder to the contents of the container is 40 to 80% by volume, wherein the resin is a gel-like resin with a consistency of 10 to 200 at 25°C.

[0005] Although the above methods can reduce the strain of the material, the hydrogen storage and release capacity of the material still needs to be improved. Summary of the Invention

[0006] In view of this, one object of the present invention is to provide an energy storage element that exhibits low strain, good shape retention, and minimal impact on the stored energy. Another object of the present invention is to provide a method for manufacturing the energy storage element. A further object of the present invention is to provide an application of the energy storage element.

[0007] On one hand, the present invention provides an energy storage element, including an elastic matrix; an energy storage material and a thermally conductive material are dispersed in the elastic matrix, and pores are distributed in the elastic matrix, the volume of which is 15-40% of the volume of the energy storage element.

[0008] According to the energy storage element of the present invention, preferably, the D of the energy storage material is... 50 The diameter of the thermally conductive material is 50–150 μm. 50 The size ranges from 30 to 150 μm.

[0009] According to the energy storage element of the present invention, preferably, the energy storage material is selected from one or more of rare earth hydrogen storage alloys, titanium hydrogen storage alloys, magnesium hydrogen storage alloys, vanadium-based solid solutions, coordination hydrides, metal nitrides, and carbon-based hydrogen storage materials.

[0010] The thermally conductive material is selected from one or more of metallic thermally conductive materials and carbon-based thermally conductive materials;

[0011] The elastic matrix is ​​formed of silicone rubber and / or silicone resin.

[0012] According to the energy storage element of the present invention, preferably, the elastic matrix is ​​1 to 50 parts by weight, the energy storage material is 1 to 500 parts by weight, and the thermally conductive material is 0.5 to 50 parts by weight.

[0013] According to the energy storage element of the present invention, preferably, under the same test conditions, the energy storage capacity of the energy storage element is M, the energy storage capacity of the energy storage material contained in the energy storage element is m, and M ≥ 0.8m.

[0014] On the other hand, the present invention provides a method for preparing an energy storage element, comprising the following steps: curing raw materials including an energy storage material, a material forming an elastic matrix, a thermally conductive material and a pore-forming agent.

[0015] According to the preparation method of the present invention, preferably, the material forming the elastic matrix includes an organosilicon polymer and a curing agent, and the pore-forming agent is selected from gaseous pore-forming agents or solid pore-forming agents that generate gas at the curing temperature.

[0016] According to the preparation method of the present invention, preferably, a first mixture containing an organosilicon polymer and an energy storage material is mixed with a second mixture containing a thermally conductive material, a solid pore-forming agent and a curing agent, and then vacuumed at 50-90°C for 15-50 minutes.

[0017] According to the preparation method of the present invention, preferably, a gaseous pore-forming agent is introduced into a mixture containing an organosilicon polymer, an energy storage material, a thermally conductive material and a curing agent, and then a vacuum is drawn at 50-90°C for 15-50 minutes.

[0018] In another aspect, the present invention provides the use of the above-described energy storage element or the energy storage element prepared by the above-described preparation method in storing hydrogen.

[0019] The energy storage element of this invention exhibits low strain, good shape retention, and minimal impact on the energy storage capacity of the energy storage material. It reduces the adverse effects of volume changes during hydrogen absorption and release by the hydrogen storage alloy, and minimizes the negative impact of alloy powdering on the energy storage device. Detailed Implementation

[0020] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0021] <Energy Storage Components>

[0022] The energy storage element of this invention includes an elastic matrix; an energy storage material and a thermally conductive material are dispersed within the elastic matrix; pores are distributed within the elastic matrix, and the volume of the pores is 15-40% of the volume of the energy storage element. This invention discovers that forming pores of appropriate volume within the elastic matrix can improve the energy storage and release capabilities of the energy storage element. If the pore volume is too small, the energy storage and release capabilities of the energy storage element cannot be sufficiently improved. If the pore volume is too large, the shape retention capability of the energy storage element will be reduced, and the energy storage material and thermally conductive material will easily overflow from the pores, affecting the performance of the energy storage element and causing adverse effects on the energy storage device.

[0023] In this invention, the volume of the pores is 15-40% of the volume of the energy storage element; preferably 20-35%; more preferably 25-30%. This enables the energy storage element to achieve higher energy storage and release, with smaller strain, and prevents the energy storage material and heat-conducting material from overflowing from the pores.

[0024] In this invention, the elastic matrix may be formed of silicone rubber and / or silicone resin. In some embodiments, the elastic matrix is ​​cured silicone rubber.

[0025] The elastic matrix can be 1 to 50 parts by weight; preferably 2 to 10 parts by weight; more preferably 5 to 8 parts by weight.

[0026] In this invention, the energy storage material can be a hydrogen storage alloy. For example, it can be one or more of rare earth-based hydrogen storage alloys, titanium-based hydrogen storage alloys, magnesium-based hydrogen storage alloys, vanadium-based solid solutions, coordination hydrides, metal nitrides, and carbon-based hydrogen storage materials.

[0027] In some embodiments, the hydrogen storage alloy is a rare-earth-based hydrogen storage alloy. The rare-earth-based hydrogen storage alloy can be an AB5 type hydrogen storage alloy. Preferably, the rare-earth-based hydrogen storage alloy is La. 1-x-y Ce x Ca yNi5; wherein 0≤x≤1, 0≤y≤0.5; preferably, 0.3≤x≤0.6, 0.05≤y≤0.2. According to one embodiment of the present invention, the hydrogen storage alloy is La. 0.5 Ce 0.4 Ca 0.1 Ni5.

[0028] In some embodiments, the hydrogen storage alloy is a titanium-manganese based hydrogen storage alloy. The titanium-manganese based hydrogen storage alloy can be an AB2 type hydrogen storage alloy. According to one embodiment of the present invention, the hydrogen storage alloy is TiMn2.

[0029] The hydrogen storage material can be 1 to 500 parts by weight; preferably 300 to 450 parts by weight; more preferably 350 to 400 parts by weight.

[0030] D of energy storage materials 50 The thickness can be 50–150 μm; preferably 80–120 μm; more preferably 90–110 μm. This allows the energy storage material to have sufficient contact with the energy to be stored, while also ensuring that the energy storage material is stably fixed in the elastic matrix.

[0031] The thermally conductive material of this invention can be selected from one or more of metallic thermally conductive materials and carbon-based thermally conductive materials. Examples of metallic thermally conductive materials include, but are not limited to, copper and aluminum. Examples of carbon-based thermally conductive materials include, but are not limited to, expanded graphite.

[0032] D of thermally conductive materials 50 The micrometer diameter is 30–150 μm; preferably 40–120 μm; more preferably 90–110 μm. This allows the thermal conductivity of the material to be fully utilized while reducing the probability of the material leaking out of the pores.

[0033] The thermally conductive material can be 0.5 to 50 parts by weight; preferably 1 to 20 parts by weight; more preferably 5 to 15 parts by weight.

[0034] Under the same test conditions, if the energy storage capacity of the energy storage element of the present invention is M, and the energy storage capacity of the energy storage material contained in the energy storage element is m, then M ≥ 0.8m; preferably, M ≥ 0.9m; more preferably, M ≥ 0.95m.

[0035] <Preparation Methods of Energy Storage Components>

[0036] The method for preparing the energy storage element of the present invention includes the following steps: curing raw materials comprising an energy storage material, a material forming an elastic matrix, a thermally conductive material, and a pore-forming agent. The above steps can be completed in a mold, and the resulting energy storage element is then processed and filled into an energy storage device. Alternatively, the above steps can be completed within the energy storage device, allowing the elastic matrix to be cured in situ.

[0037] The types of energy storage materials and D of the present invention50 As mentioned above, it will not be repeated here. The amount of energy storage material can be 1 to 500 parts by weight; preferably 300 to 450 parts by weight; more preferably 350 to 400 parts by weight.

[0038] The materials used to form the elastic matrix of the present invention may include silicone rubber and / or silicone resin. In some embodiments, the material forming the elastic matrix is ​​a two-component silicone rubber. The material forming the elastic matrix includes a silicone polymer and a curing agent. The mass ratio of the silicone polymer to the curing agent may be 1:(0.5-2); preferably 1:(0.8-1.5); more preferably 1:(1-1.2).

[0039] The amount of material forming the elastic matrix can be 1 to 50 parts by weight; preferably 2 to 10 parts by weight; more preferably 5 to 8 parts by weight.

[0040] The types of thermally conductive materials and D of the present invention 50 As mentioned above, it will not be repeated here. The amount of thermally conductive material can be 0.5 to 50 parts by weight; preferably 1 to 20 parts by weight; more preferably 5 to 15 parts by weight.

[0041] The pore-forming agent can be selected from gaseous pore-forming agents or solid pore-forming agents that generate gas at the curing temperature. Examples of gaseous pore-forming agents include, but are not limited to, carbon dioxide and argon. Examples of solid pore-forming agents include, but are not limited to, sodium bicarbonate and ammonium bicarbonate.

[0042] The amount of pore-forming agent can be determined based on the volume of pores formed in the energy storage element. In the energy storage element of the present invention, the volume of the pores is 15-40% of the volume of the energy storage element; preferably 20-35%; more preferably 25-30%.

[0043] In some embodiments, a first mixture containing an organosilicon polymer and an energy storage material is mixed with a second mixture containing a thermally conductive material, a solid pore-forming agent, and a curing agent, and then vacuumed at 50–90°C for 15–50 min. Preferably, after mixing the first and second mixtures, vacuuming is performed at 60–80°C for 20–40 min.

[0044] In some embodiments, a gaseous pore-forming agent is introduced into a mixture containing an organosilicon polymer, an energy storage material, a thermally conductive material, and a curing agent, followed by vacuuming at 50–90°C for 15–50 minutes. Preferably, after introducing the gaseous pore-forming agent, vacuuming is performed at 60–80°C for 20–40 minutes.

[0045] Applications of Energy Storage Components

[0046] The energy storage element of this invention has a high hydrogen storage capacity, low strain, and minimal impact on hydrogen storage equipment. Therefore, this invention provides the application of the above-mentioned energy storage element in hydrogen storage. The test method is described below:

[0047] The percentage of pore volume to the total volume of the energy storage element is calculated using the following formula:

[0048] (V2-V1) / V2×100%;

[0049] Where V2 is the volume of the energy storage element, and V1 is the volume of the first mixture and the second mixture after mixing.

[0050] Hydrogen storage capacity: The energy storage element with saturated hydrogen absorption was tested in a Sieverts PCT tester at a pressure of 5 MPa and a temperature of 40°C. The amount of hydrogen stored in the energy storage element during the reaction process was accumulated and integrated using a hydrogen mass flow controller to obtain the hydrogen storage capacity.

[0051] Morphology of the energy storage element after 30 cycles: The energy storage element was placed in a container with the appropriate pressure rating. A hydrogen cylinder with a pressure reducing valve was filled with sufficient hydrogen to saturate it with hydrogen absorption. Then, a vacuum pump was used to evacuate the container to completely remove the hydrogen, constituting one cycle. This process was repeated 30 times, and the morphology of the energy storage element was observed. The testing equipment was a Sieverts PCT tester, with a test pressure of 5 MPa and a test temperature of 40℃.

[0052] Strain: The energy storage element is placed in a container of the corresponding pressure rating, so that it is in complete contact with the container wall. The strain generated by the energy storage element on the container during the hydrogen absorption and desorption process is monitored by attaching strain gauges to the outer wall of the container.

[0053] The raw materials are described below:

[0054] The silicone polymer is the polymer component (component A) of the two-component silicone rubber with the brand name K-7054, and the curing agent is the curing component (component B) of the two-component silicone rubber with the brand name K-7054.

[0055] La 0.5 Ce 0.4 Ca 0.1 Ni5 energy storage material: It is formed by melting raw materials prepared according to the chemical formula in a medium-frequency vacuum induction melting furnace.

[0056] Examples 1-3 and Comparative Examples 1-3

[0057] D 50 A 100μm energy storage material and an organosilicon polymer are mixed evenly to form a first mixture. A thermally conductive material (if any), ammonium bicarbonate (if any), and a curing agent are mixed evenly to form a second mixture.

[0058] The first mixture and the second mixture are mixed evenly (the volume at this time is denoted as V1), and then vacuumed at 70°C for 30 minutes to obtain the energy storage element (the volume of the energy storage element is denoted as V2).

[0059] The specific parameters are shown in Table 1, and the performance of the obtained energy storage element is also shown in Table 1.

[0060] Comparative Example 4

[0061] The energy storage element in this comparative example has 400 parts by weight of La composition. 0.5 Ce 0.4 Ca 0.1 Ni5 AB5 type hydrogen storage alloy.

[0062] The performance of the energy storage components is shown in Table 1.

[0063] Table 1

[0064]

[0065] As demonstrated in Examples 1 and 3 and Comparative Example 1, the percentage of pore volume to the total volume of the energy storage element has a significant impact on its hydrogen storage capacity. When the pore volume accounts for 30% of the total volume, the energy storage element exhibits high energy storage capacity, comparable to that of the energy storage material (Comparative Example 4), and demonstrates good shape retention and low strain. Comparing Example 1 and Comparative Example 2, it is evident that the addition of an appropriate amount of thermally conductive material can improve the hydrogen storage capacity of the energy storage element. Comparative Example 3, which did not use ammonium bicarbonate, exhibited good shape retention, but its energy storage capacity was significantly reduced, and its strain was also higher.

[0066] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.

Claims

1. A method for preparing an energy storage element, characterized in that, The process includes the following steps: curing raw materials including energy storage materials, materials forming an elastic matrix, thermally conductive materials, and pore-forming agents; The pore-forming agent is ammonium bicarbonate, and the materials forming the elastic matrix include organosilicon polymers and curing agents; The energy storage element includes an elastic matrix; energy storage material and thermally conductive material are dispersed within the elastic matrix, and pores are distributed within the elastic matrix, the volume of which is 25-35% of the volume of the energy storage element; The energy storage material D 50 The diameter of the thermally conductive material is 80–120 μm. 50 The size is 40–120 μm; Under the same test conditions, the energy storage capacity of the energy storage element is M, the energy storage capacity of the energy storage material contained in the energy storage element is m, and M ≥ 0.95m.

2. The preparation method according to claim 1, characterized in that, A first mixture containing an organosilicon polymer and an energy storage material is mixed with a second mixture containing a thermally conductive material, a solid pore-forming agent, and a curing agent, and then vacuumed at 50–90°C for 15–50 minutes.

3. The preparation method according to claim 1, characterized in that, The energy storage material is selected from one or more of the following: rare earth hydrogen storage alloys, titanium hydrogen storage alloys, magnesium hydrogen storage alloys, vanadium-based solid solutions, coordination hydrides, metal nitrides, and carbon-based hydrogen storage materials. The thermally conductive material is selected from one or more of metallic thermally conductive materials and carbon-based thermally conductive materials.

4. The preparation method according to claim 1, characterized in that, The elastic matrix is ​​1 to 50 parts by weight, the energy storage material is 1 to 500 parts by weight, and the thermally conductive material is 0.5 to 50 parts by weight.

5. Use of the energy storage element prepared according to any one of claims 1 to 4 in storing hydrogen.

Images