Thermal battery corrugated hole structure heat insulation material and preparation method thereof

Abstract

The application discloses a corrugated hole structure heat insulation material for a thermal battery and a preparation method thereof, and belongs to the technical field of preparation of heat insulation and heat preservation materials. The preparation method is characterized by taking 50-80% of inorganic mineral fiber and 50-20% of high-aluminum fiber cotton as raw materials, beating the raw materials, adding inorganic glue, preparing slurry, adopting a wet papermaking process of a side flow type rotary screen paper machine to cast the slurry into raw paper, adopting an organic-inorganic double-component adhesive to adhere the raw paper to flat raw paper on one side, and drying the raw paper to obtain the corrugated hole structure heat insulation material. The corrugated hole structure heat insulation material has low density, high strength, excellent winding flexibility and good heat insulation performance, and can better meet the application of small-diameter thermal batteries.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation material preparation technology, and in particular to a corrugated porous structure thermal insulation material for thermal batteries and its preparation method. Background Technology

[0002] A thermal battery, also known as a thermally activated battery, is a type of reserve power source. When not activated, a thermal battery maintains inertia and stability; once activated, it can typically output peak electrical energy within a short period. Due to its advantages such as small size, high specific power, wide applicable temperature and geographical range, long storage time, maintenance-free operation, and strong resistance to shock and vibration, thermal batteries are increasingly widely used as power sources for various military devices.

[0003] Structurally, a thermal battery consists of several battery cells (including positive electrode, negative electrode, electrolyte, etc.), ignition material, heat insulation material, and a metal sealing shell. Once activated, the thermal battery rapidly heats up to its operating temperature of 450℃~550℃, causing the electrolyte to melt and output current. Once the heat dissipates below the normal operating temperature, the battery's lifespan ends, and it stops supplying power.

[0004] In thermal battery modules, the insulating material is wound around the outside of the battery cell and placed inside a metal casing. It plays a crucial role in preventing heat loss, maintaining the normal operating temperature of the thermal battery, and extending its operating time. Commonly used insulating materials for thermal batteries include aerogel insulating paper, mineral fiber insulating paper, and aluminum silicate paper. Each of these materials has its own characteristics and shortcomings. For example, aerogel insulating paper has excellent thermal insulation performance, with a thermal conductivity of approximately 0.020 W / (m·K), but its strength is relatively poor and it is brittle. Insulating paper has good strength, but its thermal insulation performance is slightly worse, with a thermal conductivity of approximately 0.055 W / (m·K). For some small-diameter thermal batteries, none of the above insulating materials are ideal. On the one hand, if aerogel insulating paper with excellent thermal insulation performance is used, its poor strength and brittleness make it prone to breakage during winding. On the other hand, if insulating paper with high strength is used, the thickness of the insulating layer must be increased; otherwise, it will be difficult to meet the thermal insulation requirements. Summary of the Invention

[0005] This invention aims to prepare a thermal insulation material that combines good thermal insulation performance, superior strength and winding flexibility, low density and resistance to high temperatures above 600℃, in order to meet the requirements for use with thermal batteries.

[0006] To achieve the above-mentioned technical objectives, the present invention is implemented through the following technical solution:

[0007] A method for preparing a corrugated porous structure thermal insulation material for thermal batteries includes the following steps: Mineral fibers and high-alumina fiber cotton are used as main raw materials. After pulping and adding reinforcing agents, a pulp is prepared. This pulp is then formed into base paper using a side-flow cylinder paper machine wet papermaking process. The base paper is then rolled into corrugated paper using a corrugating machine, and the base paper is single-sided laminated with adhesive to produce the corrugated porous structure thermal insulation material for thermal batteries.

[0008] (1) Weigh out mineral fiber and high-alumina fiber cotton separately, with a total mass of 100 parts, of which the mineral fiber is 50-80 parts; add water and mineral fiber to a pulping machine in sequence, with the mineral fiber having a mass percentage concentration of 3%-5%, and pulp with a light knife until the freeness reaches 62. 0 SR~78 0 After the SR wet weight is 5g to 15g, remove the knife, add high alumina fiber cotton, continue to loosen for 10min to 15min, stop pulping, and put the pulp into the mixing tank;

[0009] (2) Add water to the slurry mixing tank to dilute the slurry to a consistency of 0.4wt% to 0.5wt%, and add 2% to 5% inorganic adhesive as a reinforcing agent based on the amount of fiber raw material. After thorough mixing, put the mixture into the pre-coating tank.

[0010] (3) The prepared pulp was produced by wet papermaking process using a side-flow cylinder paper machine to achieve a basis weight of 100 g / m³. 2 ~110g / m 2 Mineral fiber base paper with a thickness of 0.16mm to 0.18mm;

[0011] (4) The mineral fiber base paper from step (3) is rolled into corrugated paper on a corrugating machine, and the corrugated paper is bonded to the sheet mineral fiber base paper prepared in step (3) using an organic-inorganic two-component adhesive (the two are bonded on one side only). After drying at 105℃±5℃, a corrugated hole structure heat insulation material for thermal batteries is produced.

[0012] Further, in step (1), the mineral fiber is one of sepiolite fiber, asbestos fiber, and brucite fiber, and the high-alumina fiber cotton has an alumina content of ≥58% and a fiber diameter of 2μm~4μm.

[0013] Furthermore, in step (1), the total mass of mineral fiber and high-alumina fiber cotton is 100 parts, of which the mass of mineral fiber is 69-75 parts.

[0014] Furthermore, in step (2), the inorganic adhesive reinforcing agent is one of silica sol and alumina adhesive.

[0015] Furthermore, in step (3), the longitudinal tensile strength of the mineral fiber base paper is ≥0.5kN / m.

[0016] Further, in step (4), the organic-inorganic two-component adhesive is prepared by mixing commercially available polyvinyl acetate adhesive (also known as white glue) and alumina glue with a solid content of 20% at a mass ratio of 1:0.8-1.2, preferably at a mass ratio of 1:1, and then stirring thoroughly.

[0017] Furthermore, in step (4), the purpose of using an organic-inorganic two-component adhesive is mainly to take advantage of the high temperature resistance of inorganic adhesive and the good initial tack of organic adhesive. Because inorganic adhesive is resistant to high temperatures but has poor initial tack, if only inorganic adhesive is used, the corrugated paper and the sheet paper will not bond firmly. On the contrary, if only organic adhesive is used, the corrugated paper and the sheet paper will bond very well. However, before the use of the thermal battery, it needs to be heat-treated (the operating temperature of the thermal battery is 450℃~550℃. At such a temperature, the organic components decompose and will cause safety hazards. Therefore, the organic components are generally removed by pyrolysis at a temperature above 300℃). During the heat treatment process, the organic adhesive decomposes, which will cause the corrugated paper and the sheet paper to separate, and cannot meet the requirements for use. However, by using an organic-inorganic two-component adhesive, the requirement of strong bonding between the corrugated paper and the sheet paper is met. At the same time, during the heat treatment process, the organic adhesive decomposes, but the inorganic adhesive plays a good bonding role, thereby meeting the requirements for use.

[0018] The present invention also provides a corrugated porous structure thermal insulation material for thermal batteries prepared by the above method, wherein the thickness of the corrugated porous structure thermal insulation material for thermal batteries is 1.8 mm to 2.2 mm; and the apparent density is ≤178 kg / m³. 3 The rib spacing is 4mm to 5mm; the thermal conductivity is ≤0.037W / (m·k); the temperature resistance is maintained at 600℃ for 1 hour without significant changes in the material appearance; it has good flexibility and does not crack or break when wound on a Φ42mm cylindrical mold.

[0019] The beneficial features of this invention are:

[0020] 1) A thermal insulation material is made from high-temperature resistant mineral fiber base paper, which is then corrugated and laminated with a single-sided planar layer. Due to the high elasticity of the corrugated layer structure, this material effectively solves the flexibility problem encountered when winding thermal insulation materials for small-diameter thermal batteries, preventing breakage during assembly. Furthermore, this composite material of corrugated and planar layers creates pores comprising approximately 80% of the total volume of the composite material, resulting in a lower density. Since the air trapped within the pores is a poor conductor of heat, the material exhibits good thermal insulation properties. In addition, the planar layer of the thermal insulation material, besides supporting and shaping the porous layer, also acts as a heat shield to some extent, blocking a certain amount of radiative heat transfer, further enhancing the material's thermal insulation effect. Therefore, the corrugated porous structure thermal insulation material prepared by this invention simultaneously possesses high-temperature resistance, superior strength, winding flexibility, and excellent thermal insulation performance.

[0021] 2) The material formed by bonding the mineral fiber base paper to the corrugated paper on one side in this invention has a thermal conductivity ≤0.037W / (m·k). In contrast, the thermal conductivity of uncorrugated sheet paper is 0.050W / (m·k)~0.058W / (m·k), which is prone to breakage when used in small-diameter thermal batteries. Detailed Implementation

[0022] The present invention will be further described in detail below through embodiments. These embodiments will enable those skilled in the art to have a more comprehensive understanding of the present invention, but do not limit the present invention in any way.

[0023] In this embodiment of the invention, the high-alumina fiber cotton was purchased from Luoyang Refractory Materials Research Institute, and the commercially available polyvinyl acetate adhesive (also known as white glue) was a product of Henkel AG, brand name "Pattex". The silica sol was purchased from Shandong Baite New Materials Co., Ltd., and the alumina adhesive was purchased from Shandong Zibo Jinqi Chemical Co., Ltd.

[0024] Example 1

[0025] 75 kg of sepiolite fiber and 32 kg of high-alumina fiber cotton (alumina content ≥58%, fiber diameter 2μm~4μm) were weighed separately. The sepiolite fiber was placed in a pulper and 1425 kg of water was added. The pulp was then beaten with a light knife for 30 minutes. The measured freeness was 72. 0 When the SR (Solar Surface Finish) has a wet weight of 6.1g, the pulp is started, high-alumina fiber cotton is added, and the pulping continues for 10 minutes. Beating is then stopped, and the pulp is placed in the mixing tank. Water is added to the mixing tank to dilute the pulp to a consistency (mass percentage concentration) of 0.5%, and 4% alumina glue (based on the fiber raw material) is added as a reinforcing agent. After thorough mixing for 25 minutes, the pulp is placed in the pre-papermaking tank. Wet papermaking is performed using a side-flow cylinder paper machine to produce a paper with a basis weight of 110g / m³. 2The mineral fiber base paper has a thickness of 0.18 mm and a tensile strength (longitudinal) of 0.65 kN / m. The mineral fiber base paper is rolled into corrugated paper using a corrugating machine. An organic-inorganic two-component adhesive, prepared by mixing commercially available polyvinyl acetate adhesive (also known as white glue) and alumina adhesive with a solid content of 20% in a 1:1 mass ratio, is used to bond the corrugated paper and mineral fiber base paper on one side. The mixture is then dried at 105°C to produce a corrugated porous structure thermal insulation material for thermal batteries.

[0026] The insulation material prepared in Example 1 has a thickness of 2.2 mm and an apparent density of 176 kg / m³. 3 The pitch of the flutes is 5mm; the thermal conductivity is 0.035W / (m·k); the sample showed no significant change after a 1-hour temperature resistance test at 600℃; the sample did not crack or break when wound on a Φ42mm cylindrical mold, and it exhibited good flexibility.

[0027] Example 2

[0028] 60 kg of brucite fiber and 26 kg of high-alumina fiber cotton (alumina content ≥58%, fiber diameter 2μm~4μm) were weighed separately. The brucite fiber was placed in a pulper and 1440 kg of water was added. The pulp was then beaten with a light knife for 60 minutes. The measured freeness was 75. 0 When the SR (slippery fiber) has a wet weight of 7.1g, the pulp is started, high-alumina fiber cotton is added, and the pulping continues for 13 minutes. Beating is then stopped, and the pulp is placed in the mixing tank. Water is added to the mixing tank to dilute the pulp to a consistency (mass percentage concentration) of 0.45%, and 4% silica sol (based on the fiber raw material weight) is added as a reinforcing agent. After thorough stirring for 30 minutes, the pulp is placed in the pre-papermaking tank. Wet papermaking is performed using a side-flow cylinder paper machine to produce a paper with a basis weight of 106g / m³. 2 A mineral fiber base paper with a thickness of 0.17 mm and a tensile strength (longitudinal) of 0.61 kN / m was used. The mineral fiber base paper was rolled into corrugated paper using a corrugating machine. A two-component organic-inorganic adhesive, prepared by mixing commercially available polyvinyl acetate adhesive (also known as white glue) and alumina adhesive with a solid content of 20% at a 1:1 mass ratio, was used to bond the corrugated paper and the mineral fiber base paper on one side. The mixture was then dried at 110°C to produce a corrugated porous structure thermal insulation material for thermal batteries. The thermal insulation material produced in this example has a thickness of 2.0 mm, an apparent density of 169 kg / m³, a flute pitch of 4.5 mm, and a thermal conductivity of 0.034 W / (m·K). After a 1-hour temperature resistance test at 600°C, the sample showed no significant changes. The sample did not crack or break when wound onto a Φ42 mm cylindrical mold, demonstrating good flexibility.

[0029] Example 3

[0030] Weigh out 45 kg of asbestos fiber and 19 kg of high-alumina fiber cotton (alumina content ≥58%, fiber diameter 2μm~4μm). Put the asbestos fiber into a pulper and add 1455 kg of water. Pulp under light blade for 90 minutes. The measured freeness is 78. 0 When the SR (Solar Surface Finish) has a wet weight of 9.8g, the pulp is started, high-alumina fiber cotton is added, and the pulping continues for 15 minutes. Beating is then stopped, and the pulp is placed in the mixing tank. Water is added to the mixing tank to dilute the pulp to a consistency (mass percentage concentration) of 0.4%, and silica sol (4% of the fiber raw material weight) is added as a reinforcing agent. After thorough stirring for 20 minutes, the pulp is placed in the pre-papermaking tank. Wet papermaking is performed using a side-flow cylinder paper machine to produce a paper with a basis weight of 100g / m³. 2 A mineral fiber base paper with a thickness of 0.16 mm and a tensile strength (longitudinal) of 0.58 kN / m was used. The mineral fiber base paper was rolled into corrugated paper using a corrugating machine. A two-component organic-inorganic adhesive, prepared by mixing commercially available polyvinyl acetate adhesive (also known as white glue) and alumina adhesive with a solid content of 20% at a 1:1 mass ratio, was used to bond the corrugated paper and the mineral fiber base paper on one side. The mixture was then dried at 100°C to produce a corrugated porous structure thermal insulation material for thermal batteries. The thermal insulation material produced in this example has a thickness of 1.8 mm, an apparent density of 162 kg / m³, a flute pitch of 4 mm, and a thermal conductivity of 0.033 W / (m·K). After a 1-hour temperature resistance test at 600°C, the sample showed no significant changes. The sample did not crack or break when wound onto a Φ42 mm cylindrical mold, demonstrating good flexibility.

[0031] Compare with Example 1:

[0032] Weigh out 45 kg of asbestos fiber and 19 kg of high-alumina fiber (alumina content ≥58%, fiber diameter 2μm~4μm). Place the asbestos fiber in a pulper and add 1455 kg of water. Pulping is done with a light blade for 90 minutes. When the measured freeness is 780SR and the wet weight is 9.8 g, the blade is removed, and the high-alumina fiber is added. Pulping continues for 15 minutes, then the pulping is stopped, and the pulp is placed in a mixing tank. Water is added to the mixing tank to dilute the pulp to a pulp concentration (mass percentage concentration) of 0.4%. 4% of the fiber raw material weight of silica sol is added as a reinforcing agent. After stirring thoroughly for 20 minutes, the pulp is placed in a pre-washing tank. Paper was produced using a side-flow cylinder paper machine with a wet papermaking process, yielding mineral fiber papers with thicknesses of 0.5 mm and 1.0 mm. Their thermal conductivity was measured to be 0.512 W / (m·K) and 0.538 W / (m·K), respectively. Winding tests were conducted using a Φ42 mm cylindrical die with both paper thicknesses. Due to the brittleness and poor bending properties of inorganic fiber paper, the test results showed that the 0.5 mm thick mineral fiber paper developed fine cracks after winding, posing a certain risk despite not breaking. The 1.0 mm thick mineral fiber paper, however, exhibited more noticeable cracks after winding.

Claims

1. A method for preparing a corrugated porous structure thermal insulation material for thermal batteries, characterized by using... Mineral fiber and high-alumina fiber cotton are used as the main raw materials. After pulping and adding inorganic reinforcing agents, the pulp is prepared into a base paper using a side-flow cylinder paper machine wet papermaking process. The base paper is then rolled into corrugated paper using a corrugating machine and laminated onto a single side of the base paper using an organic-inorganic two-component adhesive. This process produces a corrugated porous structure thermal insulation material for thermal batteries, including the following steps: (1) Weigh out mineral fiber and high-alumina fiber cotton separately, with a total mass of 100 parts, of which the mineral fiber is 50-80 parts; add water and mineral fiber to a pulper in sequence, with the mineral fiber having a mass percentage concentration of 3%~5%, and beat with a light knife until the freeness reaches 62. 0 SR~78 0 After the SR wet weight is 5 g to 15 g, remove the knife, add high alumina fiber cotton, continue to loosen for 10 min to 15 min, stop pulping, and put the pulp into the mixing tank; (2) Add water to the slurry mixing tank to dilute the slurry to a consistency of 0.4wt%~0.5wt%, and add 2%-5% inorganic adhesive as a reinforcing agent based on the amount of fiber raw material. After thorough mixing, put it into the pre-coating tank. (3) The prepared pulp was produced by wet papermaking process using a side-flow cylinder paper machine to achieve a basis weight of 100 g / m³. 2 ~110g / m 2 Mineral fiber base paper with a thickness of 0.16mm~0.18mm; (4) The mineral fiber base paper from step (3) is rolled into corrugated paper on a corrugating machine, and the corrugated paper is bonded to the flat sheet of mineral fiber base paper prepared in step (3) using an organic-inorganic two-component adhesive. After drying at 105℃±5℃, it is made into a corrugated hole structure heat insulation material for thermal batteries. In step (1), the mineral fiber is one of sepiolite fiber, asbestos fiber, and brucite fiber, and the high-alumina fiber cotton has an alumina content of ≥58% and a fiber diameter of 2µm~4µm. In step (4), the organic-inorganic two-component adhesive is prepared by mixing commercially available polyvinyl acetate adhesive and alumina adhesive with a solid content of 20% at a mass ratio of 1:0.8-1.2, and then stirring thoroughly.

2. The method for preparing a corrugated porous structure thermal insulation material for a thermal battery as described in claim 1, characterized in that, In step (1), the total mass of mineral fiber and high-alumina fiber cotton is 100 parts, of which the mass of mineral fiber is 69-75 parts.

3. The method for preparing a corrugated porous structure thermal insulation material for a thermal battery as described in claim 1, characterized in that, In step (2), the inorganic adhesive reinforcing agent is one of silica sol and alumina adhesive.

4. The method for preparing a corrugated porous structure thermal insulation material for a thermal battery as described in claim 1, characterized in that, In step (3), the longitudinal tensile strength of the mineral fiber base paper is ≥0.5kN / m.

5. The method for preparing a corrugated porous structure thermal insulation material for a thermal battery as described in claim 1, characterized in that, In step (4), commercially available polyvinyl acetate adhesive and alumina adhesive with a solid content of 20% are mixed at a mass ratio of 1:

1.

6. The corrugated perforated thermal insulation material for thermal batteries prepared by the method according to any one of claims 1 to 5.

7. The corrugated perforated thermal insulation material for thermal batteries as described in claim 6, characterized in that, The thickness of the corrugated perforated thermal insulation material used in the thermal battery is 1.8mm~2.2mm; apparent density is ≤178kg / m³. 3 The rib spacing is 4mm~5mm; the thermal conductivity is ≤0.037W / (m·k); the temperature resistance is maintained at 600℃ for 1 hour without significant changes in the material appearance; it has good flexibility and does not crack or break when wound on a Φ42mm cylindrical mold.