High-safety fast-burning speed ignition paper for thermal battery and preparation method and application thereof

Abstract

The scheme discloses a high-safety fast-burning speed ignition paper for thermal battery, which belongs to the technical field of thermal battery and comprises a fast-burning speed ignition layer and a passivation layer, wherein the fast-burning speed ignition layer comprises a base material and a fast ignition agent, and the passivation layer comprises a passivation agent, the passivation agent is a metal oxide, the base material comprises a fiber material and a water-soluble adhesive, the fiber material comprises Al2O3 fibers, SiO2 fibers, MgF2 fibers or MgO fibers, and the water-soluble adhesive comprises styrene-butadiene rubber (SBR), hydroxymethyl cellulose (CMC), polytetrafluoroethylene emulsion (PTFE) or polyacrylate (PAA). The ignition paper is high in safety and fast in burning speed.

Description

Technical Field

[0001] This invention relates to the field of thermal battery technology, and in particular to a high-safety, fast-burning ignition paper for thermal batteries, its preparation method, and its application. Background Technology

[0002] Thermal batteries, as primary storage batteries, use inorganic electrolytes as separators and possess advantages such as high specific energy and high specific power, wide operating temperature range, and strong environmental adaptability, thus occupying an important position in military energy. A thermal battery mainly consists of an activation and ignition system, a stack power supply system, and a thermal insulation system. The activation and ignition system mainly includes an activation source (electric igniter or primer, etc.) and ignition paper. The stack power supply system mainly includes a positive electrode (FeS2, CoS2), an inorganic salt separator (LiCl-KCl, LiF-LiCl-LiBr), a negative electrode (LiB, LiSi), and heating powder (Fe-KClO4). The thermal insulation system mainly consists of asbestos paper and heat-insulating paper.

[0003] Thermal batteries differ from aqueous batteries and solid-state batteries mainly in their use of inorganic lithium salts. Their key characteristics are: 1) After melting, solid lithium salts exhibit high ionic conductivity, more than 10 times that of conventional batteries, enabling thermal batteries to discharge at high currents and be used as high-power chemical power sources; 2) Long storage time (20 years) because the electrolyte is solid at room temperature, there is no ion exchange between the positive and negative electrodes, preventing performance degradation and requiring no maintenance; 3) Metallic lithium is a commonly used negative electrode material in thermal batteries, with a relatively low electrode potential and strong electron transfer capability.

[0004] Thermal battery activation is divided into electrical activation and mechanical activation. Regardless of the method, the ignition paper is ignited, which in turn ignites the heating element inside the battery. The heat from the burning heating element melts the inorganic electrolyte membrane from a solid state to a liquid state, forming an "ionic conductive bridge" between the positive and negative electrodes, thus enabling the thermal battery to start working. With the rapid development of military equipment, especially the development of new weapon systems, faster activation times and higher mechanical conditions are required for thermal batteries. Thermal batteries must possess mechanical insensitivity and rapid activation characteristics, making the high safety and rapid combustion properties of the ignition paper particularly noteworthy.

[0005] For example, CN103821027B discloses ignition paper and its preparation method. The preparation method includes the following steps: S1, preparing the reducing agent zirconium: including zirconium powder washing → zirconium powder drying → zirconium powder sieving; S2, preparing the oxidizing agent lead dioxide: including lead dioxide drying → lead dioxide sieving; S3, preparing the binder: mixing polyvinyl alcohol with water to form a polyvinyl alcohol solution, which serves as the binder; S4, preparing the ignition paper: including composing the ignition paper material with the oxidizing agent, reducing agent, and asbestos paper → adding water to fuse the ignition paper material → adding the binder → stirring → pulping → papermaking → drying. In this invention, the oxidizing agent used in the ignition paper is lead dioxide, a peroxide, while the oxidizing agent used in ordinary ignition paper is barium chromate, an oxidizing salt. Peroxides have higher oxidizing activity; therefore, this ignition paper has a higher reaction rate and a lower reaction energy barrier, exhibiting a faster linear burning rate and better low-temperature adaptability. However, lead dioxide is a highly toxic substance and a Group 2A carcinogen, posing a significant hazard to operators and the environment. Furthermore, due to its high reactivity and poor chemical stability, it may lead to accidental activation without other preventative measures.

[0006] For example, CN109438148A discloses a high-burning-rate pyrotechnic agent for activating thermal batteries, its preparation method, and its application. The pyrotechnic agent consists of an oxidant, a reducing agent, and a molding binder; the oxidant is composed of potassium chlorate and lead chromate, and its preparation method is also disclosed. Applied to the activation of thermal batteries, it features rapid burning rate, reliable activation, no ignition skipping, no micro-short circuits, and safe and convenient use. It can activate thermal batteries more quickly, fully meeting the rapid activation requirements of thermal batteries, and is suitable for thermal batteries in rapid response and other fields, especially for rapid activation of thermal batteries. However, both the reducing agent and oxidant in the pyrotechnic agent contain lead-based inorganic substances. Furthermore, the preparation method involves coating the slurry onto asbestos paper, drying it, and forming it into high-burning-rate ignition paper. This method easily leads to uneven distribution of the pyrotechnic agent on the asbestos paper, and also fails to solve the problem of excessively high friction of the ignition paper.

[0007] For example, CN113322115A discloses a composite ignition paper for thermal batteries and its preparation method. The composite ignition paper has a double-layer structure, consisting of an ignition paper layer and a combustion-supporting layer, which are bonded together. The ignition paper layer is a zirconium-barium chromate-potassium perchlorate type ignition paper, and the combustion-supporting agent is aluminum foil, alumina, mica sheets, or kraft paper, etc. The composite ignition paper provided by this invention has the characteristic of significantly improving the linear burning rate of the ignition paper, and is particularly suitable for thermal batteries with short activation time requirements. In this invention, excessively high temperatures cause the combustion-supporting agent aluminum foil to melt, resulting in a short circuit in the individual thermal battery cells. Furthermore, the combustion-supporting layer, made of alumina, mica sheets, or kraft paper, is a non-combustible material, and its combustion-supporting effect is not significant.

[0008] Since the invention of thermal batteries, research on them has remained fervent worldwide, leading to rapid development. However, due to the specific nature of their applications, there has been limited reporting on thermal batteries, especially regarding their core component—ignition paper. In today's increasingly competitive international landscape, with the continuous development of new technologies and equipment, the high safety and rapid ignition of thermal battery ignition paper are particularly crucial. Summary of the Invention

[0009] The present invention aims to provide a high-safety, fast-burning ignition paper for thermal batteries, its preparation method and application, in order to solve the problem of slow ignition speed of existing ignition papers.

[0010] This solution discloses a high-safety fast-ignition paper for thermal batteries, comprising a fast-ignition layer and a passivation layer. The fast-ignition layer comprises a substrate and a fast igniter, and the passivation layer comprises a passivation agent, wherein the passivation agent is a metal oxide. The substrate comprises a fiber material and a water-soluble adhesive in a mass ratio of (1~5):(95~99). The fiber material comprises Al2O3 fiber, SiO2 fiber, MgF2 fiber, or MgO fiber, and the water-soluble adhesive comprises styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polytetrafluoroethylene emulsion (PTFE), or polyacrylate (PAA).

[0011] Furthermore, the passivating agent is one or more of MgO, MgF2, SiO2 and TiO2.

[0012] Furthermore, the rapid igniter is a catalyst, oxidant, reducing agent, and combustion promoter.

[0013] Furthermore, the catalyst is CuO, Fe2O3, or Co2O3.

[0014] Furthermore, the oxidant is BaCrO4 or CaCrO4.

[0015] Furthermore, the reducing agent is Zr or Fe.

[0016] Furthermore, the combustion promoter is KClO4, LiClO4, or NaClO4.

[0017] Furthermore, the mass percentages of catalyst, oxidant, reducing agent, and combustion promoter are: (1%–5%): (15%–50%): (15%–50%): (15%–40%).

[0018] A method for preparing a high-safety, fast-ignition paper for thermal batteries, comprising two parts: a fast-ignition layer and a passivation layer, including the following steps:

[0019] S1. Add the water-soluble adhesive to deionized water and stir thoroughly at 5000 r / min to 20000 r / min for 5 min to 30 min to obtain the water-soluble adhesive. Then add the fiber material and stir again to obtain the substrate.

[0020] S2. Weigh and add the catalyst and combustion accelerator to the substrate in sequence, and stir thoroughly at 500 r / min to 1000 r / min for 5 min to 30 min. Then add the oxidant and reducing agent, and stir thoroughly again at 300 r / min to 500 r / min for 5 min to 30 min to ensure that the raw materials are fully mixed and uniform, which is conducive to the molding of the substrate and the uniform distribution of the igniter.

[0021] S3. Use a wet forming machine to form a uniformly distributed material, place the obtained material on a flat dryer for drying, the drying temperature is 80℃~130℃, and the material is dried in the flat dryer for 10min~30min to obtain a fast-burning ignition layer.

[0022] S4. Supersonic low-pressure cold spraying technology is adopted. One or more of MgO, MgF2, SiO2 and TiO2 are mechanically mixed uniformly to form a spraying powder. A passivation layer is prepared using compressed air as a carrier and uniformly sprayed onto the fast-ignition layer. The spraying gas pressure is 0.5MPa~1.5MPa, the spraying temperature is 500℃~600℃, and the spraying distance is 5mm~20mm, resulting in a high-safety fast-ignition paper.

[0023] An application of a high-safety, fast-ignition ignition paper for thermal batteries, wherein the ignition paper serves as the ignition paper for the thermal battery. The fast-ignition layer is in close proximity to the thermal battery stack, and the passivation layer is in close proximity to the encapsulation layer.

[0024] The working principle of this solution is as follows: This invention divides the thermal battery ignition paper into a fast-burning ignition layer and a passivation layer. The fast-burning ignition layer increases the burning rate of the ignition paper by adding catalysts and combustion promoters. The passivation layer is located on the outer part of the ignition paper, which reduces the friction sensitivity of the ignition paper. At the same time, the passivation agent has strong adsorption properties, which increases the chemical stability of the ignition layer.

[0025] The beneficial effects of this invention are:

[0026] 1. The added metal oxide catalysts and combustion improvers are non-toxic and harmless, which is beneficial to the health of operators and environmental protection;

[0027] 2. A new method for preparing ignition paper is adopted, which disperses the active material more evenly, increases the burning rate, and reduces the preparation process of ignition paper;

[0028] 3. The passivation layer adopts supersonic low-pressure cold spraying technology, which has a simple process, and the particles inside the passivation layer are tightly bonded, resulting in a dense coating with low porosity. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a high-safety, fast-burning ignition paper for thermal batteries according to the present invention;

[0030] Figure 2 This is a schematic diagram illustrating the use of a high-safety, fast-burning ignition paper for thermal batteries according to the present invention. Detailed Implementation

[0031] The following detailed explanation illustrates the specific implementation methods:

[0032] Example 1:

[0033] A method for preparing high-safety, fast-burning ignition paper for thermal batteries, the specific preparation steps are as follows:

[0034] S1. Add 5% by weight of hydroxymethyl cellulose (CMC) to deionized water and stir thoroughly at 5000 r / min for 5 min to obtain a water-soluble adhesive. Then add 95% by weight of Al2O3 fiber and stir again to obtain the substrate.

[0035] S2. Weigh and add 2% by mass of catalyst CuO and 18% by mass of combustion accelerator KClO4 to the substrate in sequence, stir thoroughly at 500 r / min for 5 min, then add 35% by mass of oxidant BaCrO4 and 45% by mass of reducing agent Zr, and stir thoroughly again at 300 r / min for 6 min to ensure that the raw materials are fully mixed and uniform, which is conducive to substrate molding and uniform distribution of igniter substances.

[0036] S3. Use a wet forming machine to form a uniformly distributed material, place the obtained material on a flat dryer for drying at 100℃ for 10 minutes to obtain a fast-burning ignition layer.

[0037] S4. Supersonic low-pressure cold spraying technology is adopted. MgO, the passivating agent, is used as the spraying powder through mechanical mixing. Compressed air is used as the carrier to prepare the passivation layer, which is then uniformly sprayed onto the fast-ignition layer. The spraying gas pressure is 0.6MPa, the spraying temperature is 550℃, and the spraying distance is 10mm, resulting in high-safety fast-ignition paper.

[0038] Example 2:

[0039] A method for preparing high-safety, fast-burning ignition paper for thermal batteries, the specific preparation steps are as follows:

[0040] S1. Add 4% by mass of styrene-butadiene rubber (SBR) to deionized water and stir thoroughly at 8000 r / min for 8 min to obtain a water-soluble adhesive. Then add 96% by mass of MgF2 fiber and stir again to obtain the substrate.

[0041] S2. Weigh and add 3% by mass of catalyst CuO and 30% by mass of combustion accelerator NaClO4 to the substrate in sequence, stir thoroughly at 600 r / min for 8 min, then add 32% by mass of oxidant BaCrO4 and 35% by mass of reducing agent Zr, and stir thoroughly again at 400 r / min for 10 min to ensure that the raw materials are fully mixed and uniform, which is conducive to substrate molding and uniform distribution of igniter substances.

[0042] S3. Use a wet forming machine to form a uniformly distributed material, place the obtained material on a flat dryer for drying at 110℃ for 15 minutes to obtain a fast-burning ignition layer.

[0043] S4. Supersonic low-pressure cold spraying technology is adopted. A passivation layer is prepared using 35% MgO and 65% MgF2 as spraying powders via mechanical mixing, with compressed air as the carrier. This passivation layer is then uniformly sprayed onto the fast-ignition layer. The spraying gas pressure is 0.8 MPa, the spraying temperature is 580℃, and the spraying distance is 12 mm, resulting in a high-safety, fast-ignition paper.

[0044] Example 3:

[0045] A method for preparing high-safety, fast-burning ignition paper for thermal batteries, the specific preparation steps are as follows:

[0046] S1. Add 2% by mass of polytetrafluoroethylene emulsion (PTFE) to deionized water and stir thoroughly at 10000 r / min for 10 min to obtain a water-soluble adhesive. Then add 98% by mass of MgO fiber and stir again to obtain the substrate.

[0047] S2. Weigh and add 5% by mass of catalyst Fe2O3 and 50% by mass of combustion accelerator LiClO4 to the substrate in sequence, and stir thoroughly at 800 r / min for 30 min. Then add 30% by mass of oxidant CaCrO4 and 15% by mass of reducing agent Fe, and stir thoroughly again at 350 r / min for 15 min to ensure that the raw materials are fully mixed and uniform, which is conducive to substrate molding and uniform distribution of igniter substances.

[0048] S3. Use a wet forming machine to form a uniformly distributed material, place the obtained material on a flat dryer for drying at 125℃ for 20 minutes to obtain a fast-burning ignition layer.

[0049] S4. Supersonic low-pressure cold spraying technology is adopted. A passivation layer is prepared by mechanically mixing SiO2 (50% by mass) and TiO2 (50% by mass) as spraying powders, using compressed air as a carrier. This passivation layer is then uniformly sprayed onto the fast-ignition layer. The spraying gas pressure is 1.2 MPa, the spraying temperature is 600℃, and the spraying distance is 15 mm, resulting in a high-safety, fast-ignition paper.

[0050] Example 4:

[0051] A method for preparing high-safety, fast-burning ignition paper for thermal batteries, the specific preparation steps are as follows:

[0052] S1. Add 3% by mass of polyacrylate (PAA) to deionized water and stir thoroughly at 15000 r / min for 25 min to obtain a water-soluble adhesive. Then add 97% by mass of MgO fiber and stir again to obtain the substrate.

[0053] S2. Weigh and add 2% by mass of catalyst Co2O3 and 15% by mass of combustion accelerator NaClO4 to the substrate in sequence, and stir thoroughly at 700 r / min for 18 min. Then add 40% by mass of oxidant BaCrO4 and 43% by mass of reducing agent Fe, and stir thoroughly again at 350 r / min for 15 min to ensure that the raw materials are fully mixed and uniform, which is conducive to substrate molding and uniform distribution of igniter substances.

[0054] S3. Use a wet forming machine to form a uniformly distributed material, place the obtained material on a flat dryer for drying at 130℃ for 18 minutes to obtain a fast-burning ignition layer.

[0055] S4. Supersonic low-pressure cold spraying technology is adopted. A passivation layer is prepared using MgO (42% by mass) and TiO2 (58% by mass) as the spraying powder, with compressed air as the carrier. This passivation layer is then uniformly sprayed onto the fast-ignition layer. The spraying gas pressure is 1.5 MPa, the spraying temperature is 600℃, and the spraying distance is 20 mm, resulting in a high-safety, fast-ignition paper.

[0056] The ignition paper produced in Examples 1-4 is an adjunct. Figure 1 As shown;

[0057] The applications of the ignition paper produced in Examples 1-4 as ignition paper for thermal batteries are shown in the appendix. Figure 2 As shown.

[0058] The measured burning rates of the high-safety, fast-burning ignition paper in Examples 1-4 are shown in the table below:

[0059] Table 1 Burn Rate Table

[0060]

[0061] The high-safety, fast-ignition ignition paper was tested in a drop weight friction sensitivity meter with a friction load of 280N, and no ignition phenomenon was observed in the high-safety ignition paper.

[0062] Comparative Example 1

[0063] Unlike Example 1, conventional ignition paper was prepared using Zr and BaCrO4, and the burning rate was measured to be 185 cm / s.

[0064] When conventional ignition paper was tested in a drop weight friction sensitivity meter with a friction load of 280N, the conventional ignition paper spontaneously combusted.

[0065] As can be seen from the examples and Comparative Example 1, the use of high-safety, fast-burning ignition paper has a better burning rate and friction resistance. In addition, a novel ignition paper preparation method is proposed, which reduces the preparation process and uses more environmentally friendly lead-free compounds, making it safer and more environmentally friendly.

[0066] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A high-safety, fast-burning ignition paper for thermal batteries, characterized in that: The system includes a fast-ignition layer and a passivation layer. The fast-ignition layer comprises a substrate and a fast igniter. The fast igniter is a catalyst, an oxidant, a reducing agent, and a combustion promoter. The catalyst is CuO, Fe2O3, or Co2O3; the oxidant is BaCrO4 or CaCrO4; the reducing agent is Zr or Fe; and the combustion promoter is KClO4, LiClO4, or NaClO4. The mass ratio of the catalyst, oxidant, reducing agent, and combustion promoter is (1%–5%): (15%–5%). 0% ): (15%~50%) : (15%~40%), the passivation layer includes a passivating agent, which is one or more of MgO, MgF2, SiO2 and TiO2; the substrate includes fiber material and water-soluble adhesive in a mass ratio of (1~5): (95~99); the fiber material includes Al2O3 fiber, SiO2 fiber, MgF2 fiber or MgO fiber, and the water-soluble adhesive includes styrene-butadiene rubber, hydroxymethyl cellulose, polytetrafluoroethylene emulsion or polyacrylate.

2. The method for preparing a high-safety, fast-burning ignition paper for thermal batteries according to claim 1, characterized in that: It consists of two parts: a fast-burning ignition layer and a passivation layer, and includes the following steps: S1. Add the water-soluble adhesive to deionized water and stir thoroughly at 5000 r / min to 20000 r / min for 5 min to 30 min to obtain the water-soluble adhesive. Then add the fiber material and stir again to obtain the substrate. S2. Weigh and add the catalyst and combustion accelerator to the substrate in sequence, and stir thoroughly at 500 r / min to 1000 r / min for 5 min to 30 min. Then add the oxidant and reducing agent, and stir thoroughly again at 300 r / min to 500 r / min for 5 min to 30 min to ensure that the raw materials are fully mixed and uniform, which is conducive to the molding of the substrate and the uniform distribution of the igniter. S3. Use a wet forming machine to form a uniformly distributed material, place the obtained material on a flat dryer for drying, the drying temperature is 80℃~130℃, and the material is dried in the flat dryer for 10min~30min to obtain a fast-burning ignition layer. S4. Using supersonic low-pressure cold spraying technology, one or more of MgO, MgF2, SiO2 and TiO2 are mechanically mixed uniformly to form a spraying powder. A passivation layer is prepared using compressed air as a carrier and uniformly sprayed onto the fast-ignition layer. The spraying gas pressure is 0.5MPa~1.5MPa, the spraying temperature is 500℃~600℃, and the spraying distance is 5mm~20mm, resulting in a high-safety fast-ignition paper.

3. The application of the high-safety, fast-burning ignition paper for thermal batteries prepared by the method according to claim 2, characterized in that: The application of ignition paper as ignition paper in thermal batteries.

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