An ignition material for thermal batteries and its preparation method

Abstract

This invention provides an ignition material for thermal batteries and its preparation method. The ignition material comprises barium chromate, zirconium powder, asbestos loosening paper, and glass fiber, wherein the mass percentage of barium chromate is 62%-75%, the mass percentage of zirconium powder is 22-35%, the mass percentage of asbestos loosening paper is 1-2%, and the mass percentage of glass fiber is 1-2%. The preparation method comprises: Step 1, crushing the asbestos loosening paper, glass fiber, and deionized water in a blender to prepare a slurry, and preparing a barium chloride solution by placing barium chloride and deionized water in a water bath; Step 2, stirring the slurry, zirconium powder, chromate, and deionized water in a water bath to prepare a precursor mixture; Step 3, adjusting the pH to 1 by adding concentrated hydrochloric acid to the precursor mixture, and then titrating the barium chloride solution into the precursor mixture while stirring; Step 4, forming the mixture and drying it. The ignition material for thermal batteries of this invention features uniform burning rate, good insulation, and high structural strength.

Description

Technical Field

[0001] This invention relates to the field of materials chemistry, specifically to an ignition material for thermal batteries and its preparation method. Background Technology

[0002] A thermal battery is a primary storage battery that uses its own heating material to heat and melt a solid salt electrolyte that is non-conductive at room temperature, turning it into an ionic conductor to output electrical energy. Thermal batteries have advantages such as long storage life, high output power, and rapid activation, making them particularly suitable for power supplies for various missile and weapon systems, and thus of great significance in the military field. Its working principle is as follows: an external signal detonates the electric igniter, which ignites the ignition material. The ignition material then ignites each heating element layer by layer. The combustion of the heating elements melts the electrolyte in each cell, turning it into an ionic conductor. The anode and cathode materials undergo a redox reaction through the molten electrolyte to generate electrical energy. The current is transported through the guide strip to the current-conducting column on the cover, and the thermal battery begins to output current. The internal temperature of a thermal battery during operation is between 450℃ and 550℃. It features high output power, short activation time, fast response, stable voltage, long storage life, and strong environmental adaptability, and is widely used in various missile weapons.

[0003] Currently, there are some related literature reports on ignition materials for thermal batteries. For example, in patent application CN103821027A (invention title: ignition paper and its preparation method), an ignition paper and its preparation method are disclosed. The ignition material prepared by this method has exposed active zirconium powder, which makes the material conductive and poses a risk of short circuit in the thermal battery stack.

[0004] The method disclosed in patent application CN109837806A (Invention title: A method for improving the safety of ignition paper preparation) has poor dispersion of active materials, resulting in poor uniformity of burning rate, poor material structural strength, and insufficient engineering applicability. These materials do not fundamentally solve the problem of the difficulty in reconciling the reliability and engineering applicability of thermal battery ignition materials. Summary of the Invention

[0005] The problem addressed by this invention is the difficulty in reconciling the reliability and engineering applicability of thermal battery ignition materials in the prior art. To solve this problem, this invention provides a highly reliable ignition material for thermal batteries with uniform burning rate, good insulation, and high structural strength, as well as its preparation method.

[0006] This invention provides a thermal battery ignition material, characterized in that it comprises: barium chromate, zirconium powder, asbestos loosening paper, and glass fiber, wherein the mass percentage of barium chromate is 62%-75%, the mass percentage of zirconium powder is 22-35%, the mass percentage of asbestos loosening paper is 1-2%, and the mass percentage of glass fiber is 1-2%.

[0007] Furthermore, the zirconium powder raw material used contains more than 92% active zirconium, which is zero-valent metallic zirconium, and the barium chromate is obtained by a precipitation reaction between barium chloride and chromate solution.

[0008] The present invention also provides a method for preparing the above-mentioned thermal battery ignition material, characterized in that it includes:

[0009] Step 1: Place the asbestos loosened paper, glass fiber, and deionized water in a high-speed blender to crush and prepare a pulp. Place barium chloride and deionized water in a water bath to prepare a barium chloride solution.

[0010] Step 2: Place the slurry, zirconium powder, chromate, and deionized water in a water bath and stir to prepare the precursor mixture;

[0011] Step 3: Add concentrated hydrochloric acid to the precursor mixture to adjust the pH to 1, then titrate the barium chloride solution into the precursor mixture while maintaining stirring in a water bath;

[0012] Step 4: Transfer the mixture in the water bath to the paper machine for forming. After drying the formed material, the thermal battery ignition material is obtained.

[0013] Furthermore, in step one, the crushing speed is 22000 r / min and the crushing time is 10 min.

[0014] Furthermore, in step one, the slurry concentration is 5 g / L, the water bath temperature is 60°C, and the barium chloride solution concentration is 1 mol / L.

[0015] Furthermore, in step two, the concentration of chromate ions in the precursor mixture is 1 mol / L.

[0016] Furthermore, in step three, the titration rate of the barium chloride solution is controlled at 1-2 ml / s, and after titration, the solution is stirred in a water bath for 10 minutes.

[0017] Furthermore, in step four, the material forming process involves removing moisture from the paper machine in one go before forming the material.

[0018] Furthermore, in step four, the drying temperature is 60℃-75℃, and the drying time is 12h-18h.

[0019] Furthermore, in step four, the molding thickness of the ignition material is 0.3mm-0.4mm.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] 1. This invention improves the uniformity of the active material and the material matrix by pre-mixing active zirconium powder with asbestos paper and glass fiber, thereby improving the uniformity of the combustion rate of the ignition material.

[0022] 2. In this invention, by adjusting the pH value of the solution, the barium chromate heteronuclear crystals generated in the reaction are coated on the surface of the zirconium powder, which further improves the uniformity of the active material and reduces the conductivity of the active material, thereby improving the reliability of the ignition material.

[0023] 3. This invention is the first to add glass fiber to replace conventional binders, thereby improving the structural strength of the ignition material and increasing its utilization rate. Detailed Implementation

[0024] The present invention will be further illustrated below through examples.

[0025] Example 1

[0026] Obtain thermal battery ignition material sample A according to the following steps:

[0027] Step 1: Place 1g of asbestos loosened paper, 2g of glass fiber, and deionized water in a high-speed blender and blend for 10 minutes at 22000r / min to prepare a slurry with a concentration of 5g / L. Place barium chloride and 500ml of deionized water in a 60℃ electromagnetic water bath to prepare a barium chloride solution with a concentration of 1mol / L and transfer it to a burette.

[0028] Step 2: Place the slurry, 25g zirconium powder, chromate, and 400ml deionized water in an electromagnetic water bath and stir to prepare a precursor mixture. The concentration of chromate is 1mol / L.

[0029] Step 3: Add concentrated hydrochloric acid to the precursor mixture to adjust the pH to 1, and then add barium chloride solution to the precursor mixture at a titration rate of 1 ml / s while maintaining stirring in a water bath for 10 min.

[0030] Step 4: Transfer the mixture in the water bath to the paper machine for forming. The forming thickness is 0.35mm. After drying the formed material at 60℃ for 18 hours, the thermal battery ignition material is obtained.

[0031] Example 2

[0032] Obtain thermal battery ignition material sample B by following these steps:

[0033] Step 1: Place 2g of asbestos loosening paper, 2g of glass fiber, and deionized water in a high-speed blender and blend for 10 minutes at 22000r / min to prepare a slurry with a concentration of 5g / L. Place barium chloride and 500ml of deionized water in a 60℃ electromagnetic water bath to prepare a barium chloride solution with a concentration of 1mol / L and transfer it to a burette.

[0034] Step 2: Place the slurry, 35g zirconium powder, chromate, and 200ml deionized water in an electromagnetic water bath and stir to prepare a precursor mixture. The concentration of chromate is 1mol / L.

[0035] Step 3: Add concentrated hydrochloric acid to the precursor mixture to adjust the pH to 1, and then add barium chloride solution to the precursor mixture at a titration rate of 2 ml / s while maintaining stirring in a water bath for 10 min.

[0036] Step 4: Transfer the mixture in the water bath to the paper machine for forming. The forming thickness is 0.4 mm. After drying the formed material at 75°C for 12 hours, the thermal battery ignition material is obtained.

[0037] Example 3

[0038] The following steps were taken to obtain thermal battery ignition material sample C:

[0039] Step 1: Place 2.0g of asbestos loosening paper, 1.5g of glass fiber, and deionized water in a high-speed blender and blend for 10 minutes at 22000r / min to prepare a slurry with a concentration of 5g / L. Place barium chloride and 500ml of deionized water in a 60℃ electromagnetic water bath to prepare a barium chloride solution with a concentration of 1mol / L and transfer it to a burette.

[0040] Step 2: Place the slurry, 30g zirconium powder, chromate, and 300ml deionized water in an electromagnetic water bath and stir to prepare a precursor mixture. The concentration of chromate is 1mol / L.

[0041] Step 3: Add concentrated hydrochloric acid to the precursor mixture to adjust the pH to 1, and then add barium chloride solution to the precursor mixture at a titration rate of 1.5 ml / s while maintaining stirring in a water bath for 10 min;

[0042] Step 4: Transfer the mixture in the water bath to the paper machine for forming. The forming thickness is 0.35mm. After drying the formed material at 70℃ for 15 hours, the thermal battery ignition material is obtained.

[0043] Example 4

[0044] The following steps were followed to obtain thermal battery ignition material sample D:

[0045] Step 1: Place 1.5g of asbestos loosening paper, 1.5g of glass fiber, and deionized water in a high-speed blender and blend for 10 minutes at 22000r / min to prepare a slurry with a concentration of 5g / L. Place barium chloride and 500ml of deionized water in a 60℃ electromagnetic water bath to prepare a barium chloride solution with a concentration of 1mol / L and transfer it to a burette.

[0046] Step 2: Place the slurry, 25g zirconium powder, chromate, and 400ml deionized water in an electromagnetic water bath and stir to prepare a precursor mixture. The concentration of chromate is 1mol / L.

[0047] Step 3: Add concentrated hydrochloric acid to the precursor mixture to adjust the pH to 1, and then add barium chloride solution to the precursor mixture at a titration rate of 1.5 ml / s while maintaining stirring in a water bath for 10 min;

[0048] Step 4: Transfer the mixture in the water bath to the paper machine for forming. The forming thickness is 0.35mm. After drying the formed material at 70℃ for 15 hours, the thermal battery ignition material is obtained.

[0049] Example 5

[0050] Obtain thermal battery ignition material sample E according to the following steps:

[0051] Step 1: Place 1.0g of asbestos loosening paper, 1.0g of glass fiber, and deionized water in a high-speed blender and blend for 10 minutes at 22000r / min to prepare a slurry with a concentration of 5g / L. Place barium chloride and 500ml of deionized water in a 60℃ electromagnetic water bath to prepare a barium chloride solution with a concentration of 1mol / L and transfer it to a burette.

[0052] Step 2: Place the slurry, 22g zirconium powder, chromate, and 600ml deionized water in an electromagnetic water bath and stir to prepare a precursor mixture. The concentration of chromate is 1mol / L.

[0053] Step 3: Add concentrated hydrochloric acid to the precursor mixture to adjust the pH to 1, and then add barium chloride solution to the precursor mixture at a titration rate of 2.0 ml / s while maintaining stirring in a water bath for 10 min.

[0054] Step 4: Transfer the mixture in the water bath to the paper machine for forming. The forming thickness is 0.30 mm. After drying the formed material at 65°C for 15 hours, the thermal battery ignition material is obtained.

[0055] The samples A to E of Examples 1 to 5 were tested: In Example 5, the linear burning rate of the ignition material sample was in the range of 200-250 cm / s, the uniformity of burning rate was improved by 50%, the ignition material was non-conductive before and after ignition and the combustion products had no aggregated particles, indicating that the conductive zirconium powder was completely coated; the material strength of the ignition material met the usage requirements during the assembly process, and the assembly qualification rate was 100%.

[0056] As can be seen from the above, the thermal battery ignition material prepared by the present invention has the characteristics of uniform combustion rate, good insulation and high structural strength.

[0057] It should be noted that the above description is merely illustrative and explanatory of the present invention. Those skilled in the art should understand that any modifications and substitutions to the present invention fall within the scope of protection of the present invention.

Claims

1. A thermal battery ignition material, characterized in that, include: The composition includes barium chromate, zirconium powder, asbestos loosening paper, and glass fiber. The barium chromate comprises 62%-75% by mass, the zirconium powder 22%-35% by mass, the asbestos loosening paper 1-2% by mass, and the glass fiber 1-2% by mass. The zirconium powder used contains more than 92% active zirconium, which is zero-valent metallic zirconium. The barium chromate is prepared by a precipitation reaction between barium chloride and a chromate solution. The thermal battery ignition material is prepared by a method including the following steps: Step 1: Place the asbestos loosened paper, glass fiber, and deionized water in a high-speed blender to crush and prepare a pulp. Place barium chloride and deionized water in a water bath to prepare a barium chloride solution. Step 2: Place the slurry, zirconium powder, chromate, and deionized water in a water bath and stir to prepare the precursor mixture; Step 3: Add concentrated hydrochloric acid to the precursor mixture to adjust the pH to 1, then titrate the barium chloride solution into the precursor mixture while maintaining stirring in a water bath; Step 4: Transfer the mixture in the water bath to the paper machine for forming. After drying the formed material, the thermal battery ignition material is obtained.

2. The thermal battery ignition material according to claim 1, characterized in that, In step one, the rotation speed for crushing and preparing the slurry is 22000 r / min, and the time is 10 min.

3. The thermal battery ignition material according to claim 2, characterized in that, In step one, the concentration of the slurry is 5 g / L, the water bath temperature is 60 ℃, and the concentration of the barium chloride solution is 1 mol / L.

4. The thermal battery ignition material according to claim 2, characterized in that, In step two, the concentration of chromate ions in the precursor mixture is 1 mol / L.

5. The thermal battery ignition material according to claim 2, characterized in that, In step three, the titration rate of the barium chloride solution is controlled at 1-2 ml / s, and after titration, the solution is stirred in a water bath for 10 minutes.

6. The thermal battery ignition material according to claim 2, characterized in that, In step four, the paper forming process involves removing moisture from the paper machine in one pass and then forming the paper.

7. The thermal battery ignition material according to claim 2, characterized in that, In step four, the drying temperature is 60℃-75℃, and the drying time is 12h-18h.

8. The thermal battery ignition material according to claim 6, characterized in that, In step four, the molding thickness of the ignition material is 0.3 mm to 0.4 mm.