A diaphragm for long-duration end-pulse thermal battery and a preparation method thereof

Abstract

This invention belongs to the field of thermal battery technology, specifically relating to a separator for a long-endurance, high-pulse thermal battery and its preparation method. The separator material is a solid electrolyte-molten salt composite material, composed of an adsorbed solid electrolyte and a molten salt. This separator further extends the pulse loading time at the end of the thermal battery, meeting the safety requirements of thermal batteries, and is suitable for long-endurance, high-pulse, high-safety thermal batteries.

Description

Technical Field

[0001] This invention belongs to the field of thermal battery membrane material preparation technology, specifically relating to a membrane for a long-endurance, high-pulse thermal battery and its preparation method. Background Technology

[0002] A thermal battery is a thermally activated reserve battery. When stored at room temperature, the electrolyte is a non-conductive solid. During use, an electric ignition head or firing pin mechanism ignites the internal heating agent, melting the electrolyte and turning it into an ionic conductor, thus activating the reserve battery. Theoretically, its storage time is unlimited, with practically measurable values ​​exceeding 17 years. Due to its high output power, low internal resistance, wide operating temperature range, long storage time, rapid and reliable activation, and maintenance-free operation, it has been developed into an ideal power source for modern weapons.

[0003] With the rapid development of the defense industry, increasingly higher power requirements are being placed on thermal batteries. In addition to long-term output, thermal batteries are also required to provide short-term large-pulse discharge at the end of the period. However, the thermal batteries currently in use are difficult to achieve large-pulse discharge at the end of the period due to factors such as the pyrolysis of the positive electrode material, heat loss, and increased internal resistance due to the solidification of the internal molten salt. Even if they can achieve this, the operating voltage drops sharply due to the increased internal polarization resistance, which cannot meet the operating voltage requirements of the electrical equipment. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a separator for a long-endurance, high-pulse thermal battery and its preparation method.

[0005] Specifically, this is achieved through the following technical solutions:

[0006] The membrane material is a solid electrolyte-molten salt composite material, composed of an adsorbent solid electrolyte and a molten salt. The preparation method includes the following steps:

[0007] Step 1: Preparation method of adsorbent solid electrolyte precursor: Dissolve the adsorbent precursor powder in an alcohol solvent to form an adsorbent precursor liquid of a certain concentration, then heat it to 50°C and stir for 1 hour to form a precursor liquid, then invert the solid electrolyte into the precursor liquid in a certain proportion to obtain the adsorbent solid electrolyte precursor for later use.

[0008] Step 2: Preparation method of adsorbent solid electrolyte: The adsorbent solid electrolyte precursor prepared in Step 1 is placed in a mechanically stirred and heated vessel. Under mechanical stirring, the temperature is increased to a certain temperature at 5℃ / min, and then kept at this temperature for a period of time before being cooled naturally to obtain adsorbent solid electrolyte particles.

[0009] Step 3: Preparation method of adsorbent solid electrolyte powder: The adsorbent solid electrolyte particles prepared in step 2 are placed in a pulverizer, pulverized, sieved, and ball-milled to obtain adsorbent solid electrolyte powder.

[0010] Step 4: Preparation method of solid electrolyte-molten salt composite material: The adsorbent solid electrolyte powder and molten salt prepared in step 3 are mixed at a mass ratio of 1:1 and placed in a planetary mixer. After mixing for 5 minutes, the mixture is sieved to obtain the final product.

[0011] The precursor powder of the adsorbent material in step 1 is at least one of magnesium nitrate, magnesium acetate, and aluminum acetate.

[0012] The alcohol agent mentioned in step 1 is one or a mixture of two of methanol, ethanol, propanol, and butanol.

[0013] The concentration of the precursor liquid for the adsorption material in step 1 is 0.5 mol / L to 2 mol / L; the mixing ratio of the solid electrolyte and the precursor liquid is 100 g / L to 500 g / L.

[0014] The heating temperature in step 2 is 450℃~800℃, and the holding time is 0.5h~4h;

[0015] The sieving process in step 3 is 40 mesh to 300 mesh;

[0016] The molten salt in step 4 is one of a system of molten salt of nitrate compound and molten salt of halide compound;

[0017] The sieving in step 4 is a 40-300 mesh sieve;

[0018] The solid electrolyte is an oxide and sulfide solid electrolyte.

[0019] Beneficial effects:

[0020] The long-endurance end-pulse thermal battery prepared by this invention uses an inorganic solid electrolyte with adsorption properties as a framework to stabilize the molten salt of the thermal battery. In the later stage of thermal battery operation, after the internal temperature drops rapidly, the conductivity of the molten salt will drop rapidly. The solid electrolyte wetted by the molten salt has good conductivity, which can enhance the end-pulse of the thermal battery. It is suitable for high-safety, long-endurance end-pulse thermal batteries. Attached Figure Description

[0021] Figure 1 The discharge curve of the diaphragm using the patent in this application.

[0022] Figure 2 The discharge curves are for conventional thermal battery separators. Detailed Implementation

[0023] The specific embodiments of the present invention will be described in further detail below, but the present invention is not limited to these embodiments. Any improvements or substitutions based on the basic spirit of these embodiments shall still fall within the scope of protection claimed by the claims of the present invention.

[0024] Example 1

[0025] According to the preparation method of the thermal battery membrane for large-pulse batteries at the end, magnesium acetate powder is first dissolved in a mixed solvent of methanol and isopropanol to form a 1 mol / L concentration of adsorbent precursor liquid. After heating to 50°C and stirring for 1 hour, the precursor liquid is formed. LLZTO oxide solid electrolyte is then added to the precursor liquid at a ratio of 100 g / L to obtain LLZTO adsorbent solid electrolyte precursor for later use. The prepared LLZTO precursor is placed in a mechanically stirred and heated vessel. Under mechanical stirring and atmospheric atmosphere, the temperature is increased to 550°C at a rate of 5°C / min and held at this temperature for 1 hour, followed by natural cooling to obtain adsorbent solid electrolyte particles. The prepared adsorbent solid electrolyte particles are then pulverized in a pulverizer, passed through a 100-mesh sieve, and ball-milled to obtain adsorbent solid electrolyte powder. The prepared adsorbent solid electrolyte powder and LiF-LiCl-LiBr are then mixed in a 1:1 ratio and placed in a planetary mixer. After mixing for 5 minutes, the mixture is passed through an 80-mesh sieve to obtain the final product.

[0026] Example 2

[0027] According to the preparation method of the thermal battery membrane for large-pulse batteries at the end, aluminum acetate powder is first dissolved in propanol to form a 1 mol / L concentration of adsorbent precursor liquid. After heating to 50°C and stirring for 1 h, a perovskite solid electrolyte is added to the precursor liquid at a ratio of 150 g / L to obtain a perovskite solid electrolyte precursor for later use. The prepared precursor is placed in a mechanically stirred and heated vessel, and under mechanical stirring and atmospheric atmosphere, the temperature is increased to 600°C at a rate of 5°C / min and held at this temperature for 1.5 h before natural cooling to obtain adsorbent solid electrolyte particles. The prepared adsorbent solid electrolyte particles are pulverized in a pulverizer, passed through a 100-mesh sieve, and ball-milled to obtain adsorbent solid electrolyte powder. The prepared adsorbent solid electrolyte powder and LiF-NaF-KF molten salt are then mixed in a 1:1 ratio and placed in a planetary mixer. After mixing for 5 min, the mixture is passed through an 80-mesh sieve to obtain the final product.

[0028] Example 3

[0029] According to the preparation method of the thermal battery membrane for large-pulse batteries at the end, magnesium nitrate powder is first dissolved in a mixed solvent of methanol and isopropanol to form a 1 mol / L concentration of adsorbent precursor liquid. After heating to 50°C and stirring for 1 hour, the precursor liquid is formed. LLZTO oxide solid electrolyte is then added to the precursor liquid at a ratio of 100 g / L to obtain LLZTO adsorbent solid electrolyte precursor for later use. The prepared LLZTO precursor is placed in a mechanically stirred and heated vessel. Under mechanical stirring and atmospheric atmosphere, the temperature is increased to 550°C at a rate of 5°C / min and held at this temperature for 1 hour, followed by natural cooling to obtain adsorbent solid electrolyte particles. The prepared adsorbent solid electrolyte particles are then pulverized in a pulverizer, passed through a 100-mesh sieve, and ball-milled to obtain adsorbent solid electrolyte powder. The prepared adsorbent solid electrolyte powder and LiNO3-NaNO3-KNO3 are then mixed in a 1:1 ratio and placed in a planetary mixer. After mixing for 5 minutes, the mixture is passed through an 80-mesh sieve to obtain the final product.

[0030] Performance Comparison: Using FeS2 as the positive electrode, LiB as the negative electrode, and a mixture of Fe powder and KClO4 as the heating powder, the product prepared in Example 1 was used as the separator. These were assembled into individual thermal battery cells, and then 18 cells were connected in series to form a thermal battery unit. Electrical performance was then tested. A separator made from a conventional 1:1 mixture of LiF-LiCl-LiBr and MgO was used as a control separator. Discharge curves are shown below. Figure 1 and Figure 2 As shown in the figure, the diaphragm of this application has the advantage of good end-pulse load-carrying capacity, making it suitable for long-endurance end-pulse thermal batteries.

Claims

1. A method for preparing a separator for a long-endurance, high-pulse thermal battery, characterized in that, The membrane material is a solid electrolyte-molten salt composite material, which is composed of an adsorbent solid electrolyte and a molten salt. The specific preparation method includes the following steps: Step 1: Preparation method of adsorbent solid electrolyte precursor: Dissolve the adsorbent material precursor powder in an alcohol solvent to form an adsorbent material precursor liquid, then heat it to 50°C and stir it evenly for 1 hour to form a precursor liquid. Then, invert the solid electrolyte into the precursor liquid to obtain the adsorbent solid electrolyte precursor for later use. Step 2: Preparation method of adsorbent solid electrolyte: The adsorbent solid electrolyte precursor prepared in Step 1 is placed in a mechanically stirred heating vessel and heated under atmospheric stirring at a heating rate of 5℃ / min to 450℃~800℃. After holding at this temperature for 0.5h~4h, it is cooled naturally to obtain adsorbent solid electrolyte particles. Step 3: Preparation method of adsorbent solid electrolyte powder: The adsorbent solid electrolyte particles prepared in step 2 are placed in a pulverizer, pulverized, sieved, and ball-milled to obtain adsorbent solid electrolyte powder. Step 4: Preparation method of solid electrolyte-molten salt composite material: The adsorbent solid electrolyte powder and molten salt prepared in step 3 are mixed at a mass ratio of 1:1 and placed in a planetary mixer. After mixing for 5 minutes, the mixture is sieved to obtain the final product. The solid electrolyte is an oxide solid electrolyte and a sulfide solid electrolyte; The molten salt is one of the molten salt systems of nitrate compounds and halogen compounds.

2. The method for preparing a separator for a long-endurance, high-pulse thermal battery as described in claim 1, characterized in that, The precursor powder of the adsorbent material in step 1 is at least one of magnesium nitrate, magnesium acetate, and aluminum acetate.

3. The method for preparing a separator for a long-endurance, high-pulse thermal battery as described in claim 1, characterized in that, The alcohol solvent in step 1 is one or a mixture of two of methanol, ethanol, propanol, butanol, and isopropanol.

4. The method for preparing a separator for a long-endurance, high-pulse thermal battery as described in claim 1, characterized in that, The concentration of the precursor liquid for the adsorption material in step 1 is 0.5 mol / L to 2 mol / L; the mixing ratio of the solid electrolyte and the precursor liquid is 100 g / L to 500 g / L.

5. The method for preparing a separator for a long-endurance, high-pulse thermal battery as described in claim 1, characterized in that, The sieving process in step 3 is 40 mesh to 300 mesh.

6. The method for preparing a separator for a long-endurance terminal high-pulse thermal battery as described in claim 1, characterized in that, The sieving in step 4 is a 40-300 mesh sieve.

7. A separator for a long-endurance terminal large pulse thermal battery prepared by the preparation method described in claim 1.

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