Preparation method of thermal battery electrolyte for automatic press

Abstract

The invention discloses a preparation method of a thermal battery electrolyte for an automatic press and belongs to the technical field of thermal batteries. The method comprises the following steps: mixing magnesium oxide and fused salt, and calcining; the obtained electrolyte block is subjected to airflow crushing to form an electrolyte semi-finished product; fully stirring and mixing the electrolyte semi-finished product, performing vacuumizing treatment, and taking out the electrolyte semi-finished product after the electrolyte semi-finished product is vacuumized to a certain vacuum degree; and carrying out secondary calcination on the obtained semi-finished product, and then carrying out airflow pulverization to obtain an electrolyte finished product. Through secondary homogenization treatment on the electrolyte powder, the prepared electrolyte powder is high in particle size concentration ratio and good in fluidity, and is suitable for pressing an oversized and ultrathin electrolyte sheet by an automatic press, so that the specific energy and the specific power of the thermal battery are improved, and the use scene of the thermal battery is widened.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal batteries, and in particular relates to a method for preparing a thermal battery electrolyte for an automatic press. Background Art

[0002] A thermal battery is an energy storage device that uses its own heating system to heat and melt non-conductive molten salt into an ionic conductor to enter a working state. Its operating temperature is usually between 135 and 600°C. It has the advantages of short activation time, long storage life, high safety performance, wide operating temperature range, compact structure, and no maintenance required. It is an ideal power source for modern weapons and occupies a very important position in military power sources.

[0003] With the development of technology, the production of thermal batteries has developed from manual scraping to single-layer sheet pressing by automatic presses, which has brought about significant changes in the physical properties requirements of the electrolyte powder. In addition, with the upgrading of thermal battery products, the demand for high specific energy and high power is increasing, requiring the electrolyte layer of thermal batteries to develop towards larger and thinner. All these have put forward higher requirements for the preparation of thermal battery electrolyte powder, and there is an urgent need for process improvement.

[0004] Thermal battery electrolyte is a mixture of adsorption carrier and molten salt after high-temperature calcination and cooling. Its particle consistency is poor, that is, some powder particles have high molten salt content, while some powder particles have low molten salt content. This will cause the finished product particle size distribution to be unable to be concentrated when these powders of different hardness are crushed, and the fluidity is poor, making it difficult to meet the high requirements of the automatic press for powder consistency. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the molten salt particles of thermal battery electrolyte have different compositions and poor fluidity, which makes them unsuitable for pressing ultra-large and ultra-thin electrolyte sheets on automatic presses. A method for preparing thermal battery electrolyte for automatic presses is provided. The method can reduce the problem of different particle compositions to a large extent by performing secondary homogenization treatment on the electrolyte powder, so that the concentration of electrolyte particle size is significantly improved after air flow crushing.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a hot battery electrolyte for an automatic press, the method comprising:

[0008] (1) Mixing magnesium oxide and molten salt, placing them in a crucible for calcining, and pouring them into an iron plate after calcination;

[0009] (2) air-grinding the electrolyte block obtained in (1) into an electrolyte semi-finished product;

[0010] (3) The semi-finished electrolyte product is fully stirred and mixed, placed in a crucible, and then placed in a vacuum oven for vacuum treatment. After a certain vacuum degree is reached, it is taken out. This step is to exclude air and increase the contact between powders;

[0011] (4) The semi-finished product obtained in (3) is subjected to secondary calcination, poured into an iron plate after calcination, and then subjected to air flow pulverization to obtain a finished electrolyte product.

[0012] Furthermore, in step (1), the molten salt is one of LiF-LiCl-LiBr, LiCl-KCl or LiCl-LiBr-KBr.

[0013] Furthermore, in step (1), the mass percentage of the magnesium oxide is 40% to 60%.

[0014] Furthermore, in step (1), the calcining furnace is a muffle furnace or a pit furnace.

[0015] Furthermore, in step (1), the calcination temperature is 500-600° C., the heating rate is 10° C. / min, and the holding time is 2-8 h.

[0016] Furthermore, in step (2), the particle size D50 of the electrolyte semi-finished product ranges from 20 to 40 μm.

[0017] Furthermore, in step (3), the vacuum degree ranges from 100 to 1000 Pa.

[0018] Furthermore, in step (4), the temperature of the secondary calcination is 450-550° C., the heating rate is 10° C. / min, and the holding time is 2-8 h.

[0019] Furthermore, in step (4), the particle size D50 of the finished electrolyte product ranges from 40 to 60 μm.

[0020] The beneficial effects of the present invention compared to the prior art are as follows: the present invention performs secondary homogenization treatment on the electrolyte powder, so that the prepared electrolyte powder has high particle size concentration and good fluidity, is suitable for pressing ultra-large and ultra-thin electrolyte sheets on an automatic press, improves the specific energy and specific power of the thermal battery, and broadens the application scenarios of the thermal battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is an electron microscope photograph of the semi-finished electrolyte of Example 3;

[0022] Figure 2 is an electron microscope photograph of the finished electrolyte of Example 3;

[0023] Figure 3 is a particle size distribution diagram of the semi-finished electrolyte of Example 3;

[0024] Figure 4 This is the particle size distribution diagram of the finished electrolyte of Example 3. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] Embodiment 1:

[0027] A method for preparing a thermal battery electrolyte for an automatic press, comprising:

[0028] (1) Magnesium oxide and LiF-LiCl-LiBr were mixed in a ratio of 1:1 and placed in a crucible, which was placed in a muffle furnace. The mixture was heated at a rate of 10°C / min and calcined at 550°C for the first time. After keeping the mixture for 5 hours, the mixture was poured into an iron plate.

[0029] (2) air-grinding the electrolyte block into an electrolyte semi-finished product with a particle size D50 of 30 μm;

[0030] (3) The semi-finished electrolyte powder is fully stirred and mixed, placed in a crucible, and then placed in a vacuum oven for vacuum exhaust treatment, and taken out after being evacuated to 500 Pa;

[0031] (4) The crucible was placed in a muffle furnace, heated at a rate of 10°C / min, and calcined twice at 500°C. After keeping the temperature for 3 hours, the crucible was poured into an iron plate, and then air flow crushed to obtain an electrolyte product with a particle size D50 of 55 μm.

[0032] (5) The above powder was pressed into a single-layer tablet using an automatic press. The diameter of the single-layer tablet was 50 mm, the powder amount was 2±0.04 g, the pressing pressure was 80 T, 1000 tablets were pressed, and the calculated yield was 92%.

[0033] Embodiment 2:

[0034] A method for preparing a thermal battery electrolyte for an automatic press, comprising:

[0035] (1) Mixing magnesium oxide and LiCl-KCl in a ratio of 1:1 in a crucible, placing the mixture in a muffle furnace, heating the mixture at a rate of 10°C / min, calcining the mixture at 580°C for the first time, and keeping the mixture at that temperature for 8 hours before pouring the mixture into an iron plate;

[0036] (2) air-grinding the electrolyte block into an electrolyte semi-finished product with a particle size D50 of 20 μm;

[0037] (3) The semi-finished electrolyte powder is fully stirred and mixed, placed in a crucible, and then placed in a vacuum oven for vacuum exhaust treatment, and taken out after being evacuated to 100 Pa;

[0038] (4) The crucible was placed in a muffle furnace, heated at a rate of 10°C / min, and calcined twice at 480°C. After keeping the temperature for 3 hours, the crucible was poured into an iron plate, and then air flow crushed to obtain an electrolyte product with a particle size D50 of 45 μm.

[0039] (5) The above powder was pressed into a single-layer tablet using an automatic press. The diameter of the single-layer tablet was 50 mm, the powder amount was 2±0.04 g, the pressing pressure was 80 T, and 1000 tablets were pressed. The calculated yield was 94%.

[0040] Embodiment 3:

[0041] A method for preparing a thermal battery electrolyte for an automatic press, comprising:

[0042] (1) Magnesium oxide and LiCl-LiBr-KBr were mixed in a ratio of 1:1 and placed in a crucible, which was placed in a muffle furnace. The temperature was increased at a rate of 10°C / min and the first calcination was performed at 500°C. After keeping the temperature for 8 hours, the mixture was poured into an iron plate.

[0043] (2) Grinding the electrolyte block into a semi-finished electrolyte product with a particle size D50 of 35 μm; Figure 1 and Figure 3 They are respectively the electron microscope photo and particle size distribution diagram of the semi-finished product;

[0044] (3) The semi-finished electrolyte powder is fully stirred and mixed, placed in a crucible, and then placed in a vacuum oven for vacuum exhaust treatment, and taken out after being evacuated to 500 Pa;

[0045] (4) placing the crucible in a muffle furnace, heating at a rate of 10°C / min, performing secondary calcination at 450°C, keeping the temperature for 2 hours, pouring the crucible into an iron plate, and then performing air flow crushing to obtain an electrolyte product with a particle size D50 of 50 μm. Figure 2 and Figure 4 They are respectively the electron microscope photo and particle size distribution diagram of the finished product.

[0046] (5) The above powder was pressed into a single-layer tablet using an automatic press. The diameter of the single-layer tablet was 50 mm, the powder amount was 2±0.04 g, the pressing pressure was 80 T, 1000 tablets were pressed, and the calculated yield was 98%.

[0047] Embodiment 4:

[0048] A method for preparing a thermal battery electrolyte for an automatic press, comprising:

[0049] (1) Magnesium oxide and LiCl-LiBr-KBr were mixed in a ratio of 4:6 and placed in a crucible, which was placed in a muffle furnace. The temperature was increased at a rate of 10°C / min and the first calcination was performed at 520°C. After keeping the mixture at this temperature for 4 hours, the mixture was poured into an iron plate.

[0050] (2) air-grinding the electrolyte block into an electrolyte semi-finished product with a particle size D50 of 25 μm;

[0051] (3) The semi-finished electrolyte powder is fully stirred and mixed, placed in a crucible, and then placed in a vacuum oven for vacuum exhaust treatment, and taken out after being evacuated to 200 Pa;

[0052] (4) The crucible was placed in a muffle furnace, heated at a rate of 10°C / min, and calcined twice at 480°C. After keeping the temperature for 3 hours, the crucible was poured into an iron plate, and then air flow crushed to obtain an electrolyte product with a particle size D50 of 45 μm.

[0053] (5) The above powder was pressed into a single-layer tablet using an automatic press. The diameter of the single-layer tablet was 50 mm, the powder amount was 2±0.04 g, the pressing pressure was 80 T, 1000 tablets were pressed, and the calculated yield was 95%.

[0054] The above describes in detail the multiple embodiments of the present invention, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for preparing a thermal battery electrolyte for an automatic press, characterized in that: The method is: (1) mixing magnesium oxide and molten salt and calcining; (2) air-grinding the electrolyte block obtained in (1) into an electrolyte semi-finished product; (3) the semi-finished electrolyte product is fully stirred and mixed, and vacuumed to a certain vacuum degree before being taken out; (4) The semi-finished product obtained in (3) is subjected to secondary calcination and then subjected to air flow pulverization to obtain a finished electrolyte product.

2. The method for preparing a hot battery electrolyte for an automatic press according to claim 1, characterized in that: In step (1), the molten salt is one of LiF-LiCl-LiBr, LiCl-KCl or LiCl-LiBr-KBr.

3. The method for preparing a thermal battery electrolyte for an automatic press according to claim 1, characterized in that: In step (1), the mass percentage of magnesium oxide is 40% to 60%.

4. The method for preparing a hot battery electrolyte for an automatic press according to claim 1, characterized in that: In step (1), the calcining furnace is a muffle furnace or a pit furnace.

5. The method for preparing a hot battery electrolyte for an automatic press according to claim 1, characterized in that: In step (1), the calcination temperature is 500-600°C, the heating rate is 10°C / min, and the holding time is 2-8h.

6. The method for preparing a hot battery electrolyte for an automatic press according to claim 1, characterized in that: In step (2), the particle size D50 of the electrolyte semi-finished product ranges from 20 to 40 μm.

7. The method for preparing a hot battery electrolyte for an automatic press according to claim 1, characterized in that: In step (3), the vacuum degree ranges from 100 to 1000 Pa.

8. The method for preparing a hot battery electrolyte for an automatic press according to claim 1, characterized in that: In step (4), the temperature of the secondary calcination is 450-550° C., the heating rate is 10° C. / min, and the holding time is 2-8 h.

9. The method for preparing a hot battery electrolyte for an automatic press according to claim 1, characterized in that: In step (4), the particle size D50 of the finished electrolyte product ranges from 40 to 60 μm.

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