A method for preparing electrolyte for a thermal battery in an automatic press

Abstract

A method for preparing electrolyte for an automatic press thermal battery belongs to the field of thermal battery technology. The method involves: mixing magnesium oxide and molten salt and calcining the mixture; pulverizing the resulting electrolyte block into a semi-finished electrolyte product using an airflow mill; thoroughly mixing the semi-finished electrolyte product, subjecting it to vacuum treatment, and removing it after reaching a certain vacuum level; subjecting the semi-finished product to a second calcination, followed by airflow milling to obtain the finished electrolyte product. By performing a second homogenization treatment on the electrolyte powder, the prepared electrolyte powder exhibits high particle size concentration and good flowability, making it suitable for pressing ultra-large and ultra-thin electrolyte sheets in an automatic press. This improves the specific energy and specific power of the thermal battery, broadening its application scenarios.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of thermal batteries, and particularly relates to a preparation method of a thermal battery electrolyte for an automatic pressing machine. BACKGROUND

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

[0003] With the development of technology, the production of thermal batteries has developed from manual scraping to single-layer sheet pressing by an automatic pressing machine. The physical property requirements of the electrolyte powder have changed greatly. In addition, with the upgrading of thermal battery products, the demand for high specific energy and high power is increasing, and the electrolyte layer of the thermal battery is required to be larger and thinner. These all put forward higher requirements for the preparation of the electrolyte powder of the thermal battery, and the process needs to be improved urgently.

[0004] The thermal battery electrolyte is a mixture of an adsorbent carrier and molten salt after high-temperature calcination and cooling. The particle consistency is poor, that is, some powder particles have high molten salt content, and some powder particles have low molten salt content. This will cause the particle size distribution of the finished product to be unable to concentrate when the powders with different hardnesses are crushed, and the flowability is poor, which is difficult to meet the high requirements of the automatic pressing machine on the consistency of the powder. SUMMARY

[0005] The purpose of the present application is to solve the problem that the molten salt particles of the thermal battery electrolyte have different compositions and poor flowability, which leads to the problem that the electrolyte cannot be used for pressing the ultra-large and ultra-thin electrolyte sheet by the automatic pressing machine. The present application provides a preparation method of a thermal battery electrolyte for an automatic pressing machine. The method can greatly reduce the problem of different particle compositions by performing secondary homogenization treatment on the electrolyte powder, so that the particle size concentration of the electrolyte is obviously improved after airflow crushing.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] A preparation method of a thermal battery electrolyte for an automatic pressing machine, the method comprises the following steps:

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

[0009] (2) airflow crushing the electrolyte block obtained in step (1) into an electrolyte semi-finished product;

[0010] (3) The electrolyte semi-product is fully stirred and mixed, placed in a crucible, and then placed in a vacuum oven for vacuumizing treatment, and taken out after being vacuumized to a certain degree, which is to remove air and increase the contact between powders;

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

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

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

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

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

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

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

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

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

[0020] The present application has the following beneficial effects over the prior art: the present application subjects the electrolyte powder to secondary homogenization treatment, so that the prepared electrolyte powder has high particle size concentration and good flowability, is suitable for the pressing of super-large and super-thin electrolyte sheets by an automatic press, improves the specific energy and specific power of a thermal battery, and widens the use scenarios of the thermal battery. BRIEF DESCRIPTION OF DRAWINGS

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

[0022] Figure 2 is an electron microscope photo of the electrolyte product of Example 3;

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

[0024] Figure 4 Figure 3 is a particle size distribution graph of the electrolyte product of Example 3. DETAILED DESCRIPTION

[0025] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to examples. It should be understood that the specific examples described herein are only used to explain the present application and not intended to limit the present application.

[0026] Example 1

[0027] A preparation method of a hot battery electrolyte for an automatic press, comprising:

[0028] (1) magnesium oxide and LiF-LiCl-LiBr are mixed at a ratio of 1:1 and placed in a crucible, which is then placed in a muffle furnace, and a first calcination is performed at 550°C at a heating rate of 10°C / min, and after 5h of heat preservation, the electrolyte is poured into an iron plate;

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

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

[0031] (4) the above-mentioned crucible is placed in a muffle furnace, a second calcination is performed at 500°C at a heating rate of 10°C / min, and after 3h of heat preservation, the electrolyte is poured into an iron plate, and then air-flow pulverized to obtain an electrolyte product with a particle size D50 of 55μm.

[0032] (5) the above-mentioned powder is pressed into a single layer sheet by an automatic press, the single layer sheet has a diameter of 50mm, the powder amount is 2±0.04g, the pressing pressure is 80T, 1000 sheets are pressed, and the calculated product yield is 92%.

[0033] Example 2

[0034] A preparation method of a hot battery electrolyte for an automatic press, comprising:

[0035] (1) magnesium oxide and LiCl-KCl are mixed at a ratio of 1:1 and placed in a crucible, which is then placed in a muffle furnace, and a first calcination is performed at 580°C at a heating rate of 10°C / min, and after 8h of heat preservation, the electrolyte is poured into an iron plate;

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

[0037] (3) The electrolyte powder semi-product is fully stirred and mixed, placed in a crucible, and then put into a vacuum oven for vacuum exhaust treatment. After being extracted to 100 Pa, it is taken out;

[0038] (4) The above-mentioned crucible is placed in a muffle furnace, the temperature rising rate is 10°C / min, secondary calcination is carried out at 480°C, and after 3h of heat preservation, it is poured into an iron plate, and then air flow crushing is carried out, to obtain an electrolyte finished product with a particle size D50 of 45 μm.

[0039] (5) The above-mentioned powder is subjected to automatic press single-layer sheet pressing, the single-layer sheet diameter is 50 mm, the powder amount is 2±0.04 g, the pressing pressure is 80T, 1000 sheets are pressed, and the calculated finished product rate is 94%.

[0040] Example 3:

[0041] A preparation method of a hot battery electrolyte for an automatic press, comprising:

[0042] (1) Magnesium oxide and LiCl-LiBr-KBr mixed at 1:1 are placed in a crucible, and placed in a muffle furnace, the temperature rising rate is 10°C / min, and the first calcination is carried out at 500°C, and after 8h of heat preservation, it is poured into an iron plate;

[0043] (2) The electrolyte block is air flow crushed into an electrolyte semi-product with a particle size D50 of 35 μm, Figure 1 and Figure 3 respectively, an electron microscope photo and a particle size distribution diagram of the semi-product;

[0044] (3) The electrolyte powder semi-product is fully stirred and mixed, placed in a crucible, and then put into a vacuum oven for vacuum exhaust treatment. After being extracted to 500 Pa, it is taken out;

[0045] (4) The above-mentioned crucible is placed in a muffle furnace, the temperature rising rate is 10°C / min, secondary calcination is carried out at 450°C, and after 2h of heat preservation, it is poured into an iron plate, and then air flow crushing is carried out, to obtain an electrolyte finished product with a particle size D50 of 50 μm, Figure 2 and Figure 4 respectively, an electron microscope photo and a particle size distribution diagram of the finished product.

[0046] (5) The above-mentioned powder is subjected to automatic press single-layer sheet pressing, the single-layer sheet diameter is 50 mm, the powder amount is 2±0.04 g, the pressing pressure is 80T, 1000 sheets are pressed, and the calculated finished product rate is 98%.

[0047] Example 4:

[0048] A preparation method of a hot battery electrolyte for an automatic press, comprising:

[0049] (1) Put the mixture of magnesium oxide and LiCl-LiBr-KBr in a ratio of 4:6 into a crucible, and place it in a muffle furnace, with a heating rate of 10°C / min, and perform the first calcination at 520°C, and after holding for 4h, pour it into an iron plate;

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

[0051] (3) Mix the electrolyte powder semi-product thoroughly, place it in a crucible, and then put it into a vacuum oven for vacuum exhaust treatment, and after exhausting to 200Pa, take it out;

[0052] (4) Put the above-mentioned crucible into a muffle furnace, with a heating rate of 10°C / min, and perform the second calcination at 480°C, and after holding for 3h, pour it into an iron plate, and then perform airflow crushing to obtain an electrolyte product with a particle size D50 of 45μm.

[0053] (5) Perform automatic press single-layer sheet pressing on the above-mentioned powder, with a single-layer sheet diameter of 50mm, a powder amount of 2±0.04g, a pressing pressure of 80T, and press 1000 sheets, and the calculated product yield is 95%.

[0054] The above has described in detail the multiple embodiments of the present application, but the content described is only the preferred embodiments of the present application, and cannot be considered as used to limit the implementation scope of the present application. Any equivalent changes and improvements made according to the scope of the present application should still belong to the patent coverage scope of the present application.

Claims

1. A process for the preparation of a hot cell electrolyte for an automatic press, characterized in that: The method is: (1) mix magnesium oxide and molten salt, and perform calcination; (2) airflow crush the electrolyte block obtained in (1) into electrolyte semi-product; (3) fully stir and mix the electrolyte semi-product, perform vacuum extraction treatment, and take out after extraction to a certain vacuum degree; the vacuum degree ranges from 100 Pa to 1000 Pa; (4) perform secondary calcination on the semi-product obtained in (3), and then perform airflow crushing to obtain electrolyte product.

2. A method of preparing a hot cell 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. A method of preparing a hot cell electrolyte for an automatic press according to claim 1, characterized in that: In step (1), the mass percentage of the magnesium oxide ranges from 40% to 60%.

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

5. A method of preparing a hot cell electrolyte for an automatic press according to claim 1, characterized in that: In step (1), the calcination temperature ranges from 500 ℃ to 600 ℃, the temperature rising rate is 10 ℃ / min, and the holding time ranges from 2 h to 8 h.

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

7. A method of preparing a hot cell electrolyte for an automatic press according to claim 1, characterized in that: In step (4), the secondary calcination temperature ranges from 450 ℃ to 550 ℃, the temperature rising rate is 10 ℃ / min, and the holding time ranges from 2 h to 8 h.

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

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