Heating negative electrode integrated material for thermal battery, high-specific-energy single battery and preparation method of high-specific-energy single battery

Abstract

The invention relates to a heating negative electrode integrated material for a thermal battery, a high-specific-energy single battery and a preparation method of the high-specific-energy single battery, belonging to the technical field of thermal batteries. The formula of the heating negative electrode integrated material for the thermal battery comprises lithium, magnesium oxide and high-calorific-value metal / metalloid powder (selected from boron, aluminum, silicon, magnesium and iron); the lithium accounts for 30%-70% by weight, the magnesium oxide accounts for 0%-15% by weight, and the high-calorific-value metal / metalloid powder accounts for 25%-70% by weight. The heating negative electrode integrated material prepared by the invention has the dual functions of a negative electrode and a heating material in addition to exerting the advantages of the respective raw materials, and the weight of a single battery can be greatly reduced; good ion and electron conductivity is achieved, and the large-current discharge characteristic is good; no gas is generated in the combustion process, and the internal pressure of the thermal battery is prevented from being too high. Under the condition of the same volume and weight, the single battery prepared by the invention has longer working time.

Description

Technical Field

[0001] This invention belongs to the field of thermal battery technology, specifically relating to an integrated heating negative electrode material for thermal batteries, a high-energy-density single cell battery, and its preparation method. Background Technology

[0002] Thermal batteries, as a type of thermally activated backup battery that relies on its own heating system to heat and melt non-conductive solid salt electrolytes into ionic conductors and then enter the working state, have significant characteristics such as arbitrary angle activation, fast activation speed, long storage time, and strong ability to withstand environmental mechanical conditions. They have been widely used in various equipment fields, and their value in the civilian field is also gradually becoming apparent. Currently, there are research reports on their use as emergency power supplies for aircraft, fire alarm power supplies, and underground high-temperature mineral exploration power supplies.

[0003] With the continuous development and upgrading of equipment technology, the market and application scenarios have placed more stringent demands on the performance of thermal batteries. Specifically, the requirements for operating time are constantly increasing, the requirements for output power and high specific capacity are continuously rising, and the requirements for activation time are becoming increasingly stringent. From the perspective of the structural composition of thermal batteries, they mainly include a substrate, positive electrode, negative electrode, electrolyte sheet (or separator), sheet current collector, heating element, heat insulation pad, battery casing, and battery cover with terminals. Among these, the performance of thermal battery electrode materials has a decisive influence on key electrochemical performances such as battery output capacity, specific capacity, and specific power.

[0004] At the working principle level of thermal batteries, normal operation relies on heat to bring the electrolyte to a molten state. However, molten salt electrolytes currently used in engineering applications in China generally have high melting points. The higher the electrolyte melting point, the more heating material is required to meet the heating demands, directly leading to an increase in the overall battery size and weight. Statistics show that in traditional single-cell batteries, the heating source accounts for 1 / 4 to 1 / 3 of the total weight, and the negative electrode also accounts for 1 / 4 to 1 / 3. The independent placement of the heating and negative electrode components makes it difficult to optimize battery size and weight, becoming one of the key factors restricting the improvement of the specific energy of thermal batteries.

[0005] Meanwhile, ideal heating materials for thermal batteries need to meet multiple performance requirements: First, they need to provide a suitable calorific value range of 500–2500 J / g to ensure the electrolyte can fully melt; second, they need to have good electronic and ionic conductivity during operation to ensure stable high-current discharge characteristics; third, they must not produce gas during combustion to avoid excessive internal pressure causing safety hazards or performance failures; fourth, their thermal sensitivity needs to be moderate, allowing them to be successfully ignited by sparks from igniting paper while effectively resisting electrostatic interference to prevent accidental ignition. However, the independent heating and negative electrode materials in traditional thermal batteries cannot simultaneously meet these multi-dimensional performance requirements while maintaining a lightweight design, easily leading to performance imbalances and reduced operating time. Summary of the Invention

[0006] The present invention aims to provide an integrated heating and negative electrode material for thermal batteries, in order to solve the problem that it is difficult for separate heating and negative electrode materials to simultaneously meet the multi-dimensional performance requirements such as high calorific value, good conductivity, and no gas production during combustion while maintaining a lightweight design. This can easily lead to problems such as performance imbalance and reduced working time.

[0007] To achieve the above objectives, the first aspect of the present invention provides a formulation for an integrated heating negative electrode material for a thermal battery, characterized in that it comprises lithium, magnesium oxide, and high calorific value metal / metal-like powder, wherein the high calorific value metal / metal-like powder comprises one or more of boron, aluminum, silicon, magnesium, and iron; wherein the weight percentage of lithium is 30% to 70%, the weight percentage of magnesium oxide is 0% to 15%, and the weight percentage of the high calorific value metal / metal-like powder is 25% to 70%.

[0008] Furthermore, the magnesium oxide selected has an apparent specific volume greater than 20 mL·g. -1 Specific surface area greater than 60 m² 2 / g, with a particle size not greater than 100nm.

[0009] Furthermore, the lithium, boron, aluminum, silicon, magnesium, and iron are all powders with a particle size of 50 nm to 50 μm and a purity of >99.5%.

[0010] Furthermore, the high calorific value metal / metal-like powder is preferably a mixture of aluminum and iron in a weight ratio of 8:1, or a mixture of aluminum and silicon in a weight ratio of 8:1.

[0011] Secondly, the method for preparing an integrated heating negative electrode material for a thermal battery using the above-mentioned formulation includes the following steps: (1) First, put the high calorific value metal / metal-like powder and magnesium oxide into an inert drying oven or vacuum drying oven at a temperature of 40℃~200℃ to remove moisture for later use; (2) Weigh lithium, high calorific value metal / metal-like powder, and magnesium oxide and put them into a high-speed powder mixer and mix them evenly; (3) Finally, press the mixed powder into flakes according to the usage requirements.

[0012] Furthermore, the inert atmosphere is either argon or helium.

[0013] Furthermore, the entire preparation process is completed in a glove box, where the water and oxygen content is <1ppm.

[0014] Furthermore, it is prepared using the method of claim 5.

[0015] Furthermore, the high-energy-density single cell is mainly composed of a separator material, a positive electrode material, a current collector, and the integrated heating negative electrode material sheet as described in claim 6.

[0016] Furthermore, the high-energy-density single cell is prepared by stacking the integrated heating negative electrode material sheet, the separator material, the positive electrode sheet, and the current collector in that order. Beneficial technical effects of the present invention: 1. The integrated heating negative electrode material prepared by this invention not only leverages the advantages of its respective raw materials, but also has the dual functions of negative electrode and heating material, which can significantly reduce the weight of a single battery cell; it has good ionic and electronic conductivity and excellent high-current discharge characteristics; it does not produce gas during combustion, preventing excessive internal pressure of the thermal battery.

[0017] 2. Under the same volume and weight conditions, the single cell battery produced by this invention has a longer working time.

[0018] 3. The present invention has a simple preparation process, is easy to operate, has low equipment cost, and is conducive to large-scale production. In the traditional preparation process of single-cell batteries, the heating element and the positive electrode are pressed separately. By using an integrated heating and negative electrode material, the pressing process of the heating element can be reduced, the efficiency of thermal battery preparation can be improved, and labor costs can be reduced. Attached Figure Description

[0019] Figure 1 Calorific value test diagram of conventional heating materials and integrated heating negative electrode materials; Figure 2 : A schematic diagram of a conventional single-cell battery; Figure 3 : Schematic diagram of the high-energy-density single cell of the present invention. Detailed Implementation

[0020] The following detailed description illustrates the specific implementation method: Example 1: I. Preparation of integrated heating negative electrode material sheet for thermal batteries The entire process is carried out in a glove box with a water oxygen content of <1ppm, and includes the following steps: (1) First, put the mixed powder of Al and Si with a weight ratio of 8:1 and magnesium oxide into an inert drying oven at 180°C to remove moisture for later use; the inert gas is argon. (2) Weigh lithium, the mixed powder from step (1), and magnesium oxide in the following proportions of 50%, 45%, and 5% by weight, respectively, and mix them evenly in a high-speed mixer.

[0021] (3) Finally, the powder prepared in the second step is pressed into a disc of a certain diameter to obtain the integrated heating negative electrode material.

[0022] II. Preparation of High-Energy-Density Single-Cell Batteries like Figure 3 As shown, a high-energy-density single-cell battery is constructed by stacking a heated negative electrode integrated material sheet, a separator material, a positive electrode sheet, and a current collector. The positive electrode sheet weighs 7.2g, the separator sheet 2.8g, and the heated negative electrode integrated material sheet 7g, with a sheet diameter of 58mm.

[0023] Example 2: I. Preparation of integrated heating negative electrode material sheet for thermal batteries The entire process is carried out in a glove box with a water oxygen content of <1ppm, and includes the following steps: (1) First, put the mixed powder of Al and Fe with a weight ratio of 8:1 and magnesium oxide into an inert drying oven at 180°C to remove water for later use. (2) Weigh out lithium and the mixed powder from step (1) in the order of 45% and 55% by weight, respectively, and mix them evenly in a high-speed powder mixer; (Magnesium oxide can reduce the burning rate and prevent lithium overflow in large batteries. When the lithium content is relatively low, magnesium oxide can be omitted without affecting the effect).

[0024] (3) Finally, the powder prepared in the second step is pressed into a disc of a certain diameter to obtain the integrated heating negative electrode material.

[0025] II. Preparation of High-Energy-Density Single-Cell Batteries like Figure 3 As shown, a high-energy-density single-cell battery is constructed by stacking a heated negative electrode integrated material sheet, a separator material, a positive electrode sheet, and a current collector. The positive electrode sheet weighs 6.8g, the separator sheet 3.2g, and the heated negative electrode integrated material sheet 7g, with a sheet diameter of 58mm.

[0026] Comparative example: like Figure 2As shown, a conventional single-cell battery is assembled by stacking heating elements, current collectors, negative electrode sheets, separator sheets, positive electrode sheets, and substrates in that order. The positive electrode sheet weighs 6g, the separator sheet 2.8g, the negative electrode sheet 1.2g (a negative electrode sheet made of lithium-boron alloy, model LB20250727(304C), purchased from Hunan Ruilin New Energy Technology Co., Ltd.), and the heating element 7g (a conventional heating material composed of iron and potassium perchlorate), with a diameter of 58mm.

[0027] Test case The high-energy-density cells prepared in Example 1 and the comparative example were assembled into batteries, and their electrical performance was tested. Figure 1 It can be seen that for the same volume and weight of individual cells, high-energy-density cells assembled into batteries have a longer working time.

[0028] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions 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 implementation 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 formulation for an integrated heating negative electrode material for a thermal battery, characterized in that: It includes lithium, magnesium oxide, and high-calorific-value metal / metal-like powder, wherein the high-calorific-value metal / metal-like powder includes one or more of boron, aluminum, silicon, magnesium, and iron; the weight percentage of lithium is 30% to 70%, the weight percentage of magnesium oxide is 0% to 15%, and the weight percentage of high-calorific-value metal / metal-like powder is 25% to 70%.

2. The formulation of an integrated heating negative electrode material for a thermal battery according to claim 1, characterized in that: The magnesium oxide used is selected with an apparent volume greater than 20 mL·g. -1 Specific surface area greater than 60 m² 2 / g, with a particle size not greater than 100nm.

3. The formulation of an integrated heating negative electrode material for a thermal battery according to claim 1, characterized in that: The lithium, boron, aluminum, silicon, magnesium, and iron are all powders with a particle size of 50 nm to 50 μm and a purity of >99.5%.

4. The formulation of an integrated heating negative electrode material for a thermal battery according to claim 1, characterized in that: The high calorific value metal / metal-like powder is preferably a mixture of aluminum and iron in a weight ratio of 8:1, or a mixture of aluminum and silicon in a weight ratio of 8:

1.

5. A method for preparing an integrated heating negative electrode material for a thermal battery using the formulation of any one of claims 1 to 4, characterized in that: Includes the following steps: (1) First, put the high calorific value metal / metal-like powder and magnesium oxide into an inert drying oven or vacuum drying oven at a temperature of 40℃~200℃ to remove moisture for later use; (2) Weigh lithium, high calorific value metal / metalloid powder, and magnesium oxide and put them into a high-speed powder mixer and mix them evenly; (3) Finally, press the mixed powder into flakes according to the usage requirements.

6. The method according to claim 5, characterized in that: The inert atmosphere is either argon or helium.

7. The method according to claim 5, characterized in that: The entire preparation process is completed in a glove box, where the water and oxygen content is <1ppm.

8. An integrated heating negative electrode material sheet for a thermal battery, characterized in that: It was prepared using the method of claim 5.

9. A high-energy-density single cell for thermal batteries, characterized in that: The high-energy-density single cell is mainly composed of a separator material, a positive electrode material, a current collector, and the integrated heating negative electrode material sheet as described in claim 6.

10. A method for preparing a high-energy-density single cell for a thermal battery according to claim 7, characterized in that: The high-energy-density single cell is prepared by stacking the integrated heating negative electrode material sheet, the separator material, the positive electrode sheet, and the current collector in that order.

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