Preparation method of thermal activated battery with silicon-aluminum alloy high temperature phase change material

Abstract

The present application relates to the technical field of battery thermal management, in particular to a preparation method of a thermal activation battery with silicon-aluminum alloy high-temperature phase change material; in the preparation method, a certain amount of aluminum powder and silicon powder are selected as raw materials and mixed to obtain a liquid alloy by heating, the liquid alloy is defoamed and degranulated, and finally the bulk alloy is cooled to obtain a block alloy, the block alloy is sliced according to the size to obtain a sheet material, and the sheet material is assembled into the battery body in a layer insertion manner; the alloy phase change material prepared by the present scheme has high thermal conductivity, suitable phase change temperature and phase change enthalpy value, thereby having strong thermal management efficiency, being beneficial to regulating and controlling the surface temperature of the battery and prolonging the service life of the battery; in the present scheme, the alloy phase change material is cut and assembled into the thermal activation battery, and has the advantages of low cost, simple operation, good use effect and the like.

Description

Technical Field

[0001] This invention relates to the field of battery thermal management technology, and specifically to a method for preparing a thermally activated battery with a silicon-aluminum alloy high-temperature phase change material. Background Technology

[0002] Thermally activated batteries are characterized by rapid activation, high current density, high specific power, high specific energy, wide operating temperature range, and compact structure, making them widely used in military and civilian power supply fields. However, domestically produced thermally activated batteries currently face development bottlenecks such as short thermal life, poor thermal shock resistance, and high thermal radiation intensity. Short thermal life is caused by rapid heat dissipation, which shortens the battery's operating time. Poor thermal shock resistance leads to unstable battery output, affecting the operational status or accuracy of weapons and systems. High thermal radiation intensity causes elevated battery surface temperature, resulting in poor concealment and increased detection by infrared detectors. These bottlenecks significantly constrain the operational efficiency and safety of weapons and systems.

[0003] Thermally activated batteries typically utilize ignition methods such as the exothermic oxidation of iron powder to release a large amount of heat energy in a short time, stimulating the melting of the molten salt electrolyte to establish a conductive circuit. The electrolyte's melting point limits the cell's operating temperature to around 550°C. If the temperature is too low, the electrolyte solidifies and the battery fails; if it is too high, thermal runaway occurs, potentially leading to fire or even explosion. Therefore, battery heat management is necessary, including maintaining the battery's operating temperature and mitigating the impact of peak ignition heat.

[0004] Currently, thermal management of thermally activated batteries mainly focuses on the design of the heating source, insulation layer, and thermal buffer layer. For example, the invention patent CN109546173A, "A Method for Preparing and Applying a Heating Material for Uniform Heating in a Thermal Battery," describes a method of mixing and dispersing ignition material powder with molten salt electrolyte to ensure uniform heating of the heating source, thereby preventing localized overheating and runaway. The invention application CN113054213A, "A Method for Reducing the Surface Temperature of a Thermal Battery," describes the use of aluminum foil insulation sleeves and silica nanofiber aerogel as insulation layers, reducing heat dissipation from the battery surface after ignition, thus extending the duration of operating temperature and battery life.

[0005] In addition, as described in the invention patent CN109135684A entitled "A Composite Phase Change Material for Thermal Batteries and Its Preparation Method" and the withdrawn invention application CN109370561A entitled "A Photochromic Polyurethane Composite Material with UV Protection Function", both utilize the thermal conductivity and phase change heat absorption properties of carbon-based molten salt composite materials to provide thermal buffering for thermally activated batteries, thereby reducing the risk of overheating while lowering the battery surface temperature.

[0006] However, the above-mentioned thermal management from the perspective of heating source and insulation layer can only solve one of the problems such as local temperature runaway or excessive surface heat dissipation. It will also greatly increase the assembly difficulty and battery cost. Although the thermal buffer design based on molten salt phase change composite material can achieve the ideal thermal management effect, the required high thermal conductivity molten salt phase change material composite process is very complex. It often contains carbon skeleton thermally conductive filler, which has a very high risk of ignition at high operating temperatures. It still poses a considerable hidden danger for complex weapon and equipment systems. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a thermally activated battery with a silicon-aluminum alloy high-temperature phase change material. This battery possesses high thermal conductivity, high phase change enthalpy, and a suitable phase change temperature, enabling it to absorb excess heat during the ignition phase of the thermally activated battery, thus preventing thermal runaway. Simultaneously, it can reduce the maximum operating temperature of the battery surface and extend the battery's lifespan.

[0008] To solve the above-mentioned technical problems, the technical solution provided by the present invention is: a method for preparing a thermally activated battery with silicon-aluminum alloy high-temperature phase change material, comprising the following steps:

[0009] (1) Weigh out aluminum powder and silicon powder as raw materials according to a mass percentage of 70-90% Al and 10-30% Si respectively, and mix them evenly to obtain a mixed powder;

[0010] (2) The mixed powder obtained in step (1) is melted at high temperature under the protection of inert gas to obtain a liquid alloy;

[0011] (3) Defoaming and degranulation are performed on the liquid alloy obtained in step (2);

[0012] (4) Cool the liquid alloy that has undergone defoaming and degranulation treatment in step (3) to room temperature to obtain a solidified bulk alloy;

[0013] (5) The bulk alloy obtained in step (4) is sliced ​​according to the size of the thermally activated battery cell to obtain a sheet material of the corresponding size.

[0014] (6) The sheet obtained in step (5) is assembled into the battery body composed of thermally activated battery cells in a layered manner to obtain the finished thermally activated battery.

[0015] In the above technical solution, the phase transition temperature and enthalpy of the high-temperature alloy phase change material are controlled by adjusting the proportion of aluminum-silicon alloy, thereby achieving the effect of a customized heat buffer material suitable for the application scenario. The overall solution is simple and easy to implement, facilitating large-scale production. The prepared alloy phase change material has high thermal conductivity, suitable phase transition temperature, and phase transition enthalpy, thus possessing strong thermal management performance and effectively extending the battery's service life. In this solution, the alloy phase change material is cut and assembled into a thermally activated battery, which is characterized by low cost and simple operation. Combined with the high thermal conductivity and other advantages of the alloy phase change material, the battery's thermal management performance can be effectively achieved.

[0016] Further, in step (2), the mixed powder is heated in a plasma hot pressing sintering furnace.

[0017] Furthermore, in step (2), the inert gas is argon.

[0018] Furthermore, in step (3), the defoaming method is vacuum defoaming or high-temperature stirring defoaming. Vacuum defoaming is a non-contact defoaming method, which can save defoaming time and energy consumption and achieve a better defoaming effect.

[0019] Furthermore, in step (3), inert gas rinsing is used to remove particles. The gas flow rate is 30-50 m / s. The inert gas is argon. This can remove unmelted particles and purify the sample. Inert gas rinsing has the advantages of simple operation, high efficiency, low cost and good effect.

[0020] Furthermore, in step (2), the heating temperature is ≥1450℃.

[0021] Furthermore, in step (6), the thermally activated battery can be configured in parallel, series, or multiple connections. The configuration can be determined according to the actual application requirements. If a larger current is required, a parallel connection can be selected. If a higher voltage is required, a series connection can be selected. If complex requirements such as large current and high voltage are required, a multiple connection can be selected.

[0022] Furthermore, in step (6), the number of thermally activated battery cells and the number of cells can be adjusted according to the actual situation. The number of cells assembled with the alloy determines the thermal management efficiency of the battery. The more cells there are, the more energy the alloy phase change material can absorb, thereby controlling the battery operating temperature more effectively.

[0023] Compared with existing technologies, the significant advantages of this solution are:

[0024] 1. This solution uses alloy phase change materials to achieve battery thermal management, which has the advantages of being simple, easy to implement, and suitable for large-scale production;

[0025] 2. The alloy phase change material prepared by this method has high thermal conductivity, suitable phase change temperature and phase change enthalpy, thus having strong thermal management performance, which is conducive to controlling the surface temperature of the battery and extending the service life of the battery.

[0026] 3. In this solution, alloy phase change materials are cut and assembled into a thermally activated battery, which has the advantages of low cost, simple operation, and good performance. Attached Figure Description

[0027] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0028] Figure 1 This is a schematic diagram of the preparation method steps in the embodiments of the present invention;

[0029] Figure 2 The microstructure of the aluminum-silicon alloy in the embodiments of the present invention is shown.

[0030] Figure 3 The microstructure of the aluminum-silicon-magnesium alloy in the embodiments of the present invention is shown.

[0031] Figure 4 This is a schematic diagram illustrating the assembly style of the phase change sheet in a thermally activated battery according to an embodiment of the present invention. Detailed Implementation

[0032] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0033] like Figure 1 As shown, the preparation method of the thermally activated battery with silicon-aluminum alloy high-temperature phase change material according to the present invention includes the following steps:

[0034] (1) Weigh aluminum powder and silicon powder as raw materials according to a mass percentage of 70-90% Al and 10-30% Si, respectively, and mix them evenly to obtain a mixed powder; the silicon-aluminum alloy has high thermal conductivity, suitable phase transition temperature and adjustable phase transition enthalpy, and its property parameters are shown in the table below (e.g. Figure 2 As shown, Figure 2 The microstructure of the aluminum-silicon alloy in this embodiment is shown below, where the mass percentages of aluminum and silicon are 80% and 20%, respectively:

[0035] sample Phase transition peak temperature (°C) Phase transition enthalpy (J / g) <![CDATA[Al-Si 10 ]]> 575.3 512.7 <![CDATA[Al-Si 20 ]]> 572.3 520.5 <![CDATA[Al-Si 30 ]]> 572.1 443.3 <![CDATA[Al-Si 15 -Mg5]]> 480.3 119.7

[0036] (2) The mixed powder obtained in step (1) is placed in a plasma hot pressing sintering furnace under the protection of an inert gas, usually argon, and heated and melted at high temperature to obtain a liquid alloy; or it can be treated at high temperature in a vacuum environment. The heating temperature needs to be higher than the melting point of aluminum and silicon. The actual preparation process requires a temperature ≥1450℃, and in this embodiment it is 1500℃.

[0037] (3) Degas the liquid alloy obtained in step (2). The degassing method can be vacuum degassing or high-temperature stirring degassing. Vacuum degassing is a non-contact degassing method, which can save degassing time and energy consumption and achieve better degassing effect. Vacuum degassing is used in this embodiment. It is also necessary to remove particles from the liquid alloy by rinsing with inert gas, usually argon gas, with a gas flow rate of 30-50 m / s. The particle removal process can remove unmelted particles and purify the sample. Inert gas rinsing has the advantages of simple operation, high efficiency, low cost and good effect.

[0038] (4) Cool the liquid alloy that has undergone defoaming and degranulation treatment in step (3) to room temperature to obtain a solidified bulk alloy;

[0039] (5) The bulk alloy obtained in step (4) is sliced ​​according to the size of the thermally activated battery cell to obtain a sheet material of the corresponding size.

[0040] (6) Assemble the sheet obtained in step (5) into the battery body composed of thermally activated battery cells in a layered manner to obtain the finished thermally activated battery; here it is necessary to ensure that the surface of the cut alloy sheet is as flat and smooth as possible to reduce the interfacial thermal resistance between the battery cell and the alloy sheet.

[0041] The aluminum-silicon alloy obtained through the above scheme can be used as a thermal buffer material in the thermal management of thermally activated batteries, serving civilian and military fields such as electronics and communications, aerospace, and weaponry. The prepared high-temperature alloy composite phase change material exhibits high thermal conductivity, a suitable phase change temperature, and a high phase change enthalpy. Furthermore, by doping with other metals such as magnesium, the relative temperature and phase change enthalpy of the alloy composite phase change material can be further controlled, achieving the goal of customizing buffer materials to suit specific application scenarios. Figure 3 As shown, Figure 3 The image shows the microstructure of an aluminum-silicon-magnesium alloy, wherein the mass percentages of aluminum, silicon, and magnesium are 80%, 15%, and 5%, respectively.

[0042] Furthermore, thermally activated batteries can be configured in parallel, series, or multiple connections. The configuration can be determined based on the actual application requirements. For example, parallel connection can be selected to obtain a larger current, series connection can be selected to obtain a higher voltage, and multiple connection can be selected to obtain complex requirements such as large current and high voltage.

[0043] The number of thermally activated battery cells and the number of sheets can be adjusted according to actual conditions. The number of alloy sheets determines the thermal management efficiency of the battery; more sheets allow the alloy phase change material to absorb more energy, thereby more effectively controlling the battery's operating temperature. In this embodiment, the diameter of the thermally activated battery cell is 52mm, and the voltage is 32V. Therefore, the alloy sheets need to be cut to a size of φ52*3mm. If the maximum surface temperature of the battery needs to be controlled at 200-250℃, one alloy sheet is assembled; if it needs to be controlled at 100-150℃, three alloy sheets are assembled; and if it needs to be controlled below 100℃, six alloy sheets can be assembled. Figure 4 The diagram shown is a schematic representation of the assembly style of the alloy sheet, i.e., the phase change sheet, in the thermally activated battery in this embodiment.

[0044] Compared with existing technologies, the significant advantages of this solution are:

[0045] 1. This solution uses alloy phase change materials to achieve battery thermal management, which has the advantages of being simple, easy to implement, and suitable for large-scale production;

[0046] 2. The alloy phase change material prepared by this method has high thermal conductivity, suitable phase change temperature and phase change enthalpy, thus having strong thermal management performance, which is conducive to controlling the surface temperature of the battery and extending the service life of the battery.

[0047] 3. In this solution, alloy phase change materials are cut and assembled into a thermally activated battery, which has the advantages of low cost, simple operation, and good performance.

[0048] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a thermally activated battery using a silicon-aluminum alloy high-temperature phase change material, characterized in that, Includes the following steps: (1) Weigh out aluminum powder and silicon powder as raw materials according to a mass percentage of 70-90% Al and 10-30% Si respectively, and mix them evenly to obtain a mixed powder; (2) The mixed powder obtained in step (1) is melted at high temperature under the protection of inert gas to obtain a liquid alloy; (3) Defoaming and degranulation are performed on the liquid alloy obtained in step (2); (4) Cool the liquid alloy that has undergone defoaming and degranulation treatment in step (3) to room temperature to obtain a solidified bulk alloy; (5) The bulk alloy obtained in step (4) is sliced ​​according to the size of the thermally activated battery cell to obtain a sheet material of the corresponding size. (6) The sheet obtained in step (5) is assembled into the battery body composed of thermally activated battery cells in a layered manner to obtain the finished thermally activated battery. In step (6), the number of thermally activated battery cells and the number of sheets are adjusted according to the actual situation.

2. The method for preparing a thermally activated battery with a silicon-aluminum alloy high-temperature phase change material according to claim 1, characterized in that, In step (2), the mixed powder is heated in a plasma hot pressing sintering furnace.

3. The method for preparing a thermally activated battery with a silicon-aluminum alloy high-temperature phase change material according to claim 1, characterized in that, In step (2), the inert gas is argon.

4. The method for preparing a thermally activated battery with a silicon-aluminum alloy high-temperature phase change material according to claim 1, characterized in that, In step (3), the defoaming method is vacuum defoaming or high-temperature stirring defoaming.

5. The method for preparing a thermally activated battery with a silicon-aluminum alloy high-temperature phase change material according to claim 1, characterized in that, In step (3), inert gas is used to remove particles by flushing, and the gas flow rate is 30-50 m / s. The inert gas is argon.

6. The method for preparing a thermally activated battery with a silicon-aluminum alloy high-temperature phase change material according to claim 1, characterized in that, In step (2), the heating temperature is ≥1450℃.

7. The method for preparing a thermally activated battery with a silicon-aluminum alloy high-temperature phase change material according to claim 1, characterized in that, In step (6), the thermally activated batteries are configured in parallel, series, or multiple connections.

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