A kind of thin thermal battery separator and its preparation method

Abstract

The invention relates to a thin type thermal battery isolation sheet and a preparation method therefor. According to the method, the thin type thermal battery is prepared by adopting an electrolyte salt saturation solution wetting substrate, so that it is possible that a fused salt electrolyte, which can be dissolved extremely easily in moisture absorption, can be prepared into the isolation sheet; the method does not need a rigorous operating environment, and is high in repeatability, low cost and capable of preparing isolation sheets of different thicknesses according to needs; and meanwhile, the prepared thermal battery isolation sheets are more thinned, and the thicknesses of the isolation sheets are adjustable within a range of 150 to 350[mu]m, so that the activation time of the thermal battery can be effectively shortened, and the high-power discharging capability can be effectively improved.

Description

technical field [0001] The invention belongs to the technical field of thermal battery preparation, and in particular relates to a process method for preparing a thinned thermal battery separator by soaking in a saturated solution. Background technique [0002] The thermal battery is a heat-activated primary reserve power supply that enters the working state by heating and melting the solid salt electrolyte into an ionic conductor; the thermal battery has high power discharge, high specific energy, high specific power, wide operating environment temperature, long storage time, Due to the characteristics of quick and reliable activation and compact structure, it has become an ideal power supply for modern weapons (missiles, torpedoes, strategic weapons, etc.), and occupies a very important position in military power supplies. [0003] At present, lithium-based thermal batteries are the leading products of thermal batteries. They can be simply regarded as composed of positive ...

AI Technical Summary

Problems solved by technology

[0003] At present, lithium-based thermal batteries are the leading products of thermal batteries. They can be simply regarded as composed of positive electrodes, molten salt electrolytes and negative electrodes. When the operating temperature is higher than the melting point of the electrolyte salt, the electrolyte will melt and flow, and the battery will be activated; However, the flow of electrolyte generates electrical noise, accelerates self-discharge, and in serious cases causes battery short circuit, which has a negative impact on battery discharge performance; therefore, the separator, as a key part of the thermal battery, directly affects the working life and safety performance of the battery.

[0004] At present, in order to suppress the flow of the electrolyte, chemically inert substances (such as MgO) with a large specific surface area are usually added to the electrolyte to inhibit the flow of the electrolyte; however, the diameter of the separator prepared by this method is limited. The internal resistance is large during the process, and the high-power discharge capacity is not good

[0005] Moreover, the ideal electrolyte for a thermal battery must not only have good electronic insulation to isolate the positive and negative electrode materials, but also provide a stable ion transmission channel; considering the high temperature working conditions of the thermal battery and the extremely strong In order to ensure the efficient and safe operation of the battery, the insulating material in the electrolyte of the thermal battery must use a material with good insulation, strong chemical stability and thermal stability; however, the existing thermal battery electrolyte material is usually made of magnesium oxide (MgO) and electrolyte salts lithium chloride and potassium chloride are mixed according to a certain proportion for powder compression. The main problem is that the powder is poor in self-supporting property, its mechanical strength is poor, and its shrinkage and bending properties are easily affected at high temperatures. Causes a short circuit in the battery, so the thickness cannot be too thin, which increases the battery volume and severely limits the development of thermal battery miniaturization

At the same time, during the discharge process of this type of thermal battery, the electrolyte leakage rate changes greatly, which makes the polarization internal resistance of the battery change greatly, resulting in poor power performance.

[0006] At the same time, the electrolyte salt is very easy to absorb moisture and dissolve. Therefore, thermal battery separators at home and abroad are prepared by powder pressing technology. Therefore, the thinning thermal battery separator becomes one of the important problems that need to be solved urgently in the miniaturization of thermal batteries in the future

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