Porous composite isolating film and preparation method thereof

Abstract

The invention discloses a porous isolating film which is composed of an organic component and an inorganic filler, wherein the inorganic filler contains hollow particles, the volume of the hollow part of each hollow particle is 1-95% of the total volume of the hollow particle, a shell of the hollow particle is in a porous structure, the porosity of the shell of the hollow particle is 1-90%, the intensity of pressure capable of being born by the hollow particles is greater than or equal to 0.05MPa, the hollow structure of the hollow filler can be used for storing electrolyte, so that the problem of hydro-expanding of a battery is alleviated or solved; meanwhile, the electrolyte stored in the hollow particles can be used for improving ion conduction property of the filler, so that a battery cell has excellent rate capability, and further, the safety performance of the battery is improved.

Description

technical field [0001] The invention belongs to the technical field of porous isolation membranes, in particular to a porous composite isolation membrane and a preparation method thereof. Background technique [0002] In 1991, Sony Corporation of Japan creatively adopted carbon materials as the anode material of lithium-ion batteries, which brought revolutionary changes in the field of lithium-ion batteries; And a lot of use on other portable electrical appliances. Lithium-ion batteries have many advantages, such as high voltage, small size, light weight, high specific capacity, no memory effect, no pollution, small self-discharge, long cycle life, etc. It is an ideal power source for mobile appliances and electric vehicles in the 21st century. Power supply and electric storage for storage power station. However, with the improvement of people's consumption demand, the requirements for the standby time of consumer electronic products are getting higher and higher, and corr...

AI Technical Summary

Problems solved by technology

[0004] However, as the compaction density of the electrode increases, the porosity in the electrode will gradually decrease, and the space for storing the electrolyte will become less, but in order to ensure the cycle performance of the battery, the liquid injection volume of the battery cell must remain unchanged, so There will be a problem of "fluid swelling", which will make the battery surface uneven, affecting the appearance of the battery until it becomes a defective product, which is especially obvious in the pouch battery

[0005] After the ceramic layer is coated on the electrode diaphragm or separator, under abuse conditions, the ceramic layer can effectively block the electronic conduction between the positive and negative electrodes, resulting in high-current discharge and heat generation, thereby improving the safety performance of the battery cell ; However, due to the increase of the ceramic treatment layer, the thickness of the cell will be increased and the energy density of the cell will be reduced

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