Battery diaphragm preparation process capable of increasing ion exchange capacity

Abstract

The invention discloses a battery diaphragm preparation process capable of increasing ion exchange capacity. The battery diaphragm preparation process comprises the steps of step 1, preparing raw materials; step 2, conducting melt extrusion; step 3, performing heat treatment; step 4, stretching step by step; step 5, conducting hot air shaping; step 6, conducting diaphragm cleaning; step 7, slitting and collecting; step 8, conducting diaphragm modification; and step 9, cleaning and drying. According to the invention, the diaphragm is modified through a modifier, and the hydrophilicity of the diaphragm is improved. Meanwhile, lignosulfonate is added into the modifier, the ion exchange capacity of the diaphragm is improved, the charging and discharging efficiency of a battery is improved, dust and particles on the surface of the diaphragm are brushed away through a brush, and the diaphragm is prevented from being scratched by the dust and the particles. The influence of particles and duston the modification effect is reduced at the same time, the modified diaphragm is soaked with a potassium hydroxide solution and washed with pure water multiple times, the unreacted modifier and particles on the surface of the diaphragm are removed, and the quality of the diaphragm is improved.

Description

technical field [0001] The invention relates to the technical field of diaphragm preparation, in particular to a preparation process for a battery diaphragm that increases ion exchange capacity. Background technique [0002] In the structure of a lithium battery, the diaphragm is one of the key inner components. The main function of the diaphragm is to separate the positive and negative electrodes of the battery to prevent the two electrodes from contacting and short circuit. In addition, it also has the function of allowing electrolyte ions to pass through. The material is non-conductive, and its physical and chemical properties have a great influence on the performance of the battery. Different types of batteries require different separators. For lithium battery series, since the electrolyte is an organic solvent system, a separator material that is resistant to organic solvents is required. [0003] The battery separator is generally made of polyethylene and polypropylen...

AI Technical Summary

Problems solved by technology

[0003] The battery separator is generally made of polyethylene and polypropylene materials. In addition to separating the positive and negative electrodes, the battery separator also has the function of allowing ions to pass through contact with the electrolyte. Strong hydrophobicity is not conducive to the infiltration of the electrolyte, which increases the internal resistance of the battery, thereby reducing the ion exchange capacity and reducing the discharge efficiency of the battery. Therefore, it is necessary to modify the diaphragm. However, direct modification, the surface of the diaphragm Impurities and dust on the surface of the diaphragm will be adsorbed on the surface of the diaphragm, which will cause scratches on the diaphragm, and even cause the micropores on the surface of the battery diaphragm to be blocked, which greatly reduces the effect of modification. At the same time, after irradiation modification, the residual modifier adheres to the battery On the surface of the diaphragm, dust and particles in the air will also adhere to the surface of the diaphragm, reducing the quality of the diaphragm

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