Lithium ionic cell separator packaging method

Abstract

The invention discloses a diaphragm sealing method of a lithium ion battery. The technology proposal is that both two sides and the periphery of an anode plate and a cathode plate are wrapped by polyethylene and polypropylene diaphragm, the length and the width of the diaphragms can be first cut into a size larger than the anode plate and the cathode plate, the two sides of the anode plate or the cathode plate are surrounded by the diaphragms, and then the extending part of the diaphragm is combined together by thermosynthesis; or the diaphragms are prepared into pockets, the anode plate or the cathode plate is put into the pockets and the mouths of the pockets are sealed. The sealing method of the invention is used in the preparation of lithium ion batteries; as the diaphragms wrap the periphery of the anode plate and the cathode plate, the diaphragms can not shrink when the temperature of the battery rises so as to avoid the accident as a result of short circuit of the anode plate or the cathode plate, thereby improving the safety and reliability of the lithium ion battery in high temperature.

Description

technical field [0001] The invention relates to a method for assembling a lithium-ion battery cell, in particular to a packaging method for a diaphragm in the cell. Background technique [0002] Lithium-ion batteries have excellent performance and are widely used, and their cell assembly is very important. In assembly, the positive and negative electrodes and the diaphragm sandwiched between the positive and negative electrodes are generally rolled up together, or stacked in layers, and then the tabs are welded on the positive and negative electrodes to form a battery cell. At present, the commonly used separators are made of polyethylene or polypropylene plastic. Since the separators in the existing assembly method are single-sheet flat sandwiched between the pole pieces, when the temperature of the battery rises for some reason, the separator will Shrinkage, resulting in a short circuit between the positive and negative electrodes, the short circuit accelerates the temper...

AI Technical Summary

Problems solved by technology

At present, the commonly used separators are made of polyethylene or polypropylene plastic. Since the separators in the existing assembly method are single-sheet flat sandwiched between the pole pieces, when the temperature of the battery rises for some reason, the separator will Shrinkage, resulting in a short circuit between the positive and negative electrodes, the short circuit accelerates the temperature rise, and the diaphragm shrinks further. Such a vicious cycle eventually causes the battery to catch fire and explode.