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...

Examples

Embodiment 1

[0007] Embodiment 1: first punch the coated positive and negative electrode sheets into rectangular sheets with the same shape and size, adopt the scheme of the present invention, cut the polyethylene separator to a size 3mm larger than the negative electrode sheet in length and width, and use two One piece of diaphragm wraps the two sides of a negative electrode sheet, and then thermally integrates the protruding parts around the diaphragm, leaving the welding position of the tabs, and then alternately overlaps the positive electrode sheet and the wrapped negative electrode sheet according to the conventional method, and assembles Battery.

Embodiment 2

[0008] Example 2: Make a polypropylene separator into a bag with one side open, corresponding to the positive electrode, put the positive electrode into the bag, heat seal one side of the opening, leave the tab welding position, and then assemble it into a battery.

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...

Examples

Embodiment 1

[0007] Embodiment 1: first punch the coated positive and negative electrode sheets into rectangular sheets with the same shape and size, adopt the scheme of the present invention, cut the polyethylene separator to a size 3mm larger than the negative electrode sheet in length and width, and use two One piece of diaphragm wraps the two sides of a negative electrode sheet, and then thermally integrates the protruding parts around the diaphragm, leaving the welding position of the tabs, and then alternately overlaps the positive electrode sheet and the wrapped negative electrode sheet according to the conventional method, and assembles Battery.

Embodiment 2

[0008] Example 2: Make a polypropylene separator into a bag with one side open, corresponding to the positive electrode, put the positive electrode into the bag, heat seal one side of the opening, leave the tab welding position, and then assemble it into a battery.