Packaging electrolyte injection method for improving pole piece infiltration and side deformation of pouch cell

Abstract

The invention relates to a packaging electrolyte injection method for improving the pole piece infiltration and side deformation of a pouch cell. The method includes disposing an electrolyte-injectionport at the bottom of the core of a pouch cell; orienting the head of the core of the pouch cell to the vertically downward direction. On the one hand, the electrolyte flows from the bottom of the core to the head of the core along a gap between the pole pieces of the core or a gap between the pole pieces and a diaphragm during an electrolyte injection process, thereby contributing to the uniforminfiltration of the pole pieces of the core. On the other hand, during the electrolyte injection process, the head of the core is oriented downward so as to help to increase the ring-rush strength ofthe core, avoid the deformation of the core, and further help to prolong the cycle life of the pouch cell.

Description

technical field [0001] The invention belongs to the field of battery manufacturing, and relates to a packaging liquid injection method for improving the infiltration of pole pieces and side deformation of soft package wound batteries. Background technique [0002] Lithium-ion batteries have been widely used in mobile phones, notebook computers, charging treasures, power tools, electric vehicles and other fields due to their high monomer voltage, high specific energy, long cycle life, good safety performance, and low self-discharge. For a wide core (width ratio length ≥ 1) wound in a soft package, after the core is injected with liquid, when the core absorbs liquid, due to the large length and width of the core, after the electrolyte is injected from the side, it is very difficult to It is difficult to be absorbed evenly by the middle position of the pole piece, which affects the wetting effect of the pole piece. Poor electrolyte infiltration will cause the ion transmission ...

AI Technical Summary

Problems solved by technology

For a wide core (width ratio length ≥ 1) wound in a soft package, after the core is injected with liquid, when the core absorbs liquid, due to the large length and width of the core, after the electrolyte is injected from the side, it is very difficult to Difficult to be evenly absorbed by the middle position of the pole piece, affecting the wetting effect of the pole piece

Poor electrolyte infiltration will cause the ion transmission path to become farther, thereby hindering the shuttle of lithium ions between the positive and negative electrodes

The electrochemical reaction of the pole piece with poor electrolyte infiltration is affected, and the battery interface impedance increases, which affects the battery rate, discharge capacity and cycle life

The wide and thin winding core is placed on the side. Before the battery is degassed, the battery diaphragm and the pole piece are not completely bonded and shaped, which is affected by gravity, resulting in the deformation of the battery close to the air bag.

[0003] CN202434586U discloses a soft package battery packaging structure, which is composed of a battery case and an aluminum-plastic film. The aluminum-plastic film is divided into upper and lower layers, and an opening is left on one side. The battery case is fixed between the upper and lower layers of aluminum-plastic film, and Keep a distance from each edge of the aluminum-plastic film; the liquid injection port of the pouch battery described in this scheme is set on the side of the winding core, and the liquid injection process has the problems of uneven wetting of the winding core pole piece and deformation of the pole piece, so Affect the performance of pouch battery

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