Soft package battery and manufacturing method thereof

Abstract

The invention relates to the technical field of soft package batteries, and discloses a soft package battery and a manufacturing method thereof, and the soft package battery comprises a battery cell body, an aluminum plastic film and a reinforcing layer. A punching pit for accommodating the battery cell body is formed in the aluminum-plastic film, and the battery cell body is packaged in the punching pit in the aluminum-plastic film; the reinforcing layer is clamped between the battery cell body and the aluminum-plastic film, the reinforcing layer is located in the punching pit, and the thickness of the reinforcing layer is smaller than the depth of the punching pit. The battery cell body of the soft package battery is packaged in the punching pit of the aluminum-plastic film, and the enhancement layer with the thickness smaller than the depth of the punching pit is additionally arranged in the punching pit of the aluminum-plastic film, so that the mechanical strength of the soft package battery is improved, and the soft package battery is not easy to deform and higher in safety; moreover, after the soft package battery is packaged, the gap between the battery cell body and the aluminum-plastic film is filled with the reinforcing layer, so that the positive plate, the diaphragm and the negative plate of the battery cell body are pre-tightened, the positive plate, the diaphragmand the negative plate are attached more tightly, and the electrochemical performance of the soft package battery is further improved.

Description

technical field [0001] The invention relates to the technical field of pouch batteries, in particular to a pouch battery and a manufacturing method thereof. Background technique [0002] The pouch battery is packaged in aluminum-plastic film, which has good flexibility. When there is a safety problem with the pouch battery, it will generally only blow up and crack, and it will not cause an explosion and fire because the gas cannot be discharged. Moreover, for vehicles, the advantages of light weight of pouch batteries are conducive to improving the cruising range of vehicles. [0003] However, there are also some shortcomings in the packaging structure of the existing pouch battery, which further affects the overall performance of the pouch battery. The main performances are as follows: 1. Before packaging the bare cell with the aluminum-plastic film, it is usually necessary to punch out a punching hole on the aluminum-plastic film to accommodate the bare cell; however, du...

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Problems solved by technology

[0003] However, the packaging structure of the existing pouch battery also has some shortcomings, which in turn affects the overall performance of the pouch battery

The main performances are as follows: 1. Before packaging the bare cell with the aluminum-plastic film, it is usually necessary to punch out a punching hole on the aluminum-plastic film to accommodate the bare cell; however, due to the low strength of the aluminum-plastic film itself, after stamping The thickness of the nylon layer, AL layer (aluminum foil layer), and PP layer (also known as the electrolyte-resistant layer, whose material is mainly polypropylene) of the treated aluminum-plastic film will change, which will lead to mechanical damage of the aluminum-plastic film. The decrease in strength makes the pouch battery easy to deform and lowers the safety; 2. Due to the general redundancy of the stamping pit depth, the bare cell and the stamped aluminum-plastic film are not completely bonded, and gaps will be generated , which in turn reduces the mechanical strength of the pouch battery; 3. Bare cells mainly include positive electrodes, separators and negative electrodes

The larger the distance between the positive electrode sheet and the negative electrode sheet, the lower the electron transfer efficiency between the positive electrode sheet and the negative electrode sheet, and the poorer the electrochemical performance of the pouch battery; There are gaps between the aluminum-plastic films, which will lead to insufficient compression force on the positive electrode sheet, separator, and negative electrode sheet of the bare cell, while the positive electrode sheet and the negative electrode sheet are prone to produce large gaps, which will reduce the electrochemical performance of the pouch battery

Moreover, for pouch batteries with a fluffy structure, after long-term cycling, the thickness of the positive and negative electrodes of the bare cell will increase due to repeated intercalation and extraction of lithium ions, which will further expand the distance between the positive and negative electrodes. , which ultimately makes the electrochemical performance of the pouch battery worse

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