Packaging film, and polymer lithium battery packaged with packaging film

Abstract

The invention discloses a packaging film, and a polymer lithium battery packaged with the packaging film. The packaging film is formed by an outer protection layer, an outer bonding layer, a silicon plastic film, an inner bonding layer and a CPP layer. The polymer lithium battery using the packaging film is formed by a positive electrode sheet, a negative electrode sheet, a diaphragm, an electrolyte and the packaging film. The packaging film is characterized in that the silicon plastic film replaces a traditional aluminum plastic layer. The silicon plastic film has the advantages of excellent water and gas resistance, good ductility, good plasticity, no electrical conductivity, improvement of the short circuit and other disadvantages of the aluminum plastic film, appearing in the inner layer rupture layer, and realization of high safety and high reliability of the battery.

Description

technical field [0001] The invention belongs to the field of lithium ion battery materials, and in particular relates to a polymer lithium battery packaging film. Background technique [0002] Polymer lithium battery has high energy density and good safety performance, and is the main energy provider for digital products. It is widely used and occupies a very important position in battery products. At present, the vast majority of polymer lithium batteries on the market are packaged with aluminum-plastic film. Aluminum-plastic film is light in weight, good in sealing, and large in deformation, which can prevent battery explosion and has been widely used. [0003] But in the actual use process, we also found a lot of problems. As the name implies, there is a layer of aluminum in the aluminum-plastic film, and aluminum is a good conductor of electricity. Once the other layers of the aluminum-plastic film are broken, it is easy to cause a short circuit in the battery, especi...

AI Technical Summary

Problems solved by technology

As the name implies, there is a layer of aluminum in the aluminum-plastic film, and aluminum is a good conductor of electricity. Once the other layers of the aluminum-plastic film are broken, it is easy to cause a short circuit in the battery, especially at the tabs. The positive and negative tabs are in contact with the aluminum layer at the same time. cause serious consequences

[0004] Moreover, once the inner layer of the aluminum-plastic film is broken, in the acidic electrolyte environment, "primary battery" corrosion spots will be formed on the surface of the aluminum layer. In severe cases, the aluminum layer will be perforated, and the battery's airtightness will deteriorate, and external air and water will penetrate into the battery. , causing the battery to be scrapped

[0005] Aluminum-plastic film has a certain degree of plasticity, but it must be stamped through a mold, which increases the production cost, and after the aluminum is stretched, the corners become thinner, the reliability deteriorates, and it is easy to break from the corners

[0006] Also, in the actual production process, the appearance of the aluminum-plastic film is easily damaged. A light bump or even scratched by a fingernail will leave scratches on the surface of the battery, and these batteries are usually not accepted by customers.

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