From the general requirements for flexible packaging materials of the polymerized ion battery described above, it can be found that the flexible packaging material required for manufacturing has a high degree of difficulty:
First of all, the requirements for barrier properties of flexible packaging materials are 10,000 times higher than those of common aluminum-plastic composite materials. Such high barrier properties are difficult to meet with the requirements of ordinary composite materials and composite technologies. It is generally necessary to use extremely thick aluminum foil and use a composite material of 4 to 7 layers in order to apply a variety of composite technologies.
For example, in the same material production process, it may be necessary to adopt the dry complex method, the extrusion method, the continuous extrusion compound method, the triple extrusion method, the thermal compound method or the rogue compound method, and the multi-layer co-extrusion method. In this way, higher requirements are placed on the production technology of flexible packaging materials.
Second, the choice of composite inner heat seal material. The electrolyte used in polymer lithium-ion batteries consists of a variety of esters that make up the organic electrolyte, in which the electrolyte is hydrolyzed in the presence of moisture to form highly acidic substances. According to the principle of similar compatibility, ester-based organic materials and many heat-sealable materials have swellability. Low-melting heat-sealable materials that do not react with the electrolyte and must have sufficiently strong acid resistance are more difficult to find.
In addition, the design of packaging materials is difficult. In the process of designing flexible packaging materials, it is necessary to ensure that the above-mentioned five requirements are satisfied, but also to ensure that the production of flexible packaging materials can be achieved, but also to take into account the impact of flexible packaging materials on polymer lithium-ion batteries and the development of polymer lithium-ion batteries Trends (in order to continuously develop the required flexible packaging materials) are more difficult.
Finally, the quality of flexible packaging materials has a long period of time. The water resistance required by the polymer lithium ion battery. Oxygen barrier performance exceeds the minimum accuracy of the tester in the packaging field, so it is difficult to quantitatively test the developed flexible packaging material. What is generally used today is the final determination of the actual packaging battery. According to the inspection characteristics of the battery and the degree of influence of the flexible packaging material on the battery and the impact rate, it is generally required that the final test of the compliance of the flexible packaging material lasts for more than three months.