Development Of The Polymer Lithium-ion Batteries

With the miniaturization and lighten of the electronic equipments, the required batteries are becoming smaller and thinner. Polymer Li-ion batteries are born to meet this development. This paper is concentrated on research of technology and characteristics of polymer Li-ion battery's separator. We have done a lot of experiment and discussion of choosing, producing, technology and interaction of the ingredients. And the purpose for our research is to develop the production of polymer Li-ion batteries. The main conclusions are as below: By adopting controlling evaporation deposition to produce the P(VDF-HFP). This method adopts the boiling point difference between the solvent and non-solvent to get the separator by evaporation. This electrolyte separator doesn't have the safety problem caused by heat melting protection of polyethylene and polypropylene compound separator. By spreading PVDF on PP/PE/PP can make the separator hole closed to make the battery open circuit in order to avoid the heating, explosion caused by the subsidiary reaction of the battery, and guarantee the safety of the battery. We have found the influence of DMC and SiO2 to electrolyte. The different quantities of DMC and SiO2 in the production process of the separator can improve the conductivity of electrolyte. We have discussed the conduction principle of compound electrolyte. By adopting the test of conductivity of electrolyte, and combining with the test results of XRD, SEM, we got a conclusion that the electrolyte is in liquid state in normal temperature and in higher temperature, the electrolyte's peristalsis can increase the conductance. We have got the production technology of polymer Li-ion battery: mixing the materials, making slurry, grinding, dealing the collectors, plates production, convolution of the plates, heat sealing, electrolyte injecting, vacuum sealing, activation and so on, we also got the technical parameters of every step, and gave detailed explanation of some important steps. The new type polymer Li-ion batteries we developed only have little capacity loss, good cycle life, little daily self-discharge The batteries can meet the requirements of batteries for mobile phones, palm computer, notebook and other portable equipments.