As very clear was shown in the recent years - the battery soft shorting and overheating problem cannot be identified at a time when battery was manufacturing. Only after prolonged cycling (usage) this phenomena may occur.
Market forces battery manufacturers to extend battery life, achieve higher energy densities and faster charging times. This will force engineers to design higher density electrode and use thinner and higher porosity separators. The fact is the energy densities are double what they were five years ago using the same materials.
The battery separator plays an important role by regulating cell kinetics, allowing ionic flow, preventing electronic contact between the two ...view middle of the document...
One is to use non-woven polymer mat. As polymer base here it may be PET [Degussa] with ceramic coating, PAN ,
On the other hand, if the separator film is mono-liyer (i.e. with )
Slurry: Mixing sequence: PVdF-HFP with acetone stirred at room temperature until polymer will totally dissolved; appropriate amount of the ethanol slowly added (by drops) and well stirred. Ceramic powder slowly added to get uniform and homogeneous dispersion in the slurry. All operation have been done at room temperature and ambient humidity. Thus prepared slurry was poured in to dip coater`s container and coating have been performed. Separator coating: Coated layer thickness was controlled by line speed and air flow rate. Optimal conditions was estimated by obtaining layer thickness in the range of 4-6 um with good adhesion to separator base film. Thickness of the ceramic layer depends on line speed (as well slurry viscosity); layer adhesion depends on (a) ceramic/polymer binder ratio, (b) air flow rate, (c) solvent/non-solvent ratio. Optimal conditions to obtain desirable quality of the ceramic layer have been found by changing all that parameters. Electrochemical and thermal performances test: Electrolyte conductivity measurements...