The present invention relates to a method for stabilizing aqueous dispersions, notably of polymers based on vinylidene fluoride (VDF), and to the use of the stabilized aqueous dispersion thus obtained in electrochemical applications.

The present invention relates to a method for stabilizing aqueous dispersions, notably of polymers based on vinylidene fluoride (VDF), and to the use of the stabilized aqueous dispersion thus obtained in electrochemical applications.

Disclosed are a separator that includes fibrils including a polyolefin; and bond structures generated by reacting at least some of a first radical formed on surfaces of the fibrils by a photoreactive material and a second radical formed in the photoreactive material, and a method of manufacturing the separator.

Disclosed are a separator that includes fibrils including a polyolefin; and bond structures generated by reacting at least some of a first radical formed on surfaces of the fibrils by a photoreactive material and a second radical formed in the photoreactive material, and a method of manufacturing the separator.

According to one embodiment, a separator is provided. The separator includes a composite membrane. The composite membrane includes a substrate layer, a first composite layer, and a second composite layer. The first composite layer is located on one surface of the substrate layer. The second composite layer is located on the other surface of the substrate layer. The composite membrane has a coefficient of air permeability of 1×10.sup.−14 m.sup.2 or less. The first composite layer has a first surface and a second surface. The first surface is in contact with the substrate layer. The second surface is located on an opposite side to the first surface. Denseness of a portion including the first surface is lower than denseness of a portion including the second surface in the first composite layer.

The present invention provides a nonaqueous electrolyte secondary battery porous layer which improves an initial battery characteristic immediately after initial charge and discharge of a nonaqueous electrolyte secondary battery. In the nonaqueous electrolyte secondary battery porous layer in accordance with an aspect of the present invention, a standard deviation of bursting strength is 0.6 or more and 11.0 or less.

In accordance with at least selected aspects, objects or embodiments, optimized, novel or improved membranes, battery separators, batteries, and/or systems and/or related methods of manufacture, use and/or optimization are provided. In accordance with at least selected embodiments, the present invention is related to novel or improved battery separators that prevent dendrite growth, prevent internal shorts due to dendrite growth, or both, batteries incorporating such separators, systems incorporating such batteries, and/or related methods of manufacture, use and/or optimization thereof. In accordance with at least certain embodiments, the present invention is related to novel or improved ultra thin or super thin membranes or battery separators, and/or lithium primary batteries, cells or packs incorporating such separators, and/or systems incorporating such batteries, cells or packs. In accordance with at least particular certain embodiments, the present invention is related to shutdown membranes or battery separators, and/or lithium primary batteries, cells or packs incorporating such separators, and/or systems incorporating such batteries, cells or packs.

In accordance with at least selected aspects, objects or embodiments, optimized, novel or improved membranes, battery separators, batteries, and/or systems and/or related methods of manufacture, use and/or optimization are provided. In accordance with at least selected embodiments, the present invention is related to novel or improved battery separators that prevent dendrite growth, prevent internal shorts due to dendrite growth, or both, batteries incorporating such separators, systems incorporating such batteries, and/or related methods of manufacture, use and/or optimization thereof. In accordance with at least certain embodiments, the present invention is related to novel or improved ultra thin or super thin membranes or battery separators, and/or lithium primary batteries, cells or packs incorporating such separators, and/or systems incorporating such batteries, cells or packs. In accordance with at least particular certain embodiments, the present invention is related to shutdown membranes or battery separators, and/or lithium primary batteries, cells or packs incorporating such separators, and/or systems incorporating such batteries, cells or packs.

Novel or improved microporous single or multilayer battery separator membranes, separators, batteries including such membranes or separators, methods of making such membranes, separators, and/or batteries, and/or methods of using such membranes, separators and/or batteries are provided. In accordance with at least certain embodiments, a multilayer dry process polyethylene/polypropylene/polyethylene microporous separator which is manufactured using the inventive process which includes machine direction stretching followed by transverse direction stretching and a subsequent calendaring step as a means to reduce the thickness of the multilayer microporous membrane, to reduce the percent porosity of the multilayer microporous membrane in a controlled manner and/or to improve transverse direction tensile strength. In a very particular embodiment, the inventive process produces a thin multilayer microporous membrane that is easily coated with polymeric-ceramic coatings, has excellent mechanical strength properties due to its polypropylene layer or layers and a thermal shutdown function due to its polyethylene layer or layers. The ratio of the thickness of the polypropylene and polyethylene layers in the inventive multilayer microporous membrane can be tailored to balance mechanical strength and thermal shutdown properties.

Novel or improved microporous single or multilayer battery separator membranes, separators, batteries including such membranes or separators, methods of making such membranes, separators, and/or batteries, and/or methods of using such membranes, separators and/or batteries are provided. In accordance with at least certain embodiments, a multilayer dry process polyethylene/polypropylene/polyethylene microporous separator which is manufactured using the inventive process which includes machine direction stretching followed by transverse direction stretching and a subsequent calendaring step as a means to reduce the thickness of the multilayer microporous membrane, to reduce the percent porosity of the multilayer microporous membrane in a controlled manner and/or to improve transverse direction tensile strength. In a very particular embodiment, the inventive process produces a thin multilayer microporous membrane that is easily coated with polymeric-ceramic coatings, has excellent mechanical strength properties due to its polypropylene layer or layers and a thermal shutdown function due to its polyethylene layer or layers. The ratio of the thickness of the polypropylene and polyethylene layers in the inventive multilayer microporous membrane can be tailored to balance mechanical strength and thermal shutdown properties.