A nonaqueous electrolyte secondary battery separator having excellent impact absorbency includes a polyolefin porous film having a full width W at half maximum of a peak of an MD component of not less than 30 degrees. The full width W at half maximum of the peak of the MD component is calculated from an azimuthal profile of a scattering peak on a plane obtained by wide-angle X-ray scattering measurement that is carried out by irradiating a surface of the polyolefin porous film with an X-ray from a direction vertical to the surface of the polyolefin porous film, and/or having a maximum-to-minimum intensity ratio r of not more than 3.6. The maximum-to-minimum intensity ratio r is calculated from a Fourier transformed azimuthal profile obtained by observing the surface of the polyolefin porous film by SEM.

A nonaqueous electrolyte secondary battery separator having excellent impact absorbency includes a polyolefin porous film having a full width W at half maximum of a peak of an MD component of not less than 30 degrees. The full width W at half maximum of the peak of the MD component is calculated from an azimuthal profile of a scattering peak on a plane obtained by wide-angle X-ray scattering measurement that is carried out by irradiating a surface of the polyolefin porous film with an X-ray from a direction vertical to the surface of the polyolefin porous film, and/or having a maximum-to-minimum intensity ratio r of not more than 3.6. The maximum-to-minimum intensity ratio r is calculated from a Fourier transformed azimuthal profile obtained by observing the surface of the polyolefin porous film by SEM.

A solid-state battery is provided with a solid electrolyte membrane-protecting member, which compensates for a difference in area between an electrode and a solid electrolyte membrane, and thus the end portion of the solid electrolyte membrane is supported by the solid electrolyte membrane-protecting member. Even when the solid electrolyte membrane has low mechanical strength or has low shape stability due to high flexibility, the end portion of the solid electrolyte membrane may be supported by the solid electrolyte membrane-protecting member, and it is possible to prevent damage of the end portion of the solid electrolyte membrane. The present disclosure also relates to a method for manufacturing the solid-state battery. According to the method, the solid electrolyte membrane-protecting member may be disposed in the portion corresponding to a difference in area between the electrode and the solid electrolyte membrane through a simple and convenient process.

A solid-state battery is provided with a solid electrolyte membrane-protecting member, which compensates for a difference in area between an electrode and a solid electrolyte membrane, and thus the end portion of the solid electrolyte membrane is supported by the solid electrolyte membrane-protecting member. Even when the solid electrolyte membrane has low mechanical strength or has low shape stability due to high flexibility, the end portion of the solid electrolyte membrane may be supported by the solid electrolyte membrane-protecting member, and it is possible to prevent damage of the end portion of the solid electrolyte membrane. The present disclosure also relates to a method for manufacturing the solid-state battery. According to the method, the solid electrolyte membrane-protecting member may be disposed in the portion corresponding to a difference in area between the electrode and the solid electrolyte membrane through a simple and convenient process.

This application provides a secondary battery, including at least one battery unit assembly. The battery cell assembly includes a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate. An elongation rate of the separator is greater than 100%, the elongation rate of the separator includes an elongation rate in the length direction and/or an elongation rate in the width direction, a ratio of the elongation rate of the separator to a thickness of the active material layer of the positive electrode plate and/or negative electrode plate is 3.0%/.Math.m to 8.0%/.Math.m, and a ratio of the elongation rate of the separator to an elongation rate of the current collector of the positive electrode plate and/or negative electrode plate is greater than or equal to 60.

A method for formation of cylindrical and prismatic can cells may include providing a battery, where the battery includes one or more cells, with each cell including at least one silicon-dominant anode, a cathode, and a separator. The battery also includes a metal can that contains the one or more cells such that during formation a pressure between 50 kPa and 1 MPa is applied to the one or more cells. The battery may include strain absorbing materials arranged between the one or more cells and interior walls of the can. The strain absorbing materials may include foam. The strain absorbing materials may include a solid electrolyte layer. The strain absorbing materials may include PMMA, PVDF, or a combination thereof. The pressure during a formation process may be due to a thickness of the strain absorbing materials being thicker than an expansion of the one or more cells.

A method for formation of cylindrical and prismatic can cells may include providing a battery, where the battery includes one or more cells, with each cell including at least one silicon-dominant anode, a cathode, and a separator. The battery also includes a metal can that contains the one or more cells such that during formation a pressure between 50 kPa and 1 MPa is applied to the one or more cells. The battery may include strain absorbing materials arranged between the one or more cells and interior walls of the can. The strain absorbing materials may include foam. The strain absorbing materials may include a solid electrolyte layer. The strain absorbing materials may include PMMA, PVDF, or a combination thereof. The pressure during a formation process may be due to a thickness of the strain absorbing materials being thicker than an expansion of the one or more cells.

In accordance with at least certain embodiments, the present invention is directed to novel, improved, coated, or treated separator membranes, separators or membrane based separators for lithium batteries. The membranes or separators may include non-woven layers, improved surfactant treatments, or combinations thereof. The separators or membranes are useful for solvent electrolyte lithium batteries, especially rechargeable lithium ion batteries, and provide improved performance, wettability, cycling ability, and/or recharging efficiency.

In accordance with at least certain embodiments, the present invention is directed to novel, improved, coated, or treated separator membranes, separators or membrane based separators for lithium batteries. The membranes or separators may include non-woven layers, improved surfactant treatments, or combinations thereof. The separators or membranes are useful for solvent electrolyte lithium batteries, especially rechargeable lithium ion batteries, and provide improved performance, wettability, cycling ability, and/or recharging efficiency.

A multi-layered battery separator for a lithium secondary battery includes a first layer of a dry processed membrane bonded to a second layer of a wet processed membrane. The first layer may be made of a polypropylene based resin. The second layer may be made of a polyethylene based resin. The separator may have more than two layers. The separator may have a ratio of TD/MD tensile strength in the range of about 1.5-3.0. The separator may have a thickness of about 35.0 microns or less. The separator may have a puncture strength of greater than about 630 gf. The separator may have a dielectric breakdown of at least about 2000V.