Abstract: A pouch-type secondary battery and a method of manufacturing same are capable of completely protecting a metal layer from moisture or air by forming an insulating coating layer including a conformal coating layer on the metal layer exposed at a cut surface of a battery case. The method includes a first step of preparing a battery case including an upper case and a lower case by cutting a laminate sheet including an outer coating layer, a metal layer, and an inner coating layer; a second step of receiving an electrode assembly between the upper case and the lower case; a third step of forming a sealing portion by contacting outer peripheries of the upper case and the lower case; and a fourth step of forming a conformal coating layer on a side surface of the sealing portion so as to prevent exposure of the metal layer.

Abstract: A separator for an electrochemical device and an electrochemical device comprising the same. The separator comprises a porous polymer substrate and a heat resistant coating layer on at least one surface of the porous polymer substrate. The heat resistant coating layer is a porous polymer layer having pores, and comprises a polyvinyl pyrrolidone-based polymer and a polyvinylidene fluoride (PVDF)-based polymer.

Abstract: The present invention relates to a pouch exterior material which is for a lithium secondary battery and includes an inner layer, an outer resin layer, and a metal layer located between the inner layer and the outer resin layer, wherein the inner layer contains an ethylenically unsaturated group, and a lithium secondary battery including the pouch exterior material.

Abstract: A cell system includes: a stacked-type cell module (100) having a plurality of lithium ion unit cells (1) being stacked and having through holes (3a, 3b) formed therein; a gas supply part (31); a cooling liquid supply part (32); a temperature sensor (35); and a control part (36) that controls switching between a normal control mode and a high-temperature control mode based on a signal from the temperature sensor (35). In the normal control mode, the control part (36) controls the gas supply part (31) to supply a gas to the through holes (3a, 3b), and at the same time, controls the cooling liquid supply part (32) to stop supply of a cooling liquid, and in the high-temperature control mode, the control part (36) controls the cooling liquid supply part (32) to supply the cooling liquid to the through holes (3a, 3b) to which the gas is supplied, and at the same time, controls the gas supply part (31) to stop supply of the gas.

Abstract: The disclosure provides a separator comprising a porous substrate and a heat-resistant layer disposed on a surface of the substrate. The heat-resistant layer comprises a binder and a plurality of inorganic particles, wherein the heat-resistant layer is disposed on the surface of the porous substrate in the range of 10% to 90% of the total surface area of the porous substrate.

Abstract: Methods for manufacturing a pouch-type battery cell include disposing one or more electrode pairs between a first aluminum pouch layer and a second aluminum pouch layer, sealing the first pouch layer and the second pouch layer to form a peripheral seal joining the first pouch layer and the second pouch layer to form a pouch with an outer edge encasing the anode and the cathode, applying a photocatalytic polymer coating precursor to the outer edge of the pouch, and photo-curing the photocatalytic polymer coating precursor to form a conformal edge coating. The photocatalytic polymer coating precursor includes one or more photo-initiators, one or more acrylates, and one or more polyamines. The polyamines can include tertiary amines including ?-CH functional groups, diamines represented by the formula H2N—R—NH2, wherein R represents saturated and unsaturated aliphatic moieties, and N,N?-(2,2-dimethylpropylidene) hexamethylenediamine.

Abstract: Provided is a bipolar lead-acid battery relating to the technical filed of battery. The bipolar lead-acid battery includes a housing with a battery cavity inside and a plurality of single cells provided in the battery cavity, each of the single cells has an inner cavity for electrolyte injection, and the inner cavity of each single cell is independent of one another, and the housing has a plurality of air-distributing chambers communicating with the inner cavity of the each of the single cells in one-to-one correspondence above the battery cavity, wherein the housing further has a common pressure chamber, the air-distributing chambers communicate with the common pressure chamber through vents, respectively. The bipolar lead-acid battery has the advantages that it can be successfully manufactured and can be used normally, and solves the problems of short service life and unsuccessful manufacture of the existing battery.

Abstract: Disclosed are a method of manufacturing a polyethylene membrane comprising: stretching a polyethylene film in a first direction during a first stretching; attaching a plurality of rods on side edges of the polyethylene film; attaching a tape on the polyethylene film; stretching the polyethylene film having the rods attached thereto in a second direction during a second stretching; and annealing the polyethylene film after the second stretching. The second direction can be a transverse direction of the first direction, and the first stretching and the second stretching can be performed at the same (or higher) temperature and the same stretching speed as each other.

Abstract: The present disclosure relates generally to an electrode produced with a non-toxic solvent, resulting in a homogeneous mixture with uniform distributions of a conductive additive and a binder. Electrodes produced according to the present disclosure feature narrow binder particle size distribution, which distinguishes such electrodes from typical electrodes produced via a N-Methyl-Pyrrolidone (NMP) process. The resulting microstructure promotes the flow of current through the electrode and has an improved cycling stability due, in part, to the binder's and the conductive additive's ability to bind with the active material particles used in the fabrication of the electrode.

Abstract: Systems, methods, and apparatuses for increasing liquid absorption are described. Some embodiments may include a dressing having an absorbent layer containing super-absorbent material as well as ionic-exchange media (IEM). In some embodiments, the absorbent layer may include absorbent fibers. The absorbent fibers may each include a super-absorbent core surrounded by a water-permeable layer onto which ionic-exchange media (IEM) may be grafted. As liquid comes into contact with the IEM, its ionic nature may be reduced, therefore protecting the absorbent qualities of the super-absorbent material.

Abstract: The present invention belongs to the technical fields of macromolecular materials and batteries, and particularly relates to a non-porous separator and the use thereof, more particularly to a non-porous separator having a gelation function and the use thereof. This non-porous separator is composed of two or more macromolecular materials, wherein at least one of the macromolecular materials can be gelled by an organic solvent. This non-porous separator can be used in batteries having an organic solvent-based electrolyte and a high energy density, such that not only can a micro-short circuit, generated due to the introduction of foreign matters such as metals, be prevented, leading to an improved qualification rate for the product, but also the safety performance and the cycle life of such a battery can be improved significantly.

Abstract: The present invention relates to a new lithium ion battery separator and a manufacturing method therefor, composite fine-denier POY fibers with polypropylene PP acting as a core and alkali-soluble polyester COPET and polyethylene PE acting as a skin are produced by means of a chemical fiber composite spinning technology, wherein the COPET and PE are distributed as an islands-in-the-sea form, then the POY fibers are arranged as a fabric with a certain breadth by means of beam-warping, the fabric is subjected to stretching and hot-pressing by a hot roll such that the PE component having a low melting point is melted and joined to form a film, and then the COPET is dissolved away by means of an alkali solution such that a place where the COPET is present in the film become pores and PP fibers become the skeleton of the film, thus forming a lithium ion battery separator.

Abstract: A polyolefin porous separator includes a first surface and a second surface corresponding to the first surface. The surfaces of the polyolefin porous separator contain dendritic crystals and micropores, the dendritic crystals intersect with the micropores on the first surface or/and the second surface, and the dendritic crystals penetrate through the second surface from the first surface. A preparation method of the polyolefin porous separator includes: (1) a mixed melting of polyethylene resin and a mineral oil; (2) an extrusion of the mineral oil/polyethylene resin molten mixture; (3) a stretching of a thick sheet in a machine direction (MD); (4) a stretching of the separator in a transverse direction (TD); (5) immersing the separator into a solvent to extract the mineral oil; (6) a secondary stretching of the separator in the TD; and (7) subjecting the separator having the longitudinal crystals to a heat-setting treatment and then rolling up.

Abstract: The present invention provides a synthetic resin microporous film which has excellent permeability of lithium ions, can constitute high performance power storage devices, and is less likely to cause a short circuit between a positive electrode and a negative electrode as well as rapid decrease in discharge capacity due to a dendrite even when used in high power applications.

Abstract: In at least one embodiment, a separator is provided with a fibrous mat for retaining the active material on an electrode of a lead-acid battery. New or improved mats, separators, batteries, methods, and/or systems are also disclosed, shown, claimed, and/or provided. For example, in at least one possibly preferred embodiment, a composite separator is provided with a fibrous mat for retaining the active material on an electrode of a lead-acid battery. In at least one possibly particularly preferred embodiment, a PE membrane separator is provided with at least one fibrous mat for retaining the active material on an electrode of a lead-acid battery. In accordance with at least certain embodiments, aspects and/or objects, the present invention, application, or disclosure may provide solutions, new products, improved products, new methods, and/or improved methods, and/or may address issues, needs, and/or problems of PAM shedding.

Abstract: The present invention has an object to provide (i) a nonaqueous electrolyte secondary battery separator having excellent ion permeability and (ii) an insulating porous layer by which to achieve the nonaqueous electrolyte secondary battery separator. The insulating porous layer is a nonaqueous electrolyte secondary battery insulating porous layer containing: a resin A; and a resin B, the resin A and the resin B having therebetween a Hansen solubility parameter distance (HSP distance) (Ra) of not more than 10 MPa1/2.

Abstract: Electrochemical device (e.g., a capacitive device, a battery, or hybrid device) comprising a configuration of layers comprising at least one combination, wherein each combination comprises a porous particulate separator layer disposed between a first porous electrode layer and a second porous electrode layer, and optionally at least one particulate current collector layer, and a liquid electrolyte, wherein all the combinations, optional particulate current collector layers, and liquid electrolyte are encased in a package, and wherein essentially all the liquid electrolyte is confined within the configuration of layers. Capacitive electrochemical device comprising a first combination comprising a porous particulate separator layer disposed between a first porous electrode layer and a second porous electrode layer, optionally at least one particulate current collector layer, and a liquid electrolyte.

Abstract: A rechargeable lithium battery and a method of preparing the same are described. The rechargeable lithium battery includes a positive electrode including a positive active material; a negative electrode including a negative active material; and a liquid electrolyte including a lithium salt and a non-aqueous organic solvent. A separator is interposed between the negative electrode and positive electrode and includes a support. A fluoro-based polymer layer is positioned on both sides of the support. The positive electrode includes the positive active material in an amount from about 30 to about 70 mg/cm2.

Abstract: As a laminated porous film realizing excellent handling properties in a low-humidity environment, a laminated porous film in which a layer containing a polymer is laminated on at least one side of a polyolefin porous film, satisfying the following (1) and (2) is provided. (1) When the laminated porous film has left still for 1 hour in an environment at a temperature of 23° C. and a humidity of 50%, a lifting amount of the side parallel with the direction perpendicular to the machine direction is 8 mm or more. (2) When the laminated porous film has left still for 1 hour in an environment at a temperature of 23° C. and a humidity of 5%, a lifting amount of the side parallel with the machine direction is 15 mm or less.

Abstract: A process for polymerizing propylene in the presence of a polymerization catalyst by polymerizing propylene with a comonomer selected from the group of ethylene and C4-C10 alpha-olefins in two polymerization stages where the comonomer is present in at least one of the polymerization stages. The first polymerization stage is conducted in a loop reactor and the second polymerization stage in a gas phase reactor. The polymer produced in first polymerization stage has a higher melt flow rate and a lower content of comonomer units than the final polymer mixture. The process can be operated with a high throughput and catalyst productivity. The polymers are useful for making films.

Abstract: Provided is a nonaqueous electrolyte secondary battery separator that has (i) an excellent ion permeability and (ii) reduced occurrence of a leak defect despite a small thickness. The nonaqueous electrolyte secondary battery separator includes a porous film containing polyolefin as a main component, the nonaqueous electrolyte secondary battery separator having a Gurley value within a range of 50 sec/100 cc to 200 sec/100 cc, the nonaqueous electrolyte secondary battery separator having a thickness within a range of 3 ?m to 16 ?m, the nonaqueous electrolyte secondary battery separator satisfying 0.85?((SMD/Sm)+(STD/Sm))/2?0.91.

Abstract: A polyolefin microporous membrane includes a polyethylene composition, and 0.5% or more but less than 5% by mass of polypropylene, wherein the polyethylene composition includes polyethylene having a mass average molecular weight of 2.5×105 to 5×105 and ultrahigh molecular weight polyethylene having a mass average molecular weight of 1×106 to 3×106 in an amount of more than 5% by mass and not more than 50% by mass based on 100% by mass of polyethylene composition and has a molecular weight distribution (Mw/Mn) of 5.0 to 300, and the polyolefin microporous membrane has an injection of electrolyte of 20 seconds or less and a uniform polypropylene distribution in at least one plane perpendicular to the thickness direction.

Abstract: A multilayer porous membrane comprising a porous membrane containing a polyolefin resin as a main component; and a porous layer containing an inorganic filler and a resin binder and laminated on at least one surface of the porous membrane; wherein the porous membrane has an average pore size d=0.035 to 0.060 ?m, a tortuosity ?a=1.1 to 1.7, and the number B of pores=100 to 500 pores/?m2, which are calculated by a gas-liquid method, and the porous membrane has a membrane thickness L=5 to 22 ?m.

Abstract: The invention relates to a thermoplastic polymer-based battery separator, which contains a compound of formula R (OR1)n(COOMx+1/x)m. In said formula, R represents a non-aromatic hydrocarbon group comprising between 10 and 4,200 carbon atoms, which can be interrupted by oxygen atoms, R1 represents H, —(CH2)kCOOMx+1/x or —(CH2)k—SO3Mx+1/x, whereby k stands for 1 or 2, M represents an alkali or earth alkaline metal ion, H+ or NH4+, whereby not all variables of M are defined simultaneously as H+, n stands for 0 or 1, m stands for 0 or a whole number from 10 to 1,400 and x stands for 1 or 2. The ratio of oxygen atoms to carbon atoms in the compound according to the aforementioned formula ranges between 1:1.5 and 1:30 and n and m cannot simultaneously represent zero.

Abstract: There is provided a secondary battery including a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode, wherein at least one of the positive electrode and the negative electrode contains a granular solid electrolyte and a granular conduction aid both bonded to a surface of a granular electrode active substance.

Abstract: The present invention provides a polyolefin microporous membrane made of a polyolefin resin and an inorganic particle, and the puncture strength of the microporous membrane is 3 N/20 ?m or more and the membrane thickness retention ratio in penetration creep is 16% or more, thereby being excellent in safety and long-term reliability, and a separator for a nonaqueous electrolyte battery, and the like can be provided.

Abstract: A battery includes a flat wound electrode body formed by winding a positive electrode sheet and a negative electrode sheet with a separator interposed therebetween into a flat shape. The separator has an outer edge adjacent portion adjacent to either an outer edge of a positive electrode active material layer or an outer edge of a negative electrode active material layer. In a curve positioned portion disposed at least in a curved portion of the flat wound electrode body, the outer edge adjacent portion has a suppression portion for suppressing the occurrence or development of a crack.

Abstract: Disclosed is a secondary battery having a structure in which a jelly-roll having a cathode/separator/anode structure is mounted in a cylindrical battery case, wherein a plate-shaped insulator mounted on the top of the jelly-roll includes a molded article made of a polymer resin or a polymer composite and a plurality of fine pores is perforated through the molded article.

Abstract: A non-aqueous electrolyte battery in which formation of a flame retardant layer formed on the surface of an electrode or the like hardly affects the discharge characteristics is provided. A non-aqueous electrolyte battery 1 includes a positive electrode 3, a negative electrode 5, and a separator 7. A porous layer having ion permeability is formed using a flame retardant material on a surface of the positive electrode 3. The porous layer is formed by applying a hot melt, which is a fused flame retardant material made of a thermoplastic resin, to the surface of the positive electrode 3.

Abstract: A coating liquid according to the present invention comprises polyvinyl alcohol (PVA), boric acid and/or an organometallic compound having the ability of cross-linking PVA, an inorganic filler, a water-soluble compound having a carboxyl group and/or a sulfonic group, and water. According to the present invention, a coating liquid can be obtained which is useful in the preparation of a laminated porous film having suppressed powder fall-off and excellent heat shape stability.

Abstract: This invention relates to low-cost, electroactive-polymer incorporated fine-fiber composite membranes for use as overcharge and/or overdischarge protection separators in non-aqueous electrochemical cells and the methods for making such membranes.

Abstract: A porous polymer separator for use in a lithium ion battery is formed by a temperature-induced phase separation method. The porous polymer separator includes a polymer matrix having opposed major faces and a network of pore openings that extends between the major faces and permits intrusion of a lithium-ion conducting electrolyte solution. As part of the temperature-induced phase separation method, a single phase polymer solution that includes a polymer material dissolved in a miscible mixture of a real polymer solvent and a polymer non-solvent is prepared at an elevated temperature above room temperature. A film is then formed from the single phase polymer solution and cooled to phase-separate the polymer material into a solid polymer precipitate. Additional polymer non-solvent is then used to remove the real polymer solvent from the solid polymer precipitate followed by drying.

Abstract: A separator includes a non-woven fabric substrate having pores, fine thermoplastic powder located inside the pores of the non-woven fabric substrate, and a porous coating layer disposed on at least one surface of the non-woven fabric substrate. The fine thermoplastic powder has an average diameter smaller than that of the pores and a melting point lower than the melting or decomposition point of the non-woven fabric substrate. The porous coating layer includes a mixture of inorganic particles and a binder polymer whose melting point is higher than the melting or decomposition point of the fine thermoplastic powder. In the porous coating layer, the inorganic particles are fixedly connected to each other by the binder polymer and the pores are formed by interstitial volumes between the inorganic particles. Previous filling of the large pores of the non-woven fabric substrate with the fine thermoplastic powder makes the porous coating layer uniform.

Abstract: The present invention relates to microporous membranes comprising polymer and having well-balanced permeability and heat shrinkage, especially heat shrinkage at elevated temperature. The invention also relates to methods for making such membranes, and the use of such membranes as battery separator film in, e.g., lithium ion secondary batteries.

Abstract: The invention relates to a perforated polymer film with porosity P from 30% to 50% and with an arrangement of perforations which is characterized by the perforation shape, the ratio of the semiaxes of the perforations, the orientation of the perforations, and the regular arrangement of the perforations, where the longitudinal tensile stress that the polymer film withstands without breaking is greater than that for identical porosity and any other arrangement of perforations which differs in at least one feature.

Abstract: A base material for a lithium ion secondary battery separator provided by the present invention comprises a polyethylene terephthalate fiber, in which an average fiber diameter of the polyethylene terephthalate fiber is 9.0 ?m or less, a specific X-ray diffraction intensity derived from the polyethylene terephthalate fiber is 300 cps/(g/m2) or more, and a coefficient of variation of a specific X-ray diffraction intensity is 12.0% or less, and is excellent in the workability during production and excellent in mechanical strength, uniformity and handling in a subsequent treatment step.

Abstract: Disclosed is a porous nanoweb including first and second nanofilaments, which facilitates to perform heat resistance simultaneously with a shutdown function for preventing a battery explosion caused by an abnormal heat generation, and to realize small thickness and easy control of porosity, wherein, if the porous nanoweb is used as a battery separator for a secondary battery, it allow the good battery efficiency and good safety owing to the low resistance, the porous nanoweb comprising the first nanofilament having a melting temperature not more than 200° C.; and the second nanofilament having a melting temperature not less than 210° C.

Abstract: Provided is a microporous separator for a lithium secondary battery having shutdown properties wherein the separator comprises a propylene random copolymer which has a melt index of 0.5-10 g/10 minutes and comprises one or more species of comonomers in the content of 0.1-8 wt %.

Abstract: A battery including an electrode assembly having a positive electrode, a negative electrode and a separator interposed between the electrodes, a container housing the electrode assembly, a tab attached to a first side of an uncoated region of the electrode assembly, the tab having a terminal, a first insulator interposed between the tab and a first inner surface of the container, and a cap assembly closing the container and having the terminal passing therethrough.

Abstract: A separator arranged between a pair of electrode sheets includes a nonwoven fabric formed of thermoplastic resin fibers spun by a melt-blowing process. The fibers include fine fibers having fiber diameters of 0.1 ?m or more and 1 ?m or less, and thick fibers having fiber diameters of 8 ?m or more and 30 ?m or less. The fine fibers and the thick fibers are mixed over the entire thickness of the nonwoven fabric.

Abstract: Provided is a method for producing a propylene-based resin microporous film capable of forming a high-performance lithium ion battery. The method for producing a propylene-based resin microporous film includes an extrusion step of melt-kneading a propylene-based resin in an extruder, and extruding the resin to obtain a propylene-based resin film; a first stretching step of uniaxially stretching the propylene-based resin film at a surface temperature of ?20 to 100° C.; second stretching step of repeating, a plurality of times, a stretching basic step in which the propylene-based resin film after the first stretching step is uniaxially stretched at a surface temperature that is equal to or lower than a temperature lower than the melting point of the propylene-based resin by 10 to 100° C.

Abstract: Disclosed is a method of manufacturing a porous separator including an elastic material, and a separator manufactured by the method. The separator includes an elastic material being uniformly dispersed in a polymer at a weight ratio of 40:60 to 5:95, and a value of elongation at break in a low tensile strength direction at room temperature is greater than or equal to 250%. In addition, the method of manufacturing a porous separator includes forming an extruded sheet by extruding a mixture of a polymer and an elastic material at a weight ratio of 95:5 to 60:40, forming a film by annealing and stretching the extruded sheet, and forming a porous separator by heat setting the stretched film. Accordingly, a thermal shrinkage ratio of the film is reduced and an elongation at break is greatly increased, to provide a porous separator with improved stability.

Abstract: The present invention provides a propylene-based resin microporous film which has excellent electrolyte solution retention property, and can provide a lithium ion battery in which a decrease in discharge capacity is highly reduced even after repeated charge and discharge. The propylene-based resin microporous film is a propylene-based resin microporous film having micropores, wherein a propylene-based resin having a weight average molecular weight of 250,000 to 500,000, a melting point of 160 to 170° C., and a pentad fraction of 96% or more is contained, the surface aperture ratio is 27 to 42%, the ratio of a surface aperture ratio to a porosity is 0.6 or less, and the degree of gas permeability is 50 to 400 s/100 mL.

Abstract: A method for bonding a porous flexible membrane to a rigid material is disclosed. In some embodiments, the method includes applying, at a bonding site of the porous membrane, a pre-treatment solvent solution, drying the bonding site of the porous membrane, applying, at a bonding site of the rigid structure, a first solvent that is capable of dissolving a surface of the rigid material, applying, at the bonding site of the porous membrane, a second solvent that is capable of dissolving the polymeric residue material dissolved in the pre-treatment solvent solution, and pressing the porous membrane to the rigid material at their respective bonding sites. In some embodiments, the pre-treatment solvent solution may include a solvent carrying dissolved polymeric residue material configured to fill the pores of the porous membrane at the bonding site of the porous membrane.

Abstract: An aromatic polyamide porous film has a total number of branch points of pores in an area of 3 cubic micrometers obtained by three-dimensional structural analysis is 2,000 to 20,000, which ensures high rate characteristics and is also capable of suppressing deterioration of cycle characteristics and storage characteristics as well as abnormal heat generation, when used as a separator for battery, and also has excellent heat resistance; and a separator for battery and a battery, each including the aromatic polyamide porous film.

Abstract: The present invention provides a coating liquid, a laminated porous film and a method for producing a laminated porous film. The coating liquid comprises a binder resin, a filler and a medium, wherein the filler is a mixture comprising (a) a filler having a specific surface area of not less than 7 m2/g and not more than 80 m2/g and (b) a filler having a specific surface area of not less than 3 m2/g and not more than 6 m2/g in a filler (a) to filler (b) weight ratio of from 5:95 to 40:60. The laminated porous film is a laminated porous film in which a heat-resistant layer is laminated on one or both of the surfaces of a porous film substrate, wherein the heat-resistant layer is a heat-resistant layer formed by removing the medium from the coating liquid.

Abstract: A highly proton conductive polymer electrolyte composite membrane for a fuel cell is provided. The composite membrane includes crosslinked polyvinylsulfonic acid. The composite membrane is produced by impregnating a mixed solution of vinylsulfonic acid as a monomer, a hydroxyl group-containing bisacrylamide as a crosslinking agent and a photoinitiator or thermal initiator into a microporous polymer support, polymerizing the monomer, and simultaneously thermal-crosslinking or photo-crosslinking the polymer to form a chemically crosslinked polymer electrolyte membrane which is also physically crosslinked with the porous support. Further provided is a method for producing the composite membrane in a simple manner at low cost as well as a fuel cell using the composite membrane.

Abstract: A non-aqueous electrolyte secondary battery comprising electrodes including a positive electrode and a negative electrode, a separator positioned between the electrodes, and a non-aqueous electrolyte, wherein the electrodes have a collector carrying an active substance material, and the collector of at least one of the positive electrode and the negative electrode is a three-dimensional structure formed of a resin fiber covered with a metal film.

Abstract: The invention relates to a membrane comprising a poly(dialkylene ester) thermoplastic polyurethane composition. The invention also provides an electrochemical cell comprising a positive electrode, a negative electrode, and (I) a separator membrane disposed between said positive and negative electrodes, wherein the said membrane comprises (A) the described poly(dialkylene ester) thermoplastic polyurethane composition.

Abstract: A microporous membrane is made by a dry-stretch process and has substantially round shaped pores and a ratio of machine direction tensile strength to transverse direction tensile strength in the range of 0.5 to 5.0. The method of making the foregoing microporous membrane includes the steps of: extruding a polymer into a nonporous precursor, and biaxially stretching the nonporous precursor, the biaxial stretching including a machine direction stretching and a transverse direction stretching, the transverse direction stretching including a simultaneous controlled machine direction relax.