Improved separators, batteries, systems, vehicles, and related methods

Abstract

To provide a separator enabling a battery to have a high charge speed and / or high charge capacity.SOLUTION: When a single-layer battery separator film has an aspect ratio of 1.0 MD / TD pore, a sphericity ratio of a three-dimensional pore between 1.0 and 2.0, a hole with an average pore diameter range between 0.09 and 0.99 μm, a ratio of tensile strength in an MD direction with respect to tensile strength in a TD direction between 1.4 and 1.6, a porosity range between 50% and 80%, a thickness range between 15 and 20 μm, tensile strength in the TD direction between 500 kg / cm2 and 700 kg / cm2, tensile strength in the MD direction between 700 kg / cm2 and 950 kg / cm2, a Gurley value between 28 and 65 seconds, and a shrinkage factor in the TD direction when heated for one hour at 90°C of 0.1% or 0.2%, and is used for a recharged battery, the recharged battery includes a microporous polypropylene dry-stretched film indicating a charge capacity of at least 108.64 mAh / g.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This patent application claims priority to and the benefit of U.S. Patent Application Serial No. 15 / 009,888, filed January 29, 2016, which is hereby incorporated by reference in its entirety.

[0002] In at least selected embodiments, the present invention or application relates to new or improved battery separators, base films or membranes, batteries, cells, devices, systems, and / or vehicles, and / or the like, and / or methods of making or using such separators, films or membranes, batteries, cells, devices, systems, and / or vehicles, and / or the like. In at least certain embodiments, the present invention or application relates to biaxially oriented porous membranes, composites including biaxially oriented porous membranes, biaxially oriented microporous membranes, biaxially oriented macroporous membranes, battery separators, flat sheet membranes, and / or liquid bearing media having improved charge capacity, and / or related methods, methods of manufacture, methods of use, and / or the like. In accordance with at least certain selected embodiments, a potentially preferred inventive dry-laid separator may be biaxially oriented and have a preferred thickness in the range of 10 μm to 25 μm, with improved strength, high porosity, and unexpectedly and / or surprisingly high charge capacity, e.g., high 10 C rate charge capacity.

[0003] Additionally, the high charge capacity and high porosity of possibly preferred inventive separators or membranes may provide excellent charge rate and / or charge capacity performance in rechargeable and / or secondary lithium batteries, such as lithium ion batteries, for high power and / or high energy applications, such as, by way of example only, electrically powered vehicles, or hybrid electric vehicles. According to at least certain embodiments, the present invention relates to improved microporous battery separators for secondary lithium batteries, improved microporous battery separators having increased or high charge rate and / or increased or high charge capacity in or for secondary lithium batteries, and / or related methods of manufacture, methods of use, and / or the like. [Background technology]

[0004] Porous membranes can be produced by a variety of methods. Several methods are known and can have a significant effect on the characteristics that the resulting membrane will possess. See, for example, Kesting, Robert E., Synthetic Polymeric Membranes, A Structural Perspective, Second Edition, John Wiley and Sons, New York, NY, (1985). To produce porous polymer membranes, Three well-known methods include dry stretching (also called the dry process and / or the CELGARD® process), the wet process, and the particle stretching process.

[0005] The dry process involves at least three steps: extrusion, annealing, and stretching. Pores are formed during stretching of the extruded stretched precursor. This stretching is in one direction, i.e., the machine direction (MD). See, for example, pages 290-297 of Kesting, Ibid., incorporated herein by reference. The wet process, also known as phase inversion (or phase inversion), involves the formation of a polymer resin. The wet process involves mixing the polymer with processing oils or plasticizers and / or other additives, the mixture is then extruded, and the processing oils or plasticizers are removed. During the wet process, pores are formed when the processing oils are removed. See, for example, Kesting, Ibid., pages 237-286, incorporated herein. In the particle stretching process, the polymer material is mixed with particles and the mixture is extruded. Pores form during stretching when the interface between the polymer and the particles is broken by the stretching force. See, for example, U.S. Patent Nos. 6,057,061 and 6,080,507, which are incorporated herein by reference.

[0006] Each of these processes is unique and distinctive, resulting in physically different and distinguishable membranes. Distinguishing characteristics can include pore shape and size. For example, membranes derived from dry processes may have slit-like pores due to machine direction stretching, while membranes derived from certain wet processes may have rounded pores that sometimes have a lacy appearance due to plasticizers. Finally, particle-stretched membranes may have pores that appear more elliptical. In each of these processes, mechanical strength is characterized in terms of machine direction (MD) and transverse direction (TD) tensile strength. U.S. Patent No. 8,795,565 describes stretching dry-processed membranes along both the MD and TD axes. Biaxially stretched membranes can improve mechanical strength, which can influence the membrane's strength profile in a battery. Furthermore, it has been shown to be advantageous to obtain membranes with a balanced MD-to-TD strength ratio. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent No. 6,057,061 [Patent Document 2] U.S. Patent No. 6,080,507 [Patent Document 3] U.S. Patent No. 8,795,565 Summary of the Invention [Problem to be solved by the invention]

[0008] Batteries used in high-power and / or high-energy applications, such as those used in electric drive vehicles (EDVs), may require separators that enable the battery to have high charge rates and / or high charge capacities for optimal high-energy performance. While rechargeable lithium-ion batteries have been shown to be commercially viable for at least some such high-power and / or high-energy applications, there is a continuing need for improvements in energy storage, power, and life cycle capabilities, particularly in the area of ​​separators that enable batteries to have unexpectedly high charge rates and / or high charge capacities. Furthermore, there is a continuing need for improved microporous battery separators or membranes that meet the high-energy performance demands of the electric drive vehicle and hybrid vehicle battery markets, as well as more complex consumer electronics systems. [Means for solving the problem]

[0009] According to at least selected embodiments, the present invention or application can address the above-mentioned needs and / or relate to new or improved battery separators, base films or membranes, batteries, cells, devices, systems and / or vehicles, methods of making and / or using such separators, films or membranes, batteries, cells, devices, systems and / or vehicles, etc. According to at least certain embodiments, the present invention or application relates to biaxially oriented porous membranes, composites comprising biaxially oriented porous membranes, biaxially oriented macroporous membranes, battery separators, flat sheet membranes, and / or liquid retention media having improved charge capacity, and / or related methods, and / or methods of making, using, etc.

[0010] According to at least certain selected embodiments, the possibly preferred dry-process separators of the present invention may be biaxially oriented and may have a preferred thickness range of 10 μm to 25 μm, with improved strength, porosity, and unexpectedly and / or surprisingly high charge capacities, e.g., high charge capacities at 10 C rates. Furthermore, the high charge capacities and high porosity of the separators or membranes of the present invention may be useful in, for example, charging batteries, such as lithium-ion batteries, for high power and / or high energy applications, such as electric drive vehicles or hybrid electric vehicles. The present invention may provide excellent charge rate and / or charge capacity performance in rechargeable and / or secondary lithium batteries.

[0011] According to at least certain embodiments, the present invention relates to improved microporous battery separators for secondary lithium batteries, improved microporous battery separators having increased or high charge rates and / or increased or high charge capacities in or for secondary lithium batteries, and / or related methods of manufacture, methods of use, and / or the like. According to at least certain selected embodiments, the present invention relates to primary or secondary lithium batteries, high charge and / or discharge rate batteries, high charge and / or discharge rate batteries for drones, racing cars, fast-charging buses, electric vehicles, hybrid electric vehicles, and / or other vehicles or devices requiring high charge and / or discharge rate batteries, high charge and / or discharge rate primary or secondary lithium batteries, high charge and / or discharge rate primary lithium batteries, and / or high charge and / or discharge rate secondary lithium batteries, and / or related methods, and / or combinations thereof.

[0012] According to at least certain selected embodiments, aspects, or objects, the present invention or application may address the above-mentioned needs and / or relate to new or improved battery separators, base films, or membranes, and / or methods of making and / or using such separators, films, or membranes. According to at least certain selected embodiments, the present invention or application relates to biaxially stretched porous membranes, composites comprising biaxially stretched porous membranes, biaxially stretched microporous membranes, biaxially stretched macroporous membranes, battery separators, flat sheet membranes, or liquid (or electrolyte) retention media having improved charge capacity, and / or related methods, and / or methods of making, using, etc.

[0013] A possibly preferred inventive dry-process separator may be biaxially stretched and may have a membrane or separator thickness ranging from about 5 μm to 50 μm, preferably 10 μm to 25 μm, with improved strength, porosity, and unexpectedly or surprisingly high charge capacity, e.g., high charge capacity at a 10 C rate. Furthermore, the high charge rate and / or high charge capacity and high porosity of the separators or membranes of the present invention may provide excellent charge rate performance in rechargeable lithium batteries for high-power and / or high-energy applications, such as electric drive vehicles or hybrid electric vehicles. Furthermore, the present invention relates to various methods for increasing the C-rate of lithium secondary batteries, as well as various improved batteries, such as hybrid batteries, including batteries for hybrid electric vehicles, having separators that enable such batteries to have unexpectedly or surprisingly high C-rates. These and other features of the present invention are described herein.

[0014] According to at least some embodiments, aspects, or objects, the present invention or application can address the above-mentioned needs and / or relates to new or improved battery separators, base films or membranes, and / or methods of making and / or using such separators, films or membranes, particularly for batteries used in high power and / or high energy applications, such as electric drive vehicles (EDVs), and / or for batteries having high energy performance and / or optimization of energy storage, power, and life capabilities, and / or unexpectedly high charge rates and / or high charge capacities, requiring separators that enable batteries to have high charge rates and / or high charge capacities, and relates to new or improved microporous battery separators or membranes, coated separators or membranes, composite separators or membranes, and / or the like, that meet the high energy performance requirements of the electric drive vehicle battery market and hybrid automobile battery market, as well as more complex consumer electronics systems, drone batteries, race car batteries, fast charging systems, fast charging buses, and the like.

[0015] A novel, potentially preferred porous battery separator has been developed for use in lithium-ion secondary batteries. A potentially preferred separator membrane, separator, base film, or membrane of the present invention is a microporous, mesoporous, or macroporous wet- or dry-process polymer monolayer, multilayer, or multi-layer membrane or separator, perhaps more preferably a microporous dry-process polyolefin monolayer, multilayer, or multi-layer membrane or separator, perhaps most preferably a dry-process microporous polypropylene monolayer. The polypropylene separator of the present invention can be prepared by a dry process (e.g., the CELGARD® dry process), and the separator or membrane can be uncoated, coated, treated, laminated to one or more other layers or materials (e.g., glass or PP nonwoven materials or layers), and / or the like.

[0016] Preferred membranes of the present invention when used in batteries, combining balanced MD / TD strength, high porosity and high C-rate and / or charge capacity, have improved cycle life performance and / or greater safety in lithium or lithium-ion secondary batteries for use in high power end applications.

[0017] Exemplary membranes of the present invention, having a preferred thickness range of 10 μm to 25 μm, have high charge rates and / or high charge capacities and superior discharge performance compared to known battery separator membranes. The separator should have high mechanical strength to withstand the rigors of cell assembly and continuous charge-discharge cycling throughout the battery's lifespan. Separators of the present invention preferably have a puncture strength of greater than 100 gf, more preferably greater than 200 gf, and perhaps most preferably greater than 300 gf. In one specific example, separators of the present invention have a puncture strength ranging from 335 gf at a thickness of about 14 μm to 400 gf at a thickness of about 20 μm. The dry-process microporous battery separator membranes of the present invention preferably have separator charge and / or discharge performance, charge acceptance characteristics, and / or cycle life performance in lithium-ion secondary batteries comparable to or superior to wet-process microporous battery separator membranes.

[0018] and / or methods of making and / or using such separators, films or membranes, batteries, systems, vehicles, and / or methods of increasing battery or cell charge rate, charge capacity, and / or discharge rate, and / or methods of improving batteries, systems including such batteries, systems, and / or the like; biaxially stretched porous membranes, composites including biaxially stretched porous membranes, biaxially stretched microporous membranes, biaxially stretched macroporous membranes, battery separators with improved loading capacity, and related methods, and methods of making, using, and the like; flat sheet membranes, liquid holding media; dry process separators; biaxially stretched separators; dry process biaxially stretched separators having improved high strength, high porosity, and unexpectedly and / or surprisingly high loading capacity, e.g., high 10C rate charge capacity, and / or methods of improving batteries, systems including such batteries, systems, and / or the like; separators or membranes having high charge capacity, and high porosity, excellent charge rate and / or high charge capacity performance in rechargeable and / or secondary lithium batteries, such as lithium ion batteries, for high power and / or high energy applications, batteries, devices and / or vehicles, and / or the like; single or multi-layer separators, monolayer separators, trilayer separators, composite separators, laminated separators, co-extruded separators, coated separators, 1C or higher separators, 1C separators in at least certain selected embodiments, batteries, cells, systems, devices, vehicles, and / or the like; improved microporous battery separators for secondary lithium batteries, improved microporous battery separators for or in secondary lithium batteries with increased or high charge (C) rates, discharge (C) rates and / or increased or high charge capacity, and / or related methods of manufacture, use, etc., and / or combinations thereof. The matching information will be disclosed or provided.

[0019] Certain embodiments may be generally related to U.S. Patent No. 8,795,565 B2, issued August 5, 2014, and / or U.S. Patent Application Publication No. 2011 / 0223486, published September 15, 2011, both of which are incorporated by reference herein in their entireties. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a 20,000x SEM (scanning electron microscope) surface image of the biaxially stretched separator of Example 1 (EX1). [Figure 2] FIG. 2 is an SEM surface image at 20,000 magnifications of Comparative Example 1 (CE1). [Figure 3] Figure 3 shows the discharge performance of Examples 1 and 2 compared to Comparative Examples 1 and 2. Comparative Example 1 is a 25 μm thick microporous, dry-process monolayer polypropylene (PP) membrane that is MD-stretched only (no TD stretching). Comparative Example 2 is a 16 μm thick microporous, dry-process microporous polypropylene (PP) membrane that is MD-stretched only (no TD stretching). [Figure 4] FIG. 4 illustrates the better C-rate performance of Example 1 (EX1) and Example 2 (EX2) compared to Comparative Example 1 (CE1) and Comparative Example 2 (CE2). [Figure 5] Figure 5 shows the C-rate performance of Example 1 (EX1) compared to Comparative Example 3 (CE3), which is a microporous, dry-laid, 16 μm thick, monolayer polypropylene (PP) membrane that is MD-stretched only (no TD stretching). DETAILED DESCRIPTION OF THE INVENTION

[0021] Exemplary new or improved microporous battery separators have been developed for use in lithium batteries, such as lithium-ion secondary batteries. In selected embodiments, a potentially preferred inventive separator membrane is a dry-process polypropylene monolayer porous battery separator. In certain embodiments, the separator is made of homopolymer polypropylene, optionally with a melt flow index of 0.7 to 0.8.

[0022] The membranes of the present invention are preferably produced by the dry stretching method (also known as the CELGARD® method). The dry stretching method refers to a method in which a non-porous precursor is stretched. See Kesting, R., Synthetic Polymeric Membranes, A Structural Perspective, Second Edition, John Wiley & Sons, New York, NY, (1985), pages 290-297, which is incorporated herein by reference. The dry stretching method, as described above, is a method in which a non-porous precursor is stretched. The particle stretching method is distinguished from the particle stretching method.

[0023] The membranes of the present invention can be distinguished from conventional biaxially stretched dry-stretched membranes because they exhibit significant improvements in several ways, including, but not limited to, superior high c-rate discharge performance, high c-rate charge performance, and / or exhibiting high capacity and / or longer cycle life at high c-rates.

[0024] With respect to discharge performance, the membrane of the present invention in at least one embodiment exhibits high rate discharge performance that is comparable to or better than Comparative Example 1 and Comparative Example 2 (see FIG. 3).

[0025] With respect to having high capacity at high C rates (see FIG. 4), the membranes of the present invention in at least one embodiment exhibit high capacity at both 5C and 10C, and at 10C, a significant, unexpected, and surprising improvement over Comparative Examples 1 and 2.

[0026] In certain embodiments, the membranes of the present invention can be further characterized as follows: Average pore size in the range of 0.090 to 0.099 microns (μm); porosity in the range of 50 to 80%; and / or 500 kg / cm 2 Greater transverse tensile strength. The above values ​​are exemplary values ​​and are not intended to be limiting, and therefore should be considered merely representative of certain current membrane embodiments.

[0027] The membrane of the present invention may be a single layer or a multi-layer. With respect to a multi-layer, the membrane may be a single layer of a multi-layer, or the membrane may be all layers of a multi-layer. If the membrane is less than all layers of a multi-layer, the multi-layer membrane may be produced by a lamination method. If the membrane is all layers of a multi-layer, the multi-layer may further be produced by a coextrusion process. Furthermore, the multi-layer may be produced from layers of the same or different materials.

[0028] The present membranes are preferably made by a dry-laid process in which the precursor membrane is biaxially oriented (i.e., stretched in the machine direction as well as the transverse direction). This process is described in more detail below. The present invention is not limited to the dry-laid or Celgard dry-laid processes.

[0029] Generally, the method for producing the above-mentioned membrane comprises extruding one or more polymers to form a non-porous precursor, and then biaxially stretching the non-porous precursor. Optionally, the non-porous precursor may be annealed before stretching. In one embodiment, the biaxial stretching comprises machine direction stretching and transverse direction stretching with simultaneous controlled machine direction relaxation. Machine direction stretching and transverse direction stretching may be simultaneous or sequential. In one embodiment, machine direction stretching is followed by transverse direction stretching with simultaneous machine direction relaxation. This process will be described in more detail below.

[0030] Extrusion generally follows the dry stretching method. The extruder can have a slot die (for flat precursors) or an annular die (for parison precursors). In the latter case, inflation parison technology (e.g., blow-up technology with a specific blow-up ratio (BUR)) can be employed. However, the birefringence of the non-porous precursor may not need to be as high as in conventional dry stretching methods. For example, in a conventional dry stretching method for producing a film with a porosity of >35% from polypropylene resin, the birefringence of the precursor is >0.0130, while in this process, the birefringence of the PP precursor can be as low as 0.0100. In another example, to produce a film with a porosity of >35% from polyethylene resin using a more conventional dry stretching method, the birefringence of the precursor is >0.0280, while in this process, the birefringence of the PE precursor can be as low as 0.0240.

[0031] In one embodiment, annealing (optional) can be performed at a temperature between Tm - 80°C and Tm - 10°C (where Tm is the melting temperature of the polymer). In another embodiment, it can be performed at a temperature between Tm - 50°C and Tm - 15°C. Some materials, such as materials with high crystallinity after extrusion, such as polybutene, do not require annealing.

[0032] Stretching in the machine direction can be carried out as cold stretching or hot stretching or both, and as a single step or multiple steps. In one embodiment, cold stretching can be carried out at <Tm - 50°C, and in another embodiment, at <Tm - 80°C. In one embodiment, hot stretching can be carried out at <Tm - 10°C. In one embodiment, the total machine direction stretching is in the range of 50 - 500%, and in another embodiment, in the range of 100 - 300%. During stretching in the machine direction, the precursor may contract laterally (conventional).

[0033] Transverse stretching includes simultaneously controlled machine direction relaxation. This means that as the precursor is stretched transversely, the precursor simultaneously contracts (i.e., relaxes) in the machine direction in a controlled manner. This means that the transverse stretching can be performed as a cold step, a hot step, or a combination of both. In one embodiment, the total transverse stretching can be in the range of 100 to 1200%, and in another embodiment, in the range of 200 to 900%. In one embodiment, the controlled machine direction relaxation is in the range of 5 to 80%, and in another embodiment, in the range of 15 to 65%. In one embodiment, the transverse stretching can be performed in multiple steps.

[0034] During transverse stretching, the precursor may or may not be allowed to shrink in the machine direction. In one embodiment of multi-step transverse stretching, the first transverse stretching step is a transverse stretch with controlled mechanical relaxation, followed by simultaneous transverse and longitudinal stretching, followed by transverse relaxation, and no machine direction stretch or relaxation.

[0035] If desired, the precursor after machine direction and transverse direction orientation may be subjected to heat setting, as is well known. The above membranes and processes are further described in the following non-limiting examples. [Example]

[0036] Example 1 Polypropylene (PP) resin is extruded using a 2.5-inch extruder. The extruder melt temperature is approximately 221°C. The polymer melt is fed into an annular die. The die temperature is set to approximately 220°C, and the polymer melt is cooled by blowing air through it. The extruded precursor has a thickness ranging from approximately 1 to 1.5 mils (mils), in some cases 1.2 to 1.4 mils, and in some cases approximately 27 μm. The extruded film is then annealed at approximately 150°C for approximately 2 minutes. The annealed film is then cold stretched to approximately 20% at room temperature, then hot stretched to approximately 228% and relaxed to approximately 32% at a temperature ranging from 150 to 160°C. The MD-stretched film is then stretched 450% in the transverse direction (TD) at a TD stretch temperature ranging from approximately 140 to 152°C, with a 50% MD relaxation. The finished film has a thickness of 15 μm and a porosity of 74%. TD tensile strength of finished film is 529Kg / cm 2 is.

[0037] Example 2 Polypropylene (PP) resin is extruded using a 2.5-inch extruder. The extruder melt temperature is approximately 221°C. The polymer melt is fed into an annular die. The die temperature is set to approximately 220°C, and the polymer melt is cooled by blowing air through it. The extruded precursor has a thickness ranging from approximately 1 to 1.5 mils, in some cases 1.2 to 1.4 mils, and in some cases approximately 27 μm. The extruded film is then annealed at approximately 150°C for approximately 2 minutes. The annealed film is then cold stretched to approximately 20% at room temperature, then hot stretched to approximately 228% and relaxed to approximately 32% at a temperature ranging from 160 to 170°C. The MD-stretched film is then stretched in the transverse direction (TD) to 450% at a TD stretch temperature ranging from approximately 150 to 160°C, with a 50% MD relaxation. The finished film has a thickness of 20 μm and a porosity of 69%. TD tensile strength of finished film is 650Kg / cm 2 is.

[0038] The properties of the films formed by Examples 1 and 2, as well as the properties of the film used as Comparative Example 1, are shown in Table 1.

[0039] [Table 1]

[0040] The separators described above as Examples 1 and 2, and Comparative Examples 1 and 2, were tested for charge capacity and C-rate, with the results shown in Table 2 below.

[0041] [Table 2]

[0042] Test Method Thickness Thickness is measured using an Emveco Microgage 210-A precision micrometer thickness gauge according to ASTM D374 test procedure. Thickness values ​​are reported in micrometers, μm.

[0043] Puncture strength Test samples are first preconditioned to 73.4°C and 50% relative humidity for a minimum of 20 minutes. An Instron Model 4442 is used to measure the puncture strength of the test samples. Thirty measurements are averaged across a 1.25" x 40" continuous specimen diagonally. The needle has a 0.5mm radius. The descent rate is 25mm / min. The film is held securely in a clamping device that utilizes an O-ring to tightly hold the test sample in place. The diameter of this clamped area is 25mm. The displacement (in mm) of the film punctured by the needle is recorded against the force (in grams of force) exerted by the tested film. The maximum force is the puncture strength in grams of force (gf). A load versus displacement plot is generated by this test method.

[0044] Pore ​​size Pore ​​size is measured using an Aquapore available through Porous Materials Inc. (PMI). Pore size is expressed in μm.

[0045] porosity The porosity of the microporous film samples was measured using ASTM method D-2873 and is defined as the percent void space in the microporous membrane.

[0046] TD and MD tensile strength Tensile strength along MD and TD is measured using an Instron Model 4201 according to ASTM D-882.

[0047] Heat shrinkage rate Shrinkage testing is measured by placing a 10 cm x 10 cm membrane sample in a manila holder and then hanging it in an oven using clips. Shrinkage is measured using calipers in the MD and TD directions before and after placing the test sample in an oven at 105°C for 1 hour. Shrinkage is also measured using calipers in the MD and TD directions before and after placing the test sample in an oven at 120°C for 1 hour. Shrinkage is expressed as MD shrinkage % and TD shrinkage % using a modified ASTM 2732.96.

[0048] Hot electrical resistance (ER) Hot electrical resistance is a measure of the resistance of a separator film under 50 pounds of pressure while the temperature is increased linearly at a rate of 60°C / minute. A 3 / 8" diameter piece of separator is saturated with electrolyte and sandwiched between two electrode disks made from either Al or Cu. The increase in resistance is measured as impedance and corresponds to the collapse of the pore structure due to melting or "shutdown" of the microporous separator membrane. If the microporous separator membrane sustains a high level of electrical resistance at elevated temperatures, this indicates that the separator membrane is capable of preventing shorting of the battery electrodes.

[0049] cycling All cycling was performed in constant current (CC) mode. The cathode used was 622NMC. The anode used was graphite. The electrolyte was 1M in 3:7 v:v EC:EMC solvent. LiPF6 salt was used. The voltage window was 3.0-4.3 V. Cycles 1-5 had a charge and discharge rate of C / 10. Cycles 6-10 had a charge and discharge rate of C / 5. Cycles 11-15 had a charge rate of C / 5 and a discharge rate of C / 2. Cycles 16-20 had a charge rate of C / 5 and a discharge rate of 1C (charge / discharge rate capacity; 1C is the full charge or discharge rate in 60 minutes). Cycles 21-25 had a charge rate of C / 5 and a discharge rate of 5C. Cycles 26-30 had a charge rate of C / 5 and a discharge rate of 10C. Cycles 31-35 had a charge and discharge rate of C / 10.

[0050] Other examples include primary or secondary batteries, including fast charge and / or discharge, drone batteries, race car batteries, bus batteries, electric vehicle batteries, hybrid vehicle batteries, etc. Some batteries are single-use primary fast charge and / or discharge lithium batteries. Other batteries are multi-use secondary fast charge and / or discharge lithium batteries. Preferred batteries may include fast charge lithium batteries, fast discharge lithium batteries, and / or fast charge and fast discharge lithium batteries.

[0051] According to at least selected embodiments, aspects and / or objectives, the present invention or application relates to new or improved battery separators, base films or membranes, batteries, systems, vehicles, and / or methods of making and / or using such separators, films or membranes, batteries, systems, and / or methods of increasing the charge rate, charge capacity, and / or discharge rate of batteries or cells, and / or methods of improving batteries, systems including such batteries, vehicles including such batteries, and / or systems, and / or the like; biaxially oriented porous membranes, composites including biaxially oriented porous membranes, biaxially stretched microporous membranes, biaxially stretched macroporous membranes, battery separators with improved charge capacity, and related methods and methods of making, using, and the like.

[0052] The present invention or application also relates to filtration media, humidity control media, flat sheet membranes, liquid retention media; dry process separators; biaxially oriented separators; improved strength, high porosity, and / or dry biaxially stretched separators having a thickness ranging from about 5 μm to 50 μm, preferably about 10 μm to 25 μm, with unexpectedly and / or surprisingly high charge capacities, such as high 10 C rate charge capacities; separators or membranes with high charge capacities and high porosity, excellent charge rate and / or charge capacity performance in rechargeable and / or secondary lithium batteries, such as lithium ion batteries, for high power and / or high energy applications, including, by way of example only, electric drive vehicles (EDVs) or hybrid electric vehicles (HEVs), electrified or electrically assisted vehicles, and regenerative Related to braking systems, idle start / stop systems (ISS), start / stop systems, electric vehicles (EV), battery electric vehicles (BEV), plug-in hybrid electric vehicles (PHEV), high charge or C-rate electric vehicle batteries, high charge or C-rate and high discharge or D-rate electric vehicle batteries, e-bike batteries, e-bicycle batteries, hybrid or multi-wheel drive electric vehicle batteries, home appliances, mobile devices, smartphones, laptops, tablets, polymer batteries, power cells, cordless tool batteries, cordless tools, and / or the like.

[0053] The present invention or application also relates to a single or multiple or multi-layer separator, a monolayer separator, a three-layer separator, a composite separator, a laminated separator, a co-extruded separator, a coated separator, a separator of 1 C or more (fully charging / discharging a battery or cell in 60 minutes or less), a separator of 2 C or more (fully charging / discharging a battery or cell in 30 minutes or less), a separator of 10 C or more (fully charging / discharging a battery or cell in 6 minutes or less), a separator of 20 C or more (fully charging / discharging a battery or cell in 3 minutes or less), a separator of at least 1 C, a separator of at least 2 C, a separator of at least 10 C, a separator of at least 20 C, a separator of more than 20 C, a separator of at least ... systems, equipment, vehicles, etc.; improved microporous battery separators for secondary lithium batteries, improved microporous battery separators having enhanced or high charge (C) rates, discharge (C) rates, and / or enhanced or high charge capacity for or in secondary lithium batteries, and / or related methods of manufacture, methods of use, etc. and / or combinations thereof.

[0054] In accordance with at least certain embodiments, the present invention or application relates to new or improved battery separators, base films or membranes, batteries, cells, devices, systems, vehicles, and / or methods of making and / or using such separators, films, membranes, batteries, cells, devices, systems, vehicles, etc. In accordance with at least certain selected embodiments, the present invention or application relates to biaxially oriented porous membranes, composites comprising biaxially oriented porous membranes, biaxially oriented microporous membranes, biaxially oriented macroporous membranes, battery separators, flat sheet membranes, or liquid retention media having improved charge capacity, and related methods and methods of making, using, etc.

[0055] Perhaps preferred, the dry-process separators of the present invention may be biaxially stretched and may have a thickness range of 10 μm to 25 μm, with improved strength, porosity, and unexpectedly and / or surprisingly high charge capacities, e.g., high 10 C rate charge capacities. Furthermore, the high charge capacity and high porosity of preferred separators or membranes of the present invention provide, by way of example only, superior charge rate and / or charge capacity performance in rechargeable and / or secondary lithium batteries, such as lithium-ion batteries for high-power and / or high-energy applications, such as electric drive vehicles or hybrid electric vehicles. According to at least certain selected embodiments, the present invention relates to improved microporous battery separators for secondary lithium batteries, improved microporous battery separators having increased or high charge rates and / or increased or high charge capacities in or for secondary lithium batteries, and / or related methods of manufacture, use, and the like.

[0056] In accordance with at least certain selected embodiments, the present invention or application relates to new or improved battery separators, base films or membranes, batteries, systems, vehicles, and / or methods of making and / or using such separators, films or membranes, batteries, systems, and / or methods of increasing battery or cell charge rate, charge capacity, and / or discharge rate, methods of improving batteries, systems including such batteries, vehicles including such batteries and / or systems, etc.; biaxially oriented porous membranes, composites including biaxially oriented porous membranes, biaxially oriented microporous membranes, biaxially oriented macroporous membranes, battery separators with improved charge capacity, and related methods, methods of making, methods of using, etc.

[0057] The present invention or application also relates to filtration media, humidity control media, flat sheet membranes, liquid retention media, dry process separators; biaxially oriented separators; dry process biaxially oriented separators having a thickness range of about 5 μm to 50 μm, preferably about 10 μm to 25 μm, with improved strength, high porosity, and unexpectedly and / or surprisingly high charge capacity, for example, high charge rate such as 10 C rate charge capacity; separators or membranes with high charge capacity and high porosity, charge rate and / or charge capacity performance for high power and / or high energy applications in rechargeable and / or secondary lithium batteries such as lithium ion batteries. , cells, devices, systems and / or vehicles, etc.; single or multiple, or multi-layer separators, monolayer separators, trilayer separators, composite separators, laminated separators, coextruded separators, coated separators, 1C or higher separators (separators that allow a battery or cell to be fully charged or discharged within 60 minutes), separators of at least 1C, batteries, systems, equipment, vehicles, etc.; improved microporous battery separators for secondary lithium batteries, improved separators having enhanced or high charge (C) rates, discharge (C) rates, and / or enhanced or high charge capacities in or for secondary lithium batteries. The present invention relates to an improved microporous battery separator, and / or related methods of manufacture, use, and / or the like, and / or combinations thereof.

[0058] Inventive separators according to at least some embodiments of the present invention may be particularly well-suited or adapted for use in regenerative braking systems or regenerative braking system batteries or cells in vehicles equipped with such systems, such as electric, hybrid, or electrified vehicles. Regenerative braking slows a vehicle by converting kinetic energy into electrical energy that can be stored in the battery or cell. In addition to improving the overall efficiency of the vehicle, the vehicle's electric drive, or the charging of the battery or cell, regenerative braking can extend the life of the braking system because its components do not heat up and wear out as quickly. Inventive separators according to the present invention may also be particularly well-suited or adapted for use in high-power and / or high-energy battery applications, such as, by way of example only, idle start-stop vehicles, electric drive vehicles, hybrid electric vehicles, power tools, cordless tools, energy storage systems, UPS, backup power systems, lead-acid and lithium battery systems, lithium battery and capacitor systems, and / or the like.

[0059] According to at least selected porous material or porous membrane embodiments of the present invention, the pores (openings) may have the following pore aspect ratios (based on the physical dimensions of the pore openings in the machine direction (MD) (length) and transverse machine direction (TD) (width)), as determined, for example, by measuring one or more pores (preferably several pores to ascertain an average) in an SEM of the surface, top, or front (A-side) of a selected membrane or composite, e.g., a monolayer, bilayer, or trilayer membrane: Typical: MD / TD aspect ratio range: 0.75 to 1.50 preferable: MD / TD aspect ratio range: 0.75 to 1.25 Most preferred: MD / TD aspect ratio range: 0.85 to 1.25

[0060] According to at least selected embodiments of the porous material or porous membrane of the present invention, when the MD / TD pore aspect ratio is 1.0, the three-dimensional or 3D pore sphericity coefficient or ratio (MD / TD / ND) ranges from 1.0 to 8.0 or more; perhaps preferably 1.0 to 2.5; and most perhaps preferably 1.0 to 2.0 or less (based on the physical dimensions of the pore opening in the machine direction (MD) (length), transverse machine direction (TD) (width), and thickness direction or cross-section (ND) (thickness)); for example, by measuring the MD and TD of one or more pores (preferably several pores to ascertain an average) in an SEM of the surface, top or front (A-side), or surface, bottom or back (B-side), and measuring the ND (the ND dimension may be for a pore different from the MD and TD dimensions, since it may be difficult to measure the ND, MD, and TD dimensions of the same pore) of one or more pores (preferably several pores to ascertain an average) in an SEM of the depth or height (C-side) (length or width cross-section or both).

[0061] According to at least selected porous material or membrane embodiments of the present invention, the pores (openings) may have the following pore aspect ratios (based on the physical dimensions of the pore openings in the machine direction (MD) (length) and transverse machine direction (TD) (width) based on measuring the pores in an SEM of the top or front (side A) of selected single-layer and triple-layer membranes): Typical values ​​for the machine direction MD (length) and transverse direction TD (width) aspect ratio ranges: MD / TD aspect ratio 0.75 to 1.50

[0062] According to at least selected embodiments of the porous material or porous membrane of the present invention, the pores ( The pore openings) may have the following three-dimensional or 3D sphericity coefficients or ratios (based on the physical dimensions of the pore openings in the machine direction, transverse machine direction (TD) (width), and thickness direction or cross-section (ND) (thickness)); for example, measuring one or more pores (preferably a few pores to ascertain an average) in an SEM of the surface, top or front (A-side), surface, bottom or back (B-side), and cross-section, depth or height (C-side) (length or width cross-section or both) of a selected membrane, layer, or composite, for example, of selected monolayer and trilayer membranes (since measuring the ND, MD, and TD dimensions can be difficult, the ND dimension may be a different pore than the MD and TD dimensions): for example, Typical: MD / TD aspect ratio in the range of 0.75 to 1.50 MD / ND dimension ratio is in the range of 0.5 to 7.50 TD / ND dimension ratio is in the range of 0.50 to 5.00 preferable: MD / TD aspect ratio range: 0.75 to 1.25 MD / ND dimension ratio is in the range of 1.0 to 2.50 TD / ND dimension ratio is in the range of 1.0 to 2.50 Most preferred: MD / TD aspect ratio range: 0.85 to 1.25 MD / ND dimension ratio is in the range of 1.0 to 2.0 ○TD / ND dimension ratio is in the range of 1.0 to 2.0

[0063] According to at least selected porous material or membrane embodiments of the present invention, the pores (openings) may have the following pore sphericity coefficients or ratios (based on the physical dimensions of the pore openings in the machine direction (MD) (length), transverse machine direction (TD) (width), and thickness direction or cross-section (ND) (thickness), based on measuring the pores in an SEM of the top or front (A-side) of the length and width of the cross-section (C-side) of selected monolayer and trilayer membranes): Machine direction MD (length), transverse direction TD (width), and Typical numbers for sphericity coefficient or ratio of thickness ND (vertical height): MD / TD aspect ratio in the range of 0.75 to 1.50 MD / ND dimension ratio is in the range of 0.50 to 7.50 TD / ND dimension ratio is in the range of 0.50 to 5.00

[0064] According to at least selected embodiments of the present invention, the microporous membrane is produced by a dry stretching process, resulting in substantially round pores and a ratio of machine direction tensile strength to transverse direction tensile strength of 0.5 to 6.0, preferably 0.5 to 5.0. The method for producing the microporous membrane includes extruding a polymer into a nonporous precursor and biaxially stretching the nonporous precursor, the biaxial stretching comprising machine direction stretching and transverse direction stretching, the transverse direction stretching comprising simultaneous controlled machine direction relaxation.

[0065] In accordance with at least selected embodiments of the present invention, the porous membrane is produced by the improved dry stretch process and has substantially round pores, a machine direction tensile strength to transverse direction tensile strength ratio of 0.5 to 6.0, a low Gurley and / or a low ER compared to conventional dry stretched membranes, and a larger and more uniform mean flow pore size, or both a low Gurley and a larger and more uniform mean flow pore size, compared to conventional dry stretched membranes.

[0066] According to at least selected embodiments of the porous material or porous membrane of the present invention, the pores (openings) have the following pore aspect ratios (as determined, for example, by measuring one or more pores (preferably several pores to ascertain an average) in an SEM of the surface, top or front (A-side) of a selected membrane or composite, e.g., a monolayer, bilayer or trilayer membrane): (based on the physical dimensions of the pore openings in the machine direction (MD) (length) and cross-machine direction (TD) (width): Typical MD / TD aspect ratio in the range of 0.75 to 1.50 preferable MD / TD aspect ratio range: 0.75 to 1.25 Most preferred MD / TD aspect ratio range: 0.85 to 1.25

[0067] According to at least selected embodiments of the porous material or porous membrane of the present invention, when the MD / TD pore aspect ratio is 1.0, the three-dimensional or 3D pore sphericity coefficient or ratio (MD / TD / ND) ranges from 1.0 to 8.0 or more; perhaps preferably 1.0 to 2.5; and most perhaps preferably 1.0 to 2.0 or less (based on the physical dimensions of the pore opening in the machine direction (MD) (length), transverse machine direction (TD) (width), and thickness direction or cross-section (ND) (thickness)); by measuring the MD and TD of one or more pores (preferably several pores to ascertain the average pore size) in an SEM of the top or front (A-side), or face, bottom or back (B-side) surface, and measuring the ND of one or more pores (preferably several pores to ascertain the average pore size) in an SEM of the depth or height (C-side) (length or width cross-section or both) (the ND dimension may differ from the MD and TD dimension, since it may be difficult to measure the ND, MD, and TD dimensions of the same pore).

[0068] According to at least selected porous material or porous membrane embodiments of the present invention, the sphericity coefficient or ratio of the three-dimensional or 3DMD / TD / ND pores ranges from 0.25 to 8.0 or greater than 8.0; perhaps preferably from 0.50 to 4.0; and most perhaps preferably from 1.0 to 2.0 or less than 2.0.

[0069] According to at least selected porous material or porous membrane embodiments of the present invention, the pores (openings) may have the following pore aspect ratios (based on the physical dimensions of the pore openings in the machine direction (MD) (length) and transverse machine direction (TD) (width) based on measuring the pores in an SEM of the top or front (side A) of selected single-layer and triple-layer membranes): Typical values ​​for the machine direction MD (length) and transverse direction (TD) (width) aspect ratio ranges are in the range of 0.75 to 1.50.

[0070] According to at least selected embodiments of the porous material or porous membrane of the present invention, the pores (openings) are characterized by the following three-dimensional or 3D sphericity coefficients or ratios (based on the physical dimensions of the pore opening in the machine direction (MD) (length), transverse machine direction (TD) (width), and thickness direction or cross-section (ND) (thickness)); for example, by measuring one or more pores (preferably several pores to ascertain an average) in an SEM of the top or front (A-side), face, bottom or back (B-side), and cross-section, e.g., depth or height (C-side) (length or width cross-section or both) of selected layers or composites of selected monolayer and trilayer membranes: (ND dimension may be different for pores than MD and TD dimension, since it may be difficult to measure ND, MD, and TD dimensions for the same pore): for example, Typical: MD / TD aspect ratio in the range of 0.75 to 1.50 MD / ND dimension ratio is in the range of 0.5 to 7.50 TD / ND dimension ratio is in the range of 0.50 to 5.00 preferable: MD / TD aspect ratio range: 0.75 to 1.25 MD / ND dimension ratio is in the range of 1.0 to 2.50 TD / ND dimension ratio is in the range of 1.0 to 2.50 Most preferred: MD / TD aspect ratio range: 0.85 to 1.25 MD / ND dimension ratio is in the range of 1.0 to 2.0 TD / ND dimension ratio is in the range of 1.0 to 2.0

[0071] According to at least selected porous material or porous membrane embodiments of the present invention, the pores (openings) may have the following pore sphericity coefficients or ratios (based on the physical dimensions of the pore openings in the machine direction (MD) (length), transverse machine direction (TD) (width), and thickness direction or cross-section (ND) (thickness), based on measuring the pores in an SEM of the top or front (A-side) of the length and width of the cross-section (C-side) of selected monolayer and trilayer membranes): Here are typical values ​​for the sphericity coefficients or ratios in the machine direction (MD) (length), transverse direction (TD) (width), and thickness direction (ND) (vertical height): MD / TD aspect ratio in the range of 0.75 to 1.50 MD / ND dimension ratio is in the range of 0.50 to 7.50 TD / ND dimension ratio is in the range of 0.50 to 5.00

[0072] According to at least selected embodiments of the present invention, the microporous membrane is produced by a dry stretching process, resulting in substantially round pores and a ratio of machine direction tensile strength to transverse direction tensile strength of 0.5 to 6.0, preferably 0.5 to 5.0. The method for producing the microporous membrane includes extruding a polymer into a nonporous precursor and biaxially stretching the nonporous precursor, the biaxial stretching comprising machine direction stretching and transverse direction stretching, the transverse direction stretching comprising simultaneous controlled machine direction relaxation.

[0073] According to at least selected embodiments, the present invention or application may address the above-mentioned needs and / or relate to new or improved battery separators, base films or membranes, batteries, cells, devices, systems, and / or vehicles, and / or methods of making and / or using such separators, films or membranes, batteries, cells, devices, systems, and / or vehicles, etc. According to at least certain embodiments, the present invention or application relates to biaxially oriented porous membranes, composites comprising biaxially oriented porous membranes, biaxially oriented microporous membranes, biaxially oriented macroporous membranes, battery separators, flat sheet membranes, and / or liquid retention media having improved charge capacity, and / or related methods, and / or methods of making, using, etc. According to at least certain selected embodiments, the possibly preferred dry-process separators of the present invention may be biaxially oriented and may have a preferred thickness range of 10 μm to 25 μm, having high strength, high porosity, and unexpectedly and / or surprisingly high charge capacity, e.g., high charge capacity at a 10 C rate. Furthermore, the high charge capacity and high porosity of the separators or membranes of the present invention can provide excellent charge rate and / or charge capacity performance in rechargeable and / or secondary lithium batteries, such as lithium ion batteries, and / or for high power and high energy applications, such as electric drive vehicles or hybrid electric vehicles, by way of example. According to at least certain embodiments, the present invention relates to improved microporous battery separators for secondary lithium batteries, improved microporous battery separators having enhanced or high charge rate and / or enhanced or high charge capacity in or for secondary lithium batteries, and / or related methods of manufacture, use, etc.

[0074] According to at least certain selected embodiments, the present invention provides an improved microporous battery separator for primary or secondary lithium batteries, fast charge / discharge batteries, fast charge / discharge batteries for drones, race cars, fast charging buses, electric vehicles, hybrid electric vehicles, and / or other vehicles, devices requiring high charge and / or discharge rate batteries, high charge and / or discharge rate primary or secondary lithium batteries, high charge and / or discharge rate primary lithium batteries, The present invention relates to lithium batteries, and / or high charge and / or discharge rate secondary lithium batteries, and / or related methods, and / or combinations thereof.

[0075] New or improved separators, battery separators, lithium battery separators, batteries, cells, and / or methods of making and / or using such separators, battery separators, lithium battery separators, cells and / or batteries; new or improved battery separators for lithium ion primary or secondary batteries; new or improved batteries or cells; new or improved vehicles or devices; methods, systems and battery separators for improving charge rates, discharge rates, cycle life, etc.; and / or combinations thereof as shown or described herein.

[0076] Preferably, new or improved battery separators, base films or membranes, batteries, cells, devices, systems, vehicles, and / or methods of making and / or using such separators, films or membranes, batteries, cells, devices, systems, vehicles, methods of increasing the charge rate, charge capacity, and / or discharge rate of batteries or cells, methods of improving batteries, systems including such batteries, vehicles including such batteries and / or systems, and / or the like; biaxially stretched porous membranes, composites including biaxially stretched porous membranes, biaxially stretched microporous membranes, biaxially stretched macroporous membranes, battery separators with improved charge capacity and related methods, and Methods of manufacture, methods of use, etc.; flat sheet membranes, liquid retention media; dry-process separators; biaxially oriented separators; preferably dry-process biaxially oriented separators having a thickness in the range of about 5 μm to 50 μm, improved strength, high porosity, and unexpectedly and / or surprisingly high charge capacity, e.g., 10 C rate charge capacity, etc.; separators or membranes, cells, equipment, systems, and / or vehicles, and / or the like, having high charge capacity and high porosity, excellent charge rate and / or charge capacity performance for high power and / or high energy applications in rechargeable and / or secondary lithium batteries, such as lithium ion batteries, are provided.

[0077] The present invention or application discloses or provides single or multiple or multi-layer separators, monolayer separators, trilayer separators, composite separators, laminated separators, co-extruded separators, coated separators, 1C or higher separators, at least 1C separators, batteries, cells, systems, equipment, vehicles, and / or the like; improved microporous battery separators for secondary lithium batteries, enhanced or high charge capacity for or in secondary lithium batteries, enhanced or high charge (C) rates, discharge (C) rates and / or related methods and / or combinations thereof of manufacture, use and / or the like.

[0078] The present invention may be embodied in other forms without departing from the spirit and essential attributes thereof. For example, in one embodiment, a lead-acid battery separator can be produced by using PE instead of PP and having a thickness of about 50 μm to 500 μm. Accordingly, reference should be made to the appended claims, rather than the foregoing specification, as indicating the scope of the invention.

[0079] The foregoing structure and method descriptions are presented for purposes of illustration only. The examples are used to disclose exemplary embodiments, including the best mode, and to enable any person skilled in the art to practice the invention, including making and using any device or system and performing the incorporated methods. These examples are not intended to be exhaustive or to limit the invention to the precise steps and / or form disclosed, many modifications and variations are possible in light of the above teachings. The features described herein may be combined in any combination. The steps of the methods described herein may be performed in any order that is physically possible. The patentable scope of the invention is defined in the appended claims. The scope of the claims is defined by the claims themselves, and includes other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they contain equivalent structural elements that do not differ substantially from the literal language of the claims.

[0080] The compositions and methods of the appended claims are not limited in scope by the specific compositions and methods described herein, but are intended as examples of several aspects of the claims. All functionally equivalent compositions and methods are intended to fall within the scope of the claims. Various modifications of the compositions and methods in addition to those shown and described herein are intended to fall within the scope of the appended claims. Furthermore, although only certain representative composition and method steps disclosed herein have been specifically recited, other combinations of composition and method steps are also within the scope of the appended claims, even if not specifically recited. Thus, although combinations of steps, elements, components, or components may be explicitly recited herein or hereinafter, other combinations of steps, elements, components, and components are included, even if not explicitly recited.

[0081] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein from "about" one particular value and / or from "about" another particular value. When such ranges are expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, it will be understood that the particular value forms a separate embodiment by the use of "about." It will be further understood that the endpoints of each range are significant in relation to the other endpoint, and independently of the other endpoint. "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances when the event or circumstance occurs and instances when it does not.

[0082] Throughout the description and claims of this specification, the term "comprise" and variations of words such as "comprising" and "comprises" mean "including, but not limited to," and are not intended to exclude, for example, other additives, components, integers, or steps. The terms "consisting essentially of" and "consisting of" can be used in place of "comprising" and "including" to provide more specific embodiments of the present invention and are also disclosed. "Exemplary" means "one example of" and is not intended to convey an indication of a preferred or ideal embodiment. "Such as" is used for descriptive or illustrative purposes, not in a limiting sense.

[0083] Unless otherwise noted, all numbers expressing geometric shapes, dimensions, and the like used in the specification and claims should be construed in light of significant digits and ordinary rounding approaches, at least without attempting to limit the application of the doctrine of equivalents to the application of the claims. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed invention belongs. Publications cited herein and the materials for which they are cited are specifically incorporated by reference. Moreover, the invention illustratively disclosed herein may suitably be practiced in the absence of any element not specifically disclosed herein.

Claims

1. MD / TD pore aspect ratio of 1.0, three-dimensional pore sphericity ratio (MD / TD / ND) ranging from 1.0 to 2.0, pores with an average pore diameter ranging from 0.09 to 0.99 μm, ratio of tensile strength in machine direction (MD) to tensile strength in transverse direction (TD) ranging from 1.4 to 1.6 (MD / TD), porosity ranging from 50% to 80%, thickness ranging from 15 to 20 μm, 500 kg / cm 2 ~700 kg / cm 2 Transverse direction (TD) tensile strength in the range of 700 kg / cm 2 ~950kg / cm 2 a Gurley (JIS) value in the range of 28 to 65 seconds; a transverse direction (TD) shrinkage when heated at 90°C for 1 hour of 0.1% or 0.2%, and when used in a rechargeable battery, the rechargeable battery exhibits a charge capacity of at least 108.64 mAh / g.

2. 10. The method of making a monolayer battery separator membrane of claim 1, wherein the microporous polypropylene dry-stretched film is produced by a stretching method comprising at least one of biaxial stretching, including machine direction stretching and transverse direction stretching with simultaneous controlled machine direction relaxation, simultaneous or sequential machine direction stretching and transverse direction stretching, and machine direction stretching followed by transverse direction stretching with simultaneous machine direction relaxation.

3. 10. The monolayer battery separator membrane of claim 1, wherein said microporous polypropylene dry stretch film has a porosity in the range of 60-80%.

4. 10. The monolayer battery separator membrane of claim 1, wherein said microporous polypropylene dry stretch film provides a battery with a C-rate of at least 5C.

5. 10. The monolayer battery separator membrane of claim 1, wherein said microporous polypropylene dry stretch film provides a battery with a C-rate of at least 10C.

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