Shutdown separators for battery systems

Abstract

A battery separator is provided comprising a low temperature shutdown layer, and the battery separator has a shutdown temperature of less than about 130°C, less than about 120°C, less than about 110°C, less than about 100°C, less than about 90°C, or less than about 80°C. The low temperature shutdown layer can contain a first and second polymeric component. For example, it may contain an ultrahigh molecular weight polyethylene and a low molecular weight polyolefin and / or wax.

Description

SHUTDOWN SEPARATORS FOR BATTERY SYSTEMSFIELD

[0001] The technology described herein generally relates to separators, membranes, and / or thin films, and more particularly to systems thereof incorporating low and / or various temperature shutdown features for battery systems, new or improved shutdown separators for secondary lithium or lithium ion batteries, safety separators, heat absorbing separators, coated separators, filled separators, blended separators, extruded separators, and batteries and / or secondary batteries ncorporating such separators, membranes, and / or thin films.BACKGROUND

[0002] Battery separators are microporous membranes that, among other roles, form physical barriers positioned between a cathode and an anode of a battery or cell to prevent the electrodes from physically contacting and causing, for instance, a short circuit. In lithium-ion batteries, for example, during operation, electrodes of the battery cell swell and contract based in part on heat generation, which can in turn affect a battery cell’s performance due to an applied internal pressure, or cause an explosion or fire. Further, as a battery’s energy density increases, battery cell performance and safety become more of an issue due to higher heat generation and thermal propagation in the event of a short.

[0003] In lithium ion rechargeable or secondary batteries separators may also be employed as shutdown separators as a part of a battery’s safety system. These safety systems may be employed to prevent or reduce thermal runaway caused by short circuiting or from physical damage, internal defects, overcharging, dendrites, or general overheating.

[0004] Consequently, there is a need for improved separators, membranes, and / or thin films that can be incorporated into batteries, battery cell systems, lithium ion batteries, or secondary lithium ion batteries to impart higher performance characteristics, and improved safety features over conventional battery separators or separator membranes, for instance separators that exhibit preferable shutdown features such as achieving shutdown at various selected or low temperatures.SUMMARY

[0005] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key featuresor essential features of the claimed subject matter, nor is it intended to be used in isolation as an aid in determining the scope of the claimed subject matter.

[0006] Embodiments of the technology described herein are directed towards reducing and / or stopping thermal propagation in a battery cell, for example through battery separator shutdown features, for example cutting off ionic current flow by blocking pores or removing electrolyte from separator pores at temperatures at or below about 130°C, at or below about 120°C, at or below about 110°C, at or below about 100°C, at or below about 90°C, or at or below about 80°C. Additionally, the technology described herein may generally provide heat absorption, improve wettability, and reduce and / or eliminate large scale heat generation of a battery cell.

[0007] According to some embodiments, a batter separator is provided comprising, consisting of, or consisting essentially of a low temperature shutdown layer, wherein the low temperature shutdown layer is configured to enable the separator to have a shutdown temperature of less than about 130°C, less than about 120°C, less than about 110°C, less than about 100°C, less than about 90°C, or less than about 80°C. The low temperature shutdown layer can comprise at least an ultrahigh molecular weight polyethylene and a low molecular weight polyolefin and / or wax. In some other instances, the low temperature shutdown layer is configured to increase the energy density of a battery cell.

[0008] According to some embodiments, the battery separator may comprise, consist of, or consist essentially of a porous, microporous, or nanoporous membrane comprising the low temperature shutdown layer on at least one side thereof. In some embodiments, the low temperature shutdown layer is provided on two sides of a porous or microporous membrane.

[0009] The porous or microporous membrane may comprise one or more polymers, polyolefin (PO), polypropylene (PP), polyethylene (PE), polyethylene terepthalate (PET), polytetrafluoroethylene (PTFE), PMI, PMA, non-woven fibers, or combinations thereof. The porous or microporous membrane may be a single layer membrane, a bilayer membrane, a trilayer membrane, or a multilayer membrane (and each layer may be the same or different).

[0010] In some embodiments, the low temperature shutdown layer is an inner layer or an outer layer of a multilayer porous membrane having two, three, four, five, six, seven, eight, nine, ten, or more layers. In some embodiments, the low temperature shutdown layer is extruded with or laminated to at least one other layer.

[0011] In some embodiments, the low temperature shutdown layer may comprise, consist of, or consist essentially of a first polymeric component and a second polymeric component. The firstpolymeric component may be one or more selected from an ultra-high molecular weight polyethylene (UHMWPE), a polypropylene, a polyethylene terepthalate (PET), a polyvinylidene difluoride (PVDF), a polyimide, a polyamide, a polytetrafluoroethylene (PTFE), copolymers, and combinations thereof. The second polymeric component may be at least one of a low molecular weight PE, a low molecular weight PP, a PE wax, or an oligomer of a polyolefinic polymer.

[0012] In some embodiments, the second polymeric component may be cross-linked. The second polymeric component may be present in an amount from about 1 wt.% to 50 wt.%

[0013] In some embodiments the low temperature shutdown layer may comprise additional components. For example, the layer may comprise inorganic particles. The inorganic particles may be ionically conductive or may not be ionically conductive. The inorganic particles may be one or more selected from LiNb(x)O(y), A12O3, Li3PO4, crystal, and glass. Further additional components may be non-woven fibers. The non-woven fibers may comprise PET, PP, PE, Polyimides, Polyamides, or combinations thereof.

[0014] According to some further embodiments, a battery cell is provided comprising an anode, a cathode, and a separator disposed between the anode and the cathode. In some instances, the separator comprises, consists of, or consists essentially of a low temperature shutdown layer, wherein the low temperature shutdown layer is configured to enable the separator to have a shutdown temperature of less than about 130°C, less than about 120°C, less than about 110°C., less than about 100°C., less than about 90°C., less than about 80°C.. The low temperature shutdown layer can comprise at least a first polymeric component and a second polymeric component For example, an ultrahigh molecular weight polyethylene and at least one of a low molecular weight PE, a low molecular weight PP, a PE wax, or an oligomer of a polyolefinic polymer.

[0015] Additional objects, advantages, and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or can be learned by practice of the invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Aspects of the technology presented herein are described in detail below with reference to the accompanying drawing figures, wherein:

[0017] FIG. 1 shows example configurations of a battery separator structure for a low temperature shutdown separator, in accordance with some aspects of the inventive technology described herein;

[0018] FIG. 2 is a schematic illustrating energy densities among battery systems comparative to a battery cell incorporating a shutdown separator, in accordance with some aspects of the technology described herein.

[0019] FIG. 3 is a slide showing Li or lithium related anode materials.

[0020] FIG. 4 is a schematic illustrating Volumetric energy density (Wh / 1) and gravimetric energy density (Wh / kg) for major rechargeable battery systems.

[0021] FIG.5 is a chart illustrating Hot ER measurement as a function of temperature showing shut down speed.

[0022] FIG. 6 is a slide illustrating Functions of Low Temperature Shut Down or Shutdown (LTSD) Separators.

[0023] FIG. 7 is a schematic illustrating proposed LTSD separators consisting of various layers.

[0024] FIG. 8 is a slide listing potential components of the LTSD separator and the base porous membrane components.

[0025] FIG. 9 is a schematic illustrating make up of a shutdown functional coating.

[0026] FIG. 10 is a graph of resistance versus temperature illustrating shutdown behavior.

[0027] FIG.11 is a DSC graph showing a first heating cycle, a second heating cycle and cooling cycle behaviors.DETAILED DESCRIPTION

[0028] The subject matter of aspects of the present disclosure is described with specificity herein to meet statutory requirements. However, the description itself is not intended to limit the scope of this patent. Rather, the inventors have contemplated that the claimed subject matter might also be embodied in other ways, to include different steps or combinations of steps similar to the ones described in this document, in conjunction with other present or future technologies. Moreover, although the terms “step” and / or “block” can be used herein to connote different elements of methods employed, the terms should not be interpreted as implying any particular order among or between various steps disclosed herein unless and except when the order of individual steps is explicitly described.

[0029] Accordingly, embodiments described herein can be understood more readily by reference to the following detailed description, examples, and figures. Elements, apparatus, and methods described herein, however, are not limited to the specific embodiments presented in the detailed description, examples, and figures. It should be recognized that the exemplary embodiments herein are merelyillustrative of the principles of the invention. Numerous modifications and adaptations will be readily apparent to those of skill in the art without departing from the spirit and scope of the invention

[0030] In addition, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range of “1.0 to 10.0” should be considered to include any and all subranges beginning with a minimum value of 1.0 or more and ending with a maximum value of 10.0 or less, e.g., 1.0 to 5.3, or 4.7 to 10.0, or 3.6 to 7.9.

[0031] All ranges disclosed herein are also to be considered to include the end points of the range, unless expressly stated otherwise. For example, a range of “between 5 and 10” or “5 to 10” or “5-10” should generally be considered to include the end points 5 and 10.

[0032] Further, when the phrase “up to” is used in connection with an amount or quantity; it is to be understood that the amount is at least a detectable amount or quantity. For example, a material present in an amount “up to” a specified amount can be present from a detectable amount and up to and including the specified amount.

[0033] Additionally, in any disclosed embodiment, the terms “substantially,” “approximately,” and “about” may be substituted with “within [a percentage] of’ what is specified, where the percentage includes 0.1, 1, 5, and 10 percent.

[0034] Separators or microporous membranes (also referred to herein as a film and / or thin film, separator, battery separator, shutdown separator, various temperature shutdown separator, or low temperature shutdown separator) are incorporated into batteries or cells to perform a variety of functions, for example to prevent electronic contact between positive and negative electrodes of a battery and enabling ionic transport between electrodes, acting as a thermal fuse as a shutdown feature, amongst others.

[0035] Specific energy and / or energy density of batteries or cells relate to characteristics of a battery or cell (for example chemistry, packaging, and / or size) that, in part, determine battery energy and electric range. With improvements in battery components and chemistry, higher energy batteries or cells (for example Li, Li-ion, Na-ion) can be made which enable higher energy output and electric range. Accordingly, high energy batteries, cells, and battery systems, can have higher operating temperatures, and additionally, in the event of a short, thermal propagation through the battery cell or system at or above the operating temperature can cause operational and safety issues, such as overheating, explosion, or fire.

[0036] It will be appreciated that conventional Li-based batteries or cells can be limited in their design and capabilities due to a lack of incorporated components / materials, systems, and / or methodologies which can be configured to handle the functionality, capabilities, and / or safety problems associated with higher energy density batteries or cells.

[0037] According to embodiments of the present technology, separators (also used herein interchangeably with porous / microporous membranes, and films / thin films) can be implemented in a battery, cell, battery system, or battery cell system, and configured to mitigate, reduce, and / or otherwise stop thermal propagation within the battery or battery system, that is separators provided herein provide shutdown capabilities to a battery system at various and / or low temperatures. In some other embodiments, separators, or low temperature shutdown separators, described herein can enable higher energy density in a rechargeable battery or battery system, for example being configured to enable an energy density of greater than 200 Wh / kg and / or greater than 250 wh / 1.

[0038] According to some embodiments, separators or membranes for battery systems, such as rechargeable batteries, are provided herein that incorporate shutdown features, that is microporous membranes having the ability to shutdown the ion or current flow between a battery’s anode and cathode in response to an overheating event, such as a short circuit.

[0039] As will be appreciated a battery generally comprises an anode, a cathode, a separator sandwiched between the anode and the cathode, and an electrolyte in ionic contact with the anode and the cathode via the separator. Separators described herein will generally be understood with reference to Li-ion rechargeable batteries, but the technology described herein is not so limited.

[0040] According to some embodiments a separator (or various temperature shutdown separator or low temperature shutdown separator can be implemented in a rechargeable battery with a Li related anode (i.e. LiR). A Li related anode (LiR) can be lithium metal or modified lithium metal, various lithium alloys (e.g. Si, Sn, etc.), and / or various carbons. As will be appreciated, an Li related anode can be composed of various combinations of the materials described here.

[0041] According to various embodiments, a low temperature shutdown (LTSD) separator can provide a plurality of functions to a battery system, more specifically to a rechargeable battery system incorporating a Li related anode. For instance, an LTSD separator can cut off local ionic current flow of a battery by blocking pores and / or by removing or stopping electrolyte from and / or through the pores in the separator. Further, an LTSD separator can absorb heat generated by an internal short in a battery cell and further reduce and / or avoid propagation of heat from internal shorting areas to other areas in abattery cell. Additionally, large scale heat generation of a battery cell can be reduced or eliminated through implementation of an LTSD separator by cutting off the electrochemical reactions of the cell. In some instances, an LTSD separator according to the present technology can improve the wettability of the separator and furthermore help a battery system pass critical battery safety tests.

[0042] In some embodiments, a separator (or various temperature shutdown separator or LTSD separator), comprises, consist of, or consist essentially of one or more shutdown layers. In some embodiments, the one or more shutdown layers may be provided on one or two surfaces of a porous or microporous membrane (e.g. a polymer membrane). In some embodiments, the shutdown layer may be an inner or outer layer of a multilayer porous or microporous membrane having two, three, four, five, six, seven, eight, nine, or ten layers. In some embodiments, the shutdown layer may be extruded with or laminated to at least one other layer.

[0043] For example, a shutdown layer comprising a heat absorption material, referred to in some embodiments as a LTSD layer may be used as the shutdown layer in some embodiments. According to various embodiments, an LTSD layer comprises at least a first polymeric component and a second polymeric component. The first polymeric component may be or more selected from an ultra-high molecular weight polyethylene (UHMWPE), a polypropylene (PP), a polyethylene terepthalate (PET), a polyvinylidene difluoride (PVDF), a polyimide, a polyamide, a polytetrafluoroethylene (PTFE), copolymers, blends, and combinations thereof. The second polymeric component may be at least one of a low molecular weight PE, a low molecular weight PP, a PE wax, or an oligomer of a polyolefinic polymer, and combinations thereof.

[0044] In some preferred embodiments, a high-density ultra-high molecular weight polyethylene (UHMWPE) and a lubricant and / or wax, for example one or more of a low molecular weight polyethylene (PE) or PE wax or oligomer or combination thereof may be used to form the low temperature shutdown layer. In some embodiments, the low MW PE or wax in a given composition can be crosslinked. For example, a LTSD layer can incorporate a composition comprising an UHMWPE and a LMWPE, where the LMWPE is crosslinked. With reference to the UHMWPE material, in some instances the UHMWPE can be extruded using a lubricant.

[0045] In some embodiments, a parameter of any of the components or layers of a separator can be varied, for example the amount of a component, the MW of a component, the structure of a component or layer, and / or the temperature distribution applied to a component and / or layer.

[0046] According to various embodiments, the materials for the LTSD layer can be selected to achieve various shutdown temperatures. The type and / or amount of PE wax and / or crosslinking may be selected to achieve a shutdown temperature of 80°C or less, 90°C or less, 100°C or less, 110°C or less, 120°C or less, or 130°C or less.

[0047] In some embodiments a LTSD separator can comprise a base porous, microporous or nanoporous membrane (base film) and an LTSD layer provided on at least one surface thereof. The LTSD layer can comprise a UHMWPE and another material, such as PE wax, low MW PE, or low MW polypropylene (PP). The another material can be crosslinked in the LTSD layer composition. For example, a low MW PE may be crosslinked to a certain degree in the UHMWPE and low MW PE composition. In some embodiments, the LTSD layer can be extruded, for instance using a lubricant. As will be appreciated, utilizing materials and compositions described herein uniform and thinner separators or separator layers can be achieved that enable higher strength and various temperature shutdown separators. Additionally, using extrusion aids can support achieving suitable mechanical strengths of a separator when incorporating UHMWPE. Further, according to some embodiments, adhesive properties can be provided to such separators and / or separator layers.

[0048] According to some embodiments, a separator can comprise a porous or microporous membrane (e.g. a base porous or microporous membrane or film) and an LTSD layer. The base microporous membrane can comprise PE, PP, combinations thereof, PET, PTFE, PMI, PMA, or comprise non-woven fibers. In some instances, the base microporous membrane can be configured as a microporous membrane described herein.

[0049] In some embodiments, an LTSD layer comprises a polymer. The polymer can comprise a wax, PP, PE, PP / PE blends, PVDF, PVDF(HFP), PEO, PMMA, combinations thereof, amongst others. A polymer of an LTSD layer can further comprise one or more inorganic particles, such as LiNb(x)O(y), AI2O3, LiaPCU, or an ionically conductive or non-conductive ceramic, crystal, glass, or combination thereof. A polymer of an LTSD layer can further comprise high temperature stable polymer particles, for example PTFE, polyamides, polyimides, PET, PVDF, PP, PE, combinations thereof, amongst others. A polymer of an LTSD layer can further comprise non-woven fibers, for example fibers of PET, PE, PP, polyimides, polyamides, and / or combinations thereof, amongst others.

[0050] As will be appreciated, a separator (or LTSD separator) or a LTSD layer can be coated, extruded, laminated, and / or sandwiched with various other or additional layers.

[0051] A microporous membrane as described herein (or base microporous membrane or layer) can comprise one or more layers of a polyolefin, a fluorocarbon, a polyamide, a polyester, a polyacetal (or a polyoxymethylene), a polysulfide, a polyvinyl alcohol, a polyvinylidene, co-polymers thereof, or combinations thereof. In some embodiments, a microporous membrane described herein comprises one or more layers of a polyolefin (PO) such as a polypropylene (PP) or a polyethylene (PE), a blend of polyolefins, one or more co-polymers of a polyolefin, blends, or a combination of any of the foregoing. It will be appreciated that a polyolefin as used in accordance with the present technology can be of any molecular weight not inconsistent with the characteristics of the microporous membranes or separators described herein. Additionally, a microporous membrane can comprise PET, PTFE, PMI, PMA, nonwoven fibers, or a combination of any of the foregoing.

[0052] A microporous membrane can in some instances comprise a semi-crystalline polymer, such as polymers having a crystallinity in the range of 20 to 80%. The microporous membrane can in some aspects or embodiments comprise a dry process membrane, a wet process membrane, a machine direction (MD) or transverse direction (TD) stretched membrane, a biaxially (MD and TD) stretched membrane, a BNBOPP membrane, a particle stretch membrane, or combinations thereof. A dry process or dry stretch process membrane may be preferred in certain embodiments. In some embodiments, a microporous membrane or separator described herein can have a structure of a single layer, a bi-layer, a tri-layer, or multilayers. For example, a tri-layer or multilayer membrane can comprise two outer layers and one or more inner layers. In some instances, a microporous membrane can comprise 1, 2, 3, 4, 5, or more inner layers. In some other instances, each of the layers can be coextruded and / or laminated together. In some embodiments, a microporous membrane or separator as described herein can have any single layer, bi-layer, tri-layer, or multi-layer construction of PP and / or PE.

[0053] A microporous membrane described herein can additionally comprise fillers, elastomers, wetting agents, lubricants, flame retardants, nucleating agents, and other additional elements and / or additives not inconsistent with the objectives of this disclosure.

[0054] In some embodiments, the LTSD layer can comprise a polymer and / or polyolefin and a binder material and / or other additive. According to some aspects, the LTSD layer or material is present in the overall separator system in an amount of at least 2% by weight or volume. In some example embodiments, the LTSD layer or material can be present in an amount from 2%-5%, from 2%-10%, from 2%-20%, from 2%-30%, from 2%-40%, from 2%-50% by weight (wt). In some otherembodiments, the LTSD layer or material is present in amount up to 50%, up to 60%, up to 70%, up to 80%, up to 90%, up to 100% by weight.

[0055] The LTSD layer can be positioned one or more surfaces of a polymer membrane (e.g. base microporous membrane), that is the LTSD layer can be positioned on a first planar surface of the polymer membrane and / or on a second planar surface of the polymer membrane. In some instances, the heat absorption layer can be positioned between layers of the polymer membrane. In some instances, the separator or separator system does not comprise a base microporous film, that is the separator is made up of only LTSD material and additives.

[0056] Accordingly, a separator can comprise a polymer membrane (i.e. one or more layers of a polyolefin), one or more LTSD layers, and optionally one or more additives or modifiers. In some instances, a LTSD layer can be positioned on one surface (e.g. a first surface) of the polymer membrane and / or on the other surface (e.g. a second surface) of the polymer membrane. In some further instances, a LTSD layer can be positioned between two polymer membrane layers.

[0057] It is contemplated that the LTSD layer can be coated, extruded, laminated, sandwiched on, or otherwise affixed to one or more substrate materials, for example a polymer membrane. Additionally, it is contemplated that any known binders and / or glues can be utilized in or in conjunction with any of the layers.

[0058] In some embodiments, a LTSD separator as described herein can be incorporated into a battery or cell. A battery cell can include, amongst other components, an anode, a cathode, and a separator disposed between the anode and cathode. The separator disposed between the anode and cathode can be a heat absorption separator as described herein.

[0059] In some instances, for example during operation or in the event of a short, the LTSD separator can provide shutdown to a battery system at or below a temperature of about 80°C, about 90°C, about 100°C, about 110°C, about 120°C, or about 130°C.

[0060] According to some aspects, the low temperature shutdown (or various temperature shutdown) separator can enable a battery or cell having improved volumetric energy density (Wh / 1) and / or gravimetric energy density (Wh / kg). In some instances, for example, the separator can enable a battery or cell having a volumetric energy density of greater than 300 Wh / 1, greater than 400 Wh / 1, greater than 500 Wh / 1, or greater than 600 Wh / 1. In some instances, for example, the heat absorption separator can enable a battery or cell having a gravimetric energy density of greater than 300 Wh / kg, greater than 400 Wh / kg, or greater than 500 Wh / kg.

[0061] Referring now to the figures or FIGs, FIG. 1 (or figure 1) depicts example configurations of a battery separator structure 102, 104, 106, 108 (e.g. a LTSD separator) with which some embodiments of the present disclosure can be employed for reducing thermal propagation and / or absorbing heat in a battery cell and / or providing shutdown features for the reduction or elimination of large scale heat generation in a battery cell in accordance with some aspects of the technology described herein. It should be understood that this and other arrangements described herein are set forth as only examples. Other arrangements and elements can be used in addition to, or instead of, those shown, and some elements may be omitted altogether for the sake of clarity.

[0062] Among components shown, battery separator 102 includes microporous membrane 102a and low temperature shutdown layer 102b affixed to one surface of microporous membranel02a. Battery separator 104 includes microporous membranes 104a and 104a' and low temperature shutdown layer 104b. Battery separator 106 includes microporous membrane 106a, and low temperature shutdown layers 106b and 106b'. In some embodiments, battery separator 108 comprises a low temperature shutdown layer and / or layers 108a, which in some instances comprises at least two components, such as a UHMWPE and at least one of a low molecular weight PE, a low molecular weight PP, a PE wax, or an oligomer of a polyolefinic polymer.

[0063] Turning now to FIG. 2, a schematic illustrating the reduction of thermal propagation and / or the absorption of heat in a battery cell provided by an implemented heat absorption battery separator according to some embodiments described herein is shown. Battery cell 202 is provided having an internal short 204 which causes heat generation and propagation within the battery cell 202. A battery separator (e.g. a heat absorption separator) is implemented in the battery cell having a microporous membrane 208 and a heat absorption layer 210. With the implementation of the battery separator in accordance with embodiments described herein, battery cell 202' is provided having an internal short 204' where any heat propagation or transfer of heat energy is reduced and / or stopped.

[0064] According to some further embodiments, a method of reducing and / or stopping thermal propagation or high heat generation in a battery cell is provided, for example thermal propagation due to normal operating temperatures of a high energy density battery or due to an internal short within a battery cell. According to some example embodiments, methods include providing separator comprising a microporous membrane, for example a microporous membrane comprising one or more layers of a polyolefin. A microporous membrane can have on one or more planar sides coated or layered with a layer comprising a blend of a polyolefin polymer and an oligomer of a polyolefinic polymer. In oneexample embodiment, a low temperature shutdown layer is a composition comprising an ultra-high molecular weight polyethylene and at least one of a low molecular weight PE, a low molecular weight PP, or a PE wax. In some further embodiments the low molecular weight PE, a low molecular weight PP, or a PE wax is crosslinked.

[0065] The low temperature shutdown material or composition can be coated otherwise affixed (e g. extruded, laminated) to the microporous membrane. According to some embodiments, the microporous membrane is coated or layered with a layer compromising at least 2% by weight or volume of a low temperature shutdown composition. The separator comprising a low temperature shutdown material or composition can be implemented in a battery cell and subjected to a heat range consistent with a high energy density battery, for instance a battery having a Li-related anode.

[0066] In accordance with at least selected aspects, objects or embodiments, there are provided or described herein technology, separators, membranes, and / or thin films, systems thereof incorporating low and / or various temperature shutdown features for battery systems, new or improved shutdown separators for secondary lithium or lithium ion batteries, safety separators, heat absorbing separators, coated separators, filled separators, blended separators, extruded separators, and batteries and / or secondary batteries incorporating such coated or filled separators, membranes, and / or thin films.

[0067] A possibly preferred embodiment is shown as separator, construction or product 102 in Fig. or Figure 1, a second possibly preferred embodiment is shown as separator, construction or product 106 in Figure 1, a third possibly preferred embodiment is shown as separator, construction or product 108 in Figure 1, and a fourth possibly preferred embodiment is shown as separator, construction or product 104 in Figure 1.

[0068] Separators, constructions or products 102 and 106 of Figure 1 may preferably be coated in at least certain embodiments. Separators, constructions or products 102, 106, and 108 of Figure 1 may preferably be extruded or co-extruded in at least certain embodiments. Separators, constructions or products 102 and 106 of Figure 1 may preferably be coated on at least one side with a low temperature shutdown (LTSD) coating of low MW PE dispersed in an aqueous or organic solvent in at least certain embodiments, preferably the anode side of the separator. Separators, constructions or products 106 of Figure 1 may preferably be coated on at least one side with a ceramic coating, preferably the cathode side of the separator. Separators, constructions or products 108 of Figure 1 may preferably be a fdled or blended polymer membrane such a polyolefin membrane or blend including a low MW PE, a low melting point polymer, a wax, an oligomer, a highly crystalized polymer, or combinations thereof in atleast certain embodiments, preferably between two polyolefin membranes. Separators, constructions or products 104 of Figure 1 may preferably have a coated or extruded low temperature shutdown (LTSD) center layer of low MW PE dispersed in an aqueous or organic solvent or of polyolefin polymer membrane or blend including a low MW PE, a low melting point polymer, a wax, an oligomer, a highly crystalized polymer, or combinations thereof in at least certain embodiments, preferably the center layer is extruded or co-extruded between two polyolefin membranes. Separators, constructions or products 102, 104, and 106 of Figure 1 may preferably include dry process polyolefin membranes.

[0069] Separators, constructions or products 102, 104, 106, and 108 of Figure 1 may preferably include LTSD coatings, layers or membranes that provide at least one of that also absorb and / or dissipate heat (suppress heat, suppress heat propagation, avoid thermal runaway, avoid fires, avoid hot spots, localize hot spots, provide micro-spot heat absorption, and combinations thereof), preferably include a low MW and / or high crystallinity material or polymer, may preferably include a ceramic layer with acrylate or PE particles, and may include boehmite, A12O3, TiO2, or SiO2 particles, may preferably include a PVDF or PVDF-HFP layer, may prevent oxidation, may increase dry adhesion and / or wet adhesion, and / or may preferably shut down below 130 deg C, below 120 deg C, below 110 deg C, below 100 deg C, below 90 deg C, or below 80 deg C, with below 110 deg C shutdown possibly most preferred.

[0070] In accordance with selected embodiments, aspects or objects, there is disclosed or provided a battery separator comprising a low temperature shutdown layer, and the battery separator has a shutdown temperature of less than about 130°C, less than about 120°C, less than about 110°C, less than about 100°C, less than about 90°C, or less than about 80°C. The low temperature shutdown layer can contain a first and second polymeric component. For example, it may contain an ultrahigh molecular weight polyethylene and a low molecular weight polyolefin and / or wax.

[0071] In accordance with certain embodiments, aspects or objects, there is disclosed or provided a battery separator comprising: a low temperature shutdown layer, wherein the low temperature shutdown layer comprises a polymeric material and the battery separator has a shutdown temperature of less than about 130°C, and wherein the shutdown layer does both of the following: 1) cuts off the local ionic current flow of the battery; and 2) absorbs heat generated in a battery.

[0072] In accordance with certain selected embodiments, aspects or objects, there is disclosed or provided a battery separator or membrane comprising: a microporous polymeric base film and a low temperature shutdown layer, wherein the low temperature shutdown layer comprises a polymeric material and the battery separator has a shutdown temperature of less than about 130°C, less than about 120°C, less than about 110°C, less than about 100°C, less than about 90°C, or less than about 80°Cand wherein the shutdown layer does one or both of the following: 1) cuts off the local ionic current flow of the battery; and 2) absorbs heat generated in a battery.

[0073] In accordance with at least selected embodiments, aspects or objects, there is disclosed or provided a battery separator or membrane comprising: a microporous substrate and a low temperature shutdown layer, wherein the low temperature shutdown layer comprises at least a first polymeric component and a second polymeric component, wherein the second polymeric component is present in an amount of from 1 to 50 wt.%, and the battery separator has a shutdown temperature of less than about 130°C, less than about 120°C, less than about 110°C, less than about 100°C, less than about 90°C, or less than about 80°C, and wherein the shutdown layer does both of the following: 1) cuts off the local ionic current flow of the battery; and 2) absorbs heat generated in a battery.

[0074] Many different arrangements of the various components and / or steps depicted and described, as well as those not shown, are possible without departing from the scope of the claims below.Embodiments of the present technology have been described with the intent to be illustrative rather than restrictive. Alternative embodiments will become apparent from reference to this disclosure. Alternative means of implementing the aforementioned can be completed without departing from the scope of the claims below. Certain features and subcombinations are of utility and can be employed without reference to other features and subcombinations and are contemplated within the scope of the claims.

Claims

CLAIMS1. A battery separator comprising: a low temperature shutdown layer, wherein the low temperature shutdown layer comprises a polymeric material and the battery separator has a shutdown temperature of less than about 130°C, and wherein the shutdown layer does both of the following: 1) cuts off the local ionic current flow of the battery; and 2) absorbs heat generated in a battery.

2. The battery separator of claim 1, having a shutdown of less than about 120°C.

3. The battery separator of claim 1, having a shutdown of less than about 100°C.

4. The battery separator of claim 1, having a shutdown of less than about 90°C.

5. The battery separator of claim 1, having a shutdown of less than about 80°C.

6. The battery separator of claim 1, wherein the low temperature shutdown layer comprises at least a first polymeric component and a second polymeric component.

7. The battery separator of claim 6, wherein the first polymeric component is one or more selected from an ultra-high molecular weight polyethylene (UHMWPE), a polypropylene, a polyethylene terpthalate (PET), a polyvinylidene difluoride (PVDF), a polyimide, a polyamide, a polytetrafluoroethylene (PTFE), and combinations thereof.

8. The battery separator of claim 6, wherein the second polymeric component is at least one of a low molecular weight PE, a low molecular weight PP, a PE wax, or an oligomer of a polyolefinic polymer.

9. The battery separator of claim 6, wherein the second polymeric component is cross-linked.

10. The battery separator of claim 8, wherein the second polymeric component is present in an amount of from 1 to 50 wt.%.

11. The battery separator of claim 1, wherein the battery separator consists of the low temperature shutdown layer.

12. The battery separator of claim 1, wherein the low temperature shutdown layer is provided on one surface of a porous membrane.

13. The battery separator of claim 12, wherein the low temperature shutdown layer is provided on two surfaces of the porous membrane.

14. The battery separator of claim 1, wherein the low temperature shutdown layer is an inner layer or an outer layer of a multilayer porous membrane.

15. The battery separator of claim 14, wherein the low temperature shutdown layer is an inner layer of the multilayer porous membrane.

16. The battery separator of claim 14, wherein the low temperature shutdown layer is an outer layer of the multilayer membrane.

17. The battery separator of claim 1, wherein the low temperature shutdown layer is extruded with or laminated to another layer.

18. The battery separator of claim 2, wherein the low temperature shutdown layer comprises inorganic particles.

19. The battery separator of claim 6, the low temperature shutdown layer further comprising inorganic particles.

20. The battery separator of claim 19, wherein the inorganic particles are ionically conductive.

21. The battery separator of claim 19, wherein the inorganic particles are not ionically conductive.

22. The battery separator of claim 19, wherein the inorganic particles are one or more selected fromLiNb(x)O(y), A12O3, Li3PO4, crystal, and glass.

23. The battery separator of claim 6, the low temperature shutdown layer further comprising nonwoven fibers.

24. The battery separator of claim 23, wherein the non-woven fibers comprise PET, PP, PE, Polyimides, Polyamides, or combinations thereof.

25. The battery separator of at least one of claims 12-16, wherein the membrane comprises PP, PE, PTFE, PMI, PMA, PTFE, non-woven fibers, or combinations thereof.

26. The battery separator of at least one of claims 12-16, wherein the porous membrane is a single layer membrane, a bilayer membrane, a trilayer membrane, or a multilayer membrane.

27. A battery cell comprising: an anode; a cathode; a separator according to claim 1 disposed between the anode and the cathode; and an electrolyte in ionic communication with the anode and the cathode via the separator.

28. The battery cell of claim 27, comprising a lithium-related anode.

29. The battery cell of claim 28, wherein the lithium-related anode consists essentially of lithium.

30. The battery cell of claim 28, wherein the lithium-related anode comprises a lithium alloy.

31. The battery cell of claim 28, wherein the lithium-related anode comprises carbon.

32. The battery cell of claim 27, wherein the battery separator comprises a first polymeric component and a second polymeric component.

33. The battery cell of claim 32, wherein the first polymeric component is a UHMWPE and the second polymeric component is at least one of a low MW PE, a low MW PP, or a polymeric wax.

34. A LTSD separator comprising the LTSD separator shown in Fig. 9.

35. The LTSD separator of Fig. 9 having a ceramic coating over a LTSD layer.

36. A battery separator or membrane comprising: a microporous polymeric base film and a low temperature shutdown layer, wherein the low temperature shutdown layer comprises a polymeric material and the battery separator has a shutdown temperature of less than about 130°C, less than about 120°C, less than about 110°C, less than about 100°C, less than about 90°C, or less than about 80°Cand wherein the shutdown layer does one or both of the following: 1) cuts off the local ionic current flow of the battery; and 2) absorbs heat generated in a battery.

37. A battery separator or membrane comprising: a microporous substrate and a low temperature shutdown layer, wherein the low temperature shutdown layer comprises at least a first polymeric component and a second polymeric component, wherein the second polymeric component is present in an amount of from 1 to 50 wt.%, and the battery separator has a shutdown temperature of less than about 130°C, less than about 120°C, less than about 110°C, less than about 100°C, less than about 90°C, or less than about 80°C, and wherein the shutdown layer does both of the following: 1) cuts off the local ionic current flow of the battery; and 2) absorbs heat generated in a battery.

38. New or improved separators, membranes, and / or thin films, systems thereof incorporating low and / or various temperature shutdown features for battery systems, new or improved shutdown separators for secondary lithium or lithium ion batteries, safety separators, heat absorbing separators, coated separators, filled separators, blended separators, extruded separators, and batteries, battery systems, and / or secondary batteries incorporating such separators, membranes, and / or thin films as shown or described herein.

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