PATENT DOCUMENT

Publication Number: US-10153474-B1
Application Number: US-201615266309-A
Country: US
Kind Code: B1

Title: Separators having improved temperature ranges for battery shutdown

Abstract:
Battery separators are presented having improved temperature ranges for battery shutdown. The battery separators include a first layer having a first shutdown temperature range, a second layer having a second shutdown temperature range, and a third layer having a third shutdown temperature range. The first shutdown temperature range and the second shutdown temperature range have a first overlap in temperature. The second shutdown temperature range and third shutdown temperature range have a second overlap in temperature. In some embodiments, the second layer is disposed between the first layer and the third layer to create a sandwiched structure.

Claims:
What is claimed is: 
     
       1. A battery separator, comprising:
 a first layer having a first shutdown temperature range wherein the first layer comprises at least one of polyethylene, polypropylene, and polyvinyl chloride; 
 a second layer having a second shutdown temperature range wherein the second layer comprises at least one of polymethyl methacrylate, polybutylene terephthalate, and poly ethylene terephthalate; and 
 a third layer having a third shutdown temperature range;
 wherein the first shutdown temperature range and second shutdown temperature range have a first overlap in temperature of at least 30° C.; and 
 wherein the second shutdown temperature range and third shutdown temperature range have a second overlap in temperature of at least 30° C. 
 
 
     
     
       2. The battery separator of  claim 1 , wherein the first shutdown temperature range and third shutdown temperature range do not overlap. 
     
     
       3. The battery separator of  claim 1 , further comprising a ceramic layer. 
     
     
       4. The battery separator of  claim 3 , wherein the ceramic layer has a melting temperature above 600° C. 
     
     
       5. A battery separator, comprising:
 a first layer having a first shutdown temperature range wherein the first layer comprises at least one of polyethylene, polypropylene, and polyvinyl chloride; 
 a second layer having a second shutdown temperature range wherein the second layer comprises at least one of polymethyl methacrylate, polybutylene terephthalate, and poly ethylene terephthalate; 
 a third layer having a third shutdown temperature range; and
 wherein the second layer is disposed between the first layer and third layer to create a sandwiched structure; 
 wherein the first shutdown temperature range and second shutdown temperature range have a first overlap in temperature of at least 30° C.; and 
 wherein the second shutdown temperature range and third shutdown temperature range have a second overlap in temperature of at least 30° C. 
 
 
     
     
       6. The battery separator of  claim 5 , wherein the first shutdown temperature range and third shutdown temperature range do not overlap. 
     
     
       7. The battery separator of  claim 5 , wherein the first shutdown temperature range spans 80-250° C. 
     
     
       8. The battery separator of  claim 5 , further comprising a ceramic layer. 
     
     
       9. The battery separator of  claim 8 , wherein the ceramic layer has a melting temperature above 600° C. 
     
     
       10. A battery separator, comprising:
 a first layer having a first shutdown temperature range of 80-250° C. wherein the first layer comprises at least one of polyethylene, polypropylene, and polyvinyl chloride; 
 a second layer having a second shutdown temperature range of 150-300° C. wherein the second layer comprises at least one of polymethyl methacrylate, polybutylene terephthalate, and poly ethylene terephthalate; and 
 a third layer having a third shutdown temperature range of 250-450° C. 
 
     
     
       11. A battery comprising:
 a cathode; 
 an anode; and 
 a separator according to  claim 1  disposed between the cathode and the anode. 
 
     
     
       12. A battery comprising:
 a cathode; 
 an anode; and 
 a separator according to  claim 5  disposed between the cathode and the anode. 
 
     
     
       13. A battery comprising:
 a cathode; 
 an anode; and 
 a separator according to  claim 10  disposed between the cathode and the anode.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application Ser. No. 62/235,109, filed Sep. 30, 2015, and entitled “SEPARATORS HAVING IMPROVED RANGES FOR BATTERY SHUTDOWN”, which is incorporated herein by reference in its entirety. 
    
    
     FIELD 
     This disclosure relates generally to batteries, and more particularly, to separators having improved temperature ranges for battery shutdown. 
     BACKGROUND 
     Separators represent structures in a battery, such as interposed layers, that prevent physical contact of cathodes and anodes while allowing ions to transport therebetween. Separators are formed of materials having pores that provide channels for ion transport, which may include absorbing an electrolyte that contains the ions. Materials for separators are often selected according to softening temperatures, above which, pores rapidly collapse and choke off ion transport. Such softening temperatures may allow separators to arrest operation of the battery when heat generated therein exceeds a safety threshold (e.g., a critical operating temperature). 
     A shutdown temperature range is typically associated with separators. The shutdown temperature range can be bound by a lower temperature limit and an upper temperature limit. Within the lower temperature limit and the upper temperature limit, the separator offers a high resistance to ion transport. The lower temperature limit corresponds to an onset of pore collapse, which rapidly chokes off ion transport through the separator. Chemical reactions in the battery therefore are arrested and the battery “shuts down”. The upper temperature limit corresponds to a breakdown of the separator, which may include melting and chemical decomposition. At the upper temperature limit, ion-transport begins to increase, which may stem from direct contact between a cathode and an anode. 
     The battery industry seeks to improve the temperature shutdown range associated with separators. Such improvement may involve decreasing the lower temperature limit, increasing the upper temperature limit, or both. 
     SUMMARY 
     The embodiments described herein relate to battery separators having improved temperature ranges for battery shutdown. In some embodiments, the battery separators include a first layer having a first shutdown temperature range, a second layer having a second shutdown temperature range, and a third layer having a third shutdown temperature range. The first shutdown temperature range and the second shutdown temperature range have a first overlap in temperature. Likewise, the second shutdown temperature range and third shutdown temperature range have a second overlap in temperature. 
     In some embodiments, the battery separators include a first layer having a first shutdown temperature range, a second layer having a second shutdown temperature range, and a third layer having a third shutdown temperature range. The second layer is disposed between the first layer and the third layer to create a sandwiched structure. The first shutdown temperature range and the second shutdown temperature range have a first overlap in temperature and the second shutdown temperature range and third shutdown temperature range have a second overlap in temperature. No overlap exists between the first shutdown temperature range and third shutdown temperature range. 
     In some embodiments, the battery separators include a first layer having a first shutdown temperature range with a first lower limit from 70-125° C. and a first upper limit from 230-270° C.; a second layer having a second shutdown temperature range with a second lower limit from 130-170° C. and a second upper limit from 280-320° C.; and a third layer having a third shutdown temperature range with a third lower limit from 230-270° C. and a third upper limit from 430-470° C. For example, and without limitation, the first shutdown temperature range can span 80-250° C., the second shutdown temperature range can span 150-300° C., and the third shutdown temperature range can span 250-450° C. 
     Other embodiments for the battery separators are described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIG. 1  is a schematic diagram is presented of a battery having a separator in accordance with embodiments of this disclosure. 
         FIG. 2A  is a schematic cross-section of a portion of a battery separator in accordance with embodiments of this disclosure. 
         FIG. 2B  is a schematic cross-section of a portion of a battery separator having a structure with a symmetric arrangement of layers about a center, in accordance with embodiments of this disclosure. 
         FIG. 2C  is a schematic cross-section of the battery separator shown in  FIG. 2B , but where ceramic layers are disposed onto exterior-facing surfaces of the structure, in accordance with embodiments of this disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     Now referring to  FIG. 1 , a schematic diagram is presented of a battery  100  having a separator  102  in accordance with embodiments of this disclosure. The separator  102  partitions the battery into a first portion  106  and a second portion  108 . The first portion  106  contains a cathode  110  and the second portion  108  contains an anode  112 . The separator  102  therefore physically and electrically isolates the cathode  110  from the anode  112 , thereby allowing the battery  100  to control a distribution of charge therein. In  FIG. 1 , the first portion  106  and the second portion  108  are depicted as having space on either side of the separator  102 . However, this depiction is for purposes of illustration only. The separator  102  may be in physical contact with the cathode  110 , the anode  112 , or both (i.e., no space). During such contact, the cathode  110  and the anode  112  are maintained on opposite sides of the separator  102 . 
     The separator  102  is formed of one or more porous materials that enable ion transport therethrough. The separator  102  includes a first layer having a first shutdown temperature range, a second layer having a second shutdown temperature range, and a third layer having a third shutdown temperature range. The first shutdown temperature range and the second shutdown temperature range have a first overlap in temperature and the second shutdown temperature range and third shutdown temperature range have a second overlap in temperature. In various embodiments, the first shutdown temperature range and third shutdown temperature range do not overlap. Aspects of the separator  102  will be described further in relation to  FIGS. 2A-2C . 
     The battery  100  includes an electrolyte  114  that contains ions  116  therein. The electrolyte  114  serves as a medium for ion transport. The ions  116  may be cations having a positive charge (e.g., lithium cations). In some embodiments, the electrolyte  114  is a fluid medium that may become absorbed within pores of the separator  102 . During operation of the battery  110 , the electrolyte  114  enables transport of the ions  116  from the cathode  110  to the anode  112  (i.e., charging) and from the anode  112  to the cathode  110  (i.e., discharging). Such transport occurs through pores in the separator  102 . Motion of the ions  116  during charging is illustrated in  FIG. 1  by single arrows  118 . Motion of the ions  116  during discharging is illustrated in  FIG. 1  by double arrows  120 . 
     During operation, the battery  100  may charge by coupling to an electrical power source  122  or may discharge by coupling to an electrical load  124 . The battery  100  may also be electrically isolated to preserve a charge state (e.g., over-charged, fully-charged, fully-discharged, etc.). Non-limiting examples of the electrical power source  122  include a DC power source and an AC power source. In  FIG. 1 , the electrical power source  122  is depicted as the DC power source, although this depiction is not intended as limiting. The electrical load  124  can be any type of component that consumes electrical power. For example, and without limitation, the electrical load  124  may be a motor, a pump, an actuator, a display, a computer, a heater, a lamp, etc. Other types of electrical loads  124  are possible. In  FIG. 1 , the electrical load  124  is depicted as a resistor, although this depiction is for purposes of illustration only. 
     The battery  100  may be incorporated within a circuit  126  to facilitate charging, discharging, or electrical isolation. The circuit  126  may include the electrical power source  122 , the electrical load  124 , or both. Multiple instances of the electrical power source  122  and the electrical load  124  are also possible. For purposes of clarity, however,  FIG. 1  illustrates the circuit  126  as having a single electrical power source  122  and a single electrical load  124 . A switch  128  may be employed in the circuit  124  to selectively establish a pathway for charging  130 , a pathway for discharging  132 , or an open circuit for electrical isolation. In  FIG. 1 , the switch  128  is shown establishing the open circuit (i.e., disconnected from the pathway for charging  130  and the pathway for discharging  132 ). 
     In operation, i.e., to charge the battery  100 , the switch  128  is displaced to provide electrical continuity for the pathway for charging  130 . In response, a charging flow of current  134  travels from the cathode  110  to the anode  112 . The charging flow of current  134  is driven by a voltage potential of the electrical power source  122 . In  FIG. 1 , the charging flow of current  134  is represented by a dashed line that has arrows indicating a direction of charging flow. Concomitantly, ions  116  in the electrolyte  114  flow from the cathode  110 , through the separator  102 , and to the anode  116 . This flow of charge, which corresponds to a flow of positive charge, counterbalances the charging flow of current  134  received at the anode  112 , which corresponds to a flow of negative charge. In  FIG. 1 , the flow of charge during charging is indicated by single arrows  118 . 
     Current  134  driven by the electrical power source  122  enables the anode  112  to store ions  116  therein. The anode  112  increasingly resists the charging flow of current  134  as the ions  116  are progressively stored. Thus, storage continues until the anode  112  becomes sufficiently saturated in ions  116  that the voltage potential of the electrical power source  122  is insufficient to maintain the charging flow of current  134 . At this point, the battery  100  may be in a fully-charged state. The switch  128  may then be displaced to establish the open circuit (i.e., to isolate the battery  100 ). 
     To discharge the battery  100 , i.e., to power the electrical load  124 , the switch  128  is displaced to provide electrical continuity for the pathway for discharging  132 . In response, a discharging flow of current  136  travels from the anode  112  to the cathode  110 . The discharging flow of current  136  is driven by a voltage of the battery  100 , which depends on ion transport within the battery  100 . In  FIG. 1 , the discharging flow of current  134  is represented by a double dashed line  134  that has arrows indicating a direction of discharging flow. Concomitantly, ions  116  in the electrolyte  114  flow from the anode  112 , through the separator  102 , and to the cathode  110 . This flow of charge, which corresponds to a flow of positive charge, counterbalances the discharging flow of current  136  received at the cathode  110 , which corresponds to a flow of negative charge. In  FIG. 1 , the flow of charge during discharging is indicated by double arrows  120 . 
     As the cathode  110  progressively saturates in ions  116 , a chemical potential for ion flow within the battery  100  diminishes. Thus, the voltage of the battery  110  decreases notably when the chemical potential is insufficient to drive ion storage in the cathode  110 . As a result, the discharge flow of current  136  decreases and the battery  100  may enter a fully-discharged state. At this point, the switch  128  displaced to establish the open circuit (i.e., to isolate the battery  100 ). 
     It will be appreciated that chemical reactions at the cathode  112  and anode  110  may generate heat within the battery  100 . Moreover, a rate of ion transport during charging and discharging of the battery  100  may influence a rate of heat generation within the battery  100 . The one or more porous materials of the separator  102  may therefore be selected to “shutdown” the battery  100  when a safety threshold, such as a critical operating temperature, has been exceeded. In general, the one or more porous materials of the separator  102  may be selected to establish a shutdown temperature range in which the separator  102  exhibits a high resistance to ion transport. 
     The shutdown temperature range can be bound by a lower temperature limit and an upper temperature limit. The lower temperature limit—which can be a softening temperature of the one or more porous materials—corresponds to an onset of pore collapse within the separator  102 . This pore collapse rapidly chokes off ion transport through the separator  102 . Chemical reactions at the cathode  112  and anode  110  are therefore arrested and the battery  100  “shuts down”. The upper temperature limit corresponds to a breakdown of the separator  102 , which may include melting and chemical decomposition. At the upper temperature limit, ion-transport begins to increase, which may stem from contact between the cathode  112  and the anode  110 . 
     Direct contact can create an internal short through the separator  102  that may greatly accelerate chemical reactions at the cathode  112  and anode  110 . Such acceleration can produce an uncontrolled generation of thermal energy, i.e., a thermal runaway, which is undesirable for the battery  100 . Moreover, pore collapse commonly produces shrinkage in the separator  102  that may bring the cathodes and the anodes closer together (i.e., via thinning). If heat generation persists for a period after pore collapse, the separator  102  may degrade locally around one or more thinned points, risking a loss in dimensional stability, chemical stability, or both. Such losses may increase ion transport and further heat generation. 
     Selection and arrangement of the one or more porous materials, in accordance with embodiments of this disclosure, can improve the shutdown temperature range of the separator  102  thereby enhancing the safety threshold of the battery  100 . Such selection may result in a decrease of the lower temperature limit, and increase of the upper temperature limit, or both. 
     Now referring to  FIG. 2A , a schematic cross-section is presented of a portion of a battery separator  200  in accordance with embodiments of this disclosure. The battery separator  200  may be analogous to the separator  102  described in relation to  FIG. 1 . The battery separator  200  includes a first layer  202  having a first shutdown temperature range, a second layer  204  having a second shutdown temperature range, and a third layer  206  having a third shutdown temperature range. The first shutdown temperature range and the second shutdown temperature range have a first overlap in temperature and the second shutdown temperature range and third shutdown temperature range have a second overlap in temperature. In various embodiments, the first shutdown temperature range and third shutdown temperature range do not overlap. 
     In  FIG. 2A , the first layer  202 , the second layer  204 , and the third layer  206  are depicted in a sequential order and with similar thicknesses. This depiction, however, is for purposes of illustration only and is not intended as limiting. Any order is possible for the first layer  202 , the second layer  204 , and the third layer  206 . Moreover, the first layer  202 , the second layer  204 , and the third layer  206  may exhibit any thickness. In some embodiments, the first layer  202 , the second layer  204 , and the third layer  206  have corresponding thicknesses between 0.3-0.5 micrometers. 
     Non-limiting examples of materials for the battery separator  200  and its layers  202 - 206  are listed in TABLE 1. The listed materials may be either porous or non-porous. TABLE 1 also provides melting temperatures and shutdown ranges for each listed material. It will be understood that TABLE 1 is intended as neither an exhaustive list nor an exclusive list of possible materials. Moreover, the melting temperatures and the shutdown ranges are representative and may vary with unlisted characteristics of each corresponding material (e.g., mean pore size, pore connectivity, volume fraction of pores, volume fraction of crystalline material, hydrocarbon chain length, functional chemical groups, etc.). 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                 Melting  
                 Shutdown  
               
               
                   
                 Material 
                 Temperature 
                 Range 
               
               
                   
                   
               
             
            
               
                   
                 Polyethylene (Low Density) 
                 163° C. 
                 120-220° C. 
               
               
                   
                 Polypropylene (Low Density) 
                 177° C. 
                 140-250° C. 
               
               
                   
                 Polyethylene (High Density) 
                 204° C. 
                 150-250° C. 
               
               
                   
                 Polymethyl methacrylate 
                 218° C. 
                 150-250° C. 
               
               
                   
                 Polyethylene terephthalate 
                 260° C. 
                 150-300° C. 
               
               
                   
                 Polybutylene terephthalate 
                 260° C. 
                 200-300° C. 
               
               
                   
                 Polytetrafluoroethylene 
                 316° C. 
                 250-370° C. 
               
               
                   
                 Polyamide-imide 
                 343° C. 
                 250-450° C. 
               
               
                   
                 Polyetherimide 
                 371° C. 
                 250-450° C. 
               
               
                   
                 Al 2 O 3   
                 2072° C.  
                 2072° C. 
               
               
                   
                   
               
            
           
         
       
     
     In TABLE 1, the shutdown ranges for each material have upper limits higher than the corresponding melting temperatures. Without wishing to be limited to any theory or mode of action, shutdown temperature ranges can be higher than melting temperatures. Factors that can influence shutdown temperature ranges may include, but are not limited to, material chemistry, the molecular weight of materials, the length of functional groups in the materials, interactions between functional groups, and combinations thereof. In various embodiments, higher molecular weight and functional groups can contribute to an increased temperature range. 
     It will be appreciated that one or more materials may be selected for each layer of the battery separator  200  to define a corresponding shutdown temperature range (i.e., the first shutdown temperature range, the second shutdown temperature range, and the third shutdown temperature range). If applicable, this selection may also define an overlap with other shutdown temperature ranges (i.e., the first overlap and second overlap). The one or more materials may be distributed in each layer without restriction. In some embodiments, the first layer  202 , the second layer  204 , the third layer  206 , or any combination thereof, includes a stack of films. In these embodiments, each film in the stack of films corresponds to a single material. In some embodiments, the first layer  202 , the second layer  204 , the third layer  206 , or any combination thereof, include a composite material having one or more secondary materials disposed in a matrix of primary material. 
     In some embodiments, the first shutdown temperature range has a first lower limit from 70-125° C. and a first upper limit from 230-270° C.; the second shutdown temperature range has a second lower limit from 130-170° C. and a second upper limit from 280-320° C.; and the third shutdown temperature range has a third lower limit from 230-270° C. and a third upper limit from 430-470° C. For example, and without limitation, the first shutdown temperature range can span 80-250° C., the second shutdown temperature range can span 150-300° C., and the third shutdown temperature range can span 250-450° C. 
     In some embodiments, the first shutdown temperature range spans 80-250° C. In some embodiments, the first overlap is at least 30° C. In some embodiments, the second overlap is at least 30° C. In some embodiments, the first overlap and the second overlap are at least 30° C. In some embodiments, the battery separator  200  includes a ceramic layer. In further embodiments, the ceramic layer has a melting temperature above 600° C. In these embodiments, the ceramic layer may be an aluminum oxide material (e.g., Al 2 O 3 ). 
     In some embodiments, the first shutdown temperature range, the second shutdown temperature range, the third shutdown temperature range, the first overlap, and the second overlap provide a continuous shutdown range over an expanded range of temperatures. In these embodiments, the continuous shutdown range may be continuously increasing (or decreasing). 
     It will be appreciated that the first layer  202 , the second layer  204 , and the third layer  206  are not limited to single instances within the battery separator  200 . Multiple instances are possible. In some embodiments, the battery separator  200  includes a structure having a symmetrical arrangement of the first layer  202 , the second layer  204 , and the third layer  206  about a center  208 . In these embodiments, the symmetrical arrangement allows the first shutdown temperature range, second shutdown temperature range, and third shutdown temperature range to also be distributed symmetrically about the center  208 .  FIG. 2B  presents a non-limiting example of one possible structure for the battery separator  200 . In this non-limiting example, the first layer  202  incorporates the center  208  of the structure. 
     While the first layer  202 , the second layer  204 , and the third layer  206  are distributed symmetrically about the center  208 , materials forming the first layer  202 , the second layer  204 , and the third layer  206  need not be so. The first layer  202 , the second layer  204 , and the third layer  206  may include any combination of materials that result in the first shutdown temperature range, second shutdown temperature range, and third shutdown temperature range being distributed symmetrically. In further embodiments, such as that shown in  FIG. 2C , a ceramic layer  210  is disposed onto exterior-facing surfaces of the structure. The ceramic layer  210  may share a common ceramic material on each side of the structure, or alternatively, may be formed of different ceramic materials. In  FIG. 2C , the structure is depicted as having ceramic layer  210  formed of the common ceramic material. The ceramic layer  210  may have a melting temperature above 600° C. and may be an aluminum oxide material (e.g., Al 2 O 3 ). 
     According to an illustrative embodiment, a battery separator includes a first layer having a first shutdown temperature range, a second layer having a second shutdown temperature range, and a third layer having a third shutdown temperature range. The second layer is disposed between the first layer and the second layer to create a sandwiched structure. The first shutdown temperature range and the second shutdown temperature range have a first overlap in temperature and the second shutdown temperature range and third shutdown temperature range have a second overlap in temperature. No overlap exists between the first shutdown temperature range and third shutdown temperature range. The first layer, the second layer, the third layer, or any combination thereof, may be formed of materials listed in TABLE 1. 
     In some embodiments, the first shutdown temperature range has a first lower limit from 70-125° C. and a first upper limit from 230-270° C.; the second shutdown temperature range has a second lower limit from 130-170° C. and a second upper limit from 280-320° C.; and the third shutdown temperature range has a third lower limit from 230-270° C. and a third upper limit from 430-470° C. For example, and without limitation, the first shutdown temperature range can span 80-250° C., the second shutdown temperature range can span 150-300° C., and the third shutdown temperature range can span 250-450° C. 
     In some embodiments, the first shutdown temperature range spans 80-250° C. In some embodiments, the first overlap is 20° C. or less. In some embodiments, the second overlap is 20° C. or less. In some embodiments, the first overlap and the second overlap are 20° C. or less. In some embodiments, the battery separator  200  includes a ceramic layer. In further embodiments, the ceramic layer has a melting temperature above 600° C. In these embodiments, the ceramic layer may be an aluminum oxide material (e.g., Al 2 O 3 ). 
     In some embodiments, the first shutdown temperature range, the second shutdown temperature range, the third shutdown temperature range, the first overlap, and the second overlap provide a continuous shutdown range over an expanded range of temperatures. In these embodiments, the continuous shutdown range may be continuously increasing (or decreasing). 
     According to an illustrative embodiment, a battery separator includes a first layer having a first shutdown temperature range of 80-250° C., a second layer having a second shutdown temperature range of 150-300° C., and a third layer having a third shutdown temperature range of 250-450° C. The first layer, the second layer, the third layer, or any combination thereof, may be formed of materials listed in TABLE 1. 
     In some embodiments, the first layer, the second layer, and the third layer having corresponding thicknesses between 0.3-0.5 micrometers. In some embodiments, the first layer includes polyethylene, polypropylene, polyvinyl chloride, or a combination thereof. In some embodiments, the second layer includes polymethyl methacrylate, polybutylene terephthalate, polyethylene terephthalate, or a combination thereof. In some embodiments, the third layer includes polyamide-imide, polyetherimide, polytetrafluoroethylene, or a combination thereof. In some embodiments, the battery separator further includes a ceramic layer selected from the group consisting of an aluminum oxide material, a silicon oxide material, a titanium oxide material, and a zirconium oxide material. 
     In some embodiments, the first shutdown temperature range, the second shutdown temperature range, the third shutdown temperature range, the first overlap, and the second overlap provide a continuous shutdown range over an expanded range of temperatures. In these embodiments, the continuous shutdown range may be continuously increasing (or decreasing). 
     The separators may form part of a battery cell. The battery cell may be a lithium-ion or lithium-polymer battery cell that is used to power a device used in a consumer, medical, aerospace, defense, and/or transportation application. The battery cell can be a jelly roll containing a number of layers which are wound together, including a cathode with an active coating, the separator, and an anode with an active coating. In some aspects, the jelly roll may include one strip of cathode material (e.g., aluminum foil coated with a lithium compound) and one strip of anode material (e.g., copper foil coated with carbon) separated by one strip of separator material (e.g., conducting polymer electrolyte). The cathode, anode, and separator layers may then be wound on a mandrel to form a spirally wound structure. Alternatively, the layers may be stacked and/or used to form other types of battery cell structures, such as bi-cell structures. Such structures are well known in the art. 
     The batteries, components thereof, and various non-limiting components and embodiments as described herein can be used with various electronic devices. Such electronic devices can be any electronic devices known in the art. For example, the device can be a telephone, such as a mobile phone, and a land-line phone, or any communication device, such as a smart phone, including, for example an iPhone®, and an electronic email sending/receiving device. The battery cans, battery assemblies, and various non-limiting components and embodiments as described herein can be used in conjunction with a display, such as a digital display, a TV monitor, an electronic-book reader, a portable web-browser (e.g., iPad®), watch (e.g., AppleWatch), or a computer monitor. The device can also be an entertainment device, including a portable DVD player, conventional DVD player, Blue-Ray disk player, video game console, music player, such as a portable music player (e.g., iPod®), etc. Devices include control devices, such as those that control the streaming of images, videos, sounds (e.g., Apple TV®), or a remote control for a separate electronic device. The device can be a part of a computer or its accessories, laptop keyboard, laptop track pad, desktop keyboard, mouse, and speaker. 
     The above-described methods and processes can be embodied as code and/or data, which can be stored in a computer-readable storage medium as described above. In some embodiments the code and/or data are tangibly embodied on a non-transitory computer-readable storage medium. When a computer system reads and executes the code and/or data stored on the computer-readable storage medium, the computer system performs the methods and processes as they are embodied as the respective code and/or data structures in the computer-readable storage medium. 
     Examples of computer-readable storage medium can include, but is not limited to, volatile memory, non-volatile memory, magnetic and optical storage devices such as disk drives, magnetic tape, CDs (compact discs), DVDs (digital versatile discs or digital video discs), or other media capable of storing code and/or data now known or later developed. 
     Furthermore, methods and processes described herein can be included in hardware circuits or apparatus. These circuits or apparatus may include, but are not limited to, an application-specific integrated circuit (ASIC) chip, a field-programmable gate array (FPGA), a dedicated or shared processor that executes operations embodied in code and/or data structures, as well as other programmable-logic devices now known or later developed. When the hardware modules or apparatus are activated, they perform the methods and processes included within them. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20160915
Publication Date: 20181211
Grant Date: 20181211
Priority Date: 20150930
Inventors: ZENG, Qingcheng
DAFOE, DONALD G.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01M10/4235", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01M50/457", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/451", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/417", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/434", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/489", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/414", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M2/1646", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M2/1653", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M2/1686", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01M50/457", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/451", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/489", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/434", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/417", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/414", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/4235", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y02E60/10", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 64535968