Patent Publication Number: US-2016229282-A1

Title: Thermal management system for vehicles with an electric powertrain

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/923,232, filed on 3 Jan. 2014, the entire contents of which are incorporated herein by reference. This application is related to the U.S. patent application Ser. No. 13/763,636, filed on 9 Feb. 2013, entitled BATTERY SYSTEM WITH SELECTIVE THERMAL MANAGEMENT, which is incorporated by reference herein for all purposes. 
    
    
     BACKGROUND 
     Thermal management is critical to designing and operating electrified vehicles. Various components of vehicles, such as the powertrain [e.g., the engine, transmission, battery system, electric motor(s), motor power electronics, battery power electronics, on-board battery charger, 12V DC-DC converter] and climate control (e.g., cabin heat exchanger, and A/C compressor) components all have, respectively, preferred operating temperature ranges. For these components to function properly, efficiently, or optimally, thermal management systems are required to cool or heat these components appropriately and rapidly. 
     In electrified vehicles which include an internal combustion engine (ICE) (i.e., hybrid vehicles or plug-in hybrid vehicles), two thirds of the heat generated by the engine is typically wasted. While conventional secondary (i.e., rechargeable) batteries are adversely affected when this wasted engine heat is directly absorbed by the battery, certain new secondary batteries, which optimally operate at higher temperatures as compared to those for conventional batteries, can benefit by accepting this wasted heat and being warmed thereby. While conventional thermal management systems exist, systems are still needed to efficiently and rapidly exchange heat between these new secondary batteries and the various components of vehicle that can accept or donate heat energy. As such, there are needs in the field to which the instant invention pertains related to thermal management systems for electric vehicles which include these new secondary batteries as well as to improvements to conventional thermal management systems. 
     The instant disclosure provides, in part, solutions to the aforementioned challenges, as well as others, associated with exchanging heat with secondary batteries and other vehicle components. 
     SUMMARY 
     In one embodiment, set forth herein is a thermal management system for a vehicle with an electric drivetrain. This system includes a battery system including at least one battery cell having a cycle life of at least 100 cycles, and an optimal operating temperature between about 40° C. and 150° C. In some examples, this system includes a battery system including at least one battery cell having a cycle life of at least 100 cycles, and an optimal operating temperature of about 75° C. or higher. In certain examples, this system includes a battery system including at least one battery cell having a cycle life of at least 100 cycles, and an optimal operating temperature above 75° C. In some examples, this system also includes an internal combustion engine (ICE). This system also includes a shared thermal circuit thermally coupling the battery system to other vehicle components, wherein the thermal circuit includes a working fluid, at least one switch or valve for controlling the transfer of the working fluid, wherein a control system actuates the at least one switch or valve, and at least one external heat exchanger; and a control system for controlling the heat exchange between the battery system and these other components of the vehicle. 
     In a second embodiment, set forth herein is a thermal management system for a vehicle with an electric drivetrain. The system includes a control system, a shared thermal circuit comprising a working fluid and one or more switches. In some examples, conductive solids can be substituted for the working fluid, in which case the switches and values open and close the thermal connections to the conductive solids. The one or more switches are configured to operate based on signals received from the control system. The system also includes a battery system having a cycle life of at least 100 cycles and an optimal operating temperature between about 40° C. and 150° C. In some examples, this system includes a battery system including at least one battery cell having a cycle life of at least 100 cycles, and an optimal operating temperature of about 75° C. or higher. In some of these examples, the battery system is thermally coupled to the thermal circuit. Additionally, in some examples, the system includes an internal combustion engine module thermally coupled to the thermal circuit and the battery system via the shared thermal circuit, and at least one external heat exchanger thermally coupled to the thermal circuit. In certain examples, the external heat exchanger may optionally be removed from the thermal circuit. The control system is configured to cause the heat dissipated by the internal combustion engine module to transfer to the battery module through the shared thermal circuit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-B  are simplified diagrams illustrating a thermal management system according to embodiments set forth herein. 
         FIG. 2  is a simplified diagram illustrating an alternative thermal management system according to an embodiment set forth herein. 
         FIGS. 3A-C  are simplified diagrams illustrating a thermal management system in series configuration according to embodiments set forth herein. 
         FIGS. 4A-B  are simplified diagrams illustrating operation of a thermal management system where engine heat is advantageously used by the battery system during cold start according to an embodiment set forth herein. The arrows in  FIG. 4B  illustrate one flow pattern that is possible for this system. Depending on which valves are actuated, other flow patterns are possible. 
         FIGS. 5A-B  are simplified diagrams illustrating operation of a thermal management system where the battery system bypasses the heat exchanger and thermal energy is preserved within the system, according to an embodiment set forth herein. The arrows in  FIG. 5B  illustrate one flow pattern that is possible for this system. Depending on which valves are actuated, other flow patterns are possible. 
         FIGS. 6A-B  are simplified diagrams illustrating operation of a thermal management system where battery system heat is rejected via external exchanger according to an embodiment set forth herein. The arrows in  FIG. 6B  illustrate one flow pattern that is possible for this system. Depending on which valves are actuated, other flow patterns are possible. 
         FIGS. 7A-B  are simplified diagrams illustrating operation of a thermal management system in an electric vehicle according to an embodiment set forth herein. The arrows in  FIG. 7B  illustrate one flow pattern that is possible for this system. Depending on which valves are actuated, other flow patterns are possible. 
         FIGS. 8A-B  are simplified diagrams illustrating operation of a thermal management system with a shared thermal path where climate control module draws heat from various powertrain components according to an embodiment set forth herein. The arrows in  FIG. 8B  illustrate one flow pattern that is possible for this system. Depending on which valves are actuated, other flow patterns are possible. 
         FIGS. 9A-B  are simplified diagrams illustrating thermal management system while disengaged from the heat exchanger module according to an embodiment set forth herein. The arrows in  FIG. 9B  illustrate one flow pattern that is possible for this system. Depending on which valves are actuated, other flow patterns are possible. 
         FIGS. 10A-B  are simplified diagrams of a thermal management system with bidirectional flow control according to an embodiment set forth herein. The arrows in  FIG. 10B  illustrate one flow pattern that is possible for this system. Depending on which valves are actuated, other flow patterns are possible. 
         FIGS. 11A-D  are simplified diagrams illustrating operation of a thermal management system where the thermal loop that includes several powertrain components can be thermally separated into a first thermal path for first group of powertrain components, according to embodiments set forth herein. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments are directed to thermal management systems of electrified vehicles, such as plug-in hybrid electric (PHEV) and electric vehicles (EV; e.g., battery electric vehicles). More specifically, the battery system, one or more additional powertrain components (e.g. including but not limited to the engine, transmission, battery system, electric motor, motor power electronics, battery power electronics, on-board battery charger, 12V DC-DC converter), and/or cabin climate control components (e.g. including but not limited to the cabin heat exchanger, and A/C compressor) of a vehicle share a single thermal circuit or loop. The thermal management system is designed to enable a plurality of components to operate on a single thermal circuit and exchange thermally energy between the battery system, other powertrain components and optionally climate control components as needed. 
     By utilizing a shared thermal circuit with batteries capable of operating at high temperatures (e.g., solid state conversion chemistry batteries or batteries having a solid-state electrolyte), the battery system and, for example, the combustion engine can directly and efficiently be in fluid and thermal communication. In some examples, battery heat can be directly used to warm up a combustion engine, combustion engine heat can be directly used to warm up a battery system (or one or more batteries within a battery system), battery heat can be directly used to provide cabin heat, or all combinations thereof. A single or simple thermal circuit allows for a faster rate of heating and cooling, as less components are needed. Using the systems and methods set forth herein, a second or separate thermal circuit (e.g., including additional heat exchangers, pumps, controllers, and valves, as non-limiting examples) is therefore removed from, or rendered unnecessary for, the system. In some examples, the heat exchanger passively dissipates heat. In yet other examples, the heat exchanger actively removes heat from the system, or battery, in particular, via a heat pump. 
     The batteries set forth herein can operate at a high temperature, thereby allowing novel heat utilization via the shared thermal circuit, set forth in the instant disclosure, between an engine, battery system, transmission, battery system, electric motor(s), motor power electronics, battery power electronics, on-board battery charger, 12V DC-DC converter] and climate control, cabin heat exchanger, and A/C compressor, components and/or other powertrain components. For example, an internal combustion engine (“ICE”) can emit tens of kilowatts of waste heat in operation. By utilizing a shared thermal circuit design according to embodiments set forth herein, waste heat from the combustion engine can be utilized to heat the battery system to its optimal operating temperature range. Similarly, the battery system can utilize the heat radiated from the radiator sized for the combustion engine heat rejection, reducing vehicle cost and improving heat rejection efficiency. 
     In a specific embodiment, a thermal circuit is configured to transfer heat from the ICE to the battery, and vice versa. Heat transfer is accomplished, for example, by using a heat transfer fluid (e.g., typically a water-glycol mixture that has a high specific heat capacity), which is circulated by one or more pumps. For example, the pump is controlled by a controller module, which causes the pump to circulate fluid heated by the ICE to the battery when the ICE has a high temperature and the battery is below a threshold temperature. As a part of the thermal path, switches and/or valves are used to control the flow of the heat transfer fluid. For example, after the battery reaches a desired operating temperature, valves can be used to isolate the combustion engine and battery system to stop heat transfer or dissipate heat to the ambient environment or air. 
     With a single thermal circuit, components (e.g. heat exchanger, pump, heat transfer fluid, and the like) of the thermal circuit are shared, thereby reducing system cost, weight, and volume. In a competitive automotive original equipment manufacturer (OEM) market, reducing system components and saving hundreds of dollars can have significant economic impact. Significant price elasticity exists in the automotive market, where small changes in price can have significant impact on vehicle sales volumes. Consequently, there is a need for automotive OEMs to reduce costs of all vehicle components, especially in instances where system performance can be held constant or improved. For example, the instantly disclosed shared thermal management system, which can modulate the heat of certain or all powertrain components (inclusive of the battery system), is a novel and substantial improvement in vehicle design for vehicles with electrified powertrains. 
     By reducing components such as a heat exchanger, pump, and transfer fluid, more batteries can be assembled in a given volume thus providing more energy and power to a drive train. In some examples, this can increase the driving range. In other examples, this can increase available power with respect to the vehicle&#39;s operating temperature range. 
     The overall weight of the vehicle is reduced, increasing performance and efficiency. The weight of a vehicle can be reduced by about 4 kg, about 8 kg, about 12 kg or about 3-15 kg in total by removing secondary thermal circuit components. In addition to the weight savings, there includes a space savings as well. As much as 15-20 L of space can be reclaimed or utilized when vehicle thermal management systems are designed as set forth herein. The additional space allows for efficient and flexible design of related or unrelated vehicle components. The amount of space reclaimed can be about 5 L, about 10 L, about 15 L or about 4 L-20 L of space, for example. As the battery system is heated more quickly and effectively, performance of the battery system increases. In some examples, the thermal circuits herein heat a battery at least 2-10 times faster than conventional heating systems. Conventional heaters can heat at about 3-5 kW. However, the thermal circuits herein, in some examples, directly heat a secondary battery using the ICE&#39;s dissipated heat at about 10 kW or higher. 
     In addition, a reduced number of components can improve system reliability and reduce maintenance costs. In various embodiments, transfer of waste heat from the engine to the battery module in cold start scenarios reduces or eliminates battery module energy expenditure required for self-warming and can result in a shorter time until the electric drivetrain can take over operation of the vehicle. In various embodiments, a radiator suitable for heat rejection from a combustion engine is oversized relative to the radiator designed solely for a battery system. Consequently, by sharing the radiator, the battery system can utilize enhanced heat rejection capability in the shared system, resulting in increased system efficiency, longer component life, and/or improved vehicle performance. By sharing components and uses thereof, other components can be eliminated or reduced in size as well. 
     Lithium ion and lithium metal batteries are utilized in automotive applications because of their high specific energy and energy density, long cycle life, high round trip efficiency, low self-discharge and long shelf life. However, soaked to cold temperatures that vehicles encounter, lithium ion and lithium metal cells exhibit poor low temperature performance. As an example, it has been reported that lithium ion cells can lose up to 88% of their room temperature capacity at −40° C. The limited power and capacity observed for batteries at low temperatures is particularly problematic for all solid state batteries. 
     Poor low temperature performance, in the worst scenario, can impact vehicle safety where sufficient energy and power from the battery module is not available for driving, e.g. when merging onto a freeway, and in the best scenario, low vehicle performance levels, and/or driver wait times. Consequently, automotive vehicle manufacturers (OEMs) often provide more power and/or capacity than required during most temperature conditions to satisfy low temperature requirements, thereby adding cost, weight, and volume to the powertrain. In certain designs, low performance levels at cold operating temperatures may not be acceptable because they significantly and negatively impact vehicle functionality. In some other designs, the vehicle may rely on the combustion engine (if present) to start and operate the vehicle until the battery module reaches operating temperature, limiting the utility of the electric powertrain. 
     In some examples, set forth herein is a thermal system architecture where the battery system shares the same thermal management circuit with other powertrain components (e.g. including but not limited to the engine, transmission, battery module, electric motor, motor power electronics, battery power electronics, on-board battery charger, 12V DC-DC converter), and/or cabin climate control components (e.g. including but not limited to the cabin heat exchanger, and/or A/C compressor). As an example, the terms “shared thermal circuit”, “combined thermal circuit”, “single thermal loop”, “direct thermal circuit” and “common thermal circuit” refer to a configuration where the heat transfer fluid or heat transfer materials are shared among the battery system and one or more powertrain components (e.g. including but not limited to the engine, transmission, electric motor(s), motor power electronics, battery power electronics, on-board battery charger, 12V DC-DC converter) and/or cabin climate control components (e.g. including but not limited to the cabin heat exchanger, and A/C compressor), of a vehicle. 
     Battery 
     In some examples, set forth herein is a battery system including one or more battery cells connected in series and/or in parallel to provide electrical power to the vehicle. Battery cells of a battery system may or may not be homogenous depending on the design of the battery system. An example of a battery system with different cell types may include cells with high power and/or excellent low temperature performance (e.g. due to a cell chemistry or architecture optimized for power or low temperature) to handle peak power requirement and cold start scenarios together with cells optimized for energy density to enable higher energy capacity. For example, the combinations of primary and boost batteries, set forth in U.S. patent application Ser. No. 13/763,636, filed on 9 Feb. 2013, entitled BATTERY SYSTEM WITH SELECTIVE THERMAL MANAGEMENT, which is incorporated by reference herein for all purposes, are non-limiting examples of battery systems with different cell types. 
     Depending on the implementations, there can be several variations of the thermal system set forth herein that combine the heat transfer circuit of the battery module and the one or more powertrain components (e.g. including but not limited to the engine, transmission, battery module, electric motor, motor power electronics, battery power electronics, on-board battery charger, and/or 12V DC-DC) and/or cabin climate control components (e.g. including but not limited to the cabin heat exchanger, and/or A/C compressor). Because the battery systems set forth herein can not only tolerate, but optimally perform at high temperatures, these battery systems can be thermally coupled in a shared or simple thermal circuit, in a way which would adversely affect the performance of conventional secondary batteries. In some examples, the high temperatures are temperatures above room temperature. In some other examples, the high temperatures are temperatures about 35° C. In other examples, the high temperatures are temperatures about 40° C. In yet other examples, the high temperatures are temperatures about 45° C. In some other examples, the high temperatures are temperatures about 50° C. In some examples, the high temperatures are temperatures about 55° C. In some other examples, the high temperatures are temperatures about 60° C. In some other examples, the high temperatures are temperatures about 65° C. In other examples, the high temperatures are temperatures about 70° C. In yet other examples, the high temperatures are temperatures about 75° C. In some other examples, the high temperatures are temperatures about 80° C. In some examples, the high temperatures are temperatures about 85° C. In some other examples, the high temperatures are temperatures about 90° C. 
     In some examples, set forth herein is a battery system comprising at least one battery cell having a cycle life of at least 100 cycles, and an optimal operating temperature between about 40° C. or higher. In some examples, set forth herein is a battery system comprising at least one battery cell having a cycle life of at least 100 cycles, and an optimal operating temperature between about 50° C. or higher. In some examples, set forth herein is a battery system comprising at least one battery cell having a cycle life of at least 100 cycles, and an optimal operating temperature between about 60° C. or higher. In some examples, set forth herein is a battery system comprising at least one battery cell having a cycle life of at least 100 cycles, and an optimal operating temperature between about 70° C. or higher. In some examples, set forth herein is a battery system comprising at least one battery cell having a cycle life of at least 100 cycles, and an optimal operating temperature between about 75° C. or higher. In some examples, set forth herein is a battery system comprising at least one battery cell having a cycle life of at least 100 cycles, and an optimal operating temperature between about 80° C. or higher. 
     In some examples, the high temperatures are temperatures above room temperature. In some other examples, the high temperatures are temperatures above 35° C. In other examples, the high temperatures are temperatures above 40° C. In yet other examples, the high temperatures are temperatures above 45° C. In some other examples, the high temperatures are temperatures above 50° C. In some examples, the high temperatures are temperatures above 55° C. In some other examples, the high temperatures are temperatures above 60° C. In some other examples, the high temperatures are temperatures above 65° C. In other examples, the high temperatures are temperatures above 70° C. In yet other examples, the high temperatures are temperatures above 75° C. In some other examples, the high temperatures are temperatures above 80° C. In some examples, the high temperatures are temperatures above 85° C. In some other examples, the high temperatures are temperatures above 90° C. 
     The battery systems set forth herein, in some examples, are placed in close proximity, immediately adjacent or in physical contact with components of the thermal circuit, e.g., an internal combustion engine. In some examples, close proximity includes one half the length of an electric vehicle in which the battery and internal combustion engine are located. In some examples, close proximity includes one quarter the length of an electric vehicle in which the battery and internal combustion engine are located. In some examples, close proximity includes one eighth the length of an electric vehicle in which the battery and internal combustion engine are located. In some examples, close proximity includes one tenth the length of an electric vehicle in which the battery and internal combustion engine are located. In some examples, close proximity includes one sixteenth the length of an electric vehicle in which the battery and internal combustion engine are located. In some examples, close proximity includes one twentieth the length of an electric vehicle in which the battery and internal combustion engine are located. In some examples, close proximity includes one thirtieth the length of an electric vehicle in which the battery and internal combustion engine are located. In some examples, close proximity includes less than one half the length of an electric vehicle in which the battery and internal combustion engine are located. In some examples, close proximity includes less than one quarter the length of an electric vehicle in which the battery and internal combustion engine are located. In some examples, close proximity includes less than one eighth the length of an electric vehicle in which the battery and internal combustion engine are located. In some examples, close proximity includes less than one sixteenth the length of an electric vehicle in which the battery and internal combustion engine are located. Merely as an example, shared thermal management systems include, but are not limited to, the following:
         1. A battery system thermal loop combined with thermal loops of one or more of the following: internal combustion engine, transmission, battery module, electric motor(s), motor power electronics, battery power electronics, on-board battery charger, 12V DC-DC, other powertrain components, cabin climate control, and A/C compressor;   2. A thermal loop including a battery module and other powertrain components connected in-series or in parallel; and   3. Components arranged in different order to optimize operation.       

     In some examples, battery cells that are capable of operating at high temperatures are used. High temperature includes operating temperatures from about 80° C. to about 120° C. High temperature includes above 80° C., 80° C. to 100° C., 90-110° C., over 100° C., and about 85-115° C., as examples. In some examples, rechargeable battery cells utilizing a solid state electrolyte capable of operating at high temperatures are implemented as a part of the shared thermal circuit technology. It is to be understood that there may be different types of rechargeable battery cells capable of operating at high temperatures. 
     Examples of solid state electrolytes suitable for use with the disclosure herein include those found in International PCT Patent Application No. PCT/US14/38283, entitled SOLID STATE CATHOLYTE OR ELECTROLYTE FOR BATTERY USING Li A MP B S C  (M=Si, Ge, AND/OR Sn), filed May 15, 2014, the contents of which are incorporated by reference in their entirety. Examples of solid state electrolytes suitable for use with the disclosure herein include those found in International PCT Patent Application No. PCT/US2014/059575, entitled GARNET MATERIALS FOR LI SECONDARY BATTERIES AND METHODS OF MAKING AND USING GARNET MATERIALS, filed Oct. 7, 2014, the contents of which are incorporated by reference in their entirety. Secondary batteries that include these solid state electrolytes are well suited for the thermal management systems set forth herein. 
     Examples of high temperature battery and battery systems suitable for use with the thermal management systems set forth herein include, but are not limited to those found in U.S. Published patent application Ser. No. 13/922,214, entitled NANOSTRUCTURED MATERIALS FOR ELECTROCHEMICAL CONVERSION REACTIONS, and Ser. No. 13/749,706, entitled SOLID STATE ENERGY STORAGE DEVICES, filed on Jun. 19, 2013 and Jan. 25, 2013, respectively. The disclosures of which are herein incorporated by reference in their entirities. Other examples include those found in U.S. Provisional Patent Application No. 62/088,461, entitled CATHODE WITH NANOCOMPOSITE PARTICLE OF CONVERSION CHEMISTRY MATERIAL AND MIXED ELECTRONIC IONIC CONDUCTOR, filed Dec. 5, 2014. Other examples include those found in U.S. Provisional Patent Application No. 62/096,510, entitled LITHIUM RICH NICKEL MANGANESE COBALT OXIDE (LR-NMC), filed Dec. 23, 2014. The contents of these applications are incorporated by reference in their entirety. 
     Solid state conversion chemistry batteries are well suited for use with the thermal management systems set forth herein and often perform well at high temperatures. Some examples of solid state conversion chemistry battteries include transistion metal fluoride batteries. Hybrid conversion chemistry and intercalation batteries are also suitable for use with the thermal management systems set forth herein. 
     In some examples, a positive electrode material can be characterized by particles or nanodomains having a median characteristic dimension of about 20 nm or less. These include (i) particles or nanodomains of a metal selected from the group consisting of iron, cobalt, manganese, copper, nickel, bismuth and alloys thereof, and (ii) particles or nanodomains of lithium fluoride. 
     In one implementation, the metal is iron, manganese or cobalt and the mole ratio of metal to lithium fluoride is about 2 to 8. In another implementation, the metal is copper or nickel and the mole ratio of metal to lithium fluoride is about 1 to 5. In certain embodiments, the metal is an alloy of iron with cobalt, copper, nickel and/or manganese. 
     In certain embodiments, the individual particles additionally include a fluoride of the metal. In some cases, the positive electrode material additionally includes an iron fluoride such as ferric fluoride. For example, the metal may be iron and the particles or nanodomains further include ferric fluoride. 
     In some examples, the positive electrode useful with the high operating temperature batteries and battery cells described herein includes one or more materials selected from conversion chemistry material, such as, but are not limited to, LiF, Fe, Cu, Ni, FeF 2 , FeO d F 3-2d , FeF 3 , CoF 3 , CoF 2 , CuF 2 , NiF 2 , where 0&lt;d&lt;0.5, and the like, materials set forth in U.S. Patent Publication No. 2014/0117291, filed Oct. 25, 2013, and entitled METAL FLUORIDE COMPOSITIONS FOR SELF FORMED BATTERIES, materials set forth in U.S. Provisional Patent Application No. 62/038,059, filed Aug. 15, 2014, entitled DOPED CONVERSION MATERIALS FOR SECONDARY BATTERY CATHODES, materials set forth in U.S. Patent Application Publication No. 2014/0170493, entitled NANOSTRUCTURED MATERIALS FOR ELECTROCHEMICAL CONVERSION REACTIONS, and filed Jun. 19, 2013 as U.S. patent application Ser. No. 13/922,214, and materials such as, but not limited to NCA (lithium nickel cobalt aluminum oxide), LMNO (lithium manganese nickel oxide), NMC (lithium nickel manganese cobalt oxide), LCO (lithium cobalt oxide, i.e., LiCoO 2 ), nickel fluoride (NiF x , wherein x is from 0 to 2.5), copper fluoride (CuF y , wherein y is from 0 to 2.5), or FeF z  (wherein z is selected from 0 to 3.5). 
     The positive electrode material can additionally include (iii) a conductive additive. In some cases, the conductive additive is a mixed ion-electron conductor. In some cases, the conductive additive is a lithium ion conductor. In some implementations, the lithium ion conductor is or includes thio-LISICON, garnet, antiperovskite, lithium sulfide, FeS, FeS 2 , copper sulfide, titanium sulfide, Li 2 S—P 2 S 5 , lithium iron sulfide, Li 2 S—SiS 2 , Li 2 S—SiS 2 —LiI, Li 2 S—SiS 2 —Al 2 S 3 , Li 2 S—SiS 2 —GeS 2 , Li 2 S—SiS 2 —P 2 S 5 , Li 2 S—P 2 S 5 , Li 2 S—GeS 2 —Ga 2 S 3 , or Li 10 GeP 2 S 12 . 
     In some examples of batteries suitable for use with the thermal management systems set forth herein, the positive electrodes can be characterized by the following features: (a) a current collector; and (b) electrochemically active material in electrical communication with the current collector. The electrochemically active material includes (i) a metal component, and (ii) a lithium compound component intermixed with the metal component on a distance scale of about 20 nm or less. Further, the electrochemically active material, when fully charged to form a compound of the metal component and an anion of the lithium compound, has a reversible specific capacity of about 350 mAh/g or greater when discharged with lithium ions at a rate of at least about 200 mA/g. In some cases, the electrochemically active material is provided in a layer having a thickness of between about 10 nm and 300 μm. 
     In some examples of batteries suitable for use with the thermal management systems set forth herein, the positive electrode additionally includes a conductivity enhancing agent such as an electron conductor component and/or an ion conductor component. Some positive electrodes include a mixed ion-electron conductor component. The mixed ion-electron conductor component can contain less than about 30 percent by weight of the cathode. Examples of the mixed ion-electron conductor component include thio-LISICON, garnet, lithium sulfide, FeS, FeS 2 , copper sulfide, titanium sulfide, Li 2 S—P 2 S 5 , lithium iron sulfide, Li 2 S—SiS 2 , Li 2 S—SiS 2 —LiI, Li 2 S—SiS 2 —Al 2 S 3 , Li 2 S—SiS 2 —GeS 2 , Li 2 S—SiS 2 —P 2 S 5 , Li 2 S—P 2 S 5 , Li 2 S—GeS 2 —Ga 2 S 3 , and Li 10 GeP 2 S 12 . In some embodiments, the mixed ion-electron conductor component has a glassy structure. 
     In some examples of batteries suitable for use with the thermal management systems set forth herein, the lithium compound component is selected from lithium halides, lithium sulfides, lithium sulfur-halides, lithium oxides, lithium nitrides, lithium phosphides, and lithium selenides. In one example, the lithium compound component is lithium fluoride. In a further example, the lithium compound component is lithium fluoride and the metal component is manganese, cobalt, copper, iron, or an alloy of any of these. In some positive electrodes, the lithium compound component contains particles or nanodomains having a median characteristic length scale of about 5 nm or less. In certain embodiments, the lithium compound component includes an anion that forms a metal compound with the metal on charge, and the metal compound and lithium ions undergo a reaction to produce the metal and the lithium compound component, and the reaction has a Gibbs free energy of at least about 500 kJ/mol. 
     In some examples of batteries suitable for use with the thermal management systems set forth herein, the batteries are characterized by the following features: (i) an anode, (ii) a solid-state electrolyte, and (iii) a cathode including (a) a current collector, (b) electrochemically active material in electrical communication with the current collector. In these examples, the electrochemically active material includes (i) a metal component, and (ii) a lithium compound component intermixed with the metal component on a distance scale of about 20 nm or less. Further, the electrochemically active material has a reversible specific capacity of about 600 mAh/g or greater when discharged with lithium ions at a rate of at least about 200 mA/g at 50° C. between 1 and 4V versus a Li. 
     In some examples of batteries suitable for use with the thermal management systems set forth herein, the anode, solid state electrolyte, and cathode, together provide a stack of about 1 μm to 10 μm thickness. In some of these designs, the electrochemically active material is provided in a layer having a thickness of between about 10 nm and 300 nm. 
     In some examples, the electrochemically active material has a reversible specific capacity of about 700 mAh/g or greater when discharged with lithium ions at a rate of at least about 200 mA/g. In some examples, the device has an average voltage hysteresis less than about 1V when cycled at a temperature of 100° C. and a charge rate of about 200 mAh/g of cathode active material. 
     In another aspect, the disclosure pertains to battery devices characterized by the following features: (a) an anode region containing lithium; (b) an electrolyte region; (c) a cathode region containing a thickness of lithium fluoride material configured in an amorphous state; and (d) a plurality of iron metal particulate species spatially disposed within an interior region of the thickness of lithium fluoride to form a lithiated conversion material. Further, the battery device has an energy density characterizing the cathode region of greater than about 80% of a theoretical energy density of the cathode region. In certain embodiments, the first plurality of iron metal species is characterized by a diameter of about 5 nm to 0.2 nm. In certain embodiments, the thickness of lithium fluoride material is characterized by a thickness of 30 nm to 0.2 nm. In some cases, the thickness of lithium fluoride material is homogeneous. In certain embodiments, the cathode region is characterized by an iron to fluorine to lithium ratio of about 1:3:3. In certain embodiments, the cathode region is characterized by an iron to fluorine to lithium ratio from about 1:1.5:1.5 to 1:4.5:4.5. 
     In some examples, with the structure described above, the device can have an energy density of between 5 and 1000 Wh/kg, an energy density of between 10 and 650 Wh/kg, or an energy density of between 50 and 500 Wh/kg. In certain embodiment, an energy density can greater than 50 Wh/kg, or greater than 100 Wh/kg. 
     DEFINITIONS 
     As used herein, “control system”, refers to a device, or set of devices, that manages, commands, directs or regulates the behavior of other devices or systems. Control systems include, but are not limited to, a computer, a microprocessor, a microcontroller or a logic circuit, that actuate the valves and switches in the thermal circuit in order to permit the working fluid, therein, to flow in one direction or another direction, or not at all. In certain instances, the microprocessor can be a field programmable gate array (FPGA). Control systems can also include temperature responsive devices (e.g., a thermostat) which sends or receives signals depending on the temperature of the components of the control system or the system controlled by the control system. In some examples, the control system may include a temperature-activated valve apparatus. 
     As used herein, “control module,” refers to an enclosure containing circuit boards preprogrammed with software containing the logic used to determine responses to various sensor inputs. The controller module software has output signals which can actuate pumps or valves at intervals according to its internal logic. 
     As used herein, “heat exchanger”, refers to a device for transferring heat from one medium to another. Examples of heat exchangers include radiators, which can include coils, plates, fins, pipes, and combinations thereof. 
     As used herein, the phrase “battery cell” shall mean a single cell including a positive electrode and a negative electrode, which have ionic communication between the two using an electrolyte. In some embodiments, the same battery cell includes multiple positive electrodes and/or multiple negative electrodes enclosed in one container. 
     As used herein, the phrase “battery system” shall mean an assembly of multiple battery cells packaged for use as a unit. A battery system may include any number of battery cells. These cells may be interconnected using in series connections, parallel connections, and various combinations thereof. 
     As used herein, the phrase “optimal operating temperature,” shall, in the context of a battery cell, mean the temperature at which the battery cell is capable of outputting greater than 50% power of the rated power for the battery cell. In certain examples, the “optimal operating temperature,” shall, in the context of a battery cell, mean the temperature at which the battery cell operates at a peak efficiency while meeting automotive safety and life requirements. 
     As used herein, “fluid”, refers to gases, liquids, gels and combinations thereof. A cooling fluid, or coolant, assists in transferring heat within a thermal circuit. In some examples, a solid conductor may be substituted for a heat transfer fluid. 
     As used herein, “switch”, refers to a device for making and breaking the connection in an electric circuit. 
     As used herein, “thermally coupled”, refers to two or more components or devices in communication, such that they are capable of exchanging (i.e, receiving or dissipating) heat between two or more of the components or devices. Thermally coupled devices can be in close proximity or separated by pipes or other medium for transferring or exchanging heat. 
     As used herein, a “thermal loop,” refers to a circuit including at least a circulating fluid, one or more pumps, a heat exchanger, optionally an electric fluid heater, and optionally valves to control flow. In some examples, the thermal loop optionally includes a port to fill the loop with fluid, and also optionally a reservoir tank. The thermal loop functions to transport and direct heat to or from the battery and, if necessary, reject this heat to another loop or directly to ambient air. 
     As used herein, “powertrain”, refers to one or more of an engine, transmission, battery system, electric motor(s), motor power electronics, battery power electronics, on-board battery charger, and 12V DC-DC converter. 
     As used herein, “dissipate”, refers to dispersing, passively and spontaneously. In some examples here, heat is received or dissipated passively and without energy actively being expended using the thermal management systems set forth herein. 
     As used herein, “drivetrain”, refers to the system in a motor vehicle that connects the transmission to the drive axles. A hybrid vehicle can include an electric drivetrain, for example. 
     As used herein, “conversion chemistry”, refers to a material that undergoes a chemical reaction during the charging and discharging cycles of a secondary battery. For example, a conversion material can include LiF and Fe, FeF 3 , LiF and Cu, CuF 2 , LiF and Ni, NiF 2  or a combination thereof. 
     As used herein, “intercalation chemistry material,” refers to a material that undergoes a lithium insertion reaction during the charging and discharging cycles of a secondary battery. For example, intercalation chemistry materials include LiFePO 4  and LiCoO 2 . In these materials, Li +  inserts into and also deintercalates out of the intercalation material during the discharging and charging cycles of a secondary battery. 
       FIG. 1A  is a simplified diagram illustrating a thermal management system according to an embodiment set forth herein. As shown in  FIG. 1A , the shared thermal management system  100  of a vehicle comprises various components for managing thermal profiles of combustion engine  101  and battery system  105 . For example, the combustion engine  101  can be an internal combustion engine (e.g., gasoline, diesel engine, etc.) or other types of engine, where a large amount of heat is dissipated during operation. In some examples, the internal combustion engine can be substituted for a fuel cell. In some of these examples, fuel cells are selected from cells having a proton exchange membrane (PEM). Typically, a large radiator is needed to dissipate the heat generated by the combustion engine  101 . The battery system  105 , among other features, is configured to power electrical components of the vehicles. In various embodiments, the vehicle is hybrid and relies on both combustion engine  101  and an electric motor (not shown), and the electric motor is at times powered by the battery module  105 . In low temperature (typically around or below freezing), the battery module  105  may have reduced performance. It is common practice in plug-in hybrid electric vehicles for the combustion engine  101  to power the vehicle when the battery module is soaked to a low temperature. The heat dissipated by the combustion engine  101  is transferred to the battery module  105  through a shared thermal path. As shown, the shared thermal circuit comprises pumps  102  and  106 , valves  103 ,  108 ,  107 , and  110 . Additionally, heater  104  and external exchanger  111  are also parts of the shared thermal path. For example, the heater  104  and heater high voltage (HV) switch  109  are implemented with an electrical heater, which is powered by the battery module. The electric heater may be powered by the combustion engine  101  through a motor module that converts the power generated by the combustion engine  101  to electricity for powering the electric heater. Other implementations are possible as well. Heat transfer fluid facilitates heat transfer from the combustion engine  101  to the battery system  105 , and vice versa. For example, in the cold-start scenario described above, heat generated by the combustion engine  101  is absorbed by the heat transfer fluid and pumped by the pump  102  to the battery module  105 . The valves as shown in  FIG. 1A  are connected to a control system. In a cold start scenario, the valves only allow heated fluid to transfer from the combustion engine  101  to the battery module  105 , and the heat transfer fluid bypasses the external heat exchanger in order not to lose thermal energy to the outside environment.  FIG. 1B  shows an embodiment in which the heater  104  (and accompanying switch  109 ) are optional and absent. In some examples, external exchanger  111  can comprise one, two, or more heat exchangers thermally linked, connected, or combined. 
     As mentioned above, the battery system  105  comprises battery cells capable of operating at high temperature. For example, the battery system  105 , with its own significant thermal mass, can provide a heat reservoir to facilitate cooling of the combustion engine  101 , instead of using the external heat exchanger. The method of cooling the combustion engine has the advantage that no external airflow or fans are required, allowing the vehicle to maintain optimum aerodynamic shape. 
     In certain applications, the battery module  105  can be configured to facilitate warming of the combustion engine  101 . For example, the combustion engine  101  may be a diesel engine, which can be challenging to start in low temperature. In certain implementations, the combustion engine  101  may be warmed in advance of operation to reduce emissions and improve performance before operation. In a specific embodiment, the combustion engine  101  may be an internal combustion engine of a plug-in hybrid vehicle. In plug-in hybrid vehicles, the ICE often may not be started when the vehicle is first operated as the battery can provide the energy to power the vehicle for a certain distance (e.g. 10, 20, 30 or more miles). It is to be appreciated that there is a challenge of operating the ICE when it is cold with full performance and meeting all requirements (such as emission standards). In this use case, the battery module  105  warms up to a high temperature while powering the vehicle, and subsequently, while pump  106  is on, valves  107  and  103  are actuated to thermally couple the battery system to the ICE and to pre-warm the combustion engine  101  in advance of its operation. This process allows the engine to start operating at a warmer temperature, reducing emissions and improving performance. Another benefit is reduced wear and tear on the engine. 
     As another example, the same operation can be used by the battery system  302  shown in  FIG. 3A  to obtain cooling by dissipating heat into the engine  306 . Internal combustion engines typically weighs hundreds of pounds, and thus have a high heat capacity. In some use cases, the temperature of the combustion engine  306  may be lower than the temperature of the battery module  302  and lower than ambient temperature. In some examples, so long as the battery is warmer than the ICE, the ICE may be used as a thermal sink. In those cases, battery system  302  can be cooled by transferring heat to the engine  306 , with or without the use of the external heat exchanger  307 . Utilizing the thermal mass of the internal combustion engine  306  for heat removal may be more effective than heat dissipation through the external heat exchanger  307 . 
     Now referring back to  FIG. 1A . The heat generated by the battery system  105  can be used by the climate control module of the vehicle to provide heating for the interior of the vehicle. In addition to the heat dissipation of the combustion engine  101 , the heat dissipated by the battery module  105  can be used for heating the vehicle interior, which is, in some examples, useful when the combustion engine  101  is not operating or in an electric vehicle without a combustion engine, as shown in  FIG. 8A . In some examples, the interior of the car is heated using the waste heat dissipated by the battery. This example is beneficial because it efficiently utilizes wasted heat from the battery as useful heat for the interior of the car. In other examples, the battery is used to power a heater which, in turn, is used to heat the interior of the car. 
     It is to be appreciated that thermal system illustrated in  FIG. 3A  has a shared thermal path, wherein various heat-generating components can transfer heat to one another and to the external heat exchanger using a single thermal path. In certain embodiments, various components shown in  FIG. 3A  can operate at a high temperature (e.g., up to 150° C.). For example, when the ICE operates during hot ambient temperature, the heat transfer fluid (e.g., coolant) can reach over 100° C. before reaching the radiator for heat dissipation. Various components shown in  FIG. 3A  can have different operating temperature ranges. Thus, components in a shared thermal loop may be located specifically so as to match their operating temperatures and optimize the system. While  FIG. 3A  shows only one possible arrangement of components, other configurations are possible (see  FIG. 3C , for example, in which the electric motor  305  and ICE  306  are in direct thermal communication).  FIG. 3B , for example, shows an embodiment in which the heater  301  is optional. In a specific embodiment, the battery system is capable of operating at a temperature of up to about 150° C. 
       FIG. 2  is a simplified diagram illustrating an alternative thermal management system according to an embodiment set forth herein. The thermal management system  200  includes an HV switch  201  that controls the heater  207 . For example, the HV switch is coupled to a control system. The battery module  206  is thermally coupled to the thermal circuit and the components linked thereto by the pump  205 , which pumps heated fluid from the battery module to the combustion engine  202  as needed. It is to be appreciated that the pumps as shown may be implemented using a plurality of pumping devices. For example, multiple pumps devices may be coupled to one another in series to implement the pump  205 . By having more than one pump to carry the pumping function, it provides redundancy in case of pump failure. In addition, the placement of pumps can be configured to reduce the risk of failures. For example, pumps may be positioned before heaters and heat generating components. In a specific embodiment, the pump  203  is placed on the left side of the combustion engine to pump heat transfer fluid to the combustion engine  202 . The valves  204 ,  211 ,  209 , and  210  help control the flow of heat transfer fluid. For example, the valves may be implemented using various types of switches. For example, pump and valve configurations and implementations are described in U.S. patent application Ser. No. 13/428,269, filed 23 Mar. 2013, entitled “Thermal Management System with Dual Mode Coolant Loops”, now U.S. Pat. No. 8,402,776, and published as US 2012-0183815 A1, which is incorporated by reference herein. It is to be appreciated that thermal system illustrated in  FIG. 2  has a shared thermal path, wherein various heat-generating elements can transfer heat to one another using the shared thermal path. 
       FIG. 3A  is a simplified diagram illustrating a thermal management system in series configuration according to an embodiment set forth herein. It is to be appreciated that the system shown in  FIG. 3A  allows the battery system, internal combustion engine, electric motor, motor electronics, and/or optionally other components to share a single thermal system, which includes a heat transfer circuit, a heat exchanger, and a pumping device. As an example, in the embodiment shown in  FIG. 3A , all thermal elements are configured in series. More specifically, the heater  301 , the battery module  302 , pump  303 , motor electronics  304 , electric motor  305 , the combustion engine  306 , and the external heat exchanger  307  are in a series configuration as a part of the thermal circuit. Other arrangements with certain components connected in series and in parallel are possible. It is to be noted that one or more components in the circuit can be configured with a bypass to prevent heating or cooling it. 
       FIG. 4A  is a simplified diagram illustrating operation of a thermal management system where engine heat is used by a battery system according to an embodiment set forth herein. As shown in  FIG. 4A , the combustion engine  401 , the pump  402 , the valve  403 , the heater  404 , the battery module  405 , the pump  407 , and the valve  409  form one of several thermal circuits. In some examples, the heater is not operating. For example, when the battery system is at a low temperature, if the combustion engine  401  is operating, the heat generated by the combustion engine  401  can be transferred to the battery system  405  to warm up the battery cells. As another example, if the battery system  405  is at a high temperature and the combustion engine  401  needs to be heated, the heat is transferred from the battery system  405  to the combustion engine. Depending on the application, the heater  404  can be operating, in which case the heat generated by the heater  404  is used to warm up both the battery system  405  and, optionally, the combustion engine  401 . It is to be appreciated that in this embodiment, the battery system can dissipate heat into the engine as desired to utilize lower temperature working fluid in the engine and/or the engine thermal mass as an alternative to the heat exchanger.  FIG. 4B  illustrates one possible flow pattern, for example. 
       FIG. 5A  is a simplified diagram illustrating operation of a thermal management system without using a heat exchanger according to an embodiment set forth herein. As shown in  FIG. 5A , the battery module  505  is in a closed loop with the heater  504 . For example, the valves  507 ,  510 ,  508  and  503  can be configured to, as needed, disengage thermal coupling between the battery system  505  and the combustion engine  501 . As an example, in this use case heater is turned on, and battery system can be heated using the heater, without any thermal energy being lost to the combustion engine or to the external heat exchanger. In some examples, circulating heat transfer fluid through the battery system via pump  506  as shown in  FIG. 5A , with the heater turned off, equalizes the temperatures of individual cells within the battery system, improving performance and prolonging life of cells in the battery system. It is to be appreciated that other modes of operation are possible as well with the system  500 .  FIG. 5B  illustrates one possible flow pattern, for example. 
       FIG. 6A  is a simplified diagram illustrating operation of a thermal management system where battery module heat is rejected via external exchanger according to an embodiment set forth herein. As shown in  FIG. 6A , the battery module  605  is thermally coupled to the external exchanger  609 . The external exchanger  609  and the battery module  605  are thermally isolated from the combustion engine  601 . It is to be appreciated that other modes of operation are possible as well with the system  600 .  FIG. 6B  illustrates one possible flow pattern, for example. 
       FIG. 7A  is a simplified diagram illustrating operation of a thermal management system in an electric vehicle according to an embodiment set forth herein. It is to be appreciated that, as shown in  FIG. 7A , the battery system, electric motor (optionally), motor electronics (optionally), and/or other component/s are part of a single thermal circuit and could be operated with only a single pump. For example, heat from all components sharing the thermal circuit can be rejected via a single external heat exchanger. There are benefits stemming from such a simplified thermal system enabled by a single thermal circuit for multiple components: utilizing only a single pump, single heat exchanger and a single thermal circuit reduces the number of components in the vehicle, reducing cost, complexity, and volume used in the vehicle.  FIG. 7B  illustrates one possible flow pattern, for example. 
       FIG. 8A  is a simplified diagram illustrating operation of a thermal management system with a shared thermal circuit having a climate control module according to an embodiment set forth herein. In the thermal management system shown in  FIG. 8A , thermal energy from any heat-generating devices, including the battery module, electric motor and motor electronics, is collected in a single thermal circuit that includes a thermal connection to cabin climate control. An advantage of such an arrangement is that heat is collected from all possible sources, maximizing the temperature of the heat transfer fluid when it enters cabin climate control module  811 . This allows fast warm-up of the powertrain components in cold soak conditions and heat transfer to the cabin, improving overall vehicle efficiency. Such a system configuration could be controlled as desired to bypass any devices at a lower temperature in order to collect heat from devices at a temperature above a threshold temperature, in order not to lose heat energy to devices unnecessarily.  FIG. 8B  illustrates one possible flow pattern, for example. 
       FIG. 9A  is a simplified diagram illustrating thermal management system operating in a bypass mode from the heat exchanger module according to an embodiment set forth herein. As shown in  FIG. 9A , when the heat transfer fluid flow bypasses the external heat exchanger  909 , the thermal management system has the advantage that heat from all the components in the circuit, such as the electric motor  905 , motor electronics  907  and other heat-releasing components can be used to warm up the battery system  903 . Alternatively, heat from the battery system  903  could warm up the motor electronics  907  and/or electric motor  905 . Another benefit of such an arrangement is that temperature is naturally equalized between all the devices in the thermal circuit.  FIG. 9B  illustrates one possible flow pattern, for example. 
       FIG. 10A  is a simplified diagram illustrating operation of a thermal management system with bidirectional flow control according to an embodiment set forth herein. As shown in  FIG. 10A , the thermal management system, in some examples, has a plurality of pumps arranged such that the flow of the heat transfer fluid is bidirectional, or a single pumping device capable of pumping in both directions. Depending on the implementation, the embodiment can have several advantages over uni-directional pumping: heat can be transferred from battery system to the motor (and/or other components in the circuit) if the battery system is at an elevated temperature or from the motor (or other components in the circuit) to the battery system, if desired. Another benefit of bi-directional flow includes improved thermal management of battery system. Battery cells typically suffer premature degradation because heat is rejected preferentially from a single side of the battery system, due to flow from a single direction. The ability to reverse the flow allows for even cooling of each side of the battery system, prolonging life of the battery system. It is to be appreciated that in a thermal system circuit with a single external heat exchanger and without additional heat-accepting devices, the thermal fluid typically has the lowest temperature immediately after flowing through the heat exchanger. Another benefit of the bi-directional operation is that either of the devices thermally adjacent to the heat exchanger can be selectively cooled with the lowest temperature heat transfer fluid, maximizing the effectiveness of the cooling system.  FIG. 10B  illustrates possible flow patterns, for example. 
       FIG. 11A  is a simplified diagram illustrating a thermal management system where one group of powertrain components can be thermally separated from a second group of components according to an embodiment set forth herein. In some examples, that components shown in  FIG. 11A  have different operating temperature ranges. In certain examples, electric motor and motor electronics may operate at temperature ranges lower than ICE and/or battery system. In some examples, components operating at a relatively low temperature range are thermally coupled to one another in a “low-temperature” thermal loop, and the components operating at relatively high temperature range are thermally to one another in a “high-temperature” thermal loop. In some examples, a control system determines whether to merge operation back into a single thermal circuit.  FIG. 11C  shows an alternate component arrangement, as an example. In  FIG. 11A , the thermal management system includes of a thermal circuit which can be thermally separated into a first thermal path for first group of powertrain components (i.e. battery system  1101  and internal combustion engine  1113 ) and second thermal path for second group of powertrain components (i.e. electric motor  1104  and inverter  1105 ) according to an embodiment set forth herein. The thermal separation may be achieved by control of valves such as  1102 ,  1103 ,  1106  and  1109 .  FIGS. 11B and 11D  show options without a heater. These arrangements have the advantage that most or all of the powertrain components can be thermally managed with a single thermal circuit, but can also be thermally separated in conditions where different thermal properties (i.e. temperature) are needed for different components. One potential beneficial use case is that when combustion engine is off, all the powertrain components are cooled with a single loop. If the combustion engine is turned on, and the temperature of the thermal fluid in the circuit rises above a predetermined threshold, components that require a lower operating temperature can be thermally disconnected from the loop. 
     In some examples, set forth herein is a thermal management system for a vehicle with an electric drivetrain. In these examples, the system includes a battery system having at least one battery cell. In some examples, the battery cell has, in some examples, a cycle life of at least 100 cycles. In certain examples, the battery cell has an optimal operating temperature of about 40° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 45° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 50° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 55° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 60° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 65° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 70° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 75° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 80° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 90° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 100° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 105° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 110° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 115° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 120° C. or higher. In certain examples, the battery cell has an optimal operating temperature of about 125° C. or higher. 
     In some of the above examples, the system also includes an internal combustion engine (ICE). 
     In some of the above examples, the system also includes a shared thermal circuit thermally coupling the battery system and the ICE, including a working fluid, at least one switch or valve for controlling the transfer of the working fluid, and at least one external heat exchanger. 
     In some of the above examples, the system also includes a control system for controlling the heat exchange between the ICE and the battery system, wherein the control system actuates the at least one switch or valve. 
     As illustrated in  FIG. 1A , in some examples, the system includes a battery system  105  in serial connection with a pump  106  and a heater  104 . In some of these examples, the battery system can be warmed by the heater. In some of these examples, the battery can power the heater. In some other examples, an ICE can power the heater which can warm the battery system  105 . In some examples, a heat exchanger can be serially connected to the battery, depending on the valves actuated (e.g.,  107  and  110 ) in order to exchange heat from the battery system  105  or from the ICE  101 . Depending on the valves which are actuated (e.g.,  107 ,  108 ,  103 , and  110 ), the working fluid can be circulated between the ICE  101  and the battery system  105  or optionally also to the external exchanger. 
     As illustrated in  FIG. 1B , in some examples, the system does not include heater  104  but does include the aforementioned components. 
     As illustrated in  FIG. 3A, 3B , or  3 C, in some examples, the ICE  306 , electric motor  305 , and motor electronics  304  can be serially connected within the thermal circuit. In some examples, the working fluid that contacts the battery system can be transferred to or from the ICE  306 , electric motor  305 , and motor electronics  304  depending on the valves (V) which are activated and depending on the operation of pump  303 . 
     As illustrated in  FIG. 4B , in some examples, the working fluid can be transferred from the battery system  405  to the ICE  401  without contacting the external exchanger  411 . In some other examples, valves  409  and  410  can be actuated to also allow the working fluid to contact the external exchanger. 
     As illustrated in  FIG. 5B , in some examples, the working fluid can be circulated around the battery system  505  but without contacting the external exchanger  505  or the ICE  501 , depending on the operation of pump  506  and valves  507  and  510 . 
     As illustrated in  FIG. 6B , in some of the above examples, the working fluid can also be circulated through the external exchanger  609  depending on the actuation of valve  610 . 
     As illustrated in  FIG. 8B , in some of the thermal management systems described here, such as the system of  FIG. 8A , the working fluid can also be circulated through the battery system  803 , motor electronics  805 , electric motor  806 , cabin climate control  811  but not through the external exchanger  809 . 
     As illustrated in  FIG. 9B , in some of the thermal management systems described here, such as the system of  FIG. 9A , the working fluid can be circulated through the battery system  903 , motor electronics  907 , electric motor  905 , cabin climate control  811  but not through the external exchanger  909 . 
     As illustrated in  FIG. 10B , in some of the thermal management systems described here, such as the system of  FIG. 10A , the working fluid can also be circulated in a bi-directional flow pattern through a battery system  1001 , at least one or more pumps, motor electronics  1005 , electric motor  1007 , combustion engine  1009 , and external exchanger  1011 . 
     As illustrated in  FIG. 11A , in some examples, the thermal management systems includes a battery system  1101  on a thermal loop that also includes an ICE  1113  and which is separate from a thermal loop that includes the motor electronics  1105  and electric motor  1104 . Depending on the actuation of valves  1103 ,  1102 ,  1109 , or  1106 , these components can be thermally isolated or thermally coupled with each other. As illustrated in  FIG. 11B , in some examples, the heater is not included in the thermal management system. As illustrated in  FIG. 11C , in some examples, the thermal management systems includes a battery system  1101  on a thermal loop that also includes the motor electronics  1105  and electric motor  1104  and which is separate from a thermal loop that includes an ICE  1113 . Depending on the actuation of valves  1103 ,  1102 ,  1109 , or  1106 , these components can be thermally isolated or thermally coupled with each other. As illustrated in  FIG. 11D , in some examples, the heater is not included in the thermal management system. 
     Examples 
     Conventional Plug-in Hybrid Electric Vehicle (PHEV) Example 
     In one example, a PHEV with an 85 hp (63 kW) internal combustion engine, 120 kW electric motor, and a 16 kWh battery system was used. The internal combustion engine and battery system were each on separate thermal management loops each including a pump and radiator. 30 kW of drive power was employed, in which the internal combustion engine had a 33% rejection rate of heat into the coolant loop (i.e. 10 kW at 30 kW drive power). The battery system thermal management loop also featured a 5 kW heater. 
     The 16 kWh battery system featured lithium ion cells that have a gravimetric energy density of 200 Wh/kg and a total cell weight of 80 kg. Cell specific heat capacity was 1 KJ/kg ° C. Cell &amp; module heat capacity was 106 KJ/° C. 
     The pump for this independent battery thermal management loop weighed 1 kg, took up 1.5 L of space, and cost $100. The radiator for the independent battery thermal management loop weighed 0.5 kg, took up 3.5 L of space, and cost $75. The heater for the battery thermal management loop weighed 7 kg, took up 10 L of space, and cost $100. 
     A −10° C. cold soak was used for the battery system and the internal combustion engine operated the car until the battery system was at 90% of cell power capability. The 5 kW heater warmed the battery modules to −20° C. in approximately 10 minutes, enabling 90% of the cells peak power rating. Heating in the above example off the electric heater alone consumed 3000 kJ or 0.8 kWh of system energy. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                   
                 Heating Time 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 1 
                 10 
                 30 
                 1 
                 2 
                 5 
                 10 
               
               
                   
                 second 
                 seconds 
                 seconds 
                 minute 
                 minutes 
                 minutes 
                 minutes 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Typical Li-Ion cells: 
                   
                   
                   
                   
                   
                   
                   
               
               
                 Heater Energy Output (kJ) 
                 5  
                 50   
                 150   
                 300   
                 600   
                 1500    
                 3000    
               
               
                 Cell Temperature Increase (degrees Celsius) 
                  0.05 
                  0.47 
                  1.41 
                  2.82 
                  5.64 
                  14.10 
                  28.20 
               
               
                 Battery System Temperature (deg C.) 
                 −10.0  
                 −9.5 
                 −8.6 
                 −7.2 
                 −4.4 
                   4.1 
                 18.2 
               
               
                 Approximate Battery System Rate Capability  
                 18% 
                 18% 
                 18% 
                 20% 
                 25% 
                 45% 
                 90% 
               
               
                 (% of peak) 
                   
                   
                   
                   
                   
                   
                   
               
               
                 Battery System Power Capability (kW) 
                 21.6 
                 21.6 
                 21.6 
                 24   
                 30   
                 54   
                 108   
               
               
                   
               
            
           
         
       
     
     Shared Thermal Management PHEV Example 
     In a second example, a PHEV with an 85 hp (63 kW) internal combustion engine, 120 kW electric motor, and a 16 kWh battery system was used. The internal combustion engine and battery system were on a shared thermal management loop as described in this disclosure. 
     The 16 kWh battery system featured lithium ion cells that have a gravimetric energy density of 200 Wh/kg and a total cell weight of 80 kg. Cell specific heat capacity was 1 KJ/kg ° C. Cell &amp; module heat capacity was 106 KJ/° C. 
     With this implementation of the shared thermal management system compared to the conventional example, no independent pump or radiator was required for the battery system. Furthermore, no heater was required. Consequently, this saves an aggregate 8.5 kg, 15 L of space, and $275 of cost. Expressed per kWh of battery system, this cost savings was about $17/kWh. 
     A −10° C. cold soak was used for the battery system with the internal combustion engine operating the car until the battery system was at 90% of cell power capability, the 10 kW of “waste heat” from the internal combustion engine was transferred via the shared thermal management loop to warm the battery modules to −20° C. in approximately 5 minutes, enabling 90% of the cells peak power rating. Relative to the “conventional PHEV” example above, the warm time to 90% of cell power capability was achieved in half the time (i.e. 5 minutes faster) and without the expenditure of 0.8 kWh of battery system capacity (5% of system capacity) which at 250 Wh/mile represents 3.3 miles of electric range. 
     
       
         
           
               
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                   
                 Heating Time 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 1  
                 10  
                 30  
                 1  
                 2  
                 5  
               
               
                   
                 second 
                 seconds 
                 seconds 
                 minute 
                 minutes 
                 minutes 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Typical Li-Ion cells: 
                   
                   
                   
                   
                   
                   
               
               
                 Cumulative ICE Heat Rejected into Coolant (kJ) 
                 10   
                 100   
                 300   
                 600   
                 1200    
                 3000    
               
               
                 Cell Temperature Increase (degrees Celsius) 
                  0.09 
                  0.94 
                  2.82 
                  5.64 
                  11.28 
                  28.20 
               
               
                 Battery System Temperature (deg C.) 
                 −9.9 
                 −9.1 
                 −7.2 
                 −4.4 
                   1.3 
                 18.2 
               
               
                 Approximate Battery System Rate Capability  
                 18% 
                 18% 
                 18% 
                 25% 
                 40% 
                 90% 
               
               
                 (% of peak) 
                   
                   
                   
                   
                   
                   
               
               
                 Battery System Power Capability (kW) 
                 21.6 
                 21.6 
                 21.6 
                 30   
                 48   
                 108   
               
               
                   
               
            
           
         
       
     
     The above description is presented to enable one of ordinary skill in the art to make use of disclosures herein and to incorporate them in the context of particular applications. Various modifications, as well as a variety of uses in different applications will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to a wide range of embodiments. Thus, the disclosure set forth herein is not intended to be limited to the embodiments presented, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. 
     It is to be appreciated that embodiments set forth herein provide numerous advantages over existing technologies. Examples of improvements include but are not limited to reduced component costs, lower weight, lower volume, higher reliability, longer life, higher performance, higher efficiency, and a reduction in complexity. There are other benefits as well.