Patent Publication Number: US-2023156869-A1

Title: Systems and methods for facilitating heating of an item

Description:
BACKGROUND 
     Statement of the Technical Field 
     The present document concerns heating systems. More specifically, the present document concerns systems and methods for facilitating heating of item(s). 
     Description of the Related Art 
     Insulated bags are often used to facilitate the delivery of food items from a restaurant to a customer location. The insulated bags are waterproof bags made with various materials like nylon, vinyl or other exterior layer designed to keep the food items properly heated and/or chilled during transit. The insulated bags have limitations and challenges. For example, the insulation bags may not be airtight which results in heat loss from the food items and are absent of any heat generation functionality. 
     SUMMARY 
     This document concerns systems and methods for providing and/or operating a heating pad. The heating pad comprises: a first heating fabric comprising graphene; a nanotube-based film having a first surface coupled to the first heating fabric; a second heating fabric coupled to a second opposing surface of the nanotube-based film (which may be graphene based or may be absent of any graphene); and a flexible circuit disposed between the first heating fabric and the nanotube-based film. The flexible circuit is configured to facilitate an increase in temperature by the first heating fabric and/or second heating fabrics. 
     The first heating fabric layer can include, but is not limited to, a monolayer of carbon atoms connected to each other via sp 2  hybridization to form a planar two-dimensional hexagonal honeycomb lattice structure. The nanotube-based film can include, but is not limited to, a carbon nanotube film. The second heating fabric layer can include, but is not limited to, a carbon fiber paper, a carbon fiber cloth and/or a graphite fiber cloth. The heating pad may be configured to: convert at least a given amount (e.g., ≥50% or 75%) of electric energy into heat energy; have a radiation efficiency of at least a given amount (e.g., ≥50% or 70%); and/or operate with a voltage less than or equal to a given voltage (e.g., 36 Volts). The heating pad may be flexible and washable without affecting physical and electrical properties of the heating pad. The heating pad may be configured to: reach 140° F. in less than or equal to sixty seconds; reach 200° F. in less than or equal to one hundred eighty seconds; and/or experience a difference or rise in temperature within three seconds of power being supplied thereto. 
     The flexible circuit may comprise a flexible battery (e.g., a graphene battery) or the flexible circuit may be energized by a flexible battery. The flexible circuit may alternatively or additionally comprise a first conductive line portion and a second conductive line portion which are separately supplied power from a power source at the same time. The first and second conductive line portions may be designed and positioned relative to each other such that heat radiation is emitted uniformly across exposed surfaces of the heating pad. The first and second conductive line portions may partially overlap each other while being electrically isolated from each other. For example, the first conductive line portion may comprise a plurality of first fingers. At least one of the first fingers resides between a plurality of second fingers of the second conductive line portion. At least one of the second fingers resides between the plurality of fingers of the first conductive line portion. 
     In some scenarios, the flexible circuit may also comprise a cable connected to the first and second conductive lines and a controller removably connected to the cable. The controller may be configured to allow a user to selectively control an amount of current supplied to the first and second conductive lines from a power source. The power source may be external to the heating pad and comprise a graphene battery, a flexible graphene battery or an external energy source. The controller may be configured to facilitate wireless communications between the heating pad and an external communication device for remotely controlling operations of the heating pad. Additionally or alternatively, the flexible circuit may be configured to facilitate wireless communications between the heating pad and an external communication device for remotely controlling operations of the heating pad. 
     The flexible circuit may further comprise a flexible sensor and be configured to cause the heating pad to transition operational modes based on sensor data generated by the flexible sensor. The operational modes can include, but are not limited to, an off mode, an on mode, a low heat mode, a medium heat mode, and/or a high heat mode. The flexible sensor can include, but is not limited to, a pressure sensor, a temperature sensor, a location sensor, a proximity sensor, a sound sensor, and/or a camera. 
     In those or other scenarios, the heating pad is at least partially encompassed by a flexible output device. The flexible output device can include, but is not limited to, a light strip, an audio device and/or a vibration device. 
     The present document also concerns systems and methods for providing and operating a portable electric heater. The portable electric heater comprises: a controller configured to control a temperature setting of the portable electric heater; and a heating pad communicatively coupled to the controller. The heating pad comprises a plurality of material layers arranged in a stack. The material layers comprise: a first heating fabric comprising graphene; a nanotube-based film having a first surface coupled to the first heating fabric; a second heating fabric coupled to a second opposing surface of the nanotube-based film; and a flexible circuit disposed between the first heating fabric and the nanotube-based film. The flexible circuit is configured to facilitate an increase in temperature by at least the first and second heating fabrics. 
     The present document further concerns systems and methods for providing a product with a heating capability. The product can include, but is not limited to, an insulative bag (e.g., for use in the food industry), a piece of clothing (e.g., a shirt, shorts, pants, jacket, etc.), footwear (e.g., boots, insoles for shoes, etc.), bedding (e.g., sheet, blanket, pillow, etc.), a medical apparatus (e.g., back brace, etc.), furniture (e.g., a massage chair, coach, etc.), wellness industry (e.g., spa beds, spa mats, massage equipment, etc.) sports &amp; fitness industry (e.g., gym equipment, gym gears, pain relief heating pads, yoga mat, etc.) and/or other item (e.g., a car seat, steering wheel, etc.). The product comprises a main body; and a heating pad disposed on the main body or in a pocket of the main body. The heating pad can be the same as or similar to the heating pad described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       This disclosure is facilitated by reference to the following drawing figures, in which like numerals represent like items throughout the figures. 
         FIG.  1    provides a top view of an illustrative electric heater. 
         FIG.  2    provides a perspective view of the electric heater shown in  FIG.  1   . 
         FIG.  3    provide an illustration showing a heating pad of the electric heater of  FIG.  1    in a bent or folded position. 
         FIG.  4    provides an illustration showing a layer stack for the heating pad of  FIGS.  1 - 3   . 
         FIG.  5    provides an illustration showing a structure of the first heating fabric layer of  FIG.  4   . 
         FIG.  6    provides an illustration showing a uniformity of thermal radiation emitted from the first heating fabric layer with an increased temperature. 
         FIG.  7    provides a graph illustrating that the heating fabric layer(s) has(have) a relatively high electric energy-to-heat conversion rate and thermal radiation efficiency as compared to that of other layers of the heating pad. 
         FIG.  8    provides an illustration that is useful for understanding the washability and durability of the electric heater and/or the first heating fabric layer. 
         FIG.  9    provides a graph showing a rise in temperature of the electric heater in a given environment. 
         FIG.  10 A- 10 F  (collectively referred to as “ FIG.  10   ”) show the electric heater being used in various products. 
         FIG.  11    provides a top view of the nanotube-based film layer and conductive layer of the heating pad connected to a controller. 
         FIG.  12    provides an exploded view of the heating pad. 
         FIGS.  13 A-B  (collectively referred to as “ FIG.  13   ”) provides top views of other conductive layer architectures along with flexible sensors. 
         FIG.  14    provides a perspective view of a controller that can be used. 
         FIG.  15    provides a perspective view of a power supply that can be used to power the electric heater. 
         FIG.  16    provides an illustration of a computing device. 
         FIG.  17    provides a flow diagram of an illustrative method for making a graphene cloth or fabric from a graphene slurry. 
         FIG.  18    provides a flow diagram of an illustrative method for making a heating pad. 
         FIGS.  19 - 21    provide illustrations of various heating pad architectures. 
     
    
    
     DETAILED DESCRIPTION 
     It will be readily understood that the solution described herein and illustrated in the appended figures could involve a wide variety of different configurations. Thus, the following more detailed description, as represented in the figures, is not intended to limit the scope of the present disclosure but is merely representative of certain implementations in different scenarios. While the various aspects are presented in the drawings, the drawings are not necessarily drawn to scale unless specifically indicated. 
     Reference throughout this specification to features, advantages, or similar language does not imply that all the features and advantages that may be realized should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussions of the features and advantages, and similar language, throughout the specification may, but do not necessarily, refer to the same embodiment. 
     Reference throughout this specification to “one embodiment”, “an embodiment”, or similar language means that a particular feature, structure, or characteristic described in connection with the indicated embodiment is included in at least one embodiment of the present solution. Thus, the phrases “in one embodiment”, “in an embodiment”, and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
     As used in this document, the singular form “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. As used in this document, the term “comprising” means “including, but not limited to”. 
     As noted above, insulated bags are often used to facilitate the delivery of food items from a restaurant to a customer location (e.g., house or place of employment). The insulated bags are waterproof bags made with a nylon or vinyl exterior layer designed to keep the food items properly heated and/or chilled during transit. The insulated bags have limitations and challenges. For example, the insulated bags may not be airtight which results in heat loss from the food items and are absent of any heat generation functionality to re-warm the foot items. 
     The present solution provides a means to overcome these drawbacks of insulated bags. In this regard, the present solution concerns a portable electric heater comprising a flexible heating pad with layer(s) of graphene fabric. The graphene fabric is designed and engineered using advance material science. The electric heater can be integrated in an insulated bag to facilitate the heating of items disposed on or inside the insulated bag (e.g., in a cavity or pocket). The electric heater may be configured to generate heat from, for example, 40° C. (104° F.) to 130° C. (266° F.). This temperature range allows various types of food items to be keep warm in the insulated bag at respectively optimal temperature(s). The circuit components of the electric heater are flexible, rugged and operationally efficient. Wireless communication technology may be integrated with the electric heater such that a user thereof can remotely control operations of the electric heater via software application(s) running on a mobile device (e.g., a smart phone) or from a remote system (e.g., a cloud based system). The wireless communication technology can include, but is not limited to, WiFi and Bluetooth. The heating pad is rugged, washable and durable. 
     Although the present solution is described herein in relation to the insulated bag and food industry applications, the present solution is not limited in this regard. The electric heater of the present solution can be used in other applications such as clothing applications (as shown in  FIG.  10 A ), footwear applications, smart gear applications (as shown in  FIG.  10 C ), bedding applications (as shown in  FIG.  10 D ), pillow applications (as shown in  FIG.  10 D ), furniture applications, automobile application (e.g., car seats as shown in  FIG.  10 F ), wellness industry applications, sports &amp; fitness industry applications, and/or medical applications (e.g., as pain relief pads as shown in  FIG.  10 E ). 
     Thus, this document concerns systems and methods for providing and/or operating a heating pad. The heating pad comprises: a first heating fabric comprising graphene; a nanotube-based film having a first surface coupled to the first heating fabric; a second heating fabric coupled to a second opposing surface of the nanotube-based film; and a flexible circuit disposed between the first heating fabric and the nanotube-based film, the flexible circuit configured to facilitate an increase in temperature by at least the first and second heating fabrics. 
     The first heating fabric layer can include, but is not limited to, a monolayer of carbon atoms connected to each other via sp 2  hybridization to form a planar two-dimensional hexagonal honeycomb lattice structure. The nanotube-based film can include, but is not limited to, a carbon nanotube film. The second heating fabric layer can include, but is not limited to, a carbon fiber paper, a carbon fiber cloth and/or a graphite fiber cloth. The heating pad may be configured to: convert at least a given amount (e.g., &gt;50% or 75%) of electric energy into heat energy; have a radiation efficiency of at least a given amount (e.g., &gt;50% or 70%); and/or operate with a voltage less than or equal to a given voltage (e.g., 36 Volts). The heating pad may be flexible and washable without affecting physical and electrical properties of the heating pad. The heating pad may be configured to: reach 140° F. in less than or equal to sixty seconds; reach 200° F. in less than or equal to one hundred eighty seconds; and/or experience a difference or rise in temperature within three seconds of power being supplied thereto. 
     The flexible circuit may comprise a flexible battery (e.g., a graphene battery) or the flexible circuit may be energized by a flexible battery. The flexible circuit may alternatively or additionally comprise a first conductive line portion and a second conductive line portion which are separately supplied power from a power source at the same time. The first and second conductive line portions may be designed and positioned relative to each other such that heat radiation is emitted uniformly across exposed surfaces of the heating pad. The first and second conductive line portions may partially overlap each other while being electrically isolated from each other. For example, the first conductive line portion may comprise a plurality of first fingers. At least one of the first fingers resides between a plurality of second fingers of the second conductive line portion. At least one of the second fingers resides between the plurality of fingers of the first conductive line portion. 
     In some scenarios, the flexible circuit may also comprise a cable connected to the first and second conductive lines and a controller removably connected to the cable. The controller may be configured to allow a user to selectively control an amount of current supplied to the first and second conductive lines from a power source. The power source may be external to the heating pad and comprise a graphene battery or any other powers source. The controller may be configured to facilitate wireless communications between the heating pad and an external communication device for remotely controlling operations of the heating pad. Additionally or alternatively, the flexible circuit may be configured to facilitate wireless communications between the heating pad and an external communication device for remotely controlling operations of the heating pad. 
     The flexible circuit may further comprise a flexible sensor and be configured to cause the heating pad to transition operational modes based on sensor data generated by the flexible sensor. The operational modes can include, but are not limited to, an off mode, an on mode, a low heat mode, a medium heat mode, and/or a high heat mode. The flexible sensor can include, but is not limited to, a pressure sensor, a temperature sensor, a location sensor, a proximity sensor, a sound sensor, and/or a camera. 
     In those or other scenarios, the heating pad is at least partially encompassed by a flexible output device. The flexible output device can include, but is not limited to, a light strip, an audio device and/or a vibration device. 
     The present document also concerns systems and methods for providing and operating a portable electric heater. The portable electric heater comprises: a controller configured to control a temperature setting of the portable electric heater; and a heating pad communicatively coupled to the controller. The controller comprises a plurality of material layers arranged in a stack. The material layers comprise: a first heating fabric comprising graphene; a nanotube-based film having a first surface coupled to the first heating fabric; a second heating fabric coupled to a second opposing surface of the nanotube-based film; and a flexible circuit disposed between the first heating fabric and the nanotube-based film. The flexible circuit is configured to facilitate an increase in temperature by at least the first and second heating fabrics. The features of the heating pad can be the same as or similar to those described above. 
     The present document further concerns systems and methods for providing a product with a heating capability. The product can include, but is not limited to, an insulative bag (e.g., for use in the food industry), a piece of clothing (e.g., a shirt, shorts, pants, jacket, etc.), footwear (e.g., boots, insoles for shoes, etc.), bedding (e.g., sheet, blanket, pillow, etc.), a medical apparatus (e.g., back brace, etc.), furniture (e.g., a massage chair, coach, etc.), wellness industry (e.g., spa beds, spa mats, massage equipment, etc.) sports &amp; fitness industry (e.g., gym equipment, pain relief heating pads, yoga mats, etc.) and/or other item (e.g., a car seat, steering wheel, etc.). The product comprises a main body; and a heating pad disposed on the main body or in the main body (e.g., in a pocket or cavity of the main body). The heating pad can be the same as or similar to the heating pad described herein. 
     Referring now to  FIG.  1   , there is provided a top view of an illustrative electric heater  100  in accordance with the present solution. A side perspective view of the electric heater  110  is provided in  FIG.  2   . The electric heater  110  overcomes many drawbacks of convention electric heaters and/or heating pads. For example, the electric heater  110  has a relatively faster heating speed (i.e., needs less time to heat once powered, e.g., ≤60 seconds to heat), uniform heating across its surfaces, a relatively high electric-heat conversion rate (e.g., ≥20%, 30%, 40%, 50%, 60%, 70% or 75%) electric energy is converted into heat energy), an improved heat radiation efficiency (e.g., ≥20%, 30%, 40%, 50%, 60% or 70%), a relatively lower superconductivity (e.g., leads to higher efficiency), a reduced probability of circuit failure, a relatively longer service life (e.g., ≥5000 hours), an improved tensile strength, and/or an improved washing stability (i.e., the heating functionality does not degrade when the heating pad is washed). The electric heater  110  is also configured to operate with relatively lower voltages (e.g., ≤36 V) which are human body safe voltages. 
     As shown in  FIG.  1   , the electric heater  100  is a portable device that can be used separate from or in conjunction with a product  150 . The product can include an insulted bag or other an article of manufacture (e.g., clothing, shoes, bedding, car set, etc.). Insulated bags are well known. The electric heater  100  can be inserted or otherwise disposed in a cavity/pocket  152  formed in or on a main body  154  of the product  150  as shown by arrow  152 . The electric heater  100  can be removed from and re-disposed in the cavity/pocket  152  as desired. The present solution is not limited to the arrangement. In some scenarios, the electric heater  100  is simply disposed on or in the main body  154 . 
     The electric heater is generally configured to emit thermal radiation to facilitate the heating of item(s) in proximity thereto. The item(s) can include, but is(are) not limited to, food item(s), fluid(s), body(ies) of living thing(s) (e.g., human(s) or animal(s)), electronic device(s), fabric item(s), and/or component(s) of vehicle(s) (e.g., a windshield, steering wheel and/or seat cushion). 
     As shown in  FIGS.  1 - 2   , the electric heater  100  comprises a heating pad  102  connected to an electronic coupler  104 . The heating pad  102  has a width  110 , a length  112 , and a thickness  202 . These dimensions  110 ,  112 ,  202  can be selected in accordance with any given application. In some scenarios, the thickness  202  is equal to or greater than 0.25 mm and less than or equal to 0.9 mm. The present solution is not limited in this regard. 
     Electronic circuit component(s) is(are) integrated in the heating pad  102 . The electronic circuit component(s) is(are) provided to facilitate the heating pad&#39;s production of thermal radiation and/or user control of the heating pad. The electronic circuit components can include, but are not limited to, sensor(s), batteries and/or flexible Input/Output (I/O) device(s)  116 . The input device(s) of  116  can include, but are not limited to, keypad(s), button(s), switch(es) and/or touch screen display(s). The output device(s) of  116  can be configured to provide tactile, visual and/or auditory feedback to the user. Accordingly, the output device(s) can include, but is(are) not limited to, Light Emitting Diodes (LEDs), Red Green Blue (RGB) light emitter(s), light bar(s), speaker(s), display screen(s), and/or vibration device(s). The feedback can indicate, for example, an on/off status of the electric heater  100 , a temperature setting of the electric heater  100 , a temperature of the heating pad  102 , a power supply level of charge, and/or a health or age of the heating pad  102 . The electronic circuit component(s) can include other devices as will be described in detail below. 
     In some scenarios, the output devices  116  can include light bar(s) and/or LEDs with different colors of light being emitted to respectively provide indications of different information. For example, a red light is emitted to indicate that the heating pad is at a high temperature. A yellow light is emitted to indicate that the heating pad is at a medium temperature. A green light is emitted to indicate that the heating pad is at a low temperature. The high, medium and low temperatures can be pre-set by a user of the heating pad or at the factory prior to distribution of the heating pad in commerce. The present solution is not limited to the particulars of this example. For example, in other scenarios, light can be continuously or periodically emitted to indicate a charge status of an internal battery. 
     The heating pad  102  can be at least partially (not shown) or fully (as shown in  FIG.  1   ) encompassed by the I/O device(s)  116 . Accordingly, the I/O device(s)  116  have multiple purposes such as (i) enabling user-software interactions with the heating pad, (ii) providing information, alerts and/or notifications to the user of the heating pad, (iii) protecting edges of the heating pad from fraying and/or damage, and/or (iv) providing the grip for holding the heating pad. With regard to purpose (iv), the I/O device(s)  116  can be formed of a rubber, plastic or other material which may or may not have a pattern  118 , (e.g., depressions, protrusions, etc.) formed thereon to facilitate comfortable handling of the heating pad. 
     During operation, the electronic circuit component(s) is(are) connected to external device(s) via cable  108  and/or connector  106 . Cables and connectors are well known. Any known or to be known cable and/or connector can be used here. The external device(s) can include, but is(are) not limited to, a controller  114  and/or a power source. The controller  114  can be removably coupled to cable  108  such that it can be exchanged with another controller in the event of damage thereto and/or interoperability thereof. 
     The heating pad  102  will now be described in more detail in relation to  FIGS.  3 - 9   . The heating pad  102  is designed to be flexible as shown in  FIG.  3    and washable as shown in 
       FIG.  8   . These features of the heating pad  102  allow the electric heater  100  to be used in various applications and/or with various types of items. 
     The heating pad  102  is generally configured to emit thermal radiation when power is supplied thereto from an external power source and/or an internal power source. It should be noted that the heating pad  102  is designed for use with a given voltage level (e.g., 5 V, 9 V, 12 V or 24 V). The temperature of the heating pad  102  is controlled by adjusting the current suppled thereto. The current level can be selected or otherwise adjusted automatically and/or manually. 
     In the automatic scenarios, the current level can be adjusted based on certain information. This information includes, but is not limited to, sensor data generated by sensors integrated with electric heater  100  and/or a device (e.g., a smart phone) external to the electric heater  100 . The sensor data can indicate an amount of pressure being applied to the heating pad  102 , a temperature of the heating pad  102 , a temperature of an external environment, a humidity of the external environment, a temperature of the item in proximity to the heating pad  102 , a geographic location of the heating pad  102 , and/or a height above sea level. 
     In the manual scenarios, the current level can be manually selected or adjusted by a user via controller  114  connected to the heating pad  102  via cable  108 . The controller  114  will be described in detail below. The controller  114  may comprise switch(es), depressible button(s), rotary knob(s), and/or wireless communication technology for interfacing with an external device (e.g., a smart phone) to allow for remote control of the current level. 
     When power is supplied to the heating pad  102 , its temperature increases by a given amount (e.g., to a temperature between 55° C. to 130° C.) in accordance with the amount of current flowing therethrough. Once the temperature reaches a desired temperature, the heating pad  102  is configured to maintain a constant temperature state. 
     As shown in  FIG.  4   , the heating pad  102  is formed of a plurality of layers  402 - 408  having a stacked arrangement. The layers  402 - 408  can be coupled to each other via adhesive(s), tape(s), stitch(es), chemical bond(s), weld(s), and/or lamination. The stacked layers comprise a heating fabric layer  402 , a circuit layer  404 , a nanotube-based film layer  406 , and a heating fabric layer  408 . The present solution is not limited to the number of layers shown in  FIG.  4   . Other layers can be included in the heating pad. These other layers can include, but are not limited to, a red copper film, a cloth- or fabric-based facing layer, a thermal insulation fabric layer, and a hot-melt mesh film. In one scenario in which these other layers are provided with the heating pad, the percentage of each material can be 1% red capper film, 25% cloth- or fabric-based facing material, 25% thermal insulation fabric, 24% hot-melt mesh film, and 25% layers  402 - 408 . The present solution is not limited to the particulars of this scenarios. 
     The heating fabric layer  402  is generally configured to produce thermal radiation when a voltage is supplied to the heating pad  102 . In this regard, the heating fabric layer  402  comprises an electrically conductive material that can be energized when power is supplied to the heating pad  102 . The electrically conductive material can include, but is not limited to, a graphene material (e.g., with an electrical conductivity at least 70% higher than copper), an oxford cloth (e.g., a woven fabric with a basketweave structure), and/or a heat storage and thermal insulation fabric. The graphene cloth can include, but is not limited to, polyester fibers and a graphene coating. The oxford cloth can include, but is not limited to, polyurethane. The The heat storage and thermal insulation fabric can include, but is not limited to, polyester fibers and a nano-silver film. The heating fabric layer  402  can have a width  410  selected in accordance with a given application (e.g., a width that is equal to or greater than 0.16 mm). 
     An illustrative graphene material that can be used as the graphene coating of the heating fabric layer  402  is shown in  FIG.  5   . The graphene material comprises a single layer of atoms  502  (e.g., carbon atoms) connected to each other via sp 2  hybridization to form a planar two-dimensional hexagonal honeycomb lattice structure  506 . The graphene material has relatively good optical, electrical and mechanical properties. In some scenarios, thermal radiation is emitted uniformly across the entire surface  504  of the graphene material as its temperature is increased to a given amount (e.g., 55° C.≤temperature≤130° C.). This uniform thermal radiation emission is shown in  FIG.  6   . Once the temperature reaches a desired temperature and the graphene materials is in thermal equilibrium, it can maintain a constant temperature state. 
     Based on the superconductivity and thermal properties of the graphene material, the temperature of the graphene material can increase to a given value in a relatively short amount of time (e.g., 60 to 180 seconds). As a result of the increased temperature, the graphene material releases far-infrared light waves that can penetrate item(s) that is(are) located in proximity to heating pad  102 . The item(s) can include, but is(are) not limited to, food item(s), fluid(s), body(ies) of living thing(s) (e.g., human(s) or animal(s)), electronic device(s), fabric item(s), and/or component(s) of vehicle(s) (e.g., a windshield, steering wheel and/or seat cushion). In food applications, the light waves penetrate the surface(s) of the food item(s) which facilitates the prevention of a decrease in the food item temperature(s) or facilitates an increase in the food item temperature(s). In human applications, the light waves penetrate the surface tissue of the individual&#39;s body which facilitates an acceleration of blood circulation, cell metabolism and other functions that are beneficial to the individual&#39;s health. 
     The nanotube-based film layer  406  is generally configured to provide physical support for layers  402 ,  404 ,  408  and facilitate heating of the heating pad  102 . In this regard, the nanotube-based film layer  406  comprises a film of intertwined nanotubes. The nanotubes can include, but are not limited to, carbon nanotubes. Carbon nanotube films are well known. The nanotube-based film layer  406  has a relatively high strength, electrical conductivity and thermal conductivity. 
     The heating fabric layer  408  is configured to provide a water-resistant layer, provide structural support to layers  402 - 406 , and facilitate heating of the heating pad  102 . The heating fabric layer  408  is also configured to allow thermal radiation to be emitted from the heating pad  102  on a side opposite to that of the heating fabric layer  402 . The heating fabric layer  408  can include, but is not limited to, a carbon fiber cloth, a graphite fiber cloth, a graphene cloth and/or a carbon/graphite fiber cloth. 
     The circuit layer  404  is generally configured to allow a voltage and current to be applied across a surface  416  of the heating fabric layer  416  and a surface  418  of the nanotube-based film layer  406 . In this regard, the circuit layer  404  comprises electronic components such as conductive material(s) (e.g., wires, a patterned film, a patterned foil and/or traces printed on layer  402  and/or  406 ) and/or electronic devices (e.g., flexible Integrated Circuits (ICs), sensor(s), etc.). The circuit layer  404  can be disposed on the heating fabric layer  402  and/or the nanotube-based film layer. The voltage and current may be applied uniformly or non-uniformly across surfaces  416 ,  418 . When the voltage/current are applied, the heating pad  102  emits thermal radiation  420  therefrom in one or more directions shown by arrows  422 ,  424 . 
     An insulation layer  430  may be disposed between the heating fabric layer  402  and the circuit layer  404 . The insulation layer  430  can include, but is not limited to, a thermally conductive silica gel. 
     A cover layer  432  may be disposed on the heating fabric layer  402 . The cover layer  432  can include, but is not limited to, a heat storage and insulation cloth, a hot melt omentum. The hot melt omentum can include, but is not limited to, a thermoplastic polyurethane. 
     The heating pad  102  can convert a relatively large amount of electric energy into heat and have a relatively high heat radiation efficiency. For example, in some scenarios as shown in  FIG.  7   , the heating pad  102  converts more than 90% of electric energy into heat and has a heat radiation efficiency of more than 70%. The present solution is not limited to the particulars of this example. A graph is provided in  FIG.  9    that shows a temperature rise curve for the heating pad  102  in a given scenario with a given voltage rating (e.g., 5 V). 
     The relative percentages of each layer  402 - 408 ,  430 ,  432  can be selected in accordance with a given application. For example, in some scenarios, the heating pad comprises 1% red copper film  404 , 25% cloth/fabric-based facing layer  432 , 25% thermal insulation fabric layer  430 , 24% hot melt mesh film  432 , and 25% layers  402 ,  406 ,  408 . In other scenarios, the heating pad comprises 31.7% layer  402 , 4.9% layer  404 , 31.7% layer  306  and 31.7% layer  408 . Accordingly, layer  402  can have a thickness of 0.08 mm. Layer  404  can have a thickness of 0.05 mm. Layer  406  can have a thickness of 0.08 mm. Layer  408  can have a thickness of 0.08 mm. The present solution is not limited to the particulars of these scenarios. 
     Referring now to  FIGS.  11 - 12   , there are provided illustrations showing the nanotube-based film layer  406  with the circuit layer  404  disposed thereon. The circuit layer  404  comprises a first conductive line portion  1130  and a second conductive line portion  1132 . Although two conductive line portions are shown in  FIG.  11   . The present solution is not limited in this regard. Any number of conductive line portions can be provided in accordance with a given application. 
     The first conductive line portion  1130  comprises two fingers  1134  which are connected to each other via connection line  1138 . The second conductive line portion  1132  comprises two fingers  1136  that are connected to each other via connection line  1140 . The fingers  1134  and  1136  are interdigitated meaning that at least one finger  1134  resides between fingers  1136  and at least one finger  1136  resides between fingers  1134 . During operation, power is provided to both conductive line portions simultaneously or concurrently such that the heat radiation emitted from the heating pad  102  is uniform across its surfaces. The present solution is not limited in this regard. The first and second conductive line portions can be designed such that heat radiation emission is not uniform across the heating pad&#39;s surfaces. For example, the first and second conductive line portions can have a different number of fingers and/or serpentine patterns. 
     Although only two fingers are shown in  FIG.  11    per conductive line portion, the present solution is not so limited. Any number of fingers can be provided in accordance with a given application. For example, in another architecture shown in  FIG.  13   , each conductive line portion comprises three fingers. The heating pad of  FIG.  13    has an overall thickness that is greater than an overall thickness of the heating pad of  FIGS.  11 - 12   . 
     The conductive line portions  1130 ,  1132  are connected to the cable  108  via wires  1106 ,  1110  and electrodes  1108 ,  1112 . In some scenarios, at least the wire-electrode connections are enclosed or otherwise encompassed by an environmental seal component  1300  as shown in  FIG.  13   . The environment seal component  1300  is provided to ensure or minimize any damage to the circuit components due to fluid(s), debris, deformation of the heating pad and/or extreme temperature change(s) beyond that which the electronic device is intended to operate in. 
     The cable  108  is connected to a controller  114 . The controller  114  will be described in detail below. Still, it should be noted here that the controller  114  is generally configured to facilitate the turning On/Off of the electric heater  100  whereby a voltage is applied to the heating pad  102  and/or the adjustment of an amount of current that is supplied to the circuit layer  404  via cable  108  whereby the overall temperature of the heating pad  102  is increased/decreased. Accordingly, the controller  114  may also coupled to an internal power source via wires  1114  and/or an external power source via cable  108 . The internal power source can include, but is not limited to, flexible batteries (e.g., graphene batteries), flexible energy harvesting circuit (e.g., flexible piezoelectric energy harvester), and/or capacitor(s). The energy harvesting circuit can be configured to harvest energy from light, movement (e.g., vibration), and/or Radio Frequency (RF) signals. 
     The circuit layer  404  also comprises electronic device(s)  1116 . The electronic device(s)  1116  can include, but is(are) not limited to, Integrated Circuit(s) (ICs), processor(s), data store(s), wireless communication devices (e.g., flexible wireless transceiver(s)), temperature sensor(s) (e.g., thermistor(s)), moisture sensor(s), location sensor(s), proximity sensor(s), pressure sensor(s), sound sensor(s), camera(s) and/or power supply circuits. The temperature sensor(s) can detect and measure the temperature of the heating pad  102 , the temperature of a surrounding environment, and/or a temperature of an item in proximity thereto. The moisture sensor(s) can detect and measure the amount of moisture in the heating pad  102  and/or the humidity of a surrounding environment. The location sensor(s) can detect a geographic location of the heating pad  102  and/or a distance of the heating pad  102  from sea level. The pressure sensor(s) can detect and/or measure an amount of pressure being applied to the heating pad by an external object. The pressure measurement can be used to facilitate control of the electric heater  100 . The proximity sensor(s) can detect when an item is proximate thereto. The sound sensor(s) can detect the presence of sound and/or measure an amount of sound or variations in sound pressure. The sound sensor can include, but is not limited to, a diaphragm microphone. The camera(s) can capture image(s) of a surrounding environment and/or an item in proximity to the electric heater. The sensor data can be stored in data store(s) internal to and/or external to the heating pad  102 . The electronic device(s)  1116  is(are) coupled to the controller  1118  via wires  1114  of cable  108 . 
     The present solution is not limited to the architecture shown in  FIG.  11   . The sensors can have different sizes, shapes and/or locations than that shown in  FIG.  11   . For example, as shown in  FIG.  13 B , a relatively large pressure sensor  1302  is provided in addition to other electronic devices  1304 . The pressure sensor  1302  can disposed on the heating fabric layer  402  or the nanotube-based film layer  406 . The pressure sensor  1302  can have a length (e.g., 250 mm), a width (e.g., 15 mm) and a thickness (e.g., 0.2 mm) selected in accordance with a particular application. The pressure sensor  1302  can have a working temperature of, for example, −40° C.+100° C. The present solution is not limited to the particulars of  FIG.  13 B . 
     The sensor data can be used to facilitate the control of the electric heater  100 . For example, the electric heater  100  can be automatically turned on when the heating pad detects that a particular type of object is in proximity thereto. This detection can be made using data generated by the proximity sensor(s), pressure sensor(s), sound sensor(s), camera(s) and/or location sensor(s). In this regard, it should be noted that a first food item of a first type would apply less pressure to the heating pad than a second food item of a second type, e.g., when the first food item weighs less than the second food item. Thus, pressure measurement(s) can be compared to entries in a Look Up Table (LUT) and/or threshold hold values that are pre-defined by certain types of items. An item is considered to be of a given type associated with an LUT entry in which the pressure measurement(s) exist. The present solution is not limited to the particulars of this example. 
     In some scenarios, the amount of current supplied to the heating pad  102  is automatically adjusted by controller  1118  based on information received from the electronic device(s)  1116  and/or other information received from an external device  1150 . The external device  1150  can include, but is not limited to, a mobile phone, a smart phone, a personal digital assistant, a personal computer, a desktop computer, a laptop, a tablet, a remote controller, a cloud based system and/or a network node. For example, the current is adjusted when a humidity of a surrounding environment exceeds a threshold value, an amount of moisture in the heating pad exceeds a threshold level, and/or the distance of the heating pad above sea level exceeds a threshold value. Alternatively or additionally, the current may be selected so that the temperature of the heating pad increases to a desired level in a given amount of time dependent on conditions of a surrounding environment (e.g., temperature and/or humidity). An LUT can be used to facilitate the current selection. The present solution is not limited to the particulars of this example. 
     If batteries are integrated or otherwise disposed in the heating pad  102 , a battery charger  1152  can be provided to re-charge the batteries. The battery charger  1152  can include, but is not limited to, an inductive battery charger, a wireless battery charger and/or a wired battery charger designed to be coupled/decoupled from the controller  114 . The battery charger  1152  may be configured to be used to charge the internal or external batteries of the heating pad relatively quickly. The battery charger  1152  may or may not be compatible for use in charging batteries of other electronic device (i.e., devices other than the electric heater and/or external power source). The battery charger  1152  may have output devices for indicating a battery charge states (e.g., a fully charged status, a partially charged status or a low charge status). The output devices can include, but are not limited to, LEDs, display(s), and/or speaker(s). 
     Referring now to  FIG.  14   , there is provided a top perspective view of controller  114 . Controller  114  is generally configured to facilitate control of the electric heater  100 . In this regard, controller  114  comprises a housing  1402  in which a circuit (not visible in  FIG.  14   ) is disposed. The circuit is generally configured to facilitate operational mode transitions of the electronic heater  100 . The operational modes include, but are not limited to, an On/Off mode, a low heat mode, a medium heat mode, a high heat mode, and/or a battery charging mode. Accordingly, the circuit can include, but is not limited to, I/O devices (e.g., switch(es), button(s), knob(s) and/or touch screen) and/or a computing device (e.g., computing device  1600  of  FIG.  16   ). The housing  1402  may include two parts coupled to each other so as to provide an environmental seal to protect the internal circuit from damage due to, for example, liquids and/or debris. The housing can be made of any suitable material such as plastic. 
     Marking(s)  1406  may be disposed on, printed on or formed in the housing  1402 . The marking(s)  1406  can indicate to a user an operational state of the electric heater (e.g., an on state, an off state, a battery charging state, etc.) and/or the setting for a heat level parameter of the heating pad  102 . For example, there may be five settings for the heat/current level parameter with one being the lowest setting and five being the highest setting. The present solution is not limited to the particulars of this example. 
     Referring now to  FIG.  15   , there is provided a perspective view of an illustrative power source  1500  that can be used with the electric heater  100 . The power source can include, but is not limited to, graphene batteries. The power source  1500  may be configured with different capacities (e.g., 5000 mAh, 10000 mAh, 15000 mAh and/or 20000 mAh) and/or different voltage outputs (e.g., 5 V, 9 V, 12 V, 20 V and/or 24 V). In some scenarios, the output voltage has a default setting of 12 V with 5 A current. The present solution is not limited in this regard. One or more types of output ports can be provided with power source  1500 . For example, the power source has a Type C output port  1502  and a Universal Serial Bus (USB) port  1504 . The present solution is not limited to the particulars of this example. The power source  1500  may be configured to automatically stop the supply of power to the electric heater  100  when the electric heater is not in use and/or an object of a given type is not in proximity to the electric heater. The power supplied from the power source  1500  to the electric heater is uniform and independent of the heat generating mechanism in the heating pad. 
     In the insulated bag scenarios, the power source  1500  may be also stored in the insulated bag  150  or can be external to the insulate bag. The electric heater  100  can be connected to the power source  1500  prior to or subsequent to being inserted into cavity/pocket  152  of the insulated bag  150  or the electric heater can just be placed in the insulated bag. A separate pocket  154  may optionally be provided in the cavity/pocket for receiving and retaining the power source  1500  in a given position inside the insulated bag relative to the heating pad  102 . Pocket  254  can ensure that power is continuously supplied from the power source  1500  to the electric heater  100  throughout use and/or transport of the insulated bag. 
     Referring now to  FIG.  16   , there is shown a hardware block diagram comprising an illustrative computing device  1600 . Controller  114  of  FIG.  1   , electronic device(s)  1116  of  FIG.  11   , electronic device  1150  of  FIG.  1   , battery charger  1152  of  FIG.  11    and/or power supply  1500  of  FIG.  15    can be the same as or substantially similar to computing device  1600 . As such, the discussion of computing device  1600  is sufficient for understanding controller  114  of  FIG.  1   , electronic device(s)  1116  of  FIG.  11   , electronic device  1150  of  FIG.  1   , battery charger  1152  of  FIG.  11    and/or power supply  1500  of  FIG.  15   . 
     Computing device  1600  may include more or less components than those shown in  FIG.  16   . However, the components shown are sufficient to disclose an illustrative solution implementing the present solution. The hardware architecture of  FIG.  16    represents one implementation of a representative computing device configured to enable heating of item(s) as described herein. As such, the computing device  1600  of  FIG.  16    implements at least a portion of the method(s) described herein. 
     Some or all the components of the computing device  1600  can be implemented as hardware, software and/or a combination of hardware and software. The hardware includes, but is not limited to, one or more electronic circuits. The electronic circuits can include, but are not limited to, passive components (e.g., resistors and capacitors) and/or active components (e.g., amplifiers and/or microprocessors). The passive and/or active components can be adapted to, arranged to and/or programmed to perform one or more of the methodologies, procedures, or functions described herein. 
     As shown in  FIG.  16   , the computing device  1600  comprises a user interface  1602 , a CPU  1606 , a system bus  1610 , a memory  1622  connected to and accessible by other portions of computing device  1600  through system bus  1610 , and hardware entities  1614  connected to system bus  1610 . The user interface can include input devices (e.g., a keypad  1650 ) and output devices (e.g., a speaker  1652 , a display  1654 , and/or light emitting diodes  1656 ), which facilitate user-software interactions for controlling operations of the computing device  1600 . 
     At least some of the hardware entities  1614  perform actions involving access to and use of memory  1622 , which can be a RAM, a disk driver, network device, cloud-based device, and/or a CD-ROM. Hardware entities  1614  can include a disk drive unit  1616  comprising a computer-readable storage medium  1618  on which is stored one or more sets of instructions  1620  (e.g., software code) configured to implement one or more of the methodologies, procedures, or functions described herein. The instructions  1620  can also reside, completely or at least partially, within the memory  1622  and/or within the CPU  1606  during execution thereof by the computing device  1600 . The memory  1622  and the CPU  1606  also can constitute machine-readable media. The term “machine-readable media”, as used here, refers to a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions  1620 . The term “machine-readable media”, as used here, also refers to any medium that is capable of storing, encoding or carrying a set of instructions  1620  for execution by the computing device  1600  and that cause the computing device  1600  to perform any one or more of the methodologies of the present disclosure. 
     In some scenarios, the hardware entities  1614  include an electronic circuit (e.g., a processor) programmed for facilitating the heating of item(s). In this regard, it should be understood that the electronic circuit can access and run application(s)  1624  and/or a machine learning application(s)  1626  installed on the computing device  1600 . 
     The application(s)  1624  may be configured to facilitate control and/or operation of an electric heater (e.g., electric heater  100  of  FIG.  1   ). Accordingly, the application(s)  1624  can be used to check an operational mode of the electric heater, modify or otherwise transition an operational mode of the electric heater, check parameter settings for the electric heater (e.g., a temperature setting, a current setting and/or a voltage rating), modify parameter settings for the electric heater and/or power source, check battery charge levels for the electric heater and/or power source, check an energy harvesting status for a heating pad, check if any faults have been detected during use of the electric heater, define parameters for a customized heat cycle (e.g., a time of day for automatic turning on of the electric heater (e.g., 8 AM EST), a temperature level (e.g., 100° F.), a duration (e.g., 20 minutes), a time of day for automatic turning off of the electric heater (e.g., 8:20 AM EST), and/or a recurrence parameter settings (e.g., daily, every other day, every Thursday, every N weeks, etc.), check how many times the electric heater has been used during a given period of time (e.g., a day, week or month), check a health of the heating pad (E.g. strong, good, average or poor), initiate pairing or linking of the computing device with an electric heater, and/or cause wireless communication between the computing device paired or linked electric heater. 
     The application(s)  1624  can also facilitate the remote control of operational settings for a group of electric heaters such that they all operate in accordance with policies of a business entity (e.g., a restaurant or a chain of restaurants) or for an individual (e.g., heat pad on different body part locations like legs, chest, etc.). In this way, operational setting of two or more electric heaters can be set via common user-software interactions with the computing device  1600 . For example, a user can select a single temperature value via a widget displayed on the computing device which causes the temperature setting to be changed on a plurality of electric heaters. The present solution is not limited in this regard. 
     In some scenarios, operational parameters for the electric heater  100  are pre-defined or customized for use with certain types of items. The sets of pre-defined/customized operational parameters can be stored in a datastore of the computing device and/or selected via a user interaction with application(s)  1624 . For example, a user accesses a drop-down menu of a Graphical User Interface (GUI) presented on display  1654  and selects an item type from a plurality of different item types listed in the drop-down menu. The item type selection causes the electric heater to be controlled in accordance with pre-defined/customized operational parameters associated therewith. 
     The machine learning application(s)  1626  may implement(s) Artificial Intelligence (AI) that provides the computing device  1600  with the ability to automatically learn and improve data analytics from experience without being explicitly programmed. The machine learning application(s) employ(s) one or more machine learning algorithms that learn various information from accessed data (e.g., via pattern recognition and prediction making). Machine learning algorithms are well known in the art. For example, in some scenarios, the machine learning application  1626  employs a supervised learning algorithm, an unsupervised learning algorithm, and/or a semi-supervised algorithm. The machine learning algorithm(s) is(are) used to model temperature decisions based on data analysis (e.g., captured sensor information and other information). The modelled temperature decisions are represented in a machine learning model. 
     The machine learning model can be used to determine optimal temperature setting(s) for the electric heater based on various information. This information can include, user input information (e.g., user identifier, user preferences, medical information, physical condition information, etc.), sensor data (e.g., location of electric heater, temperature of heating pad, amount of pressure being applied to heating pad, and/or amount of moisture in fabric of heating pad, etc.), environmental data (e.g., temperature and/or humidity of surrounding environment, etc.), time of day, time of year, and/or type of item being heated (e.g., food, fluid/liquid, clothing, gloves, shoes, hat, blanket, car seat, etc.). In this way, operation of the electric heater can be customized and/or optimized for environmental conditions, item types, users, user preferences and/or user medical conditions. 
     Referring now to  FIG.  17   , there is provided a flow diagram of an illustrative method  1700  for making a heating fabric layer  402 . As noted above, the heating fabric layer  402  can include a graphene cloth or fabric. The graphene cloth or fabric used herein is a novel cloth/fabric that is absent of various drawbacks of conventional graphene sheets. Conventional graphene sheets have poor heating uniformity, high material hardness, easy internal fracturing, multiple impurities, poor conductivity, poor stability, short service lives and/or high resistance (which results in excessive power consumption). In contrast, the present graphene cloth/fabric of the present solution has a relatively higher electrothermal conversion rate, electrical conductivity, thermal conductivity, stability, thermal uniformity, flexibility and longevity. 
     Method  1700  begins with  1702  and continues with  1704  where a graphene slurry is obtained. The graphene slurry is made of graphene powder, curing agent, auxiliary agent and other components. The following table lists the raw materials for the graphene slurry. 
     
       
         
           
               
               
               
             
               
                   
               
               
                 No. 
                 Material Name 
                 Purity, Concentration 
               
               
                   
               
             
            
               
                 1 
                 Graphene 
                 Analytically pure, 98% 
               
               
                 2 
                 Polyurethane resin 
                 Number average molecular 
               
               
                   
                   
                 weight 2200/3500 
               
               
                 3 
                 N,N-Dimethylformamide 
                 Analytically pure, 99.5% 
               
               
                 4 
                 Additives A 
                 Analytically pure, 99% 
               
               
                 5 
                 Additives B 
                 Type 201 
               
               
                 6 
                 Additives C 
                 Analytically pure, 97% 
               
               
                 7 
                 Additives D 
                 Analytically pure, 99% 
               
               
                 8 
                 Additives E 
                 52% 
               
               
                   
               
            
           
         
       
     
     The graphene slurry can be prepared by, for example: accurately weighing 45 g of Thermoplastic Polyurethane (TPU) resin with a number average molecular weight of 22000; dissolving the TPU in 150 g of Dimethylformamide (DMF) at a dissolution temperature of 80° C.; waiting until the dissolution is completely reduced to room temperature; adding 55 g of Auxiliary A to the dissolution; stirring the mixture evenly to produce a first resin solution; accurately weigh 35 g of TPU resin with a number average molecular weight of 35000; dissolving the TPU in 150 g of DMF at a dissolution temperature of 80° C.; waiting until the dissolution is completely reduced to room temperature; adding 65 g of Auxiliary A to the dissolution; stirring the mixture evenly to produce a second resin solution. The first and second resin solutions are mixed together and stirred uniformly at a mass ratio of 1:1 to prepare a graphene solvent. Graphene slurries with different concentration gradients can be prepared in accordance with this process. The mass concentrations can include, but are not limited to, 3.5%, 4.5%, 5.5%, 6.5%, 7.5%, 8.5% and/or 9.5%. The total mass fraction of the four additives can also be varied. 
     Next in  1706 , a glass sheet is coated with the graphene slurry. The coated glass sheet is then placed in an oven heated to a given temperature (e.g., 120° C.), as shown by  1708 . In  1710 , the coated glass sheet remains in the oven for a given period of time (e.g., 2 hours) so that the graphene slurry dries at a constant temperature. The dried graphene slurry forms a 2D hexagonal honeycomb graphene structure. The glass sheet and 2D hexagonal honeycomb graphene structure are then removed from the oven in  1712 . The same are allowed to cool in  1714  at room temperature. The cooled 2D hexagonal honeycomb graphene structure is referred to as a graphene cloth or fabric. 
     In  1716 , the graphene cloth or fabric is then peeled off of the glass sheet such that the 2D hexagonal honeycomb structure is retained. The peeling process ensures that the overall performance of electrothermal conversion rate, electrical conductivity, thermal conductivity, stability, thermal uniformity, flexibility and longevity are improved as compared to those of conventional graphene sheets. 
     Referring now to  FIG.  18   , there is provided a flow diagram of an illustrative method  1800  for making a heating pad (e.g., heating pad  102  of  FIG.  1   ). Method  1800  begins with  1802  and continues with  1804  where a graphene cloth/fabric is obtained. The graphene cloth/fabric may be produced in accordance with method  1700  discussed above. A base fabric is laid on the graphene fabric/cloth in  1806 . The base fabric can include, but is not limited to, a polyester cloth. An adhesive may optionally be disposed on a surface of the base fabric as shown by  1808 . The adhesive may include, but is not limited to, a thermally conductive silicon adhesive. Next in  1810 , a hot press is used to apply heat and pressure to the assembled stack comprising the graphene cloth/fabric and base fabric. 
     Thereafter in  1812 , a circuit layer is disposed on the graphene cloth/fabric. The circuit layer can include a patterned conductive film and/or electronic devices (e.g., sensors, etc.). In  1814 , an adhesive may optionally be disposed on a surface of the circuit layer. A cord/cable (e.g., cable  108  of  FIG.  1   ) and/or signal lines are connected in  1816  to electrodes (e.g., electrodes  1108 ,  1112  of  FIG.  11   ) of the circuit layer. The connections and/or operations of the circuit are then checked or tested in  1818 . For example, a wireless communication capability is tested for proper operation. If the circuit connections and operations are satisfactory, then a low temperature hot melt film with a release paper is disposed on the graphene cloth/fabric and circuit layer in  1820 . Next in  1822 , heat and pressure are then applied to the assembly stack as shown by  1820 . 
     In  1824 , a release paper on the surface of the hot melt film is torn off. A heat storage and insulation fabric and/or graphene cloth is set on a surface of the low temperature hot melt film. Heat and pressure are applied to the assembled stack in  1826 . The heat storage/heat preservation fabric is integrated with the graphene flexible heating cloth, the circuit layer and electric components. 
     The quality of the finished product is inspected in  1828  and re-inspected in  1830 . The inspections of  1828  and  1830  can involve checking whether an appearance is defective, whether the detection circuit is normal, whether the detection sensor signal is normal, whether the working current and resistance are normal, whether the wireless communication between an external device (e.g., a smart phone) and the controller is normal, and/or whether the heating temperature is normal. Subsequently,  1832  is performed where method  1800  ends or other operations are performed. 
     The above described processes  1700 ,  1800  have been used to produce heating pads comprising graphene cloths/fabrics with different thicknesses. The following Examples are provided that are useful for understanding similarities and differences in the electrical properties of graphene flexible heating cloths having different thicknesses. 
     EXAMPLE 1 
     In this example, a relatively thin graphene heating pad  1900  is created. The layer structure for this heating pad  1900  is shown in  FIG.  19   . The layers include a heat storage and insulation cloth  1902 , a hot melt omentum  1904 , a circuit layer  1906 , a graphene flexible heating cloth/membrane  1908 , and a base fabric (e.g., a polyester cloth)  1910 . The present solution is not limited to the particulars of this example. 
     EXAMPLE 2 
     In this example, a relatively thick graphene heating pad  2000  is created. The layer structure for this heating pad  2000  is shown in  FIG.  20   . The layers include a graphene cloth  2002 , a hot melt omentum  2004 , a heat storage and insulation cloth  2006 , a circuit layer  2008 , a graphene flexible heating cloth  2010 , a base fabric  2012 , and a hot melt interlining  2014 . 
     Illustrative temperatures and pressures used during process  1800  for the hot melt and low temperature melt meshes are: high temperature hot melt mesh omentum—hot pressing temperature 145° C. to 160° C. and pressure 2 KG; low temperature hot melt omentum—hot pressing temperature 90° C. and pressure 2 KG. After the heating pad is integrated by hot pressing, as long as the temperature for the graphene flexible heating pad does not exceed 120 ° C., the performance of the hot melt film will not be affected. The present solution is not limited to the particulars of this example. 
     EXAMPLE 3 
     In this example, a relatively thin graphene heating pad  2100  is created. The layer structure for this heating pad  2100  is shown in  FIG.  21   . The layers include a heat storage insulation fabric  2102 , a hot melt omentum  2104 , a circuit layer  1206 , a graphene flexible heating cloth/membrane  2110 , and a base fabric (e.g., a polyester cloth)  2112 . The heating pad  2100  comprise 31.7% heat storage insulation fabric  2102 , 3.9% hot melt omentum  2104 , 1% circuit layer  1206  (e.g., a red copper film), 31.7% graphene flexible heating cloth/membrane  2110 , and 31.7% base fabric  2112 . The present solution is not limited to the particulars of this example. 
     EXAMPLE 4 
     In this example, a heating pad is created using a graphene flexible heating cloth that has a thickness (e.g., thickness  410  of  FIG.  4   ) of 8 mm, a width of 20 cm, a length of 30 cm, an area of 600 cm 2 , and a surface resistance of 2.65 Ohms. The ambient temperature is 17° C. and the environmental humidity is &gt;85%. 
     
       
         
           
               
            
               
                   
               
               
                 Temperature and power density 
               
            
           
           
               
               
               
            
               
                 Heating Temp. (° C.) 
                 Power (W/cm 2 ) 
                 Power (KW/m 2 ) 
               
               
                   
               
               
                 30 
                 0.0912 
                 91.20 
               
               
                 40 
                 0.0916 
                 91.60 
               
               
                 50 
                 0.0920 
                 92.00 
               
               
                 60 
                 0.0924 
                 92.40 
               
               
                 70 
                 0.0926 
                 92.60 
               
               
                 75 
                 0.0928 
                 92.80 
               
               
                 80 
                 0.0932 
                 93.20 
               
               
                 85 
                 0.0936 
                 93.60 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 Electrical Properties 
               
            
           
           
               
               
               
               
            
               
                 Heating Temp (° C.) 
                 Power (W) 
                 Voltage (V) 
                 Current (A) 
               
               
                   
               
               
                 30 
                 54.72 
                 12 
                 4.56 
               
               
                 40 
                 54.96 
                 12 
                 4.58 
               
               
                 50 
                 55.20 
                 12 
                 4.60 
               
               
                 60 
                 55.44 
                 12 
                 4.62 
               
               
                 70 
                 55.56 
                 12 
                 4.63 
               
               
                 75 
                 55.68 
                 12 
                 4.64 
               
               
                 80 
                 55.92 
                 12 
                 4.66 
               
               
                 85 
                 56.16 
                 12 
                 4.68 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 Heating temperature rise time 
               
            
           
           
               
               
               
            
               
                   
                 Heating Time 
                 Temp (° C.) 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                 30 
                 seconds 
                 35 
               
               
                 1 
                 minute 
                 40 
               
               
                 2 
                 minutes 
                 50 
               
               
                 4 
                 minutes 
                 60 
               
               
                 6 
                 minutes 
                 65 
               
               
                 8 
                 minutes 
                 70 
               
               
                 10 
                 minutes 
                 75 
               
               
                 13 
                 minutes 
                 80 
               
               
                 15 
                 minutes 
                 85 
               
               
                   
               
            
           
         
       
     
     The present solution is not limited to the particulars of this example. 
     EXAMPLE 5 
     In this example, a heating pad is created using a graphene flexible heating cloth that has a thickness (e.g., thickness  410  of  FIG.  4   ) of 8 mm, a width of 20 cm, a length of 30 cm, an area of 600 cm 2 , and a surface resistance of 3.11 Ohms. The ambient temperature is 17° C. and the environmental humidity is &gt;85%. 
     
       
         
           
               
            
               
                   
               
               
                 Temperature and power density 
               
            
           
           
               
               
               
            
               
                 Heating Temp. (° C.) 
                 Power (W/cm 2 ) 
                 Power (KW/m 2 ) 
               
               
                   
               
               
                 30 
                 0.0740 
                 74.00 
               
               
                 40 
                 0.0742 
                 74.20 
               
               
                 50 
                 0.0744 
                 74.40 
               
               
                 60 
                 0.0746 
                 74.60 
               
               
                 70 
                 0.0755 
                 75.50 
               
               
                 75 
                 0.0760 
                 76.00 
               
               
                 80 
                 0.0764 
                 76.40 
               
               
                 85 
                 0.0771 
                 77.10 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 Electrical Properties 
               
            
           
           
               
               
               
               
            
               
                 Heating Temp (° C.) 
                 Power (W) 
                 Voltage (V) 
                 Current (A) 
               
               
                   
               
               
                 30 
                 44.40 
                 12 
                 3.70 
               
               
                 40 
                 44.52 
                 12 
                 3.71 
               
               
                 50 
                 44.68 
                 12 
                 3.72 
               
               
                 60 
                 44.80 
                 12 
                 3.73 
               
               
                 70 
                 45.30 
                 12 
                 3.77 
               
               
                 75 
                 45.60 
                 12 
                 3.80 
               
               
                 80 
                 45.85 
                 12 
                 3.82 
               
               
                 85 
                 46.30 
                 12 
                 3.85 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 Heating temperature rise time 
               
            
           
           
               
               
               
            
               
                   
                 Heating Time 
                 Temp (° C.) 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                 30 
                 seconds 
                 38 
               
               
                 1 
                 minute 
                 40 
               
               
                 2 
                 minutes 
                 50 
               
               
                 3 
                 minutes 
                 55 
               
               
                 4 
                 minutes 
                 60 
               
               
                 5 
                 minutes 
                 65 
               
               
                 7 
                 minutes 
                 70 
               
               
                 10 
                 minutes 
                 75 
               
               
                 12 
                 minutes 
                 80 
               
               
                 15 
                 minutes 
                 85 
               
               
                   
               
            
           
         
       
     
     The present solution is not limited to the particulars of this example. 
     EXAMPLE 6 
     In this example, a heating pad is created using a graphene flexible heating cloth that has a thickness (e.g., thickness  410  of  FIG.  4   ) of 0.26 mm, a width of 20 cm, a length of 30 cm, an area of 600 cm 2 , and a surface resistance of 2.65 Ohms. The ambient temperature is 17° C. and the environmental humidity is &gt;85%. 
     
       
         
           
               
            
               
                   
               
               
                 Temperature and power density 
               
            
           
           
               
               
               
            
               
                 Heating Temp. (° C.) 
                 Power (W/cm 2 ) 
                 Power (KW/m 2 ) 
               
               
                   
               
               
                 30 
                 0.0912 
                 91.20 
               
               
                 40 
                 0.0916 
                 91.60 
               
               
                 50 
                 0.0920 
                 92.00 
               
               
                 60 
                 0.0924 
                 92.40 
               
               
                 70 
                 0.0926 
                 92.60 
               
               
                 75 
                 0.0928 
                 92.80 
               
               
                 80 
                 0.0932 
                 93.20 
               
               
                 85 
                 0.0936 
                 93.60 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 Electrical Properties 
               
            
           
           
               
               
               
               
            
               
                 Heating Temp (° C.) 
                 Power (W) 
                 Voltage (V) 
                 Current (A) 
               
               
                   
               
               
                 30 
                 54.72 
                 12 
                 4.56 
               
               
                 40 
                 54.96 
                 12 
                 4.58 
               
               
                 50 
                 55.20 
                 12 
                 4.60 
               
               
                 60 
                 55.44 
                 12 
                 4.62 
               
               
                 70 
                 55.56 
                 12 
                 4.63 
               
               
                 75 
                 55.68 
                 12 
                 4.64 
               
               
                 80 
                 55.92 
                 12 
                 4.66 
               
               
                 85 
                 56.16 
                 12 
                 4.68 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 Heating temperature rise time 
               
            
           
           
               
               
               
            
               
                   
                 Heating Time 
                 Temp (° C.) 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                 30 
                 seconds 
                 35 
               
               
                 1 
                 minute 
                 40 
               
               
                 3 
                 minutes 
                 50 
               
               
                 6 
                 minutes 
                 60 
               
               
                 8 
                 minutes 
                 65 
               
               
                 10 
                 minutes 
                 70 
               
               
                 13 
                 minutes 
                 75 
               
               
                 15 
                 minutes 
                 80 
               
               
                 20 
                 minutes 
                 85 
               
               
                   
               
            
           
         
       
     
     The present solution is not limited to the particulars of this example. 
     The described features, advantages and characteristics disclosed herein may be combined in any suitable manner. One skilled in the relevant art will recognize, in light of the description herein, that the disclosed systems and/or methods can be practiced without one or more of the specific features. In other instances, additional features and advantages may be recognized in certain scenarios that may not be present in all instances. 
     Although the systems and methods have been illustrated and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In addition, while a particular feature may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Thus, the breadth and scope of the disclosure herein should not be limited by any of the above descriptions. Rather, the scope of the invention should be defined in accordance with the following claims and their equivalents.