WO2021025663A1

WO2021025663A1 - Thermally conductive layer

Info

Publication number: WO2021025663A1
Application number: PCT/US2019/044797
Authority: WO
Inventors: Charles J. Cauchy
Original assignee: Gentherm Incorporated
Priority date: 2019-08-02
Filing date: 2019-08-02
Publication date: 2021-02-11
Also published as: WO2021025663A8

Abstract

In many heated and cooled surface applications, such as in automotive seating, a layer of compressible comfort material, usually foam, covers the hard seat frame materials along with hiding all the components underneath. The comfort material generally acts as a thermal insulator, ruining the efficiency of the heating or cooling to the seat occupant. An improvement is made for transferring significantly greater amounts of heat and/or coolness through the foam layer to the occupant. A woven thermally conductive layer for more evenly and efficiently distributing heat and or cooling across a surface, includes a thermal engine capable of generating heat and coolness in thermal communication with a compressible comfort material having a plurality of flexible sheeted thermally conductive strips interwoven through the compressible comfort material. The flexible sheeted thermally conductive strips are thermally coupled to the source of thermal modulation and distributed across any desired portion of the surface.

Description

THERMALLY CONDUCTIVE AYER

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation in Part (CIP) of International PCT Application No.: PCT/US 18/23443, filed on March 21, 2018, which is a Continuation in Part (CIP) of International PCT Application No.: PCT/US2015/060955, filed November 16, 2015 and claims priority with the benefit under 35 U.S.C. 119(e) of US Provisional Application No. 62/080,072 filed November 14, 2014, International PCT Application No.: PCT/US2015/060955, filed November 16, 2015, International PCT Application No.: PCT/US 18/23443, filed on March 21, 2018, US Provisional Patent Application Serial No.: 62/353,987, filed June 23, 2016 and US Provisional Patent Application Serial No.: 62/473,966, filed March 20, 2017 and US Provisional Patent Application Serial No.: 62/563,702, filed September 27, 2017 and US National Stage Utility Patent Application No.: 15/526,954, filed on May 5, 2017 .

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not Applicable

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC OR AS A TEXT FILE VIA THE OFFICE ELECTRONIC FILING SYSTEM fEFS WEB)

Not Applicable

STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR

OR A JOINT INVENTOR

Not Applicable BACKGROUND OF THU INVENTION

1. Field of the Invention

The present invention relates to a thermally conductive layer incorporated into a top layer of comfort materials, such as foam, felted mats and the like for use in conjunction with heated and cooled assemblies in seats for, among other applications, automotive, furniture, garment, medical and recreational applications, including OEM and aftermarket heaters/coolers, methods of manufacturing the same, and methods of using the same. More particularly, the invention relates to thermally conductive heat transfer systems in foam for top foam layers in heating and cooling automotive seats, office furniture seats of all types, medical therapy pads, food warmers, recreational vehicle seats, garments and other articles of clothing, as well as any desired heating and/or cooling application.

The subject matter of co-pending US patent application no. 15/526,954 is incorporated in its entirety herein by reference.

2. Description of the Prior Art

In order to provide comfort in a seating application, conventional top foam layers are common for covering conventional seats. Some prior art seats include heating systems for many seat applications, including vehicle seats of all types. Conventional heated seats have also been covered with a top foam layer covering for comfort, whether they included inefficient electric resistance heating mechanisms or any other type of heating mechanism.

Practitioners of those conventional heating and cooling system inventions have become aware of certain issues which are presented by those prior art inventions. One particular problem that has plagued car manufacturers and consumers has been that those systems utilized a top foam layer that unfortunately acts as a thermal insulator, thereby preventing much, if not all, of the heat generated by the heating system to be felt by the seat occupant. Consequently, a great deal of energy is used due to the inefficiency associated with heat transfer overcoming the insulation effect of the top layer of foam covering the seat. Further, there are other complexities which give rise to interior space concerns along with these energy consumption issues.

As anyone knows who has recently purchased a vehicle, heated seats are very popular. Although the present invention is applicable to any heated surface, including seats which may be used in a multitude of applications automotive, furniture, medical or otherwise, this patent application will be focus on the automobile, as that represents the largest sales volume of heated/cooled seats which are purchased by the public. Clearly, mechanisms for heating and cooling seats may be useful for many other applications, and some are more fully described hereinbelow. Although most of the following description will be discussed in the context of automotive seating, it is clear that the technology of the present invention is readily applicable to all other applications.

Having said that, it must be realized that heating and cooling of automobile seats are desirable features that have been widely adopted by automobile buyers. However, there is room for many improvements to be made on the existing systems. It would be most advantageous to update these technologies in order to provide greater comfort while utilizing less electricity, lower weights, efficiencies, new materials and technologies. Helping the transfer of heating and cooling, while minimizing moisture build up, would prove to be advantageous for any application in the seating industry.

In the construction of these aforementioned seats, a top layer of a compressible material, such as foam or felted mats, is often used for improving comfort, hiding underlying structure and providing a soft, lofted feel to the seat surface, Any compressible material generally includes trapped air within its structure to give the desired cushy feel. In that regard, common seating foams are usually constructed of a polymeric material, which unfortunately has a thermal conductivity that is generally relatively low.

This issue of low thermal conductivity has been addressed by some manufacturers with the use of a memory foam, such as a viscoelastic foam, that is filled with graphite or some other thermally conductive material. When the foam is crushed, the particles of the filler material thermally communicate with each other and transfer heat at a higher rate than with the unfilled, non-memory type foams. These foams, however, require pressure on the foam to compress it to the point that the filler material, such as graphite flakes, are in thermal communication with each other. This foam can transmit some thermal energy in points of higher contact pressure in, for example a car seat. However, lower pressure areas, like the seat back, do not transmit much heat, because they are not as compressed as those in the seat cushion.

In many modern automobiles, most seats are heated, while some are both heated and cooled. It is common in heated seats for an electrical resistance mat to be used to generate heat. Because in most systems, the electrical resistance wires in the mat are spaced apart, uniform heating is not always achieved.

On the other hand, seat cooling systems are more difficult for distribution of coolness. Where thermoelectric devices or other systems are used to provide the cooling, there is a need for better thermal distribution. Besides thermoelectric device cooling, some manufacturers have used cooling sources such as refrigerant lines, water tubes or heat pipes, and each of these methods suffer from poor thermal distribution given that the cooling lines are separated by significant distances of non-active area between the cooling lines.

It would therefore be desirable to the vehicle seating and other personal comfort heating industries if there was provided a new alternative technology for improved conductive heat and coolness transfer that could heat and/or cool a seat or seat assembly, along with a method of making the seats, or a method of using them for heating and cooling seats. It would be advantageous for the industry to review such a new technology. Certain technical benefits can be realized by the utilization of a new conductive heat/cool transfer system utilizing thermoelectric devices.

SUMMARY OF THU INVENTION

In accordance with the above-noted desires of the industry, the present invention provides various aspects, including a conductive heat/cool transfer model, a method of making it, a method of controlling same and various methods of using them for heating and cooling seats or pads. This includes a heating and cooling device, preferably a new and improved thermally conductive material for distributing the heat or coolness throughout more of the surface area. This overcomes many of the aforementioned problems with the prior art because energy consumption can be minimized, while heating and cooling distribution is maximized.

The present invention discloses a multi-component structured layer that allows the loft of the top layer of comforting foam in a seat to maintain its ability to hide underlying seat structure and provide comfort, while greatly improving thermal conductivity from a heating or cooling member to another surface such as a seat cover.

This thermally conductive layer is effective for more evenly and efficiently distributing heat and or cooling across a surface. Included in the thermally conductive layer is a source for thermal modulation including a thermal engine capable of generating heat and coolness. Further in cluded is a compressible comfort material made of a compliant material having a low coefficient of thermal conductivity with a plurality of flexible sheeted thermally conductive strips interwo ven through the compressible comfort material. In order to provide thermal distribution across the surface, the flexible sheeted thermally conductive strips are thermally coupled to the source of thermal modulation and they distribute heat and/or coolness across any desired portion of the surface.

The thermally conductive layer utilizes a source for thermal modulation that may be an active thermal engine source selected from the group consisting of thermoelectric devices, vapor compression devices, evaporative devices, fluid tubes, and electrical resistance generators. In the alternative, the thermally conductive layer may be a passive thermal engine source selected from the group consisting of phase change materials, ice, hot and cold water, and hot and cold fluids.

Regarding the compressible comfort material, it may be selected from the group consisting of foam, fibrous mats, compressible meshes, felts, fabrics, or any combination thereof. Further, the compressible comfort material may be filled with thermally conductive particles that communicate thermally upon compression, or it may be unfilled with thermally conductive particles.

The plurality of flexible sheeted thermally conductive strips includes strips of high thermal conductivity materials to distribute the heat and/or cool across the surface in an efficient and speedy manner. In that regard, the plurality of flexible sheeted thermally conductive strips include strips from 2 mm to 25 mm in width, and preferably from 5 mm. to 15 mm.

Advantageously, the plurality of flexible sheeted thermally conductive strips include fabricatable strips of thermally conductive materials. Needless to say, in automotive applications, the plurality of flexible sheeted thermally conductive strips will include sheeted materials of high thermal conductivity that are strong enough to withstand ingress and egress of an automotive seat for a very long duration.

The invention is particularly useful for applications of automotive seating, furniture seating, and recreational vehicle seating.

Although the invention will be described by way of examples hereinbelow for specific aspects having certain features, it must also be realized that minor modifications that do not require undo experimentation on the part of the practitioner are covered within the scope and breadth of this invention. Additional advantages and other novel features of the present invention will be set forth in the description that follows and in particular will be apparent to those skilled in the art upon examination or may be learned within the practice of the invention. Therefore, the invention is capable of many other different aspects and its details are capable of modifications of various aspects which will be obvious to those of ordinary skill in the art all without departing from the spirit of the present invention. Accordingly, the rest of the description will be regarded as illustrative rather than restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the nature and advantages of the expected scope and various aspects of the present invention, reference shall be made to the following detailed description, and when taken in conjunction with the accompanying drawings, in which like parts are given the same reference numerals, and wherein;

FIG. l is a perspective view of a thermally conductive layer made in accordance with the present invention;

FIG. 2A illustrates a top perspective view of a thermally conductive layer including a thermoelectric engine;

FIG. 2B illustrates a side elevational view of the thermally conductive layer including a thermoelectric engine of FIG. 2 A;

FIG. 3. is a side elevational view a thermally conductive layer of the present invention in thermal communication with a thermoelectric device;

FIG. 4 is a top plan view of a thermally conductive layer in thermal communication with a thermoelectric engine;

FIG. 5A is a front perspective view of an automotive seat application incorporating the thermally conductive layer of the present invention;

FIG. 5B is a side elevational detail of the thermoelectric engine in thermal contact with the thermally conductive layer;

FIG. 6 is a side elevational detail of a garment incorporating the thermoelectric engine in thermal contact with the thermally conductive layer;

FIG. 7 shows yet another aspect of the present invention, including a medical therapy pad utilizing the thermally conductive layer; and

FIG. 8 is a chart showing temperature rise versus time for various thicknesses of foam comfort layers incorporating the thermally conductive layer of the present invention.

DETAILED DESCRIPTION OF TUI INVENTION

Referring now to the drawings in detail, FIG.1 is a thermally conductive layer generally indicated by the numeral 10, which also includes a compressive comfort material 12 having flex ible sheeted thermally conductive strips 14 interwoven through the compressive comfort material 12.

FIG. 2A and FIG. 2B collectively illustrate a thermally conductive structure generally de noted by numeral 20, including a thermal modulation engine 22, in thermal unification with a wide sheeted thermally conductive distributor sheet 24 providing thermal communication be tween the thermoelectric engine and thermally conductive strips 28 interwoven through com pressible comfort material 26 in contact with a body contact surface, such as a fabric layer 30. The thermal modulation engine 22 may be any active source of heat and coolness, including a thermoelectric device, a vapor compression device, and eBay operative device, fluid tubes, and electrical resistance heater, or combinations thereof. Alternatively, the thermal modulation en gine may also be a passive source of heat or coolness, such as phase change materials, ice, hot and/or cold water or other hot and cold fluids. The compressive comfort material 26 may be made of any soft material including foam, fibrous mats, compressible meshes, felts, or any other suitable fabric, including combinations thereof. This soft material may be either filled or unfilled with thermally conductive particles such that, when compressed, thermal conductivity is in creased.

Still referring to FIG.'s 2 A and 2B, the thermally conductive strips 28 that are interwoven through compressible comfort material 26 may include strips of any highly conductive material, such as graphene, pyrolytic graphite, copper foil and thermally conductive polymers. These highly conductive material strips are preferably made of a material having a conductivity value of from 350 W/mk to 2000 W/mk. Body contact surface fabric 30 may be made of any suitable fabric, including woven materials, vinyl, perforated leather, or cloth. Graphene with a thermal conductivity of 500 W/mk to 2000 W/mk or pyrolytic graphite with a thermal conductivity of 350 W/mk to 1000 W/mk or other high thermal conductivity, flexible, strong and fabricatable material can be used.

FIG. 3 illustrates a first aspect of the present invention of a thermoelectric device with thermal distribution generally denoted by numeral 40. A thermoelectric engine 42 is in thermal communication with a heat sink 44 and a thermal transfer block 46 which is in thermal commu nication with a wide sheeted thermally conductive distributor 48. A compressible comfort mate rial 50 has sheeted thermally conductive interwoven strips 52, preferably graphene strips, that come into thermal contact with the wide sheeted thermally conductive distributor and then into the body contact surface fabric 54. In this fashion, the sheeted thermally conductive interwoven strips 52 bring the heat and/or coolness generated through thermal transfer block 46 up into con tact with the body contact surface fabric 54, thereby communicating the heat and/or coolness up to the body contact surface fabric 54.

FIG. 4 illustrates a preferred configuration of a heated and/or cooled conductive layer generally denoted by numeral 60, including a source of heat and coolness 62, preferably a ther moelectric engine. The source of heat and coolness 62 is in thermal communication with a wide sheeted thermally conductive distributor material 64, which in turn is in thermal communication with thermally conductive strips 66. Thermally conductive strips 66 are interwoven through a compressible comfort layer 68. As described hereinabove, compressive comfort layer 68 is preferably made of a soft material when used in any seat application.

FIG. 5A illustrates another aspect of the present invention, including an automobile seat generally denoted by numeral 70, including a seat bottom 72 and a seat that 74, providing heat and/or coolness to a seat occupant. Wide thermally conductive distributor sheets 76 are in ther mal communication with thermally conductive layer 78. FIG. 5B shows a side elevational view of the thermal engine component that provides the heat and/or coolness. In this aspect, a thermo electric engine 80 is in thermal communication between a heat sink 82 and a heat transfer block 84. Heat transfer block 84 and communicates thermal modulation to the wide thermoelectric dis tributor material 86 which is in thermal communication with thermally conductive strips 90 that are interwoven through the compressible comfort layer 88. As can be seen in this figure, heat and/or coolness is generated by the thermoelectric device 80 and through intermediate mecha nisms, thermal modulation is provided to the seat occupant.

FIG. 6 shows yet another aspect of the present invention of a heated and/or cooled gar ment generally denoted by numeral 100. Thermally conductive layer 102 is in thermal communi cation with thermoelectric heating and/or cooling engine 104 by wide thermally conductive dis tributor materials 106, thereby providing thermal comfort to the wearer of the garment by the same mechanisms as described more fully hereinabove.

FIG. 7 shows a medical therapy pad 110 in accordance with the present invention, having a therapy fabric or other material 112 that is heated or cooled by the thermally conductive layer 118. In this aspect, a thermoelectric engine 114 is again in thermal communication with a wide thermally conductive distributor material 116 to provide thermal modulation to anyone wearing the medical therapy pad 110.

While the number of applications are too numerous to discuss in this application, the following applications have been found to be advantageous. Applications of the invention include but are not exclusive of the following:

1. Automobile/truck seating

2. Office seating

3. Sport vehicle seating

4. Construction and farm equipment seating

5. Marine seating

6. Home seating

7. Hospital seating

8. Hospital beds

9. Home beds

10. Pet beds

11. Baby car seats

12. Heated and/or cooled garments

13. Heating pads

14. Organs for transplantation requiring cooling during transport

15. Delicate items for transport that must be kept at certain temperatures 16. Fragile food products requiring heating or cooling

17. Heated/cooled cupholders that maintain a compressive force on the beverage container while still heating or cooling them

Generally, this invention would be used to transmit thermal energy from the heated or cooled surface from the heat or cool source through a material, such as a comfort foam pad, to the other side of this material and also transmit thermal energy laterally to areas on the surface intended to be thermally conditioned. The heat or cool source is transmitted via a flexible thermally conduc tive layer. In applications where direct contact with the ice may cause harm to the object being cooled, the present invention provides for a soft and compliant interface between the ice and the ob ject being cooled. A specific example of this is the use of cooling pads directly contacting human or animal skin, or even for transportation of human organs.

The thermally conductive layer of the present invention provides a connected pathway for thermal energy to pass from one side to the other of a soft and compliant compressible comfort layer material. In addition, it does not require compression of the material to become effective like the prior art filled viscoelastic foams. Nor does it rely on filling the base material with a thermally conductive material. Virtually any durometer foam, whether thermally conductive or insulative, can take advantage of the present invention. Materials other than foam that are used in seating and other applications will perform the same function as the foam described here.

The amount of heat transferred can easily be adapted for any end use by increasing or decreasing the width of the thermally conductive graphene strips or the thickness of the strips. The strips can be wide or they can be thin. A range of widths may be from 25mm to 2mm, although other widths may be used depending on the application. As such, materials incorporating thermally conductive means do not have to be formulated or woven with conductive fibers. Standard, common materials can be made thermally conductive in the X, Y and Z planes.

A significant benefit disclosed herein is that the thickness of the soft, compliant compressible comfort layer can vary greatly without changing the overall heat transfer. Due to the highly thermally conductive strips interwoven through the compressible comfort layer material, thermal energy is transferred 3mm up to 25mm, which is the thickness of a conventionally used soft, compliant compressible comfort layer material. In prior art assemblies, where materials having thermal conductivities of 3 - 10 W/m², the thickness of the compliant layer significantly impacts the heat transfer.

In a controlled test between 1.) a prior art thermally filled viscoelastic foam and 2.) a viscoelastic foam of the same thickness with the instant woven graphene strips feature, the thermal conductivity of the foam that included the woven thermally conductive strip feature was improved by 85%.

FIG. 8 is a chart of the results of tests performed on several layers of compressible comfort material with thermally conductive particle filled memory foam in addition to memory foam using the concept of this patent application. The results indicate a clear and substantial improvement in thermal conductivity using the new invention. The test was done using a thermal test stand that uses a thermoelectric cooling system to cool a strip of graphene. On top of the graphene strip is a layer of memory foam to be tested and on top of that, a layer of automotive seating vinyl. Thermocouples placed on top of the graphene strip and on top of the vinyl seating material are used to measure the difference in temperature between the two. The lower the temperature difference, the higher the overall thermal conductivity.

Still referring to FIG. 8, test results of time (minutes) vs. temperature (°C) are graphed for an experiment where a weight that exerts lpsi of force is used to compress the foam. The foam is compressed at about the same force as the average of a person sitting on a seat. Even with the filled foam operating at its optimal compression performance of the 6mm foam was improved by 45%. If the foam is not compressed or lightly compressed, as in a car seat back, the improvement was found to be substantially more.

The chart of FIG. 8 shows results of testing in the above noted manner for five different configurations of seat cover and foam layers. The test included the system described above with just a layer of seat vinyl, seat vinyl + 3mm viscoelastic foam, seat vinyl + 3mm viscoelastic foam that has been altered to become the thermally conductive layer (TCL), seat vinyl + 12mm viscoelastic foam and seat vinyl + 12mm viscoelastic foam that has been altered to become the TCL. The thicker 12mm foam, even in a compressed state has high thermal impedance (low thermal conductivity). However, the 12mm TCL, shows remarkably higher relative thermal conductivity.

FIG. 8 reflects the difference in temperature (DT) between the graphene and the seat cover outer surface, ie. That which would thermally contact a seat occupant. The greater the difference between the graphene temperature and the vinyl seat surface temperature, the greater the thermal resistance and the smaller the temperature difference, the lower the thermal resistance, ie. higher thermal conductivity.

As can be seen by the chart of FIG. 8, the 3mm TCL and the 12mm TCL show great improvement in thermal conductivity, while still maintaining the soft attributes of the foam for comfort and hiding of underlying structures. At the 16.5 minute mark, the 12mm TCL shows an 85% improvement in temperature difference versus the 12mm foam of the same composition. The 3mm TCL shows a 25% improvement versus the 3mm foam.

Therefore, these tests show that more heat is transferred to and from the thermally conductive graphene layer to and from the seat occupant. The result for the seat occupant is greater thermal comfort and the ability to heat and cool a seat occupant under more extreme ambient thermal conditions. In addition, because heat transfer is increased, less energy is required to exchange the same quantity of heat in and out of the body.

In summary, numerous benefits have been described which result from employing any or all of the concepts and the features of the various specific aspects of the present invention, or those that are within the scope of the invention.

The foregoing description of a preferred aspect of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the inven tion to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings with regards to the specific aspects. The aspect was chosen and described in order to best illustrate the principles of the invention and its practical applications to thereby en able one of ordinary skill in the art to best utilize the invention in various aspects and with vari ous modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims which are appended hereto.

INDUSTRIAL APPLICABILITY

The present invention finds utility in the automotive seating market for better heat and coolness distribution across a surface contacting and comforting a person, office furniture seating, medical therapy pads having thermal properties, incorporation into a garment for comforting an occupant, among many other applications.

Claims

CLAIMS What is claimed is:

1. A thermally conductive layer for more evenly and efficiently distributing heat and or cooling across a surface, comprising: a source for thermal modulation including a thermal engine capable of generating heat and coolness; a compressible comfort material made of a compliant material having a low coef ficient of thermal conductivity; and a plurality of flexible sheeted thermally conductive strips interwoven through the compressible comfort material, said flexible sheeted thermally conductive strips being thermally coupled to the source of thermal modulation and distributed across the desired portion of the surface.

2. The thermally conductive layer of claim 1, wherein the source for thermal modulation may be an active thermal engine source selected from the group consisting of thermoelectric devices, vapor compression devices, evaporative devices, fluid tubes, and electrical resistance generators.

3. The thermally conductive layer of claim 1, wherein the source for thermal modulation may be a passive thermal engine source selected from the group consisting of phase change materials, ice, hot and cold water, and hot and cold fluids.

4. The thermally conductive layer of claim 1, wherein the compressible comfort material is selected from the group consisting of foam, fibrous mats, compressible meshes, felts, fabrics, and combinations thereof.

5. The thermally conductive layer of claim 1, wherein the compressible comfort material may be filled with thermally conductive particles that communicate thermally upon compression.

6. The thermally conductive layer of claim 1, wherein the compressible comfort material may be unfilled with thermally conductive particles.

7. The thermally conductive layer of claim 1, wherein the plurality of flexible sheeted thermally conductive strips include strips of high thermal conductivity materials.

8. The thermally conductive layer of claim 1, wherein the plurality of flexible sheeted thermally conductive strips include strips from 2 mm to 25 mm in width.

9. The thermally conductive layer of claim 1, wherein the plurality of flexible sheeted thermally conductive strips include fabricatable strips of thermally conductive materials.

10. The thermally conductive layer of claim 1, wherein the plurality of flexible sheeted thermally conductive strips include sheeted materials of high thermal conductivity that are strong enough to withstand ingress and egress of an automotive seat for a very long duration.