DESC:FIELD OF THE INVENTION:
[0001] The present invention generally relates to heat transfer in applications involving electric motors. More particularly, the present invention relates to an enhanced structure of thermal interface material used in electronic components to improve heat transfer and thermal dissipation in electric motors.

BACKGROUND
[0002] Power electronic circuits play a major role in controlling and converting electric power in a wide range of applications, including renewable energy systems, electric vehicles, industrial automation, and consumer electronics. These power electronic circuits primarily utilize solid-state switching components such as diodes, thyristors and transistors like MOSFETs, IGBT etc. to switch and control the electrical energy and to provide precise and reliable power management solutions. These switching components are integrated as a circuit on a printed circuit board (PCB). During control / conversion operations, these solid-state switching components generate heat which is absorbed by a heat sink in the circuit. However, to enhance heat transfer, a thermal interface material (TIM) is utilized to improve the thermal contact and conduction between the heat generating electronic components, such as the power devices or heat sinks, and their mounting surfaces. TIM is generally located between the heat-generating component and the heat sink or mounting surface.

[0003] Several prior arts which disclose the structure and preparation of thermal interface material for improving the heat dissipation, have been provided below.

[0004] For example, United States Patent Number 11510342 to Ching-Ming Yang et.al., entitled “Immersion heat dissipation structure” relates to a heat dissipation structure. The immersion heat dissipation structure comprises a porous metal heat dissipation material, an integrated heat spreader, and a thermal interface material. The thermal interface material is arranged between the porous metal heat dissipation material and the integrated heat spreader to form a thermal connection. Also, a super-wetting layer is formed on a connection surface between the porous metal heat dissipation material and the thermal interface material.

[0005] PCT Application Number 2020119580 to Zhang Baotan et. al., entitled “Organosilicone-graphite composite thermal interface material, preparation method therefor and application thereof” relates to the preparation method of an organosilicon-graphite composite thermal interface material. The organosilicon-graphite composite thermal interface material comprises a graphite skeleton which has a honeycomb structure filled with an organosilicone material. This material retains the softness and conformability of the organosilicon and also has good thermal conductivity of the graphite skeleton. The thermal interface material has higher longitudinal thermal conductivity at a lower filling density. The honeycomb structure improves the tensile strength of the organosilicon material and prolong the service life in severe environments.

[0006] The thermal interface material in the existing prior arts is a flat, plain single sheet which transfers heat from the heat generating electronic components in the PCB. As the existing TIM sheet is plain, the thermal conductivity is relatively lower due to surface roughness, warpage of plane surface, etc and also requires machining to improvise the structure of the TIM material. Further, the TIM sheet is very closely adhered or bonded to the heat emanating component and hence, there is no gap between the TIM sheet and mounting surfaces. Additionally, during the compression of the TIM sheet between heat-generating component and heat sink, the conduction adhesive or grease overflows towards the sides of the sheet. This results in poor conduction and reduced heat transfer.

[0007] Hence, there is a need for an improved thermal interface material sheet which enables an enhanced heat transfer from the heat generating electronic components. The present invention, therefore, proposes a thermal interface material (TIM) sheet with a modified structure that enhances the heat transfer between solid-state switching devices and power devices in the printed circuit board (PCB) of power electronic circuits.

OBJECTIVES OF THE INVENTION
[0008] A primary objective of the present invention is to provide a thermal interface material (TIM) sheet comprising an interwoven mesh structure or twill weave pattern on one side/ surface of the thermal interface material, and the other side/surface of the TIM material is a standard planar adhesive structure.

[0009] Another objective of the present invention is to provide a thermal interface sheet material wherein the interwoven mesh structure or twill weave pattern includes airgaps, thereby featuring a porous structure.

[0010] Another objective of the present invention is to provide a thermal interface sheet material that is inserted between a solid-state component/ electronic component mounted on a printed circuit board (PCB) and a heat sink or a heat distributing medium.

[0011] Another objective of the present invention is to provide a thermal interface sheet material, wherein upon compression of the sheet between the electronic components and a heat sink structure or a heat distributing medium, an even flow of a thermally conductive adhesive or thermal grease through the porous structure is ensured, thus enhancing thermal conduction.

[0012] Another objective of the present invention is to provide a thermal interface sheet material having an increased surface area for enhancing heat transfer from the electronic components mounted on the printed circuit board (PCB) of an electric vehicle motor, thereby improving the overall heat dissipation efficiency.

[0013] Another objective of the present invention is to provide better conduction and better stability during the compression of the TIM material between the electronic component and the heat sink or heat distributing medium.

[0014] Other objects of the present invention, as well as particular features, elements and advantages thereof, will be clarified in or be apparent from the following description and the accompanying figures.

SUMMARY
[0015] The following summary is provided to facilitate a clear understanding of the new features in the disclosed embodiment and it is not intended to be a full, detailed description. A detailed description of all the aspects of the disclosed invention can be understood by reviewing the full specification, the drawing and the claims and the abstract, as a whole.

[0016] To achieve the above-mentioned objectives, the present invention discloses a thermal interface material (TIM) sheet which includes an interwoven mesh structure or twill weave pattern for enhanced heat transfer between electronic components.

[0017] According to an embodiment of the present invention, the thermal interface material (TIM) sheet of the present application is placed between the heat generating solid-state/electronic components mounted on a printed circuit board (PCB) and a heat sink structure or a heat distributing medium to transfer heat. The interwoven mesh structure or twill weave pattern structure of the thermal interface material (TIM) sheet is formed by using two yarns or strands of thermal conductive materials alternated in a specific pattern to create a mesh structure. This mesh structure further includes air gaps providing a porous structure for better thermal conduction and stability during a compression of the TIM sheet, when placed between the solid-state/electronic components of the PCB and the heat sink.

[0018] In accordance with the embodiment of the present invention, one side or a top layer of the TIM sheet facing the electronic component is configured as the inter-woven mesh structure for all uneven surfaces and the other side or the bottom layer is configured as a standard planar adhesive structure.

[0019] According to an alternate embodiment of the present invention, the interwoven or twill weave patterned TIM material is placed between the heat generating / producing electronic components mounted on the PCB and a heat distributing medium such as a rear housing of an electric vehicle (EV) motor. Furthermore, according to the alternate embodiment, the rear housing of the electric motor vehicle acts as a cooling chamber, but not limited to the same. The interwoven mesh structure or twill weave pattern of the TIM sheet enhances heat transfer of energy thereby increasing the surface area of transfer between a unmachined rough surface to the PCB component surface.

[0020] Additionally, the rear housing of the electric motor vehicle incorporates an isolated chamber comprising a high-pressure liquid (usually oil) with heat transfer properties, flowing through the stator and rotor of the electric vehicle (EV) motor, leveraging the liquid's heat transfer properties to manage thermal energy effectively.

[0021] Overall, the improved configuration of the thermal interface material sheet as well as the other features of the present application enhances heat transfer in the mounted electronic components of the electric vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS:
[0022] The detailed description is described with reference to the accompanying figures. Throughout the drawings, the same drawing reference numerals will be understood to refer to the same elements and features. The features and advantages of the present proposed system will become more apparent from the following detailed description a long with the accompanying figures, which forms a part of this application.
FIG. 1 illustrates the conventional / regular thermal interface material (TIM) sheet with plain sheet structure according to prior art.

FIG. 2 illustrates an arrangement/configuration of the TIM sheet with interwoven mesh structure according to a preferred embodiment of the present invention.

FIG. 3 illustrates the top and bottom layers of the TIM sheet according to the preferred embodiment of the present invention.

FIG. 4 illustrates the exemplary arrangement of printed circuit board (PCB) with solid-state/electronic components, TIM sheet and electric vehicle motor rear housing according to an alternate embodiment of the present invention.

REFERENCE NUMERALS:
1 – Solid-state components/ electronics component
2 – thermal interface material (TIM) sheet
3 – Heat Sink
4 – Top layer of TIM sheet comprising interwoven mesh structure
5 – Bottom layer of TIM sheet comprising planar adhesive structure
6 – Electric vehicle motor rear housing / isolated chamber
7 – PCB mounted with heat producing electronic components
8 – top layer of TIM sheet
11 – conventional thermal interface material (TIM) sheet
12 – Solid-state component/ electronics component
13 – Heat Sink
14 – Configuration of conventional TIM sheet

DETAILED DESCRIPTION OF THE INVENTION
[0023] The following is a detailed description of the present disclosure depicted in the accompanying drawings. However, it may be understood by a person having ordinary skill in the art that the present subject matter may be practiced without these specific details. The subject matter of the disclosure will be more clearly understood from the following description of the embodiments thereof, given by way of example only with reference to the accompanying drawings, which are not drawn to scale.

[0024] If the specification states that a component or a feature “may” or “can” be included, that particular component or feature is not required to be included or have the characteristic. The use of open-ended terms like “comprising” and variations herein is meant to encompass the steps listed thereafter and equivalents thereof as well as additional items. As used herein, the singular forms “a,” “an,” and “the” designate both the singular and the plural, unless expressly stated to designate the singular only.

[0025] The term EV refers to “electric vehicle”. The term PCB refers to “printed circuit board’, which is a medium used to connect or "wire" components to one another in a circuit. The term “improved” and “modified” has been used interchangeably. Ther term “TIM sheet” refers to thermal Interface Material (TIM) sheet, utilized for efficient heat transfer. The term “TIM sheet” and “thermal dissipation pad” is used interchangeably here. In accordance with the present invention, the electric component can also be termed as heat generating component, heat producing component, solid-state switching component, solid-state electronics/element, energy converting device etc., but not limited to the same.

[0026] The present invention relates to an improved structure of a thermal interface material (TIM) for enhanced heat transfer in electronic components. The thermal interface material sheet of the present invention comprises an interwoven mesh structure or twill weave pattern on a outer/upper surface of the sheet for enhanced heat transfer in electronic components.

[0027] Fig.1 discloses a conventional / regular thermal interface material (TIM) sheet (11) according to prior art which is integral to the PCB (Printed Circuit Board) (not shown) of an electric vehicle. Furthermore, the configuration of the thermal interface material (TIM) sheet (11) is a plane sheet structure. According to Fig.1, the conventional TIM (11) is sandwiched between the solid-state/electronic components (12) of the PCB and a heat sink (13) of the electric vehicle. Moreover, the regular TIM sheet (11) is closely adhered or bonded to the PCB (not shown) of the motor, without leaving any gap between the adhered surfaces. The TIM sheet (11) provides efficient thermal management by enhancing heat transfer between electronic/solid-state components (12) and heat sinks (13), preventing overheating. This plain, flat configuration (14) as seen in Fig.1, allows for easy customization and application, ensuring optimal cooling performance. This helps maintain the reliability and efficiency of the vehicle’s electronic systems, crucial for its overall performance and safety. However, the closely bonded TIM sheet (11) does not ensure an even distribution of the thermally conductive adhesive or thermal grease. Instead, when the conventional TIM (11) is compressed, the thermal conductive adhesive or grease tends to overflows from the sides, leading to inefficiencies in thermal conduction.

[0028] Fig,2 discloses a TIM (thermal interface material) sheet (2) according to an embodiment of the present invention. Referring to Fig.2, the thermal interface material (TIM) sheet (2) is inserted between a solid-state / electronic component (1) of the PCB (printed circuit board) and a heat sink (3) within the motor of the electric vehicle. The TIM sheet is positioned to facilitate a heat transfer between the solid-state component and the heat sink. Furthermore, the proposed TIM sheet (2) features an interwoven mesh structure (4) on one side of the sheet. Furthermore, the interwoven mesh structure may face the electronic components mounted on the PCB, as shown in Fig.2 or the heat sink (3). Additionally, this mesh structure is porous, containing air gaps. These air gaps in the mesh structure facilitates an even distribution of the thermally conductive adhesive, or thermal grease, thereby, reducing overflow of the same and ensuring better stability during the compression of TIM sheet (2) when it is placed between the solid-state/electronic component (1) and the heat sink (3).

[0029] Fig.3 further illustrates a configuration of the proposed thermal interface material (TIM) sheet (2) according to an embodiment of the present invention The TIM sheet (2) comprises a top layer (8) and a bottom layer (5) as shown in FIG. 3. The top layer (8) of the TIM sheet (2) is configured as an interwoven mesh structure (4) or twill weave pattern (not shown) which is a more porous structure with air gaps. The interwoven mesh structure (4) is formed by two strands of thermally conductive material forming a series of interlocking loops. Even though the interwoven mesh structure (4) and/or the twill weave pattern (not shown) are two different types of weave structures with distinct patterns, both of these patterns have two yarns which are woven in crisscross structure. In the present invention, the interwoven mesh structure (4) and the twill weave pattern comprises a common crisscross structure of two or more yarns of thermally conductive material.

[0030] Hence, the interwoven mesh structure (4), enables an increase in the surface area available for heat transfer from the PCB component and the TIM sheet.

[0031] Referring back to Fig.3, the interwoven mesh structure (4) or twill weave pattern structure is made up of two thermal interface material yarns that are woven in a specific pattern of two interlacing layers arranged at right angles to each other, forming a mesh structure. This mesh structure includes air gaps between the horizontal and vertical interlacing layers, which act as porous areas that aid in heat transfer. Additionally, the bottom layer (5) of the thermal interface material (TIM) sheet (2) is configured as a standard planar adhesive structure, and the top layer (4) is arranged over the bottom layer (5) as shown in FIG. 3. Furthermore, the mesh structure is composed of a material selected from the group consisting of high thermal conductivity polymers or other thermally conductive materials such as silicon film, silicon fiberglass, silicon-based cloth or paraffin wax based materials, thereof.

[0032] FIG. 4 discloses a typical arrangement of solid-state/ electronic components mounted on a printed circuit board (PCB) (7), with a thermal interface material (TIM) sheet featuring the interwoven mesh structure (4), placed between the PCB and a heat distributing medium such as the rear housing(6) of an electric vehicle motor The heat-generating components on the PCB (7), can either face the interwoven mesh structure (4) of the TIM sheet (2) as seen in Fig.4 or the heat distributing medium. Fig.4 further discloses that the rear motor housing (6) is an isolated chamber (not shown) comprising a high-pressure liquid (usually oil) which has heat transfer properties and flows through the stator and rotor of the electric motor. This isolated chamber is the enclosed motor housing (6) structure of any rotating machines. Additionally, there is an energy converting device (not shown) which is controlled by the electronic components mounted on the printed circuit board (PCB) (7) and emanates heat during operation. The isolated chamber/motor housing (6) is separated from the PCB device by a thermally conductive material cover (not shown) by which heat is then conducted through the TIM sheet (2).

[0033] It is observed that the interwoven mesh surface (4) of the thermal interface material (TIM) sheet (2) is not tightly bonded to the heat-emitting component. This surface combined with the airgaps within its porous structure, creates a gap between the TIM sheet and the mounting surfaces. Consequently, during the compression of the TIM sheet between the heat-generating components and the heat sink (3) or a motor housing (6), the conductive adhesive or grease remains within the mesh and does not overflow from the sides of the sheet.This ensures proper conduction and enhanced heat transfer by maintaining effective contact and preventing leakage.

[0034] Referring back to Fig.4, during compression of the TIM sheet (2), the conductive adhesive or grease flow through the air gaps of the porous structure present on the interwoven mesh structure (4). Hence, the present invention provides better thermal conduction resulting in better thermal transfer. The air gap in the interwoven mesh structure (4) or twill weave pattern provides better stability during compression of TIM sheet (2) which is placed between the solid-state component (1) and the heat sink (3) or any heat distributing medium such as the motor housing (6).

[0035] Referring to Figs. 2 to 4, , the solid-state components (1) mounted on the printed circuit board (PCB) (7) includes MOSFETs, IGBT drives, thyristors or any solid-state switching components and other heat-generating electronic components, according to a preferred embodiment of the present invention. Moreover, in an exemplary embodiment, the heat sink (3) is made up of metal, but not limited to the same. Furthermore, referring to Figs 2 to 4, the interwoven mesh structure (4) or twill weave pattern of the thermal interface material (TIM) sheet (2) can be made of any suitable conductive material that withstand high temperatures and transfer heat in particular speed.

[0036] Thus, the thermal interface material (TIM) sheet (2) proposed in the present invention enables an enhanced heat transfer of energy by means of an interwoven mesh structure (4) or twill weave pattern by increasing the surface area of heat transfer between an unmachined rough surface and the PCB component surface.
,CLAIMS:I/WE CLAIM:
1. An arrangement for a thermal interface material (TIM) sheet (2) for heat transfer of electronic components (1), comprising:
a. the said electronic components (1) mounted on a printed circuit board (PCB) (7);
b. a heat sink (3) or a heat distributing medium placed in contact with the thermal interface material (TIM) sheet (2) sheet; and
c. the thermal interface material (TIM) sheet (2) sandwiched between the said electronic components (1) and the said heat sink or heat distributing medium;
wherein the said thermal interface material (TIM) sheet (2) comprises:
a top layer (8) and a bottom layer (5); and
the top layer (8) is configured as an interwoven mesh structure (4) featuring a porous structure with air gaps;
such that, upon compression of the said thermal interface material (TIM) sheet (2), a thermally conductive adhesive or thermal grease flows through the porous structure, thereby enhancing thermal conduction.

2. The arrangement as claimed in claim 1, wherein the bottom layer (5) is configured as a planar adhesive structure.

3. The arrangement as claimed in claim 1 wherein the said thermal interface material (TIM) sheet (2) features a twill weave pattern structure.

4. The arrangement as claimed in claim 1 and 3 wherein the interwoven mesh structure (4) or the twill weave pattern structure is configured as a crisscross structure of two or more yarns of a thermally conductive material.

5. The arrangement as claimed in claim 1 and 4, wherein the thermally conductive material of the mesh structure (4) is selected from a group consisting of high thermal conductivity polymers or other thermally conductive materials such as silicon film, silicon fiberglass, silicon-based cloth or paraffin wax based materials, thereof.

6. The arrangement as claimed in claim 1, wherein the electronic components (1) comprise MOSFETs, IGBT drives, thyristors or any solid-state switching components and other heat-generating electronic components.

7. The arrangement as claimed in claim 1, wherein the electronic components (1) on the PCB (7) control an energy-converting device wherein said energy-converting device generates heat during operation.

8. The arrangement as claimed in claim 1, wherein the porous structure of the interwoven mesh structure (4) ensures an even distribution of the thermally conductive adhesive or thermal grease, and mitigates overflow, during the compression of the thermal interface material (TIM) sheet (2).

9. The arrangement as claimed in claim 1, wherein the said porous structure of the mesh structure (4) provides stability and uniformity during the compression of the thermal interface material (TIM) sheet (2).

10. A method for heat transfer in electronic components (1) utilizing an arrangement of a thermal interface material (TIM) sheet (2), comprising steps of:
a. mounting the electronic components (1) on a printed circuit board (PCB) (7); and
b. placing a heat sink (3) or a heat distributing medium in contact with the thermal interface material (TIM) sheet (2); and
c. sandwiching the thermal interface material (TIM) sheet (2) between the electronic components (1) and the heat sink or heat distributing medium;
wherein the method includes:
providing the said thermal interface material (TIM) sheet (2) with a top layer (8) and a bottom layer (5), the top layer (8) configured as a interwoven mesh structure (4) featuring a porous structure with air gaps; and
compressing the said thermal interface material (TIM) sheet (2) to allow a thermally conductive adhesive or thermal grease to flow through the porous structure, thereby enhancing thermal conduction.