Problems and Solutions for Automotive Heat Management Systemsspeautomotive.com/wp-content/uploads/2018/03/TP... · Design Considerations ‒Materials are the primary determinant of

Thermally Conductive Thermoplastics

Problems and Solutions for Automotive Heat Management Systems

Darin Grinsteinner Product Development

Celanese Engineered Materials

© Celanese Corporation 2017

Contents

►Demand in Automotive Applications for Thermal Conductivity (TC)

►Design Considerations in Heat Dissipation Applications

►Material solutions with Thermally Conductive Thermoplastics

Message #1 TC materials are not as brittle as they once were.

Message #2 TC materials are multifunctional.

External / Thermally Conductive Thermoplastics 2

Demand for Thermal Conductivity

Thermal Management needs in Automotive


Demand in Automotive

Considerations for Heat Management in Autos

► Under the Hood/Engine Environment

‒ Road Surface Heat ~ 70ºC

‒ Engine Proximity Temperatures ~ 120-180ºC

‒ Exhaust System >300ºC

‒ Other Issues: Friction, voltage spikes, thermal shock, thermal cycling, etc.

► Electronic Environments

‒ Engine Control Modules, Power Control Modules, HEV Motor Controllers

‒ 85-125ºC Operating Temperature / 10-5000W Thermal Power Dissipation

‒ Ignition Modules & Voltage Regulators

‒ 120-140ºC Operating Temperature & ~ 10W Thermal Power Dissipation

‒ Battery Trays/Carriages

‒ Multimedia Devices, Radio Receivers




Focal Applications of Thermally Conductive Polymers

► Lighting Systems

‒ LED systems (Temperature Resistances 200-220ºC)

‒ Heat Sinks

‒ Frames

‒ Housings (Light housings & ECU housings)

‒ Reflectors

‒ Brackets

► Battery Modules (Holders, Trays, Pads)

‒ Balance of Needs

‒ Heat Dissipation

‒ Chemical Resistance

‒ Electrical Management




►Value Drivers for TC Polymers

1. Weight Reduction/Fuel Consumption

‒ Metal Lighter TC Polymers

2. Heat Management/Reliability

‒ Better heat dissipation means longer component life.

3. Corrosion Resistance

‒ Polymers usually have the advantage over metals.

4. Aerodynamics (Fuel Consumption & Style)

‒ Reduced space under the hood means components harder to cool.

‒ Metals not as easy to tailor TC properties to diverse components as polymers.


Design

Considerations when designing components for thermal management


Design Considerations

► 3 Basic Principals in Designing Optimum Heat Sinks

1. Maximizing heat transferred to the ambient.

2. Spread the heat from the source across the heat sink.

3. Make the heat sink as light and compact as possible.

Improved Design 15º temp. drop




► Heat Transfer Mode

‒ Conduction

‒ Convection (free air

or forced air)

‒ Radiation

► Shape

‒ Dimensional Space

‒ Thicknesses

Computer Aided Engineering (CAE) tools are typically used to optimize shape with heat transfer modes.


Computational Fluid Dynamic (CFD) Model of a typical heat sink.


gate

“in plane”

Lab Measurement In-plane Thru-plane

Conductivity 27-31 W/m/K 4-5 W/m/k

“thru-plane”

Like most composite material properties, the thermal conductivity of the composite material will be anisotropic in the molded article.

External / Thermally Conductive Thermoplastics

Design: Materials are Anisotropic

10



11

► Thermal ‒ Continuous use temperature & maximum

temperature.

‒ Temperature reduction/dissipation needed.

► Electrical Conductivity ‒ Sensitivity to electrical leads.

‒ Electrically insulative / dielectric.

►Materials ‒ Thermal conductivity should be treated like any

other polymer property and not specified beyond what is needed.

‒ Specifying the thermal conductivity beyond what is needed can add cost and weight.

IR intensity Plot of plaques mounted to a 5W

heater. Conventional Plastic (Left Plaque).

Thermally Conductive Plastic (Right Plaque)

ΔT = 24ºC ΔT = 4ºC


Materials

Solutions for thermal management


Material Solutions: How TC Polymers can replace metal

► The resistance to heat transfer equals the sum of the resistances to conduction and convection

‒ R total = R conduction + R convection

► Model of heat transfer (1-dimensinonal) across a flat plate for a fixed power output.

‒ Situations where conduction is the limiting factor

‒ TC Polymer = 1.0 gains significant benefits from initial TC = 0.1

‒ TC Polymer = 10 would be just as efficient as Aluminum with TC = 100



Materials: Thermal Conductivities

Material of Construction is the Primary Determinant in Thermal Conductivity

Thermally conductive plastics/polymers have positioned themselves to compete with historical metals such as Aluminum


Material Thermal Conductivity (W/m*K)

Unfilled Plastics ~ 0.2

Thermoset Resins 0.2 - 1.4

Stainless Steel 15-30

Thermally Conductive Plastics/Polymers

~ 0.5 - 40

Aluminum 90-150

Copper 300-400

ASTM E1461 Laser Flash method to

determine thermal conductivity.


Materials: TC Plastic benefits

► In-house molding vs. outsourced metal fabrication

‒ In-house Injection molding capabilities are common in automotive.

► Net-shape Molding & Design Flexibility

‒ Complex Geometries

‒ Part Consolidation

‒ High Speed Manufacturing

► Density

‒ Thermally Conductive Plastic Grades ~1.2- 2.0 g/cc (Aluminum = 2.7g/cc)

► Wide Range of TC performance

‒ Thermally conductive fibers and fillers can increase the thermal conductivity of a plastic by up to 500 times!

‒ CoolPoly® TCP E grades 1-40 W/m*K (Electrically Conductive)

‒ CoolPoly® TCP D grades 1-14 W/m*K (Dielectric)



Materials: Value behind CoolPoly® TCP

►Needs:

‒ Thermal Conductivity

‒ Static Dissipation

‒ Heat Resistance

‒ Heat Stability

‒ Mechanical Strength

‒ UV Resistance

‒ Electrical Isolation

‒ Weldable

‒ Laser Markable

‒ Metallization

‒ Non-flammable

• CFD

• Mold filling

• Prototyping

• Molding

• Thermal

• Mechanical

• Analytical

• Electrical

• Long & short fibers

• Particles & powders

• Conductive vs. Non

• Global

• PPS

• PEEK

• Nylon

• Elastomers

• Etc. Base Resin Chemistry

Large TC Functional

Filler & Fiber Supply

Base

CAE & Tooling Design

Capabilities

In-house Testing

capabilities

Compounding



Materials: Property Profile – Toughened Nylon

► Heat High & Thermal Conductivity

► Uses: LED Headlamp Heat Sinks, ECU’s

Toughness improved by 1.5-2x without sacrifice to thermal conductivity or density + added UV stability

Thermally Conductive Thermoplastics 17

New Toughened Nylon Grade ► High Thermal Conductivity, Tough Nylon,

UV Stable (exterior components)

► Uses: Heat Sinks, Brackets, Housings Property Existing New

Density (g/cc) 1.6 1.6

Flexural Strength (MPa) 60 100

Flexural Modulus (GPa) 7 14

Charpy UnNotched Impact (kJ/m2)

4 9

Thermal Conductivity In-Plane (W/m*K)

21 21

UV: ISO 4892-2 @1250Hrs 4-5

Volume Resistivity (ohm-cm) <1 <1

Surface Resistivity (ohms) <1 E3 <1 E3

Existing Nylon Grade


Improving UV resistance over an existing grade

Existing polyamide TC toughened polyamide

0hr 750hr (1377 kJ/m2) 0hr 750hr (1377 kJ/m2)



Materials: Property Profile – Toughened TC Dielectric Grade

Toughness improved without sacrifice to thermal conductivity density or resistivity.

Thermally Conductive Thermoplastics 19

► High Heat, Dielectric, Low Cost

► Uses: Electric Motors, Temp. Sensors, Bobbins, EV Battery Modules

► Toughened PPS, Insulative, Dielectric, High Heat, Low Cost

► Uses: Battery Modules, Electronic components

Property Existing New

Density (g/cc) 2 2

Tensile Strength (MPa) 125 144

Flexural Modulus (GPa) 18 26

Charpy Notched Impact (kJ/m2)

2 9

Thermal Conductivity In-Plane (W/m*K)

1 1

Volume Resistivity (ohm-cm)

>10e13 >10e13

Existing TC Dielectric PPS Toughened TC Dielectric PPS


Summary

► Demand for Thermal Conductivity in Automotive

‒ Heat Dissipation is a critical aspect to reliability and performance

► Design Considerations

‒ Materials are the primary determinant of how heat will be managed.

‒ No need to over-specify your thermal conductivity.

► Material Solutions

‒ Developments in new plastic formulations are allowing designers to tailor properties to part needs.


20

Message #1 TC materials are not as brittle as they once were.

Message #2 TC materials are multifunctional.


Questions?

Thank You! Contact Information:

Darin Grinsteinner Product Development

Celanese International

8040 Dixie Highway

Florence, KY 41042

Office Phone +1-859-372-3168

[email protected]



Disclaimer

Disclaimer

This publication was printed on 20 July 2017 based on Celanese’s present state of knowledge, and Celanese undertakes no obligation to update it. Because conditions of product use are outside Celanese’s control, Celanese makes no warranties, express or implied, and assumes no liability in connection with any use of this information. Nothing herein is intended as a license to operate under or a recommendation to infringe any patents.

Celanese®, registered C-ball design and all other trademarks identified herein with ®, TM, SM, unless otherwise noted, are trademarks of Celanese or its affiliates.

Copyright © 2017 Celanese or its affiliates. All rights reserved.

Contact Information

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Product Information Service t: +1-800-833-4882 t: +1-859-372-3244

Customer Service t: +1-800-526-4960 t: +1-859-372-3214 e: [email protected]

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Product Information Service t: +(00)-800-86427-531 t: +49-(0)-69-45009-1011

e: [email protected]

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Customer Service t: +86 21 3861 9266 f: +86 21 3861 9599 e: [email protected]

External / Thermally Conductive Thermoplastics END

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