Date post: | 05-Feb-2018 |
Category: |
Documents |
Upload: | nguyenliem |
View: | 229 times |
Download: | 2 times |
Stanyl® TC
Copyright © DSM Engineering Plastics 2010
Thermally conductiveplastics in LED lamps
Rob Janssen, Lucien Douven, Abel Pot, Hans van Dijk
Thermally conductive plastics
Copyright © DSM Engineering Plastics 2010
DSM Engineering Plastics - Stanyl® TC Unlimited. DSM
LED is the lighting solutions of the future. Current lightingapplications are designed with this new LED technology.Stanyl TC is the best long term solution offeringproductivity gains, resulting in energy savings, coast andmaterial reduction.
Scope
Trends in the market of lighting solutions
Stanyl TC, the plastic solution for LED applications
How does it work
Application examples
Proven thermal management: the measurements
Conclusion
Contact
Appendix
DSM Engineering Plastics - Stanyl® TC
Trends in lighting applications
To leverage existing lighting infrastructure, LED retrofit lamps have beendeveloped. They allow LED bulbs to be substituted for incandescent, halogenor fluorescent bulbs in existing lighting infrastructure.The significant benefits of LED Lighting – energy savings, longer life, higherefficiency and reduced environmental impact – as well as new legislation areencouraging consumers to replace conventional lighting lamps with high-power LED lamps.
DSM Engineering Plastics - Stanyl® TC
Stanyl TC in LED applications
Trends:
Application:
Features:
Eco+:
Energy saving and extendedlifetime in lighting solutions
High energy efficientLED lamps
Thermal conductivity,design freedom, highproductivity
Aluminum replacement,Productivity gains,energy savings andmaterial reduction
Philips Master LED lamp
DSM Engineering Plastics - Stanyl® TC
Thermally conductive plasticsWhen are they of use?Plastics are thermal insulatorswith typical conductivities
W/mK
This low value is due to:• Random orientation of polymer• chain segments• Weak coupling between polymer• chains• Vibrations only transmit efficiently• along a chain contour
DSM Engineering Plastics - Stanyl® TC
2.0polymer
Thermally conductive plasticsWhen are they of use?Measuring the thermal conductivityIf we measure the thermalconductivity of Dyneema® ropes, i.e.,Moleculary aligned UltraHighMolecular Weight Polyethylene,
W/mK [1D] is obtained.
DSM Engineering Plastics - Stanyl® TC
45polymer
Thermally conductive plasticsWhen are they of use?In metals and crystalline ceramics,vibrations can transmit efficientlyin 2D or 3D
Therefore, Metals, ceramics have TCvalues W/mK.
We rely on fillers to make TC-plastics.
DSM Engineering Plastics - Stanyl® TC
1001100
ceramic
metal
Thermally conductive plasticsWhen are they of use?The compound thermal conductivity is described fairly accurately by the Halpin-Tsai equation with Lewis-Nielsen correction [Ind.eng.chem., Fundam., 13(1) (1974),17-20]
DSM Engineering Plastics - Stanyl® TC
22max,2
max,2
12
12
2
21
11
/1/
2
11
AB
DLA
BAB
Input: plastic, filler, amount of filler, shape of the filler particles
Thermally conductive plasticsWhen are they of use?Filler particle aspect ratio L/D~15:
DSM Engineering Plastics - Stanyl® TC
Thermally conductive plasticsWhen are they of use?Improved filler with muchhigher aspect ratio:
Conclusion:best we can do in thermallyconductive plastics is
20W/mK, which is wellbelow 100W/mK formetals and ceramics.
DSM Engineering Plastics - Stanyl® TC
Thermally conductive plasticsWhen are they of use?Does this mean thatmetal replacement isnot an option?
DSM Engineering Plastics - Stanyl® TC
Heat source Convective coolingor metal contact
x=0 x=d
)(
0
airdxdx
xin
TThxT
tTqx=0:
x=d:
c pTt
2 Tx 2
inq
Thermally conductive plasticsWhen are they of use?No it doesn’t:
DSM Engineering Plastics - Stanyl® TC
Convectionlimited
Conductionlimiteddq
T in
In a convection limitedsituation, one can lower(=replace metal) withoutincreasing parttemperatures. Just look forthe right applications.
Target application: LED lamp holder
Plastics for the lamp-holder
DSM Engineering Plastics - Stanyl® TC
Not: package material.Package material needs to have highreflectivity + retention of reflectivity.
Lamp holderneeds thermalconductivity.
Target application: LED lamp holder
Why? Because LED is future in lighting
DSM Engineering Plastics - Stanyl® TC
Target application: LED lamp holder
LED enemy #1 is heat. Heat reduces LED lifetime and light output,it needs thermal management
DSM Engineering Plastics - Stanyl® TC
50
60
70
80
90
100
2 y 6 y
T junction = 63 C
T junction = 74 C
Useful life of high brightness white LED at different operating temparatures
Ligh
t out
put [
%]
Time [hours]
1000 10000 100000
Target application: LED lamp holder
Thermal management can be done in aluminum with =150 W/m*K
DSM Engineering Plastics - Stanyl® TC
TLED = 125.7°C - Tmin = 115.1°C
Target application: LED lamp holder
It can not be done with regular thermoplastics with typical =0.25 W/m*K
DSM Engineering Plastics - Stanyl® TC
TLED = 168.3°C - Tmin = 70.92°C
Target application: LED lamp holder
But it can be done in thermo-conductive plastics with intermediate TC-valuesonly. E.g., =5 W/m*K
DSM Engineering Plastics - Stanyl® TC
TLED = 130.5°C - Tmin = 113.4°C
Thermal Measurements
Proof of priciple• In order to determine the effect of different heat conductivities ( ) four different
materials are compared in the same setup.The materials are:
Alu = 160 W/m.KStanyl TC501 = 12 W/m.KStanyl NC160A = 4 W/m.KStanyl TW200F8 = 0.4 W/m.K
• All materials were sampled in plates 80 x 80 x 2 mm and mounted with a 1 W ledon a mcpcb as heat source. The temperature of the led and the temperatureof a point on the substrate at a distance 15 mm from the led were measured.
• In order to assure a good thermal contact between the mcpcb and the fourdifferent substrates a heat conductive paste was applied.
• The substrates could dissipate the heat free to the air by natural convection
DSM Engineering Plastics - Stanyl® TC
Thermal Measurements
Setup
DSM Engineering Plastics - Stanyl® TC
Stanyl® TC501= 12 W/m.K
Stanyl® TW200F8= 0.4 W/m.K
Stanyl® NC160A= 4 W/m.K
Alu= 160 W/m.K
Thermal Measurements
Example Stanyl® TC501
DSM Engineering Plastics - Stanyl® TC
LED temp TC501 plate LED TC501
Thermal Measurements
Results summary
DSM Engineering Plastics - Stanyl® TC
[ W/m/K] T led [ºC] T substrate [ºC]
Alu 160 47.5 42.3
Stanyl TC501 12 54.1 39.4
Stanyl NC160A 4 72.1 42.5
Stanyl TW200F8 0.4 95.0 41.9
Ambient temperature = 23 ºC
Thermal Measurements
Conclusion• The effect of different heat conductivities is demonstrated.• Heat conductivities in the range 4 - 15 W/m.K can be sufficient to design for
thermal management.• Heat conductivities over 20 W/m.K have no significant contribution in boosting
the heat management.
DSM Engineering Plastics - Stanyl® TC
Find out moreDSM Engineering Plastics - Stanyl® TC
For more information or an appointment for personal advice please contact:
Stijn Meijers: [email protected] Segment Manager Lighting applications