Dear Expert,

The 5th Thermal Management for EV/HEV Conference 2016 aims to explore

practical solutions for optimal cooling and heating as an integrated part of vehicle

development.

Our conference will bring together experts from along the value chain to ensure

maximum knowledge transfer, professional exchange and networking

opportunities. For more information and the schedule of events, please download

the agenda, email at eq@iqpc.de or call +49 (0) 30 20 913 - 274

We look forward to meeting you in February 2016 in Berlin!

Today we are pleased to share with you a presentation by one of our speakers from

our previous Conference.

Dr. Sascha Populoh, materials and Energy Conversion at Empa - Swiss Federal

Laboratories for Materials Science and Technology:

Kind regards,

Automotive IQ / A Division of

Waste heat recovery by thermoelectricity 

Sascha Populoh 

Thermal Management for EV/HEV

Empa, Swiss Federal Laboratories for Materials Research and Technology

Outline

• Introduction to thermoelectricity

• Materials and module development based on

Half Heusler compounds

The thermopower:classical definition of S

Thermoelectric modules

load Ra

p p p pn n n n

cold

hotElectr. current

n p n p

RL

e- +e-

e- e-

e-

e-e- e-

e-e-

e- e-+ +e- e-+ +

V = S ΔT

Thermoelectric power generation

Advantages of thermoelectricpower generation

o heat engine without moving partso no mechanical or chemical processes involved silent, emission free, no vibrations  robust and durable, nearly no

maintenance, high reliability (> 250’000 h) o flexible: power from W to MW and from

T < 1 K to T > 1000 K

A thermoelectric generator is a unique heat engine  in which “mobile charge carriers serve as working fluid”. 

T≈37°C skin

T>1000°C solar

Voyager 1 & 2 

start 1977

3 RTGs à 158 W

Automotive applications

P. Soltic et al., Empa

About83% (inefficient old gasoline passenger car) to55% (heavy duty diesel truck)

of the fuel energy is convertedinto heat

Outline

• Introduction to thermoelectricity

• Materials and module development based on

Half Heusler compounds

Materials development:    n‐type Half Heusler (XYZ)

High ǀSǀ (300 µV/K)Low ρ (10‐4 Ωm) 

High κ (10 W/Km)

Populoh et al. Scripta Mater (2012), 66 (12), 1073. 

Isoelectronic substitution on the X‐position: Ti0.37Zr0.37Hf0.26NiSn

HH p‐type: Ti(CoFe)Sb withInSb nanoinclusions

InSbBoundary ScatteringElectron Filtering Effect

↓

↑  without decreasing Electron injection Effect ↑

1.0 at.% InSb NI: ~ 450% increase of ZT

Xie et al. Acta Mater (2013), 61 (6), 2087. 

Assembly of HH‐module

Characterisation

300 400 500 600 700 800 9000.0

0.1

0.2

0.3

0.4

0.5

0.64

5

6

7

2E-5

4E-5

6E-58E-51E-4

ZT

Temperature (K)

(c)

Th. c

ondu

ctiv

ity (W

/Km

)El

. res

istiv

ity (

m)

-300

-270

-240

-210

-180

-150

(b) Seeb

eck

coef

ficie

nt (

V/K)

(a)

Populoh et al. Materials (2013), 6 (4), 1326. 

Comparison with other modules

Module Material T (K)Max power output 

(mW)Leg dimensions 

(mm)Power densitity (mW/cm3)

HH‐Empa TiZrHfNiSn 565 44 4 times 2*2*4 700Heusler

Mikamichi Fe2VAl 300 940 36 times 5*5*5 280

Oxide Empa CaMnO3 622 88 4 times 4*4*5 275

Oxide Funahashi Ca3Co4O9 500 94 4 times 3.7*4.5*4.7 660

Assembly of a module comprising high ZT materials isunderway

Summary

• Thermoelectricity is a highly reliable possibility to convert waste heat to electricity

• Max. Power T‐Hex: @ Tcold40°C= 120 W, @Tcold80°C= 78 W

• Thermoelectric HH compounds with a high conversion efficiency

• First unileg Test module based HH compounds

Outlook

• Redesign of 2nd generation T‐Hex                    for higher energy extraction,                              and later catalytic covering of fins

• Materials research: Combination of substitution and nano‐inclusion approach for new high ZT compounds

• Module development: use of materials with ZT ≈ 1, contact material investigation

That’s all folks!

Thanks for your attention

Supplementary

TEG TEP1‐1265‐0.8

*nmat 2090 / Complex thermoelectric materials / G. Jeffrey Snyder* and Eric S. TobererMaterials Science, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA

Spezification of the Module TEP1‐1265‐0.8

Hot side temperatur (°C) 330

Cold side temperatur (°C) 30

Open circuit voltage (V) 9.9

Matched load resistance (ohms) 1.67

Matched load output current (A) 2.9

Matched load output power (W) 14.5

Heat flow across the module (W) ~ 302

Heat flow density (W cm‐2) ~ 9.6

AC resistance (ohms) measuredunder 27 °C at 1000 Hz

0.7 ~ 1.0

Temperature field from 80‐350°C

* * *

N / P type of Module BiTe based material

…Join the 5th International Conference Thermal Management for

EV/HEV in Germany, February 16-18.

This forum will bring speakers from the automotive industry as

well as top Battery experts from around the world:

Explore practical solutions for optimal cooling and heating thermal systems for EV

and HEVs

Advance powertrain architecture for optimum thermal distribution

Identify hardware hazards and eliminate risks from systems concept phase

Manage thermal management as an integrated part of vehicle development

Find solutions for optimized passenger comfort and energy efficiency of cabin

climate control systems