simulation of a battery electric vehicle - gtisoft.com · simulation of a battery electric vehicle...

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Institut für Verbrennungsmotoren und Kraftfahrwesen

1 20.10.2014 Markus Auer

Simulation of a Battery Electric Vehicle

M. Auer, T. Kuthada, N. Widdecke, J. Wiedemann

IVK/FKFS University of Stuttgart

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Agenda

Motivation

Thermal Management for BEV

Simulation Model

Baseline Range

Optimizations of Thermal Management System

Preconditioning of Cabin

Summary

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Motivation

Emission-free traveling

Limited range

Uncertain lifespan of battery

Smaller waste heat

HVAC of cabin

Smart thermal management

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4

Components

Electric motor

Inverter

Cabin

Battery

Requirements

Limit max. temperature of

motor and inverter

Satisfy need for cabin

comfort

Condition battery to

operating range

20.10.2014 Markus Auer

Thermal Management for BEV

[3]

[1] [2]

[4]

[1] fotos.autozeitung.de

[2] eal.jku.at

[3] gwv-fachverlage.de

[4] autogenau.de

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Simulation Model - TheFaMoS

Matlab / Simulink

Heat flow

Speed of coolant pumps

AC compressor speed

Fan and blower speed

Vehicle velocity

Ambient conditions

GT-SUITE

Temperatures

Pump power

Compressor power

Blower power

Fan power

For reliable

prediction a

simulation tool

was developed

Co-Simulation

Matlab / Simulink

and GT-SUITE

Usage of test

bench results for

calibration

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Thermal Management System

AC HP AC LP Batt. Motor

C

o

n

d

E

v

a

p

HX

P

T

C

Chiller PTC

Batt

Charger Motor

H

T

/

L

T

C

H

X

Cond

p

p

p

Inverter

Bypass HT-LT

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GT-SUITE Model

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8

dummyR

an

ge

/ k

m

25

35

45

55

65

75

85

Tamb / °C

-20 -10 0 10 20 30 40

CADC FKFS NEDC NYCC


Baseline Range

Range is determined with drive

until the battery is empty

NEDC and CADC similar

ranges

Range in FKFS cycle is slightly

lower

In very slow NYCC (Vave=11,4

km/h) the range is low due to

HVAC consumption

Trends of the range depending

on temperature are similar for

all cycles

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9

DR

an

ge

/ %

0

2

4

6

8

10

12

14

Tamb / °C

-20 -10 0 10 20 30 40

CADC FKFS NYCC NEDC

dummy


Circulating Air Quota (50%)

Speed control of the blower is

not changed

Usage of a mixer which is set

to approximately 50%

recirculating air

At -18°C and 35°C, the

benefits of recirculating air are

clearly visible

At 10°C and 25°C, the effect is

negligible

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10

DR

an

ge

/ %

-10

-8

-6

-4

-2

0

Tamb / °C

-20 -10 0 10 20 30 40

CADC FKFS NYCC NEDC

dummy


Usage of Waste Heat to Heat the Cabin

The baseline uses a cabin

heat exchanger to use waste

heat from the motor circuit

If this usage is suppressed

and the heat deficit

compensated by the PTC and

the heat pump, the range

drops significantly

If a synchronous motor is

used, the effect is smaller

since the efficiency is higher

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11

DR

an

ge

/ %

-7

-6

-5

-4

-3

-2

-1

0

Tamb / °C

-20 -10 0 10 20 30 40

CADC FKFS NYCC NEDC

dummy


Heat Pump

The baseline uses a heat

pump for the heating of the

cabin

If the heat pump is turned off

and the heat deficit is

compensated by the cabin heat

exchanger and the PTC, the

range decreases

The elimination of the heat

pump is more drastic than the

elimination of the cabin heat

exchanger

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12

DR

an

ge

/ %

1.0

1.5

2.0

2.5

3.0

3.5

Tamb / °C

-20 -10 0 10 20 30 40

CADC FKFS NYCC NEDC

dummy


Waste Heat Usage for Heating of Battery

In the baseline the PTC is

below 10°C used to keep the

battery at operating

temperature

If waste heat is used instead,

the range is increased

Range is on average

increased by about 2.5%

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13

DR

an

ge

/ %

-6

-5

-4

-3

-2

-1

0

1

Tamb / °C

-20 -10 0 10 20 30 40

CADC FKFS NYCC NEDC

dummy

The battery loses / gets a lot of heat from the environment, if

it is not insulated

If α is increased from 0 W/m²K to 10 W/m²K, the range

decreases

NEFZ

a / W

/m2K

0

5

10

15

20

25

30

35

40

45

50

Tamb / °C

-20 -10 0 10 20 30 40

1.8090.0410.6451.752

2

1.75

1.7

1.5

1.25

1

0.75

0.5

0.25

NEDC |QBatt=>Amb/QBatt|


Insulation of Battery

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14

dummy

DR

ang

e / %

0

5

10

15

20

Tamb / °C

-20 -10 0 10 20 30 40

CADC FKFS NEDC NYCC


Combination of Single Optimizations

Relative to baseline

Recirculating air 50%

Lightened motor

Adapted cabin mean

temperature with

compensation of heat deficit

Usage of waste heat to heat

the battery

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15

dummy

DR

ang

e / %

0

5

10

15

20

25

30

Tamb / °C

-20 -10 0 10 20 30 40

CADC FKFS NEDC NYCC

dummy

Ra

nge

/ k

m

30

40

50

60

70

80

90

Tamb / °C

-20 -10 0 10 20 30 40

CADC FKFS NEDC NYCC


Combination of Single Optimizations

As before, only with respect to baseline without cabin heat

exchanger and heat pump

Significant advantages can be seen at low temperatures

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16

NEDC

Co

nsu

mp

tio

n / k

Wh

4.0

4.5

5.0

5.5

6.0

6.5

TCabin,start / °C

-20 -10 0 10 20 30

with consumption for preconditioning w/o consumption for preconditioning

dummy

dummy

DC

on

sum

ptio

n / %

-15

-10

-5

0

5

Tamb / °C

-20 -10 0 10 20 30 40

CADC FKFS NYCC NEDC


Preconditioning of Cabin

Total energy consumption increases with preconditioning

With preconditioning at low temperatures, the consumption

can be significantly reduced

-18°C

ambient

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Summary

Simulation model of a battery electric vehicle

Thermal management system with AC and heat pump

Baseline range

Potential for single optimizations

Potential of combination of single optimizations

Effect of preconditioning of cabin on consumption

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Acknowledgement

The authors would like to thank

Forschungsvereinigung

Verbrennungskraftmaschinen e. V.

Gamma Technologies

Members of the working group

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Thank you for your kind

attention!

Questions?

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Backup

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21 Time [s]

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140FKFS


FKFS Lap (Stuttgart, Germany)

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NYCC

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NEDC

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CADC

simulation of a battery electric vehicle - gtisoft.com · simulation of a battery electric vehicle...

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