Ultra-thin

minichannel

LCP

for

EV

battery

thermal

management

L.W.

Jin

a

,

b

,

P.S.

Lee

a

,

⇑

,

X.X.

Kong

a

,

c

,

Y.

Fan

a

,

S.K.

Chou

a

a

Department

of

Mechanical,

National

University

of

Singapore,

21

Lower

Kent

Ridge

Road,

Singapore

119077,

Singapore

b

School

of

Human

Settlement

and

Civil

Engineering,

Xi’an

Jiaotong

University,

28

Xianning

West

Road,

Shaanxi

710049,

China

c

GCoreLab

Private

Ltd.,

21

Science

Park

Road,

Singapore

117628,

Singapore

h

i

g

h

l

i

g

h

t

s

󰀂

The

oblique

fin

maintains

boundary

layer

to

be

re-developed

periodically.

󰀂

The

injection

of

secondary

flow

accelerates

the

heat

propagation

into

fluid

core.

󰀂

The

temperatures

on

the

oblique

fin

are

lower

than

those

on

the

straight

channel.

󰀂

The

T

uniformity

on

oblique

fin

is

much

uniform

than

that

on

straight

channel.

󰀂

The

oblique

LCP

achieves

higher

heat

transfer

coefficient.

a

r

t

i

c

l

e

i

n

f

o

Article

history:

Received

28

September

2012

Received

in

revised

form

31

May

2013

Accepted

4

July

2013

Available

online

1

August

2013

Keywords:

Electric

vehicles

(EVs)

Heat

transfer

Liquid

cold

plate

Minichannel

Oblique

fin

a

b

s

t

r

a

c

t

The

development

of

electric

vehicles

(EVs)

demands

for

complementary

technologies

in

battery

thermal

management.

To

achieve

fast

charging/discharging

capacity,

liquid

cooling

is

an

effective

means

of

main-

taining

temperature

of

a

battery

in

operation

within

a

narrow

optimal

range.

In

conventional

straight

channels,

convective

heat

transfer

deteriorates

along

the

axial

direction

with

the

development

of

the

hydrodynamic

boundary

layer,

resulting

in

elevated

maximum

temperature

and

significant

temperature

gradient

in

the

fully

developed

region.

This

is

a

serious

problem

as

temperature

uniformity

is

of

utmost

importance

to

the

performance

and

lifespan

of

a

Li–ion

battery.

In

this

research,

a

simple

configuration

of

oblique

cuts

across

the

straight

fins

of

a

conventional

straight

channel

design

was

developed,

to

enhance

the

performance

of

the

conventional

channel

with

minimal

pressure

penalty.

These

oblique

cuts

across

the

straight

fins

form

an

oblique

fin

array.

The

designed

liquid

cold

plate

(LCP)

contains

these

simple

obli-

que

fins

with

optimized

angle

and

width.

This

segmentation

of

the

continuous

fin

into

oblique

sections

leads

to

the

re-initialization

of

boundary

layers,

providing

a

solution

to

the

elevated

temperatures

caused

by

a

thick

boundary

layer

in

the

fully

developed

region.

Experimental

results

show

that

heat

transfer

coefficients

of

oblique

minichannel

are

higher

than

those

of

conventional

straight

minichannel.

The

obli-

que

LCP

is

able

to

maintain

the

battery

surface

average

temperature

below

50

°

C

for

a

heat

load

of

1240

W

at

a

flow

rate

lower

than

0.9

l/min.

This

implies

that

a

proper

designed

minichannel

cold

plate

could

be

a

promising

solution

for

EV

battery

thermal

management.

Ó

2013

Elsevier

Ltd.

All

rights

reserved.

1.

Introduction

The

global

demand

for

vehicles

is

experiencing

rapid

growth,

especially

in

developing

countries.

On

the

contrary,

the

use

of

con-

ventional

non-renewable

resources

such

as

petroleum

and

natural

gas

are

being

limited

due

to

carbon

emissions

quota

and

worries

of

the

depleting

supply.

Environmental

problems

concerning

air

pol-

lution

and

greenhouse

gas

emissions

are

intensifying

and

have

turned

into

global

challenges.

Therefore,

the

development

of

elec-

tric

vehicles

(EVs)

and

hybrid

electric

vehicles

(HEVs)

has

been

rec-

ognized

as

an

effective

solution

towards

global

sustainable

development

[1]

.

The

current

EV/HEV

power

source

of

choice,

Li–ion

batteries

have

chemical

processes

that

are

largely

exothermic.

Heat

gener-

ated

has

to

be

managed

well

in

order

to

prevent

battery

degrada-

tion

due

to

temperature

rise.

Waag

et

al.

[2]

investigated

the

impedance

characteristics

of

Li–ion

battery

in

terms

of

the

battery

state-of-charge,

temperature

and

current,

etc.

It

was

found

that

the

battery

resistance

was

affected

considerably

by

the

change

of

tem-

perature.

The

research

of

thermal

runaway

potential

of

Li–ion

bat-

tery

conducted

by

Jhu

et

al.

[3]

indicated

that

the

explosion

could

be

caused

by

the

violent

thermal

decomposition

in

a

runaway

0306-2619/$

-

see

front

matter

Ó

2013

Elsevier

Ltd.

All

rights

reserved.

http://dx.doi.org/10.1016/j.apenergy.2013.07.013

⇑

Corresponding

author

at:

Department

of

Mechanical,

National

University

of

Singapore,

21

Lower

Kent

Ridge

Road,

Singapore

119077,

Singapore.

Tel.:

+65

65164187.

E-mail

addresses:

lwjin@mail.xjtu.edu.cn

(L.W.

Jin),

mpelps@nus.edu.sg

(P.S.

Lee).

Applied

Energy

113

(2014)

1786–1794

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