EVS28 KINTEX, Korea, May 3-6, 2015

Development of hydrogen storage tank

used for Fuel Cell Electric Vehicle

(FCEV) by numerical analysis

Dongsun Lee1, Jaehan Jung2, Jungik Kim2, Chulho Im2 1, 2Fuel cell vehicle team, HYUNDAI MOTOR GROUP, 17-5, Mabuk-ro #240,yongin-si,

kyeonggi-do, 446-716, Korea, dongsun2@hyundai.com

Contents

I. Introduction -Background and objectives of study

II. Research procedures

III. Development of engineering design technique - Development of FE modeling tool on winding patterning

- Development of estimating method on the boss thickness of composite

- The manner of optimizing on the filament winding pattern

IV. Results and Discussions - The estimation of boss thickness after filament winding

- Burst test

- Main expected effect of optimized model

2

I. Introduction Background and objective

What is the core technology on FCEV and

the method of weight reduction?

3

Item World 1st mass produced

Fuel Cell Vehicle (’13/2)

Gas mileage 415 km

Weight percent 4.4 wt%

Price 77,000$

※ 1,100 KRW/1$

Cost down and weight reduction by optimization on the laminate design of

carbon fiber which is about 85% of CFRP

- %

18%- %

- %

- %

- %

- %- %

0

Portion of the price on component Component of hydrogen tank

Liner

: Gas seals and withstanding winding force of carbon fiber

CFRP : Withstanding high pressure of hydrogen

Plastic

Aluminum Hydrogen storage system

--------------------

--------------------

--------------------

--------------------

--------------------

--------------------

--------------------

4

Design optimization of winding pattern by development both structural

modeling and analysis technique on hydrogen tank

Development of optimization technique

Production and evaluation

Designing of winding pattern by

Reverse Engineering

Product development by trial and error

Production Evaluation Design

Need for

designing

/ analysis

technique

Development of modeling technique - Improving pilot program (W/SIMULIA South)

- Standard satisfaction (2.5times of charging pressure)

Proposition of equation on the revised design

regarding real shape FE modeling of winding

angle and thickness of

CFRP

Estimating boss

thickness by

proposed equation

Design/analysis of winding pattern Evaluation of optimal pattern Burst test Comparison analysis/experiment

b

c Max strainregion

2nd strainregion

1.524 %

1.490 %

Fracture at cylinder

a

Burst pressure:

1,729bar

(Predict value)

1,798bar

c

b

II. Research procedures Approach

5

III. Development of engineering design technique Development of FE modeling tool on winding patterning

Dome

Cylinder

Symmetry condition

Tie condition (Al6061 & DPE)

Contact condition (liner & composite)

Improving pilot program

defining material properties

(w/SIMULIA South)

Characteristics

- Generation of material

property with winding

angle

- Defining composite

thickness with variable

dome curvature

- Calculation of strain and

stress in the fiber direction

1

2

3

1

2

3

Development of modeling technique on the variable winding angle

and thickness with variable dome curvature

■ The method of Classical equation estimating composite

thickness Estimation of composite thickness near boss

→ It is hard to estimate the composite thickness

near boss (The angle is 90 degree)

Fig.1 Illustration of H2 tank model Magnification of “1” in Fig.1

n

tl

rrr

rr

r

rr

0

001sin)(

4

2)cos(

)cos(

rr

rrBWr

rtt

tl

tl

tl

r

tltlr

ttl = Thickness at tangential line

Θtl = Angle at tangential line, Θr= Winding angle

rtl = Radious at at tangential line in dome

r0= Radious at helical end tip

BW= Bandwidth

1

Fig.2 Fig.1의 1”구역 확대 그림

composite

Thickness of boss Thickness

of composite

Dome

part

Cylinder

part

Aluminum

Liner

Composite

Plastic

Liner

1 -------- Eq.6

-------- Eq.7

6

III. Development of engineering design technique Development of estimating method on the boss thickness of composite

Proposition of equation that is able to estimate

the thickness of composite near boss

■ The method of Classical equation estimating composite thickness

Estimation of composite thickness near boss

→ It is hard to estimate the composite thickness

near boss (The angle is 90 degree)

Fig.1 Illustration of H2 tank model Magnification of “1” in Fig.1

n

tl

rrr

rr

r

rr

0

001sin)(

4

2)cos(

)cos(

rr

rrBWr

rtt

tl

tl

tl

r

tltlr

ttl = Thickness at tangential line

Θtl = Angle at tangential line, Θr= Winding angle

rtl = Radious at at tangential line in dome

r0= Radious at helical end tip

BW= Bandwidth

1

Fig.2 Fig.1의 1”구역 확대 그림

composite

Thickness of boss Thickness

of composite

Dome

part

Cylinder

part

Aluminum

Liner

Composite

Plastic

Liner

1-------- Eq.6

-------- Eq.7

7

III. Development of engineering design technique Development of estimating method on the boss thickness of composite

Proposition of equation that is able to estimate

the thickness of composite near boss

Illustration of overlapping composite layer near boss

* 6 overlapping region of composite layer

Outside diameter

of boss

Composite band

)))/)/((360/(90 BWrN lp

hphboss NNtt 2))1/((

■ Numenclature

tboss = The thickness of boss

ηα = Rduction rate of band width

th = Initial thickness of helical layer

Np α = A number of overlapping on helical band

at winding angle α

Nh α = A number of helical layer with winding angle α

rl = Full diameter of plastic liner

rb = Full diameter of aluminum boss

BW = Bandwhidth

bb rrBW 2)(if , 1 pp NN

bb rrBW 2)(if , pp NN

-------- Eq.8

-------- Eq.9

■ The equation of estimating thickness on composite

8

III. Development of engineering design technique The manner of optimizing on the filament winding pattern

The estimation of optimal winding pattern by stress/strain

trend line and burst limit condition

0

1000

2000

3000

4000

0 15 30 45 60 75 90

Ma

x. P

rin

c. S

tres

s [

MP

a]

Winding angle [˚]

Inside tube helical

Outside in Transition region

Inside in transition region

Inside hoop

2322 2326 2330

1000

1500

2000

2500

0 1 2 3 4 5 6 7 8 9 10

Fib

er d

irec

tio

na

l S

tres

s [

MP

a]

Number of helical layers [EA]

1st_hoop

2nd_hoop

3rd_hoop

1st_tube helical

2nd_tube helical

3rd_tube helical

Helical_23D

Helical_12D

Helical_10D

■ Stress variation with winding angle ■ Stress variation with thickness of composite layers

- Investigation of minimum stress

condition with winding angle

- Investigation of minimum stress

condition with thickness of composite layers

- Investigation on the hoop stress with variable

helical thickness

9

IV. Results and Discussions Production of hydrogen storage tank

Production of hydrogen storage tank by filament winding method

Carriage

b

Composite

Liner (Al6061)

Liner (HDPE)

c

Rotation

Moving direction of carriage

Liner Motor

a,b: Winding appratus c: Aluminum/HDPE liner

Resin Bath

a

■ Winding condition

- Tension of fiber: 9.8~14.7 N

- Motor rpm: 60 rpm

- Carriage speed: 500mm/sec

■ Curing condition

- 60 ℃ (2hr) → 85℃ (2hr)

→ air-cooling (10hr) Hoop

Helical

Composite

Liner(Al6061)Liner

(HDPE)

10

IV. Results and Discussions The estimation of boss thickness after filament winding

#2 #3 #4

Tank

No.

Estimating

thickness [mm]

Producing

Thickness [mm]

Error

[%]

Pass/

fail

#1 46.0 58.0↑ 26.0↑ Fail

#2 54.8 57.0 4.0 Pass

#3 54.8 56.0 2.2 Pass

#4 54.0 56.0 3.7 Pass

1

Fig.2 Fig.1의 1”구역 확대 그림

composite

Thickness of boss Thickness

of composite

With equation

Without equation

■ The results of evaluation on the estimated equation

Production of the hydrogen tank and estimation the thickness of composite near boss within 4% error

11

IV. Results and Discussions Burst test

b

c

Burst pressure:

1,755bar

(Predict value)

Max strainregion

2nd strainregion

1.524 %

1.434 %

c

b

Fracture at cylinder

a

1,792bar

The result of burst test of sample #3 The result of burst test of sample #4

b

Burst pressure:

1,729bar

(Predict value)

Burst pressure:

1,755bar

(Predict value)

C

b

c Max strainregion

2nd strainregion

1.524 %

1.490 %

Fracture at cylinder

a

Burst pressure:

1,729bar

(Predict value)

1,798bar

c

b

b

c Max strainregion

2nd strainregion

1.524 %

1.490 %

Fracture at cylinder

a

Burst pressure:

1,729bar

(Predict value)

1,798bar

c

b

b b

c

Burst pressure:

1,755bar

(Predict value)

Max strainregion

2nd strainregion

1.524 %

1.434 %

c

b

Fracture at cylinder

a

1,792bar

C

Test sample #3: Error 3.9% (Anal.: 1,729 bar, Exp.: 1,798 bar)

Test sample #4: Error 2.1% (Anal.: 1,755 bar, Exp.: 1,792 bar)

12

IV. Results and Discussions Main expected effect of optimized model

The effect of optimal hydrogen tank model

→ weight of carbon fiber 8.5% ↓/ weight efficiency of H2 13.6%↑

Tank sample The weight of

hydrogen tank

The weight of

carbon fiber

Weight efficiency

of hydrogen

Commercial

product 90.0 kg (standard) 52.0 kg (standard) 4.4 wt% (standard)

Optimal

sample 82.5 kg (8.3%↓) 47.6 kg (8.5%↓) 5.0 wt% (13.6%↑)

Conclusion

13

1 Development of modeling technique on hydrogen storage tank

☞ The reliability between analysis and experiment was approximately 3%

2 Proposition of equation on the revised design regarding real shape

☞ Estimating error on the composite thickness near boss 4% was approximately 4%

3 Effect of the optimal design on the weight reduction and efficiency

☞ Weight efficiency of hydrogen 13.6% ↑, The weight of carbon fiber 8.5% ↓