State of the Art of Batteries of the 4 Generation 2015 Wagner final.pdf · State of the Art of Batteries of the 4th Generation N. Wagner, N.A. Cañas, D. Wittmaier and K.A. Friedrich

State of the Art of Batteries of the 4th

Generation

N. Wagner, N.A. Cañas, D. Wittmaier and K.A. FriedrichGerman Aerospace Center, Institute for Engineering

Thermodynamics, Pfaffenwaldring 38-40, 70569 Stuttgart, Germany

8th International Workshop on Impedance Spectroscopy (IWIS)23-25 September, Chemnitz, Germany

Presentation outline

• Introduction and motivation• Definition 4th generation batteries• Examples of batteries and applications

• Metal-Sulfur Batteries• Li-Sulfur and Mg-Sulfur Batteries• Production technique• Characterization

• Metal-Air Batteries• Li-Air and Zn-Air Batteries• Production techniques at the DLR• Characterization

• Outlook

8th IWIS 2015, Norbert Wagner

Novel Battery Concepts – Specific Energy Potentials

Li-Ionhigh E

Pb Li-Ionhigh P

Li/S Li-air

10 100 1000 10000

gasoline(50 % of theoretical max.)

10 100 1 000 10 000Specific Energy / Wh/kg

Y. Mikhaylik et al., Sion Power Corp., ECS presentation, 2009.

USABC targetsLi/S (2009)

Rate Cap.

Lower T

Power Density

Specific Power

Recharge Time

Specific Energy

Energy density

Upper T

Cycle life

Chemistry Cell size Wh/L *theory

Wh/L actual

% achieved

Wh/kg *theory

Wh/kg actual

% achieved

LiFePO4 54208 1980 292 14.8 587 156 26.6LiFePO4 16650 1980 223 11.3 587 113 19.3LiMn2O4 26700 2060 296 14.4 500 109 21.8LiCoO2 18650 2950 570 19.3 1000 250 25

Si-LiMO2Panasonic 18650 2950 919 31.2 1000 252 25.2


700

600

500

400

300

200

100

0

Spe

cific

Ene

rgy

@ c

ell l

evel

/ W

h kg

-1

203520302025202020152010

Year

150‐175 Wh/kg

175‐240 Wh/kg

> 350 Wh/kg

New SystemsLi‐S, Li‐Air andothers?

Limit of Li‐Ion Technology

Technical Progress: Improvement of Energy Density

Limit ?

Improvement jump

Lithium‐IonAdvanced activematerials

Lithium‐IonImproving existingChemistries


Electrochemical pairs of Li-ion, post-Li ion and post-Li systems

Gravimetric energy density (Wh/kg)

Li-ion

Ca/CoF3

Chlorides

Mg/CuCl2

Ca/CuCl2

Li/CuCl2

Fluorides

La/CoF3

Ca/CoF3

Li/FeF3

Li/CuF2

LiC6 / NMC

Volu

met

ricen

ergy

dens

ity(W

h/l)

Mg batteries

MetalSulphur

Li/S

Mg/S

Metal-Air

Li/O2

Mg/O2

Zn/O2Na/O2

Na-ion

Hard-C / NaNMC

Li rich fcc materials

Li2VO2F

Li2CrO2F

Electropositive Electronegative

Chemistry of Fuel Cells and Batteries

2H2 + O2 2H2O

Hea

vy

Lig

ht




2H2 + O2 2H2O2Li + O2 Li2O (Li2O2), LiOH

Hea

vy

Lig

ht




2H2 + O2 2H2O2Li + O2 Li2O (Li2O2), LiOH16Li + S8 8Li2S8Mg + S8 8MgS

Hea

vy

Lig

ht


Production and Characterisationof cathodes forLithium-Sulfur andLithium-air batteries

Characterisation ofLi-ion batteries within-situ and ex-situ-methods

Activities of the „Batterietechnik“ team at DLR

Source: N AT U R E | VO L 5 0 7 | 6 M A R C H 2 0 1 4


Metal-Sulfur Batteries


Metal-Sulfur Batteries: Overview

Electrochemical Reaction ΔG Voltage Capacity(Cathode)

Energy density

kJ/mol V mAh/g Wh/kg Wh/L

Mg + S ↔ MgS -341.8 1.771 1672 1684 3221

2Li + S ↔ Li2S -439.0 2.275 1672 2654 2856

2Na + 3S ↔ Na2S3 -405.2 2.100 558.4 791.7 1179

2Al + 3S ↔ Al2S3 -213.3 1.106 1672 1184 2676

Zn + S ↔ ZnS -201.3 1.043 1672 573.6 2162

CoO2 + LiC6 ↔ LiCoO2 + C6 -347.4 3.600 273.8 567.8 1901


Metal-Sulfur Batterie- Summary

Electrochemical Reaction ΔG Voltage Capacity(Cathode)

Energy density

kJ/mol V mAh/g Wh/kg Wh/L

Mg + S ↔ MgS -341.8 1.771 1672 1684 3221

2Li + S ↔ Li2S -439.0 2.275 1672 2654 2856

2Na + 3S ↔ Na2S3 -405.2 2.100 558.4 791.7 1179

2Al + 3S ↔ Al2S3 -213.3 1.106 1672 1184 2676

Zn + S ↔ ZnS -201.3 1.043 1672 573.6 2162

CoO2 + LiC6 ↔ LiCoO2 + C6 -347.4 3.600 273.8 567.8 1901


‐Formation of Lithium‐Sulfur Battery: Electrochemistrydes in lithium‐sulfur batteries

Polysulfides (Li2Sx) areintermediates in the transition

of S8 to S2-

- gradual dissolution ofsulfur form the cathode

- Self-discharge- Different voltage

plateaus

Y.-S. Su et al., Nature (2013)

Electrolyte: LiPF6 in TEGDME

Cathode production technique at DLR-TT

• Nozzle with extern mixing of air andsuspension

• Cathode mixture: Sulfur or Sulfur/Carbon composite, Carbon Black and PVDF (50:40:10, wt.%). Solvents: Ethanol and DMSO

Suspension–spray machine

Sprayedcathode

5 x 5 cm2

Wet powder spraying for electrode fabrication

1

2

3

Cathode composition50 wt.% Sulfur40 wt.% Carbon Black10 wt.% PVDF

Mixing/Milling

Mixing

Solvent +PVDF

Dissolver

S + CB

Suspension

Wet‐powderspraying Drying

Air‐atomizing external mixing nozzlecontrolled by a 3D axis robot

The axis with the nozzle moves in perpendicular direction (y) to thesubstrate holder

3 times



Mixing/Milling Coating Drying

Initial procedure (Cathode I)

Roll mixer‡ Suspension spray In vacuum oven

1) Mix of S, CB and PVDF

(5 rpm, t= 12 h)

2) Mix with solvents†

(5 rpm, t= 12 h)

− Internal mixing nozzle − Coating in one step − Heating plate under

substrate (100 °C)

80 °C (48 h)

New procedure (Cathode II)

Tumbling mixer‡ Suspension spray In vacuum oven

1) Mix of S and CB

(20 rpm, t= 24 h)

2) Dissolution of PVDF in

solvents† (magnet stirring)

3) Mix of S and CB with

dissolution (2)

(20 rpm, t = 24 h)

− External mixing nozzle − Coating in 3 steps or more − No heating plate − Drying between each

sprayed layer

Between sprayed layers,

60 °C (1.5-3 h)

At the end of coating:

60 °C (24 h)

In vacuum in the glove

box

†Solvents: Ethanol/DMSO (50:50 wt.%). ‡In both cases ceramic balls were added in the

mixing tank.

N.A. Cañas, A.L.P. Baltazar, M.A.P. Morais, T.O. Freitag, N. Wagner, K.A. Friedrich, Electrochim. Acta, 157 (2015) 351-358

Influence of cathode fabrication

Influence of cathode fabrication

0.2 C

Optimization of suspension spraying and mixing processes

• Improved dispersion of S particles

• Reduction of S particle size

Cathode I Cathode II

Electrolyte: 1M LiPF6 in TEGDME

0.2 C rate


Influence of LiNO3 as co‐salt

N. A. Cañas, A. L.P. Baltazar, M.A.P. Morais, T.O. Freitag, N. Wagner, K.A. Friedrich. Electrochimica Acta 157 (2015) 351‐358

Capacity fading and coulombic efficiency is affected by the concentration of the co‐salt

Considering both the capacity fading and the Coloumbic efficiency: the optimal concentration of LiNO3 was found to be 0.75M for this cell configuration/components

Electrolyte= 1M LiPF6 in TEGDME

~100% Coulombic efficiency


Main in situ and ex situ characterization techniques

0 250 500 750 1000 1250 15000

250

500

750

1000

1250

1500

0 20 40 60 800

20

40

R0 R1//CPE1

R4//CPE4

R3//CPE3

Experimental Fitted

-Z'' /

Ohm

Z' / Ohm

R2//CPE2

60 mHz325 mHz

18 Hz

9 KHz


20

Objective:• Monitoring of crystalline reaction products of the

cathode• identification of structural changes during cycling

In situ X-Ray diffraction

X-ray radiant tube

VÅNTECdetector

PotentiostatCycling program(Thales)

In-situ cell

1) anode plate2) polymer gasket3) insulator plastic tube4) spring5) stainless steel anode collector6) anode7) separator8) cathode9) cathode plate10) Al-window 11) holes for connecting the banana jacks

N. A. Cañas, S. Wolf, N. Wagner, K. A. Friedrich. J. of Power Sources, 226 (2013) 313‐319.


21

Spectra collected during discharge

In situ X-Ray diffraction

0 20 40 60 80 100

1.6

2.0

2.4

2.8

20 22 24 26 28 30 32 34 36

0

100

200

300

400

100

80

60

40

20Polys

ulfid

es

- c -- b -- a -

Inte

nsity

/ a.

u

- c -

- b -

- a -

2-theta / °

DOD

/ %

111 (Li2S) 200 (Li2S)

222 (S8)

Vol

tage

/ V

DOD / %

0 10 20 30 40 50 60 70 80 90 1000.0

0.1

0.2

0.3

0.4111 - Li2S

Inte

g. in

tens

ity /

a.u.

Depth of discharge / %

222 - S8

(a)

(b)

0 10 20 30 40 50 60 70 80 90 100

500

750

1000

1250

1500

Am

orph

ous

area

/ a.

u


1st discharge

a) Dissolution of sulfur and reduction to soluble polysulfidesb) Soluble polysulfidesc) Li2S formation

N. A. Cañas, S. Wolf, N. Wagner, K. A. Friedrich. J. of Power Sources, 226 (2013) 313‐319.

Quantification of crystalline and amorphous phase


UV‐vis spectroscopy

References:a) Stoichiometric mixture of Li2S and S8 in TEGDME* b) Li2S in TEGDMEc) S8 in TEGDME

Experimental set‐up

Wavelength /nm

Species (in TEGDME)

245,255, 282 S− (Li2S)

243, 265, 289 cyclo S8

332 S62−

425 S42−

615 S3•−

N. A. Cañas, D. N. Fronczek, N. Wagner, A. Latz, K. A. Friedrich. J. Phys. Chem. C, 2014, 118, 12106–12114.

*TEGDME:Tetraethylene glycol dimethyl ether

Investigation and quantification of reaction intermediates (polysulfides)


Electrochemical Impedance spectroscopy (EIS)

Investigation of physical and chemical processes during cycling

0 250 500 750 1000 1250 15000

250

500

750

1000

1250

1500

0 20 40 60 800

20

40

R0 R1//CPE1

R4//CPE4

R3//CPE3

Experimental Fitted

-Z''

/ Ohm

Z' / Ohm

R2//CPE2

60 mHz325 mHz

18 Hz

9 KHz

Assignment of processes to the elements of the EC

Model Chemical and physical cause

R0 Ohmic resistance

R1-CPE1 Anode charge transfer

R2-CPE2 Cathode process: charge transfer of sulfur intermediates

R3-CPE3 Cathode process: reaction and formation of S8 and Li2S

R4-CPE4 Diffusion

N. A. Cañas, K. Hirose, B. Pascucci, N. Wagner K. A. Friedrich, R. Hiesgen, Electrochim. Acta, 2013, 97, 42–51.


ElS during 1st discharging cycle

0 20 40 60 80 1000

500

1000

1500

2000

2500

3000

200004000060000

R3

R4

R3,

R4 /

Ohm


??

0

20

40

60

80

100 R0

R1

R0,

R1 /

Ohm

0

250

500

750

1000

1250

1500

1750

2000

R2 /

Ohm

(a)

(b)

(c)

0 20 40 60 80 1001.0

1.5

2.0

2.5

3.0

Pot

entia

l / V


Discharge curve EIS measurements

0 250 500 750 1000 1250 15000

250

500

750

1000

1250

1500

0 25 50 750

25

50 DOD / % 0 27 34 62 81100

-Z'' /

Ohm

Z' / Ohm

-Z'' /

Ohm

Z' / Ohm

R0: Increase of resistance due to dissolution of Li2SxR1: Anodic charage transfer resistance influenced by Li2SxR2: Cathodic charge transfer resistance diminishes with order or polysulfide

R3: Proportional to formation of isolating products (Li2S and S8)

R4: Diffusion hindered by formation of Li2S and S8


Variation of the equivalent circuit elements during first charging determined by EIS analysis


Strong discharge

capacity fading

Decrease of cathodic charge

transfer (R2)

No complete conversion to Li2S

ElS during 50 charging/ discharging cycle

New batteries concepts Further cathode improvements

Components

• Electrolyte/sulfur weight ratio: ≤ 3/1

• Mass loading higher than 2 mg cm−2

• Sulfur utilization ≥ 70 %

Different approaches or combination of them:

• Additives: hydrophilic inorganic additives (like MexOy) for adsorption of polysulfides

• Protective layers: ion conductive interlayers for retention of active material

• Binders: replacement of conventional PVDF by ion /electric conductive additive

Guideline for an optimized electrode and cell design:

• Modeling from a single active particle to full battery cells

• Mechanistic studies of degradation processes on both electrodes


Main companies developing Li/S Batteries in industry

Oxis Energy:• 300 Wh/kg achieved at cell level in 2014• 400 Wh/kg forecast in 2016

http://www.oxisenergy.com/technology/http://www.sionpower.com/http://www.polyplus.com/

Sion Power:• 250 Wh/kg and over 300 full depth of discharge cycles (now)• 600 Wh/kg are in the foreseeable future

Berkeley, USA Tucson, USA Abingdon, UK

Target for commercialization: ca. 500 Wh/kg


Mg2+

e-

e-

Anode Cathode

discharge

charge

Mg

Good handling and operational safety

No dendrite formation using Mg metal as anode

Naturally abundant low raw material cost (currently Li/25)

Mg/S offers theoretical 4000 Wh/L while the gravimetric capacity is similar to that of LiC6

Sulfur cathode needs non-nucleophilic electrolyte

Li MgAtomic weight 6.9 24.3

Ionic radius 90 pm 86 pm

Ionic charge + 1 + 2

Reduction potential - 3.04 V - 2.37 V

Density 0.53 g/cm3 1.74 g/cm3

Gravimetric capacity 3861 mAh/g 2205 mAh/g

Volumetric capacity 2061 mAh/cm3 3832 mAh/cm3

Li-Sulfur vs. Mg-Sulfur Battery

smaller S22-

would not dissolve !

Approach to eliminate formation of soluble polysulphides

Ultramicroporous carbonmade from coconut shells (inexpensive, scalable).Pore ø 0.6 nm

S8 and soluble S82-

do not fit in pore

Hypothesis:direct transition of S to Li2S2 and Li2S

one reaction step one plateau

50 mass% S loading

e-

e-

Li+No access toelectrolyte

Reduction of polysulfide shuttle

Coconut shell

Poro

us c

arbo

n

Carbon-Sulphurcomposite

Coconut Shell derived CarbonCoconut Shell derived Carbon-Sulphur composite

CSCCSC-S

Synthesis of Coconut Shell derived Carbon-Sulphur (CSC-S) composite

Li W., Yang K., Peng, J. Zhang, Guo, S., Xia, H. Ind. Crop. Prod. 28, 190–198 (2008).

Production of Carbon‐Sulfur Composite 8th IWIS 2015, Norbert Wagner

Metal-air batteries


MotivationWhy Li-air batteries?• Highest theoretical specific energy density (11.425 Wh/kg)

Cathodic reactant, O2 from air, does not have to be stored• Environmental friendliness• Higher safety than Li-ion batteries

(only one of the reactants contained in the battery)• Potentially longer cycle and shelf lives


Motivation

G. Girishkumar et al., J. Phys. Chem. Lett.,2010, 1, 2193‐2203

Why Li-air batteries?• Highest theoretical specific energy density (11.425 Wh/kg).

Cathodic reactant, O2 from air, does not have to be stored• Environmental friendliness• Higher safety than Li-ion batteries

(only one of the reactants contained in the battery)• Potentially longer cycle and shelf lives


Li‐air battery:Functional scheme

MetallicLithium

Separator

GasDiffusionElectrode

O2

Electrolyte

LiOH

LiOH

=Lithium‐IonLi+=OxygenO2=Electron e‐=Hydroxide‐IonOH‐

Structure:• Anode,Lithiummetal (foil)• Cathode (Gasdiffusion electrode =GDE)• Separator

Reactions and products:• During discharge:OxygenReduction Reaction

(ORR)• During charging:OxygenEvolutionReaction (OER)• Reaction product:

• organic electrolyte:Li2O,Li2O2• alkaline electrolyte:LiOH

DLR:• Bifunctional Cathode (GDE)with alkaline

electrolyte (LiOH)• Globalreaction:4Li+O2 +2H2O↔4LiOH;

E=3.45V

IWIS 2015, Norbert Wagner

Architectures of Li-air Batteries

2Li+ + O2 + 2e‐ Li2O2 Erev= 2,959 V2Li++2e‐ + (1/2) O2 Li2O Erev= 2,913 V

4Li + O2 + 2H2O 4LiOH (alkaline media) Erev= 3,446 V4Li + O2 + 4H+ 2H2O + 4Li+(acidic media) Erev= 4,274 V

Non-aqueous electrolyte: Aqueous electrolyte:


Bi-functional Oxygen-Electrodes: Design

• Bi-functional Oxygen-Electrodes = catalizes ORR and OER

• Depending on manufactoring process every electrode consists of:

• Catalyst(s)• Conductive agent (C, Graphit…)• Binder (PTFE, PVdF…)• Substrate (Metal mesh,…)

Function BOE

Catalyst

Active Surface

Cond. agent

Electrolyte

Pore-structure

Design

• Different manufactoring processes used at DLR: Dry Powder Spraying, Reactive Rolling an Mixing, Pressing and APS

Manufactoring of bifunctional gas diffusion electrodes

Electrodes with noble metal and other catalysts can be made with dry power spraying technique

Oxide catalysts (La0.6Ca0.4CoO3…) can be sprayed on for example a

Rhodius substrate with APS

Rhodius substrate

Catalyst layer

Catalyst layer = catalyst+carbon/grap

hite+binder

Graphite GDE substrate

or by pressing the catalyst layer on for example a Sigracet® GDL 35 DC with a hydraulic press

Catalyst layer = catalyst+carbon/grap

hite+binder

Sigracet® GDL35 DC


Screening of bifunctional catalystsExperimental

• Thin catalyst layers reduce the influence of the electrode structure

• Cyclic Voltammetrie was carried out at a half cell with 1M LiOH (aq.) and25°C and 50°C

• Gas O2, platinum counter electrode (CE), reversible hydrogen reference electrode (RE)

Potential range 0.1V - 1.8V vs. RHE


Bi-functional Oxygen-Electrodes: IrO2/- and Co3O4/Ag-electrodes

• CV´s electrodes 20 wt. % catalyst (IrO2, Co3O4

• Improved cyclingperformance due touse of IrO2 and Co3O4compared to pure Ag

0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0-150

-100

-50

0

50

100

Cu

rren

t d

ensi

ty [

mA

cm

-2]

Voltage vs. RHE [V]

Co3O

4/Ag

IrO2/Ag

Ag

No IR corr.

max. overpotential 1.5V

2.6V vs. Li/Li+

Current density @ 2.6V vs. Li/Li+ [mA cm-2]

IrO2/Ag 99,7Co3O4/Ag 107

N. Wagner , D. Wittmaier, German Patent Application, 2014

Overview EIS measurement points and CV with 1 mV/s at RT, 1 N LiOH , Ag-GDE

-0,3

-0,25

-0,2

-0,15

-0,1

-0,05

0

0,05

0,1

0,15

0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 2

Cur

rent

den

sity

/ A

cm

-2

Potential vs. RHE / V

Electrode 1 (high pressure) 25c



Electrode 2 (low pressure) 50c

EIS measurement point

Electrode 1 (high pressure) 25°C

Electrode 1 (high pressure) 50°C

Electrode 2 (low pressure) 25°C

Electrode 2 (low pressure) 50°C


Impedance measurements during Oxygen evolutionon Ag-GDE (high pressure), 1 N LiOH, 25°C

1 100 10K

5

10

20

15

50

|Z| /

0

15

30

45

60

75

90

|pha

se| /

o

frequency / Hz

a a a a a a a a a a a a a a a a aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

b b b b b b b b b b b b b b b b bbbbbbbbbbbbbbbbbbbbbbbbbbb

bb

b

b

b

b

b

b

b

bb

bbbbb

b

c c c c c c c c c c c c c c c c cccccccccccccccccccccccccccccccccccccc

cc

c

cc

c

d d d d d d d d d d d d d d d d ddddddddddddddddddddddddddddddddddddddddd

dd

d

a a a a a a a a a a a a a a a a aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

b b b b b b b b b b b b b b b b bbbbbbbbbbbbbbbbbbbbbbb

bb

bb

bb

bb

bbbb

b

b

b

bb

bbbb

c c c c c c c c c c c c c c c c cccccccccccccccccccccccccccccccccccccc

ccc

cc

c

d d d d d d d d d d d d d d d d dddddddddddddddddddddddddddddddddddddddddddd

OCV+100 mV

OCV+300 mV

OCV+500 mVOCV+700 mV

10 20 30 40 50

0

-30

-20

-10

10

Z' /

Z'' /

aaaaaaaaaaaaaaaaaaaaaaaa

bbbbb

bb

bbbb

bb

bb

bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb

cccccccccccccccccccccccccccccccccccccccddddddddddddddddddddddddddddddddddddddddddddddd

OCV+100 mV

OCV+300 mVOCV+500 mV

OCV+700 mV


Equivalent circuit used for evaluation of EIS during OCR and OER at different electrodes for Lithium-Air batteries


mZZe

Current collector GDL

electrolyte pores

porous layer

Zs1 ZsnZsi

ZpnZpiZp1

Z q1 Zqi Zqn

H. Göhr in Electrochemical Applications/97, www.zahner.de

Cylindrical homogeneous porous electrode model (H. Göhr)

Ions (H+, OH -,..)

I I

Por

e

Ele

ctro

de, p

orou

s lay

er

Electrolyte Zq

Zp ZS

Zo

Zn

Current (e-)


Potential dependency of total resistance duringORR at different electrodes, 1 N LiOH

1

10

100

0 200 400 600 800 1000

Res

ista

nce

/ Ω

Potential OCV minus x / mV

Electrode 1 (high pressure) 25cElectrode 1 (high pressure) 50cElectrode 2 (low pressure) 25cElectrode 2 (low pressure) 50c

Rtotal ORR


Potential dependency of charge transferresistance during OER

0,01

0,1

1

10

100

100 200 300 400 500 600 700 800

Res

ista

nce

/ Ω

Potential OCV plus x / mV

Electrode 1 (high pressure) 25cElectrode 1 (high pressure) 50cElectrode 2 (high pressure) 25cElectrode 2 (low pressure) 50c

R2 OER (charge transfer)


Potential dependency of charge transferresistance in oxide layer potential region (OER)

0

0,5

1

1,5

2

2,5

3

3,5

4

100 200 300 400 500 600 700 800

Res

ista

nce

/ Ω

Potential OCV plus x / mV




Electrode 2 (low pressure) 50c

R5 OER (oxide layer)


FIB-TEM picture of a Silver gas diffusion electrode

-8th IWIS 2015, Norbert Wagner

Main Limitations of the Zinc-Air Battery


“ZAS” innovation on the bifunctional air electrode


Thank you for your attention!Vielen Dank für Ihre Aufmerksamkeit!Gracias por su atención!Multumesc pentru atentie!

German Aerospace Center (DLR)

Institute of Engineering

Thermodynamics

Battery group


Documents

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