Electrochemical Properties of Materials for Electrical ... Properties of Materials for Electrical Energy Storage Applications Lecture Note 8 November 27, 2013 Kwang Kim Yonsei Univ., KOREA

  • Published on
    06-Feb-2018

  • View
    223

  • Download
    5

Transcript

Electrochemical Properties of Materials for Electrical Energy Storage Applications Lecture Note 8 November 27, 2013 Kwang Kim Yonsei Univ., KOREA kbkim@yonsei.ac.kr 39 Y 88.91 8 O 16.00 53 I 126.9 34 Se 78.96 7 N 14.01 Introduction 1 2 3 3 Battery System Ni-Cd Ni-MH Pb-SO4 *Direct Methanol *Polymer Electrolyte Membrane 1 PEM* Method Cylindrical Prismatic Polymer Hybrid Electric Vehicle Cell , DM* Method 2 Li-Ion mobile < IT Device >< Home Appliance >< House >< Automobile >< Industry > (Wh) (KWh) (MWh) Power train , IT Backup http://imagesearch.naver.com/search.naver?where=idetail&query=%C5%C2%BE%E7%B1%A4%B9%DF%C0%FC&from=image&ac=-1&sort=0&res_fr=153600&res_to=307200&merge=0&start=25&a=pho_l&f=tab&r=25&u=http%3A%2F%2Fnews.naver.com%2Fnews%2Fread.php%3Fmode%3DLSD%26office_id%3D112%26article_id%3D0000072735%26section_id%3D101%26menu_id%3D101http://imagesearch.naver.com/search.naver?where=idetail&query=%C7%B3%B7%C2%B9%DF%C0%FC&from=image&ac=-1&sort=0&res_fr=0&res_to=0&merge=0&start=51&a=pho_l&f=tab&r=21&u=http%3A%2F%2Fblog.naver.com%2Fmclee_boy%3FRedirect%3DLog%26logNo%3D40031156213 : 07 63 15 170 (2.7 ) 1 195 8 71 SLI () 181 86 1 SLI 2 U$337 HEV HEV 9 76 2 U$580 15 U$1,700 07 U$626 (Source : , IIT, Frost&Sullivan, SDI) 2 (Cd, Pb) , IT , IT mobile . Ni-Cd Ni-MH Li-ion 2.0V 1.2V 1.2V 3.7V Li-ion 9.7 3.2 1.9 1 Li-ion 6.7 3.3 2.5 1 (07,$/Wh) 0.04 0.38 0.36 0.51 (/) : Set : (, ) (Cd,Pb..) Li-ion High Energy Density High Voltage No Memory Effect (NIi-Cd) (Ni-MH) , 1/2 20~50% . 3 , , . Memory effect . Memory Effect . (Cd) (Pb) (Hg) , . High Rate Discharge Fast Charge & Long Life Cycle 20C mA Note PC, DVC, DSC Drive Large Power . 1CmA, 4.2V CC-CV . 500 / Li-ion 5 , : , : (Graphite) Separator : , : Cap Assy : Can : : LiMO2 etc. : Carbon - Acetylene black or - Ketchen black : PVdF Al(12~30) - - , () - * LiMO2or LiM2O4 * LiMMO2 (M = Co, Ni, Mn, Cr, Fe ...) LICoO2 LINi0.8Co0.15Mn0.05O2 g (coin cell) LICoO2 LINi0.8Co0.15Mn(Al)0.05O2 LIMn2O4 LIMn2O4 : Graphite etc. : SBR : CMC Cu(8~20) - / () . : (dendrite) : layer Graphite Si/Graphite Oxide/Carbon 200 nm200 nmSiSiOxSiOxSiOxSiOxSi-oxide Gen.I Gen.II Gen.III KMFC/ MCF PHS Smilion-A CZ50 (DAG-A) MKL . - . - . - . Al foil Cu foil (, ) 1) / . 2) , . 3) . PVDF : Poly Vinylidene Fluoride SBR : Styrene Butadiene Rubber CMC: Carboxyl Methyl Cellulose (Electrolyte) !!! ; . (Carbonate ) ; Li-ion 2 Li-ion . , salt solvent . LiCoO2 + CnCh earg Disch earg Li1-xCoO2 + CnLix (salt) : Li- ion . (LiPF6) ( ) (solvent) : . (additives) : . 1.15M EC/EMC/FB + UFEC3% + SA0.75% + LiBF4 0.2% + BP1.5% + CHB1% + HA30 5% Main Additive I Additive II Trade-Off Main (Salt, Solvent) Li () , , , Add I SEI layer , Add II , , , Separator() Separator 1) , . 2) . 3) shut down, , . Separator PE (Polyethylene) PP/PE/PP (Polypropylene) Li-ion Cell Steel , () , Size Flexibility Li-ion Cell Cylindrical Prismatic Polymer No. 1 Cap-up 2 PTC Safety Device 3 CID Vent CID:Current Interrupt Device 4 Vent Gas 5 Gasket , / 6 Top Insulator Tab Jelly Roll Short 7 Can Jelly Roll Housing 8 Bottom Insulator Jelly Roll Can Short 9 Jelly Roll //Separator 10 Tab Cylindrical Cell Prismatic Cell No. 1 Washer Pin Can 2 Pin 3 Gasket , / 4 Al ball 5 Cap plate (Safety Vent ) 6 Insulator Terminal Plate Cap Plate Short 7 Terminal plate Pin Tab 8 PP Case Tab Can , J/R 9 Can Jelly Roll Housing 10 Jelly Roll //Separator 11 Bottom Plate 12 Tab Polymer Cell No. 1 Tab 2 Tab 3 Strip Tape Tab Pouch 4 Pouch Jelly Roll Housing 5 Jelly Roll //Separator Capacity Voltage charge discharge LiCoO2 : 95~96% LiMn2O4 : 99~100% LiNiO2 : 85~88% Capacity Voltage charge discharge graphite : 89~94% amorphous carbon : 80~87% alloy : 50~75% L4Ti5O12 : 97~100% Cathode Anode . Cathode Anode 1st Cycle Charging 1st Cycle Discharging Cathode Anode + + ( > : ) Half Cell & Full Cell Full Cell Half Cell Half Cell Voltage = Potential difference between positive and negative Half cell potential A+ T+ W+ B+ A+ T+ B+ A- T- W- B- A- T- B- = = = (LL) = { (A+ LLA) + (B+ LLB) } W+ LLA : A . ( ) ( = + + ). / . J/R / SEI Layer Decomposition of electrolyte reductively on the carbonaceous anode Prevention of further decomposition of the electrolyte components (passivation layer) EC is an essential component of the solvents Charging capacity Discharging capacity =reversible capacity irreversible capacity Coulombic efficiency = 1st discharging capacity / 1st charging capacity = reversible cap. / (reversible cap. + irreversible cap.) SEI (Solid Electrolyte Interface/Interphase) Li , SEI SEI Layer Electrolyte decomposition at the anode SEI formation Electron consumption irreversible capacity SEI Layer The SEI layer is essential for the stability of Lithium secondary cells using carbon anodes BUT the SEI layer increases the cell internal impedance and reduces the possible charge rates as well as the high and low temperature performance. Excessive heat can cause the protective SEI barrier layer to beak down allowing the anode reaction to restart releasing more heat leading to thermal runaway. The thickness of the SEI layer is not homogeneous and increases with age, increasing the cell internal impedance, reducing its capacity and hence its cycle life. SEI Stability Suppress additional electrolyte decomposition Resistance Increase cell impedance Reduce charge rate * SEI ( , ) SEI Layer SEM images of graphite SEM images of LiMn2O4 SEI , SEI Layer unstable SEI Decomposition of SEI New SEI formation Thermal high temperature operation Electrochemical charging, reductive potential Mechanical volume change stimulus Electrolyte decomposition Charge consumption (capacity loss) Ohmic / Film resistance increase (power loss) Electrolyte loss, gas evolution, thickness increase Better SEI Better Performance Thin Dense Stable Flexible (formation) ? N/P Ratio N/P ratio : ( N/P) = ( ) / ( ) * 100 100 (105~120) ; 5~20% : , 0.5~1 mm (+) (-) separator N/P Ratio ? (+) (-) (+) (-) , edge , : LiCoO2 Li1-xCoO2 + x Li+ + x e- : C6 + x Li+ + x e- LixC6 , 1. , 2. , , (electroplating) 1. (internal short) 2. 3. , N/P Ratio ? Material and Design Options for Avoiding Lithium-Plating during Charging, Kevin Eberman, Medtronic Energy and Component Center / zero gap (LiCoO2/C) / 1 mm gap (LiCoO2/C) / zero gap (LiCoO2/Li4Ti5O12) Li-metal electroplating Li4Ti5O12 1.55 V Li N/P Ratio NP = 1.12 . NP ( ) = [ x x ][ x x ] A LL 22.94mg/cm2 A LL 10.05 mg/cm2 LL 45.88mg/cm2 LL 20.10 mg/cm2 145.0 mAh/g 365.0mAh/g 96.0% 97.5% / (: mm). 43.5mm/44.5mm. ? 1115mAh(or 1116mAh) ( . A B (LL) . ) Full Cell + Mixing - Mixing / / V/D Winding Can insert Tab Crimping Pressing / Press marking Tray OCV / IR Rank Cell Formation QA Core Pack Pack QA Hard Pack / Slitting - & SPEC L/L A,B , , Pressing , , , V/D ,V/D , - - ,/ J/R J/R Can , Can/Ass'y & L/P ATC Lot,Tray - , (43) (IR/OCV) 1 , 2 (IR/OCV) 3 (IR/OCV) 2 () (Rank) SET , , Concept SET , Cost Balanced Product + Cost Performance , // // Needs Needs Energy density Safety Cost Power Energy density http://news.naver.com/news/read.php?mode=LSD&office_id=029&article_id=0000092037§ion_id=105&menu_id=10550 50 100 100 150 150 200 200 250 250 300 300 350 350 SEI (Li alkyl carbonate LiF, Li2CO3) PE LixCoO2/EL IR heating ( ) Passivated Li/EL () LixC6 EL (EC ) SEI : IR heating - - 2 short - Li short - - melt down () - LiCoO2 - IR heating Safety 1) / Li0.5CoO2 + 0.1C3H4O3 0.5LiCoO2 + 0.5CoO + 0.3CO2 + 0.2H2O, H=-1.2kJ/g 2) ( ) Li0.5CoO2 0.5LiCoO2 + 1/6Co3O4 + 1/6O2, H=-0.061kJ/g 3) C3H4O3+5/2O2 2H2O+3CO2, H=-0.8kJ/g 4) H=-0.139kJ/g 10m Hot Plate , . 130 2/150 10 200 / . . / Cell 10m /1.9m 10 CID PTC/Vent/ Separator Mode Mode ,

Recommended

View more >