ENTEK LR Separators: Improved Electrical, Mechanical, and Oxidation Resistance. R. Waterhouse, D. Merritt, D. Walker, A. Brown, C. Rogers, E. Hostetler, C. La, and R.W. Pekala ENTEK International LTD ENTEK International LLC March 22, 2016 Interbat, March 21-24, Moscow, Russia

OUTLINE OF PRESENTATION  Introducing LR and XLR separators from ENTEK.  Wettability  Pore structure  Electrical resistivity  Mechanical strength  Oxidation resistance  Electrochemical compatibility  Battery test results 2 Interbat, March 21-24, Moscow, Russia

WHAT IS DIFFERENT ABOUT LR AND XLR SEPARATOR ?  New Process Technology  New capital equipment installed  Current production at UK plant  US plant in 2016  Advanced Formulation  Unique raw materials  Increased polymer content (XLR > LR > STD) STD = Entek Standard Separator 3 Interbat, March 21-24, Moscow, Russia

SEPARATOR ER – WHAT MAKES LOW RESISTANCE?  Separator resistance is a function of electrolyte resistivity (acid) plus the design, pore structure, and composition of the separator.  Resistance of electrolyte within a porous structure (Ω): R = pLτ 2 / P A Where p = resistivity of the electrolyte, f ([C], T) L = thickness of the separator (design) τ = tortuosity of the pore path (structure) P = porosity filled with acid (structure and composition) A = cross-sectional area through which ions flow  LR and XLR separators provide:  Higher porosity = more volume for acid  Lower tortuosity = shorter conduction path for ions  Sustained wettability = rapid and complete filling of pores 4 Interbat, March 21-24, Moscow, Russia

WETTABILITY  In-situ surface modification of the polymer promotes wetting.  LR separator wets out more rapidly with water or sulfuric acid compared to STD separator  LR separator demonstrates sustained wettability even after repeated washing and drying steps Washed and dried 4 x before re-wetting with water droplet shown above STD t= 0 secs LR t= 0 secs Initial wetting, with water, of ENTEK standard material. 5 Interbat, March 21-24, Moscow, Russia

MD Freeze Fracture UHMWPE fibrils provide strength Silica Aggregates provide wettability 6 Pores for acid provide conductivity

PORE STRUCTURE Surface Fracture XLR LR STD 7 Interbat, March 21-24, Moscow, Russia Increasing Porosity Low Resistance separators have a more open surface structure

HG POROSIMETRY --- LR VS STD LR Separator gives significantly higher porosity than STD separator Note: 0.15 XLR has same porosity as 0.25 LR 8 Interbat, March 21-24, Moscow, Russia Increasing pressure

HG POROSIMETRY --- LR VS STD LR Separators have larger median pore size than STD separator 9 Interbat, March 21-24, Moscow, Russia Increasing pressure

WETTED POROSITY INCREASED GE +13% The pore volume wetted by the electrolyte is also significantly increased, but not enough to explain all the decrease in resistance in this new product. 10 Interbat, March 21-24, Moscow, Russia

TORTUOSITY REDUCTION GE The tortuosity of the pores wetted by the electrolyte is decreased. 11 Interbat, March 21-24, Moscow, Russia

ER REDUCTION FROM HIGHER POROSITY AND LOWER TORTUOSITY GE -48% Increased wetted pore volume and decreased tortuosity result in a large decrease in resistance. 12 Interbat, March 21-24, Moscow, Russia

ELECTRICAL RESISTANCE VS. BACKWEB LR separators have 35-50% lower ER values compared to STD separators GE_LR separators have 35-50% lower resistance compared to STD separators. Resistance is linear with backweb thickness. 13 Interbat, March 21-24, Moscow, Russia

ELECTRICAL RESISTANCE 0.15 XLR has more polymer Resistance is equal to 0.15 LR 14 Interbat, March 21-24, Moscow, Russia

MECHANICAL PROPERTIES 15 Interbat, March 21-24, Moscow, Russia

BACKWEB PUNCTURE LR Separators have good puncture strength and outstanding toughness 16 Interbat, March 21-24, Moscow, Russia

BACKWEB PUNCTURE With higher polymer content, 0.15 XLR can replace separators with thicker backwebs. 17 Interbat, March 21-24, Moscow, Russia

SHOULDER PUNCTURE With higher polymer content, 0.15 XLR, has higher puncture strength than thicker competitor separators competitors 18 Interbat, March 21-24, Moscow, Russia

WHAT IS TOUGHNESS ? ENERGY-TO-RUPTURE  ENTEK separators are considered “tough” because they exhibit a combination of strength and elongation that requires significant energy before rupture (puncture) occurs.  Toughness or energy-to-rupture is represented by the area under the load-elongation curve for a separator as shown in the following slides. 19 Interbat, March 21-24, Moscow, Russia

PUNCTURE STRENGTH --- LOAD VS EXTENSION Peak value = puncture strength Shaded area under curve = energy-to-rupture 20 Interbat, March 21-24, Moscow, Russia

BW PUNCTURE STRENGTH --- LOAD VS EXTENSION Material Puncture Strength (N) Puncture Energy (mJ) Entek 0.15 XLR Entek 0.2 LR D 0.2 BW MP 0.2 BW A separator may show higher puncture strength at 0.20 mm bw, but significantly lower energy-to-rupture than 0.20 LR or 0.15 XLR 21 Interbat, March 21-24, Moscow, Russia 0.2MP 0.2 D 0.2LR 0.15XLR

OXIDATION RESISTANCE 22 Interbat, March 21-24, Moscow, Russia

SEPARATOR OXIDATION RESISTANCE  Test methods  Perox 80 (BCIS-03B-22)  Potassium dichromate  Oxidation induction time  Electrochemical oxidation test  High temperature battery life test  Material considerations  Polymer matrix  Residual oil  Oil / PE ratio 23 Interbat, March 21-24, Moscow, Russia

PEROX 80 TEST PROCEDURE (SIMPLIFIED) BCIS-03B-22 H 2 O Boil 20 min. 10% H 2 O 2 + H 2 SO 4 80°C for 20, 48, 72 hr Cut samples Tensile And Puncture Test Rinse and keep wet 24 Interbat, March 21-24, Moscow, Russia

PEROX % XMD ELONGATION VS EXPOSURE TIME Polymer content : XLR > LR > STD 25 Interbat, March 21-24, Moscow, Russia Standard LR and XLR Standard, no oil

PEROX PUNCTURE STRENGTH VS EXPOSURE TIME Polymer content : XLR > LR > STD 26 Interbat, March 21-24, Moscow, Russia Standard LR and XLR Standard, no oil

OXIDATION RESISTANCE: 0.25 STD COMPARED TO 0.15 LR AND XLR Polymer content : XLR > LR > STD 0.15 LR and XLR have better elongation than 0.25 STD after 48 hrs in oxidizing solution. 27 Interbat, March 21-24, Moscow, Russia 0.15 LR and XLR have better durability after oxidation than 0.25 STD.

OXIDATION RESISTANCE: 0.25 STD COMPARED TO 0.15 LR AND XLR 0.15 LR and XLR have higher puncture strength than 0.25 STD after 48 hrs in oxidizing solution. 28 Interbat, March 21-24, Moscow, Russia Polymer content : XLR > LR > STD 0.15 LR and XLR have better durability after oxidation than 0.25 STD.

ELECTROCHEMICAL CHARACTERIZATION 29 Interbat, March 21-24, Moscow, Russia

LR SEPARATOR --- ECC TESTS RESULTS ARE POSITIVE Good electrochemical compatibility exhibited in anodic and cathodic scans. No significant peak shifts and no new peaks for positive or negative electrode scans. Small decrease in hydrogen evolution detected in the cathodic scan. Decreasing H2 current 30 Interbat, March 21-24, Moscow, Russia Cathodic Scan: Negative electrodeAnodic Scan: Positive electrode

TYPICAL BATTERY RESULTS  LR separator is qualified in multiple EFB designs in Europe  Internal battery resistance (Hioki meter)at 20 °C: reduced by micro-ohms compared to battery with Entek standard separator  CCA: Increase in U 10 values of mV at -18 °C  Water loss: < 2.5 g/Ah at 14.4 V and 60 °C  Good high temperature oxidation resistance demonstrated in high temperature cycle tests 31 Interbat, March 21-24, Moscow, Russia

SUMMARY  ENTEK has developed a new technology to manufacture low resistance separators, LR and XLR, at our UK plant. This same technology will be installed at our US plant in  Low resistance separators, in several backweb and overall thicknesses, are being sampled to battery manufacturers in Europe, North America, South America, and Asia.  0.15 LR and 0.15 XLR outperform many 0.25 STD separators in mechanical strength and oxidation resistance. Thinner backwebs can be used in many existing OEM battery designs. Спасибо 32 Interbat, March 21-24, Moscow, Russia